Manufacturers are always looking for ways to cut costs and increase the efficiency of their plants. One way to do so is through the use of AC drives. Many users of AC drives are aware of the significant reduction in energy consumption that is offered when an AC drive is used to control the speed of a centrifugal fan or pump. Using a drive to operate these devices at, for example, 80 per cent of their rated speed, can cut energy costs in half. What is often overlooked is the far-reaching impact on the overall health of automated systems that AC drives can offer. In fact, converting a process from fixed speed to variable speed in itself can reduce wear and tear and maintenance requirements for mechanical systems by reducing start/stop cycles and eliminating vanes, dampers, valves and other mechanical system components. In addition to these benefits, understanding the features offered by a variable speed drive can significantly reduce system maintenance and overall operating costs.MonitoringDrives have somewhat limited monitoring capabilities compared to devices exclusively dedicated to preventive maintenance. By nature, however, they do monitor motor current and speed, and can perform protective functions based on that information. In an example of an intelligent motor control approach, PLCs and other controllers connected to a drive via a communications network can also monitor these values and provide warnings and reminders to maintenance personnel that something in the process has changed. By monitoring the motor current and speed, it may become obvious that a motor is loaded more heavily than normal and that the mechanical system should be checked before a failure occurs. Networked data helps users decrease downtime and protect machinery.Motor overloadIn more extreme situations, the drive itself will act to protect the motor. Almost all drives today have a built-in electronic motor thermal overload feature. When a motor is in a state of severe exertion, beyond its safe operating limits, the motor overload feature can reduce the output current or shut off the motor and protect it from thermal damage or catastrophic failure. Motor overload software uses an algorithm incorporating motor current, speed and time as inputs to model the temperature of the motor. This may also be done with thermister feedback directly from devices buried in the motor windings, using actual temperature readings to determine motor stress. Multi-motor applications–those using one AC drive and more than one motor - will require the motor overload to be disabled since the drive would be unable to distinguish each individual motor's current to provide protection for individual motors. These applications require more advanced machine monitoring devices that can accept data from multiple sources to alert personnel of impending faults and failures. S curveS curve and controllable acceleration and deceleration are other, often-overlooked drive features that can help to improve process performance and reduce maintenance. When a load transitions from steady state speed to accelerating or decelerating, the transition is usually instantaneous. The same is true when the transition is reversed. While not as dramatic, it is the industrial equivalent of "popping the clutch" on a stick-shift car. This jerking action puts considerable stress on mechanical components. In belt-driven systems, belts can fly off or break. In geared systems, the process can wear or break gear teeth. AC drives can control this phenomenon through the S curve feature. Using the same analogy, it is the process equivalent of "feathering or slipping the clutch" to ease into acceleration or deceleration. S curve controls the jerk or rate of change of acceleration. It has long been recognized as an aid in the handling of very light conveyor loads, such as in a bottling line, but it can also play a significant role in extending the life of mechanical components. Lower mechanical stress means lower maintenance costs. Flying startThe flying start feature is used to reconnect the drive to a motor that is already spinning and, as quickly as possible, resume normal operation with minimal impact on load or speed. When a drive executes a normal start, it initially applies zero hertz and ramps up to the commanded frequency. If the drive is started in this mode with the motor already spinning, large currents will be generated and an overcurrent trip may result if the current limiter does not react quickly enough. The likelihood of an overcurrent trip is further increased if there is a residual flux on the spinning motor when the drive starts. Even if the current limiter is fast enough to prevent an overcurrent trip, the end result is still to effectively decelerate the motor to a very slow speed and then re-accelerate it to the desired frequency. This can place extreme mechanical stress on the application, potentially causing costly downtime and repair costs while decreasing productivity. In flying start mode, the drive's response to a start command will be to identify the motor's speed and begin its output synchronized in frequency, amplitude and phase to that of the spinning motor. The motor will then be reconnected at its existing speed and smoothly accelerated to the commanded frequency. This process eliminates overcurrent tripping and significantly reduces the time for the motor to reach its desired frequency. Since the motor is "picked up" smoothly at its rotating speed and ramped to the proper speed, little or no mechanical stress is present.In some applications, such as large fans, wind or drafts may rotate the fan in the reverse direction when the drive is stopped. Flying start will determine, not only the speed of the fan, but also its direction of rotation. For faster uptime, it executes a safe, controlled deceleration to zero speed and then accelerates to the commanded system speed.Skip frequencySome machinery may have mechanical resonance points that must be avoided to minimize the risk of equipment damage. Many of us have experienced a severe "shimmy" in the steering wheel because the car's front end is out of alignment. Experience shows us that this shimmy can be severe at one speed, but speeding up or slowing down by just a few miles per hour will make the vibration stop. The car's misaligned front end has a mechanical resonance only at specific speeds. All rotating mechanical systems have these resonant points and many can be damaged if allowed to operate continuously at these speeds, resulting in system downtime and increased maintenance costs. Drives offer a feature called skip frequencies or critical avoidance frequencies to ensure that the motor will not continuously operate at one or more of these vibration points. The frequency that causes the resonance is programmed into the skip frequency parameters, and a bandwidth is programmed around the frequencies to create a skip band that avoids the vibration-causing areas. Most drives offer multiple skip frequency parameters to accommodate different resonance points. Normal acceleration and deceleration are not affected by the skip frequencies. The drive output will ramp through the band uninterrupted. When, however, a command is issued to operate continuously inside the established band, the drive will alter the output to remain outside the band until a new command is issued.When mechanical resonant frequencies are identified and drives are programmed to avoid continuous operation at those frequencies, wear and stress from vibration are greatly reduced. Current limitAn AC drive can control the amount of current it supplies to a motor. Current limiting functions are often used to prevent mechanical damage. By limiting current or shutting down the operation, AC drives can reduce mechanical damage. In addition to current limiting to reduce torque, many drives have a feature called an electronic shear pin - a modern take on an old concept. Outboard boat motors, for example, are usually equipped with mechanical shear pins. Rather than break the propeller if it were to strike a rock, the shear pin breaks, mechanically disconnecting the propeller from the motor and saving the mechanical system (and the boat owner's pocketbook). Similarly, a drive's electronic shear pin feature can define a current limit level that would cause damage. If the torque in the motor ever exceeds the set limit, the drive will automatically shut off the motor.By limiting torque to a set level, AC drives provide good protection for systems that can become jammed. Chain breakage and other damage can be avoided by not allowing a motor to power through the jam.Advanced integrationWith the increasing complexity of manufacturing systems, users want quick configuration to shrink development time. Once a project is installed and running, they also want access to diagnostics and maintenance data to maximize uptime. With the ability to integrate into one information platform, users can consolidate control disciplines into a single, integrated environment that offers considerable time- and cost-saving advantages. Spreading the wordTaking advantage of system architecture and drive features doesn't require a great deal of special training. Users need only be aware of the features and the benefits that the drives provide. By taking full advantage of the wide array of techniques already available, plant engineers can minimize the stress and abuse placed on valuable plant machinery, increase equipment uptime and reduce maintenance costs - key elements for boosting the bottom line.Doug Weber is the marketing manager for the Allen-Bradley drives business at Rockwell Automation in Mequon, Wis.
In the highly competitive automotive industry, time to market is critical. Car manufacturers require their suppliers to provide them with a quality product, fast. This puts pressure on the suppliers to incorporate a manufacturing process that meets the growing demands of automakers. sitting-pretty-manufacturer-brings-just-in-time-seat-production-to-canadian-plants Seat manufacturing, in particular, demands a high degree of versatility and flexibility. Japanese seat manufacturer TS Tech did not take this challenge sitting down. The company produces the complete seating system for the Honda Ridgeline pick-up truck at its plants in Newmarket and Markham, Ont. As a Tier 1 supplier to Honda, TS Tech is closely integrated into the vehicle assembly line. The seats required must flow just-in-time into the continuing process. That means they must be supplied in the right sequence and be the appropriate seat for each individual vehicle on the assembly line. Achieving this demands perfect logistics and a manufacturing process that permits quick changes between the widest varieties of seat type, upholstery and colour. Since there is no intermediate stock available, downtime from technical issues must be restricted to an absolute minimum.When Honda upgraded to a new generation of seats with additional sensors integrated to increase safety - including occupancy sensors that detect not only the presence of a person, but also their approximate weight and seat position so that, in the event of an accident, the airbags deploy accordingly - TS Tech, too, had some upgrading to do where its manufacturing system was concerned. The company's previous manufacturing system was a succession of individual workstations, which were not integrated to each other. Trouble-shooting was a very time-consuming process, since any single fault required an engineer to come to the line with a laptop, diagnose it and rectify it directly.TS Tech turned to Siemens to update its entire manufacturing system. What resulted is a system that automatically recognizes the causes of defects, and allows increased quality with practically no downtime.Zero defects, zero stoppagesThe manufacturing system installed at TS Tech is characterized by a particularly high degree of assurance against downtime. Since Siemens provided the entire system, from the commissioning, startup and engineering design to the controls hardware, conveyors and tooling, all components integrate together without problems, and function seamlessly together. From the incoming uninterruptible power supply all the way down to the last push button, everything forms a complete solution, which underscores the concept of totally integrated automation.The technical level of the new manufacturing system is characterized by an S7-400 PLC with a second S7-400 PLC used as a backup, along with Ethernet networking and Profibus links to the sensors and actuators. In addition, the system includes Moby RFID (radio frequency identification), AS interface fieldbus system, Step7 Graph programming language, and a WinCC user interface.All parameters for the entire system can be displayed on the central human machine interface (HMI) station. Whether the fault is a networking problem, an incorrectly set torque gun or an operator error, PDiag, a software engineering tool used for diagnosing automation systems, allows any fault to be diagnosed and thus addressed and rectified in the shortest possible time. This tool displays the presence of a process fault automatically on the HMI. Configuration is all that is required to apply this to the system. No additional PLC or HMI programming is required by the engineers, which greatly reduces engineering and commissioning time.Complex flexibilityDespite the complexity of the system, its flexibility allows it to be modified to satisfy future needs. Tool changes can easily be accomplished, and more stations can be added or removed as required. Even the layout can be modified without problems, if needed. Since commissioning, the system has been upgraded to increase the output by 25 per cent. This was accomplished by TS Tech's internal resources with only minor modifications.Total quality controlThe new system has not only brought the entire manufacturing process under control at TS Tech, but it has also improved quality control. The seamless monitoring of all functions generates comprehensive data on each individual product. Every individual bolt torque, the serial number of the air bags, all the test results, any rework necessary, is all logged instantly. The data is then archived on a central server for 10 years, so that causes of problems can be traced back.Satisfaction TS Tech is extremely impressed with the Siemens solution. "The diagnostic capabilities of the Siemens system open up completely new opportunities for us to achieve our objectives," says Arif Khan, project manager at TS Tech. The automatic diagnostic capability achieved with SCADA has attracted great attention at the company's head office in Japan, and has led to consideration of its adoption to other manufacturing locations worldwide.Based on this positive experience with the Honda Ridgeline seats, TS Tech has awarded Siemens an additional turnkey system similar to the first one to produce the seats for the Honda Civic.Today, thanks to Siemens, TS Tech is sitting pretty, as it meets Honda's deadlines and demands with no worries.Dominic Caranci is the automotive sector manager for Siemens Canada Ltd.
Imagine a manufacturing plant where robots are sophisticated enough to understand their environment and choose the best path to achieve a goal. Imagine robots capable of working together as a team to solve problems. Such robots, endowed with high-level cognitive capabilities - including perception processing, attention allocation, anticipation, planning and reasoning - would greatly expand the possibility of flexible manufacturing because they would be able to see, feel, touch and reason within the confines of unpredictable environments. This isn't your father's robot. "The difference with cognitive robotics is that instead of programming a robot with the sequences of mechanical actions it should perform when certain conditions arise, a cognitive robot is programmed with the logic behind the mechanical actions it can perform and how to synthesize these mechanical actions in order to bring the environment to a specific state," says Stavros Vassos, a PhD student working in the cognitive robotics group at the University of Toronto. Do cognitive robots exist today in an industrial environment?"To my knowledge, there are no industrial applications where the cognitive robotics design paradigm is used," says Vassos. But his group's research focuses on a high-level programming language for controlling robots. In this language, one can specify the available actions that the robot can do, including actions that affect the environment and actions that extract information from the environment using its sensors; the objects and properties of the environment and how these change for each of the possible actions the robot can do; and a high-level control program that specifies the behaviour of the robot using the properties of the environment as control-flow expressions and the actions that the robot can do as basic statements.Michael McCourt, president of Stratford, Ont.-based D&D Automation, engineering specialists who provide customized controls and manufacturing intelligence solutions, agrees that we have not yet seen "true cognitive robots" applied in an industrial setting. "A cognitive robot would need to 'understand' its environment and choose the best path to achieve a set goal," says McCourt. "A truly cognitive working environment would be capable of almost infinite flexibility to build variations of any product...We are seeing robotics with ever-increasing input devices like vision, touch, pressure and auditory inputs that allow for ever-increasing complexity in manufacturing. We are reaching a point where the robotics certainly appear to be cognitive, but the leap to true cognitive robotics or truly cognitive manufacturing is a long way off."McCourt says that costs are too high and that the technology just isn't there yet, particularly where the hardware and software are concerned. "Hardware will have to be capable of changing or 'growing' like a human brain to reflect the requirements of the software. I also believe that the software will have to be able to develop new algorithms or 'thought' and drive the hardware in the desired direction," he says. "We will need to work on some range of motion limitations so that robotics are less limited in their ability to do physical work. Without this range of motion, the power of the cognition is wasted. Communications speeds will also need to be significantly sped up in order to bring a series of cognitive pieces together in a collaborative manufacturing process."To make cognitive robots a reality, D&D Automation is currently working on developing the sensory requirements and the range of motion that cognitive robots need to be truly cognitive. ABB, a supplier of industrial robots, is working with what it describes as cognitive robotics to transform manufacturing processes. "At ABB, we use the phrase 'cognitive robotics' to describe robots that can sense and react to changes within the industrial work environment," says Steve West, ABB's business development manager, vision technologies. "Traditionally, robots have been limited to specific commands and have been unable to respond effectively to variations within a process. Robots working in factories today are able to utilize capabilities such as vision guidance, force sensing and voice recognition."ABB is currently applying what it describes as cognitive robotic technology in the assembly of torque converters. "This process requires a robot to both see and feel," explains West. "To assemble a torque converter into a transmission requires that the part be seated onto a series of spline gears. Up until a few years ago, only humans were capable of such a task because of our innate ability to sense force, shimmy the part, sense force again, and then finally seat the converter onto a gear."West says that ABB is working with advanced technology using algorithms that give robots the ability to create a hypothesis so that they may interpret a random situation and take the appropriate action. "Most manufacturers have capitalized on robotic technology to stay competitive, but there are many areas of the factory that remain labour intensive," explains West. "If you tour factories today, you'll see incredible automation technology and then walk 15 yards and see something like humans putting wheels on cars manually. We're still working to solve labour-intensive manufacturing operations using robots. It's only that these robots must have some ability to perceive and respond to changing inputs, much like humans do all day long without even thinking."To achieve this, there are many challenges that have to be overcome. "Aside from limitations in processing speeds, the greatest challenge of cognitive robotics is to avoid point solutions and to instead provide a software and hardware platform that can solve families of problems with a high degree of reliability," says West. "Every day we see customers with a desire to automate what are really simple operations for humans, but the technology is not yet available for the application of robots. That's why we keep funding R&D and believe this to be a good business for now and the foreseeable future."Moving forward"It is possible that as the techniques related to cognitive robotics become more powerful and the implementations of cognitive robots more robust, we will see cognitive robots replace humans in more advanced tasks that currently robots cannot safely perform," says Vassos. "For instance, a futuristic scenario may involve cognitive robots that consist of modules that come with a representation of their parts and the dynamics of the available mechanical actions they can perform. The modules can then be combined and incorporated into industrial applications by programming only at the level of task specification, while the low-level details are sorted out by reasoning that the cognitive robot does by itself."Beyond the technological hurdles that need to be overcome, Vassos says that there needs to be more collaboration between industry and academia to determine the needs of industry.And, McCourt adds, "We need people who think and dream big." What makes up a cognitive robot?By Stavros Vassos, PhD student, University of TorontoCognitive robotics is a design paradigm that, when applied to robotic agents (in contrast to software agents), involves taking care of issues that lie in several different fields of research and applications, including: 1. The mechanical part of the robot that is responsible for movement and affecting the environment (e.g. mechanical arms, the body, the motors);2. The software and hardware parts responsible for getting meaningful information from the environment in which the robot is situated (e.g. the hardware and the information processing software for doing feature extraction from visual images and sound);3. The software part responsible for the representation of the environment and the way that the robot can interact with it (e.g. a logical specification of the properties of the environment as well as how these are affected by the available actions that the robot can perform);4. The software part responsible for the specification of the task that the robot should do based on the previous representation;5. The software and hardware parts that make use of the representation of the environment and the specification of the task that the robot should do to compute the behaviour of the robot at any given moment; and6. The software and hardware parts that provide the interface between the reasoning component and the actual sensors and actuators in the environment.
The continuous struggle to deliver top quality products while balancing optimal throughput is driving manufacturers to seek more intelligent tools to help manage their processes.The effects of quality bottlenecks can be felt across the entire line and affect a plant's profitability. Additionally, as the manufacturing world is transitioning through the paradigm shift of the lean manufacturing concept, based in large part on the Toyota production system, it has increased the impact of bottlenecks on the production line.As accountability in the plant increases, quality professionals need to have more insight into the processes on the production line that are delivering quality so they can then control and adjust them to meet quality and yield goals.Increasingly, manufacturers are turning to solutions based on manufacturing intelligence. This refers to applications and technology, including systems and software, that power on-demand, real-time quality testing and monitoring to help manufacturers capture and act upon detailed information throughout the manufacturing process. Its application enables manufacturers to proactively address the quality bottlenecks on their lines so that they can remain competitive.Without the right data, there is no intelligenceThe first step in gathering manufacturing intelligence is recording the data from the manufacturing line and processes. All too often, the process- and product-monitoring systems that inspect quality along the line do not feed much, or any, data into a centralized database. This means that critical data is lost, leading to low or no intelligence. Fortunately, most plants already have the IT infrastructure in place to link these test systems to a common database. The data collected can include serial number, model number, station name, time and date stamps, pass-fail results, key parameters and measurements, and, ideally, the complete process signature for each operation.Identify the top issuesRaw data is important but doesn't provide the information required to make decisions and improvements. It actually can be overwhelming to have hundreds or thousands of individual records. It is amazing how many quality managers need to spend hours of their time using custom, manual methods to produce reports. The use of analytics software can automate much of this to make sense of all the data.The Pareto principle is well known and applied in manufacturing. In a Pareto chart, the problems are organized from left to right in order of importance or occurrence. The old 80/20 rule is usually true of most processes, meaning 20 per cent of the effort can fix 80 per cent of the issues. A Pareto chart helps a manufacturer rapidly understand this. When applied to managing quality, it helps quality practitioners focus their attention on the issues that will have the greatest return. The Pareto chart, as shown in Figure 1, tells the quality manager the best place to start and enables him or her to monitor the progress of changes. Further manufacturing intelligence is required to see what caused the key issues before any fixes can be determined.Figure 1Identifying the root cause of a problemThe next very important step is tracking down the cause of higher-than-desired failure rates on a production line, which is often very difficult to do, especially without the right information. The following real-world example illustrates how data collected from the manufacturing floor can be used to identify the root cause of a problem.A quality engineer in an automotive powertrain plant uncovered a higher-than-normal failure rate of electronic throttle bodies at a cold-test station. This failure rate of 1.27 per cent affected 180 engines per month. Using manufacturing intelligence software to create a picture of the process signatures from the test data on all of the throttles, the engineer was able to see which parts passed, which parts failed, and the shape of the normal failures with anomalies (See Figure 2). These anomalies in the signatures were within the overall pass-fail limits set for the process, but they clearly represented the parts causing issues later at the engine cold-test station. A drill down on the apparent anomalies provided the serial numbers of parts that had passed the first test and failed the final cold test.Figure 2The engineer then conducted further analysis to identify the source of the problems. Seventy-seven per cent were due to stuck or sluggish throttles that the current test stand algorithm couldn't catch, and 23 per cent were due to upstream process failures that had not been identified until this point. This intelligence was then applied to the production floor to prevent the reoccurrence of these issues. To address the majority of the issues, the force was increased in the operation involving the return spring on the valve. For the balance, the test algorithms and limits on upstream test stations were adjusted accordingly to reduce the number of false rejects. The result was that the failure rate was reduced to 0.07 per cent, providing an additional monthly yield of 170 engines. The revenue increase involved in fixing this issue was more than $1 million per month. In addition to the cost savings, worker productivity was increased as the engineer could then focus on other issues with similarly strong returns for his or her time.Looking at the limitsFalse failures and failures downstream in the production process are other common quality and production bottlenecks that can be caused by incorrect limit setting on process monitoring and test systems on the line. Over time, as the manufacturing process stabilizes, adjustments to limits can be made to catch previously unknown problems or to increase production without affecting quality levels.Limits are set by engineering and rarely reviewed, mainly because of the uncertainty and downtime associated with fiddling around with limits. However, limit changes can be fully tested using historical part data before being implemented in live production. Manufacturers can then learn the effect on both yield and quality if limits are tightened or opened.Figure 3 shows a set of signatures for a process, analysed to show a tightening of limits to catch more subtle issues that may have an impact downstream. The red and blue signatures represent the actual data from the production line, with the horizontal line outlining the limits. The signatures in red have adjusted limits, and the software calculates how many more parts would fail if these new limits were applied.Figure 3For example, a fuel-rail leak was detected at a vehicle plant, which slowed production and caused a quarantine situation of thousands of vehicles. All the test data were analysed, and it was discovered that all failures were marginal passes, which meant they had just barely passed the quality tests. In this case, the test limits being used on the test stand were those originally supplied by the part designer and had not been monitored after production startup.The quality manager used one week's worth of manufacturing test data to determine the impact of applying more scientific, statistic-based limits. It was determined that tightening the test limits would have caught the faulty fuel rails with a very minor impact on throughput. Two months' worth of part data were retested, applying the new limits to identify other suspect parts. Three additional suspect parts were found and their serial numbers forwarded to the assembly plant. Production resumed at full speed since confidence in the parts was restored. Not only was this urgent bottleneck addressed, a potential recall situation by customers was averted.Forward-thinking manufacturers who appreciate the impact to their bottom lines have already begun to apply manufacturing intelligence to end the mystery of how quality bottlenecks happen.The good news is that most manufacturers have the beginnings of manufacturing intelligence in their plants. Test and monitoring systems can be the medium through which it all starts. Save and store the data they collect; don't let it go to waste. Manufacturing intelligence software will then bring it to life and provide the analysis tools that will let a quality manager identify the top issues to address, and then drill down as far as needed to fix them. Nathan Sheaff is the founder and chief technology officer of Sciemetric Instruments Inc., based in Ottawa. He founded the company in 1981, the beginning of his pioneering work in the development of signature analysis technology to detect defects in manufacturing and assembly operations. Sheaff is an electrical engineering graduate of the University of Waterloo.
More than a year ago, Nathan Gwinn was suffering from back pain as a result of his job as a press operator at Amber Steel, located west of Toronto in Kitchener, Ont.
Today's wireless technologies can save a manufacturer big bucks if carefully managed, but there are several constraints that have to be addressed if wireless networks are to be successfully implemented in a manufacturing environment. For one, the technology has to work properly, which is not as straightforward as it might seem. Given that the network and devices communicate with each other over the air at the advertised speed and distance, they also have to work with any number of different vendors' wireless devices; they have to be reasonably manageable for deployment, modification or configuration; and they must be secure from intrusion and spoofing. They should be tolerant of changes in the radio frequency (RF) environment, including incidental interference and other environmental changes ranging from weather to a passing freight train traversing a line-of-sight communications path.Another constraint is the fact that there are many wireless standards. The application requirements for distance, bandwidth and power consumption dictate that different standards will be required, but finding what is right for your application is a formidable task. In addition, the technology is rapidly changing. Thus, manufacturers are asking themselves if standards can keep up, and if the rapidly changing technology will make their investment obsolete in two years. Given all of these constraints, why would anyone be jumping into wireless right now? The primary motivation is the potential savings. Cost savingsThe cost of running wires in an industrial environment is very high, ranging from hundreds to a thousand dollars, or more, per foot. So the cost of incremental measurements for fewer dollars is a big motivator. For example, a chemical company needed to profile the temperature of a steam pipe that ran 2,000 metres across the plant to assure no condensation was developing. The layout of the plant would have required that wires for new temperature transmitters be run underground, which required trenching. This is an old plant and EPA requirements mandate that new construction that requires ground breaking examine the soil for contamination. If contamination is found, remediation is required. Having a wireless transmitter not only reduced the cost of attachment, but avoided any requirement to put a shovel into the ground.Even bigger savings are available with new applications that could not have been considered in a wired world, including asset performance management and condition monitoring. Most maintenance in a continuous industry follows a break-fix model - wait for something to break and then fix it. This approach is much less expensive than preventive maintenance, because you are not tossing out working parts simply because the instructions call for maintenance at a particular time. The holy grail of maintenance is model-based predictive maintenance. Based on sensors, typically temperature and vibration, a normal profile can be established. As the profile changes or degrades, maintenance can be scheduled for a time that is convenient for the process and maintenance staff. Dramatic savings are being realized with this technology, but it's only viable with a wireless sensor. If you had to run the wires for all those sensors, the cost would far outweigh the gains. Wireless managementWireless networks require significantly more time and attention than wired networks. The key to success is in the management of wireless networks. Today, most wireless networks are allowed to grow in an ad hoc fashion. A good corporate citizen seizes an opportunity, brings in a vendor, and solves a real problem by purchasing a wireless solution. Another point solution is addressed with another vendor, and a third and a fourth, and so on. Each of these solutions has its own technology, its own access point. Each vendor has its own software for security management, and for network and system management. Imagine a half dozen managers coming into work with routers under their arms, setting up subnet groups for their departments. The management information systems and IT folks would be looking on this less than favourably. It simply would not be allowed.A model needs to be established that, regardless of the state of standards, heterogeneous wireless technologies can be normalized at the access point level (entry into the wired systems). This normalization needs to include a security model that the corporation is comfortable with, and a systems and network management approach that can be managed by plant personnel.Invensys has adopted an architecture that meets these requirements. The architecture supports a single server in the system as a single point of trust for the security model, and the focal point for common wireless systems and security management. Whenever you are dealing with security architecture, there needs to be a single point of responsibility for policy management, otherwise you are likely to either get contention or non-deterministic behaviour when trying to resolve conflicts in how to handle exceptions. The security server addresses critical functions that must be met for all wireless activities. These security and management functions seem to grow exponentially with the increasing numbers of various devices, networks, communication models and vendors. It's only by having a common management of the wireless infrastructure that the situation becomes containable. Security and network management functions must include dynamic network management; fault and escalation policy management; configuration management; accounting/usage management; performance management; security management; device commissioning; and a policy service broker. The policies and standard operating procedures (SOPs) in place for wireless networks must define all methods using, sharing and securing the available bandwidth. This has implications for planning, implementation, operation, maintenance and expansion. For these reasons, wireless networks require a very thoughtful level of construction.Policy management and validation also ties into the end-user's existing IT requirements. The system must be designed to comply with corporate requirements for activities like reporting errors, and observing network behaviours and performance based on that information. It must cover every aspect of the operations, from initial configuration to ongoing optimization. Commissioning and qualification of the wireless network is comparable to commissioning and qualification of any network, but with added emphasis on security and interference. Interference would be addressed first during an RF site survey, which uses scientific tests to measure RF in the plant and in the local area surrounding the plant. Additional security and RF interference testing must also be built into routine maintenance procedures to account for changing internal and external conditions. Performance, availability and utilization are also reporting criteria within systems management, and must be considered as part of an ongoing management program. Policies, such as alarm/alert handling, are part of the system's management function. Policies and SOPs that meet regulatory requirements must also be in place for handling problems. Once the system detects interference, for example, what does it do? Will it reroute traffic, change frequencies or reconfigure antennas to be active or inactive? Some of the options depend on the capabilities of the technology, but within that framework, policy is necessary to guide choices.ImplementationImplementing a management infrastructure requires several months of cross-company planning. Implementation of the technology itself can usually be done in a few weeks. Few companies have the resources to maintain staff necessary for initial implementation, especially because demand for specialists with relevant skills is very high. Outsourcing to one of the emerging specialist firms is currently the most cost-effective strategy for companies that want to enjoy the benefits of wireless networking immediately with little risk. The following checklist can be used to assess your wireless needs and design a system that is consistent with your wireless strategy, policies and quality requirements:Survey the entire company to determine where wireless technologies can best support your business strategy;Create an enterprise-wide policy to control wireless deployment; Design an architecture that will achieve these goals effectively; Conduct an RF site survey to identify potential sources of RF interference and locate wireless communications devices, both internally and external to the plant; Select and purchase hardware and software that is cost-effective, proven and scalable;Develop a prototype in an area with high ROI potential for immediate payback; Integrate to the existing business and operations systems;Measure and evaluate ROI effectiveness of application;Collect lessons learned, measure cost effectiveness of improvements, reassess the strategy, and plan next steps, including additional sites and plants, and global solutions for a rollout; andConduct ongoing monitoring, maintenance, support and optimization services, and incorporate relevant technologies as they emerge.Wireless is here to stay. The technology is capable of enabling many valuable applications across the enterprise. The key to a safe, secure and robust implementation of wireless networks is enterprise-wide planning, co-ordination and management.Hesh Kagan is the director of technology in the Applications, Services and Solutions division of Invensys Process Systems. He is currently co-ordinating the wireless strategy and product development for the Invensys group. Kagan is a founding member and the current president of the Wireless Industrial Networking Alliance (WINA), an organization focused on increasing the adoption of wireless technologies in industry.
Many owners of highly automated systems encounter issues when it comes to the maintenance and support of their legacy equipment. In the world of industrial automation, such issues typically include lost production, difficulty in the acquisition of spare parts, and the need to train staff on these older systems. PLCs, often at the core of an automated system, represent a key concern as they age because of the costs associated with parts and training. But migrating to new PLC platforms involves a great deal of complexity to successfully implement. Allen-Bradley PLC-3s were commonly deployed in control systems right up to the 1990s and, while the PLC-3s are fairly sturdy workhorses, by now it's time for many of these systems to be replaced.An issue with Allen-Bradley PLC-3 migration is that the code cannot readily be converted using automation. Conversion services are available that produce logic that may run on other Allen-Bradley PLCs, but the resultant code requires a great deal of work to debug it and manually create the portions that do not automatically convert. Giffels, a consulting firm that provides control system engineering expertise, has successfully carried out migration projects to upgrade PLC-3s to both PLC-5 and ControlLogix platforms. Recently, two processors at a major automotive manufacturer were converted to PLC-5s, and three PLC-3s at the Liquor Control Board of Ontario (LCBO) were replaced with ControlLogix platforms. The automotive implementation included the addition of two HMI stations for supervisory control, and the LCBO implementation included necessary revisions to code in supervisory computers.Automotive A large automotive manufacture in the greater Toronto area (GTA) uses PLCs to control and monitor its production facilities. The manufacturer was using PLC-3s to control two preparation processes within a paint shop, with a hard-wired panel serving as the main operator interface. The company decided it was time to update its PLCs because it was becoming costly to replace parts. It also wanted to increase the amount of process information available to operators and plant-wide supervisory systems.The switchover was not without challenges. The automaker had a heavy mix of analogue I/O, heavy proportional-integral-derivative (PID) - the logic that is used to maintain a variable at a certain rate - and a high number of PLC-3 rack I/O channels, which required rewiring to suit the fewer available I/O channels in the PLC-5 line. The relatively small footprint to mount replacement hardware, and the few windows available for testing, were additional challenges.The team decided not to employ automated conversion utilities because the heavy degree of analogue code indicated it would not convert well. However, Giffels developed software to automatically generate PLC code for a significant amount of the discrete I/O, thereby reducing human error and debugging time, as well as ensuring consistent code throughout the PLCs. Extensive effort was expended to ensure that all hardware and software conformed to corporate standards, and that personnel at the conversion site and other locations were familiar with the hardware deployed, and with the layout and design of all code.Once the replacement PLCs and HMIs were in place, the old PLC-3s and the operator interface panel were removed. Building on this new system, additional instrumentation was installed and enhanced functionality programmed into the system to improve process control and monitoring. New control schemes were later added to minimize material and energy usage. These improvements reduced raw material costs and improved the final paint quality on the vehicles.Liquor Control Board of Ontario Driven by similar legacy issues, the LCBO's Durham Regional Logistics Facility in Whitby, Ont., initiated a project to replace PLC-3s controlling an extensive conveyance system. Most of the wines and spirits consumed in the GTA are routed through this facility, with tens of thousands of cases shipped to numerous LCBO outlets in the GTA each day. The LCBO turned to Giffels to replace the PLC-3s and a Pyramid Integrator, and to make necessary modifications to a Digital Equipment Corporation (DEC) supervisory computer. Allen-Bradley ControlLogix, using Ethernet and remote I/O communications, was selected as the replacement platform. The project was extensive in scope, ranging from preliminary design through to detailed design, implementation, testing, documentation and training. A staged approach was employed to minimize risk.Many factors had to be considered when designing and implementing the new system. It had to be compatible with the existing operating system, software and hardware, and have the capacity for future expansion. Early stage testing was required to provide simulation of I/O and messaging, as well as normal/abnormal processing conditions. During implementation testing, the system had to include rapid fall-back procedures that would allow users to revert to the old systems. The LCBO also wanted a transparent system so that the revised system looked identical on the users' screens. Other requirements included secure network access to the PLCs; careful attention in the handling of subroutines and indirect addressing, which had been used heavily in the original programming; and extremely high annual uptime requirements. Lastly, the new system had to be something that could be implemented without impacting production throughput.Solution While the PLC-3-based control systems for the LCBO were sophisticated and complex, many of their components stemmed from the 1980s and, as such, significant innovation was required. During the ControlLogix implementation, an intermediate PLC-5 relaying data "packets" was deployed to temporarily bridge legacy software with the latest hardware. In addition, the team deployed designs that avoided "re-addressing" I/O. As a result, the LCBO did not have to be concerned about changes to the labelling of field devices and wiring. The PLC-5 was configured with proxy files to mimic the PLC-3 data structures, and it served to translate the PCCC format - the old Allen-Bradley communication protocol - to the latest CIP protocol, and vice versa. An extensive data packet communication scheme was required for positive verification of data arrival at final destination. Coding within the DEC OpenVMS machine (in c language) was approached in such a way as to minimize changes and risk. PLC addresses in existing code were re-directed to and from PLC-5 locations, making changes transparent to the calling routines, which had initiated communication to the PLCs. Giffels used hardware to permit live switching of I/O, enabling rapid switching to and from the new platform for testing purposes. The team also created code to emulate obsolete program calls. They used automation, where possible, for generating code and for transferring data between old and new systems, thereby providing the highest levels of accuracy.The LCBO has since upgraded the supervisory computer to be compatible with ControlLogix, and the PLC-5 will soon be eliminated.Results In both applications, Giffels developed detailed plans and worked extensively to deliver solutions that met the automaker's and the LCBO's implementation requirements, as well as their cost, operational efficiency and reliability objectives.There was no negative impact on production. Each facility operated, uninterrupted, on a five-day, 24-hour basis during implementation. Since the migration, key benefits include the provision of additional process data and alarm conditions to operators, and increased availability of process data to supervisory systems for reporting and historical analysis purposes. The team was able to preserve functionality, including interaction with controlling/indicating I/O, operator interfaces and related computer systems, thereby providing smooth, reliable operation of the systems. The team also provided improved, secure access to the PLCs using commercial, off-the-shelf technology, facilitating more rapid and mobile system troubleshooting by support personnel. The clients now have an enhanced programming and troubleshooting environment in the RSLogix programming suite, which they use to carry out further optimization and to improve throughput.For both the automaker and the LCBO, maintenance, spare parts and downtime costs have been reduced by eliminating the need for expensive, obsolete hardware. As well, a platform has been provided in each case that is consistent with each company's long-term migration plans. Additional benefits are found in the enhanced development and troubleshooting environment provided by more powerful development software, and in the elimination of the need to maintain specially trained skill sets associated with the older PLC-3 and Pyramid Integrator platforms.Michael Codrington is a senior engineer, control systems, with Giffels Associates Limited, based in Toronto.
Industrial robots guided by machine vision have the potential to revolutionize manufacturing processes, improving repeatability, cycle rate, reliability and safety on the plant floor, while reducing costs associated with labour and fixturing. A lack of understanding and awareness of the technology's value has, in the past, hindered adoption. However, as competitive pressures increase, hardware and software costs decrease, and technologies improve, manufacturers in many industries are exploring the possible implementation of vision-guided robotics (VGR) to improve productivity and competitiveness.To help you decide if the technology is appropriate for your manufacturing environment, we've asked five experts in the vision-guided robotics arena to discuss the benefits, challenges, integration issues, major breakthroughs and appropriate applications for the technology in manufacturing. The participants are Edward Roney, development manager, Product Development Division, Fanuc Robotics America, Inc.; Ken McLaughlin, director, flexible manufacturing, JMP Engineering; Gordon Deans, vice-president, business development, and general manager, Adept Canada; Bryan Boatner, product marketing manager, In-Sight vision sensors, Cognex; and Babak Habibi, president, Braintech. For more information on our panelists, see "The participants" on page 19. BenefitsAsk anyone in the vision-guided robotics arena about the technology, and they can provide you with a laundry list of benefits. "VGR is capable of effecting a major paradigm shift in manufacturing," says Habibi. "Elimination of hard tooling and fixturing is one of the principal effects that can result in significantly lower capital and maintenance costs for manufacturing. Couple that with the fact that with vision guidance, robots can be deployed increasingly in places where robotic automation was not imaginable before, and you can see that this has a powerful effect on the landscape of manufacturing and the way we will lay out our plants of the future." Other major benefits, says Habibi, are reductions in labour costs, as previously manual applications become robotizable because of VGR, and increased asset utilization due to the ability to run multiple part styles down the same production line.McLaughlin agrees that cost savings are a major plus. "Manufacturers can benefit from labour cost reduction through the automation of tasks that were previously not possible, and often ergonomically challenging."ChallengesEven with the plethora of pluses, experts are quick to caution potential adopters about the many factors to consider for successful implementation, including lighting, location, training and integration challenges. But the panelists agree that successful implementation and integration start with proper planning. Says Roney, "The first major challenge is the selection of the vision supplier. There can be some significant challenges facing an integrator or end-user depending on whether the vision product is already integrated as a standard product of the robot, or if the use of a general-purpose vision system supplied by another company other than the robot manufacturer is to be applied. In using a general-purpose vision system, several challenges immediately exist, [including] communication - how will the vision system and robot exchange information; precision calibration - the matching of the vision image to the robot co-ordinate systems; and robot math - making the vision data useful to the robot and using co-ordinate frames). These integration concerns can be large engineering tasks that can be eliminated if the end-user specifies the use of a vision system designed as a standard integrated product - an application-specific solution. With a standard product, all the issues listed above have been addressed and designed into the complete intelligent robot package, which then lowers costs, reduces risk and provides a more supportable automation solution."McLaughlin explains that often the biggest challenges are associated with the physical constraints of the system. For example, he says, "in vision-guided bin-picking applications, the vision system may be able to easily identify that a part is upside down or on its side, however, the robot gripper needs to be able to deal with this. This means the gripper must be designed to handle parts in multiple orientations. Another common scenario is if a part is leaning up against the side of the bin and the robot can't pick it because the robot itself will collide with the side of the bin. [The] bottom line [is], in a vision-guidance application you need to consider the entire system - vision system, robot reach, robot gripper, multiple orientations of parts, etc. - in order to design a system that will be successful."According to Deans, before implementation, manufacturers must consider logistics, such as where the system will go and who will operate it. Financial issues, such as cost, also need to be reviewed, as do practical issues, such as upkeep, maintenance and training. And once you know that, control of the environment is the single largest factor to consider, he says, adding that lighting and the appearance of the parts are a major part of that. "Lighting, of course, is subject to changes in ambient light, including overhead lights, sunlight through windows, reflections from adjacent equipment, as well as variations of structured lighting intensity over time," explains Deans. "The appearance of the parts is subject to variations in manufacturing which may affect the colour or surface finish of the parts, as well as the amount of particulate mixed in with the parts." He adds that conveyor tracking or an equivalent consideration of moving objects requires "tight timing and latency control between the robot controller, various sensors that detect conveyor movement and speed, and the object detection in the vision system." Deans says that environments with abrasives or chemicals that are airborne are also a challenge, which can be overcome with the use of sealed enclosures and proper venting. Stamping or press machines that induce major vibrations are also an ongoing challenge that must be considered at the system design stage.Boatner explains the challenges from both the 2D and 3D side. "It is important when evaluating a potential VGR application to determine whether you need 2D data (x, y, theta), 3D data (x, y, z, yaw, pitch, roll) or something in between. That being said, for 2D and 3D applications, one of the biggest challenges in VGR is that ambient light may play an unexpected role. Changing light conditions cause nearly every image of the part to vary slightly due to shadows that shift around on the part as its position with respect to the light source changes...A second challenge is setting up communications between the vision system and the robot...For 3D applications, in addition to the challenges stated above, often times the user needs to calibrate two or more cameras to each other, which is complex and requires significant vision and robot expertise." One of the technology's major benefits is also one of its major challenges, explains Habibi. "One of the key advantages to vision-guided robots over their blind cousins is that they don't need the workpiece to be in the same position or even of the same type before it can be operated on. A blind robot relies on fixturing to pre-position the part at the pre-trained position, whereas a vision-guided robot locates each part every time. The fact that part position, orientation and type can change means that unlike vision inspection systems, where the part is typically fixtured or its movement heavily restricted, VGR systems can't depend on a convenient placement of cameras and lights to obtain an ideal image."In order to overcome any integration issues, McLaughlin says that the proper training of plant personnel is key to a successful integration and adoption. "There is often a perception that vision guidance is black magic and, as such, people are often afraid and distrustful of it. By training plant staff thoroughly when the system is deployed, they understand it and are able to support it."AdvancementsLike fine wine, vision-guided robotics is getting better with age, and recent breakthroughs in the technology have improved VGR performance on the plant floor. Says Roney, "Vision systems are a quarter of the cost they were just 10 years ago, and with the higher levels of integration into the robot controller, the cost of implementation has been significantly reduced. Advanced reliability has also increased the adoption of vision-guided robotics. Vision tools like geometric pattern matching, where the features of an object are identified and matched instead of a pixel comparison, have significantly added to the reliability of machine vision for robotics. For industrial robots that work in manufacturing plants that make parts or products from raw materials or in-process goods, this reliability has greatly increased the applicability of machine vision and reduced the maintenance concerns that were once associated with previous systems that were tremendously light change sensitive."Habibi says that there have been several breakthroughs in the area of algorithm development. "I can point to at least three new pose calculation algorithms we have developed in the last three years, which are aimed at locating various types of objects with various geometries and appearances. As more of these techniques come online, a larger variety of workpieces or parts can be located and the information can be used for robot guidance. The ever-multiplying speed of PCs and introduction of dual and recently quad core processors in the last few years is certainly notable as it makes execution of advanced algorithms feasible by allowing them to run within industrially acceptable cycle times." According to McLaughlin, "Vision systems and tools have become dramatically more robust in the past few years and have really made vision a stable, solid technology to use in the manufacturing environment...As well, the proliferation of Ethernet communication now allows for the transfer of large amounts of data easily between the vision system and robot.""Improvements in industrial lighting solutions are a major breakthrough," says Deans. "High-intensity LED lighting, directional lighting and more robust lighting solutions have helped immensely. Also, the increase in the computing power of vision systems has improved vision system performance and speed. Processing power, resolution and the packaging of cameras is a major improvement. In particular, digital cameras have greatly simplified the vision interface." Low-hanging fruitWith these advancements comes increased adoption. The panelists say that, if implemented and integrated correctly, vision-guided robotics can be used in almost any process in many industries, but there are certain industries and applications more suited to the technology than others, and certain applications that are less challenging than others. "Industries of all types are embracing vision-guided robots," says Roney. "The automotive industry is using guidance for the assembly and processing of engine and body components. The food industry is using vision-guided robotics to pick products from conveyors for packaging into individual containers or cartons. The pharmaceutical industry is using vision and robots to locate medical supplies on moving belts for packing into shipping cartons. Metalworking industries are finding metal castings on pallets and loading CNC machines to make finished component products...And yes, we are even using robotic guidance in bin-picking applications today that just a few years ago was thought to be impossible." "Material handling is the low-hanging fruit that this technology can be used to capitalize on today," says McLaughlin. "Typical [2D] applications [are] picking from a stationary or moving conveyor...Typical applications for 3D vision guidance are bin-picking applications. We are also seeing interest for robotic deburring and material removal applications where the robot uses the vision system to locate the part before starting to deburr the part."McLaughlin says that the automotive industry in particular has embraced the technology because of pressure from low-cost overseas manufacturers. "Automotive programs have lower volumes and shorter lifespans. As such, there is a trend away from special purpose equipment designed to run a single part towards flexible equipment that can run multiple parts or programs simultaneously. For example, instead of using a traditional fixtured conveyor to deliver parts to a cell, a manufacturer can now use a standard, off-the-shelf, flat-belt conveyor and a vision-guided robot to pick the parts from the end of the conveyor. Not only is the initial capital cost less, the system can now run multiple parts simultaneously simply through programming changes to the vision system and robot."Deans says that packaging applications are ideal because of the requirement for picking randomly ordered objects from moving belts. Other suitable applications include high-speed parts processing, and complex mechanical and electrical assemblies. "Bin-picking technologies are advancing, but not yet mature," he adds. According to Habibi, the technology is suited for applications where, in the past, a part needed to be fixtured to enable the robot to perform an operation on it, or cases where a robot could not be deployed because fixturing was not feasible, such as the removal of parts from bins, parts assembly, sealing and adhesive dispensing. "Generally, with the technology available today, we can locate most rigid objects that have a handful of visually discernable features such as edges [and] holes," he says. "Each application," Habibi continues, "requires a degree of specific engineering and therefore you naturally see system integrators focus their attention on high-volume applications where they can amortize this cost over a large number of systems. In other words, even though a lot of applications may be solvable today from a pure VGR technology point of view, integrators may postpone offering affordable commercial solutions to these in the short- to medium-term while they exploit the low-hanging fruit."Boatner has seen an increase in adoption across the automotive, food and beverage, and packaging industries. But, he says, "The fastest growing applications in the 2D VGR market include automated palletizing and depalletizing, conveyor tracking, and component assembly. In the 3D market, applications for auto-racking and bin-picking are showing healthy growth...Unlike using blind robots, vision-guided robots don't depend on costly precision fixtures to hold parts, require additional labour to load and orient parts, or need upstream actuators, sorters and feeders to separate parts for processing. Consequently, VGR enables manufacturers to more easily process various part types without tooling changeover. Plus, VGR provides the added benefit of automatic collision avoidance for safer work cells."Are there any applications for which the technology is not appropriate? "There are not really any bad applications, just systems that are applied badly," says Roney. "If a robot application is identified as a vision-guided opportunity, and the system is either miss-specified or incorrectly engineered, then it becomes a bad application."According to Boatner, "With the right expertise, robots and vision can improve the effectiveness and efficiency of nearly every factory floor operation."But Habibi says that flexible or floppy objects can be more challenging to locate, although individual points of interest can be located reliably. Applications in extreme environments where there is a great deal of debris, high temperature or humidity are also difficult because of camera and lighting line of sight contamination, he says.What's the ROI?So you've weighed the benefits, considered the challenges and narrowed down possible applications. Next you have to calculate whether you will receive an ROI in a suitable timeframe. Here are some things to consider:"ROI calculations include the obvious cost of the system versus increased production and labour savings," explains Deans, "but [manufacturers] often overlook important issues such as reduced rate of scrapped parts and customer satisfaction due to improved repeatability in the product."According to Habibi, when assessing possible ROI, manufacturers must consider a number of factors: "How much do you spend on fixturing of parts or specialized containers to make sure parts are pre-positioned for robots? What would be the savings if they could be eliminated or simplified? Are there labour-intensive, high ergonomic injury processes in your operation that could not be automated in the past due to infeasibility of fixturing? What would be the savings if they could be robotized? Are you getting enough out of the capital equipment investment you have in place now? How much more productivity could you achieve if you could run one, two, three other part styles down the same line? Our analysis shows that in the majority of cases, ROI for typical VGR systems is close to [six months]. In many cases, there is instant ROI when an expensive fixturing or positioning device can be eliminated from the list of capital equipment." "Bin-picking is an easy application to calculate the ROI as it is a direct, tangible labour savings," says McLaughlin. "JMP has implemented several VGR bin-picking applications where the ROI is less than one year."Expert adviceIn closing, each participant was asked to offer advice to those considering implementing a vision-guided robot system. Here's what they said:Roney: "Understand where the application success lies. Is it in the vision system, the robot application or both? Consider support from the company you are purchasing your system from. How much support can they really supply and for how long? If you are buying the vision system and the robot separately, who then will be responsible for the overall success of the vision-guided robotic solution? Also, ask your supplier if classes are available, not just for the vision system or the robot, but on vision-guided robotics where vision and robots are taught together, working together. It is important to remember that in vision-guided robotics, one does not work without the other. You must understand both."McLaughlin: "Work with an experienced, certified integrator that has done this before. This mitigates your risk and ensures you get a system that is reliable and robust. Also, keep it simple; use a combination of vision technology and mechanical compliance to solve orientation and reach issues. Test, test and test it again; make sure every scenario is tested and validated to avoid hiccups when installed in the plant."Deans: "An important first step is to develop an idea of what the system needs to do, as well as what you would like it to do. This includes a determination of how material will flow in and out, as well as what processes will be performed by the system, and how workers will interact with it. Next, consulting with an experienced partner (i.e. the integrator or robot company) is essential, as they can steer you towards solutions that have worked in the past. We also believe that one should look for vendors with well-integrated solutions, not just piece parts, to reduce risk in the system integration and post-installation service. Finally, complete buy-in from the end-user is important." Boatner: "The first thing to do is to consult an integrator that has substantive experience integrating vision and robots. Their experience will be invaluable as you implement your VGR application. It is recommended that a detailed failure mode analysis be performed so that if a problem does occur, an action plan has been identified to limit the downtime of the robot...Make sure to buy vision software with an advanced part finding algorithm, an easy-to-use software development environment, and [one] that includes communications drivers and sample code. It's also a good idea to purchase a package that has a complete vision toolset...especially if there's a chance that the vision guidance application will be expanded to include code reading, part gauging or other vision tasks. Finally, be sure that the vision hardware comes standard with cables that are rated to at least 10 million cycles."Habibi: "Examine your ROI picture carefully to see where you can realize the most savings...If you are new to VGR, try to find applications in your plant that are already proven elsewhere in the industry to get you familiar with the technology, its strengths and its limitations. Pick a well-known integrator that can provide you with a standard, engineered VGR system targeted at solving these specific applications. Later on, when you are more familiar with the technology, you will be able to extrapolate the capability to other applications with much less risk."The participantsEdward RoneyEdward Roney is the development manager for the Product Development Division of Fanuc Robotics America, Inc., a supplier of industrial robots and factory automation systems. He is responsible for the development of global machine vision products for use in Fanuc's line of intelligent robots. Roney has been active in the application of machine vision technology since 1982 and is currently serving on the Automated Imaging Association board of directors.Ken McLaughlinKen McLaughlin is the director of flexible manufacturing at JMP Engineering, a London, Ont.-based industrial system integration company that specializes in the engineering and provision of automation, control and information solutions. He has been with JMP Engineering for eight years. McLaughlin is responsible for JMP's turnkey material handling systems for automotive, food and beverage, and pharmaceutical applications.Gordon DeansGordon Deans is vice-president of business development and general manager of Adept Canada, a manufacturer and marketer of robotics, vision and motion control products for automated material handling and assembly. He was previously the president of Telere Technologies Inc., a consulting firm providing product marketing and business development services to high-technology organizations. He holds a bachelor of science and masters degree in electrical engineering.Bryan BoatnerBryan Boatner is the product marketing manager for In-Sight vision sensors at Cognex, a supplier of machine vision sensors and systems. He holds a bachelor of science in mechanical engineering, and held application-engineering positions at Cognex from 2000 to 2005.Babak Habibi Babak Habibi is the president of Braintech, a North Vancouver, B.C.-based company that designs, develops and deploys software for vision-guided robotics systems. He completed his bachelor of science and masters degrees at the University of Waterloo in Waterloo, Ont. What is vision-guided robotics? • When a camera or sensor is used to provide positional information to a robot so that path is changed to adapt to the real position of the workpiece or part being processed by the robot. Vision is used to determine that new position and hence guide the robot. - Edward Roney• The use of vision technology to locate an object and/or feature(s) on an object in space and update the robot path to perform the desired operation on the object. - Ken McLaughlin• VGR uses digital imaging and intelligent software to add the ability to see, comprehend and reason to traditional blind robots. Vision-guided robots take advantage of cameras and intelligent software to give robots information about their environment, including 3D location, orientation and type of parts; type and quality of attributes and features on parts; and relationship between parts, robots and other objects. They react in real time to type, quality and position of objects in their workspace. - Babak Habibi• A vision guided robot system is one where machine vision and robot control are tightly coupled to locate randomly oriented objects in the field of view of the camera(s) and generate robot movement to act on the objects. - Gordon Deans
The thought ran through Frank Haran's mind more than once–"We're breaking a whole lot of rules."
It's survival of the fittest for manufacturers these days. Those who remain lean and implement leading-edge technologies and flexible processes to produce high-quality products cheaper and faster than their competitors will be successful. To help you achieve success, we've asked industry experts to name the top five technologies or trends they think will make a difference in 2007 and beyond. Thank you to Jim Pinto, Peter Luh, Peter Orban, Sal Spada and Sath Rao for contributing to our second annual Top 5 feature. Last year, wireless technologies and robotics were a common theme among contributors. This year, wireless and robotics still made the list, along with a bevy of other emerging technologies. Read on to see what the experts had to say.
When Bill Valedis teaches safety courses, he often tells the story of when he took flying lessons. During one flight, he had the procedures manual between his legs but clearly hadn't properly studied it. After that session, the instructor told Valedis she would never fly with him again. She had put her life in his hands, and he hadn't followed proper procedures. Flying a plane unprepared is a bit like running a company with a safety program that just sits in a binder and collects dust, or being only vaguely aware of machine guarding requirements.Valedis is the president of Imperial Automation Technologies Inc., based in Fergus, Ont. He conducts training in pre-start health and safety reviews (PSRs) and has learned, by the questions people ask him, that many manufacturers are unaware of their legal requirements for machine safeguarding. Valedis urges them to learn and to understand that codes, standards and regulations are designed to minimize risk."When guys grumble about procedures, saying it's a bunch of bull and pieces of paper, I say, 'No, it's not. It may not be perfect, but we must understand that they exist, what they do, and we must follow them.' "In other words, legislation can only take us so far. Taking the time to understand and apply it is everyone's responsibility. Just like himself when he was eager to fly but impatient about taking the proper steps, Valedis says companies that neglect their requirements may be putting people's lives at risk."We all get buried in having to make production, keeping the bottom line rolling and the product going out the door, but we could all be sitting in a room one day and say, 'Why did this person die?' " says Valedis. "Having sat through department of labour hearings and testified as an expert witness before, I've left all these sessions with a gut-wrenching feeling in my stomach: Why aren't we doing enough?"Safeguarding requirementsBill C45 imposes a legal duty on all employers to take measures to protect employee and public safety. There are also regulations for industrial establishments in every jurisdiction's Occupational Health and Safety Act, and manufacturers must comply with any applicable standards that are referenced in the legislation. These may include the Canadian Standards Association's Code for Punch Press, Z142-02, Guarding of Robots, Z434-03, and Guarding of Machinery, Z432-04, depending on the type of machinery in your plant. When any new piece of equipment is commissioned or started up, the law may require a pre-start health and safety review, depending on the legal jurisdiction and whether or not exemptions apply. In Ontario, this requirement came into effect in 2000 but continues to baffle some employers. Franco Tomei, guarding specialist with the Industrial Accident Prevention Association (IAPA), gives clients ideas and options to help them comply with safety law. He says that many manufacturers struggle to understand the requirements for safeguarding, especially when the regulations are performance based as opposed to outcome based."The question manufacturers often ask is how to comply," says Tomei. He says that employers voice frustrations with the requirements, and that they are often not sure how far to go in compliance, and where to draw the line. While the primary objective of machine guarding is to prevent access to the point of operation or exposed moving part, "the reality is that no matter how far you go, there's always somebody who will find a way to gain access," says Tomei. "Often, when I do point out an access point that is to be safeguarded, there is the stunned expression: 'Nobody in their right mind would go in there.' I have to explain that they are absolutely correct, but that the Act and regulations were not intended for those in their right mind."Nonetheless, even wise, safety-minded employees sometimes get hurt if they don't have adequate safety training. Another objection Tomei hears from employers is that they have responsible, experienced employees who have never had an accident. Experience, however, isn't the same as knowing the hazards and regulatory requirements of a job. In the same vein, a perfect safety record to date "does not in itself constitute safe conditions and is a flawed conclusion," says Tomei.Mike Voll, controls manager, Manufacturing and Industrial, with Stantec Consulting Ltd., sits on a number of CSA committees. He says the committees continually go over the grey areas that companies have trouble understanding. In creating the standards, he says, "They try to have as little impact on the manufacturers as possible, but there has been a huge impact on manufacturing. When the standards first came out, I think the general view in industry was 'We'll only do it if we have to,' because it's costly."But it is improving your safety level, and potentially reducing your compensation claims, which ultimately could be improving your bottom line. And if you're fined by the government," he adds, "that will impact your productivity as well."As employers get to know the regulations and codes that apply to their workplace, they should never forget one simple and essential requirement of occupational health and safety law: due diligence. At the most basic level, the law wants proof that employers, supervisors and workers are doing whatever they must to ensure everyone's safety on the plant floor. Keeping that in mind, hereÃs what the law expects of employers:1. The risk assessment Conducting a risk assessment is the first thing Voll recommends for anyone considering a safeguarding upgrade. The purpose of this step is to analyse all hazards in the regular operation of the machine, and in setup or changeover functions. Guidelines recommend that the risk assessment be conducted or orchestrated by the professional engineer who's doing the pre-start health and safety review (if applicable), but Voll says this step should involve all stakeholders, including the equipment manufacturer, operations people, maintenance staff, operators, and health and safety groups within the organization. "What you're essentially doing is agreeing on the level of risk of each of the devices on the system," he says.The risk assessment explores these and other questions: How does the operator interact with the machine? What are the potential hazards? What's the frequency of the operator's exposure to those hazards? What's the likelihood that something could happen? If something could happen, how severe would it be? Could the operator lose a finger? Could he lose an arm? Is it just a scrape? Is it something that can be treated with first-aid? Is it something that's reversible?One process and one hazard at a time, conducting a risk assessment gives employers a better understanding of their safety requirements. It might also confirm the need to conduct a pre-start health and safety review.2. The pre-start health and safety review This process analyses the safety of each machine or process before it is installed or modified. According to safety regulations, only a registered engineer may conduct the review. Voll, who performs PSRs for various clients, recommends engaging the expert sooner than later, ideally at the machine design stage. "If the reviewer is not involved early in the process, it can be extremely costly," he says. "We'll end up doing the review on a set of electrical drawings, let's say, for a machine that's already being built, and we'll find a whole series of non-compliances that will effectively flag a redesign. If it had been done earlier it would have saved a lot of money and re-work."Tomei agrees, saying employers are often shocked to find out that the brand new machine they just bought is not in compliance with safeguarding codes."If an unsafe machine is allowed to enter the workplace, it will become an albatross to all those who come into contact with it over its life," he says. "Safeguarding is best integrated at the design stage and not with retrofits."Too often, Tomei has seen employers take corrective action rather than more prudent preventive action. He says that's like paying for a deficient product, paying somebody else (an engineer) to identify those deficiencies, and then paying yet again to have someone else correct the identified deficiencies."I am often shown the approval sticker on machines placed by an authority that has assessed compliance with the electrical code," says Tomei. "And I must point out that this is only for [the] electrical aspect of the machine. It does not indicate compliance with safeguarding requirements."When buying new equipment, Valedis recommends that employers spell out their guarding requirements, in writing, to equipment suppliers."As an employer you'd better have, in your purchasing agreement, requirements for compliance. If an accident occurs, the Ministry of Labour will step in and say, 'Okay, it involves this machine. Who is the manufacturer? Is the machine manufactured to some international standards? What are these standards?'"They'll do an investigation on you, and as soon as they find out by looking at your purchase order that you don't even specify what regulation XYZ means and how the manufacturer of this machine must comply with your requirement, well you've shown the Ministry or any investigator that you really don't have a safety plan." 3. Equipment installation or upgrade Once the risk assessment and PSR have been conducted by qualified experts, it is safe to proceed with the new or upgraded equipment and processes. That doesn't mean forgetting all about safeguarding, however. See the sidebar, Safeguarding compliance, for after-implementation compliance tips. 4. Proof of due diligence - safety records and reports The law requires that companies have all safety documentation on hand. During a safety audit, or in the event that an employer, supervisor or worker must defend himself or herself in a libel suit, safety records and reports will demonstrate that they have practised due diligence and understand their responsibilities.5. Communication and training Employees, too, are responsible for safety. They must adhere to safeguarding requirements by always using the safeguards that are in place and following established procedures. That means employers must communicate those procedures to employees and provide the necessary training. And rather than just relying on the generic training by some equipment providers, Valedis says it's important to find a trainer who takes the time to truly understand the company's particular tasks, processes and hazards.Safety is worth the timeWhen Valedis goes into a plant where technical staff are well trained in safeguarding and other safety requirements, he senses a certain level of satisfaction, elevated knowledge and less anxiety. "Sometimes these are very intangible things to put a dollar value on," he says. "Safety is expensive, but it produces results because it informs the people in how to conduct their duties and responsibilities with a lot of confidence. And if you have confidence in what you're doing, you'll do it safer and be more productive because you'll do it in less time."For additional information on machine safeguarding, which standards you may need to comply with, and a list of circumstances that trigger a pre-start health and safety review, visit www.labour.gov.on.ca, www.csa.ca and www.iapa.ca.Michelle Morra is a Toronto-based freelance journalist. Safeguarding compliance: After implementationSo you've assessed safeguarding risks in your plant, conducted a pre-start health and safety review, and gone ahead with the necessary equipment changes and upgrades. If you've done your homework, your new and improved processes will be not only safer, but they will also be flexible. Expect to make updates or corrections because situations on the plant floor will change.Manufacturers' responsibilities do not end after implementation. Your Ministry of Labour or safe workplace association are available to help, but remember these tips for starters:• Control access to the machine or equipment. Even after a safeguarding measure is in place, you must provide further protection in the event that someone might not use those machine guards. "This is an elaborate procedure that states if you are going to bypass a safety device, which is undesirable by every stretch of the imagination but necessary in the world we live in today with the complexity of machines and processes, you must follow this energy control procedure," says Bill Valedis of Imperial Automation Technologies. "There are stipulations. There is flagging of the particular equipment. There is extra perimeter guarding that goes onÃ– Procedures as to exactly how to prepare the space or the machine before you enter, and a whole host of steps that the employee must follow."• When a machine breaks down, be thorough in your corrections. Franco Tomei, guarding specialist with the Industrial Accident Prevention Association, says when machines are placed back into production after a breakdown, problems sometimes arise. In some cases, he says, the safeguarding will be replaced later as a result of production requirements. "Too often the safeguards are never really replaced, eventually misplaced and never to be seen again," he says. "Maintenance personnel must, for their own protection, ensure that the repair of the machine is not finished until all aspects (including safeguarding) have been replaced and [are] functioning within specifications."• Encourage employee feedback. As impressive as your safeguarding processes might be, only the employees who use those processes can truly determine how well they work. So talk to them. Give them a means to exchange ideas, and ask them questions such as, "Is there anything about this procedure that we need to modify? Have we run into any difficulty with changing a tool, for example?"Valedis says, "We need to have a system that updates the information. It must be easy, and it must not be bureaucratic or take 16,000 pages of paper to fill out."• Conduct periodic safety audits. Your engineering staff, and perhaps a member of your safety team, should periodically target each area and investigate how things are really working. They should find out how a process works, whether staff are following safeguarding procedures, note any deficiencies and correct them. Valedis says these audits are a logical part of a companyÃs quality assurance program.Complying with safeguarding requirements, communicating them to employees, and doing the necessary followup and maintenance will make a world of difference in your organization. Investing the time and money for safety will likely make your company prosper more in the long run, both financially and in terms of protecting your workersÃ limbs and lives.
When robots first came on the manufacturing scene in the late 1950s and early 1960s, skeptics accused them of stealing jobs and dehumanizing the workplace. Others thought robots could solve the industrial world's woes. Today's truth: We've only just begun to realize the robot's true potential.
Over the last few years, the development of electric linear actuators has led to their increasing use in linear motion systems that would have previously used hydraulics. As a result, it is now good practice before designing a new linear motion system to decide which type of linear actuator is best for the system–electro-mechanical actuators or hydraulic.
Taking the guesswork out of assembly accuracy can have benefits well beyond cutting costs. When Ford Motor Company implemented a 3D vision system at its engine plant in Windsor, Ont., the automaker increased assembly accuracy in nut-running, reduced rework time, reduced downtime and increased efficiencies. But arguably the biggest benefit the auto giant has seen since implementing the vision system is zero incidences of engine failure associated with loose bolts. Ford manufacturers 3,600 engines at its 1.2-million-sq.-ft. engine plant each day. For a company that measures success by quality, just one faulty engine could result in the loss of business."Quality means so much in this competitive industry," says Sara Stojcevski, a fastener engineer with Ford.Previously, the company relied on PLC alerts to detect misapplied bolts on the engine mounting line. When a problem was detected, engines were diverted to a repair bay where technicians would manually unfasten and re-fasten all 16 bolts on the V-8 engine, even if only one bolt was loose. The system had to acknowledge 16 hits before releasing the engine. But this process was unreliable, ineffective and time consuming. "The problem with that is you can hit the same bolt 16 times and get an okay torque and [release the engine], but there could be 15 other bolts that are loose," says Stojcevski. "That resulted in our customers receiving engines with loose connecting rod boltsÃ–Sometimes they caught it at our vehicle operations plant, but we've also had many get right to our customer."The plant needed a solution that would pinpoint which bolt needed to be fastened and confirm that it was, in fact, fastened, eliminating any unnecessary unfastening and refastening of bolts that were already tight. Stojcevski contacted Ross Rawlings, president of Oldcastle, Ont.-based Radix Controls, and Nikola Dimitrov, the companyÃs vice-president of engineering, to come up with a solution. The team tested various types of systems, including an ultrasound system and an ultrasound system in combination with an inertial navigation system, but neither was reliable enough for Ford's application because of the excessive noise associated with manufacturing environments. Finally, it was decided that a vision system was the appropriate solution because the technician needed to see that the proper bolt was being torqued down. Enter Tool Tracker, a 3D vision system developed by Radix Controls. The system had been in development for two years before being implemented at Ford.How it worksThe Tool Tracker is an integrated system for visually tracking and identifying the location and orientation of an object within a given space. It uses a target, one or more cameras and subsequent analysis within the mathematical model in the system software. The system also includes industrial computers to analyse the images, and a graphical user interface that provides operator feedback that the operation was completed. Using a strategically placed camera, Tool Tracker validates that the operator with the torque gun is doing the correction at the right place, and that it has been executed as required. The tool uses high-speed visual tracking technology to track a target permanently mounted on the hand tool (in FordÃs case, a torque gun). It tracks the target and reports the toolÃs socket position. That information can be used to determine if the correct nut has been fastened. The system links with process data, validates the position and corresponding torque event for quality programs, determines the number and position of bolts that have been tightened, and verifies results to the operator, who then releases the engine. Implementation and benefits The installation took two weeks, and included mounting the Atlas Copco PowerMacs controller stand and the fastening tools bracket; making modifications to the existing engine rotate so the team could locate the engine; programming the PowerMacs controllers; electrical wiring and piping; calibrating the camera; teaching the bolt locations; interfacing the Tool Tracker HMI with the repair bay PLC (a Modicon 984); and error-proofing the repair bay PLC logic. Once everything was in place, the team needed a couple of days to configure the application.The Tool Tracker is currently implemented in one repair bay at Ford's engine plant, but Stojcevski says that there are other areas of opportunity that the company is looking into. She says the system could be implemented anywhere on the floor where error-proofing is required. "We have shared this technology with our technological department within Ford, and they are extremely impressed," she says. "They are thinking of buying the product and using it in other areas of Ford."It's been almost a year since implementation, and the team is happy with the results. The system has reduced rework time by as much as 80 per cent and, because the technicians are doing fewer steps, it has allowed them to work faster, churning more engines out of the repair bay than ever before. "We'd get instances where they were so busy in that bay, because our repair bay only holds so many engines. Once it fills up, the line will stop," explains Stojcevski. "Because they'd have to do 16 hits before they can release anything, if there was any sort of quality issue with engines that were coming in, we would stop the line because [the technician] couldnÃt do it fast enough. So now with this, itÃs more efficient. Very rarely do we get backed up to the point of stopping the line. Actually, I donÃt even think we've had that issue." The Tool Tracker also automated the error-proofing aspect of the repair bay. Previously, the error-proofing technique was to have the lead supervisor verify that the engine had 16 hits. But the lead supervisor was responsible for the entire line, and was not always available, so they would have to wait. The Tool Tracker has automated that part of the job, and frees up the lead supervisor to do other things. The system also provides traceability, since it collects historical data. If there is a recall, production records could be scrutinized rather than the vehicles, resulting in a reduction of the number of vehicles brought back for examination, which will save money. There are additional impacts on the bottom line. Stojcevski says that the automaker quantifies its engine exchange due to loose bolt failures at about $5,000 an engine if they have to exchange the engine. She estimates that the company has saved $150,000 by implementing a system that ensures that engines with loose bolts do not leave the repair bay, and thus never have to be exchanged. "But the biggest savings," she says, "is our customer satisfaction. We can't put dollars to it, but it's a big deal to us. "When this system is in use, and used properly, 100 per cent of engines have now been good engines. I havenÃt seen any loose rod bolts come back like we did in the past," she says. "So as you can see, our quality depends on this system."TOOL TRACKER AT A GLANCEWhat it does: The Tool Tracker links with process data; validates position and corresponding torque for quality control programs; determines the number and position of bolts that have been tightened; and verifies results to the operator. Features: The Tool Tracker can track with one or more cameras; it can track multiple targets simultaneously; it has static repeatability of one millimetre - how close several measurements are if the target is not moved; dimensional accuracy of one millimetre - the quality of the measurement obtained; it supports multiple resolutions; and it uses standard protocols.Applications: Industrial (tracking exact placement of large machinery); automotive (accuracy and verification of assembly operation); packaging (automating pickup and placement of shipping boxes); and aerospace (docking applications).
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