Come Together

New Mechatronics Tools Make It Easier for Engineers to Collaborate on Model-Based, Motion-Enabled Designs

By Jim Montague

October 2009"Mechatronics" probably isn't the right word. Everyone seems to have a different concept of what it is, and so each has a different definition for it—usually based on their experiences and created to fulfill their own needs. Still, the desire to merge engineering disciplines, collaborate using model-based designs and add motion control software and real-world data to simulate and solve machine building problems earlier are all extremely useful goals, no matter what label is stuck on them.

Steve Bergholt, control system devlopment manager at Triangle Package Machinery in Chicago, says mechatronics is supposed to combine mechanics and electronics. A lovely sentiment. However, convincing engineers in an organization to actually practice it can be a very tall order.

"Because of how they were trained in the past, electrical and controls engineers don't do gears, pulleys and other mechanical devices. It's the mechanical engineers who worry about beams, stresses, bend radiuses and cam functions. And they, in turn, don't worry about voltages, amperages and controls. That's what the electrical and controls engineers worry about," says Bergholt. "Now, it's becoming more important for engineers to know about these other disciplines because machines and production lines are more complex and integrated as they take on more varied tasks and have to get them done faster."

For example, servo drives push controls more to the electronics side, explains Bergholt. "Previously, we'd have five different line shafts driven through linkages," he says. "Now, we can put in five servos, but we need to know more ahead of time about what they're going to do and which size motors they'll need to make the machine or its system work properly. That means the electrical and mechanical guys need to work together more closely. Mechatronics is needed to help us optimize performance benefits by knowing earlier what can be done on both the mechanical and electrical sides."

To foster the more collaborative, less sequential environment that mechatronics needs, Bergholt adds that Triangle took its mechanical engineers out of their own room, took its electrical engineers out of their own room and mixed them all together. "Now, they all sit next to each other, and they can lean over and talk and work together more before any prototypes are built," says Bergholt.  

Because their technical backgrounds and even the language they speak is often alien to each other, mechanical engineers, electrical engineers, controls engineers and software and IT engineers traditionally designed and built the same machine or project in sequence. Each engineering discipline separately added its contributions and requirements to a project at different times and in isolation from the others, and then "threw it over the wall" for the others to work on.

This drawn-out serial process is how machines and production lines traditionally were designed and built. However, this old procedure is increasingly less tolerable as builders strive to deliver machines to market faster, which also means they can't afford to build and rebuild costly prototypes.

Fortunately, a variety of software-based design and modeling tools also have grown up over the years to make it easier for engineers to share their designs with each other, check how designs will perform virtually, and wait to build physical prototypes to evaluate functions that can't be modeled and tested any other way. However, the ability to use new tools requires a mental shift, too.

For instance, Dr. Tommy Pool, electrical engineering manager at Kliklok Woodman, Decatur, Ga., believes everything his firm does as a packaging machine builder is mechatronics but adds he usually thinks of it as more than just electro-mechanics. "We don't build a totally mechanical machine anymore," explains Pool. "Technological advances are moving us away from the days when a machine might have had just one big motor and a line shaft. With servos, we're not as limited to straight gearing or camming. We can tailor the profiles of a motor to the size and shape of the package we're producing. And, we build machines that give our customers shorter changover times, which allow them to produce only the product they need for an order and then move on to another product. Changing over is no longer a big deal that would have required a shift or so of downtime. We try to use mechatronics to help our customers produce a better-quality product more quickly and more easily than before. I think this fits with lean business principles and has the potential to help our customers be more efficient."

Craig Therrien, product manager for Dassault Systèmes SolidWorks, adds, "The big shift right now simply is sending information back from the electrical and controls guys to the mechanical guys to help optimize their design. It's already been done in aerospace, automotive and nuclear applications, but it's new to machine building and test stands, and semiconductor manufacturers aren't doing it either. It's good for engineers to talk, but it really helps if they can get CAD designs that are fully integrated with motor-specific data and mass properties."

To many, it might seem unworkable to have colleagues from all of a machine builder's disciplines simultaneously yammering about what an end user wants in the machine and which specifications will and won't work. Doesn't the process have to start somewhere, so shouldn't it continue to start with mechanical engineering?

Sure, but one of mechatronics' primary goals is to help engineers practice more proactive give-and-take and solve more problems earlier in the collective design process, so they don't have make as many corrections, build as many prototypes and make as many field visits after installation. As a result, advocates of mechatronic-based design say a little added aggravation early on is worthwhile because of the benefits it delivers later.

For example, SquareOne Systems Designs in Jackson, Wyo., is a system integrator that builds automation and robotic systems and is striving to improve its collaboration abilities. The nine-person integrator builds its Trisphere scalable positioning device to place protein crystals in a neutron beam (Figure 1). Precise positioning is needed so the crystals' structures can be mapped and studied in a pharmaceutical research project at the U.S. Dept. of Energy's Oak Ridge National Laboratory. Lisa Mosier, SquareOne's mechanical engineer, says Trisphere uses small, light-load, small-increment piezo motors that work together to give it six degrees of freedom, including X, Y and Z axes, as well as the ability to rotate around any of those initial axes. It also uses larger ball and lead screws for heavier loads and longer travel distances.

"We do all the mechanical design work ourselves and then integrate controls to run our motors in specified paths," says Mosier. "We also develop our kinematic motion equations, and develop software to integrate them into our system. For us, mechatronics is designing our mechanical system so we can integrate its software at the same time. However, eight of our nine staffers are mechanical engineers, and so we tend to bring our designs far along on the mechanical side before bringing in our controls engineer to do the control software. Unfortunately, then it can be too late, and we have to do a lot of retrofitting and after-the-fact problem-solving. As a result, we're trying to move in the direction of involving controls earlier."

To assist its collaboration effort, SquareOne wants a standardized design platform and is exploring how to add National Instruments' LabView Soft Motion software module for SolidWorks to the SolidWorks software it already uses for its designs. "We've tried to do design reviews with all mechanical, electrical, controls and software parties, but it's far easier said than done," explains Mosier. "We lack the full electrical, controls and software knowledge that we need, and so it's easier to fall back on our mechanical knowledge. NI's Soft Motion module will allow us to use LabView to run limit-switch and full-motion simulations. We're also coming up with a simulation interface for developers making and testing devices, as well as standardizing our controls. As a result, SoftMotion will use motor commands from the interface to directly run the motors in the simulation. This will make the simulations  more true to life, give us better tests and prototypes, let us develop controls at the same time as our mechanical designs, and save time and expenses."

Not to be outdone by cooperation among flesh-and-blood engineers, several types of software also are being brought together to develop new and improved mechatronic functions and tools.

Rockwell Automation's Motion Analyzer software links to SolidWorks' software and lets mechanical engineers consider using lighter, stronger carbon-fiber components by showing how they'd perform. It also lets control engineers see how different motion profiles would affect the overall machine, and enables the electrical engineers to examine the effects of different voltage levels on the same design. Further, it lets them all find the best solution without having to rely as much on estimates and best guesses as they did in the past.

"We just worked with a European carton manufacturer that wanted to consider using robots," says John Pritchard, global products marketing manager for Rockwell's Kinetix motion business. "They identified 20 different robotic geometries that might be useful and wanted to evaluate them by scaling up and down and considering different building materials. In the past, the only way to do this would have been to build 20 prototypes. However, this summer we hired interns to build software-based mechanical models that could show these 20 geometries, which helped the carton builder reduce the prototypes it needed to just two, which reduced the time spent on this project from what would have been a couple of years to a couple of months."

Rockwell's Motion Analyzer software, NI's SoftMotion software module and other computer-aided design, manufacturing or engineering (CAD/CAM/CAE) programs that can accept and account for detailed motion data solve the throw-it-over-the-wall problem by linking mechanical and electronic/controls engineering departments via a rich flow of information that's automatic and accurate.

Similarly, Kollmorgen's MechaWare software partnered with The MathWorks' MatLab software to help users take model-based designs, implement algorithms and establish centralized or distributed controls for their machines.

Though machine builders and engineering schools in the U.S. must catch up to reach Europe's approximate 10-year lead in education and adoption of mechatronics, there are indications it's already happening. Purdue University recently began offering a four-year bachelor's degree in mechatronics. The university's Calumet campus in northwest Indiana reportedly found that there were many area packaging companies that needed engineers and technicians with packaging-related skills, and so they developed a mechatronics curriculum and degree program.

To give working engineers some of the same education, Kevin Craig, Ph.D., mechanical engineering professor at Marquette University in Milwaukee, facilitates workshops on mechatronic concepts and developing multi-disciplinary departments. For instance, 24 engineers and technical professionals from Procter & Gamble (P&G), Rockwell and Marquette gathered in August at P&G's Corporate Engineering Technology Lab (CETL) in West Chester, Ohio, for a three-day workshop that approaches mechatronics by giving the participants sample problems supplied by the end user and then dividing them into teams to devise solutions.

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"For example, the goal could be moving an object in a certain time profile through certain planes," says Craig. "The teams are given 20 device choices, and they have come up with the best choice or combination of choices. It gives participants a chance to build on what they know, and gain some insight into what the others do. For many organizations, it's the first time their suppliers and customers have come together in this way."

The workshop's process also helps everyone focus on what their users need by doing paper prototypes, creating a common modeling environment for everyone to see and using it to test and simulate together, explains Craig. "Mechatronics allows users to fix problems now that would be 10 times more expensive down the road," he says. "As a result, it moves beyond combining mechanical and electronic engineering to help engineers collaborate and tackle problems that are beyond their traditional disciplines."