Politecnico di Torino Graduate Student Demonstrates Value of Physical Modeling and Dynamic Simulation to Industry Partner Comau
“With Simulink and Simscape, you can quickly build simple models for design space exploration, select the one that looks most promising, and then develop that one further to produce results that accurately predict system behavior. Getting the design right the first time reduces costs substantially.”
Challenge
Demonstrate the potential cost and development time savings of incorporating modeling and simulation into industrial automation systems design
Solution
Use Simulink and Simscape Multibody to model an industrial lifter, analyze its dynamic properties via simulation, and size its DC motor
Results
- Critical design issue identified through simulation
- Simpler but equally effective model created in hours
- 20% in cost savings projected
The Comau industrial lifter.
To provide students with practical learning experiences, Politecnico di Torino faculty members work with engineering firms, manufacturers, and other industry partners to identify projects like those the students will encounter after graduation.
On one such project, a graduate student in the department of computer and control engineering not only gained invaluable work experience; he also solved a genuine technical problem for Comau – Special Projects, a sector of the major industrial automation group: how to validate the design of an industrial lifter capable of raising and lowering payloads of up to 500 kg. The student, Andrea Giacotto, used Simulink® and Simscape Multibody™ to model the lifter, run simulations to observe its dynamic behavior, and size the DC motor that turns the lead screw to actuate the lifter’s double scissor mechanism.
“Simulink and Simscape Multibody enabled Andrea to help Comau – Special Projects address a real technical problem,” says Dr. Massimo Violante, associate professor at Politecnico di Torino. “Specifically, he demonstrated how Comau could streamline special product development with dynamic simulations of physical models created in Simscape Multibody.”
Challenge
Comau engineers in charge of designing the lifter knew that if they used static analysis and a spreadsheet to size the electric motor, they would have needed to spend several months building a realistic prototype and testing it, with the potential risk or over- or under-specifying the system.
To demonstrate an effective way to speed up the designing and highlight the importance of building a prototype right the first time, Giacotto needed to model and simulate the lifter. In addition to correctly sizing the motor, he wanted to see whether a simple physical model would perform as well as a detailed model while saving costs and time.
Solution
Giacotto used Simulink and Simscape Multibody to model and simulate the lifter. Because MATLAB® and Simulink are fully integrated into Politecnico di Torino engineering curricula, he was already proficient in these tools. To learn the basics of Simscape™ and Simscape Multibody, he worked through examples on mathworks.com that had geometries similar to the lifter.
Next, Giacotto used Simscape Multibody to import a SolidWorks® CAD assembly of the lifter and generate a Simscape model that included the mechanical linkages, gearbox, and lead screw. He then added elements for modeling mechanical contact forces.
Giacotto ran numerous simulations with this model to determine whether the motor torque met the lifter’s payload specifications. He performed a sweep analysis by writing a MATLAB script that automatically modified model parameters across a range of values, launched simulations, and plotted simulation results.
After completing the analysis with the CAD assembly–based model, he repeated it using a simplified model, created in Simulink Multibody, consisting of just two plates, two axes, and a load.
Finally, Giacotto conducted a cost-benefit analysis that took into account factors such as licensing and training as well as reductions in errors, redesign effort, and overall development time.
Giacotto identified steps that Comau could take to further improve its workflow, including incorporating motor dynamics and a controller design into the model and automatically generating embedded C code for the control system.
Giacotto shared his findings with the Comau – Special Projects engineering team responsible for the lifter. Recognizing the value of the modeling and simulation approach Giacotto had used, the team invited him to present the results of his analysis to senior management. Comau Robotics and Automation Products has already implemented this approach and Comau – Special Projects plans to do the same on future projects.
Results
- Critical design issue identified through simulation. “The simulations performed with the first Simscape Multibody model showed that the torque estimation arrived at through a simple static analysis was too low,” says Violante. “Running dynamic simulations in Simulink before building a prototype revealed that more torque was needed to start moving the lifter.”
- Simpler but equally effective model created in hours. “It took the student just two hours to create the basic model of the lifter in Simscape Multibody,” Violante says. “Even though it was a much simpler model—with just a few elements and no contact forces—it did just as well at identifying the design error related to insufficient motor torque.”
- 20% in cost savings projected. “Giacotto’s detailed cost-benefit analysis showed that the use of Simulink and Simscape for dynamic simulations would have shortened time-to-market for Comau by months and reduced development costs by 20–40%,” says Violante. “Even greater benefits were projected as the company’s engineers gained experience with the tools and expanded their use to other projects.”
