Lei Zhou uses her interdisciplinary precision mechatronics research as a powerful tool for solving problems in various application areas, including semiconductor manufacturing equipment and robotics. With a systems focus, she develops novel and high-performance mechatronic solutions by exploiting the synergy between precision machine design, electric machines, and control algorithms.
Most of today’s mechatronic systems are designed sequentially—designing mechanical systems and actuators first, followed by control. However, this approach may lead to conservative results, according to Zhou. For example, when control engineers begin working on the system, they might be unable to implement the best control solutions due to the mechanical and electrical engineers’ earlier decisions on the machine and actuator design.
That’s why Zhou emphasizes a synergistic “co-design” approach in her research, where important aspects of machine design, electromagnetic design, and control are considered simultaneously from a system perspective. Zhou says this approach allows researchers to develop more innovative solutions and achieve better performance in mechatronic systems.
“One unique thing about my lab is that I train my graduate students to work on all the key aspects of a mechatronic system. So, they do modeling, machine design, electromagnetic design, control algorithms, and implementation, and this helps to break down some disciplinary boundaries,” says Zhou, an assistant professor who joined the faculty in August 2023 with a joint appointment in the Department of Mechanical Engineering and the Department of Electrical and Computer Engineering. “The students learn how to work from a system perspective, which enables them to solve bigger, more complex challenges.”
She is also an associate director of the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC).
Zhou earned her PhD in mechanical engineering from Massachusetts Institute of Technology in 2019. She received her bachelor’s degree in control and instrumentation engineering from Tsinghua University in China and her master’s degree in mechanical engineering from MIT. Prior to joining UW-Madison, Zhou was an assistant professor in the Walker Department of Mechanical Engineering at the University of Texas at Austin.
One of Zhou’s current research projects focuses on designing precision positioning systems for high-throughput semiconductor chip manufacturing. In these manufacturing systems, the motion stages carrying the silicon wafers and photomasks move extremely fast, and their acceleration capability is a key determining factor in manufacturing productivity. Zhou is investigating mechatronics solutions that could break a current tradeoff in control bandwidth and acceleration capabilities in precision positioning stages. This could enable new patterning instruments with increased manufacturing throughput.
She’s also working on developing novel actuation, sensing and control solutions for high-performance robots used in manufacturing factories. Specifically, she’s focused on designing robotic hands or grippers that can better interact with the environment and perform more complicated tasks. Currently, robotic hands are limited by a tradeoff between dexterity, safety and strength. Industrial robotic grippers are very strong but not safe around people. On the other extreme, soft robotic hands are very dexterous and compliant when interacting with objects, but they lack strength. To overcome this tradeoff, Zhou is studying a new motor design with high torque and high interaction capabilities and will also explore the new robot-level capabilities endowed by this fundamental advance in actuation.
“The mechanical engineering department at UW-Madison is very interdisciplinary, and I’m looking forward to many great opportunities for collaboration,” Zhou says. “And my joint appointment with ECE and affiliation with WEMPEC will give me even more freedom to do interdisciplinary research and to hire students from both backgrounds, who can also learn from each other. In addition, my research on electric machines and control is a great fit for WEMPEC, and I’m excited to be a part of this prestigious consortium and to have access to many opportunities for industrial collaboration.”
In fall 2023, Zhou is teaching a new undergraduate course in mechanical engineering called Introduction to Mechatronics, where students will have many hands-on learning opportunities using a new mechatronics platform developed by Erick Oberstar while he was an ME faculty associate. Zhou says the course will give ME students an introduction to electrical engineering, teaching them about electronics, control and computing.
“This training will equip the students to make the jump from being mechanical engineers to being mechatronic engineers, and this will also benefit their future career prospects because mechatronic engineers are in very high demand in many industries,” she says.
Top photo by Joel Hallberg