Tutorial 3: High-Precision Motion Systems

Abstract: Modern machine tools, humanoid manipulators, spherical vehicle wheels and coordinate-measuring machines often require dexterous orientation control with several DOF, which are traditionally driven by open or closed chains of multiple single-axis actuating devices. Although single-axis motors can be controlled with high precision, small deviations in each joint could add up to a significant error at the endpoint of the kinematic chain. Along with illustrative examples, this tutorial focuses on several elements that play an essential role in a typical high-precision motion system. Specifically, the elements to be discussed are multi degrees-of-freedom (DOF) electromagnetic (EM) actuators, vision-based and optical sensors, model-based estimators for robust control, and selected application examples in robotics, automation and mechatronics. The first topic introduces methods of designing non-conventional EM actuators for high-precision multi-DOF motion systems.  As accuracy of a motion system often depends on its sensor, the second topic presents non-contact sensors with emphases on vision-based measurements for real-time multi-DOF motion control, very high resolution optical position sensing, and computational intelligence in sensing.  The third topic discusses methods to develop model-based estimators for control systems where direct measurements are difficult to make in real-time. Finally, several illustrative examples will be given to highlight the advantages, limitations and potential future developments of the above topics.

Biography: Professor Kok-Meng Lee received his B. S. degree from the State University of New York at Buffalo in 1980 and earned his S. M. and Ph. D. degrees from the Massachusetts Institute of Technology in 1982 and 1985 respectively, all in mechanical engineering. He is a Professor in the George W. Woodruff School of Mechanical Engineering at Georgia Institute of Technology. Dr. Lee’s research interests include system dynamics and control, machine vision, mechatronics, robotics, and manufacturing automation. Dr. Lee is a Fellow of ASME and IEEE. Other recognition of his contributions includes the National Science Foundation (NSF) Presidential Young Investigator Award, Sigma Xi Junior Faculty Research Award, International Hall of Fame New Technology Award, and the IEEE/ICRA Kayamori Best Paper Award. He holds seven patents in machine vision, three DOF variable reluctance spherical motor, and optical orientation encoder.