Professor Tsu-Chin Tsao and graduate student Herrick Chang receive best paper award
September 24, 2010
UCLA Mechanical and Aerospace Engineering Department Professor Tsu-Chin Tsao was involved in two paper awards.
Prof. Tsao and graduate student Herrick Chang received the Best Paper Award in the International Symposium of Flexible Automation held in Tokyo, Japan, July 2010, for the paper “Repetitive Control of a Levitated Shaft – FPGA Implementation based on Powell-Chau Filters."
Abstract: Motivated by needing to generate precise periodic scanning trajectories at sampling rate above 100 kHz for application in micro and nano technology, Professor Tsao’s group has realized advanced control algorithms at 100 KHz sampling rate using field programmable gate array (FPGA). Such high sampling rate control cannot be realized by general processors due to latency in data transmission. The paper presents a linear phase plant inverse filtering and used it in the repetitive control loop by modifying a special digital filter realization methods based on the Powell-Chau and Kurosu filters. The 100 KHz sampling rate achieved was not limited by the FPGA but by the particular analog converter used so it can readily be made much faster than 100 KHz and thus can be particularly useful for the control of high frequency micro or nano devices.
Graduate Student Shalom Ruben was Finalist of the Student Best Paper Award in the American Control Conference, Baltimore, June 2010, for the paper “Optimal Commutation Law by Real-Time Optimization for Multiple Motor Driven Systems,” written by Ruben and Tsao.
Abstract: Thermally caused distortion of motion stage caused by motor’s electric heating during movement or dynamic force balance has been a concern for achieving nano precision. Realizing this problem, the paper proposed a motor coil commutation law, which generates desired stage forces while minimizing the power generation with or without additional constraint on equal motor power for symmetric thermal gradient. By exploiting the redundancy of motor coils and motor force generation that exists in the over actuated motion platform, the paper formulated a constrained optimization problem and solved it in real-time under 35 microseconds, within the 9 KHz coil commutation rate, and demonstrated motor control experiment with this underlying commutation laws.