Internal Model Control using EWMA for speed control of wedge-type piezoelectric motors

In this article, speed control for a platform driven by a wedge-type piezoelectric motor is investigated. Such a motion control system is subject to disturbance like friction, preload and operating temperature change, so that a predictive linear relation between the applied input voltage and the output platform velocity is difficult to keep. Especially, operating temperature change is an essential problem of using piezoelectric motor, but very few researches introduce the phenomenon in depth and solve the problem. In practical experiment, deterministic drift due to operating temperature change is found and defined as a ramp-function disturbance. Similar to Chemical Mechanical Polishing (CMP) in semiconductor manufacturing process with a linear relation between the input recipe and the output target in a Run-to-Run (RtR) control structure, Exponentially Weighted Moving Average (EWMA) method has been widely used and verified its capability of overcoming systematic change and drift disturbance. Therefore, EWMA method on the basis of RtR control structure is considered to use for speed control purpose. Besides that, it is attempted to map the EWMA method into an Internal Model Control (IMC) to achieve an RtR-IMC adaptive control scheme. Following that, adding a PI compensator in the feedforward path is theoretically proved to be able to deal with the ramp-type disturbance due to operating temperature change. A number of feedback control methods including Single EWMA, Double EWMA, and RtRIMC_EWMA with a PI compensator design are investigated and examined. From experimental results, Double EWMA with two-stage parameter estimation, as expected, is able to deal with the drift noise and outperforms Single EWMA. The proposed RtR-IMC_EWMA with a PI compensator is superior to other methods. Such a new adaptive control scheme is easy to establish and provides flexibility of adding compensator in the feedforward path to enhance the robustness to external disturbance.

[1]  Uwe Dr Schaaf.  Pushy motors (piezoelectric motors) , 1995 .

[2]  Armann Ingolfsson,et al.  Run by run process control: combining SPC and feedback control , 1995 .

[3]  J. Stuart Hunter,et al.  The exponentially weighted moving average , 1986 .

[4]  S. W. Butler,et al.  Supervisory run-to-run control of polysilicon gate etch using in situ ellipsometry , 1994 .

[5]  Yuan Kang,et al.  Internal Model Control Using EWMA for a Wedge-Type Piezoelectric Motor , 2007 .

[6]  Yung Ting,et al.  Dynamic analysis and optimal design of a piezoelectric motor , 2003, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[7]  Toshiiku Sashida,et al.  An Introduction to Ultrasonic Motors , 1994 .

[8]  Shigeru Okuma,et al.  PWM driving characteristics of robot hand with fingers using vibration-type ultrasonic motors , 1997, Proceedings of the IECON'97 23rd International Conference on Industrial Electronics, Control, and Instrumentation (Cat. No.97CH36066).

[9]  Ceramic/metal composite piezoelectric motors , 1998, 1998 IEEE Ultrasonics Symposium. Proceedings (Cat. No. 98CH36102).

[10]  Ruey-Shan Guo,et al.  Run-to-run control schemes for CMP process subject to deterministic drifts , 2000, 2000 Semiconductor Manufacturing Technology Workshop (Cat. No.00EX406).

[11]  Ruey-Shan Guo,et al.  Run-to-run control of CMP process considering aging effects of pad and disc , 1999, 1999 IEEE International Symposium on Semiconductor Manufacturing Conference Proceedings (Cat No.99CH36314).

[12]  S. Adivikolanu,et al.  Internal model control approach to run-to-run control for semiconductor manufacturing , 1997, Proceedings of the 1997 American Control Conference (Cat. No.97CH36041).

[13]  Valentinas Snitka,et al.  Positioning To Nanometer Resolution With Ultrasonic Actuators , 1995, Proceedings of the International Solid-State Sensors and Actuators Conference - TRANSDUCERS '95.

[14]  Evanghelos Zafiriou,et al.  Robust process control , 1987 .

[15]  Bengt Klefsjö,et al.  Statistical process adjustment for quality control , 2003 .

[16]  Rong-Jong Wai,et al.  Design of Total Sliding-Mode-Based Genetic Algorithm Control for Hybrid Resonant-Driven Linear Piezoelectric Ceramic Motor , 2007, IEEE Transactions on Power Electronics.

[17]  Rong-Jong Wai,et al.  Intelligent motion control for linear piezoelectric ceramic motor drive , 2004, IEEE Transactions on Systems, Man, and Cybernetics, Part B (Cybernetics).

[18]  Tomonobu Senjyu,et al.  Speed control of ultrasonic motors using neural network , 1998 .

[19]  Katsuhiko Ogata,et al.  Discrete-time control systems , 1987 .

[20]  T. Ohmi,et al.  Highly Reliable Piezoelectric Actuator for Precision Stage System , 2005 .

[21]  Armann Ingolfsson,et al.  Stability and Sensitivity of an EWMA Controller , 1993 .

[22]  S. Adivikolanu,et al.  Extensions and performance/robustness tradeoffs of the EWMA run-to-run controller by using the internal model control structure , 2000 .