Chun-Liang Lin*, Chun-Hsiung Chen** and Van-Tsai Liu***
*Department of Electrical Engineering, National Chung Hsing University, Taichung, Taiwan 402, R.O.C.
**Institute of Electrical and Information Engineering, Feng Chia University, Taichung, Taiwan 40724, R.O.C.
***Department of Electrical Engineering, National Huwei Institute of Technology, Yunlin, Taiwan 63208, R.O.C.
Operating time delay in the solenoid valves is very common for practical electro-hydraulic servo systems. It may sometimes cause performance degradation or even instability if it isn't treated carefully during control system designs. We propose in this paper a non-model-based design approach for hydraulic actuating systems based on a new time-delay compensation scheme. In the proposed system, two types of controllers are combined: a fuzzy-PID controller used to ensure primary tracking performance and an adaptable wavelet compensator used to compensate for the time delay re-sulting from the control valve. Performance of the proposed design is widely verified on a newly developed simulation platform to show its effectiveness.
Keywords: Hydraulic system; position control; time-delay; fuzzy control; wavelet neural network