SPOOL POSITION CONTROL OF PIEZOSTACK VALVE SYSTEM OPERATED AT VARIOUS TEMPERATURES

摘要

This paper proposes a spool valve system actuated by a piezostack actuator and investigates control performance from room temperature to high temperature (150 °C) using fuzzy PID controller. In order to achieve this goal, a piezostack driven spool valve system is designed and an experimental apparatus is setup to evaluate control performance with high temperature conditions. The experimental apparatus consists of a heat chamber, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, thermal insulator, and electronic devices such as a computer, data acquisition (DAQ) board, sensors, and a high voltage amplifier. The piezostack actuator is insulated from heat because the piezostack actuator cannot generate the blocking force if the actuator is heated to higher than Curie temperature. After designing a fuzzy algorithm integrated with PID controller, experimental implementation is realized. Experimental results are compared between room temperature condition and high temperature conditions. The experiment results are presented in both time and frequency domains.