2002 年 2002 巻 5-1 号 p. 143-148
In recent years the water has been paid attention as a working fluid again, for the demand of the technology considering the global environmental problems. In this paper we compose the water hydraulic servo system by combining a servo valve and a hydraulic motor and we study the control performance of rotational angle. The problem in the system is the existence of unmodeled dynamics, e.g. large starting torque and friction force of water hydraulic servomotor, which cause the significant performance degradation. We composed the gain scheduled PID -controller that improves the large steady state error and overshoot. We are succeeding fairly in attenuating the steady state error of water hydraulic servomotor.