水圧サーボモータシステムのロバスト制御に関する性能評価（第１報 Ｈ∞制御手法による制御系設計）

Abstract

With the recent increased concerns over global environmental problems, the water hydraulic technique using pure tap water as a pressure medium has become a new drive source comparable to electric, oil hydraulic and pneumatic drive systems. This technique is also preferred due to its power, high safety against fire hazard in production plants, and easy availability. However, the main problems for precise control in a water hydraulic servo motor system are steady state errors and overshoot due to its large friction torque in the low velocity range of a motor. This accounts for the development of a strategy to compensate for such uncertainties and to ensure a closed—loop system maintain its specified performance. In this research, the rotational angle and velocity control of a water hydraulic servo motor were considered with the H∞ control, the disturbance—observer—type control, the sliding mode control (SMC) and the adaptive control methods. We examined the motor control performance for load fluctuations. In this paper as the first report, controllers with H∞ theory were designed and applied to the water hydraulic servo system. This theory can explicitly treat uncertainties in a plant based on the mathematical model and/or frequency response. Two types of controller were designed, an 1DOF(Degree Of Freedom) —H∞ controller and a 2DOF controller. In the latter, the feedback controller was designed with H∞ theory. The control results show the easy implementation of controllers and the superiority of the 2DOF controller for angle and velocity control in the 1DOF—H∞ case.