气动重力补偿系统的压力控制

With the development of aerospace science and technology, the gravity compensation device takes a very critical role in simulation of zero gravity environment. A pneumatic gravity compensation system based on the aerostatic frictionless cylinder is constituted. Pneumatic gravity compensation system is a typical nonlinear system. It is particularly difficult to establish accurate mathematical model and achieve high precision pressure control. The second order mathematical model for pneumatic gravity compensation system on the basis of proportional flow valve and frictionless cylinder is established. A fairly reference accurate model is provided for control algorithm during the in the course of modeling. Pressure differential sensor which can extract pressure differential effectively and restrain noise is designed by isothermal chamber and laminar line. Based on active disturbance rejection control technique high-precision pressure control algorithm is proposed to suppress the disturbance and high-precision dynamic gravity compensation of is realized. Experimental results show that the controller has good robustness against the influences of payload, air supply pressure, the steady-error is less than 67 Pa and the dynamic-error(0.1 Hz) is less than 1000Pa.