State feedback spool position control with integral compensation for servo proportional valve

Abstract

In recent years, servo proportional valves have been widely used in the industry owing to the advantages of high stability and low cost. However, the nonlinearity and parameter uncertainty present in the servo proportional valves make it difficult to control the spool position. This paper proposes a state feedback control with integral compensation for the spool displacement control of the servo proportional valve, which aims to solve the problem that state feedback is difficult to overcome system nonlinearity and parameter uncertainty. The key to this control method is the addition of an outer loop negative feedback and an integral element. At the same time, the control method can realize pole configuration, convenient control parameter adjustment, low hardware requirements, and easy engineering application. Experimental and simulation results show that the integral element can compensate for the system’s nonlinearities and uncertain parameters, and eliminate the steady-state error of displacement tracking. The state feedback with integral compensation can improve the frequency response of the servo proportional valve compared to traditional PID control.