FeedBack linearization H∞ robust control of digital hydraulic cylinder position tracking system

This paper deals with the problem of designing a controller for a digital hydraulic cylinder position tracking system. Traditional control of this system is open-loop because of its special inner feedback structure which makes digital hydraulic cylinder auto-track the input signal until reaching assigned position. But the performance of this control methods has obvious delay comparing with input signal. To obtain a better position tracking controller, we will first establish the nonlinear model of digital hydraulic cylinder position tracking system. With feedback linearization theory, we translate the nonlinear model into a linear one. On the base of linear model, a position tracking controller is designed by using H∞ control and LMI(Linear Matrix Inequalities) theory. The similation and experiment results of the controller designed by this paper are compared with traditional controller. The results show that the controller proposed by this paper has much better performance then traditional one.