Quasi-synchronous control of uncertain multiple electrohydraulic systems with prescribed performance constraint and input saturation

This article focuses on the high accuracy quasi-synchronous control issue of multiple electrohydraulic systems (MEHS). In order to overcome the negative effects of parameter uncertainty and external load interference of MEHS, a kind of finite-time disturbance observer (FTDO) via terminal sliding mode method is constructed based on the MEHS model to achieve fast and accuracy estimation and compensation ability. To avoid the differential explosion in backstepping iteration, the dynamic surface control is used in this paper to guarantee the follower electrohydraulic nodes synchronize to the leader motion with a better performance. Furthermore, a time-varying barrier Lyapunov function (tvBLF) is adopted during the controller design process to constraint the output tracking error of MEHS in a prescribed performance with time-varying exponential function. As the initial state condition is relax by tvBLF, the input saturation law is also adopted during the controller design process in this paper to restrain the surges of input signals, which can avoid the circuit and mechanical structure damage caused by the volatile input signal. An MEHS experimental bench is constructed to verify the effectiveness of the theoretical conclusions proposed in this paper and the advantages of the proposed conclusions in this paper are illustrated by a series of contradistinctive experimental results.