Controllers Capabilities with Computational Tuning Algorithm in Nonlinear Electro-Hydraulic Actuator System

Abstract

Controller is an essential part in a system that playing a vital role especially dealing with the heavy machinery mechanism such as electrohydraulic actuator (EHA) system. It is proven in the past studies, the controller is necessary to be designed to reduce numerous defects such as nonlinearities and uncertainties which intrinsically exist in the EHA system. Therefore, different control approaches are presented and its performances are evaluated in this paper. Firstly, the conventional proportional-integral-derivative (PID) controller is designed, followed by the presentation of an improved PID controller called as fractional order PID (FO-PID) controller. Then the sliding mode controller (SMC) is designed, followed by the transformation on the sliding surface of the SMC controller with the PID control structure is carried out. The parameters of these four controllers are obtained by using the particle swarm optimization (PSO) tuning algorithm. The performances of these four different types of controllers applied in the EHA system are analysed. As a conclusion, it can be inferred that all of the controllers contain its own merit and demerit, which are considered as a trade-off between the controller’s performances and its design complexity. The improvement of 31. 41% has been obtained in the error analysis when the SMC-PID controller is applied to the EHA system.