Performance Evaluation of Optimized Controllers for Electro-Hydraulic Actuator Systems Under Mismatched Disturbances

Abstract

To address the precise tracking challenges caused by non-linearities and operation uncertainties in high-power-density electro-hydraulic actuators (EHA), this paper evaluates the performance of 3 distinct control schemes: a conventional Proportional-Integral-Derivative (PID) controller, a Modified Sliding Mode Control with Fixed Boundary Layer (MSMC-FBL), and Modified Sliding Mode Control with Variable Boundary Layer (MSMC-VBL) while utilizing a third-order mathematical representation of an EHA system. Parameters governing each of the control schemes are tuned using 3 different optimization algorithms: Particle Swarm Optimization (PSO). Gravitational Search Algorithm (GSA), and a combined hybrid, PSOGSA. The tracking capabilities and robustness of the control strategies are benchmarked under ideal nominal conditions (0 N) and extreme external mismatch disturbances (10 000 N). Simulation results indicate that the MSMC-VBL tuned with the PSOGSA algorithm delivers the best performance in comparison with other control-optimizer combinations when subjected to the external mismatch disturbance.