Hardware-in-the-Loop Implementation of Optimized Fractional-Order PID Control for Electro-Hydraulic Position Tracking

Industrial hydraulics has made extensive use of the electro-hydraulic actuator (EHA) system. However, prevalent limitations such as uncertainties, non-linearities, and disturbances exist in most mechanical systems and restrict the optimal operation of the EHA system. To address these issues effectively, this study proposes a particle swarm optimization (PSO)-tuned fractional-order proportional-integral-derivative (FOPID) controller. Firstly, the EHA system is modeled using system identification. Then, by modifying the fractional order of the proportional-integral-derivative (PID) algorithm, a reliable controller is established and PSO has been applied to obtain the optimal FOPID controller parameters. Finally, the comparison works are conducted through simulation and experiment between the proposed FOPID and the proportional-derivative (PD) and PID controllers. Based on the error analysis evaluated in the designed sinusoidal (0.35 Hz), point-to-point, and chaotic responses, a significant improvement of 97.7%, 98.4%, and 97.8%, respectively, has been achieved by the FOPID controller as compared with the PD controller and 64.7%, 51.8%, and 47.5%, respectively, has been accomplished in comparison to the experiment’s PID controller. Furthermore, under extreme variation conditions, the proposed FOPID controller produced significant system performance improvement by 84.3% relative to the PD controller and 36.8% relative to the PID controller.