The Force Control of a Novel Variable Rotational Speed Hydraulic Pump-Controlled System Using Adaptive Fuzzy Controller with Self-Tuning Fuzzy Sliding-Mode Compensation

The conventional hydraulic valve-controlled systems have high response but low energyefficiency. Hydraulic pump-controlled servo systems have high energy efficiency. However, the conventional pump-controlled systems, which are altered by displacement via variable displacement pumps, have lower response. This paper aims to investigate the force control performance of the high response electro-hydraulic pump-controlled systems driven by an AC servo motor with variable rotational speed. Instead of internal gear pumps, a constant displacement axial piston pump is used in this research. Thus, the new hydraulic pump-controlled system with an AC motor servo and a constant displacement axial piston pump is investigated for force control of hydraulic servo machines. For that, a novel adaptive fuzzy controller with self-tuning fuzzy sliding-mode compensation (AFCSTFSMC) is proposed for force control in the variable rotational speed pump-controlled system (VRSPCS). Thus, the developed high response variable rotational speed pump-controlled systems controlled by AFC-STFSMC are implemented and verified experimentally for force control in different force targets. The experimental results of the force control in the VRSPCS show that the proposed system and control method can achieve excellent control performance and robustness with regard to parameter variations and external disturbance.