Introduction to quantitative feedback theory for robust force control of load simulator

This paper presents a new kind of hydraulic load simulator (HLS) for conducting performance and stability test for control forces of hydraulic hybrid systems. For the purpose of improving force control performance of hydraulic hybrid systems, a robust force controller using quantitative feedback theory (QFT) technique applied to the HLS is also proposed in this paper. The controller is designed to satisfy the robust performance requirement, tracking performance specification, and disturbance attenuation despite uncertainties of HLS. Experiments are carried out to evaluate the effectiveness of the proposed control method applied for hydraulic systems with varied external disturbance as in real working conditions.