Abstract:Aiming at the problem that the control system of redundant driven parallel mechanism is not combined with dynamic modeling and the dynamic and static characteristics of servo valve are not considered in the design of the control system, a fifthorder transfer function model of electrohydraulic servo system was presented based on Lagrange equation of the second kind and hydrodynamics to model the mechanical and hydraulic systems of the moving platform and hydraulic system. The dominant energy optimal model was reduced to a three order model. Reducing order to more easily processed order was convenient for subsequent dynamic control. A H∞ robust control strategy based on TVC feedback optimization was proposed for the control object. It was further compared with TVC control and TVC-FAPID in step signal, linear sweep and actual broadspectrum. The comparison showed that the proposed TVC feedback effectively expanded the systems bandwidth and improved the damping ratio and natural frequency of the hydraulic system. So that H∞ robust controller can compensate the phase lag of high frequency signal. Therefore, the TVC-ROB improved the tracking performance of the highfrequency system obviously, and the displacement error percentage was only 1.26%. The H∞ control was introduced to improve the antidisturbance and antinoise performance of the system. In the high frequency section, the control energy loudness of TVC-ROB and TVC-FAPID strategies was much lower than that of TVC control, which tended to be stable. In the low frequency band, the parameters tuning of TVC control strategy was simple and easy to implement. So the TVC control strategy was often applied in engineering field. The research results had a strong guiding significance and reference value for the design of controller.