Dynamic Modeling and Robust Inverse Dynamics Control Enhanced by Optimal Equivalent Input Disturbance for a Shipborne Wave Compensation Hexapod Platform

The control of shipborne wave compensation Stewart-Gough platform (SGP) is affected by a variety of interferences. This study proposes a composite control scheme based on inverse dynamics control (IDC) to suppress multiple disturbances experienced by the shipborne SGP. A comprehensive system dynamic model is established. Primary potential disturbances are classified, and the corresponding suppression strategies are proposed. A robust term is added to the normal IDC to overcome the model parameter uncertainty, meeting the desired performance with internal parameter uncertainty. An equivalent input disturbance (EID) approach is introduced to resist the unknown external disturbances based on the robust feedback control. A Kalman filter is integrated to construct the Optimal EID to suppress the destructive effect of sensor noise on disturbance estimation, improving the accuracy of external disturbance estimation. The stability of the closed-loop controller is analyzed. Experimental results demonstrate that the proposed scheme exhibits superior resilience to internal and external disturbances compared with several conventional approaches.