Simulation of Coupling Characteristic of Hydraulically Driven Stewart Platform Based on Dynamics Model

Close chain of spatial mechanical structure of the hydraulically driven Stewart platform makes there exist coupling between the six degrees of freedom. In this paper, it builds the multi-body dynamics model of system with Kane method and then builds the dynamics model of the hydraulic servo system. Combining the two parts, it achieved the whole dynamics model of Stewart platform. By studying the coupling characteristic between six degrees of freedom with the model, it finds out the corresponding relationship of coupling between degrees of freedom and it also finds that dynamics coupling property of system increase with the frequency and reach the maxim value at the natural frequency. When the frequency is greater than the natural frequency the coupling property declines rapidly. At last it verifies the validity of the conclusion through the experiment, so it can use the conclusion as a foundation to study decoupling control strategy which is based on the dynamics model.