Abstract: The motion platform is widely used to simulate the movement of ship and vehicle, which is of great value for testing of ship and vehicle equipment, motion simulator for training to steer. A novel digital hydraulic 2-DOF motion platform for simulating marine environment is developed. The system configuration and operating principle approximating to open loop control are introduced, which include incremental stepping motor, four-edge slide valve, asymmetric hydraulic cylinder and structure of motion platform, as well as synchronous feedback mechanism. The detailed kinematic and dynamic equations of each component are set up, especially the jump characteristics of valve-controlled asymmetric cylinder is described through the state equation. The nonlinear control model diagram of the system is established in Matlab/Simulink. Comparative analysis of the simulation and experiment results proves the feasibility of the digital hydraulic motion platform.

Key words: 2-DOF motion platform, Asymmetric hydraulic cylinder, Digital hydraulic valve, Nonlinear control model, Stepping motor