Mechanical system: mainly includes walking device, steering mechanism and working device. Hydraulic system: The function of this system is to convert the mechanical energy of the engine into hydraulic energy by using the fuel oil as the medium, and then transfer it to the cylinder, oil motor, etc. into mechanical energy. Control system: The control system is to control the engine, hydraulic pump, multi-way directional valve and executive components. Hydraulic control driving mechanism is a device which converts small power electric or mechanical energy into powerful hydraulic and mechanical energy in hydraulic control system. It consists of hydraulic power amplifier, hydraulic actuator and load. It is the core of static and dynamic analysis in hydraulic system.