The work of the chassis load turning device is controlled by the hydraulic and electrical control system. Since the working mode of the chassis load turning device is bidirectional, the direction of the force of the turning bracket on the hydraulic cylinder is changed. Since the h value is a variable, the force on the hydraulic cylinder also changes. In addition, the size range of the cylindrical parts turned by the turning machine is large, and the weight of the parts is not fixed. These variables will cause the pressure fluctuation of the hydraulic system.