Variable frequency hydraulic speed control system based on CANopen

This paper combined hydraulic transmission, frequency speed control and CAN bus communication together to establish variable frequency hydraulic speed control system. Inverter, PLC, sensors communicated with each other with CANopen protocol in the system. The system could vary speed in a wide range, control the motor speed precisely and improve the response time and stability of hydraulic system. The variable frequency hydraulic speed control test platform was built, two cylinders pulling reverse was adopted as a way of loading to test the system's speed control performance, we found that the motor response time equaled to the inverter acceleration or deceleration time. The actuator response time mainly depended on the motor response time, the hydraulic pump output flow and cylinder size. Low-frequency performance of the system was analyzed, the minimum static frequency under different loads of the system was obtained through experiments.