Study of ADRC on fluid power transmission system control characteristics of 60MN hydraulic press

Heavy forgings quality and production capacity represent an important symbol of the level of the country´s industrial development. Large water press is the equipment for heavy forgings forming, and it´s essential to improve the control performance of power transmission system. In this paper, the mathematical models of the key elements for fluid power transmission system, including water pump, accumulator, inlet valve, outlet valve, main distributor, prefill valve, pipeline, actuator, load, working medium, electro-hydraulic servo system, are established, and the complete mathematical model of fluid power transmission system is derived. Based on the mathematical model of electro-hydraulic position servo control system of hydraulic press, the load characteristics of the electro-hydraulic position servo control system are analyzed, the strategy of active disturbance rejection control (ADRC) is derived, the principle of selecting the control parameters is obtained. Furthermore, the effect of ADRC control and PI control of hydraulic press is analyzed under no load, step, sinusoidal and ramp disturbance force respectively. The results show that: compared to the PI control, the ADRC can make distributor more rapid and sensitive, and improve the control performance and anti-disturbance capability of electro-hydraulic servo system of hydraulic press, and improve the overall response speed and compensate the position control accuracy under the low-frequency disturbances. Above research work can provide theoretical and experimental basis for studying on control method of fluid power transmission system of 60MN hydraulic press.