The smoothness of acceleration and deceleration process is a serious problem in valve control system with high inertia load, especially in the hydraulic systems in construction machines.
In this paper, a meter-in and meter-out independent regulating method, in which the two sides of actuator are controlled by a meter-in valve and a meter-out valve respectively, is put forward, in one hand, the meter-out valve could control the actuator’s outlet pressure to avoid the ultra-high outlet pressure when actuator decelerates or brakes suddenly. On the other hand, the dynamic damping ratio of valve control system could be raised through calculated flow feedback control algorithm.
Secondly, a grading control algorithm in dynamic process of high inertia load is adopted. When the actuator’s velocity is far from its command value, the actuator’s inlet and outlet pressure are controlled. After the velocity error decrease to a threshold, a state feedback control algorithm based on parameters on line estimating is employed to realize both its velocity accuracy and the smoothness of dynamic process.
Experiments show that the actuator’s velocity could increase or decrease to its command value accurately, smoothly and rapidly after the above method and algorithm are applied.