Zero Point Compensation Control of the Proportional Valve with Negative Overlap

In order to improve the performance of the negative overlapped valve controlled asymmetrical cylinder system, a theoretical zero point model of the valve with symmetric and unequal negative overlap was established. The simulation results showed that the zero point of the system will shift as the load changes, and the error of the theoretical zero point is relatively larger in some certain pressure states. In order to find the zero point quickly and steadily and improve the positioning accuracy of the system, a zero point compensation controller based on theoretical zero point plus error integral control was designed. Compared the pure P controller with the compound control of P controller and zero point compensation controller, the control accuracy of the system has been greatly improved under transient load and sinusoidal load interference.