关键词: 变转速液压源, 限幅模糊, PID补偿, 流量控制

Abstract:

In view of the existing defects in speed control of variable speed pump controlled hydraulic systems，such as slow response, speed fluctuation and low control accuracy, especially in the fast-changing load conditions, due to the strong coupling characteristics of flow and pressure, flow control became uncertain, variable and highly nonlinear, conventional PID control or fuzzy control were difficult to obtain satisfactory control results. A limiting fuzzy and PID compensation with threshold settings control strategy was presented herein. The control system firstly used limiting fuzzy control, which had fast response of open-loop control to approach target flow, then adopted PID compensation with threshold settings control to eliminate the system steady-state errors，and had a fast response, no overshoot, high precision advantages. The simulation and experimental results show: this method can realize the precise control of flow of variable hydraulic power source on typical conditions. Significantly reducing the steady-state errors of slope response, system control performance is much better than that of simple traditional control methods, and is suitable for the on line control of volume speed modulation of variable speed system.

Key words: variable speed hydraulic source, limiting fuzzy, PID compensation, flow control