Abstract: Aiming at the currently widely used ΔKprule library of traditional fuzzy PID control algorithms, there was a problem of insufficient accuracy when the Kpparameters were corrected by the ΔKprule library online. A fuzzy PID algorithm after optimization of ΔKp rule library was proposed and its control performance was studied. According to the expert experience of PID tuning, the ΔKp rule library was analyzed and the unreasonable rules were dentified, then the ΔKp rule library was adjusted and improved to complete the optimization of the ΔKp rule library. The fuzzy PID controller was designed based on the optimized ΔKp rule library. Finally, with the help of multi-domain collaborative simulation technology, the valve-controlled cylinder system was taken as the controlled object to simulate the performance of fuzzy PID control with developed rules. The results indicate that the new ΔKp rule library is more flexible and accurate in online correction of Kp parameters than the traditional ΔKp rule library. It overcomes the problem of existing ΔKp rule library, the servo tracking precision and anti-interference capability of the improved fuzzy PID controller are improved significantly. Comparing with PID and traditional fuzzy PID, the control performance of the improved fuzzy PID controller is respectively improved by 18.62% and 32.61%.

Key words:  electro-hydraulic servo system; fuzzy PID control; rule improvement; co-simulation; position control