| Electro-hydraulic position and pressure hybrid controlling process widely used inmetal processing and molding equipment, whether the controlling performance is goodor not plays an important part on product quality and equipment safety. So the researchon electro-hydraulic position and pressure hybrid controlling algorithm and strategy isof great significance.In this paper, the loaded cylinders system with two servo proportional valvecontrolled asymmetric cylinder was regarded as researching object and themathematical models of position&pressure control system were established accordingto the working principle of electro-hydraulic servo system. Analyzed the shortcomingsof the traditional PID control and then introduced of a closed-loop PID-type iterativelearning control algorithm. Combining with the electro-hydraulic servo controlcharacteristics, the iterative learning controller was designed. For the impact of thevoltage surge on system stability caused by the switching between two closed-loopcontroller in the process of electro-hydraulic position and pressure hybrid control, abumpless control strategy was utilized based on a feedforward tracking compensationmethod and a bumpless controller was designed to realize the actuator switching fastlyand smoothly between position and pressure closed-loop control.In order to the feasibility of the algorithm, the Closed-loop PID-type iterativelearning control programs were written with Matlab language, the bumpless controllerwas designed and the mathematical models of position and pressure hybrid controlsystem were established to do simulink simulation analysis. Conclusion drawing fromhybrid controlling simulation is that this method can achieve the complete tracking ofthe input signal in electro-hydraulic servo system, eliminate the impulse voltageeffectively and realize the actuator switching fastly&smoothly between position andpressure closed-loop control. It is of great significance to improve the controllingperformance and product quality. |
PDF Full Text Request