Research Of The Dual-valve Electro-Hydraulic Control System Of The Elevating Machine Of Gun

Improving the performance of the elevating machine is very important to improve the overall performance of the gun especially the fire accuracy. Traditional elevating machine uses a single large flow rate servo valve to control, which has low frequency and resolution, along with the continuous improvement of the technical requirements, it can’t simultaneously satisfy the high and low speed that the system need. In order to improve the minimum speed and the steady accuracy of the system, a large flow servo valve and a smaller one’s parallel control scheme is adopted. Compared with using a large flow servo valve with high accuracy, this scheme not only improves the speed range of the system, but also reduces the cost.Firstly, the mathematical model of the system is established through rational simplification according to the characteristics of the hydraulic elevating system. Then we analyze the changes of the main parameters during the operation of the system; discuss the dominating factors which affect the steady error of the system and design a PID compensator for it. In order to make the simulation results more close to the actual system’s characteristics, the AMEsim model of the system is established.Design an observer to compensate the bias/zero drifts of the big servo valve during the parallel control and verify the good performance of the compensator through simulation; the control strategy is brought forward and the process of the direct switching,the gain gradual change switching and the fuzzy switching are analyzed; further more we optimize the main parameters of these two process.Design a sliding mode controller for the system, which has the time-varying parameters, strongly nonlinear properties, uncertain and various factors, based on exponential reaching law; design a global sliding mode controller to solve the SMC controller’s poor robustness in the reaching process; aiming at the chattering problem and the problem that the uncertainties is hard to estimate ahead, a dynamic sliding mode controller is designed, combine SMC with switching control to simulate the system and get ideal results.Design the experiment based on x PC Target Real-time simulation environment and hydraulic bench; verify the sliding mode controller by its tracking performance to different signals; confirm gain mutation will cause the impact phenomenon and indirectly proves the necessity of the gain gradual change switching as a result; prove the compensation effect of the disturbance observer to the zero bias/zero drift of the system.