| Direct Drive Volume Control (DDVC) electro-hydraulic servo system also named valveless electro-hydraulic servo system, has the advantages of flexibility of motor control and high power of hydraulic servo system. It is stronger anti-pollution, higher efficiency, smaller integration, more convenient operation and economical than traditional electro-hydraulic servo system. It has been used in many areas, and made great economic benefits. But the weak dynamic performance restrict it's further application. Therefore, the study of the DDVC electro-hydraulic servo system has the vital significance to enhance system performance, improve value in practical application and extend application prospect.This technology of DDVC is gradually perfect in foreign country especially in USA and Japan, and its application is increasingly abroad. The main work of this paper is studying the dynamic and static performance of the DDVC electro-hydraulic servo system and doing experiment.This paper introduces the working principle and control methods of permanent AC servo motor, analyzes the pump-control cylinder subsystem, establishes the mathematical model of AC servo motor and pump-control cylinder subsystem. In addition, establishes the mathematical model of the whole system. It also analyzes the parameters which influence the system's dynamic performance. Then, the computer simulation is performed to the system. Besides that, this paper programs the control software, designs PID controller and adaptive controller.Experiment validates that the mathematical model is good in describing the system. Contrastive analysis of the effect of the two controllers lays foundation to performance optimization of system. In addition, this paper adopts some improvement measures. In order to eliminate interference, the servo motor is isolated, the signal circuit is filtered in experiment. |
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