| The force output of the asymmetric cylinder controlled by symmetric valve is choosen to be the controlled object in the hydraulic servo system that we studied. The controlled system has much defect, such as asymmetry of the dynamic characteristic, low accuracy, bad stability. On the contrary, self-adaptive control can eliminate model error, restrain outside disturbance and parameters'change of the system. For these reasons, we can apply the theory of the model reference self-adaptive control syetem design based on the theorem of balance point stabilization in the force system of asymmetric cylinder controlled by symmetric valve. The main idea of model reference self-adaptive controller is to make the self-adaptive control error incline to zero as time passed. The task to design adaptive controller is to find the control input that can make the output of the controlled system to follow that of the reference model. The performance of the controlled system can be improved by the adaptive controller. We can get perfect output through software controlling so as to improve asymmetry of the dynamic characteristic, low accuracy, bad stability, slow response of the asymmetric cylinder controlled by symmetric valve force system.More precise mathematical model for the force system of asymmetric cylinder controlled by symmetric valve has been built in the project firstly, then we get the controlled object through simulating and analysing its performance, and then we choose a system which has been adjusted to satisfy our requirements to be the reference model of our adaptive control. Model reference adaptive controller has been designed according to the theorem of balance point stabilization. Lastly, the designed controller has been applied in the force system of asymmetric cylinder controlled by symmetric valve to simulate, thus we can get the perfect control parameters of the controller. Simulation results test that the adaptive controller can eliminate dynamic asymmetry of the output, reduce the effect of the modeling error, restrain the bigger pressure break and libration of the system so as to improve the follow precision and ensure the stability of the system. The controlled system has good follow and repetition performance for these reasons. When we considering the dynamic characteristic of the servo valve,... |
