Study Of Ring Torque Motor Dynamic Sliding Mode Control

The thesis is proposed based on the project (No.2009A554) sponsored by education department of Liaoning Province.The thesis aims to apply dynamic sliding mode control theory to control the system status based on mathematical model of direct drive turntable system for permanent magnet ring torque motor, and then realize the location track of angular displacement accurately.When permanent magnet ring torque motor is used to drive the numerical control (NC) turntable servo system, the mechanical transmission links in the system is eliminated, the main advantage is as follows:high dynamic / static servo stiffness,fast dynamic response,high tracking accuracy of position and velocity,tight structure and small mechanical noise. However, the adoption of direct drive doesn't mean that the control performance of system can be improved absolutely, in fact, after using the direct drive method, technical issues for traditional drive will alter to independent solution with "Electricity", and this makes the system more difficult to control, so more advanced and special modern control theory should be adopt to keep the system have strong anti-interference ability and high dynamic stiffness.As for the design of controller, the paper first derives the dynamic integral sliding mode controller, then carries on the estimation of parameter uncertainty for dynamic sliding mode controller according to adaptive control theory, the main purpose is to weaken the buffeting of dynamic sliding mode controller, although the adaptive dynamic integral sliding mode controller designed have good transient response and steady-state error, if the load disturbance changes, that means problem of unmatched disturbance suppress should be taken into consideration when designing the controller, this disturbance will make the system unstable. In order to solve this problem, the paper combines H∞ robust control with adaptive dynamic integral sliding mode controller to restrain the load torque disturbance, which can improve the robustness of system.Finally, the model of direct drive turntable system for permanent magnet ring torque motor is simulated using MATLAB/SIMULINK software. The simulation results indicated that the designed controller which combined the dynamic integral sliding mode control method and adaptive H∞robust control policy can estimate the system parameters effectively; meanwhile it has minimal steady-state error and stronger robustness, and it can also achieve high-precision positioning for angular displacement signal of system, compared with the traditional integral sliding mode control method,the strategy proposed in this paper can make the direct drive servo system have strong robustness,excellent performance of localization, thus improves the servo performance of system.