Sliding Mode Variable Structure Control Of DC Speed ​​Control System Based On DSPACE

DC motor has good starting and braking as well as speed regulating performance, it is widely used in the field of electric drive where high accuracy or quick switch between positive and negative is needed. However, conventional PI control usually leads to overshoot in DC speed regulating system, the robustness and anti-interference ability all need to be improved. Sliding mode variable structure control(SMVSC) is not sensitive to the model error and the parameter variation, and the desired control effect can be realized by changing the structure of the system. So it is applied to double-closed-loop DC speed control system and logic non-loop-current reversible speed regulating system in this paper, the experiment research study is carried out through dSPACE.Firstly, the purpose and significance of the subject research is analyzed, and then software and hardware environment of dSPACE is introduced. Moreover, the hardware platform of the system is given.Secondly, SMVSC based on exponential reaching law and nonsingular terminal sliding mode control are applied to double closed-loop DC speed control system. When automatic speed regulator(ASR) is designed into PI controller, speed response has overshoot, so SMVSC regulator based on exponential reaching law and outside disturbance observer is designed. In order to make the speed error converge to zero in limited time, linear sliding mode surface is replaced by nonlinear sliding mode surface, and the nonsingular terminal sliding mode controller is designed. Experimental results show that the two schemes can effectively remove the overshoot and improve the anti-interference ability of the system.Finally, integral sliding mode control is adopted by logic non-loop-current reversible speed regulating system. Switch performance of DC motor with proportional and integral control is poor, so integral sliding mode speed regulator is designed, and Anti-windup compensator is added to attenuate the increased overshoot and adjustment time caused by saturation item. Simulation and experimental results all show that the system not only has good positive and negative response characteristics, but also can realize quick positive/negative switch, additionally, the overshoot phenomenon can be avoided.