Research On Servo System With Backlash And Friction Based On Adaptive Sliding Mode Control

With the development of modern industry,the permanent magnet synchronous motor（PMSM）control has become an important part of the servo system.The traditional motor control research is limited to the motor itself,while the servo system needs a gearbox and other transmission devices.In the process of motion tracking control,the friction caused by the extrusion of the mechanical contact surface,the backlash between the gear meshing,the uncertain mismatch disturbance,and other nonlinear factors will lead to the change of load torque and have an effect on the precision of the dynamic tracking system.For the above factors,the research on the PMSM servo system models and the sliding mode algorithms with robustness has become a key research direction in the field of motor control.The main research work of the thesis,which addresses the above issues,includes:（1）Aiming at the problems of friction and parameter perturbation during the operation of PMSM position servo control,an integral sliding mode servo control algorithm based on adaptive nonlinear reaching law is designed.Considering that friction and other disturbances are concentrated disturbances,a super-twisting sliding mode observer for the compensation of the servo system is developed in real time for enhancing its robustness.An adaptive nonlinear reaching law algorithm with system state regulation performance is designed to avoid singular problems and improve the convergence characteristics of the system.（2）An adaptive backstepping sliding mode servo control algorithm with finite-time convergence is designed to solve the problems of gear backlash and mismatch disturbance during the operation of PMSM position servo control.Aiming at the gear backlash and tracking problems in the servo system,an adaptive backstepping control method is designed to improve the dynamic tracking ability of the system.An adaptive terminal sliding surface and a fixed-time reaching law with a faster convergence rate are designed,and an adaptive mechanism varying with disturbance and tracking state is introduced to offset the chattering phenomenon of the sliding mode method and improve the robustness of the algorithm.（3）A novel adaptive fixed-time sliding mode servo control algorithm is proposed to solve the problems of gear backlash,friction,and uncertain mismatch disturbance during the operation of PMSM position servo control.Aiming at the problems of friction and mismatch disturbance,a fixed-time observer is designed to enhance the anti-interference capability of the dynamic tracking system.To ensure the dynamic tracking performance of servo control,a fixed-time sliding mode surface with faster convergence characteristics is designed,and the adaptive reaching law is introduced to realize the fixed-time stability of the whole closed-loop system.In summary,the thesis investigates the servo system control problem based on the sliding mode method for the backlash and friction problems of PMSM in the motion control of the servo system,which increases the anti-interference performance and convergence characteristics of the servo system.In addition,the effectiveness of the proposed algorithm is verified by the d SPACE experimental platform.