Fuzzy Backstepping Control Of A Joint Robot Driven By PMSM

The joint robot is one of the most common robots in the industrial field.In order to simplify the controller,only the dynamic model of the manipulator is considered in the traditional joint robot control.With the rapid development of the manufacturing industry in China,the high-precision control of the joint robot is required.It is necessary to consider the mathematical model of the robot's driving motor and transmission mechanism.In this paper,a two degree of freedom joint robot driven by permanent magnet synchronous motor is studied,and the trajectory tracking control scheme of joint robot is designed by combining backstepping control and fuzzy logic system.In view of the uncertainty and nonlinearity of the joint robot,the fuzzy adaptive backstepping position controller is designed.It is very flexible to select Lyapunov function and easy to combine with other control methods for backstepping control.The fuzzy logic system can estimate the nonlinear function of the system,so that the controller design does not depend on the accurate mathematical model.According to the torque current conversion,the desired current is obtained.Complex calculation of derivative of backstepping virtual control law.For the problem of complex derivative calculation of backstepping virtual control law,a tracking differentiator is designed to estimate virtual control law and reduce the complexity of controller.Combined with the vector control of permanent magnet synchronous motor,the position control of the system is designed.In order to further improve the position tracking accuracy of the control system and effectively control the convergence rate of the position error,the prescribed performance control is applied to the fuzzy adaptive backstepping control.The performance constraint of the moving trail is changed to the unconstrained system through the error transformation function.so that the position tracking error and the tracking speed of the robot converge to the given performance boundary.Based on Lyapunov stability theory,it is proved that the stability and convergence of the closed-loop system and the position tracking error can reach the prescribed performance standard.The simulation results show that the fuzzy adaptive backstepping control scheme with prescribed performance improves the position tracking accuracy of the joint robot and the response speed of the closed-loop system.Combining active disturbance rejection technology with backstepping control,a backstepping auto disturbance rejection position control scheme with prescribed performance is proposed.The extended state observer and tracking differentiator estimate unknown dynamic model and virtual control derivative term respectively.By prescribing performance control,the control accuracy and response speed of the system are improved.Through Lyapunov stability theory,it is proved that the closed-loop system can gradually converge to any small neighborhood of the origin.The simulation results show that the method has good dynamic and steady-state performance and strong anti-interference ability.In conclusion,the joint robot position control scheme driven by PMSM is designed,combining the track tracking of manipulator control and PMSM vector control.Backstepping control and fuzzy control are adopted,and tracking performance is specified.The closed-loop system can meet the specified performance requirements,and realizes fast and accurate track tracking in the ease of external interference.