Low Speed Control Method Of Ac Servo System For Backstepping Control Cooperative Torque Observer

With the advent of Industry 4.0,high-performance AC servo systems have developed rapidly in the fields of defense aerospace,industrial robots and agricultural production,and have become the common concern of all fields.The low-speed performance of the AC servo system is difficult to implement and the application is very extensive.Therefore,it is widely used as a beacon indicator for high-performance AC servo system by domestic and foreign scholars and engineers.The AC servo system works at low speed and generates low-speed creeping,which not only affects low-speed performance,generates noise,but also brings hidden dangers in equipment life and reliability.Backstepping control(BC)is a control method for the uncertainty of the system,and it shows great advantages in improving the control performance of the nonlinear system.In order to improve the low-speed control performance of the servo system,the low speed control method of AC servo system for backstepping control cooperative torque observer(TOB)is studied in this paper.Firstly,the mathematical model of the PMSM and the principle of vector control are introduced.Secondly,the basic principle of the backstepping control is elaborated.The design of the backstepping controller of the AC servo system is carried out and the parameter sensitivity of the controller is analyzed.Next,for the direct measurement inconvenience of the load disturbance and the friction mathematical model lead to the problem of increasing the complexity of the the backstepping controller,the torque observer is introduced to estimate and compensate the load and friction disturbance in the system.The Juli criterion is used to analyze the stability of the torque observer,and the selection criterion of the observer gain is given.Then,for the "computational explosion" problem caused by the conventional derivation,the command filter is used instead of the conventional analytical derivation,and the filtering is performed simultaneously.The error is compensated to avoid the "computational explosion" problem caused by conventional analytical derivation and improve the low speed performance of the system.Finally,this paper uses Matlab/Simulink to simulate and verify the low speed control method of AC servo system for backstepping control cooperative torque observer.The experimental verification of the scheme is carried out on the experimental platform of AC servo system.The simulation and experimental results show that the low speed control method of AC servo system for backstepping control cooperative torque observer has better dynamic performance and anti-interference ability.While meeting the system performance indicators,it can effectively weaken the adverse effects of low-speed crawling on the low-speed operation of servo system.