In order to solve the parameter uncertainty of the servo system,a switching control strategy with speed as the switching signal was proposed.The nonlinear Bode diagram was obtained using the offline data of the servo motor.The speed region of the system was divided according to the change interval of the frequency domain characteristics.Taking the speed index as the switching condition,flatness algorithm was introduced into simulated annealing algorithm to identify the parameters of each subsystem,and the switched model was established,the vibration problem of the switching system was solved.Finally,based on the state observer,the controllers of each subsystem of the switched model were designed to form the feedback control strategy for any switching under given conditions.The asymptotic stability of the closed-loop switching system was guaranteed.The results show that,compared with the traditional PID,the proposed control strategy optimizes the response curve of the system,and its tracking accuracy is improved 4%.