Control And Compensation Of Servo Systems With Backlash

Backlash in servomechanisms is one of the main factors reducing the tracking performance of servo systems. Ignoring its presence during control design would cause a severe deterioration of system performance which may lead to steady-state errors, oscillations and even instability. To reduce the influence of backlash on the system, compensation control of servo systems with backlash is studied in this dissertation. Firstly, different backlash models and compensation approaches are introduced.Secondly, an approximately backlash nonlinear dead-zone model is proposed, based on which backstepping integral adaptive control is put forward for a typical mechanical position servo system. The control law based on state feedback is developed with backstepping approach for selecting appropriate Lyapunov function. The purpose is to ensure global stability of servo systems with backlash and achieve a desired tracking precision. The simulation results show that the proposed method can greatly mitigate the effects of backlash, increase tracking accuracy and improve system robustness, compared with traditional PID control law.