Servo System's Backlash Vibration Suppression Study

The presence of backlash greatly reduces the performance of the servo system and even leads to system instability. In addition, in the system with large rotational inertia load, the existence of mechanical resonance seriously impacts on the stability of the servo system and limits system bandwidth. So it is of great importance to reduce the influences of the backlash as well as to suppress the mechanical resonance.The backlash nonlinear characteristics and mechanical resonance phenomenon of the servo system are analyzed in this paper. The control methods to eliminate the influnces of backlash and mechanical resonance are mainly studied. The main contents are concluded as follows:1) By mechanism analysis method, the dynamics models of single-motor driving system with and without backash are built and the property of backlash is studied by description function. When given different signals, the responses of the system with and without backlash are compared by simulation.2) For single-motor driving system, the control methods, including backlash inverse model compensation and angle difference feedback are studied; for dual-motor driving system, the control methods, such as angular velocity differences feedback and reduced-order model-based compensation are studied. The efficency of the methods above are indicated by simulation results.3) Aiming at the servo system with large rotational inertia load, the reason causing mechanical resonance is analyzed. For single-motor driving system, the control methods based on angular difference feedback and state feedback are studied for mechanical resonance suppression; for dual-motor driving system, the control methods based on torque feedback and state observer are studied. to suppress mechanical resonance. Simulation results indicate that the methods above are feasible.