Online Detection And Surppresion Of Mechanical Resonance For Servo System

The mechanical resonant frequency, especially after prolonged used, often variesdue to the changes of servo system characteristics or the outside environment duringoperation, making the original resonance suppression link failure. Traditional resonancemethods can not adjust the controller dynamically according to the vibration frequency.So this paper proposed a method that can online detect and suppress the mechanicalresonance for servo system. The main research includes the following several aspects:Firstly, we establish the mechanical resonance model of two-inertia servo system inthis paper. The resonant frequency expression can be derived from the model, and thecauses of mechanical resonance of the servo system can be clearly seen. Then, the papergives in-depth analysis as to the effects of the mechanical resonance for servo system.Secondly, according to the real-time requirements of servo system, this paperpresents the Sliding DFT algorithm, and compares it with traditional fast Fouriertransform. Simulation and experiment of the two methods verify that the Sliding DFT ismore effective than traditional fast Fourier transform.Then, as to online mechanical resonant suppression, this paper presents adaptivenotch filter with Sliding DFT auto searching function of vibration frequency andchanging the notch filter parameters online according to the adjust rule to reject themechanical resonant. To solve the problem that adjust the filter dynamically online tothe controller may cause the output jump of the controller, which will generate adverseimpact on the system, we propose a practical method to adjust the filter smoothly bychanging parameters gradually and discretizing filter repeatedly.Finally, we apply this method to the turntable servo system in our laboratory, andthe experimental results sufficiently show that this proposed strategy is very feasibleand effective.