Research On Resonance Suppression Of Permanent Magnet Ac Servo System Based On Active Disturbance Rejection Control

At the moment,AC servo system with a permanent magnet synchronous motor predominate among high-performance servo systems seen as critical parts of robots and premium numerical control machine tools and plays an increasingly important part in electric drive.In view of the elasticity factor of the transmission device in a permanent magnet AC servo system,its motor,transmission shaft and load shall be considered to make up a double inertia system.In a double inertia system,as the bandwidth of the servo system is continuously broadened to overlap with the system’s inherent mechanical resonance frequency,it will trigger a mechanical resonance.Concerning hazards caused by the mechanical resonance,an analysis and study are made in this paper on a resonance suppression strategy combining the active suppression method based on ADRC speedloop controller and reactive suppression method based on notch filter.First of all,an introduction is given to the principle and structure of active disturbance rejection control(hereinafter referred to as ADRC),an LADRC speedloop controller is designed for single inertia servo systems,and different controllers are analyzed regarding the stability and frequency domain characteristics,laying a foundation for application of ADRC and resonance suppression in a double inertia system.With regards to a permanent magnet AC servo system with a low-rigidity transmission device,a double inertia system model is built,wherein its characteristics and mechanical resonance mechanism are analyzed at length;three types of resonance are generalized subject to the relative position relationship between the resonance frequency and system’s bandwidth limit,based on which,a study is conducted on the resonance suppression of the traditional PI control and that of a combination of the traditional PI control and notch filter.To enhance the system performance,an LADRC speedloop controller is designed in the double inertia model of permanent magnet AC servo system,a frequency domain analysis is made on the retrofitted system into which ADRC is inserted through a detailed inference.The resonance suppression effect of each speedloop controller is verified by simulation in each chapter.To verify theoretical and simulation results,a digital permanent magnet AC servo system platform taking DSP+FPGA as its key controller is built for a contrast test on a double inertia experiment platform with a low-rigidity coupling,regarding PI controller,ADRC controller,and before and after a notch filter is added to the preceding.Test results show that the resonance suppression strategy combining the active suppression method based on LADRCspeedloop controller and reactive suppression method based on notch filter can assure the system’s dynamic performance and show significant resonance suppression effect.