Research On Robust Anti-interference Control Strategy For Permanent Magnet Synchronous Motor Based Position Servo System

The permanent magnet synchronous machine(PMSM)has advantages such as simple structure,small size,high efficiency,etc.,and is widely used in industrial applications such as manipulator drive,turret positioning device,flexible manufacturing production line,machine tool processing.In the PMSM servo drive system,there are often disturbances such as uncertain parameters,external load impact,and mechanical resonance,which will have a great impact on the control performance of servo system.In a servo position tracking control system,taking the machine tool processing as an example,these disturbances will change the motion trajectory of the tool and ultimately affect the processing quality of the workpiece.In addition to the application of machine tools,other modern industrial fields also put forward higher requirements in the accuracy and response speed of servo systems.Furthermore,the control accuracy and stability of the domestic servo system technologies still lag behind Western countries such as Japan and Germany.Therefore,the research on the anti-interference control of servo drive system has become extremely important.In this thesis,according to different transmission modes,the single-inertia servo system and two-inertia servo system are mainly investigated,and their anti-interference control strategies are consequently studied in depth respectively.The main work of this paper is as follows:(1)The mathematical model of the servo drive system is established,and the influence of parameter uncertainty,external load disturbances and mechanical resonance on the servo control system is theoretically analyzed.Based on the analysis of the single-inertia servo system model,the disturbance mechanism of the two-inertia servo system is further studied.On this basis,the influence of the load to inertia ratio and stiffness coefficient of the two-inertia servo system on the mechanical resonance is analyzed emphatically,while the theoretical research and simulation verification of three existing mechanical resonance suppression methods are also carried out.(2)Aiming at the influence of parameter uncertainty and external load disturbances on the control performance of the single-inertia servo system,a robust backstepping servo position anti-interference control method(RBC)based on a nonlinear disturbance observer(NDOB)is studied.This scheme can be used to estimate the lumped disturbances of the servo system,including the uncertainty of mechanical parameters and external load disturbances.Cooperating with the NDOB,this thesis further designs a composite RBC,which not only simplifies the design process of the traditional backstepping controller,but also overcomes the influence of the observer error and the uncertainty of the system.Finally,through the comparison experiment with the traditional PI controller,it is verified that the proposed method has higher control accuracy and response speed under the condition of uncertain parameters and external load disturbances.(3)When the anti-interference control method of a single-inertia servo system is applied to a two-inertia servo system,its anti-interference and mechanical resonance suppression capabilities will have a mismatch problem,which has certain limitations.In this regard,this thesis has proposed to use the position notch filter for the mechanical resonance suppression.At the same time,considering that the change of the mechanical parameters of the motor will cause the resonant frequency to shift,which will affect the vibration suppression ability of the position notch filter,this thesis further proposes to use an adaptive position notch filter(APNF)for online tracking the resonant frequency.This method can effectively optimize the varying parameters of the filter,and improve the adaptive suppression ability of resonance frequency.On this basis,this thesis combines the RBC strategy based on the NDOB to further optimize the control accuracy and response speed of the servo control system.Finally,through the anti-interference experiment under the two-inertia servo platform,the effectiveness and feasibility of the robust anti-interference control strategy for the position servo system proposed in this paper is experimentally verified.