Design Of Permanent Magnet Synchronous Motor AC Servo Loading Test System For Vehicle Headlight Adjuster

As one of the important parts to ensure the safety of driving,vehicle headlight provide good lighting for drivers without dazzling.When driving at night,the change of road condition,load,braking and acceleration control will cause the change of body tilt angle,and then the beam tilting Angle of the headlight will change.By adjusting the tilt angle of the headlights,the headlight adjuster ensures that the projection height is within the appropriate range,and ensures good lighting effect and driving safety.In this paper,according to the inspection process of headlight adjuster and the requirement of automatic inspection proposed by the factory,the automatic loading test system of vehicle headlight adjuster is designed by combining upper and lower computers.The system simulates the actual working condition of the adjuster by imposing a specified load.In each control voltage stage,real-time acquisition the parameters of adjuster,and the performance is judged by comparing with the parameters in the detection scheme.Among them,how to accurately simulate the load is the key to the system design.In order to obtain accurate simulation load,this paper selects electric loading mode of Permanent Magnet Synchronous Motor(PMSM)by analyzing the advantages and disadvantages of mechanical loading,electro-hydraulic loading and electric loading mode,and combining with the characteristics of automobile headlight adjuster loading process.The overall scheme of the loading test system was formulated,and the rotary motion of the servo motor was converted into linear motion by the gear and rack transmission,thereby realizing the force loading in the horizontal direction of the adjuster.The lower computer designs the hardware circuit platform of the adjuster loading test,and completes the parameter test of the adjuster.The main components include: power supply,control voltage generating circuit,voltage and current measuring circuit,displacement measuring circuit,force measuring circuit,motor driving circuit,communication circuit.In software design,the system main program and the sub-programs of each functional module are designed based on the idea of Time-Based.It mainly includes program-controlled voltage module,load,displacement detection module,servo load control module,communication module,and on this basis to complete the automatic control of the adjuster detection process.The characteristics of each link of the simulation loading system are analyzed,and the transfer functions of each link are established respectively.On this basis,the whole mathematical model and control equation of the loading system are established.The generation of surplus force in loading process is analyzed theoretically,the compound control strategy combining feedforward compensation with fuzzy-PID feedback is adopted to restrain the surplus force.The system has been verified by MATLAB simulation and field experiments that the effect of restraining surplus force is obvious,and the accuracy of each parameter meets the loading requirement of the adjuster.