Research On Control System Of Two Degree Of Freedom Direct Drive Induction Motor

With the rapid advancement of industrialization,the traditional single degree of freedom motor is difficult to meet the needs of industrial field.The traditional multi degree of freedom motion field needs multiple linear or rotating motors,which has many parts and difficult maintenance.The 2DoFDDIM can integrate linear,rotating and helical motion,and has simple and reliable structure.Therefore,it has become a new development trend.For the application of 2DoFDDIM,a set of high-performance control system is needed,and its accurate mathematical model is needed to study the control system.It focuses on the mathematical modeling of 2DoFDDIM and the modeling of control system.The main research contents are as follows:1.Establish the mathematical model of 2DoFDDIM.Firstly,the influence of coupling effect of 2DoFDDIM is analyzed by finite element method;Secondly,the influence of end effect of 2DoFDDIM is analyzed by analytical method;Thirdly,the parameters of the actuator circuit are calculated by using the multi-layer theory method;Finally,the prototype experimental platform is built and the experiment is carried out with dual frequency converter power supply.The calculation results of the established mathematical model and the finite element simulation results are compared with the experimental results to verify the correctness of the mathematical model.2.Establish the vector control system model of 2DoFDDIM.Firstly,based on the mathematical model of 2DoFDDIM,the decoupling link is deduced and designed again to correct the slip frequency,so as to avoid the decoupling error of vector control system caused by angle calculation error;Secondly,in order to reduce the influence of load disturbance,end effect and coupling effect disturbance on the control system,the load observer is designed for load feedforward compensation,and the sliding mode controller is designed to reduce the influence of end effect and coupling effect on the control system.The established load observer and sliding mode controller are applied to the vector control system,and the correctness and feasibility of the control algorithm are verified by simulation.3.Establish a 2DoFDDIM speed sensorless vector control system based on model reference adaptive.Firstly,the secondary flux linkage is selected as the state variable;Secondly,based on the mathematical model of 2DoFDDIM,the voltage model and current model for calculating the secondary flux of two degree of freedom direct drive induction motor are derived;Thirdly,the voltage model without the parameters to be identified is used as the reference model,and the current model with the parameters to be identified is used as the adjustable model;Finally,through the design of adaptive law,the speed and speed of the motor are observed,and finally the sensorless control of 2DoFDDIM is realized.The correctness of the sensorless system of 2DoFDDIM is verified by simulation.The results show that the mathematical model of 2DoFDDIM can reflect the effects of three-phase current asymmetry,torque / thrust reduction and speed / speed fluctuation caused by end effect and coupling effect;The sliding mode controller can reduce the speed fluctuation caused by end effect and coupling effect;The load observer can accurately observe the load torque / thrust;The model reference adaptive system has little error in observing the speed,which can meet the practical application.The research in this paper provides a reference for the design of 2DoFDDIM control system.