Research On Sensorless Control Strategy Of Electromechanical Toroidal Driv

The electromechanical toroidal drive system is a new compound drive system,which integrates the characteristics of toroidal planetary worm drive and permanent magnet synchronous motor.It skillfully combines the prime mover and reducer structure.It has the advantages of large transmission ratio range,compact structure,stable operation,high efficiency and no friction.In this paper,the mathematical model,steady-state and dynamic characteristics,terminal sliding mode control,design of sliding mode observer and extended Kalman filter and control experiment of the electromechanical toroidal drive system are deeply studied.According to the special space structure of the electromechanical toroidal drive system,combined with the influence of the revolution and rotation of the planetary,the equations of flux linkage and inductance of the drive system are derived,and the mathematical model of the system is established.On this basis,the steady-state characteristics of the drive system are analyzed.The dynamic characteristics of the system are analyzed by using state space method.The output performance of the electromechanical toroidal drive system fluctuates periodically due to the influence of planetary gear rotation.In order to weaken the periodic fluctuation of system output performance,the parameter tuning of the PI controller is completed by used the concept of active damping,and the PI-based vector control system is designed.On this basis,the closed-loop feedback rotor position is introduced into the controller,and the terminal sliding mode controller based on timevarying parameters is designed.Through the simulation and comparison analysis of the two control methods,the results show that the controller can effectively weaken the periodic fluctuation of the output performance.Based on the terminal sliding mode control,in order to solve the drawbacks of mechanical sensors and further highlight the compact structure of the electromechanical toroidal drive system,sliding mode observer based on the time-varying parameters of the drive system is designed.Through the simulation experiment of the position sensorless control system,it is found that the estimation error of the sliding mode observer is relatively large due to the influence of the time-varying parameters.In order to further improve the control accuracy of the position sensorless control,the position sensorless control system based on the extended Kalman filter is designed.The results show that EKF can accurately estimate the speed and position of the planet carrier rotor,which effectively improves the estimation accuracy of the control system.In order to verify that the control algorithm of the electromechanical toroidal drive system is effective,the software and hardware implementation issues of the control experiment platform based on DSP are introduced in detail.Through the control experiment based on PMSM,it is verified that the DSP-based experimental platform can run correctly.The position sensorless control experiment based on the electromechanical toroidal drive system is completed.The experimental results show that the sliding mode observer algorithm of the drive system can meet the basic control requirements.