In order to improve the elderly people's quality of life,supporting their walking behaviors is a promising technology.Therefore,based on one ultrasonic motor,a wire-driven series elastic mechanism for walking assi...In order to improve the elderly people's quality of life,supporting their walking behaviors is a promising technology.Therefore,based on one ultrasonic motor,a wire-driven series elastic mechanism for walking assistive system is proposed and investigated in this research.In contrast to tradition,it innovatively utilizes an ultrasonic motor and a wire-driven series elastic mechanism to achieve superior system performances in aspects of simple structure,high torque/weight ratio,quiet operation,quick response,favorable electromagnetic compatibility,strong shock resistance,better safety,and accurately stable force control.The proposed device is mainly composed of an ultrasonic motor,a linear spring,a steel wire,four pulleys and one rotating part.To overcome the ultrasonic motor's insufficient output torque,a steel wire and pulleys are smartly combined to directly magnify the torque instead of using a conventional gear reducer.Among the pulleys,there is one tailored pulley playing an important role to keep the reduction ratio as 4.5 constantly.Meanwhile,the prototype is manufactured and its actual performance is verified by experimental results.In a one-second operating cycle,it only takes 86 ms for this mechanism to output an assistive torque of 1.6 N·m.At this torque,the ultrasonic motor's speed is around 4.1 rad/s.Moreover,experiments with different operation periods have been conducted for different application scenarios.This study provides a useful idea for the application of ultrasonic motor in walking assistance system.展开更多
An adaptive series speed control system for an interior permanent magnet synchronous motor(IPMSM)drive is presented in this paper.This control system consists of a current and a speed control loop,and it is intended t...An adaptive series speed control system for an interior permanent magnet synchronous motor(IPMSM)drive is presented in this paper.This control system consists of a current and a speed control loop,and it is intended to improve the drive’s speed tracking performance as well as to compensate for voltage distortions caused by non-ideal characteristics of the drive’s actuator,which is a voltage source inverter(VSI).To achieve these goals,a simple model that captures these characteristics of the VSI is developed and embedded in the motor’s electrical model.Then,based on the resulting model,an adaptive proportional-integral(PI)control for the current loops is designed,allowing for state regulation and actuator compensation.Additionally,to improve the drive’s speed tracking performance,a proportional-model-reference adaptive controller(MRAC)is designed for the speed loop.Techniques from machine learning are used for designing the MRAC to effectively address nonlinearities and uncertainties in the speed dynamic.Finally,simulation results are presented to illustrate the outstanding performance of the proposed multi-loop controller.展开更多
基金Supported by China Scholarship Council(Grant No.202006830033),Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)of China.
文摘In order to improve the elderly people's quality of life,supporting their walking behaviors is a promising technology.Therefore,based on one ultrasonic motor,a wire-driven series elastic mechanism for walking assistive system is proposed and investigated in this research.In contrast to tradition,it innovatively utilizes an ultrasonic motor and a wire-driven series elastic mechanism to achieve superior system performances in aspects of simple structure,high torque/weight ratio,quiet operation,quick response,favorable electromagnetic compatibility,strong shock resistance,better safety,and accurately stable force control.The proposed device is mainly composed of an ultrasonic motor,a linear spring,a steel wire,four pulleys and one rotating part.To overcome the ultrasonic motor's insufficient output torque,a steel wire and pulleys are smartly combined to directly magnify the torque instead of using a conventional gear reducer.Among the pulleys,there is one tailored pulley playing an important role to keep the reduction ratio as 4.5 constantly.Meanwhile,the prototype is manufactured and its actual performance is verified by experimental results.In a one-second operating cycle,it only takes 86 ms for this mechanism to output an assistive torque of 1.6 N·m.At this torque,the ultrasonic motor's speed is around 4.1 rad/s.Moreover,experiments with different operation periods have been conducted for different application scenarios.This study provides a useful idea for the application of ultrasonic motor in walking assistance system.
文摘An adaptive series speed control system for an interior permanent magnet synchronous motor(IPMSM)drive is presented in this paper.This control system consists of a current and a speed control loop,and it is intended to improve the drive’s speed tracking performance as well as to compensate for voltage distortions caused by non-ideal characteristics of the drive’s actuator,which is a voltage source inverter(VSI).To achieve these goals,a simple model that captures these characteristics of the VSI is developed and embedded in the motor’s electrical model.Then,based on the resulting model,an adaptive proportional-integral(PI)control for the current loops is designed,allowing for state regulation and actuator compensation.Additionally,to improve the drive’s speed tracking performance,a proportional-model-reference adaptive controller(MRAC)is designed for the speed loop.Techniques from machine learning are used for designing the MRAC to effectively address nonlinearities and uncertainties in the speed dynamic.Finally,simulation results are presented to illustrate the outstanding performance of the proposed multi-loop controller.
