Research On Long Life Type High Precision Linear Positioning System Based On Traveling Wave Ultrasonic Motor

The traveling wave ultrasonic motor is a new type of non-electromagnetic motor,its structure and operation principle are very different from the former electromagnetic motor.The traveling wave ultrasonic motor is accomplished by the inverse piezoelectric effect of piezoelectric materials to complete the energy conversion,relying on the friction between stator and rotor coupling to transfer driving force,drive actuator operation.The micro motor has the advantages of high precision,resistance to harsh environment,large torque,self-locking capability and other advantages,so it is widely applied in the field of industrial control,precision positioning system,camera automatic focusing in real life.However,because the ultrasonic motor is driven by the friction coupling between the stator and the rotor,friction will inevitably bring losses,leading to shorten his life,the general effective working time is less than 1000 hours,therefore,it is limited to some extent in the practical application.In order to overcome the shortcomings of the short life of the traveling wave ultrasonic motor,a new method for the driving of the hybrid traveling wave ultrasonic motor is presented in this paper.The high positioning accuracy of traveling wave ultrasonic motor is combined with the advantages of long service life of stepping motor,a kind of composite traveling wave ultrasonic motor with high positioning precision and long service life is designed.The composite traveling wave ultrasonic motor integrates the advantages of the traveling wave ultrasonic motor and the step motor,at the same time overcome the shortcomings of the two motors,both the precision of the linear positioning system is improved and the service life of the ultrasonic motor is prolonged.In this paper,a linear positioning system is made to verify the long life type high precision characteristics of the hybrid traveling wave ultrasonic motor.The linear positioning control system is composed of a linear guide rail,a grating ruler,a digital display meter,a compound type traveling wave ultrasonic motor,a STM32 and a peripheral circuit.The control strategy for the positioning process of the whole linear positioning system is: the anterior segment is controlled by the stepper motor,the final segment is controlled by the traveling wave ultrasonic motor.Through the combined control strategy in prolong the use time of traveling wave ultrasonic motor at the same time,realized the high precision positioning control.