Ultrasonic Motor Transient Characteristics Of Tests And Theoretical Studies

Ultrasonic motor (USM) is one of new kind motors. It has a short history of about 20 years, and is driven by friction between stator and rotator. Now it has a wider and wider application in civil industry, like camera industry, automobile industry, etc and high-tech industry, like aerospace industry, biomedicine industry, etc because of its high torque, low speed and anti-electromagnetic interference.It has a great use especially in the micromanipulation area, in which it is always working at high frequency of conversion between on and off. So it is helpful and meaningful to study transient response of USM.Considering the different principles of M method, T method, M/T method and the characteristic of USM, we choose T method for our measurement system. We use DSP and its peripheral circuit to collect and transmit data, PC for data reception, disposing and graphics drawing. By comparing the different result got through the three ways, we analyzed the strength and weakness of each method and found out T method is the most suitable one.Through the graphics of starting characteristic of USM, we find there is a velocity fluctuation, which means USM is a second order system instead of first order system. So we have to try to find the springs and make emendation to USM's equations of motion.There're four potential springs: shaft, rotator's disk, encoder and elastic contact between rotator and stator. It's difficult and impossible for us to calculate each spring's rigidity, so we use ANSYS and MATLAB to get rid of those springs one by one. At last we find out the spring works during transient process is elastic contact between rotator and stator.After this, we make qualitative analysis of each factor that can influence USM's velocity fluctuation, which must be helpful for deeper research.