Research on Low-Speed Driving Model of Ultrasonic Motor Based on Beat Traveling Wave Theory

Abstract

This paper proposes a driving method, the superimposed pulse driving method, that can make an ultrasonic motor run at a low speed. Although this method solves the periodic oscillation of speed in a traditional low-speed driving motor, it still has a small periodic fluctuation, which affects the stability of the speed. To reduce the fluctuation rate of the motor speed, the structure model and driving model of the motor are established, based on the theory of a beat traveling wave, and the motion characteristics of the particle point are analyzed in this paper. The simulation curve of the motor speed is obtained according to the stator and rotor contact model and the transfer model. The research shows that the driving method introduced in this paper causes the stator surface to generate a traveling beat wave, and the driving end of the stator generates an intermittent reciprocating vibration and drives the rotor rotation, which is the mechanism of low-speed operation when the driving method is used to drive the motor, as well as the reason for the periodic fluctuation of the motor speed. To improve the speed stability, this paper controlled the output performance of the motor by changing the two control variables—prepressure and frequency difference—and concluded that the variation trend of the average speed and speed volatility were consistent with the variation trend of the motor’s average speed determinant and the speed volatility determinant, respectively, which is verified by the velocity measurement experiment and the vibration measurement experiment. These insights lay the theoretical foundation for the velocity adjustment and stability optimization and, finally, the application of the new driving method is prospected.

Research on Fast and Precise Positioning Strategy of an Ultrasonic Motor Based on the Ultrasonic Friction Reduction Theory

“…To verify that the deviation of the theoretical displacement reservation value, ∆s olc , of FSPTTPPM is smaller than that of TPSPM, the superposition drive method [9] and the driving control by the PID controller were used to obtain five sets of different initial angular velocities, which are 0.24, 0.36, 0.72, 1.09, and 1.18 rad/s. Figure 21 To analyze the experimentally measured results shown above in detail, firstly, Δ𝛾 𝑜𝑐 was obtained from the difference between 𝛾 𝑧𝑠 and 𝛾 𝑧𝑐 in Figure 20.…”

“…With the development in the field of nanofabrication, the precision table technology is imposing increasingly higher requirements for the stroke, speed, and accuracy of precision positioning systems, with the control accuracy required to be in the micrometer or even nanometer range [1][2][3]. With their advantages of simple structure, fast response, and high positioning accuracy, ultrasonic motors meet the requirements of precision positioning [4][5][6] and have a wide range of applications in precision instruments, aerospace, robotics, and biomedicine [7][8][9][10]. The common positioning strategy in engineering is TPSPM, and based on this strategy, many scholars have adopted various control methods for positioning.…”