Abstract : This paper addresses the characteristic of a composite ultrasonic linear motor vibrator having two natural frequencies. An ultrasonic linear motor driver with frequency tracking characteristics was designed, utilizing the frequency change of the excitation signal to change the motor's motion direction, thus achieving motion control of the ultrasonic linear motor. Keywords : Ultrasonic linear motor; Motion control; Frequency tracking; Composite materials 1 Introduction Ultrasonic motors utilize the inverse piezoelectric effect of piezoelectric ceramics and the vibration of elastic bodies to convert microscopic deformations into macroscopic motion of a rotor or slider through resonant amplification and friction coupling, possessing unique technical characteristics and broad application prospects. This paper addresses the characteristic of a composite ultrasonic linear motor vibrator having two natural frequencies. By utilizing the frequency change of the excitation signal to change the motor's motion direction, the speed control characteristics of the ultrasonic linear motor were analyzed, achieving speed control of the ultrasonic linear motor. 2 Mode Shape Analysis of the Motor Vibrator The composite ultrasonic linear motor consists of two carbon fiber reinforced plastic (CFRP) blocks and a piezoelectric ceramic (PZT) block (see Figure 1). In the CFRP, the carbon fibers are arranged in parallel unidirectional directions, with the fiber direction at an angle to the bottom surface. When an alternating voltage is applied to the piezoelectric ceramic, the vibration of the anisotropic PZT in the CFRP will excite the CFRP block to form an inclined vibration deviating from the vertical direction, as shown in Figure 2. During the vibration, the point of contact between the CFRP and the guide rail is moved by the reaction force of the guide rail surface, resulting in a microscopic stepping motion, similar to a motor. Due to the high vibration frequency of the vibrating body, the macroscopic result is a uniform linear motion. [b][align=center]For more details, please click: Motion Control of Composite Material Ultrasonic Linear Motor[/align][/b]