A CFRP/PZT laminated piezoelectric motor with high force density

Abstract

This work presents a laminated piezoelectric (PZT) motor to achieve high force density, high strength, and compact structure. The oscillator consists of vibration units and a driving foot. Each of the vibration units is formed by symmetrically bonding two PZT ceramics on a carbon fiber-reinforced plastic (CFRP) layer to improve its strength. The oscillator works in hybrid mode of the first longitudinal vibration (L1) and second bending vibration (B2). The finite-element method is adopted to tune the resonance frequencies of the two modes, and the vibration characteristics are experimentally analyzed. The strength test shows that the presence of the CFRP layer can increase the overall strength of the oscillator by 28% compared with a pure PZT motor. To evaluate the performance, the load characteristics of the fabricated prototype (with a size of 39 × 10 × 4.6 mm3 and weight of 10.6 g) are tested on a designed testbed. The single-phase driving method is used to drive the motor, and the best performance is obtained at the B2-mode frequency. The maximum thrust force, no-load speed, and output power reach 17 N, 335 mm s−1, and 775 mW, respectively, at a drive voltage of 100 Vp. Meanwhile, a thrust density of 1604 N kg−1 and an output power density of 73.11 W kg−1 are achieved. The thrust density is much higher than that of the other motors that operate in the same modes.

An Ultrasonic Motor Using a Carbon-Fiber-Reinforced/Poly-Phenylene-Sulfide-Based Vibrator with Bending/Longitudinal Modes

“…USMs are basically composed of vibrators and sliders [11], with the vibrators having a fundamental effect on vibration properties [1,8,12]. In general, the vibrators incorporate piezoelectric materials and vibrating bodies [1,8,13], with the piezoelectric materials (lead zirconate titanate (PZT) in most cases) acting as excitors [1,14], and meanwhile, the vibrating bodies achieve modal degeneration (i.e., gathering the resonance frequencies of different vibration modes) and enlarge vibration amplitude [15]. Since it is not cost-efficient to use PZT plates with non-uniform shapes [16], many technicians focus on modifying vibrating bodies to decrease the weight of USMs [17,18].…”

Theoretical modeling and experimental investigation of carbon fiber reinforced plastic-based piezoelectric actuator

“…The polarization directions of PZT layers are shown in figure 1. The rectangular outer surface of the PZT layers is divided into four equal regions as positive electrodes [31], while the other surface serves as a ground electrode. The four positive electrodes are divided into two groups diagonally, as shown in figure 1, with A1 and A2 as group A, and B1 and B2 as group B.…”

“…The four positive electrodes are divided into two groups diagonally, as shown in figure 1, with A1 and A2 as group A, and B1 and B2 as group B. To simplify the excitation method of the actuator, the single-phase excitation method is employed [31]. When group A is energized, it produces clockwise elliptical motion at the driving foot, as shown in figure 2, while the opposite produces counterclockwise motion, thereby achieving bidirectional motion control of the actuator.…”

“…The material parameters of PZT layer and CFRP layer are listed in tables 1 and 2, respectively. The manufacturing method of actuators has been mentioned in our previous research [31]. The damping ratio of CFRP cannot be ignored, so we have measured the damping ratio of piezoelectric bimorph beam.…”

Research on interactions between different operating modes of piezoelectric motors

“…Nowadays, the most representative piezoelectric motors include single mode motor which exploits two bending modes with the same order number [4][5][6], and composite mode motor which utilizes two different types of vibrational modes, such as longitudinal-bending [6][7][8], longitudinal-torsional [9,10], and bending-torsional modes [11,12]. However, the working modes of existing piezoelectric motors are typically fixed and should be simultaneously excited [13][14][15][16][17][18][19][20].…”