A miniature longitudinal-bending hybrid linear ultrasonic motor inspired by the planar hinged five bar mechanism.

Inspired by the double crank planar hinged five bar mechanism, a longitudinal-bending hybrid linear ultrasonic motor with compact miniature is proposed and tested. In order to realize miniaturization, it adopts a bonded-type structure. Four lead zirconate titanate (PZT) piezoelectric ceramics are distributed equally into two groups and bonded to the two ends of the metal frame, and then, two voltages with a phase difference of 90° are applied to each of the two groups of PZT ceramics. Subsequently, the first-order longitudinal vibration and second-order bending vibration generated by the motor combine with each other at the tip of the driving foot to form an elliptical motion trajectory. According to the theoretical kinematic analysis of the free beam, the initial structural dimensions of the motor were designed. Then, the initial dimensions of the motor were optimized, and the zero-order optimization algorithm was used to achieve the purpose of longitudinal and bending resonance of the motor, and finally, the optimal dimensions of the motor were obtained. A prototype of the designed motor was made, followed by experimental tests on the performance of the prototype, including mechanical output. The maximum motor speed without load at 69.4 kHz is 134.57 mm s-1. Under 200 Vpp voltage and 6 N preload, the output thrust of the motor is about 0.4 N at the maximum. The actual mass of the motor is about 1.6 g; therefore, the thrust-to-weight ratio was calculated as 25.

A novel thin single-phase drive linear ultrasonic motor.

A novel thin single-phase drive linear ultrasonic motor is proposed and tested in this paper. The proposed motor exhibits bidirectional driving via switching between the right-driving vibration mode (RD mode) and the left-driving vibration mode (LD mode). The structure and working principle of the motor are analyzed. Next, the finite element model of the motor is established and the dynamic performance is analyzed. A prototype motor is then fabricated, and its vibration characteristics are established via impedance testing. Finally, an experimental platform is built and the mechanical characteristics of the motor are experimentally investigated. The maximum no-load speed of the motor is ∼159.7 mm/s. With 8 N preload and 200 V voltage, the maximum thrust force of the motor in the RD and LD modes are ∼2.5 and 2.1 N, respectively. The motor possesses the advantages of being light in weight and thin structure and exhibiting an excellent performance. This work presents a new concept for the construction of ultrasonic actuators with bidirectional driving capacity.