Application Cases

【Overview】

In this study, an ultrasonic motor experimental system was built to test output performance such as rotational speed and torque under two driving modes, and to confirm whether the backup mode can meet practical application requirements.

Experiment name: Performance testing experiment of a dual-driving-mode traveling-wave rotary ultrasonic motor prototype

Research directions: Traveling-wave rotary ultrasonic motor, piezoelectric ceramic redundancy design, dual driving modes, motor reliability, finite element simulation and prototype experiments

Experimental objective: To improve the working stability of traveling-wave rotary ultrasonic motors in long-life and high-reliability scenarios, this experiment adopts a redundant backup design for the piezoelectric ceramic assembly, constructs a dual-mode structure with conventional driving and backup driving, verifies that the motor can still operate normally after the rotor is bonded with backup piezoelectric ceramics, and tests output performance such as rotational speed and torque under the two driving modes to confirm whether the backup mode can meet practical application requirements.

Test equipment:

1. Signal generator: outputs low-voltage driving signals with a specific frequency, amplitude, and phase difference, providing an excitation source for the power amplifier.

2. Power amplifier: amplifies the low-voltage driving signal to a high voltage to drive the piezoelectric ceramic to vibrate.

3. Doppler laser vibrometer: non-contact measurement of the rotor vibration mode, resonant frequency, and amplitude, verifying the simulation results.

4. Torque sensor: collects motor output torque data in real time, used to plot the torque–speed characteristic curve.

5. Data acquisition unit: synchronously collects signals such as rotational speed, torque, and voltage, enabling recording and analysis of experimental data.

6. Hysteresis brake: provides a controllable load to simulate actual working conditions, used to test the motor's performance under load.

7. Finite element simulation software: completes modal, harmonic response, and dynamic analysis of the motor, and optimizes structural parameters.

Figure 1 Schematic diagram of the experimental platform

Experimental process:

First, modal, harmonic response, and dynamic simulations of the motor were completed using ANSYS and ADINA to determine the rotor structural parameters; then a dual-driving-mode prototype was machined and assembled, and the rotor vibration mode and frequency response were tested using a Doppler vibrometer. Next, a test platform composed of a signal source, power amplifier, torque sensor, and hysteresis brake was built. Under the conventional driving mode and the backup driving mode, a 500 V driving voltage was applied respectively, and the no-load rotational speed, stall torque, and torque–speed characteristics were measured.

Experimental results:

The experiment measured a maximum no-load rotational speed of 50 r/min and a stall torque of 1.3 N·m under the conventional driving mode, and a maximum no-load rotational speed of 45 r/min and a stall torque of 1.1 N·m under the backup driving mode. The output performance of the backup mode is slightly lower than that of the conventional mode, but it can still meet the driving requirements of most application scenarios, successfully verifying the feasibility and reliability of the dual-driving redundant structure.

Product advantages of Aigtek amplifiers in this application:

1. High-voltage and high-power output — ensures the driving voltage and supports the prototype in achieving stable output under high load

2. Wide bandwidth and high linearity — precisely matches the resonant frequency of the ultrasonic motor, ensuring an objective comparison of dual-mode performance

3. Four-quadrant output and high stability — readily handles capacitive load challenges and ensures long-duration reliability testing

【Recommended product】: ATA-2000 series high-voltage amplifier

Figure: ATA-2000 series high-voltage amplifier specifications and parameters