Application Cases

Experiment Name: Experiment and Analysis of Crawling Robot

Test Objectives: The experiment includes performance testing of the piezoelectric actuator and motion testing of the crawling robot unit segment. The performance testing of the piezoelectric actuator primarily involves collecting data on the output characteristics of the actuator under operating voltage using a laser displacement sensor. This serves to compare with theoretical analysis and verify the feasibility of the composite material processing technology applied to the piezoelectric actuator. The motion testing of the crawling robot unit segment mainly evaluates whether the piezoelectric actuator can drive the leg linkages correctly under normal operating conditions and measures the displacement response of the piezoelectric actuator under load.

Test Equipment: High-voltage amplifier, low-pass filter, piezoelectric actuator, displacement sensor, differential amplifier, etc.

Experimental Procedure:

Figure 1: Schematic Diagram of the Test Platform

The foundation of the entire system's measurement accuracy lies in placing all experimental equipment on an air-cushioned vibration isolation platform. The testing of the piezoelectric actuator is based on a specialized driving power supply that employs analog control. The power supply amplifies the applied analog signals to fully meet the rated operating voltage of the piezoelectric actuator. The measurement instrument collects displacement changes at the end of the piezoelectric actuator during operation using a laser displacement sensor and transmits the data to a computer for processing.

During the experiment, the actuator receives two signal inputs: one is a high-voltage direct current, and the other is an alternating current control signal. A three-channel piezoelectric ceramic driving power supply is used to simulate and amplify the voltage. The displacement sensor collects relevant data and transmits it to the acquisition card, allowing the host computer to display the relationship between the output displacement of the piezoelectric actuator and the voltage signal in real-time.

The testing of the displacement at the end of the piezoelectric actuator primarily employs a laser displacement sensor, with only one side of the actuator selected for output characteristic testing. To ensure the accuracy of the experimental results, the test is conducted on an air-cushioned vibration isolation platform. A movable platform with a clamp serves as the fixed base for the piezoelectric actuator. The middle of the piezoelectric actuator is clamped and kept horizontal. After aligning the movable platform under the laser displacement sensor, the platform is secured to the vibration isolation platform using built-in magnets. The output characteristic testing of the piezoelectric actuator is then prepared, as illustrated in Figure 1.

Experimental Results:

Figure 2: Displacement Response Curve of the Piezoelectric Actuator

In the experiment, 10 piezoelectric actuators were selected, and displacement performance tests were conducted on both sides of each, yielding corresponding driving voltage-displacement curves. Figure 2(a) shows the data curve for an entire experimental process, while Figure 2(b) displays the displacement response curve after extracting data for several cycles. Analysis of the actual data reveals that the maximum displacement at the end of the piezoelectric actuator is 1021 μm.

Figure 3: Maximum Displacement of the Piezoelectric Actuator

Figure 3 shows the maximum end displacement values of the actuators from 20 experiments. In over 80% of the 20 experiments, the maximum end displacement of the piezoelectric actuators exceeded 850 μm. However, actuators numbered 6, 8, and 16 exhibited smaller maximum end displacements, with actuator 16 approaching zero, indicating that it had failed. Possible reasons for the failure of the piezoelectric actuators include:

1. Errors in the manufacturing process that compromised the actuator's performance.

2. Misoperations during the testing phase that may have caused minor fractures in the piezoelectric ceramic, leading to irreversible damage to the actuator's performance.
   The multi-layer material processing technology for the piezoelectric actuator is relatively successful, producing a batch of high-performance actuators with a yield rate exceeding 80%. The maximum end displacement of the actuator under no-load conditions reaches approximately 1000 μm, theoretically meeting the motion requirements of the crawling robot.

High-Voltage Amplifier Recommendation: ATA-7030

Figure: ATA-7030 High-Voltage Amplifier Specifications

The experimental materials in this article were compiled and published by Xi'an Aigtek Electronics.