Application Cases

Experiment Title: Dynamic Analysis of Dielectric Elastomer (DE) Materials

Testing Purpose:During the driving experiments of DE materials, in addition to static deformation, these materials are also applied in situations that require withstanding cyclic loads, such as the tail flapping of bionic fish and the forward crawling of crawling robots. Therefore, it is necessary to study the dynamic properties of the materials under alternating voltage. In the research of structural dynamic characteristics, the natural frequency is a key characteristic. The in-plane vibration of the film actuator is analyzed based on the principle of virtual work.

Testing Equipment:High Voltage Amplifier, Function Generator, Laser Sensor, Data Acquisition Card, etc.

Experiment Process:

The experimental scheme employs a biaxial stretching platform, using a rectangular DE actuator with a pre-stretch ratio of 300%*300% as the experimental object to test the deformation performance under sinusoidal voltage. First, the function generator is used to set the waveform, frequency, and other parameters of the low-voltage control signal, which is then amplified by the high voltage amplifier and applied to both sides of the rectangular actuator. The region coated with electrodes undergoes reciprocating motion under the alternating voltage, driving the auxiliary detection plate to deform synchronously. Subsequently, the displacement of the auxiliary detection plate is measured using a laser sensor, and the data is collected via a data acquisition card. Finally, the data waveform is plotted using Labview software, with a sampling frequency set at 1000Hz. Figure 2 shows the displacement output response curve of the DE actuator driven by an alternating voltage with a peak of 6000V and a frequency of 1Hz. Compared with 6000V direct current voltage, the maximum displacement output is essentially the same. As the frequency increases, the displacement gradually decreases. It can also be observed that there is a lag in the response displacement, although it is not as pronounced as under high-frequency influence. Additionally, there is a certain deviation between the peaks and troughs of the response curve, which is consistent with the simulated waveform mentioned earlier. It can be seen that it is a symmetrical curve about the trough, with a slightly sharper peak. This is mainly due to the strong nonlinearity of the DE material itself. Under high voltage, the material deformation increases, resulting in inconsistent deformation in different voltage segments.

Figure 1: Response Curve of the Actuator with 1Hz Sinusoidal Excitation Applied

Experimental Results:

Consistent with direct current voltage, increasing the voltage and pre-stretch ratio can also enhance the amplitude of the actuator. For operators that require rapid movement, such as crawling robots, the crawling speed can be increased by raising the frequency within the low-frequency range. However, it was found in the experiment that changing only the frequency without altering the amplitude has little effect on the equilibrium position of the actuator. This is mainly because the energy change per unit time is not significant in the low-frequency band.

The response characteristics of DE materials under alternating current were analyzed and studied, revealing that viscoelasticity has a severe impact on dynamic characteristics. An increase in frequency can actually reduce the amplitude due to the lagging nature of the actuator.

High Voltage Amplifier Recommendation: ATA-7100

Figure: Specifications of the ATA-7100 High Voltage Amplifier

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