Application Cases

Experiment Name: Performance Testing of Dielectric Elastomer Actuators

Research Direction:
To mitigate the butterfly hysteresis and creep characteristics in dielectric elastomer actuators, this paper proposes a novel output feedback control algorithm based on implicit inverse compensation for butterfly hysteresis with creep effects. The implicit inverse compensation algorithm is an online decoupling mechanism that derives an approximate actual control signal from the temporary control signal affected by hysteresis and creep. First, a butterfly hysteresis model with creep effects was developed for the dielectric elastomer actuator. Finally, by applying initialization techniques to set initial values in the adaptive law and virtual control signals, bounded tracking error L was achieved. Experimental validation results demonstrate the effectiveness of the proposed control scheme.

Experiment Objective:
To test the performance of the dielectric elastomer actuator and evaluate whether it can achieve the desired effect under high voltage, providing a foundation for subsequent experiments.

Test Equipment:
Dielectric elastomer film, laser displacement sensor, sensor controller, high-voltage amplifier, computer, etc.

Experimental Procedure:
Based on the fabricated dielectric elastomer actuator, a test platform was established using a laser displacement sensor, high-voltage amplifier, multifunctional input/output data acquisition card, and other equipment, as shown in the figure below.

Figure: Dielectric Elastomer Test Platform

The dielectric elastomer actuation system is described as follows:
A dielectric elastomer film was pre-stretched biaxially by a factor of 4 and fixed to a polymethyl methacrylate circular frame. Carbon conductive grease was applied on both sides of the dielectric elastomer film, with an inner diameter of 40 mm and an outer diameter of 60 mm. A PMMA load was then placed at the center of the dielectric elastomer film, where no carbon conductive grease was applied.

The experimental setup included:

• The annular dielectric elastomer actuation system

• A laser displacement sensor installed to measure the load displacement

• A sensor monitor (LK-G5001P, Keyence) connected to the laser sensor to receive measurement data

• A high-voltage amplifier that amplified the driving input signal by 1000 times

• A multifunctional input/output device for transmitting and recording input and output data

Experimental Results:
Experimental tests revealed that when the sinusoidal driving voltage amplitude exceeded 3 kV, the dielectric elastomer actuator exhibited significant deformation. Figures 2-3 to 2-5 show the deformation of the dielectric elastomer under sinusoidal driving voltages of 3.5 kV, 4.0 kV, and 4.5 kV, respectively. Based on measurements from the laser displacement sensor, the maximum electrically induced deformation of the dielectric elastomer actuator exceeded 900%.

The test results are shown in Figure 2-3. Figure 2-3(a) presents the experimental results of the dielectric elastomer actuator’s output displacement under a sinusoidal driving voltage of 3.5 kV at 1 Hz, while Figure 2-3(b) shows the input-output response of the dielectric elastomer under this driving condition. It can be observed that under sinusoidal driving voltage, the dielectric elastomer exhibits a dual-loop hysteresis phenomenon, which differs from the single-loop hysteresis observed in traditional rigid smart material actuators. Figures 2-4(a) and 2-5(a) show the experimental results of the dielectric elastomer actuator’s output displacement under sinusoidal driving voltages of 4.0 kV and 4.5 kV at 1 Hz, respectively. Figures 2-4(b) and 2-5(b) depict the input-output responses of the dielectric elastomer under these driving conditions. It is evident that the butterfly hysteresis phenomenon of the dielectric elastomer actuator exhibits nonlinear changes under driving voltages of different amplitudes.

Recommended High-Voltage Amplifier: ATA-7050 High-Voltage Amplifier

Figure: ATA-7050 High-Voltage Amplifier Specifications and Parameters