Application Cases

Experiment Name: Research on IDE Piezoelectric Elements and Their Application in Bionic Wings

Research Direction: Bionics

Test Objective:
This research focuses on optimizing the structure and composition of IDE (Interdigitated Electrode) piezoelectric elements to achieve large actuation displacement and good overall performance. The study emphasizes the mechanical and electrical properties, actuation characteristics, and integration of IDE piezoelectric elements into bionic wings, as well as their control over the wing's  posture . The ultimate goal is to apply IDE piezoelectric elements to smart material structures, thereby accelerating their further practical application.

Testing Equipment:
Industrial PC, ATA-7020 high-voltage amplifier, laser interferometer, measurement system, bionic wing, control card, charge amplifier, DC power supply

Experimental Procedure:
Static experiments on the bionic wing were conducted using the measurement system, high-voltage amplifier ATA-7020, and laser interferometer, as shown in Figure A below. Five measurement points (1, 2, 3, 4, 5) were sequentially arranged on the bionic wing surface near the trailing edge along the span direction, with points 1, 2, and 3 located in the area where the MFC (Macro Fiber Composite) element was  arranged.

Figure: Static Experiment of the Bionic Wing

The maximum deformation coordinates of the measurement points were used to plot curves, as shown in Figure B above. It can be observed that as the applied voltage changes, the curve variation patterns for points 1, 2, and 3 (located in the MFC  arrangement  area) are essentially the same. The deformation capability of point 4, which is away from the MFC  arrangement  area, decreases. Point 5, located on the wing vein, exhibits even lower deformation capability. In fact, the wing membrane near the wing tip is almost  unaffected by MFC actuation. Therefore, under the action of the applied voltage, the angle of attack of the bionic wing can be controlled to a certain extent in the area where the MFC element is placed.

The motion and force generated by the flapping mechanism are transmitted to the bionic wing via a  reduction device , gear linkage structure, and connecting rod. Through the connecting rod, the bionic wing obtains the motion and force required for flapping. To detect the influence of the MFC on the aerodynamic force of the bionic wing, the method of detecting the axial stress change of the flapping mechanism's connecting rod was adopted. The flapping wing measurement and control system, shown in the figure below, consists of a host computer and a control card. The control card outputs signals to control the voltage amplifier that supplies power to the MFC and inputs signals to measure the force change on the flapping mechanism's connecting rod.

Figure: Flapping Wing Measurement and Control System

Data acquisition and control programs were written in the industrial PC using Matlab and then downloaded to the control card. After the control card, one path connects to the power amplifier to control the MFC element, and the other path connects to the charge amplifier and the PZT patch on the connecting rod surface to detect the axial force on the connecting rod. The flapping frequency was fixed at 3 Hz, and the MFC element control voltage U is shown in the table curve.

Experimental Results:
Applying different driving voltages to the MFC element, the charge variation curves of the piezoelectric patch on the connecting rod surface were measured. Using the fourth type of piezoelectric equation, the variation curves of the axial force on the connecting rod were obtained, as shown in the figure below. The results indicate that during the downstroke phase, the force on the connecting rod increases significantly due to air resistance, at which point gravity is not the dominant factor. As the applied voltage to the MFC increases, the phase of the connecting rod axial force shifts: positive voltage causes a phase advance, while negative voltage causes a relative phase lag. Furthermore, as the applied voltage to the MFC element increases, the axial force on the connecting rod increases, indicating an increase in the aerodynamic force of the bionic wing.

Figure: Influence of MFC Element on Connecting Rod Axial Force

Role of the ATA-7020 High-Voltage Amplifier in This Experiment:
To provide a controllable voltage source applied to the piezoelectric element, enabling the study of its mechanical and electrical properties, actuation characteristics, integration into the bionic wing, and control over the wing's posture .

Aigtek ATA-7020 High-Voltage Amplifier:

Figure: Specifications of the ATA-7020 High-Voltage Amplifier