Application Cases

Experiment Name: Electrostatic Levitation Device Control Algorithm and Levitation Experiment

Research Direction: To achieve stable levitation, heating, and temperature measurement of material samples, the electrostatic levitation experimental system integrates complex opto-electromechanical peripheral equipment such as photoelectric sensors, temperature measuring instruments, lasers, CCD cameras, and stepper motors. During the experiment, multiple engineering parameters must be dynamically adjusted, and scientific data must be collected and analyzed in real time. To this end, a comprehensive monitoring software has been developed, integrating functions such as process control, parameter configuration, data storage, and viewing, thereby enhancing the convenience and automation of experimental operations.

Test Equipment: High-voltage amplifier, photoelectric sensor, temperature measuring instrument, detector, etc.

Figure 1: Electrostatic Levitation Position Control Model

Experimental Process:
Stable control of the sample’s levitation position is the core of electrostatic levitation technology. The levitation process includes three stages: sample charging, detachment from the electrode plate, and stable levitation. The experimental challenges are as follows:

• The sample diameter is only 2 mm and must be levitated between electrode plates spaced 8 mm apart. After stabilization, the sample is only 3 mm away from the upper and lower plates, requiring extremely high precision in position measurement.

• Without control, the sample could collide from the lower plate to the upper plate within 10 ms, necessitating an extremely short control cycle.

• During initial levitation, the sample is subjected to the mirroring gravitational force from the lower plate, which may cause rapid ascent after detachment, increasing the complexity of the control algorithm.

The levitation control system model is shown in Figure 1. The PSD sensor detects the sample’s position in real time as feedback, and the high-voltage amplifier adjusts the electric field intensity between the upper and lower electrodes based on the controller’s instructions, thereby controlling the sample’s levitation position. The controller uses the current feedback position signal and performs PID calculations to generate the output signal for the next moment, achieving closed-loop position control.

Experimental Results:

Figure 2: Image of the Sample in Stable Levitation

Initially placed at the center of the lower electrode plate, the sample begins to tremble slightly as the plate voltage gradually increases. When the Coulomb force overcomes the mirroring gravitational force, the sample accelerates upward. By dynamically adjusting the plate voltage through the control algorithm, the vertical position is first stabilized, followed by horizontal control to suppress oscillations. Ultimately, the sample achieves stable levitation between the electrode plates, as shown in Figure 2.

Figure 3: Position and Voltage Change Curves During Levitation

The curves of position and voltage changes during the levitation process are shown in Figure 3. The integral separation method effectively reduces overshoot during the initial levitation stage. After the sample stabilizes, control parameters are adjusted to dampen oscillations, improving the system’s dynamic response and steady-state accuracy.

Recommended High-Voltage Amplifier: ATA-7025

Figure: ATA-7025 High-Voltage Amplifier Specifications