Application Cases

【Overview】
In this study, the Aigtek ATA-2041 high-voltage amplifier was used to build a capacitive sensor experimental system, verifying the effectiveness of a closed-loop controller based on capacitive sensor feedback in compensating for the hysteresis characteristics of piezoelectric ceramics and improving scanning angle accuracy. Ultimately, through control experiments with variable amplitude and variable frequency drive signals, the potential and practicality of this FSM (Fast Steering Mirror) in the field of beam steering technology were confirmed.

Experiment Name: Experimental Study of a Large-Angle FSM Based on Piezoelectric Actuation with Integrated Capacitive Sensors

Research Directions:

• Piezoelectric fast steering mirror (FSM)

• Input-output characteristic verification based on dynamic models

• PID closed-loop control verification based on capacitive sensor feedback

• Static and dynamic characteristic testing of the piezoelectric actuated FSM

• Verification of control effects with variable amplitude/variable frequency drive signals

Experiment Objective:
To develop a large-angle FSM prototype with integrated capacitive sensor feedback and build a corresponding experimental test system. The static and dynamic characteristics of the FSM (including scanning angle, angle step response, angular resolution, natural frequency, etc.) were tested through experiments, verifying the effectiveness of the established dynamic model in characterizing the input-output behavior of the FSM. Additionally, the effect of the closed-loop controller based on capacitive sensor feedback in compensating for the hysteresis characteristics of piezoelectric ceramics and improving scanning angle accuracy was verified. Finally, through control experiments with variable amplitude and variable frequency drive signals, the potential and practicality of this FSM in the field of beam steering technology were confirmed.

Testing Equipment:

• Voltage amplifier (Aigtek ATA-2041)

• Large-angle FSM prototype with integrated capacitive sensor feedback

• Laser Doppler vibrometer (Polytec, OFV-505/5000)

• Signal conditioning circuit

• Computer

Experimental Procedure:
First, a large-angle FSM prototype (40 mm × 40 mm × 20 mm) with integrated capacitive sensor feedback was developed, and an experimental test system was built. The capacitive sensor was calibrated. Then, static and dynamic characteristics such as scanning angle, angle step response, angular resolution, and natural frequency were tested by applying different drive signals. The validity of the dynamic model in characterizing the input-output behavior under variable amplitude and variable frequency drive signals was also verified. Finally, a PID-based closed-loop controller was constructed, and its parameters were tuned. Closed-loop control experiments were conducted with variable amplitude (sawtooth, step, square wave) and variable frequency (1 Hz, 10 Hz, 20 Hz sawtooth) drive signals. The control accuracy was quantitatively analyzed to verify the compensatory effect of closed-loop control on hysteresis and the practical potential of the FSM.

Figure 1: System Schematic Diagram

Figure 2: Experimental Platform

Experimental Results:

1. An FSM prototype measuring 40 mm × 40 mm × 20 mm was developed, and an experimental system including a laser Doppler vibrometer was built. The calibrated sensitivity of the capacitive sensor was 0.204°/mV.

2. Under 120 V drive, the maximum scanning angle of the FSM was 3.50°, the angular resolution was 10 μrad, the natural frequency was 210.7 Hz, the step response overshoot was 40.57%, and the response time was 2.2 ms.

3. The dynamic model showed good agreement with experimental results under variable amplitude and variable frequency drive signals.

4. Closed-loop control based on the PID controller effectively compensated for hysteresis. The control accuracy was better at low frequencies than at high frequencies.

   
   

Figure 3: Time Response Curves and Scanning Angle Hysteresis Loop in the Angle Experiment

Advantages of Aigtek Amplifiers in This Application:

1. High voltage output capability (400 Vp-p) – Achieves a large scanning angle of 3.50° under 120 V drive.

2. Wide bandwidth and high slew rate – Precisely matches the frequency requirements for dynamic response testing.

3. Low distortion and high output stability – Supports PID closed-loop control to effectively compensate for hysteresis and improve control accuracy.

Recommended Product: ATA-2041 High-Voltage Amplifier

Figure: ATA-2041 High-Voltage Amplifier Specifications and Parameters