Application Cases

Experiment Name: Active Vibration Isolation Experiment

Research Direction:
An active vibration isolator based on a piezoelectric stack actuator was developed, and its active vibration isolation performance under vertical sinusoidal excitation was tested. The main research contents include:
(1) Development of an active vibration isolator based on a piezoelectric stack, using acceleration sensors as sensing elements, and construction of an experimental platform for the active vibration isolation system;
(2) Modal testing of steel beam and plate structures to verify the authenticity and reliability of the finite element model;
(3) Implementation of the MCS control algorithm as the control strategy for the active vibration isolation system, conducting experimental research on piezoelectric stack active vibration isolation, analyzing the collected vibration responses using data processing software, comparing the vibration attenuation performance with and without the piezoelectric stack isolator, verifying the isolator's effectiveness, and summarizing issues encountered during the experiment.

Test Equipment:
High-voltage amplifier, signal generator, power amplifier, vibration exciter, acceleration sensors and data acquisition system, dSPACE, piezoelectric actuator, and vibration isolation platform.

Experimental Process:

Figure 1: Schematic diagram of the active vibration isolation control experiment

Figure 1 shows the system diagram of the experiment. The main workflow is as follows:

• The signal source generates an excitation signal, which is amplified by the power amplifier and input to the vibration exciter.

• The vibration exciter applies a periodically varying force to the steel beam structure, causing it to vibrate. The vibration of the steel beam simulates environmental disturbances, and the vibration frequency represents the disturbance frequency acting on the vibration isolation platform.

• Acceleration sensors measure the vibration acceleration of the steel beam and the vibration isolation platform. The signals are processed by a charge amplifier and sent as feedback to the control system.

• The signals are converted via A/D and input to the dSPACE signal acquisition module. A control program compiled in MATLAB/Simulink calculates a low-voltage control signal, which is converted via D/A and input to the high-voltage amplifier.

• The amplified signal is applied to the piezoelectric actuator, controlling it to generate corresponding driving forces to suppress the vibration of the isolation platform, thereby achieving vibration isolation.

Experimental Results:

Figure 2: Acceleration time-history curves under 10–100 Hz harmonic excitation

Figure 2 shows the acceleration time-history curves under 10–100 Hz harmonic excitation, including the uncontrolled acceleration response and the acceleration response under MCS control. To analyze the control effect and trends, the peak root mean square (RMS) of acceleration under uncontrolled, rubber isolation, and MCS control conditions were compared, and corresponding acceleration trend diagrams (Figure 3a) and acceleration level diagrams (Figure 3b) were plotted.

Figure 3: Acceleration amplitude-frequency curves at the target position

Analysis of the vibration responses with three types of isolation devices shows that:

• Rubber isolation pads fail to provide vibration isolation in the 10–100 Hz frequency range. Instead, the acceleration response is significantly amplified near the natural frequencies of the beam-plate structure (20 Hz, 50 Hz, and 70 Hz), indicating the failure of simple passive isolation at low frequencies.

• MCS control demonstrates significant vibration isolation effects in this frequency range, achieving up to 22.0% vibration attenuation.

Specific results include:

• At 20 Hz external disturbance: The uncontrolled acceleration RMS is 1.36 m/s², reduced to 1.14 m/s² under MCS control, achieving a 16.1% reduction in amplitude.

• At 50 Hz external disturbance: The uncontrolled acceleration RMS is 3.97 m/s², reduced to 3.09 m/s² under MCS control, achieving a 22.0% reduction in amplitude.

• At 70 Hz external disturbance: The uncontrolled acceleration RMS is 8.42 m/s², reduced to 6.91 m/s² under MCS control, achieving an 18.9% reduction in amplitude.

• In other frequency ranges, MCS control achieves 10%–15% acceleration amplitude attenuation, proving its effectiveness in reducing the acceleration of the beam-plate structure under external excitation.

  
  

Figure 4: Acceleration time-history curves under white noise excitation

Figure 4 shows the acceleration time-history curves under white noise excitation for uncontrolled and MCS-controlled conditions. Since random white noise signals easily excite the modal responses of the beam-plate structure, MCS control significantly attenuates the acceleration response by approximately 30%, demonstrating notable vibration control effectiveness.

High-Voltage Amplifier Recommendation: ATA-2168

Figure: ATA-2168 High-Voltage Amplifier Specifications

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