Application Cases

Experiment Name: Experimental Study on Reaction Force Compensation Elimination of PFSM

Experiment Purpose: This paper mainly introduces the 320mm aperture PFSM equipped with a reaction force compensation system. By building a PFSM performance parameter and reaction force test experimental platform before and after compensation, related experimental studies have been carried out based on the dynamic coupling characteristics of PFSM reaction force and compensation elimination. The PFSM performance parameter experimental results show that the designed 320mm aperture PFSM with a reaction force compensation system meets the design index requirements.

Testing Equipment: High-voltage amplifier, position sensing amplifier, oscilloscope, electronic autocollimator, and control system, etc.

Experiment Process:

The PFSM reaction force test experimental platform is built, and the testing principle of the reaction force compensation system's elimination effect on PFSM reaction force is shown in Figure 1 below.

Figure 1: Schematic Diagram of Reaction Force Compensation Elimination Test for 320mm PFSM

Under the working conditions of a driving voltage amplitude of 500V and driving frequencies of 50Hz, 80Hz, 100Hz, and 120Hz, the amplitudes of the residual reaction forces after compensation are 3.69N, 5.14N, 8.04N, and 11.13N, respectively. The reaction force elimination ratios are 82%, 90.45%, 89.78%, and 90.14%, respectively. The comparison of reaction force data before and after compensation elimination is shown in Figure 2. Figures 2(a) to 2(d) sequentially represent the comparison of reaction forces before and after compensation under the working conditions of driving frequencies of 50Hz, 80Hz, 100Hz, and 120Hz. The legend "Initial Reaction Force" represents the reaction force data before compensation, and the legend "Reaction Force after Compensation" represents the reaction force data value after compensation elimination.

Figure 2: Comparison of Reaction Force Test Results Before and After Compensation Under Different Driving Frequency Conditions

Experimental Results:

Figure 3: Local Magnification Comparison of Reaction Force Test Results Before and After Compensation

The local magnification comparison of reaction forces under driving frequency conditions of 80Hz and 100Hz is shown in Figure 3. The differences between the experimental tests and the reaction force compensation elimination ratios calculated based on the piezoelectric coupling theory FE are 17% (@50Hz), 4.95% (@80Hz), 4.825 (@100Hz), and 3.96% (@120Hz), respectively. Under low-frequency driving conditions, there is a significant difference between the experimental tests and the FE-calculated reaction force compensation effects, mainly because the residual reaction force amplitude after compensation is small, and there is a significant coupling interference with the background noise reaction force of the dynamic force sensor in the reaction force measurement system. As the driving frequency increases, the residual reaction force amplitude obtained from the test increases, and the coupling interference of the dynamic sensor background noise on the reaction force decreases, making the reaction force compensation elimination ratios from experimental tests and FE calculations basically the same. The slight differences between experimental tests and FE calculations under high-frequency driving conditions are mainly due to processing accuracy errors in the mirror device and the central flexible hinge of the reaction force compensation system, differences in actuator manufacturing, and assembly errors.

The reaction force compensation experimental test results show that the reaction force compensation system can effectively eliminate the reaction force of the PFSM. Therefore, the designed large-aperture PFSM reaction force compensation structure is effective, and the established reaction force compensation dynamic balance condition is correct.

Voltage Amplifier Recommendation: ATA-2161

Figure: Specification Parameters of the ATA-2161 High-Voltage Amplifier

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