## 5 Experimental Analysis  
The touch beam with the ciliary-like body structure of the groove \(\varepsilon\) = 1 mm is taken as the experimental object. In order to determine the vibration behavior of the whole touch beam as a function of the position coordinate, the vibration modes of the touching beam were measured for various locations of the sampling point. The touch beam was driven by a sinusoidal signal with a voltage peak of 100 V. The experimental environment is shown in Figure 12.  
The experimental steps are as follows. * Fix the ciliary-like body touch beam to the bracket by the cantilever beam and tighten the screws on one side, so the other side is free. * The driving signal was supplied by an arbitrary signal generator. We then used the driving signal, which was modulated by the HFVA-42 power amplifier, to drive the touch beam. The voltage was adjusted to ~100 V and the signal frequency adjusted to the sixth-order natural frequency which was ~24,000 Hz. * There existed some error between the theoretical calculation and the experiment, so the frequency was fine-tuned between 20,000 Hz and 24,000 Hz, while continuously touching and feeling the changing state of the surface of the touch beam until it could be clearly felt that the touch beam became smooth. After debugging, the touch beam was obviously smooth when the experimental prototype was excited at the frequency of ~23,200 Hz. * The laser vibrometer was mounted vertically to measure the cantilever touch beam from directly above, and the measurement data was transmitted through the acquisition card to the supporting software of the computer. On the left and right touch beam segments of the piezoelectric sheets, point-by-point measurement was performed from left to right. The waveform data displayed by the computer's companion software eZ-Analyst was continuously observed. The average amplitude of the real-time waveform of the measurement points was recorded. After several measurements, five test points with larger vibration amplitudes were obtained as shown in Figure 13. Repeat measurements for each point of the larger vibration amplitudes were then taken. The vibration waveform measured results of the five points from one measurement are shown in Figure 14. The average amplitude data of the five test points, with the position coordinates, are shown in Table 3.  
Figure 12: Testing environment of laser vibrometer. Figure 13: Five large amplitude test points in the touch beam. According to the test data in Table 3 and the test results in Figure 14, the fitting of vibration shapes under the actual measurement conditions are drawn through the tracing points. The fitting vibration shapes are compared with the theoretically calculated vibration shapes. We also adjust the excitation voltage to 200 V to repeat the above steps. Figure 15 shows the comparison of the theoretical calculation and actual measurement of vibration response of the touch beam under the excitation voltage peaks of 100 V and 200 V. From these results, the following conclusions can be drawn. * The amplitude is larger when the excitation voltage is 200 V, but the positions of the five larger vibration amplitude points under the two voltage excitations are basically the same, so increasing the excitation voltage will not change the position of the touch beam peak and valley. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Test Point** & **�⃝** & **⃝** & **⃝** & **⃝** & **⃝** \\ \hline Position coordinates (mm) & 13.25 & 29.25 & 47.25 & 74.70 & 90.75 \\ Average amplitude (m) & \(1.24\times 10^{-6}\) & \(1.24\times 10^{-6}\) & \(1.24\times 10^{-6}\) & \(1.23\times 10^{-6}\) & \(1.25\times 10^{-6}\) \\ \hline \end{tabular}
\end{table} 
Table 3: Position coordinates and average amplitude of five test points. Figure 14: Vibration waveform test results of five test points. (**a**) Waveform results of test point ⃝1; (**b**) Waveform results of test point ⃝2; (**c**) Waveform results of test point ⃝3; (**d**) Waveform results of test point ⃝4; (**e**) Waveform results of test point ⃝5.