## 3 Results
### Comparison of Experiments  
In order to validate the effectiveness of the equivalent static load optimization model and verify whether optimization indeed shifts the dynamic characteristics of the RSS base from rigidity to flexibility, the RSS base models before and after optimization were chosen for prototyping, and an experimental setup for the RSS base-rotor system was built. Modal testing was conducted using the support plates both before and after optimization to validate the effectiveness and reliability of the optimized model and simulation. To enhance the accuracy of the test results, environmental disturbances, such as wind and vibration, were minimized, and measurements were carried out in a relatively stable environment. Every effort was made to ensure that the target was stable and unaffected by external disturbances, like wind or human movement. The experiment was carried out indoors to exclude interference from wind, wind-induced vibrations, and other weather-related factors. Additionally, the indoor environment helped minimize the impact of personnel on the experiment. Prior to taking measurements, the components of the RSS base were checked to ensure that all connections were secure. The vibration measurement instrument was then calibrated to ensure that the parameters of the laser Doppler vibrometer (LDV), such as the focal position of the laser beam and the sensitivity of the receiver, were properly calibrated. Multiple measurements at several vibration points were conducted, and the average value was taken to minimize the effects of random variations. Through repeated measurements, a more accurate determination of the target's vibration state was possible, and random disturbances were effectively excluded. The layout and connections of the experimental apparatus are depicted in Figure 8, including the following critical components: an SOPTOP laser head (Zhejiang Sunny Optical Intelligence, Yuyao City, China) (1), responsible for emitting and receiving the laser beam; an RSS base (2), equipped with a reflective film and serving as the measurement object in this study; a laser Doppler vibrometer LV-S01 control box (Zhejiang Sunny Optical Intelligence, Yuyao City, China) (3), used for data processing; a Ni USB 4431 acquisition card (NI [National Instruments Corporation], Austin, TX, USA) (4), with 24-bit resolution and a synchronous sampling rate of 102 kS/s; and a computer system with Quick SA 4.0 (5). The SOPTOP laser head was aligned with the reflective film on the RSS base. Adjustments were made to stabilize the energy of the laser head, which was then connected to the LV-S01 control box. A signal transmission line was used to connect to the Ni USB 4431 acquisition card, through which the excitation and response signals were transmitted into the card, and ultimately, another transmission line connected to the computer. Figure 7: Harmonic response analysis result plot. A laser beam was emitted by the laser Doppler vibrometer (LDV) and directed onto the reflective film on the RSS base. The LDV system receives the reflected laser. If the surface of the RSS base is moving, the frequency of the reflected light changes according to the Doppler effect: if the surface moves away from the LDV, the frequency decreases; if it moves toward the LDV, the frequency increases. This frequency shift is directly related to the velocity of the object's surface, and its displacement can be derived by integration [29; 33], as shown in Equation (7). Data processing was subsequently carried out through the control unit, and the first six natural frequencies of the RSS base were acquired using Quick SA 4.0.