## 2 Research Status of Key Technology for Environmental Perception of Intelligent Excavators
### Research Status of LiDAR Vibration Reduction Technology
Distributed inertial sensors were used to capture motion signals, while strain gauges also assisted in these measurements. The sensor fusion method developed consisted of a continuous-discrete extended Kalman filter. The above methods have a certain effect on vibration reduction, but it is difficult to quantify the actual vibration situation. Table 2 summarizes the literature [23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 43; 44; 45; 46] and analyzes the research status of LiDAR vibration reduction technology. \begin{table}
\begin{tabular}{c c c c} \hline
**Literature** & **Keywords** & **Major Contribution** & **Time** \\ \hline
[23] & Vibration monitoring & To collect real-time excavator vibration data, an excavator vibration & 2019 \\  & recorder & monitoring recorder is designed. & 2019 \\ \hline
[24] & Vibration signal noise & Wavelet packet frequency band energy decomposition and Hilbert–Huang transform are used to study the vibration signal denoising method in the process of excavator shoveling. & 2013 \\ \hline
[25] & Cab vibration characteristics & The modal analysis of the noise and vibration characteristics of the excavator cab is carried out, and the cab structure is optimized to reduce the vibration and noise effectively. & 2013 \\ \hline
[26] & Vibration characteristics of the lifting mechanism & The vibration characteristics of the lifting mechanism of the excavator are studied, and the reasonable vibration range of the lifting mechanism is obtained through experimental analysis. & 2017 \\ \hline
[27] & Simulation and evaluation & The simulation method is used to evaluate the influence of vibration error on the scanning accuracy of LiDAR. & 2012 \\ \hline
[28] & Estimation and compensation & Estimation of phase error of LiDAR caused by compensated vibration based on trajectory two-detector interferometry. & 2014 \\ \hline
[29] & Vibration estimation & To solve the problem of large vibration estimation error under the condition of a wide azimuth beam and low SNR. & 2016 \\ \hline
[30] & Mathematical model, noise cancellation & The mathematical model of vibration and noise is established, and the method of vibration and noise elimination based on wavelet analysis is proposed. & 2017 \\ \hline
[31] & Vibration blur, exposure time & A random vibration fuzzy theoretical model is established to obtain the optimal exposure time satisfying the resolution. & 2011 \\ \hline
[32; 33] & Angular vibration, line vibration & The vibration is divided into angular vibration and linear vibration, and the mathematical model of angular vibration and linear vibration is established. & 2012 \\ \hline
[34] & Damping table & An aluminum alloy frame, an optical platform, and a steel wire rope damper are used to design the radar damping table. & 2013 \\ \hline
[35] & Wire rope shock absorber & The model of the anti-vibration system is established, and the structure layout and design of the steel wire rope shock absorber are selected. & 2001 \\ \hline \end{tabular}
\end{table} 
Table 2: Research status of LiDAR vibration reduction technology.