## 2 Research Status of Key Technology for Environmental Perception of Intelligent Excavators
### Research Status of LiDAR Vibration Reduction Technology  
To collect excavator vibration data in real time, [PERSON] et al. [23] designed an excavator vibration monitoring recorder with an STM32F103 microcontroller as the core. [PERSON] et al. [24] used wavelet packet band energy decomposition and Hilbert-Huang transform, respectively, to study the noise reduction methods of vibration signals in the process of excavator shoveling. The research shows that the reconstructed vibration signals based on the Hilbert-Huang transform can better reflect the essential characteristics of real vibration signals. [PERSON] et al. [25] established the finite element model of the excavator cab mechanism, conducted modal analysis on the noise and vibration characteristics of the excavator cab, and optimized the cab structure based on the analysis results, effectively reducing the vibration and noise. [PERSON] et al. [26] studied the vibration characteristics of the lifting mechanism of excavators and obtained the reasonable vibration range of the lifting mechanism through experimental analysis. The above studies are all aimed at the vibration analysis of the excavator itself. However, compared with traditional excavators, intelligent excavators need to use LiDAR for environmental perception, and vibration has a greater impact on environmental perception accuracy. Therefore, the research of LiDAR vibration reduction technology is of great importance to intelligent excavators. At present, research on the LiDAR vibration reduction technology of intelligent excavators is still limited. However, there is a solid research foundation in related fields such as unmanned and aerospace vehicles, which can play a certain role in the research of LiDAR vibration reduction for intelligent excavators. These studies are mainly divided into two types. Figure 5: Key technologies of environmental perception under complex working conditions. In terms of software, vibration theory analysis or simulation studies of the LiDAR detection process under vibration conditions are conducted. A response model is established between the LiDAR measurement data and vibrations, enabling compensation and correction of measurement data affected by vibration. 2. In terms of hardware, the main vibration parameters, such as amplitude and frequency, are measured through experiments, and the vibration patterns are analyzed. Then, a vibration-damping platform is designed, and an optimal installation position is selected, effectively reducing the impact of vibration on the LiDAR. In terms of software, [PERSON] et al. [27] proposed a simulation method to evaluate the impact of vibration error on the scanning accuracy of LiDAR. The research shows that the vibration of LiDAR platforms seriously reduces the position accuracy of the point cloud, and the position accuracy error caused by vibration is relatively complex, and cannot be fitted with a simple polynomial function. [PERSON] et al. [28] proposed a method based on trajectory dual-detector interferometry to estimate and compensate LiDAR phase errors caused by platform vibration. [PERSON] et al. [29] proposed a new LiDAR vibration estimation method to solve the problem of large vibration estimation error under the conditions of wide azimuth beam and low SNR. [PERSON] et al. [30] analyzed the working principle and corresponding vibration of vehicle-mounted three-dimensional scanning LiDAR to solve the problem of ranging accuracy error caused by road impact and vibration, established a mathematical model between shock and vibration excitation and circuit vibration and noise response, and proposed a vibration and noise elimination method based on wavelet analysis. [PERSON] et al.