There are a lot of noises in the low-voltage power line communication (LVPLC) channel, which seriously damages the LVPLC system. The noise in the low voltage power line can be divided into general background noise and random pulse noise. These two noises will cause serious interference to the communication process based on LVPLC, reduce the signal-to-noise ratio of LVPLC system, and the communication quality cannot meet the requirements. To ensure the communication quality, this paper uses the time-frequency peak filtering algorithm to eliminate the noise in the LVPLC in the experimental environment. Firstly, this paper studies the noise characteristics based on the measured LVPLC channel noise. Secondly, the memory noise model is established, and the time-frequency peak filtering algorithm is used to eliminate the noise. In order to analyze the denoising effect of time-frequency peak filtering algorithm, the algorithm is simulated. Finally, the application effect of the algorithm is verified by experimental test. The simulation and application results show that the time-frequency peak filtering algorithm can improve the signal-to-noise ratio by about 5 dB in the actual noise environment of LVPLC, which can adapt to the changeable environment of LVPLC channel noise, and has good noise suppression effect and good application value. The application in the solar panel data transmission system shows that the time-frequency peak filtering algorithm can meet the communication performance requirements of the laboratory, reduce the bit error rate by about 2 % under the general background noise interference, and reduce the bit error rate by about 3 % under the pulse interference environment, and improve the transmission quality of LVPLC system.

Wheeled mobile robot has good ground motion ability, fast moving speed and low energy consumption, but poor obstacle surmounting performance. In order to make the mobile robot have the motion performance in complex environments, the wheel mechanism and the wheel-leg mechanism are coupled and designed, and a deformable wheel-leg structure is designed. The mobile robot can not only move in the wheel mode, but also switch to the wheel-leg mode to adapt to the complex motion environment. The deformable wheel-leg mechanism is composed of a four-bar linkage, and the static analysis of key components is carried out in ANSYS.

A bimetallic composite pipe butt joint was prepared by automatic gas tungsten arc welding (GTAW). The microstructure and pitting properties of the joint were investigated. The results show that the microstructure of the joint is columnar crystal, columnar dendrite, and equiaxial crystal. Mo, Nb, and Cr segregate in joint and form Laves and NbC precipitates in the interdendritic. The heat-affected zone (HAZ) becomes the preferred region for pitting due to recrystallization behavior and large and continuous Laves, this was demonstrated by both immersion corrosion and electrochemical experiments. To better understand the pitting behavior of the joint, this study discusses the mechanism of passive film rupture and pitting development, and uses electrolytic corrosion by Nital to simulate the morphology of the initial corrosion pits around the Laves phase.

With the development of economy and social progress, the development of China's industrial sector is booming, and the construction of oil and gas pipelines is speeding up. The inspection and maintenance of pipelines has become the current research focus. Through the analysis of the working environment and characteristics of the existing six categories of pipeline robots, the current research status of pipeline robots is systematically expounded, and the current research difficulties of pipeline robots are summarized. The summary and analysis contents have certain reference value for the future research of pipeline robot.

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