Study On Inspection Robot Running Through The Obstacles Along The Ground Wire For Overhead Transmission Lines

Inspection robot, as an efficient tool for overhead transmission lines inspection, has become the research focus in recent years. Currently, the motion plan for obstacles negotiation is too complex for robot to cross the obstacles efficiently and safely. And the operation scale is limited by the communication distance and cruising power of battery. Those factors are the major hampers for the popular use of the inspection robot. This study aims on making the inspection robot be able to operate for a long distance under unmanned surveillance conditions. Basing on the comprehensive analysis of the environmental characteristics of phase wire and ground wire, an integrated intelligent inspection robot system has been proposed. It is composed by the reconstructed ground line environment, the inspection robot body, the solar charging station, the human-computer interaction platform and the automatic offline device. Furthermore, the major theoretical and technical problems, such as the identification and controlling of driving wheels slipping, the method of obstacle negotiation, and self-charging docking, are investigated and the key methods to solve these problems are proposed in this study. The inspection robot system and related techniques were verified on experimental lines. And the robot system was carried to operate on the field overhead transmission lines. The results of the operation showed that the inspection robot system could identify and control the slipping of the driving wheels efficiently when it runs on the straight line between the towers, go through the obstacles autonomously with high safety and efficiency, and get power supply by charging docking independently. Through the research of this study, the safety, efficiency and cruising power of the robot system are greatly improved. And the inspection robot system can not only work along the lines for a long distance automatically, but also fulfill the inspect task efficiently. The concrete research contents and innovation are as follows:1) An integrated intelligent inspection robot system constructed by the reconstructed ground line, the inspection robot body, the solar charging station, the human-computer interaction platform and the automatic offline device has been proposed and designed in this study. This system provides the platform for studying the key theoretical and technical problems, including the identification and control of driving wheels slipping, the self-charging docking, and the obstacle negotiation method. The solution of these key problems can make the long-distance inspection of robots without manual control be realistic.2) To control the driving wheels slipping problem, a self-adaptive slipping identification and control method has been proposed. Firstly, the mechanism and force situation of the robot have been analyzed when the wheel slipping happens. Then we discussed the major factors to control the robot slipping and developed a dynamic model to identify the wheel slipping. Finally, we proposed a slipping identification strategy and a fuzzy control-based slipping control method. This slipping identification and control method has been tested by the operations on the experimental lines with different angles. The experiment results indicate that the proposed method is effective to control the slipping of the driving wheels, reduce the energy loss of the robot, and improve the service life of the driving wheel. It provides the premise condition for the robot to operate with long distance.3) The major characteristics of obstacles in the overhead transmission lines have been investigated to consider the obstacle combinations as the obstacle group. Then an object-oriented control system for the robot navigating obstacles has been proposed. This system is designed based on the concept that the robot movements are combined by movements of each mechanism, which is then be wrapped as a movement unit. The navigation of the robot to cross the obstacle group can be specified as sequences of those movement units. The validity and feasibility of the proposed method are verified with the obstacles negotiation experiment on the simulation lines.4) In order to guarantee the inspection robot auto-dock with the solar charging station correctly and reliably, an auto-recharging docking control method is presented. It is based on position relation coarse positioning, visual servo precise positioning and pressure sensor joint feedback. The charging precise positioning servo control law is designed by adopting the variable universe fuzzy control method. The auto-recharging docking control way has been tested in the imitate and real routines, which proves that the method is reliable and effective, and it also can satisfy the docking demands of auto-recharging.5) The running tests for the inspection robot under unsupervised conditions in the field high voltage transmission lines up to 20km have been implemented. The operation results demonstrate the security, practicability and robustness of the inspection robot system. The images obtained by the inspection robot are clear with high resolution. There is no any blind area found when inspecting the lines, which is helpful to find the potential safety hazard. The results of the operation show that the inspection robot could not only work along the lines for a long distance automatically, but also fulfill the inspect task efficiently.