Abstract: In the process of target coordinate location robot inspection at power tunnel environment，the
traditional search algorithm will produce information loss，which leads to the problem that the accuracy of search
and location results is not ideal． Therefore，a conjugate search algorithm is proposed． This algorithm builds the
robot inspection model，obtains the coordinate system which reflects the robot posture，and then sets up the robot
search path through the conjugate operator programming． The robot collects real-time inspection images along the
search path and identifies target nodes in the image according to the eigenvalues． The position and posture of the
robot in the process of inspection are calculated，and the results of hand-eye calibration and spatial coordinate
measurement are combined to realize the search and coordinate positioning of robot inspection targets．
Experimental results show that the proposed conjugate search algorithm is closer to 0 in positioning EＲA
( Environmental Ｒisk Assessment) index of target location，and has better positioning accuracy than traditional
search algorithm．

Key words: electric power tunnel, robot inspection, target, locate the coordinate, conjugate search