Abstract: Based on the working task requirements of inspection robot and the characteristics of obstacles on high voltage transmission lines, a novel dual-arm inspection robot is designed by adding the parallel flexible cable into the series-joints arm. According to the obstacle-crossing mechanism of robot and the types of obstacles on the transmission line, two representative control flows for robot obstacle-crossing are provided. The joints' stress states of the robotic arm in representative obstacle-crossing are analyzed by simulation. The simulation results show that the joints' torque of the robotic arm with flexible cable can be decreased obviously and the robotic adaptability to the surroundings of the transmission line obstacles can be improved by mixed rigid-flexible arm design.