Abstract：In order to reduce energy consumption of the robot moving on the overhead line, a robot pitching joint based on parallelogram mechanism is proposed from the perspective of structure design, which is driven by a motor and flexible cables. Firstly, the joint force and energy consumption analysis is executed concerning the friction factor. The energy consumption calculating methods of the proposed joints and the traditional joints are separately presented. Then, the energy consumption characteristics are analyzed comparatively between the proposed joints and the traditional joints, in aspects of the pitching motion of multi-unit serial robots, and the obstacle-crossing motion of a robot moving on the overhead line. The simulation analysis shows that the robot based on the proposed joint can save 39.4% energy when completing the obstacle crossing action on an overhead line. Experiments are carried out on the self-built joint prototype, and the average difference of joint driving current in different load positions is less than 0.7 mA. The simulation and experimental results show that the friction energy consumption has a tiny influence on the total joint driving energy consumption, and the motion energy consumption for the joint to drive a load in pitching actions is only related to the equivalent gravity acting on the joint structure from the joint itself and the load. The designed joint has a characteristic of low energy consumption, and the farther the distance between the load and joint itself is, the more obvious the energy saving effect is, compared with the traditional pitching joint.
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