Ladder climbing control for limb mechanism robot “ASTERISK”

A ladder climbing motion for limb mechanism robot "ASTERISK" is proposed. This robot has six legs. The upper three legs hold on the upper rung from its both sides alternately, just like pinching it. The lower three legs hold on the lower rung in the same way. Hence the robot can climb the ladder stably. Depending on the posture of the robot, when it lifts up its body, the robot automatically selects the legs supporting the robot\´s weight and distributes the weight to these legs based on their force margins. The legs which cannot support forces are controlled to always contact with the rungs so that the robot holds the ladder firmly. The advantages of proposed gait and control method are verified by the analysis of the supporting range and the torque, and by experiment on force distribution.