Motion Transfer Control From Walking to Brachiation Through Vertical Ladder Climbing for a Multi-Locomotion Robot

This paper describes a motion control approach to transfer locomotion types of a multi-locomotion robot (MLR) from walking to brachiation for maneuver performance. Brachiation is a form of arboreal locomotion in which a primate swings its body like a pendulum to transfer from a tree limb to another using its arms. In addition to multiple types of locomotion, such as biped walking, quadruped walking, and climbing a vertical ladder, the MLR performs brachiation on the horizontal ladder. The vertical ladder is used as a tool for the MLR to approach a horizontal ladder from walking on a floor. Two transition motions to transfer from waking to climbing and from climbing to brachiation are designed based on the changed environmental boundaries. In addition, a motion transfer control algorithm with grasp failure recovery is proposed by considering the reaction force and torques of robot joints. Parameters about the body positions and joint torques in the motion transfer control algorithm are set to tolerate relative position errors between the robot and its environments such as the rungs of the ladder. The proposed control method for the designed motions with error correction is experimentally verified.