A Walking Claw for Tethered Object Retrieval

Abstract

Mobility and manipulation are often considered separately, with independent degreesoffreedom (DOF) for each. However, here we show that using the legs for both walking and grasping increases the versatility of both tasks. Our robot has four DOF: drive and lift for left and right pairs of legs. The legs use a reduced actuation Klann mechanism. The lift DOF rotates the entire trajectory of the legs, which enables gait modulation, climbing, and grasping. This demonstrates the feasibility of a novel operational concept: a robot that can approach, climb onto, and securely grasp an object that can then be lifted via a loadbearing tether. Specifically, we show the kinematics to enable small robots to climb onto rectangular objects up to 67% robot height and grasp objects between 43% and 72% of the robot’s length. With these kinematics, a robot can be scaled for specific terrains and object sizes, with potential application in construction, search and rescue, and object retrieval.