Design and Kinematic Analysis of a Multi-Degree-of-Freedom Robotic Hand with a Linearly Actuated Thumb

This paper presents the design and kinematic analysis of an ambidextrous, multi-degree-of-freedom robotic hand with a linearly actuated 1P3R thumb. The mechanism uses one prismatic joint to reposition the thumb base, and three revolute joints to generate the thumb contact position and orientation. Conventional 4R thumb and proposed 1P3R thumb kinematic models were created using modified Denavit–Hartenberg parameters. The thumb workspace, finger-thumb overlapping workspace, and number of feasible thumb configurations at each overlapping position were quantified using uniform joint sampling and voxel-based analysis. The proposed mechanism has a smaller overall workspace and multiple finger–thumb overlap volumes compared with conventional structures. However, the proposed thumb provides more feasible configurations at the same overlapping positions for all finger pairs, demonstrating that the 1P3R mechanism can actively relocate the thumb workspace along the prismatic direction and provide greater configuration diversity at shared contact positions.