Design of a stewart platform-inspired dexterous hand for 6-DOF within-hand manipulation

In this paper, we present a novel robotic hand specifically designed for dexterous spatial manipulation. Unlike most other dexterous hand designs that attempt to mimic the kinematic structure of the human hand, the proposed mechanism instead is based on the non-anthropomorphic “hexapod” structure of the Stewart platform parallel manipulator. The hand is composed of a single “grasp” actuator connected via an underactuated differential mechanism to six prismatic actuators arranged into pairs, forming three planar, parallel mechanism fingers that replicate the kinematics of a traditional 6-degree of freedom Stewart platform when grasping an object. This configuration allows for both grasping and accurate manipulation of a range of object sizes/shapes with minimal sensing. We describe the design and fabrication of a prototype hand that incorporates these kinematics and experimentally demonstrate it performing a series of accurate translational and rotational manipulations.