A novel parallel and self-adaptive underactuated finger with link-wheel mechanism

This paper introduces in detail a novel parallel and self-adaptive underactuated finger with link-wheel mechanism (the PASA finger). The PASA finger uses one actuator to control two joints and executes different grasping modes depending on the state of objects. Combining the advantages of other self-adaptive underactuated fingers and traditional industrial grippers, the PASA finger can both execute an enveloping grasp and a parallel pinching grasp. Geometry, static equilibrium and envelope space analysis show the impact of axis distance on contact forces distribution, and give the switch condition of pinching grasp and enveloping grasp. This paper provides methods to optimize the force distribution, the enveloping space and grasping stability of the PASA finger. Because of its strong grasping adaptability and high grasping stability, the PASA finger is suitable for industrial applications.