NATURAL MOTION GRASPING DESIGN USING CONTROL-ORIENTED KINEMATIC MODELS

The paper explores the possibility of creating grasping devices based on a recently developed and experimentally validated control-oriented planar kinematic model for natural human hand configuration based on the geometry of a thumb-finger system, assumed to be softly enclosing the surface of a virtual cylindrical object. The model is able to calculate independently the values for the natural joint rotation angles, as well as joint velocities and accelerations of a two degrees of freedom (DOFs) thumb and a three DOFs long finger system by a single parameter, the radius of the virtual cylindrical object R. Based on the results obtained from the model, we explore the possibility of modifying the design of a four bar thumb and an eight bar index finger of the recently developed Closed Loop Articulated Wearable (CLAW) hand to enhance the wearability. The latter is done through assessing how closely the motion of the modified thumb-index finger pilot prototype resembles the thumb-index finger natural grasping motion. Future applications of the research include the synthesis and design of enhanced wearable hand devices and articulated robotic hands for natural motion.