Stable grasping and object reorientation with a three-fingered robotic hand

Abstract

Robotic hands able to conduct precision in-hand manipulation have become imperative for modern robotic systems. Compliant finger joints provide compliant grasping but the post-grasp orientation of an object varies. Under-actuated, robotic hands that are capable of grasping and reorienting objects are one step closer to human-like end-effectors. This paper presents a hand prototype with two under-actuated fingers embedded with tactile feedback and a fuzzy system to obtain a stable grasp, integrated to the gripper. One fully actuated robotic thumb with 3 degrees of freedom (DOF) is also presented. The integrated system evaluates tactile feedback, object orientation and thumb trajectory planning for in-hand manipulation tasks. The fuzzy logic controller was able to perform stable grasping while the tactile sensors fixed on the phalanges successfully detected the objects' changes in orientation. In conclusion the stable grasping was maintained during the object reorientation achieving the in-hand manipulation for the proposed task.