Grasp analysis and optimal design of robotic fingertip for two tendon-driven fingers

In this work, we focus on building the model of optimization design of the fingertip to evaluate the best fingertip shape and determining the size range of objects grasped by fingertips steadily. We describe the effect of fingertip dimension on the stability of fingertip grasp, while other existing works mostly paid close attention to stability analysis for existing fingertip designs or prototypes. First, we elaborate on a versatile force-form analysis approach to quantifying the grasp stability by constructing a series of mathematical models under rolling constraints. Second, the best performing fingertip shape is indicated for realizing stable fingertip grasps. Next, the relations between the dimension of the fingertip, the size of objects, and the posture of the fingertip relative to a stable contact point are expressed by mathematical formulations in geometric constraints. Finally, an under-actuated gripper with two 3-link fingers is designed and performs practical experiments to demonstrate for verifying the presented analysis and models.