TIT Hand: A Novel Thumb-Inspired Tactile Hand for Dexterous Fingertip Manipulation

Robots often interact with unstructured and cluttered environments, requiring a dexterous robotic hand that can adapt to unpredictability. In this article, we propose a 16-degree-of-freedom (DOF) thumb-inspired tactile four-finger hand (TIT hand) for high-precision dexterous fingertip manipulation, which can realize 6-DOF manipulation of the entire hand and 4-DOF control of a single finger in Cartesian space. Specifically, we design a novel 3-DOF spherical six-bar mechanism to imitate the human thumb’s carpometacarpal (CMC) joint, enabling finger flexion/extension (FE), abduction/adduction (AbAd), and pronation/supination (PS) motions. To realize active compliance interaction with objects, we equip the fingertip with a high-resolution visuotactile sensor and develop a compliance controller based on tactile feedback. Experiments show that the controller can adjust the interaction force within 0.6 s. Finally, the proposed hand is evaluated by extensive experiments, such as strength and stiffness tests, which shows that the hand has a fingertip repeatability of 0.0302 mm and a maximum grasp force of 36 N. The experimental results verify the effectiveness of this novel hand design and the robustness of the tactile-driven compliance controller.