TacLink: A Compact Multi-Phalanx Finger with Vision-Based Tactile Sensing and Proprioception

Compared to fully-actuated robotic end-effectors, underactuated ones are generally more adaptive, robust, and cost-effective. However, state estimation for underactuated hands is usually more challenging. Vision-based tactile sen- sors, like Gelsight, can mitigate this issue by providing high- resolution tactile sensing and accurate proprioceptive sensing. As such, we present GelLink, a compact, underactuated, linkage-driven robotic finger with low-cost, high-resolution vision-based tactile sensing and proprioceptive sensing capa- bilities. In order to reduce the amount of embedded hard- ware, i.e. the cameras and motors, we optimize the linkage transmission with a planar linkage mechanism simulator and develop a planar reflection simulator to simplify the tactile sensing hardware. As a result, GelLink only requires one motor to actuate the three phalanges, and one camera to capture tactile signals along the entire finger. Overall, GelLink is a compact robotic finger that shows adaptability and robustness when performing grasping tasks. The integration of vision- based tactile sensors can significantly enhance the capabilities of underactuated fingers and potentially broaden their future usage.