This study proposes a new four-fingered robot hand mimicking tree frog's sucker-attached fingers. We introduced tree frog's bone structure, movement of its fingers (addiction/abduction, flexion/extension), and its fingertip's suction function. In addition, considering the feasibility of mimicking tree frog's fingers from engineering perspective, we improved the prototype by: i) simplifying its mechanism and control by settling the thumb opposable to the middle finger, ii) simplifying control by 2 degrees of freedom handling, one motor for flexing/extending the four fingers at once by moving the wires, and one linear actuator and linking mechanism for addicting/abducting the pointed finger and the ring finger, iii) adding 4th passive joint with suction cups and a claw on the fingertip to increase contact force from the robot hand onto the object. The experiment showed the possibility that this robot hand may grasp several types of objects, whether the object is planar or 3D shape.
