Design of Humanoid Robotic Hand Based on Link Underactuation

Humanoid robotic hands have become a research spot due to their resemblance to human hands and their strong grasping adaptability. This work presents a design of a humanoid robotic hand capable of complex grasping using underactuated linkages. The structure design of the robotic hand is described in detailed: the robotic hand has 7 degrees of freedom and 15 joints; the actuators are placed into the palm of the hand; the fingers are driven by linkages and are self-locking with worm gears. Additionally, a kinematic model is introduced to analyze the finger linkages and the fingertip forces. After that, the robotic hand built and some experiments in terms of fingertip force and grasp types were conducted. Experimental results show that the fingertip force is approximately 7.8 N in the motor blocking state, and the robotic hand shows good adaptability to different grasp types.