NASA and General Motors developed the Robonaut 2 (R2) a state-of-the-art, dexterous, humanoid robot capable of performing tasks in an automated fashion (or via teleoperation). The R2 hand and forearm assembly represents the cutting edge of humanoid robotics technologies. The highly modular design provides significant improvements over prior humanoid robotic hands, especially in the areas of strength, speed, sensing, and ability to approximate human grasps.
R2’s hands are highly dexterous, enabling the robot to perform ergonomically challenging tasks. The robotic humanoid lower arm design includes novel robotic finger, thumb, and wrist assemblies. A novel finger actuation system comprises an actuator, tendon, conduit, tension sensor, and terminator. The actuation system is packaged in the wrist and reduces the number of actuators, providing significant space savings. Control systems include methods for tensioning and controlling torque of the tendon-driven robotic fingers.
The R2 hand and forearm assembly is designed in a modular fashion, enabling rapid replacement of components and sub-assemblies. The finger actuation control system can operate using force- or position-based control laws. R2’s hands feature an innovative tactile system that grant the robot a sense of touch (e.g., measurement of external contact forces, shear force, and slippage of objects held in the hand) an important requirement for robots designed to perform complex tasks in an automated fashion. The tactile system is enabled by novel six degree of freedom (DoF) force torque sensors, three of which are integrated into the fingers (at the proximal, medial, and distal phalanges) and two in the thumb (medial and distal phalanges).
The dexterous hand plus forearm is a completely self-contained unit with all motors and avionics packaged inside the forearm, reducing the number of conductors required for power and communication. A calibration system ensures the sensors maintain high accuracy throughout operation. A novel grasp assist device enables reliable, autonomous interaction with a broad range of objects (e.g., tools). A particle filter-based contact state estimation performs object localization and characterization.
R2’s fingers have a top speed of more than 200 mm/sec. The applications include industrial manufacturing and maintenance, space exploration, personal assistance and caregiving, emergency services and operations in hazardous environment, as well as repetitive task automation.