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Robotics Automation and Control
Advanced Humanoid Robotic Hand Technologies
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. <i>Hand, Finger, and Wrist Assembly Design:</i> The robotic humanoid lower arm design (U.S. Patent No. 9,505,134) includes novel robotic finger (U.S. Patent No. 8,562,049), thumb (U.S. Patent No. 8,424,941), and wrist (U.S. Patent No. 8,498,741) assemblies. <i>Actuation & Control System:</i> A novel finger actuation system (U.S. Patent No. 8,467,903) – comprised of an actuator, tendon, conduit, tension sensor (U.S. Patent No. 8,371,177), and terminator – is perhaps the primary enabling technology for R2’s compact, high performance robotic hand. The actuation system is packaged in the wrist (U.S. Patent No. 8,401,700) and reduces the number of actuators, providing significant space savings. Control systems include methods for tensioning (U.S. Patent Nos. 8,412,376, 8,618,762, & 8,056,423) and controlling torque (U.S. Patent No. 8,565,918) of the tendon-driven robotic fingers. The finger actuation control system (U.S. Patent No. 8,489,239) can operate using force- or position-based control laws. <i>Tactile System:</i> 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 (U.S. Patent No. 7,784,363), three of which are integrated into the fingers (at the proximal, medial, and distal phalanges) and two in the thumb (medial and distal phalanges). A calibration system (U.S. Patent No. 8,265,792) ensures the sensors maintain high accuracy throughout operation. <i>Autonomous Grasping:</i> A novel grasp assist device (U.S. Patent No. 9,878,452 & 9,067,319) enables reliable, autonomous interaction with a broad range of objects (e.g., tools). A particle filter-based contact state estimation device (U.S. Patent No. 8,280,837) performs object localization and characterization.
robotics automation and control
Circumferential Scissor Spring Enhances Precision in Hand Controllers
The traditional scissor spring design for hand controllers has been improved upon with a circumferential spring controller mechanism that facilitates easy customization, enhanced durability, and optimum controller feedback. These advantages are partially facilitated by locating the spring to the outside of the mechanism which allows for easier spring replacement to adjust the deflection force or for maintenance. The new mechanism is comprised of two rounded blades, or cams, that pivot forward and back under operation and meet to form a circle. An expansion spring is looped around the blade perimeter and resides in a channel, providing the restoring force that returns the control stick to a neutral position. Due to the use of a longer circumferential spring, the proportion of spring expansion is smaller for a given distance of deflection, so the forces associated with the deflection remain on a more linear portion of the force deflection curve. The Circumferential Scissor Spring for Controllers is at technology readiness level (TRL) 8 (actual system completed and flight qualified through test and demonstration) and is available for patent licensing. Please note that NASA does not manufacture products itself for commercial sale.
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