The figure depicts a tendon-driven, three-fingered robot hand (or foot, depending on one's perspective) designed to be installed on the end of the left front leg of the six-legged robot described in the preceding article. This hand, which was undergoing development at the time of reporting the information for this article, is intended to satisfy the need for a small, lightweight mechanism that can grasp objects of various shapes (e.g., balls or cylinders of differing diameters), without need for an elaborate electronic control system or for multiple actuators. The hand also houses rudimentary sensors: the terminal optics of a fiber-optic camera are incorporated into the palm of the hand, and the housing for the optics doubles as a contact-sensor switch.
Each finger includes two links, with knucklelike joints. The knucklelike joint at the inner end of the innermost link is mounted on a base that pivots around an axis perpendicular to the joint axis, thereby allowing the finger to rotate into conformation with the object to be gripped. The three fingers are spring-biased into planes of action 120° apart, but forces and torques of contact with a gripped object overcome the spring biases, causing the finger to pivot into the aforementioned conformation.
For the sake of simplicity, the tendons that drive all three fingers are, in turn, driven by only one motor. More specifically, the motor drives a winch to which is coupled a set of tendons arranged as finger flexors. When these tendons are drawn in, the fingers close around the gripped object. For opening the fingers to release the gripped object, the fingers are equipped with a second set of spring-loaded tendons arranged as finger extensors. Each flexor tendon is connected to a spring stiffer than that of the corresponding extensor tendon; this provision prevents the full contact of one finger with the object from acting as a hard stop against the further closure of the other fingers, thereby enabling the fingers to conform to an irregularly shaped object.
This work was done by Brett Kennedy of Caltech for NASA's Jet Propulsion Laboratory.
NPO-20907
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Three-Fingered Robot Hand with Self-Adjusting Grip
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Overview
The document discusses the development of a miniature, three-fingered robot hand designed for use on a six-legged robot, as part of NASA's ongoing research and innovation in robotics. This robot hand is notable for its lightweight and compact design, which allows it to grasp objects of various shapes, such as balls and cylinders, without the need for complex electronic control systems or multiple actuators. The hand employs a tendon-driven mechanism, which simplifies its operation while maintaining functionality.
Incorporated into the palm of the hand is a fiber-optic camera, which serves dual purposes: it provides visual feedback and functions as a contact-sensor switch. This integration of rudimentary sensors enhances the hand's ability to interact with its environment, making it more versatile for various tasks.
The document also references a broader context of NASA's research initiatives, particularly in the realm of Space Solar Power (SSP). NASA has been tasked with exploring the feasibility of an orbiting SSP system that can generate power in space and transmit it to Earth-based receivers. This initiative aims to provide a sustainable energy solution without the need for significant investments in ground energy storage, highlighting the agency's commitment to innovative energy solutions.
The document includes references to specific NASA Tech Briefs and outlines the collaborative efforts of various researchers, including Gregory Scott Hickey, Brett Kennedy, and Tony Ganino, who are involved in the SSP project. The research presented is part of a larger exhibition at the Robotics 2000 conference in Albuquerque, New Mexico, showcasing intelligent mobile systems for assembly, maintenance, and operations in the context of space exploration.
Overall, the document emphasizes the importance of advancements in robotic technology and energy solutions, reflecting NASA's ongoing mission to push the boundaries of science and engineering for future space missions and sustainable energy practices. The development of the three-fingered robot hand exemplifies the innovative spirit of NASA and its commitment to creating practical solutions for complex challenges in robotics and energy generation.
