A report describes an interface for utilizing some of the mobility features of a mobile robot for general-purpose manipulation of tools and other objects. The robot in question, now undergoing conceptual development for use on the Moon, is the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) rover, which is designed to roll over gentle terrain or walk over rough or steep terrain. Each leg of the robot is a six-degree-of-freedom general purpose manipulator tipped by a wheel with a motor drive. The tool interface includes a square cross-section peg, equivalent to a conventional socket-wrench drive, that rotates with the wheel. The tool interface also includes a clamp that holds a tool on the peg, and a pair of fold-out cameras that provides close-up stereoscopic images of the tool and its vicinity. The field of view of the imagers is actuated by the clamp mechanism and is specific to each tool. The motor drive can power any of a variety of tools, including rotating tools for helical fasteners, drills, and such clamping tools as pliers. With the addition of a flexible coupling, it could also power another tool or remote manipulator at a short distance. The socket drive can provide very high torque and power because it is driven by the wheel motor.
This work was done by Jaret Matthews, Norman Ahmad, and Brian Wilcox of Caltech for NASA’s Jet Propulsion Laboratory. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Mechanics/Machinery category. NPO-43308
This Brief includes a Technical Support Package (TSP).
Rover Wheel-Actuated Tool Interface
(reference NPO-43308) is currently available for download from the TSP library.
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Overview
The document discusses the Rover Wheel-Actuated Tool Interface, a technological innovation developed for NASA's ATHLETE (All-Terrain Hex-Legged Extra-Terrestrial Explorer) Rover. The motivation behind this development stems from the need for each leg assembly of the rover to function as a complete general-purpose manipulator, enabling effective locomotion and manipulation in various environments. The kinematics of the rover's legs are similar to those of the PUMA manipulator, which necessitates a sophisticated tool interface to maximize their capabilities.
The solution presented in the document features a tool interface that includes a "socket drive" square peg, which rotates with the rover's wheel, and a clamp that securely holds various tools onto this socket drive. Additionally, the interface is equipped with fold-out cameras that provide stereo imagery of the worksite when a tool is in use. The design allows for the precise positioning of the cameras based on the dimensions of the tool adapter, ensuring an appropriate field of view for both small and large tools.
The novelty of this tool interface lies in its ability to leverage the existing kinematic capabilities of the ATHLETE rover's wheels-on-legs mobility system for general-purpose manipulation tasks. The socket drive is directly powered by the rover's wheel motor, allowing it to deliver high mechanical torque and power to a wide range of tools. These tools can include rotating devices for tasks like drilling or fastening, clamping tools such as pliers, and even remote tools via flexible couplings. For more complex tasks, the system can accommodate custom motorized tools that can be controlled wirelessly, enabling a variety of assembly, maintenance, or servicing functions.
The document also emphasizes the potential for a "tool holster" that could dock to the ATHLETE frame, providing a variety of tools for different tasks. This innovation not only enhances the rover's operational capabilities but also represents a significant advancement in robotic technology for exploration and maintenance in challenging environments.
Overall, the Rover Wheel-Actuated Tool Interface exemplifies NASA's commitment to developing versatile and efficient robotic systems that can perform complex tasks in extraterrestrial settings, paving the way for future exploration missions.
