Mechanical Components

Deflection of Stretched Circular Membrane Under Pressure

Previously reported equations are generalized to account for a stretch preload. Equations have been derived to describe the deflection of a circular membrane under both in-plane and transverse loads. More specifically, the equations describe the radial (in-plane) and perpendicular-to-the-plane deflections for the case of a circular membrane that has been stretched at its periphery with a uniform preload to keep it taut, then clamped rigidly at its periphery, and then subjected to differential pressure.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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Rock Gripper for Sampling, Mobility, Anchoring, and Manipulation

This spine/claw-based technology has applications in military robots that need to climb natural rock surfaces or caves for reconnaissance purposes, or for revealing buried explosive devices. A new gripper mechanism can be used as an end effector for a long arm that reaches out from a nearby spacecraft for a touch-and-go type of mission. The gripper would stabilize the arm and allow samples to be collected and in situ science to be done from a fixed platform. In the long term, this style of gripper could even be used as handholds for astronauts trying to move about on/near small asteroids. The prototype developed has demonstrated a 120 N gripping force, and improvements continue to be made.

Posted in: Mechanics, Mechanical Components, Briefs

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Rockballer Sample Acquisition Tool

This tool also has application in the medical industry in the removal of tissue samples or tumors from the body. It would be desirable to acquire rock and/or ice samples that extend below the surface of the parent rock or ice in extraterrestrial environments such as the Moon, Mars, comets, and asteroids. Such samples would allow measurements to be made further back into the geologic history of the rock, providing critical insight into the history of the local environment and the solar system. Such samples could also be necessary for sample return mission architectures that would acquire samples from extraterrestrial environments for return to Earth for more detailed scientific investigation.

Posted in: Mechanics, Mechanical Components, Briefs

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Ultra-Compact Transputer-Based Controller for High-Level, Multi-Axis Coordination

Features include reduction in flex wear, streamlining of robotic structures, survivability, and uniformity in handling various types of servos. The design of machines that rely on arrays of servomotors such as robotic arms, orbital platforms, and combinations of both, imposes a heavy computational burden to coordinate their actions to perform coherent tasks. For example, the robotic equivalent of a person tracing a straight line in space requires enormously complex kinematics calculations, and complexity increases with the number of servo nodes. The conventional method of executing these calculations is with a PC-style set of electronics including a powerful CPU (central processing unit) microprocessor, operating system, power supply, a number of peripherals, connectors to support each servo node, and a web of startopology wiring across the machine (including flexing joints), generally exceeding 100 conductors. In industry, the most common implementation is one or more dedicated PC cards mounted on an ISA (Industry Standard Architecture), PCI (Peripheral Component Interconnect), or VME bus. These cards provide the I/O connectors and supplement the CPU to execute the massive kinematic calculations in real time.

Posted in: Mechanics, Mechanical Components, Briefs

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Magnetically Actuated Seal

Design replaces existing pressure-actuated lift-off seals in turbopumps and eliminates low pressure drains, thereby increasing overall efficiency. This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal’s position. This system can either be an open/close type of system or an actively controlled system.

Posted in: Mechanics, Mechanical Components, Briefs

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Regolith Advanced Surface Systems Operations Robot Excavator

This design enables new ways of excavating for resources on planetary bodies. The Regolith Advanced Surface Systems Operations Robot (RASSOR) excavator robot is a teleoperated mobility platform with a space regolith excavation capability. This more compact, lightweight design (

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Hybrid Electrostatic/ Flextensional Mir ror for Lightweight, Large-Aperture, and Cr yogenic Space Telescopes

A much lighter-weight structure with higher correction range uses polymer-based membrane mirror technology. A lightweight, cryogenically capable, scalable, deformable mirror has been developed for space telescopes. This innovation makes use of polymer-based membrane mirror technology to enable large-aperture mirrors that can be easily launched and deployed. The key component of this innovation is a lightweight, large-stroke, cryogenic actuator array that combines the high degree of mirror figure control needed with a large actuator influence function. The latter aspect of the innovation allows membrane mirror figure correction with a relatively low actuator density, preserving the lightweight attributes of the system.

Posted in: Mechanics, Mechanical Components, Briefs

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