Mechanical & Fluid Systems

Non-Collinear Valve Actuator

This device separates the actions of the pneumatic actuator and the spring. Marshall Space Flight Center, Alabama Typical large aerospace valves use pneumatic actuators with large return springs to define a normal state. These springs are exclusively in line with the pneumatic actuator, and therefore are forced to have the same stroke and forces. These typical systems use either a large helical spring or a stack of Bellville springs. Each is long to ensure that the forces at the end of stroke are large enough to move the valve to the normal position with some margin. This invention reconfigures the actuator through the use of either a drag-link four-bar system or a cam to separate these two motions. The spring is allowed to have larger loads with significantly short spring stack length. This eliminates the need for long housings, heavy springs, and thus reduces the mass of the flight system. This configuration can be used for commercial valve actuators. Although commercial actuators generally do not have weight limitations, the reduction of the massive spring could reduce the cost of the product.

Posted in: Mechanics, Briefs

Read More >>

Head-Mounted Display Latency Measurement Rig

This technique can be used to characterize systems for product improvement by virtual/augmented reality display manufacturers. Langley Research Center, Hampton, Virginia The device and method are used to quantify end-to-end latency of head- or helmet-mounted display with head tracking systems in a laboratory or in situ. All commercial or custom head-mounted display systems that track the user’s head for the purpose of virtual or augmented reality applications encounter positional display errors due to system latency. A basic head-mounted display (HMD) with head-tracking system is comprised of (1) a near-to-eye display, (2) the head-tracking system, (3) one or more symbology or image sources, and (4) the display/image processor. Each element, and the communication among them, contributes a portion to the total latency. HMD system latency manifests as erroneous alignment of the virtual and real surroundings as the head is slewed, and is known to induce simulator sickness and other physiological issues. Therefore, minimal system latency is a design goal to reduce these physiological symptoms. The overall latency budget is the sum of time required to measure the dynamic head position, communicate the position to the display processor, compute the scene based on the position, integrate imagery, and render the scene to the display.

Posted in: Mechanics, Briefs, TSP

Read More >>

Workspace-Safe Operation of a Force- or Impedance-Controlled Robot

This technology can be used for automatic control of a robot that may come into contact with an object or operator in its workspace. Lyndon B. Johnson Space Center, Houston, Texas Precise motion control of a robot by controlling its various robotic manipulators may be organized by the required level of task specification. The levels include object-level control, which describes the ability to control the behavior of an object held in a single or a cooperative grasp of the robot; end-effector control, which is control of the various manipulators such as robotic fingers and thumbs; and joint-level control. Collectively, the various control levels achieve the required mobility, dexterity, and work task-related functionality.

Posted in: Mechanics, Briefs, TSP

Read More >>

Cryogenic Mixing Pump with No Moving Parts

The pump is self-priming and can efficiently pump two-phase fluid. John H. Glenn Research Center, Cleveland, Ohio Refueling spacecraft in space offers tremendous benefits for increased payload capacity and reduced launch cost, but the problem of thermal stratification in long-term storage tanks presents a key challenge. To meet this challenge, a reliable, compact, lightweight, and efficient cryogenic mixing pump was developed with no moving parts. The pump uses an innovative thermodynamic process to generate fluid jets to promote fluid mixing. This thermodynamic process eliminates moving parts to generate pumping action. Inherent to its design, the pump is self-priming and can efficiently pump two-phase fluid. The device will significantly enhance the reliability of pressure control systems for storage tanks.

Posted in: Mechanics, Briefs, TSP

Read More >>

Seal Design Feature for Redundancy Verification

The technology may be of interest to designers of high-altitude aircraft and submarine vessels. Lyndon B. Johnson Space Center, Houston, Texas NASA has requirements for redundant seals to protect human-occupied cabin atmospheres, as well as fluid and gas systems in space vehicles exposed to the harsh environments. Comparable requirements have been passed down to the International Space Station (ISS) Program, and are now levied on the Orion Multi-Purpose Crew Vehicle (MPCV).

Posted in: Mechanics, Briefs

Read More >>

Dexterous Humanoid Robot

This robot can replace human workers in dangerous, life-threatening conditions. Lyndon B. Johnson Space Center, Houston, Texas A humanoid robot has been created that includes a torso, a pair of arms, a neck, and a head. The torso extends along a primary axis and presents a pair of shoulders. The pair of arms movably extends from the shoulders. Each of the arms is fully jointed. The neck movably extends from the torso along the primary axis, and has at least one neck joint. The head movably extends from the neck along the primary axis. The head has at least one head joint. The shoulders are canted toward one another at a shrug angle that is defined between each of the shoulders such that a workspace is defined between the shoulders.

Posted in: Mechanics, Briefs

Read More >>

Tethered Vehicle Control and Tracking System

Kite-like wind energy generation systems can power a generator on the ground. Langley Research Center, Hampton, Virginia This innovation can control the flight of a tethered vehicle, in an airborne wind energy (AWE) generation system, through the use of a pan-tilt platform and a visible spectrum digital camera, combined with tracking and control software running on a standard PC.

Posted in: Mechanics, Briefs, TSP

Read More >>