Mechanical & Fluid Systems

Nonlinear Model Predictive Control

This whitepaper presents an automatic workflow for implementing Model Predictive Control (MPC) controllers. The process uses MapleSim to generate a model of the system, whose dynamic equations are then extracted using Maple. Next, Maple is used to formulate the MPC problem, and generate the solver, which it automatically converts into the C code of the MPC controller. The advantage of using Maple is that the required procedures and their corresponding derivatives are computed and optimized whenever there is a change in the dynamic equations. The use of Maple saves time, removes human error, and produces highly optimized controller code.

Posted in: White Papers

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Habitat Water Wall for Water, Solids, and Atmosphere Recycle and Reuse

This technology can be used in wastewater treatment plants. Ames Research Center, Moffett Field, California A method was developed that allows water recycling, air treatment, thermal control, and solid residuals treatment and recycle to be removed from the usable habitat volume and placed in the walls of a radiation-shielding water wall. This design also provides a mechanism to recover and reuse water treatment (solid) residuals to strengthen the habitat shell.

Posted in: Briefs, Recycling Technologies

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Novel Feedthrough for Instrumentation Lead Wires

John F. Kennedy Space Center, Florida This invention is a method and design for the conveyance of instrumentation lead wires from one pressure boundary to another pressure boundary in cryogenic process systems. Such a device or article is commonly referred to as a feedthrough. The novelty of the present invention is the extreme low-temperature conditions commensurate with extreme leak-tightness requirements that are managed by a relatively simple and economical approach. The design is directly applicable to any process system or instrumentation device operating below approximately 300°F. The novel feedthrough design is very cost-effective and easy to produce, yet provides solutions to sealing problems under severe conditions or for extremely demanding requirements.

Posted in: Briefs

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Pneumatic Conveying of Lunar Regolith Simulant

Closed-loop conveying may be desirable in terrestrial applications where the motive gas is scarce or expensive, such as helium. John F. Kennedy Space Center, Florida Planetary regolith (dust) is an aggregation of various minerals and different particle sizes. Collection, storage, processing, and disposal of this material are very challenging in the harsh planetary environment. Extraterrestrial operations involving In-Situ Resource Utilization (ISRU) require conveying of regolith. The regolith needs to be transported from the planetary surface to chemical/thermal reaction vessels, and spent (processed) regolith needs to be conveyed to a disposal area.

Posted in: Briefs

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Low-Cost, Portable Platform for Mounting Multiple Antennas for Automatic UAV Tracking

This continuous-rotation platform holds ~60 pounds of antennas to track any line-of-sight object carrying multiple radio frequency sources. Armstrong Flight Research Center, Edwards, California Researchers at NASA’s Armstrong Flight Research Center have developed an innovative antenna-mounting platform that addresses an unmet need in the unmanned aerial vehicle (UAV) market.

Posted in: Briefs

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'Snap' Design Mimics Venus Flytrap

A team led by physicist Christian Santangelo at the University of Massachusetts Amherst uses curved creases to give thin shells a fast, programmable snapping motion. The technique – inspired by the natural "snapping systems" like Venus flytrap leaves and hummingbird beaks – avoids the need for complicated materials and fabrication methods when creating structures with fast dynamics.

Posted in: News, Joining & Assembly

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Gear Shift Modeling and Analysis for Automatic Transmissions in MapleSim

In this paper, a simple dynamic physical model of an automatic transmission was created to evaluate all required forces and motion characteristics of the system during the shift process. Gear shift quality was assessed by setting different timing sequences for the engage/disengage process of the frictional components (pressure on the clutches), during the upshift process. The output torque of the transmission was analyzed under two conditions, with the timing to apply/remove pressure from the clutches being different in both cases.

Posted in: White Papers

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