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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 811 records · Page 45
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Fault tolerant system performance modeling

With the proliferation of complex digital systems on aircraft, the need to accurately predict system performance early in the system design cycle becomes imperative. In the past, system designers have relied on ad hoc methods for evaluating performance issues. This has produced systems that have not always worked as originally intended. To alleviate these design deficiencies, formal methods, with supporting tools, must be adhered to during the system design process. The use of performance modeling tools is becoming widely accepted as a way to address timing considerations of system design. An additional incentive for the use of these tools is that they allow the system architect to analyze system component interactions (i.e., bus contention, contention of functions for a processing site, and system repair activity on application performance). This inherent flexibility can result in an explicit specification of the system architecture. This paper addresses a method that supports performance modeling of fault tolerant systems using a discrete event simulation tool. An additional focus is on lessons learned from analyzing these classes of problems. The methodology and supporting work provide system architects with the capability to specify candidate architectures and accurately predict their performance in the early stages of design, where changes to system design is most cost effective. The work has been supported under NASA contract NAS1-18099. Integrated Airframe Propulsion Control System Architecture (IAPSA II). This contract addresses methodology, analysis, and detailed design of integrated control system architectures suitable for high-performance aircraft of the 1990's.

Discrete event simulation↗
NASA NTRS2010

Environmental Control and Life Support Integration Strategy for 6-Crew Operations

The International Space Station (ISS) crew complement has increased in size from 3 to 6 crew members. In order to support this increase in crew on ISS, the United States on-orbit Segment (USOS) has been outfitted with a suite of regenerative Environmental Control and Life Support (ECLS) hardware including an Oxygen Generation System (OGS), Waste and Hygiene Compartment (WHC), and a Water Recovery System (WRS). The WRS includes the Urine Processor Assembly (UPA) and the Water Processor Assembly (WPA). With this additional life support hardware, the ISS has achieved full redundancy in its on-orbit life support system between the t OS and Russian Segment (RS). The additional redundancy created by the Regenerative ECLS hardware creates the opportunity for independent support capabilities between segments, and for the first time since the start of ISS, the necessity to revise Life Support strategy agreements. Independent operating strategies coupled with the loss of the Space Shuttle supply and return capabilities in 2010 offer new and unique challenges. This paper will discuss the evolution of the ISS Life Support hardware strategy in support of 6-Crew on ISS, as well as the continued work that is necessary to ensure the support of crew and ISS Program objectives through the life of station

Duchesne, Stephanie M.↗
NASA NTRS2009

Environmental Control and Life Support Integration Strategy for 6-Crew Operations Stephanie Duchesne

The International Space Station (ISS) crew compliment has increased in size from 3 to 6 crew members . In order to support this increase in crew on ISS, the United States on-orbit Segment (USOS) has been outfitted with a suite of regenerative Environmental Control and Life Support (ECLS) hardware including an Oxygen Generation System(OGS), Waste and Hygiene Compartment (WHC), and a Water Recovery System (WRS). The WRS includes the Urine Processor Assembly (UPA) and the Water Processor Assembly (WPA). With this additional life support hardware, the ISS has achieved full redundancy in its on-orbit life support system between the USOS and Russian Segment (RS). The additional redundancy created by the Regenerative ECLS hardware creates the opportunity for independent support capabilities between segments, and for the first time since the start of ISS, the necessity to revise Life Support strategy agreements. Independent operating strategies coupled with the loss of the Space Shuttle supply and return capabilities in 2010 offer new and unique challenges. This paper will discuss the evolution of the ISS Life Support hardware strategy in support of 6-Crew on ISS, as well as the continued work that is necessary to ensure the support of crew and ISS Program objectives through the life of station.

Duchesne, Stephanie M.↗
NASA NTRS2009

Environmental Control and Life Support Integration Strategy for 6-Crew Operations

The International Space Station (ISS) crew compliment will be increasing in size from 3 to 6 crew members in the summer of 2009. In order to support this increase in crew on ISS, the United States on-orbit Segment (USOS) has been outfitted with a suite of regenerative Environmental Control and Life Support (ECLS) hardware including an Oxygen Generation System(OGS), Waste and Hygiene Compartment (WHC), and a Water Recovery System (WRS). The WRS includes the Urine Processor Assembly (UPA) and the Water Processor Assembly (WPA). A critical step in advancing to a 6Crew support capability on ISS is a full checkedout and verification of the Regenerative ECLS hardware. With a successful checkout, the ISS will achieve full redundancy in its onorbit life support system between the USOS and Russian Segment (RS). The additional redundancy created by the Regenerative ECLS hardware creates the opportunity for independent support capabilities between segments, and for the first time since the start of ISS, the necessity to revise Life Support strategy agreements. Independent operating strategies coupled with the loss of the Space Shuttle supply and return capabilities in 2010 offers additional challenges. These challenges create the need for a higher level of onorbit consumables reserve to ensure crewmember life support during a system failure. This paper will discuss the evolution of the ISS Life Support hardware strategy in support of 6Crew on ISS, as well as the continued work which will be necessary to ensure the support of crew and ISS Program objectives through the life of station.

FROM↗
NASA NTRS2004

Flywheel Single-Axis Integrated Momentum and Power Control System Demonstrated

On July 10, 2003, the NASA Glenn Research Center flywheel team experimentally demonstrated a two-flywheel-module system that simultaneously provided attitude control in a single axis and regulated power. The test was conducted using the D1 flywheel module and the high-speed shaft (HSS) in the High Energy Flywheel Facility (HEFF). Both of these flywheel modules consist of a magnetically levitated rotor with an integral motor/generator, a vacuum housing, and mechanical touchdown bearings. Energy is stored kinetically in the rotor. The motor/generator allows energy to be added to or withdrawn from the rotor, and magnetic bearings and a vacuum enclosure are used to minimize losses.

Soeder, James F.↗
NASA NTRS1990

Integrated aeroservoelastic synthesis for roll control

The objective of this study is to illustrate an integrated, parallel design procedure for optimal structural, aerodynamic, and aileron synthesis of an aircraft wing. The effects of combining weight minimization with structural tailoring (ply orientation and thickness) of a lifting surface, together with the wing geometry (sweep angle and taper ratio), and the aileron geometry (spanwise location and chordwise size) upon the lateral control effectiveness are discussed. Several optimization studies for the minimization of aileron hinge moment and wing weight, subject to a specified constant aircraft roll rate at a design airspeed (roll effectiveness), are performed.

Nam, Chang-Ho↗
DOE OSTI2023

A Vision for Coupling Operation of US Fusion Facilities with HPC Systems and the Implications for Workflows and Data Management

The operation of large US Department of Energy (DOE) research facilities, like the DIII-D National Fusion Facility, results in the collection of complex multi-dimensional scientific datasets, both experimental and model-generated. In the future, it is envisioned that integrated data analysis coupled with large-scale high performance computing (HPC) simulations will be used to improve experimental planning and operation. Practically, massive data sets from these simulations provide the physics basis for generation of both reduced semi-analytic and machine-learning-based models. Storage of both HPC simulation datasets (generated from US DOE leadership computing facilities) and experimental datasets presents significant challenges. In this paper, we present a vision for a DOE-wide data management workflow that integrates US DOE fusion facilities with leadership computing facilities. Data persistence and long-term availability beyond the length of allocated projects is essential, particularly for verification and recalibration of artificial intelligence and machine learning (AI/ML) models. Because these data sets are often generated and shared among hundreds of users across multiple leadership computing facility centers, they would benefit from cross-platform accessibility, persistent identifiers (e.g. DOI, or digital object identifier), and provenance tracking. Here, the ability to handle different data access patterns suggests that a combination of low cost, high latency (e.g. for storing ML training sets) and high cost, low latency systems (e.g. for real-time, integrated machine control feedback) may be needed.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Optimal Energy Dispatch Controller for Fuel Cell-Integrated Multi-Zone Building

Stationary fuel cells provide potential opportunities for energy savings when integrated with buildings. Through smart dispatch of both electrical power and heat generated by the fuel cells and managing the building loads, the buildings can achieve more efficient operation. In this paper, we develop an optimal energy dispatch controller to operate a fuel cell-integrated building. The controller leverages the inherent thermal storage and the dispatchable fuel cell to reduce its operating cost and to allow the building to participate in grid services. The proposed controller is implemented on two types of commercial buildings, a large office building and a large hotel, and the effectiveness of the controller is demonstrated through simulations. The results also indicate that the potential saving varies significantly with different system parameters, including season, fuel prices, and equipment sizing, which provide helpful insights for building operators and other stake holders.

39 EE - Hydrogen and Fuel Cell Technologies (EE-3F↗
DOE OSTI2023

Experimental Performance of a Nonlinear Control Strategy to Regulate Temperature of a High-Temperature Solar Reactor

Abstract Despite the significant potential of solar thermochemical process technology for storing solar energy as solid-state solar fuel, several challenges have made its industrial application difficult. It is important to note that solar energy has a transient nature that causes instability and reduces process efficiency. Therefore, it is crucial to implement a robust control system to regulate the process temperature and tackle the shortage of incoming solar energy during cloudy weather. In our previous works, different model-based control strategies were developed namely a proportional integral derivative controller (PID) with gain scheduling and adaptive model predictive control (MPC). These methods were tested numerically to regulate the temperature inside a high-temperature tubular solar reactor. In this work, the proposed control strategies were experimentally tested under various operation conditions. The controllers were challenged to track different setpoints (500 °C, 1000 °C, and 1450 °C) with different amounts of gas/particle flowrates. Additionally, the flow controller was tested to regulate the reactor temperature under a cloudy weather scenario. The ultimate goal was to produce 5 kg of reduced solar fuel magnesium manganese oxide (MgMn2O4) successfully, and the controllers were able to track the required process temperature and reject disturbances despite the system's strong nonlinearity. The experimental results showed a maximum error in the temperature setpoint of less than 0.5% (6 °C), and the MPC controller demonstrated superior performance in reducing the control effort and rejecting disturbances.

Energy & Fuels↗
NASA NTRS1981

The CELSS program - An overview of its structure and use of computer modelling

NASA has initiated a research program, CELSS, directed at the acquisition of the knowledge and technology required for the development of an autonomous, regenerative life support system. The program is structured to promote effective, cooperative research in fundamental, applied and engineering science. The initial research thrusts involve investigations into problems of food production, waste processing and system control and integration. In the area of food production both conventional, higher plant-based processes as well as chemosynthetic food production technologies are being investigated. Alternative waste processing procedures, both biological and physicochemical, are being examined. Computer based modelling as an aid to design and analysis is an integral part of the approach to system control and management. A mass balance model depicting the flow of elemental mass in a conceptualized closed, regenerative life support system is described.

Averner, M. M.↗
NASA NTRS1991

A robust momentum management and attitude control system for the space station

A game theoretic controller is synthesized for momentum management and attitude control of the Space Station in the presence of uncertainties in the moments of inertia. Full state information is assumed since attitude rates are assumed to be very assurately measured. By an input-output decomposition of the uncertainty in the system matrices, the parameter uncertainties in the dynamic system are represented as an unknown gain associated with an internal feedback loop (IFL). The input and output matrices associated with the IFL form directions through which the uncertain parameters affect system response. If the quadratic form of the IFL output augments the cost criterion, then enhanced parameter robustness is anticipated. By considering the input and the input disturbance from the IFL as two noncooperative players, a linear-quadratic differential game is constructed. The solution in the form of a linear controller is used for synthesis. Inclusion of the external disturbance torques results in a dynamic feedback controller which consists of conventional PID (proportional integral derivative) control and cyclic disturbance rejection filters. It is shown that the game theoretic design allows large variations in the inertias in directions of importance.

Speyer, J. L.↗
NASA NTRS1991

Research flight-control system development for the F-18 high alpha research vehicle

The F-18 high alpha research vehicle was recently modified by adding a thrust vectoring control system. A key element in the modification was the development of a research flight control system integrated with the basic F-18 flight control system. Discussed here are design requirements, system development, and research utility of the resulting configuration as an embedded system for flight research in the high angle of attack regime. Particular emphasis is given to control system modifications and control law features required for high angle of attack flight. Simulation results are used to illustrate some of the thrust vectoring control system capabilities and predicted maneuvering improvements.

Pahle, Joseph W.↗
NASA NTRS1992

Robust momentum management and attitude control system for the Space Station

A game theoretic controller is synthesized for momentum management and attitude control of the Space Station in the presence of uncertainties in the moments of inertia. Full state information is assumed since attitude rates are assumed to be very accurately measured. By an input-output decomposition of the uncertainty in the system matrices, the parameter uncertainties in the dynamic system are represented as an unknown gain associated with an internal feedback loop (IFL). The input and output matrices associated with the IFL form directions through which the uncertain parameters affect system response. If the quadratic form of the IFL output augments the cost criterion, then enhanced parameter robustness is anticipated. By considering the input and the input disturbance from the IFL as two noncooperative players, a linear-quadratic differential game is constructed. The solution in the form of a linear controller is used for synthesis. Inclusion of the external disturbance torques results in a dynamic feedback controller which consists of conventional PID (proportional integral derivative) control and cyclic disturbance rejection filters. It is shown that the game theoretic design allows large variations in the inertias in directions of importance.

Rhee, Ihnseok↗
NASA NTRS1994

Computer code for controller partitioning with IFPC application: A user's manual

A user's manual for the computer code for partitioning a centralized controller into decentralized subcontrollers with applicability to Integrated Flight/Propulsion Control (IFPC) is presented. Partitioning of a centralized controller into two subcontrollers is described and the algorithm on which the code is based is discussed. The algorithm uses parameter optimization of a cost function which is described. The major data structures and functions are described. Specific instructions are given. The user is led through an example of an IFCP application.

Schmidt, Phillip H.↗
NASA NTRS1994

A neural network controller for automated composite manufacturing

At McDonnell Douglas Aerospace (MDA), an artificial neural network based control system has been developed and implemented to control laser heating for the fiber placement composite manufacturing process. This neurocontroller learns an approximate inverse model of the process on-line to provide performance that improves with experience and exceeds that of conventional feedback control techniques. When untrained, the control system behaves as a proportional plus integral (PI) controller. However after learning from experience, the neural network feedforward control module provides control signals that greatly improve temperature tracking performance. Faster convergence to new temperature set points and reduced temperature deviation due to changing feed rate have been demonstrated on the machine. A Cerebellar Model Articulation Controller (CMAC) network is used for inverse modeling because of its rapid learning performance. This control system is implemented in an IBM compatible 386 PC with an A/D board interface to the machine.

Lichtenwalner, Peter F.↗
NASA NTRS1997

Research Related to Multi Degree of Freedom Magnetic Suspensions

This thesis covers the activities associated with (1) recommissioning of the 6-inch Magnetic Suspension and Balance System (MSBS) and (2) enhancing the Annular Suspension and Pointing System (ASPS). These activities continue the program of research in the multi degree of freedom magnetic suspension program at Old Dominion University. The 6-inch MSBS is a large gap magnetic suspension system used as a model support and balance system in wind tunnels. The first stage of recommissioning of the 6-inch MSBS for the 6-inch subsonic wind tunnel is performed. Experimental data and computational results for the magnetic field distribution of the MSBS are given and compared with the estimated magnetic field strength. The comparison indicates that the magnet system is still operating as designed. The Electromagnetic Position Sensor used in the 6-inch MSBS is analyzed before its find reinstatement. The ASPS is a small gap magnetic suspension system providing orientation, mechanical isolation and fine pointing of space payloads. The control system of the ASPS is improved by designing a new code to realize red time control over the system. The original Proportional-Derivative controller is upgraded to a Proportional-Integral-Derivative controller. This progress leads to a system which is more stable and robust with less noise. This new controller is generic and can be adapted to the 6-inch MSBS. Finally, future work on these two systems is proposed.

Britcher, Colin↗
NASA NTRS1998

High-Alpha Research Vehicle Lateral-Directional Control Law Description, Analyses, and Simulation Results

This report contains a description of a lateral-directional control law designed for the NASA High-Alpha Research Vehicle (HARV). The HARV is a F/A-18 aircraft modified to include a research flight computer, spin chute, and thrust-vectoring in the pitch and yaw axes. Two separate design tools, CRAFT and Pseudo Controls, were integrated to synthesize the lateral-directional control law. This report contains a description of the lateral-directional control law, analyses, and nonlinear simulation (batch and piloted) results. Linear analysis results include closed-loop eigenvalues, stability margins, robustness to changes in various plant parameters, and servo-elastic frequency responses. Step time responses from nonlinear batch simulation are presented and compared to design guidelines. Piloted simulation task scenarios, task guidelines, and pilot subjective ratings for the various maneuvers are discussed. Linear analysis shows that the control law meets the stability margin guidelines and is robust to stability and control parameter changes. Nonlinear batch simulation analysis shows the control law exhibits good performance and meets most of the design guidelines over the entire range of angle-of-attack. This control law (designated NASA-1A) was flight tested during the Summer of 1994 at NASA Dryden Flight Research Center.

Davidson, John B.↗