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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Digital phase-locked-loop speed sensor for accuracy improvement in analog speed controls

A digital speed control that can be combined with a proportional analog controller is described. The stability and transient response of the analog controller were retained and combined with the long-term accuracy of a crystal-controlled integral controller. A relatively simple circuit was developed by using phase-locked-loop techniques and total error storage. The integral digital controller will maintain speed control accuracy equal to that of the crystal reference oscillator.

Birchenough, A. G.↗
NASA NTRSDate not supplied

Liquid Nitrogen Testing of an Integrated Reaction Control System

Integrated Reaction Control Systems (IRCS) are considered an enabling technology for future human exploration of the solar system. An IRCS uses the same fuel and oxidizer as the main propulsion system, allowing for increased performance and simplified cryogenic fluid management operations. The IRCS team at Marshall Spaceflight Center is currently evaluating an IRCS system that uses a combination of electric pumps and pressure-regulation devices to provide a constant flow of conditioned propellant to a thruster bank during operation. In contrast to accumulator and gasifier designs, the recirculation loop design is less massive and can provide large, sustained flowrates to the thruster inlet. In the summer 2021 test series presented herein, the feasibility of this concept was evaluated using liquid nitrogen as a simulant for liquid oxygen. The goals of this test series were to demonstrate the ability of the pump and pressure regulator to maintain adequate thruster inlet conditions during transient operation, and to demonstrate the ability for the system to operate in an “idle mode” that maintains system chill between activations. During test operations, the back-pressure regulator responded more slowly than the opening/closing of valves in the thruster simulant, but it was still able to attenuate the pressure fluctuation at the pump discharge and ensure a stable flowrate through the pump. Similarly, the pump was able to be run far below its nominal operating point and successfully flow sufficient fluid to maintain chill conditions.

integrated RCS↗
NASA NTRSDate not supplied

Liquid Nitrogen Testing of an Integrated Reaction Control System

Integrated Reaction Control Systems (IRCS) are considered an enabling technology for future human exploration of the solar system. An IRCS uses the same fuel and oxidizer as the main propulsion system, allowing for increased performance and simplified cryogenic fluid management operations. The IRCS team at Marshall Spaceflight Center is currently evaluating an IRCS system that uses a combination of electric pumps and pressure-regulation devices to provide a constant flow of conditioned propellant to a thruster bank during operation. In contrast to accumulator and gasifier designs, the recirculation loop design is less massive and can provide large, sustained flowrates to the thruster inlet. In the summer 2021 test series presented herein, the feasibility of this concept was evaluated using liquid nitrogen as a simulant for liquid oxygen. The goals of this test series were to demonstrate the ability of the pump and pressure regulator to maintain adequate thruster inlet conditions during transient operation, and to demonstrate the ability for the system to operate in an “idle mode” that maintains system chill between activations. During test operations, the back-pressure regulator responded more slowly than the opening/closing of valves in the thruster simulant, but it was still able to attenuate the pressure fluctuation at the pump discharge and ensure a stable flowrate through the pump. Similarly, the pump was able to be run far below its nominal operating point and successfully flow sufficient fluid to maintain chill conditions.

integrated RCS↗
NASA NTRS2022

Liquid Nitrogen Testing of an Integrated Reaction Control System

Integrated Reaction Control Systems (IRCS) are considered an enabling technology for future human exploration of the solar system. An IRCS uses the same fuel and oxidizer as the main propulsion system, allowing for increased performance and simplified cryogenic fluid management operations. The IRCS team at Marshall Spaceflight Center is currently evaluating an IRCS system that uses a combination of electric pumps and pressure-regulation devices to provide a constant flow of conditioned propellant to a thruster bank during operation. In contrast to accumulator and gasifier designs, the recirculation loop design is less massive and can provide large, sustained flowrates to the thruster inlet. In the summer 2021 test series presented herein, the feasibility of this concept was evaluated using liquid nitrogen as a simulant for liquid oxygen. The goals of this test series were to demonstrate the ability of the pump and pressure regulator to maintain adequate thruster inlet conditions during transient operation, and to demonstrate the ability for the system to operate in an “idle mode” that maintains system chill between activations. During test operations, the back-pressure regulator responded more slowly than the opening/closing of valves in the thruster simulant, but it was still able to attenuate the pressure fluctuation at the pump discharge and ensure a stable flowrate through the pump. Similarly, the pump was able to be run far below its nominal operating point and successfully flow sufficient fluid to maintain chill conditions.

RCS↗
NASA NTRSDate not supplied

Liquid Nitrogen Testing of An Integrated Reaction Control System

Integrated Reaction Control Systems (IRCS) are considered an enabling technology for future human exploration of the solar system. An IRCS uses the same fuel and oxidizer as the main propulsion system, allowing for increased performance and simplified cryogenic fluid management operations. The IRCS team at Marshall Spaceflight Center is currently evaluating an IRCS system that uses a combination of electric pumps and pressure-regulation devices to provide a constant flow of conditioned propellant to a thruster bank during operation. In contrast to accumulator and gasifier designs, the recirculation loop design is less massive and can provide large, sustained flowrates to the thruster inlet. In the summer 2021 test series presented herein, the feasibility of this concept was evaluated using liquid nitrogen as a simulant for liquid oxygen. The goals of this test series were to demonstrate the ability of the pump and pressure regulator to maintain adequate thruster inlet conditions during transient operation, and to demonstrate the ability for the system to operate in an “idle mode” that maintains system chill between activations. During test operations, the back-pressure regulator responded more slowly than the opening/closing of valves in the thruster simulant, but it was still able to attenuate the pressure fluctuation at the pump discharge and ensure a stable flowrate through the pump. Similarly, the pump was able to be run far below its nominal operating point and successfully flow sufficient fluid to maintain chill conditions.

RCS↗
NASA NTRSDate not supplied

Proof of Concept Testing for Integrated Reaction Control System

Integrated Reaction Control Systems (IRCS) are considered an enabling technology for future human exploration of the solar system. An IRCS uses the same fuel and oxidizer as the main propulsion system, allowing for increased performance and simplified cryogenic fluid management operations. The IRCS team at Marshall Spaceflight Center is currently evaluating an IRCS system that uses a combination of electric pumps and pressure-regulation devices to provide a constant flow of conditioned propellant to a thruster bank during operation. In the spring 2021 test series presented here, the feasibility of this concept was evaluated using liquid nitrogen as a simulant for liquid oxygen. The goal of this test series was to demonstrate the ability of the pump and pressure regulator to maintain adequate thruster inlet conditions during transient operation.

Cameron Hines↗
NASA NTRS1990

Propulsion system-flight control integration-flight evaluation and technology transition

Integration of propulsion and flight control systems and their optimization offering significant performance improvement are assessed. In particular, research programs conducted by NASA on flight control systems and propulsion system-flight control interactions on the YF-12 and F-15 aircraft are addressed; these programs have demonstrated increased thrust, reduced fuel consumption, increased engine life, and improved aircraft performance. Focus is placed on altitude control, speed-Mach control, integrated controller design, as well as flight control systems and digital electronic engine control. A highly integrated digital electronic control program is analyzed and compared with a performance seeking control program. It is shown that the flight evaluation and demonstration of these technologies have been a key part in the transition of the concepts to production and operational use on a timely basis.

Burcham, Frank W., Jr.↗
NASA NTRS1996

Integrated Aeropropulsion Control System Design

%T Integrated Aeropropulsion Control System Design%A C-F. Lin%A Francis X. Hurley%A Jie Huang%A F. Y. Hadaegh%J International Conference on Control and Information(psi)995%C Hong Kong%D June 1995%K aeropropulsion, control, system%U http://jpltrs.jpl.nasa.gov/1995/95-0658.pdfAn integrated intelligent control approach is proposed to design a high performance control system for aeropropulsion systems based on advanced sensor processing, nonlinear control and neural fuzzy control integration. Our approach features the following innovations:??e complexity and uncertainty issues are addressed via the distributed parallel processing, learning, and online reoptimization properties of neural networks.??e nonlinear dynamics and the severe coupling can be naturally incorporated into the design framework.??e knowledge base and decision making logic furnished by fuzzy systems leads to a human intelligence enhanced control scheme.In addition, fault tolerance, health monitoring and reconfigurable control strategies will be accommodated by this approach to ensure stability, graceful degradation and reoptimization in the case of failures, malfunctions and damage.!.

aeropropulsion control systems↗
NASA NTRS1992

Flight-determined benefits of integrated flight-propulsion control systems

The fundamentals of control integration for propulsion are reviewed giving practical illustrations of its use to demonstrate the advantages of integration. Attention is given to the first integration propulsion-control systems (IPCSs) which was developed for the F-111E, and the integrated controller design is described that NASA developed for the YF-12C aircraft. The integrated control systems incorporate a range of aircraft components including the engine, inlet controls, autopilot, autothrottle, airdata, navigation, and/or stability-augmentation systems. Also described are emergency-control systems, onboard engine optimization, and thrust-vectoring control technologies developed for the F-18A and the F-15. Integrated flight-propulsion control systems are shown to enhance the thrust, range, and survivability of the aircraft while reducing fuel consumption and maintenance.

Stewart, James F.↗
NASA NTRS1993

Sensitivity analysis of Lyapunov and Riccati equations with application to controls-structures integrated design

Controls-structure integrated design is a complicated multidisciplinary design optimization problem which involves the state equations pertaining to open-loop eigenvalues and control laws. In order to alleviate the intensity of the computation, this study uses the adjoint variable method to derive sensitivity equations for the eigenvalue, Liapunov, and Riccati equations. These individual sensitivity equations are then combined together to form the multidisciplinary sensitivity equations for the control structure integrated design problems. A set of linear sensitivity equations, proportional in number to the number of performance functions involved in the optimization process, are solved. This proposed approach may provide a great saving in computer resources. The validity of the newly developed sensitivity equations is verified by numerical examples.

Hou, Gene↗
NASA NTRS1993

Application of controller partitioning optimization procedure to integrated flight/propulsion control design for a STOVL aircraft

A parameter optimization framework has earlier been developed to solve the problem of partitioning a centralized controller into a decentralized, hierarchical structure suitable for integrated flight/propulsion control implementation. This paper presents results from the application of the controller partitioning optimization procedure to IFPC design for a Short Take-Off and Vertical Landing (STOVL) aircraft in transition flight. The controller partitioning problem and the parameter optimization algorithm are briefly described. Insight is provided into choosing various 'user' selected parameters in the optimization cost function such that the resulting optimized subcontrollers will meet the characteristics of the centralized controller that are crucial to achieving the desired closed-loop performance and robustness, while maintaining the desired subcontroller structure constraints that are crucial for IFPC implementation. The optimization procedure is shown to improve upon the initial partitioned subcontrollers and lead to performance comparable to that achieved with the centralized controller. This application also provides insight into the issues that should be addressed at the centralized control design level in order to obtain implementable partitioned subcontrollers.

Garg, Sanjay↗
NASA NTRS1993

Application of controller partitioning optimization procedure to integrated flight/propulsion control design for a STOVL aircraft

A parameter optimization framework has earlier been developed to solve the problem of partitioning a centralized controller into a decentralized, hierarchical structure suitable for integrated flight/propulsion control implementation. This paper presents results from the application of the controller partitioning optimization procedure to IFPC design for a Short Take-Off and Vertical Landing (STOVL) aircraft in transition flight. The controller partitioning problem and the parameter optimization algorithm are briefly described. Insight is provided into choosing various 'user' selected parameters in the optimization cost function such that the resulting optimized subcontrollers will meet the characteristics of the centralized controller that are crucial to achieving the desired closed-loop performance and robustness, while maintaining the desired subcontroller structure constraints that are crucial for IFPC implementation. The optimization procedure is shown to improve upon the initial partitioned subcontrollers and lead to performance comparable to that achieved with the centralized controller. This application also provides insight into the issues that should be addressed at the centralized control design level in order to obtain implementable partitioned subcontrollers.

Garg, Sanjay↗
NASA NTRS1991

Design and piloted simulation evaluation of integrated flight/propulsion controls for STOVL aircraft

Integrated flight/propulsion control systems have been designed for operation of STOVL aircraft over the low speed powered-lift flight envelope. The control system employs command modes for attitude, flightpath angle and flightpath acceleration during transition, and translational velocity command for hover and vertical landing. The command modes and feedback control are implemented in the form of a state-rate feedback implicit model follower to achieve the desired flying qualities and to suppress the effects of external disturbances and variations in the aircraft characteristics over the low speed envelope. A nonlinear inverse system was used to translate the output from these commands and feedback control into commands for the various aerodynamic and propulsion control effectors that are employed in powered-lift flight. Piloted evaluations of these STOVL integrated control designs have been conducted on Ames Research Center's Vertical Motion Simulator to assess flying qualities over the low-speed flight envelope. Results indicate that Level 1 flying qualities are achieved with this control system concept for each of these low-speed operations over a wide range of wind, atmospheric turbulence, and visibility conditions.

Franklin, James A.↗
NASA NTRS1991

Optimizing aircraft performance with adaptive, integrated flight/propulsion control

The Performance-Seeking Control (PSC) integrated flight/propulsion adaptive control algorithm presented was developed in order to optimize total aircraft performance during steady-state engine operation. The PSC multimode algorithm minimizes fuel consumption at cruise conditions, while maximizing excess thrust during aircraft accelerations, climbs, and dashes, and simultaneously extending engine service life through reduction of fan-driving turbine inlet temperature upon engagement of the extended-life mode. The engine models incorporated by the PSC are continually upgraded, using a Kalman filter to detect anomalous operations. The PSC algorithm will be flight-demonstrated by an F-15 at NASA-Dryden.

Smith, R. H.↗
NASA NTRS1989

Multiplexing electro-optic architectures for advanced aircraft integrated flight control systems

This report describes the results of a 10 month program sponsored by NASA. The objective of this program was to evaluate various optical sensor modulation technologies and to design an optimal Electro-Optic Architecture (EOA) for servicing remote clusters of sensors and actuators in advanced aircraft flight control systems. The EOA's supply optical power to remote sensors and actuators, process the modulated optical signals returned from the sensors, and produce conditioned electrical signals acceptable for use by a digital flight control computer or Vehicle Management System (VMS) computer. This study was part of a multi-year initiative under the Fiber Optic Control System Integration (FOCSI) program to design, develop, and test a totally integrated fiber optic flight/propulsion control system for application to advanced aircraft. Unlike earlier FOCSI studies, this program concentrated on the design of the EOA interface rather than the optical transducer technology itself.

Seal, D. W.↗