Components and systems design for a 400 kw Rankine cycle space power system.
Alkali metal Rankine cycle space power system component and systems design
SPACECRAFT COMPONENT↗
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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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System identification requirements for high-bandwidth rotorcraft flight control system design
The application of system identification methods to high-bandwidth rotorcraft flight control system design is examined. Flight test and modeling requirements are illustrated using flight test data from a BO-105 hingeless rotor helicopter. The proposed approach involves the identification of nonparametric frequency-response models followed by parametric (transfer funtion and state space) model identification. Results for the BO-105 show the need for including coupled body/rotor flapping and lead-lag dynamics in the identification model structure to allow the accurate prediction of control system bandwidth limitations. Lower-order models are useful for estimating nominal control system performance only when the flight data used for the identification are band-limited to be consistent with the frequency range of applicability of the model. The flight test results presented in this paper are consistent with theoretical studies by previous researchers.
Tischler, Mark B.↗
Dissipative rendering and neural network control system design
Model-based control system designs are limited by the accuracy of the models of the plant, plant uncertainty, and exogenous signals. Although better models can be obtained with system identification, the models and control designs still have limitations. One approach to reduce the dependency on particular models is to design a set of compensators that will guarantee robust stability to a set of plants. Optimization over the compensator parameters can then be used to get the desired performance. Conservativeness of this approach can be reduced by integrating fundamental properties of the plant models. This is the approach of dissipative control design. Dissipative control designs are based on several variations of the Passivity Theorem, which have been proven for nonlinear/linear and continuous-time/discrete-time systems. These theorems depend not on a specific model of a plant, but on its general dissipative properties. Dissipative control design has found wide applicability in flexible space structures and robotic systems that can be configured to be dissipative. Currently, there is ongoing research to improve the performance of dissipative control designs. For aircraft systems that are not dissipative active control may be used to make them dissipative and then a dissipative control design technique can be used. It is also possible that rendering a system dissipative and dissipative control design may be combined into one step. Furthermore, the transformation of a non-dissipative system to dissipative can be done robustly. One sequential design procedure for finite dimensional linear time-invariant systems has been developed. For nonlinear plants that cannot be controlled adequately with a single linear controller, model-based techniques have additional problems. Nonlinear system identification is still a research topic. Lacking analytical models for model-based design, artificial neural network algorithms have recently received considerable attention. Using their universal approximation property, neural networks have been introduced into nonlinear control designs in several ways. Unfortunately, little work has appeared that analyzes neural network control systems and establishes margins for stability and performance. One approach for this analysis is to set up neural network control systems in the framework presented above. For example, one neural network could be used to render a system to be dissipative, a second strictly dissipative neural network controller could be used to guarantee robust stability.
Gonzalez, Oscar R.↗
Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 1: Baseline system description
A system baseline design oriented to the requirements of the next generation of Earth Observatory Satellite missions is presented. The first mission (EOS-A) is envisioned as a two-fold mission which (1) provides a continuum of data of the type being supplied by ERTS for the emerging operational applications and also (2) expands the research and development activities for future instrumentation and analysis techniques. The baseline system specifically satisfies the requirements of this first mission. However, EOS-A is expected to be the first of a series of earth observation missions. Thus the baseline design has been developed so as to accommodate these latter missions effectively as the transition is made from conventional, expendable launch vehicles and spacecraft to the Shuttle Space Transportation System era. Further, a subset of alternative missions requirements including Seasat, SEOS, SMM and MSS-5 have been analyzed to verify that the spacecraft design to serve a multi-mission role is economically sound. A key feature of the baseline system design is the concept of a modular observatory system whose elements are compatible with varying levels of launch vehicle capability. The design configuration can be used with either the Delta or Titan launch vehicles and will adapt readily to the space shuttle when that system becomes available in the early 1980's.
Source record↗
Multicriteria Gain Tuning for Rotorcraft Flight Controls (also entitled The Development of the Conduit Advanced Control System Design and Evaluation Interface with a Case Study Application Fly by Wire Helicopter Design)
Handling qualities analysis and control law design would seem to be naturally complimenting components of aircraft flight control system design, however these two closely coupled disciplines are often not well integrated in practice. Handling qualities engineers and control system engineers may work in separate groups within an aircraft company. Flight control system engineers and handling quality specialists may come from different backgrounds and schooling and are often not aware of the other group's research. Thus while the handling qualities specifications represent desired aircraft response characteristics, these are rarely incorporated directly in the control system design process. Instead modem control system design techniques are based on servo-loop robustness specifications, and simple representations of the desired control response. Comprehensive handling qualities analysis is often left until the end of the design cycle and performed as a check of the completed design for satisfactory performance. This can lead to costly redesign or less than satisfactory aircraft handling qualities when the flight testing phase is reached. The desire to integrate the fields of handling qualities and flight,control systems led to the development of the CONDUIT system. This tool facilitates control system designs that achieve desired handling quality requirements and servo-loop specifications in a single design process. With CONDUIT, the control system engineer is now able to directly design and control systems to meet the complete handling specifications. CONDUIT allows the designer to retain a preferred control law structure, but then tunes the system parameters to meet the handling quality requirements.
Biezad, Daniel↗
NIMBUS COMPUTER SYSTEM DESIGN
Nimbus satellite - computer system design and programming
NIMBUS SATELLITE↗
Titan/Mars hard lander. Volume 2 - Autonomous capsule system design study
Autonomous capsule system design study for Titan/ Mars hard lander
Source record↗
Coding, testing and documentation of processors for the flight design system
The general functional design and implementation of processors for a space flight design system are briefly described. Discussions of a basetime initialization processor; conic, analytical, and precision coasting flight processors; and an orbit lifetime processor are included. The functions of several utility routines are also discussed.
Source record↗
System identification requirements for high-bandwidth rotorcraft flight control system design
The application of system identification methods to high-bandwidth rotorcraft flight control system design is examined. Flight test and modeling requirements are illustrated using flight test data from a BO-105 hingeless rotor helicopter. The proposed approach involves the identification of nonparametric (transfer function and state space) model identification. Results for the BO-105 show the need for including coupled body/rotor flapping and lead-lag dynamics in the identification model structure to allow the accurate prediction of control ssytem bandwidth limitations.
Tischler, Mark B.↗
A Robotics Systems Design Need: A Design Standard to Provide the Systems Focus that is Required for Longterm Exploration Efforts
The United States is entering a new period of human exploration of the inner Solar System, and robotic human helpers will be partners in that effort. In order to support integration of these new worker robots into existing and new human systems, a new design standard should be developed, to be called the Robot-Systems Integration Standard (RSIS). It will address the requirements for and constraints upon robotic collaborators with humans. These workers are subject to the same functional constraints as humans of work, reach, and visibility/situational awareness envelopes, and they will deal with the same maintenance and communication interfaces. Thus, the RSIS will be created by discipline experts with the same sort of perspective on these and other interface concerns as human engineers.
Dischinger, H. Charles., Jr.↗
Astrionics system designers handbook, volume 1
Hardware elements in new and advanced astrionics system designs are discussed. This cost effective approach has as its goal the reduction of R&D and testing costs through the application of proven and tested astrionics components. The ready availability to the designer of data facts for applicable system components is highly desirable. The astrionics System Designers Handbook has as its objective this documenting of data facts to serve the anticipated requirements of the astrionics system designer. Eleven NASA programs were selected as the reference base for the document. These programs are: ATS-F, ERTS-B, HEAO-A, OSO-I, Viking Orbiter, OAO-C, Skylab AM/MDA, Skylab ATM, Apollo 17 CSM, Apollo 17 LM and Mariner Mars 71. Four subsystems were chosen for documentation: communications, data management, electrical power and guidance, navigation and control.
Source record↗
Ion extractor system design.
Ion extractor system for electrostatic thrustors designed, using salient features of digital computer and electrolytic tank analog methods
COMPUTER METHOD↗
Telemetry system design for Saturn vehicles.
Data system requirements for large space vehicles and flexible telemetry system design for all stages of Saturn IB and V vehicles
SATURN IB LAUNCH VEHICLE↗
System design of a Mars probe/lander.
System design of Voyager-class Mars Probe/ Lander, considering selections of entry aeroshell, landed capsule and descent and postimpact instrumentation
SYSTEMS DESIGN↗
System Design Techniques for Reducing the Power Requirements of Advanced life Support Systems
The high power requirement associated with overall operation of regenerative life support systems is a critical Z:p technological challenge. Optimization of individual processors alone will not be sufficient to produce an optimized system. System studies must be used in order to improve the overall efficiency of life support systems. Current research efforts at NASA Ames Research Center are aimed at developing approaches for reducing system power and energy usage in advanced life support systems. System energy integration and energy reuse techniques are being applied to advanced life support, in addition to advanced control methods for efficient distribution of power and thermal resources. An overview of current results of this work will be presented. The development of integrated system designs that reuse waste heat from sources such as crop lighting and solid waste processing systems will reduce overall power and cooling requirements. Using an energy integration technique known as Pinch analysis, system heat exchange designs are being developed that match hot and cold streams according to specific design principles. For various designs, the potential savings for power, heating and cooling are being identified and quantified. The use of state-of-the-art control methods for distribution of resources, such as system cooling water or electrical power, will also reduce overall power and cooling requirements. Control algorithms are being developed which dynamically adjust the use of system resources by the various subsystems and components in order to achieve an overall goal, such as smoothing of power usage and/or heat rejection profiles, while maintaining adequate reserves of food, water, oxygen, and other consumables, and preventing excessive build-up of waste materials. Reductions in the peak loading of the power and thermal systems will lead to lower overall requirements. Computer simulation models are being used to test various control system designs.
Finn, Cory↗
Low-Activity Waste Melter Process (LMP) System Design Description (Rev. 4)
This system design description (SDD) defines the technical, functional, and performance requirements of the low-activity waste (LAW) melter process system (LMP). This document details the waste treatment requirements, environmental compliance requirements, and authorization basis requirements of the LMP system as they are currently known and understood. This SDD describes the process and functional design requirements of the LMP, including the following: 1) Services and utility requirements, operating materials and supplies, and other external interfaces; 2) Operations limits and design bases; 3) Other criteria and requirements pertinent to the design of the LMP system; 4) Boundaries, system interfaces, and functional description of the LMP system. The LMP system is composed of two LAW melters of the same design with the contingency to add the third. Also included in the LMP system are the pour spouts, which are positioned under the melter discharge chambers of each melter, and the container level detectors. The boundaries, system interfaces, and functional description of the LMP system are provided in Section 2.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Galileo System Design for Orbital Operations
In April 1991, Galileo's X-band high gain antenna failed to deploy. An alternate approach which utilizes the spacecraft's S-band low gain antenna was conceived and is in development. This approach will enable the accomplishment of at least 70 percent of Galileo's original scientific objectives. The short development period dictates that the spacecraft system design, the ground data system design, and the operational system scenarios and procedures necessary to conduct the mission be developed concurrently, and places a premium on validating the system designs as early as possible. This paper presents an overview of the Galileo Mission, briefly describes the changes required to implement the orbital phase of the Galileo Mission, and describes the functional model of the end to end system which was developed to support the systems design effort.
Galileo↗
Human Factors Considerations in System Design
Human factors considerations in systems design was examined. Human factors in automated command and control, in the efficiency of the human computer interface and system effectiveness are outlined. The following topics are discussed: human factors aspects of control room design; design of interactive systems; human computer dialogue, interaction tasks and techniques; guidelines on ergonomic aspects of control rooms and highly automated environments; system engineering for control by humans; conceptual models of information processing; information display and interaction in real time environments.
Christine M Mitchell↗