Showing papers on "Conceptual design published in 1972"

Theory and Flight Verification of the TIFS Model-Following System

Abstract: The content of this paper describes the theoretical development and flight-test results of the model-following control system of the Air Force Total In-Flight Simulator (TIFS). A discussion of the conceptual design and detailed development of the system configuration is given. The manner in which the feedforward, gust compensator and lateral-directional feedback gains are obtained is developed. The feedforward and gust compensator gains are obtained by simple matrix algebra calculations. A sensitivity minimization approach using modern control theory is used to obtain the lateral-directional feedback gains. Digital simulation results are included to show the improvement in model-followi ng achieved with the feedback gains determined by this approach. Time histories of the model and TIFS responses from flight test are also included to show the quality of modelfollowing obtained with the system for both the lateral-directional and longitudinal modes of operation. These results verify the theory and design procedure used to obtain the TIFS model-following control system.

Conceptual design and analysis of an infared horizon sensor with compensation for atmospheric variability

Abstract: A horizon detection logic, based on a ratio-of-integrated-radiance concept, which detects the earth's horizon at a relatively stable height under all geographic and meteorological conditions was evaluated by computer simulation on a body of synthesized radiance profiles. An error-sensitivity analysis of the concept was performed, and optimum design parameter values for a sensor were determined. A conceptual design for an improved 15 micron sensor based on this analysis is discussed.

Conceptual design of an eight megabyte high performance charge-coupled storage device

Abstract: The design approach suggested to satisfy the conceptual requirements was the use of self-contained, charge-coupled storage chips with on-chip decoding. In this approach, the information on the memory chip is stored in a group of closed-loop shift registers, and random access is provided to any one of the registers by an on-chip dynamic FET decoder. In this way, n-control lines can select one of 2n shift registers.

Development of Lightweight Material Composites to Insulate Cryogenic Tanks for 30-Day Storage in Outer Space

Abstract: A conceptual design was developed for an MLI system which will meet the design constraints of an ILRV used for 7- to 30-day missions. The ten tasks are briefly described: (1) material survey and procurement, material property tests, and selection of composites to be considered; (2) definition of environmental parameters and tooling requirements, and thermal and structural design verification test definition; (3) definition of tanks and associated hardware to be used, and definition of MLI concepts to be considered; (4) thermal analyses, including purge, evacuation, and reentry repressurization analyses; (5) structural analyses (6) thermal degradation tests of composite and structural tests of fastener; (7) selection of MLI materials and system; (8) definition of a conceptual MLI system design; (9) evaluation of nondestructive inspection techniques and definition of procedures for repair of damaged areas; and (10) preparation of preliminary specifications.

The Economics of High-Rise Apartment Buildings of Alternate Design Configuration

Abstract: This is a study of the economic problems of conceptual design of high-rise apartment buildings. Definitions and techniques useful in total cost analysis are developed. The economic of building of alternate height, flood size, shape, and room size are explored quantitatively. Implications of these quantitative results are considered relative to zoning and to apartment design.

Reliability and Maintainability Analysis: A Conceptual Design Model

Abstract: : This study combines aspects of utility theory, probability theory, and mathematical programming to develop an efficient method for performing reliability/maintainability analysis during the early conceptual stages of system development. The general concepts of operational capability and system life cycle cost are used to construct an operational model for determining subsystem reliability and maintainability 'design point' characteristics. Consideration of both technological and cost uncertainty is incorporated within the model. Specifically, the method developed provides a systematic and operationally efficient technique for selecting subsystem reliability/ maintainability alternatives when (1) attainable subsystem reliability/ maintainability levels are not known with certainty, (2) all life cycle element cost flows are not known with certainty, (3) chance-constraint restrictions exist on some or all of the following factors: system availability, weight, reliabilty, maintainability, and/or R and D cost, (4) some subsystem reliability/maintainability design alternatives are interdependent (contingent and/or mutually-exclusive), (5) the suitability of selecting any particular system (combination of subsystem reliability/maintainability alternatives) depends upon both cost and risk considerations.

Principles of Performance Monitoring with Application to Automatic Landing

Abstract: A new development in the field of control systems is the Performance Monitor, a subsystem which is intended to assess the total (internal) and external state of a controlled dynamic system, and the expected effect of this state upon the safety of the system's operation. Although the concept appears to be of wide applicability, the only application studied by the authors is to aircraft automatic landing systems. In this application, performance monitoring will provide levels of safety and economy of utilization beyond the level possible by the traditional means of redundancy and internal monitoring alone. This paper presents a brief survey of the principles of autoland performance monitoring—from basic mathematics through conceptual design and testing. Hypothetical numerical examples are provided to clarify the concepts presented. HE early stages of autoland development saw extensive use of the conventional approach to guaranteeing safety and utility of the control system—reduction of system failures by use of reliable components, redundancy, and "internal" monitoring of subsystems (in-line and comparison monitoring). Although failure prevention and detection are important in themselves, this approach alone has not proved entirely satisfactory as an economical means for reduction of risk; e.g., redundancy has brought its own problems, such as equalization and nuisance disconnects. Even though effective in preventing and detecting failures, the conventional techniques provide no help for the many possible situations (e.g., ILS beam bends and noise, wind shears) which can lead to loss of an aircraft and its passengers without internal failure. Over the present and future commercial operational spectrum (categories II and III), these difficult situations will in fact occur with non-negligible frequency. Furthermore, in many of these situations the pilot (the only external monitor in the loop) will be lacking in high-fidelity out-the-window information, and simultaneously saturated with low-fidelity information, requiring much scanning, interpreting and crosschecking of instruments. The situation becomes increasingly difficult as touchdown approaches, since the time-to-go approaches, and finally becomes less than, the total of decision and response time. A Performance Monitor (PM) is a device which makes an assessment of the total (internal and external) state of the aircraft and the landing maneuver, and provides an effective man/machine interface to display this assessment to the pilot. The performance monitor assists the pilot in making go/no-go decisions under pressure and in the face of uncertainty. The goal in a performance monitor design is to substantially reduce landing risk without imposing an unacceptable economic penalty in the number of aborted approaches.

Design concepts for an on-board coherent optical image processor

Abstract: On-board spacecraft image data processing systems for transmitting processed data rather than raw data are discussed. A brief history of the development of the optical data processing techniques is presented along with the conceptual design of a coherent optical system with a noncoherent image input.

Design considerations for fiber composite structures

Abstract: An overview of the design methodology for designing structural components from fiber composites is presented. In particular, the need for new conceptual structural designs for the future is discussed and the evolution of conceptual design is illustrated. Sources of design data, analysis and design procedures, and the basic components of structural fiber composites are cited and described. Examples of tradeoff studies and optimum designs are discussed and a simple structure is described in some detail.