Wind-tunnel tests of a series of parachutes designed for controllable gliding flight
Wind tunnel tests of recovery parachutes designed for controllable gliding flight
RECOVERY PARACHUTE↗
SEARCH · Engineering Papers
Results for “Control design”
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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Parameter plane techniques applied to tactical missile control system design
Stability analysis parameter plane technique for tactical missile control system design, correlating variable parameters with characteristic equation roots location
Seltzer, S. M.↗
IMPAC: An Integrated Methodology for Propulsion and Airframe Control
The National Aeronautics and Space Administration is actively involved in the development of enabling technologies that will lead towards aircraft with new/enhanced maneuver capabilities such as Short Take-Off Vertical Landing (STOVL) and high angle of attack performance. Because of the high degree of dynamic coupling between the airframe and propulsion systems of these types of aircraft, one key technology is the integration of the flight and propulsion control. The NASA Lewis Research Center approach to developing Integrated Flight Propulsion Control (IFPC) technologies is an in-house research program referred to as IMPAC (Integrated Methodology for Propulsion and Airframe Control). The goals of IMPAC are to develop a viable alternative to the existing integrated control design methodologies that will allow for improved system performance and simplicity of control law synthesis and implementation, and to demonstrate the applicability of the methodology to a supersonic STOVL fighter aircraft. Based on some preliminary control design studies that included evaluation of the existing methodologies, the IFPC design methodology that is emerging at the Lewis Research Center consists of considering the airframe and propulsion system as one integrated system for an initial centralized controller design and then partitioning the centralized controller into separate airframe and propulsion system subcontrollers to ease implementation and to set meaningful design requirements for detailed subsystem control design and evaluation. An overview of IMPAC is provided and detailed discussion of the various important design and evaluation steps in the methodology are included.
Garg, Sanjay↗
High-capacity reaction-wheel attitude control.
Design criteria for high capacity reaction wheel system for attitude control, derived from analytic development, digital computer simulation and experimental model
COMPUTER SIMULATION↗
Hubble Space Telescope Reduced-Gyro Control Law Design, Implementation, and On-Orbit Performance
Following gyro failures in April 2001 and April 2003, HST Pointing Control System engineers designed reduced-gyro control laws to extend the spacecraft science mission. The Two-Gyro Science (TGS) and One-Gyro Science (OGS) control laws were designed and implemented using magnetometers, star trackers, and Fine Guidance Sensors in succession to control vehicle rate about the missing gyro axes. Both TGS and OGS have demonstrated on-orbit pointing stability of 7 milli-arcseconds or less, which depends upon the guide star magnitude used by the Fine Guidance Sensor. This paper describes the design, implementation, and on-orbit performance of the TGS and OGS control law fine-pointing modes using Fixed Head Star Trackers and Fine Guidance Sensors, after successfully achieving coarse-pointing control using magnetometers.
Clapp, Brian R.↗
Robustness analysis applied to substructure controller synthesis
The stability and robustness of the controlled system obtained via the substructure control synthesis (SCS) method of Su et al. (1990) were examined using a six-bay truss model, and employing an LQG control design method to obtain controllers for two separate structures. It is found that the assembled controller provides a stability in this instance. A qualitative assessment of the stability robustness of the system with controller designed with the SCS method is provided by obtaining a controller using the complete truss model and comparing the robustness of the corresponding closed-loop systems.
Gonzalez-Oberdoerffer, Marcelo F.↗
The application of specific optimal control to the design of desensitized model following control systems
Desensitized linear servo model following feedback control systems design using specific optimal control concepts
Roy, R. J.↗
A technique for designing active control systems for astronomical telescope mirrors
This paper considers the problem of designing a control system to achieve and maintain the required surface accuracy of the primary mirror of a large space telescope. Control over the mirror surface is obtained through the application of a corrective force distribution by actuators located on the rear surface of the mirror. The design procedure is an extension of a model control technique developed for distributed parameter plants with known eigenfunctions to include plants whose eigenfunctions must be approximated by numerical techniques. Instructions are given for constructing the mathematical model of the system, and a design procedure is developed for use with. typical numerical data in selecting the number and location of the actuators. Examples of actuator patterns and their effect on various errors are given.
Active optics↗
Computer aided design of digital controller for radial active magnetic bearings
A five degree of freedom Active Magnetic Bearing (AMB) system is developed which is controlled by digital controllers. The model of the radial AMB system is linearized and the state equation is derived. Based on the state variables feedback theory, digital controllers are designed. The performance of the controllers are evaluated according to experimental results. The Computer Aided Design (CAD) method is used to design controllers for magnetic bearings. The controllers are implemented with a digital signal processing (DSP) system. The control algorithms are realized with real-time programs. It is very easy to change the controller by changing or modifying the programs. In order to identify the dynamic parameters of the controlled magnetic system, a special experiment was carried out. Also, the online Recursive Least Squares (RLS) parameter identification method is studied. It can be realized with the digital controllers. Online parameter identification is essential for the realization of an adaptive controller.
Cai, Zhong↗
Initial design and evaluation of automatic restructurable flight control system concepts
Results of efforts to develop automatic control design procedures for restructurable aircraft control systems is presented. The restructurable aircraft control problem involves designing a fault tolerance control system which can accommodate a wide variety of unanticipated aircraft failure. Under NASA sponsorship, many of the technologies which make such a system possible were developed and tested. Future work will focus on developing a methodology for integrating these technologies and demonstration of a complete system.
Weiss, J. L.↗
Active control transport design criteria
Vehicle design considerations for active control applications to subsonic transports are examined. Active control is defined along with those functions which are considered in the study of design criteria. The FAA regulations governing transport aircraft design are briefly discussed.
Hall, B. M.↗
An overview of the Hubble Space Telescope Pointing Control System design and operation
An overview of the Pointing Control System (PCS) design and operational scenarios, a description of the on-orbit performance, the problems encountered, and the resulting modifications that enhance the Hubble Space Telescope mission, are presented. The PCS provides the capability to maneuver the 24,000 lb telescope 90 deg in less than 18 minutes. It also provides the primary functions of attitude reference, attitude control and stabilization.
Andersen, G. C.↗
A computational technique for the design of a specific optimal controller.
Parametric input/output relation of approximate controller with optimized performance index, obtaining specific optimal control designed in regard to worst initial state
OPTIMAL CONTROL↗
A spacecraft attitude and articulation control system design for the Comet Halley intercept mission
An attitude and articulation control system design for the Comet Halley 1986 intercept mission is presented. A spacecraft dynamics model consisting of five hinge-connected rigid bodies is used to analyze the spacecraft attitude and articulation control system performance. Inertial and optical information are combined to generate scan platform pointing commands. The comprehensive spacecraft model has been developed into a digital computer simulation program, which provides performance characteristics and insight pertaining to the control and dynamics of a Halley Intercept spacecraft. It is shown that scan platform pointing error has a maximum value of 1.8 milliradians during the four minute closest approach interval. It is also shown that the jitter or scan platform pointing rate error would have a maximum value of 2.5 milliradians/second for the nominal 1000 km closest approach distance trajectory and associated environment model.
Key, R. W.↗
A new model performance index for the engineering design of control systems
New model performance index for engineering design of flight control systems
Rediess, H. A.↗
Mariner Mars 1969 navigation, guidance, and control
Design, mechanization, and flight tests for Mariner Mars 1969 navigation, guidance and control systems
Scull, J. R.↗
Maximum likelihood identifier refinements for F-8C adaptive control
Design refinement is described for baseline F-8C adaptive flight test control laws which consist of simplified quadratic-optimal model-following control structures in the pitch and lateral directional axes. The variable gains of both axes are adjusted adaptively by an explicit on-line maximum likelihood parameter identifier. The identifier, consisting of five parallel computing channels which evaluate the likelihood functions at discrete points in parameter space, operates in pitch only, using pitch rate, normal acceleration, and elevator position measurements.
Stein, G.↗
Phase A reaction control system design for the Large Space Telescope (LST)
The design of a reaction control system (RCS) for the Large Space Telescope is discussed. The primary requirement for the RCS is to serve as an emergency backup control system to the primary attitude control system. A regulated gaseous nitrogen RCS was selected. The operation of the system and its individual components is described. The principal design goals of the RCS were to minimize contamination effects, make use of existing components, and modularize the system to provide ease in manned orbital maintenance.
Price, W. B.↗