Apollo spacecraft control systems
Engine and attitude control systems for Apollo spacecraft
APOLLO SPACECRAFT↗
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Results for “System control”
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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Control-system techniques for improved departure/spin resistance for fighter aircraft
This paper summarizes some fundamental information on control-system effects on controllability of highly maneuverable aircraft at high angles of attack and techniques for enhancing fighter aircraft departure/spin resistance using control-system design. The discussion includes (1) a brief review of pertinent high-angle-of-attack phenomena including aerodynamics, inertia coupling, and kinematic coupling, (2) effects of conventional stability augmentation systems at high angle of attack, (3) high-angle-of-attack control-system concepts designed to enhance departure/spin resistance, and (4) the outlook for applications of these concepts to future fighters, particularly those designs which incorporate relaxed static stability.
High angle of attack↗
Biological control system - a critical review and evaluation, developments in manual control
Biocontrol systems - mathematical models for human manual control system through computer simulation and servoanalysis
BIOCONTROL SYSTEM↗
Electromechanical propellant control system actuator
New control mechanism technologies are currently being sought to provide alternatives to hydraulic actuation systems. The Propulsion Laboratory at Marshall Space Flight Center (MSFC) is involved in the development of electromechanical actuators (EMA's) for this purpose. Through this effort, an in-house designed electromechanical propellant valve actuator has been assembled and is presently being evaluated. This evaluation will allow performance comparisons between EMA and hydraulics systems. The in-house design consists of the following hardware: a three-phase brushless motor, a harmonic drive, and an output spline which will mate with current Space Shuttle Main Engine (SSME) propellant control valves. A resolver and associated electronics supply position feedback for the EMA. System control is provided by a solid-state electronic controller and power supply. Frequency response testing has been performed with further testing planned as hardware and test facilities become available.
Myers, W. Neill↗
Control System Damps Vibrations
New control system damps vibrations in rotating equipment with help of phase-locked-loop techniques. Vibrational modes are controlled by applying suitable currents to drive motor. Control signals are derived from sensors mounted on equipment.
Kopf, E. H., Jr.↗
Pterodactyl: Guidance and Control of a Symmetric Deployable Entry Vehicle using an Aerodynamic Control System
The NASA-funded Pterodactyl project seeks to advance the state-of-the-art for varying entry vehicle types by developing unconventional guidance and control technologies for Deployable Entry Vehicles (DEVs) that can be applied to different entry vehicle configurations. Prior work by the authors [1–5] involved developing both traditional and novel integrated guidance and control solutions for a Pterodactyl Baseline Vehicle (PBV), a variant of an asymmetric DEV called the Lifting Nano ADEPT (LNA) [6]. In the prior studies, two different guidance schemes were designed and implemented for the PBV: (i) traditional bank angle guidance developed using the Fully Numerical Predictor-Corrector Entry Guidance (FNPEG) and (ii) novel angle of attack and sideslip (α - β) guidance developed using FNPEG with Uncoupled Range Control [4]. Using Linear Quadratic Regulator (LQR) optimal control methods with state-feedback integral control designs, these guidance trajectories were designed to be tracked using (i) a conventional propulsive entry vehicle control hardware architecture - reaction control systems (RCS) and (ii) novel non-propulsive entry vehicle control systems - aerodynamic flap control system (FCS) and moving mass control system (MMCS) [1]. The novel FCS and MMCS architectures were designed to track α - β guidance commands while the RCS was designed to track bank angle commands. It was discovered that the asymmetric DEV, the PBV, experienced a non-zero induced roll moment due to sideslip that the FCS and MMCS architectures had limited capability to trim out. These two architectures were designed to provide independent angle of attack and sideslip commands with limited consideration for roll moment generation to trim. As a result, for the PBV, the FCS and MMCS configurations as designed, were limited in providing the control authority needed to track an α - β guidance trajectory [1]. These results form the motivation for the work presented in this paper - utilizing an aerodynamic control system to track α - β guidance commands for a symmetric DEV with the expectation that a symmetric entry vehicle will have zero or significantly reduced roll moment due to sideslip that the FCS can handle when tracking an α - β guidance trajectory. To demonstrate the feasibility of a novel guidance and control architecture on a DEV, we utilize a symmetric DEV, the PBV-II, for (i) the novel α - β guidance development using FNPEG with Uncoupled Range Control and (ii) LQR control design using eight aerodynamic control surfaces. This paper demonstrates that the novel uncoupled α - β guidance tracking can be achieved using aerodynamic control surfaces on a symmetric deployable entry vehicle configuration.
Wendy A Okolo↗
NASA B737 flight test results of the total energy control system
The Total Energy Control System (TECS) is an integrated autopilot/autothrottle developed by BCAC that was test flown on NASA Langley's Transport System Research Vehicle (i.e., a highly modified Boeing B737). This systems was developed using principles of total energy in which the total kinetic and potential energy of the airplane was controlled by the throttles, and the energy distribution controled by the elevator. TECS integrates all the control functions of a conventional pitch autopilot and autothrottle into a single generalized control concept. This integration provides decoupled flightpath and maneuver control, as well as a coordinated throttle response for all maneuvers. A mode hierarchy was established to preclude exceeding airplane safety and performance limits. The flight test of TECS took place as a series of five flights over a 33-week period during September 1985 at NASA Langley. Most of the original flight test plan was completed within the first three flights with the system not exhibiting any instabilities or design problems that required any gain adjustment during flight.
Bruce, Kevin R.↗
Quantization error in the design of digital control systems.
Quantization error effect for digital control system design
OPTIMAL CONTROL↗
Reconfiguration control system for an aircraft wing
Independently deflectable control surfaces are located on the trailing edge of the wing of a blended wing-body aircraft. The reconfiguration control system of the present invention controls the deflection of each control surface to optimize the spanwise lift distribution across the wing for each of several flight conditions, e.g., cruise, pitch maneuver, and high lift at low speed. The control surfaces are deflected and reconfigured to their predetermined optimal positions when the aircraft is in each of the aforementioned flight conditions. With respect to cruise, the reconfiguration control system will maximize the lift to drag ratio and keep the aircraft trimmed at a stable angle of attack. In a pitch maneuver, the control surfaces are deflected to pitch the aircraft and increase lift. Moreover, this increased lift has its spanwise center of pressure shifted inboard relative to its location for cruise. This inboard shifting reduces the increased bending moment about the aircraft's x-axis occasioned by the increased pitch force acting normal to the wing. To optimize high lift at low speed, during take-off and landing for example, the control surfaces are reconfigured to increase the local maximum coefficient of lift at stall-critical spanwise locations while providing pitch trim with control surfaces that are not stall critical.
Wakayama, Sean R.↗
A method of synthesis of controlled systems
Differential equations describing closed control systems
PROBLEM SOLVING↗
On stability in control systems.
Stability definitions for generalized control systems
CONTROL STABILITY↗
Flight evaluation of advanced control systems and displays on a general aviation airplane
A flight-test program was conducted to determine the effect of advanced flight control systems and displays on the handling qualities of a light twin-engined airplane. A flight-director display and an attitude-command control system, used separately and in combination, transformed a vehicle with poor handling qualities during ILS approaches in turbulent air into a vehicle with good handling qualities. The attitude-command control system also improved the ride qualities of the airplane. A rate-command control system made only small improvements to the airplane's ILS handling qualities in turbulence. Both the rate- and the attitude-command control systems reduced stall warning in the test airplane, increasing the likelihood of inadvertent stalls. The final approach to the point of flare was improved by both the rate- and the attitude-command control systems. However, the small control wheel deflections necessary to flare were unnatural and tended to cause overcontrolling during flare. Airplane handling qualities are summarized for each control-system and display configuration.
Loschke, P. C.↗
Stability in general control systems.
Axiomatic approach to control system theory as generalization of dynamic systems, noting weak and strong stability and Liapunov function
LIAPUNOV FUNCTION↗
Control systems synthesis for a large flexible space antenna
The problem of control systems synthesis is considered for controlling the rigid-body attitude and elastic motion of a large deployable space-based antenna. Two methods for control systems synthesis are considered. The first method utilizes the stability and robustness properties of the controller consisting of torque actuators and collocated attitude and rate sensors. The second method is based on the linear-quadratic-Gaussian (LQG) control theory. A combination of the two methods, which results in a two-level hierarchical control system, is also briefly discussed. The performance of the controllers is analyzed by computing the variances of pointing errors, feed misalignment errors and surface contour errors in the presence of sensor and actuator noise.
Joshi, S. M.↗
Stability analysis methods for hybrid control systems.
Stability margins for hybrid continuous discrete data control systems, developing open loop transfer function
TRANSFER FUNCTION↗
Lunar Orbiter Attitude Control System.
Lunar Orbiter Attitude Control System design and space flight performance
SPACECRAFT DESIGN↗
Analysis of the TDRS multiple access system for possible use as an attitude control system sensor
A member of the constellation of TDR satellites (TDRS) has experienced a failure of its prime earth sensor. Failure of the remaining earth sensor could result in the inability of the satellite to control its attitude and provide user services. Loss of the satellite would be a serious event. The multiple access (MA) antenna array on the TDRS has been proposed for use as a backup sensor for the attitude control system. This paper describes our analysis of the performance of the MA array as an interferometer used for accurate attitude determination. A least squares fit of a plane to the MA phase information appears to represent the TDRS body roll and pitch within about 0.1 deg. This is sufficient for SGL pointing and MA and SSA user services. Analytic improvements that include ionospheric correction may yield sufficient accuracy for KSA user services.
Blevins, Bruce Allyn↗
Ares I Flight Control System Overview
This paper describes the control challenges posed by the Ares I vehicle, the flight control system design and performance analyses used to test and verify the design. The major challenges in developing the control system are structural dynamics, dynamic effects from the powerful first stage booster, aerodynamics, first stage separation and large uncertainties in the dynamic models for all these. Classical control techniques were employed using innovative methods for structural mode filter design and an anti-drift feature to compensate for translational and rotational disturbances. This design was coded into an integrated vehicle flight simulation and tested by Monte Carlo methods. The product of this effort is a linear, robust controller design that is easy to implement, verify and test.
Hall, Charles↗