The complete Rayleigh-scattered field within a homogeneous plane-parallel atmosphere.
Complete Rayleigh scattered field within homogeneous plane parallel atmosphere, noting scalar transfer equation extension
ATMOSPHERIC SCATTERING↗
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Results for “Transfer Function”
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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Process of adaptation by the human controller
Model for detection, identification, and modification phases of process by which human operator adapts to changes in dynamics
DYNAMIC MODEL↗
Synthesis of active distributed RC networks.
Synthesis technique for RC network using two distributed RC elements, one negative impedance converter and one lumped capacitor
NETWORK SYNTHESIS↗
On the decoupling of multivariable systems.
Necessary and sufficient conditions for decoupling time-invariant linear multivariable system by state variable feedback, discussing transfer matrix consequences
MATRIX ALGEBRA↗
Structural and electromechanical interaction in the multiple-exciter technique for random vibration testing.
Random vibration testing by multiple electrodynamic exciter technique, analyzing electromechanics and structural feedback
POWER SPECTRUM↗
Rapid identification of linear and nonlinear systems.
Rapid parameter identification system for linear time-invariant plant with only input and output measurable
TRANSFER FUNCTION↗
A suboptimal approach to the control of systems containing uncertain parameters.
Linear optimal control in systems with uncertain parameters, noting application to design of compensating network for flexible booster for uncertain value of first bending mode
OPTIMAL CONTROL↗
Thin film heat transfer gage is stable at higher temperatures
Thin film convective heat transfer gage functions effectively for prolonged periods at temperatures up to 1000 degrees F. An initial resistance shift does not inhibit the performance or accuracy of the gages, as the original resistance-temperature relationship remains unchanged.
Loyd, J. R.↗
Approximate relations for laminar heat-transfer and shear-stress functions in equilibrium dissociated air
Approximate equations for computing enthalpy and velocity derivatives at surface of flat plate, cone, or blunt axisymmetric body
Zoby, E. V.↗
The Apollo Docking System
The Apollo docking system is the means by which the Apollo command and service modules and the lunar module are connected and disconnected during a lunar-landing mission. The system incorporates a CSM probe assembly that mates with a drogue assembly on the LM. Twelve automatic latches mounted on the CSM docking ring provide for structural integrity between the vehicles and for tunnel sealing during crew transfer. A functional description of the flight hardware and the alternate concepts that were evaluated to determine the system best suited to Apollo requirements are presented.
Kenneth A Bloom↗
Reachable sets for linear dynamical systems.
The properties of reachable sets for linear dynamical systems for specified control sets are discussed. Iterative procedures for determining numerical approximations of the reachable set are suggested and methods of obtaining an admissible control function which transfers an initial state to as near a prescribed target as possible is described. The problem of reachability with multiple control constraints is discussed and certain aspects of reachability for time-invariant systems with adjustable parameters is considered.
Pecsvaradi, T.↗
Texas applications system verification and transfer remote sensing information subsystem: Functional design
There are no author-identified significant results in this report.
Brown, M. L., Jr.↗
Performance of a magnetic multipole line-cusp argon ion thruster
A 17 cm diameter line cusp ion thruster was evaluated with inert gases which are candidate propellants for on orbit and orbit transfer propulsion functions for Large Space Systems. A semiempirical relationship was generated to predict thruster beam current in terms of plasma parameters which would allow initial thruster optimization without ion extraction and the associated large vacuum facilities. The sensitivity of performance to changes in discharge electrode configurations and magnetic circuit was evaluated and is presented. After final optimization a propellant utilization efficiency of 0.9 at a discharge chamber power expenditure of about 260 w per beam ampere was obtained. These performance parameters are the highest yet achieved with argon propellant.
Sovey, J. S.↗
Real time estimation of the heaving and pitching motions of a ship, using a Kalman filter
In the present study the estimation of the heave and pitch motion of a ship is considered, using Kalman filtering techniques. A significant part of the study is devoted to constructing appropriate models for the sea and the ship. The governing equations are obtained from hydrodynamic considerations in the form of linear differential equations with frequency dependent coefficients. In addition, nonminimum phase characteristics are obtained due to the spatial integration of the water wave forces. The resulting transfer matrix function is irrational and nonminimum phase. The conditions for a finite-dimensional approximation are considered and the impact of the various parameters is assessed. A numerical application is considered for a DD-963 destroyer.
Triantafyllou, M.↗
Real time estimation of ship motions using Kalman filtering techniques
The estimation of the heave, pitch, roll, sway, and yaw motions of a DD-963 destroyer is studied, using Kalman filtering techniques, for application in VTOL aircraft landing. The governing equations are obtained from hydrodynamic considerations in the form of linear differential equations with frequency dependent coefficients. In addition, nonminimum phase characteristics are obtained due to the spatial integration of the water wave forces. The resulting transfer matrix function is irrational and nonminimum phase. The conditions for a finite-dimensional approximation are considered and the impact of the various parameters is assessed. A detailed numerical application for a DD-963 destroyer is presented and simulations of the estimations obtained from Kalman filters are discussed.
Triantafyllou, M. S.↗
Effects of a rough boundary surface on polarization of the scattered field from an inhomogeneous medium
A combination of the standard Kirchhoff method for rough surface scattering with the Rayleigh phase function radiative transfer method for volume scattering is employed in the present study of the effect of surface roughness on the polarization of the scattered field. It is found that for pure surface scattering, the polarization ratio between zero and 20 deg incidence angles is sensitive to surface roughness change. When both surface and volume scattering are present, however, copolarization nulls by colatitude or degree of polarization at zero to 15 deg incidence angle, and copolarization or crosspolarization nulls by longitude at large incidence angles, are better indicators of surface roughness changes. It is noted that degree of polarization and copolarization nulls by colatitude vary monotonously with incidence angle, while in combined surface and volume scattering these have, respectively, a minimum and a maximum. This characteristic allows the separation of combined surface and volume scattering from pure surface or volume scattering.
Fung, A. K.↗
Expert system for on-board satellite scheduling and control
An Expert System is described which Rockwell Satellite and Space Electronics Division (S&SED) is developing to dynamically schedule the allocation of on-board satellite resources and activities. This expert system is the Satellite Controller. The resources to be scheduled include power, propellant and recording tape. The activities controlled include scheduling satellite functions such as sensor checkout and operation. The scheduling of these resources and activities is presently a labor intensive and time consuming ground operations task. Developing a schedule requires extensive knowledge of the system and subsystems operations, operational constraints, and satellite design and configuration. This scheduling process requires highly trained experts anywhere from several hours to several weeks to accomplish. The process is done through brute force, that is examining cryptic mnemonic data off line to interpret the health and status of the satellite. Then schedules are formulated either as the result of practical operator experience or heuristics - that is rules of thumb. Orbital operations must become more productive in the future to reduce life cycle costs and decrease dependence on ground control. This reduction is required to increase autonomy and survivability of future systems. The design of future satellites require that the scheduling function be transferred from ground to on board systems.
Barry, John M.↗
Construction and parameterization of all static and dynamic H2-optimal state feedback solutions, optimal fixed modes, and fixed decoupling zeros
This paper considers an H2 optimization problem via state feedback. The class of problems dealt with here are general singular type which have a left invertible transfer matrix function from the control input to the controlled output. This class subsumes the regular H2 optimization problems. The paper constructs and parameterizes all the static and dynamic H2 optimal state feedback solutions. Moreover, all the eigenvalues of an optimal closed-loop system are characterized. All optimal closed-loop systems share a set of eigenvalues which are termed here as the optimal fixed modes. Every H2 optimal controller must assign among the closed-loop eigenvalues the set of optimal fixed modes. This set of optimal fixed modes includes a set of optimal fixed decoupling zeros which shows the minimum absolutely necessary number and locations of pole-zero cancellations present in any H2 optimal design. It is shown that both the sets of optimal fixed modes and optimal fixed decoupling zeros do not vary depending upon whether the static or the dynamic controllers are used.
Chen, Ben M.↗