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Price, Douglas B.

Publications and source records attributed to Price, Douglas B..

8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

The Coherent Launchsite Wind Sounder (CLAWS)

This talk will provide a description of the Coherent Launchsite Wind Sounder (CLAWS) program for the development of a near real-time launchsite wind measurement system. The CLAWS program was motivated by the need to have wind measurements for spacecraft launch systems that are more timely than those from balloons. and that measure the winds along the booster's flight path. This program went from conceptual development to the testing of a breadboard system at KSC in concert with the launch of STS-48 in September of 1991. The system demonstrated the capability to measure the wind field, that a launch vehicle will traverse, from ground level to an altitude of 26 Km in approximately six minutes. The presentation will cover the concept, the hardware and the algorithms required, the test program and some results from the CLAWS system.

Price, Douglas B.↗
NASA NTRS1992

An integrated controls-structures design methodology for a flexible spacecraft

This paper proposes an approach for the design of flexible spacecraft, wherein the structural design and the control system design are performed simultaneously. The integrated design problem is posed as an optimization problem in which both the structural parameters and the control system parameters constitute the design variables, which are used to optimize a common objective function, thereby resulting in an optimal overall design. The approach is demonstrated by application to the integrated design of a geostationary platform, and to a ground-based flexible structure experiment. The numerical results obtained indicate that the integrated design approach generally yields spacecraft designs that are substantially superior compared to the conventional approach, wherein the structural design and control design are performed sequentially.

Maghami, Peiman G.↗
NASA NTRS1988

Singular perturbations and time scales in the design of digital flight control systems

The results are presented of application of the methodology of Singular Perturbations and Time Scales (SPATS) to the control of digital flight systems. A block diagonalization method is described to decouple a full order, two time (slow and fast) scale, discrete control system into reduced order slow and fast subsystems. Basic properties and numerical aspects of the method are discussed. A composite, closed-loop, suboptimal control system is constructed as the sum of the slow and fast optimal feedback controls. The application of this technique to an aircraft model shows close agreement between the exact solutions and the decoupled (or composite) solutions. The main advantage of the method is the considerable reduction in the overall computational requirements for the evaluation of optimal guidance and control laws. The significance of the results is that it can be used for real time, onboard simulation. A brief survey is also presented of digital flight systems.

Naidu, Desineni S.↗
NASA NTRS1988

Adaptive guidance for an aero-assisted boost vehicle

An adaptive guidance system incorporating dynamic pressure constraint is studied for a single stage to low earth orbit (LEO) aero-assist booster with thrust gimbal angle as the control variable. To derive an adaptive guidance law, cubic spline functions are used to represent the ascent profile. The booster flight to LEO is divided into initial and terminal phases. In the initial phase, the ascent profile is continuously updated to maximize the performance of the boost vehicle enroute. A linear feedback control is used in the terminal phase to guide the aero-assisted booster onto the desired LEO. The computer simulation of the vehicle dynamics considers a rotating spherical earth, inverse square (Newtonian) gravity field and an exponential model for the earth's atmospheric density. This adaptive guidance algorithm is capable of handling large deviations in both atmospheric conditions and modeling uncertainties, while ensuring maximum booster performance.

Pamadi, Bandu N.↗
NASA NTRS1987

Technology development program for twenty-first century aerospace vehicles

A program to meet the avionics technology needs for the design of future space transportation systems is presented. The program is designed to meet as many technology goals as possible by 1996 so decisions can be made as to which vehicles are feasible and which should be constructed.

Suit, William T.↗