Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

expensive than a single analysis. It is therefore mandatory to find methods that evaluate aerodynamic functions and their gradient
at the lowest possible computational cost, as well as fast and robust optimization methods. Classical optimization techniques
(descent methods) not only require the value of the function to optimize, but also of its gradient. The classical way to compute
the gradient is to use a finite-difference formula; the main drawback of this method is due to the fact that n + 1 evaluations of
aerodynamic functions are necessary at each iteration, n being the number of parameters defining the geometry to optimize. So,
such methods are completely un-suited to aerodynamic shape optimization, because of the high computational cost of the single
analysis. Alternative methods (stochastic optimization, genetic algorithms) that don#t require gradient information are also highly
costly in term of CPU time. For a few years, techniques for sensitivity analysis based on the optimal control theory have been
developed. These techniques derive from the state equations another set of equations called ”adjoint” or ”costate” equations. The
solution of these adjoint equations is used to compute the gradient at very low cost; since solving the adjoint equations is equivalent
to solve the state equations, the cost of sensitivity analysis is greatly reduced. Some authors use adjoint equations derived from
the discretized Euler equations. In this paper, we focus on adjoint equations derived from analytical state equations.
Author
Control Theory; Optimal Control; Two Dimensional Models; Aerodynamic Configurations; Viscous Flow; Shapes; Genetic Algorithms
20000063535 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA USA
Biomorphic Explorers Leading Towards a Robotic Ecology
Thakoor, Sarita, Jet Propulsion Lab., California Inst. of Tech., USA; Miralles, Carlos, AeroVironment, Inc., USA; Chao, Tien-
Hsin, Jet Propulsion Lab., California Inst. of Tech., USA; [1999]; 23p; In English; DARPA/ISAT Study Meeting: Towards a
Robotic Ecology, 26-27 Apr. 1999, Cambridge, MA, USA; Sponsored by Defense Advanced Research Projects Agency, USA;
No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche
This paper presents viewgraphs of biomorphic explorers as they provide extended survival and useful life of robots in ecology.
The topics include: 1) Biomorphic Explorers; 2) Advanced Mobility for Biomorphic Explorers; 3) Biomorphic Explorers: Size
Based Classification; 4) Biomorphic Explorers: Classification (Based on Mobility and Ambient Environment); 5) Biomorphic
Flight Systems: Vision; 6) Biomorphic Glider Deployment Concept: Larger Glider Deploy/Local Relay; 7) Biomorphic Glider
Deployment Concept: Balloon Deploy/Dual Relay; 8) Biomorphic Exlplorer: Conceptual Design; 9) Biomorphic Gliders; and
10) Applications.
CASI
Ecology; Robotics; Biology
20000063536 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA USA
Biomorphic Explorers
Thakoor, Sarita, Jet Propulsion Lab., California Inst. of Tech., USA; [1999]; 19p; In English; Biologically Inspired Approaches
for MAV’s, 21-22 Apr. 1999, Alexandria, VA, USA; Sponsored by Defense Advanced Research Projects Agency, USA; No Copyright;
Avail: CASI; A03, Hardcopy; A01, Microfiche
This paper presents, in viewgraph form, the first NASA/JPL workshop on Biomorphic Explorers for future missions. The
topics include: 1) Biomorphic Explorers: Classification (Based on Mobility and Ambient Environment); 2) Biomorphic Flight
Systems: Vision; 3) Biomorphic Explorer: Conceptual Design; 4) Biomorphic Gliders; 5) Summary and Roadmap; 6) Coordinated/Cooperative
Exploration Scenario; and 7) Applications. This paper also presents illustrations of the various biomorphic
explorers.
CASI
Biology; Animals; Classifications; Wildlife; Aerodynamics
20000064074 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA USA
Mars Rover Navigation Results Using Sun Sensor Heading Determination
Volpe, Richard, Jet Propulsion Lab., California Inst. of Tech., USA; [1998]; 8p; In English; No Copyright; Avail: CASI; A02,
Hardcopy; A01, Microfiche
Upcoming missions to the surface of Mars will use mobile robots to traverse long distances from the landing site. to prepare
for these missions, the prototype rover, Rocky 7, has been tested in desert field trials conducted with a team of planetary scientists.
While several new capabilities have been demonstrated, foremost among these was sun-sensor based traversal of natural terrain
totaling a distance of one kilometer. This paper describes navigation results obtained in the field tests, where cross-track error was
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