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Kamm, J. L.

Publications and source records attributed to Kamm, J. L..

7 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

A nonlinear programming approach for optimizing two-stage lifting vehicle ascent to orbit

An optimal atmospheric flight branched trajectory-shaping capability is presented based on the Davidon-Fletcher-Powell variable metric parameter optimization technique. Gradient information is generated using finite difference methods. A typical atmospheric flight branched optimization problem is analyzed which requires the determination of 31 parameters. This parameter set includes the three-dimensional description of vehicle attitude control angles for three branches of flight: first-stage ascent, second-stage ascent, and first-stage flyback. The important inflight inequality contraints required to maintain the integrity of the vehicles are considered. Some of the numerical methods employed are discussed, along with several new auxiliary techniques developed to improve the compatibility of the numerical gradient and iterator.

Kamm, J. L.↗
NASA NTRS1973

Accelerating one-dimensional searches.

In the search technique presented, the number of function evaluations is reduced by making use of the derivative of the function. The search method is combined with the variable metric algorithm reported by Davidon (1959) to solve a 17-parameter optimal atmospheric flight of a space shuttle vehicle. In the case of the problem, the proposed method requires one or two function evaluations per iteration less than the standard cubic fit-golden section method.

Johnson, I. L., Jr.↗
NASA NTRS1972

Constrained optimal ascent-flyback shuttle trajectories.

An optimal Space Shuttle ascent-flyback trajectory shaping capability is presented which is based on the accelerated gradient parameter optimization technique. A typical atmospheric flight branched optimization problem is analyzed which required the determination of 31 parameters. This parameter set includes the description of the vehicle attitude control angles for three branches of Shuttle flight: first stage ascent, second stage ascent, and first stage flyback. The important in-flight inequality constraints required to maintain the integrity of the vehicle are considered. Results indicate that for a launch into a 55 deg inclined ellipse, a 13% increase in payload can be realized by using optimal control in the first-stage ascent rather than the conventional gravity-turn steering.

Kamm, J. L.↗