Re-Entry Vehicle Control System Design and Mechanization
Report Number: AFFDL TR 66-3
Author(s): Scharmack, D. K., Ward, M. D.
Corporate Author(s): Honeywell, Inc.
Laboratory: Air Force Flight Dynamics Laboratory
Date of Publication: 1966-04
Pages: 210
Contract: AF 33(615)-1858
DoD Project: 8225
DoD Task: 822501
Identifier: AD0485616
Abstract:
A nonlinear optimal feedback control scheme for controlling a vehicle re-entering the earth's atmosphere from lunar return initial conditions is reported. The optimal feedback control law used in the scheme is obtained from a multi-dimensional surface fit of the control function for several optimal trajectories. Partials of the control with respect to the state vector are included in the fitting procedure. The functional minimized by the trajectories is the total (convective plus radiative) stagnation point heat. The feedback control scheme is developed, and several re-entry trajectories are simulated. Modest increasing total heat from optimal values are observed, and large (although tolerable) terminal point errors occur. It is believed that the terminal errors can be greatly reduced, if necessary. A powerful predictor scheme is developed which allows optimal a function of a parameter. This is used to extend the range of an optimal trajectory, to perform an absolute minimum test, and to map the optimal re-entry corridor. Sufficiency tests for a relative minimum are mechanized, and it is shown that the trajectories considered are minimizing paths.
Provenance: Lockheed Martin Missiles & Fire Control
Author(s): Scharmack, D. K., Ward, M. D.
Corporate Author(s): Honeywell, Inc.
Laboratory: Air Force Flight Dynamics Laboratory
Date of Publication: 1966-04
Pages: 210
Contract: AF 33(615)-1858
DoD Project: 8225
DoD Task: 822501
Identifier: AD0485616
Abstract:
A nonlinear optimal feedback control scheme for controlling a vehicle re-entering the earth's atmosphere from lunar return initial conditions is reported. The optimal feedback control law used in the scheme is obtained from a multi-dimensional surface fit of the control function for several optimal trajectories. Partials of the control with respect to the state vector are included in the fitting procedure. The functional minimized by the trajectories is the total (convective plus radiative) stagnation point heat. The feedback control scheme is developed, and several re-entry trajectories are simulated. Modest increasing total heat from optimal values are observed, and large (although tolerable) terminal point errors occur. It is believed that the terminal errors can be greatly reduced, if necessary. A powerful predictor scheme is developed which allows optimal a function of a parameter. This is used to extend the range of an optimal trajectory, to perform an absolute minimum test, and to map the optimal re-entry corridor. Sufficiency tests for a relative minimum are mechanized, and it is shown that the trajectories considered are minimizing paths.
Provenance: Lockheed Martin Missiles & Fire Control