FEASIBILITY STUDY OF NEW TECHNIQUES FOR CONTROL OF RE-ENTRY VEHICLES. VOL. 1. CALCULATION OF OPTIMAL TRAJECTORIES AND SYNTHESIS OF CONTROL FUNCTIONS
HONEYWELL INC MINNEAPOLIS MN MILITARY PRODUCTS GROUP
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Optimization techniques are used to synthesize the control programs and compute the corresponding flight paths for controllable re-entry vehicles. Linear perturbation control about these reference trajectories is investigated. A large portion of the theory of the calculus of variations is modified and extended to apply to this problem. Many details of computational techniques, necessary in the adaptation of the theory to large scale digital calculation, are reported. The optimization method which evolves is a modification of a Newton -Raphson iteration, although gradient procedures are also studied. The criteria for re-entry trajectories are functionals of the motion related to the heating of the vehicle. It is found that these criteria are relatively insensitive to the flight path, and this fact leads to computational problems which must be handled carefully. The paths and control authority are constrained by reasonable physical requirements. The linear perturbational control is found by requiring the integral of the square of the control deviation to be minimum. The vehicle position is the object of control in the cases studied. It is found that this form of control can be used throughout the entire re-entry corridor. Various modifications of the control gain program at the end of the trajectory are considered.
- Spacecraft Trajectories and Reentry