File:Implementation of optimal controls using conventional control systems (IA implementationof1094549798).pdf

This thesis investigates the implementation of optimal control solutions for positioning spacecraft antenna using conventional techniques. Conventional maneuvers consider each axis independently and may include artificial limits that reduce the efficiency of the system. These methods allow simple, but generally suboptimal, maneuver design. Multi-body dynamic systems do, however, exhibit coupling effects that can be advantageous for enhancing motion planning. Including coupling effects in the model can reduce energy needed to implement a slew maneuver. For example, previous work demonstrated that optimal control solutions can reduce required slew time for spacecraft antenna maneuvers. This work explores the utility of implementing such optimal trajectories as reference maneuvers using current control schemes. Development and validation of the approach is explored using systems of increasing dynamic complexity. Two methods to match given optimal control profiles using existing control logic were developed and compared against current practice. The developed methods were applied to the results for a double gimbal model and the Tracking Data Relay Satellite. The developed approach allows optimal trajectories to be successfully matched to within 2% position error along the trajectory using less than four conventional maneuvers. These results thus provide a simplified approach for implanting optimal slew maneuvers.

Subjects: Optimal Slew Maneuvers; Spacecraft; Antenna; Communications Satellite; Multi-body Dynamics; Dynamic Coupling; Optimal Control; Double Gimbal