Low-Thrust Spacecraft Attitude Control for Solar Alignment
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Solution Overview
Problem
Conventional methods for controlling the attitude of low-thrust propulsion vehicles during orbital maneuvers face inefficiencies in maintaining solar power generation while avoiding snap-roll events, leading to reduced energy supply and prolonged transfer times.
Innovation Solution
A multi-step process involving generating a nominal attitude profile, identifying snap-roll events, defining control points, formulating a cost function to minimize solar power losses, and interpolating angular rates to optimize the orbital trajectory, ensuring efficient solar power generation without increasing transfer time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the vehicle maintains solar alignment during orbital transfer, then solar power generation is maximized, but snap-roll events occur violating angular rate constraints
Solution Approach 1:
The system performs preliminary identification of snap-roll events by analyzing the attitude profile before execution, detecting conditions where solar vector and thrust vector alignment would cause angular rate violations. By identifying these events in advance, the system can prepare corrective angular velocity adjustments without compromising solar power generation during the actual maneuver.
2Reliability
If the vehicle adjusts attitude to avoid snap-roll events, then angular rate constraints are satisfied, but solar power generation is reduced
Solution Approach 1:
The system employs feedback by continuously monitoring the attitude profile and comparing it against identified snap-roll events. When a snap-roll event is detected, the system generates corrective instructions that adjust angular velocity while minimizing deviation from the optimal solar alignment attitude profile. This closed-loop approach ensures constraint satisfaction while maintaining maximum solar power generation.
3Device complexity
If the vehicle uses conventional attitude control methods, then simplicity is maintained, but transfer time is prolonged due to energy losses
Solution Approach 1:
The attitude control process is segmented into distinct operational phases: nominal attitude profile generation, snap-roll event identification, control point definition, and corrective instruction generation. This segmentation allows the system to apply complex optimization only when necessary (during identified snap-roll events) while maintaining simple conventional control during normal operations, thus reducing overall transfer time without excessive complexity.
Data Source
AI summary
A vehicle capable of computing an optimal attitude path that provides increased solar power generation through snap-roll events during orbital transfer maneuvers. A vehicle may include a memory and processor, including instructions that, when executed, can generate an attitude profile of the vehicle during an orbital transfer; identify, from the attitude profile, a snap-roll event, the snap-roll event is a violation event in which movement of the vehicle violates a body-frame angular rate constraint, wherein the snap-roll event is identified based on the first vector and the second vector being in substantial alignment; identify a plurality of control points along a trajectory of the vehicle during the snap-roll event; and adjust angular velocity of the vehicle at a first control point in the plurality of control points, wherein a first angular velocity of the vehicle at the first control point exceeds a maximum angular velocity of the vehicle.