A combined attitude and sun tracking system for spacecraft using fuzzy logic control
Many spacecraft attitude control systems today use reaction wheels to deliver precise torques to achieve a three-axis attitude stabilization. Despite the extensive studies in attitude controllers, failures still can occur in a spacecraft system. For example, if a spacec...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
2019
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/84366/1/FK%202019%20118%20-%20ir.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Many spacecraft attitude control systems today use reaction wheels to deliver precise torques to
achieve a three-axis attitude stabilization. Despite the extensive studies in attitude
controllers, failures still can occur in a spacecraft system. For example, if a
spacecraft suffers multiple reaction wheel failure, external disturbances will cause the spacecraft
to tumble and lose its ability to correct the attitude error. If the failure is
irrecoverable, it may cause the spacecraft to spin uncontrollably and jeopardize the
space mission. The most common way to recover a tumbling spacecraft is by firing
chemical thrusters sequentially to generate a torque, which can control the total
momentum of the spacecraft. Since the thrusters expel reaction mass to produce a
torque, this leads to increased fuel consumption and eventually shortened operational life.
Most spacecraft have their solar arrays mounted on the y-axis and oriented
perpendicular to the sun to receive the maximum amount of solar energy. The solar
arrays are rotated using Solar Array Drive Assemblies to track the sun. As a result of the
rotations of the solar arrays, internal torques are generated. The main objective in this research
is to design a combined attitude and sun tracking system (CASTS) that can utilize the internal
torques produced by the solar arrays for attitude control while tracking the sun simultaneously.
Two mechanisms are proposed for the CASTS to generate the internal control torque by
rotating the solar arrays at different angular speeds. In order to counteract the external
disturbance torque, several non-fuzzy logic and fuzzy logic controllers are designed for CASTS. The
performance of the proposed CASTS control strategy is tested through numerical simulations.
The findings show that all fuzzy logic-based control schemes are able to achieve smaller pitch
angle errors compared to the non-fuzzy logic controllers. Overall, the research results show that
the proposed CASTS control strategy is effective for controlling the spacecraft attitude and
tracking the sun simultaneously. |
|---|