Developing and implementing a CubeSat's equations of motion

Fuente: arXiv
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Auteurs principaux: Wheen, Liam, Benjamin, Oscar
Format: Preprint
Publié: 2024
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author Wheen, Liam
Benjamin, Oscar
author_facet Wheen, Liam
Benjamin, Oscar
contents As part of the Bristol PROVE mission, a nano satellite in low Earth orbit will be required to track a ground based target during a 400 second flyover. This requires agile attitude control that will be achieved using a system of flywheels. To calculate the necessary torque from these flywheels, a controller was designed. Using newly derived equations of motion for the system, an expression to optimise the gains was produced. With this controller, simulations were run to evaluate the largest causes of error in target pointing. Disturbance torques were safely handled by the controller, but led to a 12% increase in wheel speeds, reaching 8325 rpm. This higher speed led to an increased gyroscopic torque, reaching 10^-7 Nm in the worst case. However since the flywheels can deliver 10^-5 Nm of torque, the controller could also correct for this. Hardware performance was then varied to assess the effect of each component on pointing accuracy. Attitude sensor noise was found to increase pointing error by 1.9 degrees in the worst case. Minimum performance requirements were then determined for each component in order to maintain an acceptable pointing accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2408_00176
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Developing and implementing a CubeSat's equations of motion
Wheen, Liam
Benjamin, Oscar
Instrumentation and Methods for Astrophysics
As part of the Bristol PROVE mission, a nano satellite in low Earth orbit will be required to track a ground based target during a 400 second flyover. This requires agile attitude control that will be achieved using a system of flywheels. To calculate the necessary torque from these flywheels, a controller was designed. Using newly derived equations of motion for the system, an expression to optimise the gains was produced. With this controller, simulations were run to evaluate the largest causes of error in target pointing. Disturbance torques were safely handled by the controller, but led to a 12% increase in wheel speeds, reaching 8325 rpm. This higher speed led to an increased gyroscopic torque, reaching 10^-7 Nm in the worst case. However since the flywheels can deliver 10^-5 Nm of torque, the controller could also correct for this. Hardware performance was then varied to assess the effect of each component on pointing accuracy. Attitude sensor noise was found to increase pointing error by 1.9 degrees in the worst case. Minimum performance requirements were then determined for each component in order to maintain an acceptable pointing accuracy.
title Developing and implementing a CubeSat's equations of motion
topic Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2408.00176