Diapositiva 1
Single-slew manoeuvres for spin-stabilized spacecraft29th March
2011James BiggsGlasgowIn collaboration withNadjim Horri at the
Surrey Space Centre6th International Workshop and Advanced
SchoolSpaceflight Dynamics and
Controlwww.strath.ac.uk/[email protected]
and nano spacecraft seen as viable alternatives to larger
spacecraft for certain missions e.g. Enable rapid space access.
29th March 20112James BiggsIntroduction
Motion Planning
Reduction method
Practicalcost function
Example
Conclusion
SSTL-150 UKube 1 Clydespace andStrathclyde University Use an
arrow like this to mark current sectionAttitude ModesTwo vital
mission phases:-
De-tumbling and stabilisation initial tip-off speeds (worst case
scenario for Ukube -5rpm in every axis .) Tumbling motion must be
stabilised or mission will fail. B dot control has been
demonstrated.
Re-pointing and stabilisation reorient spacecraft to target
specific point (e.g. point antenna to ground station, point solar
cells towards sun for maximum power.) Accurate re-pointing is yet
to be realised .
This presentation proposes a method for re-pointing.
29th March 20113James Biggs
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current
sectionStabilizationTwo conventional methods:-
Spin stabilization passive, re-pointing required.Early
satellites NASA Pioneer 10/11, Galileo Jupiter orbiter
Three axis-stabilization active control.Thrusters, reaction
wheels on conventional spacecraft.
Spin stabilization is attractive for nano-spacecraft Enables
temporary GNC switch off.
29th March 20114James BiggsIntroduction
Motion Planning
Reduction method
Practicalcost function
Example
Conclusion
Use an arrow like this to mark current sectionRe-pointing spin
stabilized spacecraftPossibility:-
Spin down, perform an eigen-axis rotation, spin up.
Computationally easy to plan and track.
may not be feasible with small torques of micro/nano spacecraft
in a specified time.
Requires better planning/design of reference trajectory.
29th March 20115James Biggs
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 20116James Biggs
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 20117James Biggs
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 20118James BiggsMotion Planning using optimal
controlKinematic constraint:
Subject to the cost function:
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 20119Insert Name as Header & Footer
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 201110James Biggs
Sketch of proof Kinematic constraintIntroduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 201111James Biggs
Sketch of proof Use a Lie group formulationIntroduction
Motion Planning
Reduction method
Practicalcost function
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ConclusionUse an arrow like this to mark current section29th
March 201112James BiggsSketch of proof - Construct the
left-invariant Hamiltonian (Jurdjevic, V., Geometric Control
Theory, 2002)
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 201113James BiggsSketch of proof - Construct the
left-invariant Hamiltonian vector fields and solve:
Solve the differential equations:
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 201114James BiggsSketch of proof.Lax Pair Integration:
Solve for a particular initial condition
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 201115James Biggs
Practical cost function 1Minimise the final pointing
direction:Introduction
Motion Planning
Reduction method
Practicalcost function
Example
Conclusion
Use an arrow like this to mark current section29th March
201116James BiggsPractical cost function 2
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionMinimize J by optimizing available parameters:Minimize
torque requirement amongst reduced kinematic motions:Use an arrow
like this to mark current section29th March 201117James
Biggsexample
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionSSTL-100 Use an arrow like this to mark current
section29th March 201118James Biggsexample
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionSSTL-100 Use an arrow like this to mark current
section29th March 201119Insert Name as Header & Footer
Control Torque History (Nm)Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 201120James Biggs
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
ConclusionUse an arrow like this to mark current section29th
March 201121James BiggsIntroduction
Motion Planning
Reduction method
Practicalcost function
Example
Conclusion
Use an arrow like this to mark current sectionConclusion29th
March 201122James BiggsTo realise nano-spacecraft as viable
platforms for remote sensing precise attitude control is
essential.
Poses research challenges low-computational methods for
generating low-cost (zero fuel) motions.
The presented method reduces the kinematics to a subset of
feasible motions that can be defined analytically.
Massive reduction in computation reduced to parameter
optimization.
Can be extended to minimum time problems, three axis re-pointing
i.e. No spinning constraint.
Introduction
Motion Planning
Reduction method
Practicalcost function
Example
Conclusion
Use an arrow like this to mark current sectionThank You for your
attentionQuestions?23