Attitude Control of Asteroid Orbiting Spacecraft
- Paper number
IAC-06-C1.1.03
- Author
Dr. Gianmarco Radice, University of Glasgow, United Kingdom
- Coauthor
Mr. Imran Ali, University of Glasgow, United Kingdom
- Year
2006
- Abstract
The purpose of this paper is to present the results of the attitude control of a spacecraft orbiting a rotating asteroid. The highly irregular static and dynamical properties of a typical asteroid lead to complex and challenging issues for spacecraft attitude dynamics and control. The method proposed here aims to drastically reduce the workload required to control the spacecraft attitude. This method derives from Lyapunov’s Second Method for stability analysis and hinges on the definition of an artificial potential function. The potential function control method represents a means of both estimating the desired states of a spacecraft’s attitude, and autonomously correct and control these states. The advantage of using such an approach is that non-linear commands may be generated, since the method does not hinge on linearisation. At the same time however the method guarantees stable and asymptotic convergence to the final state. In general we have a set of differential equations that characterises in time the evolution of a particular system. Together with the information on this particular dynamical system, provided by the equations of motion, we have also additional information under the form of initial conditions. A variation in these conditions produces a change in the solution of the system. If the system is asymptotically stable however, the solution of the system will always tend towards a known final state. By defining the final state and building a Lyapunov function that has a global minimum in the final state it is possible to obtain an analytical form for the commands that will allow the aforementioned conditions to be met. The commands will guarantee the asymptotic stability of the system and the spacecraft will manoeuvre following an assigned set of differential equations converging to the desired final state.
- Abstract document