One of the emerging topics in the realm of distributed space systems is cluster flight of nanosatellites. As opposed to formation flight, cluster flight does not dictate strict limits on the geometry of the cluster, and is hence more suitable for implementation in nanosatellites, which usually do not carry highly accurate sensors and actuators. The actuators are usually simple fixed-magnitude thrusters, which are prone to many sources of errors, such as attitude determination and control errors. In this context, the purpose of this paper is to develop a cluster-keeping control law that is capable of long-term operation under thrust uncertainties, assuming fixed-magnitude thrust provided by a simple cold-gas thruster. To that end, mean orbital elements are used for designing an inverse-dynamics controller. It is shown that, in the differential mean elements space, this controller is time-optimal. An adaptive enhancement is developed to mitigate the thrust pointing errors and restore the original optimal performance, thus saving much fuel. Several simulations and comparative studies are performed to validate the analytical results.
All Science Journal Classification (ASJC) codes
- Control and Systems Engineering
- Aerospace Engineering
- Space and Planetary Science
- Electrical and Electronic Engineering
- Applied Mathematics