Reducing the Effects of Inaccurate Fault Estimation in Spacecraft Stabilization

Autor: Rouzbeh Moradi, Alireza Alikhani, Mohsen Fathi Jegarkandi
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Journal of Aerospace Technology and Management, Vol 9, Iss 4 (2017)
Druh dokumentu: article
ISSN: 2175-9146
Popis: Reference Governor is an important component of Active Fault Tolerant Control. One of the main reasons for using Reference Governor is to adjust/modify the reference trajectories to maintain the stability of the post-fault system, especially when a series of actuator faults occur and the faulty system can not retain the pre-fault performance. Fault estimation error and delay are important properties of Fault Detection and Diagnosis and have destructive effects on the performance of the Active Fault Tolerant Control. It is shown that, if the fault estimation provided by the Fault Detection and Diagnosis (initial “fault estimation”) is assumed to be precise (an ideal assumption), the controller may not show an acceptable performance. Then, it is shown that, if the worst “fault estimation” is considered, it will be possible to reduce the effects of fault estimation error and delay and to preserve the performance of the controller. To reduce the effects of this conservative assumption (worst “fault estimation”), a quadratic cost function is defined and optimized. One of the advantages of this method is that it gives the designer an option to select a less sophisticated Fault Detection and Diagnosis for the mission. The angular velocity stabilization of a spacecraft subjected to multiple actuator faults is considered as a case study.
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