J. Roshanian; S. M. M. Hassani; M. M. Nazari; M. Aliyari
Volume 6, Issue 2 , July 2013, , Pages 49-56
Abstract
Aerospace Launch Vehicles (ALV) are generally designed with high reliability to operate in complete security through fault avoidance practices. However, in spite of fault avoidance, fault occurring is inevitable. Hence there is a requirement for on-board fault detection and isolation (FDI) without significant ...
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Aerospace Launch Vehicles (ALV) are generally designed with high reliability to operate in complete security through fault avoidance practices. However, in spite of fault avoidance, fault occurring is inevitable. Hence there is a requirement for on-board fault detection and isolation (FDI) without significant degradation in the ALV performance. The robust observers are widely used in FDI due to reduction of the effect of disturbances in the FDI process. In this paper, the robust fault diagnosis observer is designed for an ALV subject to uncertainties. The linear sliding mode technique is used to design the observer for a linear time varying model of an ALV. The parameter estimation from the sliding mode scheme is compared with those generated by a nonlinear simulation and are found to provide good correlation. Then, a proposed linear sliding mode observer is employed to generate the residual as an indicator of predefined gyroscope faults.
Jafar Roshanian; Mehdi Hassani; Shabnam Yazdan; Masoud Ebrahimi
Volume 5, Issue 4 , January 2013, , Pages 1-8
Abstract
Star tracker is an attitude determination device which determines the satellite or spacecraft’s attitude using the star position information in inertial and body references. Star information is collected and stored onboard as a “Star or mission catalog”. There are several star catalogs ...
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Star tracker is an attitude determination device which determines the satellite or spacecraft’s attitude using the star position information in inertial and body references. Star information is collected and stored onboard as a “Star or mission catalog”. There are several star catalogs that contain different kinds of information with different accuracy. In this paper the most used star catalogs are introduced and a few star catalog selection features are recommended. These features are weighted according to the star tracker mission type. For the selected star tracker mission, results demonstrate that Hipparcos star catalog is the best choice. Eventually using Hipparcos star catalog, a mission catalog is developed to be used onboard a typical star tracker.
