Comparative study of various control methods for attitude control of a LEO satellite

1999 ◽  
Vol 3 (5) ◽  
pp. 323-333 ◽  
Author(s):  
Chang-Hee Won
2018 ◽  
Vol 41 (5) ◽  
pp. 1189-1206 ◽  
Author(s):  
M Kemal Ozgoren

This paper presents a comparative study about the attitude control methods based on four commonly used error indicators, namely the triad of 3-2-1 deviational Euler angles, the error quaternion, the deviational angle–axis pair and the orientation error matrix. These error indicators are used here with the same backstepping control law to have a common basis of comparison. This control law makes the controller track a restoring angular velocity generated here specifically for each error indicator. This comparative study shows that all these error indicators can be used satisfactorily even in the critical orientations associated with them by taking special measures. For the deviational Euler angle triad, a critical orientation is a singularity, at which the angles become indefinite. Unless the vehicle is stationary, this indefiniteness is resolved here by applying L’Hopital’s Rule on the angular velocity information. The Euler angle triad has also a multiplicity problem. It is solved here by using the novel criterion of minimal deviation angles. For the other error indicators, a critical orientation is an antipodal orientation, which is opposite to the desired one. In an antipodal orientation, the error quaternion and the deviational angle–axis pair cannot be determined through the customary formulas. They are determined here by using the novel specially introduced formulas. Besides, they may suffer from the unwinding phenomenon in an ordinary orientation. This phenomenon is prevented here by keeping the scalar part of the error quaternion non-negative and the deviation angle between 0° and 180°. For the orientation error matrix, a stationary and undisturbed antipodal orientation is an unstable equilibrium, in which the ordinary backstepping control law becomes ineffective for driving the system into action. This problem is solved here by adding an extra term to the ordinary backstepping control law.


Author(s):  
Jameson Y. Lee ◽  
Zachary Cook ◽  
Alexander Barzilov ◽  
Woosoon Yim

Multirotor Unmanned Aerial Systems (UAS) are highly mobile in flight and possess stable hovering capabilities. Because of their unique flight characteristics, the utilization of the platform for active tasks such as aerial manipulation is highly attractive. Much work has been done in recent years towards the implementation of multirotor for aerial manipulation, however, progress in the field has been slow due to the many challenges involved in the implementation of robust rotor control. In an attempt to reduce the effects of the manipulator, a technique for disturbance rejection using a novel balancing mechanism is proposed. In this paper, the dynamic equations of a coupled multirotor and manipulator are analyzed as a single body for use in the attitude control of the platform. By mounting the mechanism, the platform effectively gains marginal control over the positioning of its center of gravity relative to a body fixed frame. It can be shown that the increased mobility can be utilized to reduce rotor saturation for any given flight condition and improve the effectiveness of previously developed rotor control methods.


2020 ◽  
Vol 104 ◽  
pp. 102142
Author(s):  
Luís Miguel Martins ◽  
Nuno Octávio Garcia Fernandes ◽  
Maria Leonilde Rocha Varela ◽  
Luís Miguel Silva Dias ◽  
Guilherme Augusto Borges Pereira ◽  
...  

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