Partial Lyapunov Strictification: Smooth Angular Velocity Observers for Attitude Tracking Control

2015 ◽  
Vol 38 (3) ◽  
pp. 442-451 ◽  
Author(s):  
Maruthi R. Akella ◽  
Divya Thakur ◽  
Frédéric Mazenc
Keyword(s):  
Angular Velocity ◽  
Tracking Control ◽  
Attitude Tracking ◽  
Attitude Tracking Control

Velocity-free attitude tracking for rigid spacecraft via bounded control

2021 ◽  
pp. 095441002110423
Author(s):  
Jian Zhang ◽  
Wen-Jie Wu ◽  
Long Liu ◽  
Dai Liu
Keyword(s):  
Angular Velocity ◽  
Tracking Control ◽  
Input Saturation ◽  
Control Law ◽  
Input Constraints ◽  
Bounded Control ◽  
External Disturbances ◽  
Attitude Tracking ◽  
Rigid Spacecraft ◽  
Attitude Tracking Control

This article investigates the attitude tracking control problem for a rigid spacecraft without angular velocity feedback, in which external disturbances, parametric uncertainties, and input saturation are considered. Initially, an angular velocity observer is developed incorporated with adaptive technique, which could tackle the unmeasurable angular velocity and system uncertainties simultaneously. By introducing adaptive updating law into the proposed observer, the synchronized uncertainties are handled such that robustness of the observer is enhanced, even in the presence of external disturbances. Further, for solving the input constraints problem, command filter and backstepping method are utilized; thus, a bounded attitude tracking control law is derived. Finally, the attitude tracking performance is evaluated by numerical examples.

Robust backstepping attitude tracking control of an underactuated spacecraft with saturation and time-variant perturbations

2021 ◽  
pp. 095441002110159
Author(s):  
Reza Nadafi ◽  
Mansour Kabganian
Keyword(s):  
Angular Velocity ◽  
Tracking Control ◽  
Initial Conditions ◽  
Large Angle ◽  
Closed Loop System ◽  
External Disturbances ◽  
Asymptotic Stable ◽  
Attitude Tracking ◽  
Attitude Tracking Control ◽  
Invariance Theorem

This study investigated associations of attitude tracking control of an underactuated spacecraft with consideration of saturation and perturbations. A nonsingular attitude tracking control was proposed which did not need limiting initial conditions of the quaternions. The controller was analyzed based on Lyapunov criteria and LaSalle’s invariance theorem in the large-angle maneuver. In order to control, the complete kinematic and dynamic model of the underactuated spacecraft was reconstructed. According to simulation results, our controller has excellent robustness against the hard saturation, external disturbances, time-varying inertia uncertainties, and internal disturbances of actuators. As result, we found that the attitude controller was asymptotically stable under the soft saturation and the perturbations so that quaternions and angular velocity converged to the desired path within the 80 s. Also, it was still asymptotic stable under the hard saturation whose level is equal to 0.035 Nm, 3.5% of the soft saturation level. In this case, errors of quaternions and angular velocity were converged to the origin within the 150 s. Finally, the closed-loop system was verified by Adams-MATLAB co-simulation. The maximum verification errors for quaternions were less than 19%, while the maximum verification errors for angular velocity were less than 13.5%.

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