scholarly journals Attitude stabilization of a rotating spacecraft with flexible elements and a magnetohydrodynamic control system

2003 ◽  
Vol 10 (1) ◽  
pp. 25-39 ◽  
Author(s):  
Boris Rabinovich ◽  
Alexey Grishin
Author(s):  
RAJA MUNUSAMY ◽  
Ugur Guven ◽  
Om Prakash

Attitude control system plays the important role for to maintain the satellite to desired orientation. To control the satellite it is necessary to do the attitude stabilization. Attitude stabilization achieved by Star sensor, sun sensor, Earth sensors. Attitude control is mainly used for antenna pointing accuracy, camera focus to earth surface and solar panel pointing toward sun. Due to tumbling effect satellite will rotate all the direction in the space. To maintain the orientation of the satellite it is necessary to design the attitude determination and control. Satellite consider as the rigid body. Inertia matrix describes the rigid body dynamics.  The orientation of the satellite determine by Euler angle and Quaternion. Low earth orbit satellite will have enormous amount of aerodynamic drag stinking the satellite body and gravitational attraction another problem. Because of that satellite dwell time is reduced. It means satellite more time spending particular part of the earth. The attitude estimation is measures by the orientation of vectors. Attitude estimation means to find the position and orientation of flying object with respect to the fixed reference of reference. Vector remains considered in the frame of reference to compute for find the orientation of the body of the satellite in the inertial reference system. Earth is an inertial reference frame, Satellite is a body frame. Attitude sensor used to measure the satellite orientation in the reference frame. This will help in accurately predicting the orbit deviation and a control system to correct if any by providing the satellite momentum means ‘mass in motion’ changes in a body rapidly in Low earth orbit due to centripetal force acting on a satellite. Attitude control system (ACS) need the numerical simulation to find the required torque demand by the help of difference between reference input (Attitude) signal and feedback signal measure by attitude sensor to trim the control surface maintain the actuator required orientation . The results will consist of two parts the first part consisting of the attitude estimation using Euler angle and Quaternion method, second part consist of estimate the control torque from magnetic torquer and error estimation using non-linear filter (Unscented Kalman Filter) with MATLAB simulation.


2016 ◽  
Vol 40 (2) ◽  
pp. 591-605 ◽  
Author(s):  
Babak Baghi ◽  
Mansour Kabganian ◽  
Reza Nadafi ◽  
Ehsan Arabi

In this paper, after complete modelling of a flexible satellite equipped with a control moment gyroscope (CMG) actuator, it is shown that a PD-like controller can globally asymptotically stabilize this satellite by using Lyapunov’s direct method. Despite the simplicity, simulations show that the controller can stabilize the flexible satellite in a three-axis manoeuvre even in the presence of external disturbances. Then, using a non-linear variable gains PD controller, which only uses angular velocity of the rigid body and the attitude parameters as the inputs, the performance of the control system is improved in some important aspects such as reducing maximum control torque, reducing maximum peak of deflection of the appendages and increasing robustness of the controller against the orbital disturbances. In addition, locally asymptotically stability of the non-linear variable gain PD controller is guaranteed using a novel Lyapunov candidate function. Considering the difficulty in measuring the appendages’ deflection and the primarily existence of parameter uncertainties, and as this controller is independent of changes in these parameters, such a control system is very useful and applicable. In order to validate the system’s mathematical model and the control system performance, an exact model of the satellite is constructed in the ADAMS/View software that is linked to the MATLAB software. The efficacy of the proposed approach is demonstrated by several numerical examples.


2020 ◽  
Vol 8 (2) ◽  
pp. 164-170
Author(s):  
Sumardi Sumardi ◽  
Hadha Afrisal ◽  
Wisnu Dyan Nugroho

This research aims to develop a quadrotor control system for maintaining its position and balance from disturbance while hovering. A fast and reliable control technique is required to respond to high maneuverability and high non-linearity of six degrees of freedom system. Hence, this research focuses on designing a Self-Tuning Fuzzy-PD control system for quadrotor’s attitude. The designed control system utilizes input data from the Inertial Navigation System (INS). Then the quadrotor’s attitude is controlled by passing the PWM signal to the flight controller APM 2.6. The result shows that the average absolute error for the roll, pitch, and yaw angles are relatively small, as mentioned consecutively 2.0790, 2.2660, and 1.5280, while the maximum absolute errors are 6.3140, 6.7220, and 3.820.


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