Showing 2 results for H. R. Momeni and N. Sadati
M. Jafarboland, H. R. Momeni and N. Sadati,
Volume 21, Issue 2 (1-2003)
Abstract
Various methods are presented to control the attitude of satellite due to lack of information of yaw axis attitude so far.
In this paper, a new method is used which is more general and is applicable to all types of satellites, with at least one controller.
This method is not limited to YAW axis and can control the two other axes as well. One feature of this approach is the ability to be modified for large angle maneuvers for special applications.
A new observer is also proposed for the controller, which causes the angles attitude to be kept in desirable values, with minimum control effort and more accuracy. Simulation results show that compare with methods using the complete all axis information, this approach is satisfactory.
Keywords: Attitude control, PID controlley, BIBO stability, pseudo observer
M. Jafarboland, H. R. Momeni and N. Sadati,
Volume 22, Issue 1 (7-2003)
Abstract
Designing a robust tracking control for a non-linear MIMO system with uncertainty is one of the most complicated control problems. In this paper, sliding mode changed to non-linear controllable canonical form by input-output linearization. This, sliding surfaces can be defined in a way that we can de-couple equations and indicate the sliding conditions of multi-variable controller system. The uncertain parameters will be estimated properly and the input equation improved to apply the restricted input condition. The control law will be improved in a way that in addition to increasing the tracking accuracy inside the boundary layer, the speed of convergence will increase outside of the boundary layer. In order to satisfy the balance of the filter, the thickness of the adaptive boundary layer is used. Thus, a robust tracking control is designed which can trace the angle
of attitude of satellite for maneuvers with a very large angle (180 deg.) on a piece-wise smooth path. Finally, the simulation results are compared with Elmali & Olgac’s methods and it is shown that despite decreasing control signals, the tracking accuracy increases by several ten times.
Keywords: Attitude, Control, Sliding-mode control, Non-linear System, Input-Output Linearzation
