Speaker
Mr
Adrian Danciu
(University Politecnica of Bucharest)
Description
The aim of the paper is to present a new design methodology for the automatic flight control system of launch vehicles using discrete-time RST controllers. The structure of such a control system has three degrees of freedom (roll, yaw, pitch), determined such that the closed-loop dynamics of the launch vehicle tracks the output of a desired reference model. The RST control technique focuses on the pitch angle, as the roll and yaw angles are tracking their references much easier.
Although the RST controller operates with input-output discrete time system models (and not with their continuous state representations), integration into a launcher is possible, thanks to continuous-discrete-continuous conversion tools. Thus, the continuous time launcher state space representation of each freedom degree can be first converted into the transfer function (continuous as well). Next, a discretizing technique (such as bilinear) is applied, in order to determine the discrete time transfer function. The RST controller is then designed according to the resulted transfer function and a prescribed second order system, standing for the desired closed-loop behavior. Such a controller is processing the reference trajectory and the actual angle (e.g. pitch) as input signals, to return the necessary command. Finally, the 2 by 1 controller transfer function is converted to the minimal discrete time state space representation, which, on its turn, is brought back to continuous time through some interpolation technique (usually, bilinear as well). The RST design controller relies on the poles placement method and reduces to solving a dyophantine equation in this case, although some other more sophisticated methods could have been considered as well.
The paper is organized as follows: after an introductory part, the second section presents the design models (after linearization) describing the dynamics and kinematics of the launcher, together with the design objectives concerning the control system. The design methodology of the discrete time RST controller is presented in the third section. The theoretical developments are illustrated and analyzed through some numerical examples in section 4. Some concluding remarks and future developments of the proposed approach complete the article.
| Applicant type | Co-author |
|---|
Primary author
Mr
Dan Stefanoiu
(University Politecnica of Bucharest)
Co-authors
Mr
Adrian Danciu
(University Politecnica of Bucharest)
Mr
Adrian-Mihail Stoica
(University Politehnica of Bucharest)
Mr
Alvaro Martinez Barrio
(ESA)
Mr
Cristian Constantinescu
(University Politehnica of Bucharest)
Elena Margareta Cimpoesu
(Universtiy Politehnica of Bucharrest)
