This paper introduces a straightforward view of constructing controllers for linear systems directly from the system model and the desired step response of the closed-loop system. When this approach is applied to any scalar state variable, the result is an elementary linear controller formally, but composed of two discrete parts. The 'trajectory control' part realizes a first- or second-order low-pass filter on the command value. The 'error compensation' part corrects the controller's operating point in the manner of a first-order high-pass filter on the current model error. This controller is stable by design and oscillation-free, its step response without overshooting, for any possible parameterization. The utility of above approach is demonstrated on helicopter flight control, as very successfully used in the field with the MARVIN helicopter UAV. Much opposed to statements frequently found in the literature, helicopter dynamics are in fact fully linear with very small error. The MARVIN control architecture performs smooth 3D multi-point trajectory flight with nothing but linear elementary controllers, purely due to a clever choice of the controlled variables. It is true that the sequential ordering of multiple trajectory control, coordinate transformation and error compensation blocks constitutes an idelalization to some degree. On the other hand, in 'classical' monolithic system modeling, more explicit simplifications of the dynamics or even of the kinematics are quite often incorporated in order to obtain a monolithic system model that can actually be handled. In these cases, the accuracy of the dynamics model will also be affected, its suitability possibly restricted to a certain operating area, and all these simplicications obscured within the model. This and the good performance in real applications support the presented approach against concerns regarding its idealizations.
Model-interleaved, stable-by-design construction of controllers exemplified with helicopter flight control
Modellverzahnte, widerstandsfähige Reglerkonstruktion, veranschaulicht durch Helikopter-Flugregelung
2006
27 Seiten, 19 Bilder, 13 Quellen
Report
English
Design of Intelligent Flight Controllers for Helicopter Control
British Library Conference Proceedings | 1997
|Implicit and Explicit Model-Following Helicopter Flight Controllers
British Library Conference Proceedings | 1994
|Model helicopter flight control
Tema Archive | 2009
|Model Helicopter Flight Control
British Library Conference Proceedings | 2009
|