Model description:
Consider the VTOL example. The following shortcuts ${\rm c}(\cdot)=\cos(\cdot),\quad {\rm s}(\cdot)=\sin(\cdot)$ are used. The $\Delta_0$ is given as
$$\begin{align*} \omega_{0}^{1} &: {\mathrm d}x-v_{x}{\mathrm d}t \\ \omega_{0}^{2} &: {\mathrm d}v_{x}-(u^{2}\epsilon {\mathrm c}(\theta)-u^{1}{\mathrm s}(\theta)){\mathrm d}t \\ \omega_{0}^{3} &: {\mathrm d}z-v_{z}{\mathrm d}t \\ \omega_{0}^{4} &: {\mathrm d}v_{z}-(u^{1}{\mathrm c}(\theta)+u^{2}\epsilon {\mathrm s}(\theta)-1){\mathrm d}t \\ \omega_{0}^{5} &: {\mathrm d}\theta-\omega {\mathrm d}t \\ \omega_{0}^{6} &: {\mathrm d}\omega-u^{2}{\mathrm d}t, \end{align*}$$
where $\epsilon$ is a constant parameter. It can be shown that $\Delta_{0,\mathrm{d}t}^{\perp} = \mathrm{span}\{\delta_{u^1},\delta_{u^2}\}$. Construct $\Delta_1 \in \Delta_0$ such that $v_0(\Delta_1)\in \Delta_1$ holds with $v_0=\Delta_{0,{\mathrm d}t}^{\perp}$, i.e. $\Delta_1$ is given as:
$\begin{align*} \omega_{1}^{1} &: {\mathrm d}x-v_{x}{\mathrm d}t \\ \omega_{1}^{2} &: {\mathrm c}(\theta){\mathrm d}v_{x}+{\mathrm s}(\theta){\mathrm d}v_{z}-\epsilon {\mathrm d}\omega+{\mathrm s}(\theta){\mathrm d}t \\ \omega_{1}^{3} &: {\mathrm d}z-v_{z}{\mathrm d}t \\ \omega_{1}^{4} &: {\mathrm d}\theta-\omega {\mathrm d}t \end{align*}$
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Publication details:
| Title | On calculating flat outputs for Pfaffian systems by a reduction procedure - Demonstrated by means of the VTOL example |
| Publication Type | Conference Paper |
| Year of Publication | 2011 |
| Authors | Schoberl, M., and Schlacher K. |
| Conference Name | 9th IEEE International Conference on Control and Automation (ICCA), 2011 |
| Date Published | 12/2011 |
| Publisher | IEEE |
| Conference Location | Santiago |
| ISBN Number | 978-1-4577-1475-7 |
| Accession Number | 12496118 |
| Keywords | aircraft control, machinery, partial differential equations, sequences |
| Abstract | This paper addresses the problem of generating a flat system parametrization for Pfaffian systems in a constructive manner. The main idea behind the procedure is a subsequent application of transformations that decompose a given Pfaffian system into a sequence of systems. This splitting of a Pfaffian system possesses the property that a parametrization of the bottom part can be elementarily obtained provided a rank criterion is met and the parametrization for the upper part is known. Then (if possible) this procedure will be repeated with the upper system to generate a sequence of systems by gradual reduction of the complexity of the problem. The application of the whole machinery to the VTOL example will demonstrate the effectiveness of the procedure. In fact the well known flat output for the VTOL and an alternative one are derived using this constructive machinery in a systematic fashion. |
| DOI | 10.1109/ICCA.2011.6137922 |
