Multi-input control-affine systems static feedback equivalent to a triangular form and their flatness

TL;DR

This paper characterizes control systems with multiple inputs that are equivalent to a triangular form and are flat, providing PDE-based methods to find flat outputs, with applications to mechanical systems like a coin rolling on a moving table.

Contribution

It offers a complete geometric characterization of multi-input control systems equivalent to a triangular form and introduces PDE methods to find flat outputs.

Findings

Control systems with m+1 inputs are classified as flat when equivalent to a triangular form.

A PDE system is provided to compute all flat outputs for these systems.

Application demonstrated on a mechanical system: coin rolling without slipping.

Abstract

In this paper, we give a complete geometric characterization of control systems, with m+1 inputs, locally static feedback equivalent to a triangular form compatible with the chained form, for m=1, respectively with the m-chained form, for m>1. They are x-flat systems. We provide a system of first order PDE's to be solved in order to find all x-flat outputs, for m=1, respectively all minimal x-flat outputs, for m>1. We illustrate our results by examples, in particular by an application to a mechanical system: the coin rolling without slipping on a moving table.