Equivalence of Control Systems with Linear Systems on Lie Groups and Homogeneous Spaces

TL;DR

This paper proves that control affine systems on manifolds are equivalent to linear systems on Lie groups or homogeneous spaces if their vector fields are complete and generate a finite-dimensional Lie algebra, using geometric control theory.

Contribution

It establishes a necessary and sufficient condition for equivalence of control systems to linear systems on Lie groups or homogeneous spaces, extending previous theoretical results.

Findings

Complete vector fields generate finite-dimensional Lie algebras.

Equivalence characterized by diffeomorphisms and flow automorphisms.

Main theorem relates algebraic properties to geometric control system structures.

Abstract

The aim of this paper is to prove that a control affine system on a manifold is equivalent by diffeomorphism to a linear system on a Lie group or a homogeneous space if and only the vector fields of the system are complete and generate a finite dimensional Lie algebra. A vector field on a connected Lie group is linear if its flow is a one parameter group of automorphisms. An affine vector field is obtained by adding a left invariant one. Its projection on a homogeneous space, whenever it exists, is still called affine. Affine vector fields on homogeneous spaces can be characterized by their Lie brackets with the projections of right invariant vector fields. A linear system on a homogeneous space is a system whose drift part is affine and whose controlled part is invariant. The main result is based on a general theorem on finite dimensional algebras generated by complete vector fields, closely related to a theorem of Palais, and which have its own interest. The present proof makes use of geometric control theory arguments.