Poster Session

Felix Kong, Contraction Analysis of Iterative Learning Control

Iterative learning control (ILC) is widely used as a simple method for precise tracking of systems under repetitive conditions. ILC operate by “learning” from the previous iteration’s errors, correcting them over a number of iterations. However, the question of whether or not a nonlinear ILC system converges is still in general an open one. Assuming a state- space formulation, we use contraction analysis to formulate a convergence condition for ILC as a linear matrix inequality (LMI).

Julien Monteil, On the design of nonlinear control protocols for stable platooning systems

We are concerned with the problem of designing stable platooning systems of automated vehicles. We present a set of sufficient conditions for the stability of acyclic directed networks. We show how this can be applied to the design of linear and nonlinear distributed control protocols for vehicle platooning.

Sérgio Waitman, A piecewise-affine approach to nonlinear performance

The use of the incremental L2-gain has been proposed as an extension of the weighted H∞ norm approach for LTI systems. However, necessary and sufficient conditions for incremental L2-gain stability remain difficult to verify in the general case, and existing techniques are based on relaxations that may introduce too much conservatism. In this work, we propose a new approach based on piecewise-affine representations of nonlinear systems. This allows us to reduce the conservatism while proposing efficient methods based on convex optimization.

Vincent Andrieu, Some results on exponential synchronization

Based on recent works on transverse exponential stability, we establish some necessary and sufficient conditions for the existence of a (locally) exponential synchronizing control law. We show that the existence of a structured synchronizer is equivalent to the existence of a stabilizer for the individual linearized systems (on the synchronization manifold) by a linear state feedback. This, in turn, is also equivalent to the existence of a symmetric covariant tensor field, which satisfies a Control Matrix Function inequality. Based on this result, we provide the construction of such synchronizer via backstepping approaches. In some particular cases, we show how global exponential synchronization may be obtained.