Distributed output-feedback observer-less consensus control of nonholonomic systems over networks with communication delays


Nonholonomic systems cannot be asymptotically stabilized to a point via smooth time-invariant feedback. This is due to a structural obstruction than cannot be overcome via feedback. In this talk, we will present the so-called delta-persistently-exciting controllers. They rely on a time-varying function that excites the system's modes while the stabilization error persists and vanishes with the error trajectories, uniformly and asymptotically. Then, we address the formation consensus problem for swarms of nonholonomic systems. Consensus formation is inherently a set-point stabilization problem since it consists in the robots acquiring a formation fixed on the plane at a set-point that is not specified a priori. The consensus-formation problem inherits the difficulties of set-point stabilization and consensus control. The controllers are distributed since, for each robot, they depend on local coordinates and measurements received from close-by neighbours. It is assumed, however, that the robots do not possess velocity sensors and communicate over a wifi network. The latter induces time-varying delays. The controllers are delta-persistently-exciting and they rely on passive filters whose outputs are used in place of the unavailable velocities. These filters, however, are not state estimators. Thus, at least in the present context of output-feedback control, our results obviate the need for distributed state estimation.

*[Work carried out in collaboration with E. Nuño and E. Panteley]


Antonio Loria was born in Mexico City in 1969. He got the BSc degree in Electronic Engineering from the ITESM, Monterrey, Mexico in 1991, the MSc and PhD degrees in Control Engg. from the UTC, France in 1993 and Nov. 1996 respectively. From December 1996 through Dec. 1998, he was successively an associate researcher at Univ. of Twente, The Netherlands; NTNU, Norway and the CCEC of the Univ. of California at Sta Barbara, USA. A. Loria has the honour of occupying a research position as Senior Researcher at the French National Centre of Scientific Research (CNRS). His research interests include control systems theory (adaptive, output feedback, discrete-time, continuous-time, linear, non-linear, hybrid, robust, passive, etc.), dynamical systems theory (stability, chaos) and a variety of applications of the latter, including Lagrangian systems. He has served as an associate editor for Systems and Control Letters, Automatica, IEEE Transactions on Automatic Control, IEEE Transactions on Control Systems Technology, Control Systems Letters, Control Systems Magazine and as a member of the IEEE CSS Conference Editorial Board, and diverse IPCs. Some of his publications are available at https://www.l2s.centralesupelec.fr/u/loria-antonio/