Mobile robots are nowadays used in a wide variety of missions especially for exploring environments and allowing scientists who study these environments to gather data about them. However the monolithic design of control laws is often a hindrance to adapting control solutions from a robotic application to another. We thus propose a new control description paradigm strongly focused on modularity as well as integrating constraints coming both from the system capabilities and from the concerns of control engineering (such as stability). In this paper, we present the main ideas behind our approach and illustrate it through Hardware-In-the-Loop simulation.

This paper addresses the problem of coordinated path tracking for networked nonholonomic mobile vehicles, while building and keeping a desired formation. The control laws proposed are categorized into two envelopes by integrating individual path tracking and global virtual structure approaches. One is steering individual vehicles to track virtual vehicles moving along predefined paths, generated by a formation reference vehicle (FRV) of a time-varying desired virtual structure. The other is ensuring paths to be well tracked in order to build a geometric formation, through the distributed feedback law for path parameters related to the virtual vehicles, such that the physical vehicles are on the desired placements of the formation structure. Within this framework, geometric path tracking is achieved via nonlinear control theory, where an approaching angle is injected as a heading guidance design. The distributed feedback law is analyzed under communication constraints using algebraic graph theory. It is formally shown that the path tracking error of each vehicle is reduced to zero, and vehicles in the networked team globally asymptotically converge to a desired formation with equal path parameters. Simulation results illustrate the effectiveness of the proposed control design.

This paper proposes a novel control strategy for autonomous underwater vehicles (AUVs), named as path tracking, which combines the conventional path following and trajectory tracking control in order to achieve smooth spatial convergence and tight temporal performance as well. This idea is inspired by the previous work of Hindman [1] and Encarnacao [2], however, the path tracking design herein goes from path following to trajectory tracking, which indeed is an inverse way from the previous solutions so that the complex projection algorithm resulting in a local stability is avoided. A kinematics controller is first derived by using Lyapunov direct method where a virtual path parameter is introduced to bring an extra control degree of freedom, and then it is extended to the dynamics of AUVs based on backstepping technique. The resulting nonlinear control design is formally shown and it yields global asymptotic convergence of the AUV to the path. Finally, simulation results illustrate the efficiency of the path tracking control design for AUVs.

This paper presents a global methodology developed to increase the reliability of mobile robots. An initial analysis of robot functions and their corresponding significant failures enabled us to introduce dedicated observation modules in the embedded architecture to monitor fault events. Once detected, the functioning mode of the robot can be adapted according to the failure severity level to ensure the success of its mission. The methodology was applied in a case study and the experimental implementation and results are detailed.

This paper addresses the problem of simultaneous path following control, obstacle avoidance and collision free for coordinated multiple nonholonomic autonomous vehicles under formation constraints. Global heading guidance design is highlighted in individual path following and augmented for obstacle avoidance between vehicles and obstacles. Within a leader-follower framework, the geometric formation is guaranteed by speed adaptation of individual path following control, and collision free among vehicles is also achieved by trimmed heading guidance. Simulation results illustrate the efficiency of the guidance based control design.

The aim of this paper is to review the available simulators defining in a first step the necessary requirements to cope with the multi-vehicles cooperation context. In order to get a complete overview of these tools, a new classification is proposed and is used to sort the existing simulators. It is worth to be noted that we focus our interest on simulators which can at least address the problem of marine robotics.

This paper addresses the problem of coordinated path following of multiple wheeled mobile robots while keeping a desired formation. The control laws proposed are categorized into two envelopes, one is steering individual robots to trace along predefined paths, and the other is ensuring tracked paths to be well defined in the formation, by means of decentralized speed adaption.Within this framework, geometric paths following are built on Lyapunov theory and backstepping techniques, while injecting helmsman like behavior into individual path following control. Speed adaption with minimum communication variable under the constraints of multi-robot communication topology, is elaborately designed without relative speeds between neighboring robots requested. The simple but effective controller design, enables multi-robot system to be coordinated and stabilized into an invariant manifold, and all speeds converge to desired profiles in addition. Simulation results illustrate the efficacy of the solution proposed.

This paper proposes an algorithm that drives a unicycle type robot to a desired path, including obstacle avoidance capabilities. The path following control design relies on Lyapunov theory, backstepping techniques and deals explicitly with vehicle dynamics. Furthermore, it overcomes initial condition constraint present in a number of path following control strategies described in the literature. This is done by controlling explicitly the rate of progression of a "virtual target" to be tracked along the path; thus bypassing the problems that arise when the position of the path target point is simply defined as the closest point on the path. The obstacle avoidance part is using the deformable virtual zone principle, that defines a safety zone around the vehicle, in which the presence of an obstacle induces an "intrusion of information" that drives the vehicle reaction. The overall algorithm is combined with a guidance solution that embeds the path following requirements in a desired intrusion information function, that steers the vehicle to the desired path while the DVZ is virtually keeping a minimal contact with the obstacle, implicitly bypassing it. Simulation and experimental results illustrate the performance of the control system proposed.

We present a neural network architecture that belongs to the multilayer perceptron family, associated with two different algorithms: the ordinary gradient and the natural gradient, we compare the performances of those algorithms. The identification of a non-normalized power amplifier yielded to the introduction of an additional weight in the classical multilayer perceptron structure. The application of this network is space telecommunications: identification of satellite communication channels, and especially the down link. This link is made up with two elements. The first one is a high power amplifier (non-linearity). The second one is a filter (memory).