We propose a simple control design allowing a mobile robot equipped with a camera to track a line on the ground. The control algorithm, as well as the image-processing algorithm, are very simple. We discuss the existence and the practical stability of an equilibrium trajectory of the robot when tracking a circular reference line. We then give a complementary analysis for arbitrary reference lines with bounded curvature. Experimental results confirm the theoretical analysis.

The structure of the kinematic and dynamic models of wheeled mobile robots is analyzed. It is shown that, for a large class of possible configurations, they can be classified into five types, characterized by generic structures of the model equations. For each type of model the following questions are addressed: (ir)reducibility and (non)holonomy, mobility and controllability, configuration of the motorization, and feedback equivalence.

A hybrid strategy for the control of nonholonomic mobile robots is proposed and assessed, using both theoretical arguments and simulation experiments. The control law is a discontinuous state feedback that combines the advantages of time-invariant smooth feedback control far from the target and of time-varying smooth feedback control close to the target, while avoiding their respective drawbacks.>

Smooth time-varying laws can solve the stabilization problem of nonholonomic mechanical systems. The authors show that by means of dynamic state feedback, it is possible for three-wheeled mobile robots to track arbitrary fast trajectories not reduced to equilibrium points. Dynamical modeling of nonholonomic mechanical systems for the case of three-wheeled mobile robots is considered. Dynamic feedback allows solution of the tracking problem for an omnidirectional mobile robot with less motors than degrees of freedom. This is possible by choosing output functions depending on the mass repartition of the robot.>

An original procedure for the estimation of the barycentric parameters of a robot is presented. This procedure requires only the processing of measurements provided by an external experimental set-up (reactions at the bedplate, and position, velocities, and accelerations). The procedure is based on the property that the relations between the robot motion and its reactions on its bedplate are completely independent of the internal joint forces. Some identifiability issues are discussed, and a validation experiment is reported.>

A general dynamical model is derived for three-wheel mobile robots with nonholonomic constraints by using a Lagrange formulation and differential geometry. It is shown that a static state feedback allows one to reduce the dynamics of the system to a form in which stabilizing input-output linearizing control is possible.>