Observability and Nonlinear Observers for Mobile Robot Localization

In this paper, the problem of localizing a nonholonomic vehicle moving in an unstructured environment is addressed by the design of a novel nonlinear observer, based on suitably processed optical information. The localization problem has been shown to be intrinsically nonlinear, indeed the linear approximation of the system has di erent structural properties than the original model. The proposed nonlinear observer allows the localization of nonholonomic mobile robots by using an estimated expression of the extended output Jacobian, local practical stabilization of the observation error dynamics is also ensured. A singularity-avoidance exploration strategy is also included to deal with the output Jacobian singularities crossing.