Some results about nonlinear regularly persistent observers

Some recent results about nonlinear regularly persistent observers applied to some class of nonlinear systems are presented. The authors propose an observer based on a Kalman-like observer, which is formed with a copy of the model of the system plus a corrective term K(t). This term is being computed by minimizing some criterion depending on the output error. Following this criterion, an observer is obtained which works for a class of admissible inputs