Sampled output observer design for a class of nonlinear systems

This paper presents a continuous-discrete time observer for a class of uncertain nonlinear systems with non uniformly sampled measurements. Two features of the proposed observer are worth to be pointed out. The first one consists in the simplicity of its calibration, while the second one lies in its comprehensive convergence analysis. More specifically, it is shown that the observation error lies in a ball centered at the origin and whose radius is proportional to the bounds of the uncertainties and the sampling partition diameter. In the free uncertainties case, the exponential convergence to zero of the observation error is established under a well-defined condition on the maximum value of the sampling partition diameter. The effectiveness of the proposed observer is emphasized throughout simulation results involving the estimation of the reaction rate in a typical bioreactor.