Observer design for a class of disturbed nonlinear systems with multirate sampled outputs involving multiple long time-varying delays

The design of a high gain observer is proposed for a class of Multi-Input/Multi-Output uniformly observable systems where each output measurements may be available under the form of samples with a long time-varying delay. The sampling partitions associated to the outputs as well as the underling output delays may be different. For clarity purposes, the proposed design is first presented in the case where all the output measurements are available under the same partition and the same long time-varying delay before being extended to the case of multirate sampling with multiple output delays. Simulation results dealing with a flexible joint robot arm are given for illustration purposes.