Observer design using a time scaled block triangular observer form

This paper presents an observer design for unforced nonlinear multi-output systems using a time scaled block triangular observer form (TBTOF). The TBTOF generalizes an established block triangular observer Form (BTOF) to include a time scaling function. Such a generalization broadens the class of systems to which a BTOF-based observer design can be applied. A TBTOF-based observer design proceeds subsystem-at-a-time starting with the uppermost subsystem. Designs for each subsystem effectively treat upper subsystem states as known measurements and are relatively simple given their reduced dimension. A necessary condition for the time scaling function is provided. Global uniform asymptotic and exponential observer estimate error stability results are given. These results provide a formula for the observer gain. An example illustrates the construction of a TBTOF and a typical observer design with simulation