A Stable Interval Observer for LTI Systems with No Multiple Poles

The design of interval observers with proven stability for LTI systems was often subject to additional assumptions like monotone influences in the vector field. Recently, such restrictions have been overcome by using a time-varying change of variable. In this paper, a stable interval observer for stable (or observable) LTI systems with no multiple poles is proposed by using different mathematical tools and unified notations. Based on complex numbers, they provide an alternative understanding of the problem of designing stable interval observers. The results are applied to the verified model-based design of a vehicle suspension with an oscillatory behavior and bounded inputs modeling an uncertain road profile.