Observer-based Similarity Output Feedback Control of Cyber-Physical Systems*

In this paper, we deal with output feedback embedded control of a cyber-physical system. Both a plant and a controller are modeled by state transition systems. But, the former is infinite while the latter is finite. So, an abstraction of the plant model is used in the design of the controller. We propose an abstracted observer that computes a set of all possible abstracted states using the sequence of injected control inputs and observed outputs of the plant. It is shown that there is a simulation relation from the observer to the abstracted plant model. Using the observer, we construct a similarity output feedback controller for a given transition system representing desired behaviors of the abstracted plant model. It is shown using an approximate alternating relation that the controlled plant exhibits desired abstracted behaviors.