Development of common observer schemes using sliding mode observers for robust state estimation and fault detection

The common observer simultaneously estimates the states of one system out of several possible systems without knowing the one being monitored. This thesis presents several developments of common observer schemes for systems with unknown inputs using multiple state observers in cascaded with logic switches. The existence conditions of the schemes are investigated in terms of the original system matrices. These conditions enable the users to know at the outset if the schemes are applicable and show that each state observer can be designed independently in which the design process is significantly simplified.