Design of Parity Equations Using Right Eigenstructure Assignment

System uncertainties, such as modelling errors, external disturbances etc. can impede the fault detection process. Therefore a need arises for robust fault diagnosis, where complete disturbance decoupling can be achieved. The main contribution of this paper is the design of a parity relation for robust fault detection using right eigenstructure assignment. Up to date the left eigenstructure assignment technique has been used for the design of first order disturbance decoupled parity relations. In many cases complete disturbance decoupling is not possible when using left eigenstructure assignment. Therefore, the proposed method utilises the right eigenstructure assignment technique for the purpose of robust fault detection. The novelty of the developed scheme is to replace the traditional asymptotically convergent state observer by a state observer, which converges in a predefined time. The proposed method is demonstrated to be equivalent to a parity relation of a user predefined order.