Unknown Input Observer for control design: a bond graph approach

The objective of this paper is the development of a bond graph approach for the control of linear systems subject to unknown inputs (disturbances or failures) with a new unknown input observer. At the analysis step, a causal approach is proposed and intrinsic solvability conditions which do not require the knowledge of the value of parameters are given. The synthesis of the estimator is proposed with formal calculus. A DC motor example is studied with a flatness based control with the estimation of an unknown load.