“…This methodology is found in a great variety of model-settings, e.g., from single non-linear systems [8] towards multi-agent, possibly large scale, systems [19,5,6]. A more integral approach for detection and isolation of faults is an unknowninput type estimator, which decouples the effect of unknown state measurements and disturbances (or faults) from the residual through an algebraic approach [16,9] or approaches using the generalized inverse [1,27]. Multiplicative faults are inherently more difficult to detect and isolate due to their non-linear appearance in the model, hence, it requires non-linear approaches, e.g., adaptive-type observers [23] or sliding-mode observers [21].…”