Passive fault tolerant perfect tracking with additive faults

An architecture of a control system with additive faults is given, with a controller consisting of three blocks, and a problem of fault-tolerant (FT) perfect tracking is formulated. It is shown that there is a passive FT controller such that its performance is not worse than the performance of the nominal controller, while in presence of faults, it practically rejects the faults, on expense of a big magnitude of the control in times when faults appear. A numerical simulation is given.