Robust inversion-based feedforward controllers for output tracking under plant uncertainty

The article develops acceptance bounds on the size of the uncertainties under which it is advantageous to use the inverse-feedforward for linear, time-invariant systems. In particular, for single-input single-output (SISO) systems, the conditions developed in the article showed that inversion-based feedforward controllers can lead to performance improvements if the uncertainty in the nominal plant is smaller than size of the nominal plant. The results were also generalized to the multi-input multi-output (MIMO) case.