A New Causal Ideal Internal Dynamics Generator
  The design of ideal internal dynamics (IID) generators, namely solving IID, is a fundamental problem, which is a key step to handle the nonminimum-phase output tracking problem. In this paper, for a class of unstable matrix differential equations, a new causal dynamic IID generator is proposed, whose parameters are partly chosen via H_2/H_inf optimization. Compared with existing similar generators, it is applicable to matrix differential equations with singular system matrices and is easily extended to slowly time-varying matrix differential equations without extra computation. 
Quan Quan and Kai-Yuan Cai
cs.SY