Mixed l2 /l∞ / H∞ estimation for uncertain discrete-time systems

A new criterion of l₂ -l_infin / H_infin performance is established by introducing a slack matrix. The designed estimator possesses two outputs which are respectively used to estimate the different estimated signals with l₂-l_infin and H_infin performances. Conservatism inherent in the quadratic framework can be reduced in robust synthesis of systems with polytopic uncertainties, since the parameter dependent Lyapunov functions can be adopted. A numerical example is included to illustrate the feasibility and advantage of the proposed representations.