Sum-of-squares observer design for a polynomial system with unknown time delays

The topic of the paper is a procedure for observer design for polynomial systems. The design is based on sum-of-squares through construction of suitable Lyapunov-Krasovskii functionals. As the resulting problem is not convex, an iterative formula is proposed to obtain the solution. Estimates of observation error are derived, the usage of the method is illustrated by an example.