Brief paper - Improved zonotopic method to set membership identification for systems with time-varying parameters

This study proposes an improved zonotopic method to set membership identification for linear discrete-time systems with a bounded description of noise and parameter expansion. As in the previous method, the time-varying nature of parameters is taken into account in a non-conservative way by a zonotope. A new family of zonotopes containing the intersection of a zonotope with a strip is constructed in the observation update procedure. The minimal volume zonotope in this family is selected as the outer bound of the feasible solution set of parameters. It can be proven that this minimal volume zonotope is not larger than the one obtained by means of the previous method. Simulation experiments are conducted showing the performance of the improved method as compared to the previous method and the parallelotopic method. Two types of distribution of the parameter expansion are considered. The results expose the weakness of the previous method and illustrate the effectiveness of the improvement.