This paper deals with the output regulation of nonlinear control systems in order to guarantee desired performances in the presence of plant parameters variations. The proposed control law structure is based on the CRONE control scheme. By introducing the multimodel approach in the closed-loop system, the presented design methodology of the CRONE control guarantee desired transient. Then, the multimodel approach is used to analyze the closed-loop system properties and to get explicit expressions for evaluation of the controller parameters. The tuning of the controller parameters is based on a constrained optimization algorithm. Simulation example is presented to show the effectiveness of the proposed method.