I. Introduction
In control engineering, the study of coupled systems has been a popular subject in recent years, which has rich physical backgrounds such as coupled mechanical, coupled chemical reactions. Meanwhile, one could point to its many applications in fluid dynamics, plasma system, and other engineering problems [1]. Thus, the stability issue of coupled system is significant both theoretically and practically. Recently, some works have been addressed on control design of cascaded PDE-ODE systems through making use of decoupling and PDE backstepping method such as in [2]-[5].