Input and output coupled nonlinear systems

In this paper, a class of input and output coupled nonlinear systems with multiple equilibria are studied. These kinds of systems can also be viewed as interconnected systems composed of single-input and single-output systems through some linear and nonlinear interconnections. Frequency-domain conditions are established for global convergence and convergence of bounded solutions for such systems. The effects of nonlinear input and output interconnections can be studied through a nonsingular matrix. The design method based on linear matrix inequality for the interconnected matrix is presented. In addition, the relation between input and output coupling here and input transformation in control theory is established. The coupling method is illustrated through a coupled Chuaʹs circuit. The nonexistence of chaotic attractors or limit cycles in the coupled Chuaʹs circuit can be analyzed by convergence of bounded solutions.