Stability and stabilization scheme for systems with time delay

This paper describes stability analysis and a stabilizing control design for a system with time delay. A delay often occurs when the transmission path includes a computer network. For a time delay, the stability analysis in the frequency domain approach is not sufficient; thus, stability analysis in the time domain is required and typical method is based on the Lyapunov-Krasovskii functional (LKF). This paper describes stability analysis and the design of stabilizing controllers based on various types of LKFs. The paper also describes a model-based control for a system with time delay and it resolves the issue on the communication disturbance observer (CDOB), which generates steady state error if there exists model error. Results of experiments conducted on a DC motor are shown and they confirmed the validity of the proposed model based control method.