Research on stability analysis for non-linear control system with time-delay and parameter-perturbation

In some industrial process control systems with time delay, the delay-time is constantly changing due to various reasons (eg. the variation of pneumatic pressure). Thus the delay-time is a bounded perturbation parameter in the system. Such industrial process control systems are a kind of non-linear control systems with bounded parameter-perturbation. Reference [1~4] put forward a new stability criterion for non-linear time-invariant systems. The idea of the new criterion is to find out the numerical solutions for the control systems by means of digital computer. As a matter of fact, it is a stability criterion based on numerical solutions. In this paper, this new criterion is extended to stability analysis for non-linear time-variant systems with bounded parameter-perturbation. Satisfying control performance is achieved.