Nyquist Stability Criterion for a Class of Spatially Periodic Systems

摘要

The Nyquist stability criterion is extended to a class of spatially periodic systems with spatially distributed inputs and outputs. It is demonstrated that the exponential stability of this class of systems can be guaranteed by checking the Nyquist stability criterion for a family of finite- dimensional systems. In order to show this result, a new version of the argument principle is derived that is applicable to systems with infinite- dimensional input/output spaces and unbounded system operators.