Repetitive Control based Disturbance Observer for Uncertain Communication Delays

In control systems, uncertain delays are unavoidable in communication channels. Further, the requirement to track and reject periodic signals has many applications in engineering. However, in most cases disturbances to be compensated are not just periodic but can also be aperiodic. This paper presents a novel Repetitive controller based disturbance observer (RCDOB) to reject both periodic and aperiodic disturbances while being able to track periodic signals in systems with uncertain communication delays.