Performance of periodically time-varying controllers for sampled data control

This paper analyzes performance of periodically time-varying sampled data controllers for [L.sub.p] deterministic and uniform disturbance rejection. For a given linear periodic sampled data controller controlling a linear time-invariant continuous-time plant, it is shown that a linear time-invariant controller can be found to give better [L.sub.p] sampled data control than the time-varying controller. The performance analysis is in time domain using convexity properties of the [L.sub.p] signal space. Index Terms - Continuous-time systems, discrete-time systems, [L.sub.p] control, sampled data control, time-varying systems.