Robust Adaptive Output Feedback Control of MIMO Systems Using Multirate Sampling

In adaptive output feedback control based on almost strictly positive real (ASPR) conditions, a technical difficulty arises when the controlled multi-input multi-output (MIMO) system is non-square. To overcome this, the idea of multirate sampled-data control has been proposed. That is, through careful choice of faster input sampling rates create a lifted discrete-time system which has the same number of inputs and outputs and does not give rise to the causality constraint. The output feedback based adaptive control strategy can then be applied to this lifted system under certain conditions. In this report, we propose a robust adaptive controller design scheme for non-square MIMO systems using the multirate sampling strategy without the causality problem