A systematic method for the analysis and design of multirate control systems

Due to the advances in digital computers and microprocessors, a great deal of effort has been put into research in digital control systems. In order to efficiently utilize the computational capacity of the onboard computer and accommodate various sensors information available at multiple rates, multirate sampling techniques are applied to control the systems. Although multirate sampling plays an important role in the aerospace and navigation fields, most of the work in the past has involved single-rate systems where all sampling rates are the same.;The design approach is done by the application of a robust controller in multirate systems. The robust controller design for multirate plants is formulated as a discrete H;A systematic approach to the analysis and design of multirate systems is developed in this work. The analytical approach consists of two stages. The first one is the application of the state transition method to obtain the open-loop or closed-loop response of the system. To avoid the tedious derivation of the state transition equation of the system, a time chart that represents the transitions of the system is proposed. It provides a direct way to write the state transition equation by observation. The second stage utilizes a simplified method to determine the loop transfer function of the system. Some properties that relate to the simplified method are stated in lemma form. The proof of these lemmas are included. The applications of the systematic analysis method for single-loop and multiloop multirate systems are illustrated through example systems. Their results and the comparisons with other techniques are also provided.