Development and applications of multirate digital control

Multiple sample rate digital control systems are of prominent interest in current control research, development, and applications. Modern aerospace vehicles and systems are described by high-order dynamic models which typically include phenomena covering a wide range of characteristic frequencies and instrumentation measurements available at multiple rates. A multirate control structure allows the designer to accommodate multiple information rates and implement required control computations within the finite computational capabilities of an on-board computer. In this paper the historical development, representative design approaches, and example applications of multirate digital control are outlined. A brief survey of traditional design approaches and techniques currently in development is presented. Potential future areas of research and application of multirate control are suggested and discussed.