Fast Reference Governors for Systems with State and Control Constraints and Disturbance Inputs

Reference governors are applied to closed-loop tracking systems that are linear and discrete time and have constraints on state and control variables. Earlier results are extended in signi"cant ways. Disturbance inputs, whose values belong to a speci"ed set, are allowed and a general class of reference governors is introduced. Each governor in the class guarantees constraint satisfaction for all reference and disturbance inputs. Moreover, if the reference input is ultimately con"ned to a neighbourhood of a constraint-admissible constant input, the eventual action of the reference governor reduces to a unit delay. By appropriately selecting reference governors from the allowed class it is possible to simplify signi"cantly their implementation. The increase in on-line speed of operation overcomes prior limits on the practical application of reference governors. Algorithmic procedures are described which facilitate design of the reference governors. Several examples are presented. They illustrate the design process and the excellence of response to large inputs. Copyright ( 1999 John Wiley & Sons, Ltd.