Adaptive control system having hedge unit and related apparatus and methods

Abstract

The invention includes an adaptive control system used to control a plant. The adaptive control system includes a hedge unit that receives at least one control signal and a plant state signal. The hedge unit generates a hedge signal based on the control signal, the plant state signal, and a hedge model including a first model having characteristics of the adaptive control system and plant to which the adaptive control system is not to adapt. The hedge signal is used in the adaptive control system to remove the effects of the characteristics from a signal supplied to an adaptation law unit of the adaptive control system so that the adaptive control system does not adapt to the characteristics in controlling the plant.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation under 35 U.S.C. §120 and 37 C.F.R. §1.53(b) of copending U.S. patent application Ser. No. 10 / 602,458, filed on Jun. 23, 2003 which is a continuation of U.S. patent application Ser. No. 09 / 585,106, filed on May 31, 2000, which application claimed the benefit of provisional application no. 60 / 199,615, filed Apr. 25, 2000, which are hereby incorporated herein in their entirety by reference.STATEMENT OF U.S. GOVERNMENT RIGHTS IN THE INVENTION [0002] This invention was made with U.S. Government funding under Contract No. NAG8-1638 awarded by the National Aeronautics and Space Administration (NASA)—Marshall Space Flight Center and Contract No. F49620-98-1-0437 awarded by the Air Force Office of Scientific Research (AFOSR). The U.S. Government has certain rights in the invention.FIELD OF THE INVENTION [0003] The invention is directed to an adaptive control system and related method. More particularly, the inv...

AI Technical Summary

Benefits of technology

The invention provides a method and apparatus for generating a hedge signal to prevent adaptation to characteristics of an adaptive control system and a plant controlled by the system. This hedge signal is used to avoid adverse impact on control of the plant caused by characteristics that would impair or be detrimental to control system's performance and stability. The hedge signal is generated based on a difference between a plant model without the characteristic and a plant model with the characteristic, and can be used in the adaptive control system to remove the effect of the characteristic from a signal supplied to an adaptation law unit of the system. The technical effect of the invention is to improve the control system's performance and stability by preventing adverse impact on control of the plant caused by characteristics that would impair or be detrimental to control system's performance and stability.

Problems solved by technology

However, conventional adaptive control systems have a tendency to adapt to plant or control system characteristics to which they should not.

The control response of adaptive control systems can be greatly diminished when subjected to certain characteristic(s) of the plant or system, and can be rendered unstable in attempting to adapt to these characteristics.

An example of a characteristic that could adversely affect an adaptive control system is a control or authority limit imposed on the control elements of an adaptive control system.

If an operator generates a command signal that exceeds the ability of the control system or plant to respond, adaptation of the control system can render the control system unstable.

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