Dynamic Transfer Among Alternative Controllers and Its Relation to Antiwindup Controller Design

Stefan F Graebe and Anders Ahlén

IEEE Transactions on Control Systems Technology,
vol 4, pp 92-99, January 1996. © 1996 IEEE.

Also: Internal Report UPTEC 94078R, Dept. of Technology, Uppsala University.

Outline:

Undesirable transients are often generated when a control system switches between different control strategies. The paper discusses how to handle such problems, by introducing additional control loops around the latent (non-active) controllers.

Abstract:

Advanced control strategies and modern consulting provide new challenges for the classical problem of bumpless transfer. It can, for example, be necessary to transfer between an only approximately known existing analogue controller and a new digital or adaptive controller without accessing any states. Transfer ought to be bi-directional and not presuppose steady state, so that an immediate back-transfer is possible if the new controller should drive the plant unstable.

We present a scheme that meets these requirements. By casting the problem of bi-directional transfer into an associated tracking control problem, systematic analysis and design procedures from control theory can be applied. The associated control problem also has a correspondence to the design of antiwindup controllers. The paper includes laboratory and industrial applications.

Related publications:

Book Chapter in CRC Control Handbook 1996 on the above theme.
Conference paper (IFAC World Congress 1993), on the above theme.
Report on a systematic technique for scalar anti-windup design.
Conference paper (Reglermöte 96) on multivariable antiwindup design.