Reconfigurable Fault Tolerant Control of a Boeing 747 Using Subspace Predictive Control

Abstract

This paper presents a fault tolerant control (FTC) system for a Boeing 747. This FTC system is based on a combination of predictive control and subspace identification called subspace predictive control (SPC). In SPC, the mathematical model used by conventional predictive controllers to predict the future output, is replaced by a subspace predictor. Since this subspace predictor is continuously adapted in a closed-loop setting based on past input-output data, it can naturally adapt to the system after a fault has occurred. This property is very useful for FTC since a model of the post-fault system is not required. A novel feature of the presented SPC algorithm is how the predictor is recursively updated in a computationally efficient way. Furthermore, for optimal performance the SPC algorithm is implemented with different settings for different fault types. These settings include the control surfaces that are used for a certain fault type. The fault types are determined by a multiple model fault classification scheme. The proposed FTC system is evaluated on a detailed model of a Boeing 747, which is used in Action Group 16 on FTC of the European GARTEUR project.