https://users.encs.concordia.ca/~ymzhang/publications/ARC32-2-98Zhang_pp.229-252.pdf

Bibliographical review on reconfigurable fault-tolerant control systems

Fault-Tolerant Control: The 1997 Situation

The article begins with a review of electronic driver assisting systems such as ABS, traction control, electronic stability control, and brake assistant. We then review drive-by-wire systems with and without mechanical backup. Drive-by-wire systems consist of an operating unit with an electrical output, haptic feedback to the driver, bus systems, microcomputers, power electronics, and electrical actuators. For their design safety, integrity methods such as reliability, fault tree and hazard analysis, and risk classification are required. Different fault-tolerance principles with various forms of redundancy are considered, resulting in fail-operational, fail-silent, and fail-safe systems. Fault-detection methods are discussed for use in low-cost components, followed by a review of principles for fault-tolerant design of sensors, actuators, and communication. We evaluate these methods and principles and show how they can be applied to low-cost automotive components and drive-by-wire systems. A brake-by-wire system with electronic pedal and electric brakes is then considered in more detail, showing the design of the components and the overall architecture. Finally, we present conclusions and an outlook for further development of drive-by-wire systems.

Fault-tolerant drive-by-wire systems

The fault-tolerant control problem belongs to the domain of complex control systems in which inter-control-disciplinary information and expertise are required. This paper outlines the state of the art in a field which remains largely a theoretical topic with most application studies based upon aerospace systems. The directions in which the subject is going are summarised and some pointers are given as to the likely future issues and where new research effort is required. The paper provides a basic literature review covering most areas of fault-tolerant control.

Fault-tolerant control systems: the 1997 situation

An integrated fault detection, diagnosis, and reconfigurable control scheme based on interacting multiple model (IMM) approach is proposed. Fault detection and diagnosis (FDD) is carried out using an IMM estimator. An eigenstructure assignment (EA) technique is used for reconfigurable feedback control law design. To achieve steady-state tracking, reconfigurable feedforward controllers are also synthesized using input weighting approach. The developed scheme can deal with not only actuator and sensor faults, but also failures in, system components. To achieve fast and reliable fault detection, diagnosis, and controller reconfiguration, new fault diagnosis and controller reconfiguration mechanisms have been developed by a suitable combination of the information provided by the mode probabilities from the IMM algorithm and an index related to the closed-loop system performance. The proposed approach is evaluated using an aircraft example, and excellent results have been obtained.

Integrated active fault-tolerant control using IMM approach

This article looks at autonomous control reconfiguration, particularly as it relates to fault accommodation and learning systems. To illustrate the types of difficulties encountered and to serve as a focus, two specific approaches are presented. The first approach uses multiple models to represent uncertain system characteristics. The example application is interceptor terminal guidance with unknown target maneuvers. The second approach uses a single model with adaptive techniques for updating uncertain system characteristics.

H.E. Rauch

Papers

Autonomous control reconfiguration