Fault tolerant control using self-diagnostic smart actuator

In this paper, a networked fault tolerant control strategy that utilizes a self-diagnostic smart actuator is presented with an application to ldquosteer-by-wirerdquo (SBW) which is a network based steering system for intelligent cars. Networked control systems (NCS) like SBW have various advantages, such as easy maintenance, low cost implementation and reconfiguration ability. In NCS, it is possible to achieve bi-directional communications using intelligent subsystems called ldquosmart actuators.rdquo Using a built-in processing unit and bi-directional communication, a smart actuator can offer the capability of self-diagnosis and self-compensation resulting in a high level of dependability. This paper highlights the usefulness of such smart actuators from the point of view of enhancing the ability of tolerating actuator faults without any redundant actuators. The proposed approach is mainly relying on an actuator performance index, called effectiveness factor, which can be obtained through self-diagnosis performed by the built-in actuator processor. Simulation results with a SBW system show that the proposed smart actuator-based control system provides fast and accurate control strategy to tolerate faults.