Fault handling in embedded industrial measurement and control systems: issues and a case study

With increasingly complex control systems used in a variety of commercial, aerospace, and military applications, system faults may occur during system operations. These faults inevitably result in abnormal operations and production shutdown or even disasters. Therefore, improving system reliability has become a major concern in safety-critical systems. This paper primarily addresses the issues in embedded fault-tolerant control system designs and presents a case study on vibration suppression in the aerospace industry. The design issues on embedded control systems such as component failures, sampling jitters and control delay, network-induced delay and packet loss in network transmission are discussed, all of which may have damaging effects on the closed-loop system performance. A case study on vibration control for a launch vehicle payload fairing using multiple embedded PZT actuators are also presented, where an adaptive actuator failure compensation scheme is successfully implemented. Fault-tolerant control turns out to be effective in creating more robust industrial measurement and control systems.