MODEL-BASED FAULT DETECTION AND DIAGNOSIS FOR ELECTROMAGNETIC VALVE DRIVES

ABSTRACT This paper describes the model-based fault detection and diagnosis for electromagnetic actuators. Due to hysteresis behavior, the model of Jiles and Atherton is INTRODUCTION Electromagnetic actuators increasingly replace the traditional, purely mechanically, pneumatically, or hydraulically driven actuators. In the area of electro-hydraulic servo axes, directly driven proportional valves replace in many applications the two-stage valves with the traditional nozzle-flapper construction controlled by torque-motors. Wear and tear due to abrasion, erosion, and excessive temperature can severely degrade the operating time. Furthermore, the ongoing integration of electromagnetic actuators in mechatronic systems, puts even more emphasis on the need to detect and diagnose faults autonomously. Signalbased methods such as limit checking or trend checking, which so far have mostly been applied in industry, do not allow the detection of tiny, incipient faults. Typically, the fault becomes large without being detected and therefore, the plant must immediately be shut down when the fault is detected by classical methods. Using modern, process-model based methods, it is however possible to detect and diagnose faults in a much earlier stage and thus prevent the shutdown of the plant by means of fault-management methods, such as reconfiguration of the control, switching-over from a defect to an intact component. The paper will present the design of such a model-based fault detection and diagnosis system for electromagnetic drives