The multiple fault diagnosis problem is important, since the single fault assumption can lead to incorrect or failed diagnoses when multiple faults occur. It is challenging for continuous systems, because faults can mask or compensate each other’s effects, and the solution space grows exponentially with the number of possible faults. We present a qualitative approach to multiple fault isolation...

In this paper, we propose a generalized diagnostic algorithm for the case where more than one fault (output and/or transfer) may be present in the transitions of a system represented by a deterministic finite state machine (FSM). If existing faults are detected, this algorithm permits the generation of a minimal set of diagnoses, each of which is formed by a set of transitions (with specific ty...

We investigate two strategies to guarantee temporal correctness of a combinational circuit. We first propose a new technique to identify and test primitive faults. A primitive fault is a path delay fault that has to be tested to guarantee the performance of the circuit. Primitive faults can consist of single(SPDF’s) or multiple-path delay faults (MPDF’s). Testing strategies for single primitive...

According to numerous studies, there are basic and initial scaling relationship for the geometric and kinematic characteristics of faults. The study area is located in the northern part of the Kerman coal province. The statistical calculations are consisting of:  measure the surface density of faults per unite area and division of the area, determining the direction of the dominant faulting and...

Almost all approaches to model-based diagnosis presume that the system being diagnosed behaves non-intermittently and analyze behavior over a small number (often only one) of time instants. In this paper we show how existing approaches to model-based diagnosis can be extended to diagnose intermittent failures as they manifest themselves over time. In addition, we show where to insert probe poin...

The fault identification in a scenario of multiple concurrent faults is studied for an internal combustion engine exposed to sensor, actuator and structural faults. The focus is on numerical feasible algorithms with fixed timespace behavior that are suitable for real-time application. Two methodologies are tested in simulation. First we show that a single extended Kalman Filter (eKF) can be use...

The diagnosis of multiple faults is significantly more difficult than singular fault diagnosis. However, in realistic industrial systems the possibility of simultaneous occurrence of multiple faults must be taken into account. This paper investigates some of the limitations of the diagnostic model based on the simple binary diagnostic matrix in the case of multiple faults. Several possible inte...

Due to the important role of the boiler-turbine units in industries and electricity generation, it is important to diagnose different types of faults in different parts of boiler-turbine system. Different parts of a boiler-turbine system like the sensor or actuator or plant can be affected by various types of faults. In this paper, the effects of the occurrence of faults on the actuators are in...

This paper discusses the problem of fault diagnosis under multiple sequential faults occurrence. In industrial applications this type of fault is the most common since the continuous operation of systems/processes is required. The fault diagnosis algorithms should cope with such type of multiple faults, but degradation in their fault isolation capabilities is introduced until the point that the...

This paper presents a new approach to detect and isolate the current sensor faults, a doubly fed induction generator (DFIG) for a wind turbine application. And to detect the variable resistance faults. A method using an unknown input of multiple observers described via TakagiSugeno (T-S) multiple models. A bank of multiple observers scheme (DOS) generates a set of residuals for detection and is...