Browse Topic: Fault detection
Reliable and safe Redundant Steering System (RSS) equipped with Dual-Winding Permanent Magnet Synchronous Motor (DW-PMSM) is considered an ideal actuator for future autonomous vehicle chassis. The built-in DW-PMSM of the RSS is required to identify various winding’s faults such as disconnection, open circuit, and grounding. When achieving redundant control through winding switching, it is necessary to suppress speed fluctuations during the process of winding switching to ensure angle control precision. In this paper, a steering angle safety control for RSS considering motor winding’s faults is proposed. First, we analyze working principle of RSS. Corresponding steering system model and fault model of DW-PMSM have been established. Next, we design the fault diagnosis and fault tolerance strategy of RSS. Considering the difference in amplitude frequency characteristics of phase current during DW-PMSM winding faults, the Hanning window and Short-Time Fourier Transform (STFT) is
The primary function of this specification is to cover the general requirements for manual reset trip-free arc fault/thermal circuit breakers for use in aircraft electrical systems conforming to MIL-STD-704. As a secondary function, this specification may possibly cover the general requirements for AFCBs for use in primary vehicles, other than aircraft, when mounted directly to the structure
NASA’s System-Wide Safety (SWS) project is developing innovative data solutions to assure safe, rapid, and repeatable access to a transformed National Airspace System. The increasing number of electric propulsion systems that will enter the airspace will require systems that ensure high safety standards in the low-altitude airspace. One element that can help ensure safety is proper diagnosis of failures via Fault Detection and Isolation (FDI). NASA Ames has developed a fault isolation approach for electric powertrains of unmanned aerial vehicles
The use of planetary gearboxes in heavy-duty industries is dominant due to their compact size, large transmission ratio and torque delivery capability with different configurations. Due to their harsh operating conditions, localised gear tooth faults such as cracking and chipping are more common in such gearboxes. Furthermore, localised gear tooth failure initiates distributed gear faults such as pitting and wear on the gear tooth. Therefore, it is necessary to monitor such localised gear faults continuously and detect them at an early stage to prevent sudden and catastrophic failure. In this study, gear tooth localised defects on various gear elements of the planetary gearbox are seeded using Electrical Discharge Machine (EDM). Then the vibration signals from the gearbox are captured. Afterwards, a decision tree algorithm selects the most prominent statistical features from many extracted features. Further, to automate the fault detection process, the k-nearest neighbours (k-NN
Accurate fault diagnosis is critical to the safe and efficient operation of lithium-ion battery systems. However, various faults in battery systems are difficult to detect and isolate due to their similar features. This paper proposes a model-based multi-fault diagnosis method to detect and isolate the current, voltage, and temperature sensor faults, short circuit faults, and connection faults in the lithium-ion battery systems. An electro-thermal model with fault information is established and used to construct the structural model. Structural analysis theory is applied to design diagnostic tests sensitive to multiple faults. To improve the accuracy and robustness of residual generation, the adaptive extended Kalman filter is introduced to battery state estimation. The multi-fault detection and isolation are implemented using residual evaluation based on the cumulative sum algorithm. Furthermore, a fault indicator used to distinguish short circuit and connection faults is presented
While battery range and charging times are getting the most attention when it comes to electric vehicle (EV) charging systems, safety and reliability are a critical part of the equation. Using the right current-sensing methodology can go far to address these concerns
This paper presents a real-time, nonlinear, control-oriented model for a two-stroke, spark-ignition aircraft engine. The safety and reliability of unmanned aerial vehicles (UAVs) are vital for their large-scale usage. Therefore, the design of control systems for normal as well as abnormal operation of UAVs is very essential. Timely detection and isolation of faults in an engine can save the aircraft from catastrophic consequences. Modeling is the first stage in the majority of control methods. This model is designed to be able to accurately and in real-time predict the output of an aircraft engine. Using existing modeling knowledge, a mean-value engine model is developed in this paper. The engine model consists of five submodels named the throttle body model, air dynamics model, fuel dynamics model, rotational dynamics model, and atmospheric model. The first four submodels are responsible for an accurate description of engine dynamics, while the atmospheric model covers the variation
The rolling bearing is a fundamental component of rotating machines and its failure may lead to a catastrophic damage of the system. The incipient and correct identification of faults contribute to an early predictive maintenance plan, which avoids additional costs and sudden breakdowns. The resonant demodulation technique, envelope analysis, is a well-established method widely used to identify failures in rolling bearings. However, this method requires the identification of the frequency region that contains enough information about the faults. Thus, the spectral kurtosis gives the impulsiveness measure of a vibration signal and it is used to identify the frequency region of failure. This paper presents the use of the bat algorithm as an optimization methodology to identify the resonant demodulation parameters using spectral kurtosis as the objective function. Bat algorithm is a recent method based on echolocation behavior becoming a powerful option in face of traditional method as
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