Topic
Condition monitoring
About: Condition monitoring is a research topic. Over the lifetime, 13911 publications have been published within this topic receiving 201649 citations.
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TL;DR: It is shown that initially, when data is acquired from a point machine, it is difficult to detect faults, however, upon the application of a moving average filter, fault conditions can be more straightforwardly detected and diagnosed.
56 citations
TL;DR: A novel hybrid approach based on Optimized Stationary Wavelet Packet Transform for feature extraction and artificial immune system nested within support vectors machines for fault classification and the motor current signatures analysis offers a cost-effective method for BFD is proposed.
Abstract: The demand of condition monitoring of induction motors (IM) is progressively increasing to maintain the performance of several important sectors in industry. This issue is of great importance since it prevents IM from failing and breaking down. As most of IM faults occur in bearings, the bearing fault detection (BFD) has become the main topic targeting the optimization of unscheduled downtime and maintenance cost of IM. Besides, emphasizing the causes and predicting failure consequences depend on the identification of the fault type. This paper is motivated by the advances in signal processing techniques and machine-learning systems. This study proposes a novel hybrid approach for BFD based on Optimized Stationary Wavelet Packet Transform for feature extraction and artificial immune system nested within support vectors machines for fault classification. The motor current signatures analysis offers a cost-effective method for BFD. To evaluate the approach, the current signals were collected under various bearing conditions and load levels. The experiment results prove the efficiency of the proposed approach.
56 citations
Patent•
24 May 2005
TL;DR: In this paper, a vehicle operator condition monitoring system is described, which includes a physical condition monitoring unit such as a camera, a data processing system, a navigation system, and a communication system.
Abstract: A vehicle operator condition monitoring system is provided. In one embodiment, the vehicle condition monitoring system includes a physical condition monitoring unit such as a camera, a data processing system, a navigation system, and a communication system. The physical condition monitoring unit is mounted in a vehicle to monitor at least one physical trait of a vehicle operator. The data processing system is coupled to the physical condition monitoring unit to compare data acquired by the physical condition monitoring unit with rules indicating types of action to be taken. The navigation system is functionally coupled to the data processing system allowing the data processing system to determine the location of the vehicle and the communications system is functionally coupled to the data processing system to allow the data processing system to contact an appropriate entity should the physical condition of the vehicle operator warrant such contact.
56 citations
TL;DR: In this article, a method for removing the load effects from the monitored quantity of the machine is presented by comparing the actual stator current to a model reference value which includes the load effect Simulation results illustrating the effects on the spectrum of monitored quantity are given for both constant and eccentric air gaps when in the presence of an oscillating load.
Abstract: Fault conditions in induction machines such as eccentric air gaps and broken rotor bars result in harmonics in the stator current of the motor which can be used to monitor the health of the machine. However, variations in the load torque at multiples of rotational speed typically have the same effect on the motor current spectrum. When monitoring a single phase of the stator current, this load effect can prevent the detection of a fault condition by producing current components that obscure those harmonics related to the condition of the machine. This paper presents a new method for removing the load effects from the monitored quantity of the machine. This is accomplished by comparing the actual stator current to a model reference value which includes the load effect Simulation results illustrating the effects on the spectrum of the monitored quantity are given for both constant and eccentric air gaps when in the presence of an oscillating load.
56 citations
TL;DR: This paper analyzes predictive maintenance policies for systems exhibiting 2-phase behavior, and presents cost-minimizing policies, as well as satisfying policies, to determine when monitoring should take place, and for allocating monitoring resources to multiple systems.
Abstract: The deterioration processes of many industrial systems can be modeled in 2-phases. A 2-phase system begins its life in a new condition where it resides for a random amount of time before progressing to a worn condition where it resides for a random amount of time preceding system failure. If monitoring takes place while the system is in the worn condition, preventive maintenance is performed. This paper analyzes predictive maintenance policies for systems exhibiting 2-phase behavior, and presents cost-minimizing policies, as well as satisfying policies, to determine when monitoring should take place, and for allocating monitoring resources to multiple systems. The solution approach is based on decomposing the expected cost (per unit time) into 2 components: the expected cost due to maintenance actions, and the expected cost due to monitoring actions. This decomposition facilitates the construction of operating-characteristic curves that represent policy performance, and allows evaluation of the policy tradeoffs in many situations including those with constrained or unconstrained monitoring resources, multiple or single systems, and fixed or nonfixed monitoring intervals.
56 citations