Aiming to diagnosis the mechanical fault precisely, the current research is proposing a method based on the local mean decomposition (LMD) Shannon entropy and improved fuzzy f-means flustering (IFCM). The features are...
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Aiming to diagnosis the mechanical fault precisely, the current research is proposing a method based on the local mean decomposition (LMD) Shannon entropy and improved fuzzy f-means flustering (IFCM). The features are first extracted by using the time-frequency domain method LMD and the Shannon entropy is used to process the original separated product functions (PF) so as to extract the original features. However, the extracted original features are still with high dimensional and include superfluous information. The nonlinear multi-features fusion technique LTSA is used to merge the features and reduce the dimension. Then, based on the extracted features, the IFCM model is used to achieve the mechanical fault diagnosis. In this model, a feature cluster determine function is established to achieve the weighted factor to achieve a better category effect. Case of a bearing test was analyzed and the results proved the effectiveness of the methodology.
Sliding process between asperities of machined metal surface is important to analyse wear mechanisms. Elastic-plastic sliding asperity model based on fractal geometry is proposed in this paper to extend the sliding pr...
Sliding process between asperities of machined metal surface is important to analyse wear mechanisms. Elastic-plastic sliding asperity model based on fractal geometry is proposed in this paper to extend the sliding process of single micro-asperity to a macro-asperity. The contact force, the critical interference and residual interference are calculated with fractal dimension D and fractal roughness G in the multiscale views. The influence of fractal parameters on normal and tangential contact force are studied. The results of the simulation show that the plastic deformation and residual interference are the main factors affecting the contacting force and asperity radius. For smaller G and bigger D surfaces, the sliding interaction of asperities is less remarkable and the plastic force accounts for less in the contact force.
A universal hinge wobble plate power transmission mechanism is *** the composition,working principle and characteristics of the system are *** order to study its kinematics characteristics,this paper established the c...
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A universal hinge wobble plate power transmission mechanism is *** the composition,working principle and characteristics of the system are *** order to study its kinematics characteristics,this paper established the coordinate systems and the mathematical model of the new wobble power transmission mechanism by means of coordinate *** displacement,velocity and acceleration of the piston are analyzed through the mathematical model,and then,the Adams simulation model is established to verify the correctness of the mathematical *** the comparison of MATLAB mathematical model and Adams simulation of virtual prototype,the result shows that the mathematical model is completely *** kinematics analysis shows that compared with the traditional gasoline engine,the new wobble plate engine has the advantages of small vibration and long service *** research of this paper lays the foundation for the subsequent dynamic analysis.
Aiming at the low voltage, high current and low voltage ripple demand of 100G DSP, this paper presents a power design using LTM4650 as the core device. Analyzing the causes and influencing factors of voltage ripple, a...
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Aiming at the low voltage, high current and low voltage ripple demand of 100G DSP, this paper presents a power design using LTM4650 as the core device. Analyzing the causes and influencing factors of voltage ripple, a solution that used multi-phase parallel and the low ESR capacitor was applied, to suppress the voltage ripple. The results of LTspice simulation software and the actual circuit test, proved that the power design can meet the power requirements of 100G DSP and is able to guarantee the stability of the DSP system.
The effective deployment of materiel is one of the key problems for battle *** aim of this paper is to propose a method of materiel deployment which based on *** method can be considered as matching problems:matching ...
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The effective deployment of materiel is one of the key problems for battle *** aim of this paper is to propose a method of materiel deployment which based on *** method can be considered as matching problems:matching the requirement of task to the available weapon or equipment which can provide these capabilities and matching these weapon and equipment to the platforms that carry *** paper use ontology to do definition work and the basic semantic between them,and then use SWRL(Semantic Web Rule Language)to set rules which can be used to reasoning the matching activities and in the end of the paper use an example to show this method is plausible.
A novel retractable suspension structure is proposed for amphibious *** on this structure,the closedloop vector method is used to establish the kinematic model of the ***,based on this model,the numerical calculation ...
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A novel retractable suspension structure is proposed for amphibious *** on this structure,the closedloop vector method is used to establish the kinematic model of the ***,based on this model,the numerical calculation is carried out in MATLAB,and the turning angular displacement,angular velocity,angular acceleration and lifting height are ***,the virtual prototype of the retractable suspension is established in ADAMS,and the simulation is carried *** correctness of the mathematical model is verified by comparing the results of the two softwares.
This paper is devoted to the stability analysis of positive nonlinear singular systems with time-varying delays via Takagi-Sugeno fuzzy modeling. We introduce an auxiliary system to exploit the positivity criterion fo...
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This paper is devoted to the stability analysis of positive nonlinear singular systems with time-varying delays via Takagi-Sugeno fuzzy modeling. We introduce an auxiliary system to exploit the positivity criterion for the singular fuzzy time-delay system. Then, a sufficient condition of α-exponential stability for positive fuzzy singular systems is established, which depends on a given scalar 0 < α < 1 and the bound of time-varying delays. Finally, a numerical simulation is utilized to illustrate the effectiveness of our result.
Intentional deception jamming brings great threat to satellite navigation receiver and seriously influence GNSS application *** repeater deception jamming, an anti-spoofing algorithm based on a single receiver is *** ...
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ISBN:
(纸本)9789811045905
Intentional deception jamming brings great threat to satellite navigation receiver and seriously influence GNSS application *** repeater deception jamming, an anti-spoofing algorithm based on a single receiver is *** the adjacent two times measurement pseudo-range does double differences, and Taylor expansion is applied to the position relationship in *** the condition of the previous time's position information is known, the authenticity of the satellite signal of the next time can be verified according to the position information when it is combined with the least square iterative solution for the double differences *** algorithm is simple, and only a single receiver and pseudo-range measurement data is *** receiver is adopted for the actual experiments, and the result validates the feasibility and effectiveness of the algorithm.
Real-time detection of learner's sitting posture not only helps prevent myopia in time but also promotes the improvement of learning efficiency. However, most of the current sitting detection methods have the shor...
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ISBN:
(纸本)9781510845541
Real-time detection of learner's sitting posture not only helps prevent myopia in time but also promotes the improvement of learning efficiency. However, most of the current sitting detection methods have the shortcomings of low detection variety and recognition rate, et al. Based on this, a sitting posture detection method based on Cartesian plane projection is proposed. The sitting depth images are projected into three Cartesian planes respectively. The background removal, interpolation scaling and normalization are performed for each projection map. The projection feature is obtained and the PCA is used to reduce the dimension of the feature. Finally, the projection feature and the front view HOG feature are fused to generate the new posture feature vector. In the experiment we collected 20 people, each person 14 kinds of sitting posture to form test database and the use of random forest to classify the extracted sitting posture characteristics. The experimental results show that this method can effectively detect the learner's sitting posture and it is superior to the existing method in recognition accuracy and recognition speed.
The main reasons restricting the development of electric vehicles is safety and mileage,which is decided by safety、capacity and cycle life of power *** safety and performance of power battery are greatly affected by ...
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The main reasons restricting the development of electric vehicles is safety and mileage,which is decided by safety、capacity and cycle life of power *** safety and performance of power battery are greatly affected by *** is important to have a simple but accurate model to predict the thermal behavior of batteries under a variety of operating conditions in the initial design of battery thermal management *** paper presents a thermalelectric model for a 37 Ah lithium battery and module using *** is shown that the model can accurately predict the temperature and voltage of the cell in a wide range of operating *** agreement with the measured temperature development has been *** is simple and quick to use the model when lack of CAD *** model can be used for the scale-up of large size batteries and battery packs.
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