Uniform Parameters Research Articles

Object recognition algorithm based on optimized nonlinear activation function-global convolutional neural network

Traditional object recognition algorithms cannot meet the requirements of object recognition accuracy in the actual warehousing and logistics field. In recent years, the rapid development of the deep learning theory has provided a technical approach for solving the above problems, and a number of object recognition algorithms has been proposed based on deep learning, which have been promoted and applied. However, deep learning has the following problems in the application process of object recognition: First, the nonlinear modeling ability of the activation function in the deep learning model is poor; second, the deep learning model has a large number of repeated pooling operations during which information is lost. In view of these shortcomings, this paper proposes multiple-parameter exponential linear units with uniform and learnable parameter forms and introduces two learned parameters in the exponential linear unit (ELU), enabling it to represent piecewise linear and exponential nonlinear functions. Therefore, the ELU has good nonlinear modeling capabilities. At the same time, to improve the problem of losing information in the large number of repeated pooling operations, this paper proposes a new global convolutional neural network structure. This network structure makes full use of the local and global information of different layer feature maps in the network. It can reduce the problem of losing feature information in the large number of pooling operations. Based on the above ideas, this paper suggests an object recognition algorithm based on the optimized nonlinear activation function-global convolutional neural network. Experiments were carried out on the CIFAR100 dataset and the ImageNet dataset using the object recognition algorithm proposed in this paper. The results show that the object recognition method suggested in this paper not only has a better recognition accuracy than traditional machine learning and other deep learning models but also has a good stability and robustness.

Field Performance Evaluation of a Small-Scale Drip Irrigation System Installed in the Upper West Region of Ghana

This study was conducted to evaluate the water application uniformity for a drip irrigation system, considering the water quality and the duration of usage. The uniformity parameters, Emission Uniformity (EU %) and Uniformity Coefficient (UC %) were determined for the drip irrigation system installed over a year of performance. The procedures are based on taking measurements of emitter discharge along selected driplines on a sub-main. The catch can be identified as L1A, L1B, L1C, L1D, same for L2A to L2D, L3A to L3D and L4A to L4D. This gave a total of sixteen (16) measurement positions as there were 4 driplines. Results indicated that the uniformity of water application was 90% indicating that the emitter was still good after a year of installation. The average discharge rate was 0.57 l/h. The uniformity coefficient (UC %) for the gravity-fed drip irrigation system was 78%, indicating good water application and was quite significant for the evaluation of the uniform distribution of water for the design. The expansion of this irrigation method in rural communities could contribute to relevant water savings in most areas of the Upper West Region of Ghana.

Evaluation of the Efficiency of the Micro-irrigation Systems in Gardens of Chaharmahal and Bakhtiari Province of Iran

The supply of food security of the society requires the stability of the water resources, that’s requiring the management of optimal water consumption. For this purpose, a research project was conducted to evaluate the efficiency and improvement of optimal water consumption in the gardens of Chaharmahal and Bakhtiari Province. After identifying micro-irrigation plans in the province, 16 plans were selected randomly in different climates and levels. The evaluation indexes were selected based on the instruction of the U.S. Soil Conservation Service (SCS) and American Society of Civil Engineers (ASCE). Parameters of the absolute emission uniformity (EU), the statistical uniformity of Coefficient (Us), efficiency reduction factor (ERF), and flow rate coefficient of variations were obtained. The results indicated that 43.7 percent of the projects being studied had a very good statistical emission uniformity and 31.3 percent showed a Poor and average statistical emission uniformity and 25 percent of the projects had an unacceptable statistical emission uniformity. The flow rate non-uniformity of the droppers and the resulting low coefficients indicated the manipulation of the droppers. The average ERF is 0.717 in the selected projects, which is due to the non-supply of the pressure required in the irrigation systems. The dependence of the Farmers and agricultural operators on government’s aids is one of the main challenges and obstacles of the growth of agriculture and stable productivity in the region.

Parameters Identification of Tunnel Jointed Surrounding Rock Based on Gaussian Process Regression Optimized by Difference Evolution Algorithm

Due to the geological body uncertainty, the identification of the surrounding rock parameters in the tunnel construction process is of great significance to the calculation of tunnel stability. The ubiquitous-joint model and three-dimensional numerical simulation have advantages in the parameter identification of surrounding rock with weak planes, but conventional methods have certain problems, such as a large number of parameters and large time consumption. To solve the problems, this study combines the orthogonal design, Gaussian process (GP) regression, and difference evolution (DE) optimization, and it constructs the parameters identification method of the jointed surrounding rock. The calculation process of parameters identification of a tunnel jointed surrounding rock based on the GP optimized by the DE includes the following steps. First, a three-dimensional numerical simulation based on the ubiquitous-joint model is conducted according to the orthogonal and uniform design parameters combing schemes, where the model input consists of jointed rock parameters and model output is the information on the surrounding rock displacement and stress. Then, the GP regress model optimized by DE is trained by the data samples. Finally, the GP model is integrated into the DE algorithm, and the absolute differences in the displacement and stress between calculated and monitored values are used as the objective function, while the parameters of the jointed surrounding rock are used as variables and identified. The proposed method is verified by the experiments with a joint rock surface in the Dadongshan tunnel, which is located in Dalian, China. The obtained calculation and analysis results are as follows: CR = 0.9, F = 0.6, NP = 100, and the difference strategy DE/Best/1 is recommended. The results of the back analysis are compared with the field monitored values, and the relative error is 4.58%, which is satisfactory. The algorithm influencing factors are also discussed, and it is found that the local correlation coefficient σf and noise standard deviation σn affected the prediction accuracy of the GP model. The results show that the proposed method is feasible and can achieve high identification precision. The study provides an effective reference for parameter identification of jointed surrounding rock in a tunnel.

Experimental study of Thermal performance on heat pipe radiator

The heat pipe radiator has become an effective way to solve the heat dissipation problem of electronic components due to its advantages of good reliability and high-heat dissipation efficiency. So it is necessary to explore the thermal performance of heat pipe radiators.In this paper,gravity radiators with two,four,and six heat pipes are used as the research object.The thermal performance of the three heat pipe radiators with different numbers of heat pipes is compared and analyzed through experiments.It mainly includes the influence of a different number of heat pipes on the heat dissipation power, thermal resistance,temperature uniformity, start-up time and other parameters of the radiator.Research shows that the number of heat pipes is one of the main factors affecting the thermal performance of a radiator. The more heat pipes,the better the thermal performance.

LDNNET: Towards Robust Classification of Lung Nodule and Cancer Using Lung Dense Neural Network

Lung nodule classification plays an important role in diagnosis of lung cancer which is essential to patients' survival. However, because the number of lung CT images in current dataset is relatively small and the ratio of nodule samples to non-nodule samples is usually very different, this makes the training of neural networks difficult and poor performance of neural networks. Hence, LDNNET is proposed, which adopts Dense-Block, batch normalization (BN) and dropout to cope with these problems. Meanwhile, LDNNET is an adaptive architecture based on convnets combining softmax classifier which is utilized to alleviate the problems of training deep convnets. Follows are our main work: Firstly, we utilized LDNNET on database LUng Nodule Analysis 2016 (LUNA16) for lung nodule classification and database KAGGLE DATA-SCIENCE-BOWL-2017(Kaggle DSB 2017) for lung cancer classification; Secondly, the comparison experiments are designed to compare the performance of dense connection, pooling layer and the input pixel size of lung CT(Computed Tomography) images; Thirdly, data enhancement, dense connection and dropout layer were utilized in LDNNET to reduce overfitting; Fourthly, pre-processing methods, for instance enhanced contrast, median filtering, Laplacian filtering are compared to the no-processing method to explore the effect of pre-processing on lung CT images classification. Fifthly, accuracy, specificity and sensitivity on LUNA16 are 0.988396, 0.994585 and 0.982072 and these indicators on Kaggle DSB 2017 are 0.999480, 0.999652 and 0.998974. Furthermore, AUC for both two datasets is over 0.98. Consequently, this paper conducts experiments with uniform parameter settings on two publicly available databases and shows that even in challenging situation where lung images are directly utilized as input images without preprocessing, LDNNET is still the more advanced algorithm than other recent algorithms respectively. Moreover, a series of comparative experiments were conducted to further confirm that the proposed algorithm has the higher accuracy and robustness through verification and discussion.

Tokat-Kazova‘da Mısır Yetiştiriciliğinde Ekim Kalitesinin Değerlendirilmesinde İstatistiksel Proses Kontrol Yaklaşımı

Bu çalışmada, Tokat/Kazova‘da yer alan 10 farklı üreticinin arazilerinde, dane mısır yetiştiriciliğinde uyguladıkları ekim işleminin kalitesinin, İstatistiksel Proses Kontrolü ile değerlendirilmesi amaçlanmıştır. Ekim işleminin kalitesinin belirlenmesinde; tarla filiz çıkış derecesi, sıra üzeri bitki dağılımı ve ekim derinliği düzgünlüğü kullanılmıştır. Sıra üzeri bitki dağılım düzgünlüğü için kabul edilebilir bitki aralığı, ikizlenme oranı ve boşluk oranı belirlenmiştir. Deneme alanlarında tarla filiz çıkış derecesi, %59,60 (D arazisi) ile %93,13 (B arazisi) değerleri arasındadır. Deneme alanlarında kabul edilebilir bitki aralığı, ikizlenme oranı ve boşluk oranı değerleri sırasıyla %65,56 - %90,24, %4,02 – 15,69 ve %5,11 – %12,91 arasında değişmektedir. Sıra üzeri bitki dağılım düzgünlüğü parametrelerine göre yapılan değerlendirmede, deneme alanlarında yapılan ekim işleminin genel olarak ‘Orta‘ ve ‘Yetersiz‘ olduğu sonucuna varılmıştır. Benzer şekilde, sıra üzeri bitki dağılımı ve ekim derinliği düzgünlüğünün İstatistiksel Proses Kontrolü yöntemine göre hazırlanan bireysel ortalama ve hareketli aralık kalite grafikleri de ekim sürecinin kontrol altında olmadığını göstermiştir. Bu sonuçlara göre, sürdürülebilir tarımsal üretim için ekim işleminin kalitesini olumsuz yönde etkileyen faktörlerle ilgili önlem alınması gerekmektedir.

Розрахунок просторового турбулентного потоку в каналах авіаційних газотурбінних двигунів

This work is devoted to the development of approaches to the numerical simulation of 3D turbulent gas flows in different ducts of aircraft gas turbine engines, in particular in inlet device ducts. Inlet devices must provide large values of the total pressure recovery factor and flow uniformity at the engine compressor inlet. The aim of this work is the verification of the operability of a technique developed earlier for the calculation of the parameters of a 3D turbulent flow in complex-shape ducts. The basic approach is a numerical simulation of 3D turbulent gas flows on the basis of the complete averaged Navier¬–Stokes equations and a two-parameter turbulence model. The proposed technique of numerical simulation of a 3D gas flow was tested by calculating a 3D laminar flow in a square pipe bent at a right angle. The calculated flow pattern is in satisfactory agreement with the experimental data on the flow structure in a pipe elbow reported in the literature. Based on a numerical simulation of a 3D turbulent flow in the air duct of one of the air intake configurations for an aircraft turboprop engine, the efficiency of that configuration is assessed. The calculated flow parameter nonuniformity at the air intake outlet, i. e., at the compressor inlet, is compared with that obtained earlier for another air intake configuration for the same engine. It is pointed out that the air intake configuration considered earlier provides a much more uniform flow parameter distribution at the engine compressor inlet. On the whole, this work shows that the quality of subsonic air intakes for aircraft gas turbine engines can be assessed using the proposed numerical technique of 3D gas flow simulation. The results obtained may be used in the aerodynamic improvement of inlet devices for aircraft engines of different types.

DESIGNING TRICKLE IRRIGATION SYSTEM WITH PRESSURE COMPENSATING EMITTERS

The objective of this study was to design the trickle irrigation system by compensating emitters (katif). A field experiment was conducted for 50 m and 75 m of lateral length with outer diameter 16mm and φ13.6mm inner diameter and discharges ( 2, 4 and 8 L /h) and spacing between emitters .5 m. Several points were taken into consideration, such as emitter characteristic friction loss, manufacturing variation, discharge, hydraulic variation. Study compared between lateral at 50m and 75m for friction losses, discharges and lateral length and the primary data of the uniformity parameters (Emission uniformity, Coefficient of uniformity and Coefficient of variation) were calculated and the experiments were done at Collage Farm of Faculty of Agriculture in Menoufia University during 2018. The manufacture coefficient of variation is used as a measure of discharge variation of emitters and manufacturers’ reported discharge rates and coefficients of manufacturing variation (CVm) values were compared with test results for compensating emitters. The effect of compensating emitters ( Katif) and operating pressures (P1 1 and P2 1.5 bar) on the trickle irrigation system hydraulic performance was studied. Compensating emitter (Katif) exponents ranged from 0.06 to 0.2 conducted from curve rate emitter and the measured coefficients of manufacturing variation values for compensating emitters were in the excellent class. As such the variation of discharge through these laterals is restricted by limiting their number to have emission uniformity EU ≥ 90%.

A Numerical Study on the Flow Characteristics and Flow Uniformity of Vanadium Redox Flow Battery Flow Frame

As the demand for electrical energy increases worldwide, the amounts of harmful gases in the atmosphere, such as carbon dioxide released by burning fossil fuel, are continuously increasing. As a result, the interest in renewable energy resources has been growing. However, renewable energies have fluctuating output characteristics according to local conditions such as the natural environment and geographical characteristics, which is a major factor deteriorating output quality. Recently, energy storage systems (ESSs) have been actively studied as a solution to this problem. A redox flow battery (RFB) is a system in which an active material dissolved in an electrolyte is oxidized/reduced to charge/discharge. A RFB mainly consists of an electrolyte tank, which determines the capacity, and a cell stack, which determines the output. As these components can be independently controlled, a RFB provides the advantages of a large capacity and a long lifespan. In this study, a new flow channel was designed to maximize the reaction area and reduce the pump loss to improve RFB performance. Computational fluid dynamics (CFD) and visualization experiments were used to analyze the internal flow characteristics of vanadium redox flow battery (VRFB). Additionally, we used the variability range coefficient and maximum velocity deviation to check if the flow discharged to the electrode was uniform. In the conventional flow frame, the flow discharged to the electrode has a non-uniformity distribution in the left and right, due to the S-shaped path of the inlet channel. In addition, it was confirmed that the outlet area into the electrode was reduced to 50%, resulting in a high pressure drop. To address this problem, we proposed a design that simplified the flow channel, which significantly improved flow uniformity parameters. The maximum velocity deviations for the existing and new flow channels were 11.89% and 54.16%, respectively. In addition, in the entire flow frame for the new flow channel, the pressure drop decreased by 44% as compared with the existing flow channel.

Impact of different scanners and acquisition parameters on robustness of MR radiomics features based on women\u2019s cervix

MR Radiomics based on cervical lesions from one single scanner has achieved promising results. However, it is a challenge to achieve clinical translation. Considering multi-scanners and non-uniform scanning parameters from different centers in a real-world medical scenario, we should first identify the influence of such conditions on the robustness of MR radiomics features (RFs) based on the female cervix. In this study, 9 healthy female volunteers were enrolled and 3 kiwis were selected as references. Each of them underwent T2 weighted imaging in three different 3.0-T MR scanners with uniform acquisition parameters, and in one MR scanner with various scanning parameters. A total of 396 RFs were extracted from their images with and without decile intensity normalization. The RFs’ reproducibility was evaluated by coefficient of variation (CV) and quartile coefficient of dispersion (QCD). Representative features were selected using the hierarchical cluster analysis and their discrimination abilities were estimated by ROC analysis through retrospective comparison with the junctional zone and the outer muscular layer of healthy cervix in patients (n = 58) with leiomyoma. This study showed that only a few RFs were robust across different MR scanners and acquisition parameters based on females’ cervix, which might be improved by decile intensity normalization method.

Thermal Management Optimization of a Lithium-Ion Battery Module with Graphite Sheet Fins and Liquid Cold Plates

Temperature uniformity of lithium-ion batteries and maintaining the temperature within the range for efficient operation are addressed. First, Liquid cold plates are placed on the sides of a prismatic battery, and fins made of aluminum alloy or graphite sheets are applied between battery cells to improve the heat transfer performance. Then a simulation model is built with 70 battery cells and 6 liquid cold plates, and the performance is analyzed according to the flow rate, liquid temperature, and discharge rate. Finally, the results show that temperature differences are mainly caused by the liquid cold plates. The fin surface determines the equivalent thermal conductivity of the battery. The graphite sheets have heterogeneous thermal conductivity, which help improve temperature uniformity and reduce the temperature gradient. With lower density than the aluminum alloy, they offer a lower gravimetric power density for the same heat transfer capacity. In addition to the equivalent thermal conductivity, the temperature difference between the cooling liquid and battery surface is an important parameter for temperature uniformity. Optimizing the fin thickness is found to be an effective way to reduce the temperature difference between the liquid and battery during cooling and improve the temperature uniformity.

Improving radio frequency heating uniformity using a novel rotator for microorganism control and its effect on physiochemical properties of raisins

In the present study, a novel material rotator was designed to evaluate the possibilities to improve radio frequency (RF) heating uniformity in raisins. The rotator provided a means to rotate materials when subjected to RF heating. The results showed that RF heating uniformity was significantly (p < 0.05) improved with the rotation of raisins. The relative heating uniformity parameter (λ) reduced to less than 15% at rotational speed of 40 and 60 rpm. No significant (p > 0.05) influence on heating rate was observed. Pasteurization experiments showed the total bacterial (4.88 log) count was reduced by 2.55 log CFU/g and the molds (4.83 log) were completely inactivated when raisins were heated to 80 °C and maintained for 10 min, which indicated a great disinfection efficiency of RF heating. Quality evaluation showed the physiochemical property changes of raisins were satisfied with acceptable color and nutrients loss. Therefore, the method used in this experiment could be expanded to develop an effective treatment protocol for controlling microorganisms in raisins.

A real-time prediction model for macroseismic intensity in China

The macroseismic intensity spatial distribution is an important input for most rapid loss modeling and emergency work. Data from a total of 175 earthquakes (Ms ≥ 5.0) in China from 1966 to 2014 were collected, and the rapid assessment method of macroseismic intensity distribution was studied. First, simple relationships among the epicentral intensity, magnitude, and focal depth were established. A greater amount of database is used in this study than that in a previous work (Fu and Liu in Sci R 4(5): 350-354 (1960), Mei in Chin J Geophys 9(1): 1–18 (1960), and Yan et al. in Sci Chin 11: 1050-1058 (1984)), and the studied earthquakes all occurred in the last 50 years, providing more accurate and uniform parameter information. As the seismic intensity-attenuation relationship is traditionally used to estimate the intensity distribution, the macroseismic intensity-attenuation relationship for mainland China was fitted by the earthquake data collected in this region. The deviation of the intensity assessment by the macroseismic intensity-attenuation relationship was examined for 43 earthquakes (Ms ≥ 6.0). In addition, seismic damage emergency assessment work requires the isoseismal lines to be constantly modified according to the updated information. Therefore, an improved ellipse intensity-attenuation model was proposed in this study, completed by the establishment of a semimajor axis and semiminor axis length matrix. Based on the initial value of the length matrix obtained by the regression of historical data and survey data from the site, the least mean squares (LMS) algorithm is used to revise the length matrix. In the end, the practicability of this method is verified by a case study of the Lijiang 7.0 earthquake.

Experimental studies on the smoke extraction and smoke control performance by the ventilation shaft in extra-long road tunnels

Ventilation shaft is widely employed in the extra-long road tunnels in China. For deeper understandings of the smoke extraction and smoke control characteristics of the ventilation shaft, a total of 98 experiments were conducted in a 1/20 model scale tunnel. The effects of heat release rate, board location, and operation frequency were investigated. The results indicate that the mechanical board-coupled shaft (MBCS) can achieve better smoke extraction and smoke control performances than the traditional mechanical ventilation shaft (MTS). Though further research on the MBCS, it can be found that smoke extraction and smoke control performance of the MBCS are highly affected by the board location and operation frequency. Besides, as the power of the fire source increases, the smoke extraction performance of the MBCS increases, but the corresponding smoke control will be more difficult. Moreover, it was found that the optimal operation conditions for the MBCS to achieve the best smoke extraction performance and smoke control performance are different. Therefore, the uniform parameter for characterizing both the smoke extraction performance and the smoke control performance was established. And based on this parameter, the overall performance of the MBCS under different operation conditions can be compared, which may contribute positive significance in the smoke control and extraction design with extra-long road tunnels.

Quantitative spatial distribution model of site-specific loess landslides on the Heifangtai terrace, China

Landslide disasters are associated with severe losses on the Loess Plateau of China. Although early warning systems and susceptibility mapping have mitigated this issue to some extent, most methods are qualitative or semi-quantitative in the site-specific range. In this paper, a quantitative spatial distribution model is presented for site-specific loess landslide hazard assessment. Coupled with multi-temporal remote sensing images and high-precision UAV cloud point data, a total of 98 loess landslides that have occurred since 2004 on the Heifangtai terrace were collected to establish a landslide volume-date and retreating distance database. Eleven loess landslides are selected to construct a numerical model for parameter back analysis, and the accuracy of the simulation results is quantitatively evaluated by the centroid distance and overlapping area. Different volumes and receding distance rates of landslides are fitted to determine the relationship between cracks and potential volume, and different volumes and parameters are combined to simulate the spatial distribution of potential loess landslides. The results of this study reveal that landslide volumes mainly range between 1 × 103 and 5 × 105 m3, and the historical occurrence probability reaches 0.551. The optimal parameters are estimated by the maximum likelihood method to obtain a uniform distribution parameter value probability model, and the results show that the error of the estimated length within a range of 0.05 from the optimal parameter does not exceed 15%. In the selected slope slide case, farmland near the toe of the slope primarily includes exposed hazards with probabilities greater than 0.7. This work provides a useful reference for local disaster reduction and a theoretical methodology for hazard assessments.

Risk aggregation in non-life insurance: Standard models vs. internal models

Standard models for capital requirements restrict the correlation between risk factors to the linear measure and disregard undertaking-specific parameters. We consider an alternative framework for risk aggregation in non-life insurance using vine copulas that allow non-linear dependence and are estimated with undertaking-specific parameters. We empirically compare our alternative risk model with three regulatory standard models (Korean risk-based capital, Solvency II, Swiss Solvency Test) and show that the standard models lead to more than 50% higher capital requirements on average. Half of the overestimation results from the uniform parameter selection imposed by regulations and the other half comes from the linear correlation assumption. The differences might distort competition when both standard models and internal risk models are used in a single market.

Computational and analytical measurement of air-fuel mixture uniformity and alternative fuels’ ignition delay in ICEs

Mixing dynamics is a crucial factor for the combustion of fuels in thermal systems such as boilers, rockets, engines, etc. The quality of the mixture is determinate for controlling the ignition and kinetics dynamics progress during premixed and diffusion phases affecting energy conversion and ultimate emission species proliferation in DI diesel engines. In this regard, quantifying the mixture quality computationally in CFD framework and fuel distribution in cells can be a forwarding step in accurate measurement of within-cylinder parameters such as equivalence ratio, pressure, IMEP, thermal efficiency, and emission concentration. This study, in particular, proposes a novel analytical approach based on Heter F(θ) and stoichiometric air/fuel ratio AFRst, and statistical means to obtain an accurate parameter for uniformity of mixture in the cylinder. The new parameter for measuring the mixture quality is based on the standard deviation of the ideal mixture formed in the combustion chamber. The parameter is then used for mathematical ignition delay (ID) modeling for various fuels of diesel, DME, and n-heptane. The conventional models have customarily applied mean pressure (as in Watson model, 1980) or both pressure and equivalence ration (as Assanis, 2003) to compute the ignition delay. However, in this work pressure and modified HF (HF∗) are taken into account which demonstrates 18.3% error reduction with that of Watson and 8.3% reduction for Assanis model when compared to experimental results for diesel-powered engine. The obtained results show a significant agreement of experimental and modeling data for the engine speed ranging 1500–4000 rpm for various fuels of diesel, n-heptane, and DME. The implication of the results encompasses a wide range of application from direct use in industry to UDF and incorporation in software to thermodynamic analysis of energy devices.

Tool Wear Prediction in Single-Sided Lapping Process

Single-sided lapping is one of the most effective planarization technologies. The process has relatively complex kinematics and it is determined by a number of inputs parameters. It has been noted that prediction of the tool wear during the process is critical for product quality control. To determine the profile wear of the lapping plate, a computer model which simulates abrasive grains trajectories was developed in MATLAB. Moreover, a data-driven technique was investigated to indicate the relationship between the tool wear uniformity and lapping parameters such as the position of conditioning rings and rotational speed of the lapping plate and conditioning rings.

A Study on the Influence of Tire Speed and Pressure on Measurement Parameters Obtained from High-Speed Tire Uniformity Testing

In order to improve the test conditions of the tire uniformity test and the effect of the speed and tire pressure on the uniformity parameters, the uniformity test of the tire under different speeds and tire pressure was carried out by a high-speed uniformity test machine, and the experimental data were analyzed and fitted by the regression analysis method. This paper introduces the definition of uniformity and the uniformity parameters of automotive tires; the working principle of a high-speed uniformity testing machine is briefly described, a mathematical model of the uniformity testing machine is established, and the signal acquisition process of the tire uniformity parameters and the calculation method of the uniformity parameters are described. The test result indicates: As the speed increases, the radial force fluctuation, lateral force fluctuation, tangential force fluctuation, and turning torque fluctuation of the tire increase, and the positive torque fluctuation first increases and then decreases; with the increase of tire pressure, the radial force fluctuation and the tangential force fluctuation of the tire increase, and the lateral force fluctuation, the turning torque fluctuation, and the returning moment fluctuation are all reduced. Compared to the low speed uniformity test, the high speed uniformity test can better reflect the uniformity of the tire, reducing the speed of the vehicle can reduce the radial runout and lateral sway of the tire; increasing the tire pressure can reduce the left and right swing of the vehicle.