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For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Optimal Slip Ratio Identification Estimator Design Based on μ-S Model WANG Bo, DING Fang, LIU Mingyan, TIAN Miaofa Journal of Jishou University(Natural Sciences Edition)    2023, 44 (5): 48-56.   DOI: 10.13438/j.cnki.jdzk.2023.05.007 Abstract （109）      PDF（pc） （1442KB）（89）       Knowledge map    Save In order to achieve optimal control of the automotive anti-lock controller based on slip ratio identification,an optimal slip ratio identification estimator is designed based on the Kiencke μ-S model using an improved forgetting factor recursive least squares algorithm,and the estimation results of the identification estimator regarding the optimal slip ratio and peak adhesion coefficient are compared with those under the Burckhardt μ-S model.The discriminative estimator is applied to the fuzzy sliding mode controller of the automotive anti-lock braking system,and simulation experiments are conducted under single pavement and variational pavement conditions.The experimental results show that the discriminative estimator has small errors and delays,and the anti-lock controller based on the optimal slip ratio identification can achieve online identification and fast tracking of the optimal slip ratio and effectively improve the braking efficiency. Reference | Related Articles | Metrics | Comments（0） Select Prediction of Vertical Displacement of Bridge Excavation Based on Neural Network LI Jiawen, WANG Chongxu, WANG Hao Journal of Jishou University(Natural Sciences Edition)    2022, 43 (2): 53-59.   DOI: 10.13438/j.cnki.jdzk.2022.02.009 Abstract （301）      PDF（pc） （2009KB）（88）       Knowledge map    Save Based on BP neural network method,the vertical deformation prediction of excavation under the bridge is studied.Firstly,the parameter sensitivity of different soil layers is studied and analyzed.It is concluded that the vertical displacement is only sensitive to the parameter change of the first layer of soil.And then,the control parameters of the neural network are determined as cohesion,internal friction angle,elastic modulus,Poisson's ratio,excavation depth,and excavation length of the first layer of soil.The B-R method is used for iterative calculation Verification of the established network show that the prediction accuracy of the model is high. Reference | Related Articles | Metrics | Comments（0） Select Power Limit of Locomotive Traction Motor Under Abnormal Working Conditions CHEN Gang, CHEN Xixiang Journal of Jishou University(Natural Sciences Edition)    2022, 43 (2): 60-67.   DOI: 10.13438/j.cnki.jdzk.2022.02.010 Abstract （504）      PDF（pc） （653KB）（127）       Knowledge map    Save Under abnormal conditions,it is necessary to effectively limit the traction motor power to ensure the normal and safe operation of electric locomotive. On the basis of expounding the influence  of the unlimited traction motor output power of electric locomotive on the converter module and the motor,ther esearch focuses on the analysis of the principle of limiting the output power of traction motor under the conditions of abnormal traction network voltage,abnormal cooling water temperature,abnormal traction motor temperature and fault of traction converter module,and then puts forward the specific implementation scheme of power distribution of traction motor under the power limitation mode. The test results show that the electric locomotive can operate according to the set power limit under different abnormal conditions or fault conditions,which verifies  the power distribution scheme of locomotive traction motor under power limit conditions. Reference | Related Articles | Metrics | Comments（0） Select Influence of the Middle Wall on the Mechanical Characteristics of Frame Bridges WANG Jianxing, LI Zhuoyu, SUN Xueqian, SHI Qingyun Journal of Jishou University(Natural Sciences Edition)    2021, 42 (1): 54-60.   DOI: 10.13438/j.cnki.jdzk.2021.01.009 Abstract （1117）      PDF（pc） （3565KB）（320）       Knowledge map    Save This paper takes an actual  frame bridge as the engineering background, establishes a model of the bridge under design load, and analyzes the influence of the middle wall on the mechanical characteristics of the frame bridge. Comparative research shows that the extreme values of the top and bottom plates of the frame bridges decrease in vertical displacement, vertical axial force, shear stress; the extreme values of the curvature change and cross-sectional stress of the top plates decrease,  while those of the bottom places increase. The research also shows that the vertical displacement of the top plates is most obviously affected by the middle wall and the shear stress of the bottom plates is lest affected by the middle wall. Reference | Related Articles | Metrics | Comments（0） Select Active Earth Pressure Calculation of Retaining Wall with Hoek-Brown Criterion SUN Wangcheng, ZHANG Daobing, JIANG Jin, YU Biao, YIN Huadong Journal of Jishou University(Natural Sciences Edition)    2021, 42 (1): 61-65.   DOI: 10.13438/j.cnki.jdzk.2021.01.010 Abstract （895）      PDF（pc） （471KB）（274）       Knowledge map    Save Based on the logarithmic spiral failure mechanism of the retaining wall and  the nonlinear Hoek-Brown strength criterion, the earth gravity power, internal energy dissipation rate and active earth pressure power of the retaining wall are calculated by the upper limit analysis method. The analytic formula of active earth pressure of the retaining wall is derived based on the virtual power principle, and the optimal upper limit solution of the active earth pressure is solved by Matlab software. The influence of Hoek-Brown strength criterion, retaining wall and soil parameters on the active earth pressure and stability of the retaining wall are analyzed. The results show that with the increase of disturbance factor, wall back angle, retaining wall height, and soil bulk density, the active earth pressure increases nonlinearly, and the stability of the retaining wall decreases. As the geological strength index, rock mass constant, external friction angle, and uniaxial compressive strength increase, the active earth pressure nonlinearly decreases, and the stability of the retaining wall increases. Reference | Related Articles | Metrics | Comments（0） Select Transient Dynamic Response of Frame Bridge to Train at Different Speeds WANG Jianxing, Minabai·Maimaitituerxun, HUANG Yilong Journal of Jishou University(Natural Sciences Edition)    2020, 41 (6): 51-55.   DOI: 10.13438/j.cnki.jdzk.2020.06.010 Abstract （750）      PDF（pc） （2552KB）（205）       Knowledge map    Save With an ordinary concrete frame bridge project as the research object, a numerical model of concrete frame bridge was established with the solid element Solid65 in the finite element analysis software. The deflection-time curve of the mid-span joints of the frame bridge was obtained through transient dynamic calculation and analysis of the complete method, which  reflected the dynamic response characteristics, the displacement characteristics of the frame bridge when the train  passed through the frame bridge at different speeds. The analysis results  showed that 120~150 km/h was the optimal speed interval for the train to  pass through the frame bridge. At this speed interval, the dynamic deflection time-history curve of the frame bridge  tended to be flat, and the maximum deformation of the bridge body  was 1.88×10-2mm which  occurred near the mid-span  before and after the train  passed through the mid-span. Reference | Related Articles | Metrics | Comments（0） Select Simulation of Insulator Contamination Characteristics Based on CFD CHEN Guangsi, NIU Yibo, XI Yun Journal of Jishou University(Natural Sciences Edition)    2020, 41 (6): 56-60.   DOI: 10.13438/j.cnki.jdzk.2020.06.011 Abstract （679）      PDF（pc） （1658KB）（234）       Knowledge map    Save In order to study the contamination characteristics of insulator at different voltages, the wind flow field and electric field in sandstorm were simulated based on fluid mechanics theory and electric field theory. The research shows that contamination of insulator is different at different voltages. When the flow velocity around the insulator is small, the voltage at both ends of the insulator increases, which will lead to the increase of the contamination quantity, and the contamination is closely related to the change of electric field force. When the surrounding flow velocity is large, even if the voltage increases, the contamination quantity will not change too much. Reference | Related Articles | Metrics | Comments（0） Select Analyses of Cargo Throughput Capacity of Main U. S. A. Ports  Based on the Geographical Group DENG Lijuan, WU Qiang Journal of Jishou University（Natural Sciences Edition)    DOI: 10.13438/j.cnki.jdzk.2019.06.017