Journal of Beijing Institute of Technology (English Edition)最新文献_第7页

Improved Delay Priority Resource Scheduling with Low Packet Loss Rate for MBMS in LTE Systems LTE系统中MBMS低丢包率延迟优先级资源调度的改进

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-09-30 DOI: 10.15918/J.JBIT1004-0579.20024

Xin Sun, Yang Yuan, Zhengyu Song

引用次数: 0

Improved Efficiency Test Method for the Motor Controller with SiC MOSFETs 改进的SiC MOSFET电机控制器效率测试方法

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-09-30 DOI: 10.15918/J.JBIT1004-0579.19121

Wei Wang, Q. Song, Yiting Li, Mukhtiar Ahmad

引用次数: 1

Control of Hydraulic Power System by Mixed Neural Network PID in Unmanned Walking Platform 无人步行平台液压动力系统的混合神经网络PID控制

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-09-30 DOI: 10.15918/J.JBIT1004-0579.20019

Jun Wang, Yanbin Liu, Yi Jin, Youtong Zhang

{"title":"Control of Hydraulic Power System by Mixed Neural Network PID in Unmanned Walking Platform","authors":"Jun Wang, Yanbin Liu, Yi Jin, Youtong Zhang","doi":"10.15918/J.JBIT1004-0579.20019","DOIUrl":"https://doi.org/10.15918/J.JBIT1004-0579.20019","url":null,"abstract":"To speedily regulate and precisely control a hydraulic power system in a unmanned walking platform (UWP), based on the brief analysis of digital PID and its shortcomings, dual control parameters in a hydraulic power system are given for the precision requirement, and a control strategy for dual relative control parameters in the dual loop PID is put forward, a load and throttle rotation-speed response model for variable pump and gasoline engine is provided according to a physical process, a simplified neural network structure PID is introduced, and formed mixed neural network PID(MNN PID)to control rotation speed of engine and pressure of variable pump, calculation using the back propagation(BP) algorithm and a self-adapted learning step is made, including a mathematic principle and a calculation flow scheme, the BP algorithm of neural network PID is trained and the control effect of system is simulated in Matlab environment, real control effects of engine rotation speed and variable pump pressure are verified in the experimental bench. Results show that algorithm effect of MNN PID is stable and MNN PID can meet the adjusting requirement of control parameters.","PeriodicalId":39252,"journal":{"name":"Journal of Beijing Institute of Technology (English Edition)","volume":"29 1","pages":"273-282"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46740907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Optimal Design of Improved L-shaped Coprime Array Based on Difference and Sum Co-array 基于差和共阵列的改进型L形互质阵列的优化设计

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-09-30 DOI: 10.15918/J.JBIT1004-0579.20049

Rui Fang, Xiangnan Li, Haixia Wu, Wei Gao, Shiwei Ren

引用次数: 0

Spray Characteristics of Air-Assisted Injector Under Different Ambient Pressures 空气辅助喷射器在不同环境压力下的喷雾特性

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-09-30 DOI: 10.15918/J.JBIT1004-0579.20036

Hao Wu, Fujun Zhang, Zhenyu Zhang

{"title":"Spray Characteristics of Air-Assisted Injector Under Different Ambient Pressures","authors":"Hao Wu, Fujun Zhang, Zhenyu Zhang","doi":"10.15918/J.JBIT1004-0579.20036","DOIUrl":"https://doi.org/10.15918/J.JBIT1004-0579.20036","url":null,"abstract":"Spray atomization of liquid fuel plays an important role in droplet evaporation, combustible mixture formation and subsequent combustion process. Well-atomized liquid spray contributes to high fuel efficiency and low pollutant emissions. Gasoline direct injection(GDI) has been recognized as one of the most effective ways to improve fuel atomization. As a special direct injection method, the air-assisted direct injection utilizes high-speed flow of high-pressure air at the injector exit to assist liquid fuel injection and promote spray atomization at a low injection pressure. This injection method has excellent application potential and advantages for high performance and lightweight engines. In this study, the hollow cone spray emerging from an air-assisted injector was studied in a constant volume chamber with the ambient pressures ranging from 5 kPa to 300 kPa. External macro characteristics of spray were obtained using high speed backlit imaging. Phase Doppler particle analyzer(PDPA) was utilized to study the microcosmic spray characteristics. The results show that under the flash boiling condition, the spray will generate a strong flash boiling point which causes the cone shape spray to expand both inwards and outwards. The axisymmetric inward expansion would converge together and form a lathy aggregation area below the nozzle and the axisymmetric outward expansion greatly increases the spray width. The sauter mean diameter (SMD) of flash boiling condition can be reduced to 5 μm compared to the level close to 10 μm in the non-flash boiling condition.","PeriodicalId":39252,"journal":{"name":"Journal of Beijing Institute of Technology (English Edition)","volume":"29 1","pages":"317-325"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44749513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Implementation of MPC-Based Trajectory Tracking Considering Different Fidelity Vehicle Models 考虑不同保真度车辆模型的mpc轨迹跟踪实现

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-09-30 DOI: 10.15918/J.JBIT1004-0579.19101

Shuping Chen, Huiyan Chen, D. Negrut

{"title":"Implementation of MPC-Based Trajectory Tracking Considering Different Fidelity Vehicle Models","authors":"Shuping Chen, Huiyan Chen, D. Negrut","doi":"10.15918/J.JBIT1004-0579.19101","DOIUrl":"https://doi.org/10.15918/J.JBIT1004-0579.19101","url":null,"abstract":"In order to investigate how model fidelity in the formulation of model predictive control(MPC) algorithm affects the path tracking performance, a bicycle model and an 8 degrees of freedom(DOF) vehicle model, as well as a 14-DOF vehicle model were employed to implement the MPC-based path tracking controller considering the constraints of input limit and output admissibility by using a lower fidelity vehicle model to control a higher fidelity vehicle model. In the MPC controller, the nonlinear vehicle model was linearized and discretized for state prediction and vehicle heading angle, lateral position and longitudinal position were chosen as objectives in the cost function. The wheel step steering and sine wave steering responses between the developed vehicle models and the Carsim model were compared for validation before implementing the model predictive path tracking control. The simulation results of trajectory tracking considering an 8-shaped curved reference path were presented and compared when the prediction model and the plant were changed. The results show that the trajectory tracking errors are small and the tracking performances of the proposed controller considering different complexity vehicle models are good in the curved road environment. Additionally, the MPC-based controller formulated with a high-fidelity model performs better than that with a low-fidelity model in the trajectory tracking.","PeriodicalId":39252,"journal":{"name":"Journal of Beijing Institute of Technology (English Edition)","volume":"29 1","pages":"303-316"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47790514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Improved Soft Cancellation Decoding of Polar Codes 改进的极性码软抵消译码

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-09-30 DOI: 10.15918/J.JBIT1004-0579.20008

Ming-Chan You, Zhifeng Ma

引用次数: 0

Evaluation of TBM Cutterhead’s Comprehensive Performance Under Complicated Conditions 复杂条件下TBM刀盘综合性能评价

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-09-30 DOI: 10.15918/J.JBIT1004-0579.20029

Ye Zhu, Xu-liang Wang, Xiangyu Chen

{"title":"Evaluation of TBM Cutterhead’s Comprehensive Performance Under Complicated Conditions","authors":"Ye Zhu, Xu-liang Wang, Xiangyu Chen","doi":"10.15918/J.JBIT1004-0579.20029","DOIUrl":"https://doi.org/10.15918/J.JBIT1004-0579.20029","url":null,"abstract":"A comprehensive performance evaluation method for the tunnel boring machine(TBM) cutterhead is proposed in this paper. The evaluation system is established on strength and vibration. Based on fracture mechanics theory, fatigue strength evaluation indices are determined under critical crack length. The concept of crack regions division is proposed to evaluate fatigue strength more accurately and specifically. In addition, the velocities in three directions of critical locations are obtained with dynamics equations. Then, the root-mean-square values of velocities are taken as the vibration severity indices. Taking the cutterhead of Jilin diversion engineering as an example, the evaluations of each index are completed; then, the vibration of the TBM cutterhead is measured and compared with the theoretical calculation results. There are similar change laws between the theoretical calculation results and the testing results of the cutterhead acceleration, which proves that the method of calculation of the vibration index is effective, the reliability of the cutter saddle welding should be paid attention to when the TBM is working, and the condition of vibration severity of the TBM cutterhead meets the requirements but needs to be improved.","PeriodicalId":39252,"journal":{"name":"Journal of Beijing Institute of Technology (English Edition)","volume":"29 1","pages":"326-338"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46497137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Experimental and Numerical Study on the Gas Explosion in Urban Regulator Station 城市调压站瓦斯爆炸的实验与数值研究

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-01-01 DOI: 10.15918/J.JBIT1004-0579.19115

Zhenyi Liu, Yuanyuan Ma, Y. Ren, Mingzhi Li, Pengliang Li, Song Wan

{"title":"Experimental and Numerical Study on the Gas Explosion in Urban Regulator Station","authors":"Zhenyi Liu, Yuanyuan Ma, Y. Ren, Mingzhi Li, Pengliang Li, Song Wan","doi":"10.15918/J.JBIT1004-0579.19115","DOIUrl":"https://doi.org/10.15918/J.JBIT1004-0579.19115","url":null,"abstract":"Regulator station is an important part in the urban gas transmission and distribution system. Once gas explosion occurs, the real explosion process and consequences of methane gas explosion in the regulator station were not revealed systematically. In this study, a full-scale experiment was carried out to simulate the regulator station explosion process, and some numerical simulations with a commercial CFD software called FLACS were conducted to analyze the effect of ignition and vent conditions on the blast overpressure and flame propagation. The experimental results demonstrated that the peak overpressure increased as the distance from the vent increased within a certain distance. And the maximum overpressure appeared 3 m away from the door, which was about 36.6 kPa. It was found that the pressure-time rising curves obtained from the simulation are basically the same as the ones from the experiment, however, the time of reaching the peak pressure was much shorter. The numerical simulation results show that the peak overpressures show an increase trend as the ignition height decreased and the vent relief pressure increased. It indicates that the damage and peak overpressure of gas explosion could be well predicted by FLACS in different styles of regulator station. In addition, the results help us to understand the internal mechanism and development process of gas explosion better. It also offers technical support for the safety protection of the urban regulator station.","PeriodicalId":39252,"journal":{"name":"Journal of Beijing Institute of Technology (English Edition)","volume":"29 1","pages":"195-208"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67341835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Simplified Modeling and Mathematical Analysis in Cardiac Electric Field Propagation for Human and Animals 人和动物心脏电场传播的简化建模与数学分析

Journal of Beijing Institute of Technology (English Edition) Pub Date : 2020-01-01 DOI: 10.15918/J.JBIT1004-0579.19104

Ping Lang, Lei Han

引用次数: 0