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Cascade Optimization Control of Unmanned Vehicle Path Tracking Under Harsh Driving Conditions
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作者 黄迎港 罗文广 +1 位作者 黄丹 蓝红莉 《Journal of Shanghai Jiaotong university(Science)》 EI 2023年第1期114-125,共12页
Under ultra-high-speed and harsh conditions,conventional control methods struggle to ensure the path tracking accuracy and driving stability of unmanned vehicles during the turning process.Therefore,this study propose... Under ultra-high-speed and harsh conditions,conventional control methods struggle to ensure the path tracking accuracy and driving stability of unmanned vehicles during the turning process.Therefore,this study proposes a cascade control to solve this problem.Based on the new vehicle error model that considers vehicle tire sideslip and road curvature,the feedforward-parametric adaptive linear quadratic regulator(LQR)and proportional integral control-based speed-keeping controllers are used to compose the path-tracking cascade optimization controller for unmanned vehicles.To improve the adaptability of the unmanned vehicle path-tracking control under harsh driving conditions,the LQR controller parameters are automatically adjusted using a back-propagation neural network,in which the initial weights and thresholds are optimized using the improved grey wolf optimization algorithm according to the driving conditions.The speed-keeping controller reduces the impact on the curve-tracking accuracy under nonlinear vehicle speed variations.Finally,a joint model of MATLAB/Simulink and CarSim was established,and simulations show that the proposed control method can achieve stable entry and exit curves at ultra-high speeds for unmanned vehicles.Under strong wind and ice road conditions,the method exhibits a higher tracking accuracy and is more adaptive and robust to external interference in driving and variable curvature roads than methods such as the feedforward-LQR,preview and pure pursuit controls. 展开更多
关键词 unmanned vehicles path tracking harsh driving conditions cascade control improved gray wolf optimization algorithm backpropagation neural network
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Modeling for Action of Recovering from Erroneous Driving Condition Based on Revised Decision Tree 被引量:1
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作者 王武宏 沈中杰 杜秋 《Journal of Beijing Institute of Technology》 EI CAS 2002年第1期61-65,共5页
Driving behavior modeling is very important in the research area of road traffic systems safety analysis. The characteristics of action of recovering from erroneous driving condition underlying road traffic accident o... Driving behavior modeling is very important in the research area of road traffic systems safety analysis. The characteristics of action of recovering from erroneous driving condition underlying road traffic accident or incident scenarios is quantitatively analyzed, the model of action of recovering from erroneous driving condition is set up according to the identification of erroneous driving condition and the measurement of correction from erroneous driving condition. And then, the probability of action of recovering from erroneous driving condition has been measured based on a revised decision tree. The measure process uses a combination of test data and subjective judgments of driving behavior. It can provide a very helpful theoretical basis for the further analysis of driving behavior in road traffic system. 展开更多
关键词 road traffic safety driving reliability action of recovering from erroneous driving condition
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The Roll Stability Analysis of Semi-Trailer Based on the Wheel Force
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作者 Dong Wang Siwei Chen +1 位作者 Weigong Zhang Danjie Du 《Computers, Materials & Continua》 SCIE EI 2022年第4期1837-1848,共12页
It is different for the liquid tank semi-trailer to keep roll stability during turning or emergency voidance,and that may cause serious accidents.Although the scholars did lots of research about the roll stability of ... It is different for the liquid tank semi-trailer to keep roll stability during turning or emergency voidance,and that may cause serious accidents.Although the scholars did lots of research about the roll stability of liquid tank semi-trailer in theory by calculating and simulation,how to make an effective early warning of rollover is still unsolved in practice.The reasons include the complex driving condition and the difficulty of the vehicle parameter obtaining.The feasible method used currently is evaluating the roll stability of a liquid tank semi-trailer by the lateral acceleration or the attitude of the vehicle.Unfortunately,the lateral acceleration is more useful for sideslip rather than rollover,and the attitude is a kind of posterior way,which means it is hard to take measures to cope with the rollover accident when the attitude exceeds the safety threshold.Considering the movement of the vehicle is totally caused by the wheel force,the rollover could also be predicted by the changing of the wheel force.Therefore,in this paper,we developed a method to analyze the roll stability by the vertical wheel force.A thorough experiment environment is established,and the effectiveness of the proposed method is verified in real driving conditions. 展开更多
关键词 Roll stability wheel force liquid tank semi-trailer real driving conditions
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Chassis Coordinated Control for Full X-by-Wire Vehicles-A Review 被引量:10
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作者 Lei Zhang Zhiqiang Zhang +2 位作者 Zhenpo Wang Junjun Deng David G.Dorrell 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第2期1-25,共25页
An X-by-wire chassis can improve the kinematic characteristics of human-vehicle closed-loop system and thus active safety especially under emergency scenarios via enabling chassis coordinated control.This paper aims t... An X-by-wire chassis can improve the kinematic characteristics of human-vehicle closed-loop system and thus active safety especially under emergency scenarios via enabling chassis coordinated control.This paper aims to provide a complete and systematic survey on chassis coordinated control methods for full X-by-wire vehicles,with the primary goal of summarizing recent reserch advancements and stimulating innovative thoughts.Driving condition identification including driver’s operation intention,critical vehicle states and road adhesion condition and integrated control of X-by-wire chassis subsystems constitute the main framework of a chassis coordinated control scheme.Under steering and braking maneuvers,different driving condition identification methods are described in this paper.These are the trigger conditions and the basis for the implementation of chassis coordinated control.For the vehicles equipped with steering-by-wire,braking-by-wire and/or wire-controlled-suspension systems,state-of-the-art chassis coordinated control methods are reviewed including the coordination of any two or three chassis subsystems.Finally,the development trends are discussed. 展开更多
关键词 X-by-wire systems Chassis coordinated control driving condition identification Active safety
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Real‑Time Predictive Control of Path Following to Stabilize Autonomous Electric Vehicles Under Extreme Drive Conditions 被引量:6
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作者 Ningyuan Guo Xudong Zhang Yuan Zou 《Automotive Innovation》 EI CSCD 2022年第4期453-470,共18页
A novel real-time predictive control strategy is proposed for path following(PF)and vehicle stability of autonomous electric vehicles under extreme drive conditions.The investigated vehicle configuration is a distribu... A novel real-time predictive control strategy is proposed for path following(PF)and vehicle stability of autonomous electric vehicles under extreme drive conditions.The investigated vehicle configuration is a distributed drive electric vehicle,which allows to independently control the torques of each in-wheel motor(IWM)for superior stability,but bringing control com-plexities.The control-oriented model is established by the Magic Formula tire function and the single-track vehicle model.For PF and direct yaw moment control,the nonlinear model predictive control(NMPC)strategy is developed to minimize PF tracking error and stabilize vehicle,outputting front tires’lateral force and external yaw moment.To mitigate the calcu-lation burdens,the continuation/general minimal residual algorithm is proposed for real-time optimization in NMPC.The relaxation function method is adopted to handle the inequality constraints.To prevent vehicle instability and improve steering capacity,the lateral velocity differential of the vehicle is considered in phase plane analysis,and the novel stable bounds of lateral forces are developed and online applied in the proposed NMPC controller.Additionally,the Lyapunov-based constraint is proposed to guarantee the closed-loop stability for the PF issue,and sufficient conditions regarding recursive feasibility and closed-loop stability are provided analytically.The target lateral force is transformed as front steering angle command by the inversive tire model,and the external yaw moment and total traction torque are distributed as the torque commands of IWMs by optimization.The validations prove the effectiveness of the proposed strategy in improved steering capacity,desirable PF effects,vehicle stabilization,and real-time applicability. 展开更多
关键词 Closed-loop stability Extreme drive conditions Fast optimization Nonlinear model predictive control Path following Vehicle stability bounds
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Exploring traffic safety climate with driving condition and driving behaviour:a random parameter structural equation model approach
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作者 Daiquan Xiao Xiaofei Jin +2 位作者 Xuecai Xu Changxi Ma Quan Yuan 《Transportation Safety and Environment》 EI 2021年第3期304-315,共12页
This study aimed to explore traffic safety climate by quantifying driving conditions and driving behaviour.To achieve the objective,the random parameter structural equation model was proposed so that driver action and... This study aimed to explore traffic safety climate by quantifying driving conditions and driving behaviour.To achieve the objective,the random parameter structural equation model was proposed so that driver action and driving condition can address the safety climate by integrating crash features,vehicle profiles,roadway conditions and environment conditions.The geo-localized crash open data of Las Vegas metropolitan area were collected from 2014 to 2016,including 27 arterials with 16827 injury samples.By quantifying the driving conditions and driving actions,the random parameter structural equation model was built up with measurement variables and latent variables.Results revealed that the random parameter structural equation model can address traffic safety climate quantitatively,while driving conditions and driving actions were quantified and reflected by vehicles,road environment and crash features correspondingly.The findings provide potential insights for practitioners and policy makers to improve the driving environment and traffic safety culture. 展开更多
关键词 traffic safety culture traffic safety climate random parameter structural equation model driving condition driving behaviour
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Supplement and optimization of classical capillary number experimental curve for enhanced oil recovery by combination flooding 被引量:3
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作者 QI LianQing LIU ZongZhao +5 位作者 YANG ChengZhi YIN YanJun HOU JiRui ZHANG Jian HUANG Bo SHI FengGang 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第11期2190-2203,共14页
In the middle of the last century,American scientists put forward the concept of capillary number and obtained the relation curve between capillary number and residual oil through experiments.They revealed that the co... In the middle of the last century,American scientists put forward the concept of capillary number and obtained the relation curve between capillary number and residual oil through experiments.They revealed that the corresponding residual oil saturation decreased with increasing of capillary number;after capillary number reached up to a limit,residual oil saturation would become stable and did not decrease.These important achievements laid a theoretical base for enhanced oil recovery with chemical flooding.On the basis of the theory,scholars developed chemical flooding numerical simulation software UTCHEM.During the numerical simulation study of combination flooding,the authors found that as the capillary number is higher than the limit capillary number,the changes of the residual oil saturation along with the capillary number differ from the classical capillary number curve.Oil displacement experiments prove that there are defects in classic capillary number experimental curve and it is necessary to mend and improve.Capillary number‘calculation’curve is obtained with a method of numerical simulation calculation and a complete description of capillary number curve is provided;On this basis,combination flooding capillary number experimental curve QL is obtained through experiments,which is different from the classical capillary curve;and based on which,an expression of corresponding combination flooding relative permeability curve QL is given and the corresponding relative permeability parameters are determined with experiments.Further oil displacement experiment research recognizes the cause of the singular changes of the capillary number curve."Combination flooding capillary number experimental curve QL"and"combination flooding relative permeability curve QL"are written in combination flooding software IMCFS,providing an effective technical support for the application of combination flooding technical research. 展开更多
关键词 numerical simulation driving conditions interfacial tension capillary number combination flooding surfactant concentration wettability conversion
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