Study on the Driving Style Adaptive Vehicle Longitudinal Control Strategy

This paper presents a fusion control strategy of adaptive cruise control(ACC) and collision avoidance(CA),which takes into account a driver’s behavioral style. First, a questionnaire survey was performed to identify driver type, and the corresponding driving behavioral data were collected via driving simulator experiments, which served as the template data for the online identification of driver type. Then, the driveradaptive ACC/CA fusion control strategy was designed, and its effect was verified by virtual experiments. The results indicate that the proposed control strategy could achieve the fusion control of ACC and CA successfully and improve driver adaptability and comfort.

Eye-Movement Characteristics of Drivers According to Driving Experience-Relevance to Traffic Sign Legibility

An experiment was conducted to find the variability of driver eye movement according to different driving experience. An eye tracking system was used to study the regularity of driver eye movements, such as fixation duration, variations of fixation points, and the distribution of glance zone. It was found that driving experience had a significant effect on driver eye movement behavior. The percentage of fixation duration to total glance time for inexperienced drivers was 61.5%, while the percentage for experienced drivers was 50.2%. Moreover, the majority of drivers paid attention to the left region of the field of view more frequently than the central and the right regions. This study indicates that it takes inexperienced drivers more time to recognize traffic signs. The findings from this study will assist traffic engineers in designing and installing the traffic signs in an optimal way.

Effect of Wave Accessibility on Lower Hybrid Wave Current Drive in Experimental Advanced Superconductor Tokamak with H-Mode Operation

The effect of the wave accessibility condition on the lower hybrid cm＇rent drive in the experimental advanced superconductor Tokamak （EAST） plasma with H-mode operation is studied. Based on a simplified model, a mode conversion layer of the lower hybrid wave between the fast wave branch and the slow wave branch is proved to exist in the plasma periphery for typical EAST H-mode parameters. Under the framework of the lower hybrid wave simulation code （LSC）, the wave ray trajectory and the associated current drive are calculated numerically. The results show that the wave accessibility condition plays an important role on the lower hybrid current drive in EAST plasma. For wave rays with parallel refractive index n｜｜= 2.1 or n｜｜ = 2.5 launched from the outside midplane, the wave rays may penetrate the core plasma due to the toroida] geometry effect, while numerous reflections of the wave ray trajectories in the plasma periphery occur. However, low current drive efficiency is obtained. Meanwhile, the wave accessibility condition is improved if a higher confined magnetic field is applied. The simulation results show that for plasma parameters under present EAST H-mode operation, a significant lower hybrid wave current drive could be obtained for the wave spectrum with peak value n｜｜ = 2.1 if a toroidal magnetic field BT =2.5 T is applied.

Experimental Research on Lower Hybrid Current Drive in Superconducting Tokamak HT-7

?Fundamental experiments on lower hybrid current drive (LHCD) have been undertaken on HT-7 superconducting tokamak. The experiments on LHCD efficiency reveal its depen- deuce on plasma density and the toroidal magnetic field. Furthermore, the experiments on HT-7 successfully demonstrate the ability for LHCD to sustain long pulse tokamak discharges, such as discharges with full non-inductive current drive for several seconds. The experimental study to improve plasma confinements by LHCD suggests that the improvement should be due to the change o f current profile. It has also been demonstrated by the experiments that the lower hybrid wave may lead to an enhanced ionization of particles in the region where the wave is deposited.

Influence analysis of chevron alignment signs on drivers' speed choices at horizontal curves on highways

Using a driving simulator,the effects of Chinese chevrons on drivers’actual and perceived safe speeds at horizontal curves on two-lane rural highways are tested. Twelve horizontal curves with different roadway geometries are designed and used as the simulated scenarios.The results show that, regardless of the curve radius, chevrons at horizontal curves provide advance warning and speed control for vehicles on the nearside of chevrons.Besides,chevrons can be used as an addition to speed limit signs in preventing excessive speed at horizontal curves and, therefore, can contribute to a reduction in run-off-road crashes.Moreover, Chinese chevrons can also serve to provide an improved sense of safety while driving around sharp curves.These study results lay a foundation for setting Chinese chevrons more reasonably.

Research on the classification for road traffic visibility based on the characteristics of driving behaviour–a driving simulator experiment

Purpose–The purpose of this paper is to performfine classification of road traffic visibility based on the characteristics of driving behavior under different visibility conditions.Design/methodology/approach–A driving simulator experiment was conducted to collect data of speed and lane position.ANOVA was used to explore the difference in driving behavior under different visibility conditions.Findings–The results show that only average speed is significantly different under different visibility conditions.With the visibility reducing,the average vehicle speed decreases.The road visibility conditions in a straight segment can be divided intofive levels:less than 20,20-30,35-60,60-140 and more than 140 m.The road visibility conditions in a curve segment can be also divided into four levels:less than 20,20-30,35-60 and more than 60 m.Originality/value–Afine classification of road traffic visibility has been performed,and these classifications help to establish more accurate control measures to ensure road traffic safety under low-visibility conditions.

Behavioral adaptation of drivers when driving among automated vehicles

Purpose–This paper aims to explore whether drivers would adapt their behavior when they drive among automated vehicles(AVs)compared to driving among manually driven vehicles(MVs).Understanding behavioral adaptation of drivers when they encounter AVs is crucial for assessing impacts of AVs in mixed-traffic situations.Here,mixed-traffic situations refer to situations where AVs share the roads with existing nonautomated vehicles such as conventional MVs.Design/methodology/approach–A driving simulator study is designed to explore whether such behavioral adaptations exist.Two different driving scenarios were explored on a three-lane highway:driving on the main highway and merging from an on-ramp.For this study,18 research participants were recruited.Findings–Behavioral adaptation can be observed in terms of car-following speed,car-following time gap,number of lane change and overall driving speed.The adaptations are dependent on the driving scenario and whether the surrounding traffic was AVs or MVs.Although significant differences in behavior were found in more than 90%of the research participants,they adapted their behavior differently,and thus,magnitude of the behavioral adaptation remains unclear.Originality/value–The observed behavioral adaptations in this paper were dependent on the driving scenario rather than the time gap between surrounding vehicles.This finding differs from previous studies,which have shown that drivers tend to adapt their behaviors with respect to the surrounding vehicles.Furthermore,the surrounding vehicles in this study are more“free flow’”compared to previous studies with a fixed formation such as platoons.Nevertheless,long-term observations are required to further support this claim.

Analysis of female drivers’ ECG characteristics within the context of connected vehicles

Purpose–This study aims to analyze the differences of electrocardiograph(ECG)characteristics for female drivers in calm and anxious states during driving.Design/methodology/approach–The authors used various materials(e.g.visual materials,auditory materials and olfactory materials)to induce drivers’mood states(calm and anxious),and then conducted the real driving experiments and driving simulations to collect driver’s ECG signal dynamic data.Physiological changes in ECG during the stimulus process were recorded using PSYLAB software.The paired T-test analysis was conducted to determine if there is a significant difference in driver’s ECG characteristics between calm and anxious states during driving.Findings–The results show significant differences in the characteristic parameters of female driver’s ECG signals,including(average heart rate),(atrioventricular interval),(percentage of NN intervals>50ms),(R wave average peak),(Root mean square of successive),(Q wave average peak)and(S wave average peak),in time domain,frequency domain and waveform in emotional states of calmness and anxiety.Practical implications–Findings of this work show that ECG can be used to identify driver’s anxious and calm states during driving.It can be used for the development of personalized driver assistance system and driver warning system.Originality/value–Only a few attempts have been made on the influence of human emotions on physiological signals in the transportationfield.Hence,there is a need for transport scholars to begin to identify driver’s ECG characteristics under different emotional states.This study will analyze the differences of ECG characteristics for female drivers in calm and anxious states during driving to provide a theoretical basis for developing the intelligent and connected vehicles.