基于遗传神经网络的履带行驶系统载荷识别方法

针对煤矿掘进机器人履带行驶系统工作环境恶劣,载荷无法直接有效获取这一工程实际问题,提出了基于遗传神经网络的振动信号载荷识别方法。构建了遗传算法(GA)优化BP(back propagation)神经网络载荷识别模型,采用路试法试验采集了履带小车的5组振动加速度数据和单组应力载荷数据,探讨路面不平度频率和驱动轮啮频等对履带车振动和应力载荷的影响规律;借助快速傅里叶变换(FFT)对原始应力载荷数据进行去噪处理,依据履带小车行驶平顺性指标,利用sym8小波函数对振动加速度信号进行5层特征提取以提高载荷识别的精度,然后将5组小波变换分解的加速度数据和滤波后的应力载荷数据分别作为GA-BP神经网络的输入和输出进行训练及验证,揭示了履带行驶系统运动过程中振动与应力载荷之间的关系。研究结果表明,路面不平度频率、驱动轮啮频及转频为小车振动的主要频率成分,路面不平度引起的振动频率为13.765 Hz,驱动轮啮频为68.25 Hz,转频为3.25 Hz。多组试验得到的BP神经网络最佳隐含层神经元数为63,GA-BP神经网络识别的应力载荷与期望应力载荷具有较高吻合度,相对误差为4.5%,验证了该方法的有效性...     

An exploratory study of the relationship between road rage and crash experience in a representative sample of US drivers

The phenomenon of road rage has been frequently discussed but infrequently examined. Using a representative sample of 1382 US adult drivers, who were interviewed in a 1998 telephone survey, exploratory analyses examined the relationship between self-reported measures of road rage, generally hazardous driving behaviors, and crash experience. Regarding specific road rage behaviors, most respondents reported having engaged in verbal expressions of annoyance; however only 2.45% reported ever having been involved in direct confrontation with another car or driver. After controlling for gender, age. driving frequency, annual miles driven and verbal expression, an angry/threatening driving subscale of road rage was significantly associated with hazardous driving behaviors that included frequency of driving over the legal blood alcohol limit, receipt of tickets in the past year. and habitually exceeding the speed limit as well as crash experience. However, the verbal/frustration expression subscale was not associated with crash experience or hazardous driving indicators, except for number of tickets, after controlling for other crash-related factors such as gender and age. Direct confrontation by deliberately hitting another car or leaving the car to argue with and/or injure another driver was rarely reported. Results suggest that angry/threatening driving is related to crash involvement; however, after controlling for exposure and angry/threatening and hazardous driving the relationship of milder expressions of frustration while driving and crash involvement was not significant.     

Applying the motorcyclist's perspective to improve car drivers' attitudes towards motorcyclists

This study sought to provide a first crucial step in the direction of developing an intervention program aimed at improving safe attitudes and skills among car drivers towards motorcycles. We intended to improve drivers’ attitudes towards motorcyclists by exposing them to demands that motorcyclists face on the road. Car drivers were exposed to hazard perception clips taken from a motorcyclist's perspective, and interactive hazards in a motorcycle simulator. Car hazard perception clips and a car simulator were used as control conditions. A questionnaire assessed participant knowledge and attitudes towards motorcyclists before and after the intervention. After the intervention participants had more empathic- and fewer negative-attitudes, as well as safer attitudes towards motorcyclists. Self-reported attitude-change suggested that the use of motorcycle hazard perception clips was more effective than the simulator, and the intervention was most effective for those car drivers who reported the most negative attitudes prior viewing the clips or riding the simulator. Providing car drivers with a perspective of the motorcyclist may prove to be a useful tool for promoting safer attitudes towards motorcyclists.     

无碳小车轨迹曲线计算研究

无碳小车是连续三届全国大学生工程训练大赛的主题,其中重要环节就是运行轨迹曲线的计算问题。本文就通过MATLAB对无碳小车的轨迹进行仿真计算研究,并通过加工实践结果表明实际轨迹与理论曲线基本吻合。     

Are car daytime running lights detrimental to motorcycle conspicuity?

For a long time, motorcycles were the only vehicles with daytime running lights (DRLs), but this conspicuity advantage has been questioned due to the rapidly increasing introduction of DRLs on cars as well. The present experiment was designed to assess effects of car DRLs on motorcycle perception in a situation that specifically brought attentional conspicuity to bear. Photographs representing complex urban traffic scenes were displayed briefly (250 ms) to 24 participants who had to detect vulnerable road users (motorcyclists, cyclists, pedestrians) appearing at different locations and distances. Car DRLs hampered motorcycle perception compared to conditions where car lights were not on, especially when the motorcycle was at a greater distance from the observer and when it was located in the central part of the visual scene. Car DRLs also hampered the perception of cyclists and pedestrians. Although the globally positive safety effect of car DRLs is generally acknowledged, our study suggests that more attention should be paid to motorcyclists and other vulnerable road users when introducing car DRLs. Several means of improving motorcycle conspicuity in car DRL environments are discussed.     

Comparison of driving simulator performance with real driving after alcohol intake: A randomised,single blind,placebo-controlled,cross-over trial

The purpose of this study was to establish and validate a driving simulator method for assessing drug effects on driving. To achieve this, we used ethanol as a positive control, and examined whether ethanol affects driving performance in the simulator, and whether these effects are consistent with performance during real driving on a test track, also under the influence of ethanol. Twenty healthy male volunteers underwent a total of six driving trials of 1 h duration; three in an instrumented vehicle on a closed-circuit test track that closely resembled rural Norwegian road conditions, and three in the simulator with a driving scenario modelled after the test track. Test subjects were either sober or titrated to blood alcohol concentration (BAC) levels of 0.5 g/L and 0.9 g/L. The study was conducted in a randomised, cross-over, single-blind fashion, using placebo drinks and placebo pills as confounders. The primary outcome measure was standard deviation of lateral position (SDLP; “weaving”). Eighteen test subjects completed all six driving trials, and complete data were acquired from 18 subjects in the simulator and 10 subjects on the test track, respectively. There was a positive dose–response relationship between higher ethanol concentrations and increases in SDLP in both the simulator and on the test track (p < 0.001 for both). In the simulator, this dose–response was evident already after 15 min of driving. SDLP values were higher and showed a larger inter-individual variability in the simulator than on the test track. Most subjects displayed a similar relationship between BAC and SDLP in the simulator and on the test track; however, a few subjects showed striking dissimilarities, with very high SDLP values in the simulator. This may reflect the lack of perceived danger in the simulator, causing reckless driving in a few test subjects. Overall, the results suggest that SDLP in the driving simulator is a sensitive measure of ethanol impaired driving. The comparison with real driving implies relative external validity of the simulator.     

Car insurance and the risk of car crash injury

Despite speculation about the role of vehicle insurance in road traffic accidents, there is little research estimating the direction or extent of the risk relationship. Data from the Auckland Car Crash Injury Study (1998–1999) were used to examine the association between driving an uninsured motor vehicle and car crash injury. Cases were all cars involved in crashes in which at least one occupant was hospitalized or killed anywhere in the Auckland region. Controls were 588 drivers of randomly selected cars on Auckland roads. Participants completed a structured interview. Uninsured drivers had significantly greater odds of car crash injury compared to insured drivers after adjustment for age, sex, level of education, and driving exposure (odds ratio 4.77, 95% confidence interval 2.94–7.75). The causal mechanism for insurance and car crash injury is not easily determined. Although we examined the effects of multiple potential confounders in our analysis including socioeconomic status and risk-taking behaviours, both of which have been previously observed to be associated with both insurance status and car crash injury, residual confounding may partly explain this association. The estimated proportion of drivers who are uninsured is between 5 and 15% in developed countries, representing a significant public health problem worthy of further investigation.     

EEG alpha spindles and prolonged brake reaction times during auditory distraction in an on-road driving study

Driver distraction is responsible for a substantial number of traffic accidents. This paper describes the impact of an auditory secondary task on drivers’ mental states during a primary driving task. N = 20 participants performed the test procedure in a car following task with repeated forced braking on a non-public test track. Performance measures (provoked reaction time to brake lights) and brain activity (EEG alpha spindles) were analyzed to describe distracted drivers. Further, a classification approach was used to investigate whether alpha spindles can predict drivers’ mental states.     

A positive view on road safety: Can ‘car karma’ contribute to safe driving styles?

Many studies in the field of road safety are occupied with studying road unsafety since it generally concentrates on traffic crashes, crash, risk, and aberrant driving behaviour, especially in relation to young drivers. However, this study shows there is scope for thinking about driving and driver training from a different vantage point, that is in terms of safe or normal driving. The findings are reported from four group interviews with young drivers (18–25 years of age); the young drivers discussed their ideas of safe driving and their reasons for using (or not using) safe driving styles. The data show a type of optimistic thinking among young drivers which they call ‘car karma’. This finding offers an opportunity to reconceptualise driving in a way that is focused on normal, safe driving styles, a topic that has received less attention in the past. The paper argues that greater focus on safe driving styles could be more conducive to young drivers actually driving safely than focusing on, for instance, crashes, which on an individual level are relatively rare (Elander et al., 1993, p. 277). Based on empirical research, the first positively stated definition of road safety is proposed based on the notion of ‘car karma’.     

Reliability of drivers in urban intersections

The concept of human reliability has been widely used in industrial settings by human factors experts to optimise the person-task fit. Reliability is estimated by the probability that a task will successfully be completed by personnel in a given stage of system operation. Human Reliability Analysis (HRA) is a technique used to calculate human error probabilities as the ratio of errors committed to the number of opportunities for that error. To transfer this notion to the measurement of car driver reliability the following components are necessary: a taxonomy of driving tasks, a definition of correct behaviour in each of these tasks, a list of errors as deviations from the correct actions and an adequate observation method to register errors and opportunities for these errors. Use of the SAFE-task analysis procedure recently made it possible to derive driver errors directly from the normative analysis of behavioural requirements. Driver reliability estimates could be used to compare groups of tasks (e.g. different types of intersections with their respective regulations) as well as groups of drivers’ or individual drivers’ aptitudes. This approach was tested in a field study with 62 drivers of different age groups. The subjects drove an instrumented car and had to complete an urban test route, the main features of which were 18 intersections representing six different driving tasks. The subjects were accompanied by two trained observers who recorded driver errors using standardized observation sheets. Results indicate that error indices often vary between both the age group of drivers and the type of driving task. The highest error indices occurred in the non-signalised intersection tasks and the roundabout, which exactly equals the corresponding ratings of task complexity from the SAFE analysis. A comparison of age groups clearly shows the disadvantage of older drivers, whose error indices in nearly all tasks are significantly higher than those of the other groups. The vast majority of these errors could be explained by high task load in the intersections, as they represent difficult tasks. The discussion shows how reliability estimates can be used in a constructive way to propose changes in car design, intersection layout and regulation as well as driver training.     

On the training and testing of entry-level commercial motor vehicle drivers

This study examined the effectiveness of 3 different training types on commercial motor vehicle (CMV) drivers’ skill levels. The training types included a conventional 8-week certified course, a conventional 8-week certified course with approximately 60% of driving time spent in a CMV driving simulator, and a Commercial Driver's License (CDL) test focused short course. Participants’ scores on the Division of Motor Vehicles (DMV) road and range tests were assessed. In addition to their DMV scores, participants replicated DMV road and range driving tests in an instrumented vehicle and the CMV driving simulator. Results indicated no training group differences in DMV road tests. There were differences between training groups on DMV range tests and real truck and simulator versions of the DMV road and range tests; on these tests conventional- and simulator-trained participants generally scored higher than CDL-focused participants. However, all groups performed higher in the real truck than in the simulator for both road and range tests. These findings indicate the need for a minimum standard of entry-level CMV driver training as well as support of the use of a driving simulator for training entry-level drivers; however, testing using a simulator does not appear to be feasible with current technology.     

Validity and reliability of the on-road driving assessment with senior drivers

The on-road driving assessment is widely regarded as the criterion measure for driving performance despite a paucity of evidence concerning its psychometric properties. The purpose of this study was 2-fold. First, we examined the psychometric properties of an on-road driving assessment with 100 senior drivers between 60 and 86 years (80 healthy volunteers and 20 with specific vision deficits) using Rasch modeling. Second, we compared the outcome of the gestalt decision made by trained professionals with that based on weighted error scores from the standardized assessment. Rasch analysis provided good evidence for construct validity and inter-rater reliability of the on-road assessment and some evidence for internal reliability. Goodness of fit statistics for all items were within an acceptable range and the item hierarchy was logical. The test had a moderate reliability index (0.67). The best cut off score yielded sensitivity of 81% and specificity of 95% compared with the gestalt decision. Further research is required with less competent drivers to more fully examine reliability. Healthy senior drivers failed to check blind spots when changing lanes and made errors when asked to report road markings and traffic signs as they drove. In addition unsafe drivers had difficulty negotiating intersections and lane changes.     

基于ADAMS的FSAE赛车建模与操纵稳定性仿真

为建立某FSAE赛车的虚拟样机模型及评价其操纵稳定性,采用机械系统动力学分析软件ADAMS中的ADAMS/CAR模块,建立了某中国大学生方程式(FSAE)赛车模型,并介绍了建模的过程及要点.建立了比赛赛道的模型,利用ADAMS/CHASSIS得到赛车在此赛道上的最佳行驶路径.利用Smart driver模块仿真得到赛车...     

Predicting at-fault car accidents of older drivers

Considerable research shows car accidents are difficult to predict using screening tests. The objective of this exploratory study is to determine whether detailed accident analysis taking into account the specific accident type might enhance the predictive power of a standardised road test and a set of selected neuropsychological tests. Moreover, this study addresses the validity and reliability of performance-based driving evaluation. The sample consisted of 84 older drivers between 65 and 96 years of age who were referred for a fitness-to-drive evaluation. Using discriminant analyses, the subjects were classified as drivers with and without at-fault accidents. We compared the accuracy of neuropsychological tests and a road test for postdicting all accidents, accidents classified into two categories and accidents classified into four different categories. The percentages of correctly classified subject were highest at the level of the most detailed classification. These results suggest that, although accident prediction is difficult, the predictability of car accidents by neurocognitive measurements and a road test increases when the kind of accident is specified.     

Quantifying the role of risk-taking behaviour in causation of serious road crash-related injury

This study was designed to quantify the increased risk of road crash-related injury, which can be attributed to risk-taking behaviour. A case-control study was conducted to compare motor vehicle drivers (car and bike) who had been hospitalised for injuries following crashes with population-based controls. Cases were recruited prospectively over 12 months and controls were randomly selected from license holders (car and bike) living in the same geographical location as cases. A self-administered questionnaire was used to ascertain participants' driving behaviour, general risk-taking behaviour and selected demographic characteristics. After adjusting for demographic variables, number of years of driving and total distance driven per week, logistic regression analysis showed that a high risk acceptance was associated with an eight-fold increased risk of having a crash that resulted in serious injury (OR 7.8, 95% CI 4.2-15.8). The findings of this study support the suggestion that certain host factors increase the risk of crash-related serious injury. There would appear to be a reasonable argument for persisting with injury prevention programmes, which concentrate on host as well as environment risk factor reduction.     

动力系统悬置传递特性分析与应用

车辆行驶时,各结构运动件的振动相互影响,合理判断结构彼此影响的关系,是分析悬置隔振特性的前提。分析和总结以加速度为激励计算的传递特性规律,推导车辆实际运行时悬置传递特性,结合试验设计悬置件隔振特性计算流程,以独立动力系统激励试验、独立路面激励试验、实际稳态车速试验获得振源间的干涉成分、共频成分和相应比例;最后,通过实车试验测试与数据处理,获得动力系统悬置时域隔振特性。提出的方法能够有效地提高悬置隔振率和传递特性的评价精度,具有一定工程应用价值。     

客运专线轨道不平顺功率谱分析

轨道不平顺是车辆振动的主要激扰源,也是限制列车最高运行速度的主要因素之一,直接关系到列车运行的平稳性、安全性和舒适性。文章以秦沈客运专线轨检车实测轨道不平顺数据为统计样本,基于样本平稳性检验,采用FFT方法进行样本空间的谱估计,并由MATLAB编程得到轨道不平顺谱密度。基于轨道不平顺样本的总体平均,得出了谱密度频率平滑曲线和谱密度曲线拟合表达式,并与我国重载提速干线的谱密度曲线进行了对比分析。在此基础上,对秦沈客运专线的轨道状态进行了评估。     

Motorcycling experience and hazard perception

Studies of hazard perception skills in car drivers suggest that the ability to spot hazards improves with driving experience. Is this the case with motorcyclists? Sixty-one motorcyclists, split across three groups (novice, experienced and advanced riders) were tested on a hazard perception test containing video clips filmed from the perspective of a motorcyclist. Response times to hazards revealed that the advanced riders (who had completed an advanced riding course) were the fastest, and the experienced riders were the slowest to respond to hazards, with novice riders falling in-between. Advanced riders were also found to make more internal attributions regarding the causes of the hazards than novice riders (though on a general measure of Locus of Control there was no difference between groups). The results demonstrate a link between advanced training and motorcycling hazard perception skill, but raise important concerns about the effects of mere experience on rider safety. This challenges previous conceptions that simply extrapolated from our understanding of the hazard perception skills of car drivers to this particularly vulnerable group of road users.     

Effect of consecutive driving on accident risk: A comparison between passenger and freight train driving

This study combined driver-responsible accidents with on-board driving hours to examine the effect of consecutive driving on the accident risk of train operations. The data collected from the Taiwan Railway Administration for the period 1996–2006 was used to compute accident rates for varied accumulated driving hours for passenger and freight trains. The results showed that accident risk grew with increased consecutive driving hours for both passenger and freight trains, and doubled that of the first hour after four consecutive hours of driving. Additional accident risk was found for freight trains during the first hour due to required shunting in the marshalling yards where there are complex track layouts and semi-automatic traffic controls. Also, accident risk for train driving increased more quickly over consecutive driving hours than for automobile driving, and accumulated fatigue caused by high working pressure and monotony of the working environment are considered to be the part of the reason. To prevent human errors accidents, enhancing safety equipment, driver training programs, and establishing a sound auditing system are suggested and discussed.     

Effects of higher-order driving skill training on young, inexperienced drivers' on-road driving performance

The aim of the current study was to compare the effects of training in higher-order driving skills (e.g., perceptual, motivational, insight) and vehicle handling skill training in relation to on-road driving performance, hazard perception, attitudes to risky driving and driver confidence levels in young, inexperienced drivers. Thirty-six young drivers (23 males and 13 females, average age 16.3 years), mostly on a restricted NZ driver licence, participated in a Driver Training Research camp. Participants were randomly allocated to one of three equally sized groups according to the type of driving skill training (5 days) they received: higher-order, vehicle handling or control (no training). Professional driver assessors conducted a comprehensive driving assessment before (Baseline) and after the training (Post Training). At both time points, participants also carried out a computerised hazard perception task, and completed self-report questionnaires to assess attitudes to risky driving and driver confidence. In terms of on road driving, the participants who received higher-order driving skill training showed a statistically significant improvement in relation to visual search and the composite driving measure. This was accompanied by an improvement in hazard perception, safer attitudes to close following and to dangerous overtaking and a decrease in driving related confidence. The participants who received vehicle handling skill training showed significant improvements in relation to their on-road direction control, speed choice and the composite driving score. However, this group showed no improvement in hazard perception, attitudes to risky driving or driver confidence. The findings will be discussed in the context of driver training as a viable crash prevention intervention in regard to young, inexperienced drivers.