Effects of field of view on lateral control performance in a vision-based autonomous vehicle

This paper addresses the effects of field of view on lateral control performance in a vision-based autonomous vehicle with simulation studies. When a vehicle drives around a circle with the lateral control algorithm proposed here, the performance is evaluated for a tracking error and ride quality for locations and sizes of the field of view. The results show that a field of view covering from 10 to 30 m in front of a vehicle is the optimal with respect to both the error and the ride quality, and it is independent of the vehicle speed.     

Speed ratio control of a parallel layout double cavity half-toroidal CVT for four-wheel drive

A double cavity half-toroidal CVT has two variators, which gives a hint of a new four-wheel drive without a center differential gear unit by applying each of them to drive front and rear drive shafts independently. Torque re-circulation at cornering or different tire radii between front and rear tire is avoided by compensating the speed ratio of variator. The controller adjusts the attitude angle of power roller of the front variator against the rear by measuring the steering angle at cornering. This paper describes the speed ratio control system of the 4WD-CVT with speed ratio range of 1 : 8.7 and test results of vehicle motion mounted on a 3.2L RV.     

Road characteristics and environment factors associated with motorcycle fatal crashes in Malaysia

This study aims to determine risk factors contributing to traffic crashes in 9,176 fatal cases involving motorcycle in Malaysia between 2010 and 2012. For this purpose, both multinomial and mixed models of motorcycle fatal crash outcome based on the number of vehicle involved are estimated. The corresponding model predicts the probability of three fatal crash outcomes: motorcycle single-vehicle fatal crash, motorcycle fatal crash involving another vehicle and motorcycle fatal crash involving two or more vehicles. Several road characteristic and environmental factors are considered including type of road in the hierarchy, location, road geometry, posted speed limit, road marking type, lighting, time of day and weather conditions during the fatal crash. The estimation results suggest that curve road sections, no road marking, smooth, rut and corrugation of road surface and wee hours, i.e. between 00.00 am to 6 am, increase the probability of motorcycle single-vehicle fatal crashes. As for the motorcycle fatal crashes involving multiple vehicles, factors such as expressway, primary and secondary roads, speed limit more than 70 km/h, roads with non-permissible marking, i.e. double lane line and daylight condition are found to cause an increase the probability of their occurrence. The estimation results also suggest that time of day (between 7 pm to 12 pm) has an increasing impact on the probability of motorcycle single-vehicle fatal crashes and motorcycle fatal crashes involving two or more vehicles. Whilst the multinomial logit model was found as more parsimonious, the mixed logit model is likely to capture the unobserved heterogeneity in fatal motorcycle crashes based on the number of vehicles involved due to the underreporting data with two random effect parameters including 70 km/h speed limit and double lane line road marking.     

The high-expansion-ratio gasoline engine for the hybrid passenger car

A 50% reduction in CO₂ and fuel consumption has been achieved by the Toyota Hybrid System, which has been in mass production since 1997. This is achieved by the combination of two permanent magnet motors and a newly developed gasoline engine that is optimized in terms of its displacement and heat cycle. Delaying the closing timing of the intake valves effectively separates the compression ratio and expansion ratio, so that the expansion ratio, which is normally set from 9 : 1 to 10 : 1 to suppress knocking, can be set to 13.5 : 1. This new engine shows better than 230 g/kWh BSFC over a wide operating range. Motor-assisted quick start, improved catalyst warm-up, and the elimination of light-load firing allow the system to achieve very clean emissions levels.     

Development of a time-to-digital converter IC for laser radar

A CMOS time-to-digital converter IC with half-nanosecond resolution by inverter-delay-time has been developed for measuring time intervals with a fully digital circuit. A new circuit “ring-gate-delay” system using two revolution counters can make the area of the circuit far smaller than it would be without them. Accuracy is assured through digital processing with a 2 MHz crystal clock reference. A time resolution of 0.5 ns and a measurement range of 0–2200 ns using 1.5 μm CMOS were confirmed.     

The new 1.3-liter 2-plug engine for the 2002 Honda Fit

A new 1.3 l engine developed for the 2002 model Honda “Fit” achieves high fuel economy (23 km/l in the Japanese 10.15 mode) and more than 50% emissions reduction from the 2000 standards in Japan. This engine has dual spark plugs that are located in a diagonal position in order to conduct the flame closely, and which control the ignition sequentially to burn rapidly. In addition, new technology of shot peening with MoS₂ reduced mechanical friction and a six-hole injector and oblique structuring converter reduced its emissions.     

Gasification and dry distillation of automobile shredder residue (ASR)

A variety of energy recovery technologies are being developed for recovering usable materials from automobile shredder residue (ASR), considering combustible gases and protecting the environment. We measured the pyrolysis characteristics of ASR in a gasification, dry distillation process. For efficiently recovering thermal energy, we determined that a heating value of the evolved gas of about 15.5 MJ/kg (3700 kcal/kg) can be achieved at a pyrolysis temperature greater than 500°C. We also determined that pyrolysis temperatures must be maintained below 700°C to prevent forming significant levels of oxidized copper in the ASR residue. In this paper we describe such a dry distillation system and operating conditions to achieve efficient operation.     

Combustion characteristics of a direct-injection stratified charge S.I. engine

A direct-injection stratified charge gasoline engine has been developed that can run on an air–fuel ratio of 40–50 : 1. Major characteristics of the engine system include swirl gas flow and fuel injection in a swirl spray at a maximum fuel pressure of 10 MPa. Another notable feature is that the intake port configuration is virtually identical to that of a conventional engine, allowing flexibility for shared use of components among different engines. This new engine achieves better fuel economy, lower cold-start HC emissions and higher power output than conventional multipoint injection engines.     

Knocking detection using wavelet instantaneous correlation method

In this study, we propose a new method for knocking detection that utilizes the vibration signal measured by a knock sensor under the knocking conditions known as a real mother wavelet (RMW), and carry out instantaneous correlation from the wavelet transform. We call this method the wavelet instantaneous correlation (WIC) method. The degree of similarity between the RMW and the vibration of the engine block was judged and only the knocking signal from the vibration of the engine block was extracted. The results obtained here show that the method proposed in this study is useful for knocking detection even if the engine speed is very high at 6000 rpm.     

780 N/mm2 grade hot-rolled high-strength steel sheet for automotive suspension system

590 N/mm²-grade high-strength hot-rolled steel sheet has been applied to an automotive suspension system, and 780 N/mm²-grade has recently been applied on trial to the same parts. Both of the steels used for the suspension system are required to have good formability, especially high stretch-flangeability. This paper describes the effect of the microstructure of the steel on stretch-flangeability. The results of mill trials have shown that the bainitic-ferrite mono-phase microstructure has the best mechanical properties.     

Do driver training programs reduce crashes and traffic violations? — A critical examination of the literature

This paper reviews the evaluation literature on the effectiveness of classroom and behind-the-wheel driver training. The primary focus is on North America programs as originally taught in high schools but now also by private instructors. Studies from the United Kingdom, Australia, New Zealand and Scandinavia are also included.By far the most rigorous study to date was the experimental study in DeKalb, Georgia, U.S.A. This study used a randomized design including a control group and a very large sample size to provide reasonable statistical precision. I reexamine the DeKalb data in detail and conclude that the study did show evidence of small short-term crash and violation reductions per licensed driver. However, when the accelerated licensure caused by the training is allowed to influence the crash and violation counts, there is evidence of a net increase in crashes.The other studies reviewed present a mixed picture but the better designed quasi-experimental evaluations usually showed no effects on crash rates but almost all suffer from inadequate sample size. I show that as many as 35,000 drivers would be required in a two group design to reliably detect a 10% reduction in crash rates.The advent of GDL laws in North America and other countries has largely remedied the concern over accelerated licensure of high risk teenage drivers by delaying the progress to full licensure. Conventional driver training programs in the U.S. (30 h classroom and 6 h on-the-road) probably reduce per licensed driver crash rates by as little as 5% over the first 6–12 months of driving. The possibility of an effect closer to 0 cannot be dismissed.Some GDLs contain an incentive for applicants to complete an advanced driver training program in return for shortening the provisional period of the GDL. The results of Canadian studies indicate that any effects of the driver training component are not sufficient to offset the increase in accidents due to increased exposure.There is no evidence or reason to believe that merely lengthening the number of hours on the road will increase effectiveness. Programs directed toward attitude change and risk taking better address the underlying cause of the elevated crash risk of young drivers but these behaviors are notoriously resistant to modification in young people.     

车用柴油机的二级增压

阐述了重型车用柴油机及轿车柴油机上采用的二级可变增压系统原理。试验表明，在柴油机上应用二级增压能有效提高升功率、增大低速扭矩、改善加速性、改善低速油耗及排放。指出，二级增压系统存在着较为复杂的系统构成、体积和质量都较大及有关控制难以实现等问题，并探讨了其解决方案。     

重载车爬坡下的公路临界坡长确定

山区公路纵坡坡度和坡长组合设置存在不合理,导致重载车辆爬坡速度下降过快,而诱发长大纵坡路段交通事故。在分析车辆爬坡过程中的受力情况及运行特征的基础上,以某重载汽车为例使用仿真软件建立动力学模型。在约束最大爬坡性能的前提下,对满载时重载车辆爬坡特性及车速衰减规律进行仿真。在车辆功率重量比一定的前提下,设计不同坡度下的重载车爬坡及不同入坡车速的重载车爬坡2种工况,研究车辆爬坡过程中速度衰减规律及入坡车速和纵坡坡度对爬坡稳定车速的影响。车速衰减曲线表明,入坡车速对爬坡稳定车速没有影响,但其与稳定坡长成正比。对于爬坡性能差的重载车辆,当入坡车速为80 km/h 时,临界坡长小于400 m;当入坡车速为60 km/h 时,临界坡长小于300 m,均低于《公路工程技术标准》的相关规定。因此,爬坡过程中当车速衰减超过20 km/h时,需设置爬坡车道。最后,结合仿真中合理坡度和坡长的组合,提出具体的爬坡车道设置方法。      

Recycling technology of tire rubber

Material recycling technology for automotive tire rubber waste was developed by the continuous devulcanization method. The deodorization during the recycling process has become possible by the newly developed method. The devulcanized rubber obtained by these methods from tire rubber waste, generated from both the manufacturing products and scrap tires, shows excellent mechanical properties applicable to the new tire rubber compounds in engineering practice. Furthermore, it was confirmed by actual road tests that a test truck tire containing 10 wt % of the devulcanized rubber in the tread might exhibit tread wear behavior almost equal to that for the standard type with the new rubber compound.     

Magneto-rheological suspensions for improving ground vehicle’s ride comfort,stability, and handling

ABSTRACT

A state-of-the-art discussion on the applications of magneto-rheological (MR) suspensions for improving ride comfort, handling, and stability in ground vehicles is discussed for both road and rail applications. A historical perspective on the discovery and engineering development of MR fluids is presented, followed by some of the common methods for modelling their non-Newtonian behaviour. The common modes of the MR fluids are discussed, along with the application of the fluid in valve mode for ground vehicles’ dampers (or shock absorbers). The applications span across nearly all road vehicles, including automobiles, trains, semi-trucks, motorcycles, and even bicycles. For each type of vehicle, the results of some of the past studies is presented briefly, with reference to the originating study. It is discussed that Past experimental and modelling studies have indicated that MR suspensions provide clear advantages for ground vehicles that far surpasses the performance of passive suspension. For rail vehicles, the primary advantage is in terms of increasing the speed at which the onset of hunting occurs, whereas for road vehicles – mainly automobiles – the performance improvements are in terms of a better balance between vehicle ride, handling, and stability. To further elaborate on this point, a single-suspension model is used to develop an index-based approach for studying the compromise that is offered by vehicle suspensions, using the H₂ optimisation approach. Evaluating three indices based on the sprung-mass acceleration, suspension rattlespace, and tyre deflection, it is clearly demonstrated that MR suspensions significantly improve road vehicle’s ride comfort, stability, and handling in comparison with passive suspensions. For rail vehicles, the simulation results indicate that using MR suspensions with an on-off switching control can increase the speed at which the on-set of hunting occurs by as much as 50% to more than 300%.     

Heavy-duty vehicle modelling and longitudinal control

This paper addresses modelling, longitudinal control design and implementation for heavy-duty vehicles (HDVs). The challenging problems here are: (a) an HDV is mass dominant with low power to mass ratio; (b) They possess large actuator delay and actuator saturation. To reduce model mismatch, it is necessary to obtain a nonlinear model which is as simple as the control design method can handle and as complicated as necessary to capture the intrinsic vehicle dynamics. A second order nonlinear vehicle body dynamical model is adopted, which is feedback linearizable. Beside the vehicle dynamics, other main dynamical components along the power-train and drive-train are also modelled, which include turbocharged diesel engine, torque converter, transmission, transmission retarder, pneumatic brake and tyre. The braking system is the most challenging part for control design, which contains three parts: Jake (engine compression) brake, air brake and transmission retarder. The modelling for each is provided. The use of engine braking effect is new complementary to Jake (compression) brake for longitudinal control, which is united with Jake brake in modelling. The control structure can be divided into upper level and lower level. Upper level control uses sliding mode control to generate the desired torque from the desired vehicle acceleration. Lower level control is divided into two branches: (a) engine control: from positive desired torque to desired fuel rate (engine control) using a static engine mapping which basically captures the intrinsic dynamic performance of the turbo-charged diesel engine; (b) brake control: from desired negative torque to generate Jake brake cylinder number to be activated and ON/OFF time periods, applied pneumatic brake pressure and applied voltage of transmission retarder. Test results are also reported.     

重型汽车低附着路面制动稳定性的仿真研究

文章利用trucksim重型汽车动力学仿真软件,对六轮双轴重型汽车在低附着路面左右车轮附着系数不一致情况下进行紧急制动的行驶工况进行了仿真研究。研究结果表明在低附着路面进行紧急制动时,对制动轮进行制动压力控制,有ABS控制的重型汽车比没有ABS控制的重型汽车具有更好地行驶稳定性。但在低附着路面上,有ABS控制的重型汽车比没有ABS控制的重型汽车的制动距离增加了很多,这对重型汽车的行车安全性非常不利。