Simulated Road Research Articles

Looking and thinking when driving: The impact of gaze and cognitive load on steering

Driving around bends at high speeds is a task performed by many on a daily basis but the underlying mechanisms of steering control remain largely unknown. Previous research has shown that when steering, gaze direction can be a critical component of success. However, with increased use of in-vehicle information systems (IVIS), there is growing competition over the same resources that are needed to steer (gaze as well as associated attentional resources). Although it can be argued that locomotor steering is an automatic task that can be performed without recourse to conscious “cognitive” control, much simpler locomotor-related tasks, such as judging one’s heading, have been shown to be affected by concurrent attentional tasks (Wann, Swapp, & Rushton, 2000). Here we examined whether an attentional task placed at an offset fixation point influenced concurrent steering performance along a computer simulated road. The experiments either used gaze-fixation points that had similar properties to real-world road signs (i.e. moved relative to the vehicle) or were more akin to IVIS (i.e. fixed to the vehicle). Results showed that gaze fixation eccentric to future path caused systematic steering biases. The degree or type of cognitive load did not change the degree of steering bias, but there was some evidence of decreased lane variability when viewing the IVIS-type displays. No differences in steering performance were found between the different types of cognitive task. We conclude that where you look is critical for safe driving, and IVIS-type displays might make drivers more susceptible to cognitive interference.

Comparative Effects of Simulated and Conventional Transportations on the Thyroid Response of Stallions (Equus caballus)

This study compares the circulating total (T3 and T4) and free (fT3 and fT4) iodothyronine levels in horses subjected to simulated and conventional road transportations. Eighteen healthy Sanfratellano stallions were used. Three different durations were compared (1, 2, and 3 hours) in both situations. Blood samples were collected 1 week before the experimental treatment, at rest in baseline conditions, at 09:00, 10:00, 11:00, and 12:00 AM; before loading and after 1, 2, and 3 hours of simulated transport, immediately after unloading; and 3 weeks later before loading and after transport of 50, 150, and 250 km, after unloading. Results showed higher T3 values after 150 km (P = .0314) and 250 km (P = .0497) and higher T4 values after 50 (P = .0138), 150 (P = .0169), and 250 km (P = .0013) after conventional than simulated road transportation. From the obtained data, it is seems that total and free iodothyronines may be useful in assessing short-term transportation stress in horses.

Experimental methodology for assessing the environmental fate of organic chemicals in polymer matrices using column leaching studies and OECD 308 water/sediment systems: Application to tire and road wear particles

Automobile tires require functional rubber additives including curing agents and antioxidants, which are potentially environmentally available from tire and road wear particles (TRWP) deposited in soil and sediment. A novel methodology was employed to evaluate the environmental fate of three commonly-used tire chemicals (N-cyclohexylbenzothiazole-2-sulfenamide (CBS), N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine (6-PPD) and 1,3-diphenylguanidine (DPG)), using a road simulator, an artificial weathering chamber, column leaching tests, and OECD 308 sediment/water incubator studies. Environmental release factors were quantified for curing (fC), tire wear (fW), terrestrial weathering (fS), leaching from TRWP (fL), and environmental availability from TRWP (fA) by liquid chromatography–tandem mass spectroscopy (LC/MS/MS) analyses. Cumulative fractions representing total environmental availability (FT) and release to water (FR) were calculated for the tire chemicals and 13 transformation products. FT for CBS, DPG and 6-PPD inclusive of transformation products for an accelerated terrestrial aging time in soil of 0.1years was 0.08, 0.1, and 0.06, respectively (equivalent to 6 to 10% of formulated mass). In contrast, a wider range of 5.5×10−4 (6-PPD) to 0.06 (CBS) was observed for FR at an accelerated age of 0.1years, reflecting the importance of hydrophobicity and solubility for determining the release to the water phase. Significant differences (p<0.05) in the weathering factor, fS, were observed when chemicals were categorized by boiling point or hydrolysis rate constant. A significant difference in the leaching factor, fL, and environmental availability factor, fA, was also observed when chemicals were categorized by log Kow. Our methodology should be useful for lifecycle analysis of other functional polymer chemicals.

Active Control of Structure-Borne Road Noise Based on the Separation of Front and Rear Structural Road Noise Related Dynamics

Axle forces from tire-road interaction can excite different structural resonances of the vehicle hence a high number of sensors is required for observing and separating all the vibrations dynamics that are coherent with the cabin noise. Feed-forward road noise control strategies adopted so far rely mainly on capturing these dynamics and thus the number of sensors constitutes one major limitation of this approach. Therefore there is a necessity for reducing the number of sensors without degrading the performance of an ANC system. In the past coherence function analysis has been found to be a useful tool for optimizing the sensor location. In this case coherence function mapping was performed between an array of vibration sensors and the headrest microphones in order to identify the locations on the structure that are highly correlated with road noise bands in the compartment. A vehicle with an advanced suspension system was used for applying the method and defining some locations as reference signals for feed-forward active road noise control. Three different real-time control experiments were performed with structure-borne road noise simulated by applying broad band random forces to tires through shaker transducers. A single reference feed-forward adaptive controller evaluated the signals from each sensor location with simulated road noise excitation applied to: front wheels only, rear wheels only and whole vehicle. This way it is demonstrated that the control can be focused at specific road noise bands with a low number of sensors.

4-Post Road Simulator 를 이용한 농용 트랙터의 유연 다물체 동역학 해석

Abstract : Agricultural tractors are utilized on rough road such as rice paddy field. Therefore, static and dynamic load should be considered when simulating structural analysis with finite element analysis (FEA). But it consumes a lot of time and effort to measure dynamic load because of difficulty and complexity in modeling various field working load conditions and kinematics of machinery. In this paper, to reduce the efforts, 4-post road simulator is developed for agricultural tractor like modeling commercial vehicle. In proving ground test in our facility, I measured acceleration of front/rare axle and strain of body frame to validate input loads. The acceleration is used for defining input loads. And strain is validated with dynamics analysis including mode superposition method. As a result, I was able to calculate 4-post input road profiles, which represent similar proving ground profile with good reliability. † Corresponding Author, jspark@lsmtron.com Ⓒ 2015 The Korean Society of Mechanical Engineers

A CFD Study of Roadside Barrier Impact on the Dispersion of Road Air Pollution

This study evaluated road shape and roadside barrier impact on near-road air pollution dispersion using FLUENT computational fluid dynamics (CFD) model. Simulated road shapes are three types, namely atgrade, depressed, and filled road. The realizable k-e model in FLUENT CFD code was used to simulate the flow and dispersion around road. The selected concentration profile results were compared with the wind tunnel experiments. The overall concentration profile results show good agreement with the wind tunnel results. The results showed that noise barriers, which positioned around the at-grade road, decrease the horizontal impact distance (In this study, the impact distance was defined as the distance from road surface origin coordinate to the position whose mass fraction is 0.1.) lower 0.33~0.65 times and change the vertical air pollution impact distance larger 2.0~ 2.27 times than those of no barrier case. In case of filled road, noise barriers decrease the horizontal impact distance lower 0.24~0.65 times and change the vertical air pollution impact distance larger 3.33~3.55 times than those of no barrier case. The depressed road increase 1.53~1.68 times the vertical air pollution impact distance. It contributes the decrease of horizontal air pollution impact distance 0.32~0.60 times compare with no barrier case.

Research on Spectrum Development Methodology for Vehicle Indoor Road Simulation Test

Research on Spectrum Development Methodology for Vehicle Indoor Road Simulation Test

Development of a UDDS-Comparable Framework for the Assessment of Connected and Automated Vehicle Fuel Saving Techniques

Since the mid-seventies, the trend toward the development and adoption of fuel-efficient light-duty vehicles has become well established. As part of this trend, many complex strategies for powertrain efficiency have been evaluated and successfully marketed in the form of electric and hybrid electric vehicles (EVs and HEVs), among others. More recently, interest in connected and automated vehicle (CAV) eco-driving strategies as a means to reduce fuel consumption has increased. Despite these trends, assessments of even the simplest eco-driving concepts against existing vehicle powertrain measurement techniques have been hampered by the lack of a unified comparative baseline, owing to the disparity between each technologys approach. On the one hand, powertrain engineering focuses on the efficient response to a controlled driving profile, while on the other hand, eco-driving focuses on modifying the driving profile itself as a means to efficiency. In an effort to resolve this disconnect, the authors present the development of a simplified methodology for ensuring that eco-driving scenarios are contextualized against traditional drive-cycle based text techniques, in this case, the Urban Dynamometer Driving Schedule (UDDS). To accomplish this, a simulated road network is developed such that normal, non-automated driving results in a good approximation to the UDDS. The simulation environment is then used to demonstrate the fuel savings possible by the application of a representative eco-driving technique in a way that maintains context with traditional drive-cycle based fuel saving technologies. Using this technique, researchers will be able to directly compare the fuel savings of CAV and established powertrain technologies.

Prepositioning of driving simulator motion systems

Motion base driving simulators have limited space in which to recreate the motions of the simulated road vehicle. Conventional motion cueing algorithms strive to centre the cabin in the simulator motion envelope to accommodate accelerations in a worst case scenario while respecting the physical boundaries. Using information about the road ahead one can preposition the cabin to an off-centre point, virtually increasing the available space so that larger motions are made possible. The prepositioning algorithm presented here was developed as an addition to a classical motion cueing algorithm and makes use of road data and vehicle speed to adjust the simulator displacement. Simulations show that the amount of acceleration presented by an x, y-sled system can, with prepositioning, be increased by up to 25% in longitudinal and 53% in lateral direction for an example road. A comparative study including 12 test subjects indicates that the perceived realism is rated higher with prepositioning.

Developing Vision-based and Cooperative Vehicular Embedded Systems for Enhancing Road Monitoring Services

This paper presents a generic processing architecture as well as tools and approaches for supporting road monitoring services. More precisely, a small-scale simulator is presented for experimenting the design and the implementation of vision-based vehicular embedded systems in indoor environments, i.e. a test bench for embedded system laboratories. This simulator employs embedded electronic systems, sensors as well as hybrid communication and computational technologies. In particular, these technologies are exploited in order to produce our cooperative and real-time embedded system for enhancing road monitoring services. This type of simulator can be used for developing a variety of innovative road monitoring services based on the detection of dynamical points of interest. Notably, a system has been implemented in the case of a simulated road service to aid police agency for the recognition of wanted individuals and stolen vehicles. Experimental results show the potential of the simulator for fostering the development of a next generation of vehicular embedded system as well as for the emergence of participatory road services.

How to combine different microsimulation tools to assess the environmental impacts of road traffic? Lessons and directions

In the last decades, traffic microsimulation platforms have a growing complexity allowing a detailed description of vehicle traffic dynamics in a second-by-second basis. However, to project spatially their outputs, some precautions must be followed. Therefore, we analyze some variables used in the microscopic traffic models which have a high impact on further applications, especially when a spatial projection is required. To assess these objectives, a microsimulation framework which includes traffic and emission models was defined to characterize traffic flows and to evaluate vehicular emissions. This general methodology was then applied in a European medium sized city using two scenarios: (i) considering a Lagrangian approach and (ii) using an Eulerian approach of the simulation road traffic platform. The Lagrangian approach shows that if we have long links (some hundred meters, e.g. >500m), we lose the spatial detail on emissions. On the other hand, using the Eulerian approach to define very small links (some few meters, e.g. <30m), a significant statistic representation of traffic dynamics, in that link, was not obtained, particularly in areas with low traffic flow. The latter situation can occur because the vehicle speed can be high enough that did not allow recording any information in that link, even considering a high time resolution analysis (second-by-second). Thus, a non-linear trend of the error is identified when such data are analyzed geographically. Accordingly, depending on the use of those microsimulation tools, we identify some best practices related with the traffic model design that must be followed to minimize those errors.

Start-Up Time and Walking Speed in Older Adults Under Loaded Conditions During Simulated Road Crossing

Background/Study Context: The safety of older pedestrians in road crossing has received considerable attention but previous studies measure gait characteristics only under unloaded conditions. The aim of this study was to investigate the start-up time and walking speed under loaded conditions that reflect daily activities of older adults in Singapore.Methods: Thirty-two older adults (age (SD) = 69.4 (7.0) years) and 20 young controls (age (SD) = 23.1 (2.0) years) walked under four conditions: (1) unloaded, (2) pushing a stroller loaded with 10 kg, (3) pulling a shopping cart loaded with 15 kg, and (4) carrying two shopping bags each loaded with 2 kg. Start-up time was determined from video recordings and walking speed measured using timing gates. A mixed-model analysis of variance (ANOVA; age by walking condition) with repeated measures was applied.Results: Start-up times were slower in the stroller and shopping cart conditions compared with the unloaded and shopping bags conditions. Loading reduced walking speed, with the shopping cart being the slowest, followed by the stroller and then the shopping bags. A significant interaction was found, with young controls reducing their speeds more substantially while handling the stroller/cart than older participants.Conclusion: Loading caused a compromise in start-up time and walking speed. The start-up time was slower when pushing a stroller or pulling a shopping cart but remained unaffected by carrying shopping bags. Speed was reduced under all loaded conditions, with a greater effect in young than older participants when handling a stroller or shopping cart.

Vehicle Parameter Identification for Vertical Dynamics

In this paper, a nonlinear full car model considering the nonlinear and hysteretic characteristics of the shock absorber is developed. An approach to integrate the hybrid shock absorber model into the vehicle model using system identification techniques is then presented. To validate the approach, parameter identification of the nominal linear full car model and parameter identification of the full car model with nonlinear/hysteresis shock absorber force input are compared. The target vehicle is tested on an MTS Systems Corporation tire-coupled 4-post road simulator and the experimental data validate the system identification methods proposed in this paper.

Simulation Study on ESP Fuzzy Control Based on Road Automatic Identification

ESP (Electronic Stability Program) is a kind of active safety device which can comprehensively improve the brake, drive and high speed performance of the automobile. Mastering the key technologies of ESP control system plays an important role in improving the performance of ESP. Vehicle dynamic model and engine model with 9 degrees of freedom of one passenger car were established based on vehicle and tire force analysis. The ESP fuzzy control model based on slip ratio control was established. The optimal slip ratio under different pavements was confirmed by using road recognition method. ESP fuzzy control was realized under MATLAB/Simulink environment. And through the split road simulation prove the validity of the road recognition algorithm, and the effectiveness of the fuzzy control strategy. The simulation and the debugging results indicate that the ESP fuzzy control strategy based on road automatic identification works well, and obviously improves automobile stability under critical situations. And all of these make a good foundation for the further research and development for the ESP integrated control system.

Design and Test Development of a Comprehensive Performance Test Bench for Electric Wheel

In order to research the driving performance of electric vehicle driven by the electric wheels and provide the test basis to the design of electric vehicle, the author of the paper designed and developed a multifunctional comprehensive performance test bench for electric wheel. Such test bench has the basic functions of road simulation, resistance simulation, vehicle weight simulation and inertia simulation, and the other functions of steering simulation, coupling simulation of electric braking and mechanical coupling, wheel hub motor performance test lamp. The author of the paper made certain design for the relevant test items, which has far-reaching significance for the test and research of the battery electric vehicle (BEV) driven by the wheel hub motor.

Research on New Automotive Drum Bench and Control System

Automobile drum test bench is conducted test car's dynamic economy tests, special test equipment emissions performance evaluation and analysis of the simulated vehicle right road resistance is the key to drum test rig. This paper first describes the electrical simulation theory cars with resistance and inertia, and the establishment of automobile roads resistance electrical simulation mathematical model of the software platform drum bench and control system is analyzed and designed and conducted inertia simulation control mode the test results showed that inertia simulation control and reliable operation.

Models of dynamic load coefficient for a two–axle truck obtained from road simulator data

This paper presents the results of analyses of measurements of dynamic tyre forces generated by a two–axle truck with leaf spring suspension in experiments conducted on a hydraulic actuation system (road simulator). The road simulator, called DYNmAC, has four actuators equipped with load scales to measure dynamic forces applied by the truck wheels. The dynamic tyre forces are characterised by a Dynamic Load Coefficient (DLC) defined as the ratio of standard deviation over mean tyre force. The test variables were: tyre type (standard radial dual, low–profile dual, and wide–base super single tyre), tyre inflation pressure, vehicle speed, wheel static load, and road roughness. The DLC values obtained for the two dual tyres were very similar for all combinations of test variables. The wide–base tyre produced DLC's 10 to 12 percent lower than each of the dual tyres. Linear regression models were developed for each of the three tyre types, relating DLC to tyre inflation pressure, vehicle speed, wheel static load, and road roughness. One hundred and forty–four (144) data points were used in deriving each model. The effects of the test variables on DLC were similar for all tyres. Based on the regression results, the test variables can be ranked in terms of their effect on DLC as follows: vehicle speed (strongest effect), road roughness, wheel static load, and tyre inflation pressure (weakest effect). The pavement damage potential of the three types of tyres was evaluated using Eisenmann's road stress factor. The results indicate that the wide–base tyre is likely to cause pavement damage twice as large as each of the dual tyres.

Road Roughness Measurement and Analysis for Vehicle Bench Test

Road roughness, the most direct automotive input, is a kind of basic data. Its analysis and applications have important effects on vehicle performance. Several methods such as wavelet analysis, amplitude-domain analysis, frequency-domain analysis are used to analyze the road elevation series of a highway. Through some disposal of the original survey data, a series of representative data has been taken to reproduction test in a 4-poster road simulator. Both analyses and test results show that, the proposed methods can be used for the actual data process of road roughness and in the vehicle bench test.

Configuring retroreflective markings to enhance the night-time conspicuity of road workers

This study investigated whether the night-time conspicuity of road workers can be enhanced by positioning retroreflective strips on the moveable joints in patterns that convey varying degrees of biological motion. Participants were 24 visually normal adults (12 young M=26.8 years; 12 older M=72.9 years). Visual acuity, contrast sensitivity and glare sensitivity were recorded for each participant. Experimenters acting as road workers walked in place on a closed road circuit within simulated road work sites, facing either the oncoming driver or the roadway (presenting sideways to the driver) and wearing one of four clothing conditions: (i) standard road worker vest; (ii) standard vest plus thigh-mounted retroreflective strips; (iii) standard vest plus retroreflective strips on ankles and knees; (iv) standard vest plus retroreflective strips positioned on the extremities in a configuration that conveyed biological motion (“biomotion”). As they drove along the closed road participants were instructed to press a button to indicate when they first recognized that a road worker was present. The results demonstrated that regardless of the direction of walking, road workers wearing biomotion clothing were recognized at significantly (p<0.05) longer distances (3×), relative to the standard vest alone. Response distances were significantly shorter for the older drivers. Contrast sensitivity was a better predictor of the ability to recognize road workers than was visual acuity or glare sensitivity. We conclude that adding retroreflective strips in the biomotion configuration can significantly improve road worker conspicuity regardless of the road worker's orientation and the age of the driver.

Management and Optimization of Road Design Process Based on Multi Agent Simulation

Aiming at the urgent requirement and characteristics of the road design process, this paper presents multi agent simulation approach to manage and optimize road design process effectively. Tasks decompose and management model for road design process based on multi agent were studied firstly. Road design process modeling and simulation based on multi agent were realized next. By the simulation, further optimization analysis to improve the road design process was carried out by rearranging tasks flow and organization structure. A real road design process was simulated, and the results showed the simulation evaluation indexes could effectively reflect the process performance.