Browse Topic: Roads and highways

Items (411)
Find
Speed Limiter Using Disturbance Observer2021-01-01024/6/2021
This paper suggests disturbance observer which improves performance of speed limit assist control. The nonlinear disturbance observer was designed so that disturbance caused by parameter and load uncertainties is able to be estimated exponentially. With the contribution of the observer, feed-forward and integral controllers can be omitted while improving steady-state error elimination and overshoot reduction. The acceleration observer is also designed to reduce the effect of wheel slip and changing slope. The performance of the controllers has been verified not only on flat roads, but also on wave road and rapidly changing ramps.
Son, Huiun, Jo, Kyuhwan, Kim, Sangjoon, Cho, Jinkyeom, Jeon, Sungbae
A Real-Time Curb Detection Method for Vehicle by Using a 3D-LiDAR Sensor2021-01-00764/6/2021
Effectively detecting road boundaries in real time is critical to the applications of autonomous vehicles, such as vehicle localization, path planning and environmental understanding. To precisely extract the road boundaries from the 3D-LiDAR data, a dedicated algorithm consisting of four steps is proposed in this paper. The steps are as follows: Firstly, the 3D-LiDAR data is pre-processed by employing the RANSAC method, the ground points are quickly separated from the original 3D-LiDAR point cloud to reduce the disturbance from the obstacles on the road, this greatly decreases the size of the point cloud to be processed. Secondly, based on the principle of 3D-LiDAR scanning, the ground points are divided into scan layers. And the road boundary points of each scan layer are detected by using three spatial features based on sliding window. Thirdly, based on the improved beam model, the road type (straight road or curved road) where the vehicle is located is predicted, and then the edge points are subdivided into different areas by the road type. Finally, we use the distance filtering and RANSAC filtering to filter out false road boundary points caused by obstacles and obtain accurate road boundaries. Compared to other methods, we can effectively reduce the wrong classification of road edge points caused by obstacles by using the improved beam model. And the false points caused by obstacles are effectively reduced by using distance filtering and RANSAC filtering. The performance of the proposed method is verified through experiments with a vehicle driving on campus roads and extensive tests with the KITTI data set the experimental results demonstrate the accuracy and robustness of the proposed method.
Du, Zhiqiang, Wu, Jian, He, Rui, Wang, Guojun, Li, Shuai, Zhang, Jinghua, Chen, Guosheng
Rethinking the Way We Move Beyond COVID-19WP-00126/11/2020
As the world grapples to combat the spread of COVID-19, our city streets have nearly emptied. Unprecedented community mitigation interventions have been applied in efforts to “flatten the curve” and slow the transmission of the virus. Social distancing measures have dramatically altered our daily behavior; notably, in the ways we do or do not move. This report seeks to identify emerging trends in urban mobility and road safety in respect to COVID-19. This is followed by a discussion of how we could shape our mobility future as communities begin to reopen.
Chang, Annie, Miranda-Moreno, Luis
Updating the Grade Severity Rating System (GSRS) for Wyoming Mountain Passes: A Description of Tests and Results02-13-01-00055/13/2020
Truck crashes on Wyoming mountain passes due to brake heating has been a long-standing issue due to the steep downgrades that characterize some routes in the state. The grade severity rating system (GSRS) developed by the Federal Highway Administration (FHWA) to recommend maximum safe speeds has been identified as a viable countermeasure to reducing the incidence of downgrade truck crashes. However, several decades have passed since the GSRS was developed. In the decades since its development, truck features have undergone radical changes in terms of design. The streamlined design of tractors and trailers, use of drag reduction devices, changes in engine features, and adoption of radial tires have led to a reduction in the non-brake forces that retard motion. Truck brakes have also changed along with retarder characteristics. This has meant that maximum safe speeds recommended by the GSRS have been conservative. This article discusses tests and results involved in updating the GSRS. Maximum safe speeds from the updated GSRS model was compared to the previous FHWA model and was found to be higher while allowing for faster descent. The effect of the GSRS on retarder use was also evaluated using the updated model. The updated GSRS model should increase driver confidence in recommended speeds while improving Wyoming mountain pass safety.
Moomen, Milhan, Ksaibati, Khaled
Iterative Dynamic Programming Based Model Predictive Control of Energy Efficient Cruising for Electric Vehicle with Terrain Preview2020-01-01324/14/2020
As a global optimization method, dynamic programming (DP) can be employed to seek the optimal velocity with minimum energy consumption for EV on given driving cycles. Due to its terrible computational burden, conventional DP is not suitable for real-time implementation especially with higher dimensions. In this paper, we propose an iterative dynamic programming (IDP) approach to reduce computing time firstly. The IDP can obtain the optimal control laws alike the conventional DP by converging the optimal control strategy iteratively and save considerable computing time. Second, the developed IDP and model predictive control (MPC) are combined to establish a real-time cruising controller called IDP-MPC for an EV with terrain preview. In the predictive controller, we use the IDP to solve a constrained finite horizon nonlinear optimization problem. Finally, to assess the performance of the proposed cruising controller, simulation on a realistic urban expressway road terrain is implemented. Energy-saving potential of the IDP-MPC controller is explored by comparing to DP and constant speed (CS) cruising controllers. The comparative study indicates that the IDP-MPC controller can obtain near-optimal energy-saving capacity compared to DP controller.
Ju, Fei, Zhuang, Weichao, Wang, Liangmo, Wang, Qun
What If the Speed Had Been Less? Causation in Time Limited and Distance Limited Hazards2020-01-08814/14/2020
With a path intrusion incident, it is almost always the case that the collision would have been avoided if the pedestrian had not run out, or if the vehicle on the minor road had stopped, or so on. However should the other party be thought to have been travelling at an excessive speed, often the reconstructionist is asked to make a calculation of what whether the collision would, at some alternative speed say equal to the speed limit, still have occurred. In that way causation is addressed. The paper distinguishes between those hazards which are distance limited and those which are time limited, giving definitions of the two types. Distance limited hazards are deterministic, but time limited hazards have a probabilistic basis. This difference has important implications for causation. For a hazard at a fixed distance, there is a well known formula for calculating whether the collision would have been avoided at a slower alternative speed. However a time limited hazard often has no clear cut boundary between avoided/not avoided. According to the warning time during which the hazard develops, the alternative speed of the vehicle may mean that a collision would certainly be avoided, the alternative speed may have no effect, or the effect of the alternative speed may be in between. A method is given for estimating the effect of a slower speed. A further type of path intrusion is where the pedestrian, or driver on a minor road, has seen the oncoming vehicle but gauged that there was time to cross in front of it. This also is considered, with its implications for causation. Traffic lights, where one must not go over on red, have similarities and differences with path intrusion incidents. The paper gives a formula for the maximum speed at which a traffic light might be approached if drivers made the best choices, with a discussion of the difference between the unrealistic result of this calculation and a realistic maximum.
Searle, John
Theoretical Development of Localized Pseudo Damage06-13-01-00032/18/2020
Damage is accumulated by vehicles as they travel. Current damage methods allow for the total accumulated damage to be identified; however, they do not allow for identification of the road segments that induce the largest component of the damage. The objective of this article is to develop a measure, Localized Pseudo Damage (LPD), which defines the amount of damage each individual road excitation contributes to the total accumulated pseudo damage. A novel theoretical development of LPD along with analytical and discrete simulation analyses is presented. The results show that the LPD is causal and correctly identifies the location and magnitude of damaging events. This is further demonstrated with the application of the method on a real road surface.
Altmann, Craig, Ferris, John
The Road to the Top is Not on the Map Personal JournalR-5032/10/2020
The Road to the Top is Not on the Map Personal Journal is designed to accompany the best-selling book by Carla Bailo and Terry Barclay. While enjoying The Road to the Top is Not on the Map, readers can capture their own thoughts, ideas and feelings in this journal. Thoughtful writing prompts helps users clarify the habits, motivations, triumphs, defeats, and lessons learned throughout their career. To further enhance the experience of The Road to the Top is Not on the Map, the journal includes guidelines for starting a book club with discussion questions.
Bailo, Carla, Barclay, Terry
Unsettled Impacts of Integrating Automated Electric Vehicles into a Mobility-as-a-Service Ecosystem and Effects on Traditional Transportation and Ownership 1235 1999EPR201900412/20/2019
This is London editing to see how removing all formatting works in this rich text editor: USA The current business model of the automotive industry is based on individual car ownership, yet new ridesharing companies such as Uber and Lyft are well capitalized to invest in: Large, commercially operated, on-demand mobility service vehicle fleets. Bribes for government officials Insane robots! cyborgs demented roombas H2O and e=mc2 Car manufacturers like Tesla want to incorporate personal car owners into part-time fleet operation by utilizing the company’s fleet service. These robotaxi fleets can be operated profitably when the technology works in a reliable manner and regulators allow driverless operation. Although Mobility-as-a-Service (MaaS) models of private and commercial vehicle fleets can complement public transportation models, they may contribute to lower public transportation ridership and thus higher subsidies per ride. This can lead to inefficiencies in the utilization of existing public transportation infrastructure. MaaS platforms can also cause a reduced reliance on parking infrastructure (e.g., street parking lanes and parking garages) which can contribute to an improvement in overall traffic flow, and a reduction in capital investment for commercial and residential real-estate development. Urban planning can be better centered around the true mobility needs of the citizens without sacrificing valuable space for vehicles that are inactive most of the time. A key challenge is the transition phase where traditional forms of car ownership and transportation coexist with new forms of mobility services (before true MaaS platforms are fully optimized). Another fundamental issue is determining the true cost of car ownership and establishing ideal cost structures for on-demand mobility services in order to replace the need of owning a car. This needs to occur without compromising subsidized public transportation which provides affordable transportation for low-income groups. NOTE: SAE EDGE™ Research Reports are intended to identify and illuminate key issues in emerging, but still unsettled, technologies of interest to the mobility industry. The goal of SAE EDGE™ Research Reports is to stimulate discussion and work in the hope of promoting and speeding resolution of identified issues. SAE EDGE™ Research Reports are not intended to resolve the issues they identify or close any topic to further scrutiny. Click here to access the full SAE EDGETM Research Report portfolio. [It appears that the text needs highlighted to select it, which is good. This will prevent accidentally removing all formatting with a stray click.] [It appears that the underline and color change of the hyperlink remains, though it is no longer a hyperlink.] [If TM is a symbol and not a superscript, it is unchanged, which is good.] For reference, the original formatting: USA The current business model of the automotive industry is based on individual car ownership, yet new ridesharing companies such as Uber and Lyft are well capitalized to invest in: Large, commercially operated, on-demand mobility service vehicle fleets. Bribes for government officials Insane robots! cyborgs demented roombas H2O and e=mc2 Car manufacturers like Tesla want to incorporate personal car owners into part-time fleet operation by utilizing the company’s fleet service. These robotaxi fleets can be operated profitably when the technology works in a reliable manner and regulators allow driverless operation. Although Mobility-as-a-Service (MaaS) models of private and commercial vehicle fleets can complement public transportation models, they may contribute to lower public transportation ridership and thus higher subsidies per ride. This can lead to inefficiencies in the utilization of existing public transportation infrastructure. MaaS platforms can also cause a reduced reliance on parking infrastructure (e.g., street parking lanes and parking garages) which can contribute to an improvement in overall traffic flow, and a reduction in capital investment for commercial and residential real-estate development. Urban planning can be better centered around the true mobility needs of the citizens without sacrificing valuable space for vehicles that are inactive most of the time. A key challenge is the transition phase where traditional forms of car ownership and transportation coexist with new forms of mobility services (before true MaaS platforms are fully optimized). Another fundamental issue is determining the true cost of car ownership and establishing ideal cost structures for on-demand mobility services in order to replace the need of owning a car. This needs to occur without compromising subsidized public transportation which provides affordable transportation for low-income groups. NOTE: SAE EDGE™ Research Reports are intended to identify and illuminate key issues in emerging, but still unsettled, technologies of interest to the mobility industry. The goal of SAE EDGE™ Research Reports is to stimulate discussion and work in the hope of promoting and speeding resolution of identified issues. SAE EDGE™ Research Reports are not intended to resolve the issues they identify or close any topic to further scrutiny. Click here to access the full SAE EDGETM Research Report portfolio.
Acoustic Effects of Lightweighting in a Sport Utility Vehicle2019-01-15066/5/2019
Weight reduction is a significant concern for automotive manufacturers, and is often achieved by removing as much mass as is safe from the structure of the vehicle. This has a negative effect on the interior acoustics, which has become more and more of an issue as technology has advanced and people expect to be able to do business and consume media in their vehicles. Traditional acoustic treatment tends to be very heavy, which eliminates some of the weight savings. Recently a vehicle study was performed to determine if the current production sound package in a highly-rated sport utility vehicle could be maintained or improved while reducing the weight. This paper presents the results of that study. The study focused on road noise transmitted through the floor (carpet, rear wheelhouse inner and trunk insulation) and engine noise transmitted through the dash (dash inner). Testing was performed both at the vehicle level on the road and at the component level in the laboratory. It was found that the lightweight sound package was highly effective against road noise, but less effective against engine noise. Additional evaluation was performed to determine if underbody treatment would improve the performance, and it was found the addition of absorption to the underbody of the car helps with road noise, but less so with engine noise. Ultimately, the lightweight parts, working together as a system, provided sound absorption in the frequency range of interest while still providing the necessary sound transmission loss along the noise paths.
Frey, Andrea Lynne
Structure-Borne Prediction on a Tire-Suspension Assembly Using Experimental Invariant Spindle Forces2019-01-15416/5/2019
Road induced noise is getting more and more significant in context of the electrification of the powertrain. The automotive industry is seeking for technologies to predict the contribution of vehicle components upfront, early in the development process. Classical Transfer Path Analysis (TPA) is a well-established technique that successfully identifies the transmission paths of noise and vibration from different excitation sources to the target responses. But it has a drawback: it requires the physical availability of the full vehicle. To achieve shorter development cycles, to avoid costly time-consuming design iterations and due to the limited availability of prototypes, engineers derived a method that addresses these requirements. Component-based TPA is a relatively new structure borne substructuring approach that allows to characterize the source excitation by a set of equivalent loads (blocked forces) independently from the receiver structure and to predict its behavior when coupled to different receivers. Frequency Based Substructuring, FBS, is applied in order to obtain the coupled assembly. However, there are a number of challenges affecting its applicability, such as the proper modelling of the coupling degrees of freedom and the difficulty to access the interface connection points. Geometrical reduction aims to solve those inconveniences. This paper aims to investigate these challenges of component-based TPA by measurements on a tire-wheel suspension in static condition. The source component (the tire-wheel) is characterized by a set of blocked forces and transfer functions identified on a dedicated tire-wheel test-rig. These calculated loads are combined with the FRFs of the fully assembled system. The FRFs are calculated by using experimental substructuring methods. The sensitivity of applying FBS together with geometrical reduction in the frame of component-based TPA will be analyzed.
Ortega Almirón, Jesús, Bianciardi, Fabio, Corbeels, Patrick
Assessment of Automotive Environmental Noise on Mobile Phone Hands-Free Call Quality2019-01-15976/5/2019
Environmental noises such as wind, road, powertrain, and HVAC noise are important aspects to consider when implementing a hands-free terminal for mobile phone calling from within a car. Traditionally, these environmental noises have been exclusively considered for driver comfort; however, with the introduction of the hands-free terminals (HFT) and increasing consumer demand relative to mobile phone call quality, a broader implication of high background noise levels should be considered. HFT algorithm development and implementation can and does provide a high level of background noise suppression to mitigate these concerns, but this is often done at the expense of computational power and cumulative delay during a phone call. The more advantageous solution would be to address the problem from a source and path perspective with emphasis on reduction of noise in the frequency bands which most influence call quality performance. The assessments shown throughout this paper establish a sensitivity of HFT call quality to background noise levels based on industry-standard metrics, including those defined by International Telecommunication Union (ITU) standards. These assessments were established based on a series of experiments that include characterizing vehicle to vehicle variability with a common background noise and single vehicle sensitivity to reductions in background noise. In the background noise sensitivity investigations, filtering investigations were conducted to identify the frequency ranges which drive the most significant degradation in speech intelligibility and HFT performance. The information gained provides insight regarding the requirements for mitigating background noise in the context of both customer comfort as well as HFT performance, both of which are key factors in the perception of overall vehicle quality.
Pruetz, Jeffrey, Watson, Channing, Tousignant, Todd, Govindswamy, Kiran
A Novel Vision-Based Framework for Real-Time Lane Detection and Tracking2019-01-06904/2/2019
Lane detection is one of the most important part in ADAS because various modules (i.e., LKAS, LDWS, etc.) need robust and precise lane position for ego vehicle and traffic participants localization to plan an optimal routine or make proper driving decisions. While most of the lane detection approaches heavily depend on tedious pre-processing and great amount of assumptions to get reasonable result, the robustness and efficiency are deteriorated. To address this problem, a novel framework is proposed in this paper to realize robust and real-time lane detection. This framework consists of two branches, where canny edge detection and Progressive Probabilistic Hough Transform (PPHT) are introduced in the first branch for efficient detection. To eliminate the dependency of the framework on assumptions such as flatten road, deep learning based encoder-decoder detection branch, which leverages the powerful nonlinear approximation ability of CNN, is introduced to improve the robustness and contribute to a precise intermediate result. Since the detection rate of the CNN branch is much slower than the feature-based branch, a coordinating unit is designed. The two branches also backup each other so that the system can be failure-tolerant. Finally, Kalman filter is applied for lane tracking. Experiment result shows that the proposed framework can achieve robust detection result under various driving scenario with more than 100 FPS. A closed-loop lane keeping simulation is also carried out, which shows the precise and robust detection result from proposed framework can greatly contribute to the lane keeping performance.
Yang, Shun, Wu, Jian, Shan, Yanhu, Yu, Yinan, Zhang, Sumin
Comprehensive Study on Crashes with Pedestrians on Indian Roads2019-26-00041/9/2019
Pedestrian crashes are a major safety concern worldwide, especially in India. About one of every ten traffic-related fatalities in the country is a pedestrian. In 2016 nearly 15,800 pedestrians were killed in India. They were mainly exposed to risk when crossing and walking on the road in urban and rural areas. The aim of the study was to understand the pedestrian behavior on the road and to identify characteristics of pedestrian crashes in India. Many unique behavior was observed like pedestrian crossed half way and stopped in middle of road. Nearly 10% of pedestrians are fatal each year involving in ~5% of overall accidents in India, This study revels every second pedestrian accident occurred while walking and crossing the road straight. An attempt made to evaluate benefit of in vehicle pedestrian safety systems, as an example Car-AEB (Advance Emergency Braking) pedestrian is selected as one of the available technologies and systematic methodology is derived in order to evaluate the benefit of this product.
Kumaresh, Girikumar, Joerg, Moennich, Lich, Thomas
Nano-Additives Increase the Service Life of ConcreteTBMG-3321011/1/2018
A new method increases the service life of concrete structures by reducing the infiltration rates of deleterious ions. The key is a nano-sized additive that slows down penetration of chloride and sulfate ions from road salt, seawater, and soils into the concrete.
Evaluation of the Powertrain Condition Based on the Car Acceleration and Coasting Data2018-01-17719/10/2018
Diagnosis of the car is a necessary means for early detection of developing malfunctions. A technique for diagnosing on a short road based on the acceleration in the second and third gears and coasting from 50 or 40 to 20 km/h is proposed. The results should be compared with the reference values calculated, taking into consideration the speed rolling resistance dependence, described by the square trinomial, the speed air resistance dependence with the variable exponent, the losses of the transmission idling mode and the progressive total resistances decrease at speeds below 25 km/h. The general speed dependence of the total resistance is described by a sixth-degree polynomial but not the second-degree one, as many researchers believe. The experimental check was performed on a subcompact sedan with 1.6 atmo engine. Weight of 1370 kg. First class road with an average rise of 0.0182, asphalt in good condition. There was no wind. Measuring and recording equipment: GPS receiver Magellan Triton 300, digital cameras Canon, an anemometer. The processing of video recordings was carried out in the Virtual Dub and MS Excel programs. The evaluation based on the acceleration and coasting times showed the engine technical condition better than the nominal one. According to the records of the II, III and IV gear’s torque curves were restored. The curves are far from the nominal steady-state curve, but are close to the chassis dynamometer curve. The reached torque value exceeds the maximum passport one by 5-10 Nm. So, the on-road diagnostics with simple equipment provides true information, suitable both for the vehicle condition assessing and for research.
Rabinovich, Ernest, Gritsuk, Igor V., Zuiev, Vladimir, Zenkin E.Y., Evgeny, Golovan, Andrii, Zybtsev, Yuriy, Volkov, Vladimir, Gerlici, Juraj, Kravchenko, Kateryna, Volska, Olena, Rudnichenko, Nickolay
Performance Margin for Geometric Road Design06-11-04-00228/8/2018
Although several methods exist for measuring the performance capability of a vehicle, many require detailed knowledge of the forces acting at each tire contact patch or do not account for both the vehicle dynamics and the road geometry. A simple vehicle model is proposed to estimate the upper limit of performance capability for a given operating condition (the Performance Envelope) based on the Effective Friction and the road geometry (slope and cross-slope). The Effective Friction accounts for both the vehicle dynamics and road surface properties and is estimated, through simulation or experimentation, using two standard vehicle dynamics tests: constant radius cornering and straight-line braking. The Performance Margin is defined as the additional performance capability available before the vehicle reaches the Performance Envelope, both represented in the intuitive units of gravity. The Performance Margin is applicable to both geometric road design and vehicle control; both of which are crucial as transportation agencies and vehicle manufacturers prepare for the introduction of autonomous vehicles.
Kang, Yong-suk, Ferris, John B.
Taking It to the Streets: Designing Streetlamp Optical ComponentsTBMG-297407/1/2018
The task of creating a streetlamp optical system has changed over the last 20 years and due to this change, so has optical design software. Let’s compare the task of designing optical street lamp components 20 years ago with the process today.
The Unique Dynamic and Structural Solution of a Finite Element Representation of Full Vehicle Based on the Integrated Implicit/Explicit Approach2018-01-12144/3/2018
This article describes a numerical methodology, based on Finite Element approach, able to simulate, with a unique solution, the dynamic and structural response of a full vehicle running on fatigue reference roads. The current durability process is a multidisciplinary one based on a combination of three different phases: load definition, stress definition, and fatigue life prediction. For Long-Time Histories events, the second phase of this process is necessarily based on a Linear assumption using a Static or Dynamic approach. However, in durability events, some situations can lead the material to work in the plastic range, thus putting on the top the strength aspect of the performances and making these phases not independent and sequential, but strongly interdependent. The goal of the methodology reported in this article is to merge, in a unique numerical simulation, the load and stress definition phases. To this purpose, the solution of a full vehicle model of a commercial van, with a complete Finite Element representation of the body structure, running on fatigue roads, is investigated. This work represents an evolution of current load generation methodology and is able to quantify the impact of Nonlinear effects, such as contact and material plastic behavior, on structural response. A comparison of loads and stresses evaluated with the old approach and the new one is performed.
Duni, Efthimio, Signorini, Alberto, Puleo, Vincenzo, SIAS, Alessandro, Piccardi, Simone, Mennillo, Serena
Simulation Research of a Hydraulic Interconnected Suspension Based on a Hydraulic Energy Regenerative Shock Absorber2018-01-05824/3/2018
The current paper proposes a hydraulic interconnected suspension system (HIS) based on a hydraulic energy-regenerative shock absorber (HESA) comparatively with the passive suspensions. The structure and working principles of the HIS system are introduced in order to investigate the damping performance and energy regeneration characteristics of the proposed system. Then, the dynamic characteristics of the HIS-HESA system have been investigated based on a 4-DOF longitudinal half vehicle model. In the simulation, two different road inputs were used in the dynamic characterization of the HIS-HESA; the warp sinusoidal excitation, and the random road signal. In addition, a comparative analysis was provided for the dynamic responses of the half vehicle model for both the HIS-HESA and the conventional suspension. Furthermore, a parametric analysis of the HIS-HESA has been carried out highlining the key parameters that have a remarkable effect on the HIS-HESA performance. The dynamic performance evaluation includes both of the body acceleration and the pitch angle as the main analysis criteria of the vehicle dynamic performance. The results showed that the vehicle with the HIS-HESA system has good anti-pitch performance and excellent ride performance against the traditional suspensions. Moreover, the HIS-HESA suspension system can regenerate some of the dissipated power due to the damping process.
Zou, Junyi, Guo, Xuexun, Xu, Lin, Abdelkareem, Mohamed A. A., Gong, Bian, Zhang, Jie, Tan, Gangfeng
A New Strategy to Optimize the Economy Performance of the New Power-Split Hybrid Transmission Platform CHS-HT28002018-01-10164/3/2018
CORUN CHS has recently developed a new power-split hybrid transmission platform CHS-HT2800, which has added 2 clutches compared to CHS-HT1800. With involvement of 2 E-motors CHS-HT2800 has 9 forward gears, including 3 electric forward gears and 6 hybrid forward gears. Among the 6 hybrid gears 4 gears are fixed-ratio gears and the remaining 2 gears are eCVT gears. This paper describes a strategy, designed for CHS-HT2800, how to select the optimal mode, the optimal gear and the optimal work point of the engine to achieve the best economy performance in the real traffic. Because it is universally accepted, that the WLTC cycle can represent real world vehicle operation on urban and extra-urban roads, motorways, and freeways. The introduced strategy will be validated with the help of the WLTC cycle.
Gao, Ji, Zhang, Tong, Yu, Haisheng, Wang, Chen, Cheng, Huijun, Ge, Fuxiang
Energy-Harvesting Potential and Vehicle Dynamics Conflict Analysis under Harmonic and Random Road Excitations2018-01-05684/3/2018
Energy has the worldwide concern since the World War. Recently, the energy harvesting technology has got more attraction in different fields and applications. Hence, in a world where energy becomes rare and expensive, even the small quantities are worth to be harvested where it can be exploited in different applications. Vehicle suspension is one of the vibration power dissipation sources in which the undesired vibration is dissipated into heat waste. Accordingly, the principal motivation of this study is exploitation the conflict between the potentially harvested power and vehicle dynamics in automotive suspension system induced by road irregularity. Therefore, in terms of RMS conflict diagrams, the conflict between the potential power and vehicle dynamics are sufficiently and comprehensively defined considering a vehicle speed of 20 m/s. The conflict analysis includes ride comfort (body acceleration), road handling (dynamic tire force) and potentially harvested power considering the influence of sprung and unsprung masses, stiffness rate, damping coefficient, tire stiffness, speed and road roughness. In this manner, a quarter suspension mathematical model is developed and built in Matlab/Simulink interface and uneven road profile is modeled for different road classes according to the ISO standard. Besides, a parametric analysis study is adopted to investigate the influence of the model parameters on the potentially harvested power. Then, the amount of the potential harvested power is quantified and presented for different driving conditions. The results are of interest for the researchers and vehicle manufacturers for further considerations during design and test preparation in the generative vehicle suspensions.
Abdelkareem, Mohamed A. A., Xu, Lin, Zou, Junyi, Ali, Mohamed Kamal Ahmed, Essa, F. A., Elagouz, Ahmed, Hassan, Mohamed A.
Road Loads for Durability Analysis using Virtual Iterations2018-01-05674/3/2018
Durability assessment for suspension systems and vehicle structures requires loads on each component from different road profiles. If a new vehicle is to be assessed for durability early in the design phase, a prototype must be built and tested on proving grounds. This can be time consuming and expensive. A large number of design configurations are considered for designing new vehicles in the truck industry. However, the number of prototypes that can be built and tested will be limited. The only options would be to depend on generic load cases or to use a virtual method that can translate limited measurements to various configurations. Roush CAE has successfully implemented a method called virtual iterations to back calculate the road profiles from the CAE model of a vehicle that has been tested on the desired road tracks. This paper presents the various steps involved in the virtual iterations process, the full vehicle model setup and the most important parameters which affect the output. The underlying assumptions and their influence on the application of the final tire patch displacements to the new vehicle design are discussed. An example problem is presented and correlated results are shown for various continuous vibration events like resonance roads, cobblestones as well as impact events like curb impact and chuckholes.
Vemuri, Achyut, Talekar, Nitin, Avutapalli, Bhaskar
Road Classification Based on System Response with Consideration of Tire Enveloping2018-01-05504/3/2018
This paper presents a road classifier based on the system response with consideration of the tire enveloping. The aim is to provide an easily applicable yet accurate road classification approach for automotive engineers. For this purpose, tire enveloping effect is firstly modeled based on the flexible roller contact (FRC) theory, then transfer functions between road input and commonly used suspension responses i.e. the sprung mass acceleration, unsprung mass acceleration, and rattle space, are calculated for a quarter vehicle model. The influence of parameter variations, vehicle velocity, and measurement noise on transfer functions are comprehensively analyzed to derive the most suitable system response thereafter. In addition, this paper proposes a vehicle speed correction mechanism to further improve the classification accuracy under complex driving conditions. A random forest based classifier is finally trained by treating center spatial frequencies of the octave bands as the classifier input as per ISO-8608. Simulation results validate the proposed approach for various road levels with various velocities, and the overall classification accuracy improved from F-score of 0.7547 (without velocity correction) to F-score of 0.9807 (with velocity correction).
Qin, Yechen, Yuan, Kang, Huang, Yanjun, Tang, Xiaolin, Wang, Zhenfeng, Dong, Mingming
Study on Test Scenarios of Environment Perception System under Rear-End Collision Risk2018-01-10794/3/2018
The foundation of both advanced driving assistance system(ADAS) and automated driving (AD) is an accurate environment perception system(EPS). However, evaluation and test method of EPS are seldom studied. In this paper, naturalistic driving environment was studied and test scenarios for EPS under rear-end collision risk were proposed accordingly. To describe driving environment, a new concept named environment perception element(EPE) was first proposed in this paper, which refers to all the objects that the EPS must perceive during driving. Typical environment perception elements include weather and light conditions, road features, road markings, traffic signs, traffic lights, other vehicles, pedal cyclists and pedestrians and others. Driving behaviors collected in Shanghai, China were classified and rear-end collision risk scenarios were obtained and described using EPEs. Probability distribution of EPEs was therefore obtained. Afterwards, the correlation between EPEs and risk level of scenarios (evaluated by maximum longitudinal deceleration) were revealed by means of Fisher’s Exact Test. Based on these two characteristics of driving environment, typical test scenarios for EPS were established with the help of cluster analysis, and the test scenarios were simulated in Prescan. These test scenarios were generally consistent with the probability distribution of EPEs, making the test results reliable. Results from this paper fill the gap between the high demand of dynamic and representative EPS test scenarios and the existing static picture database used in development and validation of EPS and are of great significance to the development of ADAS and AD in China.
Liu, Lin, Zhu, Xichan, Ma, Zhixiong
A Lane-Changing Decision-Making Method for Intelligent Vehicle Based on Acceleration Field2018-01-05994/3/2018
Taking full advantage of available traffic environment information, making control decisions, and then planning trajectory systematically under structured roads conditions is a critical part of intelligent vehicle. In this article, a lane-changing decision-making method for intelligent vehicle is proposed based on acceleration field. Firstly, an acceleration field related to relative velocity and relative distance was built based on the analysis of braking process, and acceleration was taken as an indicator of safety evaluation. Then, a lane-changing decision method was set up with acceleration field while considering driver’s habits, traffic efficiency and safety. Furthermore, velocity regulation was also introduced in the lane-changing decision method to make it more flexible. Afterwards, the polynomial trajectory planning method was matched up with this lane-changing decision-making method and simulations based on Matlab/Simulink were finally conducted to verify the method presented in this article. As the simulation results showed, adopting the lane-changing decision-making method based on acceleration field, the lane-changing measurements such as starting position, span and driving speed can be optimized with driver’s habits involved. At the same time, the vehicle safety can be well ensured.
Zhu, Bing, Liu, Shuai, Zhao, Jian
Further Validation of Equations for Motorcycle Lean on a Curve2018-01-05294/3/2018
Previous studies have reported and validated equations for calculating the lean angle required for a motorcycle and rider to traverse a curved path at a particular speed. In 2015, Carter, Rose, and Pentecost reported physical testing with motorcycles traversing curved paths on an oval track on a pre-marked range in a relatively level parking lot. Several trends emerged in this study. First, while theoretical lean angle equations prescribe a single lean angle for a given lateral acceleration, there was considerable scatter in the real-world lean angles employed by motorcyclists for any given lateral acceleration level. Second, the actual lean angle was nearly always greater than the theoretical lean angle. This prior study was limited in that it only examined the motorcycle lean angle at the apex of the curves. The research reported here extends the previous study by examining the accuracy of the lean angle formulas throughout the curves. The degree to which these equations can be used to model the development of lean as the rider enters a curve is evaluated. The prior study was also limited in that it only examined maneuvers on an oval track in a flat parking lot. The current study examines the accuracy of the theoretical lean angle formulas on a mountainous highway with curves of varying radius and changing banking and slope. The real-world data presented in this study are also utilized in conjunction with the lean angle formula to examine the interplay between the geometry of a curve, the motorcycle speed, and the rider’s skill level.
Rose, Nathan A., Carter, Neal, Smith, Connor
PROACTIVE METHODS FOR ROAD SAFETY ANALYSISWP-000510/12/2017
To date, the universal metric for road safety has been historical crash data, specifically, crash frequency and severity, which are direct measures of safety. However, there are well-recognized shortcomings of the crash-based approach; its greatest drawback being that it is reactive and requires long observational periods. Surrogate measures of safety, which encompass measures of safety that do not rely on crash data, have been proposed as a proactive approach to road safety analysis. This white paper provides an overview of the concept and evolution of surrogate measures of safety, as well as the emerging and future methods and measures. This is followed by the identification of the standards needs in this discipline as well as the scope of SAE’s Surrogate Measures of Safety Committee.
Chang, Annie, Saunier, Nicolas, Laureshyn, Aliaksei
Problems in Assessing Pneumatic Wheel Unbalance of a Passenger Car Determined with Test Road in Normal Conditions2017-01-18056/5/2017
The vibrations of the sprung mass of a passenger car, traveling along a road surface, are random. They also form its main source but there are besides other factors to consider. The resulting force ratio is overlapped by other phenomena occurring at the interface of the pneumatic tire with the road surface, such as non-uniformity of tires, shape deformations and imbalances. The resulting additional inertia force acts on the kinematic force that was previously induced on the car body. The vibrations of the sprung mass of the car body at the time can be considered as a potential source of diagnostic information, but getting insight their direct identification is difficult. Moreover, the basic identification is complicated because of the forces induced due to the random interference from road roughness. In such a case, the ratio defined as SNR assumes negative values. Due to the lack of comprehensive studies involving identification of the unbalance of the whole pneumatic wheel in real conditions, these authors decided to undertake experimental research in this area. The main objective of the study was to identify the unbalance of a pneumatic wheel based on the vibration of the sprung mass in a car body. The registered acceleration sensor signal was analyzed in the frequency domain, thus obtaining information about its specific components such as the value of the amplitude and frequency range prevailing in its spectrum. The analysis of the recorded signals applied selected statistical methods (autocorrelation, probability density distribution), as well as the frequency domain (PSD, FFT, STFT). To this purpose, this paper presents the results of both bench and road implemented at selected speeds ranging from 50 to 100 km / h. The results of the study were compared with the results of simulation calculations using the model of quarter car. The application process was based on a one-dimensional Bayes classifier and a designated distribution function for the strengthening of a classifier representing the state of the road surface.
Prażnowski, Krzysztof, Mamala, Jaroslaw
The Analysis of the Stiffness-Damping Parameters of a H-Bahn Vehicle2017-01-18906/5/2017
H-Bahn ("hanging railway") refers to the suspended, unmanned urban railway transportation system. Through the reasonable platform layout, H-Bahn can be easily integrated into the existing urban transit system. With the development of urban roads, the associated rail facilities can be conveniently disassembled, moved and expanded. The track beam, circuits, communication equipment, and sound insulation screen are all installed in a box-type track beam so that the system can achieve a high level of integration and intelligence. The carriage of the modern H-banh vehicle is connected with the bogies by two hanging devices. The vehicle is always running in the box-type track beam; therefore there are less possibilities of derailment. Consequently, the key work focuses on the running stability evaluation and curve negotiation performance analysis. In order to study the factors affecting running stability, the different stiffness and damping parameters in the primary and secondary suspension system are assigned to calculate the running stability index. To begin with, the vertical and lateral mathematic -dynamics models of the vehicle are established. Moreover, based on the USA VI rail spectrum, the vertical and lateral input displacements of the rail can be developed. In addition, the time-domain acceleration responses calculated by the dynamics model are converted to the amplitude-frequency characteristic curves by the Fourier transform. Finally, the weighted Sperling index calculated by the corresponding frequency and amplitude can evaluate the vehicle running stability. From the results of the vertical running stability analysis, the vertical indexes Wz are less than 2.5 almost, so that the running stability belongs to Level 1. For analyzing the lateral vibration, the hanging device is regarded as a fixed rigid body connecting the vehicle body and bogies. From the results of lateral running stability analysis, the lateral index Wy increases with the lateral stiffness of the air spring (< 2.5 × 105), and Wy is more than 3.0 at some points. In order to analyze the curve negotiation performance, the statics model describing the lateral rolling condition is established. By solving the nonlinear equations describing the statics model, the rolling angles of vehicle body are calculated in different conditions. The stiffness of air spring and centrifugal acceleration should be controlled in the limited values for improving the curve negotiation performance.
Zhang, Xingyu, Yang, Bo, Zhang, Manchuang, Hu, Sanbao
Active Safety Concept to Mitigate Slippery Road Conditions2017-01-50025/30/2017
Antilock braking systems (ABS) are inherently limited by the static coefficient of friction (µ) between a vehicle’s tires and the road surface. This paper explores a unique active safety concept, Integrated Coefficient Enhancement (ICE), which works to improve ABS well beyond their present limits. The ICE concept was developed using a basic physics principle: to change µ between two surfaces, at least one of the surfaces must be altered in some way. By quickly deploying a specially designed tractive medium (TM) to aid in directional stability and braking, hazardous situations can be greatly mitigated. This paper describes the features and testing results of this TM and its aerodynamic-mechanical-electronic deployment apparatus. Under all slippery road conditions tested, the developed TM mitigated skidding, with improvements that ranged from 20% to several hundred percent, depending on conditions and deployment rates.
Skarie, James Bradley
Lane Detection Using Orientation of Gradient and Vehicle Network Signals2017-01-00423/28/2017
The continuous growth of market for Advanced Driver Assistance Systems based on image processing features leads to the advance of the applied techniques, increasing thus the driving safety. Mostly of the edge detection algorithms are traditional approaches, and to achieve improvements it is necessary to combine different methods. The purpose of this work is to implement a strategy for road lanes detection using the traditional Canny operator. Oriented filters are used to remove unnecessary information and vehicle’s yaw rate signal is used to adaptively correct the filter orientation according to the lane boundaries directions. In sequence, morphological filters using dilation and analysis of connected components are applied in order to remove the noise components of the edge detection stage. A linear approach for lane tracking based on Hough transform was applied and proved to be an effective technique considering a near field as region of interest, enriching the evaluation of the results. The algorithm has shown to be robust in a variety of test scenarios including reflective roads, shadows and weakened lane markings.
Andrade, David, Adamshuk, Rodrigo, Omoto, William, Franco, Felipe, Neme, João Henrique, Okida, Sergio, Tusset, Angelo, Amaral, Rodrigo, Ventura, Artur, Santos, Max Mauro Dias
The Research of the Adaptive Front Lighting System Based on GIS and GPS2017-01-00413/28/2017
Automotive Front Lighting System(AFS) can receive the steering signal and the vehicular speed signal to adjust the position of headlamps automatically. AFS will provide drivers more information of front road to protect drivers safe when driving at night. AFS works when there is a steering signal input. However, drivers often need the front road's information before they turn the steering wheel when vehicles are going to go through a sharp corner, AFS will not work in such a situation. This paper studied how to optimize the working time of AFS based on GIS (Geographic Information System) and GPS(Geographic Information System) to solve the problem. This paper analyzed the process of the vehicle is about to go through a corner. Low beams and high beams were discussed respectively. Taking into account the characteristics of GIS, GPS and driving conditions, this paper researched that when the vehicle derived on the single lane or double lane, the feasibility of the steering side headlight adjusted the position of the front light, and calculated the rotation angle and rotating angular velocity for the headlight, then determined the effective working range of the system. Then, the lighting areas of the system are showed by the simulation. The results showed that the pre-AFS can make the steering side headlight adjust the position of the lights most effectively before the vehicle go through the corner with the turning radius between 10-40 meters for low beams, and over 40 meters for high beams, it can provide more effective driving visual areas for drivers when they driving at night to reduce the incidence of accidents.
Xiong, Shengguang, Tan, Gangfeng, Guo, Xuexun, Xiao, Longjie
Road Surface Condition Detection in Bicycle for Active Safety Applications2017-01-17303/28/2017
Nowadays, the tendency of people using bicycles as the way of transportation has increased as well as the tendency of the bicycle accidents. According to the research of National Highway Traffic Safety Administration (NHTSA), National Survey on Bicyclist and Pedestrian Attitude and Behavior, the major root causes of bicycle accidents are from the road surface condition. Thus, this work has developed the system to detect the road surface condition. The system utilizes the laser and camera to measure the height of road. Then, with the information of the road height and bicycle speed, the road surface condition can be classified into 3 categories due to severe condition of the road. For the secure road, cyclists could safely ride on it. For the warning road, cyclists need to slow down the speed. Lastly, for the dangerous road, cyclists have to stop their bicycles. Also, the road surface condition information is useful for many active safety applications such as active warning systems to increase the reliability of the system and safety of cyclists.
Phanomchoeng, Gridsada, Chantranuwathana, Sunhapos
Bayesian Parameter Estimation for Heavy-Duty Vehicles2017-01-05283/28/2017
Accurate vehicle parameters are valuable for design, modeling, and reporting. Estimating vehicle parameters can be a very time-consuming process requiring tightly-controlled experimentation. This work describes a method to estimate vehicle parameters such as mass, coefficient of drag/frontal area, and rolling resistance using data logged during standard vehicle operation. The method uses a Monte Carlo method to generate parameter sets that are fed to a variant of the road load equation. The modeled road load is then compared to the measured load to evaluate the probability of the parameter set. Acceptance of a proposed parameter set is determined using the probability ratio to the current state, so that the chain history will give a distribution of parameter sets. Compared to a single value, a distribution of possible values provides information on the quality of estimates and the range of possible parameter values. The method is demonstrated by estimating dynamometer parameters. The results confirm the method’s ability to estimate reasonable parameter sets, and indicate an opportunity to increase the certainty of estimates through careful selection or generation of the test drive cycle.
Miller, Eric, Konan, Arnaud, Duran, Adam
Video Analysis of Motorcycle and Rider Dynamics During High-Side Falls2017-01-14133/28/2017
This paper investigates the dynamics of four motorcycle crashes that occurred on or near a curve (Edwards Corner) on a section of the Mulholland Highway called “The Snake.” This section of highway is located in the Santa Monica Mountains of California. All four accidents were captured on video and they each involved a high-side fall of the motorcycle and rider. This article reports a technical description and analysis of these videos in which the motion of the motorcycles and riders is quantified. To aid in the analysis, the authors mapped Edwards Corner using both a Sokkia total station and a Faro laser scanner. This mapping data enabled analysis of the videos to determine the initial speed of the motorcycles, to identify where in the curve particular rider actions occurred, to quantify the motion of the motorcycles and riders, and to characterize the roadway radius and superelevation throughout the curve. For each crash video, this paper reports quantitative data from the crash along with a qualitative description of the rider’s actions.
Rose, Nathan A., Carter, Neal, Pentecost, David, Hashemian, Alireza
The Significance to Establish a Durability Model for an Automotive Ride2017-01-03473/28/2017
This paper presents the study of a relationship between objective vertical vibration and coil spring fatigue life under different road excitation to shorten suspension design process. Current development processes of vehicle suspension systems consist of many different stages of analysis and time consuming. Through this vertical vibration and durability characterisation, the vehicle ISO weighted vertical accelerations were used to describe fatigue life of coil spring. Strain signals from various roads were measured using a data acquisition and then converted into acceleration signal. The acceleration signals were then used as input to multibody suspension model for forces time history on spring and acceleration signal of sprung mass extraction. The acceleration signals were then processed for ISO weighted indexes while the force time history was used for coil spring fatigue life prediction respectively. It has been found that the rural road contributed the lowest fatigue life and the highest weighted vertical vibration index when compared to other road conditions. The measured strain predicted fatigue life were also possessed acceptable range when compared to the simulated force fatigue life using a conservative comparison method. The vertical weighted accelerations were plotted against the measured strain and simulated force fatigue life with a coefficient correlations more than 0.99. This model provides immediate prediction between vertical weighted acceleration and fatigue of spring to shorten automotive suspension development time frame.
Kong, Yat Sheng, Schramm, Dieter, Omar, M. Zaidi, Mohd. Haris, Sallehuddin, Abdullah, Shahrum
Coupled Level-Set Volume of Fluid Simulations of Water Flowing Over a Simplified Drainage Channel With and Without Air Coflow2017-01-15523/28/2017
The motivation for this paper is to predict the flow of water over exterior surfaces of road vehicles. We present simulations of liquid flows on solid surfaces under the influence of gravity with and without the addition of aerodynamic forces on the liquid. This is done using an implementation of a Coupled Level Set Volume of Fluid method (CLSVOF) multiphase approach implemented in the open source OpenFOAM CFD code. This is a high fidelity interface-resolving method that solves for the velocity field in both phases without restrictions on the flow regime. In the current paper the suitability of the approach to Exterior Water Management (EWM) is demonstrated using the representative test cases of a continuous liquid rivulet flowing along an inclined surface with a channel located downstream perpendicular to the oncoming flow. Experimental work has been carried out to record the motion of the rivulet in this case and also to measure the contact angle of the liquid with the solid surface. The measurements of the liquid/solid characteristics such as equilibrium and dynamic contact angles are described along with the analytical expression for contact angle vs. capillary number used in the CFD code. The results from the simulations are compared to experimental measurements. The simulations are carried out with air co-flows of 0, 0.5 and 10 m/s. The simulations are seen to reproduce physical phenomena such as the liquid pinning at sharp corners and the longitudinal stretching of the rivulet with higher air velocity.
Dianat, Mehriar, Skarysz, Maciej, Hodgson, Graham, Garmory, Andrew, Passmore, Martin
Analysis of a Diesel Passenger Car Behavior On-Road and over Certification Duty Cycles2016-01-232810/17/2016
Precise, repeatable and representative testing is a key tool for developing and demonstrating automotive fuel and lubricant products. This paper reports on the first findings of a project that aims to determine the requirements for highly repeatable test methods to measure very small differences in fuel economy and powertrain performance. This will be underpinned by identifying and quantifying the variations inherent to this specific test vehicle, both on-road and on Chassis Dynamometer (CD), that create a barrier to improved testing methods. In this initial work, a comparison was made between on-road driving, the New European Drive Cycle (NEDC) and World harmonized Light-duty Test Cycle (WLTC) cycles to understand the behavior of various vehicle systems along with the discrepancies that can arise owing to the particular conditions of the standard test cycles. The engine controller of a 2.0L diesel vehicle with active de-NOx and a particulate filter (DPF) has been monitored over 13,700km of driving. The engine speed/torque operating points showed that both the NEDC and WLTC fail to capture the complete static and dynamic usage observed on the road, and are ill-equipped to capture any driver to driver variations. A cyclic analysis of the DPF is proposed, showing up to 70% variation in soot loading at the point of regeneration. This variation can be explained by the controller waiting for favorable driving conditions for regeneration. NEDC and WLTC are poor cycles for capturing DPF effects as the former presents insufficient engine powers to trigger and the later insufficient time to complete a regeneration event. Along with understanding the general contrasts between standard CD cycles and road conditions, this is a key finding for the project overall as understanding and managing DPF loading and regeneration will enable improvements to be made in test precision.
Chappell, Edward, Burke, Richard, Lu, Pin, Gee, Michael, Williams, Rod
Automotive Engineering: October 6, 201616AUTP1010/6/2016
Steering Mazda's unique course A chassis engineer at heart, Chairman Seita Kanai challenges his engineers to think differently and embrace the Skyactiv technology that has made Mazda a benchmark. Delphi's multi-domain mindset From tackling the cyber threat to putting 48-volt hybrids with Dynamic Skip-Fire on the road, Engineering VP Mary Gustanski is harnessing a technology powerhouse. The evolving tire-development paradigm Advanced tire-simulation modeling allows tire development to keep pace with accelerated vehicle-development cycles. MEMS the word for next-gen HUDs New high-speed, quad-channel laser diode drivers are designed to beat the LCD and DLP incumbents for next-gen vehicle head-up displays. Editorial: A how-to for car hackers Mazda's 2017 G-Vectoring Control brings dynamic refinement Volvo, Uber share the ride to safety with autonomy Inside Porsche's new V8 and V6 powertrains Citroën to unveil CXperience concept at 2016 Paris show With 2017 Fusion Sport, Ford pushes further toward Audi Volvo S90: Niche for now, but… 2017 Nissan Titan gets new platform, powertrain, cab and bed features James Morgan of the Lean Enterprise Institute talks Lean Product and Process Development and LPPD lessons learned from Toyota.
Lateral Control System for Autonomous Lane Change System on Highways2016-01-16414/5/2016
In this paper, we propose a vision based lateral control scheme for autonomous lane change system on highways. Three main techniques are proposed, to improve the lane keeping/lane change performance, and to reduce the ripple in the yaw rate on highways. First, we propose a model based lane prediction method to cope with the momentary failure of lane detection. Second, we innovate an approach to steering wheel angle control based on torque overlay for the EPS of the lateral control. Finally, the multi-rate lane-keeping control scheme is proposed to improve the lateral control performance and to reduce the ripple in the yaw rate. The performance of the proposed method was experimentally evaluated via test vehicle
Kang, Chang Mook, Sung Gu, Yi, Jeon, Soo Jung, Son, Young Seop, Kim, Wonhee, Lee, Seung-Hi, Chung, Chung Choo
Simulation of Atmospheric Turbulence for Wind-Tunnel Tests on Full-Scale Light-Duty Vehicles2016-01-15834/5/2016
During the past year, a novel turbulence generation system has been commissioned in the National Research Council (NRC) 9 m Wind Tunnel. This system, called the Road Turbulence System was developed to simulate with high fidelity the turbulence experienced by a heavy duty vehicle on the road at a geometrical scale of 30%. The turbulence characteristics that it can simulate were defined based on an extensive field measurement campaign on Canadian roads for various conditions (heavy and light traffic, topography, exposure) at heights above ground relevant not only for heavy duty vehicles but also for light duty vehicles. In an effort to improve continually the simulation of the road conditions for aerodynamic evaluations of ground vehicles, a study was carried out at NRC to define the applicability of the Road Turbulence System to aerodynamic testing of full-scale light duty vehicles. Using the on-road measurements as a guide, it was concluded that the RTS appears to provide a more representative simulation of on-road conditions for wind-tunnel testing, compared with other passive methods such as with rope nets, spires, large turbulence grids or also with active turbulent generation techniques. Although some differences from the target turbulence conditions were found, all spectra measured behind the RTS were found to be within the range of turbulence energy measured during the on-road campaign. As such, the RTS was subsequently used for measurements of two full-scale light-duty vehicles (a large car and a standard sport-utility vehicle) during a test campaign examining the influence of active drag-reduction technologies. Comparison of these data to the equivalent smooth-flow measurements showed different influences of turbulence on the drag behaviour for each of the two vehicles.
McAuliffe, Brian R., Wall, Alanna, Larose, Guy
Friction on Polished vs. Newly Re-Rocked Oil-and-Chip Roadway Surfaces2016-01-15684/5/2016
Roadway tractive capabilities are an important factor in accident reconstruction. In the absence of full-scale experiments, tire/road coefficient of friction values are sometimes quoted from reference textbooks. For the various types of road construction, the values are given only in the form of a wide range. One common roadway type is oil-and-chip construction. We examine stopping distances for newly-rocked oil-and-chip roads vs. similarly constructed roads that have been traffic-polished. The examination was conducted through full-scale braking experiments with instrumented vehicles. Results show that the differences between newly-rocked oil-and-chip roads when compared to roads that are traffic-polished are on the same order as vehicle, tire and ABS algorithm differences, and that full-scale testing is required for accurate μ-values.
Metz, L. Daniel
A Model-Free Stability Control Design Scheme with Active Steering Actuator Sets2016-01-16554/5/2016
This paper presents the application of a proposed fuzzy inference system as part of a stability control design scheme implemented with active steering actuator sets. The fuzzy inference system is used to detect the level of overseer/understeer at the high level and a speed-adaptive activation module determines whether an active front steering, active rear steering, or active 4 wheel steering is suited to improve vehicle handling stability. The resulting model-free system is capable of minimizing the amount of model calibration during the vehicle stability control development process as well as improving vehicle performance and stability over a wide range of vehicle and road conditions. A simulation study will be presented that evaluates the proposed scheme and compares the effectiveness of active front steer (AFS) and active rear steer (ARS) in enhancing the vehicle performance. Both time and frequency domain results are presented.
Hirche, Benjamin, Ayalew, Beshah
Modelling and Simulation of Rapidly Changing Road Gradients2016-01-16634/5/2016
In vehicle dynamics modelling, the road profile is generally treated in one of two ways; either the gradient is a property that changes over a length scale far greater than that of the vehicle's wheelbase, or as a very detailed road surface model for determining the behaviour of vehicle suspensions. Occasionally, for modelling the behaviour of off-road vehicles, step-climbing manoeuvres are modelled. We propose an extension of these step-climbing models to a general, continuously varying road gradient model for cases where the distance over which the large gradient change occurs are of similar length-scale as the vehicle wheelbase. The motivation behind this work comes from a road gradient and vehicle mass estimation problem where it was noticed that very sudden gradient changes have a significant impact on the powertrain, but in a way that is not proportional to the attitude change of the vehicle. We present an analysis applicable to these cases where the road gradient change is substantially different from the vehicle attitude change. The analysis is built up from a very basic step climbing exercise to a general case solution for two dimensional longitudinal vehicle dynamics. Methods of handling road gradient and gradient change for modelling purposes are discussed. A method is proposed that defines the gradient change as an input to a backwards dynamic model that allows us to compute torque required to achieve a pre-defined datum speed during a gradient transition. The results of simulations for simple gradient change cases are shown. We discuss the implication of these road gradient transients for vehicle parameter estimation based on powertrain behaviour.
Wragge-Morley, Robert Timothy, Herrmann, Guido, Burgess, Stuart, Barber, Phil
Aerodynamics Evaluation of Road Vehicles in Dynamic Maneuvering2016-01-16184/5/2016
A road vehicle’s cornering motion is known to be a compound motion composed mainly of forward, sideslip and yaw motions. But little is known about the aerodynamics of cornering because little study has been conducted in this field. By clarifying and understanding a vehicle’s aerodynamic characteristics during cornering, a vehicle’s maneuvering stability during high-speed driving can be aerodynamically improved. Therefore, in this study, the aerodynamic characteristics of a vehicle’s cornering motion, i.e. the compound motion of forward, sideslip and yaw motions, were investigated. We also considered proposing an aerodynamics evaluation method for vehicles in dynamic maneuvering. Firstly, we decomposed cornering motion into yaw and sideslip motions. Then, we assumed that the aerodynamic side force and yaw moment of a cornering motion could be expressed by superposing linear expressions of yaw motion parameters and those of sideslip motion parameters, respectively. Next, we conducted CFD analyses of a vehicle in dynamic meandering motions. Then, we verified the linear aerodynamic force model with the CFD analysis results. The results revealed that the aerodynamic side force and yaw moment in dynamic meandering motion could be mostly expressed with the linear aerodynamic force model. We also clarified the aerodynamic characteristics of the vehicle in dynamic meandering motion and its generation mechanism by analyzing the surface static pressure distribution on the vehicle in dynamic meandering motion by applying the concept of the linear aerodynamic force model.
Okada, Yoshihiro, Nakashima, Takuji, Tsubokura, Makoto, Morikawa, Yousuke, Kouno, Ryousuke, Okamoto, Satoshi, Matsuhiro, Tanaka, Nouzawa, Takahide
Self-Driving Intelligent Vehicle to Increase Road Safety, Lower Congestion Rates and Decrease Emissions2016-01-01614/5/2016
This study presents the design and development of a vehicle platform with intelligent sensors that has the capabilities to drive independently and cooperatively on roads. An integrated active safety system has been designed to optimize the human senses using ultrasonic infrared sensors and transmitter/receiver modules, to increase the human vision, feel and communication for increased road safety, lower congestion rates, and decrease CO2 emissions. Ultrasonic sensors mounted on the platform, emitted longitudinal 40 kHz waves and received echoes of these sound waves when an object was within its direction. The duration was converted to a distance measurement to detect obstacles as well as using distance measurement threshold values to implement adaptive cruise control. Infrared sensors equipped with an IR LED and a bipolar transistor detected a change in light intensity to identify road lanes. The wireless modules were used for vehicle-to-vehicle communication, where vehicles communicate their current speed and acceleration to each other in order to maintain a constant distance and avoid collisions and traffic congestion. The intelligent vehicle is capable of implementing adaptive cruise control, obstacle avoidance, lane keeping/changing, emergency braking, and vehicle-to-vehicle communication. Under development in this research is to add a vision system and image processing techniques to detect road lanes, obstacles, and traffic lights or signs and also a fusion between a GPS module, rotary encoder and inertial sensor able to self-drive and see incoming traffic not in sight yet in a city environment.
Soloiu, Valentin, Augusma, Imani, Lucien, Deon, Thomas, Mary, Alba-Flores, Roccio
Process Automation to Generate Road Drive Files in Laboratory Testing Using Virtual Iterations Method2016-01-13594/5/2016
At present, vehicle testing in laboratory is one of the important phase to quicken the product validation process. In the early phase of laboratory testing it is required to evaluate the strength of the vehicle structure through physical rig setup which represents the consumer’s usage. Two and Multiple poster input excitation are among the laboratory rig testing to represent the actual road are used to predict the durability of vehicle components. The road inputs through the poster are known as drive files, a feedback controlled system which reproduces the track or real road recorded specimen’s accelerations, displacements and strains in laboratory. Derivation of drive files in poster testing requires iteration of physical specimen to exactly replicate the actual road. This paper discusses about generation of drive files as inputs for poster actuation with virtual model(as a substitute for actual model)which is applicable in areas of vehicle durability and ride comfort studies. For the reason to minimize the time,cost,man-machine hours and energy, an automation is developed to simulate the validated virtual model with iterations process to generate the road files for further use in physical and virtual test.The paper details on the procedure followed traditionally and what changes have been made in the current process to generate road drive input files.
Pradeepak, R., Kumbhar, Shyamsundar, Barhate, Nainishkumar
Optimization of Suspension System of Self-Dumping Truck Using TOPSIS-based Taguchi Method Coupled with Entropy Measurement2016-01-13854/5/2016
This study presents a hybrid optimization approach of TOPSIS-based Taguchi method and entropy measurement for the determination of the optimal suspension parameters to achieve an enhanced compromise among ride comfort, road friendliness which means the extent of damage exerted on the road by the vehicles, and handling stabilities of a self-dumping truck. Firstly, the full multi-body dynamic vehicle model is developed using software ADAMS/Car and the vehicle model is then validated through ride comfort road tests. The performance criterion for ride comfort evaluation is identified as root mean square (RMS) value of frequency weighted acceleration of cab floor, while the road damage coefficient is used for the evaluation of the road-friendliness of a whole vehicle. The lateral acceleration and roll angle of cab were defined as evaluation indices for handling stability performance. The spring stiffness and shock absorber damping of the front suspension, spring stiffness of the rear suspension, torsional stiffness of the front and rear anti-roll bar are taken as the design variables, which are considered at three levels. A L18 orthogonal array is applied to implement the simulations, and the TOPSIS is thus used to integrate all determined performance criteria of ride comfort, road friendliness and handling stability into a single performance index. Meanwhile, the weights of the quality characteristics are determined by employing the entropy measurement method. Furthermore, the best factor levels are identified according to the Taguchi method principles for single response optimization. Finally, the optimal combination of suspension parameters is confirmed to illustrate the effectiveness of the proposed hybrid optimization method.
Jiang, Rongchao, Wang, Dengfeng
Real Time Drivable Surface Determination Based on Stereo Vision2016-01-01694/5/2016
For any autonomous vehicle, understanding which area around the vehicle is free or drivable is a key component. It is important to find road boundaries such as ditches, curbs or guard rails. Finding small objects on the road, that might be blocking the vehicle path, is also critical. Most prototypes for autonomous vehicles feature laser scanners for this purpose. We propose a stereo vision based system as redundancy or as a cost efficient replacement for laser scanners in the application of drivable surface determination. The system generates a detailed map that indicates which area in front of the vehicle that is considered to be drivable and non-drivable. The base for this map is a dense 3D point cloud generated from the stereo vision system. The left and right images are used to create a disparity image which is then translated into a 3D point cloud. The 3D points are used to generate a detailed elevation grid of the observed area. The gradient of this grid is then used for the judgement of drivable/non-drivable. The 3D point cloud and the drivability map is generated in real time at 22 Hz on production intent hardware. We demonstrate the performance on a variety of use cases. We show that stereo vision is a strong candidate to replace the laser scanners used in many autonomous driving applications. At the same time our stereo vision system features many other applications, such as EuroNCAP AEB, lane tracking and traffic sign recognition.
Eidehall, Andreas, Askling, Joel, Spies, Hagen
Items per page:
1 – 50 of 411