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Technical Paper
2014-04-01
Gary A. Davis
Abstract The critical speed method uses measurements of the radii of yawmarks left by vehicles, together with values for centripetal acceleration, to estimate the speeds of the vehicles when the yawmarks were made. Several field studies have indicated that equating the centripetal force with braking friction produced biased estimates, but that the biases tended to be small (e.g. within 10%-15% on average) and led to underestimates, suggesting that the method can be useful for forensic purposes. Other studies, however, have challenged this conclusion. The critical speed method has also seen use in safety-related research, where it is important to have a reliable assessment of the uncertainty associated with a speed estimate. This paper describes a variant of the critical speed method, where data from field tests lead to an informative prior probability distribution for the centripetal acceleration. Using Bayes theorem, this distribution is combined with the measured radius to produce a posterior probability distribution for the desired speed.
Technical Paper
2014-04-01
Renaud Deborne, Skárlet Khouri Silva, Andras Kemeny
Abstract By the action on the steering wheel, the driver has the capability to control the trajectory of its vehicle. Nevertheless, the steering wheel has also the role of information provider to the driver. In particular, the torque level at the steering wheel informs the driver about the interaction between the vehicle and the road. This information flow is natural due to the mechanical chain between the road and the steering wheel. Many studies have shown that steering wheel torque feedback is crucial to ensure the control of the vehicle. In the context of uncoupled steering (steer-by-wire vehicle or driving simulators), the torque rendering on the steering wheel is a major challenge. In addition, of the trajectory control, the quality of this torque is a key for the immersion of drivers in virtual environment such as in driving simulators. The torque-rendering loop is composed of different steps. At first, a vehicle dynamics model computes the torque level at the steering wheel regarding the vehicle state (steering wheel position, vehicle speed, etc.).
Technical Paper
2014-04-01
Flaura Winston, Catherine McDonald, Venk Kandadai, Zachary Winston, Thomas Seacrist
Abstract Driving simulators offer a safe alternative to on-road driving for the evaluation of performance. In addition, simulated drives allow for controlled manipulations of traffic situations producing a more consistent and objective assessment experience and outcome measure of crash risk. Yet, few simulator protocols have been validated for their ability to assess driving performance under conditions that result in actual collisions. This paper presents results from a new Simulated Driving Assessment (SDA), a 35- to-40-minute simulated assessment delivered on a Real-Time® simulator. The SDA was developed to represent typical scenarios in which teens crash, based on analyses from the National Motor Vehicle Crash Causation Survey (NMVCCS). A new metric, failure to brake, was calculated for the 7 potential rear-end scenarios included in the SDA and examined according two constructs: experience and skill. The study included an inexperienced group (n=21): 16-17 year olds with 90 days or fewer of provisional licensure, and an experienced group (n=17): 25-50 year olds with at least 5 years of PA licensure, at least 100 miles driven per week and no self-reported collisions in the previous 3 years.
Technical Paper
2014-04-01
Masayuki Naito, Yasuhiro Koike, Shintaro Osaki, Shinichiro Morishita, Nanhao Quan
Abstract HEV and EV markets are in a rapid expansion tendency. Development of low-cost regenerative cooperation brake system is needed in order to respond to the consumers needs for HEV and EV. Regenerative cooperation brake system which HEV and EV are generally equipped with has stroke simulator. We developed simple composition brake system based on the conventional ESC unit without the stroke simulator, and our system realized a low-cost regenerative cooperation brake. The key technologies are the quiet pressurization control which can be used in the service application, which is to make brake force depending on brake travel, by gear pump and the master cylinder with idle stroke to realize regenerative cooperation brake. Thanks to the key technologies, both the high regenerative efficiency and the good service brake feeling were achieved.
Technical Paper
2014-04-01
Michael Flad, Simon Rothfuss, Gunter Diehm, Sören Hohmann
Brake pedal feedback is important for driver's perception during the driving task as well as the pedal feel is an important factor in customer satisfaction. Therefore, a force emulation device is beneficial during the design phase to evaluate the pedal characteristic. Such a system is also needed for driving simulators. Usually, brake feedback systems in simulators rely on passive elements like springs and dampers to emulate the force. This does not allow the implementation of an arbitrary nonlinear pedal force characteristic. In this paper we propose an active pedal feedback simulator which can emulate an arbitrarily customizable and online adjustable brake pedal characteristic. The particular advantage of our pedal simulator is that the system can also emulate the exact pedal dynamics. This is advantageous compared to other active brake feedback simulators which rely on hydraulic actors. We show the mechatronic, electronic and software concept along with the required control framework and state observer.
Technical Paper
2014-04-01
Zeyu Ma, Jinglai Wu, Yunqing Zhang, Ming Jiang
The main purpose of this research is to investigate the optimal design of pipeline diameter in an air brake system in order to reduce the response time for driving safety using DOE (Design of Experiment) method. To achieve this purpose, this paper presents the development and validation of a computer-aided analytical dynamic model of a pneumatic brake system in commercial vehicles. The brake system includes the subsystems for brake pedal, treadle valve, quick release valve, load sensing proportional valve and brake chamber, and the simulation models for individual components of the brake system are established within the multi-domain physical modeling software- AMESim based on the logic structure. An experimental test bench was set up by connecting each component with the nylon pipelines based on the actual layout of the 4×2 commercial vehicle air brake system. The experimental data of the transient pressure in both secondary and primary brake circuits was measured to verify the simulation accuracy and the positive results of the validation show a potential for investigating the most suitable parameter configuration of the pipeline diameter based on the computer-aided analytical dynamic models.
Technical Paper
2014-04-01
Boyuan Li, Haiping Du, Weihua Li
The omni-directional vehicle is an innovative vehicle, in which the in-wheel steering motor and in-wheel driving motor are integrated into each wheel of the vehicle so that each wheel can be independently controlled to have traction, braking, and turning motions to improve the vehicle's mobility, handling and stability. To realize good performance, various control strategies have been proposed, like the active steering control and the direct yaw moment control, where the accurate slip angle information is critical to these control strategies. However, in practice, the side slip angle is hard or expensive to be measured for a passenger vehicle, therefore, different estimation methods have been proposed in the literature. In this paper, a novel side slip angle estimation method is proposed for the omni-directional vehicle that has four independent steering motors. This method includes the estimation of total alignment torque and side slip angle, and only needs the measurements of steering angles and steering motor currents, which are available by using angle sensors and current sensors embedded with the in-wheel steering motors.
Technical Paper
2014-04-01
Chi Jin, Lu Xiong, Zhuoping Yu, Yuan Feng
Abstract In this paper we present a path following control design for a six-wheel skid-steering vehicle. Contrary to the common approaches that impose non-holonomic constraints, a dynamic vehicle model is established based on a pseudo-static tire model, which uses tire slip to determine tire forces. Our control system admits a modular structure, where a motion controller computes the reference vehicle yaw rate and reference vehicle speed and a dynamics controller tracks these signals. A robust nonlinear control law is designed to track the reference wheel speeds determined by the dynamics controller with proved stability properties. Saturated control techniques are employed in designing the reference yaw rate, which ensures the magnitude of the reference yaw rate does not violate the constraint from the ground-tire adhesion. The simulation results demonstrate the effectiveness of the proposed path following control design.
Technical Paper
2014-04-01
Zhiting Zhu, Lu Xiong, Chi Jin
Abstract The control in transient conditions when hydraulic brake and regenerative brake switch mutually is the key technical issue about electric vehicle hybrid brake system, which has a direct influence on the braking feel of driver and vehicle braking comfort. A coordination control system has been proposed, including brake force distribution correction module and motor force compensation module. Brake force distribution correction module has fixed the distribution results in hydraulic brake force intervention condition, hydraulic brake force evacuation condition and regenerative brake force low speed evacuation condition. Motor compensation module has compensated hydraulic system with motor system, which has fast and accurate response, thus the response of whole hybrid system has been improved. Simulation results in transient conditions show that the coordination control strategy can effectively reduce the fluctuations and deviations of total brake force, and improve braking feel of driver and vehicle braking comfort.
Technical Paper
2014-04-01
Hu Zhang, JianWei Zhang, Konghui Guo
Abstract Whether high-precision torque control or motor condition monitoring need accurate motor parameters. For the three parameters of surface-mounted permanent magnet synchronous motor (SPMSM), the voltage equation is rank-deficient. To solve this problem, some scholars proposed methods that build full rank equations with signal injection, but this will produce motor torque ripple, which is not suitable for application to the EPS. Therefore, this paper proposes a method based on MRAS to identify motor parameters step by step. The proposed two steps identification method can make the reference model full rank in every step, but the total decoupling between parameters identification processes cannot be realized for the assumption that the prior step result is the real value. It was found in experiment that this effect varies with the motor operating conditions. Therefore, this paper analyzes the sensitivity of the motor parameters and proposes a method to improve the accuracy of identification results by changing the weight of identification results according to the operating conditions.
Technical Paper
2014-04-01
Suhas Kangde, Vishal Shitole, Ashish Kumar Sahu
Abstract Automotive Suspension is one of the critical system in load transfer from road to Chassis or BIW. Using flex bodies in Multi body simulations helps to extract dynamic strain variation. This paper highlights how the MBD and FE integration helped for accurate strain prediction on suspension components. Overall method was validated through testing. Good strain correlation was observed in dynamic strains of constant amplitude in different loading conditions. Combination of different direction loading was also tested and correlated. Method developed can be used in the initial phase of the vehicle development program for suspension strength evaluation. Suspension is one of the important system in vehicle which is subjected to very high loading in all the directions. To predict the dynamic stresses coming on the suspension system due to transient loads, faster and accurate method is required. To accelerate the suspension design process it become necessary to get good accuracy in the results.
WIP Standard
2014-04-01
This SAE Standard applies to the usage of tires of the same nominal size and tread type, but with different outside diameter for articulated front-end loaders. Articulated four-wheel-drive front-end loader performance and component life can be affected by excessive differences in the tire outside circumference and/or diameter. The purpose is to provide specific guidelines for the usage of tires with different outside circumference and/or diameter on articulated front-end loaders.
Collection
2014-04-01
This technical paper collection focuses on new theory, formulation and modeling of amplitude-, frequency- and temperature-dependent nonlinear components/systems such as rubber and hydraulic mounts or bushings, shock absorbers, and any joint friction/damping; dynamic characterization through lab and field testing; Linearization methodology; Model validation, application, and sensitivity analysis in vehicle system/subsystem simulations; Nonlinear system identification, modeling, and application in testing accuracy improvement, etc.
Collection
2014-04-01
This technical paper collection is focused on vehicle dynamics and controls using modeling and simulation, and experimental analysis of passenger cars, heavy trucks, and wheeled military vehicles. The papers address active and passive safety systems to mitigate rollover, yaw instability and braking issues; driving simulators and hardware-in-the-loop systems; suspension kinematics and compliance, steering dynamics, advanced active suspension technologies; and tire force and moment mechanics.
Collection
2014-04-01
This technical paper collection presents papers on steering and suspension related topics as it applies to ground vehicles. Papers for this session address new approaches as well as advances in application of steering, suspension related technologies.
Article
2014-03-24
A sophomore nabbed the top spot in a steel wheels competition focused on eye-appealing, lightweight-structure concept renderings from Lawrence Technological University design students. The 2014 competition required student designers to use the engineering results from the Steel Market Development Institute’s Lightweight Steel Wheel Project.
Technical Paper
2014-03-24
Jeonghoon Song
In this study, a model of Active Front wheel Steer (AFS) system are developed and tested. In addition, an Integrated Dynamics Control with Front steer (IDCF) controller is also designed to investigate the performance of AFS system when it is integrated with a brake system. The IDCF system composed of an AFS system and a DYC (Direct Yaw moment Control) system of rear wheels. The AFS controller and IDCF controller are compared under several driving and road conditions with and without braking input and steering input. A 8 degree of freedom vehicle model is also employed to test the controllers. The results show that the model of AFS system shows good kinematic steering assistance function. Steering ratio varies depends on vehicle velocity between 12 and 24. Kinematic stabilization function also shows good performance because yaw rate of AFS vehicle tracks the reference yaw rate. IDCF shows improved responses compared to AFS because body side slip angle is also reduced regardless of road condition, steer input and brake input.
Technical Paper
2014-03-24
Teerapharp Amornsawaddirak, Sittikorn Lapapong, Szathys Songschon, Masaaki Okuma
In an automotive suspension, a shock absorber plays a significant role to enhance the vehicle performances, particularly ride comfort and road holding. Because of its important influences on the overall vehicle performances, the understanding of its physical characteristics is essential. Thus, this paper develops a mathematical model of twin-tube shock absorber that is widely used in modern production cars. The model is derived based on a rational polynomial formulation. This formulation generally represents the flow behaviors of fluid across a restriction. Further, simulation results are compared to those obtained from experiments to determine the model accuracy. The result comparison illustrates that the model is able to describe the behavior of shock absorber with slight discrepancies.
Article
2014-03-19
Bridgestone's M854 wide-base radial all-position tire is fabricated for severe on/off highway applications.
Article
2014-03-19
Dana Holding updates technology to support the Spicer central tire inflation system with a mechatronic control unit option.
Article
2014-03-19
Goodyear G731 MSA and G751 MSA tires for mixed-service applications enable construction, dump, cement mixers, and other fleets to travel across challenging surfaces.
Article
2014-03-19
Meritor’s P600 Series planetary axles, including the P610 and P614, are engineered for global heavy-haul, oil field, logging, and mining applications.
Article
2014-03-18
The TII Group manufactures heavy transport vehicles for the heavy load and road transport sector including the Scheuerle InterCombi highway trailer.
Article
2014-03-18
Webb Vortex brake drums from Webb Severe Duty are suitable for high frequency stopping applications such as refuse trucks and other fleets that carry heavy loads and make repeated stops throughout their daily operation.
Article
2014-03-18
The RL45 and RL51 off-road radial tires from Yokohama Tire feature durable and long-lasting treads for demanding applications.
WIP Standard
2014-03-07
The purpose of this SAE Recommended Practice is set guidelines for tire to wheel house and body clearances on recreational vehicles.
WIP Standard
2014-03-07
This SAE Recommended Practice covers the tubing intended primarily for use as hydraulic brake lines on motor vehicles. It covers materials, manufacturing processes, and general properties required to meet the wide range of service encountered in automotive applications. To meet this need, it must be formed, assembled, handled, and installed in accordance with sound engineering and manufacturing practices. This specification covers only the basic tubing and does not include attachments such as protective armor or end fittings. This document is not intended to be used for quality control purposes. Design guidelines are shown in Appendix A.
WIP Standard
2014-03-05
This SAE Recommended Practice provides a test method and instructions for measuring performance of parking brakes on air- or hydraulic-braked vehicles equipped with in-wheel or drive-line parking brakes. This procedure applies to truck, tractor, trailer, and bus.
Article
2014-03-04
TRW Automotive's steering-wheel concept being shown at the 2014 Geneva Motor Show supports semi and fully automated driving via several multifunctional features including hands on/off detection. The steering wheel is featured in Rinspeed's steer-by-wire XchangE electric vehicle concept.
WIP Standard
2014-03-04
This SAE Standard is used to determine the mass per unit area, in grams per square meter, of materials used for trimming automobile interiors.
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