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Viewing 241 to 270 of 9920
Technical Paper
2014-04-01
Scott Varnhagen, Donald Margolis
The use of electric motors to independently control the torque of two or four wheels of a vehicle has the potential to significantly improve safety and handling. One virtue of electric motors is that their output torque can be accurately estimated. Using this known output torque, longitudinal tire force and coefficient of friction can be estimated via a controller output observer. This observer works by constructing a model of wheel dynamics, with longitudinal tire force as an unknown input quantity. A known wheel torque is input to the physical and modeled system and the resulting measured and predicted wheel speeds are compared. The error between the measured and predicted wheel speed is driven towards zero by a robust feedback controller. This controller modulates an estimate of longitudinal tire force used as an input by the wheel dynamics model. The resulting estimate of longitudinal tire force quickly converges towards the actual value with minimal computational expense. Using this estimate, a methodology for controlling tire slip ratio is presented.
Technical Paper
2014-04-01
Jianmin Dang, Hui Chen, Bolin Gao, Qi Li, Minhao Li, Takeshi Watanabe, Ryouhei Hayama, Liming Lou, Shirou Nakano
To overcome the shortcomings of subjective evaluation, there have been several studies to examine the correlations between subjective and objective evaluations of on-center steering feel, and some useful results are obtained. However, it is still not clear how to design the steering characteristic based on the correlations. In this paper, we propose a methodology of identifying the optimal on-center steering force characteristic based on the correlations between subjective and objective evaluations. Firstly, significant correlations between subjective and objective evaluations regarding on-center steering feel are established and verified. These verified correlations are then used to design the steering force characteristic. With desired ratings of the subjective evaluation items set as optimization goals, the ideal values of objective evaluation indices are obtained by use of an optimal design method. At last, the optimal steering force characteristic is designed based on the ideal objective indices.
Technical Paper
2014-04-01
Mario Hrgetic, Josko Deur, Vladimir Ivanovic, Eric Tseng
Abstract This paper presents the extended Kalman filter-based sideslip angle estimator design using a nonlinear 5DoF single-track vehicle dynamics model with stochastic modeling of tire forces. Lumped front and rear tire forces have been modeled as first-order random walk state variables. The proposed estimator is primarily designed for vehicle sideslip angle estimation; however it can also be used for estimation of tire forces and cornering stiffness. This estimator design does not rely on linearization of the tire force characteristics, it is robust against the variations of the tire parameters, and does not require the information on coefficient of friction. The estimator performance has been first analyzed by means of computer simulations using the 10DoF two-track vehicle dynamics model and underlying magic formula tire model, and then experimentally validated by using data sets recorded on a test vehicle.
Technical Paper
2014-04-01
Tao Sun, Yuping He, Jing Ren
To date, various control strategies based on linear vehicle models have been researched and developed for improving lateral stability of car-trailer (CT) systems. Is a linear-model-based controller applicable to active safety systems for CT systems under emergency operating conditions, such as an evasive maneuver at high lateral accelerations? In order to answer the question, the applicability of an active trailer differential braking (ATDB) controller designed using a linear CT model is tested and evaluated, while the controller being applied to a CT system represented by a linear and a nonlinear CT model. The current research leads to the following insightful findings: the ATDB controller designed using the linear model can effectively improve the lateral stability of CT systems under regular evasive maneuvers at low lateral accelerations, but the controller is not applicable to CT active safety systems under emergency evasive maneuvers at high lateral accelerations. The insightful findings resulted from the paper will provide valuable design guidelines for the development of active safety systems for CT systems.
Technical Paper
2014-04-01
Toshiya Hirose, Masato Gokan, Nobuyo Kasuga, Toichi Sawada
Collision avoidance systems for rear-end collisions have been researched and developed. It is necessary to activate collision warnings and automatic braking systems with appropriate timing determined by a monitoring system of a driver's braking action. Although there are various systems to monitor driving behavior, this study aims to create a monitoring system using a driver model. This study was intended to construct a model of a driver's braking action with the Time Delay Neural Network (TDNN). An experimental scenario focuses on rear-end collisions on a highway, such as the driver of a host vehicle controlling the brake to avoid a collision into a leading vehicle in a stationary condition caused by a traffic jam. In order to examine the accuracy of the TDNN model, this study used four parameters: the number of learning, the number of neurons in the hidden layer, the sampling time with 0.01 second as a minimum value, and the number of the delay time. In addition, this study made a comparative review of the TDNN model and the Neural Network (NN) model to examine the accuracy of the TDNN model.
Technical Paper
2014-04-01
Jeremy Kolansky, Amandeep Singh, Jill Goryca
Ride control of military vehicles is challenging due to varied terrain and mission requirements such as operating weight. Achieving top speeds on rough terrain is typically considered a key performance parameter, which is always constrained by ride discomfort. Many military vehicles using passive suspensions suffer with compromised performance due to single tuning solution. To further stretch the performance domain to achieving higher speeds on rough roads, semi-active suspensions may offer a wide range of damping possibilities under varying conditions. In this paper, various semi-active control strategies are examined, and improvements have been made, particularly, to the acceleration-driven damper (ADD) strategy to make the approach more robust for varying operating conditions. A seven degrees of freedom ride model and a quarter-car model were developed that were excited by a random road process input modeled using an auto-regressive time series model. The proposed strategy shows promise as a cost-effective solution to improve the ride of a military vehicle over multiple stochastic terrains considering variation in operating weight.
Technical Paper
2014-04-01
Ibrahim A. Badiru
The automotive industry is one of the most competitive enterprises in the world. Customers face an ever-expanding number of entries in each market segment vying for their business. Sales price, brand image, marketing, etc. all play a role in purchase decisions, but the factor distinguishing products that consistently perform in the market place is the ability to satisfy the customer. Steering character plays a critical role in the customer driving experience and can be one of the most heavily debated topics during a new vehicle program. The proliferation of EPS steering systems now allows engineers to calibrate steering feel to almost any desired specification. This raises a key question: What subjective & objective characteristics satisfy customers in a particular market segment? Answering this question requires continued research to develop objective metrics correlated to subjective steering attributes and increased understanding of customer preferences for objective performance parameters.
Technical Paper
2014-04-01
Masashi Terada, Takashi Kondo, Yukihiro Kunitake, Kunitomo Miyahara
Abstract In automobile development, steering vibrations caused by engine excitation force and suspension vibration input from the road surface are a problem. The conventional method of reducing vibrations and thereby securing marketability has been to dispose a dynamic damper inside the steering wheel. The resonance frequency of a steering system varies for each vehicle developed (as a result of the vehicle size, the arrangement of the stiff members of the vehicle body, and the like). As a result, the individual values of dynamic dampers that are used with vehicles must be adjusted for each developed vehicle type. To address this problem, we have developed a new structure in which, rather than using a conventional dynamic damper, we disposed a floating bush on the Supplemental Restraint System (SRS) module attachment section and used the SRS module itself as the weight for the dynamic damper. In this structure, the dynamic damper weight is approximately eight times greater than the conventional weight, the vibration reduction effect is enhanced, and the effective frequency range is widened.
Technical Paper
2014-04-01
Ryan M. Ashby, JongYun Jeong, Shreesha Y. Rao, Gary J. Heydinger, Dennis A. Guenther
This research was to model a 6×4 tractor-trailer rig using TruckSim and simulate severe braking maneuvers with hardware in the loop and software in the loop simulations. For the hardware in the loop simulation (HIL), the tractor model was integrated with a 4s4m anti-lock braking system (ABS) and straight line braking tests were conducted. In developing the model, over 100 vehicle parameters were acquired from a real production tractor and entered into TruckSim. For the HIL simulation, the hardware consisted of a 4s4m ABS braking system with six brake chambers, four modulators, a treadle and an electronic control unit (ECU). A dSPACE simulator was used as the “interface” between the TruckSim computer model and the hardware.
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
Zeyu Ma, Jinglai Wu, Yunqing Zhang, Ming Jiang
In this paper, a new computational method is provided to identify the uncertain parameters of Load Sensing Proportional Valve (LSPV) in a heavy truck brake system by using the polynomial chaos theory. The simulation model of LSPV is built in the software AMESim depending on structure of the valve, and the estimation process is implemented relying on the experimental measurements by pneumatic bench test. With the polynomial chaos expansion carried out by collocation method, the output observation function of the nonlinear pneumatic model can be transformed into a linear and time-invariant form, and the general recursive functions based on Newton method can therefore be reformulated to fit for the computer programming and calculation. To improve the estimation accuracy, the Newton method is modified with reference to Simulated Annealing algorithm by introducing the Metropolis Principle to control the fluctuation during the estimation process and escape from the local minima. The comparison between the introduced computational method and other estimation method indicates that the proposed method can be performed with higher convergence speed and robustness.
Technical Paper
2014-04-01
Massimiliano Gobbi, Giampiero Mastinu, Giorgio Previati, Mario Pennati
The measurement of the contact forces between road and tires is of fundamental importance while designing road vehicles. In this paper, the design and the employment of measuring wheels for trucks and heavy vehicles is presented. The measuring wheels have been optimized in order to obtain high stiffness and the approximately the same mass of the wheels normally employed. The proposed multicomponent measuring wheels are high- accuracy instruments for measuring the dynamic loads during handling and durability testing. The measuring wheels can replace the wheels of the truck under normal operation. Such family of wheels plays a major role in modern road vehicles development. The measuring wheel concept design is based on a patented three-spoke structure connected to the wheel rim. The spokes are instrumented by means of strain gauges and the measuring wheel is able to measure the three forces and the three moments acting at the interface between the tire and the road. It uses an inboard digital system for wireless data transmission.
Technical Paper
2014-04-01
Ankang Jin, Weiguo Zhang, Shihu Wang, Yu Yang, Yunqing Zhang
The suspension system of a heavy truck's driver seat plays an important role to reduce the vibrations transmitted to the seat occupant from the cab floor. Air-spring is widely used in the seat suspension system, for the reason that its spring rate is variable and it can make the seat suspension system keep constant ‘tuned’ frequency compared to the conventional coil spring. In this paper, vibration differential equation of air-spring system with auxiliary volume is derived, according to the theory of thermodynamic, hydrodynamics. The deformation-load static characteristic curves of air-spring is obtained, by using a numerical solution method. Then, the ADAMS model of the heavy truck's driver seat suspension system is built up, based on the structure of the seat and parameters of the air-spring and the shock-absorber. At last, the model is validated by comparing the simulation results and the test results, considering the seat acceleration PSD and RMS value.
Technical Paper
2014-04-01
Guangzhong Xu, Nong Zhang
This paper presents the modeling and characteristic analysis of roll-plane and pitch-plane combined Hydraulically Interconnected Suspension (HIS) system. Vehicle dynamic analysis is carried out with four different configurations for comparison. They are: 1) vehicle with spring-damper only, 2) vehicle with roll-plane HIS, 3) vehicle with pitch-plane HIS and 4) vehicle with roll and pitch combined HIS. The modal analysis shows the unique modes-decoupling property of HIS system. The roll-plane HIS increases roll stiffness only without affecting other modes, and similarly pitch-plane HIS increases the pitch stiffness only with minimum influence on other modes. When roll and pitch plane HIS are integrated, the vehicle ride comfort and handling stability can be improved simultaneously without compromise. A detailed analysis and discussion of the results are provided to conclude the paper.
Technical Paper
2014-04-01
David H. Myszka, Jonathan Lauden, Patrick Joyce, Andrew Murray, Christoph Gillum
Automotive starting systems require substantial amounts of mechanical energy in a short period of time. Lead-acid batteries have historically provided that energy through a starter motor. Springs have been identified as an alternative energy storage medium and are well suited to engine-starting applications due to their ability to rapidly deliver substantial mechanical power and their long service life. This paper presents the development of a conceptual, spring-based starter. The focus of the study was to determine whether a spring of acceptable size could provide the required torque and rotational speed to start an automotive engine. Engine testing was performed on a representative 600 cc, inline 4-cylinder internal combustion engine to determine the required torque and engine speed during the starting cycle. An optimization was performed to identify an appropriate spring design, minimizing its size. Results predict that the test engine could be started by a torsional steel spring with a diameter and length of approximately 150 mm, similar in size, but lower weight than an electrical starting system of the engine.
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
2014-03-14
This SAE Standard covers motor vehicle brake fluids of the nonpetroleum type, based upon glycols, glycolethers and appropriate inhibitors, for use in the braking system of any motor vehicle such as a passenger car, truck, bus, or trailer. These fluids are not intended for use under arctic conditions. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM).
WIP Standard
2014-03-14
This SAE Standard covers motor vehicle brake fluids of the nonpetroleum type, based upon glycols, glycol ethers, and borates of glycolethers, and appropriate inhibitors, for use in the braking system of any motor vehicle such as a passenger car, truck, bus, or trailer. These fluids are not intended for use under arctic conditions. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM).
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
2014-03-07
The purpose of this SAE Recommended Practice is set guidelines for tire to wheel house and body clearances on recreational vehicles.
WIP Standard
2014-03-05
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.
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