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Viewing 61 to 90 of 10218
2015-04-14
Journal Article
2015-01-1580
He Dengbo, Lu Hui, Yu Fan
Abstract The vehicle chassis integrated control system can improve the stability of vehicles under extreme conditions using tire force allocation algorithm, in which, the nonlinearity and uncertainty of tire-road contact condition need to be taken into consideration. Thus, An MPC (Model Predictive Control) controller is designed to obtain the additional steering angle and the additional yaw moment. By using a robust optimal allocation algorithm, the additional yaw moment is allocated to the slip ratios of four wheels. An SMC (Sliding-Mode Control) controller is designed to maintain the desired slip ratio of each wheel. Finally, the control performance is verified in MATLAB-CarSim co-simulation environment with open-loop manoeuvers.
2015-04-14
Technical Paper
2015-01-1508
Lijiao Yu, Hongyu Zheng
Abstract As electric technique develops fast, steering system changes from conventional mechanic steering system to Hydraulic Power Steering (HPS). Flowing HPS, Electrically Controlled Steering (ECS) system, including Electric Power Steering (EPS) system, Active Front Steering (AFS) system and Steer-by-Wire (SBW) system. ECS makes it easy for a driver to control a steering wheel using a less torque at a low speed, which is usually called steering portability Besides, ECS could also help a driver steer a vehicle stably at a high speed, which is usually called steering stability ECS provides an optional method to solve the contradiction between steering portability and steering stability. [1] [2] The study of ECS involves mechanic design, detection of electric components, software design and so on. Researches of ECS need a lot of trials and errors. By now, the development of ECS mostly depends on experiments on Hardware-in-the- Loop (HIL) and real vehicles.
2015-04-14
Journal Article
2015-01-1507
Kentaro Komori, Takahito Nagataki
Abstract Research to respond to demands for improving usability of passenger vehicles has played important roles. Some aspects can be attributed to friction behavior of the steering and suspension components. In this study, we focus on an approach to improve handling, steering feel and ride-comfort of a vehicle by applying the appropriate friction behavior to tie-rod end ball joint. To control not only friction coefficient but also static-kinetic transient behavior, we investigate the potential use of diamond-like carbon (DLC) coatings. Different DLC coatings varied widely in hydrogen content, mechanical properties and micro-surface roughness are applied to the ball studs. Friction behavior corresponds to material characteristics and surface roughness of DLC.
2015-04-14
Journal Article
2015-01-1511
Srikanth Sivaramakrishnan, Kanwar Bharat Singh, Peter Lee
Abstract Anti-lock Braking System (ABS) is a critical safety component and its performance is crucial for every vehicle manufacturer. The tire plays an important role during an ABS braking maneuver as it is the component that connects the vehicle to the ground and is responsible for generating braking force. The steady-state and transient properties of the tire affect the operation of the vehicle's ABS system and consequently affects its performance/ operational efficiency. The main objective of this study is to investigate how tire design changes influence its interaction with the ABS and its eventual effect on stopping distance. This was conducted through an experimental study where tires were built with three levels of variation in carcass stiffness, tread stiffness and tread compound. Following this, ABS braking maneuvers were performed on two instrumented vehicles including a mid-tier sedan and a high-performance sports car.
2015-04-14
Technical Paper
2015-01-1504
WeiNing Bao
Abstract A ball screw regenerative shock absorber was designed for the relief of the vehicle vibration and the energy recovery of the vehicle vibration. The effect of its main parameters on the suspension system was numerically analyzed. According to the principle of the ball screw regenerative suspension system, a mathematical model of the ball screw regenerative shock absorber was established regarding the ball screw rotational inertia, the motor rotational inertia, the screw lead and the radius of the screw nut. A suspension dynamic model based on the ball screw regenerative shock absorber was developed combining the road model and the two-degrees-of-freedom suspension dynamic model.
2015-04-14
Technical Paper
2015-01-1502
Liangyao Yu, Wenwei Xuan, Liangxu Ma, Jian Song, Xianmin Zhu, Shuai Cheng
Abstract The earth's fossil energy is not limitless, and we should be taking advantage of the highly developed fields of science and technology to utilize it more efficiently and to create a fully environmentally friendly life. Considering the prodigious amount of vehicles in the world today, even a small improvement in their energy-saving performance could have a significant impact. In this paper, a new type of electro-hydraulic power steering (EHPS) system is described. It has two main advantages. First, it can significantly decrease the demand on the motor so that it can be used for a wider range of vehicles. Second, its pressure-flow characteristic can be programmed and is more flexible than hydraulic power steering (HPS) system. A prototype with a 500 W motor was applied to a truck with a front load of 2,700 kg, and static steer sweep tests were conducted to validate its feasibility.
2015-04-14
Journal Article
2015-01-1506
Bastian Scheurich, Tilo Koch, Michael Frey, Frank Gauterin
Abstract Today, body vibration energy of passenger cars gets dissipated by linear working shock absorbers. A new approach substitutes the damper of a passenger car by a cardanic gimbaled flywheel mass. The constructive design leads to a rotary damper in which the vertical movement of the wheel carrier leads to revolution of the rotational axis of the flywheel. In this arrangement, the occurring precession moments are used to control damping moments and to store vibrational energy. Different damper characteristics are achieved by different induced precession. From almost zero torque output to high torque output, this damper has a huge spread. Next to the basic principal, in this paper an integration in the chassis, including a constructive proposal is shown. A conflict with high torque and high angular velocity leads to a special design. Moreover concepts to deal with all vehicle situations like yawing, rolling and pitching are shown.
2015-04-14
Journal Article
2015-01-1505
Ibrahim A. Badiru
Abstract Vehicle steering wheel pull is a condition experienced by customers where a constant torque at the steering wheel is required to maintain a straight path. Steering wheel pull may be accompanied by the secondary effects of steering wheel angle misalignment and vehicle thrust angle “dog-tracking.” EPS pull compensation is a feature that can automatically compensate vehicle steering wheel pull. This paper examines customer benefits, operating principles, effectiveness, and robustness of EPS pull compensation in vehicles. Vehicle road test data indicate EPS can correct a severe vehicle steering wheel pull. Using fundamental physics equations, an analysis tool is derived to support further investigation of steering wheel angle misalignment and vehicle thrust angle. The final section presents a designed experiment revealing parameters most influencing vehicle robustness to chassis and road characteristics.
2015-04-14
Journal Article
2015-01-1517
David Stalnaker, Ke-Jun Xie, Terence Wei
Abstract Tire manufacturers need to perform various types of testing to determine tire performance under representative vehicle load conditions. However, test results are influenced by a number of external variables other than tire construction. Vehicle load distribution and suspension properties are some of those external variables which can have a significant effect on tire wear rate and durability. Therefore, in order to measure real world tire performance in a controlled and repeatable manner, a representative vehicle and associated tire load conditions are needed. Laboratory or indoor tire testing offers many advantages over vehicle fleet testing. It provides a well-defined test environment and repeatable results without influence from external factors. Indoor testing has been largely developed around the process of simulating tire wear performance on a specific reference vehicle, including its specific weight distribution, suspension characteristics, and alignment.
2015-04-14
Technical Paper
2015-01-1516
Mohammed K Billal, Rizwan Basha, Anilkumar Nesarikar, Abdul Haiyum, Thomas Oery
Abstract Damages (fracture) in metals are caused by material degradation due to crack initiation and growth due to fatigue or dynamic loadings. The accurate and realistic modeling of an inelastic behavior of metals is essential for the solution of various problems occurring in engineering fields. Currently, various theories and failure models are available to predict the damage initiation and the growth in metals. In this paper, the failure of aluminum alloy is studied using progressive damage and failure material model using Abaqus explicit solver. This material model has the capability to predict the damage initiation due to the ductile and shear failure. After damage initiation, the material stiffness is degraded progressively according to the specified damage evolution response. The progressive damage models allow a smooth degradation of the material stiffness, in both quasi-static and dynamic situations.
2015-04-14
Technical Paper
2015-01-1518
Emmanuel O. Bolarinwa, Oluremi Olatunbosun
Abstract Three-dimensional (3D) Finite element (FE) tyre models have been widely used for tyre design, vehicle design and dynamic investigations. Such tyre models have the inherent advantage of covering a wide range of tyre modelling issues such as the detailed tyre geometry and material composition, in addition to an extensive coverage of tyre operational conditions such as the static preload, inflation pressure and driving speed. Although tyre vibration behaviour, in different frequency ranges are of general interest, both for the vehicle interior and exterior noise, the present study is limited to a frequency of 100 Hz which is prevalent in most road induced (Noise, Vibration, Harshness) NVH ride and handling problems. This study investigates tyre vibration behaviour using a proprietary FE code. Such investigation plays an important role in the study of vehicle dynamics.
2015-04-14
Technical Paper
2015-01-1513
Anudeep K. Bhoopalam, Kevin Kefauver
Abstract Indoor laboratory tire testing on flat belt machines and tire testing on the actual road yield different results. Testing on the machine offers the advantage of repeatability of test conditions, control of the environmental condition, and performance evaluation at extreme conditions. However, certain aspects of the road cannot be reproduced in the laboratory. It is thus essential to understand the connection between the machine and the road, as tires spend all their life on the road. This research, investigates the reasons for differences in tire performance on the test machine and the road. The first part of the paper presents a review on the differences between tire testing in the lab and on the road, and existing methods to account for differences in test surfaces.
2015-04-14
Technical Paper
2015-01-1512
Sairom Yoo, Md Salah Uddin, Hyeonu Heo, Jaehyung Ju, Doo Man Kim, Seok-Ju Choi
Abstract In an effort to develop tires with low rolling resistance, nonpneumatic tires (NPTs) with low viscoelastic energy loss materials are receiving more attention. For better design of NPTs on fuel efficiency, one may need to analyze rolling energy loss of NPT at a component level. The objective of this study is to develop a tool to quantify rolling energy loss and the corresponding internal heat generation of NPTs at a component level. For varying vehicle loads and rolling speeds, we suggest a thermo-mechanical model of an NPT with hexagonal cellular spokes and investigate temperature distribution of the NPT generated by hysteresis and convection loss into air. Using a hyper-viscoelastic material model developed from uniaxial (tensile and compression) tests and dynamic mechanical analysis (DMA), a thermo-mechanical model is developed by combining a longitudinal shear deformation induced hysteresis and a cooling procedure exposed to air.
2015-04-14
Technical Paper
2015-01-1515
Kwangwon Kim, Hyeonu Heo, Md Salah Uddin, Jaehyung Ju, Doo-Man Kim
Abstract Due to the relatively high freedom of selection of materials associated with a simple manufacturing method, a nonpneumatic tire (NPT) can be manufactured with a low viscoelastic energy loss material. A highly increasing demand to reduce greenhouse gases drives engineers to explore NPTs. NPTs consisting of flexible spokes and the shear band are still at an early stage of research and development. An optimization study of NPTs' geometry needs to be conducted, which is the objective of this paper. Parametric studies and design of experiments (DOE) of an NPT are conducted with a hyper-viscoelastic finite element (FE) model to determine the effects of three design variables on rolling resistance: the thickness of cellular spokes, the cell angle, and the shear band thickness. Considering vehicle load carrying capacity and riding comfort, ranges of vertical deflection between 18 and 20mm and contact pressure between 0.6 and 0.8MPa are selected as constraints for the optimization.
2015-04-14
Technical Paper
2015-01-1514
Deepak Tiwari, Japveer Arora, Rakesh Khanger
Abstract A typical wheel development process involves designing a wheel based on a defined set of criteria and parameters followed by verification on CAE. The virtual testing is followed by bench level and vehicle level testing post which the design is finalized for the wheel. This paper aims to establish the learning which was accomplished for one such development process. The entire wheel development process had to be analyzed from scratch to arrive at a countermeasure for the problem. This paper will not only establish the detailed analysis employed to determine the countermeasure but also highlight its significance for the future development proposals. The paper first establishes the failure which is followed by the detailed analysis to determine the type of failure, impact levels and the basic underlying conditions. This leads to a systematic approach of verification which encompasses the manufacturing process as well as the test methodology.
2015-04-14
Technical Paper
2015-01-1524
Ping Chen, Nan Xu, Konghui Guo, Rongsheng Liu
Abstract The tire lateral force is essential to the vehicle handling and stability under cornering. However, it is difficult for engineers to get the tire lateral force under high loading condition due to the limitation of loading ability for most tire test machine in the world. The widely used semi-empirical tire lateral force models are obtained by curve-fitting experiments data and thus unable to predict the load dependent lateral force. The objective of this paper is to predict the tire lateral force under high-load condition based on the low-load tire data. The nonlinear characteristics of the tire cornering stiffness with the load are greatly affected by the tire carcass compliance. In this paper, a theoretical tire lateral model was built by considering carcass complex deformation. Combined with the relationship between the half-length of the tire contact patch and the load, the non-linear characteristics of the tire cornering stiffness with load were obtained.
2015-04-14
Journal Article
2015-01-1520
Massimiliano Gobbi, Giampiero Mastinu, Federico Ballo, Giorgio Previati
Abstract A wheel able to measure the generalized forces at the hub of a race motorcycle has been developed and used. The wheel has a very limited mass. It is made from magnesium with a special structure to sense the forces and provide the required level of stiffness. The wheel has been tested both indoor for preliminary approval and on the track. The three forces and the three moments acting at the hub can be measured with a resolution of 1N and 0.3Nm respectively. A specifically programmed DSP (Digital Signal Processor) embedded in the sensor allows real-time acquisition and processing of the six signals of forces/torques components. The signals are sent via Bluetooth to an onboard receiver connected to the vehicle CAN (Controller Area Network) bus. Each signal is sampled at 200Hz. The wheel can be used to derive the actual tyre characteristics or to record the loads acting at the hub.
2015-04-14
Journal Article
2015-01-1521
Kanwar Bharat Singh, Srikanth Sivaramakrishnan
Abstract Tread depth, inflation pressure, tire temperature, and road surface condition are among the most notable factors that have a noticeable effect on the tire force and moment characteristics. They can vary significantly during the operation of a tire and can effectively modify tire (and thus vehicle) performance. This study presents details of an adaptive magic formula (MF) tire model capable of coping with changes to the tire operating condition. More specifically, extensions have been made to the magic formula expressions for tire cornering stiffness and peak grip level, to account for variations in the tire inflation pressure, load, tread-depth and temperature. As a next step, the benefits of using an adaptive tire model for vehicle control system applications is demonstrated through simulation studies for enhanced vehicle control systems using an adaptive tire model in comparison to traditional control systems based on a non-adaptive tire model with fixed model parameters.
2015-04-14
Technical Paper
2015-01-0159
Zhihui Tan, Zhenfu Chen, Xiaofei Pei, Jie Zhang, Xuexun Guo
Abstract Analogous to a vacuum boosted system, Electro-Hydraulic Braking System (EHB) is free from engine vacuum and supplies a braking force proportional to driver input. The independence of engine vacuum makes it especially suitable to be used in electric vehicles (EVs) and hybrid electric vehicles (HEVs). As a key component of EHB, master cylinder is driven by the pump rather than the vacuum booster. Even if the pump fails, the cylinder can also build proper pressure. Meanwhile, in order to maintain the pedal feeling, a pedal stroke simulator is applied in the system. In this paper, aiming at decreasing the size and cost of master cylinder and providing an ideal pedal feeling without compromise of performance, a new integrated master cylinder of EHB system is designed including two parts: master cylinder and pedal stroke simulator. The key components of the integrated master cylinder are motor pump, solenoid valves and composite springs.
2015-04-14
Technical Paper
2015-01-0216
Ping-Min Hsu, Ming Hung Li, Kuo-Ching Chang
Abstract This paper discusses noise filtering in an autonomous emergency braking (AEB) system with a sensor fusion between a millimeter wave (MMW) radar and a camera. Three kinds of noise, namely twice harmonic noise, ground noise, and specular reflection noise, are then filtered. The former is caused by the reflection of a radar wave between a target object and the MMW radar; therefore, one of the sensing distances would be twice as longer as one of others. An object featuring this characteristic is treated as the noise and filtered. Next, detecting a ground metal as the target object generates the second noise with a focus of car-like objects. That is, an object-with the sensing distance from the MMW radar being smaller than that from the camera by a threshold value-is taken as the ground metal noise and ignored. Moreover, the third noise happens when there is a radar wave reflection between an object and its surroundings.
2015-04-14
Technical Paper
2015-01-1417
Jeffrey Muttart
Abstract Controlled studies identified several factors that influence drivers' swerving when responding to in an emergency situation. Specifically, driver age, time-to-contact, amplitude of the steering action (steer within lane or swerving into the next lane), distraction, fatigue, natural lighting and available buffer space were identified as factors that influence steering behaviors. The goal of the current research was to identify the extent to which each factor changed swerving performances of drivers who were faced with a crash or near crash. Results from crashes and near crashes were obtained from the InSight (SHRP-2) naturalistic driving study. The results from the controlled studies and the results from the naturalistic driving research were consistent in many ways. Drivers engaged in a visual-manual secondary task were much younger than were the drivers who had no distracting secondary task.
2015-04-14
Technical Paper
2015-01-1414
Jitendra Shah, Mohamed Benmimoun
Abstract The focus of this paper is the threat assessment of perceived threat by drivers in collision avoidance situations. The understanding of the decision making process with regards to the initiation of a driver intervention is a crucial step to gain insight into driver's steering and braking behavior in case of an imminent threat (rear-end collision). Hence a study with various test subjects and a test vehicle has been conducted. The study has helped to understand how drivers behave in potential rear-end collision situations arising from the traffic situation (e.g. start of a traffic jam). This information is of major importance for designing autonomous collision avoidance systems and an important step towards autonomous driving. Autonomous driving in vehicles require system interventions to be initiated as early and safely as possible in order to avoid the collision and to avoid unstable vehicle dynamics situations.
2015-04-14
Technical Paper
2015-01-1328
Da-Wei Gao, Xing-Xing Huang, Jun Xu, Song-Lin Zheng
Abstract Taking a domestic brand car as example, this paper is about how to find out a three-point nonlinear stiffness characteristic curve which can meet the requirements of variable stiffness and three-load condition. The new coil spring gives the passive suspension a lot of improvements in riding and safety, changing the nonlinear stiffness characteristic from weak to strong. This paper summarizes the optimization design method for the rear suspension coil spring, which includes the fitting of ideal stiffness characteristic curve, quantitative method for figuring out how the change of vehicle load influences the load on rear suspension axle, the design method of variable stiffness coil spring which corresponds to the change of vehicle load. A new kind of modified ideal point solution for building the objective function was also put forward.
2015-04-14
Journal Article
2015-01-1314
Max Sardou, Patricia Djomseu
Abstract SARDOU SAS has developed highly stressed composites parts for 35 years. SARDOU SAS and QUALITY INDUSTRIAL PRODUCT invented composite coils springs in 2002. Developing composite coils springs, we have faced a big challenge, how to increase the short life expectancy of this highly stressed structure? We have identified that the weak point, in composite coils springs, is its epoxy matrix. In fact, during heavy loading, the matrix undergoes micro cracks. Then, during fatigue, micro cracks propagate and merge, transforming the matrix into a fine powder. The composite coil suspension springs, using, classic epoxy, where ruined after only 100,000 cycles in the best cases. The fact to integrate “functionalized silica aggregates”, in the matrix, enable the springs to exceed 1,000,000 cycles, with the same spring design. In addition, the spring stiffness has increased by 6% and the thermal set has reduced by 1.6%.
2015-04-14
Technical Paper
2015-01-1356
Atishay Jain
Abstract Conventional motorcycle swingarm design includes steel tubing and sheet metal structures. Conventional swingarm are inherently over-designed as their design comprises of tubular structures of same cross section through the entire length of the swingarm, whereas the stress induced varies along the length (maximum near the frame pivot). An aluminum alloy swingarm design even when subjected to casting manufacturing constraints, has the potential for better material layout and weight minimization. But obtaining an ideal material layout for maximum performance can be a challenge as it requires a number of time consuming design iteration cycles. This paper aims to use concept based design methodology for design of aluminum alloy swing arm by application of topology optimization techniques to meet styling and structural targets and thus, obtain an end user product.
2015-04-14
Technical Paper
2015-01-1347
Fiona Ruel, Pierre-Olivier Santacreu, Saghi Saedlou, Guillaume Badinier, Jean Herbelin
Abstract In order to meet new environmental regulations (i.e. mass of CO2 rejected in the atmosphere per km), car manufacturers are looking for new solutions to lighten chassis and structural parts in cars. High strength steels formed by hot stamping have proved to be good candidates for achieving better in-use performances together with a lighter structure. In particular, the martensitic stainless steel MaX fulfils the industrial targets for chassis parts in terms of mechanical and fatigue properties. For instance, from a cold formed baseline made of 600 MPa carbon steel, a 50 % mass reduction can be expected with a hot stamped suspension arm made of MaX and included a new clamshell design. However, those parts are often made of a complex assembly of different materials (high strength steels, aluminium and cast iron among others) which are subjected to aggressive environments in service. Therefore galvanic corrosion of those complex assemblies has to be evaluated.
2015-04-14
Technical Paper
2015-01-1345
Srinivas Kurna, Arpit Mathur, Sandeep Sharma
Abstract In commercial vehicle, Leaf Spring design is an important milestone during product design and development. Leaf springs are the most popular designs having multiple leaves in contact with each other and show hysteresis behavior when loaded and unloaded. Commonly used methods for evaluation of leaf spring strength like endurance trials on field and Rig testing are time consuming and costly. On the other hand, virtual testing methods for strength and stiffness evaluation give useful information early in the design cycle and save considerable time and cost. They give flexibility to evaluate multiple design options and accommodate any design change early in development cycle. A study has been done in Volvo-Eicher to correlate Rig result with Finite Element Analysis (FEA) simulation result of Multi-stage Suspension Leaf Spring, entirely through Finite Element Analysis route.
2015-04-14
Technical Paper
2015-01-1464
Qiang Chen, Miao Lin, Bing Dai, Jiguang Chen
Abstract In China, nearly 25% of traffic fatalities are pedestrians. To avoid those fatalities in the future, rapid development of countermeasures within both passive and active safety is under way, one of which is autonomous braking to avoid pedestrian crashes. The objective of this work was to describe typical accident scenarios for pedestrian accidents in China. In-depth accident analysis was conducted to support development of test procedures for assessing Autonomous Emergency Braking (AEB) systems. Beyond that, this study also aims for estimating the mitigation of potential crash severity by AEB systems. The China In-depth Accident Study (CIDAS) database was searched from 2011 to 2014 for pedestrian accidents. A total of 358 pedestrian accidents were collected from the on-site in-depth investigation in the first phase of CIDAS project (2011-2014).
2015-04-14
Technical Paper
2015-01-0689
R. Rajendran, G. Ramanjaneyulu, T R Tamilarasan, Vladimir I. Semenov
Abstract Cryogenic treatment has a good potential to significantly increase the service life of automotive components, where friction and wear are the major factors in their operation leading to failure. Cryogenic treatment changes the surface as well as the core properties of the component in comparison with other treatments. It has significant improvement in wear and toughness. Numerous studies have been conducted on cryogenic treatment of steels and tool steels showing significant improvements in wear resistance, only minimal work has been done in cast irons. In this study, the effect of cryogenic treatment on the wear resistance, hardness, tensile strength, toughness and microstructure of spheroidal graphite iron was assessed. The deep cryogenic treatment was carried out at 87K for 12h and annealed in the chamber itself. The samples were tempered at 473K for 1 h.
2015-04-14
Technical Paper
2015-01-0591
Karan R. Khanse, Eric Pierce, Michael Ng, Saied Taheri
Abstract Outdoor objective evaluations form an important part of both tire and vehicle design process since they validate the design parameters through actual tests and can provide insight into the functional performances associated with the vehicle. Even with the industry focused towards developing simulation models, their need cannot be completely eliminated as they form the basis for approving the performance predictions of any newly developed model. An objective test was conducted to measure the ABS performance as part of validation of a tire simulation design tool. A sample vehicle and a set of tires were used to perform the tests- on a road with known profile. These specific vehicle and tire sets were selected due to the availability of the vehicle parameters, tire parameters and the ABS control logic. A test matrix was generated based on the validation requirements.
Viewing 61 to 90 of 10218

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