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Viewing 1 to 30 of 7721
2015-09-29
Technical Paper
2015-01-2728
Paul C. Cain
OEM benefit: Vehicle manufacturers desire continuous feedback in monitoring key safety sub-assemblies. In this application, engineers are calculating the remaining brake pad life by monitoring the current thickness of the brake pad friction material. This information is used in scheduling preventative maintenance activities and avoiding safety incidents. Unplanned machine down time and field repair costs in earthmoving equipment is cost prohibitive. This technology allows OEM's to have high confidence, continuous feedback on this critical vehicle safety feature avoiding expensive, unplanned repairs and improving field "up time" performance. Application challenge: Developing a reliable linear position sensor that is suitable for continuous monitoring of brake pad material thickness in a high pressure, high temperature, high vibration and contaminated environments typical of large construction (earthmoving) vehicles.
2015-09-29
Technical Paper
2015-01-2901
Shaoyun Sun, Genghua Liao, Qiang Fu, Kelong Lu, Jing Zhao, Zhengzheng Li, Jiaquan Chen, Guang Shi, Sacha Jelic, Bo Li
Trucks are designed to carry heavy load, which implies high demanding design criteria for save operation. Heavy load means a lot of energy is needed to displace the load. During a stop, the kinetic energy is transferred into heat, which can be problematic in case of excessive proportions and/or when the heat cannot be removed from the system properly. The brake system therefore needs to be designed such to be able to absorb large of amount of heat and transfer the heat out of its system by either convection, conduction and/or radiation. All three heat transfer modes play an important role since the drum brakes of trucks are not much exposed to external airflow, a significant difference from disk brakes of passenger cars analyzed in previous studies. This makes it a complex heat transfer problem which is not easy to understand. Numerical methods provide insight by visualization of the different heat transfer modes.
2015-09-29
Technical Paper
2015-01-2766
Sai Venkatesh Muravaneni, Egalaivan Srinivasan, Jagankumar Mari
Steering wheel being the most used tactile point in a vehicle, its feel and response is an important factor based on which the vehicle quality is judged. Engineering the right feel and response into the system requires knowledge of the objective parameters that relate to the driver perception. Extensive correlation work has been done in the past pertaining to passenger cars, but the driver requirements for commercial vehicles vary significantly. Often it becomes difficult to match the right parameters to the steering feel experienced by the drivers since most of the standard units used to describe them are of zero or first order parameters. Analyzing the second order parameters gave a better method to reason driver related feel. Also, each subjective attribute was fragmented into sub-attributes to identify the reason for such a rating resulting in the identification of the major subjective parameters affecting driver ratings.
2015-09-29
Technical Paper
2015-01-2745
Florian Bauer, Jan Fleischhacker
A Hardware-in-the-Loop (HiL) system for Electronic Control Units (ECU) of electro-pneumatic brake systems is presented. The HiL system runs a real-time capable vehicle model comprising of both the vehicle dynamics and the electro-pneumatic brake system. The dynamic behaviour of the vehicle can be simulated either by a real-time multi-body vehicle model or by a simpler system dynamic (double-track) model. To assess the quality of the system dynamic vehicle model, it was compared to the multi-body vehicle model which was validated with comprehensive experimental results. Discrepancies can be seen for highly unsteady manoeuvres. Reasons for these discrepancies caused by the modelling topology of the system dynamic vehicle model will be given. In order to simulate the electro-pneumatic brake system, a real-time model has been developed and validated. The different topologies of brake systems can be assembled from components and integrated into the vehicle model.
2015-09-29
Technical Paper
2015-01-2753
Xiujian Yang, Ruocheng Zhu, Jin Gao
Tractor semi-trailer as a type of widely-used heavy duty freight vehicle is with relatively poor handling and lateral stability and is easy to fall into a lateral instability such as jackknife, trailer swing even causing an fatal accident. In this paper, attention is concentrated on a novel design concept for a tractor semi-trailer vehicle to improve the handling and lateral stability performances comprehensively by optimizing the whole vehicle arrangement and relevant design parameters. According to the previous public reports, the indexes such as Load Transfer Ratio(LTR), Static Rollover Threshold (SRT), Rearward Amplification Ratio (RWA) and Ratio of Yaw Rate (RYR) as very effective measures are often used to evaluate the handling and stability performances for a tractor-trailer vehicle. However, each of those indexes works individually and only focuses on a certain aspect with less relations to others.
2015-09-29
Technical Paper
2015-01-2833
Ashley L. Dunn, Brian Boggess, Nicholas Eiselstein, Michael Dorohoff, Harold Ralston
Brake chamber construction allows for a finite stroke for pushrods during brake application. As such, the Federal Motor Carrier Safety Regulations (FMCSRs) mandate maximum allowable strokes for the various chamber types and sizing. Brake strokes are often measured during compliance inspections and post-accident investigations in order to assess vehicle braking performance and/or capability. A number of forensic studies have been performed, and their results published, regarding the effect of brake stroke on braking force and heavy truck stopping performance. All of the studies have relied on a brake supply pressure in the neighborhood of 100 pounds per square inch (psi). When brake strokes are measured in the field, following the Commercial Vehicle Safety Alliance (CVSA) procedure, the application pressure is prescribed to be maintained between 90 and 100 psi.
2015-09-29
Technical Paper
2015-01-2872
Massimiliano Ruggeri, Andrea Cervesato, Carlo Ferraresi
Performance requests and machine automation, in conjunction with new regulations for agriculture, earthmoving and construction machines, represent today the most difficult challenge for machine designers and researchers. Machine control systems complexity and functional safety regulation compliance, are the most complex requirements to deal with in new machines design. The paper describes a steering system design, of a 6 wheels agricultural front articulated self-propelled machine, that must comply with new regulations in terms of functional safety. The vehicle steering is driven by an electro-hydraulic system, totally controlled using by wire electronics; the rear wheels are independently steering and controlled. This architecture requires a too high functional safety performance level.
2015-09-29
Technical Paper
2015-01-2733
Samraj Benedicts, Vivek Seshan
This paper is a study of reaction forces and its effects on the chassis due to rear idler position. Rubber Track layouts and traction have been focus of most research work, here we study the effect of Rear Idler position on layout and chassis structure through simulated analysis. An agriculture paddy combine harvester with rubber track is considered for the purpose of this work. Firstly the complete undercarriage is modeled in 3D using Creo and exported to Pro Mechanica for simulation. The real time forces, constraints were applied and the results were correlated to actual field results. The simulations were optimized through several iterations to match the field test results. The simulation and field test results show good agreement to the forces and constrains applied for simulation. Secondly the model was simplified for relative analysis and simulated for different rear idler positions with alternate tensioning methods.
2015-09-29
Technical Paper
2015-01-2756
Basaran Ozmen, Mehmet Bakir, Murat Siktas, Serter Atamer, Roman Teutsch
Securing the desired durability of suspension components is one of the most important topics for the vehicle designers because these components undergo multiaxial variable amplitude loading in the vehicle. Leaf springs are essential for the suspension system of trucks and should be considered as a security relevant part in the product development phase. In order to guide the engineers in the design and testing department, a simulation method was developed as explained in the paper “Bakir, M., Siktas, M., and Atamer, S., "Comprehensive Durability Assessment of Leaf Springs with CAE Methods," SAE Technical Paper 2014-01-2297, 2014”. In this new study, the main aim is to present the validation of this newly developed CAE method for the durability of leaf springs depending on the results from testing and measurement in the rough road and test bench.
2015-09-29
Technical Paper
2015-01-2726
Balaji Lomada, N G Rajakumar, V Vijaykumar
Commercial vehicles have steering system with one or more steering links (draglinks) connecting the steering gear box pitman arm and front axle steering arm. In case of twin steer vehicles, intermediate pivotal arm is used to transfer the motion proportionately between the two front axles. Intermediate pivotal arm is also used in some longer front over-hang vehicles to overcome their packaging constraints and to optimize the mechanical leverage. The pivot shaft is a mechanical part of the intermediate pivot arm assembly which is subjected to forces and bending moments generated by draglinks. In this work, study has been carried out on premature failure of the pivot shaft in city bus application model (Entry + 1 step). Metallurgical analysis of failed part indicated the failure to be due to fatigue. Pivot shaft was tested in rig with similar load conditions in order to replicate the failure. The failure mode and location of both, tested as well as field failure samples were identical.
2015-09-29
Technical Paper
2015-01-2751
Igor Baseski, Kenneth Norman, David Ryan, Stefanie Stahara
At the request of the U.S. Army’s Tank Automotive Command (TACOM) laboratory facilities have been built to measure the suspension and mass parameters of the U.S. Army and civilian wheeled vehicles. This is part of an ongoing effort to model and predict vehicle dynamic behavior, so as to build vehicles that are less prone to roll over, have better handling stability, and perform better in rough terrain. These new machines, called the Suspension Parameter Identification and Evaluation Rig (SPIdER) and Vehicle Inertial Properties Evaluation Rig (VIPER), are part of a set of large test devices at TACOM’s facility in Warren, MI. The SPIdER machine operates by holding the vehicle body fixed using a variety of clamps and chains that are arranged specifically for each vehicle. Hydraulic cylinders are used to move an “axle frame” in bounce or roll under each axle being tested. Combinations of bounce and roll can be used, which could be used to simulate roll under different loading conditions.
2015-09-29
Technical Paper
2015-01-2721
Balaji Lomada, R. Jayaganthan, V. Vijaykumar
Commercial vehicle industry is presently striving towards development of buses with enhanced passenger safety and comfort. This calls for additional components and aggregates that eventually lead to increase in the overall length of the bus. Usually, steering system of longer wheel base and longer front overhang (FOH) vehicles have multiple linkages such as bevel box or relay arrangement instead of direct draglink because of packaging and design constraints. In this work, an attempt has been made to design the steering system for longer FOH vehicles with direct draglink arrangement. Here, single draglink is packaged and designed with high strength tube material (Yield stress is Min. 700 MPa) by optimising the steering geometry. Design optimisation of steering geometry is carried out ensuring existing level steering performance without compromising vehicle dynamic parameters. The CAE-MBD analysis has been done to compare the performance of existing and proposed steering system.
2015-09-29
Technical Paper
2015-01-2742
Linlin Wang, Hongyu Zheng, Changfu Zong, Yuchao Chen
Combining with the practical development of heavy duty vehicle, it is playing a more and more crucial role in the transportation industry due to its high fleet efficiency and fuel economy. The heavy duty vehicle’s mass varies significantly from trip to trip. The mass nonlinear fluctuation would worsen the brake performance, as the same brake pedal stroke produces larger and smaller acceleration than the ideal value, making it difficult for the unexperienced drivers to manipulate vehicles especially on the critical maneuver such as sideslip, rollover and swing etc. Accurate mass information is instrumental when designing electronic brake system controller to optimize the relevant braking force distribution. Directing at the above arguments, the paper proposes two approaches to estimate vehicle mass. One is estimating vehicle mass during braking process, the other is estimating the vehicle mass during acceleration.
2015-09-29
Technical Paper
2015-01-2841
Hongyu Zheng, Shenao Ma
In order to adapt to the quickening rhythm of the society and satisfy human's higher performance requirements of comfort and safety, the kinds of brake assist system has become more and more, smooth transformation of man-machine control is very important for the driver assistance system. At the same time, Brake-by-wire cancels the traditional mechanical connection of the system, the ECU to perceive the driver’s braking intention and send the instructions to the corresponding actuator. Thus, it is necessary to identify the driver's braking intention for Brake-By-wire system and the smooth transition of man-machine mode. This paper establishes recognition model for the driver’s braking intention recognition, which is based on analyzing and summarizing existing research of driver intention recognition.
2015-09-29
Technical Paper
2015-01-2842
Hongyu Zheng, Jinghuan Hu, Shenao Ma
By reviewing the previous research, we put the stability of tractor trailer into two categories, roll stability and yaw stability, and identify the indicators of two kinds of stability. Further we came up with three normal stability loss situations. They are roll-over, jack-knife and trailer swing. This work extends previous tractor trailer stability research from roll stability to roll/yaw stability; moreover, we set up the object of our investigation, that is enhance the tractor-trailer stability by reducing the occurrence of three stability loss. Based on the tractor semi-trailer model built in MATLAB, we made research on how the vehicle parameters affect the entire vehicle dynamic stability. In this section, we modified the model by changing a more sophisticated tire model. This work will benefit the commercial vehicle designer in the early stage of vehicle designing.
2015-09-29
Technical Paper
2015-01-2725
Amine Nhila, Daniel E. Williams
Over the years, steering systems have evolved from simple manual steering in the early car models to hydraulic power steering in the middle of the 20th century, and eventually to today’s systems where electric power steering is becoming more prevalent, specifically in light vehicles such as passenger cars. However, due to their relative low power density, electrical steering systems did not gain much traction in heavy vehicles, at least not as the sole source of power assistance. As a result of their higher power density, hydraulic power steering systems remain the main solution for steering heavy vehicles. Nonetheless, when these systems were first designed energy savings, and CO2 emissions were not a major concern while fuel prices were relatively low. Consequently, today’s state-of-the-art steering systems are not as efficient as they can be, and thus cause higher emissions.
2015-09-29
Technical Paper
2015-01-2760
Andrei Izmailov, Vladimir Shevtsov, Alexandr Lavrov, Zahid Godzhaev, Vladimir Pryadkin
Maximum pressure is an essential parameter determining the degree of environmental impact of pneumatic tractor wheels on soils. The authors of the paper offer a method for determining and adjusting maximum pressure of a pneumatic tractor wheels on the supporting surface. The paper contains an analysis of the variation of maximum pressure on soils for various values of internal tire pressure and vertical load on a wheel. The above method allows parameters for systems of monitoring and adjustment of maximum pressure on soils to be set up by measuring tire flexure and adjusting it through changing the internal air pressure.
2015-09-29
Technical Paper
2015-01-2801
Yuandong Liu, Gangfeng Tan, Xuexun Guo, Li Zhou, Wenbin Liu, Zhiqiang Hu, Kangping Ji, Binyu Mei
The hydraulic retarder, which is an important auxiliary brake, has been widely used in heavy vehicles. Under the non-braking working condition, the air resistance torque in the working chamber, which is formed for the rotor of hydraulic retarder stirs the air, causes pumping loss. This research designs a new hydraulic retarder, which the helium is charged into working chamber through closed loop gas system under non-braking working condition, can reduce the parasitic power loss of transmission system. First, under non-braking working condition, the resistance characteristics are analyzed based on the hydraulic retarder pumping model; Then, considering some parameters, such as the volume of chambers and the initial gas pressure, the working chamber gas charge model is established, and the transient gas charge characteristics are also researched under non-braking working condition.
2015-09-29
Technical Paper
2015-01-2823
Uriy Usinin, Sergey . Gladyshev, Maxim Grigoryev, Alexander Shishkov, Evgeny Belousov, A..M. Zhuravlev, Anton Bychkov, Dmitry Sychev
It is offered the traction electric drive of the active trailer for transportation long pipes with big diameter. The active trailers are necessary at a building of oil pipe lines and gas-mains in trackless conditions and marshland. Due to the electric drive, the pass ability of trailer is sharply increased on marshland conditions and drive control of trailer is facilitated. The specified attractive qualities appear, if wheels of the trailer are driven by individual electric motors, and the mechanical kinematic circuit of drive contains only one-stage. The power of the electric drive will take 20-25 % from rated power of the basic trailer drive, and the electric drives have expanded speed regulation range. For decision of such a task, it is used the method of two-diapason regulation of the torque. But such approach demands application of electric machines with the big factor of an overload on the torque (up to 10 times of the nominal torque).
2015-09-29
Technical Paper
2015-01-2835
Sughosh J. Rao, Mohamed Kamel Salaani, Devin Elsasser, Frank Barickman, Joshua L. Every, Dennis A. Guenther
This study was performed to showcase the possible applications of the Hardware in the Loop (HIL) simulation environment developed at The National Highway Traffic Safety Administration (NHTSA) Vehicle Research and Test Center (VRTC) research lab, to test heavy truck Electronic Stability Control (ESC) systems. In this study, the HIL simulation environment was used to recreate (an interpretation of) an actual accident scenario involving a single tractor-trailer. The scenario was then simulated with and without an ESC system to investigate the advantages afforded by the ESC system, if any. An acutal crash scenario reported in the Large Truck Crash Causation Survey (LTCCS), involving a single tractor-trailer was chosen. The crash scenario was interpretted as a path following problem and three possible driver intended paths were developed from the accident scene data. A path following algorithm was implemented in Simulink to simulate these paths.
2015-09-29
Technical Paper
2015-01-2839
Rangaraj Ramanan Durai, Ashok Thirupathi, Mohith Krishna Shetty, Dilip Joy Mampilly
In this paper Longitudinal Force Slip (LFS) controller will be designed for controlling the traction force in each wheel when Rock Crawl Scenario prevails for commercial vehicles working in Off-Road condition. During Rock crawling the wheels can have more longitudinal slip than lateral slip. Slip is caused by relative movement of tires with the rock. PI controller (Longitudinal Force Controller) will be designed in order to stabilize the traction force on individual wheels. Individual Lateral and Longitudinal force will be calculated for each wheel from Tire modeling. Optimal longitudinal force will be determined based on fuzzy model with the help of determined Mue. The designed LFS controller which controls the individual traction force by applying active braking. Active braking on individual wheel will be realized with the hydraulic system associated with Vehicle Stability Control ECU (VSC - ECU). Optimal engine torque will be calculated based on driver pedal request.
2015-09-29
Journal Article
2015-01-2731
Xingjian Gu, Guoying Chen, Changfu Zong
As a new form of electric vehicle, four-wheel-independent electric vehicle inherits a large number of advantages of in-wheel motor drive electric vehicle for the huge difference from the traditional vehicle in mechanical structure. The vehicle is driven by four in-wheel motors and the steering system is controlled by X-By-Wire (XBW). Steering system is liberated from traditional mechanical steering mechanism and forms an advanced vehicle with all-wheel independent driving, braking and steering. Compared with conventional vehicles, it has more controllable degrees of freedom. The integrated vehicle dynamics control systems help to achieve the steering, driving and braking coordinated control and improve the vehicle’s handling stability and safety. In order to solve the problem of lacking of vehicle state information in the integrated control, some methods are used to estimate the vehicle state of four-wheel-independent electric vehicles with XBW.
2015-09-29
Technical Paper
2015-01-2761
Boris Belousov, Tatiana I. Ksenevich, Sergei Naumov, Vitalii Stepnov, Anna Klimachkova
An electro-hydraulic servo system makes the basis for a mechatronic locomotion module (LM) and for a complex comprising an LM and an undercarriage of a vehicle. The servo system of the wheel module/LM complex is a combination of the information and power channels of the electro-hydraulic wheel drive within the steering system. A combination of the servo systems makes up a complex of servo systems of the steering system of the multi axis wheel mover of the vehicle. Theoretical and experimental studies of the functioning all-wheel steering were aimed on substantiation the rational algorithmic maintenance of the automatic control system. The results of the study allowed formulating the basic principles of designing and calculating the functionality algorithms for the steering system of the complex of mechatronic modules of the multi-axis vehicle.
2015-09-29
Technical Paper
2015-01-2763
S. F. Rahaman, Somenath Chatterjee
Abstract Steering pull during high speed braking of heavy commercial vehicles possesses a potential danger to the occupants. Even with negligible wheel-to-wheel brake torque variation, steering pull during the high speed braking has been observed. If the steering pull (i.e. steering rotation) is forcibly held at zero degree during high speed braking, the phenomena called axle twist, wheel turn and shock absorber deflection arise. In this work the data have been collected on the mentioned measures with an intention to develop a mathematical model which uses real time data, coming from feedback mechanism to predict the values of the measures in coming moments in order to aid steering system to ‘auto-correct’. Driven by the intention, ‘Time Series Analysis’, a well-known statistical methodology, has been explored to see how suitable it is in building the kind of model.
2015-09-27
Technical Paper
2015-01-2690
Joo Sang Park
This paper introduce several practical cases to cure the squeal noise by investigating pad unstable behaviour and self-excited vibration, and propose frequency guide lines for better noise performance. These guide lines are very useful for designers especially at the initial design stage. By using historical DOE, practical frequency guide lines will be proposed to achieve better noise performance at the initial design stage by using historical database analysis. This study has some limitations that the guide lines are available for disc. It will be further study for other brake components. In conclusion, the practical guide lines for robust disc design will be proposed after analyzing a pad unstable behaviour and disc self-excited vibration during squeal by theoretical , numerical and experimental approach. Finally the guide lines is validated by statistical approach by reviewing historical DOE for various brake systems.
2015-09-27
Technical Paper
2015-01-2674
Dragan Aleksendric, Velimir Cirovic, Dusan Smiljanic
Customer perception of brake pedal feel quality, depends on both the customer's subjective judgment of quality and the actual build quality of the brake system. The brake performance stability represents an important aspect of a vehicle performance and its quality of use. This stability is needed especially in brake by wire system and braking system with regenerative braking. In order to provide stable braked pedal feel i.e. consistent the brake performance against the brake pedal travel, the model of the brake performance versus the brake pedal travel needs to be established. In this paper new hybrid neuro-genetic optimization model was developed for dynamic control and optimization of the disc brake performance during a braking cycle versus the brake pedal travel. Based on such model, the brake performance optimization of the passenger car has been provided against the brake pedal travel.
2015-09-27
Technical Paper
2015-01-2685
Diego Masotti, Patric Neis, Ney Ferreira, Kássio Gomes, Jean Poletto, Luciano Matozo
The present work presents evaluation of the sliding surface morphology of brake pads during stick-slip process. For doing that, a brake friction material was subjected to slide against a brake disc under conditions favorable to produce stick-slip phenomenon. The experiments were conducted in a laboratory-scale tribometer, which was especially designed to test brake pads used in vehicle. Optical microscope images of the material’s surface were obtained at different stages of the braking test. These images were post-processed in appropriate computational software and by means of the segmentation technique the real contact area, size and amount of contact plateaus related to the brake pad surface were estimated. Coefficient of friction resulting from the tests was measured and it is also discussed throughout this paper.
2015-09-27
Technical Paper
2015-01-2666
Scott Lambert
The Global Brake Safety Council sees an increase in disc brake pads that are prematurely replaced before the end of the friction lining life cycle, due to: Rust related issues such as separation of friction lining from the disc brake shoe Fluctuation in critical dimensions A leading cause for both issues is the use of mill scale steel, or ‘black steel’ (non-pickled and oiled). In the North American aftermarket, as there are little or no steel specifications for disc brake shoes, black steel is increasingly used. GBSC conducted research of discarded disc brake pads from job-shops and engaged in discussions with metallurgists, major pad manufacturers and OE brake foundation engineers to identify root causes of premature pad replacement and the effects of black steel used for disc brake shoe manufacturing. Mill scale is embedded in and around the bond line of the friction lining and the disc brake shoe, causing a weaker bond, susceptible to rust jacking.
2015-09-27
Technical Paper
2015-01-2696
Shuichi Okada
We had developed Electric Servo Brake System, which can control brake pressure accurately with a DC motor according to brake pedal force. Therefore, the system attains quality brake feeling while reflecting intentions of a driver. By the way, "Build-up" is characteristics that brake effectiveness increases in accordance with the deceleration of the vehicle, which is recognized as brake feeling with a sense of security as not to elongate an expected braking distance at a downhill road due to large-capacity brake pad such as sports car and large vehicles. Then, we have applied the optical characteristic control to Hybrid vehicles with Electric Servo Brake System by means of brake pressure control and regeneration brake. Hereby, we confirmed that the control gives a driver the sense of security and the reduction of pedal load on the further stepping-on of the pedal.
2015-09-27
Technical Paper
2015-01-2692
Giulia Garello, Niccolò Patron, Pietro Buonfico, Luca Martinotto
Nature of braking friction is extremely complex and a deeper understanding of the physical mechanisms that govern the energy dissipation at the interface of friction pair is an important tool to create an even deeper knowledge of tribological behavior of friction material. Friction brakes need to transform kinetic energy into heat: a complete knowledge of thermal effects during this process in every brake component is an essential part of brake design. As referred to brake pads, the analysis of dyno testing data highlighted experimental evidences related to thermo-mechanical effects, such as the different wear resistance capabilities of material classes (NAO and Low Steel). Tribological characteristics are not constant under all testing conditions and they strongly depend on temperature being the direct consequence of kinetic energy dissipation. The aim of this work is to explain the relation between wear and energy for different type of friction materials.
Viewing 1 to 30 of 7721