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2015-10-07
Magazine
Tearing down the global barriers Steering systems are becoming increasingly sophisticated, as Ian Adcock discovers when talking to the men leading Nexteer's European expansion €1.1 billion worth of Bentley luxury Bentley's Bentayga is the first in a new generation of luxury cross-overs. Ian Adcock reveals its engineering secrets Goal: "virtual" perfection Should simulations be 100% accurate?
2015-10-06
WIP Standard
J1802/1
This SAE Recommended Practice contains the reference information for SAE J1802.
2015-10-05
WIP Standard
J1615
Male pipe threads, including male dryseal pipe threads, when made into assemblies or installed into ports, will generally leak if not covered with a sealant. This SAE Recommended Practice is intended as a guide to assist designers and/or users in the selection and application of various types of thread sealants. The designers and users must make a systematic review of each type and application and then select the sealant to fulfill the requirements of the application. The following are general guidelines and are not necessarily a complete list.
2015-10-05
WIP Standard
J1131
This SAE Standard is intended to establish uniform methods of testing SAE J844 tubing and fitting assemblies as used in automotive air brake systems. This document also establishes minimum qualifications for tensile and pressure capabilities, vibrational durability under cyclic temperatures, serviceability, and fitting compatibility requirements. The specific tests and performance criteria applicable to the tubing are set forth in SAE J844. NOTE--The test values contained in this document are for test purposes only. For environmental and usage limitations see SAE J844.Fittings--A type of fitting for use with SAE J844 nonmetallic tubing is included in SAE J246; however, it is not intended to restrict or preclude the use of other designs of fittings that comply with this document.
2015-10-02
WIP Standard
J3111
The scope of this recommended practice is to establish definitions and recommended methods for the measurement of lateral run-out and disc thickness variation in the laboratory and vehicle for passenger cars and light duty trucks up to 4546 kg gross vehicle weight. This recommended practice will breakdown the instrumentation (sensors and sizes), test setup, and data processing.
2015-10-02
WIP Standard
AIR4905A
The purpose of this document is to present general considerations for the design and use of aircraft wheel chocks. The design and use of aircraft wheel chocks is a good deal more complicated than it may appear at first glance.
2015-09-29
Technical Paper
2015-01-2726
Balaji Lomada, N G Rajakumar, V Vijaykumar
Abstract Commercial vehicles have steering systems with one or more steering links connecting the steering gear box pitman arm and front axle steering arm. In case of twin steer vehicles, intermediate pivot arm is used to transfer the motion proportionately between the two front axles. Intermediate pivot 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 upon which pivot arm can swivel in one axis. Steering forces transferred through the drag links generates resultant forces and bending moments on the pivot shaft. 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.
2015-09-29
Technical Paper
2015-01-2724
Peiwen Mi, Guoying Chen
Abstract Electric Power Steering System (EPS) can directly provide auxiliary steering torque via a motor. The motor and the reducer in mechanical system will make the friction torque in steering system larger, as a result, the ability of steering returning will be reduced. Therefore, during the design of EPS system control strategy, an extra active return-to-middle control strategy is needed. For the fact that most of the low-end vehicles equipped with EPS system do not have a steering wheel angle sensor, a control strategy has to work without the datum of steering wheel angle. This paper proposes an active return-to-middle control method without steering wheel angle sensor, based on the estimated aligning torque which is converted to the pinion, and expounds how to determine the steering system current motion state in detail. This control method will work just during the turning condition, so it has no effect on the EPS basic assist characteristics.
2015-09-29
Technical Paper
2015-01-2722
Sundarram Arunachalam, Ramprabhu Kannan, Nagarajan Gopikannan, Jayaramareddy Sekar
Abstract With advancement of technology, better safety and higher vehicle reliability is primary requirement of end customer especially in public transportation. Hence there exist challenges in design and development of steering system for long haulage and tipper application. In the steering system, track rod is used to steer both the front tyre under different operating condition assisted by power steering system. This paper deals with the failures observed on track rod in long haulage and tipper application with loading conditions. Also the methodology adapted to resolve the field failures.
2015-09-29
Technical Paper
2015-01-2723
Yaning Han, Hongyu Zheng, Ying Wan, Changfu Zong
Abstract Electro-hydraulic power steering system (EHPS) maintains the advantages of Hydraulic power steering system (HPS) and Electric power steering system (EPS).It is even more superior than this two. In the foreseeable future, this system will have a certain development space. Assistant characters analysis was carried out in this paper. Control strategy based on steering states and feedback control strategy were designed too. Besides, aiming at the emergency steering conditions, steering angular velocity additional controlling strategy was brought out. Under emergency steering conditions, steering angular velocity additional controlling strategy will be applied. Additional steering moment will be calculated to ensure the assistant follow steering rapidly.
2015-09-29
Technical Paper
2015-01-2720
Sundarram Arunachalam, Ramprabhu Kannan, Jayaramareddy Sekar
Abstract Steering gear box function is one of the important requirements in heavy vehicles in order to reduce driver fatigue. Improper functioning of steering gear box not only increases the driver fatigue, also concerns the safety of the vehicle. In this present investigation, the engine oil mixing up with steering oil has been identified and steering gear box failure has been observed in the customer vehicle. The root cause of failure has been analyzed. Based on the investigations, in particular design of steering pump has been failed at customer end. The same design of steering pump were segregated and analyzed. Initial pressure mapping study has been conducted. The pressure mapping results revealed that the cavity pressure obstructs the flow of suction pressure. It indicates that obstacle at suction port due to the existence of internal leakage that causes back pressure in the internal cavity of steering pump which sucks engine oil.
2015-09-29
Technical Paper
2015-01-2721
Balaji Lomada, R. Jayaganthan, V. Vijaykumar
Abstract 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 and gross vehicle weight (GVW) of the bus for the same passenger capacity. Usually, steering system of longer front overhang (FOH) vehicles have multiple linkages such as bevel box arrangement or intermediate pivot arm arrangement instead of single direct draglink because of packaging and design constraints. In this work, an attempt has been made to design the steering system for one of the longer FOH bus with single direct draglink arrangement. Here, single draglink was packaged and designed with commercially available higher strength tube material. Design optimisation of steering geometry was carried such that the steering performance was atleast on par with existing performance.
2015-09-29
Technical Paper
2015-01-2734
Anand Deshpande, Himanshu Gambhir, Kshitiz Raj, Satish Kumar
Abstract Low steering effort is the basic requisite to proffer driver with drive comfort and easy maneuverability on turns. Various components in steering and suspension system play a vital role in determining the steering effort of vehicle. The discussion has been emphasized on static steering effort i.e. when vehicle is stationary and wheels are turned from lock to lock position. There are various factors which affect the steering effort of a vehicle. Following are the high priority factors: 1 Steering Geometry.2 Tyre static friction torque.3 Friction among the steering linkages. In this paper, the crucial factors which lead to difference in steering effort of RH and LH turn have been discussed in detail.
2015-09-29
Technical Paper
2015-01-2733
Samraj Benedicts, Vivek Seshan
Track tensioning assembly is used in tracked vehicles to maintain the tautness of the track. The track tensioning system consists of the rear idler wheel which applies pressure on the track and a mechanism to increase or decrease the tension. This paper is a study of reaction forces and its effects on the chassis due to rear idler position. Rubber track layouts have been focus for most of the research work, here we study the effect of rear idler position on chassis structure through simulated analysis. An agriculture paddy combine harvester with rubber track is considered for the purpose of this work. Firstly the complete chassis structure 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.
2015-09-29
Technical Paper
2015-01-2732
Andrei Keller, Sergei Aliukov
Abstract The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity, and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-to-weight ratio of the vehicle and its weight, the growth rate of the velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical. In this investigation we evaluate the effectiveness of the main methods of power distribution among drive wheels of the multi-purpose wheeled vehicles.
2015-09-29
Technical Paper
2015-01-2729
Guoying Chen, Lei He, Hongyu Zheng, Yaohua Guo
Abstract For the vehicles equipped with Electric Power Steering (EPS) system, the friction and damping effect brought by assisted motor and worm gear mechanism influence the return ability and handing stability. In order to eliminate the impacts, it is necessary to add return-to-center control in EPS control strategy. This paper proposes a practical active return-to-center control strategy with steering wheel angle signals based on return state identification. In the strategy, the return state of the steering system is identified quickly according to the two signals steering wheel angle velocity and steering wheel torque. Only under return state, a double closed-loop PID control strategy is carried out to calculate a compensation current to improve the return ability. For validating the proposed strategy, a fine EPS model including BLDC assisted motor is built based on carsim and simulink co-simulation platform.
2015-09-29
Technical Paper
2015-01-2749
Yang Chen, Mehdi Ahmadian, Andrew Peterson
Abstract This study provides a simulation evaluation of the effect of maintaining balanced airflow, both statically and dynamically, in heavy truck air suspensions on vehicle roll stability. The model includes a multi-domain evaluation of the truck multi-body dynamics combined with detailed pneumatic dynamics of drive-axle air suspensions. The analysis is performed based on a detailed model of the suspension's pneumatics, from the main reservoir to the airsprings, of a new generation of air suspensions with two leveling valves and air hoses and fittings that are intended to increase the dynamic bandwidth of the pneumatic suspensions. The suspension pneumatics are designed such that they are able to better respond to body motion in real time. Specifically, this study aims to better understand the airflow dynamics and how they couple with the vehicle dynamics.
2015-09-29
Technical Paper
2015-01-2748
Salem A. Haggag
Abstract The vehicle dynamics and controls play a significant role in vehicle handling performance characteristics. The control of vehicle braking system and wheel slip is a challenging problem due to the nonlinear dynamics of the braking process and the wheel-road interaction. A simple and at the same time realistic vehicle longitudinal braking model is essential for such a challenging problem. In this paper, a new longitudinal rolling/braking quarter-vehicle model is presented. The proposed model takes both the rolling resistance force and the braking force into consideration and investigates their impact on the vehicle longitudinal dynamics. An anti-lock sliding-mode controller is designed to provide wheel slip control during vehicle motion. This type of controller is chosen due to its expected robustness against varying road friction coefficient.
2015-09-29
Technical Paper
2015-01-2746
Bin Li, Subhash Rakheja
Abstract Vehicle jackknifing is generally associated with the loss of yaw stability, and is one of the most common cause of serious traffic accidents involving tractor-semitrailer combinations. In this paper, an active braking control strategy is proposed for jackknifing prevention of a tractor-semitrailer combination on a low friction road. The proposed control strategy is realized via upper-level and lower-level control structures considering braking of both the units. In the upper-level control, the required corrective yaw moments for tractor and semitrailer are generated using a PID controller aiming to reduce errors between the actual yaw rates of tractor-semitrailer and the target yaw rates deduced from a reference model. The corrective yaw moments are achieved through brake torque distribution among the tractor and semitrailer axle wheels in the lower-level control.
2015-09-29
Technical Paper
2015-01-2742
Linlin Wang, Hongyu Zheng, Changfu Zong, Yuchao Chen
Abstract Aiming at estimating the vehicle mass and the position of center of gravity, an on-line two-stage estimator, based on the recursive least square method, is proposed for buses in this paper. Accurate information of the center of gravity position is crucial to vehicle control, especially for buses whose center of gravity position can be varied substantially because of the payload onboard. Considering that the buses start and stop frequently, the first stage of the estimator determines the bus total mass during acceleration, and the second stage utilizes the recursive least-square methods to estimate the position of the center of gravity during braking. The proposed estimator can be validated by the co-simulation with MATLAB/Simulink and TruckSim software, simulation results exhibit good convergence and stability, so the center of gravity position can be estimated through the proposed method in a certain accuracy range.
2015-09-29
Technical Paper
2015-01-2740
Yuming Yin, Subhash Rakheja, Jue Yang, P. E. Boileau
Abstract The articulated frame steering (AFS) systems are widely implemented in construction, forestry and mining vehicles to achieve enhanced maneuverability and traction performances. The kinematic and dynamic performances of articulated steered vehicles are strongly influenced by properties of the frame steering system. In this paper, a flow volume regulated frame steering system is described and analytically modelled. The analytical model of the steering system is formulated in conjunction with yaw-plane model of a 35 tonnes mining vehicle to investigate steady as well as transient responses of the steering system and the vehicle. A field test program was undertaken to measure responses of the steering system and the vehicle under nearly constant speed turning as well as path-change maneuvers.
2015-09-29
Technical Paper
2015-01-2741
Yunbo Hou, Mehdi Ahmadian
Abstract This paper presents the results of a study on the effect of truck configurations on the roll stability of commercial trucks in roundabouts that are commonly used in urban settings with increasing frequency. The special geometric layout of roundabouts can increase the risk of rollover in high-CG vehicles, even at low speeds. Relatively few in-depth studies have been conducted on rollover stability of commercial trucks in roundabouts. This study uses a commercially available software, TruckSim®, to perform simulations on four truck configurations, including a single-unit truck, a WB-67 semi-truck, the combination of a tractor with double 28-ft trailers, and the combination of a tractor with double 40-ft trailers. A single-lane and multilane roundabout are modeled, both with a truck apron. Three travel movements through the roundabouts are considered, including right turn, through-movement, and left turn.
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
2015-01-2762
Chunshan Li, Pan Song, Guoying Chen, Changfu Zong, Wenchao Liu
Abstract This paper presents an integrated chassis controller with multiple hierarchical layers for 4WID/4WIS electric vehicle. The proposed systematic design consists of the following four parts: 1) a reference model is in the driver control layer, which maps the relationship between the driver's inputs and the desired vehicle motion. 2) a sliding mode controller is in the vehicle motion control layer, whose objective is to keep the vehicle following the desired motion commands generated in the driver control layer. 3) By considering the tire adhesive limits, a tire force allocator is in the control allocation layer, which optimally distributes the generalized forces/moments to the four wheels so as to minimize the tire workloads during normal driving. 4) an actuator controller is in the executive layer, which calculates the driving torques of the in-wheel motors and steering angles of the four wheels in order to finally achieve the distributed tire forces.
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.
2015-09-29
Technical Paper
2015-01-2750
Tan Huang, Guoying Chen, Changfu Zong, Tong Zhou
Abstract Electronically controlled air suspension (ECAS) systems have been widely used in commercial vehicles to improve the ride comfort and handling stability of vehicles, as it can adjust vehicle height according to the driving conditions and the driver's intent. In this paper, the vehicle height adjustment process of ECAS system is studied. A mathematical model of vehicle height adjustment is derived by combining vehicle dynamics theory and thermodynamics theory of variable mass system. Reasons lead to the problems of “over-charging”, “over-discharging” and oscillation during the process of height adjustment are analyzed. In order to solve these problems, a single neuron proportional-integral-derivative (PID) controller is proposed to realize the accurate control of vehicle height. By simulation and semi-physical rig test, the effectiveness and performance of the proposed control algorithm are verified.
2015-09-29
Technical Paper
2015-01-2753
Xiujian Yang, Ruocheng Zhu, Jin Gao
Abstract Tractor semi-trailer as a widely-used heavy duty freight vehicle has caused many fatal accidents every year and one of the main factors of which may relate to its relatively poor lateral dynamics performance compared to the passenger cars [1, 2, 3]. In this paper, attention is concentrated on the parametric design for a tractor semi-trailer by optimizing the configuration parameters aiming to comprehensively improve the lateral dynamics performance. According to the previous public reports, the performance measures such as Load Transfer Ratio (LTR), Static Rollover Threshold (SRT), Rearward Amplification Ratio (RAR) and Ratio of Yaw Rate (RYR) are very effective measures and often be used to evaluate the handling and stability performances for tractor-trailer vehicles. However, each of those measures only pays attention to a certain aspect of vehicle lateral dynamics which is closely related to vehicle configuration parameters.
2015-09-29
Technical Paper
2015-01-2756
Basaran Ozmen, Mehmet Bakir, Murat Siktas, Serter Atamer, Roman Teutsch
Abstract Securing the desired strength and durability characteristics of suspension components is one of the most important topics in the development of commercial vehicles because these components undergo multiaxial variable amplitude loading. Leaf springs are essential for the suspension systems of trucks and they are considered as security relevant components in the product development phase. In order to guide the engineers in the design and testing department, a simulation method is developed as explained by Bakir et al. in a recently published SAE paper [1]. The main aim of the present study is to illustrate the validation of this simulation method for the durability of leaf springs based on the results from testing and measurements. In order to verify this CAE Method, the calculated stresses on the leaf springs are compared with the results of strain gage measurements and the fatigue failures of leaf springs are correlated with the calculated damage values.
2015-09-29
Technical Paper
2015-01-2801
Yuandong Liu, Gangfeng Tan, Xuexun Guo, Li Zhou, Wenbin Liu, Zhiqiang Hu, Kangping Ji, Binyu Mei
Abstract The hydraulic retarder, 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 by the rotor of hydraulic retarder's stirring the air, causes pumping loss. This research designs a new type of hydraulic retarder, whose 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 on the base of 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 analyzed under non-braking working condition.
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