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2016-04-05
Technical Paper
2016-01-0440
Li Jie, Wang Wenzhu, Gao Xiong, Zhang Zhenwei
The heavy truck often moves in a poor, long-distance and high-speed freight state environment, so drivers are easy to fatigue and goods are easily damaged. At the same time, compared to the passenger car, the ride comfort of heavy trucks has a lot of room for improvement. Therefore, the research on the ride comfort of heavy trucks becomes crucial.Based the elastic theory of Euler-Bernoulli beam with both free ends, a 6 DOF half rigid-elastic vibration model of the vertical dynamic response is developed, which is more suitable to the actual movement of heavy trucks. The DOFs include: vertical displacements of the body and each of two axles; the pitch displacement of the body; the first and second order bending displacements of the body. The root mean square values of body acceleration, dynamic deflections and relative dynamic loads act as evaluation index.
2016-04-05
Technical Paper
2016-01-1059
Huyao Wu, Fei Huo
In this paper, as the common principle of some engineering applications, a compound pendulum consists of two bodies and relevant force elements, of springs and dampers is considered, whose governing equations are created as Newton’s Second Law, which is the ordinary differential equations (ODES) with the periodic time-variant coefficients and non-autonomous system. Further combine the engineering cases based on the G. Floquet Theory, the numeric analysis whose different types of solutions are examined, the stability problem for the time variant ODES on the zero-solutions is discussed. Relevant stability diagram and various responses are provided for different kinds of excitations, kinetic and dynamic parameters. Finally discuss the application of principles and phenomenon in automotive field.
2016-04-05
Technical Paper
2016-01-0132
Haizhen Liu, Weiwen Deng, Rui He, Jian Wu, Bing Zhu
Brake-by-wire (BBW) system has drawn a great attention in recent years as driven by rapidly increasing demands on both active brake controls for intelligent vehicles and regenerative braking controls for electric vehicles. However, unlike conversional brake systems, the reliability of the brake-by-wire systems remains to be challenging due to its lack of physical connection in case system failure. A four-wheeled vehicle is typically an over-actuated system, as it has more actuators than the number of degrees to be controlled in vehicle yaw plane (longitudinal, lateral and yaw motion). Control allocation method has often been utilized as a means for fault-tolerant control. A great deal of researches has been done on fault-tolerant control based on control allocation method. There are basically two methods in fault-tolerant control: an optimization-based approach and a rule-based approach.
2016-04-05
Technical Paper
2016-01-0134
Sagar Behere, Xinhai Zhang, Viacheslav Izosimov, Martin Törngren
Heavy commercial vehicles constitute the dominant form of inland freight transport. There is a strong interest in making such vehicles autonomous (self-driving), in order to improve safety and the economics of fleet operation. Autonomy concerns affect a number of key systems within the vehicle. One such key system is brakes, which need to remain continuously available throughout vehicle operation. This paper presents a fail-operational functional brake architecture for autonomous heavy commercial vehicles. The architecture is based on a reconfiguration of the existing brake systems in a typical vehicle, in order to attain dynamic, diversified redundancy along with desired brake performance. Specifically, the parking brake is modified to act as a secondary brake with capabilities for monitoring and intervention of the primary brake system.
2016-04-05
Technical Paper
2016-01-1545
Huan Liu, Guoying Chen, Changfu Zong
Comparing with traditional steering system, motor and reducing mechanism are added to Electric Power Steering System(EPS), this part of the existence of additional hardware increase the friction torque of steering system, which affect vehicle’s steering portability, return-to-center performance and central road feel at low speed and high-speed. To overcome the friction resistance moment, and formulate the corresponding control strategy to exert friction compensation control system, appropriate friction model must be selected to describe the friction properties of EPS system. The current EPS friction model can’t describe the friction torque’s smoothness and hysteresis characteristics, so a new electric power steering system dynamic friction model based on normalized Bouc-Wen model is given, as well as its structure form and model features. In addition, experimental method has been used to identify corresponding parameters.
2016-04-05
Technical Paper
2016-01-0051
Hongyu Zheng, Mingxin Zhao
Electric power steering, active front wheel steering and steer by wire systems can improve the steering portability at low speed and ameliorate the steering feeling at high speed, so as to enhance the handling stability of the vehicle. It can even perform an active steering intervention in dangerous working conditions to increase the active safety of automobile. However, the development of the electric steering system , which needs to test and modify repeatedly, involves the machinery, the controller hardware , control algorithm and many other aspects of designs. Now the development of the electric steering system is mainly based on the way that combines the test of the electric steering hardware-in-loop(HIL) test bench with real vehicle road test. But the real vehicle test with higher cost, long cycle and vulnerable to space weather have the potential safety problems at the beginning of the system development.
2016-04-05
Technical Paper
2016-01-1550
Ming Peng, Xuexun Guo, Junyi Zou, Chengcai Zhang
This paper presents a novel concept of the application of the hydraulic electromagnetic energy-regenerative shock absorber (HESA) into the commercial vehicle suspension system and the vehicle road performances are simulated by the evaluating indexes (e.g. the root-mean-square values of vertical acceleration of sprung mass, dynamic tire-ground contact force, suspension deflection and harvested power). Firstly, the configuration and working principle of the HESA are introduced. Then, the damping characteristics of the HESA and the seven-degrees-of-freedom vehicle dynamics were modeled respectively before derive the dynamic characteristics of a vehicle equipped with the HESA. The control current is fixed at 7A to match the similar damping effect of traditional linear damper on the basis of the energy conversion method of nonlinear shock absorber.
2016-04-05
Technical Paper
2016-01-1453
I-Hsuan Lee, Bi-Cheng Luan
Autonomous emergency braking (AEB) systems is one of the functions of the Advanced Driver Assists System to avoid or mitigate vehicle frontal collisions. Most of the previous studies focus on two-car scenario where the host vehicle monitors the distances to the vehicles in front, and automatically applies emergency brake when a collision is imminent. The purpose of this paper is to develop an Advanced-AEB control system that mitigates collisions in a multi-car scenario by computing the Time-to-Collision (TTC) to the vehicles in front as well as those to the vehicles behind using the concept of impedance control. A simple gain-scheduling PI controller was designed for the host vehicle to track the reference inputs generated by the impedance control. The preliminary simulation results demonstrate that the proposed AEB is effective in mitigating the collisions in a 3-car following scenario.
2016-04-05
Technical Paper
2016-01-1301
Shishuo Sun, David W. Herrin, John Baker
One of the more useful metrics to characterize an isolator is insertion loss. Insertion loss is defined as the difference in transmitted vibration in decibels between the unisolated and isolated cases. Insertion loss is superior to transmissibility in that effects of source and receiver compliance are also included. In this work, the transfer matrix of a spring isolator is determined using finite element simulation and the insertion loss is then determined using assumed values for the compliance on the source and receiver sides. Following this, the effect of different spring parameters such as the number of turns, wire diameter, spring diameter, and damping are investigated.
2016-04-05
Technical Paper
2016-01-0454
Hongyu Zheng, Shenao Ma
As a new braking system, EHB can significantly improve the braking performance and vehicle handling and stability. A number of factors impacts the EHB system characteristics, wheel cylinder pressure are regulated by in-solenoid and out-solenoid valve, the dynamic response of the control strategy will impact the accuracy of wheel cylinder pressure greatly. In this paper the structure of high-speed on-off valve and the valve core principle are discussed, the paper also analysis the response of the valve core under different modulation frequency and duty cycle and the change of wheel cylinder pressure. Setting a proper modulation frequency to make sure that electromagnetic valve can be worked in a greater linear range.
2016-04-05
Technical Paper
2016-01-0029
Chuanliangzi Liu, Bo Chen, Ming Cheng, Anthony Champagne, Keyur Patel
The Electronic Control Unit (ECU) of the Electric Power Steering (EPS) system is a core device to control the electric motor to provide assist while steering. The Hardware-in-the-loop (HiL) simulation will help identify early safety issues in the development phase of a project. The intent of this paper is to focus on vehicle dynamics simulation of the EPS using the HiL system. The EPS plant model, dSPACE Vehicle Dynamics model and dSPACE Motor Model interact with a dSPACE hardware platform and a real ECU. This paper includes the design of the EPS HiL system, the simulation of sensors & actuators, the function of Automotive Simulation Model (ASM) Vehicle Dynamics model, and the integration method of the ASM Vehicle Dynamics model with the EPS model. The offline simulation of the integrated model is performed and the simulation results of different driving maneuvers are presented.
2016-04-05
Technical Paper
2016-01-0146
Yonghwan Jeong, Seonwook Kim, Kyongsu Yi, Sangyong Lee, ByeongRim Jo
This paper represents the parking lot occupancy detection algorithm and the parking control algorithm for autonomous valet parking system. With the assumption that the global parking map exists, the occupancy of the parking space is measured using a two-dimensional Light Detection and Ranging (LIDAR) sensor mounted at each side of front bumper. The Euclidean minimum spanning tree (EMST) method is used to cluster the point information from LIDAR. The global parking map includes all parking lots and access road. The proposed parking control algorithm consists of a desired path generation, a path tracking controller, and a parking process controller. At first, route points of the desired path are determined under the consideration of the minimum turning radius and minimum safety margin with near parking spaces. The desired path is generated by connecting straight lines and arcs between pre-determined route points.
2016-04-05
Journal Article
2016-01-0426
Francisco C. Cione, Armando Souza, Luiz Martinez, Jesualdo Rossi, Evandro Giuseppe Betini, Fabio Rola, Marco A. Colosio
Studying the formation and distribution of residual stress fields will improve the operational criteria of wheel safety, among other gains. Many engineering specifications, manufacturing procedures, inspection and quality control have begun to require that the residual stress of a particular component be evaluated. It is known that these residual stress fields could be added to the effects of system load (tare weight plus occupation of vehicle traction, braking and torque combined). The results obtained used X-ray diffraction, drilling method with rosette type strain gages, are convergent with similarity to those obtained using FEA simulation over critical region for global and superficial in principal stresses mode. The mathematical tools for modeling and simulations using finite elements had evolved following the increasing computing power and hardware cost reduction.
2016-04-05
Journal Article
2016-01-0433
Tao Sun, Eungkil Lee, Yuping He
This paper presents nonlinear bifurcation stability analysis of articulated vehicles with active trailer differential braking (ATDB) systems. ATDB systems have been proposed to improve stability of articulated vehicle systems to prevent unstable motion modes, e.g., jack-knifing, trailer sway and rollover. Generally, behaviors of a nonlinear dynamic system may change with varying parameters. A stable equilibrium can become unstable and a periodic oscillation may occur or a new equilibrium may appear making the previous equilibrium unstable. The value of a parameter at which these changes occur is known as “bifurcation value” and the parameter is known as the “bifurcation parameter”. Conventionally, nonlinear bifurcation analysis approach is applied to examine the nonlinear dynamic characteristics of single unit vehicles, e.g., cars, trucks, etc.
2016-04-05
Journal Article
2016-01-0438
Ye Yuan, Junzhi Zhang, Chen Lv, Yutong Li
Due to its importance in energy saving, regenerative braking has become a key technology of various types of electrified vehicles. Regenerative braking system (RBS), converting vehicle’s kinetic energy into electricity during decelerations, improves the energy efficiency of electrified vehicles significantly. In this paper, a new type of RBS is proposed for electric vehicles. To realize the cooperative control of regenerative braking and hydraulic braking, 4 pressure-difference-limit valves, 2 relief valves, and 2 brake pedal simulators, are added to the layout of a conventional 4-channel hydraulic modulator. The cooperation of relief valves and hydraulic pumps provides a stabilized high-pressure source. Pressure-difference-limit valves ensure that the pressure in each wheel cylinder can be modulated separately at a high precision. Besides, the functions of anti-lock braking system (ABS) and electronic stability program (ESP) are also integrated in this RBS.
2016-04-05
Journal Article
2016-01-1666
Ryo Yamaguchi, Hiromichi Nozaki
About three controls of the inside-outside wheel braking force and driving force control, the camber angle control, and the derivative steering assistance control in this research, the difference of the degree in the effect of the cornering performance and the controllability by the difference of the body slip angle area was compared by the closed loop examination in a wide-ranging running area from the grip area to the drift area with a driving simulator. As a result, it has been understood to do with stability even by the inside-outside wheel braking force and driving force control in the area just before the critical cornering. On the other hand, because the grip cornering force rose by controlling the camber angle, it was confirmed that the side-slip limit improved in the vicinity of the critical cornering.
2016-04-05
Technical Paper
2016-01-1543
Donald F. Tandy, Scott Hanba, Robert Pascarella
One important part of the vehicle design process is suspension design and tuning. This is typically performed by experienced expert evaluators with assistance from vehicle dynamics computer simulation tools. One part of this process is the development and tuning of the damping characteristics of the shock absorbers. Recently, in a series of three ASME papers published by employees of an Arkansas litigation firm, a new and supposedly “novel” approach to shock absorber damping tuning was presented. The papers propose a theory which supposedly provided an automotive engineer with a method by which rear suspension shock absorber damping could be easily selected to provide appropriate damping to the vehicle. The work is based on experiments where rubber blocks are glued to tires so as to force the rear suspension to hop and tramp.
2016-04-05
Technical Paper
2016-01-1544
Dexin Wang, Frank Esser
Evaluation of electric steering (EPAS) system performance using vehicle specific load conditions is important for steering system design validation and vehicle steering performance tuning. Using real-time vehicle dynamics math models is one of approaches for steering HIL testing. However achieving a good correlation of simplified math models with real vehicle dynamics is a challenge. Using rack force models from measured steering tie rod forces is an effective data-driven modeling method for testing EPAS systems under vehicle specific load conditions.Rack force models are identified from measurements for those test maneuvers for evaluating vehicle steering performance.
2016-04-05
Journal Article
2016-01-1376
Feng Qi, Sujan Dhar, Varun Haresh Nichani, Chiranth Srinivasan, De Ming Wang, Liang Yang, Zhonghui Bing, Jinming Jim Yang
External gear pumps are positive displacement devices which perform with excellent efficiencies over a wide load and speed range. This wide range of performance is primarily due to micron-level leakage gaps in such machines which prevent large leakages at increasing loads. The present paper details a novel approach implemented in the commercial CFD tool PumpLinx that can capture the details of the micron level gaps, and model such machines accurately. The steps in creation of the model from original CAD geometry are described. In particular, the CFD mesh is created using a specialized template structured meshing method within PumpLinx especially created for external gear pumps and motors. This makes process of mesh creation and flow solution through complicated geometries of a gear pump efficient and streamlined.
2016-04-05
Journal Article
2016-01-1375
Masahiro Ueda, Satoshi Ito, Daichi Suzuki
Good ride comfort performance, which is represented by noise, vibration, harshness, has high solicitation power for customers. These phenomena are a result of vibration caused at the engine/powertrain or from road surfaces, transmitted to cabin. Therefore, for reduction of these vibrations, a large number of rubber parts are used at the attachment point of cabin, such as engine mounting and suspension bushing. In the vehicle development, demands to examine the vehicle performance including rubber parts using CAE, before prototype evaluation, is increasing. For that reason, a rubber material model which can represent dynamic characteristics (amplitude dependence, frequency dependence, etc.) of the rubber parts with high precision is necessary, but it is difficult to perform amplitude dependence and frequency dependence at the same time using the rubber material model implemented by commercial structure analysis solver.
2016-04-05
Journal Article
2016-01-1569
Kiho Yum
In this research, the influence of tire force and moment (F&M) characteristics on vehicle on-center steering performance was analyzed and then how to improve vehicle on-center performance was studied through controlling tire structure design parameter and tire tread grip characteristics. First, the relationship between vehicle on-center steering performance and tire F&M characteristics was identified by comparing vehicle steering measurement and tire F&M measurement. It was found that on-center steering performance is improved as the aligning torque at slip angle 1° increases. Secondly the influence of tire structure design parameter on tire aligning torque was studied by tire F&M finite element analysis. It was also found aligning torque increases as tire tread and sidewall stiffness decreases. However it shows trade-off characteristics with tire cornering force stiffness so it is necessary to optimize cornering force stiffness and aligning torque stiffness.
2016-04-05
Journal Article
2016-01-1568
L. Daniel Metz
Roadway tractive capabilities are an important factor in acci-dent reconstruction. In the absence of full-scale experiments, tire/road coefficient of friction values are sometimes quoted from reference textbooks. For the various types of road con-struction, the values are given only in the form of a wide range. One common roadway type is oil-and-chip construction. We examine stopping distances for newly-rocked oil-and-chip roads vs. similarly constructed roads that have been traffic- polished. The examination was conducted through full-scale braking experiments with instrumented vehicles. Results show that the differences between newly-rocked oil-and-chip roads when compared to roads that are traffic-polished are on the same order as vehicle, tire and ABS algorithm differences, and that full-scale testing is required for accurate μ-values.
2016-04-05
Journal Article
2016-01-1553
Akihito Yamamoto, Wataru Tanaka, Takafumi Makino, Shunya Tanaka, Ken Tahara
In recent years, semi active suspension systems which are energy saving and low cost have already been adopted in various vehicles to improve ride comfort and vehicle controllability. At the same time, various reports have been published that examine the control laws for ride comfort using these systems. Controlling ride comfort with semi active suspension systems, it is necessary to estimate the suspension stroke velocity. There are researches of the observer using suspension stroke sensor and vertical acceleration sensor on sprung mass. However, there are researches of the observer using vertical acceleration sensor on un-sprung mass to develop the simple and low cost semi active suspension systems too. The study described in this paper aim to further enhance the estimation precision of the suspension stroke velocity using the vertical acceleration sensor on the un-sprung mass.
2016-04-05
Journal Article
2016-01-1572
Jugal Popat, Aneesh Nabar, Meighan Read, Chen Fu, Chunhui Zhang, Galab Kausik, Harsh Patel, Peter Thomas Tkacik
Public information is seriously lacking on studies of something so critical to safety as passenger vehicle tire pressures. This paper is the result of measurements on hundreds of vehicles and the most surprising results are presented regarding the influence of tire pressure monitoring systems (TPMS) and the new trend toward spare tire locations and use. Gathering this data is notoriously difficult due to the psychological hurdles involved in gaining access to a trunk that is typically embarrassingly cluttered and the time required to measure a tire buried under floor boards. One key observation is that spare tires are often left unchecked or overlooked in between regular vehicle maintenance resulting in safety issues for drivers. The vehicles sampled ranged from full-sized pick-up trucks to compact cars. The study included vehicle model years from 1965 to 2015 (50 year range).
2016-04-05
Journal Article
2016-01-1571
Harsh Patel, Michael Casino, David Noakes, Nicholas Kauffman, Daniel Rohwedder, Jugal Popat, Aneesh Nabar, Peter Thomas Tkacik
This paper is part of a bigger research effort that includes hundreds of passenger vehicle wheel alignment measurements and a design of experiments that works to capture the various factors. Of the many things that influence the accuracy and repeatability of vehicle suspension alignment measurement and adjustment, the design of the suspension can be the most significant. This includes but is not limited to adjustment configuration, suspension design, static alignment settings, and bushing stiffness. Measurements were using a Hunter Pro-Align with DSP700 wheel sensors in the Motorsports Research Building at the University of North Carolina at Charlotte. All vehicles were reviewed and any with suspension damage were rejected prior to measurement. The collection of vehicles measured included the category of small front wheel drive, full size rear drive, seven passenger SUV, sports car, and race car. A small sporty sedan was also tested and modified to assess bushing stiffness influence.
2016-04-05
Journal Article
2016-01-0457
Yutong Li, Junzhi Zhang, Chen Lv, Ye Yuan
This paper presents a coordinated control algorithm for comprehensive optimization of vehicle dynamics performance and energy consumption for a full drive-by-wire electric vehicle, which is driven by a four in-wheel motor actuated (FIWMA) system and steered by a steer-by-wire (SBW) system. In order to coordinate the FIWMA and SBW systems, the mechanisms influencing the vehicle dynamics control performance and the energy consumption of the two systems are first derived based on quantitative analyses of a typical vehicle motion control process. Second, the control algorithms for each subsystem are developed. For the SBW system, a triple-step control technique is implemented to decouple the yaw rate and sideslip angle controls, which makes control parameter tuning easier.
2016-04-05
Journal Article
2016-01-0461
Wenfei Li, Haiping Du, Weihua Li
this paper proposes a new braking torque distribution strategy for electric vehicles equipped with a hybrid hydraulic braking and regenerative braking system. The braking torque distribution strategy is proposed based on the required braking torque and the regenerative braking system’s status. To get the required braking torque, a new strategy is designed based on the road conditions and driver's braking intentions. Through the estimated road surface, a robust wheel slip controller is designed to calculate the overall maximum braking torque required for the anti-lock braking system (ABS) under this road condition. Driver's braking intentions are classified as the emergency brake and the normal brake. In the case of emergency braking, the required braking torque is to be equal to the maximum braking torque. In the case of normal braking, the normal brake torque is proportional to pedal stroke.
2016-04-05
Journal Article
2016-01-0466
Daan Roethof, Tarik Sezer, Mustafa Ali Arat, Barys Shyrokau
The wheel-camber geometry holds considerable potential to improve vehicle safety and performance, which has led to the development of numerous unique camber mechanisms with active or self-regulating features over the last decade. An extended overview of these prototypes, as included in this report, reveals that most of the investigations employ so-called open-loop manoeuvres to evaluate the vehicle response excluding driver response. However, driver’s perception and his/her reaction is a crucial if not the most critical factor during vehicle operation. Therefore, the research goal of the presented study is to assess the influence of active camber control on steering feel and driving performance using a driving simulator. In the proposed investigation, the vehicle body dynamics are based on dSPACE ASM software and have been extended by comprehensive models of the steering and active camber regulation systems.
2016-04-05
Journal Article
2016-01-0467
Haizhen Liu, Weiwen Deng, Rui He, Jian Wu, Bing Zhu
Modern brake control system has been widely used not only for handling and stability, but also more and more towards handling driver assistance and active safety features, such as ACC, and RBS for EVs. As a result of the increasing number and complexity of brake control features, the functional overlap and interaction of each subsystem become inevitable with multiple objectives ranging from enhanced safety and stability, comfort and convenience, to energy saving. Under the conventional control architecture, since each of these features or subsystems may be developed by an individual supplier independently from each other, the integration and coordination among them become more and more complex. The ability to interchange one supplier's subsystem with another becomes problematic, which often causes inevitable duplications. This paper presents a novel function-based brake control architecture, which is designed based on a top-down approach with functional abstraction and modularity.
2016-04-05
Journal Article
2016-01-0477
Pu Gao, Yongchang Du, Yujian Wang, Yingping Lv
The dynamic properties of disc rotor play important role in the NVH performance of a disc brake system. Disc rotor in general is a centro-symmetric structure. It has many repeated-root modes within the interested frequency range and they may have significant influence on squeal occurrence. A pair of repeated-root modes is in nature one vibration mode. However, in current complex eigenvalue analysis model and relevant analysis methods, repeated-root modes are processed separately. This may lead to contradictory result. This paper presents methods to deal with repeated-root modes in substructure modal composition (SMC) analysis to avoid the contradiction. Through curve-fitting technique the modal shape coefficients of repeated-root modes are expressed in an identical formula. This formula is used in SMC analysis to obtain an integrated SMC value to represent the total influence of two repeated-root modes.
Viewing 31 to 60 of 211

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