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Viewing 61 to 90 of 10886
2017-03-28
Technical Paper
2017-01-1571
Kevin McLaughlin, Jonah Shapiro, HyungJu Kwon
An approach to electric steering control is provided that uses vehicle dynamics and quantitative steering objectives to tune the steering system. The steering objective chosen is a torque vs. lateral acceleration target for the driver. The commanded torque vs. lateral acceleration gain is termed the “steering gain”. The steering gain is achieved independently of the ability of the controller to reject unwanted effects such as friction. Two parameters are computed using vehicle dynamics that substantially determine driver feel: the vehicle’s “manual gain” (total steering torque divided by lateral acceleration) and the vehicle’s lateral acceleration gain (lateral acceleration divided by steering angle). Lateral acceleration gain is a well known quantity in the literature but the concept of manual gain is new for steering control.
2017-03-28
Technical Paper
2017-01-1326
Santhoji Katare, Ravichandran S, Gokul Ram, Giri Nammalwar
Model based computer aided processes offer an economical and accelerated alternative to traditional build-and-test Edisonian approaches to engineering design. Typically a CAE based design problem is formulated in two parts, viz. (1) the inverse problem which involves identification of the appropriate product geometry given desired property requirements, and (2) the forward problem which is the computation or prediction of product performance measures from the product geometry. Solution to the forward problem requires development of an accurate model that is correlated to physical data. This validated model could then be used for virtual verification and design of engineering systems efficiently. This paper demonstrates the rigorous process of model development, model calibration, model validation, and use of the calibrated model in the design process with practical examples from automotive suspension, brakes and powertrain systems.
2017-03-28
Technical Paper
2017-01-0416
Vishal Barde, Baskar Anthonysamy, Ganeshan Reddy, Senthil S, Visweswara lenka, Gurdeep Singh Pahwa
Abstract New trend in steering system such as EPS is coming up, but still hydraulic power steering system is more prevalent in today’s vehicles. Power steering pump is a vital component of hydraulic power steering system. Failure of steering pump can lead to loss of power assistance. Prediction of hub load on pump shaft is an important design input for pump manufacturer. Higher hub loads than the actual designed load of pump bearing may lead to seizure of pump. Pump manufacturer has safe limits for hub load. Simulations can assist for optimization of belt layout and placement of accessories to reduce the hub load. Lower hub load can have direct effect on improvement of pump durability. This paper deals with dynamic simulation of belt drive system in MSC.ADAMS as well as vehicle level measurement of hub load on power steering pump.
2017-03-28
Journal Article
2017-01-1578
Tianyang Liu, Zhuoping Yu, Lu Xiong, Wei HAN
Two control strategies, safety preferred control and master cylinder oscillation control, were designed for anti-lock braking on a novel integrated-electro-hydraulic braking system (I-EHB) which has only four solenoid valves in its innovative hydraulic control unit (HCU) instead of eight in a traditional one. The main idea of safety preferred control is to reduce the hydraulic pressure provided by the motor in the master cylinder whenever a wheel tends to be locking even if some of the other wheels may need more braking torque while regarding master cylinder oscillation control, a sinusoidal signal is given to the motor making the hydraulic pressure in the master cylinder oscillate in a certain frequency and amplitude. Hardware-in-the-loop simulations were conducted to verify the effectiveness of the two control strategies mentioned above and to evaluate them.
2017-03-28
Technical Paper
2017-01-0455
Harshad Hatekar, Baskar Anthonysamy, V. Saishanker, Lakshmi Pavuluri, Gurdeep Singh Pahwa
Abstract Structural elastomer components like bushes, engine mounts are required to meet stringent and contrasting requirements of being soft for better NVH and also be durable at different loading conditions and different road conditions. Silent block bushes are such components where the loading in radial direction of bushes are high to ensure the durability of bushes at high loads, but has to be soft on torsion to ensure good NVH. These requirements present with unique challenge to optimize the leaf spring bush design, stiffness and material characteristics of the rubber. Traditionally, bushes with varying degree of stiffness are selected, manufactured and tested on vehicle and the best one is chosen depending on the requirements. However, this approach is costly, time consuming and iterative. In this study, the stiffness targets required for the bush were analysed using static and dynamic load cases using virtual simulation (MSC.ADAMS).
2017-03-28
Technical Paper
2017-01-1371
Hao Pan, Xuexun Guo, Xiaofei Pei, Xingzhi Dong
Abstract Brake pedal feel plays an important role in the driver's comprehensive subjective feeling when braking, which directly affects the active safety and riding comfort of passenger car. A systematical mathematical model of the vehicle brake system is built in according with the structure and system characteristics of hydraulic servo brake system. A complete hydraulic servo brake system simulation model composed of brake pedal, vacuum booster, brake master cylinder, brake pipe, brake wheel cylinders, brake calipers is established in AMESim. The effects of rubber reaction plate stiffness, rubber valve opening, brake master cylinder piston, brake caliper, brake pipe deformation and friction liner deformation on brake pedal feel are considered in this model. The accuracy of this model is verified by real road vehicle tests under static and dynamic two different conditions.
2017-03-28
Technical Paper
2017-01-0239
Seth Bryan, Maria Guido, David Ostrowski, N. Khalid Ahmed
While excluding component changes, it is desirable to find methods to increase electric vehicle (EV) driving range and reduce performance variability of Plug-in Hybrid Electric Vehicles. One strategy to improve EV range could be to increase the charge power limit of the traction battery, which allows for more brake energy recovery. This paper investigates how increasing the charge power limit could affect EV range in real world usage with respect to driving behavior. Big Data collected from Ford employee vehicles in Michigan was analyzed to assess the impact of regenerative braking power on EV range. My Ford Mobile data was used to find correlation to drivers nationwide based on brake score statistics. Estimated results show incremental improvements in EV range from increased charge power levels. Subsequently, this methodology and process could be applied to make future design decisions based on evolving driving habits.
2017-03-28
Technical Paper
2017-01-1487
Russ Norton, Ben Bulat, Ahmed Mohamed
The RLM algorithm seeks to resolve the tradeoff of high damping rates required to control the loads and the need for lower damping forces to improve secondary ride. As the base active damping forces are increased to control the loads, ride benefits of the system are diminished. To ensure the best possible outcome, the team sought to reduce the tradeoffs by looking for a way to switch the damping force fast enough to manage the loads without affecting secondary ride. The RLM algorithm is designed to manage the road loads when driving through potholes. The algorithm detects the presence of a pothole based on individual suspension velocity and direction. When the wheel enters the pothole, the suspension velocity increases quickly while traveling downward (suspension rebound travel) into the pothole.
2017-03-28
Technical Paper
2017-01-1504
Peter Tkacik, Zachary Carpenter, Aaron Gholston, Benjamin James Cobb, Sam Kennedy, Ethan Blankenship, Mesbah Uddin, Surya Phani Krishna Nukala
Wind tunnel aerodynamic testing involving rolling road tire conditions can be expensive and complex to set up. Low cost rolling road testing can be implemented in a 0.3m2 Eiffel wind tunnel by modifying a horizontal belt sander to function as a moving road. This sander is equipped with steel supports to hold a steel plate against the bottom of the wind tunnel to stabilize the entire test section. These supports are bolted directly into the cast iron sander frame to ensure minimal vibrational losses or errors during testing. The wind tunnel design at the beginning of the project was encased in a wooden box which was removed to allow easier access to the test section for installation of the rolling road assembly. The tunnel was also modified to allow observers to view the testing process from various angles.
2017-03-28
Technical Paper
2017-01-1284
Khushal Ahmad, Monis Alam
With the ever increasing number of vehicles on road and the rise of the electric and automated vehicles, it is important to minimise the consumption of energy by each vehicle, regenerative braking is in wide use today, however, the research in the field of regenerative suspension is limited. The regenerative suspension has huge capabilities in power generation especially on third world roads having rather bumpy rides. A huge amounts of energy is wasted in shock absorbers due to friction. This study emphasizes on the implementation of the energy present in the suspension system by replacing the Shock Absorber with a Energy transfer system Involving Hydraulic cylinder, Hydraulic Motor and Dynamo. The energy which is usually lost as heat due to friction in conventional Suspension is used to drive a dynamo through Hydraulic System designed in this paper and electricity is generated.
2017-03-28
Technical Paper
2017-01-1551
Charlie Lew, Nath Gopalaswamy, Richard Shock, Bradley Duncan, James Hoch
Accurate, efficient, and insightful computational simulations for aerodynamics are now a fundamental requirement for the digital vehicle development process. Using detailed aerodynamics simulations of the full vehicle geometry including accurate engine bay, underbody components, suspension, brakes, and wheels, every aspect of aerodynamic design can be explored. One area that is particularly challenging for simulation methods is the rotation of the tire treads and wheels due to their close proximity and often intersection with the ground plane. Treaded tires have unique aerodynamic characteristics due to the small-scale separations and pressure gradients created by the passage of tread features past the approaching airstream. The tread can significantly affect the flow into the wheel and brake regions, affect the downstream size and direction of the wheel wake, and in turn affect the aerodynamic drag of the entire vehicle.
2017-03-28
Technical Paper
2017-01-1626
Tomas Poloni, Jianbo Lu
This paper proposes a method to make diagnostic/prognostic judgement about the health of a tire, in term of its wear, using existing sensor signals. The approach focuses on using an estimate of the effective rolling radius (ERR) of individual tires as one of the main diagnostic/prognostic features and it determines if a tire has significant wear and how long it needs to be changed or rotated. The ERR is determined from the combination of wheel speed sensor (WSS), Global Positioning sensor (GPS), the other motion sensor signals, together with the radius kinematic model of a rolling tire. The ERR estimation fits the relevant signals to a linear model and utilizes the relationship revealed in the magic formula tire model. The ERR can then be related to multiple sources of uncertainty such as the tire inflation pressure, tire loading changes, and tire wear. The estimated ERR are further processed to compute the unloaded tire radius (UTR).
2017-03-28
Journal Article
2017-01-0112
Mingming Zhao, Hongyan Wang, Junyi Chen, Xiao Xu, Yutong He
Rear-end accident is one of the most important collision modes in China, which often leads to severe accident consequences due to the high collision velocity. Autonomous Emergency Braking (AEB) system could perform emergency brake automatically in dangerous situation and mitigate the consequence. This study focused on the analysis of the rear-end accidents in China in order to discuss about the parameters of Time–to-Collision (TTC) and the comprehensive evaluation of typical AEB. A sample of 84 accidents was in-depth investigated and reconstructed, providing a comprehensive set of data describing the pre-crash matrix. Each accident in this sample is modeled numerically by the simulation tool PC-Crash. In parallel, a model representing the function of an AEB system has been established. This AEB system applies partial braking when the TTC ≤ TTC1 and full braking when the TTC ≤ TTC2.
2017-03-28
Technical Paper
2017-01-1399
Bin Wu, Xichan Zhu, Jianping Shen, Xuejun Cang, Lin li
Abstract A driver steering model for emergency lane change based on the China naturalistic driving data is proposed in this paper. The steering characteristic of three phases is analyzed. Using the steering primitive fitting by Gaussian function, the steering behaviors in collision avoidance and lateral movement phases can be described, and the stabilization steering principle of yaw rate null is found. Based on the steering characteristic, the near and far aim point used in steering phases is analyzed. Using the near and far aim point correction model, a driver steering model for emergency lane change is established. The research results show that the driver emergency steering model proposed in this paper performs well when explaining realistic steering behavior, and this model can be used in developing the ADAS system.
2017-03-28
Technical Paper
2017-01-1058
L.V. Pavan Kumar Maddula, Ibrahim Awara
Increased focus on fuel efficiency and vehicle emissions has led the automotive industry to look into low weight alternative designs for powertrain system components. These new design changes pose challenges to vehicle attributes like NVH, durability, etc. Further, the requirement of high power applications produces even more complexities. The present work explains how a potential design change of half shafts driven by a desire to reduce weight and cost can lead to NVH problems caused by half shaft resonances and explains how using multiple dynamic vibration absorbers can solve the issue to meet customer expectation while improving efficiency. With the aid of Finite Element Analysis (FEA) & optimization software, interactions between multiple DVA's on a system was understood and optimal damper parameters for effective damping was identified. The final DVA design was tested and verified on the vehicle for optimal attribute performance.
2017-03-28
Technical Paper
2017-01-1581
Jianbo Lu, Hassen Hammoud, Todd Clark, Otto Hofmann, Mohsen Lakehal-ayat, Shweta Farmer, Jason Shomsky, Roland Schaefer
This paper presents a brake control function which conducts emergency brake assistance or autonomous braking up to ABS slip ratio level after a collision is detected when a vehicle is engaged in a crash. The system is an enhancement to the ESC and ABS functions, where driver's control actions are required to initiate the brake control functions (hence, driver assistance features).. In the proposed system, the brake controls is initiated by the detected collision events.
2017-03-28
Journal Article
2017-01-0404
Anatoliy Dubrovskiy, Sergei Aliukov, Sergei Dubrovskiy, Alexander Alyukov
Currently, a group of scientists consisting of six doctors of technical sciences, professors of South Ural State University (Chelyabinsk, Russia) has completed a cycle of scientific research for creation of adaptive suspensions of vehicles. We have developed design solutions of the suspensions. These solutions allow us to adjust the performance of the suspensions directly during movement of a vehicle, depending on road conditions - either in automatic mode or in manual mode. We have developed, researched, designed, manufactured, and tested experimentally the following main components of the adaptive suspensions of vehicles: 1) blocked adaptive dampers and 2) elastic elements with nonlinear characteristic and with improved performance.
2017-03-28
Journal Article
2017-01-0412
Mina M.S. Kaldas, Kemal Çalışkan, Roman Henze, Ferit Küçükay
Nowadays the semi-active suspension system is a challenge in the Automobile industry to improve the ride comfort performance of the vehicles. Hence, improving the vehicle ride comfort performance by using the semi-active suspension has a negative effect on the harshness performance of the vehicle. Therefore, this paper suggests a solution to improve the harshness performance of the vehicle through optimizing the damper top mount characteristics of the of the semi-active suspension system. In this study an optimization technique for optimizing the damper top mount characteristics to improve vehicle harshness is developed. The proposed optimization technique employs a new combined objective function based on ride comfort and harshness evaluation. A detailed and accurate damper top mount mathematical model is implemented inside a validated full vehicle model to provide a realistic simulation environment for the optimization study.
2017-03-28
Journal Article
2017-01-0421
Xiang Liu, Wei Chen, Ying Chen, Jing Zhao
The leaf spring has significant hysteresis characteristics due to the interleaf friction. The traditional three-link model could not simulate the hysteresis characteristics at all. According to the dynamic load test results one can find that the dynamic stiffness of leaf spring has a nonlinear relationship with the travel distance and the load frequency has a tiny influence on it. Based on the traditional three-link model, this paper proposed a simulation modeling method by introducing torsional friction on the revelute joint. The key parameters including torsional spring stiffness, friction torque preload, stiction transition velocity and max stiction deformation are optimized by combining the ADAMS, OPTIMUS and MATLAB. The comparsion analysis between the simulation and test results of front and rear leaf springs have revealed that the simulation precision is up to 92%.
2017-03-28
Journal Article
2017-01-0437
Bin Li, Subhash Rakheja
The directional and handling responses of articulated heavy vehicles are known to be somewhat less predictable, particularly under emergency-type maneuvers. This poses complex control challenges for the driver and the road safety. Moreover, the yaw stability of an articulated vehicle is very sensitive to vehicle forward velocity and cargo load, which could vary considerably. The vast majority of the active safety control strategies in the literature, however, focus on assessments of stability limits and controller considering constant forward speed. In this paper, a gain-scheduling optimal control technique is proposed for enhancing yaw stability limits of articulated commercial vehicles considering a broad range of forward speeds. For this purpose, an optimal feedback control method is used to design a family of yaw moment controllers corresponding to different vehicle velocities.
2017-03-28
Journal Article
2017-01-1554
Ajith Jogi, Sujatha Chandramohan
Over the years, commercial vehicles, especially tractor-semitrailer combinations have become larger and longer. With the increasing demand for their accessibility in remote locations, these vehicles face the problem of off-tracking, which is the ensuing difference in path radii between the front and rear axles of a vehicle as it maneuvers a turn. Apart from steering the rear axle of the semitrailer, one of the feasible ways of mitigating off-tracking is to shift the fifth wheel coupling rearwards. However, this is limited by the distribution of the semitrailer’s load between the two axles of the tractor; any rearward shift of the fifth wheel coupling results in the reduction of the total static load on the tractor’s front axle and hence available traction. This may in turn lead to directional instability of the vehicle. In the present work, a new model of the fifth wheel coupling is proposed which the authors call Split fifth wheel coupling (SFWC).
2017-03-28
Technical Paper
2017-01-1466
Claudia De La Torre, Ravi Tangirala, Michael Guerrero, Andreas Sprick
Studies in the EU and the USA found higher deformation and occupant injuries in frontal crashes when the vehicle was loaded outboard (frontal crashes with a small overlap). Due to that, in 2012 the IIHS began to evaluate the small overlap front crashworthiness In order to solve this problem. A set of small overlap tests were carried out at IDIADA’S passive safety laboratory and the importance of identifying the forces applied in each structural element involved in small overlap crash were determined. One of the most important structural elements in the small overlap test is the wheel. Its interaction in a small overlap crash can modify the vehicle interaction at the crash, which at the laboratory the interaction is with a barrier. That interaction has a big influence at the vehicle development and design strategy. In order to study and understand in a better way the wheel kinematics and separation strategy, IDIADA developed with HATCI a small overlap sled test.
2017-03-28
Journal Article
2017-01-1482
Jens Dornhege, Simon Nolden, Martin Mayer
The layout of a vehicle steering system has to resolve a compromise. While it is important for lateral vehicle control to feel steering torque feedback of lateral tire to ground interaction, disturbing forces shall not be present in the feedback steering torque. These disturbing forces can result from road irregularities, wheel rotor imbalance, suspension asymmetry caused by production tolerances, wear or impacts, and additional vehicle internal forces, e.g. the steered wheels also driven by the engine or braked. In general these disturbances are reduced by an optimization of the suspension geometry to decrease the impact of the unintended forces on the steering system. The remaining disturbance is controlled to an acceptable level via force feedback sensitivity calibration of the steering system, what in return influences the intended driver sensitivity to feel lateral tire forces.
2017-03-28
Technical Paper
2017-01-1488
Srinivas Kurna, Ruchik Tank, Riddhish Pathak
The job of a suspension system is to maximize the friction between the tires and the road surface, to provide steering stability with good handling and to act as a cushioning device ensuring the comfort of the driver & passengers. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. Almost all heavy duty vehicles use inverted type suspension system which is also called as bogie type suspension system. The design of this type of suspension is a complex and difficult science which has evolved over many years. It was recognized very early in the development of suspensions that the interface between vehicle body and wheel needed some sort of cushioning system to reduce the vibration felt as the vehicle moved along. This was already part of road coach design and took the form of leaf (laminated) steel springs mounted on the axles, upon which the vehicle body rested.
2017-03-28
Technical Paper
2017-01-1480
Zhenfeng Wang, Mingming Dong, Yechen Qin, Feng Zhao, Liang Gu
Abstract: The study of controllable suspension properties special in the characteristics of improving ride comfort and road handling is a challenging task for vehicle industry. Currently, since most suspension control requires the observation of unmeasurable states, how to accurately acquire the states of a suspension system attracts more attention. To solve this problem, a novel approach interacting multiple mode Kalman Filter (IMMKF) is proposed in this paper. Suspension system parameters are crucial for the performance of state observers. Uncertain suspension system parameters in various conditions, e.g. due to additional load, have significant effect on state estimation. Simultaneously, state transition among different models may be happened on the condition of varying system parameters.
2017-03-28
Journal Article
2017-01-1489
Duanxiang Zhang, Bo Lin, Ahmet Kirli, Chinedum Okwudire
Electric Power Assist Steering (EPAS) is widely adopted in modern vehicles to reduce steering effort. EPAS has been suffering from reliability issues of electrical and/or electronic (E/E) components, the failure of which may cause EPAS shutdown. In the event of EPAS failure, power assist becomes unavailable and the steering system reverts to a fully manual state, leading to excessive steering torque demands from drivers to maneuver the vehicle at lower speeds, usually under 30 mph. This situation has resulted in dozens of reported crashes and several OEM safety recalls in the past few years. Inspired by recent work which utilizes independent driving torque of in-wheel-motor vehicles to reduce steering torque, this paper proposes the use of Differential Braking Assist Steering (DBAS) to alleviate steep increases in steering torque upon EPAS failure. DBAS only requires software upgrades and minimal hardware modification, which is preferable for a backup system.
2017-03-28
Journal Article
2017-01-1485
Mikihiro Hiramine, Yoshitaka Hayashi, Takashi Suzuki
In recent years, Power steering system has been replaced to electric power steering (EPS), in order to achieve better fuel consumption and reduce exhaust emissions and now EPS also plays important roles in driving assistance such as active safety and automated parking, so its number is expected to increase more and more. EPS is one of many automotive applications that requires a high level of safety. Since installation of EPS system started from light weight vehicles, fail-safe concept of the EPS system is reverting to manual steering mode if a failure occurs by any chances in order to maintain steering control. Now, EPS is expanding to heavier vehicles such as SUVs and Pickup Trucks, which require higher output motor power, with the advance in the power electronics technology. As the weight of the vehicle with the EPS increases, there is increase in the importance of an argument about avoidance of a sudden loss of electric power steering.
2017-03-28
Journal Article
2017-01-0411
Yuming Yin, Subhash Rakheja, Jue Yang, P-E. Boileau
Abstract This study is aimed at characterizing the nonlinear stiffness and damping properties of a simple and low cost design of a hydro-pneumatic suspension (HPS) that permits entrapment of gas into the hydraulic fluid. The mixing of gas into the oil yields highly complex variations in the bulk modulus, density and viscosity of the hydraulic fluid, and the effective gas pressure, which are generally neglected. The pseudo-static and dynamic properties of the HPS strut were investigated experimentally and analytically. Laboratory tests were conducted to measure responses in terms of total force and fluid pressures within each chamber under harmonic excitations and nearly steady temperature. The measured data revealed gradual entrapment of gas in the hydraulic fluid until the mean pressure saturated at about 84% of the initial pressure, suggesting considerably reduced effective bulk modulus and density of the hydraulic fluid.
2017-03-28
Technical Paper
2017-01-0410
Aref M. A. Soliman
Abstract Although active suspension improved vehicle ride comfort, their two main drawbacks are the required high component costs and energy input levels for active suspension. The semi-active and twin accumulator suspensions are proposed which addresses these two drawbacks. Ride performances for passive, twin accumulator and semi-active are examined theoretically using half vehicle model. The power consumed in rolling resistance and power dissipation in suspension for passive, twin accumulator and semi-active suspension systems are evaluated. The effect of road disturbance on the vehicle ride performance for twin accumulator and semi-active suspension systems is studied. The rolling resistance power losses are also investigated. The results showed that the optimum twin accumulator suspension system over all road roughness/speed conditions would have adaptable spring stiffness and damping coefficients which could be changed depending on the road conditions.
2017-03-28
Journal Article
2017-01-0419
Yuliang Yang, Yu Yang, Ying Sun, Jian Zeng, Yunquan Zhang
Abstract In addition to ride comfort, handling stability and other conventional vehicle performances, we should also focus on other aspects of performance to a center axle trailer combination, such as the maximum stable side-inclination, the anti-rolling stability, the lateral stability and so on. Based on the finite element method, a rigid-flexible coupling model for the truck combination was built and analyzed in the multi-body environment (ADAMS), in which the key components of the chassis and cab suspension were treated as flexible bodies. A series of simulations were carried out to evaluate the lateral stability of the center axle trailer in accordance with the relevant regulations of the vehicle. The influence of design variables on the lateral stability was studied by an experiment. Furthermore, in order to improve the lateral stability of the trailer combination, the optimal design was obtained by the co-simulation of the ADAMS/Car, iSIGHT and Matlab.
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