Browse Topic: Slip

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Evaluating Passenger Car Tyre Performance: Lateral and Longitudinal Dynamics in Varied Testing Conditions2026-26-0578To be published on 01/16/2026
The lateral and longitudinal dynamics of passenger car tyres are crucial for vehicle safety, handling and stability, thus having a direct influence on the braking, acceleration, and cornering performance of a vehicle. This study investigates the influence of key input parameters, namely inflation pressure, vertical load, and inclination angle, on the tyre behaviour using a dual approach: Indoor testing using a Flatbed machine for controlled conditions and Outdoor testing using a traction trailer for real-world evaluations. Lateral dynamics is evaluated across a range of slip angles to analyse lateral force and aligning moment characteristics. The quantification of the influence of inclination angle, inflation pressure, and load on lateral characteristics is done by evaluating the cornering stiffness and aligning stiffness. The indoor tests are conducted in both sweep and steady-state modes. The outdoor tests rely solely on sweep testing due to practical limitations. The longitudinal
Sethumadhavan, Arjun, Duryodhana, Dasari, Tomer, Avinash, Ghosh, Prasenjit, Mukhopadhyay, Rabindra
"Parametric Evaluation of Rolling Resistance in Bias & Radial Tyres and influence of key operational parameters under varying conditions."2026-26-0606To be published on 01/16/2026
Tyre rolling resistance is a fundamental parameter in automotive engineering, directly impacting vehicle fuel efficiency and overall performance. The Rolling Resistance Coefficient (CRR) is influenced by tyre construction, material properties, and operational conditions such as inflation pressure, vehicle speed, load, ambient temperature, and road surface roughness. This study investigates the influence of critical parameters—including test speed, inflation pressure, load, temperature, and slip angle—on the rolling resistance of tyres of various sizes. While previous research has predominantly focused on radial tyres, this paper extends the analysis to include bias-ply tyres, which remain widely used in ASEAN countries, including India. The findings aim to offer valuable insights for policymakers and researchers by examining the behaviour of bias tyres under real-world conditions. Special focus is given to the influence of slip and camber angles, with experiments conducted on passenger
Joshi, Amol, Khairatkar, Vyankatesh, Belavadi Venkataramaiah, Shamsundara
Design Robustness of Electronic Locking Differential for enhanced off-road performance2026-26-0502To be published on 01/16/2026
The Electronic Locking Differential (ELD) is a critical component for enhancing off-road vehicle performance by ensuring optimal traction in challenging terrains. This paper addresses intermittent engagement issues observed in the ELD system during off-road trials, which impacted its reliability and functionality. It presents a comprehensive study of design robustness improvements implemented to resolve these concerns and optimize the ELD’s performance, ensuring enhanced customer satisfaction in demanding off-road environments. The analysis begins with identifying factors contributing to the intermittent engagement and disengagement of the ELD system upon actuation. These factors include residual magnetism, material properties, temperature effects, and the stack-up characteristics of transfer path components under various boundary conditions. To address these challenges, three key design modifications were introduced: (1) reduction of residual magnetism through an increased air gap
S, Mohd Imtiaz, AP, Baaheedharan, Ghumare, Dheeraj, Kanagaraj, Pothiraj, Jain, Saurabh Kumar
Optimizing Stick Slip Performance in Automotive Interiors by Material Selection, Additives, and Design Strategies2026-26-0325To be published on 01/16/2026
The automotive industry is highly competitive, especially in terms of design and perceived quality. The use of hard plastics with a high gloss finish is driven by styling trends and the push towards zero gaps, making interfaces critical. In-cabin mood lighting is another feature being offered as a theme for interiors. Dashboard or cockpit designs often incorporate a significant amount of polycarbonate-acrylonitrile butadiene styrene (PC-ABS) and polycarbonate (PC). These materials provide strength and design flexibility but have the disadvantage of material incompatibility when used together, leading to stick-slip phenomena. Traditionally, felt tapes were used as interface isolation to solve this problem, but this increased manufacturing costs and assembly complications. The study focuses on the stick-slip phenomenon and material interface modifications. Specifically, it examines selecting the right surface finish on one side of the PC & PC-ABS interface to change adhesion and friction
Mohammed, Riyazuddin, R, Prasath, Rahman, Shafeeq
Optimized Panel Design for Reducing Seal Squeak and Chucking in Door & Body Seals2026-26-0341To be published on 01/16/2026
Quieter cabins in an automobile are the new era, they provide customers with pleasurable driving experience. Squeak and Rattle are spoil sport for any OEM that aim to improvise customer driving experience. Their nonlinear nature makes it difficult to formulate design frontloading methods. The issue of seals rubbing against the body & door interface is a clear sign of seal squeak & seal chucking. Seals are applied with anti-friction coatings to avoid stick slip phenomena between EPDM and painted panel. Primary root cause for seal squeak is coating erosion. The challenge lies in determining whether the body or the closure side contributes to the seal issue. This paper presents a distinctive approach for identifying the seal squeaking noise and enriches on the new modelling methods for seal interaction with door and body interfaces using FE software. The proposed method was able to highlight the locations along the door-body interface for squeak noise. The approach for reducing the
H, RAVISHANKAR, C M, MITHUN, MICHAEL STEPHAN, NAVIN ESTAC RAJA, Mohammed, Riyazuddin
Nonlinear Joint Dynamic Estimator of Sideslip Angle and Tire-Road Peak Adhesion Coefficient Based on Improved Brush Tire Model2024-01-703312/13/2024
The sideslip angle and tire-road peak adhesion coefficient (TRPAC) are crucial parameters for intelligent active safety systems in automobiles. The accuracy and real-time estimation of these parameters significantly affect control effectiveness. And there is a strong coupling between the two parameters, which brings great challenges to the joint estimation. This paper proposes a nonlinear dynamic estimator that pre-estimates tire lateral force to achieve synchronous estimation of sideslip angle and TRPAC. Additionally, to cope with sudden changes in road adhesion condition, a TRPAC preliminary estimation optimization algorithm is introduced. Moreover, an adaptive gain adjustment algorithm for the sideslip angle estimator is implemented to address large lateral excitation conditions. Simulation results on various road surfaces and under various lateral excitation conditions demonstrate that the proposed joint estimator enables accurate and rapid estimation of sideslip angle and TRPAC.
Zhao, Wenrui, Leng, Bo, Han, Yinfeng, Yu, Zhuoping, Xiong, Lu
Design of a Model-Based Optimal Multivariable Control for the Individual Wheel Slip of a Two-Track Vehicle2023-01-121906/26/2023
The concept of autonomous driving has become increasingly relevant. This is why innovative drive concepts for motor vehicles need to be developed. Therefore, a model-based optimal multivariable control for the wheel slip is presented in this paper. This allows to specify the slip, and thus the tire force, individually for each wheel. The plant model consists of a planar and stiff multibody two-track model of a vehicle, a complex tire model as well as a simple air resistance and motor model. In addition, the contact forces of the individual wheels are calculated dynamically. A special feature of the multibody model is that the vehicle's position variables are defined by integrating the velocity variables. The linearized model derived from the nonlinear model is used to design a linear optimal static state space controller (LQR) including reference and disturbance feedforward. The contact point velocities of the tires are defined as the controlled variables, since they are proportional
Irmer, Marcus, Rosenthal, Robert, Nüßgen, Alexander, Degen, René, Thomas PhD, Karin, Ruschitzka PhD, Margot
Controller design for path tracking of autonomous vehicle incorporating four-wheel steering system2022-01-034603/29/2022
This research aims to model and assess autonomous vehicle controller while including a four-wheel steering and longitudinal speed control. Such a modeling process simulates human driver behavior with consideration of real vehicle dynamics’ characteristics during standard maneuvers. However, a four-wheel steering control improves vehicle stability and maneuverability as well. A two-degree of freedom bicycle model, lateral deviation and yaw angle, is constructed to describe vehicle dynamics’ behavior. Moreover, a comprehensive traction model is implemented which includes an engine, automatic transmission, and non-linear magic formula tire model for simulation of vehicle longitudinal dynamics. A combination of PID longitudinal controller and fuzzy lateral controller are implemented simultaneously to track the desired vehicle path while minimizing lateral deviation and yaw angle errors. Then, A LQR based rear steering controller is introduced to represent a performance improvement over
Gafar, Ibrahim, Oraby, Walid, Aly, Mahmoud Atef
Event-triggered Adaptive Robust Control for Lateral Stability of Steer-by-wire Vehicles with Abrupt Nonlinear Faults2022-01-111203/29/2022
Owing to the fact that autonomous vehicles equipped with active front steering (AFS) have the features of time-varying, uncertainties, high rate of fault and high burden on the in-vehicle networks, this article studies the adaptive robust control problem for improving steer-by-wire (SBW) vehicles lateral stability in the presence of abrupt nonlinear faults. Firstly, a robust H∞ controller, as an upper-level controller, is designed to obtain the corrected steering angle for driving both the yaw rate and the sideslip angle to achieve their desired values. Takagi-Sugeno (T-S) fuzzy modeling approach which has shown the extraordinary ability in coping with the issue of nonlinear is applied to deal with the challenge of the changing longitudinal velocity. The output of upper controller can be calculated by parallel-distribute-compensation (PDC) scheme. Then, an event triggered adaptive fault tolerant lower controller is proposed to track the desired front wheel steering angle offered by the
zheng, gong, Xie, Zhengchao, Zhao, Jing
Hierarchical Vehicle Stability Control Strategy Based on Unscented Kalman Filter Estimation2022-01-034303/29/2022
High-speed vehicle is prone to instability under bad road conditions, causing many safety accidents such as tail-flicking and overturning. Stability control could assist vehicle to drive safely and stably by adjusting the additional yaw moment. However, most of the existing stability control strategies directly invoke the information of the sideslip angle of the centroid that is difficult to obtain on the vehicle, and carry out complex controller design, which deviates from the actual application. In order to achieve a complete set of stability control architecture oriented to practical applications, this paper designs a hierarchical vehicle stability control strategy based on differential braking and state estimation technology. Firstly, a model oriented to state estimation and controller design is built according to the vehicle's motion state; Secondly, the sideslip angle of the centroid is accurately estimated through the unscented Kalman filter algorithm; Subsequently, the sliding
Zhang, Jian, Jiang, Hongwei, Li, Linrun, Liu, Qiuzheng, Wang, Yu, Liu, Jinbo, Gao, Yuan, Chen, Zhicheng
Speed Limiter Using Disturbance Observer2021-01-010204/06/2021
This paper suggests disturbance observer which improves performance of speed limit assist control. The nonlinear disturbance observer was designed so that disturbance caused by parameter and load uncertainties is able to be estimated exponentially. With the contribution of the observer, feed-forward and integral controllers can be omitted while improving steady-state error elimination and overshoot reduction. The acceleration observer is also designed to reduce the effect of wheel slip and changing slope. The performance of the controllers has been verified not only on flat roads, but also on wave road and rapidly changing ramps.
Son, Huiun, Jo, Kyuhwan, Kim, Sangjoon, Cho, Jinkyeom, Jeon, Sungbae
Slip Speed and Drive Torque Planning of Multivariable Controller for an Electrified Vehicle with Dual Clutch Transmission2020-01-224309/15/2020
Demand for electrified vehicles is increasing due to increased environmental pollution regulations and interest in highly efficient vehicles. According to these demands, research on electrified vehicles equipped with Dual Clutch Transmission (DCT) has been actively conducted for the purpose of improving energy efficiency of electrified powertrain, maximizing acceleration performance, and increasing maximum speed. However, since DCT requires clutch to clutch shifting, it is difficult to control drive torque and slip speed using two clutch actuators and a power source input. In order to solve this, a study on a multivariable shift controller has been conducted. However, this study chose a heuristic planning method to control the two outputs. However, since the slip speed and drive torque are coupled, it is necessary to tune the reference for every shift scenario, as well as create unnecessary control inputs or degrade shift control performance. Therefore, this study proposes a reference
Kim, Dong-Hyun, Choi, Seibum
Injectable Gel Helps Heart Muscle RegenerateTBMG-3686205/01/2020
In mammals, including humans, the cells that contract the heart muscle and enable it to beat do not regenerate after injury. After a heart attack, there is a dramatic loss of these heart muscle cells, and those that survive cannot effectively replicate. With fewer of these contractile cells, known as cardiomyocytes, the heart pumps less blood with each beat, leading to the increased mortality associated with heart disease.
New Control Method of Four-Wheel Independent Driving Electric Vehicles for Anti-Slip Purposes2020-01-142004/14/2020
The performance of electric vehicles could be enhanced by more flexible drivetrain configurations combined with advanced control method. Based on the four wheel independent driving and front and rear axle modular steering configuration, which was proposed by our research group last year, the problem of slippery under close-to-limit conditions are further discussed and simulated. A new torque vectoring method based on obtainable parameters and variables in real driving situations is introduced to reduce the sideslip when turning on low friction coefficient surfaces or with high speed. This method is developed from a comprehensive index, which reflects the stability and maneuverability, by adding additional torques when stability could not be compensated enough by basic torque vectoring. Besides, an improvement of adding a simu-Torsen differential mechanism is made to the model of the vehicle, which enables another control method with the same purpose as before. This method is combined
Liu, Chen, Zheng, Gangtie
Electronic Differential Control of Rear-Wheel Independent-Drive Electric Vehicle10-04-01-000412/02/2019
To track desired slip ratios and desired longitudinal speeds at the centers of driving wheels in the curve, this article proposes a hierarchical structured electronic differential control (EDC) of rear-wheel independent-drive electric vehicle (EV). In the high-level control, a fuzzy algorithm-based coefficient is computed according to the driver’s emotional intention of acceleration. The fuzzy algorithm-based coefficient is used to correct the desired driving torque of vehicle transmitting to the medium-level control. In the medium-level control, an optimization algorithm is developed to allocate the desired torques with requirement of as much accurate yaw moment as possible by the desired driving torque of the vehicle and yaw moment. And the desired longitudinal speeds at the centers of the rear left and right wheels are corrected twice, respectively, by Ackermann steering principle, considering the slip angle of the wheel and yaw moment. Based on the desired torques and desired
He, Ren, Yun, Hang
Algorithm Gives Robots a Faster GraspTBMG-3561512/01/2019
A robot that's sorting through a bin of objects and attempting to get a good grasp on one of them is performing a computationally taxing maneuver. Before even attempting the move, it must calculate a litany of properties and probabilities such as the friction and geometry of the table, the pen, and its two fingers, and how various combinations of these properties interact mechanically based on fundamental laws of physics.
An Experimental Study to Evaluate the Droplet Impinging Erosion Characteristics of an Icephobic, Elastic Soft Surface2019-01-199706/10/2019
Elastic soft material/surface, such as Polydimethylsiloxane (PDMS), is a perspective, useful and low-cost hydrophobic and icephobic coating. While it has been reported to have good mechanical durability, its erosion durability under the high impacting of water droplets pertinent to aircraft inflight icing phenomena has not been explored. In this study, the droplet imping erosion characteristics of an icephobic PDMS surface/material is evaluated systematically upon the dynamic impinging of water droplets at different impact velocities (~ up to 75m/s), in comparison with other state-of-the-art icephobic materials/surfaces, such as superhydrophobic surface (SHS) and slippery liquid-infused porous surface (SLIPS). Surprisingly, the contact angle (CA) of the elastic PDMS is shown to have an over 20° increase (from 105° to 128°), which represents better hydrophobicity, after the erosion test which is mainly contributed to the higher roughness of the eroded PDMS surface. As for the
Ma, Liqun, Zhang, Zichen, Liu, Yang, Hu, Hui
A Novel Heating-Coating Hybrid Strategy for Wind Turbine Icing Mitigation2019-01-202906/10/2019
The electro-thermal method is most commonly used for wind turbine anti-/de-icing. The upmost drawback of such systems is the high power consumption. In the present study, we proposed to use a durable slippery liquid-infused porous surface (SLIPS) to effectively reduce the power requirement of the heating element during the anti-/de-icing process. The explorative study was conducted in the Icing Research Tunnel at Iowa State University (ISU-IRT) with a DU91-W2-250 wind turbine blade model exposed under severe icing conditions. During the experiments, while a high-speed imaging system was used to record the dynamic ice accretion process, an infrared (IR) thermal imaging system was also utilized to achieve the simultaneous surface temperature measurements over the test model. In comparison to the traditional electrical heating strategies to brutally heat massive area of entire turbine blades, a novel heating-coating hybrid strategy, i.e., combining a leading-edge (LE) heating element to
Gao, Linyue, Ma, Liqun, Liu, Yang, Hu, Hui
An Experimental Investigation of a Wind-Driven Water Droplet over the Slippery Liquid Infused Porous Surface2019-01-195106/10/2019
The promising anti-icing performance of the slippery liquid infused porous surface (SLIPS) has been recently demonstrated for various engineering applications. The runback icing for aircraft and wind turbines could be effectively mitigated considering the timely removal of water droplet by the wind shearing force due to the low adhesion on the SLIPS. In this study, the flow field both inside and around the wind-driven droplet over the SLIPS was experimentally investigated by using Particle Image Velocimetry (PIV) technique. Previous studies majorly focus on the internal flow pattern before the droplet incipient motion. In this study, the flow field inside a moving droplet was firstly investigated. As a result of the low surface adhesion of the SLIPS, droplet oscillations were eliminated and the droplet internal flow field could be corrected from the optical distortion. Besides the discussion on the wind speed, the droplet viscosity was also studied by varying the water concentration of
Ma, Liqun, Hu, Hui
Event Data Recorder Performance during High Speed Yaw Testing Subsequent to a Simulated Tire Tread Separation Event2019-01-063404/02/2019
This paper presents event data from the Sensing and Diagnostic Module (SDM) of a 2004 Chevrolet Malibu during high speed yaw testing. Yaw tests were performed using tires that were intact and tires that had the tread removed. The tires that had the tread removed were placed at various wheel positions on the vehicle (e.g. leading side - front, leading side -rear, trailing side - rear). This testing simulates the loss of control phase subsequent to a tread separation. Speeds up to 117 km/h (72.9 mph) were achieved. A simple electro-mechanical device was incorporated to the dynamic testing to simulate a low-severity non-deployment event that triggered the recording of pre-crash data by the SDM. The SDM data from the tests was imaged and compared to reference data from vehicle-mounted instrumentation recording wheel speed, steering angle, measured vehicle sideslip angle and GPS calculated over the ground speed. This paper examines the dynamic effect of high sideslip angles and changes to
Bortles, William, Koch, Daniel, Beauchamp, Gray, Pentecost, David, Rayburn, George, Hostetler, Ryan
Model-Based Approaches in Developing an Advanced Aftertreatment System: An Overview2019-01-002601/15/2019
Cummins has recently launched next-generation aftertreatment technology, the Single ModuleTM aftertreatment system, for medium-duty and heavy-duty engines used in on-highway and off-highway applications. Besides meeting EPA 2010+ and Euro VI regulations, the Single ModuleTM aftertreatment system offers 60% volume and 40% weight reductions compared to current aftertreatment systems. In this work, we present model-based approaches that were systematically adopted in the design and development of the Cummins Single ModuleTM aftertreatment system. Particularly, a variety of analytical and experimental component-level and system-level validation tools have been used to optimize DOC, DPF, SCR/ASC, as well as the DEF decomposition device. The highlights of this work can be summarized as follows: a). internal dosing is more efficient than external dosing to control HC slip; High CPSI DOCs show better HC oxidation performance at high SV due to enhanced mass transfer; b). the adopted advanced
Su, Changsheng, Brault, Joseph, Munnannur, Achuth, Liu, Z. Gerald, Milloy, Sean, Harinath, Arvind, Dunnuck, David, Federle, Ken
Boundary Layer Dynamics and Sound Generation2018-01-190010/05/2018
In recent years, characteristic structures in the boundary layer of high-load contacts such as brakes have been reported, which substantially influence the dynamics of the tribological contact. Usually, local assumptions concerning the friction behavior of these patches are used to reach global conclusions about the brake system. Several numerical methods (e.g. Cellular Automata) have been developed which employ such assumptions. The validation of these methods through measurement data tends to be laborious and costly. Sprag-Slip elements are friction elements that are exclusively subjected to static friction, never undergoing sliding friction. Implementing such elements on a mesoscopic scale, it is possible to generate global descriptions of macroscopic stick and slip friction phenomena. Locally, these Sprag-Slip elements are similar to the patch structures in the tribological boundary layer of brakes. The Sprag-Slip elements are suitable for describing the basic physics in the
Recke, Bastian, Ostermeyer, Georg
GPS Enabled Semi-Autonomous RobotTBMG-2890405/01/2018
The primary objective of this research is to integrate GPS and local sensory data to allow a robot to operate semi-autonomously outside of a laboratory environment. The Pioneer 3-AT, a robust platform capable of operating in the outdoors, is utilized in this project. The P3-AT has acoustic sensors that can calculate distances to obstacles and encoders that calculate how much each wheel has turned. In a laboratory environment, sensory and encoder information can be used to triangulate position or measure distance and direction traveled from a known starting point. Operating outdoors limits the effectiveness of both systems as the obstacles are not known and wheels can often slip and slide on different surfaces. This necessitates external data to determine the location of the robot. GPS was chosen to provide that data. GPS, acoustic, and encoder data were integrated within MATLAB and provided control signals to the robot.
Vehicle Sideslip Angle Estimation: A Review2018-01-056904/03/2018
Vehicle sideslip angle estimation is of great importance to the vehicle stability control as it could not be measured directly by ordinary vehicle-mounted sensors. As a result, researchers worldwide have carried out comprehensive research in estimating the vehicle sideslip angle. First, as the attitude would affect the acceleration information measured by the IMU directly, different kinds of vehicle attitude estimation methods with multi-sensor fusion are presented. Then, the estimation algorithms of the vehicle sideslip angle are classified into the following three aspects: kinematic model based method, dynamic model based method, and fusion method. The characteristics of different estimation algorithms are also discussed. Finally, the conclusion and development trend of the sideslip angle estimation are prospected.
Liu, Wei, Xiong, Lu, Xia, Xin, Yu, Zhuoping
Vehicle Sideslip Angle Estimation Considering the Tire Pneumatic Trail Variation2018-01-057104/03/2018
Vehicle sideslip angle is significant for electronic stability control devices and hard to estimate due to the nonlinear and uncertain vehicle and tire dynamics. In this paper, based on the two track vehicle dynamic model considering the tire pneumatic trail variation, the vehicle sideslip angle estimation method was proposed. First, the extra steering angle of each wheel caused by kinematics and compliance characteristics of the steering system and suspension system was analyzed. The steering angle estimation method was designed. Since the pneumatic trail would vary with different tire slip angle, distances between the center of gravity (COG) and front&rear axle also change with the tire slip angle. Then, based on the dynamic pneumatic trail and estimated steering angle, we modified the traditional two track vehicle dynamic model using a brush tire model. This model matches the vehicle dynamics more accurately. In addition, we designed two extended Kalman filters (EKF) based on the
Xia, Xin, Xiong, Lu, Lin, Xuefeng, Yu, Zhuoping
A Computational and Experimental Investigation into the Effects of Debris on an Inverted Double Wing in Ground Effect2018-01-072604/03/2018
Cars in several motor sports series, such as Formula 1, make use of multi-element front wings to provide downforce. These wings also provide onset flows to other surfaces that generate downforce. These elements are highly loaded to maximise their performance and are generally operating close to stall. Rubber debris, often known as marbles, created from the high slip experienced by the soft compound tyres can become lodged in the multiple elements of a front wing. This will lead to a reduction in the effectiveness of the wing over the course of a race. This work will study the effect of such debris, both experimentally and numerically, on an inverted double element wing in ground effect at representative Reynolds numbers. The wing was mounted at two different ride heights above a fixed false-floor in the Loughborough University wind tunnel and the effect of debris blockage modelled by closing sections of the gap between elements with tape. The reduction in downforce compared to the
Corfield, Emma, Hodgson, Graham, Garmory, Andrew
A Nonlinear Slip Ratio Observer Based on ISS Method for Electric Vehicles2018-01-055704/03/2018
Knowledge of the tire slip ratio can greatly improve vehicle longitudinal stability and its dynamic performance. Most conventional slip ratio observers were mainly designed based on input of non-driven wheel speed and estimated vehicle speed. However, they are not applicable for electric vehicles (EVs) with four in-wheel motors. Also conventional methods on speed estimation via integration of accelerometer signals can often lead to large offset by long-time integral calculation. Further, model uncertainties, including steady state error and unmodeled dynamics, are considered as additive disturbances, and may affect the stability of the system with estimated state error. This paper proposes a novel slip ratio observer based on input-to-state stability (ISS) method for electric vehicles with four-wheel independent driving motors. Instead of estimating vehicle speed, the proposed method employs the estimated error of motor torque as the correction output by taking the advantage of
Ren, Bingtao, Deng, Weiwen, Chen, Hong, Wang, Jinsong
A Study on Front End Auxiliary Drive(FEAD) System of 48V Mild Hybrid Engine2018-01-041404/03/2018
48V mild hybrid engine is one of major eco-friendly technology for global CO2 reduction policy. The 48V mild hybrid engine enables to operate torque boost, recuperation and ISG status by MHSG(Mild Hybrid Starter and Generator). The FEAD(Front End Auxiliary Drive) system is a very important role to transfer MHSG power to crankshaft at the mild hybrid engine. The conventional FEAD configuration is relatively simple because it transfers power from crankshaft to auxiliary drive components in one direction. But the FEAD configuration of 48V mild hybrid engine is not simple due to bidirectional power transmission between crankshaft and MHSG. For instance, in case of torque boost mode, the tight side of auxiliary belt is entry span of MHSG. On the contrary, the tight side of auxiliary belt is exit span of MHSG at recuperation mode. As a result, to continue auxiliary belt tension constantly is very difficult and important for 48V mild hybrid engine development because the change of belt
Yoon, Kibong, Hong, Jisoo, Shim, JaeYoung
Discrete Surface Dynamics: Distributed Sprag Slip Elements in Brakes2017-01-253109/17/2017
In recent years, characteristic structures in the boundary layer of high-load contacts such as brakes have been reported, which have an important impact on the dynamics of the tribological contact. Usually, local assumptions concerning the friction of these patches are used to reach global conclusions about the brake system. Several numerical methods (e.g. Cellular Automata) have been developed which make use of such assumptions. The validation of these methods through measured data tends to be laborious and costly. Sprag-Slip elements are friction elements which are typically considered to exclusively undergo static friction. Such elements have been sporadically utilized towards describing friction in brake applications. In this paper, many locally distributed Sprag-Slip elements are used to model the global dynamics of braking friction. The results show good agreement with the measured characteristics of brakes. This approach offers new possibilities for the description of global
Ostermeyer, Georg Peter, Recke, Bastian
Vehicle Stability Criterion Research Based on Phase Plane Method2017-01-156003/28/2017
In this paper, a novel method is proposed to establish the vehicle yaw stability criterion based on the sideslip angle-yaw rate (β-r) phase plane method. First, nonlinear two degrees of freedom vehicle analysis model is established by adopting the Magic Formula of nonlinear tire model. Then, according to the model in the Matlab/Simulink environment, the β-r phase plane is gained. Emphatically, the effects of different driving conditions (front wheels steering angle, road adhesion coefficient and speed) on the stability boundaries of the phase plane are analyzed. Through a large number of simulation analysis, results show that there are two types of phase plane: curve stability region and diamond stability region, and the judgment method of the vehicle stability domain type under different driving conditions is solved. Finally, different conditions of stability boundary plane database look-up tables are set up, besides, the effects of different conditions on the stability boundary’s
Liu, Wei, Xiong, Lu, Leng, Bo, Meng, Haolan, Zhang, Renxie
A Hybrid Approach to Model the Temperature Effect in Tire Forces and Moments2017-01-967603/14/2017
Tire is an integral part of any vehicle which provides contact between the vehicle and the surface on which it moves. Forces and moments generated at the tire-road interaction imparts stability and control of motion to the vehicle. These forces and moments are functions of many variables such as slip, slip angle, contact pressure, inflation pressure, coefficient of friction, temperature, etc. This paper deals with the effect of temperature on the lateral force, the longitudinal force and the self-aligning moment. The analysis is done at different tire surface temperatures such as 20°C, 40°C, and 60°C. Since the experimental set up with the mounted tire is complex and expensive, we use a hybrid approach in which we take the results from the experiments done by the researchers on a sample piece of tire rubber at various temperatures. Then, we do the steady state analysis in ABAQUS considering the variation of coefficient of friction, slip speed and the elastic modulus of rubber with
S, Bibin, Pandey, Ashok Kumar
A Droplet Size Investigation and Comparison Using a Novel Biomimetic Flash-Boiling Injector for AdBlue Injections2016-01-221110/17/2016
Increased research is being driven by the automotive industry facing challenges, requiring to comply with both current and future emissions legislation, and to lower the fuel consumption. The reason for this legislation is to restrict the harmful pollution which every year causes 3.3 million premature deaths worldwide [1]. One factor that causes this pollution is NOx emissions. NOx emission legislation has been reduced from 8 g/kWh (Euro I) down to 0.4 g/kWh (Euro VI) and recently new legislation for ammonia slip which increase the challenge of exhaust aftertreatment with a SCR system. In order to achieve a good NOx conversion together with a low slip of ammonia, small droplets of Urea solution needs to be injected which can be rapidly evaporated and mixed into the flow of exhaust gases. In most of today's solutions this process is enhanced with flow restricting mixers or longer path lengths but if these can be removed and shortened the flow losses can be reduced, leading to higher
Larsson, Peter, Lennard, Will, Andersson, Oivind, Tunestal, Per
NOx-Conversion and Activation Temperature of a SCR-Catalyst Whilst Using a Novel Biomimetic Flash-Boiling AdBlue Injector on a LD Engine2016-01-221210/17/2016
Yearly 3.3 million premature deaths occur worldwide due to air pollution and NOx pollution counts for nearly one seventh of those [1]. This makes exhaust after-treatment a very important research and has caused the permitted emission levels for NOx to decrease to very low levels, for EURO 6 only 0.4 g/kWh. Recently new legislation on ammonia slip with a limit of 10 ppm NH3 has been added [2], which makes the SCR-technology more challenging. This technology injects small droplets of an aqueous Urea solution into the stream of exhaust gases and through a catalytic reaction within the SCR-catalyst, NOx is converted into Nitrogen and Water. To enable the catalytic reaction the water content in the Urea solution needs to be evaporated and the ammonia molecules need to have sufficient time to mix with the gases prior to the catalyst. The μMist® platform technology, inspired by nature, uses heat in order to increase the fluid temperature above the required saturation temperature within its
Larsson, Peter, Lennard, Will, Dahlstrom, Jessica, Andersson, Oivind, Tunestal, Per
Vehicle Side Slip and Roll Angle Estimation2016-01-165404/05/2016
Vehicle dynamics estimation has been the subject of study for some years now. If on-board vehicle control systems can be provided with information such as side slip angle, lateral force etc. then stability of the vehicle can be improved. To estimate these dynamic variables different observers have been used e.g., sliding mode, fuzzy logic, neural networks etc. In this article the authors propose an extended Kalman filter to estimate vehicle side slip angle. Roll angle is estimated using vertical loads as input. First, a linear Kalman filter is used to filter out the vertical forces and estimate roll angle. This information is then used to estimate the vehicle side slip angle. To take into account the nonlinearities concerning lateral vehicle dynamics, Pacejka magic formula is used to model lateral forces. Estimated results are then compared with simulations, showing good accuracy.
Syed, Umair Hussain, Vigliani, Alessandro
Effect of Three Controls (Camber Angle Control, Derivative Steering Assistance Control, and Inside-Outside Wheel Braking Force and Driving Force Control in Body Slip Angle Area2016-01-166604/05/2016
In this research, we examine the three controls inside-outside wheel braking force and driving force, camber angle, and the derivative steering assistance to determine how angle differences affect cornering performance and controllability. This is accomplished by comparing body slip angle area differences in a closed loop examination of the grip to drift area using a driving simulator. The results show that inside-outside wheel braking force and driving force control in the area just before critical cornering occurs has a significant effect on vehicle stability. We also clarified that controlling the camber angle enhances grip-cornering force, and confirmed that the sideslip limit could be improved in the vicinity of the critical cornering area. Additionally, when the counter steer response was improved by the use of derivative steering assistance control in the drift area exceeding the critical cornering limit, corrective steering became easier. Moreover, the effect could be achieved
Yamaguchi, Ryo, Nozaki, Hiromichi
Aerodynamics Evaluation of Road Vehicles in Dynamic Maneuvering2016-01-161804/05/2016
A road vehicle’s cornering motion is known to be a compound motion composed mainly of forward, sideslip and yaw motions. But little is known about the aerodynamics of cornering because little study has been conducted in this field. By clarifying and understanding a vehicle’s aerodynamic characteristics during cornering, a vehicle’s maneuvering stability during high-speed driving can be aerodynamically improved. Therefore, in this study, the aerodynamic characteristics of a vehicle’s cornering motion, i.e. the compound motion of forward, sideslip and yaw motions, were investigated. We also considered proposing an aerodynamics evaluation method for vehicles in dynamic maneuvering. Firstly, we decomposed cornering motion into yaw and sideslip motions. Then, we assumed that the aerodynamic side force and yaw moment of a cornering motion could be expressed by superposing linear expressions of yaw motion parameters and those of sideslip motion parameters, respectively. Next, we conducted CFD
Okada, Yoshihiro, Nakashima, Takuji, Tsubokura, Makoto, Morikawa, Yousuke, Kouno, Ryousuke, Okamoto, Satoshi, Matsuhiro, Tanaka, Nouzawa, Takahide
Effect of Humidity on the Very High Cycle Fatigue Behavior of a Cast Aluminum Alloy2016-01-037104/05/2016
In this paper, fatigue tests on a cast aluminum alloy (AS7GU-T64) were performed under different frequencies and humidity levels. Tests conducted under conventional frequency in laboratory air have been compared to tests conducted under ultrasonic frequency in dry air, saturated humidity and in distilled water. It was observed that the highest and lowest fatigue lives correspond to ultrasonic fatigue tests in dry air and in distilled water, respectively. Unlike specimens tested at conventional frequency, all of the specimens tested at ultrasonic frequency presented a large amount of slip facets on the fatigue crack propagation fracture surface.
Li, Wenkai, Engler-Pinto, Carlos, Cui, Haitao, Wen, Weidong, Su, Xuming
Post-Impact Dynamics for Vehicles with a High Yaw Velocity2016-01-147004/05/2016
Calculating the speed of a yawing and braked vehicle often requires an estimate of the vehicle deceleration. During a steering induced yaw, the rotational velocity of the vehicle will typically be small enough that it will not make up a significant portion of the vehicle’s energy. However, when a yaw is impact induced and the resulting yaw velocity is high, the rotational component of the vehicle’s kinetic energy can be significant relative to the translational component. In such cases, the rotational velocity can have a meaningful effect on the deceleration, since there is additional energy that needs dissipated and since the vehicle tires can travel a substantially different distance than the vehicle center of gravity. In addition to the effects of rotational energy on the deceleration, high yaw velocities can also cause steering angles to develop at the front tires. This too can affect the deceleration since it will influence the slip angles at the front tires. This paper explores
Rose, Nathan A., Carter, Neal, Beauchamp, Gray
An Investigation Into New ABS Control Strategies2016-01-163904/05/2016
An investigation into two new control strategies for the vehicle Anti-lock Braking System (ABS) are made for a possible replacement of current non-optimal slip control methods. This paper applies two techniques in order to maximize the braking force without any wheel locking. The first considers the power dissipated by the brake actuator. This power method does not use slip to construct its reference signal for control. A heuristic approach is taken with this algorithm where one searches for the maximum power dissipated. This can open up easier implementation of regenerative braking concurrently with ABS on an electro-hydraulic braking system. Parameter scheduling is explored in this algorithm. The second algorithm employs the use of perturbation based Extremum Seeking Control (ESC) to provide a reference slip and a Youla controller in a negative feedback loop.
Loyola, Jonathan, Assadian, Francis
The Roles of Front and Rear Cornering Stiffness in Vehicle Directional Dynamics2016-01-165104/05/2016
The transfer functions between the variables in linear bicycle models of four wheel automobiles, the input to which is steering angle, were examined. The modal response transfer functions between all of the motion outputs, with the exception of front tire slip angle, were found to be independent of front tire cornering stiffness. It is a role unique to rear cornering stiffness to define the above mentioned transfer functions. This concept was also deductively demonstrated. The concept is true in the frequency domain, therefore, it guarantees that the amplitude ratio between two outputs and the phase difference between two outputs depends only on rear cornering stiffness. However, it is necessary to be cautious, when one applies the concept to phenomena in time domain. For example, the difference in 50 % rise time of two output variables is dependent on front tire cornering stiffness.
Minakawa, Masaaki
Analysis of Influence of Tire F and M on Improvement of Vehicle On-Center Steering2016-01-156904/05/2016
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, tread pattern shape and tread grip characteristics. First, the relationship between vehicle on-center steering performance and tire F&M characteristics was identified by comparing vehicle steering measurements and tire F&M measurements. It was found that key factor of tire related with on-center performance is aligning torque at lower slip angles. As the aligning torque at slip angle 1° increases, on-center feel is improved. Second, the influence of tire design parameters on tire aligning torque was studied through F&M finite element (FE) analysis and measurement. It was found that the aligning torque at lower slip angle increases as stiffness of the tread and sidewall decreases. However, it shows trade-off with tire cornering force
Yum, Kiho
Sideslip Angle Estimation of a Formula SAE Racing Vehicle2016-01-166204/05/2016
A method for estimating the sideslip angle of a Formula SAE vehicle with torque vectoring is presented. Torque vectoring introduces large tire longitudinal forces which lead to a reduction of the tire lateral forces. A novel tire model is utilized to represent this reduction of the lateral forces. The estimation is realized using an extended Kalman filter which takes in standard sensor measurements. The developed algorithm is tested by simulating slalom and figure eight maneuvers on a validated VI-CarRealTime vehicle model. Results indicate that the algorithm is able to estimate the sideslip angle of the vehicle reliably on a high friction surface track.
Ghosh, Jyotishman, Tonoli, Andrea, Amati, Nicola, Chen, Weitao
Modeling of Transient Aerodynamic Forces based on Crosswind Test2016-01-157704/05/2016
The aerodynamic stability of energy-saving, lightweight, and low-drag vehicles is reduced by crosswind disturbances. In particular, crosswinds cause unsteady motion in vehicles with low-drag body shapes due to aerodynamic yaw moment. To verify fluctuations in the unsteady aerodynamic forces of a vehicle, a direct measurement method of these forces in a crosswind test was established using inertial force and tire load data. The former uses an inertia sensor comprised of a gyro, acceleration sensor, and GPS sensor, and the latter uses a wheel force sensor. Noise in the measurement data caused by the natural frequency of the tires was reduced using a spectral subtraction method. It was confirmed that aerodynamic data measured in the crosswind test corresponded to wind tunnel test data. Numerical expressions were defined to model the unsteady aerodynamic forces in a crosswind. Crosswind tests were conducted under various conditions consisting of different wind patterns and test vehicle
Fukagawa, Tateru, Shimokawa, Shinnosuke, Itakura, Eiji, Nakatani, Hiroyuki, Kitahama, Kenichi
Determination of Critical Speed, Slip Angle and Longitudinal Wheel Slip based on Yaw Marks Left by a Wheel with Zero Tire Pressure2016-01-148004/05/2016
This article presents the results of an analysis of the yaw marks left by a car with normal pressure in all tires and then normal pressure in three tires and zero in one rear tire. The analysis is a continuation of research on influence of reduced tire pressure on car lateral dynamics in a passing maneuver, discussed in the SAE paper No. 2014-01-0466. Preliminary analysis of yaw marks has shown, that a wheel with zero pressure deposits a yaw mark whose geometry differs from the yaw mark made by a wheel with normal pressure based on which we could calculate: critical speed, slip angle and longitudinal wheel slip. The aim of the presented research was to analyze the yaw marks left by car with zero pressure in one rear wheel in order to check the possibility of determining the vehicle critical speed, slip angle and longitudinal wheel slip. It was reached by performing bench and road tests during which the vehicle motion parameters were recorded using GPS Data Logging System. The results
Zebala, Jakub, Wach, Wojciech, Ciępka, Piotr, Janczur, Robert
New Slip Ring System for Electromagnetic Coupling in HEV Driveline2016-01-122204/05/2016
This paper describes the slip ring system for a new hybrid system using an electromagnetic torque converter or an electromagnetic coupling. The slip ring system, which enables electric power transmission between a winding rotor and an inverter fixed on a case, is a key component for establishing a new highly efficient hybrid system. Reducing the wear of the brushes in the slip ring system is a major topic of this research. To achieve this objective, brush wear characteristics were investigated using test-piece experiments that simulated the hybrid system environment. By clarifying these characteristics, the structure of a slip ring system for reducing brush wear was identified and a wear prediction method was constructed.
Asami, Shu, Watanabe, Takao, Tominaga, Satoshi, Murakami, Akira
Fatigue Time-to-Failure Prediction Methodology for Glass (Fused Quartz) Material under Cyclic Loading2016-01-038804/05/2016
In amorphous solids such as fused quartz, the failure mechanism under cyclic loading is very different when compared to metals where this failure is attributable to dislocation movement and eventual slip band activity. Standard mechanical fatigue prediction methodologies, S-N or ε-N based, which have been historically developed for metals are rendered inapplicable for this class of material. The fatigue strength of Fused Silica or Fused Quartz (SiO2) material is known to be highly dependent on the stressed area and the surface finish. Stable crack growth in Region II of the V-K curve (Crack growth rate vs Stress intensity factor) is dependent on the competing and transitional effects of temperature and humidity, along that specific section of the stress intensity factor abscissa. Fused glass (under harsh environment conditions) finds usage in Automotive, Marine and Aerospace applications, where stress and load (both static and cyclic) can be severe. In the present work we have
Pandey, Abhijeet, Singhal, Mohit Kr., Kovacich, John, Rau, Christopher
Revisiting Vehicle Braking Longitudinal Dynamics with a Sliding Mode Controller2015-01-274809/29/2015
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. Two sliding mode controllers, one using pulse width modulation, and the other a switching controller, are designed and tested using the proposed
Haggag, Salem A.
Experimental Evaluation of Surface Morphology Characteristics During Stick-Slip Process at Low Speed Sliding Test2015-01-268509/27/2015
The present work presents evaluation of the sliding surface morphology of brake pads during stick-slip. A low-metallic (LM) and a Non Asbestos Organic (NAO) brake friction materials were 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. Delta torque divided by slip time (dT/dtslip) was the parameter used to quantify stick-slip propensity. In addition, 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. This technique was effective to quantify the differences in the sliding surface morphology during low speed braking test. Finally
Masotti, Diego, Neis, Patric, Ferreira, Ney, Gomes, Kássio, Poletto, Jean, Matozo, Luciano
A New Semi-Empirical Method for Estimating Tire Combined Slip Forces and Moments during Handling Maneuvers2015-01-911207/01/2015
Modeling the tire forces and moments (F&M) generation, during combined slip maneuvers, which involves cornering and braking/driving at the same time, is essential for the predictive vehicle performance analysis. In this study, a new semi-empirical method is introduced to estimate the tire combined slip F&M characteristics based on flat belt testing machine measurement data. This model is intended to be used in the virtual tire design optimization process. Therefore, it should include high accuracy, ease of parameterization, and fast computational time. Regression is used to convert measured F&M into pure slip multi-dimensional interpolant functions modified by weighting functions. Accurate combined slip F&M predictions are created by modifying pure slip F&M with empirically determined shape functions. Transient effects are reproduced using standard relaxation length equations. The model calculates F&M at the center of the contact patch. The developed methodology is implemented as an
Taheri, Shahyar, Wei, Terence
Three Dimensional Simulation of Flow in an Axial Low Pressure Compressor at Engine Icing Operating Points2015-01-213206/15/2015
Three-dimensional simulations of the Honeywell ALF502 low pressure compressor (sometimes called a booster) using the NASA Glenn code GlennHT have been carried out. A total of eight operating points were investigated. These operating points are at, or near, points where engine icing has been determined to be likely. The results of this study were used, in a companion paper, for further analysis such as predicting collection efficiency of ice particles and ice growth rates at various locations in the compressor. In an effort to minimize computational effort, inviscid solutions with slip walls are produced. A mixing plane boundary condition is used between each blade row, resulting in convergence to steady state within each blade row. Comparisons of the results are made to other simplified analysis. An additional modification to the simulation process is also presented. At each mixing plane (located between blade rows) it is possible to introduce ad hoc adjustments to the flow properties
Rigby, David L., Veres, Joseph, Bidwell, Colin
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