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2011-04-12
Journal Article
2011-01-0268
Jeffery R. Anderson, E. Harry Law
Traditional Electronic Stability Control (ESC) for automobiles is usually accomplished through the use of estimated vehicle dynamics from simplified models that rely on parameters such as cornering stiffness that can change with the vehicle state and time. This paper proposes a different method for electronic stability control of oversteer by predicting the degree of instability in a vehicle. The algorithm is solely based on measurable response characteristics including lateral acceleration, yaw rate, speed, and driver steering input. These signals are appropriately conditioned and evaluated with fuzzy logic to determine the degree of instability present. When the “degree of instability” passes a certain threshold, the appropriate control action is applied to the vehicle in the form of differential yaw braking. Using only the measured response of the vehicle alleviates the problem of degraded performance when vehicle parameters change.
2011-04-12
Technical Paper
2011-01-0436
Alejandra Paola Polanco, Luis Munoz
In this paper the comfort sensitivity to the variation of the inertia parameters is studied. For the theoretical approach, two computational models that predict the comfort response of a vehicle are developed and verified. These models are used to study the effect of a change on the inertial properties of the car on its comfort response. The models are developed on a commercial multi-body package and also implementing handwritten equations with a numerical integration algorithm. The influence of the inertial properties on comfort is also experimentally studied. Both approaches use two different road patterns as input generating a roll and pitch excitation. An allowed uncertainty on the inertia properties is proposed, based on the sensitivity to those properties.
2011-04-12
Journal Article
2011-01-0435
Yan Cui, Thomas Kurfess, Michael Messman
High fidelity mathematical vehicle models that can accurately capture the dynamics of car suspension system are critical in vehicle dynamics studies. System identification techniques can be employed to determine model type, order and parameters. Such techniques are well developed and usually used on linear models. Unfortunately, shock absorbers have nonlinear characteristics that are non-negligible, especially with regard the vehicle's vertical dynamics. In order to effectively employ system identification techniques on a vehicle, a nonlinear mathematical shock absorber model must be developed and then coupled to the linear vehicle model. Such an approach addresses the nonlinear nature of the shock absorber for system identification purposes. This paper presents an approach to integrate the nonlinear shock absorber model into the vehicle model for system identification.
2011-04-12
Journal Article
2011-01-0431
Mina M.S. Kaldas, Kemal Çalışkan, Roman Henze, Ferit Küçükay
Following the developments in controlled suspension system components, the studies on the vertical dynamics analysis of vehicles increased their popularity in recent years. The objective of this study is to develop a semi-active suspension system controller using Adaptive-Fuzzy Logic control theories together with Kalman Filter for state estimation. A quarter vehicle ride dynamics model is constructed and validated through laboratory tests performed on a hydraulic four-poster shaker. A Kalman Filter algorithm is constructed for bounce velocity estimation, and its accuracy is verified through measurements performed with external displacement sensors. The benefit of using adaptive control with Fuzzy-Logic to maintain the optimal performance over a wide range of road inputs is enhanced by the accuracy of Kalman Filter in estimating the controller inputs. A gradient-based optimization algorithm is applied for improving the Fuzzy-Logic controller parameters.
2011-04-12
Technical Paper
2011-01-0430
Aref M. A. Soliman
In this study, LQR control design is presented for the control of a vehicle active suspension system. Seven degrees of freedom, full vehicle model is used. LQR control system is prepared as well as adaptive LQR control system (gain scheduling strategy) to study the effect of each control system using the active suspension on ride performance. The acceleration and dynamic tyre load are evaluated. For the time domain analysis, different road conditions are considered in order to reveal the performance of the two controllers. The simulation results showed that adaptive LQR control system gives a better ride performance compared with LQR control system. Also, the comparison between these control strategies are discussed.
2011-04-12
Journal Article
2011-01-0401
Michele Calabretta, Diego Cacciatore, Phil Carden, Jonathan Plail
Engine efficiency and optimization are key aspects for automotive manufacturers. Lamborghini has particularly focus attention for reduction of time to market building up a synergic approach for new component's development using simulation, Know-how experiences, engine engineering expertise and experimental validation. In particular to reach the best results in the shortest time it is used, in the preliminary stage of development, a massive support of simulation analysis. In the Lamborghini approach analysis and simulation has become key aspects during concept and development of timing drives. This type of activity is used to support the development of better chain timing drives focusing on improving durability, lower friction, less noise and reduced cost in less time than conventional trial and processes. Even during the concept design phase it is useful to use a mathematical model to calculate dynamic forces and motions of a chain drive.
2011-04-12
Technical Paper
2011-01-0062
Bradley Howard, Jingzhou (James) Yang
Digital human modeling and posture prediction can only be used as a design tool if the predicted postures are realistic. To date, the most realistic postures have been realized by simultaneously optimizing human performance measures (HPMs). These HPMs currently consist of joint discomfort, delta potential energy, and visual displacement. However these HPMs only consider the kinematics of human posture. Dynamic aspects of human posture such as external loads and mass of limbs have not yet been considered in conjunction with the current HPMs. This paper gives the formulation for a new human performance measure combination including the use of joint torque to account for the dynamics of human posture. Postures are then predicted using multi-objective optimization (MOO) techniques to optimize the combination of the new HPM and the current. The predicted postures are then compared with the benchmark postures which are those obtained from using the current HPMs only.
2011-04-12
Technical Paper
2011-01-0056
Eric Armengaud, Markus Zoier, Andreas Baumgart, Matthias Biehl, DeJiu Chen, Gerhard Griessnig, Christian Hein, Tom Ritter, Ramin Tavakoli Kolagari
Advanced functionalities unthinkable a few decades ago are now being introduced into automotive vehicles through embedded systems for reasons like emission control, vehicle connectivity, safety and cooperative behaviors. As the development often involves stakeholders from different engineering disciplines and organizations, the complexity due to shared requirements, interdependencies of data, functions, and resources, as well as tight constraints in regards to timing, safety, and resource efficiency makes the system integration, quality control and assurance, reuse and change management increasingly more difficult. This calls for a more rigorous approach to the development of automotive embedded systems and components.
2011-04-12
Technical Paper
2011-01-0541
Mahmoud Yousef Ghannam, Todd Clark, Yeruva Reddy, Jinkoo Lee
This work presents a study of crash energy and severity in frontal offset Vehicle-To-Vehicle (VTV) crash tests. The crash energy is analyzed based on analytical formulations and empirical data. Also, the crash severity of different VTV tests is analyzed and compared with the corresponding full frontal rigid barrier test data. In this investigation, the Barrier Equivalent Velocity (BEV) concept is used to calculate the initial impact velocity of frontal offset VTV test modes such that the offset VTV tests are equivalent to full frontal impact tests in terms of crash severity. Linear spring-mass model and collinear impact assumptions are used to develop the mathematical formulation. A scale factor is introduced to account for these assumptions and the calculated initial velocity is adjusted by this scale factor. It is demonstrated that the energies due to lateral and rotational velocity components are very small in the analyzed frontal VTV tests.
2014-01-15
Journal Article
2013-01-9091
Dongfang Jiang
To get a sequence retainable rainflow cycle counting algorithm for fatigue analysis, an alternate equivalent explanation to rainflow cycle counting is introduced, based on which an iterative rainflow counting algorithm is proposed. The algorithm decomposes any given load-time history with more than one crest into three sub-histories by two troughs; each sub-history with more than one crest is iteratively decomposed into three shorter sub-histories, till each sub-history obtained contains only one single or no crest. Every sub-history that contains a single crest corresponds to a local closed (full) cycle. The mean load and alternate load component of the local cycle are calculated in parallel with the iterative procedure.
2013-11-11
Technical Paper
2013-22-0010
Erik G. Takhounts, Matthew J. Craig, Kevin Moorhouse, Joe McFadden, Vikas Hasija
Rotational motion of the head as a mechanism for brain injury was proposed back in the 1940s. Since then a multitude of research studies by various institutions were conducted to confirm/reject this hypothesis. Most of the studies were conducted on animals and concluded that rotational kinematics experienced by the animal's head may cause axonal deformations large enough to induce their functional deficit. Other studies utilized physical and mathematical models of human and animal heads to derive brain injury criteria based on deformation/pressure histories computed from their models.
2013-04-08
Technical Paper
2013-01-0472
Chad Hovey, Elizabeth Raphael, Henry Xu
In 2008, Hovey et al. [1] published a mathematical analysis that, for the first time, incorporated yaw data into the trajectory analysis, yielding occupant ejection results that are three-dimensional. We extend on that work to investigate the ability of the mathematical model to predict outcomes of the Ford Expedition dolly rollover test, details of which have been published in Carter et al. [2], Exponent [3], and Luepke et al. [4]. This research validates our occupant trajectory model with the Expedition dolly rollover experimental test data. Previous research had modeled the Expedition rollover test as a two-dimensional, straight-line, roll-only configuration, assuming yaw effects were negligible [17]. We incorporated the longitudinal and lateral components of the vehicle trajectory, eliminating the straight-line limitation. Moreover, we included yaw in addition to roll. Both enhancements resulted in a higher fidelity occupant ejection description.
2004-03-08
Technical Paper
2004-01-0145
Michael J. Anderson
The advance in emission control technologies towards Ultra Thin Wall (UTW) substrates has presented packaging challenges. With respect to mounting mats, there are two main problems with the traditional intumescent mats. First, intumescent mats typically generate too much pressure during assembly over their normal mounting range for the promised substrate strength; this can lead to broken substrates during assembly. Second, large pressure spikes occur in heated intumescent mats that could cause broken substrates in the field. As a result, non-intumescent mats are being used to alleviate the two main problems that occur with intumescent mats. A third alternative, a composite or “hybrid” mat, may offer a higher level of performance at lower cost compared to the non-intumescent mat solutions. The hybrid mats referred to in this paper consist of a layer of intumescent mat and a layer of non-intumescent mat.
2004-03-08
Technical Paper
2004-01-0152
Kenneth W. Aniolek
This paper describes efforts to use computational fluid dynamics (CFD) to provide some general insights on how wall-based protuberances affect the flow and thermal fields in substrates exposed to typical diesel engine exhaust conditions. The channel geometries examined included both square and round bumps as well as an extreme tortuous path design. Three different 2d CFD laminar-flow analyses were performed: (1) a transient fluid analysis to identify the existence of any vortex shedding in the vicinity of the bumps, (2) a steady-state fluid analysis to examine the velocity and pressure fields as well as momentum transport characteristics, and (3) a thermal analysis to examine the heat transport characteristics. The model predicts no vortex shedding behind the bumps for the conditions and geometries examined, confirming the validity of a steady state approach and eliminating this possible transport mechanism.
2004-03-08
Technical Paper
2004-01-0155
Andrew P.E. York, Timothy C. Watling, Julian P. Cox, Isabel Z. Jones, Andrew P. Walker, Philip G. Blakeman, Thomas Ilkenhans, Ronny Allansson, Mats Lavenius
A 1-D numerical model describing the ammonia selective catalytic reduction (SCR) de-NOx process has been developed based on data measured on a laboratory microreactor for a vanadia-titania washcoated catalyst system. Kinetics for various NH3-NOx reactions were investigated, as well as those for ammonia, CO and hydrocarbon oxidation. The model has been successfully validated against engine bench measurements, over light-off and ESC tests, under a wide range of conditions, e.g. flow rate, temperature, NO2/NO ratio, and ammonia injection rate. A very good agreement between the experimental data and the model has been achieved. The model has now been used to predict the effect of NO2/NO ratio on NOx conversion, and the effect of different ammonia injection rates on the efficiency of the SCR process.
2004-03-08
Technical Paper
2004-01-0159
T. Mizutani, Y. Watanabe, K. Yuuki, S. Hashimoto, T. Hamanaka, J. Kawashima
The Diesel Particulate Filter (DPF) system has been developed as one of key technologies to comply with tight diesel PM emission regulations. For the DPF control system, it is necessary to maintain temperature inside the DPF below the allowable service temperature, especially during soot regeneration to prevent catalyst deterioration and cracks. Therefore, the evaluation of soot regeneration is one of the key development items for the DPF system. On the other hand, regeneration evaluation requires a lot of time and cost since many different regeneration conditions should be investigated in order to simulate actual driving. The simulation tool to predict soot regeneration behavior is a powerful tool to accelerate the development of DPF design and safe regeneration control strategies. This paper describes the soot regeneration model applied to fuel additive and catalyzed types, and shows good correlation with measured data.
2004-03-08
Technical Paper
2004-01-0158
Gerd Gaiser, Patrick Mucha
Published investigations on the calculation of pressure drop of diesel particulate filters consider the contribution of substrate, soot, channel flow and inertial effects at the inlet and outlet of the channels. The model presented in this work considers further contributions as the oil ash and additive ash and their effects on the DPF pressure drop. It is shown that different types of ash deposit which are caused by different driving cycles and different regeneration modes, will result in a significantly different pressure drop even at the same total amount of ash. It will be shown that in the case without soot load the ash deposit at the wall will result in a higher pressure drop than the same amount of ash being deposited at the rear end of the channels. It is also shown that at a higher soot load this behaviour will be inverted. In addition this work considers a variable permeability of the soot layer varying with the soot load of the filter.
2004-03-08
Technical Paper
2004-01-0182
G. Gottstein, M. Crumbach, M. Goerdeler, L. Neumann, R. Kopp
We report on a novel approach for through-process modeling of anisotropy development during AA5182 sheet production from hot rolling through terminal annealing. For this a thermomechanical process model was coupled to physics based microstructure models for deformation texture (GIA), work hardening (3IVM), and recrystallization texture (StaRT). The model overpredicts the Cube texture during hot rolling but properly predicts the terminal texture after multiple cold rolling with intermediate annealing. This approach can be extended to forming of automative sheet or integrated in crash simulations.
2004-03-08
Technical Paper
2004-01-0179
Shoji Muramatsu, Yuji Otsuka, Hiroshi Takenaga, Yoshiki Kobayashi, Tatsuhiko Monji
A new automotive vision platform has been developed for practical applications. The vision platform simultaneously realizes high-performance computing power and reliability for automotive use by using a newly developed dedicated image processor. The developed processor has specialized and novel hardware allowing it to process a large amount of image data at high speed under a moderate clock frequency. The vision platform has enough capability to process multiple applications at the same time. In this paper, we describe the unified memory architecture in the vision platform. We introduce specific functional units for various applications such as the edge analysis unit. We report results from experiments with a real-time on-board lane recognition system.
2004-03-08
Technical Paper
2004-01-0190
Mauro Velardocchia, Aldo Sorniotti
The paper presents a failsafe strategy conceived for a Vehicle Dynamics Control (VDC) system developed by the Vehicle Dynamics Research Team of Politecnico di Torino. The main equations used by the failsafe algorithm are presented, especially those devoted to estimate steering wheel angle, body yaw rate and lateral acceleration, each of them fundamental to correctly actuate the VDC. The estimation is based on redundancy; each formula is considered according to a weight depending on the kind of maneuver. A new recovery algorithm is presented, which does not deactivate VDC after a sensor fault, but substitutes the sensor signal with the virtually estimated value. The results obtained through simulation are satisfactory. First experimental tests carried out on a ABS/VDC test bench of the Vehicle Dynamics Research Team of Politecnico di Torino confirmed the simulation results.
2004-03-08
Technical Paper
2004-01-0185
Eu-Gene Ng, Mohamed A. Elbestawi, Mihaela Dumitrescu
Advanced manufacturing technology of high silicon aluminium alloys is one of the manufacturing processes in need of new developments to obtain the required improvements for the new generation of vehicles. During ultra high speed machining of aluminium alloys, the optimum machining parameters and tool geometry are controlled by the finished machined workpiece/part surface integrity, burr formation, and part distortion. For the research objectives presented in this paper a dual approach was applied, covering both experimental and theoretical (modeling) work. High speed machining, above 5000 m/min, has been used. From experimental analysis, the most important elements regarding tool life and wear mechanisms are workpiece material microstructure and inhomogenities, non-metallic inclusions, and silicon content.
2004-03-08
Technical Paper
2004-01-0576
Zhang Han, Zhu Yuan, Tian Guangyu, Chen Quanshi, Chen Yaobin
This paper presents a preliminary design and analysis of an optimal energy management and control system for a power-split hybrid electric vehicle (HEV) using hybrid dynamical control system theory and design tools. The hybrid dynamical system theory is applied to formulate HEV powertrain dynamical system in which the interactions of discrete and continuous dynamics are involved. The Sequential Quadratic Programming (SQP) method is applied to optimize power distribution. An improved dynamic programming method is employed to determine the optimal power distribution and the vehicle operating mode transitions.
2004-03-08
Technical Paper
2004-01-0343
Peter J. Schubert, David Nichols, Edward J. Wallner, Henry Kong, Jan K. Schiffmann
Rollover sensing and discrimination generally requires an algorithm that monitors vehicle motion and anticipates conditions that will lead to a rollover. In general, a deploy command is required in a time frame such that safety measures can be activated early enough to protect the occupants. A rollover discrimination system will typically include internal motion sensors, vehicle signals from other on-board sensors, and a microprocessor to execute the deployment algorithm. A supplemental signal path is used to arm the system, making it less susceptible to single point component failures. In this chapter we explore basic concepts of rollover sensors and system mechanization, rollover discrimination algorithms, and arming methodology. A simulation environment that models the performance of the system across part tolerance, temperature extremes and component age is used to estimate the scope of expected discrimination performance in the field.
2004-03-08
Technical Paper
2004-01-0360
Thierry Rolina
Software content is undoubtedly increasing in vehicles with more and more functionality being implemented as real-time embedded features. This paper reviews the traditional approach to implementing such features, discusses the challenges that approach poses and describes a better method to overcome them. We will explore the components of a “building blocks” approach, which will constitute the basis of a process for future real-time automotive embedded software development.
2004-03-08
Technical Paper
2004-01-0351
Burak A. Gecim
Efficiency of a toroidal traction drive is measured at different torques, speeds, speed ratios, and temperatures, with an emphasis on the effect of the design traction coefficient on variator efficiency. This is accomplished by independently controlling the trunnion and the clamp pressures representing the variator torque and the clamp load, respectively. Also measured is the effect of roller conformity on variator efficiency. Furthermore, a low-speed and high-temperature test is conducted to observe a potential change in the effective coefficient of traction due to a transition in the lubrication mode. It is shown that, by optimum clamping (without gross slip) the variator efficiency can be increased by 1- to 2-percentage point over the efficiencies measured with nominal clamp loads. Also verified is the rapid decrease in variator efficiency with over clamping above the nominal clamp loads. All test results compared well with model predictions.
2004-03-08
Technical Paper
2004-01-0378
Jian Pang, Rao Dukkipati, Gang Sheng
The paper presents a procedure for nonlinear model identification of automotive seat cushion structure. In this paper, two nonlinear models are presented. Tests show that the automotive seat cushion structure is a nonlinear system. The transfer functions obtained from the test data between the seat butt and the seat track show that the magnitude and frequency shift will be smaller as the input is increased. The models predict the transfer functions having the same trend as the results from the tests. The models are quite useful for the analysis other car structures and also provide guidance in the design of seat cushions.
2004-03-08
Technical Paper
2004-01-0379
Richard D. Widdle, Anil K. Bajaj, Patricia Davies
Polyurethane foam is often a major constituent of automotive seating, and exhibits highly nonlinear behavior under normal operating conditions. Efficient design requires an understanding, as well a good model, of the foam behavior. The work presented here is an attempt to link continuum and microstructural approaches to modeling foamed materials and take advantage of the utility in each. The outcome will ultimately be the ability to generate a foam superelement that is sensitive to microstructural properties but does not require the computational complexity of a microstructural finite element model. This will facilitate the iterative design of seating for comfort and other dynamic considerations. To this end, an Ogden-type continuum model for compressible rubber-like solids, is fitted to the results of numerous simulated compression tests conducted on finite element models of two-dimensional foam.
2004-03-08
Technical Paper
2004-01-0372
Jian Pang, Rao Dukkipati, Gang Sheng
In this paper, a nonlinear dynamic model for automotive cushion-human body combined structure is developed based on a nonlinear seat cushion model and a linear ISO human body model. Automotive seat cushions have shown to exhibit nonlinear characteristics. The nonlinear seat cushion model includes nonlinear stiffness and nonlinear damping terms. This model is verified by a series of tests conducted on sports car and luxury car seats. The transfer functions from the tests for human body sitting on an automotive seat changes with the vibration platform input magnitudes. This indicates that the combined structure possesses nonlinear characteristics. The nonlinear model is validated by the transfer functions from the test. The paper discusses the influence of the parameters of the nonlinear structure on the design of seat and assessment of human body comfort.
2004-03-08
Technical Paper
2004-01-0422
Philippe Moulin, Gilles Corde, Michel Castagné, Grégory Rousseau
On diesel engines, a discrepancy between the air fuel ratio (AFR) of the cylinders can lead to a decrease of full load performances, an increase of pollutant and noise emissions and has an effect on the aftertreatment efficiency. A cylinder individual AFR estimator has been developed using Kalman filter techniques. This estimator is based on a physical model of the exhaust, and intended to be implemented in an engine management system. The time delay of the exhaust system, including the sensor, can be identified online. When applied on testbed acquisitions, the estimator gives good results over the whole operating range of the engine.
2004-03-08
Technical Paper
2004-01-0426
Han Qiang, Yang Fuyuan, Zhou Ming, Ouyang Minggao
The large amount of controllable fuel injection parameters of Diesel engine equipped with high pressure common-rail fuel injection system makes the control of combustion more flexible, and also makes the workload of calibration and optimization much heavier. For higher efficiency, model-based approaches are presented and researched. This contribution presents a new method for modeling which is constituted by Neural Network and Adaptive Network-based Fussy Inference System (ANFIS). The experiment is carried out on a 6-cylinder common rail diesel engine. The analysis and experiment show that effective modeling can be achieved using this method.
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