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Viewing 1 to 30 of 9080
2010-04-12
Technical Paper
2010-01-0384
Aref M. A. Soliman
This paper deals with an investigation of the road roughness on the vehicle ride comfort using semi-active suspension system. A mathematical model of quarter vehicle for semi active suspension system is developed to evaluate vehicle ride comfort. The rolling resistance and power losses are also investigated. The power consumed in rolling resistance and power dissipation in suspension for passive and semi-active suspensions are evaluated. The obtained results showed that ride comfort increases as the road roughness is decreased. Comparisons between passive and semi-active suspensions systems in terms of ride performance and power dissipation are also discussed.
2010-04-12
Technical Paper
2010-01-0496
Praveen Halepatali, Christopher Ha, Ronald C. Averill
Faced with competitive environments, pressure to lower development costs and aggressive timelines engineers are not only increasingly adopting numerical simulation techniques but are also embracing design optimization schemes to augment their efforts. These techniques not only provide more understanding of the trade-offs but are also capable of proactively guiding the decision making process. However, design optimization and exploration tools have struggled to find complete acceptance and are typically underutilized in many applications; especially in situations where the algorithms have to compete with existing swift decision making processes. In this paper we demonstrate how the type of setup and algorithmic choice can have an influence and make optimization more lucrative in a new product development atmosphere. We also present some results from a design exploration activity, involving linkage and structural development, of an earth moving machine application.
2011-04-12
Technical Paper
2011-01-0269
Adam Bryant, Joseph Beno, Damon Weeks
Battlefield reconnaissance is an integral part of today's integrated battlefield management system. Current reconnaissance technology typically requires land based vehicle systems to observe while stationary or, at best, significantly limits travel speeds while collecting data. By combining current Canadian Light Armored Vehicle based reconnaissance systems with the Center for Electromechanics (CEM) electronically controlled active Electromechanical Suspension System (EMS), opportunities exist to substantially increase cross-country speeds at which useful reconnaissance data may be collected. This report documents a study performed by The University of Texas Center for Electromechanics with funding from L3-ES to use existing modeling and simulation tools to explore potential benefits provided by EMS for reconnaissance on the move.
2011-04-12
Journal Article
2011-01-0344
Gilsu Choi, Zhuxian Xu, Ming Li, Shiv Gupta, Thomas Jahns, Fred Wang, Neil A. Duffie, Laura Marlino
This paper introduces a promising approach for developing an integrated traction motor drive based on the Integrated Modular Motor Drive (IMMD) concept. The IMMD concept strives to meet aggressive power density and performance targets by modularizing both the machine and power electronics and then integrating them into a single combined machine-plus-drive structure. Physical integration of the power electronics inside the machine makes it highly desirable to increase the power electronics operating temperature including higher power semiconductor junction temperatures and improved device packaging. Recent progress towards implementing the IMMD concept in an integrated traction motor drive is summarized in this paper. Several candidate permanent magnet (PM) machine configurations with different numbers of phases between 3 and 6 are analyzed to compare their performance characteristics and key application features.
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
2011-01-0266
J.Y. Wong
With growing globalization of the economy, to gain a competitive edge in world markets shortening the product development cycle is crucial. Virtual product development is, therefore, being actively pursued in the off-road vehicle industry. To implement this process successfully, the development of comprehensive and realistic computer-aided methods for performance and design evaluation of off-road vehicles is of vital importance. To be useful to the engineer in industry for the development and design of new products, the computer-aided methods should take into account all major vehicle design parameters and pertinent terrain characteristics. They should be based on the understanding of the physical nature and the mechanics of vehicle-terrain interaction. Their capabilities should be substantiated by test data.
2011-04-12
Technical Paper
2011-01-0438
Ahmet Kanbolat, Murathan Soner, Tolga Erdogus, Mustafa Karaagac
The parabolic leaf spring plays a vital role in suspension systems, since it has an effect on ride comfort and vehicle dynamics. Primarily, leaf spring endurance must be ensured. Presently, there are two approaches to designing a leaf spring. In the traditional method, fatigue tests should be repeated for each case, considering different material, geometry and suspension hard points. However, it takes a long time and requires a heavy budget to get the optimized solution. In the contemporary method, a numerical approach is used to obtain the fatigue life and the leaf geometry against the environmental condition on the basis of material properties. This paper presents a more precise method based on non-linear finite element solutions by evaluating the effects of the production parameters, the geometrical tolerances and the variations in the characteristics of the material.
2011-04-12
Journal Article
2011-01-0437
Mina M.S. Kaldas, Roman Henze, Ferit Küçükay
Due to the importance of the fast transportation under every circumstance, the transportation process may require a high speed heavy vehicle from time to time, which may turn the transportation process more unsafe. Due to that fact the truck safety during braking and the ride comfort during long distance travelling with high speeds should be improved. Therefore, the aim of this work is to develop a control system which combines the suspension and braking systems. The control system consists of three controllers; the first one for the active suspension system of the truck body and cab, the second one for the ABS and, the third for the integrated control system between the active suspension system and the ABS. The control strategy is also separated into two strategies.
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
Technical Paper
2011-01-0429
Mathew Kuttolamadom, Joshua Jones, Laine Mears, John Ziegert, Thomas Kurfess
For incorporating titanium components onto a vehicle in place of existing iron/steel components, there is a need for a methodical procedure to ensure successful and efficient integration. This involves a refinement over standard lightweight engineering procedures. In this paper, a suitable procedure is developed for replacing a structural component with titanium and the method realized. Design and manufacturing issues associated with integrating titanium are identified and addressed. The importance of justifying component replacement in terms of life-cycle costs rather than purely by the manufacturing cost alone is also emphasized.
2011-04-12
Technical Paper
2011-01-0453
Horst Salzwedel
The rapid increase of networked electronic control units in airplanes (Line Replaceable Units or Modules, LRUs/LRMs) and automobiles (ECUs) requires to move from CAN buses to higher performance buses. In aircraft the number of LRUs exceeded 100 in 1990 (B777) and is now ≻5000 (A380). Today, the number of ECUs in some automobiles also exceeds 100. Aircraft industry developed solutions based on standard switched Ethernet (AFDX) and standardized ECUs, called Integrated Modular Avionic units (IMA units) and common remote data concentrators (cRDCs) that are now flying in the Airbus A380 and A400M, the Boeing B787, and are being used in the design of future civil and military aircraft. During the last decade, automotive industry has been pursuing the development of specialized FlexRay bus solutions for automotive control and specialized MOST bus solutions for comfort electronics. However, some automotive companies are now also looking at Ethernet-based solutions.
2010-04-12
Technical Paper
2010-01-1146
Andrés E. Rojas Rojas, Haymo Niederkofler, Johann Willberger
Volatile oil prices and increased environmental sensitivity together with political concerns have moved the attention of governments, automobile manufacturers and customers to alternative power trains. From the actual point of view the most promising concepts for future passenger cars are based on the conversion of electrical into mechanical energy. In-wheel motors are an interesting concept towards vehicle electrification that provides also high potentials to improve vehicle dynamics and handling. Nevertheless in-wheel motors increase the unsprung mass worsening vehicle comfort and safety. The paper analyses potentials and limitations of innovative passive concepts as well as of new mechatronic suspension systems in order to assure appropriate levels of vehicle comfort and safety when using in-wheel motors with different torque requirements. To reach the mentioned objective, the weight of synchronous and asynchronous electric motors is computed for different torque requirements.
2010-04-12
Technical Paper
2010-01-1143
Joerg Neubrand, Andreas Lindner, Robert Brandt, Christian Junker
For more than 20 years Mubea strives to develop and produce highly stressed suspension springs and other lightweight automotive steel products. Despite continuous increase of load stress levels of suspension springs it was possible to significantly reduce the weight of suspension springs while increasing robustness. As a successful supplier the company needs to address the continually increasing requirements of the automotive industry for reduced vehicle weight and CO₂ emission through strong efforts in design and process optimization. Targeted now is a weight reduction of another 10% while further enhancing coil spring robustness. In order to achieve these targets Mubea has again optimized the already established High Performance Process (HPP) and has developed a new and innovative method of designing coil springs. To optimize coil spring design customized Finite Element (FE) software was developed and successfully implemented.
2010-04-12
Technical Paper
2010-01-1141
Yong Woo Park, Hyo Seok Kim, Kwangjin Joo, Namil Jeon
The purpose of this paper is to identify and reduce the suspension rattle noise. First, the characteristics of the rattle noise are analyzed experimentally in the time and frequency domain. It was found that the rattle noise and vibration at shock absorber mounting point are strongly correlated. Second, the sensitivity analysis of design parameters is performed using a half car model in ADAMS. The result of the simulation model is verified by comparison with test. Finally, the influence of design parameters for the rattle noise is investigated. The study shows that the shock absorber mounting bushing is the most sensitive parameter to affect the suspension rattle noise. This paper shows how the suspension rattle noise can be improved.
2010-04-12
Technical Paper
2010-01-1140
Shawky Hegazy, Corina Sandu
This paper presents a six degree of freedom full vehicle model simulating the testing of heavy truck suspensions to evaluate the ride comfort and stability using actual characteristics of gas charged single tube shock absorbers. The model is developed using one of the commercial multi-body dynamics software packages, ADAMS. The model incorporates all sources of compliance: stiffness and damping with linear and non-linear characteristics. The front and the rear springs and dampers representing the suspension system were attached between the axles and the vehicle body. The front and the rear axles were attached to a wheel spindle assembly, which in turn was attached to the irregular drum wheel, simulating the road profile irregularities. As a result of the drum rotation, sudden vertical movements were induced in the vehicle suspension, due to the bumps and rebounds, thus simulating the road profile.
2010-04-12
Technical Paper
2010-01-1135
Krishna Prasad Balike, Subhash Rakheja, Ion Stiharu
Automotive suspensions invariably exhibit asymmetric damping properties in compression and rebound, which is partly attributed to asymmetric damping and in-part to the suspension linkage kinematics together with tire lateral compliance. Although automotive suspensions have invariably employed asymmetric damping, the design guidelines and particular rationale for such asymmetry has not been explicitly defined. The influences of damper asymmetry together with the suspension kinematics and tire lateral compliance on the dynamic responses of a vehicle are investigated analytically under bump and pothole excitations, and the results are interpreted in view of potential design guidance. A quarter-car kineto-dynamic model of the road vehicle employing a double wishbone type suspension comprising a strut with linear spring and multiphase asymmetric damper is formulated for the analyses.
2010-04-12
Technical Paper
2010-01-1139
Mike J. Johnston, Rob Rieveley, Jennifer Johrendt, Bruce Minaker
Though the purpose of a vehicle's suspension is multi-faceted and complex, the fundamentals may be simply stated: the suspension exists to provide the occupants with a tolerable ride, while simultaneously ensuring that the tires maintain good contact with the ground. At the root of the familiar ride/handling compromise, is the problem that tuning efforts which improve either grip or handling are generally to the detriment of the other. This study seeks to set forth a clear means for examining the familiar ride/handing compromise, by first exploring the key ideas of these terms, and then by describing the development of content-rich metrics to permit a direct optimization strategy. For simplicity, the optimization problem was examined in a unilateral manner, where heave (vertical; z-axis) behaviour is examined in isolation, though the methods described herein may be extended to pitch and roll behaviour as well.
2010-04-12
Technical Paper
2010-01-1138
Efthimio Duni, Giovanni Toniato, Raffaele Saponaro, Paolo Smeriglio, Vincenzo Puleo
This work describes a numerical methodology based on the Finite Element approach able to simulate the dynamic maneuver of the full vehicle running on fatigue reference roads. The basic idea of present work stays in combining a moderately complex and general finite element tire model with traditional full-vehicle methods, including both implicit and explicit finite element techniques, in order to predict the dynamic response of the car running on the real fatigue reference roads. Some issues related to application of tire finite element model to a long simulation time in an explicit solution have been discussed. The best integration strategy between implicit and explicit solutions, based on pure sequential and/or the combined sequential and co-simulation mode is discussed. The real fatigue load is digitalized and implemented as a rigid body in the explicit code.
2010-04-12
Technical Paper
2010-01-1137
Bhaskar Chaturvedi, Deepak Rana, Mugundaram Ravindran
In a highly competitive market, one of the major challenges for an automobile designer is to lower the product cost while improving the performance. Therefore, from the vehicle comfort point of view, achieving a good ride, handling and NVH performance, while satisfying the low cost and low weight target needs attention from the concept stage of the development cycle. To achieve this balance, it is important to optimize the static and dynamic stiffness of the vehicle body. This paper focuses on the effect of vehicle body stiffness on the ride, handling and NVH parameters. It also addresses the relation between static and dynamic stiffness of the vehicle. The correlation of the stiffness values with the ride, handling and NVH performance is also studied through various experiments on the actual vehicle
2010-04-12
Technical Paper
2010-01-1136
Seung-hoon Woo, Chang Su Kim, Choong kim
Various deformation shapes of the vehicle body were investigated for the purpose to establish vehicle body's performance criteria which correlates well to handling performance and ride comfort. Using CAE tool, the dynamic behavior of a structure by its modal parameter can be described instead of by its nodes and elements. Each modal characteristic in a dynamic system is reduced by its modal stiffness, its modal mass and its damping parameter in the model. This technology offers not only computational efficiency but also parametric model enabling easy what-if simulation. This reduced model can be obtained by modal test as well as simulation of full FE model. It was also investigated that which mode is sensitive to ride or handling performance using the parameterized model. The body stiffness of the brand new 2010 SONATA was improved on reference to the sensitivity analysis. The ride and handling performance of the 2010 SONATA were verified by computer simulation and vehicle field test
2010-10-10
Technical Paper
2010-01-1680
Joseph Hartley, Andrew Day, Ioan Campean, Rod G McLellan, John Richmond
Tata Motors Limited plan to launch a range of full electric vehicles (FEVs) to the European market. Regenerative braking is advantageous in maximising range between recharging, but presents challenges of acceptable performance, weight, cost and the ‘blending’ of regenerative braking with friction braking. Control systems for regenerative braking have been developed by manufacturers to enable recuperation of kinetic energy which would otherwise be converted to heat and wasted through the use of friction brakes. This paper presents the approach taken by Tata Motors Ltd. to optimise the design and operation of a regenerative braking system to maximise range and energy efficiency. The Tata Ace EV is a Class N1 light commercial FEV with drive to the rear wheels only. This presents the challenge of harvesting energy from the axle which contributes a varying amount of the vehicle braking effort depending upon load.
2010-10-10
Technical Paper
2010-01-1682
Michael Herbert Putz
Scientists at the Austrian Institute of Technology (AIT), formerly Austrian Research Center, focused on investigating electro mechanical brakes (EMB) for automobiles. Research showed that EMBs can address brake distribution with regenerative and friction braking ("blending") at hybrid and electric cars due to the ability of the EMBs to be actuated as required (and do not automatically produce brake force at pedal activation). The target was to develop an EMB with low actuation force and energy that is simple and reliable, rolls back to disengage when power is off and acts as a parking brake. Several solutions were considered (with and without self-amplification). A pivotal mechanism with very high transmission ratio using eccentricity emerged as a favorable solution. Vienna Engineering (VE) took over and assumed the research during 2010. VE revealed that non-linear behavior facilitated low actuation forces at high braking torque and can use a controlled amount of self-amplification.
2010-10-10
Technical Paper
2010-01-1705
Matt Kero, Andrew Halonen
The objective of this paper is to highlight the design, analysis, testing, and application engineering performed to develop a lightweight brake drum made of aluminum metal matrix composite (MMC). Current cast iron brake drums are “design-limited” in the sense that new designs do not significantly change performance and they offer minimal weights savings. This paper will begin with the design of the drum with respect to SAE requirements, and then show how the drum was optimized using finite element analysis (FEA). FEA was used to predict maximum drum temperatures and stress levels reached during various braking events. There were a number of design iterations that led to the current design that has been extensively tested on the dynamometer and on a vehicle. In addition to test performance, the casting and infiltration challenges led to significant design changes.
2010-10-10
Technical Paper
2010-01-1703
Russell Creed, Andrew Creed, John P. Deconti
It is well known that heat generated during vehicle braking affects wear and stopping distances. To improve these conditions, supplemental retarders, such as exhaust brakes on diesel powered trucks and electromagnetic retarders have been used for years. Several of the diesel engines (below 7 Liters) are no longer designed to allow the use of exhaust brakes, and gas powered vehicles do not have that option either. Other options such as electromagnetic retarders are heavy, draw excessive amounts of current, and are a costly installation. To fill the void left by the elimination of exhaust brakes from some of these vehicles, and to provide an option that improves upon the undesirable aspects of electromagnetic retarders, a new technology; Liquid Cooled Disc Brakes, has been developed and designed into a product that fits on most popular truck chassis in the Class 2 - 4 range.
2010-10-10
Technical Paper
2010-01-1704
Florian Fuellgrabe, Hermann Winner, Ingo Hoffmann
Cast iron/aluminum composite brake disks are increasingly being employed, as they offer improved fuel efficiency and a lower unsprung mass. The achievable mass reduction and the product costs are determined by the joining concept. This paper presents two novel lightweight composite brake disks, which are produced using two different joining methods. The connection of the first lightweight brake disk under investigation in this study is implemented by friction welding. The second brake disk uses the forming processes spinning and flow forming. The requirements regarding the design of the concepts are presented in the course of this paper. Both lightweight concepts have been validated in standardized tests on a test bench. The results of the experimental investigation are discussed regarding to the key aspects of mass reduction, thermal and mechanical behavior and production.
2010-10-10
Technical Paper
2010-01-1708
Jae Seung Cheon
A dry Brake-By-Wire (BBW) system is one in which the existing hydraulic system is replaced by motor driven electro-mechanical calipers. Although it has yet to be introduced into series production, the attractive benefits of BBW have kept it in the mainstream of brake research for a number of years. In the current investigation, the BBW system is configured with electric wedge brakes in the front axle where high braking forces are required, while conventional electro-mechanical brakes are used in the rear axles. This paper will examine the feasibility of the current BBW system configuration through lab and vehicle performance tests including ABS (anti-lock braking system).
2010-10-10
Technical Paper
2010-01-1707
Yan-Sin Liao, Chien-Tai Huang, Chien-Tzu Chen, Shou-Yi Cheng, Bo-Ruei Chen, Fu-Yen Huang
A new design of integrated Electric Parking Brake system, called iEPB and integrated in the brake caliper, is introduced in this paper. It consists of an electrically operated brake unit and a hydraulically pressed unit independently, and uses a special self-locking mechanism instead of a screw device to increase the efficiency and the working speed. With all conventional EPB system's advantages, it also provides a stronger brake performance and a faster reaction time. In this paper, we describe the working principle of this new design at first, and then introduce the arrangement of the testing system, followed by a discussion of experimental data. The testing results prove the feasibility of this design. The conclusion paragraph summarizes the key points about the design of the iEPB system.
2010-10-10
Technical Paper
2010-01-1713
Vladimir Sergienko, Mikhail Tseluev, Sergey Bukharov
The work presents the results of numerical investigations of the effect of the load and velocity parameters of a mining truck moving over a long descending grade upon thermal conditions of the multidisc oil-cooled brake (MDOB) operation. The initial boundary-value problem for the heat transfer in the MDOB friction pair under frictional heating has been formulated and solved by the finite-element method. The computations performed for the friction pair of high-carbon steel against frictional composite material based on polymer binders. The effect of the load-velocity operation parameters on the thermal conditions of the mining truck MDOB was studied by way of a multifactor numerical experiment using a mathematical model of heat transfer in the MDOB friction pair.
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