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Viewing 1 to 30 of 504
2011-04-12
Technical Paper
2011-01-0090
Wei Liu, Wenku Shi Sr
In this paper, a Magneto-Rheological (MR) fluid semi-active suspension system was tested on a commercial vehicle, a domestic light bus, to determine the performance improvements compared to passive suspensions. MR fluid is a material that responds to an applied magnetic field with a significant change in its rheological behavior. When the magnetic field is applied, the properties of such a fluid can change from a free-flowing, low viscosity fluid to a near solid, and this change in properties takes place in a few milliseconds and is fully reversible. A quarter suspension test rig was built out to test the nonlinear performance of MR damper. Based on a large number of experimental data, a phenomenological model of MR damper based on the Bouc-Wen hysteresis model was adopted to predict both the force-displacement behavior and the complex nonlinear force-velocity response.
2013-04-08
Technical Paper
2013-01-1354
Wenguang Wu, Zhengqi Gu
Electric wheel dump trucks are mainly used in open pit mines, where the working environment is very harsh and the driver's continuous working time is extremely long, therefore, the ride comfort of the truck is pretty important. This paper evaluates and optimizes the ride comfort, according to ISO2631, and Chinese standard GB/T4970-1996 and Chinese standard QC/T76.8-1993, while the ride comfort test had been done in a open pit mine. After the test data was analyzed, the results showed that the ride comfort of this truck needs to be improved and optimized. The multi-body system dynamic model was built in MATLAB/SIMULINK for this dump truck, to simulate the realistic working condition using a D-class road, which was reconstructed according to ISO/DIS8608 and Chinese standard GB7031-86, while the simulation results were in coincidence with the test ones.
2004-03-08
Technical Paper
2004-01-1207
Terry D. Day
SIMON is a new 3-dimensional vehicle dynamic simulation model. The capabilities of the model include non-linear handling maneuvers and collision simulation for one or more vehicles. As a new model, SIMON must be validated by comparison against actual handling and collision experiments. This paper provided that comparison. Included in the validation were lane-change maneuvers, alternate ramp traversals, limit maneuvers with combined braking and steering, vehicle-to-vehicle crash tests and articulated vehicle handling tests. Comparison against other models were included. No metric was provided for handling test comparisons. However, statistical analysis of the collision test results revealed the average path range error was 6.2 to 14.8 percent. The average heading error was -4.7 to 0.7 percent. Delta-V error was -1.6 to 7.5 percent. VEHICLE SIMULATION has many uses in the vehicle design and safety industries.
2004-10-26
Technical Paper
2004-01-2717
Wei Liang, Jure Medanic, Roland Ruhl
Control system design is one of the most critical issues for implementation of intelligent vehicle systems. Wide ranged fundamental research has been undertaken in this area and the safety issues of the fully automated vehicles are clearly recognized. Study of vehicle performance constrains is essential for a good understanding of this problem. This paper discusses safety issues of heavy-duty vehicles under automatic steering control. It focuses on the analysis of the effect of tire force saturation. Vehicle handling characteristics are also analyzed to improve understanding of the truck dynamics and control tasks. A simple differential brake control is formulated to show its effect of on reducing trailer swing.
2004-10-26
Technical Paper
2004-01-2714
Katrin Strandemar, Boris Thorvald
This paper presents the ride diagram, a new way of evaluating and presenting ride comfort Furthermore, a simplified methodology is suggested to test and correlate objective measures of vehicle ride with subjective driver impressions. The ride diagram is calculated from measured cab accelerations resulting from increased levels of excitation. The basic idea is to graphically visualize how ride comfort changes with excitation. Test drivers are then asked to pair the set of tested vehicles with corresponding curves in the ride diagram. This step assures that the selected measure captures how drivers apprehend changes in vehicle ride. The suggested methodology is illustrated on trucks with different cab suspension settings. For a given test track increased vehicle speed is used to increase the excitation level. The trucks are also placed in a road simulator to enable easy variation of both excitation type and level.
2013-10-07
Technical Paper
2013-36-0335
Ana Cristina Soares, Bibiana Quintiliano, Rogério Dias
Evaluation of vehicle performance is one of the most important phases of the new vehicle development. Start Ability and Top Speed are factors that are noticed by users, therefore are very important to the final product. Vehicle performance evaluation has been largely benefited from the use of simulation tools. In fact, MAN Latin America (ML) employs simulation programs to evaluate the performance of its vehicles (trucks and buses) achieving good results. However, those programs are normally “closed codes” which makes difficult the physical comprehension of results. Altogether, this article presents Vehicle Dynamics, a macro developed by ML engineering team. The aim of this macro is the automatic calculation of Start Ability, Grade Ability, Top Speed, among other performance parameters.
2011-09-13
Technical Paper
2011-01-2162
Ross K Brown, Jason Pusey, Muthuvel Murugan, Dy Le
This paper discusses the research conducted by the Army Research Laboratory (ARL) - Vehicle Technology Directorate (VTD) on advanced suspension control. ARL-VTD has conducted research on advanced suspension systems that will reduce the chassis vibration of ground vehicles while maintaining tire contact with the road surface. The purpose of this research is to reduce vibration-induced fatigue to the Warfighter as well as to improve the target aiming precision in theater. The objective of this paper was to explore the performance effectiveness of various formulations of the Generalized Predictive Control algorithm in a simulation environment. Each version of the control algorithm was applied to an identical model subjected to the same disturbance input and compared to a baseline passive suspension system. The control algorithms considered include a Generalized Predictive Controller (GPC) with Implicit Disturbances, GPC with Explicit Disturbances, and GPC with Preview Control.
2011-09-13
Technical Paper
2011-01-2161
Shuang Chen, Changfu Zong, Lei He, Gang Yin
An integrated control strategy for vehicle active suspension system which combines linear quadratic optimum control law with fuzzy control algorithm is designed to improve both ride and handling. The performance of this control strategy is then examined and assessed in an open-loop J-turn driving scenario on a random-rough road by means of computer simulation. Comparisons to a passive suspension system in terms of vehicle sprung mass vertical acceleration, body roll angle and yaw rate is conducted. Simulation results indicate that the integrated control strategy proposed in this paper could effectively enhance vehicle ride comfort meanwhile benefit handling quality and driving safety.
2011-09-13
Technical Paper
2011-01-2145
Jin Huang, Qingmin Huang, Aiguo Cheng
Uncertainties present a large concern in actual vehicle motion and have a large effect on vehicle system control. We attempt a new robust control design approach for braking/driving force distribution and active front steering of vehicle system with uncertain parameters. The braking/driving force distribution control is equivalently studied as the integral direct yaw moment control. Then the control design is carried out by using a state-space vehicle model with embedded fuzzy uncertainties. By taking the compensated front wheel steering angle and the direct yaw moment as the control inputs, a feedback control that aims to compensate the system uncertainty is proposed. In a quite different angle, we employ fuzzy descriptions of the uncertain parameters. The controlled system performance is deterministic, and the control is not if-then rules-based. Fuzzy descriptions of the uncertain parameters are used to find an optimal control gain.
2011-04-12
Technical Paper
2011-01-0979
Hocine Imine, Omar Khemoudj
The aim of the presented work is to estimate the vertical forces of heavy vehicle and identify the unknown dynamic parameters using sliding mode observers approach. This observation needs a good knowledge of some dynamic parameters such as damping coefficient, spring stiffness…etc. We propose in this paper, to identify some of these parameters which are, in practice very difficult to obtain and to measure. This identification will improve the quality of vertical forces estimation. Some experimental results are presented in order to show the quality of the estimation and identification. These estimation results are then compared to the measures coming from an instrumented tractor.
1999-12-01
Technical Paper
1999-01-2990
Eraldo Jesus Soares, Daniel Maretti De Carvalho, Hélcio Onusic, Júlio Antônio Barreiro, Luiz Carlos Ferraro
SUMMARY Because of the increasing need to reduce the time of development of new products, or even to evaluate the reliability of products, one has been noticing a trend to rationalize field tests through essays in ever more representative test benches, within a shorter period of time at a lower cost. In the automotive industry, the trend is to increase the reliability of tests in benches. The quantity of simulated parameters is increasing, what demands an ever increasing survey of data based on measurements of signals of deformation of leaves of spring leaf and courses of suspension in experimental vehicles.
2000-03-06
Technical Paper
2000-01-0036
Kazunari Nakahara, Katsutoshi Ohta
A cylindrical hydraulic engine mount with simple construction has been developed which has a sub chamber formed without diaphragm by utilizing air compressibility. An analysis model of the mount is presented to predict the non-linear dynamic characteristics in consideration of the effect of excitation amplitude on the dynamic stiffness and loss factor. The calculated dynamic characteristics are in good agreement with experimental results. By using the analysis model, the effect of the volume and pressure of air on the dynamic characteristics is clarified. On-vehicle test on a chassis dynamometer shows that the newly developed hydraulic engine mount has same effect on ride comfort improvement as a conventional hydraulic mount.
1999-11-15
Technical Paper
1999-01-3781
Ragnar Ledesma, Shan Shih
The uniqueness and challenge of heavy and medium duty vehicle manufacturing is that the vehicle&s subsystems and major components are procured from different suppliers. As a consequence, engineering task coordination for total vehicle performance optimization is required even if the intended design modification is only on one component. In the case of suspension design, related subsystems such as the drive axle, driveline, brake system, steering system, and engine mounts should all be included for review. The related potential problems for study fall into three categories, namely: function, durability, and NVH. The effective approach in addressing all these issues early in the design stage is through computer modeling and dynamic system simulation of the suspension system and related subsystems.
1999-11-15
Technical Paper
1999-01-3707
Mark A. Bennett, William P. Amato
The accuracy of existing rotational wheel dynamics models has been found to be insufficient for heavy vehicle Antilock Braking System (ABS) and Electropneumatic Braking System (EBS) simulation, specifically when wheelspeeds are at or near zero but the vehicle speed is not. Control strategies specific to ABS and EBS, the low frequency response of pneumatic actuation, and the practice of using fewer modulators than braked wheels require that a vehicle model be able to handle lockedwheel scenarios accurately. Commercially available models have been found unsatisfactory in this regard, and technical literature has not been found to address this issue.
2010-10-05
Technical Paper
2010-01-1922
Yen-Chi Chang, Tseng-Ti Fu
Virtual prototyping has been widely used in the industry and academy as a system performance prediction tool before production. Particularly for the analysis of vehicle ride comfort, the quarter car model is popular since it requires only the essential and least amount of input data. However, the assumption of point contact between the tire and road may sometimes be misleading, especially in rough road applications or low pressure tires for all terrain vehicles (ATV). To have a realistic prediction at the early design stage when little information is available, the quarter car model is modified in this research by allowing the tire to leave off the ground and considering variable tire patch contact. These features are important when designing ATVs used in versatile environments and with low pressure tires. Inclination of distributed tire springs and constant division road profile are implemented to facilitate fidelity and efficiency in simulation.
2010-10-05
Technical Paper
2010-01-1923
Takayuki Koizumi, Tatsuya Yoshida, Hiroaki Andou, Nobutaka Tsujiuchi
A high performance digging algorithm for a hydraulic excavator has not been established because the relationship between digging parameters and digging performance is complex. An examination process for a high-performance digging algorithm is proposed. In this paper, the digging efficiency is defined as the soil volume derived by the applied energy to drive the bucket in order to evaluate digging performance. The digging algorithm, which we study for high digging efficiency, decreases the reaction force to the bucket from the soil by moving the bucket upward when the reaction force exceeds a threshold during digging. Digging tests are performed with a miniature test device and a simulation model by two-dimensional distinct element methods (2D-DEM). The device and the simulation assess the effectiveness of the digging algorithm. It is quantitatively shown that the digging performance obtained by the feedback digging system is improved to prevent growing of reaction force.
2005-04-11
Technical Paper
2005-01-0405
Namir J. Zara
The four wheel steer system better known as the Quadra Steer system (QS4) is a system that provides steering control of the rear wheel of long based pickups and large sport utilities. Analysis was utilized to develop Rear/Front (R/F) steering algorithm with the vehicle in it's normal mode which is characterized as vehicle at curb + 2 passengers or GVW/RGAWR on dry surface. Analysis utilized BZ3 control response simulation model to conduct this study. This dynamic model was used to evaluate key vehicle handling parameters to validate and optimize the algorithm.
2004-10-26
Technical Paper
2004-01-2624
Manuel J. Fabela-Gallegos, David Vazquez-Vega
In this paper, the importance of determining the lateral acceleration to characterize terrestrial vehicle behavior and its performance is addressed. Also, the technical difficulties to measure such acceleration and its dependency with vehicle roll angle are described. In the analysis of the motion of the vehicle's center of gravity (CG) and regarding to transversal acceleration components, the acceleration of gravity is taken into account to determine the roll angle, the lateral acceleration and the behavior of vertical acceleration component. As a result, and based upon the principles of operation of accelerometers, a scheme for a simple instrumentation to estimate the roll angle and lateral acceleration in an experimental assessment, is suggested as well.
2016-04-05
Technical Paper
2016-01-1437
Giorgio Previati, Massimiliano Gobbi, Giampiero Mastinu
Abstract The paper is focused on both the subjective and the objective ride comfort evaluation of farm tractors. The experimental measurement of the relevant accelerations occurring at the tractor body, at the cabin and at the seat was performed on a number of different farm tractors. A subjective rating of the ride comfort level was performed by considering five different drivers. The comfort index was computed according with ISO 2631 and other standards. The acceleration of the seated subject was computed by means of a proper mechanical model of a farm tractor and derived at different positions on the subject body. It turned out that the acceleration of the lower torso was particularly relevant for establishing a matching between the subjective perception and the objective measurement and computation. A number of indices have been derived from the measured data which are able to correlate the subjective driver feeling with the measured accelerations.
2016-09-27
Technical Paper
2016-01-8038
Yunbo Hou, Yang Chen, Mehdi Ahmadian
Abstract This paper studies the effect of different longitudinal load conditions, roundabout cross-sectional geometry, and different semi-truck pneumatic suspension systems on roll stability in roundabouts, which have become more and more popular in urban settings. Roundabouts are commonly designed in their size and form to accommodate articulated heavy vehicles (AHVs) by evaluating such affects as off-tracking. However, the effect of the roadway geometry in roundabouts on the roll dynamics of semi-tractors and trailers are equally important, along with their entry and exit configuration. , Because the effect of the roundabout on the dynamics of trucks is further removed from the immediate issues considered by roadway planner, at times they are not given as much consideration as other roadway design factors.
2016-09-27
Technical Paper
2016-01-8037
Nan Xu, Konghui Guo, Yiyang Yang
Abstract The tire mechanics characteristics are essential for analysis and control of vehicle dynamics. Basically, the effects of sideslip, longitudinal slip, camber angle and vertical load are able to be represented accurately by current existing tire models. However, the research of velocity effects for tire forces and moments are still insufficient. Some experiments have demonstrated that the tire properties actually vary with the traveling velocity especially when the force and moment are nearly saturated. This paper develops an enhanced brush tire model and the UniTire semi-physical model for tire forces and moments under different traveling velocities for raising need of advanced tire model. The primary effects of velocity on tire performances are the rubber friction distribution characteristics at the tire-road interface.
2016-09-27
Technical Paper
2016-01-8048
Akihiro Nakamura, Satoru Kaneko, Toshikazu Minoshima, Naokazu Oda
Abstract A method for suppressing pantograph bounce of trolley-assisted mining dump trucks is proposed and verified. Pantograph bounce is a phenomenon in which a pantograph loses contact with an overhead trolley line. Electrical components installed in the dump truck may be damaged by arcing when pantograph bounce occurs. In conventional countermeasures, road roughness is reduced by maintenance of the road surface and pantograph contact pressure is increased by additional actuators; however, pantograph bounce recurs when road and dump-truck conditions change. It is therefore important to prevent pantograph bounce even in the cases of no road maintenance and no pantograph modification. The proposed suppression method consists of two key functions: predicting pantograph bounce and preventing the front end of vehicle from sinking on the basis of the predicted pantograph bounce.
2016-09-27
Technical Paper
2016-01-8050
Chihua Lu, Wenxin Yang, Hao Zheng, Jingqiang Liang, Guang Fu
Abstract In this paper, we propose a method of dynamics simulation and analysis based on superelement modeling to increase the efficiency of dynamics simulation for vehicle body structure. Using this method, a certain multi-purpose vehicle (MPV) body structure was divided into several subsystems, and the modal parameters and frequency response functions of which were obtained through superelement condensation, residual structure solution, and superelement data restoration. The study shows that compared to the traditional modeling method, the computational time for vehicle body modal analysis can be reduced by 6.9% without reducing accuracy; for the purpose of structural optimization, the computational time can be reduced by 87.7% for frequency response analyses of optimizations; consistency between simulation and testing can be achieved on peak frequency points and general trends for the vibration frequency responses of interior front row floors under accelerating conditions.
2016-09-27
Technical Paper
2016-01-8028
Chao Yang, Nan Xu, Konghui Guo
Abstract This paper focuses on the modeling process of incorporating inflation pressure into the UniTire model for pure cornering. Via observing and manipulating the tire experimental data, the effects of inflation pressure on the tire cornering property are analyzed in detail, including the impacts on cornering stiffness, the peak friction coefficient, the curvature of transition region and the pneumatic trail. And the brief mechanism explanations are also given for some of these impacts. The results show that some effects of inflation pressure are similar to that of vertical load on the non-dimensional tire cornering property, and there are strong interactive effects between the two operating conditions. Therefore, in order to obtain concise expressions, the inflation pressure is incorporated into the UniTire tire model by analogy with the expressions for vertical load, and the interactive effects are also taken into account.
2016-04-05
Journal Article
2016-01-1670
Qian Wang, Beshah Ayalew, Amandeep Singh
Abstract This paper outlines a real-time hierarchical control allocation algorithm for multi-axle land vehicles with independent hub motor wheel drives. At the top level, the driver’s input such as pedal position or steering wheel position are interpreted into desired global state responses based on a reference model. Then, a locally linearized rigid body model is used to design a linear quadratic regulator that generates the desired global control efforts, i.e., the total tire forces and moments required track the desired state responses. At the lower level, an optimal control allocation algorithm coordinates the motor torques in such a manner that the forces generated at tire-road contacts produce the desired global control efforts under some physical constraints of the actuation and the tire/wheel dynamics. The performance of the proposed control system design is verified via simulation analysis of a 3-axle heavy vehicle with independent hub-motor drives.
2017-01-10
Technical Paper
2017-26-0345
Bharat Kushwaha, Sanjay Chaudhuri, Sujatha Chandramohan
Abstract This paper investigates the yaw dynamic behaviour of a seven axle tractor semitrailer combination vehicle developed by VRDE (Vehicle Research & Development). The semitrailer has four steerable axles which follow command steering law i.e. all axles of semitrailer are steered in a particular relation with articulation of tractor. A 4 dof (degree of freedom) linear yaw plane model was developed for this combination vehicle. Yaw response characteristics such as lateral acceleration, yaw rate and articulation angle for step and sine steer is obtained from this model. Effects of speed on the above parameters are also studied to the same steering inputs. Lateral tyre forces due to semitrailer steering at various speeds are estimated to understand its distribution on each axle. Steady state yaw rate and articulation angle gain are obtained to predict the understeer / oversteer behaviour of combination vehicle.
2015-09-29
Technical Paper
2015-01-2842
Hongyu Zheng, Jinghuan Hu, Shenao Ma
Abstract Heavy vehicles have the characteristics of with high center of gravity position, large weight and volume, wheelbase is too narrow relative to the body height and so on, so that they always prone to rollover. In response to the above heavy security problems of heavy vehicle in running process, this paper mainly analyzes roll stability and yaw stability mechanism of heavy vehicles and studies the influence of vehicle parameters on stability by establishing the vehicle dynamics model. At the same time, this paper focuses on heavy vehicles stability control methods based on simulation and differential braking technology. At last, verify the effect of heavy vehicle stability control by computer simulation. The results shows that self-developed stability control algorithm can control vehicle stability effectively, so that the heavy vehicles instability can be avoided, the vehicle driving safety and braking stability are improved.
2014-05-07
Technical Paper
2014-36-0001
Alfred Memmel, Anibal Berberich
Abstract Variable Damping systems for commercial vehicle applications have been in the market for several years now. The systems modify damping according to the actual demand within milliseconds. This reduces vertical accelerations which lead to improved comfort while maintaining vehicle stability and safety at the same time. Driver, cargo and vehicle are better protected. The technical effort for variable damping systems was in the past rather high and affected a limited market penetration. On the other side the used control algorithms did not tap the full potential of the system performance. New concepts, like integration of sensors or concentration on the most relevant axle, in combination with new control algorithms, simplifies the systems architecture and improves the performance. Besides the functional advantages, the system improves vehicle efficiency as it reduces the energy dissipated by the dampers. This energy would have to be generated by the engine.
2015-03-10
Technical Paper
2015-01-0016
Changxin Wang, Wenku Shi, Zan Li, Fuxiang Guo
Abstract This paper presents the study of chassis tuning of a commercial vehicle, which has a rear suspension with dual stage leaf spring assembly and a front suspension with double wishbone torsion bar. To balance the handling and ride performance of the vehicle, it is necessary to tune the key suspension parameters of the chassis including the dual stage stiffness of the leaf spring, the contact load of the leaf spring, the torsional rigidity of the torsion bar, the force curve of the front and rear dampers etc. The chassis tuning process of a physical commercial vehicle was first put forward. In the proposed flowchart, the kinematics and statics of front & rear suspensions were checked at the beginning of the tuning. Then the tire mechanical characteristics were tested by using a plate-type tire tester and the inertial parameters of the vehicle were indirectly measured. The K&C characteristics of front and rear suspensions were also tested and compared with the benchmark vehicle's.
2015-01-14
Technical Paper
2015-26-0181
Mukund Trikande, Sujithkumar Muralidharan, Vinit Jagirdar
Abstract This study is made on a simplified pitch model of an armored fighting vehicle. Jerks and angular acceleration inside the vehicle compartment Affects accurate firing attack and reduced fatigue to the occupants in Vehicle. The Stability Augmentation Technique can enhance the stability and ride comfort of the vehicle platform from road and firing disturbance. The force requirement for stabilizing the platform is calculated from the displacement of vehicle body in terms of pitch angle and Heave displacement with respect to the equilibrium position, the equivalent force at suspension mounting points required to stabilize the platform is calculated using a force transformation technique. The required force is given by an active Damper for stabilization, within the limit of damper capacity.
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