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Viewing 61 to 90 of 10521
2016-04-05
Journal Article
2016-01-0476
Yongchang Du, Yingping Lv, Yujian Wang, Pu Gao
Brake squeal is a complex dynamics instability issue for automobile industry. Closed-loop coupling model deals with brake squeal from a perspective of structural instability. Friction characteristics between pads and disc rotor play important roles. In this paper, a closed-loop coupling model which incorporates negative friction–velocity slope is presented. Different from other existing models where the interface nodes are coupled through assumed springs, they are connected directly in the presented model. Negative friction slope is taken into account. Relationship between nodes’ frictional forces, relative speeds and brake pressure under equilibrant sliding and vibrating states is analysed. Then repeated nodal coordinate elimination and substructure modal coordinate space transformation of system dynamic equation are performed. It shows that the negative friction slope leads to negative damping items in dynamic equation of system.
2016-04-05
Journal Article
2016-01-1298
Shukai Yang, Zuokui Sun, Yingjie liu, Bingwu Lu, Tao Liu, Hangsheng Hou
This work carried out a detailed analysis and optimization regarding a front disc brake squeal issue. Specifically, it explained the stability theory of complex modes for brake squeal simulation, constructed a brake system finite element model, established a simulation analysis methodology, determined the key parameters for evaluating the stability of the brake system complex modes, and carried out a model verification measurement with the SAE 2521 procedure. Finally, in order to resolve a specific 1800 Hz low frequency brake squeal issue, an optimization simulation was carried out. The obtained solutions were validated by the experimental findings.
2016-04-05
Journal Article
2016-01-1299
Robert S. Ballinger
The complex eigenvalue analysis has been used by the brake research community to study friction-induced squeal in automotive disk brake assemblies. The analysis process uses a nonlinear static pre-stressed normal modes analysis simulation sequence followed by a complex eigenvalue extraction algorithm to determine the dynamic instabilities. When existing brake hardware exists, good correlation between analysis results and experimental data can be obtained. Consequently, complex eigenvalue analysis can be a valuable method in an effort to understand brake components that might have a propensity to influence the noise behavior of a brake system. However, when hardware does not exist and the complex eigenvalue method is asked to be predictive, it becomes a difficult, if not impossible task. This paper will focus on some of the reasons the complex eigenvalue analysis method is not a reliable predictor of friction-induced squeal in automotive disk brake assemblies.
2016-04-05
Journal Article
2016-01-1315
Yongchang Du, Yingping Lv, Yujian Wang, Pu Gao
Closed-loop coupling model, based on complex eigenvalue analysis, is one of the most popular and effective methods for brake squeal analysis. In the model, coupling springs are used to represent the normal contacting force between coupled nodes. This assumption is the foundation of the model. But the physical meaning of coupling spring was seldom discussed and there’s no systematic method to determine the value of spring stiffness. This paper presents a new closed-loop coupling disc brake squeal model based on finite element component model and modal synthesis technique. Different from the traditional model, where the two nodes in a coupled node-pair are connected through a spring, in the new model they are assumed to be remain contacted tightly during vibration. Details of the model, including force analysis, coordinate reduction and transformation and complex eigenvalue decomposition are given.
2016-04-05
Journal Article
2016-01-1635
Donald F. Tandy, Jung Bae, Jason Colborn, Clay Coleman
Recreational Off-Road Vehicles (ROVs) or side-by-sides have increased in popularity as they are available in many different sizes and performance characteristics from a host of manufacturers. The U.S. Federal Government, through the Consumer Product Safety Commission, is proposing a vehicle handling and a rollover resistance test for these vehicles. For the sake of repeatability, the proposed maneuvers are to be performed on a hard paved surface as opposed to the off road surfaces (i.e. grass, sand, dirt, mud. rocks, etc.) that these vehicles are designed to be operated on. Since ROV tires are designed for off road use only, their performance on an asphalt or concrete surface has not been studied in depth. This paper discusses a tire study conducted on a MTS Flat Trac II tire machine where forces and moments where measured at various speeds with a ROV tire. Repeated runs were made to look at how the tire performance characteristics change as they wear.
2016-04-05
Technical Paper
2016-01-0091
Hikaru Watanabe, Tsutomu Segawa, Takumi Okuhira, Hiroki Mima, Norishige Hoshikawa
This paper presents a custom integrated circuit (IC) on which circuit functions necessary for “Active Hydraulic Brake (AHB) system” are integrated, and its key component, “Current-to-Digital Converter” for solenoid current measurement. The AHB system, which realizes a seamless brake feeling for Antilock Brake System (ABS) and Regenerative Brake Cooperative Control of Hybrid Vehicle, and the custom IC are installed in the 4th-generation Prius released in 2015. In the AHB system, as linear solenoid valves are used for hydraulic brake pressure control, high-resolution and high-speed sensing of solenoid current with ripple components due to pulse width modulation (PWM) is one of the key technologies. The proposed current-to-digital converter directly samples the drain-source voltage of the sensing DMOS (double-diffused MOSFET) with an analog-to-digital (A/D) converter (ADC) on the IC, and digitizes it.
2016-04-05
Technical Paper
2016-01-0470
Wei Chen, Zhe Sun, Jun Zheng, Liang Pan, Xurong Yi
The muti-body dynamic modeling and simulation was widely used in the vehicle dynamics developing process. However, it is difficult to get the parameters of the vehicle in the early stage, especially for the hardpoints. This paper analyzed the relationship of the chassis suspension, steering systems and wheels, and proposed a new vehicle dynamic modeling method using MSC.ADAMS. A four-wheeled vehicle can be approximated as a vehicle consisting of four wheels and body. The wheels and the body are connected by rods, spring and shock absorber. Firstly, the modeling method analyzes the relationship between the suspension and the steering and wheels. Secondly, constraint equations are established in Adams/View to represent the movement of the wheel. Then, characteristic parameters obtained from the test are input for modeling and simulation, without considering the concrete structure of the suspension, hard points, etc.
2016-04-05
Technical Paper
2016-01-1552
Renato Galluzzi, Andrea Tonoli, Nicola Amati, Gabriele Curcuruto, Piero Conti, Giordano Greco, Andrea Nepote
The development of suspension systems has seen substantial improvements in the last years due to the use of variable dampers. In such solutions, the characteristic of active or semi-active devices is modified to meet desired constraints, such as comfort and road holding. Furthermore, the persisting goal of improving the efficiency of subsystems within the automotive chassis has favored the use of regenerative solutions, in which electric machines can be employed as generators to recover part of the energy otherwise dissipated as heat during cyclic excitation. Although linear electric actuators seem a straight-forward choice in vehicle vibration damping, their limited force density leads to the implementation of rotary machines together with additional transmission mechanisms to convert angular displacements into linear ones and vice versa. Regenerative suspensions present different issues that limit their efficiency, being inertial stiffening and friction the most challenging ones.
2016-04-05
Technical Paper
2016-01-0378
John George, Daniel Gross, Hamid Jahed, Ali Roostaei
The choice of an appropriate material model with parameters derived from testing and proper modeling of stress-strain response during cyclic loading are the critical steps for accurate fatigue life prediction of complex automotive sub-systems. Most Materials used in automotive structures exhibit combined hardening behavior and it is essential to capture this behavior in the CAE model in order to accurately predict the fatigue life. This study illustrates the strain controlled testing of materials coupons and calculation of material parameters from test data in for the combined hardening material model used in ABAQUS solver for the trailing arm of an automotive chassis system. Stress- Strain response curves and fatigue results from other simpler material models like linear kinematic hardening model, isotropic hardening model and linear material model with Neuber correction is also discussed in light of the respective fatigue theories.
2016-04-05
Journal Article
2016-01-0387
Yunkai Gao, Jingpeng Han, Jianguang Fang, Shihui Wang
A compiled method of the programmed load spectrum, which can simplify and accelerate the fatigue bench test of a car body, is proposed and its effectiveness is checked by the fatigue simulation. By using the multi-body dynamics model with a satisfactory accuracy, the virtual iteration is applied to cascade body loads from the wheel hubs. Based on the rain-flow counting method and statistics theory, the distributions of the body loads are analyzed, and then the programmed load spectrum is compiled and simplified. Through comparative study, the simulation results of random and programmed load spectrum are found to agree well with each other in terms of the damage distribution and fatigue life, which demonstrates the effectiveness of the presented method.
2016-04-05
Journal Article
2016-01-0420
Frank Anthony Cuccia, James Pineault, Mohammed Belassel, Michael Brauss
It is well known that manufacturing operations produce material conditions that can either enhance or debit the fatigue life of production components. One of the most critical aspects of material condition that can have a significant impact on fatigue life is residual stress (RS) [1,2]. When springs are manufactured, the spring stock may undergo several operations during production. Additional operations may also be introduced for the purpose of imparting the spring with beneficial surface RS to extend its fatigue life and increase its ability to execute the task it was designed to perform. The resultant RS present in production springs as a result of the various fabrication and processing operations applied can be predicted and modeled, however, RS measurements must be performed in order to quantify the RS state with precision.
2016-04-05
Technical Paper
2016-01-0381
Moorthy Senniappan, Rajendra More, Shreyas Bhide, Siddesh Gowda
In present scenario automobile manufacturers are forced to reduce the weight of each components through design optimization in a bid to enhance the fuel efficiency and load carrying capacity of the vehicle, however this approach may not be practical for all the parts in real life and the engineer will end up adding further mass to the component to enhance the strength of the component since considerable over load application in real world usage condition can damage the component drastically. In this paper, steering tie rod arm of a heavy commercial vehicle was taken as a case study. The Tie rod arm is a part which connects the wheel spindle with steering system linkage i.e. tie rod. Tie rod transfers the steered force from one wheel to another wheel and tie rod arm transfers the force from tie rod to wheel spindle to steer both the front wheels in same direction.
2016-04-05
Technical Paper
2016-01-1354
Dejian Meng, Lijun Zhang, Zhuoping Yu
The transient thermo-mechanical coupling dynamic model of ventilated disc brake with asymmetrical outer and inner thickness was established by means of Msc-marc software. In the model, pad back-plate was simplified a rigid surface with the same shape of brake lining and was bonded together with brake lining. Control node was set on the rigid surface and force equaled brake pressure was applied on control node, which X and Y direction displacement degrees of freedom were restricted. With distribution characteristics of disc temperature field, normal stress field and lateral thermo-elastic deformation and thickness for the evaluation, the impacts of brake pad constraints on brake thermo-mechanical coupling characteristics were analyzed. The simulation results show that the brake pad back plate is an important structure in brake thermo-mechanical coupling analysis, which can’t be ignored in simulation computing.
2016-04-05
Technical Paper
2016-01-0429
Paul Augustine, Timothy Hunter, Nathan Sievers, Xiaoru Guo
The performance of a structural design depends upon the assumptions made on input load. In order to estimate the input load, during the design stage of the suspension assembly of a BAJA car, designers invest immense amount of time and effort to formulate the mathematical model of the design. The theoretical formulations may include idealization errors which can affect the performance of the car as a final product. These errors in estimating design load will lead to more weight or less strength than needed. This discrepancy between the assumed input load and the actual load from the environment can be eliminated by performing a real life testing process using load recovery methodology. Commercial load cells exist in industry to understand the real world loading of structures. A limitation of load cells is that the structure needs to be modified to accept the load cell and not all desired loading can be measured.
2016-04-05
Technical Paper
2016-01-0430
Joel Metz, Xin Zhang, Xiao Yu
The Front Lower Control Arm (FLCA) is a key part of the automotive suspension for performance and safety. Most FLCA designs attach to the front subframe using rubber handling and riding bushings, which determine the vehicle dynamics and comfort. In this paper, a design for a compliance bushing using a metal pin structure is discussed. The inner portion of the compliance bushing is a hollow metal collar with a layer of rubber, and the FLCA pin structure is pressed into the rubber. For safety requirements, the bushings must meet a pin push-in and push-out force requirement. During the development of the bushing design, different test groups conducted tests to determine if manufactured parts meet the push-out force specification. Each group tested at a different load rate and generated different maximum push out force values. The push-in/out speed was found to have a strong influence on the generated maximum load.
2016-04-05
Journal Article
2016-01-0444
Kemal Çalışkan, Mina M.S. Kaldas, Roman Henze, Ferit Küçükay
This paper presents a performance analysis study for the Rule-optimized Fuzzy-Logic controller of a Semi-active Suspension system. The Rule-optimized controller uses a Fuzzy Logic scheme which offers new opportunities in the improvement of vehicle ride performance. An eleven degree of freedom full vehicle ride dynamics model is constructed and validated through laboratory tests performed on a hydraulic four-poster shaker. An optimization process to obtain the optimum Fuzzy Logic membership functions and the optimum rule-base of the semi-active suspension controller is proposed. Discrete optimization has been performed with a Genetic Algorithm (GA) to find the global optima of the cost function which considers the ride comfort and road holding performance of the full vehicle.
2016-04-05
Technical Paper
2016-01-0446
Chen Liang, Guolin Wang, Zhou Zheng
A three-dimensional finite element model of radial tire 205/55R16,established by ABAQUS software,is used to simulate tire force and moment properties. Drum tests are designed to validate the simulation model’s reliability. To investigate the impacts of PCR contour design theory on tire force and moment, a modified string balance contour theory is presented, based on string balance contour theory, which simplifies the belts pressure share ratio as trapezium. And a program for calculating tire’s contour is compiled. Different tire contours are designed according to different belt pressure share ratios. One of the contours is selected according to the positive affect to cornering stiffness. Compare the selected newly designed tire with the original one, it is found that the newly designed tire’s contact area, longitudinal stiffness,lateral stiffness,camber stiffness and cornering stiffness increase while its radial stiffness decreases.
2016-04-05
Technical Paper
2016-01-0456
Zhaozhong Zhang, Dongpu Cao
This paper analyses how a human driver interacts with the steer-by-wire (SBW) controller using a simplified driver-vehicle-SBW system model. Driver model includes three main parameters: driver preview time, driver time delay and driver control gain. Driver neuromuscular dynamics are also considered using a simple transfer function. Simulation analyses and parametric studies have been conducted to draw conclusions for offering valuable information for SBW control design when considering driver-SBW collaborations.
2016-04-05
Technical Paper
2016-01-0455
Hongyu Zheng, Jinghuan Hu, Shuo Yang
With the development of auto industry and electronic control technology, the automobile steering system is developing to the intelligent direction. Steering system is turning from traditional machinery or hydraulic steering system to the electronic control steering such as electronic power steering, active front wheel steering, steer-by-wire system and so on. Steer-by-wire system removes the mechanical structure between steering wheel and steering vehicle wheel and uses electric signal to realize the steering intention of driver. Steer-by-wire technology makes the vehicle can be controlled not only by steering wheel but also by the joystick, button, touch screen and so on.
2016-04-05
Technical Paper
2016-01-0460
Salem A. Haggag, Abraham Mansouri
The control of automotive braking systems performance and wheel slip is a challenging problem due to the nonlinear of the braking process, vehicle body dynamics during braking and the tire-road interaction. When the wheel slip is not between the optimal limits during braking, the desired tire-friction force cannot be achieved, which influences the braking distance, the loss in steerability and maneuverability of the vehicle. A simple and in the same time realistic vehicle longitudinal braking model is essential for such challenging problem. In this paper, a new longitudinal rolling/braking lumped-vehicle model that takes vehicle aerodynamic forces in consideration is presented. The proposed model takes the rolling resistance force, the braking force and the aerodynamic lift and drag forces in consideration and investigates their impact on the vehicle longitudinal dynamics especially vehicle braking stopping distance and time.
2016-04-05
Journal Article
2016-01-0462
Chunlei Wang, Xinjie Zhang, Konghui Guo, Fangwu Ma, Dong Chen
With the development of the advanced driver assistance system and autonomous vehicle techniques, a precise description of the driver’s steering behavior with mathematical models has attracted a great attention. However, the driver’s steering maneuver demonstrates the stochastic characteristic due to a series of complex and uncertain factors, such as the weather, road, and driver’s physiological and psychological limits, generating negative effects on the performance of the vehicle or the driver assistance system. Hence, this paper explores the stochastic characteristic of driver’s steering behavior and a novel steering controller considering this stochastic characteristic is proposed based on stochastic model predictive control (SMPC). Firstly, a search algorithm is derived to describe the driver’s road preview behavior.
2016-04-05
Technical Paper
2016-01-1554
Cheng Gu, Xinbo Chen, Jun Yin
A novel geared electromagnetic active suspension was proposed in this paper, recycling the vibration energy and without hydraulic lines group. A rocker arm and a push rod were introduced to transfer the suspension vertical motion to the rotational motion of the motor, utilizing the high power density of rotational motor. Comparing with the common ball-screw active suspension, it owned advantages of simple structure and easy manufacturing. As the state variables of the suspension system could not all obtained, an output feedback LQR optimal controller was adopted, in which, the vehicle body acceleration, suspension deformation, tyre displacement and active force were weighted as the performance evaluations.
2016-04-05
Technical Paper
2016-01-0464
Lingyang Li, Wei Wu, Ji Chen, Jianpeng Shi, Xicheng Wang, Liuhua Qian
In order to expand the product design and development capabilities of Electric Power Steering (EPS) system, a passenger car's simulation model integrated with EPS system model will be made, and do some analytical investigation in this paper. Through simplifying the architecture model of EPS system, the mathematical equation expressions of steering wheel and column, worm gear reducer, rack and pinion, steer-wheels, brushed DC electrical motor, and ECU assistance and compensation laws will be described. A number of tests on the EPS full system and subsystems and components will be executed. The tests' results will be used as the input parameters of the model, and then be used for model validations. After that, the EPS system model will be created. Since the most important part of control logic strategy is the top secret of steering assembly supplier and it could't be provided to OEM in details or not even a black-box model directly.
2016-04-05
Technical Paper
2016-01-0469
Hyunkoo Kang, Wooyong Jung, Choon Lee
This paper presents payload estimation based on experimental friction coefficients identification. To estimate exact payload mass, dynamic mathematical model such as actuator dynamics and front linkage dynamics is derived by using Newton-Euler method. From the dynamic equation, nonlinear terms are analyzed and transformed. And a friction model is derived from the experiments with various conditions which have three states; boom joint angle, head and rod chamber pressures. It can identify friction coefficients and compensate friction forces. In addition, the accuracy of payload estimation system is verified through the field test.
2016-04-05
Journal Article
2016-01-0468
Jiageng Ruan, Paul Walker, Nong Zhang, Guangzhong Xu
Regenerative braking has been widely accepted as a feasible option to extend the mileage of electric vehicles (EVs) by recapturing the vehicle’s kinetic energy instead of dissipating it as heat during braking. The regenerative brake force provided by a generator is applied on the wheels in an entirely different manner compared to the traditional hydraulic-friction brake system. Drag torque and efficiency loss may be generated by transmitting the braking force from motor, axles, differential and, specifically in this paper, a two-speed dual clutch transmission (DCT) to wheels. Additionally, motors in most battery EVs (BEVs) and hybrid electric vehicle (HEVs) are only connected to front or rear axle. Consequently, conventional hydraulic brake system is still necessary, but dynamic and supplement to motor brake, to meet particular brake requirement and keep vehicle stable and steerable during braking.
2016-04-05
Technical Paper
2016-01-0474
Shukai Yang, Bingwu Lu, Zuokui Sun, Yingjie Liu, Hangsheng Hou
An low frequency vibration issue around 3.5 Hz surfaces during a truck program development process, and it is linked to uncomfortable driving and riding experiences. This work focuses on an analytical effort to resolve the issue by first building a full vehicle MBS model,and then carrying out a vibration response analysis. The model validation is performed using the full vehicle testing in terms of structural modes and frequency response characteristics. In order to resolve the issue which is considered to be excited mainly by the tire non-uniformity, the influence of the cab suspension, frame modes, front leaf spring system and rear balance suspension are analyzed. The root cause of the issue is found to be the rear balance suspension system, and the final optimization effort establishes the resolution measure for the issue.
2016-04-05
Technical Paper
2016-01-0092
Stijn Kerst, Barys Shyrokau, Edward Holweg
Active safety systems can be made more efficient, more robust and less complex if wheel load information would be available. This data can be obtained via different methods as for instance wheel force transducers or ‘smart tyres’. Both approaches however have difficulties related to usage in active vehicle dynamics control. The first approach, based on strain measurements in the rim, is too expensive for series application whilst the latter, based on accelerometers inside the tire, suffers from difficulties regarding its estimation bandwidth. In this paper a novel approach for the determination of wheel loading is proposed. The novel approach, based on strain measurements on the surface of the bearing outer-ring, is tested on both a dedicated bearing test setup as well as on a test vehicle. As a case study, a pure load based Anti-lock Braking algorithm is tested, which demonstrates that the novel approach provides the accuracy and bandwidth needed for active vehicle dynamics control.
2016-04-05
Technical Paper
2016-01-1555
Jack Ekchian, William Graves, Zackary Anderson, Marco Giovanardi, Olivia Godwin
It is widely anticipated that autonomous vehicles will offer increased productivity and convenience by freeing all occupants from the responsibility of driving. However, studies indicate that the occurrence of motion sickness in autonomous vehicles will be substantially higher than in conventionally driven vehicles. Occupants of autonomous vehicles are more likely to be involved in performing tasks and activities, such as reading, writing and using a computer or tablet, that typically increase the occurrence of motion sickness. The authors present a novel high bandwidth active suspension system, GenShock®, and tailored control algorithms targeted toward mitigating motion sickness in autonomous vehicles. GenShock actuators can actively push and pull the wheels of a vehicle in order to keep the chassis level and reduce heave, pitch, and roll motion.
2016-04-05
Technical Paper
2016-01-1546
Dongpil Lee, Kyongsu Yi, Bongchoon Jang, Sehyun Chang, Byungrim Lee
This paper describes a reference steering feel tracking algorithm for Electric-Power-Steering (EPS) system. Development of the EPS system with intended steering feel has been time-consuming procedure, because the feedforward map-based method has been applied to the conventional EPS system. However, in this study, a three-dimensional reference steering feel surface, which is determined from current vehicle states, is proposed. In order to track the proposed reference steering feel surface, sliding mode approach is applied to second-order steering dynamics model considering a coulomb friction model. An adaptive technique is utilized for robustness against uncertainties. In order to validate the proposed EPS control algorithm, hardware-in-the-loop simulation (HILS) has been conducted with respect to various steering tests (Weave, Transition, Flick, and Return-ability). It is shown that the reference steering feel is realized well by the proposed EPS control algorithm.
2016-04-05
Technical Paper
2016-01-1542
Shaosong Li, Jiafei Niu, Ren Sheng, Zhixin Yu, Shunhang Zheng, Yongfa Tu
Road feeling is the reaction force of steering wheel felt by the driver when the driver steers and this force contains the motion and force of vehicle and ties. Good road feeling is indispensable feedback information for the driver. The decrease in the strength of road feeling can make the driver feel that the on-center area is too large. Meanwhile the steering torque reacted by steering wheel cannot truly reflect the steering reaction torque, which is the so-called “poor linearity of steering force” and “fuzzy of road feeling” in subjective evaluation. With motor and reduction mechanism applied to Electric Power Steering (short for EPS) system of automobile, the frictional loss torque of steering system is increased. The friction compensation control based on the sign function or stature function of the angular velocity of motor is added to the electric power steering system to reduce the frictional loss torque of steering system.
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