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Viewing 121 to 150 of 10663
2016-04-05
Technical Paper
2016-01-1552
Renato Galluzzi, Andrea Tonoli, Nicola Amati, Gabriele Curcuruto, Piero Conti, Giordano Greco, Andrea Nepote
Abstract The development of suspension systems has seen substantial improvements in the last years due to the use of variable dampers. Furthermore, the efficiency increase in the subsystems within the automotive chassis has led to the use of regenerative solutions, in which electric machines can be employed as generators to recover part of the energy otherwise dissipated. However, the harvesting capability of regenerative suspensions is often limited by friction and inertial phenomena. The former ones waste mechanical energy into heat, while the latter ones hamper the shock absorption by locking the suspension when subject to dynamic excitation. Besides a suitable design and sizing of components, recent research works highlight the use of the so-called motion rectifier to improve energy recovery by constraining the motion of the electric motor to a single sense of rotation.
2016-04-05
Technical Paper
2016-01-1549
Nicola Bartolini, Lorenzo Scappaticci, Francesco Castellani, Alberto Garinei
Knocking noise is a transient structural noise triggered by piston rod vibrations in the shock absorber that excite the vibration of chassis components. Piston rod vibrations can be caused by valve motion (opening and closing) and dry friction during stroke inversions. This study investigates shock absorber knocking noise in twin tube gas-filled automotive shock absorbers and its aim is to define an acceptance criterion for a sample check of the component. If, in fact, the damper comes from a large mass production, it may happen that small mounting differences lead to different behaviors that result in higher or lower levels of knocking noise. To achieve this goal, experimental tests were carried out using a hydraulic test bench; accelerometers were placed in proximity to the rebound valve and on the piston rod. The vibration phenomenon was then isolated through a post-processing analysis and a damped and unforced lumped mass model was used to characterize the vibration.
2016-04-05
Technical Paper
2016-01-1550
Ming Peng, Xuexun Guo, Junyi Zou, Chengcai Zhang
Abstract This paper presents a novel application of hydraulic electromagnetic energy-regenerative shock absorber (HESA) into commercial vehicle suspension system and vehicle road performance are simulated by the evaluating indexes (e.g. root-mean-square values of vertical acceleration of sprung mass, dynamic tire-ground contact force, suspension deflection and harvested power; maximum values of pitch angle and roll angle). Firstly, the configuration and working principle of HESA are introduced. Then, the damping characteristics of HESA and the seven-degrees-of-freedom vehicle dynamics were modeled respectively before deriving the dynamic characteristics of a vehicle equipped with HESA. The control current is fixed at 7A to match the similar damping effect of traditional damper on the basis of energy conversion method of nonlinear shock absorber.
2016-04-05
Technical Paper
2016-01-1557
Francesco Castellani, Nicola Bartolini, Lorenzo Scappaticci, Davide Astolfi, Matteo Becchetti
Abstract Shock absorber is one of the most relevant sub-systems of the suspension system for a wide range of vehicles. Although a high level of development and tuning has been reached, in order to ensure high safety standards in almost every situation, some dynamic phenomena affecting vehicle handling or NHV (Noise Vibration Harshness) can appear. The aim of present work is to improve a mathematical model using experimental data from a prototype of monotube shock absorber developed for research purposes. The model takes into account all the main features affecting the global performance of the device, such as non-linear behaviour and the presence of hysteresis loops. Actually, the most important parameters are analyzed, such as flow and orifice coefficients of the valves, coefficients of mechanical compliance of the chambers and oil compressibility, dry and viscous friction coefficients.
2016-04-05
Technical Paper
2016-01-1559
Francesco Vinattieri, Tim Wright, Renzo Capitani, Claudio Annicchiarico, Giacomo Danisi
Abstract The adoption of Electrical Power Steering (EPS) systems has greatly opened up the possibilities to control the steering wheel torque, which is a critical parameter in the subjective and objective evaluation of a new vehicle. Therefore, the tuning of the EPS controller is not only becoming increasing complicated, containing dozens of parameters and maps, but it is crucial in defining the basic DNA of the steering feeling characteristics. The largely subjective nature of the steering feeling assessment means that EPS tuning consists primarily of subjective tests on running prototypes. On account of that, this paper presents an alternative test bench for steering feeling simulation and evaluation. It combines a static driving simulator with a physical EPS assisted steering rack. The end goal is to more accurately reproduce the tactile feedback to the driver by including a physical hardware in lieu of complicated and difficult to obtain software models.
2016-04-05
Technical Paper
2016-01-1554
Cheng Gu, Xinbo Chen, Jun Yin
Abstract A novel geared electromagnetic active suspension is proposed in this paper. A pushing rod and a rocker are introduced to transfer the suspension vertical motion to the rotational motion of the motor. Comparing with the common ball-screw active suspension, it presents advantages of simple structure, easy manufacturing and module design. As the state variables of the suspension system cannot be all obtained for the sake of cost, taking the suspension deflection as the measurement, an output feedback LQR optimal controller is adopted, and it is concluded that the system can be stable with damping. Considering the nonlinearity of equivalent stiffness and unsprung mass caused by the system structure, parameter perturbation ranges are concluded through dynamic analysis, and robust H∞ control algorithm is proposed to realize the multi-objective optimization.
2016-04-05
Technical Paper
2016-01-1564
Shyama Ashok kumar S
Abstract Field Oriented Control (FOC) has been widely used for controlling Brushless DC motors (BLDC) used in Electric Power Assisted Steering (EPAS) systems. This is majorly because FOC provides better performance at lower speed, compared to other algorithms available in market. But the design complexities and cost of EPAS ECUs are much higher due to transformations and the rotor position sensor involved. This paper suggests the use of Direct Torque Control (DTC) over FOC, due to its quicker dynamic response, lower complexity and better response at higher speed. A simple Ripple Reduction Strategy (RRS) with data smoothening and filtering is introduced to improve the performance at lower speed. The DTC with RRS is modeled in MATLAB /Simulink. The Simulation results are compared with that of FOC, to prove the effectiveness of DTC.
2016-04-05
Technical Paper
2016-01-1565
Joydeep Banerjee, John McPhee
Abstract Dynamic modelling of the contact between the tires of automobiles and the road surface is crucial for accurate and effective vehicle dynamic simulation and the development of various driving controllers. Furthermore, an accurate prediction of the rolling resistance is needed for powertrain controllers and controllers designed to reduce fuel consumption and engine emissions. Existing models of tires include physics-based analytical models, finite element based models, black box models, and data driven empirical models. The main issue with these approaches is that none of these models offer the balance between accuracy of simulation and computational cost that is required for the model-based development cycle. To address this issue, we present a volumetric approach to model the forces/moments between the tire and the road for vehicle dynamic simulations.
2016-04-05
Technical Paper
2016-01-1561
Xinxin Shao, Haiping Du, Fazel Naghdy
Abstract Development of a passive anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) with the advantage of improving vehicle directional stability and handling quality is presented. A 7 degrees-of-freedom full car model and a 20 degrees-of-freedom anti-pitch anti-roll hydraulically interconnected suspension model dynamically coupled together through boundary conditions are developed and used to evaluate vehicle handing dynamic responses under steering/braking maneuvers. The modeling of mechanical subsystem is established based on the Newton’s second law and the fluid subsystem is modelled using a nonlinear finite-element approach. A motion-mode energy method (MEM) based on the calculation of the motion-mode energy is employed to investigate the effects of an anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) system on vehicle body-wheel motion-mode energy distribution.
2016-04-05
Technical Paper
2016-01-1542
Shaosong Li, Jiafei Niu, Ren Sheng, Zhixin Yu, Shunhang Zheng, Yongfa Tu
Abstract 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 common friction compensation control through the sign function of angular velocity or the saturation function of angular velocity is conducted to reduce the frictional loss torque of steering system. However, when the motor used in steering system generates assist torque based on the common friction compensation control, the longitudinal intercepts of steering torque change obviously at different steering wheel angles. The driver will get different frictional loss torque of steering system at different steering wheel angle. The information of steering torque contains the change of steering reaction torque and the frictional loss torque of steering system, so the change of frictional loss torque can cause the fuzzy of road feeling.
2016-04-05
Technical Paper
2016-01-1547
Jun Yin, Xinbo Chen, Lixin Wu, Jianqin Li
Abstract Traditional active suspension which is equipped with hydraulic actuator or pneumatic actuator features slow response and high power consumption. However, electromagnetic actuated active suspension benefits quick response and energy harvesting from vibration at the same time. To design a novel active and energy regenerative suspension (AERS) utilizing electromagnetic actuator, this paper investigates the benchmark cars available on the market and summaries the suspension features. Basing on the investigation, a design reference for AERS design is proposed. To determine the parameters of the actuator, a principle is proposed and the parameters of the actuator are designed accordingly. Compared the linear type and rotary type Permanent Magnet Synchronous Motor (PMSM), the rotary type is selected to construct the actuator of the AERS. Basing on the suspension structure of the design reference model and utilizing rotary type PMSM, a novel AERS structure is proposed.
2016-04-05
Technical Paper
2016-01-1546
Dongpil Lee, Bongchoon Jang, Kyongsu Yi, Sehyun Chang, Byungrim Lee
Abstract 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 a typical steering test. It is shown that the reference steering feel is realized well by the proposed EPS control algorithm.
2016-04-05
Technical Paper
2016-01-1545
Huan Liu, Guoying Chen, Changfu Zong
Abstract A new electric power steering system (EPS) dynamic friction model based on normalized Bouc-Wen model is given, as well as its structure form and model features. In addition, experimental method is used to identify corresponding parameters. In order to improve road feel feedback, this paper analyzes the shortcoming of traditional constant friction compensation control method and proposes a variable friction compensation control method which the friction compensation current changes according to the assist characteristic gain. Through simulation and real vehicle test verification, variable friction compensation control method eliminates the effect of basic assist characteristic, and improves the driver’s road feel under high speed.
2016-04-05
Technical Paper
2016-01-1544
Dexin Wang, Frank Esser
Abstract Evaluation of electric steering (EPAS) system performance using vehicle specific load conditions is important for steering system design validation and vehicle steering performance tuning. Using real-time vehicle dynamics mathematical models is one approach for generating steering loads in steering hardware-in-the-loop (HIL) testing. However achieving a good correlation of simplified mathematical models with real vehicle dynamics is a challenge. Using rack force models from measured steering tie rod forces or from simulations using a high-fidelity vehicle dynamics model is an effective data-driven modelling method for testing EPAS systems under vehicle specific load conditions. Rack force models are identified from physical measurements or validated vehicle simulations of selected steering test maneuvers. The rack force models have been applied in steering system performance evaluation, benchmarking, and steering model validation.
2016-04-05
Technical Paper
2016-01-1602
Suad Jakirlic, Lukas Kutej, Daniel Hanssmann, Branislav Basara, Cameron Tropea
The present work deals with a computational study of a ‘DrivAer’ car model, the rear-end shape of which corresponds to the Notchback configuration (Heft et al. [1] and Heft [2]). The study investigates the effects of the underbody geometry and wheel rotation on the aerodynamic performance. The configurations with detailed and smooth underbody as well as with stationary and rotating wheels are considered. The computational model applied relies on a VLES (Very Large Eddy Simulation) formulation, Chang et al. [3]. The residual turbulence related to the VLES framework is presently modelled by a RANS-based (Reynolds-Averaged Navier-Stokes), four-equation (D(k,ɛ,ζ, f)/Dt) near-wall eddy-viscosity model, Hanjalic et al. [4].
2016-04-05
Technical Paper
2016-01-1573
Ken Archibald, Kyle Archibald, Donald Neubauer
Abstract This paper will document a rationale for wheel straightening based on the rise of declining roads, increased consumer preference for lower profile tires, unintended consequences of wheel customization and the reduction in energy consumption. A recommended patented procedure detailing how A356-T6 wheels can be straightened will be presented. To validate the recommended procedure a sample of wheels was uniformly deformed and straightened and subsequently tested per SAE J328 and SAE J175. Test results are provided that indicate straightened wheels should be fully serviceable in their intended service. A laboratory protocol to replicate the wheel flange cracks is described. The protocol is used to demonstrate that wheels without deformations do not result in flange cracks. Conversely wheels with deformations in excess of 1.5mm do result in cracks at less than 750,000 cycles.
2016-04-05
Technical Paper
2016-01-1576
Federico Ballo, Gianpiero Mastinu, Massimiliano Gobbi
Abstract Mass minimization is a key objective for the design of racing motorcycle wheels. The structural optimization of a front motorcycle wheel is presented in the paper. Topology Optimization has been employed for deriving optimized structural layouts. The minimum compliance problem has been solved, symmetry and periodicity constraints have been introduced. The wheel has been optimized by considering several loading conditions. Actual loads have been measured during track tests by means of a special measuring wheel. The forces applied by the tire to the rim have been introduced in an original way. Different solutions characterized by different numbers of spokes have been analyzed and compared. The actual racing wheel has been further optimized accounting for technological constraints and the mass has been reduced down to 2.9 kilograms.
2016-04-05
Technical Paper
2016-01-1575
Federico Ballo, Roberto Frizzi, Gianpiero Mastinu, Donato Mastroberti, Giorgio Previati, Claudio Sorlini
Abstract In this paper the lightweight design and construction of road vehicle aluminum wheels is dealt with, referring particularly to safety. Dedicated experimental tests aimed at assessing the fatigue life behavior of aluminum alloy A356 - T6 have been performed. Cylindrical specimens have been extracted from three different locations in the wheel. Fully reversed strain-controlled and load-controlled fatigue tests have been performed and the stress/strain-life curves on the three areas of the wheel have been computed and compared. The constant amplitude rotary bending fatigue test of the wheel has been simulated by means of Finite Element method. The FE model has been validated by measuring the strain at several points of the wheel during the actual test. From the FE model, the stress tensor time history on the whole wheel over a loading cycle has been extracted.
2016-04-05
Technical Paper
2016-01-0014
Shun Yang, Weiwen Deng, Haizhen Liu, Rui He, Lei Qian, Wenlong Sun, Ji Gao
Abstract Nowadays, the vehicle market puts forward urgent requirement for new kinds of braking booster because the traditional vacuum booster cannot meet the demands of new energy vehicles anymore. However, one problem that all the new plans should face is how to guarantee an ideal pedal feeling. In this paper, a novel mechatronics braking booster is proposed, and servo motor introduced into the booster makes the assist rate can be adjusted under a great degrees of freedom, so the structural parameters and control parameters of the booster should be determined elaborately to get an optimal pedal feeling. The pedal feeling is always represented by the pedal stoke-force curve which is influenced by different parameters.
2016-04-05
Technical Paper
2016-01-0029
Chuanliangzi Liu, Bo Chen, Ming Cheng, Anthony Champagne, Keyur Patel
Abstract The Electronic Control Unit (ECU) of an Electric Power Steering (EPS) system is a core device to decide how much assistance an electric motor applies on a steering wheel. The EPS ECU plays an important role in EPS systems. The effectiveness of an ECU needs to be thoroughly tested before mass production. Hardware-in-the-loop simulation provides an efficient way for the development and testing of embedded controllers. This paper focuses on the development of a HiL system for testing EPS controllers. The hardware of the HiL system employs a dSPACE HiL simulator. The EPS plant model is an integrated model consisting of a Vehicle Dynamics model of the dSPACE Automotive Simulation Model (ASM) and the Nexteer Steering model. The paper presents the design of an EPS HiL system, the simulation of sensors and actuators, the functions of the ASM Vehicle Dynamics model, and the integration method of the ASM Vehicle Dynamics model with a Steering model.
2016-04-05
Technical Paper
2016-01-0051
Hongyu Zheng, Mingxin Zhao
Abstract Electric power steering (EPS), active front wheel steering (AFS) and steer by wire systems (SBW) can enhance the handling stability and safety of the vehicle, even in dangerous working conditions. Now, the development of the electric control steering system (ECS) is mainly based on the way that combines the test of the electric steering hardware-in-loop (HIL) test bench with real vehicle tests. However, the real vehicle tests with higher cost, long cycle and vulnerable to space weather have the potential safety problems at early development. On contrast, electronic control steering HIL test bench can replace real vehicle tests under various working conditions and make previous preparations for real vehicle road tests, so as to reduce the number of real vehicle test, shorten the development cycle, lower development costs, which has gradually become the important link of research and development of electronic steering system.
2016-04-05
Technical Paper
2016-01-0093
Haizhen Liu, Rui He, Jian Wu, Wenlong Sun, Bing Zhu
Abstract With the development of modern vehicle chassis control systems, such as Anti-Lock Brake System (ABS), Acceleration Slip Regulation (ASR), Electronic Stability Control (ESC), and Regenerative Braking System (RBS) for EVs, etc., there comes a new requirement for the vehicle brake system that is the precise control of the wheel brake pressure. The Electro-Hydraulic Brake system (EHB), which owns an ability to adjust four wheels’ brake pressure independently, can be a good match with these systems. However, the traditional control logic of EHB is based on the PWM (Pulse-Width Modulation), which has a low control accuracy of linear electromagnetic valves. Therefore, this paper presents a research of the linear electro-magnetic valve characteristic analysis, and proposes a precise pressure control algorithm of the EHB system with a feed forward and a PID control of linear electro-magnetic valves.
2016-04-05
Technical Paper
2016-01-0132
Haizhen Liu, Weiwen Deng, Rui He, Jian Wu, Bing Zhu
Abstract Brake-by-wire (BBW) system has drawn a great attention in recent years as driven by rapidly increasing demands on both active brake controls for intelligent vehicles and regenerative braking controls for electric vehicles. However, unlike conversional brake systems, the reliability of the brake-by-wire systems remains to be challenging due to its lack of physical connection in case of system failure. There are various causes for the failure of a BBW system, such as failure of brake controller, loss of sensor signals, failure of communication or even power supply, to name a few. This paper presents a fault-tolerant control under novel control architecture. The proposed control architecture includes a driver command interpreter module, a command integration module, a control allocation module, a fault diagnosis module and state observers. The fault-tolerant control is designed based on a quadratic optimal control method with consideration of actuator constraints.
2016-04-05
Technical Paper
2016-01-0117
Bi-Cheng Luan, I-Hsuan Lee, Han-Shue Tan, Kang Li, Ding Yuan, Fang-Chieh Chou
Abstract This paper presents the design and implementation of a new steering control method for lane following control (LFC) using a camera. With the road information provided by the image sensor, the LFC system calculates the steering command based on the Target and Control (T&C) driver steering model. The T&C driver model employs a look-ahead control structure to capture the drivers’ core steering mechanism. Based on the models of the steering actuator and the vehicle dynamics, optimal control gains can be determined for any given look-ahead distance (normalized by the vehicle speed). With these simple gains, the vehicle can track very well along the center of the lane. This LFC system was first simulated under the Model-in-the-Loop (MiL) test using the CarSim simulation. The simulations show that the resultant lateral offsets are smaller than those from typical driver models.
2016-04-05
Technical Paper
2016-01-0146
Yonghwan Jeong, Seonwook Kim, Kyongsu Yi, Sangyong Lee, ByeongRim Jo
Abstract This paper represents a parking lot occupancy detection and parking control algorithm for the autonomous valet parking system. The parking lot occupancy detection algorithm determine the occupancy of the parking space, using LiDAR sensors mounted at each side of front bumper. Euclidean minimum spanning tree (EMST) method is used to cluster that information. After that, a global parking map, which includes all parking lots and access road, is constructed offline to figure out which cluster is located in a parking space. By doing this, searching for available parking lots has been finished. The proposed parking control algorithm consists of a reference path generation, a path tracking controller, and a parking process controller. At first, route points of the reference path are determined under the consideration of the minimum turning radius and minimum safety margin with near parking.
2016-04-05
Technical Paper
2016-01-0134
Sagar Behere, Xinhai Zhang, Viacheslav Izosimov, Martin Törngren
Abstract Heavy commercial vehicles constitute the dominant form of inland freight transport. There is a strong interest in making such vehicles autonomous (self-driving), in order to improve safety and the economics of fleet operation. Autonomy concerns affect a number of key systems within the vehicle. One such key system is brakes, which need to remain continuously available throughout vehicle operation. This paper presents a fail-operational functional brake architecture for autonomous heavy commercial vehicles. The architecture is based on a reconfiguration of the existing brake systems in a typical vehicle, in order to attain dynamic, diversified redundancy along with desired brake performance. Specifically, the parking brake is modified to act as a secondary brake with capabilities for monitoring and intervention of the primary brake system.
2016-04-05
Technical Paper
2016-01-0166
Hiroaki Kitano, Hitosugi Kazuo, Hideyuki Tanaka
Abstract Accuracy of positioning with GNSS (Global Navigation Satellite System) has been improved in recent years. Especially in Japan, high accuracy GNSS service, QZSS (Quasi Zenith Satellite System), will start in 2018 and the first QZS, “MICHIBIKI” has been already launched. They will broadcast correction data which enhances GNSS performance and realize cm-order positioning. In this paper, we, Mitsubishi Electric develop the estimation algorithm of vehicle position and attitude and also adapt the algorithm to a test vehicle which can trace automatically the calculated path with EPS (Electric Power Steering) and high accuracy GNSS. Although the GNSS receiver calculates the longitude and latitude of the vehicle every second, it is not enough to control vehicle dynamics smoothly. So we estimate vehicle position and attitude of the vehicle with GNSS and vehicle sensors in high frequency.
2016-04-05
Technical Paper
2016-01-0172
Tim Tudor, Kerry Tudor
This paper presents an investigation into the effect of front wheel steer geometry on steer induced load transfer. An inhouse mathematical model has been developed which quantifies and illustrates these effects. The model has also been used to predict how common geometry variables affect the resulting steer induced load transfer. It is shown that the effect of steer on overall load transfer is significant, especially for high roll stiffness vehicles, and that the effect may be used to manipulate vehicle handling balance. The paper also shows that the resulting load transfer can be controlled by utilising an upright mounted pushrod design and how such a configuration may also be used to control front ride height with steer. The relationships between common design variables and the resulting steer effect have been determined.
2016-04-05
Technical Paper
2016-01-0239
Li Zhou, Gangfeng Tan, Xuexun Guo, Ming Chen, Kangping Ji, Zhilei Li, Zhongjie Yang
Abstract The hydraulic retarder is an auxiliary braking device used in heavy duty vehicle. It generates braking forceby liquid damping effect and makes inertial energy into thermal energy of the transmission medium when the vehicleis in thedownhill. The traditional thermal management system of the hydraulic retarder dissipates the heat of transmission medium out of the vehicle directly, which causes a big waste of energy, meanwhilethe thermal management system components need to consume engine power. This study applies organic Rankine cycle (ORC)cooling system to meet the high power cooling requirements of the hydraulic retarder and recover waste heat energy from the transmission medium at the same time and then supply energy to the thermal management system, which could save the parasitic power of the engine and improve the comprehensive energy utilization ratio of the vehicle.
2016-04-05
Technical Paper
2016-01-0378
John George, Daniel Gross, Hamid Jahed, Ali Roostaei
Abstract 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 subsystems. Most materials used in an automotive substructure, like a chassis system, 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, with examples, the strain-controlled testing of material coupons, and the calculations of material parameters from test data for the combined hardening material model used in the Abaqus solver. Stress-strain response curves and fatigue results from other simpler material models like the isotropic hardening model and the linear material model with Neuber correction are also discussed in light of the respective fatigue theories.
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