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Viewing 61 to 90 of 86934
2018-04-03
Technical Paper
2018-01-0553
Jinwei Sun, Mingming Dong, Yechen Qin, Liang Gu
As the control parameter of the semi active suspension system varies with road profile, this paper proposed a new algorithm based on cuckoo search optimization method and road estimation to study the characteristic of the nonlinear parameters and at the same time improve riding comfort. Base on above purpose, a seven degree of freedom full vehicle model is developed with nonlinear damper and spring. The sprung mass acceleration, pitch acceleration and tire deflection can be chosen as the objective function, and the control current of semi active suspension are chosen as optimization variables. A multi-object cuckoo search algorithm was utilized to find the optimal parameters under different road profile, and a road estimation algorithm was used to identify the road level. Then the control parameters can be adjusted adaptively according to the level of the road. Computer simulations are carried out to illustrate the performance of the proposed algorithm.
2018-04-03
Technical Paper
2018-01-0550
Yechen Qin, yanjun Huang, Zhenfeng Wang, Mingming Dong
Road profile is the main input of vehicle system and its characteristics significantly influence vehicle performance, especially on the aspects of ride comfort, road handling, and fuel consumption. In fields of vehicle dynamics control and road network maintenance, Road observation becomes a hot topic and receives considerable attention over the last several years. To provide an easy applied yet accurate road classification method for automotive engineers, this paper presents a system response based road classifier with consideration of tire enveloping. For this purpose, tire enveloping effect is firstly modeled based on the flexible roller contact (FRC) theory, then transfer functions between road input and commonly used suspension responses i.e. sprung mass acceleration, unsprung mass acceleration and rattle space, are calculated for a quarter vehicle model.
2018-04-03
Technical Paper
2018-01-0551
Tommaso Novi, Alex Liniger, Renzo Capitani, Marco Fainello, Giacomo Danisi, Claudio Annicchiarico
Traditional vehicles are designed to be very stable and ensure no loss of control by the driver. High stability is formally translated into a large positive stability margin (SM) which leads to highly understeering vehicles. However, a increase in stability often causes a decrease in peak lateral grip. On the other hand, a lower SM can cause a greater phase lag in the vehicle’s frequency response which makes the control of a vehicle at limit handling conditions very complicated. With autonomous vehicles, the human factor is eliminated and, consequently, so is the need for high stability. Therefore, it could be possible to exploit the passive vehicle dynamics and enhance the performance, both in terms of peak grip and phase lag response. The goal of this paper is to explore the dynamic characteristics of a vehicle by comparing results of a vehicle with different levels of stability when driven by a human and an autonomous “driver” on a non-standard double lane change manoeuvre.
2018-04-03
Technical Paper
2018-01-0565
Lance Bredthauer, David Lynch
This paper studies the use of active rear steering (4-wheel steering) to change the transient lateral dynamics and body motion of passenger cars in the stable or linear region of the tires. Rear steering systems have been used for several decades to improve low speed turning maneuverability and high speed stability, and various control strategies have been previously published. With a model-based, feed-forward rear steer control strategy, the lateral transient can be influenced separately from the steady-state steering gain. This lateral transient is influenced by many vehicle parameters, but we will look at the influence of active rear steer and various tire types such as all-season, snow, summer, etc. This study will explore the ability for a rear steering system to change the lateral transient to a step steer input, compared to the effect of changing tire types.
2018-04-03
Technical Paper
2018-01-0563
Daigo Fujii, Hirokazu Yabumoto, Shingo Koumura
The active stabilizer not only controls the roll angle of the vehicle due to steering input, but also improves the riding comfort by reducing the roll vibration caused by the anti phase road surface input. As one of the past researches, the Roll Skyhook control was presented based on the Skyhook theory: It found that there is neither time lag nor phase delay in the controller, but that vibration in all frequency bands can be reduced. However, the time lag such as CAN signal transfer, computation and phase delay of low pass filter can cause undesirable vibration. Consequently, sufficient control effect is not obtained. In order to suppress the influence of the undesirable vibration, we used the wheelbase filtering that causes a frequency at which roll oscillation is minimal. Hence, we appropriately designed control signal filters considering roll-lateral coupled motions and conducted an experiment with an actual vehicle to confirm performance benefit.
2018-04-03
Technical Paper
2018-01-0564
Xing Yang, Lu Xiong, Bo Leng, Yue Li
A handing improvement algorithm based on motion tracking control is proposed for distributed drive electric vehicle which driving/braking torque of individual wheel can be control independently and accurately. An ideal reference model for motion tracking control is designed based on linear vehicle model with two degrees of freedom. According to the requirement of power steering, optimization characteristics of differential drive assisted steering are designed. The steering angle feed forward control is employed to improve yaw rate steady gain of reference model under the constraints of the motor external characteristics and the ideal characteristics of differential drive assist steering. Then an anti-windup PI control is proposed to track reference yaw rate by calculating the additional vehicle yaw moment. In addition, a torque distribution algorithm is presented to meet the driver’s intention during direct yaw torque control. Experiments under multiple maneuvers are carried out.
2018-04-03
Technical Paper
2018-01-0561
Haiyang Long
Suspension has a great influence on vehicle ride comfort and handling stability. How to improve the suspension performance has received more and more attention. To improve vehicle ride comfort, the MRF semi-active suspension is studied in this paper. Firstly, the dynamic calibration experiment of magnetorheological damper was carried out so that the mechanical property curves was obtained. According to the experimental results, the Bouc-Wen model of magnetorheological damper was identified and validated by Simulink Design Optimization. Secondly, The 1/4 the vehicle vibration model can be constructed and calculate the vibration differential equations. The suspension of the simulation model can be constructed by the use of Matlab/Simulink software. Basing on the established model, we can do deeply research on the active suspension control strategies under different road conditions and make related control strategies using the transfer function method.
2018-04-03
Technical Paper
2018-01-0559
Zhenfeng Wang, Yechen Qin, Mingming Dong, Zhenyu Wang, Liang Gu
The study of vehicle state estimation performance especially on the aspect of observer-based control for improving vehicle ride comfort and road handling is a challenging task for vehicle industry. Since vehicle roll behavior with various road excitations act an important part of driving safety, how to accurately obtain vehicle state under various driving scenes are of great concern. However, previous researches seldom consider coupling relation between vehicle vertical and lateral response with steering input under various road excitation. To address this issue, comprehension analyses on vehicle roll state estimation with coupled input are present in this paper. A full-car nonlinear Takagi-Sugeno (T-S) fuzzy model is first created to describe vehicle lateral and vertical coupling dynamics.
2018-04-03
Technical Paper
2018-01-0562
Sterling McBride, Corina Sandu, Angel Alatorre, Alessandro Victorino
One of the principal goals of modern vehicle control systems is to ensure passenger safety during dangerous maneuvers. Their effectiveness relies on providing appropriate parameter inputs. Tire-road contact forces are among the most important because they provide helpful information that could be used to mitigate vehicle instabilities. Unfortunately, measuring these forces requires expensive instrumentation and is not suitable for commercial vehicles. Thus, accurately estimating them is a crucial task. In this work, two estimation approaches are compared, an observer method and a neural network learning technique. Both predict the lateral and normal tire-road contact forces. The observer approach takes into account system nonlinearities and estimates the stochastic states by using an extended Kalman filter technique to perform data fusion based on the popular bicycle and the not often used hoverboard vehicle models.
2018-04-03
Technical Paper
2018-01-0560
Youpeng Zhang, Hongyu Zheng, Jiaxu Zhang, Cheng Cheng
This paper presents a fault-tolerant control(FTC) method for four-wheel independently driven and steered(4WID/4WIS) electric vehicles based on reconfigurable control allocation to increase the flexibility for vehicle control and improve the safety of vehicle after the steering motor failures. The proposed fault tolerant control method consists of the following three parts: 1) a fault detection and diagnosis (FDD) module that monitors vehicle steering condition, detects and diagnoses actuator failures; 2) a upper controller that computes the generalized forces/moments to track the desired vehicle motion and trajectory using model predictive control method; 3) a reconfigurable control allocator that optimally distributes the generalized forces/moments to four wheels. The FTC approach is based on the reconfigurable control allocation which reallocates the generalized forces/moments among healthy steering actuators and driving motors once the actuator failures is detected.
2018-04-03
Technical Paper
2018-01-0572
Chengshi wang, Yue wang, John R. Wagner
Emerging autonomous driving technology, with emergency navigating capabilities, necessitates innovative vehicle steering methods for operators during unanticipated scenarios. A reconfigurable “plug and play” steering system paradigm enables lateral control from any seating position in the vehicle’s interior. When required, drivers may access a stowed steering input device, establish communications with the vehicle steering subsystem, and provide direct wheel commands. Accordingly, the provision of haptic steering cues and lane keeping assistance to navigate roadways will be helpful. In this study, various steering devices have been investigated which offer reconfigurability and haptic feedback to create a flexible driving environment. A joystick and a robotic arm that offer multiple degrees of freedom were compared to a conventional steering wheel.
2018-04-03
Technical Paper
2018-01-0573
Bingrui Jia, Gary Heydinger, Scott Zagorski, Anmol Sidhu, Dennis Guenther
This paper presents the development of a CarSim model of an All-Terrain Vehicle (ATV) that can be used to predict the handling and stability characteristic of the vehicle. The inertia and suspension characteristics of a subject ATV are measured and a model of the ATV is built in CarSim based on the measurements. A simplified suspension model is developed to convert the suspension compliance measurements into parameters suitable to a CarSim model. Procedures used to apply vehicle mass, inertia and suspension kinematics data in CarSim are also shown. The model is evaluated using predictions of vehicle response during a constant radius circle test. The simulation results of the maneuver are compared with the field test results shown in a recent CPSC report on ATV’s. Similar cornering characteristics are found in both results. Modifications are made to the model to study how changes to the ATV affect performance.
2018-04-03
Technical Paper
2018-01-0570
Felix Ellensohn, Markus Schwienbacher, Joost Venrooij, Daniel Rixen
In periods of a growing relevance for automated driving, dynamic simulators present an appropriate simulation environment to repeat driving scenarios with good fidelity. A realistic replication of the driving dynamics is an important criterion to immerse persons in virtual environments provided by the simulator. Motion Cueing Algorithms (MCA) determine the simulator's input subject to the driving dynamics demand. The main limitations come from technical restrictions of the simulator's actuators. Typical dynamical simulators consists of a hexapod, exhibiting six degrees of freedom (DoF) to reproduce the vehicle motion in all dimensions. As its workspace dimensions are limited, an approach is to expand the simulator with redundant DoF by additional motion systems. This work introduces a global optimization scheme which is able to find an optimal motion for a driving simulator exhibiting three redundant degrees of freedom.
2018-04-03
Technical Paper
2018-01-0571
Xin Xia, Lu Xiong, Xuefeng Lin, Zhuoping Yu
Vehicle sideslip angle is significant for electronic stability control devices and hard to estimate due to the nonlinear and uncertain vehicle and tire dynamics. In this paper, based on the two track vehicle dynamic model considering the tire pneumatic trail variation, the vehicle sideslip angle estimation method was proposed. First, the extra steering angle of each wheel caused by kinematics and compliance characteristics of the steering system and suspension system was analyzed. The steering angle estimation method was designed. Since the pneumatic trail would vary with different tire slip angle, distances between the center of gravity and front&rear axle also change with the tire slip angle. Then, based on the dynamic pneumatic trail and estimated steering angle, we modified the traditional two track vehicle dynamic model using a brush tire model. This model matches the vehicle dynamics more accurately.
2018-04-03
Technical Paper
2018-01-0569
Wei Liu, Lu Xiong, Xin Xia
The estimation of vehicle key state which cannot be measured with ordinary vehicle-mounted sensors directly is the basic condition for vehicle motion following control. Especially, the accuracy and real time performance of the sideslip angle estimation have great influence on the control effect, which has been the focus in the vehicle state observation field. In this paper, the research status of the vehicle sideslip angle estimation methods is summarized: kinematics based method, dynamic based method, kinematics and dynamics fusion method, and multi-source sensors fusion method. The characteristic of different estimation algorithms is discussed. With new sensors equipment in intelligent vehicle such as GPS, camera and magnetometer, the new problems of the sideslip angle estimation including multi-rate sampling, measurement delay and attitude estimation are analyzed. Finally, the development trend of the sideslip angle estimation is prospected.
2018-04-03
Technical Paper
2018-01-0568
Mohamed A. A. Abdelkareem, Lin Xu, Junyi Zou, Mohamed Kamal Ahmed Ali, F. A. Essa, Ahmed Elagouz, Mohamed A. Hassan
Energy has the worldwide concern since the World War. Recently, the energy harvesting technology has got more attraction in different fields and applications. Hence, in a world where energy becomes rare and expensive, even the small quantities are worth to be harvested where it can be exploited in different applications. Vehicle suspension is one of the vibration power dissipation sources in which the undesired vibration is dissipated into heat waste. Accordingly, the principal motivation of this study is exploitation the conflict between the potentially harvested power and vehicle dynamics in automotive suspension system induced by road irregularity. Therefore, in terms of RMS conflict diagrams, the conflict between the potential power and vehicle dynamics are sufficiently and comprehensively defined considering a vehicle speed of 20 m/s.
2018-04-03
Technical Paper
2018-01-0567
Achyut Vemuri, Nitin Talekar, Bhaskar Avutapalli
Durability assessment for suspension systems requires loads on each component from different road profiles. These road loads are typically obtained by testing the vehicle on the proving grounds. If a new vehicle is to be assessed for durability early in the design phase, a prototype is required which can be time consuming and expensive. Given the large number of configurations offered in the truck industry, it is not practical to measure data for each one. The only options would be to depend on generic load cases or to use a virtual method that can translate limited measurements to various configurations. If the road profiles for the proving grounds can be captured based on measurements on a few vehicle configurations, then they can be applied to new CAE full vehicle models to obtain road loads for preliminary analysis.
2018-04-03
Technical Paper
2018-01-0583
Zhao Liu, Ping Zhu, Liwei Wang, Ching-Hung Chuang
Because of rising complexity during the automotive product development process, the number of disciplines to be concerned has been significantly increased. Multidisciplinary design optimization (MDO) methodology, which provides an opportunity to integrate each discipline and conduct compromise searching process, is investigated and introduced to achieve the best compromise solution for the automotive industry. To make a better application of MDO, the suitable coupling strategy of different disciplines and efficient optimization technique for automotive design are studied in this paper. Firstly, considering the characteristics of automotive load cases which include many shared variables whereas rare coupling variables, a multilevel MDO coupling strategy based on enhanced collaborative optimization is studied to improve the computational efficiency of MDO problems.
2018-04-03
Technical Paper
2018-01-0582
Junyi Zou, Xuexun Guo, Lin Xu, Mohamed A. A. Abdelkareem, Bian Gong, Jie Zhang, Gangfeng Tan
In this paper, a hydraulic interconnected suspension system (HIS) based on a hydraulic energy-regenerative shock absorber (HESA) is presented. At first, the structure and working principle of the suspension system is described in detail; secondly, the mathematic model of the suspension system is demonstrated to describe the hydraulic fluid characteristics, which means the relationship between the flow rate, flow velocity and oil pressure; then, a full vehicle model with 8-dof is built to research the dynamic characteristic of the HIS-HESA system; furthermore, a simulation model is established to carry out the parameter analysis of the suspension system; And in the simulation, the stability characteristic of the system is the main evaluation index, such as the anti-roll, anti-yaw, and anti-pitch performance, so the fishhook and the double lane change tests are considered as the working conditions of the simulation.
2018-04-03
Technical Paper
2018-01-0581
Wei HAN
BBW (Brake-by-wire) can increase the vehicle safety performance due to high control accuracy and fast response speed. As one solution of BBW, the novel Integrated-electro-hydraulic brake system (I-EHB) is proposed, which consists of electro-hydraulic booster and hydraulic pressure control unit. The electro-hydraulic booster is activated by an electric motor that driving linear motion mechanism to directly produce the master cylinder pressure. With electro-hydraulic booster as an actuator, the hydraulic pressure control problem is a key issue. Most literatures deal with the pressure control issue based on the feedback pressure signal measured by pressure sensor. As far as the authors are aware, none of the proposed techniques takes into account the pressure sensor unequipped BBW. In this paper, there is no pressure feedback signal, but there is only position feedback signal measured by position sensor for control law design.
2018-04-03
Technical Paper
2018-01-0579
Letian GAO, Lu Xiong, Xiang Gao
Cornering of skid-steered vehicles without steering mechanism is realized by differential drive/brake torque generated from in-wheel motors at left and right sides. Compared to traditional Ackerman steered vehicles, skid-steered vehicles consume much more energy while cornering due to greater steering resistance. So torque allocation is critical to the distributed drive skid-steered vehicles, since it influences not only steering performance, but also energy consumption. Most researches of torque allocation control for distributed drive electric skid-steered vehicles have paid much attention to tire force characteristics or efficiency characteristics of electric motors, however, torque allocation control based on unique dynamic characteristics of skid-steered vehicles are seldom studied.
2018-04-03
Technical Paper
2018-01-0577
Jieun Song
Suspension is a system which operates dynamically according to road condition unlike other system statically mounted to the body. Especially this is more remarkable in high performance vehicle because there are more high input from road to suspension than normal vehicle. For this reason, the tightening torque of suspension system of high performance vehicle is more important than other systems and normal vehicle. To support the clamping between parts against force from road when cornering, optimized tightening torque is required to maximize R&H performance. For this optimization, it should be conducted first to comprehend how much performance effects on vehicle by tightening torque.
2018-04-03
Technical Paper
2018-01-0576
Makoto Araki, Kazushi Akimoto, Toru Takenaka
In motorcycles travelling at middle or high speed, roll movement stability is usually maintained by restoration forces generated by self-steering effect. However, when the vehicle is stationary or travelling in low speed, sufficient restoring force does not occur because some of the forces such as the centrifugal force become small. In our study, we aimed at prototyping a motorcycle having roll stability when the vehicle is in stationary or low speed with a steer assist control, while maintaining stability properties in middle or high speed. A model was built to represent dynamics of roll movements, which is composed of a fixed point mass located above the vehicle’s center of gravity and another movable point mass below that gravity center. According to the model, when steered, the roll moment direction generated by the shift of the movable point mass becomes the same as the direction generated by the ground contact point shift of the front tire.
2018-04-03
Technical Paper
2018-01-0589
Daliang Shen, Dominik Karbowski
In this paper we present an optimal control algorithm for a connected and automated vehicle with a hybrid-electric powertrain for a cruising situation. Thanks to connectivity to the cloud and/or to infrastructure, speed limit and slope along the future route can be known with accuracy; this information can in turn be used to compute the control variable trajectory that will minimize energy consumption, without impacting travel time significantly. Because speed is affected by the choice of control variables (e.g. torque and gear), this concept can be applied in an automated driving scenario. In the first part of the paper, we provide an overview of theory used to solve this optimal control problem. We use quadratic models for the powertrain and apply the Pontryagin Minimum Principle, which reduces the problem to the minimization of a cost function with parameters called co-states.
2018-04-03
Technical Paper
2018-01-0590
Minghao Shen, Ting Jun Li, Weiwen Deng, Hongyu Zheng
On-ramp merging maneuver on highway requires slower passing velocity due to collision avoidance constraints. The slower velocity leads to the declination of traffic efficiency and more energy consumption. With the help of V2V technology, vehicles have access to state information of traffic vehicles and can cooperatively make decisions and motion planning. Platooning is an important application. In this article, we study a scenario where a platoon on ramp merges into another platoon on the main lane. We propose a systematic approach to planning and controlling the merging process, minimizing the energy consumption while ensuring driving safety. Due to strong coupling of system dynamics, the whole control process is made up of two consecutive steps. First a desired velocity is determined for vehicles to track, and the final merging order is planned using virtual vehicle method.
2018-04-03
Technical Paper
2018-01-0584
Junqi Yang, Ching-Hung Chuang, Zhenfei Zhan, Hongyi Xu, Gang Guo
This paper presents a design process with data mining technique and advanced optimization strategy. The proposed design method provides insights in three aspects. First, data mining technique is employed for sensitivity study to select key factors of design variables. Second, relationship between multiple types of size and shape design variables and performance responses can be investigated based on sufficient training data. Last but not least, design preference can be initialized based on data analysis to provide priori guidance for the starting design points of optimization algorithm. An exhaust system design problem which largely contributes to the improvement of vehicular Noise, Vibration and Harshness (NVH) performance is employed for the illustration of the process. . Two types of design parameters, structural variable (gauge of component) and layout variable (hanger location), are considered in the studied case.
2018-04-03
Technical Paper
2018-01-0586
Balakrishna Chinta, Srinivasa Mandadapu
Understanding customer expectations is critical to satisfying customers. Holding customer clinics is one approach to set winning targets for the engineering functional measures to drive customer satisfaction. In these clinics, customers are asked to operate and interact with vehicle systems or subsystems such as doors, lift gates, shifters, and seat adjusters, and then rate their experience. From this customer evaluation data, engineers can create customer loss or preference functions. These functions let engineers set appropriate targets by balancing risks and benefits. Statistical methods such as cumulative customer loss functions are regularly applied for such analyses. In this paper, a new approach based on the Taguchi method is proposed and developed. It is referred to as Taguchi Customer Loss Function (TCLF).
2018-04-03
Technical Paper
2018-01-0596
Sughosh Rao, Timothy Seitz, Venkata Raghava Ravi Lanka, Frank Barickman, Garrick Forkenbrock, Gary Heydinger, Dennis Guenther
With the emergence of Advanced Driver Assistance Systems (ADAS), an increase in the necessity of autonomous vehicle validation is observed. However, ADAS features are much more challenging to evaluate than traditional safety features, because an understanding of the feature's response at all possible scenarios is required. In this paper, one such ADAS feature, Traffic Jam Assist (TJA) is studied. This study focused on the longitudinal behavior of autonomous vehicles, while following a lead vehicle (LV) in traffic jam scenarios. The autonomous vehicle behavior is modeled using different car-following models. In this study, three vehicles were used: 2017 Mercedes E300, 2017 Tesla S 90D, and 2017 Volvo S90. The vehicles were tested for a typical traffic scenario, where the subject vehicle (SV) is following a LV. Under this scenario, two different velocity profiles were used, one for testing and another to validate.
2018-04-03
Technical Paper
2018-01-0597
Venkata Raghava Ravi Lanka, Sughosh Rao, Timothy Seitz, Frank Barickman, Garrick Forkenbrock, Dennis Guenther, Gary Heydinger
Adaptive Cruise Control (ACC) is one of the popular Advanced Driver Assistance Systems (ADAS) features, being widely implemented in many new generation vehicles. However, evaluating safety of ACC is still challenging and requires vehicles response at various scenarios. In this paper, a method for effectively evaluating ACC is presented. Effective evaluation of ACC requires underlying control architecture and for better understanding of it, two physics-based linear mathematical models are developed. These models estimate the response of ACC in a car-following scenario, i.e., predicting the longitudinal acceleration. Developed models are listed below: 1) Single Degree of Freedom Spring Damper Model (SDM). 2) Time to Collision(TTC). These developed models are fit to Naturalistic Driving Study dataset (NDS), part of Strategic Highway Research Program-2. Next, the models are fit to newer generation autonomous vehicle data which consists of vehicles possessing ACC.
2018-04-03
Technical Paper
2018-01-0592
Günter Ehmen, Björn Koopmann, Frank Poppen, Philipp Reinkemeier, Ingo Stierand
The application of digital control in the automotive domain clearly follows an evolution with increasing complexity of both covered functions and their interaction. Advanced Driver Assistance Systems (ADAS) and Automated Driving Functions (AD) comprise modular interacting software components that typically build upon a layered architecture. As these components are generally developed by different teams, using different tools for different functional purposes and building upon different models of computation, an integration of all components guaranteeing the satisfaction of all requirements calls for coherent handling of timing properties. We propose an approach addressing this major challenge, which consists of four design paradigms. A compositional semantic framework - based on a notion of components, their interfaces and their interaction - provides the common ground.
Viewing 61 to 90 of 86934