FISITA World Congress 2021 - Technical Programme最新文献

{"title":"Parameter Identification of mathematical-empirical Tire Models using Measurement Data of a Wheel Force Transducer","authors":"Martin Schünemann, H. Heidfeld, S. Koch, C. Daniel, E. Woschke","doi":"10.46720/f2020-vdc-064","DOIUrl":"https://doi.org/10.46720/f2020-vdc-064","url":null,"abstract":"\"In research and development, the use of model-based methods has been established widely. In spite of the required costs and time for modelling and parameterization, the models become applicable in many steps of the design process from concept studies until parameter optimization. Particularly, during the early phase of the development of products or functions, it is necessary to keep time and cost efforts as low as possible without significantly reducing the quality of the simulation results. For the development of vehicle dynamic controls, the quality of the used models depends highly on the modelling of the wheel-road contact. Due to the reduced parameterization and calculation effort, mathematical-empirical or semi-physical approaches as well as flexible belt-ring models are preferred to simulate severe driving manoeuvres such as full braking with ABS intervention or the ISO 3888 double lane-change. The determination of the model parameters is carried out using special tire test rigs in which the tire and rim are clamped. Due to the complex experimental setup and the required infrastructure, these tests are very cost-intensive. In driving tests with real vehicle, commercially available wheel force transducers are used today. By means of force measuring elements, which are usually attached to an especially manufactured and split rim body, the transmitted forces and moments are determined while driving. A high-resolution angle sensor detects the rotation angle and the angular velocity of the wheel in order to transform the measured quantities (forces and torque at the wheel) from the rotating to the vehicle related coordinate system. At the beginning of the paper, established concepts of tire test rigs for determining the parameters of mathematical-empirical tire models will be summarized and compared with the proposed usage of a wheel force transducer in real-driving tests. This will include an estimation of the boundary conditions and the reproducibility of the measurements as well as influencing factors on the force transmission. Subsequently, the test equipment and driving manoeuvres that were carried out with the test vehicle are presented. In addition to the wheel force transducer, a 2-axis optical speed sensor is added to the test setup. Using the measured vehicle velocity and the measured wheel speed the tire slip can be calculated now. The measurement data is partly used for parameter identification of two simplified tire models according to PACEJKA and BURCKHARDT, which describe the steady-state friction coefficient slip characteristic. Since these are nonlinear tire models, a non-linear least squares algorithm is used as the mathematical optimization method. The measurement data, which was not used for the parameterization, are applied in the subsequent validation of the tire model. On the basis of the obtained results a statement about the usability of a parameterized tire model based on measurements with a wheel force transducer is","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127229867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Autonomous Driving Decision-making Based on the Combination of Deep Reinforcement Learning and Rule-based Controller","authors":"Jinzhu Wang Jinzhu Wang, Jie Bai Jie Bai, Libo Huang Libo Huang, Huanlei Chen Huanlei Chen","doi":"10.46720/f2021-acm-108","DOIUrl":"https://doi.org/10.46720/f2021-acm-108","url":null,"abstract":"As autonomous vehicles begin to drive on the road, rational decision making is essential for driving safety and efficiency. The decision-making of autonomous vehicles is a difficult problem since it depends on the surrounding dynamic environment constraints and its own motion constraints. As the result of the combination of deep learning (DL) and reinforcement learning (RL), deep reinforcement learning (DRL) integrates DL's strong understanding of perception problems such as visual and semantic text, as well as the decision-making ability of RL. Hence, DRL can be used to solve complex problems in real scenarios. However, as an end-to-end method, DRL is inefficient and the final result tend to be poorly robust. Considering the usefulness of existing domain knowledge for autonomous vehicle decision-making, this paper uses domain knowledge to establish behavioral rules and combine rule-based behavior strategies with DRL methods, so that we can achieve efficient training of autonomous vehicle decision-making models and ensure the vehicle to chooses safe actions under unknown circumstances. First, the continuous decision-making problem of autonomous vehicles is modeled as a Markov decision process (MDP). Taking into account the influence of unknown intentions of other road vehicles on self-driving decisions, a recognition model of the behavioral intentions of other vehicles was established. Then, the linear dynamic model of the conventional vehicle is used to establish the relationship between the vehicle decision-making behavior and the motion trajectory. Finally, by designing the reward function of the MDP, we use a combination of RL and behavior rules-based controller, the expected driving behavior of the autonomous vehicle is obtained. In this paper, the simulation environment of scenes of intersections in urban roads and highways is established, and each situation is formalized as an RL problem. Meanwhile, a large number of numerical simulations were carried out, and the comparison of our method and the end-to-end form of DRL technology were discussed. \"Due to its robust operation and high performance during bad weather conditions and overnight as well as the ability of using the Doppler Effect to measure directly the velocity of objects, the radar sensor is used in many application fields. Especially in automotive many radar sensors are used for the perception of the environment to increase the safety of the traffic. To increase the security level especially for vulnerable road users (VRU’s) like pedestrians or cyclists, radar sensors are used in driver assistance systems. Radar sensors are also used in the infrastructure, e.g. a commercial application is the detection of cars and pedestrians to manage traffic lights. Furthermore, radar sensors installed in the infrastructure are used in research projects for safeguarding future autonomous traffic. The object recognition and accuracy of radar-based sensing in the infrastructure can be increased ","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123604257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Rollover Stability in Consideration of Dynamic Oversteer Tendency","authors":"F. Chang, Matthias Bayer, S. van Putten, G. Prokop","doi":"10.46720/f2020-vdc-041","DOIUrl":"https://doi.org/10.46720/f2020-vdc-041","url":null,"abstract":"\"The trends towards increasing popularity of high performance SUVs require a novel assessment of “trade-off” between driving dynamics and rollover stability, which represents a new challenge for chassis design in the concept phase of chassis development. However, the rollover behavior has been typically investigated by means of experimental test maneuvers with prototype vehicles, which require a large amount of resources, such as measuring equipment, outrigger and roof loading. Besides, measurement data with measurement errors do not always provide satisfactory results due to external disturbance factors, e.g. environmental temperature and road surface. By contrast, a simulation environment can rule out the part of the aforementioned disturbance factors by reproducible simulation maneuvers in order to reduce the development expenses and obtain a better understanding of the rollover behavior. Within a cooperation project between Audi AG (Germany) and TU Dresden (Germany) five previous works have focused on the vehicle modeling, model verification, validation, analysis methodology and physical effect chains analysis for rollover behavior. However, a study into existing literature reveals that the interaction between yaw instability and roll instability has not been investigated sufficiently to date. Especially the question arises, to what extent the oversteer tendency (lateral instability) affects the rollover behavior (roll instability). Therefore, this paper aims to analyze the motion couplings between yaw and roll dynamics to explain the interrelation between oversteer tendency and rollover behavior, using the developed nonlinear two-track model with full axle kinematics and compliance, a dynamic steering and a nonlinear tire model. Firstly, a new criterion to describe the dynamical oversteer tendency in the nonlinear limit range of driving dynamics has been defined, which can be regarded as a further development of the traditional definitions of oversteer tendency in the linear range. Secondly, the rollover criticality has been quantified by means of a new maneuver in order to gain a comprehensive comparison between different vehicle configurations. Subsequently, different chassis parameters of the reference vehicle have been varied to investigate the relationship between driving performance and rollover stability. Finally, the results of the study are interpreted and discussed. Through analysis in this paper, the driving dynamics both in the linear and nonlinear range are evaluated to identify the operation principles between dynamical oversteer tendency and the rollover behavior. Summarizing the acquired know-how together, recommendations for design targets in the early phase of chassis development are derived. Newsworthy: 1. A new criterion to describe the dynamical oversteer tendency in the nonlinear limit range of driving dynamics 2. Systematical investigation of the interaction between oversteer tendency and rollover behavior 3. Parameter","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115031283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Human vs. Automation - Who Drives the Future?","authors":"V. Jirovský","doi":"10.46720/f2020-acm-044","DOIUrl":"https://doi.org/10.46720/f2020-acm-044","url":null,"abstract":"Human species is currently standing on a junction, where it shall decide how it will further develop new technologies. Within the rapid technological evolution during last hundred years, human was designing technology to support him in many challenges - to lift heavier things, to reach further distances, to heal more people. With introduction of IT technologies, numerous visionary high-tech solutions entered homes. High capacity modern communication technologies allow human not only to share large amount of data, but also not to share any information - people share bytes, but according to social scientists they don't share valuable information as they did in past. While i.e. standard for road vehicle brakes had 8 pages in 1970s, current print has more than 80, but does not contain 10 times more information. Human has silently entered an era, where technology is often created for technology, not for human. In today's daily life, it is much more difficult to find valid and valuable information in data smog. Similar applies to road transportation - a socio-technological system, whose control is widely decentralized. We are searching for solutions to enhance transport safety and to increase infrastructure throughput in new technologies, while we forget that transport is not the source of the problem, but the consequence of human's need to move. Thus, the solution is not on a technological level, but on a system organization level. One of the highly promoted technological solution is autonomous driving. However, if we study the literature we cannot find anything explaining the automation as the only right way and as an achievable solution to road transport problems. No in-depth interdisciplinary study exist about the influence of autonomous road transportation on the society. The numbers showing positive expectations have more economical and marketing background, rather than technological or social. Every new product or prototype is being promoted with standard marketing approach. MIT's social study on management in technological companies points out incompetent decision making on high levels of management primarily due to complexity of modern technological systems, which cannot be understood neither by one CEO, nor by number of narrow oriented specialists. Still, the evolution of autonomous systems in the past decade is at least interesting. We are already attacking physical limits of sensors. New algorithms have to pursue the chase for low energy demands. Yet, the human brain needs just about 25 Watts at full load, while it is able to perform highly complex and accurate probabilistic estimations. When driving a road vehicle, average driver does a mistake emerging into an accident once in ca. 270 000 km. This leads to an average driver's reliability of 99,99996% on a driven distance. According to several accident researches, majority of accidents is caused by minority of drivers. The proposed article is aiming to discuss the achievable safety benefit","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115207044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical and physical experiments on the passby noise of the iShare","authors":"Charalampos Tsimis, Xavier Montané","doi":"10.46720/f2020-mcf-005","DOIUrl":"https://doi.org/10.46720/f2020-mcf-005","url":null,"abstract":"\"This paper presents the work of an R&D project which aims to augment IDIADA’s capabilities in the prediction of aerodynamically generated passby noise via CFD simulations. The project focuses on the noise generated by the A-pillar and the side view mirror of IDIADA’s iShare concept car and combines numerical and experimental investigations. The objective is to develop and validate the numerical aeroacoustics methodology, as well as to develop an experimental methodology that makes use of IDIADA’s semi-anechoic chamber. The main numerical methodology used was based on the surface integral formulation of Ffowcs Williams-Hawkings, this is an acoustic analogy which splits up the problem to the local noise generation first and to the propagation of the acoustic wave second. For the local noise generation two approaches were used, a compressible and an incompressible one. The latter assumes that the acoustic field has a negligible effect on the hydrodynamic flow field, which simplifies the physics involved. The technique uses the theory of Acoustic Perturbation Equations to model the acoustic field that is generated by the flow of an incompressible fluid. The solver used was STAR-CCM+. Parallel to the numerical methodology development the project developed an experimental methodology. This involved the design of a nozzle that could channel the available flow of the semi-anechoic chamber into a high velocity jet that could be directed towards the A-pillar or the side view mirror of a vehicle, thus focusing the noise generation in these features. Finally, the numerical tests were compared to the experiments for validation. The paper will present the numerical and experimental SPL measurements in an array of microphones placed 0.6m away from the left hand side of the iShare, as well as, CFD visualisations of the flow field generated and of the noise sources. The numerical results follow the trends of the experimental results, but for certain frequency octaves there was a small deviation in the predicted SPL. Overall the agreement was satisfactory. This work has shown the potential of the methodologies used to solve aeroacoustics problems and the limitations of what can be tested in IDIADA’s semi-anechoic chamber and of the numerical methods. The paper will elaborate in detail on these findings. This is a new field for IDIADA, and it offers a new aeroacoustic validation case for numerical codes to be compared against.\"","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115572486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupling Apollo with the CommonRoad Motion Planning Framework","authors":"Xiao Wang, Anna-Katharina Rettinger, M. Althoff, Md Tawhid Bin Waez","doi":"10.46720/f2020-acm-019","DOIUrl":"https://doi.org/10.46720/f2020-acm-019","url":null,"abstract":"The development of autonomous vehicles requires extensive testing of software modules. Developing a reliable software platform which allows testing on a real vehicle is yet a challenging task. Therefore, open-source software platforms are becoming more important for researchers in the field of autonomous driving. For example, Baidu provides the open-source autonomous driving platform Apollo which aims to accelerate testing and deployment of autonomous vehicles. However, the complex software structure hinders an easy integration of developed software modules, especially the motion planning module. Moreover, Baidu's Apollo provides only one possibility to test one's own algorithms in simulation, namely to upload the algorithm in Baidu's cloud platform, which is unacceptable for most autonomous driving companies. In contrast, the open-source CommonRoad benchmark suites contain diverse testing scenarios, e.g., highway, urban, dense traffic, and interaction with bicyclists and pedestrians. In addition, CommonRoad provides a motion planning framework in Python which enables rapid planner prototyping, along with additional tools, e.g., efficient collision checker, map format converter, and interface with the traffic simulator SUMO. In this work, we introduce a Python API between the planning module of the Baidu Apollo platform and the CommonRoad software framework. The developed interface aims to bridge the gap between rapid prototyping for safe planning algorithms and real-time test drives. The API transfers perception and map information to the planner and then returns the planned trajectory. The users can either replace the Apollo planner with their own planner or integrate their planner as a fail-safe planner if the planned trajectory by Apollo is unsafe. With our interface, developers can first test their planners in diverse scenarios from the CommonRoad benchmark, and directly on a real vehicle afterwards using the Apollo platform. The latter can be performed without adapting their algorithms to Apollo software structures. Moreover, developers can record their test drives in CommonRoad format for offline analyses. We demonstrate our interface in several scenarios with increasing complexity.","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"273 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116068523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of Hybrid real-time capable Vehicle Simulation Platform for Energy Management Strategy Development and Virtual Validation","authors":"Pedro Manuel Maroto, D. de Lima, Danilo Mendes, M. Mammetti, P. Bauer, Joan Calres Bruno","doi":"10.46720/f2021-adm-143","DOIUrl":"https://doi.org/10.46720/f2021-adm-143","url":null,"abstract":"Model-based calibration enables a shift in development tasks from the real world to the virtual world, allowing for increased system robustness while reducing development costs and time. These benefits are especially pronounced in the case of complex powertrain systems such as Hybrid Electric Vehicles (HEV). In (P)-HEV, Energy Management Strategy (EMS) constitutes the core for fuel consumption and emissions reduction of hybrid electric vehicles. This paper presents an assessment of the feasibility of carrying out automated model calibration within a virtual powertrain test environment for EMS validation. It highlights the accuracy of the engine simulation model under steady-state and transient operating conditions. It also demonstrates the integration of the model with data based pollutant emission models and the after-treatment system. The Internal Combustion Engine (ICE) is modeled by means of the so called Mean Value Engine Model approach (MVEM) with limited amount of input signals. Electrical components are modeled following a classical map-based approach. The novelty of this methodology resides in the pollutant emissions models. Engine out emissions (CO2, CO, HC and NO) are modeled through convolutional neural networks (CNN) giving extremely accurate results, both in instantaneous and cumulative prediction. This allows to calibrate a Three-Way Catalyst model (TWC) enabling the characterization of a complete powertrain system model with fuel consumption, emissions (CO2, CO, HC and NOx) and the electrification part. In this framework EMS can be developed for minimizing not only fuel consumption but also pollutant emissions. As final step, advanced EMS based on reinforcement learning is proposed. The methodology is developed in a co-simulation framework between MATLAB-Simulink and AMESIM. The resulting model runs between 2-3 times faster than real time in an off-the-shelf laptop. This enables the methodology for developing models suitable for HIL (hardware-in-the-loop) and SIL (software-in-the-loop) applications. The final error in predicted pollutant emissions in the studied cycles remains below 2.5% in the case of CO2 emissions, 3.5% in the case of NOx emissions, and below 8.5% when speaking about CO and HC emissions.","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122860783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A New Quantitative Criterion for Vibration Comfort Assessment of Vehicles","authors":"Milad Abbasi Milad Abbasi, Hossein Salmani Hossein Salmani, M. Fard, R. Jazar","doi":"10.46720/f2020-mcf-049","DOIUrl":"https://doi.org/10.46720/f2020-mcf-049","url":null,"abstract":"A newly introduced comfort indicator was defined as the discomfort criterion (DiC). Based on several real-life driving scenarios and realistic assumptions. This criterion identified the comfort of a vehicle quantitatively, and therefore, it is possible to compare different types of vehicles in terms of ride comfort. The criterion was proposed in accordance with part one of the ISO 2631standard for mechanical vibration and shock evaluation of human exposure to whole-body vibration. Also, road surface conditions were extracted from ISO 8608 for mechanical vibration road surface profiles by applying the power spectral density (PSD) of a specific road class. Knowing that during the ride of a vehicle, occupants are exposed to vibrations from the road surface which causes the feeling of discomfort, reduces working ability, which in the long run can affect health in an adverse manner; a parametric optimization technique was then used to investigate the effects of vibrations on comfort of occupants to maintain oscillations in an acceptable zone in accordance with ISO 2631 standard. In the following, the effectiveness of the proposed measure was investigated throughout the suspension optimization of different vehicle types including electric vehicles which almost doubled the unsprung mass by adding an electric motor to the wheel assembly. In line with this analysis, a spatial oscillatory model of a typical vehicle with eight degrees of freedom was developed and utilized. Then, the root-mean-square value of the weighted vertical acceleration exposure to the driver's seat position was calculated in the range of 1-80 Hz. The exceedance from the reduced comfort limit (in accordance with ISO 2631 standard) and wheel travel of the vehicle were considered as design objectives. Finally, the optimum condition and impact factor of the design variables, i.e. suspension and driver's seat damping coefficients and stiffnesses were investigated. The results of this study showed the effectiveness and convenience of the proposed methodology. Moreover, this study is significant form a boarder perspective as a preliminary framework to develop a vehicle comfort rating system in the near future.","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117287211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of Advanced Engine Brake for Heavy-Duty Vehicles","authors":"Ondrej Bolehovsky, R. Tichánek, M. Takáts, Z. Syrovátka","doi":"10.46720/f2020-adm-063","DOIUrl":"https://doi.org/10.46720/f2020-adm-063","url":null,"abstract":"In the world of heavy-duty vehicles, the retarding capability is of high interest, as the natural retarding power and braking force per vehicle weight is only about one-tenth and a half of the passenger vehicles respectively. This is why such vehicles use an auxiliary braking device, either a drivetrain retarder or an engine brake. It brings not only the safety benefit, but also the economic one, as it prolongs service intervals of friction brakes and the vehicle can go downhill at higher speed with sufficient safety reserve. As the operational vehicle fuel economy improves, the natural vehicle retarding power decreases. For this reason, the performance and torque characteristic of the auxiliary braking systems need to be improved as well. The work focuses on the development of an advanced engine brake system, which works in two-stroke cycle. The development process utilized both the simulation and experimental techniques. A project partner simultaneously proposed a new valve train design, but this development is beyond the scope of this paper. The simulation phase started with a 1-D model of a serial production heavy-duty Diesel engine, at which both the experiment and new valve train design proposal aimed. The model underwent partial calibration, mainly in terms of discharge coefficient and engine and manifold geometry, as combustion is not of interest in the engine brake mode. Parameterized advanced valve actuation in the model enabled the optimizing tool to arbitrarily modify the valve lift profiles without colliding issues. The optimizer used several constraining parameters that are given either by requirements of the valve train mechanism or have an impact on stress and durability of engine components. Resulting valve lift profiles fulfilling the constraints showed braking performance which exceeds the nominal positive power output of the engine and outdoes the contemporary 4-stroke engine brake, particularly at low engine speed. The final valve lift profiles were then inputted into the mechanical model of the proposed valve train mechanism and checked for dynamics behavior. After that, the model kinematics produced final cam profiles and technical documentation was prepared for camshafts manufacturing. The camshafts were then mounted in the engine together with the newly designed valve train mechanism designed by a project partner. Due to cost and dynamometer possibilities, the experiment had to be performed only on selected cylinders. For this reason, a numerical torsional model of the engine crank-train coupled to the dynamometer helped determine proper engine layout and safety operating points of the engine. The engine was then equipped with fast and slow sensors and data acquisition system. The subsequent experiment yielded data for further re-calibration and validation of the 1-D model. The experiment confirmed correctly proposed valve lift profiles and performance prediction and also revealed unexpected phenomena during the gas excha","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129541972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization based design of an UKF vehicle state estimator","authors":"H. Heidfeld, Martin Schünemann","doi":"10.46720/f2020-vdc-090","DOIUrl":"https://doi.org/10.46720/f2020-vdc-090","url":null,"abstract":"For years the trend has been towards automated and assisted driving, for which vehicle dynamic control is needed. Effective vehicle dynamic control requires exact knowledge of the vehicle motion state and the road conditions, which usually comes from state estimators. As vehicle dynamics models often are nonlinear, the design of those estimators can be a difficult task. The Unscented Kalman Filter is a powerful tool for nonlinear state estimation. Besides the selection of an appropriate model, the choice of covariance matrices is main task in the design phase. For this, optimization-based tuning has become a state of the art method. Often minimization of the estimation error is done, for example with global optimization methods [1]. However, this approach does not fully take into account the stochastic properties of the estimated variables, which can result in implausible covariance estimations. Addressing this problem, different approaches for optimization-based tuning arepresented in this paper using the example of an UKF state observer for a four-wheel drive electric vehicle [2], [3]. First, details on the used vehicle model as well as the estimator implementation are given. Then optimization and validation are carried out using data from driving tests in a vehicle simulation including various severe maneuvers and varying road conditions. Last, the results are compared and discussed.","PeriodicalId":174936,"journal":{"name":"FISITA World Congress 2021 - Technical Programme","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129856387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}