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How to model real-world driving behavior? Probability-based driver model for energy analyses

Daimler AG-Tobias Schuermann, Tobias Goedecke, Stefan Schmiedler, Daniel Goerke
University of Applied Sciences Esslingen-Kai André Boehm
  • Technical Paper
  • 2019-01-0511
To be published on 2019-04-02 by SAE International in United States
A wide variety of applications such as driver assistant and energy management systems are researched and developed in virtual test environments. The safe testing of the applications in early stages is based on parameterizable and reproducible simulations of different driving scenarios. One possibility is modelling the microscopic driving behavior to simulate the longitudinal vehicle dynamics of individual vehicles. The currently used driver models are characterized by a conflict regarding comprehensibility, accuracy and calibration effort. Due to the importance for further analyses this conflict of interests is addressed by the presentation of a new microscopic driver model in this paper. The proposed driver model stores measured driving behaviors with its statistical distributions in maps. Thereby the driving task is divided into free flow, braking in front of stops and following leading vehicles. This makes it possible to display the driving behavior in its entirety. The comprehensibility of this driver model is given by its simplicity and the calibration effort is low with existing measurement data. These data are recorded with a testing vehicle by a map-…

Development of a standalone application in MATLAB to generate brake performance data

Indian Institute of Technology, Madras-Harsh Kumar Singh
  • Technical Paper
  • 2019-01-0513
To be published on 2019-04-02 by SAE International in United States
Predicting the brake performance and characteristics is a crucial task in the vehicle development activity. Performance prediction is a challenge because of the involvement of various parts in the brake assembly like booster, master cylinder, calipers, disc and drum brakes. Determination of these characteristics through vehicle level tests requires a lot of time and money. This performance prediction is achieved by theoretical calculations involving vehicle dynamics. The final output must satisfy the regulations. This project involves the creation of a standalone application using MATLAB to predict the various brake performances such as: booster characteristics, adhesion curves, deceleration and pedal effort curves, behavior of brakes during brake and booster failed conditions and braking force diagrams based on the given user inputs. Previously, MS Excel and an application developed in the TK Solver environment was used to predict the brake performance curves. Debugging and inclusion of new modules was a major issue in old applications. Also, the previous applications lacked ABS module, which after the new government norms will be implemented in every vehicle. Thus, there was…

Sensitivity Analysis of Tire-Soil Interaction using Finite Element Analysis and Smoothed Particle Hydrodynamics Techniques

UOIT-Mirwais Sharifi, Moustafa El-Gindy
University of Ontario Institute of Technology-Zeinab El-Sayegh
  • Technical Paper
  • 2019-01-0174
To be published on 2019-04-02 by SAE International in United States
This paper presents the modelling, calibration and sensitivity analysis of LETE Sand using Visual Environment’s Pam Crash. LETE sand is modelled and converted from Finite Element Analysis mesh (FEA) to Smooth-particle hydrodynamics (SPH). The sand is then calibrated using terramechanics published data by simulating a pressure sinkage test and shear box test using the SPH LETE sand particles. The material properties such as tangent modulus, yield strength and bulk modulus are configured so the simulation’s results match those of theoretical values. Sensitivity analysis of the calibrated LETE sand material is then investigated. The sensitivity analysis includes mesh size, plate geometry, smoothing length, max smoothing length, artificial viscosity and contact thickness. The effect of these parameters on the sand behaviour is analyzed. Finally, SPH LETE Sand is used to determine the rolling resistance coefficient of RHD truck tire size 315/80R22.5 for different mesh size sand particles. The results found within this paper will be continued in regard to achieving better understanding of vehicle dynamics for tire-terrain interaction.

Hierarchical vehicle active collision avoidance based on potential field method

Changan Intelligent Vehicle R&D Center-Gang Yi
Chongqing University-Ling Zheng, Yinong Li, Wei Yang
  • Technical Paper
  • 2019-01-1016
To be published on 2019-04-02 by SAE International in United States
In this paper, a closed loop path planning and tracking control approach of collision avoidance for autonomous vehicle is proposed. The two-level model predictive control(MPC) is proposed for the path planning and tracking. The upper-level MPC is designed based on the simple vehicle kinematic model to calculate the collision-free trajectory and the potential field method is adopted to evaluate the collision risk and generate the cost function of the optimization problem. The lower-level MPC is the trajectory-tracking controller based on the vehicle dynamics model that calculates the desired control inputs. Finally the control inputs are distributed to steering wheel angle and motor torque via optimal control vectoring algorithm. Test cases are established on the Simulink/Carsim platform to evaluate the performance of the controller. The simulation results demonstrate that the proposed control has satisfactory path tracking performance and could avoid the potential collisions effectively during the high way driving.

Customer Oriented Vehicle Dynamics Assessment for Autonomous Driving in Highway

Centro Ricerche Fiat-Giovanni Gabiati
Fiat Chrysler Automobiles-Silvio Data
  • Technical Paper
  • 2019-01-1020
To be published on 2019-04-02 by SAE International in United States
Nowadays, thanks to continuous improvement in IT, carmakers spend great efforts on studies regarding Autonomous driving. Autonomous driving is the most advanced and focused research area for what concerns the automotive field and Carmakers are mainly investing money in this field but in most cases the analysis is centered towards the efforts on control logic, legal issues or possible benefits of autonomous driving. This paper’s objective is to evaluate the vehicle dynamic response of an autonomous driven vehicle, in particular, evaluation of vehicle/driver performance for a highway overtake maneuver. Obviously in this new scenario the vehicle will be driven autonomously, so performance evaluation means comfort evaluation. For this reason, the acceleration magnitude of peaks must be observed in a complete different logic eventually with new thresholds, as well as new magnitudes. Lateral acceleration variation (jerk) for example is going to be a key parameter for this evaluation. RMSs remain interesting indicators for comfort like the best practice for NVH evaluations, but in this kind of maneuvers horizontal accelerations should also be considered. In this very…

An Innovative Test System for Holistic Vehicle Dynamics Testing

FKFS-Jens Neubeck
MTS Systems Corp.-Ford Boone, Wilbur Kan
  • Technical Paper
  • 2019-01-0449
To be published on 2019-04-02 by SAE International in United States
In the automotive industry, there is a continued need to improve the development process and handle the increasing complexity of the overall vehicle system. One major step in this process is a holistic approach on both simulation and testing. For example, knowledge of the complete vehicle behavior is getting increasingly important for the development of new control concepts like integrated vehicle dynamics control aiming to improve handling quality and ride comfort. However, with classic test systems, only separated and isolated aspects of vehicle dynamics can be evaluated. To address these challenges and link simulation and testing even closer, the Institute of Internal Combustion Engines and Automotive Engineering, University of Stuttgart is introducing a new Handling Roadway (HRW) Test System in cooperation with FKFS and MTS Systems Corporation. The HRW allows testing of a vehicle’s combined longitudinal, lateral and vertical characteristics and therefore provides the possibility to supplement road testing with holistic vehicle testing under laboratory conditions. IVK, FKFS and MTS agreed to establish the HRW system in order to jointly advance the state-of-the-art laboratory evaluation…

A HiL Test Bench for Monocular Vision Sensors and its Applications in Camera-Only AEBs

CATARC-Pan Song, Rui Fang, Bolin Gao, Dongchao Wei
  • Technical Paper
  • 2019-01-0881
To be published on 2019-04-02 by SAE International in United States
Advanced Driver Assistance System (ADAS) uses a class of environmental sensors, e.g. LiDAR, RADAR, cameras, to obtain information about surrounding traffic objects. By processing this information in real time, the control algorithm in the ADAS decision-making level then makes decisions according to different warning, assistance, and/or motion-planning strategies. The executive layer responds to the target commands to finally implement different ADAS functions. Theoretically, the vision sensor alone, which is usually mounted on the interior of the front windshield of a vehicle, can support the system requirements of ADAS applications in many directions. Among many types of vision sensors, the monocular vision sensor has become the first choice for most ADAS products due to its lower cost, higher reliability, and easier installation for calibration. This paper describes the design and establishment of a Hardware-in-the-Loop (HiL) test bench for monocular vision sensors. The virtual test scenarios are built in the CarSim software. The animated pictures in accordance with the position and direction of the vision sensor installation are simulated in a host computer and projected at actual…

The Kinematic Analysis of Occupant Excursions and Accelerations During Staged Low Speed Far-Side Lateral Vehicle-to-Vehicle Impacts

Engineering Systems Inc.-Peggy Shibata, Julius Roberts, James Sprague, Alyson Light, Jacob Stegemann, Manuel Meza-Arroyo, Shawn Capser
  • Technical Paper
  • 2019-01-1030
To be published on 2019-04-02 by SAE International in United States
The collection of research that examines and characterizes occupant kinematics during low speed lateral vehicle-to-vehicle impacts is far less comprehensive than the much larger body of literature that quantifies the occupant kinematics associated with low speed rear end impacts. In order to augment the available data, a series of 44 low speed far-side lateral vehicle-to-vehicle impacts were conducted in a laboratory setting. A combination of accelerometers and 3D motion tracking technology was used to capture the vehicle dynamics of the target and bullet vehicles and to characterize the collision. The target vehicle was initially stationary; the bullet vehicle impacted the target vehicle at the front passenger side door. The bullet vehicle pre-impact speeds over all tests ranged from 2.5 to 5.5 mph. Nine volunteers participated in the study. Volunteers were seated in the driver seat during the impacts and were outfitted with accelerometers on their head and lower back and wore reflective markers for 3D motion tracking on the left side of their body. The design of experiment included conducting lateral impacts while the volunteers…

Route Optimized Energy Management of a Connected and Automated Multi-mode Hybrid Electric Vehicle using Dynamic Programming

Michigan Technological University-Neeraj Rama, Huanqing Wang, Joshua Orlando, Darrell Robinette, Bo Chen
  • Technical Paper
  • 2019-01-1209
To be published on 2019-04-02 by SAE International in United States
This paper presents a methodology to optimize the blending of Charge Depleting (CD) and Charge Sustaining (CS) modes in a multi-mode plug-in hybrid electric vehicle (PHEV) that reduces overall energy consumption when the selected route cannot be drive purely electric. The PHEV used in this investigation is the second generation Chevrolet Volt and as many as four instrumented vehicles were utilized simultaneously on road to acquire validation data. The optimization method utilized is dynamic programming (DP) and is paired with a reduced fidelity propulsion system and vehicle dynamics model to enable compatibility with embedded controllers and be computationally efficient of the optimal blended operating scheme over an entire drive route. The objective of the optimizer is to enable future Connected and Automated Vehicles (CAVs) to best utilize onboard energy for minimum energy consumption based on velocity and elevation profile information from Intelligent Transportation Systems (ITS), Internet of Things (IoT), High-Definition Mapping, and onboard sensing technologies. Emphasis is placed on runtime minimization to quickly react and plan a truly optimal mode scheme to highly dynamic road…

Laboratory Experiments Using Event Data Recorder and Additional Data from CAN Bus

Reata Engineering-Michael Farrugia
University of Malta-Miguel Tabone, Jean Paul Azzopardi, Mario Farrugia
  • Technical Paper
  • 2019-01-0635
To be published on 2019-04-02 by SAE International in United States
An experimental campaign based on the harness and Event Data Recorder (EDR) of a production vehicle (Toyota Auris 2007) was setup for laboratory experiments. The experiments involved triggering minor events in the EDR by hitting the Airbag Control Module (ACM) with a pendulum style impactor with different pendulum weight, initial angle, front and rear. The ACM was hit in three different conditions: ACM fixed, ACM free to move and ACM flung towards impactor. The wheel speed sensors were emulated with the same 7/14 mA pulses such that the vehicle was simulated to be moving with a ramping up and down speed during the impact. This was done such that the EDR data has vehicle speed in both its pre and post crash data. The Bosch Crash Data Retrieval (CDR) tool was used to download the EDR data. Data from these experiments is shown and discussed. Data from the CAN bus has been shown to be a very useful source of information [1, 2] from the OBD II port by requesting the specific PID's. More recent…