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Control-Oriented Modeling of a Vehicle Drivetrain for Shuffle and Clunk Mitigation

Ford Research & Advanced Engineering-Maruthi Ravichandran, Mary Farmer, Jeff Doering
Michigan Technological University-Prithvi Reddy, Kaushal Darokar, Darrell Robinette, Mahdi Shahbakhti, Jason Blough
  • Technical Paper
  • 2019-01-0345
To be published on 2019-04-02 by SAE International in United States
Flexibility and backlash of vehicle drivelines typically cause unwanted oscillations and noise, known as shuffle and clunk, during tip-in and tip-out events. Computationally efficient and accurate driveline models are necessary for the design and evaluation of torque shaping strategies to mitigate this shuffle and clunk. To accomplish these goals, this paper develops two control-oriented models, i.e., a full-order physics-based model and a reduced-order model, which capture the main dynamics that influence the shuffle and clunk phenomena. The full-order model comprises several components, including the engine as a torque generator, backlash elements as discontinuities, and propeller and axle shafts as compliant elements. This model is experimentally validated using the data collected from a Ford truck. The validation results indicate less than 1% error between the model and measured shuffle oscillation frequencies. The reduced-order model is derived by lumping 24 inertia elements into 2 elements, 4 stiffness and damping elements into 2 elements, and 2 backlashes into 1 element. As part of the reduced-order model development, the paper investigates: (i) the effect of lumping transmission and final…
 

Design optimization of Front Hood structure for meeting Pedestrian Headform Protection in existing vehicle

Maruti Suzuki India, Ltd.-Robin Agarwal, Kamlesh Yadav, Rajdeep Singh Khurana
  • Technical Paper
  • 2019-01-0615
To be published on 2019-04-02 by SAE International in United States
Automotive industry today faces the unprecedented challenges both in terms of adapting to changing customer demands in terms of vehicle aesthetics, features or performance as well as meeting the mandatory regulatory requirements, which are being regularly upgraded and becoming stringent day by day. Vehicle hood, being part of vehicle front fascia, needs to fulfill the requirement of vehicle aesthetics as its primary condition. At the same time, every automobile manufacturer has a lineup of older platforms, which are in production and needs to comply with upcoming stricter safety norms, having structure in under hood area designed as per older philosophy, which further reduces the space available for energy absorption. This makes the structure optimization in vehicle hood area much more challenging. Pedestrian protection - an upcoming regulation in India, has seen some major development in recent times. Every automotive manufacturer is looking at ways to make their vehicles regulatory compliant at minimal cost, owing to the cost-conscious dynamics prevalent in Indian market. This paper outlines the case study for meeting the Headform compliance for an…
 

Real-time Motion Segmentation of LiDAR Point Detection for Automated Vehicles

Hanyang University-Chansoo Kim, Sungjin Cho, Sumyeong Lee, Myoungho Sunwoo
Konkuk University-Kichun Jo
  • Technical Paper
  • 2019-01-0688
To be published on 2019-04-02 by SAE International in United States
A Light Detection And Ranging (LiDAR) is now becoming an essential sensor for an autonomous vehicle. The LiDAR provides the surrounding environment information of the vehicle in the form of a point cloud. A decision-making system of the autonomous car is able to determine a safe and comfort maneuver by utilizing the detected LiDAR point cloud. The LiDAR points on the cloud are classified as dynamic or static states depending on the movement of the object being measured. If the movement states of detected points can be provided by LiDAR, the decision-making system is able to plan the appropriate motion of the autonomous vehicle according to the movement of the object. This paper proposes a real-time process to segment the motion states of LiDAR points. The basic principle of the segmentation algorithm is to classify the movement of a current LiDAR point cloud through the previously-measured point clouds, the previous vehicle poses, and a LiDAR extrinsic calibration parameter. First, we set a time window with the fixed size of the buffers and store the previous…
 

Effects of the Wet Retroreflectivity and Luminance of Pavement Markings on Lane Departure Warning in Nighttime Continuous Rain with and without Glare Sources

3M-Susannah Clear, Thomas Hedblom, Jordan Whitney
Texas A&M Transportation Institute-Adam Pike, Timothy Barrette
  • Technical Paper
  • 2019-01-1014
To be published on 2019-04-02 by SAE International in United States
A common challenge for both machine vision (MV) systems based on visible-spectrum cameras and for human drivers is detection of pavement markings in nighttime rainy conditions. This occurs because a layer of water refracts the light differently than air, causing conventional markings to substantially retroreflect the light away from the driver or camera when the marking is immersed. This reduces the marking retroreflectivity in wet conditions, and thus the contrast in the image collected by the camera at longer viewing distances. MV lane departure warning (LDW) systems also depend on pixel data from shorter viewing distances; the contrast here also depends on the luminance (Cap Y (CIE)) of the marking, which typically is reduced if the marking is soiled or worn. The efficacy of LDW systems are also known to be influenced by the presence of glare, as regions of glare test the limits of the high dynamic range of the sensor and reduces the contrast between the marking and the surrounding roadway surface. In this study, the authors explored the effects of wet retroreflectivity…
 

Numerical Analysis using Fast RANS simulations and Comparison with Experimental Measurements for Closed and Open Grille Realistic Car Models

Simerics Inc.-Sujan Dhar, Yu Jiang
  • Technical Paper
  • 2019-01-0655
To be published on 2019-04-02 by SAE International in United States
Over the past few years, the DrivAer car geometry has driven development of simulation methodology for vehicle aerodynamics. Due to the realistic geometry of the DrivAer car model the results obtained from simulations can be easily extended to the aerodynamic design process of production vehicles. This paper details a comprehensive CFD study of all three variants of the DrivAer car geometries: Fastback, Notchback and Estate configurations. The most realistic geometry was chosen for each of the variants; with detailed underbody, wheels and mirrors. In addition to the closed-grille standard DrivAer models, the open–grille variant has also been simulated. Simulations are performed both with and without ground simulation. Mesh generation was performed without surface alterations (e.g. wrapping) using a novel Binary-Tree automatic unstructured mesher. All simulations were performed using RANS turbulence model. A consistent modeling methodology was developed that was rigorously applied to all variants of the DrivAer model and the simulations are shown to have consistently good agreement with experimental measurements. This demonstrates the potential of using such a methodology for several different types of…
 

Development of Parametric Tool to Design Base Frame for Marine Application Engine

Cummins Inc.-Mukesh Kumar, Neeraja Rajasekhar, Prachi Pokharkar, Bibhu Mahanta, Rohit Saha
  • Technical Paper
  • 2019-01-0798
To be published on 2019-04-02 by SAE International in United States
A spread sheet based parametric tool is developed to design the base frame for a marine genset. Factors such as engine details, alternator details, anti-vibration mount (AVM) etc., that determine the design of the base frame, are set as parameters in the spreadsheet. The spreadsheet has formulae to calculate channel specifications, and anti-vibration mount deflections. It is linked to channel standards database and selects the optimal channel based on calculations. Similarly, the tool provides guidance in selection of anti-vibration mounts (AVM) from supplier catalogues, helps to predict number of anti-vibration mounts required and their location on base frame. This spread sheet is integrated with a generic base frame 3D model and 2 D print in Creo, which is auto-updated based on calculated parameters in the spreadsheet. Using this tool the user can generate a 3D-model and 2D print. This tool helps to standardize the design process and reduces design turnaround time considerably. The output of the tool and existing base frame designs were analysed using a finite element tool (ANSYS). Modal and static analysis were…
 

A Systems Approach in Developing a Ultralightweight Outside Mounted Rearview Mirror Using Discontinuous Fiber Reinforced Thermoplastics

Clemson University-Sai Aditya Pradeep, Srikanth Pilla
Clemson University - ICAR-Senthil Raj Ramesh, Veera Aditya Yerra
  • Technical Paper
  • 2019-01-1124
To be published on 2019-04-02 by SAE International in United States
Fuel efficiency improvement of automobiles has been a topic of great interest in the past years, especially with the introduction of new CAFE standards. Although there are multiple ways of improving the fuel efficiency of an automobile, light weighting is one of the most common approaches taken by many automotive manufacturers. Importance of lightweighting is more significant in electric vehicles as it directly effects the range. The use of composite materials in place of metals has proven to achieve substantial weight reductions in the past. The focus of using these composite materials for weight reduction was generally limited to major structural components such as BiW and closures, due to the high material cost. Secondary structural components which contribute approximately 30% of the vehicle weight are usually neglected by these weight reduction studies. This work is an attempt to prove that composites can also be used effectively in the weight reduction of secondary structural components while meeting the mechanical performance, cost and scalability. Discontinuous fiber reinforced injection molded materials offer good mechanical properties and very high…
 

Laser Light-Based Technique for Detection and Assessment of Localized Defects in Reflective Automotive Surfaces

Western University-Navraj S. Heer, O. Remus Tutunea-Fatan, Jeffrey T. Wood
  • Technical Paper
  • 2019-01-1266
To be published on 2019-04-02 by SAE International in United States
Surface quality plays an important role on aesthetic appeal of any exterior component of a vehicle. As such, smooth and defect-free are some of the critical characteristics of an automotive surface. Numerous manufacturing-related factors such as production environment, substrate material, coating material, handling are known to generate defects to inherently decrease the overall quality of the external surface. Many of these defects tend to be localized while spreading over large areas of the surface. However, the vast majority of available systems are unable to unequivocally quantify surface defects and in most cases, the surface quality assessment is performed in a relative and rather qualitative manner. To address this, the main goal of the present study was to develop a new laser light-based technique capable to detect and quantify the localized defects that are present on the surface of reflective components for automotive exteriors. For this purpose, the setup of the proposed prototypical system was validated through a blend of optical simulations and experiments performed on concave and convex defects with determined geometries and with sizes…
 

Aerodynamically Induced Loads on Hood Latch and Hood Retention Systems

General Motors-James Nelsen, Ali Seyam
  • Technical Paper
  • 2019-01-0657
To be published on 2019-04-02 by SAE International in United States
Hood Latch Systems are regulated to have a secondary latch or secondary latching position, in order to retain the hood in case of partial or incomplete closure by the operator while driving the vehicle. On a vehicle with a front-opening hood, an incompletely closed hood can be lifted by incoming air flow and cause a 'hood fly-up' condition where the hood obscures the driver's vision and could lead to a higher risk of loss of vehicle control or forward collision. Many vehicles are equipped with hood ajar switches that will provide a warning to the driver if the hood is not latched, however most of these systems require some hood displacement from the full latch condition in order to provide a signal to the vehicle's driver. There have been instances documented of a "false latch" conditions whereby the latch appears to be fully closed based on apparent hood flushness to the body, however the latch was not fully engaged and the hood was prevented from moving to the pop-up or secondary latch position due to…
 

A Mathematical Analysis of Off-Road Vehicle to Avoid “Hang Up” and “Nose In” Failures

Georgia Southern University-Aniruddha Mitra, Keith Russell
  • Technical Paper
  • 2019-01-0394
To be published on 2019-04-02 by SAE International in United States
Aniruddha Mitra Professor of Mechanical Engineering, Georgia Southern University Keith Russell Undergraduate Student, Mechanical Engineering Department, Georgia Southern University This study focuses on the design of off-road vehicles to avoid “Hang Up” and “Nose In” failures with specific case study of Georgia Southern University’s SAE mini BAJA vehicle. The BAJA vehicle may encounter two distinct kinds of failure while climbing or descending terrain obstacles: “Hang Up” failure, and “Nose In” failures. Hang up failure occurs when the bottom of the chassis of the vehicle makes contact with the obstacle. This occurs after the front tires have cleared the obstacle but before the rear tires have. This mitigates the pace of the vehicle and may cause damage. Nose in failure is when the protruding front bumper or “nose” of the vehicle makes direct contact with either the ground or the obstacle. The possible ramifications of this event are much more disastrous than the Hang up failure. Nose in failure can send the vehicle into an end over end flip, or cause significant structural damage to the…