Vehicle Dynamics

One of the major costs incurred by railway companies is the maintenance of turnouts.This situation occurs because the large dynamic forces between the wheels of a train and the rails of a turnout cause excessive wear, rolling contact fatigue and rapid degradation of other components. A thorough understanding of the dynamic interaction between a train and a turnout could lead to a better design of the corresponding vehicle/track or of the damage mechanisms and subsequently to a smarter maintenance planning. Such an insight can be obtained through a detailed model of the train-turnout interaction. Such models exist in the literature for vehicle-track interaction, but they have some shortcomings when it comes to train-turnout interaction. This leads to the following research questions: 1. How to model the wheel rail contact? In this thesis different models are presented for the search of the contact location as well as for the normal and the tangential contact problem. Especially the r...

This paper examines the directional handling characteristics of several vehicles in their original condition, then examines modifications to a few of these vehicles to determine if the handling characteristics can be made more forgiving of normal operators without sacrificing utility and without substantial increases in cost. These analyses of vehicles are made in the context of what normal operators are capable of performing with regards to steering response.

This paper proposes a new H∞ yaw-moment control scheme using brake torque for improving vehicle performance and stability especially in high speed driving. Its characteristics is that only one brake is used for control depending on the vehicle state. Steering angles are modeled as a disturbance input to the system and the controller minimizes the difference between the performance of

The Florida Department of Transportation (DOT) has initiated multi-modal level-of-service (LOS) methodologies, including that for the bicycle travel mode. It has already adopted a bicycle LOS methodology for the roadway segment portion of the transportation network, the Bicycle Level of Service Model. Florida DOT’s ultimate goal is to develop corridor- and facilities-level LOS methodologies. Toward that goal, Florida DOT sponsored research to develop the first part of an intersection bicycle LOS methodology, the Intersection LOS for the bicycle through movement. This Intersection LOS for the bicycle through movement would provide a measure of the level of safety and comfort experienced by bicyclists riding through an intersection. The Intersection LOS model for the bicycle through movement is based on Pearson correlation analyses and stepwise regression modeling of approximately 1,000 combined real-time perceptions from bicyclists traveling a course through a typical U.S. metropolit...

A NPID (nonlinear PID) control algorithm is applied to a class of truck ABS (anti-lock brake system) problems. The NPID algorithm combines the advantages of robust control and easy tuning. Simulation results at various situations using TruckSim show that NPID controller has shorter stopping distance and better velocity performance than the conventional PID controller and a loop-shaping controller

This paper presents a novel automatic and dynamic camera calibration algorithm based on traffic visual surveillance. The algorithm can automatically calibrate the intrinsic and extrinsic parameters of camera, and offer enough guarantee to extract traffic real-time parameters. This paper firstly indicates the significance of applying automatic and dynamic calibration algorithm to intelligent transportation system, then establishes a mathematical model of calibration parameters between camera image and actual road. The algorithm is established from three view points, which are description, flow chart and algorithm description. Afterward this paper describes the experimental method and result based on this novel algorithm. Finally this paper indicates wide application foreground of this algorithm in intelligent transportation system.

Unmanned underwater vehicles (UUVs) have become an integral part in helping humans do underwater explorations more efficiently and safely since these vehicles can stay underwater much longer than any human can possibly do and they require little or almost no human interaction. These vehicles are subject to dynamic and unpredictable nature of the underwater environment resulting to complexities in their navigation. This paper proposes a fuzzy logic-based controller to allow the vehicle to navigate autonomously while avoiding obstacles. The said controller is implemented in an actual low-cost underwater vehicle equipped with magnetometer and ultrasonic sensors. The intelligence of the UUV includes a two fuzzy logic block, namely Motion Control block and Heading Correction block. The fuzzy logic controller takes in target positions in X, Y and Z axes. Also, the heading error and rate of heading error are included as inputs in order to correct the bearing or direction of the vehicle. A ...

A mathematical model describing the dynamic characteristics of the vehicle needs to be solved for predicting the future position and orientation of vehicle relative to the changing environment. By reducing the time consumed to solve the complex model, the cycle time for the overall process can be decreased. The work done in this paper, attempts to reduce the computational time by mathematically finding the redundant elements, which do not add to the major dynamics of the system but increase the calculation time by increasing the system complexity. Here, in this paper, eigenvalue separation and eigenvalue sensitivity methods have been applied to the different bond graph models of bicycle vehicle with suspension system, antilock braking system, steering system and four wheel vehicle models. The reduced system behaviour is similar to the response from the actual bond graph model. This method is applicable to linear systems as well as for the non-linear systems after certain modifications.

In vehicle dynamics, the determination of the tire-road interaction forces plays a fundamental role in the analysis of vehicle behavior. This paper proposes a simple yet effective approach to estimate longitudinal forces. The proposed approach: i) is based on equilibrium equations; ii) analyses the peculiarities of driving and braking phases; iii) takes into account the interactions between vehicle sprung mass and unsprung mass. The unsprung mass is often neglected but that might lead to significant approximations, which are deemed unacceptable in performance or motorsport environments. The effectiveness of the proposed approach is assessed using experimental data obtained from a high performance racing car. Results show that the proposed approach estimates tire longitudinal forces with differences up to 10% when compared against a simpler formulation which uses only the overall mass of the vehicle. Therefore the distinction among vehicle sprung and unsprung masses, which is likely to be an easily obtainable piece of information in motorsport environments, is exploited in this approach to provide significant benefits in terms of longitudinal force estimation , ultimately aimed at maximizing vehicle performance.

Tractive force and train movement stability dependence on division of forces involved in wheel/rail contact area are the main subjects of this article. The influence of wheel/rail contact properties in the vehicle dynamics and adhesion fields is investigated. Current tendency all over the world is to reduce the conicity of wheels with the aim of increasing the speed of trains. Wave-length of moving wheel-set in track for worn wheel-set tyre is twice less than for new wheel running profile.

Car cabin interior vehicle acoustical comfort is one of the factors which attract the buyers to purchase the vehicle in order to have comfort sound and minimum noise in passenger car cabin. Basically the amount of discomfort depends to magnitude, frequency, direction and also the duration of exposed vibration in the cabin. The comfort of the driving influences driving performance. Generally the vibration is caused by two main sources: engine transmission and interaction between tyre and road surface. In this study the effects of tyre to vehicle acoustical comfort were investigated. A vehicle acoustical comfort index (VACI) was used to evaluate the effect of tyre to vehicle acoustical comfort. By substituting the sound quality (loudness, sharpness, roughness, and fluctuation strength) which were influenced by the vibration due to interaction between tyre and road surface, both of the VACI values (stationary and moving) can be obtained, and the difference between both values can be considered as the effect of the tyre. The sound quality study has focused on the estimation of the noise quality changes through the trends pattern based on the generated sound quality which relates to engine speeds. From the results, the amounts of sound quality changes with the increase of the engine speeds, except for both of fluctuation strength and sharpness parameters. The results of the study provide one method to predict the amounts of the VACI values caused by the effect of the tyre and the interaction between tyre and road surface.

Industrial Overview:
As a basic theory of the vehicle industry, vehicle dynamics play an important role in the development of the vehicle industry. In the past decades, great progress was made in the theory and experiment of vehicle dynamics. Vehicle Dynamics gives us an idea of how a vehicle will respond to various situations. This study has its roots in the work of creative engineers who established the methodology of various dynamic systems. As automobiles evolved the understanding of vehicle dynamics became important. Subsequently, it has moved towards modeling, analysis, and optimization of multi-body dynamics with accurate positioning, sensing, and calculations with intelligent computer software.

A clear understanding of Vehicle Dynamics is needed for predicting the behavior of any vehicle under different conditions. Responses of components and intuitive feedback to driver governs safety and handling in general. Also, the dynamics of a vehicle can be the deciding factor in any competitive event. In-vehicle dynamics, the vehicle body (sprung mass), the suspension component (spring and damper) and tire (unsprung mass) are essential parts of the system.

Program Objective:
The modeling approaches and characteristics of the vehicle, tire and driver model with the respect to handling and driving dynamics are summarized in the program. The important research issues about the vehicle-pavement coupled dynamics are discussed in detail. Several problems and directions for further studying in vehicle dynamics are pointed out. Understand the fundamentals of vehicle dynamics and suspension/steering design. Gain practical knowledge of how the vehicle moves and how the suspension and steering behaves. Also, gain hands-on experience over simulation software of vehicle dynamics and suspension design.

DIYguru presents a Nano-degree program on Vehicle Dynamics. This program provides you with the most flexible learning environment possible. This program is offered as a self-paced program often referred to as an asynchronous online program which is time-independent, meaning that it can be accessed 24X7 within the tenure of 90 days. This program can be accessed from multiple devices which makes it easy to learn on the go.

Lectures that are pre-recorded or slide presentation with voice-over commentary, interactive discussion boxes that foster student to student interaction, Email communication with the instructor are part of this process. Downloadable educational tools such as e-books, research papers, and government reports are made available at just one click.

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What are the learning outcomes?
Apply knowledge of mathematics, science, and engineering.
Design and conduct experiments, as well as to analyze and interpret data.
Function on multi-disciplinary teams.
Identify, formulates, and solves engineering problems.
Recognition of the need for, and an ability to engage in life-long learning.
Utilize experimental, statistical and computational methods and tools necessary for engineering practice.
To develop extensive knowledge and understanding of a wide range of computer modeling and simulation software.
Conduct rigorous and ethical research / formal enquiry into related issues that require familiarity with a range of research sources and appropriate methodologies.
What are the main highlights of the program?
Learn without a career break with online classes available 24*7.
One can access the course at their own pace, but with the investment of 3-5 hours/week, it can be finished within a month.
The program uses a Continuous Evaluation System that assesses the learners over convenient and regular intervals. Such a system provides timely and frequent feedback and helps busy working professionals stay on course with the program.
The education delivery method is a blend of classroom and experiential learning.
Participants who will complete the program become eligible for Mentorship and Placement help through our Job Fairs.
This program is focused on student-level competitions like SAE BAJA, SAE SUPRA, and even Formula Bharat and Formula-E.

Suspension system is one of the challenging portions in designing a vehicle. The
complete stability of the vehicle under dynamic conditions depends on the suspension system of
the vehicle. Suspension system of a vehicle is interlinked with other systems such as steering,
Wheels and Brakes. The main objective of this document is to provide complete guidance in
designing and calculation of an independent suspension system with double control arms. The
required parameters are calculated on considering a prototype vehicle with gross weight of 350 kg
such as required stiffness of shock absorbers, Ride frequency, Motion ratio, Coefficient of
damping etc. A CADD model was made with CATIA v5 r20 and SOLIDWORKS on the basis of
calculations obtained and stress analysis was carried out for this model in various software such
as Ansys. The complete assembled model was tested in LOTUS Shark and the result was obtained.

Paper presents an innovative method for finding the best setup of: race driver actions, vehicle motion trajectory, and vehicle chassis parameters for a closed-loop maneuver. Formulated " miMa " simulation model of driver-vehicle-road system with 26 generalized coordinates and more than 400 parameters is implemented for optimization with genetic algorithms. Numerical example considers Ford Focus ST170 (FWD) prepared for a track racing, which is negotiating a selected track part with RH corner. The combined optimization includes 28 decision variables. Two criteria, i.e. section time and exit velocity, are defined as optimization goals. Different strategies for improving performance of FWD car are found by using optimization.

in recent years, fatigue is a prominent failure mechanism for any vehicle's frame structure, and can lead to serious accidents, costly recalls, and poor product image for the vehicle's frame manufacturers. This paper deals with investigation of the fatigue behavior of the vehicle's frame and has carried out a design and modal analysis in SolidWorks. In this study, mode shapes and their natural frequencies of the wheel are obtained from the simulations. A method has been proposed to optimize the wheels and frame's material and design for an improved fatigue resistance.

The Autonomous Systems Laboratory is in the midst of developing an advanced underwater robotic technology test platform. The platform consists of the Omni-Directional Intelligent Navigator (ODIN) and the Integrated Graphic Workstation (IGW). ODIN is a six degree-of-freedom (dof) underwater vehicle with dual operational modes (autonomous and tethered) and a single dof mechanical manipulator. IGW is a real-time, 3-dimensional graphic monitoring, testing, and evaluation workstation. This paper presents ODIN's mechanical and electrical specifications; its vehicle dynamics and depth control system; its recent simulation and experimental results; and IGW's specifications

This study aimed to develop and apply a method to acquire the values of the developed mechanical stress on the steering system of a BAJA SAE prototype vehicle.  For its development, tests were made on the 2012 Parahybaja Team prototype. The prototype have been representing the Federal University of Campina Grande in competitions organized by SAE Brazil between 2012 and 2014. The objective of this work is to obtain values of the mechanical forces, which are transmitted to the tie rod of the steering assembly, using strain gauges for measurement of strain on the part. The motivation for the development of this work is the needing of improvements in the steering system knowing the extreme force values that acts on it. The used methodology has started with the analysis of the possibilities of obtaining the desired data, followed by the selection of the strain gage sensors and its data logger.  The needed tools and materials have been purchased, the sensors bonded on the part surface and the system calibrated. Then, the system was assembled to the vehicle and the tests were specified. Collecting the values of forces that govern the different kinds of tests for specific situations was the result of this study and it can conclude that its objectives were achieved as the found input data will help the design of a new steering system for the Parahybaja Team.