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 presents a process for the estimation of tire-road forces, vehicle sideslip angle and wheel cornering stiffness. The method uses measurements (yaw rate, longitudinal/lateral accelerations, steering angle and angular wheel velocities) only from sensors which can be integrated or have already been integrated in modern cars. The estimation process is based on two blocks in series: the first block contains a sliding-mode observer whose principal role is to calculate tire-road forces, while in the second block an extended Kalman filter estimates sideslip angle and cornering stiffness. More specifically, this study proposes an adaptive tire-force model that takes variations in road friction into account. The paper also presents a study of convergence for the sliding-mode observer. The estimation process was applied and compared to real experimental data, in particular wheel force measurements. Experimental results show the accuracy and potential of the estimation process.

The principal concerns in driving safety with standard vehicles or cybercars are understanding and preventing risky situations. A close examination of accident data reveals that losing control of the vehicle is the main reason for most car accidents. To help to prevent such accidents, vehicle-control systems may be used, which require certain input data concerning vehicledynamic parameters and vehicle-road interaction. Unfortunately, some fundamental parameters, like tire-road forces and sideslip angle are difficult to measure in a car, for both technical and economic reasons. Therefore, this study presents a dynamic modeling and observation method to estimate these variables. One of the major contributions of this study, with respect to our previous work and to the largest literature in the field of the lateral dynamic estimation, is the fact that lateral tire force at each wheel is discussed in details. To address system nonlinearities and unmodeled dynamics, two observers derived from extended and unscented Kalman filtering techniques are proposed and compared. The estimation process method is based on the dynamic response of a vehicle instrumented with available and potentially integrable sensors. Performances are tested using an experimental car. Experimental results demonstrate the ability of this approach to provide accurate estimations, and show its practical potential as a low-cost solution for calculating lateral tire forces and sideslip angle.

In this paper, we compare three observers and methods for estimation of the longitudinal and latéral velocity of the vehicle. These methods are based on the First Order Sliding Mode (FOSM), Second Order Sliding Mode (SOSM) and on the use of algebraic approach ALIEN. Their performance are studied using a 16 DoF dynamic simulator.

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 smooth-primitive constrained-optimization-based path-tracking algorithm for mobile robots that compensates for rough terrain, predictable vehicle dynamics, and vehicle mobility constraints has been developed, implemented, and tested on the DARPA LAGR platform. Traditional methods for the geometric path following control problem involve trying to meet position constraints at fixed or velocity dependent look-ahead distances using arcs. We have reformulated the problem as an optimal control problem, using a trajectory generator that can meet arbitrary boundary state constraints. The goal state along the target path is determined dynamically by minimizing a utility function based on corrective trajectory feasibility and cross-track error. A set of field tests compared the proposed method to an implementation of the pure pursuit algorithm and showed that the smooth corrective trajectory constrained optimization approach exhibited higher performance than pure pursuit by achieving rough four times lower average cross-track error and two times lower heading error.

Many dynamic simulators have been developed in the last thirty years for different types of vehicles. Flight simulators and drive simulators are very well known examples. This paper describes the design and implementation of a dynamic simulator for the testing of inertial sensors devoted to vehicle navigation through a Hardware-In-The-Loop test rig composed of an industrial robot and a commercially available Inertial Measurement Unit (IMU). The authors are developing an innovative localization algorithm for railway vehicles which integrates inertial sensors with tachometers. The opportunity to set up a testing simulator capable of replicating in a realistic fashion the dynamic effects of the vehicle motion on inertial sensors allows to avoid expensive on board acquisitions and to speed up algorithm tuning. The real-time control architecture featured by the available industrial robot allows to precisely specify and execute motion trajectories with tight path and time law constraints required by the application at hand.

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

A comprehensive study of the eVects of acceleration and braking on motorcycle stability is presented. This work is based on a modi®ed version of a dynamic model presented earlier, and is thought to be the most comprehensive motorcycle dynamic model in the public domain. Extensive use is made of both non-linear and linearized models. The models are written in LISP and make use of the multibody modelling package AUTOSIM. There is novelty in the way in which control systems have been used to control the motorcycle drive and braking systems in order that the machine maintains desired rates of acceleration and deceleration. The results show that the wobble mode of a motorcycle is signi®cantly destabilized when the machine is descending an incline or braking on a level surface. Conversely, the damping of the wobble mode is substantially increased when the machine is ascending an incline at constant speed, or accelerating on a level surface. This probably accounts for the pleasingly stable`feel' of the machine under ®rm acceleration. Except at very low speeds, inclines, acceleration and deceleration appear to have little eVect on the damping or frequency of the weave mode. Non-linear simulations have quanti®ed the known di culties to do with rear tyre adhesion in heavy braking situations that are dominated by rear wheel braking.

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.

Reducing weight while maintaining structural integrity is one of the key challenges Formula SAE teams face as they try and design the suspension of the formula car. The purpose of this paper is to present experimental data on designing and optimizing a carbon fiber suspension system for formula cars. The reason carbon fiber suspensions are favored over the current steel suspensions is because of they can reduce the weight of the suspension by 50%. Pull tests on an Instron machine were performed on over 15 specimens composed of a carbon fiber tube with an aluminum insert bonded to each end. Loctite E-120HP epoxy was used and the surface preparation, bond gap, and bond length were varied to find the optimal bond strength. An average bond strength of 2,382.6 pounds per square inch was determined for specimens with surface preparation. Furthermore a bond gap of 0.0065 to 0.008 inches was found to give the strongest bond.

Improvement in braking performance and vehicle stability can be achieved through the use of braking systems whose brake force distribution is variable. Electronic braking force distribution has an important and serious role in the vehicle stopping distance and stability. In this paper a new approach will be presented to achieve the braking force distribution strategy for articulated vehicles. For this purpose, the mathematical optimization process has been implemented. This strategy, defined as an innovative braking force distribution strategy, is based on the wheel slips. The simulation results illustrate proposed strategy can significantly improve the vehicle stability in curved braking for different levels of vehicle deceleration.

The objective of this paper is to compare the performance of a new proposed Measurement Assisted Partial Re-sampling (MAPR) filter against the performance of the Extended Kalman filter and the Mixture Monte Carlo Localizer within the context of a navigation algorithm for a dynamic 6 DoF system. In this paper, an autonomous underwater vehicle (AUV) is used as the dynamic system. The performances of the above three filters in resolving a navigation solution are assessed by giving the AUV a sequence of trajectories that highlight the sensitivities of the navigation algorithm to noise. This paper demonstrates that the MAPR filter is capable of computing an estimate that, like the EKF, takes into account the dynamics of the system, but like all particle filters is also capable of estimating non-Gaussian distributions.

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 ...

Vehicular ad hoc networks (VANETs) are going to be an important communication infrastructure in our life. Because of high mobility and frequent link disconnection, it becomes quite challenging to establish a robust multi-hop path that helps packet delivery from the source to the destination. This paper presents a multi-hop routing protocol, called MURU, that is able to find robust paths in urban VANETs to achieve high end-to-end packet delivery ratio with low overhead. MURU tries to minimize the probability of path breakage by exploiting mobility information of each vehicle in VANETs. A new metric called expected disconnection degree (EDD) is used to select the most robust path from the source to the destination. MURU is fully distributed and does not incur much overhead, which makes MURU highly scalable for VANETs. The design is sufficiently justified through theoretical analysis and the protocol is evaluated with extensive simulations. Simulation results demonstrate that MURU significantly outperforms existing ad hoc routing protocols in terms of packet delivery ratio, packet delay and control overhead.

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.

This paper investigates the longitudinal wheel slip tracking control approach for ground vehicle. A mathematical model of a quarter vehicle undergoing a straight-line braking maneuver is used as the control model. Second order sliding mode (SOSM) control approach using super-twisting technique is proposed to manipulate the braking torque to control the wheel slip. The effectiveness of the SOSM is compared to the conventional sliding mode in the simulations of emergency straight line braking in Simulink. With the SOSM, the chattering phenomenon is eliminated, giving a smooth tracking trajectory and lower slip error and control effort.

Mobile Adhoc Network (MANET) is a network of a number of mobile routers and associated hosts, organized in a random fashion via wireless links [16]. During recent years MANET has gained enormous amount of attention and has been widely used for not only military purposes but for search-andrescue operations, intelligent transportation system, data collection, virtual classrooms and ubiquitous computing [14]. Service Discovery is one of the most important issues in MANET. It is defined as the process of facilitating service providers to advertise their services in a dynamic way and to allow consumers to discover and access those services in an efficient and scalable manner [20]. In this paper, we are proposing a flexible and efficient approach to service discovery for MANET by extending the work of [5]. Most of the service discovery protocols proposed in literature don't provide an appropriate route from consumer to service provider. Hence after services are discovered, a route request needs to be initiated in order to access the service. In this paper, we are proposing a robust and flexible approach to service discovery for MANET that not only discovers a service provider in the vicinity of a node, but at the same time, it also provides a route to access the service. We have extended the approach proposed in [5] for efficiency by adding the push capabilities to service discovery

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.

Accurate knowledge on the absolute or true speed of a vehicle, if and when available, can be used to enhance advanced vehicle dynamics control systems such as anti-lock brake systems (ABS) and auto-traction systems (ATS) control schemes. Current conventional method uses wheel speed measurements to estimate the speed of the vehicle. As a result, indication of the vehicle speed becomes erroneous and, thus, unreliable when large slips occur between the wheels and terrain. This paper describes a fuzzy rule-based Kalman filtering technique which employs an additional accelerometer to complement the wheel-based speed sensor, and produce an accurate estimation of the true speed of a vehicle. We use the Kalman filters to deal with the noise and uncertainties in the speed and acceleration models, and fuzzy logic to tune the covariances and reset the initialization of the filter according to slip conditions detected and measurement-estimation condition. Experiments were conducted using an actual vehicle to verify the proposed strategy. Application of the fuzzy logic rule-based Kalman filter shows that accurate estimates of the absolute speed can be achieved euen under sagnapcant brakang skzd and traction slip conditions.

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.

He has authored over 35 refereed publications and received two patents. His active research interests include control design and state estimation for nonlinear systems, fault diagnostics, intelligent transportation systems, active noise control, and MEMS sensor design.

This paper presents the development and implementation of a multiprocessor system-on-chip solution for fast and real time simulations of complex and nonlinear wheel-rail contact mechanics. There are two main significances in this paper. Firstly, the wheel-rail contact laws (including Hertz and Fastsim algorithms), which are widely used in the study of railway vehicle dynamics, are restructured for improved suitability that can take advantage of the rapid developing multiprocessor technology. Secondly, the complex algorithms for the contact laws are successfully implemented on a medium-sized FPGA (Field-Programmable-Gate-Array) device using six NiosII processors, where the executions of the Hertz and Fastsim parts are pipelined to achieve further enhancement in doing multiple contacts and the operation scheduling is optimized. In the Fastsim part the floating point units with buffering mechanism are efficiently shared by five processors connected in a token ring topology. The FPGA design shows good flexibility in utilizing logic element and on-chip memory resource on the device and scalability for a significant speed-up on a larger device in future work.

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.

This paper compares four observers (virtual sensors) of vehicle sideslip angle and lateral forces. The first is linear and uses a linear vehicle model. The remaining observers use an extended nonlinear model. The three nonlinear observers are: extended Luenberger observer, extended Kalman filter and sliding-mode observer. Modeling, model simplification, and observers are described, and an observability analysis is performed for the entire vehicle trajectory. The paper also deals with three different sets of sensors to see the impact of observers results. Comparison is first done by simulation on a valid vehicle simulator, and then observers are used on experimental data. Our study shows that observers are more accurate than simple models as regards unmeasurable variables such as sideslip angle and transversal forces. It also shows that speed of center of gravity is not an indispensable variable here.

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

Rollover and jack-knifing of tractor semitrailer on high speed obstacle avoidance under emergency are serious threats for motorists. A tractor semitrailer model was built with multi-rigid-body method in this paper. The steering performance of tractor semitrailer has been analyzed, as well as the stability control theory, including yaw rate following, anti-rollover. The dynamics simulation for yaw rate following and anti-rollover has been performed on the dynamic tractor semitrailer. The results show that the vehicle dynamics control proposed in this paper can stabilize the tractor semitrailer, rollover and jack-knifing are prevented and the tractor semitrailer more accurately follows the driver's desired path.

Interest in control of multiple autonomous vehicles continues to grow for applications such as weather monitoring, geographical mapping fauna surveys, and extra-terrestrial exploration. The task of persistent surveillance is of particular significance in that the target area needs to be continuously surveyed, minimizing the time between visitations to the same region. This distinction from one-time coverage does not allow a straightforward application of most exploration techniques to the problem, though ideas from these methods can still be used. The aerial vehicle dynamic and endurance constraints add additional complexity to the autonomous control problem, whereas stochastic environments and vehicle failures introduce uncertainty. In this work, we investigate techniques for high-level control, that are scalable, reliable, efficient, and robust to problem dynamics. Next, we suggest a modification to the control policy to account for aircraft dynamic constraints. We also devise a health monitoring policy and a control policy modification to improve performance under endurance constraints. The Vehicle Swarm Technology Laboratory-a hardware testbed developed at Boeing Research and Technology, Seattle, WA, for evaluating a swarm of unmanned air vehicles-is then described, and these control policies are tested in a realistic scenario.

In this paper, we study the capacity of cellular systems with interference-adaptation dynamic channel allocation (DCA) through a set of heuristics that evaluate the required number of channels for some mobile traffic pattern. In particular, we evaluate the improvement in the reuse factor given the knowledge of the mobiles' locations. Assuming that the mobiles' locations are sampled from the uniform random distribution or are fixed on a uniform grid, we show the effect of a number of parameters, such as the number of mobiles per cell, the minimum allowable signal-to-interference ratio, and the limited knowledge of mobiles' locations. We also investigate the effect of shadow fading and signal-based power control. Although previous papers have proposed various heuristics with varying performance, here we present heuristics that are shown to give the maximum packing results based on our assumptions. In particular, the single-interferer assumption, used throughout our work, is justified and the optimality of the square-root signalbased power control is proven.

The concept, known as the Canard Rotor/Wing (CRW) unmanned aerial vehicle (UAV) combines the hover flight characteristic of a helicopter with high subsonic cruise of a fixed-wing aircraft. The longitudinal flight dynamic model of CRW was developed, and the trim result was derived in the full flight envelope. The linear model of CRW was derived by the Jacobian linear method, and it was nonlinearly dependent on the time-varying flight speed and altitude. The tensor-product (TP) model transformation was adopted to transform the model to a convex polytopic model form. Hence, a linear parameter-varying (LPV) synthesis method was used to design the flight control system of CRW in the rotary mode. The simulation results show that the desired performance objectives are achieved in the rotary flight stage.

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.

The problem of vehicle yaw control is addressed in this paper using an active differential and yaw rate feedback. A reference generator, designed to improve vehicle handling, provides the desired yaw rate value to be achieved by the closed loop controller. The latter is designed using the second-order sliding mode (SOSM) methodology to guarantee robust stability in front of disturbances and model uncertainties, which are typical of the automotive context. A feedforward control contribution is also employed to enhance the transient system response. The control derivative is constructed as a discontinuous signal, attaining an SOSM on a suitably selected sliding manifold. Thus, the actual control input results in being continuous, as it is needed in the considered context. Simulations performed using a realistic nonlinear model of the considered vehicle show the effectiveness of the proposed approach.