The influence of Vehicle Dynamics Control System on the Occupant’s Dynamic response during a Vehicle collision

This paper aims to apply a vehicle dynamics control system to mitigate a vehicle collision and to study the effects of this systems on the kinematic behaviour of the vehicle's occupant. A unique three-degree-of-freedom vehicle dynamics-crash mathematical model and a simplified lumped-mass occupant model are developed. The first model is used to define the vehicle body's crash parameters and it integrates a vehicle dynamics model with a model of the vehicle's front-end structure. In this model, the anti-lock braking system and the active suspension control system are co-simulated, and the associated equations of motion are developed. The second model aims to predict the effect of the vehicle dynamics control system on the kinematics of the occupant. The Lagrange equations are used to solve that model owing to the complexity of the obtained equations of motion. It is shown from the numerical simulations that the vehicle dynamics-crash response and occupant behaviour can be captured and analysed quickly and accurately. Furthermore, it is shown that the vehicle dynamics control system can affect the crash characteristics positively and that the occupant's behaviour is improved

Vehicle Dynamics Control for Rollover Prevention

Vehicle rollover accidents are a particularly dangerous form of road accident. Existing vehicle dynamics controllers primarily deal with yaw stability, and are of limited use for dealing with problems of roll instability. This thesis deals with the development of a new type of vehicle dynamics control system, capable of preventing rollover accidents caused by extreme maneuvering. A control strategy based on limitation of the roll angle while following a yaw rate reference is presented. Methods for rollover detection are investigated. A new computationally–efficient control allocation strategy based on convex optimization is used to map the controller commands to the individual braking forces, taking into account actuator constraints. Simulations show that the strategy is capable of preventing rollover of a commercial van during various standard test maneuvers

Model-Based Vehicle Dynamics Control for Active Safety

The functionality of modern automotive vehicles is becoming increasingly dependent on control systems. Active safety is an area in which control systems play a pivotal role. Currently, rule-based control algorithms are widespread throughout the automotive industry. In order to improve performance and reduce development time, model-based methods may be employed. The primary contribution of this thesis is the development of a vehicle dynamics controller for rollover mitigation. A central part of this work has been the investigation of control allocation methods, which are used to transform high-level controller commands to actuator inputs in the presence of numerous constraints. Quadratic programming is used to solve a static optimization problem in each sample. An investigation of the numerical methods used to solve such problems was carried out, leading to the development of a modified active set algorithm.Vehicle dynamics control systems typically require input from a number of supporting systems, including observers and estimation algorithms. A key parameter for virtually all VDC systems is the friction coefficient. Model-based friction estimation based on the physically-derived brush model is investigated

Actuator Comparison and Coordination for Integrated Vehicle Dynamics Control

The purpose of this Master's Thesis was to compare and coordinate active chassis systems in a search for new ways of controlling two driving situations; side wind exposure and split friction braking. These situations were to be mastered by three active systems; active steering, brakes and suspension. Examples of how to use the systems were presented for each driving situation. The results from the investigation were then used when designing controllers for the applications. Matlab/Simulink was the key tool for evaluation of the control strategies but tests were also carried out in a real vehicle

Integrated vehicle dynamics control using active steering, driveline and braking

This thesis investigates the principle of integrated vehicle dynamics control through proposing a new control configuration to coordinate active steering subsystems and dynamic stability control (DSC) subsystems. The active steering subsystems include Active Front Steering (AFS) and Active Rear Steering (ARS); the dynamic stability control subsystems include driveline based, brake based and driveline plus brake based DSC subsystems. A nonlinear vehicle handling model is developed for this study, incorporating the load transfer effects and nonlinear tyre characteristics. This model consists of 8 degrees of freedom that include longitudinal, lateral and yaw motions of the vehicle and body roll motion relative to the chassis about the roll axis as well as the rotational dynamics of four wheels. The lateral vehicle dynamics are analysed for the entire handling region and two distinct control objectives are defined, i.e. steerability and stability which correspond to yaw rate tracking and sideslip motion bounding, respectively. Active steering subsystem controllers and dynamic stability subsystem controller are designed by using the Sliding Mode Control (SMC) technique and phase-plane method, respectively. The former is used as the steerability controller to track the reference yaw rate and the latter serves as the stability controller to bound the sideslip motion of the vehicle. Both stand-alone controllers are evaluated over a range of different handling regimes. The stand-alone steerability controllers are found to be very effective in improving vehicle steering response up to the handling limit and the stand-alone stability controller is found to be capable of performing the task of maintaining vehicle stability at the operating points where the active steering subsystems cannot. Based on the two independently developed stand-alone controllers, a novel rule based integration scheme for AFS and driveline plus brake based DSC is proposed to optimise the overall vehicle performance by minimising interactions between the two subsystems and extending functionalities of individual subsystems. The proposed integrated control system is assessed by comparing it to corresponding combined control. Through the simulation work conducted under critical driving conditions, the proposed integrated control system is found to lead to a trade-off between stability and limit steerability, improved vehicle stability and reduced influence on the longitudinal vehicle dynamics

The Twin-in-the-Loop approach for vehicle dynamics control

In vehicle dynamics control, engineering a suitable regulator is a long and costly process. The starting point is usually the design of a nominal controller based on a simple control-oriented model and its testing on a full-fledged simulator. Then, many driving hours are required during the End-of-Line (EoL) tuning phase to calibrate the controller for the physical vehicle. Given the recent technological advances, in this paper we consider the pioneering perspective where the simulator can be run on-board in the electronic control unit, so as to calculate the nominal control action in real-time. In this way, it can be shown that, in the EoL phase, we only need to tune a simple compensator of the mismatch between the expected and the measured outputs. The resulting approach not only exploits the already available simulator and nominal controller and significantly simplifies the design process, but also outperforms the state-of-the-art in terms of tracking accuracy and robustness within a challenging active braking control case study

How “International” Should a Third Conflicts Restatement Be in Tort and Contract?

The main goal of this work is to gain knowledge of how and to what extent state-of-the-artsimulation tools can be used in a conceptual development phase for vehicle dynamics control atVolvo Car Corporation (VCC).The first part of the thesis deals with an evaluation of vehicle dynamics simulation tools and theiruses. The three simulation tools selected for the study, namely Mechanical Simulation CarSim 8.2.1,IPG CarMaker 4.0.5, and VI-Grade CarRealTime V14, are briefly described and discussed. In order toevaluate and compare these tools with respect to application for vehicle dynamics control, a criterialist is developed covering aspects such as tool requirements and intended usage. Based on thecriteria list and certain identified drawbacks, a ranking of the tools is made possible. Furthermore,the process of developing vehicle models for the different tools is discussed in detail, along with theprocedure of validating the vehicle models.In the second part, the concept of Collision Avoidance Driver Assistance (CADA) function isintroduced and possible approaches for developing CADA functions are discussed in brief. It isimportant to note that the CADA functions in this work are based on cornering the vehicle i.e.maneuvering around the threat, rather than solely reducing vehicle speed. A number ofimplementations of the functions are developed in Simulink. A frequency analysis of a simplifiedlinear vehicle model is performed to investigate the influence of steering, differential braking, andtheir combination on the resultant lateral displacement of the vehicle during an evasive maneuver.The developed CADA functions are then simulated using the vehicle simulation tools. Two specificmetrics - Lateral Displacement gain and DeltaX - are formulated to evaluate the effectiveness of theCADA functions. Based on these metrics, the assistance obtained due to the functions for a specificevasive maneuver is compared.From the evaluation process of the three tools, two were considered suitable for the purpose ofsimulating collision avoidance functions. The evaluation of the CADA functions demonstrates thatcombined assistive steering with differential braking provides considerable assistance in order toavoid collisions. The simulation results also present interesting trends which provide a usefuldirection regarding the conditions for intervention by such collision avoidance functions during anevasive maneuver. The use of simulation tools makes it possible to observe these trends and utilizethem in the development process of the functions

A Hardware-in-the-Loop Facility for Integrated Vehicle Dynamics Control System Design and Validation

Due to the increased number and the complexity of the embedded systems in today’s vehicle, there is ever increasing pressure to reduce the development cost and time to market of such systems. In recent years, Model based Development (MBD) is becoming a main stream in the development of automotive embedded systems, and Hardware-in-the-Loop (HiL) testing is one of the key steps toward the implementation of MBD approach. This paper presents the recent HiL facility that has been developed at Cranfield University. The HiL setup includes real steering and brake smart actuator, high fidelity validated vehicle model, complete rapid control prototyping tool chain, and driver-in-the-loop capability. The applications of HiL setup are including but not limited to: smart actuators system identification; rapid control development and early validation of standalone and/or integrated vehicle dynamics control systems. Furthermore, the facility can be employed for investigation on driver-vehicle interaction at the presence of standalone active steering and/or brake systems as well as various Advanced Driver Assist Systems (ADAS), such as lane keeping or adaptive cruise control systems. The capability of the HiL facility for validation of a several newly developed vehicle dynamics control systems is presente