With recent developments in active vehicle drivelines and the trend towards the use of electric propulsion in road vehicles, the optimal way to distribute power in a vehicle has become an interesting area of research. Automobiles with Active Torque Distribution (ATD) capabilities demonstrate improved handling and stability, and there is the possibility that energy consumption could be reduced through better distribution of power. Motorcycles that can apply some of the drive torque at the front wheel exist, with the aim of increasing tractive force on low-friction surfaces. Research is required to investigate the effects of torque distribution on the handling and efficiency of motorcycles and automobiles. In this work, multibody models of both motorcycles and automobiles are created, and are verified with existing mathematical models. The vehicle models include the influences of suspension, aerodynamics and gyroscopic effects, and complex tyre models are used that account for combined lateral and longitudinal slip and the vertical loading situation. Simple driver models are used to control the speed and yaw rate of the vehicles while they undertake a series of on-road manoeuvres. Left–right torque vectoring is shown to be effective in the alteration of the steady-state handling characteristics of the automobile, and front–rear torque vectoring has a small effect at high speeds. A slight increase is possible in transient responsiveness at moderate speeds, but instabilities can be exacerbated at high speeds. In motorcycles, the torque distribution has only a small effect on handling in steady-state situations. During straight-running, the optimum efficiency of the both vehicles is shown to occur when the torque is distributed in proportion with the vertical load at the tyres. During cornering, a slight additional bias towards the front wheel(s) is beneficial. Despite the alteration in handling characteristics made available through ATD, the effects of weight distribution and tyre characteristics still dominate. At normal speeds, almost the same effect on automobile handling can be achieved through left–right torque vectoring in a front- or rear-wheel-drive vehicle, as in a four-wheel-drive vehicle. In these steady-state situations, the energy efficiency of the vehicles varies only by small amounts, with aerodynamic and lateral slip dissipations dominating. The models presented in this thesis, and the results and conclusions obtained from them, offer the designers of future vehicles useful information for the improvement of vehicle handling, efficiency and quality.

Thermal management is crucial in many engineering applications because it affects the electrical, material, and other properties of the system. A recent study focuses on the use of heat pipes for battery thermal management in electric vehicles, which explores a new area for heat pipe applications. The battery, as one and only energy source in an EV, establishes a vital barrier for automotive industry because it can make the car more expensive and less reliable. The modelling methodology developed in this thesis is a one-dimensional electrochemical model, decoupled and coupled with a three-dimensional flow and heat transfer model. A prototype for 2-cell prismatic battery cooling and preheating using heat pipes is developed, and a full experimental characterisation has been performed. The experimental results characterised system thermal performance as well as validating material properties/parameters for simulation inputs. Two surrogate cells filled with atonal 324 were used in this experiment. The eligibility of substituting atonal 324 for lithium-ion battery electrolytes has been assessed and confirmed. The consistency demonstrated between the finite element analysis and the experiment facilitates BTM simulation at pack level, which is a scale-up model containing 30 lithium-ion batteries. The study shows that heat pipes can be very beneficial to reduce thermal stress on batteries leading to thermally homogenous packs. Additionally, an attempt of integrating biomimetic wicks for ultra-thin flat plate heat pipes is made in response to space limitations in microelectronics cooling. To date, no one has devised an ultra-thin FPHP with enough vapour space by constructing different wicks for each heat pipe segment, especially under anti-gravity condition. It is thus interesting to see whether a new type of wick structure can be made to achieve an optimum heat transfer potential.

With the dramatic development of the automotive industry and global economy, the motor vehicle has become an indispensable part of daily life. Because of the intensive competition, vehicle manufacturers are investing a large amount of money and time on research in improving the vehicle performance, reducing fuel consumption and meeting the legislative requirement of environmental protection. Engine calibration is a fundamental process of determining the vehicle performance in diverse working conditions. Control maps are developed in the calibration process which must be conducted across the entire operating region before being implemented in the engine control unit to regulate engine parameters at the different operating points. The traditional calibration method is based on steady-state (pseudo-static) experiments on the engine. The primary challenge for the process is the testing and optimisation time that each increases exponentially with additional calibration parameters and control objectives. This thesis presents a basic dynamic black-box model-based calibration method for multivariable control and the method is applied experimentally on a gasoline turbocharged direct injection (GTDI) 2.0L virtual engine. Firstly the engine is characterized by dynamic models. A constrained numerical optimization of fuel consumption is conducted on the models and the optimal data is thus obtained and validated on the virtual system to ensure the accuracy of the models. A dynamic optimization is presented in which the entire data sequence is divided into segments then optimized separately in order to enhance the computational efficiency. A dynamic map is identified using the inverse optimal behaviour. The map is shown to be capable of providing a minimized fuel consumption and generally meeting the demands of engine torque and air-fuel-ratio. The control performance of this feedforward map is further improved by the addition of a closed loop controller. An open loop compensator for torque control and a Smith predictor for air-fuel-ratio control are designed and shown to solve the issues of practical implementation on production engines. A basic pseudo-static engine-based calibration is generated for comparative purposes and the resulting static map is implemented in order to compare the fuel consumption and torque and air-fuel-ratio control with that of the proposed dynamic calibration method. Methods of optimal test signal design and parameter estimation for polynomial models are particularly detailed and studied in this thesis since polynomial models are frequently used in the process of dynamic calibration and control. Because of their ease of implementation, the input designs with different objective functions and optimization algorithms are discussed. Novel design criteria which lead to an improved parameter estimation and output prediction method are presented and verified using identified models of a 1.6L Zetec engine developed from test data obtained on the Liverpool University Powertrain Laboratory. Practical amplitude and rate constraints in engine experiments are considered in the optimization and optimal inputs are further validated to be effective in the black box modelling of the virtual engine. An additional experiment of input design for a MIMO model is presented based on a weighted optimization method. Besides the prediction error based estimation method, a simulation error based estimation method is proposed. This novel method is based on an unconstrained numerical optimization and any output fitness criterion can be used as the objective function. The effectiveness is also evaluated in a black box engine modelling and parameter estimations with a better output fitness of a simulation model are provided.

This thesis presents closed loop control of active Gurney flaps on rotors. Firstly, it builds on the Helicopter Multi-Block 2 CFD solver of the University of Liverpool and demonstrates the implementation and use of Gurney flaps on wings, and rotors. The idea is to flag any cell face within the computational mesh with a solid, no slip boundary condition. Hence the infinitely thin Gurney can be approximated by “blocking cells” in the mesh. Comparison between thick Gurney flaps and infinitely thin Gurneys showed no difference on the integrated loads, the same flow structure was captured and the same vortices were identified ahead and behind the Gurney. The results presented for various test cases suggest that the method is simple and efficient and it can therefore be used for routine analysis of rotors with Gurney flaps. The potential effect of a Gurney flap all over the performance of the W3-Sokol rotor blade in hover was studied next. A rigid blade was first considered and the calculations were conducted at several thrust settings. The Gurney flap was extended from 46%R to 66%R and it was located at the trailing edge of the main rotor blade. Four different sizes of Gurney flaps were studied, 2%, 1%, 0.5% and 0.3% of the chord, and the biggest flap proved to be the most effective. A second study considered elastic blades with and without the Gurney flap. The results were trimmed at the same thrust values as the rigid blade and indicate an increase of aerodynamic performance when the Gurney flap is used, especially for high thrust cases. Moreover, the performance of the W3-Sokol rotor in forward flight with and without Gurney flap was tested. Rigid and elastic blade models were considered and calculations were guided using flight test data. The Gurney flap was extended from 40%R to 65%R, while the size of the Gurney was selected to be 2% of the chord based on the hover study. All results were trimmed to the same thrust as flight tests. The harmonic analysis of the flight test data proved to be a useful tool for identifying vibrations on the rotor caused by stall at the retreating side, and a carefully designed Gurney flap and actuation schedule were essential to alleviate the effects of flow separation. The last part of the thesis is dedicated to a closed loop actuation of the Gurney flap based on the leading edge pressure divergence criterion. The effect of the Gurney flap on the trimming of a full helicopter model, as well as the handling qualities of the rotorcraft were investigated. To the author’s knowledge this is the first attempt to study the effect of active Gurney flaps on elastic rotors with 3D CFD in a closed loop control for retreating blade stall alleviation and hover performance enhancement. The idea is that Gurney will stay deployed during the hover and it will be actuated based on the forward flight demands in order to enhance the rotorcraft capabilities.

The research reported here was driven by a desire to obtain a prediction method for helicopter rotor performance that would have sufficient resolution to evaluate changes to the design of the blade tip. This thesis examines the effectiveness of Computational Fluid Dynamics (CFD) methods to solve this problem. An accurate, high-fidelity prediction is essential to quantify the performance of a new rotor tip shape which hitherto could not be properly assessed by a traditional approach. The CFD method lends itself to the resolution of the compressible, viscous flow around the helicopter blade tip. Starting from the surface shape required to generate a grid, together with the flow conditions, the flowfield naturally evolves from the numerical solution of the Navier-Stokes equations, based on the principles of conservation of mass, momentum and energy. Thus both the flow physics and the geometry of the tip are fully modelled by this technique. In order to demonstrate the process, the Helicopter Multi-block solver (HMB) is used to predict the performance of a series of example tail rotor configurations. The various tip shapes are evaluated and compared, initially using an Euler approach to economically cover a wide range of designs, before going on to apply the Navier-Stokes method. The concepts behind each of the tail rotor blade (TRB) tip designs are explained in the thesis. As further computational resources became available, the datum blade, and the down-selected Kuchemann-like and anhedral-Kuchemann tip blades were the subject of Navier-Stokes predictions. Early in this work, the numerical method was validated against published data, and was also compared to existing model tail rotor test data for blades having different twist. In the central part of this thesis, the computational results are further analysed to reveal the influence of blade design changes on the time-averaged induced flow, and to extract more familiar aerodynamic parameters such as the angle of attack from the 3D rotor computations. Steady Navier-Stokes predictions were obtained over a range of pitch angles such that the induced power factor could be reliably determined and the trends on profile power could also be established for the selected tip shapes. The research reported in this thesis has established that this numerical approach provides a good prediction of rotor performance, adequately resolving the flow-field and tip aerodynamics. Since the assessment of helicopter rotors may involve additional interactional effects, or a degree of unsteady flow due to operating at high pitch angles near the onset of stall, an unsteady case was also demonstrated for a tail rotor blade adjacent to a fin. It is concluded that only by using a CFD approach can a sufficiently high-fidelity prediction be obtained for helicopter rotor aerodynamics to allow progressive enhancements of future helicopter blade designs.

In the presence of aerodynamic turbulence, very flexible aircraft exhibit large deformations and as a result their behaviour is characterised as intrinsically nonlinear. These nonlinear effects become significant when the coupling of rigid–body motion with nonlinear structural dynamics occurs and needs to be taken into account for flight control system design. However, control design of large–order nonlinear systems is challenging and normally, is limited by the size of the system. Herein, nonlinear model order reduction techniques are used to make feasible a variety of linear and nonlinear control designs for large–order nonlinear coupled systems. A series of two–dimensional and three–dimensional test cases coupled with strip aerodynamics and Computational– Fluid–Dynamics is presented. A systematic approach to the model order reduction of coupled fluid–structure–flight dynamics models of arbitrary fidelity is developed. It uses information on the eigenspectrum of the coupled-system Jacobian matrix and projects the system through a Taylor series expansion, retaining terms up to third order, onto a small basis of eigenvectors representative of the full–model dynamics. The nonlinear reduced–order model representative of the dynamics of the nonlinear full–order model is then exploited for parametric worst–case gust studies and a variety of control design for gust load alleviation and flutter suppression. The control approaches were based on the robust H∞ controller and a nonlinear adaptive controller based on the model reference adaptive control scheme via a Lyapunov stability approach. A two degree–of–freedom aerofoil model coupled with strip theory and with Computational–Fluid–Dynamics is used to evaluate the model order reduction technique. The nonlinear effects are efficiently captured by the nonlinear model order reduction method. The derived reduced models are then used for control synthesis by the H∞ and the model reference adaptive control. Furthermore, the numerical models developed in this thesis are used for the description of the physics of a wind–tunnel model at the University of Liverpool and become the benchmark to design linear and nonlinear controllers. The need for nonlinear control design was demonstrated for the wind–tunnel model in simulation. It was found that for a wind–tunnel model with a cubic structural nonlinearity in the plunge degree–of–freedom, conventional linear control designs were inadequate for flutter suppression. However, a nonlinear controller was found suitable to increase the flight envelope and suppress the flutter. A large body of work dealt with the development of a numerical framework for the simulation of the flight dynamics of very flexible aircraft. Geometrically–exact nonlinear beam structural models were coupled with the rigid–body, the flight dynamics degrees–of–freedom and the strip theory aerodynamics, for the description of the nonlinear physics of free–flying aircraft. The flexibility effects of these vehicles on the flight dynamic response is quantified. It is found that different angle of attack and control input rotation is needed to trim a flexible aircraft and that a rigid analysis is not appropriate. Furthermore, it is shown that the aircraft flexibility has an impact on the flight dynamic response and needs to be included. The fully coupled models are consequently reduced in size by the nonlinear model reduction technique for a cheaper and a simpler computation of a variety of linear and nonlinear automatic control designs that are applied on the full–order nonlinear models inside the developed framework for gust load alleviation. The approach is tested on a Global Hawk type unmanned aerial vehicle developed by DSTL, on a HALE full aircraft configuration, and on a very large flexible free–flying wing. A comparison of the developed control algorithms is carefully addressed with the adaptive controller achieving better gust loads alleviation in some cases. Finally, future possible implementations and ideas related to the nonlinear model order reduction and the control design of flexible aircraft are discussed.

The benefits of using flight simulators for rotorcraft design, certification and pilot training include reduced costs, increased safety, and control over external parameters such as environmental conditions and operational situations. The progression of technology and computing power over recent decades has led to the ability to manufacture highly sophisticated flight simulators that can be used to train complex flight operations and accurately predict the behaviour aircraft. However, such sophistication comes at a cost and there is a need to understand the trade-offs between cost and effectiveness to allow the benefits of flight simulation to be transferred to lower cost applications such as initial skills acquisition training. Assessment of simulator capabilities has traditionally been carried out with focus on the physical similarity of individual components of the simulator systems - motion system, visual system, flight model etc. However, this work is focused on the assessment of the fitness for purpose of the integrated system as a whole. This is referred throughout the thesis as perceptual fidelity, which has been defined as 'The simulator's ability to induce the behaviours known to be essential for operation of the actual aircraft in the performance of a specific task'. The novel contribution of the work in this thesis is the development of new quantitative metrics and a subjective evaluation technique that could be utilised across the simulation industry for quantification of perceptual fidelity of the overall simulation. It is intended that the methods detailed in this work could be used to support simulator development and augment current assessment techniques where appropriate. The quantitative measures of perceptual fidelity are based on comparison of ADS-33E PRF style performance metrics and the Attack metric, a control activity measure developed by Padfield et al. In this work, the utility of these metrics was assessed through correlation analyses with pilot subjective opinion. A lack of correlation in multi-axis tasks was seen and, as a result, novel metrics of pilot control strategy and adaptation have been developed in this work that show significant improvement in correlation with pilot subjective opinion. The subjective assessment methodology developed in this work is based around a new subjective rating scale – the Simulation Fidelity Rating (SFR) scale. The author contributed to the development of the SFR scale along with others at the University of Liverpool and the National Research Council (NRC) of Canada. This scale has been designed specifically to be industry applicable a d to determine the overall perceptual fidelity of the integrated simulation in a specific role. A campaign of piloted simulation and flight test trials has been conducted as the core experimental phase of this work. All the pilots completed a series of controlled experiments where a number of flying tasks were completed with a number of varied simulation models. The pilots rated each simulation against a baseline simulation using the SFR scale and their performance and control activity were recorded. This test campaign generated the pilot feedback for the development of the SFR scale and data for development of the quantitative metrics. The tests were also utilised to demonstrate how this assessment methodology can be used in controlled simulation experiments to provide previously lacking supporting evidence to simulator qualification criteria of individual components. From the analysis of the results, it was found that a more aggressive pilot excites the dynamics of the aircraft to a greater extent, thereby exposing more fidelity issues – leading to poorer SFRs. For similar reasons, an aircraft with degraded HQs was found to cause increased pilot sensitivity to transport delay. Perceptual fidelity was also found to be task dependent, In particular, pilots were found to be more susceptible to changes in off-axis response in the Acceleration-Deceleration manoeuvre than in the Precision Hover manoeuvre. These findings prove that here is a true need for simulation qualification criteria that are based on the intended use of the equipment. Significant spread was seen in the pilot ratings of perceptual fidelity in a number of cases. This was attributed partly to differing interpretation of the terminology within the Simulation Fidelity Rating (SFR) scale and also to pilot selection of task strategy. Therefore guidance material has been developed by the author from lessons learnt throughout the test campaign. This guidance material is intended to ensure best utility of the SFR scale in the future, to mitigate against the effects of differing interpretation of SFR terminology and variation in pilot task strategy through pilot briefing and correct experimental design. The SFR scale has been developed in the context of assessing a simulator for the purpose of rotary wing skills acquisition training. However, the methodologies described throughout the thesis are intended to be transferable to more sophisticated training devices for rotary-wing and fixed-wing pilot and crew training as well as for the quantification of the fidelity of certification and design simulators.

The aim of this Engineering Doctorate was to identify and develop strategies and technologies to overcome the barriers to sustainable motorsport. A top-down approach was taken beginning with an industry-wide strategy and ending with the development of individual sustainable technologies. After identifying a set of target guidelines for the industry to follow, the economic, social and environmental barriers to the future sustainability of motorsport were identified. These barriers were addressed through the creation of an industry-wide regulatory strategy followed by an innovative company-focussed technology development process; High Performance Sustainability (HPS). The HPS process was used to develop Eco One, a revolutionary racing car featuring environmentally sustainable technology which generated significant public engagement and facilitated evaluation of the HPS process. This technology demonstrator was used to make iterative improvements to the HPS process, resulting in HPS2, a second generation process with greater focus on performance and the development of sustainable technology. This novel process was used to research and develop individual environmentally-sustainable technologies; natural fibre reinforced composites and the use of high performance biodiesel. Firstly lignin, a natural, renewable, waste material was added to hemp/epoxy composites as an innovative compatibiliser with a resulting improvement in mechanical properties. Secondly, engine parameters were modified for the use of biodiesel made from soybean oil, resulting in torque equal to diesel fuel but with a lower in-cylinder pressure. The impact of these technologies is the opportunity to use renewable materials for high performance applications, potentially competing with existing motorsport technology. The innovations presented in this Engineering Doctorate led to recognised expertise in sustainable motorsport within WMG, and in turn resulted in sustainable motorsport projects including WorldFirst, in which a Formula 3 car was developed featuring natural fibre composites, high performance biodiesel and recycled carbon fibre components. The impacts of this work are the establishment of industrial projects with race teams and constructors, conference attendances and peer-reviewed publications, and dissemination of research through the development of academic courses and extensive media coverage.

The development and experimental testing of the DUKW-Ling amphibious vehicle was performed during the first phase of an autonomous amphibious vehicle system development project. The DUKW-Ling is a 1/7th scale model of a cargo transport concept vehicle. The vehicle was tested in the three regions it is required to operate: land, sea and the surf zone region. Vehicle characteristics such as turning radii, yaw rate and velocities were found for different motor inputs on land and water. Also, because a vehicle navigating the surf zone is a new area of research that lacks experimental data the vehicle was tested in the breaking waves of the surf zone and its motion characteristics were found, as well as the drivetrain forces required to perform this transition. Maneuvering tests provided data that was used to estimate a model for future autonomous control efforts for both land and water navigation. / by Joseph G. Marquardt. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography.

The hazard perception skill of a driver refers to their ability to identify potentially dangerous events on the road, and is one of the only driving-specific skills that has been consistently linked to accident rates. Hazard perception tests are used in several developed countries as part of the driver licensing curriculum, however little research has been done in developing countries where road safety is a primary concern. The extent to which hazard perception skill transfers to different driving environments is also unclear. This thesis therefore has two major aims: to examine hazard perception in a cross-cultural context, and to validate a hazard perception test for potential use in driver licensing in lower-income, developing countries. Most of the experiments in this thesis compare hazard perception skill in drivers from the UK – where hazard perception testing is well established – and drivers from Malaysia – a developing country with a high accident rate where hazards frequently occur. Typically, hazard perception skill is assessed by showing participants clips filmed on the road and asking them to respond as soon as they detect a developing hazard, with shorter response times reflecting greater levels of skill. Chapter 2 presents evidence that Malaysian drivers may be desensitized to hazardous road situations and thus have increased response times to hazards, creating validity issues with the typical paradigm. Subsequent chapters therefore use a predictive paradigm called the “What Happens Next?” test that requires drivers to predict hazards, leaving performance unaffected by hazard desensitization. Malaysian drivers predicted hazards less accurately than UK drivers in all cross-cultural experiments, indicating that exposure to a greater number of hazards on Malaysian roads did not have a positive effect on participants’ predictive hazard perception skill. Further experiments indicated that explicit knowledge plays a minor role in the “What Happens Next?” test, and that experienced drivers appear to compensate for reduced visual information more effectively than novices. Experienced drivers from both Malaysia and the UK also outscored novices in all experiments using the predictive paradigm, suggesting the “What Happens Next?” test provides a valid measure of hazard perception skill and may offer a practical alternative for hazard perception testing in developing and even developed countries.