Pneumatic motion control systems for modular robots

This thesis describes a research study in the design, implementation, evaluation and commercialisation of pneumatic motion control systems for modular robots. The research programme was conducted as part of a collaborative study, sponsored by the Science and Engineering Research Council, between Loughborough University and Martonair (UK) Limited. Microprocessor based motion control strategies have been used to produce low cost pneumatic servo-drives which can be used for 'point-to-point' positioning of payloads. Software based realtime control strategies have evolved which accomplish servo-controlled positioning while compensating for drive system non-linearities and time delays. The application of novel compensation techniques has resulted in a significant improvement in both the static and dynamic performance of the drive. A theoretical foundation is presented based on a linearised model of a pneumatic actuator, servo-valve, and load system. The thesis describes the design and evolution of microprocessor based hardware and software for motion control of pneumatic drives. A British Standards based test-facility has allowed control strategies to be evaluated with reference to standard performance criteria. It is demonstrated in this research study that the dynamic and static performance characteristics of a pneumatic motion control system can be dramatically improved by applying appropriate software based realtime control strategies. This makes the application of computer controlled pneumatic servos in manufacturing very attractive with cost performance ratios which match or better alternative drive technologies. The research study has led to commercial products (marketed by Martonair Ltd), in which realtime control algorithms implementing these control strategy designs are executed within a microprocessor based motion controller

Modelling and analysis of traction control systems in automobiles

This thesis begins with a brief overview of vehicle control. The thesis places powertrain control, which is discussed in more detail, within the wider context of vehicle control. Traction control is one aspect of powertrain control. The available methods of traction control are reviewed together with a discussion on the systems in current production. The traditional method adopted by the automotive industry for traction control is analysed. The powertrain system is analysed from a control stand-point and a control oriented approach to traction control design identified. The emphasis in this thesis is on the analysis of traction control systems. The analysis is performed on simulation models and is supported by implementations on the real vehicle. The level of modelling appropriate for the analysis is justified and models developed in a modular manner. The individual modules are developed on the basis of published material and previous work within Ford Motor Company. Based on the analysis, two traction control strategies are developed which are subsequently developed and implemented on real vehicles. The results of this vehicle work is discussed

Control for transient response of turbocharged engines

The concepts of engine downsizing and down-speeding offer reductions in CO2 emissions from passenger cars. These reductions are achieved by reducing pumping and friction losses at part-load operation. Conventionally, rated torque and power for downsized units are recovered by means of turbocharging. The transient response of such engines is, however, affected by the static and dynamic characteristics of the turbo-machinery. Recent advances in engine simulation and control tools have been employed for the purpose of the research reported in this thesis to identify and verify possible air-path enhancements. A systematic method for evaluating various turbocharger assistance concepts is proposed and discussed in this thesis. To ensure a fair comparison of selected candidate systems, an easily reconfigurable controller providing a close-to-optimal operation, while satisfying physical limits, is formulated. This controller is based on the Model Predictive Control framework and uses a linearised mean value model to optimise the predicted behaviour of the engine. Initially, the controller was applied to a 1D simulation model of a conventional light-duty Diesel engine, for which the desired closed-loop features were verified. This procedure was subsequently applied to various air-path enhancement systems. In this thesis, a turbocharger electric assistance and various concepts based on compressed gas injection were considered. The capability of these systems to improve engine response during third gear tip-in manoeuvre was quantified. This investigation was also complemented with a parametric study of how effectively each of the considered methods used its available resources. As a result, injecting compressed gas into the exhaust manifold was identified as an effective method, which to date has attracted limited attention from engine research community. The effectiveness of the exhaust manifold assistance was experimentally verified on a light-duty Diesel engine. The sensitivity of the improvements to compressed gas supply parameters was also investigated. This led to the development of the BREES system: a low component count, compressed gas based system for reducing turbo-lag. It was shown that during braking manoeuvres a tank can be charged to the level sufficient for a subsequent boost assistance event. Such a functionality was implemented with a very limited set of additional components and only minor changes to the standard engine control.This work was supported by the Engineering and Physical Sciences Research Council [grant number EP/G066477/1

The assessment of a rotorcraft simulation model in autorotation by means of flight testing a light gyroplane

The simulation and flight testing of a light gyroplane aircraft is performed obtaining results regarding the flight dynamics attributes of the vehicle. The main aim of the work was to assess the ability of a mathematical model to simulate rotorcraft in the autorotative flight state. Additionally, the results acquired were to enhance the understanding of an aircraft class for which the existing database of knowledge is limited, particularly with regards to its flight mechanics characteristics. An appropriate aircraft configuration file was obtained enabling a platform of simulation results to be generated. Parametric studies were performed primarily focusing on the influence of the vertical centre of gravity position and rotor speed degree of freedom on gyroplane longitudinal stability. A data acquisition system unique in its sophistication for this class of aircraft was developed and installed on board. The software required to drive the system was designed, and rigorous tests verifying the instrumentation functionality were conducted both on ground and in real flight. A flight test programme capable of fulfilling the experimental aims was devised and realised, yielding results both on the steady state flight characteristics of the aircraft and its dynamic response to pilot inputs. Certain trends were established on the properties of gyroplanes by interpreting the results in terms of basic aerodynamic theory, and by comparing them to previous research findings. A comparison of the experimental data to that obtained from the simulation runs, served to fulfil the model validation aim of the work presented. The effect of model and flight discrepancies on the ability of the mathematical model to realistically emulate flight dynamics in autorotation was discussed, and possible suggestions for the reasons of mismatch were presented

Performance and Safety Enhancement Strategies in Vehicle Dynamics and Ground Contact

Recent trends in vehicle engineering are testament to the great efforts that scientists and industries have made to seek solutions to enhance both the performance and safety of vehicular systems. This Special Issue aims to contribute to the study of modern vehicle dynamics, attracting recent experimental and in-simulation advances that are the basis for current technological growth and future mobility. The area involves research, studies, and projects derived from vehicle dynamics that aim to enhance vehicle performance in terms of handling, comfort, and adherence, and to examine safety optimization in the emerging contexts of smart, connected, and autonomous driving.This Special Issue focuses on new findings in the following topics:(1) Experimental and modelling activities that aim to investigate interaction phenomena from the macroscale, analyzing vehicle data, to the microscale, accounting for local contact mechanics; (2) Control strategies focused on vehicle performance enhancement, in terms of handling/grip, comfort and safety for passengers, motorsports, and future mobility scenarios; (3) Innovative technologies to improve the safety and performance of the vehicle and its subsystems; (4) Identification of vehicle and tire/wheel model parameters and status with innovative methodologies and algorithms; (5) Implementation of real-time software, logics, and models in onboard architectures and driving simulators; (6) Studies and analyses oriented toward the correlation among the factors affecting vehicle performance and safety; (7) Application use cases in road and off-road vehicles, e-bikes, motorcycles, buses, trucks, etc

An optimisation study on the control of clutch engagement in an automotive vehicle

This thesis contains a formal mathematical investigation of clutch engagement in automotive vehicles. This investigation is conducted by developing a model of an automotive powertrain, and investigating undesirable effects that can occur in clutch engagement. This naturally leads to the development of a multi-objective optimal control problem describing how to best to engage a clutch. An algorithm for solving this optimal control problem is then presented. Arguments for the development of a feedback control strategy are then discussed, with the construction of such a feedback strategy, along with the computations required to evaluate the feedback controls detailed. A further extension, of adapting the feedback controls, to cope with powertrain model perturbations then follows, along with a method of estimating such perturbations. Finally, the use of this research in implementing clutch engagement control is outlined. Throughout the thesis, the various control strategies designed are evaluated by carry out simulations of models representing the powertrains of two different family cars