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Nuisance vibrations are a concern throughout the engineering realm, and many researchers are dedicated to finding a solution to attenuate them. This research primarily focusses upon the suppression of vibrations in a robot system, with the control system being designed so that it is both affordable and lightweight. Such constraints aim to provide a solution that may be utilised in a variety of applications. The utilisation of piezoelectric elements as both actuators and sensors provides several advantages in that they are lightweight, easily integrated into an existing system and have a good force to weight ratio when used as actuators. To read and control these elements a single board computer was employed, in acknowledgement of the constraining parameters of the design. The amalgamation of vibration control and robotics has lent to the research being conducted with separate objectives set, isolating certain elements of the overall system design for validation. Ultimately, these separate investigations progress to the integration of the robot and control systems prior to further research concerning nonlinear vibrations, dynamic control and the discrete-time domain modelling of the system. This research first investigates the viability of the chosen components as a vibration attenuation solution. In addition, analytical models of the system have been created, for two types of sensors to determine the most effective; an inertial measurement unit and a collocated pair of piezoelectric sensors. These models are based on Euler-Bernoulli beam theory and aim to validate the control theory through a comparison of the experimental data. These experiments isolate the vibration problem from a robot system through the investigation of the control of a long slender beam envisioned as a robot manipulator link, but excited using a shaker platform in a sinusoidal manner. An observation of the theory related to the voltage produced by the piezoelectric elements, suggests that even with the application of only proportional control by the system, the controlled output would have components indicative of both proportional and derivative control. This observation and the underlying theory are further analysed within this research. The next objectives are to compare the performance of the control system developed in this research which utilises a Raspberry Pi 3B+ [1] with one that employs a dSPACE MicroLabBox [2], and to determine the suitability of the former for use with robot systems. With the former ensuring that the constraints placed on the design, those which influenced the selection of the components, does not conclude to the dSPACE Micro-LabBox system being overtly preferable. The latter investigates both the impact of the system's inclusion on the functionality of the system and the system's performance with respect to the intended application. The KUKA LBR iiwa 7 R800 [3] robot manipulator is utilised to satisfy this objective, wherein the link is mounted on the end effector of the manipulator acting as an eighth link. The final investigation in this research pertains to the attenuation of nonlinear vibrations experienced by a robot manipulator link. Additional components were added to the link to induce a geometric nonlinearity in the system. An analytical model of the amended system was created to validate the theory through comparison with experimental results. The control system was employed for multiple cases to ascertain the level of its performance with regards to the suppression of nonlinear vibrations.

Linear Friction Welding (LFW) is a relatively new process adopted by aircraft engine manufacturers utilising new technologies to produce better value components. With increasing fuel prices and economical drives for reducing CO2 emissions, LFW has been a key technology in recent years for aircraft engine manufacture in both commercial and military market sectors. For joining Blades to Discs (‘Blisks’), LFW is the ideal process as it is a solid state process which gives reproducibility and high quality bonds therefore improving performance. The welding process is also more cost effective than machining Blisks from solid billets, and a reduction in weight can also be achieved with the use of hollow blades. The LFW process also allows dissimilar materials to be joined and a reduction in assembly time. The main aim of the research is to create a simulation model of a Linear Friction Welding machine and also apply systems thinking to fully understand the LFW process with a view to reduce total production costs. As this EngD focuses on systems thinking, a holistic approach will be used. The hard systems parts of this project will involve the mechanics of the system and understanding relationships between the key system interactions during the welding process in order to create an analytical model of the machine to use for fault diagnosis and prediction. The soft systems parts will focus on the machine users to gain an understanding of how to effectively implement the model with the process and its users. The benefits of the new model include the ability to execute it in a real- time environment with machine operation, allowing weld anomalies to be detected as (and in some cases before) they occur, as well as the monitoring of the machine’s condition. Therefore the business benefits would be realised through a reduction in machine downtime enabling the timely supply of goods providing customer value. Further benefits will be the greater understanding of the complex operation of the whole system and the welding process. Developing a robust research investigation framework, a research hypothesis is introduced and subsequent research questions are developed. Through a combination of hard system investigation using mathematical modelling and soft systems understanding through an action case study intervention, a holistic model is developed.

The application of transgenic technology to teleost fish has two primary goals; the manipulation of specific traits in commercially important species for economic gain, and the use of small teleost fish, such as the zebrafish (Danio rerio), as a model system to study vertebrate development and gene regulation. To realise each of these goals efficient gene transfer and a reliable means of assaying the functionality of cis-acting regulatory elements are required. The efficiency of gene transfer by egg electroporation was compared with microinjection. Removal of the egg envelope, the chorion, was absolutely necessary to achieve gene transfer by electroporation. The process of dechorionation and the low survival of denuded embryos suggests it is unlikely that the electroporation of dechorionated fish eggs will be adopted as an alternative method of gene transfer until more successful methods of culturing denuded embryos are developed. Using quantitative transient transgene expression assays it was possible to resolve functional differences between cis-acting regulatory elements of different origin, in this case the β-cytoplasmic actin genes of two evolutionarily distant classes of vertebrates. Hybrid 'intron exchange' constructs, demonstrated that cis-regulatory elements residing within carp intron I were necessary for high level expression in fish. Mis-splicing was observed with the equivalent mammalian sequence. High variability in expression levels was found with transient transgene assays, which may seriously influence quantitative comparative analyses. An attempt was made to elucidate the source of this observed variability. High levels of transgene expression were found to occur in the yolk syncytial layer (YSL).