Modeling, Control and Optimisation of Hybrid Systems in a Manufacturing Setting

This study comprises a body of work that investigates the performance of hybrid manufacturing systems. And we have provided a valuable insight into the development of the optimisation techniques for hybrid manufacturing system. With the primary objective of developing prac-tical mathematical algorithms that balance trade-o? cost between product quality and completion time. For sta-bility criterion, a sliding mode control was deployed

Type-2 Fuzzy Hybrid Controller Network for Robotic Systems

Dynamic control, including robotic control, faces both the theoretical challenge of obtaining accurate system models and the practical difficulty of defining uncertain system bounds. To facilitate such challenges, this paper proposes a control system consisting of a novel type of fuzzy neural network and a robust compensator controller. The new fuzzy neural network is implemented by integrating a number of key components embedded in a Type-2 fuzzy cerebellar model articulation controller (CMAC) and a brain emotional learning controller (BELC) network, thereby mimicking an ideal sliding mode controller. The system inputs are fed into the neural network through a Type-2 fuzzy inference system (T2FIS), with the results subsequently piped into sensory and emotional channels which jointly produce the final outputs of the network. That is, the proposed network estimates the nonlinear equations representing the ideal sliding mode controllers using a powerful compensator controller with the support of T2FIS and BELC, guaranteeing robust tracking of the dynamics of the controlled systems. The adaptive dynamic tuning laws of the network are developed by exploiting the popular brain emotional learning rule and the Lyapunov function. The proposed system was applied to a robot manipulator and a mobile robot, demonstrating its efficacy and potential; and a comparative study with alternatives indicates a significant improvement by the proposed system in performing the intelligent dynamic control

Novel ultra-violet/blue optoelectronic materials and devices based on copper halides (CuHa)

Considerable research is being carried out in the area of wide band gap semiconductor materials for light emission applications in the UV/Blue (300-400 nm) spectral range. This project explores the novel use of the Copper Halides (CuHa), specifically γ-CuCl and γ-CuBr, I–VII wide band gap mixed ionic–electronic semiconducting materials with light emitting properties suitable for novel UV/blue light applications. This project details novel research carried out towards achieving single crystal growth of γ-CuCl from solution via Liquid Phase Epitaxy (LPE) based techniques. LPE growth runs are undertaken using an alkali halide flux compound (KCl) to depress the liquidus temperature of CuCl below its solid phase wurtzite-zincblende (β → γ) transition temperature for solution based epitaxy on lattice matched Si substrates (lattice constant of γ-CuCl (0.541 nm) is closely matched to that of Si (0.543 nm). Results show that the resulting KCl flux-driven deposition of CuCl onto the Si substrate has yielded superior photoluminescence (PL) and X-ray excited optical luminescence (XEOL) behaviour relative to comparatively observed spectra for GaN or polycrystalline CuCl. The resulting deposited material is a textured CuCl/K2CuCl3 polycrystalline intermix, with strong broad luminescence and novel luminescent characteristics not previously observed in CuCl. Difficulties inherent to LPE with CuCl/KCl melts, particularly with the CuCl/KCl eutectic system and the CuCl/Si surface reaction, are detailed. The use of γ-CuBr for thin film based blue light emitting devices is investigated. Its structural and physical properties allow for vacuum deposition on a variety of substrates and herein we report on the deposition of γ-CuBr on Si, glass and indium tin oxide coated glass substrates via vacuum evaporation with controllable film thickness from 100 to 500 nm. Temperature dependent photoluminescence characteristics of these γ-CuBr films on Si substrates reveal familiar Zf and I1 excitonic features. Work towards the development of a thin filmelectroluminescent device using a γ-CuBr active layer is outlined. Recently, dramatic improvements in the luminescent intensity of CuBr generated by the chemical interaction between CuCl films and KBr substrates have been demonstrated. The potential improvements in excitonic PL that can be gained from novel approaches to film preparation involving KBr and existing CuBr deposition techniques is promising. We report on the one such novel approach, the vacuum deposition of KBr spots (~30 µm radius) onto similarly deposited γ-CuBr epitaxial layer on a Si substrate. Post-deposition annealing of the samples at 220 °C in conjunction with a small CuBr flux from a target source leads to the formation of intermixed CuBr/ KBr microdots. PL characterisation reveals enhanced UV-Blue excitonic emission centered on the Zf free exciton peak at ~418 nm, far superior to Zf emission from γ-CuBr films deposited previously. An overview of the deposition process involving shadow masks to lay down an ordered array of KBr spots onto a γ-CuBr vacuum evaporated layer is presented, and the samples are characterised using XRD, EDX and spatially resolved room temperature PL