Mechatronics Systems Engineering - Theses, Dissertations, and other Required Graduate Degree Essays

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Roll-to-Roll Transfer Printing of Reduced Graphene Oxide Thin Film

Author: 
Date created: 
2015-08-11
Abstract: 

A novel thin film transfer mechanism has been studied and developed to transfer chemically reduced graphene oxide (r-GO) thin film using a roll-to-roll printing system. We discover that shear stress generated on the silicon rubber stamp surface facilitates delamination of the deposited r-GO thin film efficiently.A roll-to-roll apparatus is assembled to demonstrate the shear-induced transfer printing in a large scale printing system. Shear stress is applied on the stamp surface by rotating the stamp side roller faster than the substrate side roller.The hydrophobic surface is changed to hydrophilic by polydopamine modification for 15 minutes at 60˚C in order for r-GO thin film to be directly deposited on the rubber stamp.Roll-to-roll printing parameters such as evaporation time during deposition of r-GO, vertical deformation of stamp, RPM, and RPM ratio between two rollers are investigated and adjusted for successful transfer of r-GO.With the adjusted roll-to-roll printing parameters, r-GO thin film has been transferred successfully to glass and PET substrates at a printing rate of 5mm/min. The shear stress required to transfer r-GO thin film in our experiment condition with glass substrate is estimated to be 325.43 kPa by experimental data and computation with ANSYS.A flexible transparent capacitive touch sensor is fabricated with printed r-GO thin film after the sheet resistance is significantly improved by thermal annealing process.Both the shear-induced roll-to-roll printing method and the stamp modification process are expected to contribute to large scale manufacturing systems for flexible printed electronics.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Woo Soo Kim
Edward Jung Wook Park
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Optimal Nonlinear Adaptive Observers for State, Parameter and Fault Estimation

Author: 
Date created: 
2015-07-30
Abstract: 

The demand for reliable, fast and robust techniques for detection and estimation of faults in real-world systems is constantly increasing. A nonlinear adaptive observer for state, parameter and fault estimation is developed in this work using an optimal approach. This observer is capable of estimating unknown parameters as well as sensor faults in the system. The proposed observer also accounts for existing noise and disturbance in the system. By defining appropriate cost functions for each problem, the observer is made to satisfy a performance bound. A systematic method of checking existence conditions and calculating observer gains in terms of Linear Matrix Inequalities (LMIs) is presented. Types of nonlinearities considered are fairly general and encompass sector bounded, Lipschitz and dissipative nonlinearities. The observer can identify time-varying unknown parameters, bias and gain sensor faults. Compared with the method of extended Kalman filter, the proposed observer is not computationally intensive and in its relaxed form, does not require online solution to the Ricatti equation. The observer is applied to representative state space models including a wind turbine mechanical power transmission mechanism. The considered system model is highly nonlinear and contains input disturbances as well. The results are compared with the results obtained from extended Kalman filtering and show satisfactory performance in the presence of noise and disturbances.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Krishna Vijayaraghavan
Department: 
Applied Sciences:
Thesis type: 
(Thesis) M.A.Sc.

Estimation of Chemical Oxygen Demand in WasteWater using UV-VIS Spectroscopy

Author: 
Date created: 
2015-05-08
Abstract: 

The aim of this research is to build a portable system to perform real-time analysis ofwaste water samples. Thus, that can significantly improve existing waste water treatmenttechnology. In waste water treatment plant, an important parameter, chemical oxygen demandis needed to be measured. The amount of chemical oxygen demand determinesthe degree of water pollution by organic material. The conventional method for measuringchemical oxygen demand requires sample preparation and pre-treatment using chemicals.These conventional techniques are time consuming and labour intensive. To overcomethese problems, a system is developed in this work that offers significant advantages overconventional methods. The system employs ultraviolet and visible spectrometer in orderto correlate the absorbance of light after it passes through a waste water sample with theconception of the target chemicals. The spectrometer limits the use and disposal of chemicalsfor the measurement of chemical oxygen demand. In addition, a software system isdeveloped to control the spectrometer and to detect the most sensitive spectral region andwavelength for chemical oxygen demand content. Moreover, an algorithm is introducedby performing linear regression analysis on acquired concentration and light absorbancefrom the acquired spectra. The development and validation of this spectroscopic tool andsoftware system are described in this thesis.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Behraad Bahreyni
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Bulk and interfacial thermal transport in microstructural porous materials with application to fuel cells

Date created: 
2015-04-13
Abstract: 

The performance, reliability and durability of fuel cells are strongly influenced by the operating conditions, especially temperature and compression. Adequate thermal and water management of fuel cells requires knowledge of the thermal bulk and interfacial resistances of all involved components. The porous, brittle and anisotropic nature of most fuel cell components, together with the micro/nano-sized structures, has made it challenging to study their transport properties and thermal behavior. The main purpose of this research was to explore, and guide the improvement of, the thermal behavior of fuel cell materials under compression. Thickness-based methods, having the capability of deconvoluting bulk from the contact resistance, were employed to accurately measure the thermal conductivity of several gas diffusion layers (GDLs) with different PTFE loading. The interfacial thermal resistances of these GDLs with adjacent micro porous layer (MPL) and graphite bipolar plate (BPP) were also determined, through both systematic experiments and comprehensive models developed in this work. The thermal conductivity of a coated MPL as a function of compression and that of a Ballard graphite BPP with respect to temperature were also measured and reported in this thesis. Higher values of contact resistance compared to the bulk resistance at low compression and the reduction of GDL thermal conductivity with PTFE loading are among the main findings of this study. The present work also revealed the following novel counter-intuitive facts: (i) contact resistance may decrease with increasing the porosity of the mating porous materials; (ii) the conventional notion that the thermal conductivity of fibrous materials decreases with increasing porosity does not necessarily hold; and (iii) fiber spacing can be as crucial as porosity to the transport properties of fibrous media. The main conclusion is that the equations that are based solely on porosity should be either discarded or used, with caution, over the limited range of conditions under which they have been formulated. Through a series of experiments combined with theoretical analyses, this thesis presents some key data that helps unravel some unexplained trends reported in the literature. It also provides novel insights into the unexplored thermal behavior of fuel cell components and guides the modification of their micro-structures for better heat management of fuel cells.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Majid Bahrami
Ned Djilali
Department: 
Applied Sciences:
Thesis type: 
(Thesis) Ph.D.

Design and Implementation of a Regenerative Shock Absorber

Author: 
Date created: 
2015-04-14
Abstract: 

In this thesis, the development of a novel regenerative shock absorber sized for a passengercar suspension system is studied. In the first phase, DC and AC rotary machines along with charging circuits, to be used in the energy conversion stage of the proposed shock absorber are analyzed. In this analysis, the rotary damping coefficients provided by these systems are obtained following by experimental results.In the second phase, the development of a novel regenerative shock absorber in a proof of concept setting is presented. This system consists of a new linear-to-rotary conversion mechanism called algebraic screw, a gearhead, and a rotary machine. The design and analysis of this system is presented. The linear damping coefficient provided by this shock absorber is obtained. Experimental results are presented that evaluate performance of the proposed system on a small-scale suspension system.In the third phase, the development of a novel regenerative shock absorber sized for a passenger car is presented. The shock absorber includes a simple and highly efficient motion converter stage called ”two-leg mechanism”, a planetary gearhead, and a brushless three-phase rotary machine. The design and analysis of the regenerative shock absorber is presented by considering the linear damping coefficient and efficiency of the electromechanical device. The performance of the regenerative shock absorber is evaluated under sinusoidal excitation inputs for typical amplitudes and frequencies in a vehicular suspensionsystem.In the fourth phase, the effect of nonlinear terms of the shock absorber on linear dampingcoefficient provided by this system is studied. Next, the idea of using a variable externalresistance, provided by the charging circuit, to compensate the nonlinear terms is presented.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences:
Thesis type: 
(Thesis) Ph.D.

Tissue Characterization and Cancer Detection Based on Bioimpedance Spectroscopy

Date created: 
2015-04-21
Abstract: 

Current research envisions improvement of breast cancer detection at early stages by adding a non-invasive modality, electrical impedance spectroscopy (EIS) to the detection procedure. The accuracy of clinical breast examination (CBE) is highly dependent on the clinician’s experience. EIS enhances the physician’s diagnostics capabilities by providing supplementary diagnostic information. Performing CBE besides EIS effects the electrical measurements of soft tissue. In this research the effect of the applied compression during CBE on the electrical properties is studied in-vitro and in-vivo. EIS is also tested over healthy and tumorous subjects. The correlation between tissue electrical properties and tissue pathologies is identified by offering an analysis technique based on the Cole-Cole model. Additional classification and decision making algorithms is further developed for cancer detection. This research suggests that the sensitivity of tumor detection will increase when supplementary information from EIS as well as the built-in intelligence is provided to the physician.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Farid Golnaraghi
Carolyn Sparrey
Department: 
Applied Sciences:
Thesis type: 
(Thesis) M.A.Sc.

An Environment for Advanced Simulation and Control of Lighting Systems

Author: 
Date created: 
2014-04-24
Abstract: 

Development of smart lighting systems can be considered under different perspectives. While a main business case for smart lighting is energy savings, another important consideration is the level of visual comfort experienced by the occupants. The latter aspect has been documented mainly in the context of the circadian system. A growing body of knowledge is related to the environmental impact of energy consumption related to lighting. The so-called layered lighting design, which aims at an effective combination of artificial and natural light, plays a key role in formal certification procedures for building design. This thesis presents two main contributions to the challenging area of the lighting industry: First, a lighting control scheme is proposed which integrates artificial lighting and daylight harvesting. Secondly, the development of an application programming interface is presented which allows one to integrate a control scheme with a simulated scene. The latter part of the contribution could be particularly beneficial for quasi-real-time validation of a lighting control algorithm against a virtual environment. The simulation environment can be deployed on a cloud environment. The case study discussed in this thesis is a scaled down version of an open-plan office lit through a set of individually addressable LED luminaries. It is further assumed that a second source of luminous flux is available in the form of natural light. The control problem consists of maintaining a level of illuminance which meets the users' requirements while minimizing the energy consumption. The proposed intelligent lighting system is based on an adaptive multivariable control scheme where the parameters of the model are determined through a simple identification procedure. The behaviour of the control system was validated through simulation studies and tested on a small scale room. Test results clearly show that a smart lighting system designed around the layered lighting design paradigm is indeed a compelling business case.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Laser-Scribed Photo-thermal Reduction of Graphene-Oxide for Thin Film Sensor Applications

Date created: 
2015-04-24
Abstract: 

In this thesis, a cost effective, simple and fast method of reduction of Graphene Oxide thin film is proposed. Graphene oxide is a non-conductive material intrinsically and one of the techniques to convert it to conductive material is using laser beam to remove oxygen groups from its surface, in other words, to reduce it. Laser parameters must be optimized for an effective and successful reduction. Thin film of non-conductive Graphene oxide is converted into conductive thin layer by fast laser scribing. Laser variables such as, power, speed, laser head distance to surface need to be selected precisely. Optical and atomic microscopies are used to study the changes of thin film surface. Chemical analysis shows that the reduction is successful and the structure is Graphene and removing of oxygen groups from surface is successful. Electrical properties also confirm the conductivity of scribed Graphene oxide. To show the application of reduced Graphene oxide, laser scribing method is used to fabricate pressure sensors arrays and the final product shows acceptable sensitivity to light touches similar to scrolling with finger on a touch screens. The fabricated sensor array is attachable on any surface for monitoring applied forces or pressure and maintains good electrical conductivity under mechanical stress and thus holds promise for durable sensors. Beside the pressure sensor, reduced Graphene oxide thin film has been used to fabricate temperature sensor. Also thin layer of hybrid (Graphene oxide mixed with silver nano wire) is deposited and patterned in the form of interdigitated capacitor to test the capacitance change of touch sensor.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Woo Soo Kim
Department: 
Applied Sciences:
Thesis type: 
(Thesis) M.A.Sc.

Design, Simulation, and Fabrication of a Lightweight Magneto Rheological Damper

Date created: 
2014-03-05
Abstract: 

Mountain biking has significantly evolved recently, thanks to utilizing cutting-edge technologies in mountain bicycle design and fabrication. In this research we study development of a semi-active suspension system using magneto-rheological (MR) fluid dampers instead of conventional oil based shocks. MR dampers are devices with magnetic field dependent damping characteristics.Low power consumption, high controllability, quick response, and high durability are among the major features of MR dampers. In this work we first investigate the damping characteristics of MR dampers to find out if characteristics comparable to the conventional shocks used in mountain bikes can be achieved. To this end,experimental tests were performed on an off-the-shelf MR damper. The results indicate that damping characteristics similar to the ones used in mountain bikes can in fact be achieved using MR technology.However, requirements such as small weight and wide dynamic range have to be addressed in designing a MR damper for mountain bikes. These considerations are studied in this thesis by formulating a simple design followed by a constrained optimization problem and designing the damper accordingly. Utilizing Finite element modeling and simulation tools are further utilized to fine tune and optimize the design.A prototype MR damper is fabricated after the above design steps are carried out.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

An intelligent system for energy-efficient lighting and illuminance control in buildings

Author: 
Date created: 
2014-03-04
Abstract: 

Visual comfort and energy saving are two main aspects of an intelligent lighting system. Although the modern lighting systems have been able to achieve major energy savings through different lighting control strategies, the users’ visual preferences have been generally neglected in these systems. Human perception has always been an important factor affecting the overall performance of a lighting system. Not much of the studies carried out in this field have focused on delivering the desired illuminance to the users. Not to mention that frequent changes or noticeable jumps in the output light levels could also be very annoying for the users. The contribution of this thesis is twofold: First, a robust communication framework was developed which is a major pre-requisite for deployment of any lighting system. The developed framework is responsible for facilitating the communication between various types of hardware such as motion, and light sensors, as well as light actuators in the network. Secondly, daylight harvesting, motion detection, and light level tuning strategies were explored by utilizing the developed lighting system infrastructure. In particular, a lighting control algorithm was proposed for residential and commercial use, which when integrated with a building automation system, can satisfy the visual preferences of the users while reducing the overall amount of energy usage in the system. In open-plan environments, the proposed algorithm is capable of delivering the desired light levels for each occupant. The effectiveness of the developed lighting system and the proposed control algorithm were verified by a proof-of-concept testbed and pilot implementations.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.