Research Papers - Department of Mechanical Engineering

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Start date: 2010End date: 2019

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    Robotic gripper design to handle an arbitrarily shaped object by emulating human finger motion
    (IEEE, 2015-08-24) Welhenge, A. M; Wijesinghe, R. D; Rajakaruna, R. M. T. P
    Controlling a robotic gripper to handle objects in different sizes and shapes in real-time is a complex task. The challenge is to adapt and position the gripper according to a target object. In this work, by considering a three fingered robotic gripper with a finger structure similar to that of human finger, we study the positioning of fingers in a gripper in the two dimensional plane. Using an inverse kinematic model for a pulley based underactuated mechanical finger, we derive a region of reach in the plane of the finger. Simulations demonstrate the limits of reach under different conditions. This can be used to derive the positioning of each finger, as well as in path planning to control the reach of the gripper.
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    PublicationOpen Access
    Making Realistic Predictions on Building Energy Performance through Coupled Energy Simulation and Computational Fluid Dynamics
    (National Energy Symposium, 2015-11-20) Bandara, R. M. P. S; Attalage, R. A; Fernando, W. C. D. K
    Buildings account for nearly 40% of the global energy consumption and hence presently high emphasize is made on improving the energy performance of buildings. Energy Simulation (ES) is the most widely used method in predicting the energy performance of buildings during the conceptual stage. However, it is observed that Energy Simulation tools show certain inherent deficiencies in predicting the energy performance of buildings. The said tools do not have the capacity to model air circulation through the building space explicitly. Energy Simulation tools mainly rely on the simplifying assumption that air within a thermal zone of a building is well-mixed. Furthermore, convective heat transfer coefficients of building surfaces are calculated using set empirical correlations. Hence, ES tools often find it difficult to make realistic predictions on energy performance of buildings. The literature also reveals that most Energy Simulation tools under-predict energy consumption in buildings, especially under sunny conditions. On the other hand, Computational Fluid Dynamics (CFD) tools are capable of predicting the indoor flow field comprehensively. However, CFD simulations need to be provided with the corresponding boundary conditions of the computational domain, which are readily available in the Energy Simulation approach. On this basis, the paper explains how Energy Simulation can be coupled with Computational Fluid Dynamics in predicting the energy performance of an actual building design more accurately through complementary data exchange between the tools. The analysis uses EnergyPlus 8.0 and Ansys Fluent 6.3 as the tools for conducting Energy Simulation and Computational Fluid Dynamics respectively. MATLAB R2012a establishes the coupling platform. The study shows that the coupled scheme predicts considerably higher energy consumption for the building design compared to that given by the conventional Energy Simulation using EnergyPlus.
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    A techno-economic analysis for an integrated solar PV/T system for building applications
    (IEEE, 2016-12-16) Jayasuriya, W. J. A; Athukorala, A. U. C. D; Perera, A. T. D; Sirimanna, M. P. G; Attalage, R. A
    This study presents a techno-economic assessment about an integrated energy system based on hybrid Photovoltaic/Thermal (PV/T) panels to cater the energy demand for an apparel manufacturing application. The energy system consists of PV/T panels, H2 storage, electrolyzer, fuel cell and a latent heat thermal storage. A computational model (energy flow model combined with an economic model) is developed to assess the performance of the system. The computational model is simulated on hourly basis for a selected set of representative days of the year. The responses of energy storage and local grid according to demand variations of the application are evaluated subsequently considering the economic aspects. A novel dispatch strategy is introduced to charge and discharge energy storage based on the real time pricing of the grid. The response of local grid with the changes in system configuration is analyzed in the study. The potential of harvesting energy from integrated PV/T systems is emphasized by comparing the grid interaction with the in different climatic conditions is through case studies for different geographic locations. Results obtained from the study demonstrate the feasibility of integrated energy systems based on PV/T.
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    Development of multi-sensory feedback system for building automation systems
    (IEEE, 2017-10) Basnayake, B. A. D. J. C. K; Amarasinghe, Y. W. R; Attalage, R. A; Jayasekara, A. G. B. P; Devinda, M. G. K
    Under this research, the multi-sensory feedback system has been developed utilizing commercially available MEMS based and miniaturized sensors for building automation systems. This system consist of non-contact infrared thermal array sensor based occupancy identification / localization system and self-floor locations categorization system with an environmental monitoring system. Further, it has smart realtime energy monitoring system which capable to identify the load devices and their status while operation. The entire system is capable of obtaining quantitative values of this sensory information and applied for the development of more convenient and energy efficient automation in building premises. The implemented system was tested and validated using fuzzy logic based building automation controller via the wireless network.
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    A model for analyzing the thermal performance of roof configurations with flat inclined surfaces
    (Elsevier, 2016-03-15) Sirimanna, M. P. G; Attalage, R. A
    The development of a thermal model, followed by a generalized computational tool that analyses thermal performance of roofs with four inclined surfaces and a ceiling by considering dynamic environmental and operating conditions, changes of roof geometry and materials is presented here. Roof elements are analyzed based on finite-volume method with implicit formulation. View factors of roof enclosures are calculated numerically. Experimental results, obtained for six actual building roofs under tropical climatic conditions of Sri Lanka, indicated that the thermal model is capable of replicating the actual temperature profiles with an average accuracy of 1.1 °C. Ceiling temperature of common roofs were found to be 10 °C above the ambient temperature, which could even rise up to15 °C in hot days. The model was successfully used to compare roofs and quantify the thermal effects of different parameters. For instance, changes in geometrical parameters led ceiling temperature to change by 5 °C, highlighting the importance of roof geometry. Out of the widely used three roofing materials in Sri Lanka, clay tile roofing has showed the best thermal performance. Compared to clay tiles, asbestos and steel roofing can have a maximum ceiling temperature rise of 4 °C and 6 °C, respectively.
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    Multi Objective Optimization of Lifecycle Cost, Unmet Load, and Renewable Energy Capacity for an Expansion of Existing Standalone Internal Combustion Generator (ICG) Systems
    (Elsevier, 2011-01-01) Perera, A. T. D; Attalage, R. A
    This paper presents, for the first time, the application of the strength Pareto evolutionary algorithm to the multi-objective design of isolated hybrid systems, minimising both the total cost throughout the useful life of the installation and the unmet load. For this task, a multi-objective evolutionary algorithm (MOEA) and a genetic algorithm (GA) have been used in order to find the best combinations of components for the hybrid system and control strategy. Also, a novel control strategy has been developed and it will be expounded in this article. As an example of application, a PV–wind–diesel system has been designed, obtaining a set of possible solutions (Pareto set) from which the designer can choose those which he/she prefers considering the costs and unmet load of each. The results obtained demonstrate the practical utility of the design method used.
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    Occupancy identification based energy efficient Illuminance controller with improved visual comfort in buildings
    (IEEE, 2017-05-29) Basnayake, B. A. D. J. C. K; Amarasinghe, Y. W. R; Attalage, R. A; Jayasekara, A. G. B. P
    Under this research Smart energy efficient and visual comfort lighting system has been developed based on the presence of occupancy and occupancy localization information. The developed system consist of non-contact occupancy identification system, wireless sensor network, and wireless light intensity control device. The controller is constructed on a fuzzy logic based closed loop controller developed on a single board computer powered by 900MHz quad-core ARM Cortex-A7 CPU. Lighting is an important factor in maintaining the visual comfort in a living premise. According to literature, the lighting consumes about 40% of total electricity consumption in a building. Since lighting energy requirement contains a larger share of energy demand any saving from that demand will result in a reduction in areas of energy wastage, negative impact to the environment and the cost to the consumers and so on. The results of the experiment indicate that the improvement of visual comfort and enhanced energy performance by avoiding of unwanted visual comfort level in a living premise.
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    Smart solar tracking and on-site photovoltic efficiency measurement system
    (IEEE, 2016-04-05) Basnayake, B. A. D. J. C. K; Jayathilaka, W. A. D. M; Amarasinghe, Y. W. R; Attalage, R. A; Jayasekara, A. G. B. P
    On-site photovoltaic efficiency data is a valuable asset during a process of predicting photovoltaic potential. Not just the solar power output, but also the ambient conditions and panel temperature should be measured for a better and convinced results. Due to the unavailability of on-site data, erroneous conclusions have been made after various prediction methods. Smart solar tracking and on-site photovoltaic measurement system is proposed as a novel tool to be used in solar potential predictions which can measure and log on-site solar data. This device is capable of measuring and logging available solar power together with ambient measurements such as light intensity level, ambient temperature and humidity level and panel temperature. Measured data will then be stored in an internal memory card and will be available at any moment. Integrated wireless communication module will enable remote log-in and control of the device. Computer based Graphical User Interface (GUI) software application enables the remote access to the gathered data and optimization of its operation.
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    PublicationOpen Access
    A QUADCOPTER WITH AUTOMATED TAKE-OFF AND LANDING ON MOBILE ROBOT PLATFORM
    (SHEFFIELD HALLAM UNIVERSITY ENGINEERING PROGRAM, 2016-12) Sandaruwan, B. A. S; Mithun, S; Rathnayake, R. M. K. M; Liyanage, M. H
    In this thesis, a controller is designed for an off the shelf quadcopter to give it the ability to autonomously takeoff, hover at a given altitude, follow and land on a mobile robot platform. This is a small part of a much bigger system which is a quadcopter and a mobile robot combined fully autonomous surveillance system. This system has the ability to navigate and complete a given task without any human interaction. Different types of sensor are used to determine the position of the quadcopter in 3D space. A PID controller is implemented to keep the quadcopter at a given altitude. Different types of sensors and technologies were used to achieve our target. A discrete PID controller will be used to hold the altitude of the quadcopter. Real-time image processing is used to determine the position of the quadcopter relative to the mobile robot platform. An ideal quadcopter simulation and a 3D simulation of the task is done to understand in detail how a quadcopter works and how to controller it the way we desire. Kalman filter is used to produce accurate and precious angular data of the quadcopter. The project is separated into several parts and divided among all the members of the group. The simulation of the complete system and the implementation of the takeoff, altitude holding and landing algorithms for the test system are done by me. Determining the position of the quadcopter using image processing and design and implementation of the Mobile robot platform is done by Rathnayake R.M.K.M. Implementation of Kalman filter to be used with Gyro and accelerometer sensors and the simulation of an ideal quadcopter model in Matlab is done by S. Mithun.
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    An Embedded System for a High-Speed Manipulator With Single Time Scale Visual Servoing
    (American Society of Mechanical Engineers, 2017-07-01) Liyanage, M. H; Krouglicof, N
    This study presents the development of an embedded system for controlling a high-speed robotic manipulator. Three different types of controllers including hardware proportional derivative (PD), software PD, and single time scale visual servoing are considered in this study. Novel field programmable gate array (FPGA) technology was used for implementing the embedded system for faster execution speeds and parallelism. It is comprised of dedicated hardware and software modules for obtaining sensor feedback and control signal (CT) estimation, providing the control signal to the servovalves. A NIOS II virtual soft processor system was configured in the FPGA for implementing functions that are computationally expensive and difficult to implement in hardware. Quadrature decoding, serial peripheral interface (SPI) input and output modules, and control signal estimation in some cases was carried out using the dedicated hardware modules. The experiments show that the proposed controller performed satisfactory control of the end effector position. It performed single time scale visual servoing with control signal updates at 330 Hz to control the end effector trajectory at speeds of up to 0.8 ms1 . The FPGA technology also provided a more compact single chip implementation of the controller.