Research Papers - Department of Mechanical Engineering
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Publication Open 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. HIn 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.Publication Embargo 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, NThis 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.Publication Open Access Sustainable Energy Options for Sri Lankan Transport sector(National Energy Symposium 2019, 2019) Fernando, G. L; Ruzaik, M. A; Liyanage, M. HTransport sector of Sri Lanka accounts for 29% of total energy consumption and almost half of greenhouse gas (GHG) emissions in Sri Lanka. This study is to investigate the possible sustainable energy options for the transport sector. Sri Lankan transport sector is modelled using the Asia Pacific Integrated/Endues (AIM Endues) model for the planning horizon from 2015 to 2045. This study analyses four countermeasures along with the business as usual (BAU) scenario. The first countermeasure scenario is promoting residential solar electricity for electric vehicles. Other three scenarios modelled with 20%, 30% and 40% subsidy for electric and hybrid vehicles. Out of the four scenarios, promoting residential solar electricity for electric vehicles is the most effective countermeasure as it could reduce the transport sector energy consumption by 16.4 Mtoe and CO2 emissions by 35% in 2045. At the current vehicle and electricity prices, providing 20% subsidy will not be effective as 30% and 40% subsidies in achieving significant reduction in energy consumption and CO2 mitigation Sri Lankan transport sector.Publication Embargo Optimization of controller gains for FPGA-based multivariable motion controller using response surface methodology(IEEE, 2015-05-03) Sekaran, H. P; Liyanage, M. H; Krouglicof, NField Programmable Gate Arrays (FPGA) have become increasingly popular in recent years for control applications. Using contemporary FPGA technology, a powerful virtual processor can be synthesized and integrated with custom hardware to create a dedicated controller that outperforms conventional microcontroller and microprocessor based designs. The FPGA based controller takes advantage of both hardware features and virtual processor technology. This study details the development of a cascaded type PD controller for an inverted pendulum system implemented on a single FPGA device. The controller includes a hardware based implementation of the IO modules including quadrature decoders/counters and a Pulse Width Modulation (PWM) controller for the motor driver. The NIOS II processor was synthesized to implement the cascaded PID controller algorithm. This study also proposes a novel method for obtaining the optimal controller gains for the system. It uses the Central Composite Design (CCD) in Response Surface Methodology (RSM) for obtaining these gains. A classic inverted pendulum system was selected to demonstrate the applicability of the proposed approach. The gains provided by the RSM were verified experimentally to validate the proposed controller tuning method.Publication Embargo Energy and Environmental Implications of Green House Gas Mitigation Policies in the Transport Sector of Sri Lanka(IEEE, 2018-10-24) Fernando, G. L; Liyanage, M. H; Samarasekara, G. NThis study analyzes the greenhouse gas mitigation policy options for the transport sector in Sri Lanka. It was carried out through the Asia-Pacific Integrated Assessment Model (AIM/Enduse), which is a bottom up type least cost optimization framework. A business as usual scenario and four alternative mitigation policy options were considered in this study. These policy options include two scenarios with 100 $/tonCO 2 , 500 $/tonCO 2 carbon tax, a subsidy scenario with tax rebates for electric, hybrid vehicles and a scenario which promotes pubic transport. The results show that the transport sector energy consumption is expected to increase from 5 Mtoe in 2015 to 19.5 Mtoe in 2045. The CO 2 emissions are expected to increase from 15 Mton in 2015 to 58 Mton in 2045. Out of the four scenarios, promoting public transport was most effective as it could reduce energy consumption by 52% and reduce CO 2 emissions by almost 36% in 2045. At current electricity prices and other costs, electric vehicles are not found to be economical in the analysis.Publication Embargo A single time scale visual servoing system for a high speed SCARA type robotic arm(IEEE, 2014-05-31) Liyanage, M. H; Krouglicof, NA high speed image based visual servoing (VS) technique is developed in this study for a Selective Compliant Assembly Robotic Arm (SCARA) manipulator with rotary hydraulic actuators. This study has developed a 2D position measuring system which comprise a high speed camera with a position sensitive detector as the image sensor. The input output interface and the controller for the VS system was implemented using a field programmable gate array (FPGA) providing a single chip solution for the embedded system. This camera was capable of providing position measurements of the end effector (EE) with an accuracy of up to 0.95 mm at a frequency of 1340 Hz. The proposed control strategy produced a better tracking performance with an EE payload of 12 kg with speeds of up to 1.3 m/s.Publication Embargo High speed electro-hydraulic actuator for a scara type robotic arm(IEEE, 2010-10-18) Liyanage, M. H; Krouglicof, N; Gosine, RThis study details the development of a high performance servo-hydraulic actuator for a Selective Compliant Assembly Robotic Arm (SCARA). The arm is intended for high speed food processing applications; specifically on-line poultry deboning. The system is mathematically modeled and simulated. Based on the simulation results, the hydraulic actuators are sized for optimal performance. A prototype actuator is subsequently designed, manufactured and experimentally evaluated. The tests results demonstrate that the prototype actuator is capable of producing unprecedented torques and associated accelerations relative to its size and mass. Comparable performance is not feasible with contemporary electrical actuators of similar size.Publication Embargo Development and testing of a novel high speed SCARA type manipulator for robotic applications(IEEE, 2011-05-09) Liyanage, M. H; Krouglicof, N; Gosine, RThis paper proposes using servo hydraulics for high speed robotic manipulation. It details the development of a novel double vane rotary type actuator custom designed for use in a Selective Compliant Assembly Robotic Arm (SCARA). The system, which is mathematically modeled and simulated, consists of an electro-hydraulic servo valve, double vane rotary actuator, manipulator and a controller. Based on the simulation results, hydraulic actuators were sized for optimal performance. A prototype of the proposed manipulator was built and tested. The test results show that the proposed actuator is capable of reaching torques of up to 860 Nm. The end effector of the manipulator is capable of reaching average velocities in excess of 2.7 ms -1 with a payload capability of 5.3 kg. Comparable performance is not feasible with contemporary SCARA type robots with electric motors.Publication Embargo Effects of carbon tax on greenhouse gas mitigation in Thailand(Taylor & Francis Group, 2008-01-01) Shrestha, R. M; Pradhan, S; Liyanage, M. HThis study analyses energy system development and the associated greenhouse gas emissions in Thailand under a reference case and three different carbon tax scenarios during 2013–2050 using a bottom-up cost-minimizing energy system model based on the Asia–Pacific Integrated Assessment Model (AIM/Enduse) framework. It considers the role of the renewable energy technologies as well as some emerging GHG-mitigating technologies, e.g. carbon capture and storage (CCS) in power generation, and GHG reduction in the country, and found that the power sector will play a major role in CO2 emission reduction. Under the carbon tax scenarios, most of the CO2 emission reduction (over 70%) will come from the power sector. The results also indicate the very significant potential for CO2 emission reduction through a significant change in the transport system of the country by shifting from low-occupancy personal modes of transport to electrified MRTS and railways.Publication Embargo Design and control of a high performance SCARA type robotic arm with rotary hydraulic actuators(IEEE, 2009-05-03) Liyanage, M. H; Krouglicof, N; Gosine, RThis study proposes a selective compliant assembly robotic arm (SCARA) with two revolute joints for poultry deboning. The joints of the arm are based on two high performance rotary type hydraulic actuators. These actuators are operated by servo valves, which control hydraulic fluid flow and direction. A PID based independent joint control system is considered for controlling the position of each joint. The system was modelled using the MATLAB-SIMULINK toolbox. The simulation results show that the arm was capable of covering a work envelope of 0.9 m times 0.9 m, reaching controlled velocities of up to 7.5 m/s with an average of 5.8 m/s. Obtaining such high speeds and torques would be a difficult task with electrical actuators of the capacity as the hydraulic counterparts considered here.