Research Papers - Dept of Computer Systems Engineering
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Publication Open Access Accurate control position of belt drives under acceleration and velocity constraints(Institute of Control, Robotics and Systems, 2003) Jayawardena, T. S. S; Nakamura, M; Goto, SBelt drives provide freedom to position the motor relative to the load and this phenomenon enables reduction of the robot arm inertia. It also facilitates quick response when employed in robotics. Unfortunately, the flexible dynamics deteriorates the positioning accuracy. Therefore, there exists a trade-off between the simplicity of the control strategy to reject time varying disturbance caused by flexibility of the belt and precision in performance. Resonance of the system further leads to vibrations and poor accuracy in positioning. In this paper, accurate positioning of a belt driven mechanism using a feed-forward compensator under maximum acceleration and velocity constraints is proposed. The proposed method plans the desired trajectory and modifies it to compensate delay dynamics and vibration. Being an offline method, the proposed method could be easily and effectively adopted to the existing systems without any modification of the hardware setup. The effectiveness of the proposed method was proven by experiments carried out with an actual belt driven system. The accuracy of the simulation study based on numerical methods was also verified with the analytical solutions derived.Publication Embargo Casterless Wheelchair Robot Using Inverted Pendulum Control(IEEE, 2006-08-08) Abeygunawardhana, P. K. W; Toshiyuki, MPower assist wheelchair robot is playing a key role in the field of medical welfare robotics. But, to a certain extend, there is a setback in development due to presence of caster wheels. Hence, this paper proposes a casterless wheelchair and its control on a straight line path. That is, straight line driving of two wheel power assist wheelchair robot was proposed in this paper while keeping stability of wheelchair body itself. Balancing of wheelchair body is proposed to achieve by controlling the inverted pendulum mounted on the wheelchair. Control equations of the system are derived using Lagrange equation of motion. Two separate controllers are designed for two wheels. In addition to these two controllers, there is another controller for pendulum. Body controller is designed combining pendulum controller and wheel controller. Disturbance observer is used to cancel disturbance effects. Simulation was carried out to prove the applicability of the proposed systemPublication Embargo Self sustaining wheelchair robot on a curved trajectory(IEEE, 2006-12-15) Abeygunawardhana, P. K. W; Toshiyuki, MToday, aged population is increasing in the world, especially in developed countries. Handicapped people could not fulfill their own task without difficulties. Therefore, medical and welfare robotics has become important. Power assist wheelchair robot has been effective in this field for many years. But, to a certain extend, there is a setback in development due to presence of caster wheels. Turning, overcoming obstacles and reversing will be easy without casters. Casterless "wheelchair and its control on a straight line was presented in author's previous paper. Two wheel wheelchair robot on curved trajectory is proposed in this paper. Balancing of "wheelchair body is proposed to achieve by controlling the inverted pendulum mounted on the wheelchair. Control equations of the system are derived using Lagrange equation of motion. Body controller is designed combining pendulum controller and wheel controller. Disturbance observer is used to cancel disturbance effects. Simulation was carried out to prove the applicability of the proposed system.Publication Embargo Stability improvement of two wheel mobile manipulator by real time gain control technique(IEEE, 2007-08-09) Abeygunawardhana, P. K. WAbstract: Two wheeled mobile manipulator has significant role in industry as well as domestic environment when working space of robot is limited. On the other hand, improvement of two wheeled vehicle will explore the technology to improve welfare like wheelchair robot and industrial robots. Two wheeled mobile manipulator has been already implemented using inverted pendulum control. However, dynamic stability has to be improved further. And also, trajectory error has to be minimized. This paper propose the method to improve the stability of the robot by changing the controller gains on runtime based on the robot parameter during the running. Disturbance observer has been employed to cancel the disturbances.Publication Embargo An adaptive based approach to improve the stability of two wheel mobile manipulator(IEEE, 2007-11-05) Abeygunawardhana, P. K. W; Toshiyuki, MMobile manipulator with two wheel will play vital role when robot working with limited space. On the other hand, improvement of two wheel vehicle will explore the technology to improve welfare and industrial robots like wheelchair robot. Two wheeled mobile manipulator has been already implemented using inverted pendulum control. But system error is relatively large. Although the stability improvement using passivity theory was reported, it was not succeed with trajectory motion. Therefore, performance improvement which will be achieved through changing the PD controller gains is proposed in this paper. Disturbance observer has been employed to cancel the disturbances.Publication Open Access Analysis of Risks and Bottlenecks of a Poly Bag Manufacturing Factory -A Case Study(UNIVERSITY OF MORATUWA, 2008) Gopura, R. A. R. C; Jayawardene, T. S. SThe material prices of poly bags skyrocket to new heights and forecasters see no end to this trend. Also legal restrictions are imposed on some types of polythene products. In this situation, any entrepreneur engaging in the poly bag manufacturing process faces significant challenges. Therefore, a case study of an analysis of risks and bottlenecks of a poly bag manufacturing factory was carried out for the purpose of modeling and simulation of a poly bag manufacturing factory to improve the productivity to face the underlying challenges. This paper presents the analysis methods, and the results of the analysis are also discussed.Publication Embargo Environmental interaction of two wheeled mobile manipulator by using reaction torque observer(IEEE, 2008-03-26) Abeygunawardhana, P. K. W; Toshiyuki, MThere are so many industrial manipulators which involve in lot of task in the industry. Developing the mobile manipulator will expand the operational region of the manipulator. Moreover, two wheeled mobile manipulator will further expand the task of the mobile manipulator by being able to work in limited space and so on. However good mobile manipulator should be robust against environmental disturbance. Therefore, environmental recognition of two wheeled mobile manipulator is proposed in this paper. Reaction torque observer is implemented to recognize the environmental disturbance. Compliance control is used to compensate the environmental feedback. Experiment was carried out to show the effectiveness of the proposed method.Publication Embargo Vibration Suppression of Two Wheel Mobile Manipulator using Resonance Ratio Control(IEEE, 2008-12-02) Abeygunawardhana, P. K. W; Murakami, TTwo wheel mobile manipulator has the potential of becoming a multi-skilled robot in the field of robotics and it is already implemented by using inverted pendulum control. Centre of gravity position (COG) is controlled to achieve the balancing of robot. Since vibration of manipulator arms affect to the COG positions of the inverted pendulum, balancing of the robot deteriorates. Therefore, vibration control of manipulator arms of the mobile manipulator is proposed in this paper. Feedback signal for vibration suppression is introduced to null space of manipulator. Simulation and experiment was carried out to check the validity of the proposed method and the results prove the effectiveness of the proposed method.Publication Embargo Workspace control of two wheel mobile manipulator by resonance ratio control(IEEE, 2009-07-14) Abeygunawardhana, P. K. W; Murakami, TTwo wheel mobile manipulator has the potential of becoming a multi-skilled robot in the field of robotics and it is already implemented by using inverted pendulum control. Centre of gravity position (COG) is controlled to achieve the balancing of robot. Since vibration of manipulator arms affect to the COG positions of the inverted pendulum, balancing of the robot deteriorates. Therefore, vibration control of manipulator arms of the mobile manipulator is proposed in this paper. Feedback signal for vibration suppression is introduced at work space of manipulator. Simulation and experiment was carried out to check the validity of the proposed method and the results prove the effectiveness of the proposed method.Publication Embargo A study on a poly-bag manufacturing system preliminary analysis and simulation(IEEE, 2009-12-28) Gopura, R. A. R. C; Jayawardena, T. S. SThe material prices of poly bags increase with high degree of fluctuation and forecasters see no end to this trend. Further, legal restrictions imposed on certain types of polythene products adversely affect the demand. In the light of the above, entrepreneurs of the poly bag manufacturing face many challenges. In this study, an analysis and a simulation of a poly bag manufacturing system were carried out to improve the productivity to face the underlying challenges. This paper presents analysis, modeling and simulation methods of the system. In addition, a risk prioritization method was proposed at the preliminary analysis and also a simulation tool was developed.Publication Embargo Vibration suppression of two-wheel mobile manipulator using resonance-ratio-control-based null-space control(IEEE, 2010-03-01) Abeygunawardhana, P. K. W; Murakami, TA two-wheel mobile manipulator has the potential to become a multiskilled robot in the field of robotics, and it is already implemented by using inverted pendulum control. The center of gravity (COG) position is controlled to achieve the balancing of the robot. Since the vibrations of manipulator arms affect the COG positions of the inverted pendulum, balancing of the robot deteriorates. Therefore, the vibration control of manipulator arms of the two-wheel mobile manipulator is proposed in this paper. The virtual double-inverted pendulum is modeled using a “4-DOF” manipulator, and it is controlled in work space and null space. Resonance ratio control is utilized for vibration-suppression control. The resonance ratio of a system can be determined arbitrarily by the feedback of reaction torque, and reaction torque observers are implemented for each and every manipulator motor. The feedback signal for vibration suppression is introduced to the null space of the manipulator. Simulations and experiments were carried out to check the validity of the proposed method, and results prove the effectiveness of the proposed vibration controller.Publication Embargo Self-sustaining control of two-wheel mobile manipulator using sliding mode control(IEEE, 2010-03-21) Abeygunawardhana, P. K. W; Defoort, M; Murakami, TTwo wheel mobile manipulator has the potential to become multi-skilled robot in the field of robotics engineering and it is already implemented by using inverted pendulum control. Centre of gravity position is controlled to achieve the balancing of robot. Due to the unbalanced nature and the nonholonomic property of the two-wheel mobile manipulator, balancing is challenging task. On the other hand sliding mode control is a good candidate to address the nonlinear/under actuated system. This paper presents the control methods for balancing of two-wheel mobile manipulator. This paper proposes a novel second order sliding mode controller using twisting algorithm, disturbance observer and dynamics of double inverted pendulum. Dynamics of double inverted pendulum is used to design the control equation of sliding mode controller. Twisting algorithm is used to design the control input. Disturbance observer is compensated model uncertainties and external disturbances. Posture of two wheel mobile manipulator can successfully stabilized by this novel controller.Publication Open Access Control of two wheel mobile manipulator on a rough terrain using reaction torque observer feedback(Library of Science, 2010-04-01) Abeygunawardhana, P. K. W; Murakami, TThe mobile manipulator has the potential to become an efficient industrial robot due to its mobility and dexterity. Moreover, it has expanded the operational area of the mobile manipulator due to its ability to work in a limited space. However, adaptability to unknown environments has still not been developed to date. Therefore, adaptation of the mobile manipulator for unknown environments especially for rough/irregular terrain is discussed in this paper. Information about the environment, a key factor when aiming for compliance with an unknown and/or unstructured environment, was collected using a reaction torque observer. In order to adapt to the environment, compliance control was applied to the mobile manipulator. In this paper, we present a novel control strategy we have developed that can deal with unknown environments through the effective use of inverted pendulum control. Simulation and experiments were carried out to ensure the validity of the proposed method. The method could be confirmed as effective according to the results obtained.Publication Embargo Trainko: poster abstract: train arrival time prediction system for Sri Lanka(acm.org, 2011-04-11) Jayawardena, A. N; Sachith, K; Wijekoon, JTransportation system is a massive enterprise with substantial direct and indirect effects on economic growth of a country, and train system is playing a major role of the transportation system. However, the train system in Sri Lanka is usually late and the passengers come to the stations without knowing the train arrival time, whereas the passengers waste their valuable time at the train station waiting for the trains. To this end, this paper proposes to the smarten Sri Lankan the train system by predicting the time a train reaches to its upcoming stations and sending the notifications to the subscribers about the arrival time to their stations. Subscribers then can reach their station whenever the train is reaching to the station or they can use any other means of transportation if the train is late.Publication Embargo An adaptive routing algorithm for Cognitive Packet Network infrastructure based on neural networks(IEEE, 2011-08-16) Madubashitha, D. K. D; Wijesinghe, W. M. S. S; Kamaladiwela, K. A. S. R; Ranaweera, M. G. P; Wijekoon, J; Abeygunawardhana, P. K. WThis paper examines the possibility of introducing an intelligent routing protocol to the Internet, based on the Cognitive Packet Network (CPN) architecture with respect to the Quality of Service (QoS) delivered to the end users. In the present with increasing populations of countries it is clear that present infrastructure does not hold the sufficient capacity to deliver the expected level of service to the end users. Since there is an eminent need for a solution for improving the QoS in the Internet, this research focuses to provide a new network architecture which would improve the QoS, provide reliable and efficient service which can fulfill the ever growing Internet usage demand. This is achieved through a new network architecture known as CPN which is based on the basis of providing the best and user desired QoS. The main underlying technology behind the CPN will be a neural network. The neural network will be learning the changes in the network and adapt to the situation through the knowledge gathered. The packets will collectively learn about the network thus the load on the routers will be minimized. This mechanism completely replaces the need of a routing table thus making routing far more efficient when comparing to current routing protocols like Open Shortest Path First (OSPF). Final outcome of the research is coming to the conclusion that the future of the Internet is with the neural network based intelligent, dynamically adapting and learning CPN infrastructure instead of current packet switched network.Publication Embargo The advanced remote PC management suite(IEEE, 2011-08-16) Wijekoon, J; Wijesundara, M; Dassanayaka, T; Samarathunga, D; Dissanayaka, R; Perera, DDeveloping a system that helps system administrators to perform their administration task more effectively and efficiently is of great importance to reduce downtime, cost and man power requirement. The Advanced Remote PC Management Suite facilitates centralized management of PC infrastructure employing the Intel Active Management Technology (AMT). This technology enables the system administrators to monitor and manage computers via a dedicated channel regardless of whether the computer is powered on. This is known as Out-of-Band (OOB) management. Currently AMT is available in Desktops and Laptops with The 2nd generation Intel Core vPro processors. Using features of AMT, the The Advanced Remote PC Management Suite provides a real-time and intelligent asset management facility in addition to monitoring and administration capabilities. The system also features automated operating system deployment and centralized disk cloning mechanisms. It is also possible to isolate any computer in the network using the system, during incidents such as virus infections. Therefore, this system is able to drastically reduce the number of desk-side-visits by system administrators to setup and troubleshoot PCs in large enterprise networks.Publication Embargo An empirical study on slow and limited adoption of internet banking by Sri Lankan customers(IEEE, 2011-08-16) Weerasekara, S; Abeygunawardhana, P. K. WUsage of internet is rapidly increasing in Sri Lanka. However, usage of internet banking is very slow compared to increase of internet users. This study will focus on four main possible areas which may effect to slow adaptation of Internet Banking as Awareness & Knowledge of Internet Banking, Perceived Characteristics of Internet Banking, Consumer Resistance to Change, Legal Support and IS Security. Based on the data gathered, these 4 conditions are tested using statically analysis method.Publication Embargo An Empirical Study on Slow and Limited Adoption of Internet Banking By Sri Lankan Customers(IEEE, 2011-08-16) Abeygunawardhana, P. K. W; Weerasekara, SUsage of internet is rapidly increasing in Sri Lanka. However, usage of internet banking is very slow compared to increase of internet users. This study will focus on four main possible areas which may effect to slow adaptation of Internet Banking as Awareness & Knowledge of Internet Banking, Perceived Characteristics of Internet Banking, Consumer Resistance to Change, Legal Support and IS Security. Based on the data gathered, these 4 conditions are tested using statically analysis method.Publication Embargo An adaptive routing algorithm for Cognitive Packet Network infrastructure based on neural networks(IEEE, 2011-08-16) Madubashitha, D. K. D; Wijesinghe, W. M. S. S; Kamaladiwela, K. A. S. R; Ranaweera, M. G. P; Wijekoon, J; Abeygunawardhana, P. K. WThis paper examines the possibility of introducing an intelligent routing protocol to the Internet, based on the Cognitive Packet Network (CPN) architecture with respect to the Quality of Service (QoS) delivered to the end users. In the present with increasing populations of countries it is clear that present infrastructure does not hold the sufficient capacity to deliver the expected level of service to the end users. Since there is an eminent need for a solution for improving the QoS in the Internet, this research focuses to provide a new network architecture which would improve the QoS, provide reliable and efficient service which can fulfill the ever growing Internet usage demand. This is achieved through a new network architecture known as CPN which is based on the basis of providing the best and user desired QoS. The main underlying technology behind the CPN will be a neural network. The neural network will be learning the changes in the network and adapt to the situation through the knowledge gathered. The packets will collectively learn about the network thus the load on the routers will be minimized. This mechanism completely replaces the need of a routing table thus making routing far more efficient when comparing to current routing protocols like Open Shortest Path First (OSPF). Final outcome of the research is coming to the conclusion that the future of the Internet is with the neural network based intelligent, dynamically adapting and learning CPN infrastructure instead of current packet switched network.Publication Open Access Analysis, Modeling and Simulation of a Poly-Bag Manufacturing System(Scientific Research Publishing, 2012-05-24) Gopura, R. A. R. C; Jayawardane, T. S. SThe cost of raw material of poly-bags increases and fluctuates with an unpredictable trend. Further, legal restrictions imposed on some types of polythene products adversely affects for the demand. In this context, entrepreneurs engaging in poly-bag manufacturing face major challenges. With the purview of optimizing the poly-bag manufacturing process, authors attempted to analyze, model and simulate the poly-bag manufacturing process in the light of posed challenges. This paper presents preliminary analysis, modeling and simulation strategies of a poly-bag manufacturing system. In addition, a risk prioritization method is proposed in the preliminary analysis and also a simulation tool is developed.