Browsing by Author "Jayawardena, TSS"

Now showing 1 - 7 of 7

item: Thesis-Abstract
Development of an upper-limb power-assist exoskeleton robot to generate human like motion
(2015-08-28) Gunasekara, JMP; Gopura, RARC; Jayawardena, TSS
Weakness is inherently associated with ageing society. In fact, Exoskeleton robotic technology can be used to provide assistance for age society to perform activities of daily living (ADL) without depending on others. Upper limb exoskeleton robots are much suitable to perform ADL. Typically, upper limb exoskeleton robot consists of number of joints and links which are corresponding to joints and limbs of human upper limb. Further, exoskeleton robots differ from other conventional robots due to present of close interaction with wearer. In general, two types of interaction can be seen in exoskeleton robots: physical human robot interaction (pHRI) and cognitive human robot interaction (cHRI).Strengthening features of cHRI can be seen on recent developments of upper limb exoskeleton robots. However, there exists a vacuum to identify aspects of pHRI relating to performance of exoskeleton robots. The research work of this thesis is focused to design an upper limb exoskeleton robot for motion assist taking effect of kinematic redundancy. The proposed exoskeleton robot (6- REXOS) has four active degree of freedom (DOF) and two passive DOF in its kinematic chain. Two passive DOF are provided to 6-REXOS by means of flexible bellow coupling and those are positioned at wrist and elbow joint of the 6-REXOS to keep their axes parallel to each other. This configuration enhances kinematic redundancy in 6-REXOS. The effect of redundancy is verified with respect to dexterity measures, such as manipulability index, minimum singular value, and condition number. Further, manipulation of end-effector of 6- REXOS due to kinematic redundancy in operational space is presented base on manipulability ellipsoids. 4DOF kinematic model for human lower arm is proposed in thesis. Manipulability measure of human kinematic model is used to benchmark the performance of 6-REXOS. Different measures are taken into account in design of 6-REXOS to ensure smooth pHRI. Passive compliance of bellow coupling in order to reduce kinematic discrepancy as well as improve the manipulation of 6-REXOS is highlighted in this thesis.
item: Conference-Abstract
Dexterity measure of upper limb exoskeleton robot with improved redundancy
(2014-06-19) Gunasekara, MP; Gopura, RARC; Jayawardena, TSS; Mann, GKI
Exoskeleton manipulators are used for different applications in robotic field. Human motion is highly complicated and flexible; therefore obtain human like motion from exoskeleton manipulator becomes a challenge to researches in this field. This paper presents an improvement of dexterity measure as a result of adding redundancy to upper limb exoskeleton manipulator. Proposed manipulator has four degree of freedom. This takes the effect of DOF at human elbow and wrist of the upper limb. Dexterity of the manipulator is measured using manipulability index and minimum singular value. All measures are based on Jacobian of the manipulator. This four DOF manipulator is then modified by adding two more degrees of freedom to make total of six. Therefore with respect to task defined in operational space; modified exoskeleton manipulator operates as redundant. Manipulability index and minimum singular value are again determined for six degree of freedom modified exoskeleton manipulator. The effect of redundancy in order to improve the manipulation in upper limb exoskeleton robot is investigated in this study.
item: Conference-Abstract
Dexterity measure of upper limb exoskeleton robot with improved redundancy
(2015-05-07) Gunakekara, JMP; Gopura, RARC; Jayawardena, TSS; Mann, GKI
Exoskeleton manipulators are used for different applications in robotic field. Human motion is highly complicated and flexible; therefore obtain human like motion from exoskeleton manipulator becomes a challenge to researches in this field. This paper presents an improvement of dexterity measure as a result of adding redundancy to upper limb exoskeleton manipulator. Proposed manipulator has four degree of freedom. This takes the effect of DOF at human elbow and wrist of the upper limb. Dexterity of the manipulator is measured using manipulability index and minimum singular value. All measures are based on Jacobian of the manipulator. This four DOF manipulator is then modified by adding two more degrees of freedom to make total of six. Therefore with respect to task defined in operational space; modified exoskeleton manipulator operates as redundant. Manipulability index and minimum singular value are again determined for six degree of freedom modified exoskeleton manipulator. The effect of redundancy in order to improve the manipulation in upper limb exoskeleton robot is investigated in this study.
item: Conference-Abstract
Mathematical model to measure energy absorption of a sports bra
(Department of Textile and Apparel Engineering, 2023-08-31) Prasange, VSH; Liyanage, PL; Fernando, EASK; Jayawardena, TSS; Niles, SN; Nandasiri, GK; Niles, SN; Pathirana, M; Madhurangi, C
Measuring the shock absorbency of sports garments is pivotal for ensuring stability and support during exercise, minimizing injury risk in high-impact sports. It assesses a garment's capacity to absorb impact, curbing excessive breast movement and potential harm through compression, encapsulation, and structural support. This evaluation aids in predicting production outcomes and alleviating athletes' discomfort during physical activities. Prior research primarily concentrated on vertical nipple displacement using motion-capture cameras and live models, often neglecting the three-dimensional aspects of breast motion such as velocity, acceleration, and trajectory. This study introduces a novel approach using a sensor system to gather displacement, velocity, and acceleration data at specific points. It employs an artificial model to assess shock absorbency in sports garments during physical activities. The derived mathematical model, based on breast displacement data, offers insights into material and design choices prior to sample preparation. The study's findings yield invaluable insights for sports bra design and development, as well as selecting appropriate options for diverse physical activities. The authors aimed to develop a test method and mathematical model for measuring sports bra shock absorbency, addressing challenges related to cost, accuracy, and complexity. This research strives to enhance understanding and advance the evaluation of shock absorbency in sports bras, contributing to safer and more effective athletic experiences.
item:
Mathematical model to measure energy absorption of sports bra
(IEEE, 2023-11-09) Liyanage, PL; Prasanga, VSH; Niles, SN; Jayawardena, TSS; Fernando, EASK; Fernando, PR; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
Measuring the shock absorbency level of sports garments is crucial to ensure support and stability during exercise. It allows for the evaluation of the garment's ability to absorb impact and reduce the risk of injuries during high-impact sports activities. Measuring shock absorbency ensures the bra offers compression, encapsulation, and structural support, preventing excessive breast movement and potential injuries. It also helps to make predictions for the sports garment production process and helps to minimize the pain of the athletes during sports activities. The test method involves using a motion capture camera system to analyze the breast displacement level during physical activity, with the sports bra worn by a physical model. Here in this study sensor system is used to gather the displacement, velocity and acceleration data of certain points and created a new artificial model to measure the absorbency level of sports garments and to collect data during physical activities.Analysing breast displacement data creates a mathematical model that predicts material and design before sample preparation. This study helps design and choose sports bras for different activities. This research developed a test technique and mathematical model to quantify sports bra shock absorbency to address cost, accuracy, and complexity.
item: Article-Abstract
Measurement of seam puckering and influence of Its causes
Fernando, EASK; Jayawardena, TSS
Seam quality is very important aspect of any form of textile assembly using sewing. The quality of the seam is governed by the seam puckering, which mainly depends on the technological parameters of the sewing machine and fabric specifications. Though this dependency is known in qualitative aspect, very little researches have been focused to investigate the quantitative aspect of seam puckering behavior of the seams. The Phong's shading algorithm based luminosity model was developed to estimate the dimensional parameters from the image of the seam captured and, an investigation has been carried out to analyze the dimensional characteristics of puckered fabric using image processing techniques and neural networks. This objective assessment attempt goes beyond the replacement of conventional subjective puckering evaluation methods of seams and move towards the development of empirical models for the causal effects quantitatively. That is the determination of correct needle thread tension setting which is the most influential machine parameter for seam puckering, for a minimum puckering.
item: Conference-Abstract
Redundant upper limb exoskeleton robot with passive compliance
Gunasekara, jmp; Gopura, RARC; Jayawardena, TSS
Enhancing physical Human-Robot Interaction (pHRI) is an important design aspect in upper limb exoskeleton robots. The level of manipulation provided by an exoskeleton robot has a significant effect to perform daily tasks. This paper evaluate performance of a 6 degree of freedom (DoF) upper limb exoskeleton robot. The detailed mechanical design of the robot is presented with the novel features included in order to improve the pHRI. The exoskeleton robot consists of six DoF and two flexible bellow couplings are used to provide translational DoF at wrist and elbow joints. Moreover, flexible bellow couplings are positioned at specific locations in order to enhance the kinematic redundancy. The benefit of compliance due to the flexible bellow coupling at wrist joint of the robot is verified with reference to manipulability variation of the kinematic model of human lower arm.