Faculty of Computing

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Designing of Tension Control Device to Minimize Tension Variation across Weaver's Beam
(Emerald Group Publishing Limited, 2015-08-01) Fernando, E. A. S. K; Jayawardena, T. S. S
The tension variations across the width of the weaver's beam cause uneven tension in the fabric formation zone. As a result of the tension variation, the woven fabric tends to have fabric defects, such as non-uniform fabric density and differential dye take–up at various places on the fabric. As the warp ends are continuously subjected to varying tensions, warp breakage frequently occurs. As a result, the quality of the fabric produced suffers and there is reduced loom efficiency. However, uniformity in the fabric density is crucial, especially for technical and smart textiles. In this paper, the authors have attempted to model the varyingtensions across different segments of a warp sheet under a set of assumptions and derived a linear model. Furthermore, a prototype of an automatic tension control device is instrumentedwith two different positions which are located one meter apart and allows the tension variations across the warp-sheet to be practically observed. The measured average tension shows that variations in the internal tension on different segments of the warp-sheet can be minimized or even completely eliminated over time. With the implementation of a related experiment, the authors have shown the effectiveness of this automatic tension controller and its strong implications for the industry.
Embargo
Analysis of the Dimensional Change of Woven Fabrics from Loom State to Finished State
(IEEE, 2018-05-30) Kandemulla, K. A. S. M; Maduwantha, A. R. L; Fernando, E. A. S. K; Niles, S. N; Jayawardena, T. S. S
Dimensional change of a woven fabric is a challenge in woven fabric production. The phenomenon originates from the dimensional instability of the fabric. Shrinkage is a combined result of numerous factors such as relaxation, dyeing, finishing and the effect of machinery. The significance of this problem has been investigated by several researchers, who focused mainly on the geometry of the fabric during the weaving phase (loom stage) only. To investigate the dimensional changes that occur within a particular woven structure, a number of fabric samples were sent through various finishing processes such as, washing, dyeing & finishing, under the laboratory conditions. The changes were measured either in terms of dimensional change or EPI and PPI values. Using the experimental data and theoretical analysis, a mathematical model has been developed and validated. However initially the focus is laid on plain woven fabrics and it is expected to be further extended to the other woven structures as well.
Embargo
Design and Analysis of An Anthropomorphic Two-DoF Ankle-Foot Orthosis
(IEEE, 2019-04-19) Ranaweera, R. K. P. S; Abayasiri, R. A. M; Gopura, R. A. R. C; Jayawardena, T. S. S; Mann, G. K. I
This paper proposes a two-degrees of freedom passive-dynamic ankle-foot orthosis (AFO). In view of enhancing anatomical conformity, an anthropomorphic design is proposed to minimize mechanical interferences between ankle and orthosis. The biomimetic features such as passive stabilizers and dampeners in the proposed mechanism intrinsically support the ankle and foot to maintain stability and improve shock-absorbing ability. The mobility, ranges of motion, and manipulability measures for the proposed AFO have been investigated using mathematical modeling and simulation approaches. The analysis revealed the effectiveness of the proposed AFO in meeting the complex kinematics of ankle joint compared to the predecessors. Potentially, the proposed AFO can serve as a platform to carry out research and development on robotic orthoses for the lower extremity.
Embargo
Design and fabrication of an automatic tension monitoring and regulation system for needle thread
(IEEE, 2019-07-03) Randima, L. M. L; Sandaranga, D. M. B. C; Jayawardena, T. S. S; Fernando, E. A. S. K
A matched needle and bobbin thread tensions is a major requirement of a seam and also to the quality of garment. This paper describes an attempt on the development of an automated needle thread tension regulating system for single needle lock stitch sewing machine. Historically, several experiments have been carried out to measure the thread tensions of both needle thread and bobbin thread of a lock stitch machine. However, no evident in favour of the development of a device to adjust the needle thread tension automatically. Despite a cyclic variation of the needle thread tension, a needle thread regulation system is developed to maintain an average needle tension during the cycle at a predetermined level. The developed system can be installed on an existing single needle lock stitch machine and capable of maintaining the required correct thread tension profile for sewing. The needle thread tension regulation system is a closed loop system and with a load cell as a sensing device and a geared DC motor adjusts the compression of the spring of the thread tensioner. A visual display of thread tension is indicated on a 16X4 LCD display and the required needle thread tension is set by 4x4 keypad. An Arduino board controls the electronic equipment in the system.
Open Access
An automatic air inflated tubeless safety jacket for motorbike riders
(Emerald Publishing Limited, 2021-06-22) Bulathsinghala, R. L; Fernando, S; Jayawardena, T. S. S; Heenkenda, N; Jeyakumar, S; Packiyarasa, p; Gamage, H; Wijesena, D
Purpose – Motorcycle is one of the popular modes of transport in developing countries. However, the statistics related to accidents show that motorcycles are the most vulnerable vehicles. Research studies have revealed that half of all the possible types of motorcycle injuries could be reduced or prevented using effective protective clothing. Facts and figures emphasize that this is high time to develop a safety jacket for motorbike riders. This paper aims to develop an innovative, integrated automatic air-inflated tubeless jacket to prevent major injuries in fatal accidents. Design/methodology/approach – Two accelerometers integrated near the front axle, an angle sensor and the electronic control unit (ECU) were used to detect the collision or accident. The sensors were fixed on the bike and connected with the ECU via a bluetooth device that was always at the activated stage. The fused sensors were emulated with the ECU under laboratory conditions. The trigger signal generated by the crash discriminant algorithm triggered the chemical reaction to generate N2 gas and inflate the tubeless safety jacket. Findings – Under laboratory conditions, it was found that the signal generated by the ECU unit ejected approximately 15 litres of N2 gas in volume to fill the jacket within 100 milliseconds, which was less than the approximate estimated falling time of the rider 120 milliseconds. Originality/value – The existing developments of airbag systems in motorbikes are mounted on the motorbikes’ frame, following the airbag systems in automobiles. These developments cannot fully protect the rider due to differentiation in crash dynamics and respective positions of the rider at the point of impact. Though few safety jackets and airbag vests are developed, the airbag deployment is activated when rider and motorbike separated during a collision using a tether-triggering mechanism. The authors designed the jacket so that inflation is activated not only by crash sensors but also on the fusion of multiple sensors based on a crash discriminative algorithm. The airbag deployment mechanism is incorporated with the jacket and acts as a safety jacket during a collision
Embargo
Design and Analysis of An Anthropomorphic Two-DoF Ankle-Foot Orthosis
(IEEE, 2019-04-19) Ranaweera, R. K. P. S; Abayasiri, R. A. M; Gopura, R. A. R. C; Jayawardena, T. S. S; Mann, G. K. I
This paper proposes a two-degrees of freedom passive-dynamic ankle-foot orthosis (AFO). In view of enhancing anatomical conformity, an anthropomorphic design is proposed to minimize mechanical interferences between ankle and orthosis. The biomimetic features such as passive stabilizers and dampeners in the proposed mechanism intrinsically support the ankle and foot to maintain stability and improve shock-absorbing ability. The mobility, ranges of motion, and manipulability measures for the proposed AFO have been investigated using mathematical modeling and simulation approaches. The analysis revealed the effectiveness of the proposed AFO in meeting the complex kinematics of ankle joint compared to the predecessors. Potentially, the proposed AFO can serve as a platform to carry out research and development on robotic orthoses for the lower extremity.
Embargo
Design and fabrication of an automatic tension monitoring and regulation system for needle thread
(IEEE, 2019-07-21) Randima, L. M. L; Sandaranga, D. M. B. C; Jayawardena, T. S. S; Fernando, E. A. S. K
A matched needle and bobbin thread tensions is a major requirement of a seam and also to the quality of garment. This paper describes an attempt on the development of an automated needle thread tension regulating system for single needle lock stitch sewing machine. Historically, several experiments have been carried out to measure the thread tensions of both needle thread and bobbin thread of a lock stitch machine. However, no evident in favour of the development of a device to adjust the needle thread tension automatically. Despite a cyclic variation of the needle thread tension, a needle thread regulation system is developed to maintain an average needle tension during the cycle at a predetermined level. The developed system can be installed on an existing single needle lock stitch machine and capable of maintaining the required correct thread tension profile for sewing. The needle thread tension regulation system is a closed loop system and with a load cell as a sensing device and a geared DC motor adjusts the compression of the spring of the thread tensioner. A visual display of thread tension is indicated on a 16X4 LCD display and the required needle thread tension is set by 4x4 keypad. An Arduino board controls the electronic equipment in the system.
Embargo
An automatic air inflated tubeless safety jacket for motorbike riders
(Emerald Publishing Limited, 2021-06-22) Bulathsinghala, R. L; Fernando, S; Jayawardena, T. S. S; Heenkenda, N; Jeyakumar, S; Packiyarasa, P; Gamage, H; Wijesena, D
Purpose – Motorcycle is one of the popular modes of transport in developing countries. However, the statistics related to accidents show that motorcycles are the most vulnerable vehicles. Research studies have revealed that half of all the possible types of motorcycle injuries could be reduced or prevented using effective protective clothing. Facts and figures emphasize that this is high time to develop a safety jacket for motorbike riders. This paper aims to develop an innovative, integrated automatic air-inflated tubeless jacket to prevent major injuries in fatal accidents. Design/methodology/approach – Two accelerometers integrated near the front axle, an angle sensor and the electronic control unit (ECU) were used to detect the collision or accident. The sensors were fixed on the bike and connected with the ECU via a bluetooth device that was always at the activated stage. The fused sensors were emulated with the ECU under laboratory conditions. The trigger signal generated by the crash discriminant algorithm triggered the chemical reaction to generate N2 gas and inflate the tubeless safety jacket. Findings – Under laboratory conditions, it was found that the signal generated by the ECU unit ejected approximately 15 litres of N2 gas in volume to fill the jacket within 100 milliseconds, which was less than the approximate estimated falling time of the rider 120 milliseconds. Originality/value – The existing developments of airbag systems in motorbikes are mounted on the motorbikes’ frame, following the airbag systems in automobiles. These developments cannot fully protect the rider due to differentiation in crash dynamics and respective positions of the rider at the point of impact. Though few safety jackets and airbag vests are developed, the airbag deployment is activated when rider and motorbike separated during a collision using a tether-triggering mechanism. The authors designed the jacket so that inflation is activated not only by crash sensors but also on the fusion of multiple sensors based on a crash discriminative algorithm. The airbag deployment mechanism is incorporated with the jacket and acts as a safety jacket during a collision
Open Access
Mathematical modeling of weft yarn tension in pirn winding
(Asian Transactions on Engineering, 2013-07) Fernando, E. A. S. K; Jayawardena, T. S. S
Pirn winding is an operation of winding yarn from supply yarn package onto pirns which are used for shuttle weft insertion. Firm and coherent winding tension is required to maintain in the pirn winding process to withstand the high forces produced by the deceleration of the shuttle at the end of each pick and to avoid permanent strains in yarns which will appears as fabric defects in weaving. The package size and its diameter vary due to subsequent winding of pirns. Hence the balloon effect varies and caused to change the thread tension at the winding point of the pirn. The thread tension variation is considerably significant from the first pirn wound from a package to the last pirn wound from the same if no tension controlling mechanism is devised. Placing dead weights on the disc tension controller which adds a tension to take off tension may help to compensate the yarn tension variation to some extent to combat with this problem. However, this is a stepwise manual compensation technique which needs the correct timing of compensation to avoid significant tension variations in pirn windings. The author attempted to theoretically analyze the tension variation in the yarn path of the pirn winding machine and theoretically model the tension variation with and without deadweight placement on the tensioners. Author also verified the accuracy and the validity of the model developed through the experimental results obtained at different locations along the yarn path.
Open Access
KERNEL-BASED CLUSTERING APPROACH IN DEVELOPING APPAREL SIZE CHARTS
(CiteSeerX, 2015-01) Vithanage, C. P; Jayawardena, T. S. S; Thilakaratne, C. D; Niles, S. N
With the industry revolution, apparel products also become more sophisticated moving from the basic purpose of clothing to aesthetic appeal of the garment embracing the concepts garment fitting and fashion. Garment fitting is a key technical essential for comfortable wearing. In garment fitting, size refers to a set of specified values of body measurements, such that it will provide a means for garments perfectly fit to a person. With the advent of computer software and improved data mining techniques, researchers attempted new advances in formulation of size charts with a better fit. This article suggests a kernel-based clustering approach in developing an effective size chart for the pants of Sri Lankan females. A new kernel based approach “Global Kernel K- means clustering ” was successfully deployed to cluster lower body anthropometric data of Sri Lankan females within the age range of 20-40 years. Through the proposed Kernel- based clustering method can effectively handle highly non-linear data in input space which is a key property of lower body anthropometric data and make it linearly separable in feature space without reduction in dimensions and also mathematically justified. Through this method promising results could be obtained and further clustering method was internally validated with kernel based Dunn’s index. The level of fitness of the developed size chart was also evaluated with the aggregate loss of fit factor. The proposed method has strong

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