Research And Development On Smart Seamless Garment Based On Knitted Flexible Sensors With Different Types Of Conductive Yarns

With the rapid development of apparel,electronics,medical and other fields,the demands for diversification of the same product are increasingly expanding,the emergence of smart seamless clothing is changing single function of the traditional product.As the core of smart seamless garment,the research on knitted flexible sensor is still in the early stages.At present,the research on knitted flexible sensor material was relatively simple,and there was no systematic investigation on sensing properties for knitted flexible sensors with different types of conductive yarns.The structure of existing smart seamless garment was single,almost all were based on plain plating stitch.From the appearance of it,there was a major disadvantage,but also the monitoring property was affected by it.And the appearance,portable,wearable and other aspects were still needed to be improved.Currently,the positions of knitted flexible sensor used to monitor physiological signals were design in the chest and abdomen,the signals of heartbeat and breathing may affect each other during the monitoring process.Therefore,in order to improve the measurement accuracy of the results,the development from smart seamless garment to wrist effectively separated the monitoring positions in this paper.In order to meet the demands of sensing properties for smart seamless underwear based on knitted flexible sensors,combined with jacquard plating knitting technology,different sensing sizes of knitted flexible sensors were prepared with six different types of conductive yarns.Before knitting the smart seamless underwear and wrist,whether six different types of conductive yarns meet the requirements of knitted flexible sensors should be compared and analyzed.The main contents of this paper are as follows :(1)Investigation on the sensing properties for knitted flexible sensors with different types of conductive yarns.Knitted flexible sensors prepared with six different types of conductive yarns were inserted into the seamless samples with local plating knitting technology.The sensing properties for knitted flexible sensors with different sensing sizes,such as fineness,sensitivity coefficient and repeatability,were analyzed by tensile test of fixed-extension which was used to simulate skin deformation caused by breathing and heartbeat to find out suitable conductive yarns which were knitted in smart seamless garments for monitoring the body's physiological signals.It was shown by experiments that the relationship between resistance and strain of the knitted flexible sensors with different fineness of silverplated and copper-plated conductive yarns were both linear,their sensitivity coefficient and reproducibility were suitable for knitted flexible sensors as conductive materials,and the influence of the course number was more distinct than the wale number in the design of the sensing size,the factors that influence the sensitivity coefficient of knitted flexible sensor were analyzed by orthogonal test.The significant factors affecting the sensitivity coefficient of the knitted flexible sensors with silverplated conductive yarns were as follows: the fineness of silver-plated conductive yarn,the number of courses,the interaction between the number of courses and wales,course number was more important than wale number in the design of the sensing size.(2)Knitted flexible sensors prepared with different types of conductive yarns meeting the demands of sensing properties were inserted into the smart seamless underwear and wrist with local plating knitting technology.Then,the basic stitch of smart seamless underwear,appearance and connection and arrangement of its data line were improved,to make better aesthetics and convenience in the process of wearing.(3)Smart seamless underwear based on different sensing sizes of knitted flexible sensors meet the demands of sensing properties were used to monitor the heartbeat and breathing signals.Different sensing sizes of knitted flexible sensors were analyzed the influence on the accuracy of monitoring data.For smart seamless underwear integrated the sensors with different types of conductive yarns,sensing sizes were explored to accurate data.According to the analysis of the resistance-strain relationship and the sensitivity coefficient of the knitted flexible sensor,it was found that the accuracy of monitoring data based on knitted flexible sensor was the highest when the sensitivity coefficient was about 1.(4)Smart wrists based on different sensing sizes of knitted flexible sensors meeting the demands of sensing properties were used to monitor the pulse-beating signals and analyze the influence on the accuracy of monitoring data.The higher sensitivity coefficient of smart wrists based on knitted flexible sensors with different fineness of silver-plated conductive yarns,the better accuracy of monitoring the pulse-beating signal was.The sensitivity coefficient of smart wrists based on knitted flexible sensors with copper-plated conductive yarns was smaller,but the accuracy of monitoring the pulse-beating signal was better because it avoided resistance fluctuations effectively caused by the external interference.