Research On Three-channel Digital Yarn Appearance Simulation

Under the background of "Thirteen-Five" Planning and "China Manufacturing 2025",the textile industry is pushing forward the overall industrial structure optimization,promoting intelligent and green manufacturing,in order to realize the upgrading and transformation of current textile industry.Three-channel digital spinning technology based on ring spinning can control yarn spinning with computer and produce yarn with dyed fiber which can greatly enrich yarn variety,improve production efficiency,reduce environmental pollution and adapt to the current industrial environment.The textile CAD technology is a kind of technology which uses the computer software to design and simulate the textiles,showing the characteristics of the design products.This technology can offer a graph feedback through interactive interface.This can help avoid the defects of traditional design process which usually need to make a lot of samples,greatly improve the design and production efficiency.The digital yarn has various colors,complex changes and long color change cycles.These features cause the traditional yarn simulation method cannot reflect the characteristics of digital yarn.So a textile CAD system which can adopt digital yarn simulation has become an urgent demand.In this paper,a digital blackboard simulation method for digital yarn is proposed.Based on this method,we develop a digital yarn CAD system with process design simulation and sample analysis function.This paper mainly includes the following four parts:(1)Firstly,the paper studied the digital yarn forming mechanism as the basis of the digital yarn simulation method.The rich appearance characteristics of digital yarn are derived from the real-time dynamic change of three-channel different-color roving feed ratio,compared with the traditional yarn,its greatest features are rich and diverse color,complex and changeable color circulation law,and usually having extremely long cycle.By analyzing the appearance characteristics of digital yarn,simplifying the dry of digital yarn,we can know the main components of the yarn dry appearance are the color block fragments with different size,and the size is controlled by the three-channel different color roving feed ratio.Therefore,we supposed the basic unit of simulating is the color block fragments produced by the roving channels.(2)The simulation scheme was proposed for yarn dry and hairiness respectively.in order to realize the simulation of digital yarn.To simulate yarn dry,we built a mapping model of the yarn proportioning process parameter to the digital yarn trunk simulation image,based on the color block unit.This step realized the overall appearance characteristic of the digital yarn simulation.To enrich the local characteristics of the yarn,we built the color gradient model,twist mapping model,color block size distribution model,simulated illumination model,based on digital yarn twist,color gradient characteristics,color block size distribution and so on.The result showed that these model can reflect the digital yarn dry color rules,yarn twist,and lighting effects.In order to realize the yarn hairiness simulation,we introduced the fractal theory and treated the hairiness as tree branches and lightning.Then we used the random midpoint displacement algorithm to simulate the formation of different forms hairiness.We can control the length,distribution and shape of hairiness by setting different parameters,realizing the simulation of end hairiness,ring hairiness and planktonic hairiness.(3)We designed series of comparative experiments to verify the effectiveness,stability and universality of the simulation method.The gradient yarn can fully embody the characteristics of the digital yarn,therefore we used gradient yarn as an experiment example to show details of simulation process of this method.The simulation result was good compared with the actual product which can prove the effectiveness of the method.The influence of several main model parameters on the simulation results was discussed,and the result showed that the selection range of parameters can meet the requirement of actual simulation and verified the stability of the method.We took gradient yarn as an example and discussed the simulation results under different color schemes and blending ratio,and the result verified the process adaptability of the method.Finally we used this method to simulated mixed color yarn and section color yarn,and we got a good result,which proved its adaptability.(4)We developed a digital yarn CAD system,based on the method.This system has graphical interface and can output a real-time simulation digital yarn image according to the input processing parameters.In addition,the system also has a function of digital yarn sample analysis.By scanning digital yarn sample,we can get the sample image,and use image processing technology like image preprocessing,image segmentation and color clustering to get the output of the each color and the feeding ratio.Then we can get the simulated image based on these results,realizing a further aid to digital yarn design.