Digital Twin Model And System Implementation Of Cold Roll Pile Dyeing Tester For Knitted Fabrics

Cold rolling pile dyeing process is a semi-continuous dyeing process between intermittent dyeing and continuous dyeing.At present,the cold-rolled pile dyeing process is mostly used for woven fabrics.The structure and properties of knitted fabrics are very different from those of woven fabrics.In the process of open-width processing,knitted fabrics are more likely to appear stretching,shrinking,curling and other phenomena under the action of tension,which will affect the quality of dyeing.Digital twinning can effectively combine information technology with physical objects,and has the characteristics of simulation,virtual-real mapping,etc.It introduces a new model for the simulation and real-time monitoring of the production process of enterprises.In this paper,the cold rolled pile dyeing machine of 1800 mm knitted fabric is studied,and the digital twin model and system realization of the cold rolled pile dyeing machine of knitted fabric are studied by using digital twin technology and taking the tension-deformation control problem as the starting point.The main research contents are as follows:1.Based on the characteristics of production control of cold rolled pile dyeing testing machine for knitted fabrics,a digital twin architecture of cold rolled pile dyeing testing machine for knitted fabrics was proposed,which combined mechanical-electrical-control-product quality multi-domain model.According to the mechanical structure of the testing machine and the configuration of the electronic control system,the digital model of the mechanical system and the control system from unit to system was established,including the mathematical modeling of the geometric entity,the behavior rule model and the electronic control mapping model,etc.,to provide model support for the digital twin system of the cold rolling pile dyeing testing machine.2.In order to study the deformation process of knitted fabrics under the action of tension,the finite element analysis models of tensile deformation and flexural deformation of weft knitted fabrics were established.The homogeneous method was used to determine the macroscopic equivalent elastic properties of knitted fabrics and calculate the constitutive model parameters of knitted fabrics.According to the different paths of knitting fabric on the test machine and the different contact conditions with the cloth guide roller,the deformation finite element model of each running section was established.The tensile stress field,deformation field and flexure deformation field of knitted fabric during continuous operation were calculated under the conditions of different speeds of 6 motors of the testing machine,and the snapshot matrix elements of the reduced order model were determined.3.In view of the long calculation time of the finite element model of knitted fabric,the digital twin model of knitted fabric deformation is established based on POD reduced order method.According to the snapshot matrix,POD reduction method is used to obtain the reduced basis matrix of field quantity,and the reduction order of finite element analysis model is realized.By using the adaptive POD method,a multi-parameter interpolation digital twin model of knitted fabric deformation is established.Compared with the finite element model,the calculation time can be shortened,and the i MAC value of the improved modal confidence criterion is between0.80 and 0.90,which has a good similarity degree of refrequency modes.4.The digital twin system of cold rolled pile dyeing tester was developed by integrating the digital twin model of electromechanical system and knitted fabric deformation.The overall structure of the system was determined,the real-time transmission mode of data stream was constructed and the communication program was written,and the information transmission between the physical equipment of the testing machine and the digital twin system was realized.According to the real-time speed of 6motors of the testing machine,the tension-deformation simulation calculation of knitted fabrics was carried out,and compared with the measured values of the tension sensor of the testing machine,a new mode of low tension control technology for open width printing and dyeing of knitted fabrics was explored.