Research On Weft Skew Detection And Weft Adjustment Of Camera Weft-straightening Machine

The correction of weft skew is an indispensable step in the heat setting process of textile finishing.This link needs to be completed with the help of the weft straightening device.The working process of the weft straightening device mainly includes two parts: weft skew detection and weft correction.At present,photoelectric detection method is widely used to detect the weft skew of the fabric.However,due to the limited detection ability of photoelectric sensor for thick fabric,there are many problems such as maintenance difficulties,etc.,it is a good alternative to use the camera method to detect the weft skew of the fabric.In this paper,the detection method of weft skew is studied by using weft skew image,and then the improvement scheme of weft straightening device and the calculation method of adjustment amount of weft straightening roller are studied by establishing simulation database.Finally,the mathematical model is established to study the control method of weft straightening system.The main work of this paper is summarized as follows:1.Design a detection method of fabric weft skew.First of all,the method of fabric skew detection based on the ideal fabric image is studied and summarized.Then,aiming at the problem that the fabric itself may contain flaws and the fabric image may have noise or uneven illumination,and the detection accuracy is not high under the non ideal condition,a correction method of fabric image under uneven illumination and a skew detection method based on pixel statistics are designed.Finally,the validity and feasibility of the detection method are verified by experiments.2.The improved scheme of weft straightening device and the calculation method of weft skew deviation are put forward.First of all,through the research on the basic structure of the weft straightening device and the basic principle of the weft straightening,it is found that the existing weft straightening device has limitations for the correction of double bow weft and other types of weft skew,and the improvement scheme of adding two kinds of roller type is proposed.Then,according to the relevant national standards for weft skew detection,the common characteristics of weft are summed up,and the simulation database of weft shape is established.Finally,a classified interpolation method is designed to restore the weft shape of the fabric by using the established simulation database,and the adjustment amount of the weft straightening roller and the weft skew deviation are obtained by using the least square method.The feasibility of the method is verified by experiments.3.Establish the mathematical model of the weft straightening device,and design the controller of weft straightening.Firstly,the control system of weft straightening is analyzed,and the control process of weft straightening device is studied.Then,the motor model,straightening device model and fabric model of the weft straightening device are established respectively,and PID controller is designed to control the weft straightening control system.Finally,the rationality and effectiveness of the control scheme are illustrated by simulation experiments.