Design And Implement Of The Photoelectric Detection System For Yarn Defects

China has always been a traditional large textile country and textile industry plays an important role in China's national economy.However,due to lack of innovative textile technology,most textile fabrics products made in China belong to medium level or lower level products.In this thesis,the photoelectric detection methods for yarn deflects are intensively studied.Yarn deflects such as breaking defects,thickness defects,flat defects and color defects are addressed detailed.The main work of this thesis can be summarized as follows:Firstly,the detecting light path,signal processing circuit and MCU program were designed,as well as the PCB of each modular.For detecting the breaking defects of yarn,the green laser light source and photoelectric sensor were located at two sides of the yarn.OPT101 chip was adopted as by the photoelectric system.For detecting the thickness deflects and the broken deflects,the light path and circuit are the same as the breaking defects.For detecting the flat defects,the green laser light source was located in horizontal direction,and the optical signal was received by photoelectric sensor on the other side of the yarn through green filter.In the vertical direction,the red laser light source was used to irradiate the yarn,and the optical signal was received by the photoelectric sensor on the other side of the yarn through the red filter.The photoelectric sensor was the same as that of for the breaking defects.Four white LEDs were used in the lighting circuit for color defects of yarn.The RGB color information of yarn was measured by TCS230 chip which was used to test the reflected light signal of yarn.STC15W4KS234 was adopted as the core chip of the system.Secondly,an integrated detection scheme for four kinds of yarn defects as well as the hardware and software design and implementation of the scheme were also presented.The main idea of integrated detection scheme was to make the optical circuit as simple as possible without affecting the performance.The red laser,green laser and white LED were used as light source.Red filters and green filters were used to filter light source to prevent the interference of light source.OPT101 was used as the core chip for deflecting the breaking defects,thickness defects,flat defects of the yarn.TCS230 was chosen as the color sensor for color defects.STC15W4KS234 was used as the processing chip of the system.In the MCU program,the horizontal photoelectric sensor and the vertical direction photoelectric sensor performed the ADC conversion,and the color sensor sampling was done finally.Thirdly,the integrated detection scheme for the four kinds of yarn deflects were tested.A novel detecting system with three light sources and three sensors were built.The test object was a millimeter grade yarn with located in the static environment of the detecting system of yarn defects.The broken deflects,thickness deflects and flat deflects were measured according to the voltage value,and the yarn color deflects was measured according to the RGB value.Finally,the four kinds of yarn deflects can be detected by the 0.2 mm yarn successfully.