Fpga-based Wound Edge Recognition For Plasma Sterilization

In view of the shortcomings of the existing large-area plasma jet sterilization device,such as fixed sterilization range,mutual interference between jets,uneven irradiation of sterilization area,large gas consumption and high cost,this paper studied the movable plasma sterilization device,and finally designed the plasma sterilization device based on FPGA wound edge recognition.The main work of this paper is as follows:Firstly,the rotary plasma sterilization device is studied as the starting point.A rotary plasma sterilization device was designed by SOLIDWORKS and manufactured based on 3D printing,with the overall size of 280×120×240mm~3.The device can control the motor,drive a single plasma jet tube to scan,and by controlling its swing Angle to adapt to different treatment areas to achieve large area sterilization.Using Escherichia coli and Staphylococcus aureus as target cells,the shortest effective sterilization time was 158s.The minimum flow rates of inactivated Staphylococcus aureus and Escherichia coli were 0.8slm and 0.6slm,respectively.In addition,the experimental results prove that compared with the array device,on the basis of realizing large area irradiation,the device not only has uniform irradiation without blind areas,but also has similar sterilization efficiency,and greatly reduces the gas consumption of external helium,thus reducing the cost.The feasibility of dynamic sterilization was verified by the rotary plasma jet device.Secondly,because the sterilization area is often irregular in reality,the movement range of the rotary plasma sterilization device is often limited to the sterilization method in the circular area,and it cannot adapt to the wound shape accurately and intelligently.Therefore,on the basis of large-scale sterilization,FPGA,a high-performance image processing platform,is further introduced to design a plasma sterilization device based on FPGA,so that it can meet the needs of different shapes of wound sterilization.Aiming at the design of plasma sterilization device based on FPGA,the mechanical structure was designed by SOILDWORKS,and the device was manufactured by 3D printing.The device can control a single plasma jet tube to carry out a good two-dimensional operation on the horizontal plane,and adjust the XY two-direction motion of the plasma jet tube according to the sterilization area of different shapes to carry out automatic,efficient and accurate plasma sterilization.Meanwhile,the distance between the plasma jet tube and the surface of the sterilized object can be adjusted in the vertical direction through the motor.Escherichia coli and Staphylococcus aureus were selected as target cells to explore the sterilization effect of the device at different speeds and flows.It was found that the ideal sterilization effect could be achieved at a speed of 2mm/s and a flow of 0.8slm,and the sterilization time cost and gas cost were the lowest on the whole.Finally,further breaking through the medium level,pig skin with similar structure to human skin was used to simulate real human wound infection bacteria,to explore the effects of sterilization effect of the device and different wound shapes and height fluctuation changes.It was found in the experiment that the optimal sterilization velocity and flow parameters originally obtained on the surface of the medium were not applicable to pig skin wounds.It was speculated that there were many microscopic folds on the surface of pig skin wounds,and bacteria were easy to hide there in the sterilization process,and sterilization was not sufficient.After the sterilization conditions were enhanced and the speed and flow rate were changed to 1mm/s and 0.8slm,the bacteria in pig skin wounds achieved the ideal sterilization effect,and the sterilization efficiency of almost the vast majority was not less than 99%.In addition,when exploring the influence of the change of the height of pork skin wound on the sterilization effect,the variable of wound fluctuation height was studied.It was found that within 5mm,with the increase of the height of wound fluctuation,the sterilization efficiency showed a trend of decrease.