The widelywidely--used online mixing system has a small range of mixture ratio and a detection problem at small flow ratio used online mixing system has a small range of mixture ratio and a detection problem at small flow ratio of pesticide. This paper developed an online of pesticide. This paper developed an online--mixing system, which mixed pesticide into carrier directly.mixing system, which mixed pesticide into carrier directly.The The pesticide were injected to the mixer from pesticide tang through a piston pump, witch controlled by stepper pesticide were injected to the mixer from pesticide tang through a piston pump, witch controlled by stepper motor. A solenoid valve was used to control water flow into the buffer tank; the water level of the buffer tank was motor. A solenoid valve was used to control water flow into the buffer tank; the water level of the buffer tank was controlled using two liquid level sensor feedback. The water flow rate of the spray pump from the buffer tank was controlled using two liquid level sensor feedback. The water flow rate of the spray pump from the buffer tank was measured using a turbine flowmeter. According to the water flow rate, the proportion of pesticide was injected into measured using a turbine flowmeter. According to the water flow rate, the proportion of pesticide was injected into the mixer with water together. The mixture of pesticide and water was sprayed to the target. the mixer with water together. The mixture of pesticide and water was sprayed to the target.During During the spraying, water and pesticide was measured at the same time, the maximum error of the mixture ratio the spraying, water and pesticide was measured at the same time, the maximum error of the mixture ratio was 6.75%. The maximum error of mixture uniformity was 6.33%, and the variation coefficient was 7.91%. was 6.75%. The maximum error of mixture uniformity was 6.33%, and the variation coefficient was 7.91%. The The system proposed supplied the water and pesticide in proportion, and the range of the mixture ratio was 100:1 ~ system proposed supplied the water and pesticide in proportion, and the range of the mixture ratio was 100:1 ~ 1000:1, it can satisfy the requirements of spraying in paddy field. 1000:1, it can satisfy the requirements of spraying in paddy field.The The experiment was used the cochineal solution as the pesticide, the next step will be to carry out field experiments experiment was used the cochineal solution as the pesticide, the next step will be to carry out field experiments with real pesticides. with real pesticides.Design and experiment of online mixing spraying Design and experiment of online mixing spraying system systemAdress Adress：：483# 483# WushanWushanStreet, Street, TianheTianheDistrict, Guangzhou, P.R. China District, Guangzhou, P.R. ChinaWebsite Website：：http://www.nyhklm.org/http://www.nyhklm.org/Contact Contact：：LianLianHU HUTel Tel：：+86+86--2020--38676975 Fax38676975 Fax：：+86+86--2020--85280158 Email85280158 Email：：lianhu@scau.edu.cnlianhu@scau.edu.cnCollege of Engineering, South China Agricultural University College of Engineering, South China Agricultural UniversityKey Laboratory of Key Technology Key Laboratory of Key Technologyon Agricultural Machinery and Equipment, Ministry of Education on Agricultural Machinery and Equipment, Ministry of Educationonline online mixingmixingspaying system spaying system Meng Zhang, Lian Hu, Qibao Yuan, Runmao Zhao, Lingmao Tang, Hao Zhou, Tong Wu MAX MIN Water Pesticide 控制板 Controller Precision plunger pump Level switch A Level switch B Flowmeter Solenoid Buffer Tank Mixer 0 100 200 300 400 500 600 700 800 900 1000 Artificial mixture Machine mixing 1 Machine mixing 2 Machine mixing 3 Measuring point concentration/ppm Buffer tank left Middle Right The Theconcentration of the measurement points concentration of the measurement points