ARS | Publication request: Development of a PWM precision spraying controller for unmanned aerial vehicles

Submitted to: Journal of Bionics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 28, 2010
Publication Date: September 1, 2010
Citation: Zhu, H., Lan, Y., Wu, W., Hoffmann, W.C., Huang, Y., Xue, X., Liang, J., Fritz, B.K. 2010. Development of a PWM precision spraying controller for unmanned aerial vehicles. Journal of Bionics. 7:276-283.

Interpretive Summary: Aerial application of pesticides is an effective means of crop protection over large regions, but new technologies are needed for precise application of pesticides in small or difficult-to-access areas. Unmanned aerial vehicles (UAV) represent a new tool for the aerial application of crop protection materials but new spray control systems must be developed. This work focused on development of an electronic spray system for a UAV that can target specific areas of pest infestation within a field. The spray system can be controlled via wireless signals, which allows the operator on the ground to vary the spray rate and power the system on and off in flight. The UAV and the electronic spray system have potential for precision crop production and crop protection, creating a new way for American farmers to treat their crops for pest and weed infestations with reduced pesticide use.

Technical Abstract: This paper presents a new pulse width modulation (PWM) controller for unmanned aerial vehicle (UAV) precision sprayer for agriculture using a TL494 fix-frequency pulse width modulator together with a data acquisition board and developed software. The PWM controller was implemented through the guidance system on the UAV with control commands sent between the helicopter and the ground control station via a wireless telemetry system. The PWM controller was tested and validated using LabVIEW 8.2. Several analyses were performed in a laboratory to test different control signals. The results obtained with the PWM controller on the UAV precision sprayer has promise as a technique to higher precision of spray applications that will improve efficiency of pesticide application, especially in crop production areas.