Development of Unmanned Aerial Vehicle-Mounted Sprayer for Spraying Pesticides and Fertilizer

Abstract

This study presents the design, fabrication, and performance evaluation of a hexacopter unmanned aerial vehicle (UAV) developed for precision agricultural applications, specifically pesticide and fertilizer spraying. The UAV integrates a lightweight Aluminium frame, six brushless DC motors, a custom sprayer mechanism with dual nozzles, a 5V submersible pump, and a flight control system supported by the APM 2.8 controller. Design processes involved 3D modeling with SketchUp and structural analyses using SolidWorks to assess motion and static stress responses on critical components such as motor arms and tank mounts. MATLAB was employed to model system dynamics, confirming system stability with a critically damped step response and adequate phase margins. The fabricated UAV was equipped with a 5-liter fluid tank, 336,000 mAh battery configuration, and LoRa-based wireless communication for ground control. Test results showed a battery endurance of 16.3 minutes and a total thrust capacity of 2600 grams per motor, achieving a total power requirement of 266.4 W. Although initial flight trials faced mechanical and calibration challenges, the final integrated UAV system successfully demonstrated aerial spraying capability, providing a low-cost and efficient solution for targeted agrochemical application in precision farming.