Designing an Unmanned Aerial Vehicle for Specific Aerial Applications of Insecticides and Herbicides

Abstract

In this study a gasoline powered hexa-copter unmanned aerial vehicle (UAV) has been designed as a solution to farmers’ need for a low cost, easy to maintain, long flight duration, and multi-purpose means of specific aerial applications for insecticides and herbicides. Application of herbicides and pesticides by airplane is an example of how farmers have used technology to improve their bottom line and overall quality of life. Fields can now be sprayed in under an hour instead of consuming an entire day. However, if a producer has noxious weeds in only a small area, fixed-wing aerial application cannot be used as it is only accurate enough to do an entire field. Currently there is no solution for small scale, accurate, aerial herbicide application to meet this need. The currently available Yamaha Rmax UAV costs a tremendous amount of money and also requires a lot of money to maintain. Though it may be useful in large scale aerial spraying on the farm land, it would not be used in targeted specific areas as it is not efficient in specific applications. The gasoline powered hexacopter UAV designed in this study is a low cost solution to farmers’ need for specific aerial applications of insecticides and herbicides. The UAV design can carry 2–3 gallons of herbicide (16.7–25.0 lbs.) for a flight time of more than 30 minutes without refueling. The design could be transported in a 60.3in × 56.7in pickup bed. Structural and fatigue analyses are performed on the complete structure using state of the art software SolidWorks Simulation. The minimum factor of safety is obtained to be 10 based on maximum von Mises stress failure criteria. Under normal conditions with an estimated commercial use of 100 cycles per day it is observed that the design would survive for about 13 years without any fatigue failure. A drop test analysis is performed to ensure the design can survive a 5 feet freefall and a frequency analysis is also performed to observe the critical natural frequency of the structure. Flow simulations are performed on the 6 propellers/blades model using state of the art software SolidWorks Flow Simulation to observe the effect of vorticity interactions on the lift force. The design has been reasonably optimized based on maximizing the lift force. With this new UAV design small scale and substantial farmers could afford a personal UAV for aerial applications with a small amount of capital whose absence hindered efficient and effective specific aerial application for many years.