Design Considerations for a Remote-Controlled Four-Wheel Pesticide Spraying Machine for Soybean: A Review

Abstract—Pesticide spraying in Indian field crops is still performed largely with manually operated knapsack sprayers, which expose farmers to toxic chemicals, cause fatigue and muscular strain, and give uneven application. Battery-operated and remotely controlled ground sprayers have been proposed to overcome these problems, but the published designs differ widely in drive, control and spraying arrangements and are rarely evaluated in the field. This paper reviews the literature on battery-operated sprayers, remote-controlled wheeled sprayers, spray application and vehicle steering, compares the reported systems, and identifies the research gaps. The reviewed machines converge on four-wheel drive with 12 V geared DC motors, a centrally mounted tank, a 12 V DC pump and a microcontroller-based motor driver, but they share recurring limitations: small wheels and low ground clearance, one or two nozzles, skid turning, unregulated flow as the battery discharges, and an absence of field performance data. Based on these findings, we propose a high-clearance remote-controlled four-wheel sprayer for soybean with 1067 mm chain-driven wheels, Ackermann front steering, a track adjustable from 1200 to 1500 mm, a 2000 mm boom with five hollow-cone nozzles at 450 mm row pitch, a 25 L tank, and an ESP32 controller operated from 50–100 m. Design calculations indicate an effective field capacity of about 0.31 ha/h, reducing spraying time from 3–4.5 h to about 1–1.5 h per acre. A compact prototype model with hub-drive wheels, a 16 L tank and a four-nozzle boom is also described and analysed. Keywords—Remote-controlled sprayer; battery-operated sprayer; four-wheel drive; pesticide application; soybean; boom sprayer.