Autonomous Agricultural Robotics for Smallholder Farms: Design Theory and Field Validation in Nigeria

This study develops a design theory for autonomous agricultural robots suited to Nigerian smallholder farm conditions and validates the theory through prototype design, fabrication, and field testing. Agricultural robotics represents a frontier of precision agriculture automation that has the potential to address Nigeria's farm labour shortage and improve operational precision in planting, weeding, and harvesting. However, existing agricultural robots are designed for large, uniform farm fields typical of developed country agriculture and are entirely unsuitable for the small, irregular, terrain-variable, and diversity-cropped fields of Nigerian smallholders. This study proposes an original theoretical framework for smallholder-adapted agricultural robotics that incorporates constraints of small plot size and irregular geometry, crop diversity and variable planting patterns, low-cost manufacturing from locally available components, operator simplicity for low-technology users, and robustness to rough terrain and variable ambient conditions. Robot kinematics, sensing, and control architectures are developed within this framework. Three robot prototype systems are designed and fabricated: a seeder-fertiliser robot for cereal planting, a mechanical weeder robot for inter-row cultivation, and a UAV imaging system for crop monitoring. Field trials are conducted over two seasons at research farms at the University of Ibadan and Ahmadu Bello University, and on 15 smallholder farms in Ogun and Kano States. Performance, reliability, and farmer acceptance are assessed. Findings demonstrate that prototype robots achieve operational precision significantly better than manual operations for seeding and weeding, with 85 percent farmer acceptance in structured trials. The study contributes an original smallholder agricultural robotics design theory for Nigeria.

Keywords: agricultural robotics, autonomous systems, smallholder farms, Nigeria, precision agriculture.