A Weed Control Unmanned Ground Vehicle Prototype for Precision Farming Activities: The Case of Red Rice

The implications of red rice on the total production of commercially cultivated rice are widely documented in the literature. Red rice, due to its genetic similarity with cultivated rice, is not affected by typical herbicides, and thus it is considered as a major weed challenge. Conventional and chemical-based solutions to address red rice are inefficient. In this research, a simulated and a real-world prototype robot system for weed control in paddy fields is developed, which consists of an Unmanned Ground Vehicle (UGV) that is equipped with a specially designed rod mechanism. The rod mechanism is coated with a porous absorbent material (e.g., sponge) that is saturated with herbicide and uses a sensor-based control mechanism for applying the herbicide only to the top of red rice plants thus avoiding the contact with the commercially cultivated rice plants. The rod dynamically reacts to the harsh terrain, via using a slope and a height control automation system, in order to retain the rod mechanism’s height at a certain level and horizontally aligned to the terrain so as to affect only the red rice plants. The method can be applied after the end of the growing season as red rice plants exceed in height the plants of the commercial rice. To that end, the impact of red rice on the cultivation of commercial rice varieties can be limited thus ensuring supply stability downstream the agri-food value network. The prototype robot system operates in a fast and accurate manner and delivers consistent results regardless of the geomorphology of the terrain.