Autonomous systems for precise spraying - Evaluation of a robotised patch sprayer

Advances in different technologies, such as global navigation satellite systems, geographic information systems, high-resolution vision systems, innovative sensors and embedded computing systems, are finding direct application in agriculture. These advances allow researchers and engineers to automate and robotise agricultural tasks no matter the inherent difficulties of the natural, semi-structured environment in which these tasks are performed. Following this current trend, this article aims to describe the development and assessment of a robotised patch spraty -20ying system that was devised for site-specific herbicide application in agricultural crops and is capable of working in groups or fleets of autonomous robots. The robotised patch sprayer consisted of an autonomous mobile robot based on a commercial agricultural vehicle chassis and a direct-injection spraying boom that was tailor-made to interact with the mobile robot. There were diverse sources (on-board and remote sensors) that can supply the weed data for the treatment. The main features of both the mobile robot and the sprayer are presented along with the controller that harmonised the behaviour of both main subsystems. Laboratory characterisation and field tests demonstrated that the system was reliable and accurate enough to accomplish the treatment over 99.5% of the detected weeds and treatment of the crop with no weed treated was insignificant; approximately 0.5% with respect to the total weed patches area, achieving a significant herbicide savings.