Perception and localization techniques for navigation in agricultural environment and experimental results

Notoriously, the agricultural work environment is very hard, where the operator manually carry out any job, often in extreme weather conditions or anyway heat, cold and rain, or simply where the working hours last from dawn to sunset. Recently, the application of automation in agriculture is leading to the development of increasingly autonomous robots, able to take care of different tasks and avoid obstacles, to collaborate and interact with human operators and collect data from the surrounding environment. The latter can then be shared with the user, informing him about the soil moisture rather than the critical health conditions of a single plant. Thus borns the concept of precision agriculture, in which the robot performs its tasks according to the environment conditions it detects, distributing fertilizers or water only where necessary and optimizing treatments and its energy resources. The proposed thesis project consists in the development of a tractor prototype able to automatically act in agricultural semi-structured environment, like orchards organized in rows, and navigating autonomously by means of a laser scanner. In particular, the work is divided into three steps. The first consists in design and construction of a tracked robot, which has been completely realized in the laboratory, from mechanical, electric and electronic subsystems up to the software structure. The second is the development of a navigation and control system, which makes a generic robot able to move autonomously in the orchard using a laser scanner as main sensor. To achieve this goal, a localization algorithm based on rows estimation has been developed. Moreover, a control law has been designed, which regulates the kinematics of the robot. Once the navigation algorithm has been defined, it is necessary to validate it. Indeed, third point consists of experimental tests, with the aim of testing both robot and developed navigation algorithm.