Modelling, Control and Simulation of an Unmanned Ground Vehicle for Agriculture 4.0

This thesis complies the designing of an algorithm of automatic guidance for a four wheel steering (4WS) unmanned ground vehicle (UGV) within the framework of agriculture 4.0. The 4WS is obtained by implementing two Ackermann steering mechanisms (ASM) on both front and rear axes: such mechanism generates wheels' slippage whenever both axles are steered.\\ The main purpose of the thesis is to design a controller able to pursue the automatic guidance on a given path and in the meantime optimize the velocities of each wheel in order to minimize the slippage produced by the ASM.\\ On the other hand, a simulation environment has been designed to study behaviour of the vehicle. Such environment is divided into three different parts: the UGV model that includes both kinematic (how it moves in a two dimensional space) and dynamics (how its motors behave when receiving some inputs); the navigation system that stores informations about the path to be followed, and sends the informations the controller requires to work; a controller, based on the information received from the navigation system, that computes the required steering angles of the axes to comply automatic guidance and the optimized velocity of each wheel to minimize their slippage. Many tests of the UGV performing different tasks of field-like environments have been taken to find the best configuration of the controller; the results of the simulation show that the vehicle is able to track the path correctly and to assign the best velocity to each wheel to minimize the error generated by ASM.