Optimal Path Tracking: Benchmarking an NMPC for a Wide-Span Autonomous Agricultural Machine

In this article the development of an optimal controller for a special type of tractor, commonly referred to as gantry tractor, is presented. A Model Predictive Controller (MPC) based on a single track model controls the global kinematic behavior of the tractor. The formulation of the optimal control problem aims at guaranteeing an extremely accurate path tracking. In a subsequent step, the controls for the individual four wheels are calculated following a no-slip hypothesis. A high frequency controller corrects the lateral behavior of the vehicle to ensure higher tracking accuracy. The performance of the MPC is compared to that of a geometric path tracking controller in terms of their respective tracking accuracy.