The Tractor-Cart System Controller with Fuzzy Logic Rules

Post-planting operations (e.g., fertilizing, cover crop planting) with a tractor and towed cart in standing crop (e.g., corn) are challenging. Tractor and cart should be kept within a certain boundary region to avoid crop damage. An automatic guidance system on the tractor is the solution of the issue; however, tractor's auto-guidance does not guarantee the cart clear and exact following of the tractor. There is insufficient research in automatic control of a towed cart. Therefore, this research was undertaken to design a controller to manage lateral and longitudinal positions of a tractor-towed cart. A novel fuzzy logic based adaptive controller algorithm is proposed to control tractor-cart system steering with additional steering torque for the cart, ensuring that the entire system follows the desired trajectory within the set constraints. A hydraulic drive design for the cart was developed with a control principle to closely follow the tractor's path and minimize damage to the plants. The proposed steering algorithm and designed controller were validated with interchangeable trajectory patterns via simulations in MATLAB/Simulink. The results demonstrated that the performances of the designed hydraulic drive and the accuracy of the proposed control algorithm were appropriate to steer the towed-cart with minimal damages on plant rows.