Modeling and simulating the harvester header dynamics using 3-way valve and PID controller

Abstract

This study presents the modeling and simulation of an automatic header height control system for combine and sugarcane harvesters, based on a simplified electrohydraulic configuration using a three-way proportional valve and a single-acting actuator. A proportional-integral-derivative (PID) controller was employed to adjust the valve spool position according to the error between a reference and the measured contact force. The system dynamics were described by nonlinear differential equations and numerically solved using the Runge-Kutta method implemented in a simulation environment. The simulations were conducted under realistic field conditions, combining three supply pressures (6.8, 13.7, and 20.6 MPa), three forward speeds (1.0, 1.5, and 2.0 m s⁻¹), and three platform ballast masses (40, 60, and 80 kg). The results demonstrated that the PID controller maintained stable behavior and accurate force tracking in most scenarios. However, a performance threshold was identified: under the most demanding condition (2.0 m s⁻¹, 6.8 MPa, and 80 kg), the mean relative error exceeded 40 %, indicating a limitation in control capacity. The proposed system proved to be a low-cost and effective alternative to traditional four-way valve architectures, providing satisfactory performance in typical operating conditions. These findings support the practical adoption of simplified control strategies in agricultural machinery and provide a validated simulation framework for pre-deployment testing and parameter optimization.