Modeling the movement control of a wheeled agricultural machine in real time

The research, which purpose is the development of a motion control system for wheeled agricultural machines, is conducted in Polzunov Altai State Technical University. One of the most important steps in this case is the testing of the developed control algorithms. It is advisable to replace the field trials by real-time motion modeling, which allows to significantly reduce financial and time costs. The developed control algorithm can be conditionally divided into global and local regulation. Global regulation must determine the angle of rotation of the steered wheels (or the angle of the frame break) by a deviation from the specified trajectory, which ensures the motion along the specified trajectory. Input parameters are the specified path of motion, the current coordinates of the machine and the projection of speed on fixed axes. Local control provides the implementation of the set value of the angle of rotation of the steered wheels. To the input of the local adjustment program is given the values of the set and current angles of rotation of the wheels and the direction of rotation of the electric motor of the maneuvering device. The algorithm for determining the required angle of rotation of the wheels is based on the method of predicting the position of the wheeled vehicle through the predetermined forecast time. In real-time tests, the wheeled vehicle is replaced by its mathematical model, obtained using the differential equations of plane motion. The complex of equipment provides registration and generation of the necessary parameters for the operation of the control system in real time. The tests were carried out on the experimental stand «steering - front suspension of the vehicle». The front steerable wheels were rotated by an electromechanical maneuvering device to an angle providing movement along a given trajectory. The motion along rectilinear and curvilinear trajectories was modeled taking into account perturbations from the side of the support surface and without them. When moving along a curvilinear trajectory, the deviation from the specified trajectory does not exceed 0,3 meters at a speed of 3,33 m/s. Based on the results of the experiments, it was established that the implemented control algorithm ensures motion along a given trajectory with a sufficient degree of accuracy.

precise agriculture, motion control system, wheeled vehicle, differential equations of motion, mathematical model, real-time modeling