EQUATION OF MOTION OF THE JOHN DEERE 6095B TRACTOR AS AN AUTOMATIC DRIVING OBJECT

Abstract

The main issue that has to be solved in the formation of modern systems for automatic driving of tractors is the issue of obtaining information about the current state of the machine-tractor unit relative to a given trajectory. In terms of its quality, this information should reflect the rather stringent requirements of agricultural production for the accuracy of trajectory control. Thus, to create devices for automatic driving of tractors, it is necessary to know the characteristics and properties of these machines as objects from the point of view of the theory of automatic control. When examining such machines, first of all, it is necessary to establish which parameter should be considered as input. With manual control, the feedback is closed visually on the right front wheel, more precisely at the point of contact of the wheel with the ground. The main goal of this work is to obtain equations connecting the input and output coordinates, as well as the input coordinate and coordinates of the middle of the front and rear axles of the tractor. It is also necessary to establish under what initial data a simplified equation can be used, taking into account only the kinematics of the tractor movement and not taking into account the elasticity of tires and deformation of the soil. For this, the problem is solved both taking into account the elasticity of tires and deformation of the soil, and without taking into account these factors. Frequency characteristics are compared, obtained using a simplified equation and taking into account the above factors at different speeds. During the research, the equations of motion of the tractor were obtained taking into account the deformation of pneumatic tires and soil. This equation allows you to study the movement of the tractor in the presence of external lateral forces. Such forces can be centrifugal forces when moving along a curved trajectory and forces from trailed and mounted implements on a tractor. The equation is valid for small steering angles of the tractor idler wheels. A simplified equation is obtained that does not take into account the deformation of tires and soil. This equation can roughly describe the movement of a tractor on solid ground, which is little deformed, at relatively low speeds. It is advisable to use this equation only at speeds not exceeding 1.7 m/s on dense ground. Both equations characterize the tractor as an object of regulation and allow the selection and design of an automatic steering system.