An Engineering Model of a Knife Roller for Thinning Forest Crops

To carry out the thinning of forest crops, it is necessary to use mechanized means, such as knife rollers. The review of scientific literature has shown that the lack of domestic knife rollers is a significant problem in artificial reforestation. The aim of this study has been to substantiate the technological parameters of knife rollers, considering their position relative to the soil surface, as well as the level of rigidity of the safety springs. To develop the parameters of new types of tools, it is necessary to use modern software that allows taking into account all the factors affecting the design. Using computer-aided design systems, a 3-dimensional solid model of a knife roller has been created, which has become the object of study. A review of modeling methods has shown that the most widely used approaches today are those based on numerical calculations. To perform the calculations, the Universal Mechanism 9.1 complex has been used, designed for modeling dynamic and kinematic processes in mechanical systems. Using the named software package, a virtual model of a knife roller has been created, taking into account the interaction of the machine links and the friction force of the roller upon contact with the ground. A computational experiment has been conducted to establish the kinematic and dynamic characteristics of the roller at different levels of rigidity of the safety springs and a change in the height of the hitch installation relative to the soil surface. Parameters such as the trajectory of the hitch movement, the tractor traction force, and the forces arising during the interaction of the roller with the soil have been determined. Based on the developed parameters, a prototype of a knife roller has been manufactured, which has passed laboratory tests in a soil channel. In the course of experiments using strain gauge equipment, the traction forces required for the operation of the tool have been measured. The data obtained have confirmed the accuracy of the proposed simulation model and its efficiency for further design and practical application.