Improving the harvester functionality by optimizing the manipulator kinematic scheme

To minimize the negative impact of wheeled and tracked forest vehicles on soil and vegetation, it is crucial to protect natural ecosystems during activities such as wood harvesting and tree maintenance. This study focuses on one of these measures, namely, maximizing the area of the harvester’s working zone, within which it can cut down trees without additional movement, thereby preserving soil integrity. The manipulator kinematic scheme, typical for most modern harvesters, was considered, and calculated dependencies were obtained to determine the shape and basic geometric characteristics of the working zone. A mathematical model has been developed to determine the optimal values of the lengths of the manipulator links, ensuring the maximum area of the harvester’s working zone, taking into account the necessary design and operating restrictions. Model results demonstrate the effectiveness of the design phase of harvester manipulators. When designing harvesters with a load moment in the range from 150 kN·m to 300 kN·m, optimizing the combination of link lengths in the manipulator’s kinematic scheme can increase the working zone area by up to 30%. This increase is associated with the increase in the maximum radius of the working zone, which can reach from 15% to 17%. This leads to a similar increase in the width of the strip of felled trees that can be cleared with a single pass by the harvester. A greater effect of optimizing the manipulator kinematic scheme was observed when operating harvesters in logging areas with trees of smaller average diameter. Optimizing the manipulator kinematic scheme resulted more effective in logging areas with smaller diameter trees. By reducing the number of longitudinal passes in the logging area, the negative impact of mechanized logging on the forest ecosystem can be minimized.