Analysis a cutting edge geometry influence on circular saw teeth at the process of crosscutting wood

Nowadays, the wood cutting process looks like a technological scheme consisting of several connected and relatively inseparable parts. The crosscutting wood is the most widespread in the process of fo­rest exploitation; it is used at tree exploitation, shortening stems and assortment production. The article deals with the influence of the cutting edge geometry of circular saws on the torque and also on the cutting performance at the crosscutting wood therefore there is the influence on the whole cutting process. In the article there is described detailed measurement procedure, used measuring devices and the process of results analysis. Knowledge of wood crosscutting process and choice of suitable cutting conditions and cutting tools will contribute to decrease production costs and energy saving

Torques from manual tools for directional tree felling

Motor-manual tree felling is commonly practiced in many regions of the world. Trees falling in unwanted directions cause severe accidents and extra work in motor-manual logging. Different kinds of manual tools can help force trees to fall in the desired direction, but their capacity are uncertain due to a lack of suitable evaluation methods. Reliable recommendations of felling tools’ limits could help reduce human injuries and damage to property. The objective of this study was, therefore, to develop and evaluate a realistic and convenient method for studying felling tools’ capacity in terms of the potential torque they can generate. A theoretical model of torque components was constructed and the mechanics of the falling tree and of the studied equipment were explained. The developed method uses real trees, which were cut at 1.65 m above stump height to create trial stems. Trial stems were anchored to a neighboring tree and then cut as if they were to be felled. Standardized forces were applied to a forestry jack, felling lever, and wedge, and their effects on the trial stem were recorded by a load cell in the anchoring line. The method proved suitable for the evaluation of forestry jacks, while it needs improvements to evaluate felling levers and wedges thoroughly. Methodological improvements are suggested and practical applications are discussed and demonstrated in terms of the forestry jack’s capacity to deal with trees with unfavorable angles of inclination

A deterministic LQ tracking problem: parametrisation of the controller

summary:The article discusses an optimal Linear Quadratic (LQ) deterministic control problem when the Youla–Kučera parametrisation of controller is used. We provide a computational procedure for computing a deterministic optimal single-input single-output (SISO) controller from any stabilising controller. This approach allows us to calculate a new optimal LQ deterministic controller from a previous one when the plant has changed. The design based on the Youla –Kučera parametrisation approach is compared to the classical LQ design