Logging Machines Research Articles

Mathematical Modeling of Forwarder Operation When Collecting Logs in the Forest Swath

Optimization of the machines allows you to increase their productivity and reduce the labor costs for performing individual elements of the technological cycle of their work in the forest. In this regard, the authors offer theoretical studies that take into account the peculiarities of the work of one of the most popular logging machines today, namely, a machine for collecting and forwarding logs (forwarder). The article discusses the technological features of the functioning of these machines, identifies ways to reduce the cost of collecting logs, justifies the rational width of apiaries, which allows collecting logs with a minimum number of movements between work positions. The main purpose of the study is to substantiate the mathematical dependence for determining the rational values of such interrelated parameters of the forwarder's operation as the distance between the working positions of collecting logs and the width of apiaries. The authors propose an analytical approach to solving the problem. On the basis of the standard technological scheme of the harvester's movement through the swath, geometric regularities of the trajectory of the manipulator movement, dimensional characteristics and location of the prepared logs are revealed. As a result of the work, mathematical dependencies are constructed that make it possible to determine the rational values of the desired parameters. The results can be used by research organizations in planning the production process of logging operations. The introduction of author's recommendations into production will contribute to improving the efficiency and operation of forestry equipment.

Динамическая модель харвестера, оснащенного канатной анкерной системой, при проведении лесозаготовительных работ на крутом склоне

The efficiency of using logging machines for work in mountainous or hilly areas characterized by the presence of steep slopes depends on many factors, among which the quantitative parameters of the dynamic state of both the harvester itself and the anchor system play a priority role to ensure the safe operation of these technological machines. This article considers a complex spatial dynamic model that combines into a common interconnected system all the main components of the simulated phenomenon, including directly a harvester with a hydraulic manipulator mounted on it, a movable assortment in space, an anchor system consist-ing of an anchor rope and a winch, an anchor tree for attaching an anchor rope and the soil of the support surface. The dynamic mathematical model of such a six-component system includes 35 generalized coordinates that determine the linear and angular displacements of the mass centers of the listed system components. A system of 35 differential equations constructed using the Lagrange’s equation was solved by the 4-th-order Runge-Kutta method. For this purpose, a computer program has been developed, the description of which is contained in the article. In relation to the basic version of the simulated system with quantitative initial characteristics focused on the characteristics of a three-axle wheeled harvester with a 6K6 wheel formula, calculations of oscillatory processes for dynamic parameters determining the loading of the anchor system and the safety of harvester operation in the process of assortment manipulation were carried out.

Влияние конструктивных характеристик манипулятора харвестера на оптимальные размеры рабочей зоны

The efficiency of using logging machines on a steep slope depends on many factors, including the working area of the manipulator, which can be implemented in various technological modes of operation. The geometric parameters of the implemented working area are determined by the working position of the machine in the appropriate technological mode, that is, the place of installation of the machine relative to the tree or group of trees to be harvested. Optimization of the manipulator’s working area, formed during the operation of a logging machine, is one of the most effective ways to increase its productivity. In this article, based on a previously developed mathematical model for optimizing the structural dimensions of the links of a four-link articulated hydraulic manipulator designed for spatial manipulation of the harvester head when cutting and stacking trees for further transportation to the loading area, an analysis of the influence of the main geometric and power characteristics of the harvester on the optimal size of the working area is performed.

Analysis of hydraulic drive circuit selection for a carrot collecting system

Compared to conventional mechanical transmissions, hydraulic transmission has the disadvantage of lower energy efficiency. However, it is widely employed in various working machines such as construction machines, off-road vehicles, forest logging machines, and especially agricultural machinery, owing to its flexibility in design, geometric arrangement, and simplicity in operation. In the development project for carrot harvesting machinery conjugate, hydraulic transmission is the optimal solution for the design and implementation of the carrot collecting roller system. This project is oriented towards achieving a practical result where the system structure is simple and effective, utilising hydraulic components available on the market in Vietnam. Given the myriad of hydraulic transmission circuits available, this paper undertakes an analysis based on numerical simulations of the functionality and energy efficiency of potential system design options and proposes a new practical speed control circuit. This suggested circuit uses a pressure-compensated flow control valve arranged parallel to the hydraulic motor. The study is carried out in the Matlab/Simulink simulation environment, where the circuit models are constructed using hydraulic components with practical parameter settings sourced from component suppliers. The analysis results indicate that the proposed circuit strikes a balance between functionality and economic efficiency.

Statistical analysis of forest machines ergonomic parameters

The main technology currently used in wood harvesting in Russia is the cut-to-length technology (CTL) based on the use of two machine types: harvesters and forwarders. Powerful and manoeuvrable hydraulic manipulators (cranes) are a main part of the equipment of both the harvester and the forwarder. A statistical analysis of ergonomic parameters of the manipulator control system equipped with partial automation option is described in this article. Two machines were studied in natural field conditions. Differences in the frequency and duration of telescopic extension boom control activations were identified. The distributions of the extension boom use parameters for the crane of the logging machines were defined. It can be used to build various models for the analysis of promising crane design solutions. It is determined that the duration of the rocker switch single press has a log-normal distribution and the period between switch activations has an exponential distribution.

Incorporating Simulators into a Training Curriculum for Forestry Equipment Operators

Forestry equipment simulators offer opportunities for new operators to become familiar with operating logging machines as well as a promising solution to the high costs of training forestry equipment operators. Current literature lacks a synthesis on how best to train forestry equipment operators using simulators. The goal of this review was to identify effective ways to incorporate forestry equipment simulators into an equipment operator training curriculum. We analyzed a total of 14 independent studies in which construction and forestry equipment operators were trained on simulators and engaged in discussions with nine professionals in the field of heavy equipment operator training. In this review, traditional machine training and simulator training practices are introduced. Then, four key aspects of skill acquisition for forestry equipment operators are identified. Information collected from peer-reviewed literature and discussions with industry experts are used to consider how each aspect of skill acquisition is addressed in both traditional training using real machines and simulator-based training. Drawing on these sources, benefits and drawbacks of traditional machine training and simulator-based training for forestry equipment operators are synthesized and discussed. Finally, a model for an integrated and adaptive training curriculum that incorporates principles and technologies from both traditional machine training and simulator training is presented.

Basic rules of safe operation of universal logging machines

For small and low-volume logging enterprises that predominate in the forest complex of the Russian Federation, in conditions of an acute shortage of forest fellers, universal logging machines are one of the most preferred options for carrying out logging operations. Compared with classic multi-machine logging complexes, they require significantly less capital, operators, and the cost of moving them from cutting area to cutting area. The article considers modern variants of universal logging machines — harvesters, forwarders, and felling — skidding-processing machines, and the rules for their safe operation.

Совершенствование конструкции цепных пильных аппаратов

At the present time cutting of trees, delimbing, and crosscutting with gasoline-powered saws and logging machines are carried out in the forestry cutting area operations with the help of chain saws. Therefore, the efficiency of forestry work depends on the reliability and performance of the chain saw machine. The problem of increasing the reliability of sawing machines, increasing their service life becomes particularly relevant due to a sharp decrease in the volume of logging with the use of multi-operator logging machines. In this regard, the wide use of efficient motor tools, improvement of their design, especially the chain saw machine, with regard to reducing the harmful effect on the operator is of great importance. Poor quality and performance of domestic machinery has led to the fact that mainly imported tools are used in Russia, while their price and maintenance costs are constantly increasing and, consequently, the cost of harvested wood increases too. In this regard, it is important to develop and introduce new, more perfect tool designs that are not only as good as the reliability and performance of the imported equipment, but even much better. Taking it into account, we can consider that the issue of chain saw research with regard to the specifics of its design, as well as its science-based improvement will increase the operational performance and reliability of machines, which is important for the logging industry. One of the main causes of saw unit failures is the increased wear of its components accompanied by the improper saw chain tensioning. Currently, the proposed devices for regulating the tension of the saw chain require periodic stopping of the saw, as none of the devices provides its automatic tensioning. Thus, the purpose of the research is to improve the reliability and service life of chain saws of forestry machinery on the basis of improving the design that provides automatic tensioning of the saw chain. The paper describes the design solutions to improve the saw machine, that is the design of the device that provides automatic tensioning of the saw chain when the saw bar is fixed, allowing to increase the reliability and service life of chain saws, to reduce the chain slipping during the work, which will increase the safety of work and reduce the risk of injury to the operator.

REPAIR AND RESTORATION OF CRITICAL PARTS OF LOGGING MACHINES WITH ELECTROMECHANICAL PROCESSING

REPAIR AND RESTORATION OF CRITICAL PARTS OF LOGGING MACHINES WITH ELECTROMECHANICAL PROCESSING

Investigation of geometric characteristics of the micro landform of the cutting area as a source of perturbing oscillations of logging machines

The article presents the results of experimental studies of the micro landform of the cutting area surface as a source of perturbing continuous oscillations of the sprung and unsprung masses of the logging machine. The substantiation of the expediency of studying the microprofile of forest support surfaces in the framework of this work is presented. The characteristic of the objects of the experimental study of the micro landform is given. A new measuring complex and the procedure for measuring geometric parameters of irregularities and slopes of the forest support surface of vehicles were proposed. The justification of the number of measurements in the planning of the experiment is given. As a result of data processing after approximation, normalized correlation functions and their approximation coefficients for the studied types of forest growing conditions were obtained. The obtained curves of normalized correlation functions have a decreasing character, which indicates the presence of a strong correlation on a small section of the length and differ in the steepness of the decline and the distance of the correlation, which varies from 1.8 to 11.6 m for different sections. The obtained approximation coefficients quantitatively characterize the perturbing effect of the irregularities of the natural surfaces of cutting areas of various types of forest growing conditions on the movement of logging machines.

Подходы к имитационному моделированию рабочих процессов канатной лесозаготовительной машины для работы на склонах

Currently, due to a decrease in the volume of possible timber extraction in relatively convenient areas characterized by favorable natural relief, the development of logging technologies and appropriate logging equipment for work on steep slopes becomes an urgent technical and economic task. This paper discusses approaches to simulation modeling of work processes occurring in structural elements and systems of rope logging machines during their operation on steep slopes. The developed approaches can be used in the development of digital twins of logging equipment.

Impacts of Logging-Associated Compaction on Forest Soils: A Meta-Analysis

Soil compaction associated with mechanized wood harvesting can long-lastingly disturb forest soils, ecosystem function, and productivity. Sustainable forest management requires precise and deep knowledge of logging operation impacts on forest soils, which can be attained by meta-analysis studies covering representative forest datasets. We performed a meta-analysis on the impact of logging-associated compaction on forest soils microbial biomass carbon (MBC), bulk density, total porosity, and saturated hydraulic conductivity (Ksat) affected by two management factors (machine weight and passage frequency), two soil factors (texture and depth), and the time passed since the compaction event. Compaction significantly decreased soil MBC by −29.5% only in subsoils (>30 cm). Overall, compaction increased soil bulk density by 8.9% and reduced total porosity and Ksat by −10.1 and −40.2%, respectively. The most striking finding of this meta-analysis is that the greatest disturbance to soil bulk density, total porosity, and Ksat occurs after very frequent (>20) machine passages. This contradicts the existing claims that most damage to forest soils happens after a few machine passages. Furthermore, the analyzed physical variables did not recover to the normal level within a period of 3–6 years. Thus, altering these physical properties can disturb forest ecosystem function and productivity, because they play important roles in water and air supply as well as in biogeochemical cycling in forest ecosystems. To minimize the impact, we recommend the selection of suitable logging machines and decreasing the frequency of machine passages as well as logging out of rainy seasons especially in clayey soils. It is also very important to minimize total skid trail coverage for sustainable forest management.

Marketing analysis of the technological equipment market for the Russian logging industry

The results of the analysis of the equipment market for the logging industry in Russia are presented. A literary review of the domestic and foreign equipment markets is presented, the size of the market is estimated, its segmentation is carried out, consumer preferences are identified and characterized. The assessment of the key product range for the industry is carried out, the main foreign competitors are identified and the existing barriers to the entry of domestic products into the market are analysed, as well as ways to overcome them are proposed and justified. The features of the demand for products are analysed, the possibilities of import substitution of currently used logging machines are studied and the ways of their marketing promotion are presented. The directions of further development of forest engineering and the entire forest complex of Russia based on import substitution and ensuring the economic and technological security of Russia are substantiated.

Technical Solutions of Forest Machine Hybridization

The paper deals with the characteristics of three different types of power train hybridization of forest logging machines and with the benefits of reducing environmental impacts by comparing new technology with more conventional, older technology. New hybridization options that could be implemented in forestry machines are also discussed. The paper divides a hybrid solution into three classes based on the energy used in the system of hybridization. First is an electro-hybrid system that uses an electric motor and battery or different storage device. The second, a hydraulic hybrid system, is a solution with a hydraulic accumulator, hydraulic motor, and pump. The third system is a combination of the electro-hybrid and hydraulic-hybrid system. The current technical and technological development of hybrid drive systems, as well as their components, has led to significant improvements in drive performance and thus better performance of the new generation of forest vehicles. Improved energy efficiency using hybrid propulsion systems in forest vehicles would result in a significant reduction in greenhouse gas emissions and possibly lower maintenance costs.

Особенности российского рынка лесозаготовительной техники

Russian forest sector forms an attractive market for harvesting and logging equipment, however the position of Russian manufacturers is extremely weak. A brief overview of the current state of the market is presented with reference to the open sources. Its features are mentioned as compared to the road construction and agricultural machinery sectors. Three transnational companies dominate the Russian market of harvesting and logging equipment: John Deere, Ponsse and Komatsu. Most of the purchased equipment falls on machines for cut-tolength technology, such as harvester and forwarder. The market volume of new machines is estimated at 330–420 forwarders, 165–300 harvesters, about 30–40 feller bunchers and the same number of skidders. There were two waves in the consolidation of the position of foreign companies in Russia. The first was connected with the delivery of equipment and the development of foreign brands in Russia against the background of still high-profile positions of Russian manufacturers in the market. The second is the takeover of enterprises having a service network and reputation by diversified transnational corporations. The main strategies of the leading companies in the current situation are the export of equipment to Russia and the development of a service network. Companies do not turn to another level associated with the opening of production sites or joint ventures for the production of harvesting and logging machines. The Russian market is characterized by the absence of a strong Russian manufacturer of harvesting and logging machines, which is ready to significantly influence or actively participate in the processes of import substitution. The position of such a manufacturer is gradually occupied by the Belarusian Amkodor Holding. The purchase of new harvesting and logging machines can afford major timber companies. The main production sites of harvesting and logging machines are located in Finland, Sweden, USA, and Canada. In order to support forestry machine engineering, in addition to economic measures of stimulation approved in other sectors, it is proposed: to organize the work of scientific forest engineering centers on the base of public-private partnership with the financial support from the major vertically-integrated timber corporate groups; to stimulate the development of Russian sector-specific information technologies for harvesting and logging; to initiate the partnership with companies from the People’s Republic of China to launch the design and production of new-generation harvesting and logging machines.

Математическая модель расхода топлива форвардера «амкодор-2682» при выполнении лесохозяйственных работ

Cost justification of fuel and lubricants is high on the agenda of planning and practical use of forwarders in Russia and abroad. The problem solution is becoming increasingly important due to rising prices for fuel and energy resources. The share of costs for fuel resources ranges from 46 to 70 % in different natural and industrial conditions. This is due to the presence of cutting areas with different characteristics of the species composition. Currently, there are consumption rates for fuel and lubricants for mechanized work performed in forestry. However, they lack regulatory guidelines for calculating the fuel of modern logging machines used in skidding. There are basic standards for consumption of fuel, oil, and lubricants for different brands of domestic and foreign cars, trucks, and buses, but they also have no information on forestry equipment. The research purpose was to show the fuel consumption for the forwarder Amkodor-2682 when harvesting assortments in the climatic conditions of the Mari El Republic. The purpose was achieved through experiment using the volumetric method of refilling the machine fuel tank at the end of the operation cycle. The studies were provided with fixing the diameters and volumes of the felled trees. The forwarder fuel tank was filled to the top of the tank filler. Processing of the swath site was carried out with skidding of one pack of logs. The machine was stopped and the fuel tank was filled in after each operation of logging (idling, bundle assembling, hauling, bundle unloading). The amount of fuel in the tank was accurately fixed each time. Processing the data allowed us to obtain a regression model. This model characterizes the average fuel consumption for the forwarder Amkodor-2682 at different diameters of felled trees. Using the obtained results in forestry will make it easier to plan and calculate the operating costs of skidding equipment.

Topological optimization by designing structural elements of logging machine manipulators

The structures of manipulators of modern logging machines are subject to a wide variety of requirements related to the implementation of the functions of these machines, as well as the technology of manufacturing, operation and disposal of structures. The leading requirements are to ensure high strength and operational reliability under a wide range of loads, high and low temperatures. In this case, it is necessary to obtain the minimum metal consumption of the design product. Structural optimization, in particular, topological optimization, should be used when 9designing manipulators for logging machines. The use of topological optimization makes it possible by calculation to carry out the redistribution of material in the calculation area of the design product, taking into account the required conditions. The use of Altair Inspire 2018.3 software tools makes it possible to reduce the weight of the designed structural element of the hydraulic manipulator of the forestry machine by 39%. At the same time, acceptable indicators of tensile strength, deformation, and standard safety factors are provided.

Variability of forwarder truckload parameters in the Pryazha forestry division of the Republic of Karelia (Russia): A computer experiment

Abstract The goal of the present research is to analyze parameters of a bundle of logs for various models of forwarders in the Pryazha division of forestry of the Republic of Karelia. The investigated parameters were mass and volume of a bundle of logs, stacking factor of the bundle and the number of wood assortments in the bundle. The following models of forwarders have been investigated: John Deere 1210E, John Deere 1110E, Ponsse Elk, Ponsse Wisent, Amkodor 2661-01, Rottne F13D, Rottne F15D, Rottne F18D. We estimated the parameters of bundles formed from spruce sawlog 6.1 m long and bundles formed from spruce pulpwood 4 m long. Data on stem forms from harvester recorders have been collected to assess the parameters of a bundle of logs. Parameters of bundles have been determined based on computer experiment. The experiment consists of the following steps: random selection of the stem from the database; simulation of the cut-to-length process; simulation of log stacking process; calculation of parameters of a bundle of logs. We found that parameters of bundles vary to a quite substantial extent. Average variability of a bundle of logs formed of 6.1 m long spruce sawlog is 4.5 t, variability of the volume is 5.8 m3, and variability of the number of wood assortments in a bundle is 49 pcs. For a bundle made up of 4 m long spruce pulpwood variability of mass is on average 2.8 t, that of volume – 2.09 m3, that of the number of wood assortments – 57 pc. The presented results can inform transportation of wood on cutting areas, planning timber harvesting, as well as development new logging machines.

Повышение износостойкости сучкорезных ножей многооперационных лесозаготовительных машин

Delimbing of harvested wood is the first step towards obtaining finished products, where it is necessary to strain after achievement of maximum efficiency in the use of raw materials and quality improvement of the obtained assortment. Herewith, high-quality cleaning and minimization of damage of tree trunks is associated to a great extent with reliable operation of the delimbing and pull-through devices of logging machines that carry out both removal of branches and technological movement of wood. An intensive blunting of delimbing knives occurs in operation of the delimbing and pull-through device. As a result, the forces spent on delimbing increase and the process of stable cutting is disrupted. Partial cutting, and with an increase in pressure on the knives their cutting into a trunk and breaking out of limb occur, which reduce the quality of the harvested wood and lead to further intensification of wearing out of the cutting devices. The wearing out of knives is due to the action of a complex set of mechanical, chemical, temperature and other factors that accompany the technological process. This leads to a change in the dimensions of knife cutting edges. In order to improve the quality of delimbing and at that reduce the energy consumption, it is necessary to assess the influence of geometric and physico-chemical parameters of the cutting knives on their wear resistance, which will allow to theoretically justify the rational geometry of the cutting wedge and requirements for the physico-chemical characteristics of the recommended materials. The force interaction analysis of the cutting wedge with the cut limb has shown that, already at the beginning of the contact, the cutting blade is acted by the shock bending load, which, when peak values are reached, often leads to wearing out by chipping of sufficiently large microvolumes of the cutting edge. In this case, the wearing out of delimbing knives occurs mainly due to thedevelopment of microcracks, which are formed as a result of anti-plane deformation when applying stresses, and depends on the parameters of brittle crushing of materials. Moreover, the wearing out becomes more intense with contact with contaminated and wet, and in winter period frozen wood, which leads to intensification of corrosion and mechanical processes in the marginal areas of knife blades. The solution of the problem of increasing the wear resistance of delimbing knives can be provided by optimization of dimensions of knife wedge and formation of favorable physical and mechanical characteristics in the surface layer that minimize the wear intensity. The favorable dimensions of knife wedge were experimentally determined for this purpose. Complex alloyed chromium-nickel steel and rational modes of its heat treatment are proposed for the manufacture of delimbing knifes. Electrodeposition hardening is recommended as the surface treatment, which allows to optimize the surface roughness and form a favorable compressive stress in the marginal areas, thus providing high wear resistance of delimbing knives.For citation: Pilyushina G.A., Pamfilov E.A., Sheveleva E.V. Wear Resistance Improvement of Delimbing Knives of Multifunctional Logging Machines. Lesnoy Zhurnal [Russian Forestry Journal], 2019, no. 6, pp. 174–184. DOI: 10.17238/issn0536-1036.2019.6.174

Influence of forest growth conditions on the density of wood in the Amur region

Abstract In the system of logging machines, a factor such as the density of wood affects all components of the system. However this dependence can be more noticeable in the performance of wood felling, where logging machines have approximately the same saw body, such as a chain saw. In this regard, the problem of determining the dependence of the chainsaw on the density of wood, substantiation of effective options for the number of chainsaws in the assortment and whiplash method of logging is quite relevant. In the Far East of Russia, in particular, in the Amur region, the forest growth conditions are different from the western ones and therefore the properties of the woof differ from the generally accepted ones. The article describes forest growth conditions that influence the properties of the wood in areas of the Amur region. Using the method of density determination, the density of larch, pine and birch were studied first time in the areas of the region. The dependence of the density on humidity, age, species, season of the year and the area of growth was found out. The research results showed that in the Amur region at a humidity of 70% the density of larch varies from 745 to 1 089 kg m−3, pine from 435 to 1 081 kg m−3, birch from 403 to 878 kg m−3.