Vol 21, No 4 (2024)
Articles
The results of a computational experiment to determine the optimal parameters and performance indicators of a wheeled-caterpillar mover of a forest machine
Abstract
In Russia low-volume logging is performed with machines based on wheeled agricultural tractors of small and medium traction. These tractors have low cost of purchase and operation and are reliable and versatile because they can be used for not only logging and forestry work, but also for community services and agricultural work thus ensuring their year-round efficient operation. However, such tractors feature insufficient tractive force when working in difficult conditions: on deep snow, weak soils or on the rise. In this regard, a rather simple method of converting a wheeled tractor to a semi-crawler unit has been developed and successfully used in agricultural production. This provides a significant increase in their cross-country ability in difficult operating conditions, increased traction, and significant fuel savings. This article presents the results of a computational experiment based on a previously developed and researched mathematical model for substantiating the optimal parameters of a wheeled and caterpillar mover of a forest machine. The purpose of the experiment was to determine and evaluate the depth of the formed track, traction properties of the mover and the required power for given soil properties and varying loads from the wheeled and tracked mover.
Resources and Technology. 2024;21(4):1-43
1-43
Method and process model for pre-processing data from automated systems for monitoring the technical condition of combine harvesters
Abstract
Modern self-propelled agricultural machines are characterized by their technological sophistication, complexity and high cost. Ensuring reliability and serviceability of such machines is the key task of technical service. The development of technical service technologies allows collecting, processing and forecasting the technical condition of machines based on the data obtained in the process of machine operation. Data collection is performed by built-in control systems to diagnose and detect malfunctions in the work of machine units and assemblies. The aim of the research was to develop and approbate the method of preliminary data processing obtained with the automatic system of technical condition monitoring and sensors installed on combine harvesters ACROS and to formalize the developed algorithm for further automation of data preparation process for technical analysis. Data quality was assessed according to the following criteria: data volume, data types, number of attributes, presence and number of omissions, presence of duplicates, presence of anomalies, matching categories, normalization and consistency of values, possible homogeneity, and segmentation. The tools used were Python, R, Pandas, NumPy, Matplotlib libraries. The authors established that raw data from analytical systems of technical condition control of combine harvesters were not suitable for analyzing and predicting the technical condition of units and assemblies due to many missing values. The process model construction based on the developed method of data pre-processing may be considered as a concept of an information system, which allows automating the data preparation process of technical condition control systems of combine harvesters for machine processing. The presented method allowed the authors to obtain structured and informative data and correct filling of omissions and to eliminate outliers and errors. The proposed process model provides transparency, control and optimization of data handling processes, will allow excluding errors and contradictions in their further analysis, and will provide repeatability of actions in the future while processing similar datasets received from the systems of technical condition control of combine harvesters.
Resources and Technology. 2024;21(4):44-65
44-65
Substantiation of the need to study the impact of felling-skidding-processing machines on the soils of cutting areas on the slopes
Abstract
In modern economic and political conditions the felling-skidding-processing machines of the Austrian family company Konrad Forsttechnik GmbH are becoming one of the few available options for Russian logging companies to use high-quality wheeled logging machines structurally adapted for logging forest plantations on slopes. Currently, production tests of the operational efficiency of such machines are being conducted in the Irkutsk region, but, unfortunately, no attention is paid to the environmental efficiency of their operation. The article substantiates the need for a theoretical and experimental study of the negative impact of wheeled felling-skidding-processing machines on the soils of logging sites on slopes. The study should be based on an analysis of the development of logging machine designs, technological options for their use, and an analysis of modern scientific research in this field. Based on the review and analysis of scientific literature, data from the National Association of Timber Manufacturers «Russian Forest», and the Association of manufacturers of machinery and equipment of the Lestech forest complex, it is shown that the felling-skidding-processing machines of the Austrian family company Konrad Forsttechnik GmbH have very good prospects for wide distribution in various natural production conditions of logging enterprises in Russia, mainly in rough terrain conditions.
Resources and Technology. 2024;21(4):66-120
66-120
Planning timber delivery to consumers according to the transport and technological scheme of raft (section lines) — raft
Abstract
The practical implementation of a transport and technological scheme operating on the raft section lines — raft principle on the basis of an improved flat — flow unit requires planning the delivery of timber to consumers. For high-quality planning of timber rafting, it becomes necessary to justify the overall dimensions of a flat raft unit and rafts for various purposes, the design of which is based on this raft unit. A method to calculate the overall dimensions of a flat raft unit, a raft (section lines) for the initial wood floating and a raft for the main wood floating is proposed. When justifying the dimensions of this raft unit and rafts for various purposes, their actual length, width, height, initial draft and volume of wood content are calculated. Based on the proposed methodology, planning timber delivery to consumers was performed taking into account time-optimal span of the initial timber raft floating during one navigation and the rational arrangement of towboats. Provided the volume of the raft (section line) is 171.26 m3 with the annual wood turnover in the onshore warehouse of 9.0 thousand m3 and the time-optimal span of the initial raft of timber floating of 160 days, then one towboat is used with the turnover time of three days. If the annual wood turnover in the onshore warehouse is 20.0 thousand m3 and the time-optimal span for the initial timber raft floating is 120 days, then two towboats with a turnover period of two days are used, provided that the volume of the raft (section line) is 171.26 m3. In the event that the annual turnover of wood in the onshore warehouse is 30.0 thousand m3, and the time-optimal span for the initial timber raft floating is 180 days, then three towboats with a turnover period of three days should be used if the volume of the raft (section line) is 171.26 m3. On the main raft timber floating with an average volume of wood in a raft of 3425.27 m3, it is necessary to use one towboat and, depending on the transport conditions, auxiliary towboats or special raft control tools.
Resources and Technology. 2024;21(4):121-149
121-149
Hydrodynamic resistance of rafting units of new design
Abstract
The article presents the results of experimental data analysis of the logs rafting units’ unsteady motion under the shallow waters effect. A float unit composed of four small volume bundles (up to 5 cubic meters) linked by the means of the fastening logs and flexible couplings has been proposed for rafting in shallow rivers. As the result of experimental research the mathematical model of hydrodynamic resistance was obtained. The timber transport units (TTU) included from 1 to 6 raft sections. The study was performed with a 1 : 20-scaled model. The length-to-width ratio of the TTU varied from 1 to 6. Froude scaling was performed over the range from 0.16 to 0.46 in case of uniform motion of the TTU. The experiments in unsteady motion conditions were performed using Froude scaling and Ho-criterion. The experiments were performed within the Reynolds number range of 3.1∙104…5.5∙105. The models were towed at speeds of 0.1…0.3 m/sec. Quadratic dependences of the water resistance force to the velocity of the uniform motion of the TTU models have been derived. The water resistance in the case of the TTU non-stationary motion is represented as the latter one for the uniform motion plus additional resistance arising during non-stationary motion. The values taken into account as the aggregated nonstationarity coefficient included: entrained water, body of water in the TTU cavities and additional water resistance. Dependences of the nonstationarity coefficient to the relative motion speed for all TTU models at the depth / draft ratios of 7.0; 5.0; 4.0; 2.7; 1.6 have been derived. The results obtained allow the researchers to determine the TTU acceleration time and starting course. Some additional tasks become solvable. For instance, necessary acceleration force for attainment of a TTU predetermined motion speed can be found.
Resources and Technology. 2024;21(4):150-164
150-164
A flail attachment to excavator ETC-208 for grubbing
Abstract
This article formulates the prerequisites used to select a base machine. The authors determine the requirements to be met by a machine with an interchangeable working body for grubbing in Siberian conditions. The article presents the research results of the working body performance attached to a machine. The tests were performed in production conditions at the facilities of the enterprise «Krasnoyarskvodstroy». The machine was taken to Bolshemurtinskiy district of Krasnoyarsk region to the reclamation object with large stumps. The purposes of these tests were to determine the expediency of using the excavator ETC-208 as a base for the stump grubbing, to determine the technical capabilities of the stump grinder in real operating conditions, to familiarize the machine operators with the new method and modernized machine for stump removal, to identify the need for such machines in the association «Krasnoyarskvodstroy». In contrast to the mock-up model, the new working body was equipped with a more reliable and easily replaceable fastening of cutters. After comprehensive testing at the production site to specify a number of parameters including cutting speed, this machine was put into operation. The advanced third sample of the working body ETC-208 was tested. It worked at the cutting chain speed from 1.5 to 2.5 m/sec, which immediately increased the productivity of machines by 1.5 times. The results of research showed the correctness of the chosen direction. It was found that the modernized machine worked quietly in the process of stump cutting. At the same time, the removal of a stump with a diameter of more than 0.9 m was made in two passes of the working body to a depth of 0.5—0.6 m. The length dimensions of shavings and chips did not exceed 0.2—0.3 m.
Resources and Technology. 2024;21(4):165-174
165-174