Forests

Research

12 pages, 2232 KiB

Open AccessArticle

Anthropometric Analysis of Selected Body Dimensions and Comparison with the Design Approach for Forestry and Agricultural Machine Operators

by Miloš Gejdoš, Miloš Hitka and Žaneta Balážová

Forests 2021, 12(8), 1038; https://doi.org/10.3390/f12081038 - 05 Aug 2021

Cited by 1 | Viewed by 4857

Abstract

The aim of the study was to conduct an analysis of selected anthropometric measurements of sitting posture of the adult male population and to compare the results to the workplace of earthmoving machine operators. Research into this problem is important in several respects, [...] Read more.

The aim of the study was to conduct an analysis of selected anthropometric measurements of sitting posture of the adult male population and to compare the results to the workplace of earthmoving machine operators. Research into this problem is important in several respects, particularly the design approaches taken for the current and future machines, and their impact on the health and safety of operators. The anthropometric analysis was based on dimension measurements of the adult male population gathered in the years 2002–2019. The sample consisted of 1702 subjects aged 18 to 25. Thirteen body dimensions were selected and evaluated according to the European Standard of International Organization for Standardization (EN ISO) Nr. 3411. Anthropometric analysis of individual dimensions was evaluated using descriptive statistics and frequency histograms. The results of the analysis were compared to values recommended in the EN ISO 3411 standard. Results confirmed the growing trend of specific human dimensions within the adult population. In eight of the 13 analyzed body dimensions, descriptive statistics showed above-average values in the analyzed population compared to the values given in the standard. The long-term trend commonly observed in the adult population of developed countries was also confirmed. Full article

(This article belongs to the Special Issue Forestry Production Process Automation and Robotization)

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13 pages, 2124 KiB

Open AccessArticle

Estimation of Productivity and Costs of Using a Track Mini-Harvester with a Stroke Head for the First Commercial Thinning of a Scots Pine Stand

by Krzysztof Leszczyński, Arkadiusz Stańczykiewicz, Dariusz Kulak, Grzegorz Szewczyk and Paweł Tylek

Forests 2021, 12(7), 870; https://doi.org/10.3390/f12070870 - 30 Jun 2021

Cited by 5 | Viewed by 1867

Abstract

The aim of the present work was to estimate the productivity and costs of timber harvesting and forwarding during the first commercial thinning of a Scots pine stand. Three harvesting models were introduced and compared: narrow trail, wide access trail, and schematic extraction. [...] Read more.

The aim of the present work was to estimate the productivity and costs of timber harvesting and forwarding during the first commercial thinning of a Scots pine stand. Three harvesting models were introduced and compared: narrow trail, wide access trail, and schematic extraction. The analyzed harvesting equipment consisted of a track mini-excavator (34 kW) with a stroke harvester head (gripping range 4–30 cm), and a farm tractor coupled to a logging trailer with a hydraulic crane. Merchantable timber (roundwood with a minimum diameter of 5 cm inside bark) was harvested from a 25-year-old planted Scots pine stand growing on a grid of 1.4 m × 1.8 m. The study showed the productivity of the mini-harvester ranged from 3.09 to 3.47 m³/PMH₁₅ (productive machine hours plus 15 min), and that of the forwarding equipment to be 4.07 m³/PMH₁₅. The analyzed model of productivity as a function of tree volume and thinning intensity was statistically significant, but the intensity parameter was significant only on plots located along wide access trails (3.7 m) and insignificant on plots located along narrow access trails (2.5 m). The distance between trees was not found to be significant. The calculated net machine costs for the forwarding equipment and track mini-harvester were EUR 36.12 and 52.47 per PMH, respectively. An increase in the usage rate of the harvesting equipment to 80% would reduce the harvesting and forwarding costs to EUR 22.07/m³. Full article

(This article belongs to the Special Issue Forestry Production Process Automation and Robotization)

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18 pages, 3110 KiB

Open AccessArticle

Detection of Scots Pine Single Seed in Optoelectronic System of Mobile Grader: Mathematical Modeling

by Arthur Novikov, Viсtor Lisitsyn, Mulualem Tigabu, Paweł Tylek and Sergey Chuchupal

Forests 2021, 12(2), 240; https://doi.org/10.3390/f12020240 - 20 Feb 2021

Cited by 11 | Viewed by 1605

Abstract

The development of mobile optoelectronic graders for separating viable seeds by spectrometric properties with high detection accuracy represents a very relevant direction of development for seed handling operations. Here, the main parameters of the radiation source and receiver for detecting a single seed [...] Read more.

The development of mobile optoelectronic graders for separating viable seeds by spectrometric properties with high detection accuracy represents a very relevant direction of development for seed handling operations. Here, the main parameters of the radiation source and receiver for detecting a single seed in the diagnostic system of a mobile grader were modeled based on the principles of technical optics using Scots pine (Pinus sylvestris L.) seeds as a case study. Among the pine seeds in the seed batch, there are fossilized and empty seeds that are exactly the same in geometric and gravitational parameters as live seeds. For their separation from the seed batch, data from spectrometric studies in the near-infrared (980 nm) region can be used. To substantiate the parameters of the light source, a geometric optical model of optical beam formation was considered, while the energy model of optical beam formation was considered to substantiate the parameters of the light detector. The results of this study show that the signal value depended on the orientation of a single seed relative to the recording window. The beam angle from the radiation source should be within 45 degrees. The difference between the optical streams should be 50 microns, which made it possible to clearly detect the signal at a standard noise level of 15 microns and signal-to-noise detection accuracy ratio of 56.3 dB. This study expands theoretical knowledge in the field of the spectrometric properties of a single seed, considering the cases of its orientation relative to the optical beam, which affected the effective area of detection of the seed. The obtained data on the location of the main elements of the diagnostic system will speed up the design of mobile optoelectronic graders, and the development of a contemporary protocol for improving Scots pine seed quality. Full article

(This article belongs to the Special Issue Forestry Production Process Automation and Robotization)

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16 pages, 4889 KiB

Open AccessArticle

Perception of the Harvester Operator’s Working Environment in Windthrow Stands

by Grzegorz Szewczyk, Raffaele Spinelli, Natascia Magagnotti, Bartosz Mitka, Paweł Tylek, Dariusz Kulak and Kamil Adamski

Forests 2021, 12(2), 168; https://doi.org/10.3390/f12020168 - 31 Jan 2021

Cited by 9 | Viewed by 1762

Abstract

The aim of the study was to determine the mental workload of a harvester operator when working in late thinning and in windthrown stands of the same type and age, using eye movement patterns as an indicator. Eyeball movement variability was analysed using [...] Read more.

The aim of the study was to determine the mental workload of a harvester operator when working in late thinning and in windthrown stands of the same type and age, using eye movement patterns as an indicator. Eyeball movement variability was analysed using the eye tracking method. The mean duration of eyesight fixations in windthrown stands was shorter than in the control undamaged stands by about 20% (444 ms and 534 ms, respectively). The mean time of eyesight movements (saccades) in the windthrown stands was shorter than in the control undamaged stands by approx. 15%. The largest differences between the duration of saccades in the windthrown and control stands were observed between the cutting of trees and cutting logs off their root plates: the saccades were longer by about 20% when working in the control stands (49 ms) as compared to the windthrown stands (43 ms). Large differences in the duration of saccades between the windthrown area (42 ms) and the control area (47 ms) were also found when travelling between successive operation sites. In both types of stands, the shortest saccades were observed during processing: 39 ms. Summary durations of saccades observed during the processing of successive trees occurred in sequences showing repeated periods of variable eyeball activity, where longer saccades were followed by shorter ones. Documented more variability of eyesight activities of the harvester operator performing the operations of processing and moving is new standard of eye balls activities for the more taxing work conditions presented by windthrown stands. Full article

(This article belongs to the Special Issue Forestry Production Process Automation and Robotization)

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9 pages, 1550 KiB

Open AccessArticle

2D Photogrammetry as a Forwarder Load Measurement Technique

by Ondřej Nuhlíček, Martin Slavík and Jiří Dvořák

Forests 2020, 11(9), 962; https://doi.org/10.3390/f11090962 - 02 Sep 2020

Cited by 1 | Viewed by 1695

Abstract

Research Highlights: In this study, we present the use of time-lapse photos as a way to estimate the height of the load on the forwarders. This approach, using nonprofessional outdoor cameras, is a cheap and time-effective solution for continuous load height measurements, and [...] Read more.

Research Highlights: In this study, we present the use of time-lapse photos as a way to estimate the height of the load on the forwarders. This approach, using nonprofessional outdoor cameras, is a cheap and time-effective solution for continuous load height measurements, and it offers at least the same accuracy as a gauge measurement. This method represents another approach to the automation of time studies in forestry. Background and Objectives: Time studies require information about the load on the forwarders. Until now, this information was obtained either by using a gauge measure, sampling of the load, or averaging the load from large area datasets. More accurate methods like laser scanning are costly and fragile. During time study preparations, we suggested a robust system of measuring the load height and tested it against the commonly used gauge measuring technique. Materials and Methods: Two cameras took pictures of the load; these photos were processed for camera lens distortion and rectified into the cartesian coordinate system, and the height of the load was calculated. These values were then tested against gauge measured values using paired t-test. Results: Straight line distance calculated from the images and the gauge-measured distance did not show a significant difference (p-value 0.9354). Calculated vertical distance was, however, significantly different from the calculated straight-line distance (p-value of 0.0015), suggesting possible bias of the gauge measured distance. The root mean square error (RMSE) of the rectification process was, on average, 0.42 cm. Conclusions: The proposed method was verified to correspond with the gauge measure method; however, our research raised the question of the gauge method reliability, as the taken measurements are not perfectly vertical, and for the correct load estimation, the vertical distance is needed. We, therefore, conclude that for this photogrammetry method, the vertical, rather than straight-line, distance should be used. The presented solution can be used for long-term data collection without interrupting the whole forwarding process for taking the load measurement. The longer data processing in office enables researchers to spend less time in the field taking hand measurements. Full article

(This article belongs to the Special Issue Forestry Production Process Automation and Robotization)

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19 pages, 7417 KiB

Open AccessArticle

Simulation Models of Skidder Conventional and Hybrid Drive

by Juraj Karlušić, Mihael Cipek, Danijel Pavković, Juraj Benić, Željko Šitum, Zdravko Pandur and Marijan Šušnjar

Forests 2020, 11(9), 921; https://doi.org/10.3390/f11090921 - 23 Aug 2020

Cited by 8 | Viewed by 2796

Abstract

The paper presents a hypothetical conversion of a conventional cable skidder powertrain to its hybrid version. Simulations of skidder operation were made for two existing forest paths, based on the technical characteristics of the engine, transmission system and the characteristics of the winch. [...] Read more.

The paper presents a hypothetical conversion of a conventional cable skidder powertrain to its hybrid version. Simulations of skidder operation were made for two existing forest paths, based on the technical characteristics of the engine, transmission system and the characteristics of the winch. Fuel and time consumption were calculated per working cycle considering the operating conditions (slope, load mass). The model was then converted to a hybrid version by adding a battery energy storage system in parallel with the electrical power generator and by employing an energy management control strategy. The dimensions of the battery and the power generator were chosen based on the characteristics of the existing winch with the aim of completely taking over its operation. The management strategy was selected using the specific fuel consumption map. All simulations were repeated for the hybrid drive under the same operating conditions. The results show that fuel savings of around 13% can be achieved with the selected hybrid drive and steering strategy. Full article

(This article belongs to the Special Issue Forestry Production Process Automation and Robotization)

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14 pages, 9048 KiB

Open AccessArticle

The Innovative Design of the Fire-Fighting Adapter for Forest Machinery

by Richard Hnilica, Miroslava Ťavodová, Michaela Hnilicová, Jaroslav Matej and Valéria Messingerová

Forests 2020, 11(8), 843; https://doi.org/10.3390/f11080843 - 04 Aug 2020

Cited by 4 | Viewed by 2644

Abstract

The presented article presents an innovative solution of a fire-fighting adapter based on the basic hypothesis: to provide sufficient technical support in difficult terrain conditions for water transport logistics in order to quickly prevent the spread and destruction of forest fire. At present, [...] Read more.

The presented article presents an innovative solution of a fire-fighting adapter based on the basic hypothesis: to provide sufficient technical support in difficult terrain conditions for water transport logistics in order to quickly prevent the spread and destruction of forest fire. At present, when forest fires begin, it is often quite complicated to provide sufficient technical support for the quick prevention and elimination of fires. This fact is largely eliminated by the designed fire-fighting adapter. The mentioned fire-fighting adapter can be used as a fire-fighting mobile device with a base machine of a forest wheeled skidder (LKT), part of the long-distance transport of water in difficult terrain (lake system), a water tank in difficult terrain with the possibility of filling the Bambi bag with a helicopter, part of the long-distance transport of water in the case of a difficult water source without a forest access road network, and a mobile device for emergency transportation of materials in difficult terrain. In addition to the use for fighting forest fires, the fire adapter can also be used to provide for transport of water for forest nurseries (irrigation), freshly planted areas in the event of prolonged drought, the filling of watering-places for forest animals and filling puddles in the dry season. When designing the supporting frame, we used and imitated the evolutionary approach of nature in the form of generative design. The presented paper deals with the use of modern composite materials in the design of superstructures for base machines, which gradually acquire meaning. The main reason for the increasing use of fiberglass is to achieve higher strength and safer weight reduction. This adapter is designed for forest wheel tractors that reach 40% slope availability, are able to work on the stand area, overcome obstacles and are available in sufficient quantities in all Slovak forest areas. Full article

(This article belongs to the Special Issue Forestry Production Process Automation and Robotization)

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16 pages, 3546 KiB

Open AccessArticle

Estimation of Over- and Under-Bark Volume of Scots Pine Timber Produced by Harvesters

by Monika Sedmíková, Radim Löwe, Martin Jankovský, Pavel Natov, Rostislav Linda and Jiří Dvořák

Forests 2020, 11(6), 626; https://doi.org/10.3390/f11060626 - 02 Jun 2020

Cited by 8 | Viewed by 2508

Abstract

Harvesters produce one third of timber in Czechia. The aim of this study was to analyze the over- and under-bark volume estimates of Scots pine (Pinus sylvestris L.) timber produced by a mid-performance harvester. The data were collected between March 2017 and [...] Read more.

Harvesters produce one third of timber in Czechia. The aim of this study was to analyze the over- and under-bark volume estimates of Scots pine (Pinus sylvestris L.) timber produced by a mid-performance harvester. The data were collected between March 2017 and June 2018. In total, 4661 stems cut into 29,834 logs were analyzed. For volume estimation, StanForD offers several price categories using various algorithms. Three of these price categories are relevant for Czech forestry—M3s, M3toDE, and M3miDE. The M3s price category is based on the estimation of partial volumes of 10 cm long sections, which are summed. Therefore, this price category represents the volume estimation closest to the true volume. By comparison, the M3toDE and M3miDE price categories use the same algorithm for volume estimation, which is based on the Huber formula using a midspan diameter rounded down to the nearest whole centimeter. The M3toDE price category underestimated the over-bark volume by 6.48% compared to the reference price category M3s. The mean log volume estimated through the M3s price category was significantly higher than the M3toDE volume both in individual grades and without grading. We found significant differences between under-bark volume estimates by the diameter band bark deduction method (DBM) and the parametric linear bark deduction method (PLM) used in harvester’s systems according to the Guidelines for Electronic Scaling of Timber for Harvesters in Czechia (GEH) for Scots pine butt logs with rough bark, and also for other logs with normal bark thickness. To obtain under-bark volume estimates of Scots pine timber that are comparable with the Guidelines for Timber Scaling in Czechia (GTS) using the parametric nonlinear bark deduction method (PNM), we recommend using the algorithm of the M3toDE price category, with double bark thickness determined by the diameter band bark deduction method. Full article

(This article belongs to the Special Issue Forestry Production Process Automation and Robotization)

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