Analysis of Field View from Tractor and Trailer Units Using the Method of Terrestrial Laser Scanning

Having a proper view from the cabin of agricultural and forest machines is one of the main factors affecting work safety and efficiency. In forestry, machine operators very often perform working activities also in the rear of the cabin. Requirements, criteria and test procedures for the field of view from the tractor cabin are stipulated by the international technical standard ISO 5721. This study evaluates field view parameters from the cabin of the tractor (Valtra T 6300) and trailer (STS 12T) unit. In accordance with the test procedures, prescribed parameters were evaluated for the forward field of view; values for the rear field of view were determined in addition to outside the standard. In order to achieve more accurate measurements and faster evaluation of data, one of the latest methods-using laser pulse reflections (method of terrestrial laser scanning)-was employed. The results of our study demonstrate that even the construction of machines manufactured before the above-mentioned standard came to force can meet the current requirements, except for minor deviations.O

A Unique Grubbing Head Prototype for Environmentally Friendly and Sustainable Stump Removal

Stumps left behind after the felling of trees represent an important source of renewable energy that could be used for fuel mixtures as a sustainable solution. The subject of this research was to determine the influence of tree species, stump diameter size, and subsoil on the time required for stump processing. Evaluated parameters included the mean time for one stump's processing; the stump processing time based on the stump diameter; different soil types and tree species; and the tree species type (coniferous, broadleaved). The research was conducted in the territory of the Czech Republic in 2020/2021. There were 287 stumps and 6 tree species in total. The stumps were uprooted using a new prototype of grubbing head, developed at Mendel University in Brno, attached as an adapter on the boom of a JCB JS 220 LC excavator with a tracked undercarriage and was controlled remotely from an excavator cab. Research results confirmed that the processing time of one stump depends on the stump diameter (GLM), and the time needed for the processing of one stump increased with an increase in stump diameter in all experimental sites. An equation was suggested to predict the time needed to work on one stump.O

Harvesting and forwarding of trees with harvestor technology on railway protection zone lines

Předmětem monografie je technologický postup údržby dřevinných porostů v ochranných pásmech podél železničních dopravních cest a následný transport a úprava vytěžené dendromasy. Těžba dříví je dosud řešena na bázi použití přenosné motorové pily. Na strmých svazích pracovníci užívají poutací arboristické systémy. Je vyřešena nová technologie těžby náletových dřevin harvestorem umístěným na plošinovém železničním vozu, kterým je po železnici dopraven na pracoviště. Detailní postavení harvestoru ke kácenému stromu zajišťuje jeho pojezd po plošině železničního vozu. Soustřeďování a odvoz vytěžené dendromasy na úložné skládky pomocí forwarderu, umístěného a stabilizovaného na plošinovém železničním vozu, tvořícího součást zvláštní soupravy, do níž je zařazen minimálně ještě jeden železniční vůz s postranicemi. Vytěžená dendromasa je sbírána drapákem hydraulického jeřábu forwarderu a ukládána na jeho ložný prostor a do úložného prostoru sousedního vozu soupravy. Po naplnění ložných prostor souprava odjíždí na železniční stanici, kde je dendromasa desintegrována přistaveným štěpkovacím strojem a ukládána do ložného prostoru odvozní automobilové soupravy. Konečným produktem technologického postupu je energetická štěpka a v některých případech i výřezy pilařské, agregátové a vlákninové. Navrženým technologickým postupem je zkrácena doba uzavírky tratí, zvýšena bezpečnost pracovníků v těžbě náletových dřevin, požadováno vybavení pracovníků kvalifikačními osvědčeními pro dané práce. Dříví vytěžené z nárostů je zpeněženo se současným úklidem pracovišť a je zajištěna ekologická čistota prací.The monograph subject consists in the technological procedure of care of tree stands in protected zones along railway lines and the subsequent transport and adjustment of felled dendromass. So far, felling is carried out on the basis of portable power saws. On steep slopes, workers use arboristic equipment systems. A new technology has been worked out of self-seeding trees using a harvester placed on a plateau wagon, which is transported to a workplace by railway. The detailed position of the harvester to a felled tree is provided by its movement on the wagon plateau. Skidding and hauling the exploited dendromass to landings is carried out by means of a forwarder placed and stabilized on a plateau wagon creating the part of a special unit where another wagon with side boards was included. The felled dendromas s is collected by a grab of the forwarder hydraulic crane and placed on its loading space and into the stowage space of the unit neighbouring wagon. After filling the loading capacity the unit leaves for a railway station where the dedromass is disintegrated by a chipping machine and placed into the loading space of a logging truck-and-trailer unit. Final products of the technological procedure are fuel chips and in some cases also saw, aggregate and pulp logs. Through the proposed technological procedure, the time of the line closure is shortened, the safety of workers felling self-seeding trees is increased and the equipment of fellers by qualification certificates for given operations is required. Wood obtained from advance growth is realized together with cleaning the workplaces and the environmentally friendly operations are provided.Published Versio

Operating Characteristics of a Timber Trailer with a Hybrid Drive

This paper deals with the design and operational evaluation of a timber tractor-trailer unit with a hybrid trailer drive. The source of electrical energy for the two induction motors driving the front wheels of the tandem trailer axle is a battery, which is recharged by an induction machine operating as a generator during periods of a lower demand for power from the tractor diesel engine. An electric drive was designed for the defined working cycle of the tractor-trailer unit, and its loading characteristics were tested in the laboratory. The parameters measured on the field tests during timber forwarding were battery voltage and power, and the energy balance. Three adjustment levels of the potentiometer controlling the trailer hybrid drive (50, 75 and 100%) were tested at three different forwarding distances of 100, 500 and 1000 m. Additionally, any slippage of the prime mover wheels and trailer was measured. The maximum peak power taken from the battery was ca. 33 kW during the field tests, whilst the drive was able to deliver a peak output of up to 72 kW for 10 s and permanently up to ca. 50 kW. Even in harsh terrain conditions, the electric drive assisted the combustion engine only when the loaded tractor-trailer unit was travelling uphill. The hybrid drive operation was sustainable for the whole working shift, without the need for recharging when the potentiometer was set to 50%. This appropriate setting of the potentiometer controlling the trailer's hybrid drive reduced the slipping of the driven wheels of the tractor-trailer unit whilst travelling uphill.O

New technology for logging stumps for energy purposes

Pařezy, které zůstaly po kácení stromů, představují významný zdroj obnovitelné energie, který by mohl být využit pro palivové směsi jako udržitelné řešení. Předmětem tohoto výzkumu bylo zjistit vliv druhu stromu, velikosti průměru pařezu a podloží na dobu potřebnou pro zpracování pařezu. Hodnocené parametry zahrnovaly průměrnou dobu zpracování jednoho pařezu; dobu zpracování pařezu v závislosti na průměru pařezu; různé typy půdy a druhy stromů; a druh stromu (jehličnatý, listnatý). Výzkum probíhal na území České republiky v letech 2020/2021. Celkem bylo zpracováno 287 pařezů a 6 druhů stromů. Pařezy byly vytrhávány pomocí nového prototypu klučící hlavice, vyvinutého na Mendelově univerzitě v Brně, který byl připevněn jako adaptér na výložník rýpadla JCB JS 220 LC s pásovým podvozkem a byl ovládán dálkově z kabiny rýpadla. Výsledky výzkumu potvrdily, že doba zpracování jednoho pařezu závisí na průměru pařezu (GLM) a doba potřebná ke zpracování jednoho pařezu se na všech pokusných stanovištích zvyšovala s rostoucím průměrem pařezu. Byla navržena rovnice pro předpověď času potřebného ke zpracování jednoho pařezu.Stumps left behind after the felling of trees represent an important source of renewable energy that could be used for fuel mixtures as a sustainable solution. The subject of this research was to determine the influence of tree species, stump diameter size, and subsoil on the time required for stump processing. Evaluated parameters included the mean time for one stump's processing; the stump processing time based on the stump diameter; different soil types and tree species; and the tree species type (coniferous, broadleaved). The research was conducted in the territory of the Czech Republic in 2020/2021. There were 287 stumps and 6 tree species in total. The stumps were uprooted using a new prototype of grubbing head, developed at Mendel University in Brno, attached as an adapter on the boom of a JCB JS 220 LC excavator with a tracked undercarriage and was controlled remotely from an excavator cab. Research results confirmed that the processing time of one stump depends on the stump diameter (GLM), and the time needed for the processing of one stump increased with an increase in stump diameter in all experimental sites. An equation was suggested to predict the time needed to work on one stump.Published Versio

Innovative technology of saplings planting for increase tourism potential of the landscape

The saplings extractor is intended primarily for replanting all types of seedling forest trees included a bale of soil without disturbing the root system. Trees growing along roads or already grown to a certain extent trees in the landscape are often need to be transplanted due to landscaping or urban planning. These trees can be used, for example, in popular tourist localities, where they can speed up the regeneration of the landscape and make visitors' stay more pleasant. However, this activities shouldn't be provided only manually, but some advanced technologies have to be used. The goal of this paper is presenting a new technology for mechanized planting using the production potential of the seedling trees. The principle of the saplings extractor lies in excavating a pit at the site that will be the subject of tree replanting, and then transplanting the pre-lifted up seedling forest tree into the prepared excavated pit. The last phase is to backfill the pit all around with soil from the excavated pit after the sapling was picked up. This paper emphasise the economic advantages of new technology and provides the saplings planting solutions in the form of landscaping, road tree rows or ornamental trees in an urbanized environment.Published Versio

Analysis of Field View from Tractor and Trailer Units Using the Method of Terrestrial Laser Scanning

Having a proper view from the cabin of agricultural and forest machines is one of the main factors affecting work safety and efficiency. In forestry, machine operators very often perform working activities also in the rear of the cabin. Requirements, criteria and test procedures for the field of view from the tractor cabin are stipulated by the international technical standard ISO 5721. This study evaluates field view parameters from the cabin of the tractor (Valtra T 6300) and trailer (STS 12T) unit. In accordance with the test procedures, prescribed parameters were evaluated for the forward field of view; values for the rear field of view were determined in addition to outside the standard. In order to achieve more accurate measurements and faster evaluation of data, one of the latest methods—using laser pulse reflections (method of terrestrial laser scanning)—was employed. The results of our study demonstrate that even the construction of machines manufactured before the above-mentioned standard came to force can meet the current requirements, except for minor deviations

A Unique Grubbing Head Prototype for Environmentally Friendly and Sustainable Stump Removal

Stumps left behind after the felling of trees represent an important source of renewable energy that could be used for fuel mixtures as a sustainable solution. The subject of this research was to determine the influence of tree species, stump diameter size, and subsoil on the time required for stump processing. Evaluated parameters included the mean time for one stump’s processing; the stump processing time based on the stump diameter; different soil types and tree species; and the tree species type (coniferous, broadleaved). The research was conducted in the territory of the Czech Republic in 2020/2021. There were 287 stumps and 6 tree species in total. The stumps were uprooted using a new prototype of grubbing head, developed at Mendel University in Brno, attached as an adapter on the boom of a JCB JS 220 LC excavator with a tracked undercarriage and was controlled remotely from an excavator cab. Research results confirmed that the processing time of one stump depends on the stump diameter (GLM), and the time needed for the processing of one stump increased with an increase in stump diameter in all experimental sites. An equation was suggested to predict the time needed to work on one stump