Tag Archives: drawbar pull

261-274 R. Kägo, P. Vellak, H. Ehrpais, M. Noorma and J. Olt
Assessment of power characteristics of unmanned tractor for operations on peat fields
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Assessment of power characteristics of unmanned tractor for operations on peat fields

R. Kägo¹²*, P. Vellak¹², H. Ehrpais²³, M. Noorma² and J. Olt¹

¹Estonian University of Life Sciences, Institute of Technology, F.R. Kreutzwaldi 56/1, EE51014 Tartu, Estonia
²Milrem Robotics, Betooni 1, EE11415 Tallinn, Estonia
³University of Tartu, Tartu Observatory, Observatooriumi 1, EE61602 Tõravere, Estonia
*Correspondence: riho.kago@emu.ee

Abstract:

In this article, power characteristics of a state-of-the-art unmanned ground vehicle (UGV) are characterised. It is demonstrated that in terms of power characteristics requirements, purpose-built computer aided autonomous UGV systems are capable of replacing systems that utilise conventional tractors in peat field operations, with milled peat extraction operations as a case study. The authors demonstrate the viability of the UGV in achieving optimal mobility capabilities in operating on peatland surface. The UGV of interest was assessed for two operations of milled peat extraction: milling and harrowing. For both operations, the power consumption of the UGV and the drawbar pull of the implements (passive miller and harrower) were measured and analysed. The required drawbar pull values of the investigated implements remained in the range of 4–8 kN, which corresponded to the drawbar power of 14–36 kW. It was found that the UGV of interest is capable of carrying out milled peat operations in terms of traction capacity. However, it was found that the power supply capacity to be insufficient, thus requiring an improved solution.

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333–342 R. Abrahám, R. Majdan and R. Drlička
Special tractor driving wheels with two modification of spikes inclination angle
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Special tractor driving wheels with two modification of spikes inclination angle

R. Abrahám¹*, R. Majdan¹ and R. Drlička²

¹Department of handling and transport machinery, Faculty of Engineering, Slovak University of Agriculture in Nitra, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
²Department of Quality and Engineering Technologies, Faculty of Engineering, Slovak University of Agriculture in Nitra, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak
*Correspondence: rudolf.abraham@uniag.sk

Abstract:

The paper presents a research on an improvement of tractor drawbar properties using special driving wheels. Two modifications of the special driving wheels were designed and tested under field conditions. The results were compared with standard tyres. The special driving wheels consists of the tyres with a modified tyre-tread pattern and equips with the spike segments. The special driving wheels allow to activate or deactivate the spike segments to improve a drawbar pull at worse adhesive conditions of the ground or transport on roads with standard tyres. The first modification activates all 8 spike segments at spike inclination angle 90° and the second one 4 at angle 90°and 4 at 30°. The measurements were realised in October 2017 in an area of the Slovak Agricultural Museum in Nitra. The drawbar properties of the special driving wheels were evaluated based on drawbar pull of the test tractor Mini 070 type connected with a load tractor MT8-065 type. Using the test tractor in 1st and 2nd gear, the measurements were realized at 100% wheels slip and repeated 4 times. The results show the statistically significant differences in the drawbar pull of the test tractor with different driving wheels on a grass plot. The highest increase in drawbar pull reached the value 25.56% (2nd gear) and 19.98% (1st gear) in case of the special driving wheels with 4 spike segments at 90° and 4 at 30°. In case of the special driving wheels with 8 spike segments at 90°, increase in the drawbar pull reached the value 10.09% (1st gear) and 15.21% (2nd gear) in comparation with the standard tyres.

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621-633 R. Abrahám, R. Majdan and R. Drlička
Comparison of consumption of tractor at three different driving wheels on grass surface
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Comparison of consumption of tractor at three different driving wheels on grass surface

R. Abrahám¹*, R. Majdan¹ and R. Drlička²

¹University of Agriculture in Nitra, Faculty of Engineering, Department of Transport and Handling, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
²Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Quality and Engineering Technologies, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
*Correspondence: rudolf.abraham@uniag.sk

Abstract:

The paper deals with possibility of reduction of tractor fuel consumption when working on grass surface, and compares use of two versions of spike devices embedded to the original tyre body. The device was designed at Department Transport and Handling (Slovak University of Agriculture in Nitra). Older as well as newer system proposed in 2017 comprises spikes and it is assembled to common tractor tyre tread pattern with auxiliary grooves cut in. Same device can be set to two positions, allowing to work as 8-spikes and 16-spikes system. The spikes are tilted in grooves when moving on paved road. The spikes are ejected out to reduce wheels slip when operated in field. Remaining eight spikes are tilted in case of 8-spikes system. Measurements were realised on grass surface. Tractor Mini 070 type was loaded with heavier tractor MT8-065 type in tests with 3 different driving wheels, balancing the actual weight in all cases. Drawbar pull and fuel consumption were measured in tests, allowing to compute specific drawbar consumption and fuel consumption per hour for three different loads. The results pointed out a fact the tyre slip loss and energy consumption of tractor movement increase at the soil humidity 19.45%. It follows from results achieved that use of both 8- and 16-spikes wheel device versions reduced fuel consumption when cultivating higher humidity soil, preferable for tillage. Eight spikes system with semi-tilted remaining spikes is the most efficient method.

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7-16 R. Abrahám, R. Majdan, T. Šima, J. Chrastina and J. Tulík
Increase in tractor drawbar pull using special wheels
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Increase in tractor drawbar pull using special wheels

R. Abrahám¹, R. Majdan¹, T. Šima²⋅*, J. Chrastina¹ and J. Tulík¹

¹Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Transport and Handling, Tr. A. Hlinku 2, 949 76 Nitra, Slovak Republic 2Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Machines and Production Systems, 949 76 Nitra, Slovak Republic; *Correspondence: tomasko.sima@gmail.com

Abstract:

The paper is aimed at the possibility of increasing in maximal drawbar pull of tractor working on the soil. The increasing in drawbar pull occurred due to a special wheels mounted on drive axle. The special wheels were equipped with auto-extensible blades and designed in Slovak university of agriculture in Nitra. The main advantage of the special wheels is the automatic extension of steel blades to increase the drawbar pull during a wheel slip and automatic return to the base position to allow the transport of tractor by the route. The testing operation points at the increase in drawbar pull resulting in decrease of wheel slip. A drawbar pull of tractor equipped with standard tires and special wheels was compared on the different soil moisture condition. The higher increasing in drawbar pull was measured during the tractor operation on the soil with higher moisture in comparison the soil with lower moisture level. In case of soil moisture 14% the increase in drawbar pull of tractor equipped with special wheels reached the value 17.2% in compare with standard tires. Using the special wheels on the same field with higher level of soil moisture 22% the increase in drawbar pull reached the value 36.1% in compare with standard tires.

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