Comparison of methods for measuring draught force of tractor during soil tillage

The aim of this paper is to compare two methods of draught force measurement during field tests.Energy demands of the soil tillage machines are an important factor for the choice of machinery, further development and improvement.A common method of measurement is to use a measuring rod with a tensometric sensor.Using of two tractors is a disadvantage of this method.Inaccuracy is also entered due to rolling resistance of the drawn tractor.A special measuring frame has been developed for the replacement of conventional methods.The frame was developed in cooperation Czech University of Life Sciences in Prague and Bednar FMT companies.Sets of machines were used for the evaluation: the track tractor JD 8320 RT as a pulling tractor, measuring frame located on the tractor´s three point hitch, measuring rod frame for frame working control and the wheel tractor NH T7050, and the tines cultivator (Köckerling Exact Gruber Vario, 4,8 m working width).During comparison of the draught force values from the strain gauge load cell located on the new developed measuring frame with the values from the standard device (measuring rod) it was detected that there is not statistical difference between the both methods.The new method with the measuring frame could be used for the purpose of measurement of the draught force (typically for soil tillage machines).We do not have to solve a question about the pulled tractor in this case.This measurement is easier for testing.The testing without the pulled tractor eliminated errors in the application of the classical methods (rolling resistance of the drawn tractor).