Jiri Masek, Milan Kroulik, Zdenek Kviz, Vaclav Prosek Czech ...

ENGINEERING FOR RURAL DEVELOPMENT Jelgava, 26.-27.05.2011.
By monitoring these parameters the yield maps can be created. Spatially-related data of
throughput of the material were recorded in the data logger. Pulses of a potentiometer and machine
position from DGPS receiver were at the same time recording to the data logger, too. The recording
interval was set to 2 s.
1
2
3
Fig. 1. Location potentiometer on the belt tensioning mechanism: 1 – belt tension roller
mechanism; 2 – connecting rod; 3 – potentiometer
Results and discussion
The trial measurement was carried out in the selected field and started by pressing the arranged
discontinuous row as it was explained above (Fig. 2). This step was taken as a calibration procedure.
Based on the results of the calibration potentiometer the calibration curve was obtained. Depending on
the number of pulses during the potentiometer and net weight of the package best fits the exponential
curve with equation y=2745·1e -0.002x . The graph in Figure 3 shows the calibration curve.
Number of pulses
3000
2500
2000
1500
0 20 40 60 80 100
Time progress, s
Number of pulses
2900
2700
2500
2300
2100
1900
1700
1500
y = 2745.1e -0.002x
R 2 = 0.9994
0 50 100 150 200 250
Weight of bale, kg
Fig. 2. Course of data record during
discontinuous straw row pressing
Fig. 3. Calibration curve
By pressing forage with a variable press chamber machine uniform compressibility of the bale
with increased volume (diameter) of the bale is achieved. The increased volume of the bale recorded
by the potentiometer is proportional to the increasing of the bale weight. Figure 4 shows the time
series record of the measurement of the growth package. For the subsequent processing of each set the
yield t·ha -1 gradually increases. Prior to the processing of the data set it was necessary to exclude
values that were recorded during the tensioning mechanism for returning a package to the starting
position and the value recorded on headlands. Also a point where the package is bound has to be
excluded from the data set. After processing, the record has been found in straw yield values ranging
from 1.5 to 7.3 t·ha -1 with an average of 4.4 t·ha -1 .
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