Construção de uma bancada de ensaio e avaliação de um sistema de mensuração da produtividade de grãos. / Construction of a laboratory bench and evaluation of a grain yield monitor.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

With the progress of the precision agriculture where spatial yield variability is taken into account, it is necessary to improve data collection so the results can be more reliable. It is necessary to understand how yield sensor used on combines works in order to know the accuracy of the field data for generation of the yield maps. This work aims to characterize the performance, under controlled conditions, of a commercial equipment, its yield sensor and interactions with the hillside sensor, forward speed sensor and grain moisture sensor. A test bench with a tank feeder was built with a variable opening floodgate, which drains grains to the foot of the paddle elevator of a commercial combine. The grain flow transported by the elevator pass through the yield and moisture sensor and is unloaded in a superior tank hold by a load cell with capacity of 2.000kg (desconsidering the variation of the gravity) so that the mass data is compared with that registered by the monitor. The monitor was tested on simulations of constant and variable flow rates in three different transverse positions of the elevator. The results showed that the test bench was shown efficient for the types of proposed tests. Its structure is resistant and the variation of the angle of the elevator is of easy handling. The geometry of the feeding tank was shown efficient to supply uniform flow rates, between 2,0 and 8,0kg.s-1. The speed sensor showed relative mean error of 0,31% and the moisture sensor presented a module mean error of 5,01%. Flow estimation got worst increasing or decreasing the flow rate apart from calibration region. Main mean error of the test with constant flow rates was of -5,31%, with standard deviation of 4,14. On 70% of the test monitor, readings resulted in erros less than 6,00% with constant flow. Its readings overestimated flow values under the mean flow rate of calibration and underestimated flow above it. The readings of the yield monitor responded to the variations imposed to the flow through by the elevator immediately. The hillside sensor and the algorithm that considers the inclination are efficient for compensating the transverse inclinations of the machine, even in conditions of varied flow rates. The general mean error test with varied flow rates, was 4,84%. The global mean error shown by the yield monitor for the readings with varied and constant flow rates was 5,12%.

ASSUNTO(S)

spatial variability precision agriculture yield agricultura de precisão máquinas agrícolas agricultural machinery produtividade variabilidade especial

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