Design, construction and evaluation of a vibration absorber for grain loss monitoring system of combine harvesters

Using grain loss monitor system is one of the ways to measure the amount of the grain loss in the combine harvesters. The piezoelectric sensors that have a very great sensitivity are usually used in this kind of systems. Combine vibrations prevent proper and certain function of these sensors during the harvesting process. And it is necessary to prevent the transmission of these vibrations to grain loss monitor system in order to reduce the interference of the combine vibrations on the systems performance. Therefore, it is essential to use vibration absorbers before installing the measuring device on the combine harvester. In this study after designing of a vibration damping absorber, its differential equations were obtained. Then, the frequency response function of the system was obtained considering the external harmonic excitation and the effect of various parameters were examined. Finally, the performance of the designed vibration absorber was demonstrated with experimental tests. The results indicated that the designed vibration absorber had a high efficiency and resulted in 99% reduction of the acceleration transferred from combine to the sensor. The results of this study can be applied in designing and construction of vibration absorbers.