A study of a barometric methodology for assessing the agricultural and forestry machine’s seat comfort

The agricultural operations carried out with machines, require the operator spends a substantial amount of hours in a seated position on a seats often not properly padded therefore the parts of the body in contact with the seat are subject to considerable stresses. In addition, the operator must not only control the task he has done but he must also continually monitor actively with a significant commitment to operate levers, buttons and steering. Therefore, the operator's body is subject to various twists carried out in dynamic conditions according to the crop processing to perform. The parts of the body in contact with the seat, in particular the buttocks and the back, receive continuously, at irregular intervals, and with different intensity, different mechanical stresses that are translated immediately in pressure to the them tissues. Often these compressions occur in a concentrated manner, especially if the body is skinny and therefore the pressures could immediately affect the comfort perceived by the operator and at a later time, if repeated by the same operator and with the same machine, they could degenerate into occupational diseases because of the possible an incidence on blood flow. The purpose of this paper is to propose a new methodology based on barometric mapping, to investigate how forces are applied to the back and buttocks while driving a tractor, under standardized test conditions. In particular, the experimental tests have been conducted on a smooth surface free of roughness which is the simplest movement a vehicle can do along a road, such as transporting a trailer. The data were collected through an acquisition system based on a carpet with small pressure sensors. It has been used a carpet of 1024 cells for the sitting and one for the backrest. Acquisitions between the two sides of the seat were synchronized and the tests were repeated five times in order to develop an adequate analysis. Statistical analysis was mainly aimed at verifying the variability among datasets in order to study the effect of the seat on the value recorded. The statistical analysis was mainly aimed at verifying the variability between the data sets to study the effect of the seat on the pressure value recorded. The results showed, for the observed correlations, this method based on pressure between the seat and the body is a good tool to help the valuation judgment of a seat