Proposition of an Integrated Ergonomic Indicator (IEI) in the assessment of forest machines

Ergonomic assessments in forest operations are performed in isolation due by of lack of an adequate methodology that correlates the ergonomic variables simultaneously. The objective this work was to propose new methodology for the ergonomic evaluation of forest machines, by the development of an Integrated Ergonomic Indicator (IEI), useful to relate ergonomic variables.

Vibration, noise, heat, luminosity, posture, repeatability, visibility and productivity data were obtained during the day and night periods of the feller buncher, harvester, forwarder, skidder and processor in the Parana State, Brazil. 

The values, normalized by their deviations from the mean were subjected to factorial multivariate analysis determining the factors that would influence the IEI composition. 

The factor index was multiplied by the explained variance for each factor and the result was divided by the total variance explained, so that the values remained around 0 and the higher the result, the worse the ergonomic condition. 

The evaluation presented R² of 0.9 and the variables that most influenced were vibration, noise and lateral visibility, relating to each other. 

The worst machine was the skidder in both work shifts, with IEI of 2.82 for the daytime period and 1.60 for the night, due to impacts and bumps in its displacement added to the high percentage of worker time with the rotated neck. 

The best machine were harvester B and processor at night with IEI of -1.36 and -0.96, due to low vibration, noise and rotational deviation. 

The methodology proved to be useful in the integrated ergonomic evaluation.

Autores: Felipe Martins de Oliveira, Eduardo da Silva Lopes, Henrique Soares Koehler e Alexandre Behling

Referência/Reference:
OLIVEIRA, F. M.; LOPES, E. S. ; KOEHLER, H. S. ; BEHLING, A. Proposition of an Integrated Ergonomic Indicator (IEI) in the assessment of forest machines. In: IUFRO World Congress Forest Research and Cooperation for Sustainable Development, 2019, Curitiba. Brazilian journal of forestry research - Special issue: Abstracts of the XXV IUFRO World Congress: Forest Research and Cooperation for Sustainable Development. Colombo: Embrapa Florestas, v. 39. p. 352, 2019.