Optimising the efficiency of olive harvesting considering operator safety

Abstract

Mechanical-assisted harvesting of olives, which is carried out using hand-held harvesting units that detach the drupes through vibration supplied by electric motor or combustion engines, is a widespread method used in southern Italy. Such machines are able to harvest more than 80% of the overall quantity of olives available per tree in 5–10 min, but their performance is influenced by several factors related to the mechanical characteristics of the device and to the features of the trees. Here the problem of optimising harvesting efficiency whilst minimising the health risks to the operators is investigated, with the aim of demonstrating that it is possible to determine an optimum harvesting time which is a compromise between the harvesting efficiency and the operator safety. The quantity of harvested olives and the vibration dose received by the operator was measured simultaneously in specifically designed field tests. Vibration levels were determined by means of the SHAVE (safe hand arm vibration exposure) system, employed as a dosimeter capable of measuring the vibration level transmitted to the hand-arm system, applying the specified frequency weighting, processing the three axes of vibration data, and computing the vibration dose continuously for 8 h. By relating the time spent by the operator using the portable shaker (h), the quantity of harvested olives (kg h −1 ) and the level of exposure to vibrations (m s −2 ), an efficient management strategy for the team of operators was obtained that complied with the safety requirements for the workers involved.