Learning Curves of Harvester Operators
Frank Thomas Purfürst · University of Zagreb University Computing Centre (SRCE) · 2010
NacrtakSingle grip harvesters may reach very high productivity levels but are very expensive forestry machines.Therefore, they have to work very efficiently.This paper will analyse the learning curves of harvester operators and the influence of human factors described in a qualitative and quantitative manner.Based on long term production logging files (Stan-ForD), the performance of 32 operators was collected over a period of three years (3,351 stands, 0.65 mil.m³).16 of the operators were beginners and their learning curve was analysed and drawn as a sigmoid function.Most operators begin their career between 50% and 60% of the mean performance and double their performance (200%) by the end of the learning phase.The differences and variation in the learning curve between individual operators are large and generalisations are to be made with care.A learning curve phase productivity loss of 24% was calculated for the average 8 month duration, which equates to approximately 45000 Euro.