Learning Curves of Harvester Operators In A Simulator Environment

Modern tree harvesters are highly productive but increasingly complex and costly pieces of equipment. Operator training places a considerable mental burden on the trainee due to high demands on motor skills, concentration and planning. Harvester simulators assist in the initial phase of training by allowing basic skills to be acquired in a safe and relatively inexpensive manner. The aim of the study was to analyze the learning curves of the trainees in order to determine the period during which most development takes place. This would allow estimation of the optimal time required for simulator training. In this study, 11 students (10 male, 1 female) were trained on a John Deere harvester simulator for a period of approximately 15 hours (each). After every 30 minutes of training, a simple test task was performed and recorded - a total of 28 test tasks for each student. The most valuable parameters for evaluation were: productivity (calculated from task completion time), crane tip travel distance, crane control, and number of simultaneous crane movements. In each case, a clear learning curve could be identified, despite high inter- and intra-person variability. Effective time showed a steady decrease during training with a group minimum at the 27th trial (1.25 min). Crane tip distance per tree dropped rapidly in the first 6-7 trials, followed by a more gradual decrease to reach a minimum of 23.8 m in the 16th and in the final trial. Crane control - a parameter describing the precision and smoothness of crane operation - showed a significant increase from an initial 0.63 to a maximum of 0.8 (in the 17th trial), after which it fluctuated around 0.76. A number of crane functions used simultaneously increased more rapidly from an initial value of 1.5 to reach almost a maximum value (1.8) already in the 10th test (the final maximum group average of 1.82 was reached in the 20th test). The individual curves for each trainee were highly variable, showing a wide range of values and shapes. In conclusion, the simulator is a valid and effective teaching tool for the initial training period, but it must be followed by hands-on practice. Most personal development occurs during the first phase of simulator training, which typically consists of up to 17 attempts or approximately 9-10 hours. However, it is not advisable to terminate the training at this point, as some increase in performance still takes place afterwards. It is important to consider significant inter-personal variability and tailor the duration of simulator training to individual needs.