Possibilities to use automatic and manual timing in time studies on harvester operations
Nuutinen Y. (2013). Possibilities to use automatic and manual timing in time studies on harvester operations. https://doi.org/10.14214/df.156
Abstract
To date, investigations of harvester work have relied on the time study method, which is the most common work measurement technique for work studies. Time studies are often used as a basis for arriving at important conclusions or using certain technologies or working methods in harvester operations wherein the most important focus is to understand the harvester’s work process. In the era of mechanical cutting, research questions concerning harvester operations cover a wide scope. At the same time the development of time measurement techniques has provided various possibilities to obtain answers to these questions. However, despite the common consensus, the launched protocols and continuous cooperation within the forest engineering community, there is still heterogeneity in the time study approaches and techniques at the conceptual, theoretical and practical levels alike. The general objective of this thesis was to assess the suitabilities of automatic and manual time study techniques in describing the functional steps of a single-grip harvester’s work performance. The accuracy and variation of individual observers’ manual recording capabilities and the possibilities of the automatic time study method were investigated in experimental studies. To that end, actual harvester time studies using manual and automatic timing were conducted to analyze the advantages and disadvantages of both timing techniques. The results indicated that automatic time study recording is a more effective means of collecting a large amount of materials to obtain comprehensive picture of the work. The highly detailed and accurate division of work phases combined with information concerning various machine functions at the stem and log level increase the knowledge of harvester work, providing a better understanding of the structure of human-machine work. However, harvester operation may involve unforeseen situations that can confuse the automatic time study projection. There is still a need for visual and flexible observation of manual time studies when measuring a new work process. This is especially true in shorter studies with quite limited data and in fairly varying circumstances. Furthermore, automatic time studies may also be too expensive for such experiments. However, the measuring accuracy of manual timing is limited, especially in intensive time studies. In this thesis, a new process-data model of harvester operation was identified for automatic time studies. The model can also be used for the planning of manual timing. Although further research is still needed, the new work phase classification is independent of the timing techniques and its hierarchic structure enables the work phases to be dimensioned in accordance with the log level depending on the theme of research.
Keywords
single-grip harvester;
time study;
work study;
work cycle;
work phase
Published 25 February 2013
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Available at https://doi.org/10.14214/df.156 | Download PDF
Original articles
Nuutinen, Y., Väätäinen, K., Heinonen, J., Asikainen, A. & Röser, D. 2008. The accuracy of manually recorded time study data for harvester operation shown via simulator screen. Silva Fennica 42(1): 63–72.
Available at
https://doi.org/10.14214/sf.264
Nuutinen, Y., Väätäinen, K., Asikainen, A., Prinz, R. & Heinonen, J. 2010. Operational efficiency and damage to sawlogs by feed rollers of the harvester head. Silva Fennica 44(1): 121-139.
Available at
https://doi.org/10.14214/sf.165
Nuutinen, Y., Kärhä, K., Laitila, J., Jylhä, P. & Keskinen, S. 2011. Productivity of whole-tree bundler in energy wood and pulpwood harvesting from early thinnings. Scandinavian Journal of Forest Research 26: 329-338.
https://doi.org/10.1080/02827581.2011.568952
Palander, T., Nuutinen, Y., Kariniemi, A. & Väätäinen, K. 2012. Automatic time study method for recording work phase times of timber harvesting. Forest Science. Published online October 4, 2012.