Mohammad Hejazian, Seyedataollah Hosseini, Majid Lotfalian and Parisa Ahmadikoolaei
Time study is one of the techniques which are used to evaluate the performance of forest machinery. This study is time consuming and expenses. According to appearance of new technologies in recent years, it is possible to use this method in time study. It is necessary to investigate the accuracy and efficiency of the results of this method in scientific researches. GPS is based on geographical information system which can record local and time data. This system has a high accuracy to record all movements of machine in forest. In this study the possibility of the application of trip recorder was assessed for time studies forest machinery. The studied skidding machine was wheeled skidder Timber jack 450c.31 skidding cycle recorded. Results indicated that 29 cycles of 31 skidding cycle was determined and assessed by GPS. The time study with GPS was along with 7% error and 93% confidence. The mean of skidding time in each cycle was 968.79 seconds for stop watch (traditional method) and 959.21 seconds for GPS. The error was 0.01%. In investigation of the components of skidding cycle, there were most variations in skidding distances. The distances in GPS method was 11% less than that of traditional method. In stop watch method 15 minutes per cycle was spend for measuring of skidding distance. This additional time was removed in GPS method. Results show that with using GPS the time and cost of time study can be reduced.
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