MEMS inclinometers as a method for studying harvester productivity in forestry harvesting

The study presents five arrays of harvester head inclination angles. The measurements were taken using a MEMS inclinometer during harvester operation under the control of the same operator. The recording durations ranged from 2100 to 3600 seconds. MEMS inclinometers can record both the vertical and horizontal positions of the head. The study revealed that the head was in a vertical position 28% of the time and in a horizontal position 72% of the time. The average duration of a single episode was 12 seconds with the head positioned vertically and 33 seconds with the head positioned horizontally. Statistical analysis of all data arrays revealed the average inclination angles of the head: 76.0 degrees when operating in the vertical position and –4.2 degrees in the horizontal position. The positive direction of rotation is defined as the rotation of the head from the horizontal position towards its working vertical position. Data from inclinometers enabled a detailed analysis of the technological cycle of the harvester by operation type. Each operation was characterized by its own set of statistical parameters, including standard deviation, range, and interquartile range, which describe the dispersion of inclination angle values. These parameters enabled the distinction of individual operations within the complete data array. Based on the statistical processing of all data arrays, these parameters took the following values for each operation (standard deviation / range / interquartile range, in degrees): movement of the harvester with a vertically positioned head from one working position to another: 10.8/56.9/14.3; guidance of the head at the tree: 9.3/67.9/10.7; movement of the harvester with the grabbed tree during the bucking process: 4.9/28.4/5.5; delimbing and bucking the tree: 5.9/52.4/6.6; cutting the top part of the tree and collecting the branches onto the forwarding trail: 13.2/108.0/15.2; and movement of the harvester from one working position to another with a horizontally positioned head: 14.4/78.7/20.4. The average shares of these operations in the total structure of the technological cycle were as follows: 3.5%; 14.5%; 4.9%; 35.2%; 14.6%, and 5.6%, respectively. In addition: bringing the head to vertical –3.5%; tree felling –12.8%; other operations –3.0%; pauses –3.0%. The angle values, presented in the form of continuous data arrays, provide new data for the analysis of logging mechanics.