Effects of Rod and Oscillating Frequency on the Vibrations Transmitted to Hand-Arm System by Four Olive Portable Harvesters

This research aims to evaluate the vibration transmitted to the hand-arm system by four electric portable harvesters, mainly different for kinematics of the harvester head (synchronous or opposite), rod material (aluminum or carbon fiber), and rod configuration (fixed length or telescopic). Models with telescopic rods were tested at minimum and maximum length. All models were driven at two running frequencies: 1050 and 1200 oscillations per minute. Accelerations were measured at different times and at no-load condition in two points, 0.5 m apart, next to the hand positions. The results showed that the main difference in acceleration values was due to the kinematics of the harvester heads: 21.80 versus 6.27 m s−2 for synchronous and opposite movement, respectively. Differences between rod configurations were on average not statistical significant, as well as those between running frequencies. For each machine, acceleration values in front position (on the rod) were higher than in rear position (near the hand-grip). The differences in kinematics of the harvester head also affected acceleration component values: acceleration was higher along x-axis (19.27 m s−2) when arms carrying sticks moved synchronously and higher along y-axis (5.11 m s−2) when arms moved in opposition.