Measurement and Analysis of Body Vibrations of an Articulated Orchard Tractor Operator in Time and Frequency Domain

The agricultural machinery vibration to the driver's body causes discomfort, injury and pain and reduces work efficiency. Articulated Orchard Tractors is widely used as a power source in small and medium farms for agricultural and horticultural operations. The transmitted vibration signals of a Articulated Orchard Tractor to the different body parts of the driver, ankle, wrist, seat, chest and head, were investigated and recorded based on ISO ۵۳۴۹ and ISO ۲۶۳۱ standards in three directions: vertical, longitudinal, and lateral. The effects of gear ratio (۱, ۳ and ۶), engine rotational speed (۱۵۰۰ and ۲۵۰۰ rpm), load mode (loaded and unload) and road condition (asphalt and farm) were examined on the vibrations. The signals were converted to the frequency domain using the FFT Algorithm and ۱/۳ octave band of vibration spectrum was obtained. The peak of vibration accelerations were observed at ۲۰.۷ and ۴۱.۵ Hz frequencies which are related to the engine rotational speed and maximum piston acceleration. Comparison of the vibration acceleration in different body parts showed that the ankles and wrists had the highest and head and chest had the least amounts. Studying the comfort limits revealed that the vibration between ۱۰ to ۸۰ Hz had a range of ۰.۳۳ to ۰.۴۳ m.s-۲, which was in the alittle uncomfortable range. It was also found that the vibration acceleration values in the vertical direction exceeded the allowable working time. The acceleration of the vibration in the longitudinal and lateral directions had not exceeded the allowable working time.

کلیدواژه ها:

Acceleration ، Convenience ، Exposure time ، ۱/۳ octave band