Experimental study on driver seat vibration characteristics of crawler-type combine harvester

To improve the driving comfort of combine harvesters,driver seat low-frequency vibration and related driver ride-comfort problems were investigated on a Chinese CFFL-850 crawler-type full-feed combine harvester based on ISO2631.Driver vibration and driving seat transmission characteristics were measured under the following conditions:no-load idling,driving on the road,driving in the field,and simulated harvesting.The root mean square values composite vibration under four conditions were 3.63 m/s^(2),2.35 m/s^(2),3.34 m/s^(2),and 2.67 m/s^(2),respectively.For the same condition,the maximum root mean square scores of vibration component on driver whole-body occurred in the seat support surface(test point 1)and vertical direction(Z direction),which were 3.56 m/s^(2),2.05 m/s^(2),3.15 m/s^(2),and 2.43 m/s^(2),respectively.The test point 2 to test point 1 vertical-transfer function curve trends were nearly identical.Nearly all of the transfer coefficients were greater than 1 in the range of 1-50 Hz,therefore,the seat vibration attenuation performance was poor.Based on the analysis results,the driver seat structure was altered and a verification test was performed.The test results indicated that after an X-damping mechanism was installed,vibration acceleration,on the surface of the seat support under the road-driving conditions,decreased from 2.35 m/s^(2) to 1.68 m/s^(2).Under the simulated harvesting condition,the vibration acceleration decreased from 2.56 m/s^(2) to 1.46 m/s^(2).Nearly all of the seat vertical transfer coefficients were less than 1 within the frequency range of 1-80 Hz,therefore the dynamic comfort of the seat was ameliorated after structural improvement.