Simulation And Testing Research On Vibration Characteristics Of Tractor Driver–Chair System

With the rapid development of China’s agricultural economy, more and more demand for tractors. In the process of tractor driving, especially during the period of agricultural products transportation, due to the poor road conditions and tractor’s poor damping effect, so the tractor driver body often suffer severe low frequency and high strength vibration, hurt the driver’s physical and mental health. So investigate the tractor driver-chair system vibration characteristics under the road excitation is of great significance. However research focuses in the car at home and abroad, lack of the study of tractor driver-chair system vibration characteristics, especially lack research of the vibration characteristics of driver’s different body segments. In order to study the vibration characteristics of tractor driver during driving, the paper uses MATLAB / Simulink simulation software, set up six degrees of freedom of the tractor driver-chair system vibration model, with a type of the tractor as an example, simulated and analyzed tractor driver each body segment’s vibration characteristics under different road and different speed. At the meanwhile,carried out the real vehicle verification test under the dirt road and the asphalt road.Through contrast and analysis the simulation and test results of time domain and frequency domain, obtained the following conclusion :The error range of simulation results and test results is between 2% to 18%, wherein the head of the driver error> driver’s seat and leg error> driver’s upper and lower torso error. Error is within the allowable range, indicating that the simulation model has high reliability, it can make a good simulation prediction of the tractor driver each body segment’s vibration characteristics under the road stimulate during the process of tractor driving.Driver’s different body segments and seat vibration under weighted acceleration from big to small in order is: tractor seat> driver’s upper and lower torso vibration> driver’s leg vibration>driver’s head vibration. Vibration acceleration of tractor driver different body segments and seat increases with the rise of the speed, increases with the decreasing of road level.The peak frequency of different body segments and the tractor driver seat mainly between1~4Hz, mostly concentrated in the vicinity of 3Hz. Where the driver’s head vibration frequency domain mainly between 0~5Hz, driver’s upper and lower torso vibration frequency domain mainly between 1~6Hz, the driver’s legs and seat vibration frequency domain mainly concentrated in the1~9Hz. Distribution of vibration frequency domain in a tractor seat to drivers in the process of transfer from bottom to top of the head and its frequency distribution domain is more and more narrow, the driver of low frequency vibration components increase gradually. At the same time,the simulation and experimental results of frequency domain analysis is consistent.Acceleration power spectral density of simulation and experimental results shows that with the increase of vehicle speed, lower road level, the frequency of extreme value corresponding to the peak of the driver’s different body segments and seat also will be increased, meet the incentives- response law.Based on the tractor driver’s body feeling to the vibration frequency domain, combined with the body’s response to different excitation frequencies shows that the driver’s head will have little affects to vibration; road incentives for driver’s upper and lower torso vibrations would be likely to affect the comfort of driver’s chest and abdomen, cervical vertebra and lumbar etc; driver’s leg vibration may cause the leg muscle tension; and part of the tractor seat vibration peak frequency beyond the tractor seat best vibration frequency range.The conclusion of this paper can serve for the prediction of tractor driver’s vibration situation, and provide the theory basis of the vibration differences of tractor driver’s different body segments.