Prediction of the vibration characteristics of half-track tractor considering a three-dimensional dynamic model

A dynamic three-dimensional model was constructed for a half-track tractor that considers its bounce, pitch, and roll motions in order to clarify the tractor's vibration characteristics. Driving experiments were conducted in which the tractor was driven on a solid asphalt road surface in order to investigate its vibration characteristics and to verify the validity of an analysis based on motion equations that were formulated from the proposed dynamic model. The experiments were conducted with a half-track tractor apparatus equipped with twelve accelerometers for the measurement of 6 DOF of acceleration of the tractor's centre of gravity. The discrete time series of the measured data was resolved and reconstructed by wavelet analysis. The model was verified using the fixed lug phase difference between the left and the right crawler systems for each combination of three location arrangements of the track rollers and seven levels of tractor speed. Results showed that the acceleration of the centre of gravity for the bounce, pitch, and roll motions was at a minimum when the track rollers were set equidistant from one another. The acceleration caused by the bounce and pitch motions decreased with an increase in the lug phase difference, while the acceleration caused by the roll motion increased with an increase in the lug phase difference. The results further suggested that the proposed three-dimensional dynamic model could be improved by incorporating into it the lug phase differences that change during actual tractor driving, instead of a constant lug phase difference.