Ride Comfort of Agricultural Tractors - Objective Measurements and Subjective Evaluation

摘要

Whole-body vibration of agricultural tractor operators has a great influence on the perception of ride comfort. While measurements of acceleration levels deliver an objective representation of vibration intensities expressed in numerical values ride comfort may be described also through subjective perception of the operator itself. Four different test types with an agricultural tractor operated by a group of seven test persons with varying features were carried out in order to examine interrelations between objective measurements and subjective evaluation of ride comfort. Two test types included the excitation of the vehicle with a mounted shaker device to determine the perception threshold of the test persons. Two other test types comprised test rides at different vehicle ground speeds without excitation of the shaker device. Signals of accelerometers mounted to the tractor were analyzed in the time and frequency domain using frequency weighting functions. Subjective evaluation of ride comfort was documented using appropriate questionnaires. The acceleration data, subjective evaluation as well as the vehicle driving speed served as inputs for a correlation analysis routine. There were found a number of high correlations between the frequency weighted acceleration signals and the associated subjective evaluation though the correlation quality varied within the group of test persons. It can be concluded that also non professional test drivers are capable to evaluate different types of vehicle vibration.