Modeling of Straight-Line Driving with a Guidance Aid for a Tractor-Driving Simulator

摘要

Minor steering corrections are necessary to keep a tractor moving in a straight line. If the factors that cause such steering corrections are not considered in the implementation of a driving simulator, the task of straight-line driving will be both unrealistic and too simple. The objective of this study was to develop and validate a model, for simulation of parallel swathing in a tractor-driving simulator, which accounts for both guidance system error and tractor self-deviation. Guidance system error and tractor self-deviation were both measured by an RTK GPS system. Fourier analysis was used to determine the energy spectrum in high-, medium-, and low-frequency regions. Complex sinusoids which had similar energy distributions to those obtained from field measurements were proposed for both guidance system error and tractor self-deviation. To validate the straight-line driving model, root mean square (RMS) and frequency composition of lateral deviation of the vehicle were determined for both the tractor-driving simulator and several real systems consisting of a tractor, driver, and lightbar guidance device. Six subjects participated in the simulator study. On average, the RMS of lateral deviation was 33 cm. The energy distribution was 32% in the high-frequency region, 39% in the medium-frequency region, and 29% in the low-frequency region. Field experiments with a single driver with seven distinct lightbar guidance systems yielded an average RMS of lateral deviation of 15 cm. The energy distribution was 27% in the high-frequency region, 41% in the medium-frequency region, and 32% in the low-frequency region. Field experiments with seven drivers using a single lightbar guidance device yielded an average RMS of lateral deviation of 30 cm. The energy distribution was 30% in the high-frequency region, 40% in the medium-frequency region, and 30% in the low-frequency region. Field experiments showed close agreement with simulator experiments in terms of the frequency composition of the lateral deviations.