Path tracking driver models assume the observed path deviation ahead of the vehicle to be proportionally transferred to a corrective steering input. The most simple version of such a model includes three parameters, a single preview distance, a steering gain and a delay time, being examined in this paper, in dependency of vehicle properties, driver characteristics, velocity and path. It is shown that, for different and bounded preview lengths, a driver can follow any path with almost the same minimum path error, if the gain is adapted appropriately. The upper boundary is path-dependent but driver and path characteristics have only a minor effect on the resulting relationship between preview length and gain. Consequently, gain and preview length may well vary along some path. This has been examined, experimentally, for different drivers. A too small preview length conflicts with closed-loop stability, explicitly described in terms of vehicle parameters, vehicle speed and driver delay time. The results of this paper provide a basis for enhanced understanding of human driver behaviour. (Author/publisher)
Abstract