High accuracy digital road geometry data for look-ahead transmission control of an automatic transmission

摘要

Currently, digital road maps are used in sat-nav devices. However, they are not accurate enough for transmission control. Above all, they do not provide precise information on the third dimension, altitude. Previously, compiling this kind of data was very time-consuming and expensive. Now a procedure has been developed that considerably speeds up the high-precision, 3-dimensional mapping of the center lines of roads of all classes, making seamless coverage possible. The radar image and digital elevation model products in development here provide the basis for a 3D road vector production of all classes of road in the area under consideration. An "electronic horizon" is created from this data pool that describes the constantly updated map section in front of the vehicle. This data can be applied in modern automatic transmissions. At present, gearshifts in these transmissions in automatic mode are controlled by the evaluation of current operating parameters. It is true that in most operating situations, the shift control governed by these measured parameters or parameters based on measured values produce good results, however especially in transition areas between different road gradients and degrees of driving resistance, unfavorable gearshifts often occur because conventional driving strategy does not take into account the topography of the road in front of the vehicle. This is precisely where the potential of look-ahead driving strategy comes in.