Automatic lateral control of a model dozer

Control of construction machines for road building is a task already implemented in practice. In these construction machines control of the tools is realized. An automated control of position and height for the whole construction machine is only implemented for slow moving vehicles, for example asphalt or slip form pavers. This fact leaves various fields of research still open for investigations. For a complete automation on construction sites the focus will change to guidance of faster moving construction machines like graders and caterpillars in the future. The better the automated guiding of these machines works the less the demand on the controller of the tool can be defined because only small deviations have to be adjusted. To reach a good control quality, an appropriate kinematic model for the construction machine is necessary. This paper deals with tracked vehicles like caterpillars only. It will be shown how an enhancement of the control quality can be reached by using a pre-control and a calibrated steering. Therefore a steering algorithm will be presented which only needs one parameter to steer the two tracks of the caterpillar. With a hardware-in-the-loop simulator test drives on given trajectories were realized. For this purpose the automatic total station Leica TCRP 1201 as position sensor with and without pre-control was used. Under ideal conditions in the laboratory the results deliver a lateral control accuracy of 2 mm. This result is comparable to those achieved for wheeled vehicles using the single track model.