Evaluation of the Control Quality for Tachymetric Controlled Vehicles

This contribution presents the application of a new method for the evaluation of the control quality for vehicles, controlled by robot tachymeters. The method shows in which way a highly accurate measurement system, consisting of a laser tracker and an active target, is used to separate the measurement accuracy from the control quality for a subsequent evaluation. For several years, the Institute of Engineering Geodesy, University of Stuttgart operates a construction machine simulator to evaluate the performance of different sensors as well as filter and control algorithms under laboratory conditions. For this purpose a model truck (scale 1:14) is guided on a predefined reference trajectory as accurately as possible. Thereby the lateral control is realized by a PID controller. The root mean square value (RMS) of the lateral deviation between the driven and reference trajectory is called combined measure and is defined as quality criterion. Under laboratory conditions, the simulator achieves RMS values for combined measures of 2-4 mm. These values contain the measurement accuracy and the control quality. An external measurement system, the API Radian laser tracker, in combination with an active target allows to split up the two quantities. Thus the control quality can be evaluated individually. The investigation has shown that the simulator system reaches a control quality of 3,1 mm and a measurement accuracy of 2,9 mm.