Horn, Joachim

Platooning and its application to meet the requirements of modern logistics has become a major field of research and gained interest in the private sector. The current state of the art is foremost concerned with homogeneous configurations. However, the research within the scope of the study "teleoperated driving in convoy applications" at the Helmut-SchmidtUniversity, Hamburg focuses on nonhomogeneous platoons. This paper seeks to motivate further research in this regard and proposes first approaches to solve arising issues. Out of the numerous variants of controllers that have been developed, a handful were selected to establish a baseline of performance in homogeneous configurations. Two testing scenarios for simulation were presented. The different controllers were compared based on their performance in the testing scenarios. Then, the composition shifted to nonhomogeneous platoons. The performance of the different systems was compared and evaluated with respect to each other and the homogeneous baseline. Observed effects are described and possible causes discussed. Various approaches to mitigate and evade negative effects were proposed and evaluated.

A control design approach for heterogeneous platoons is derived that achieves tracking of the desired delay-based spacing policy. The delay-based spacing policy induces an identical spatially varying velocity reference for all vehicles of the platoon. Thus, the control law is derived in the spatial domain. For a heterogeneous platoon, with individual dynamics of each vehicle, the first step of the control design is an individual exact linearization of each vehicle dynamics that transforms the heterogeneous platoon into a homogeneous platoon, where all vehicles have identical dynamics with respect to the new input. Then, a well-known control design for homogeneous platoons may be applied. The results are illustrated by simulations.

This paper presents a criterion and control scheme based on the assumption of a bound on the gradient of a field distribution which guarantees to find the global extremum of the distribution. Mobile robots move through the search space gathering information at points which are calculated as a minimization problem over part of the search space which is guaranteed to include the global extremum based on the previously gathered measurements. Position control in combination with collision avoidance drives each robot to the next position while communicating its position to the other robots. Upon arrival, the next measurement of the field distribution is performed and the next position reference is calculated by each robot until the robots narrowed the search area to a single location. Previously proposed control schemes can find single points as candidates for the global maximum but struggle to guarantee that this point is the global extremum. Simulation results with robot models show the performance in comparison to a naive approach.