Implementation of robot routing approaches for convoy merging manoeuvres

Autonomous and cooperative guidance strategies for a convoy of electric vehicles in an urban context are challenging research topics in robotics and intelligent transportation systems. The vehicles that form the convoy eventually will have to leave it to perform a mission and return to the convoy formation once the mission has been accomplished. Nevertheless, the merging manoeuvres amongst the convoy and the units returning to it (pursuing units) is a complex task that involves the determination of the best merging point and the route across the city to reach it. This paper tackles this routing problem of a robot located in a map that is trying to join a convoy of robots in constant movement along a peripheral trajectory. We have developed two search strategies able to determine the optimal merging point and the best route to reach it: on one hand we describe a basic solution able to solve the problem when the time spent by the robot traveling along every street of the map is considered to be known and constant. On the other hand, we extended this basic approach to provide a new search strategy that considers uncertainty in traveling times. This increases considerably the complexity of the problem and makes necessary the inclusion of a risk factor that must be considered when determining the best route and the merging point for the manoeuvre. We also put our search strategies into practice in both, simulated and real scenarios. On one hand we have simulated the behavior of a convoy leader and a transport unit which is trying to join in the convoy, using Player&Stage. On the other hand we have used real P3-DX robot units as prototypes of electrical vehicles in a transport scenario.

keywords: Dynamic route planner, Optimal meeting point, Merging convoy manoeuvre, Dynamic programming, Uncertain traveling time