Planning Movements for Several Coordinated Vehicles

This paper describes a two-level controlling system for a set of non-holonomic vehicles moving in a dynamic universei.e. among static and moving objects-. The higher level is concerned with planning a trajectory for each vehicle whereas the execution of the plan is distributed at the level of each vehicle. This paper focuses on the higher level i.e. the global planner. Our approach consists in first assigning priorities to the vehicles and then in planning motions one vehicle at a time. For that purpose, we make use of a path/velocity decomposition and of techniques to deal with the kinematic constraints of the vehicles. Planning the velocity parameters is then achieved by temporally allocatiiig “conflict regions” to the vehicles. In order to deal with the uncertainty introduced by the changes of the universe, tlic globill p1;iniicr operatos periodidly on a given interval of time.