Hierarchical control system for automatically guided vehicles

The invention is a modular and hierarchically organized set of computer programs which comprise methods for controlling a system of semi-autonomous automatically guided vehicles, such as mobile robots. The methods include control programs which: execute in stationary control computers; communicate between the stationary control computer programs and corresponding programs which execute in mobile control computers aboard the vehicles; operate independently in mobile control computers aboard the vehicles. The invention allows the system executive program to command the mobile vehicles to start, to stop, to transfer material to or from the vehicles, to change batteries in the vehicles, to park the vehicles at specific points in a factory, to move the vehicles from point to point in a factory, and to remove the vehicles from the factory. The invention proves the performance of conventional automatically guided vehicle systems by maximizing the autonomy of individual vehicles while retaining sufficient supervisory control at the system executive level to provide the maximum flexibility in routing and scheduling the activity of the vehicles. The invention "closes the loop" in an automatically guided vehicle system by providing the highest level of control between mobile vehicles and stationary control computers.