Method and apparatus for assigning material transport vehicle idle locations

A method for determining parking assignments for material handling vehicles in a manufacturing system, the manufacturing system being operable to perform fabrication processes on a plurality of loads, the method comprising:

• identifying in at least one computing device at least one idle material handling vehicle;
• determining in the at least one computing device a first cost factor associated with expected transit times for the at least one idle material handling vehicle to available parking locations in the manufacturing system;
• determining in the at least one computing device a second cost factor based on a number of loads available to be serviced by the at least one idle material handling vehicle in the parking locations and relative priorities assigned to the loads;
• determining in the at least one computing device a third cost factor associated with variabilities in the expected transit times;
• employing in the at least one computing device an objective function that seeks to minimize the first and third cost factors and maximize the second cost factor to determine a parking location for the at least one idle material handling vehicle based on the first, second, and third cost factors subject to a plurality of constraints, the constraints including a first constraint that considers numbers of non-idle material transport vehicles destined for the parking locations, a second constraint defining a maximum number of material transport vehicles assignable to particular parking locations, and a third constraint defining a minimum number of material transport vehicles assignable to the particular parking locations;
• and
• issuing in the at least one computing device a parking request to the at least one idle material handling vehicle based on the determined parking location.

A system, comprising:

• a plurality of control areas for performing fabrication processes on a plurality of loads;
• a plurality of material handling vehicles for moving the loads;
• a material handling controller operable to identify at least one idle material handling vehicle, determine a first cost factor associated with expected transit times for the at least one idle material handling vehicle to available parking locations in the control areas;
• determine a second cost factor based on a number of loads available to be serviced by the at least one idle material handling vehicle in the control areas and relative priorities assigned to the loads, determine a parking location in one of the control areas for the at least one idle material handling vehicle based on the first and second cost factors, and issue a parking request to the at least one idle material handling vehicle based on the determined parking location.