Dynamic assignment switching in the dispatching of elevator cars

Claim 1

A method for assigning hall calls registered from floors of a building to a plurality of elevator cars which provide elevator service for the floors of the building, comprising the steps of: tabulating the number of hall calls and the cumulative waiting time, calculating the average waiting time (AWT) by dividing the cumulative waiting time by the number of hall calls, storing the calculated AWT, providing a desired AWT, selecting a travel path for each car relative to a floor having a registered hall call to be assigned, preparing a trip list for each car using the travel path selected, determining the time (ETA) for each car to service the associated trip list and arrive at the floor of a hall call under consideration, assigning each new hall call to an elevator car based upon relative ETA times, reassigning a previously assigned hall call to another elevator car when said other elevator car has an ETA which is at least T seconds less than that of the previously assigned elevator car, providing an initial value for T, comparing the calculated AWT with the desired AWT, and changing T when the calculated AWT has a predetermined relationship with the desired AWT, and wherein the reassigning step uses the latest value of T.

Claim 2

A method for assigning hall calls registered from floors of a building to a plurality of elevator cars which provide elevator service for the floors of the building, comprising the steps of: tabulating the number of hall calls and the cumulative waiting time, calculating the average waiting time (AWT) by dividing the cumulative waiting time by the number of hall calls, storing the calculated AWT, providing a desired AWT, selecting a travel path for each car relative to a floor having a registered hall call to be assigned, preparing a trip list for each car using the travel path selected, determining the time (ETA) for each car to service the associated trip list and arrive at the floor of a hall call under consideration, assigning each new hall call to an elevator car based upon relative ETA times, reassigning a previously assigned hall call to another elevator car when said other elevator car has an ETA which is at least T seconds less than that of the previously assigned elevator car, providing an initial value for T, comparing the calculated AWT with the desired AWT, and changing T when the calculated AWT has a predetermined relationship with the desired AWT, and wherein the reassigning step uses the latest value of T.