Transportation system and transportation method

Abstract

In the case of transporting an article to a load port which is occupied by another article, at the time of generating a transportation command, estimated arrival time T1 when the article arrives at the load port and estimated removal time T2 when the article which occupies the load port is removed are compared with each other. If the time T2 is earlier than the time T1, a transportation command for transporting the article to the load port is assigned. If the time t2 is later than the time T1, a transportation command for transporting the article to a buffer on the upstream side of the load port is assigned.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a layout of a transportation system according to an embodiment.

FIG. 2 is a flow chart showing a prediction transportation algorithm according to the embodiment.

FIG. 3 is a flow chart showing the prediction transportation algorithm after steps in FIG. 2.

FIG. 4 is a flow chart showing the prediction transportation algorithm after steps in FIG. 3.

Claims

1. A transportation system wherein a plurality of pieces of processing equipment and a plurality of buffers are provided along a travel route for transportation vehicles, and a controller issues a transportation command for a transportation vehicle to transport an article, the transportation system comprising: prediction means for predicting whether unloading at a load port of a destination point becomes possible or not within a predetermined time from arrival of the transportation vehicle at the load port; andassignment means for assigning the transportation command to the transportation vehicle such that, if it is predicted that unloading at the load port becomes possible within the predetermined time, the article is transported to the load port as the destination point, and if it is predicted that unloading at the load port becomes possible after the predetermined time, the article is transported to a buffer as the destination point.

2. The transportation system according to claim 1, wherein the prediction means calculates estimated arrival time when the transportation vehicle loaded with the article as a first transportation vehicle arrives at the load port, and estimated removal time when a second article is transported from the load port by a second transportation vehicle, and unloading at the load port becomes possible, wherein the estimated removable time is calculated by adding a period of time required for the second transportation vehicle to arrive at the load port, and a period of time required for transferring the second article from the load port to the second transportation vehicle, to estimated time when the second article is transported from the load port; and the assignment means assigns the transportation command such that, if the estimated removal time is earlier than time after elapse of the predetermined time from the estimated arrival time, the article is transported to the load port as the destination point, and if the estimated removal time is later than the time after elapse of the predetermined time from the estimated arrival time, the article is transported to the buffer as the destination point.

3. The transportation system according to claim 2, further comprising means for changing a transportation command for the first transportation vehicle to transport the first article to a buffer on a side of the load port or a buffer on an upstream side of the load port, and changing a transportation command for the second transportation vehicle to transport the first article from the buffer to the load port, if the second article has not been transported from the load port by the second transportation vehicle when the first transportation vehicle arrives at the load port.

4. A method of transporting an article by providing a plurality of pieces of processing equipment and a plurality of buffers along a travel route of transportation vehicles, and assigning a transportation command for the article from a controller to a transportation vehicle, wherein the controller predicts whether unloading at a load port of a destination point becomes possible or not within a predetermined time from arrival of the transportation vehicle at the load port;and assigns the transportation command to the transportation vehicle such that, if the controller predicts that unloading at the load port becomes possible within the predetermined time, the article is transported to the load port as the destination point, and if the controller predicts that unloading at the load port does not become possible within the predetermined time, the article is transported to a buffer as the destination point.