JP-7856049-B2 - Goods handling equipment

Inventors

• 木村 康佑
• 小川 大介
• 平尾 雄也

Assignees

• 株式会社ダイフク

Dates

Publication Date

20260511

Application Date

20230519

Claims (3)

1. A transport vehicle that moves along a predetermined route to carry goods, A control device for controlling the transport vehicle, An article transporting system comprising a plurality of access points, each of which communicates wirelessly with the transport vehicle, The transport vehicle is configured to communicate with the control device by switching the access point to which it is connected while moving along the aforementioned route. When the radio signal strength between the transport vehicle and the access point falls below a predetermined switching threshold, the transport vehicle performs a switching process to switch its connection destination to another access point with a stronger signal strength. The switching threshold is set to a different value depending on the movement conditions of the transport vehicle . The aforementioned route includes at least a first area and a second area. The second area is an area where the average movement speed of the transport vehicle is higher compared to the first area. The aforementioned movement condition is that the transport vehicle moves between the first area and the second area. An article transporting system wherein the switching threshold of the transport vehicle moving in the second area is set to a higher value than the switching threshold of the transport vehicle moving in the first area .
2. A transport vehicle that moves along a predetermined route to carry goods, A control device for controlling the transport vehicle, An article transporting system comprising a plurality of access points, each of which communicates wirelessly with the transport vehicle, The transport vehicle is configured to communicate with the control device by switching the access point to which it is connected while moving along the aforementioned route. When the radio signal strength between the transport vehicle and the access point falls below a predetermined switching threshold, the transport vehicle performs a switching process to switch its connection destination to another access point with a stronger signal strength. The switching threshold is set to a different value depending on the movement conditions of the transport vehicle . The transport vehicle is further configured to perform the switching process at a predetermined set interval. The aforementioned setting cycle is changed according to the aforementioned movement conditions in the goods transport equipment.
3. The aforementioned movement condition is a change in the movement speed of the transport vehicle. The article transport equipment according to claim 1 or 2 , wherein the switching threshold is set to increase continuously or in stages as the travel speed of the transport vehicle increases.

Description

This invention relates to an article transport system comprising: a transport vehicle that moves along a predetermined route to transport articles; a control device that controls the transport vehicle; and a plurality of access points, each communicating wirelessly with the transport vehicle. For example, Japanese Patent Publication No. 2014-192577 (Patent Document 1) discloses an invention relating to wireless communication. In the following description of the background art, the reference numerals in parentheses refer to those of Patent Document 1. In the invention described in Patent Document 1, a wireless communication device mounted on a mobile terminal (2) performs wireless communication with an access point (60). This wireless communication device includes a radio wave strength detection unit (50) that detects the radio wave strength (X1) during wireless communication with the connected access point (60). It determines at predetermined time intervals whether the radio wave strength (X1) is below a roaming threshold (Xth). If it is determined that the radio wave strength (X1) is below the roaming threshold (Xth), a roaming process is performed to switch the connected access point (60). Japanese Patent Publication No. 2014-192577 Plan view of goods handling equipmentControl block diagramConceptual diagram showing the communication configurationDiagram showing an example of access point switching.A diagram showing an example of a route divided into multiple areas.This diagram shows the relationship between the average travel speed of transport vehicles set for each area and the switching threshold.Diagram showing a route divided into multiple areas in another embodiment.A diagram showing the relationship between the transport vehicle's movement speed and the switching threshold in other embodiments. The following describes an embodiment of the goods conveying equipment with reference to the drawings. As shown in Figure 1, the goods transport equipment 100 comprises a transport vehicle 1 that transports goods (not shown) along a predetermined route 8, and a control device 2 (see Figure 2, etc.) that controls the transport vehicle 1. As shown in Figure 3, in this embodiment, the path 8 is constructed using rails 80 installed near the ceiling. The transport vehicle 1 is configured as a so-called overhead transport vehicle, traveling while supported by these rails 80. In this embodiment, the transport vehicle 1 comprises a main body 10, a traveling section 11 that travels along the rails 80, and a holding section 12 for holding articles. The main body 10 is configured to accommodate the holding section 12 and the articles held in the holding section 12. As shown in Figure 1, in this embodiment, the article transport equipment 100 includes a plurality of transfer target locations 9 provided along the path 8. The transfer target locations 9 are located below the path 8. In this example, the path 8 includes an interbay and a plurality of intrabays connected to the interbay. Each intrabay is provided with a plurality of transfer target locations 9. The interbay can be described as the movement area where the transport vehicle 1 primarily moves. The intrabay can be described as the transfer area where the transport vehicle 1 primarily performs the transfer of goods. The transport vehicle 1 is configured to transfer goods between the transfer target location 9 and the transfer target location by raising and lowering the holding section 12 (see Figure 3). In this embodiment, the article transport equipment 100 is equipped with multiple transport vehicles 1. Each of the transport vehicles 1 is configured to receive a transport command from the control device 2 (see Figure 2, etc.) and to perform a task corresponding to that transport command. For example, the transport command includes information about the source and destination of the article. A transport vehicle 1 that receives a transport command transports the article from the source to the destination. The source and destination include the transfer target location 9. The goods handled by the goods handling equipment 100 can be of various types. In this example, the goods handling equipment 100 is used in a semiconductor manufacturing plant. Therefore, the goods include substrate containers (so-called FOUPs: Front Opening Unified Pods) that house substrates (wafers, panels, etc.) and reticle containers (so-called reticle pods) that house reticles. In this case, the transport vehicle 1 transports the goods, such as substrate containers and reticle containers, along the route 8 between each process. In this embodiment, the transfer target location 9 comprises a processing device 90 that performs processing on an article, and a mounting table 91 arranged adjacent to the processing device 90. In this specification, "processing on an article" means processing on the contents (substrates or reticles) contained in the article which serves as a container. The transpo