Method and system for loading a driverless transport vehicle

Abstract

Driverless transport vehicles or DTVs, which are automatically guided vehicles, are gaining importance in the sorting of cargo. A method for loading a driverless transport vehicle with a cargo item in a transfer point, includes loading the DTV with the cargo item by using a known delivery system during the journey of the DTV. In order to prevent cargo items from falling during loading, a higher-level control sets the delivery speed of the cargo item and the speed of travel before the cargo item is transferred to the transport vehicle, such that the delivery speed component of the transport direction is equal to the speed of travel of the transport vehicle. In this way, the continued use of existing delivery systems such as are known under the term HSI (high speed induction) is possible. A system for loading a driverless transport vehicle is also provided.

Claims

1. A method for loading a driverless transport vehicle with a cargo item in a transfer point, the method comprising: moving the transport vehicle in a direction of transport at a speed of travel; moving the cargo item in a delivery system at a delivery speed to approach the direction of transport of the transport vehicle at a predefined acute angle; i) using a higher-level controller to set the delivery speed of the cargo item and the speed of travel of the transport vehicle before transferring the cargo item to the transport vehicle, causing a delivery speed component of the direction of transport in a region of the transfer point to be equal to the speed of travel of the transport vehicle; using the higher-level controller to cause the driverless transport vehicle to travel over a curve immediately after execution of method step i); and ii) transferring the cargo item in the transfer point from the delivery system to the transport vehicle.

2. The method according to claim 1, which further comprises transferring the cargo item into a tilt tray of an automated guided vehicle.

3. The method according to claim 2, which further comprises stopping the cargo item from sliding out by inclining the tilt tray prior to carrying out step ii).

4. The method according to claim 1, which further comprises aligning the curve to cause the driverless transport vehicle to travel in a direction of travel corresponding to a direction of induction.

5. The method according to claim 1, which further comprises providing the driverless transport vehicle with a cross-belt conveyor having a direction of conveyance orthogonal to the direction of transport of the transport vehicle, and transferring the cargo item onto the cross-belt conveyor.

6. The method according to claim 5, which further comprises carrying out step i) by using the higher-level controller to set the delivery speed of the cargo item and the speed of travel of the transport vehicle before the cargo item is transferred to the transport vehicle, and setting a delivery speed component of the cargo item in a direction of the cross-belt conveyor in the region of the transfer point to be equal to the speed of the cross-belt conveyor.

7. A system for loading a driverless transport vehicle, the system comprising: at least one delivery system delivering cargo items to a plurality of driverless transport vehicles; and a device for performing the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 illustrates a feed system with induction units and a recirculation track according to the prior art;

(2) FIG. 2 illustrates the transfer of a cargo item from the induction system to an automated guided vehicle.

DETAILED DESCRIPTION OF THE INVENTION

(3) FIG. 1 shows a feed system with induction units and a recirculation track, in accordance respectively with FIG. 2 in each of patent specifications [5] and [5′]; patent specification [5] is a translation of patent specification [5′]. Individual reference characters have been removed. Components in FIG. 2 in each of patent specifications [5] and [5′] which are also present in an embodiment of the present invention are therefore respectively provided with the same reference characters. FIG. 1 shows a carousel conveyor 25 (also called a circular conveyor), in which a dual induction unit 30A and a single induction unit 30B are provided, in order for the carousel conveyor 25 containing a plurality of carriers 50 to be loaded with cargo items 20 (not shown in FIG. 1) to be sorted. The reference character 48 designates a transfer from an induction unit 30 onto the carriers 50. Such induction units 30 also form the basis for the embodiments of the present invention.

(4) FIG. 2 shows a plan view of a transfer point 48 for the transfer of a cargo item 20 onto an automated guided vehicle AGV 10. FIG. 2 in this embodiment of the invention is based on an AGV 10 which has a cross-belt conveyor 12 driven via support rollers/drive rollers 13. The support rollers/drive rollers each have an axle 11. The illustration in FIG. 2 is a snapshot prior to the transfer of the cargo item 20 onto the AGV 10. Strictly speaking, the cargo item 20 should be shown very near the AGV 10. For reasons of clarity, it is not shown like this, but further up in FIG. 2.

(5) In another embodiment of the present invention the AGV 10 can also be provided with a tilt tray, that is to say analogously to the aforementioned tilt tray sorters.

(6) Purely by way of example, an identification/address 21 attached to a cargo item 20 is shown in FIG. 2. As in the prior art, the cargo items 20 are delivered on a delivery system to the transfer point 48 in the direction of delivery i at a speed V.sub.i. The AGV 10 approaches the transfer point 48 in the direction of transport d at a speed V.sub.d. The direction of transport d and the direction of delivery i are arranged at an acute angle β. It is assumed here that the side wall shown of the AGV 10 is parallel to the direction of transport d.

(7) The transfer point 48 is based on a control/regulation unit for the higher-level controller of the delivery system 30 and on a plurality of automated guided vehicles 10. This controller/regulation unit is not illustrated in FIG. 2 and furthermore comprises a plurality of sensors and actuators for the delivery unit, which is likewise not shown. Also not illustrated is the controller located on every AGV, which controls the route of the AGV, including the sensor system, to prevent collision. The term “transfer point” 48 here designates a functional location and not a device of the delivery system 30 or a device on the AGV 10.

(8) The aforementioned delivery speed V.sub.i, in accordance with the arrangement in FIG. 2 with the direction of travel d of the AGV, has the speed components V.sub.id in the direction of travel d, and V.sub.iCB orthogonally to the direction of travel d.

(9) For the transfer/discharge of a cargo item 20, the higher-level controller causes the speed component V.sub.id in the direction of travel d and the speed of travel V.sub.d of the automated guided vehicle AGV to be equal at the time of the transfer. As a result, a reliable and secure placement of the cargo item 20 on the AGV 10 is enabled.

(10) There remains a non-zero speed component V.sub.iCB orthogonal to the direction of travel d. For the embodiment shown of the invention in accordance with FIG. 2 a counterbalancing of said speed component V.sub.iCB takes place, in that the higher-level controller causes, by means of a corresponding sensor system at the transfer point 48, the cross-belt conveyor 12 to be driven such that its speed V.sub.CB at the time of the transfer or discharge is equal to the speed component V.sub.iCB. Immediately after the cargo item is placed, this speed V.sub.CB is reduced to zero.

(11) The angle β between the direction of travel d of the AGV and the direction of delivery i is preferably less than 45°. The speed components V.sub.id, V.sub.iCB in the direction of transport or in the direction of the moving cross-belt conveyor are given as follows:
V.sub.id=sin β.Math.V.sub.d V.sub.iCB=cos β.Math.V.sub.d

(12) Typical values for the angle β satisfy the relationship:
β≤30°.

(13) From these relationships, not only can the executability of braking by means of the cross-belt conveyor 12 be derived, but also the fact that acceleration values high enough to cause the cargo item 20 to fall off the cross-belt conveyor 12 during braking do not occur.

LIST OF REFERENCE CHARACTERS, GLOSSARY

(14) 10 Automated guided vehicle AGV 11 Axle of the roller for cross-belt conveyor 12 Cross-belt conveyor 13 Support roller/drive roller for cross-belt conveyor 20 Cargo item 21 Identification of a cargo item, e.g. address 25 Carousel conveyor, circular conveyor 26 Continuous element 28, 28′ Destination points; sorting destinations 30, 30A, 30B Induction system, induction unit 50 Carrier i Direction of induction 36 Unloading end 38 Conveyor unit of the induction system 30 48 Transfer point 50 Carrier of a continuous element 26 β Angle between direction of transport d of the transport vehicle and direction of induction i CB Direction of conveyance of the cross-belt conveyor on the AGV d Transport route, route of the automated guided vehicle AGV, direction of transport AGV Automated Guided Vehicle HSI High Speed Induction AGVS Automated Guided Vehicle System V.sub.CB Speed of the cross-belt conveyor 12 V.sub.d Speed of the automated guided vehicle AGV; speed of travel V.sub.i Speed of a cargo item on the induction system; delivery speed V.sub.id, V.sub.iCB Speed components of V.sub.i in the direction of transport or in the direction of the moving cross-belt conveyor

LIST OF CITED DOCUMENTS AND REFERENCES

(15) [1] AGV https://en.wikipedia.org/wiki/Automated guided vehicle [2] FTF https://de.wikipedia.org/wiki/Fahrerloses Transportfahrzeug [3] mobile robots https://en.wikipedia.org/wiki/Mobile robot [4] Quergurtsorter [cross-belt sorters] https://de.wikipedia.org/wiki/Quergurtsorter [5] DE 600 12 206 T2 SPEISUNGSSYSTEM MIT HOHER LEISTUNG Siemens Aktiengesellschaft German translation of patent specification [5′] [5′] EP 1 224 038 81 HIGH RATE INDUCTION SYSTEM Siemens Aktiengesellschaft