METHOD FOR OPERATING A TRANSPORT SYSTEM AND TRANSPORT SYSTEM

Abstract

A method serves to operate a transport system, in particular a multi-carrier system, that comprises a plurality of linear motors that are arranged in a row and have a guide track, a plurality of transport elements that can be moved along the guide track by means of the linear motors, and a plurality of stations along the guide track, wherein each of the transport elements is associated with one of the stations. The method has the following steps: generating an instance for each of the transport elements, generating a list for each of the stations, wherein the instance for each of the transport elements associated with the respective station is associated with the list, and wherein, within the respective list, the instance of each transport element is linked to the instance of the transport element directly ahead of the observed transport element and to the instance of the transport element directly behind the observed transport element, transferring a transport element from a first station to a directly following second station and inserting the instance of this transport element into the list of the second station if a transport job that goes beyond the first station is present for the transport element, wherein the transfer of the instance takes place in an event-controlled manner and independently of a transfer point if a predetermined transfer condition is fulfilled, and controlling the linear motors to execute travel jobs of the transport elements.

Claims

1. A method for operating a transport system, comprising: a plurality of linear motors that are arranged in a row and have a guide track, a plurality of transport elements that can be moved along the guide track by means of the linear motors, and a plurality of stations along the guide track, wherein each of the transport elements is associated with one of the stations, and wherein the method comprises: generating an instance for each of the transport elements, generating a list for each of the stations wherein the instance for each of the transport elements associated with the respective station is associated with the list, and wherein, within the respective list, the instance of each transport element is linked to the instance of the transport element directly ahead of the observed transport element and to the instance of the transport element directly behind the observed transport element, transferring a transport element from a first station to a directly following second station and inserting the instance of this transport element into the list of the second station if a transport job that goes beyond the first station is present for the transport element, wherein the transfer takes place in an event-controlled manner and independently of a transfer point if a predetermined transfer condition is fulfilled, and controlling the linear motors to execute travel jobs of the transport elements.

2. The method in accordance with claim 1, wherein the transfer condition is fulfilled when the transport element has set off and/or has reached a predetermined transfer speed.

3. The method in accordance with claim 1, wherein each instance has the link to the instance of the transport element directly in front of the observed transport element, the link to the instance of the transport element directly behind the observed transport element, and an identification feature for the respective transport element.

4. The method in accordance with claim 3, wherein the links are each configured as pointers referring to memory addresses of the respective instance.

5. The method in accordance with claim 4, wherein the transfer of an instance from the first station to the directly following second station takes place by overwriting the memory addresses to which the respective pointers refer.

6. The method in accordance with claim 1, wherein the transport system has a control unit and a memory area for creating instances for each of the transport elements is provided in the control unit.

7. The method in accordance with claim 1, wherein the stations are at least partly arranged at identical positions along the guide track.

8. A transport system that comprises a plurality of linear motors that are arranged in a row and have a guide track, a plurality of transport elements that can be moved along the guide track by means of the linear motors, and a plurality of stations along the guide track, and further comprising a control unit that is configured to carry out the method in accordance with claim 1.

9. The transport system in accordance with claim 8, wherein the stations are at least partly arranged at identical positions along the guide track.

10. The method in accordance with claim 1, wherein the transport system is a multi-carrier system

11. The transport system in accordance with claim 8 that is a multi-carrier system.

Description

[0033] The invention will be described schematically and by way of example with reference to the drawings. It is shown therein:

[0034] FIG. 1 a plan view of a transport system configured as a multi-carrier system in accordance with an embodiment;

[0035] FIG. 2 an example of a list of a station with which three transport elements are associated;

[0036] FIG. 3 the list from FIG. 2 after the first instance in the list has been transferred to a following station; and

[0037] FIG. 4 the list of the following station after the first instance of the list from FIG. 2 has been transferred to it.

[0038] FIG. 1 schematically shows, in a plan view, a transport system 10 that is configured as a multi-carrier system and that has a plurality of linear motors 11 that in the present embodiment are arranged in a row closed in itself and form a closed guide track 13 for transport elements 15, 17, 19. For an illustrative description, only three transport elements 15, 17, 19 are shown in FIG. 1, namely a first transport element 15, a second transport element 17, which is located directly before the first transport element 15 in the direction of movement x, and a third transport element 19 that is located directly behind the first transport element 15 in the direction of movement x. Directly is in this respect not to be understood as referring to a specific distance between the respective transport elements 15, 17, 19, but rather means that there is no further transport element between directly consecutive transport elements 15, 17, 19.

[0039] The transport elements 15, 17, 19 are magnetically driven by the linear motors 11. For this purpose, the transport elements 15, 17, 19 have one or more permanent magnets, not shown, that are acted on by a driving force by means of a changing and/or wandering magnetic field that is generated by the linear motors 11. The driving force leads to a movement of the transport elements 15, 17, 19 along the guide track 13. The transport elements 15, 17, 19 can in particular be moved independently and separately from one another. The linear motors 11 are controlled by a control unit, not shown, to drive the respective transport elements 15, 17, 19.

[0040] As can be seen from FIG. 1, a plurality of stations S.sub.1, S.sub.2, S.sub.3 are arranged along the guide track 13 and can, for example, be defined by their position in the direction of movement x along the guide track 13. At the stations, transport elements 15, 17, 19 can, for example, be combined or separated again or can pick up a product for transport or deliver it again. For example, the transport elements 15, 17, 19 can receive an instruction from the control unit that allows the respective transport element to move from station S.sub.1 to station S.sub.2. Such instructions are also designated as a travel job. In FIG. 1, each of the stations S.sub.1, S.sub.2, S.sub.3 is arranged at a separate position or coordinate along the guide track 13. In principle, it can alternatively also be implemented that the stations S.sub.1, S.sub.2, S.sub.3 that are purely virtually defined by their position or coordinate along the guide track 13 in the present embodiment are completely or partly arranged at identical positions or coordinates that can then perform different functions, for example.

[0041] Each of the transport elements 15, 17, 19 on the path is associated with exactly one of the stations S.sub.1, S.sub.2, S.sub.3 at any point in time. This means that the respective station S.sub.1, S.sub.2, S.sub.3 is responsible for the transport elements 15, 17, 19 associated with it and can execute commands for the transport elements 15, 17, 19, in particular for stopping or driving, by means of the control unit.

[0042] FIG. 2 shows an example of an association in accordance with the invention of three transport elements with one station, wherein FIG. 2 is to be understood as a purely schematic reproduction of a data structure used as an example.

[0043] In accordance with the invention, an instance is created for each transport element (also referred to as a carrier, a mover, or a runner) that is located on the path. If, for example, twenty transport elements are moved on the path, twenty instances are created so that there is a corresponding pool with one instance for each transport element. This in particular takes place in a central memory area of the control unit that is provided centrally for the maximum number of transport elements. FIG. 2 shows, by way of example, a list L.sub.S1 of a station (referred to as Station 1). The list L.sub.S1 can also be called a chain and includes three instances I.sub.1, I.sub.2, I.sub.3 that are each associated with a transport element.

[0044] Each of the instances I.sub.1, I.sub.2, I.sub.3 is provided with an identification feature 21 that uniquely identifies the transport element corresponding to the respective instance I.sub.1, I.sub.2, I.sub.3 (Carrier 1, Carrier 10, Carrier 9). Furthermore, each instance I.sub.1, I.sub.2, I.sub.3 has a link 23 to the instance of the transport element directly ahead of the observed transport element and a link 25 to the instance of the transport element directly behind the observed transport element. The links 23, 25 are in particular configured as pointers that refer to the memory areas of the respective target elements. If it is the foremost transport element in the direction of movement x or the last transport element in the direction of movement x that is associated with the corresponding station, the respective links 23, 25 are marked as links to nothing, namely here as a null reference, see the link 23 of the instance I.sub.1 and the link 25 of the instance I.sub.3.

[0045] With this data structure, an overview results for the station at any point in time, on the basis of its list, of all the transport elements associated with the station, their logical sequence along the direction of movement x and, based on the null references, also an overview of which transport element is the first or the last transport element along the direction of movement x that is associated with the station. Significant memory savings can be achieved in this respect since sufficient memory for the maximum number of transport elements does not have to be provided for each station. Rather, a global pool of instances, which are each associated with a list or chain, is created. Furthermore, an additional management of the sequence of the transport elements associated with the station along the path is obsolete. The station that will always grant the next travel job to the first element of the list or chain that is linked to this foremost transport element can always address the corresponding transport element via the first entry of its list.

[0046] FIGS. 3 and 4 illustrate the transfer of a transport element from one station (Station 1 in accordance with FIG. 3) to the station directly following it in the direction of movement x (Station 2 in accordance with FIG. 4). FIG. 3 substantially corresponds to FIG. 2, wherein the instance I.sub.1 shown in FIG. 2, corresponding to the foremost transport element in the direction of movement x that is assigned to the station, has already been transferred to the next station and has therefore been removed from the list L.sub.S1. The link 23 of the instance I.sub.2 has been changed accordingly to a null reference so that it can be seen that Carrier 10 is the foremost transport element in the direction of movement x that is currently associated with Station 1.

[0047] In accordance with FIG. 4, the list L.sub.S2 of the station directly following in the direction of movement x (Station 2) includes the instance I.sub.1, which was previously associated with Station 1, as the only entry after the transfer. That is, Station 2 is assigned exclusively to Carrier 1. Accordingly, both links 23, 25 are provided with a null reference.

[0048] In an implementation with pointers as links 23, 25, the transfer of the respective instances can therefore already be effected by overwriting the memory addresses to which the respective pointers refer in each case so that the transferred instance is correctly removed from the list or chain link of the preceding station and is added to the list or chain link of the following station.

[0049] The transfer takes place in an event-controlled manner without separate transfer points being required that are also designated as trigger points. Only a defined transfer condition is required. This can be, for example, that the transport element has been set into motion or has reached a certain transfer speed. Thus, it is, for example, possible for the transport element to be transferred to the following station directly after starting to move, even if it has not yet arrived there. A stopping at a waiting position or transfer position is then not necessary if the receiving station is free. If the currently executed transport job goes beyond the receiving station and the receiving station is free, the latter can even directly transfer the transport element further to the next following station. The travel time can thus already be used to prepare commands for the transport element. Ideally, unnecessary stopping processes for the respective transport element can be avoided.

[0050] The method described here thus leads, on the one hand, to memory savings and, on the other hand, also to an improved and simplified handling of transport elements on the path.

REFERENCE NUMERAL LIST

[0051] 10 transport system [0052] 11 linear motor [0053] 13 guide track [0054] 15 first transport element [0055] 17 second transport element [0056] 19 third transport element [0057] 21 identification feature [0058] 23 link [0059] 25 link [0060] I.sub.1 instance [0061] I.sub.2 instance [0062] I.sub.3 instance [0063] L.sub.S1 list (station 1) [0064] L.sub.S2 list (station 2) [0065] S.sub.1 station [0066] S.sub.2 station [0067] S.sub.3 station [0068] x direction of movement