Elevator system configured to decentralize allocation of hall calls

Abstract

A method for allocating elevators in an elevator system, the elevator system including a group control system responsive to hall calls received from call input devices, and elevator-specific elevator controllers configured to control elevators based on commands issued by the group control system, wherein the method including generating a number of route alternatives based on calls active; calculating, by the elevator controllers, elevator-specific cost terms associated with the route alternatives; transmitting, by the elevator controllers, the cost terms to the group control system; and allocating, by the group control system, the hall calls to the elevators according to the route alternative giving the lowest allocation cost.

Claims

1. A method for allocating elevators by at least one group control system in an elevator system, the elevator system including the at least one group control system and elevator-specific elevator controllers configured to control elevators based on commands issued by the at least one group control system, wherein the method comprises: registering hall calls entered using the call input devices; generating a number of route alternatives based on active ones of the hall calls; receiving elevator specific cost terms from the elevator controllers, the elevator-specific cost terms being associated with the route alternatives; and allocating the hall calls to the elevators according to the route alternative giving the lowest allocation cost by, determining which ones of the hall calls are traditional calls received from an up/down input device and which ones of the hall calls are destination calls received from a destination call terminal, allocating the destination calls based on the route alternative giving the lowest allocation cost without delaying the allocating of the destination calls, and delaying allocating the traditional calls by instructing the elevator controllers to recalculate the cost terms associated with the traditional calls as the elevator giving the lowest allocation cost approaches a call input floor associated with the up/down input device.

2. The method according to claim 1, wherein the method further comprises: instructing the elevator controllers to recalculate the cost terms at desired intervals; and deciding which one of the elevators is to serve a respective one of the hall calls after input of the call before arrival of the elevator to be allocated at the call input floor.

3. The method according to claim 1, wherein the method further comprises: allocating one of the elevators to serve a hall call in connection with call input such that the one of the elevators allocated to the passenger and its location are immediately indicated through a guidance device provided in conjunction with the call input device.

4. The method according to claim 1, wherein the at least one group control system includes a plurality of group control systems, and the method further comprises: interconnecting the plurality of group control systems of different elevator groups via a data transfer connection; transmitting the call data from a first group control system of the plurality of group control systems having received a call to a second group control system of the plurality of group control systems, the first group control system associated with a first elevator group and the second group control system associated with a second elevator group; receiving from the second group control system the elevator-specific cost terms calculated for the elevators of the second elevator group; and taking the said cost terms into account to allocate an elevator to serve the passenger from any one of the first elevator group the second elevator group.

5. The method according to claim 4, wherein the transmission of call data to the plurality of group control systems is activated dynamically based on a desired service criterion.

6. The method according to claim 1, wherein the number of cost terms used in allocation is selected dynamically based on a desired service criterion.

7. An elevator system, comprising a number of elevators; call input devices each associated with different floors, the call input devices configured to receive hall calls; and elevator-specific elevator controllers configured to control the elevators based on commands; and at least one group control system configured to, register hall calls entered using the call input devices, generate a number of route alternatives based on active ones of the hall calls, transmit to the elevator controllers elevator-specific route data corresponding to the route alternatives, receive, from the elevator controllers, elevator-specific cost terms associated with the routes, and allocate the hall calls to the elevators according to the route alternative giving the lowest allocation cost.

8. The elevator system according to claim 7, wherein the group control system is configured to, repeat allocation calculation at desired intervals, and to decide on the elevator to be allocated after call input before arrival of the elevator to be allocated at the call input floor.

9. The elevator system according to claim 7, further comprising: a guidance device configured to guide the passenger to the allocated elevator and/or elevator group.

10. The elevator system according to claim 7, wherein the at least one group control system includes a plurality of group control systems interconnected by a data transfer bus, the plurality of group control systems associated with different elevator groups, and a first group control system of the plurality of group control systems is configured to, transmit call data to a second group control system of the plurality of group control systems, the first group control system associated with a first elevator group and the second group control system associated with a second elevator group, receive from the second group control system the elevator-specific cost terms calculated for the elevators of the second elevator group, and allocate elevators from any one of the first elevator group and the second elevator group based on said cost terms.

11. The elevator system according to claim 10, wherein the first group control system is configured to, activate the transmission of call data to the second group control system dynamically based on a given service criterion.

12. The elevator system according to claim 7, wherein the at least one group control system is configured to select the number of cost terms dynamically based on a desired service criterion.

13. The method according to claim 6, wherein the method further comprises: varying, by the group control system, the number of cost terms based on one or more of a time of day and elevator traffic.

14. The elevator system according to claim 12, wherein the at least one group control system is configured to vary the number of cost terms based on one or more of a time of day and elevator traffic.

Description

LIST OF FIGURES

(1) In the following, the invention will be described in detail by referring to embodiment examples, wherein

(2) FIG. 1 represents an elevator system according to the invention;

(3) FIG. 2 represents a second elevator system according to the invention; and

(4) FIG. 3 illustrates the distribution of allocation calculation between elevator controllers and the making of a final allocation decision in the group control system.

BRIEF DESCRIPTION OF THE INVENTION

(5) FIG. 1 represents an elevator group which comprises four elevators A, B, C and D. The elevators in the elevator group serve building floors F0-F10. Installed at the floors are destination call terminals 110, which are connected over a device bus 103 to the group control system 101. Instead of destination call terminals, the call input devices used may also be traditional up/down buttons (not shown in FIG. 1). The number and disposition of the call input devices at the floors can be selected separately in each case; for example, an extra destination call terminal may be placed in the entrance lobby near the entrance door, thus allowing the passenger to give a destination call in good time before arriving at the elevators. Each elevator is controlled by an elevator controller 120 based on commands sent by the group control system 101.

(6) When a passenger gives a destination call through a destination call terminal 110, the group control system registers the passenger's departure floor (the floor at which the call was input) and destination floor (the floor to which the passenger is going). The group control system generates from active calls a number of route alternatives and transmits corresponding elevator-specific route data to the relevant elevator controllers 120. The elevator controllers calculate the cost terms associated with the elevator-specific routes on the basis of the route data and elevator status data and return the cost terms to the group control system 101. Based on the cost terms, the group control system calculates the total cost of each route alternative and allocates the calls to the elevators according to the route alternative giving the lowest total cost. Elevator status data include e.g. the floor at which the elevator is currently located, number of passengers in the elevator car, calls to be served by the elevator, traveling direction. Moreover, the elevator controllers have information regarding the door times of the elevator to be controlled, the running times between floors, and other parameters needed for the calculation of cost terms. Cost term refers e.g. to the waiting time, travel time, energy consumption or other corresponding cost incurred if the calls included in the route alternative were to be served by the elevator in question.

(7) According to an embodiment of the invention, each elevator controller 120 always calculates a predetermined number of cost terms, of which only those cost terms which are needed in allocation calculation are used by the group control system. The number and weighting of the cost terms used in the cost function can be dynamically changed by the group control system e.g. based on the time of the day or the traffic situation prevailing in the elevator group.

(8) Utilizing the cost terms, the group control system 101 thus calculates the allocation costs associated with the route alternatives and allocates the calls to the elevators in such a way that the allocation cost is minimized. The allocation costs can be calculated by applying allocation methods known in themselves, in which methods one or more aforesaid elevator-specific cost terms are taken into account.

(9) If the hall call registered is a destination call, then an elevator is allocated immediately. The passenger having entered the call is informed by visual or auditory means about the elevator and, if necessary, its current location via guidance means 112 provided in conjunction with the destination call terminal. If the hall call registered is a call entered using up/down buttons, then the group control system will keep repeating the above-described allocation calculation e.g. at 0.3 second intervals until the desired termination criterion is met and the group control system makes a decision regarding the elevator (assigns an elevator) to serve the call. The above-mentioned calculation time is only given by way of example and may be longer or shorter than this, depending on the application. The aforesaid termination criterion is e.g. that the time remaining for the elevator consistent with the allocation result to reach the deceleration point corresponding to the call input floor is sufficiently short.

(10) FIG. 2 presents by way of example another elevator system according to the invention, comprising two elevator groups X and Y. Elevator group X comprises elevators A and B, which are controlled by elevator controllers 120 on the basis of commands sent by group control system 101. Elevator group Y comprises elevators C and D, which are controlled by elevator controllers 220 on the basis of commands sent by group control system 201. All the elevators can serve building floors F0-F10. Mounted at the floor landings are destination call terminals 110 and 210, and of these, destination call terminals 110 are connected over device bus 103 to group control system 101 while destination call terminals 210 are connected over device bus 203 to group control system 201. The group control systems 101 and 201 are interconnected via a data transfer bus 205 applicable for transmitting data between the group control systems.

(11) If a passenger gives a destination call e.g. from the entrance lobby using destination call terminal 110, the group control system 101 of elevator group X will register the destination call and transmit the call data to group control system 201. Elevator controllers 120 calculate elevator-specific cost terms and return them to group control system 101 as explained above. Elevator controllers 220 calculate corresponding cost terms and send them to group control system 201, which transmits them further to group control system 101 via data transfer bus 205. When group control system 101 has the cost terms for all the elevators A, B, C and D, it allocates the best elevator from either elevator group on the basis of the cost terms. The passenger is informed via the guiding means 112 of the destination call terminal 110 about the elevator and/or elevator group allocated. Similarly, if a passenger gives a destination call using a destination call terminal 210 of elevator group Y, a decision regarding the elevator to be allocated will be made by group control system 201 in a corresponding manner, as described in the above example.

(12) In the elevator system illustrated in FIG. 2, the decision to transmit the call data from one group control system to the other may be based on a desired service criterion. For example, if in elevator group X the average waiting time exceeds a given threshold value, then group control system 101 will activate transmission of call data to group control system 201 to equalize the transport capacity between the elevator groups X and Y. In quiet traffic conditions, each elevator group can work independently, in which case it is e.g. easier for the passenger to get to the elevator serving him/her. As explained above, in the destination floor control system, each call is allocated only once and assigned immediately to that elevator which optimizes the allocation cost calculated by the cost function.

(13) FIG. 3 illustrates by way of example the distribution of allocation calculation between elevator controllers 303 (elevator controllers 1-12) and the making of a final allocation decision in the group control system 304. Reference number 302 denotes elevator-specific route data, which are generated on the basis of the calls active and sent to the elevator controllers 303 by the group control system. The elevator controllers calculate the elevator-specific cost terms associated with the routes and return them to the group control system (indicated by reference number 301 in FIG. 3). The group control system calculates the allocation costs of the route alternatives and allocates the calls to the elevators in such a way that the desired cost function is minimized.

(14) It is obvious to a person skilled in the art that different embodiments of the invention are not exclusively limited to the examples described above, but that they may be varied within the scope of the claims presented below.