AU2003262594A1

AU2003262594A1 - Elevator group control method

Info

Publication number: AU2003262594A1
Application number: AU2003262594A
Authority: AU
Inventors: Marja-Liisa Siikonen; Jari Ylinen
Original assignee: Kone Corp
Current assignee: Kone Corp
Priority date: 2002-10-01
Filing date: 2003-09-12
Publication date: 2004-04-23
Anticipated expiration: 2023-09-12
Also published as: CN1688501A; ATE407905T1; EP1549581B1; FI113163B; EP1549581A1; FI20021746A0; AU2003262594B2; ES2310261T3; DE60323518D1; WO2004031062A1

Abstract

The invention concerns a method for controlling the elevators in an elevator group when destination floor call input is used and the traffic within the elevator group is to be optimized. According to the inventive concept of the method, based on traffic intensity, a cost function is optimized by changing the number of cost criteria from one to several and back and weighting the criteria in different ways in the aforesaid cost function.

Description

WO 2004/031062 PCT/F12003/000665 1 ELEVATOR GROUP CONTROL METHOD The present invention relates to a method as defined in the preamble of claim 1 for controlling the eleva 5 tors in an elevator group. The invention relates to an elevator group control method in which destination floor call input is used. 10 Prior art is described in EP patent specification 356731 (B66B 1/20), which discloses an elevator group control system using immediate allocation of destina tion calls, wherein, immediately after the input of a call, the operating costs corresponding to the waiting 15 times of passengers are computed merely for the input floor and the destination floor of the new call. After this, a comparison of these costs is performed, where upon the call is assigned to the elevator with the smallest operating costs. 20 Prior art is also described in FI application document 972937 (B66B 1/20), which discloses an elevator group control system in which the control of the elevators is optimized on the basis of the traffic situation, 25 i.e. the currently prevailing type and intensity of traffic. The prevailing traffic situation is identi fied and the elevator group is controlled on the basis of a predetermined so-called expert rule corresponding to the aforesaid traffic situation. 30 A problem with solutions according to the present state of the art using normal control and zoning for controlling the elevators in an elevator group is that, in quiet traffic conditions, congestion occurs 35 in the elevator lobby when optimization is exclusively applied to the transportation capacity or the travel ing times. To provide room for the passengers in the WO 2004/031062 PCTIFI2003/000665 2 elevator lobby, it would be necessary to build a larger elevator lobby, which again would be too expen sive in large buildings. 5 Another source of problems is the fact that, when nor mal control is used in elevator group control, empty elevators often pass by a floor where passengers are waiting for an elevator, which is annoying to the waiting passengers. This is a problem especially in 10 the case of elevators with glass walls, because pas sengers waiting in the lobby can see the empty eleva tors passing by. The object of the present invention is to overcome the 15 drawbacks encountered in the above-mentioned prior art. A specific object of the invention is to reduce wait ing times in an elevator lobby under quiet traffic in 20 tensity conditions of an elevator group. Congestion of the elevator lobby is thus avoided and the need to build a larger elevator lobby for the waiting passen gers is obviated. In addition, the present invention aims at reducing the lengths of waiting queues in the 25 elevator lobby. For example, by using the elevator group control method of the present invention, the queues during quiet traffic will be of the same order as when a con 30 ventional, normal and continuous allocation method is used, while in an intensive up-peak traffic situation the transportation capacity of the elevator group will exceed the capacity of an elevator group control sys tem using a conventional, normal and continuous allo 35 cation method by about 70 - 100 %.

WO 2004/031062 PCTIFI2003/000665 3 In precise terms, the method of the invention for the control of the elevators in an elevator group is char acterized by what is disclosed in the characterization part of claim 1. The features of some preferred em 5 bodiments of the invention are disclosed in the sub claims. As compared with prior art, the method of the inven tion provides significant advantages. 10 The most important advantage achieved by the present invention is that the method significantly improves passenger service and reduces passenger waiting times in the entrance lobby. In particular, the method of 15 the invention reduces passenger waiting times in the entrance lobby of the elevator group when the traffic intensity for the elevator group is low. Therefore, the queues of passengers waiting for elevators in the elevator lobby are significantly shortened during 20 quiet traffic conditions. In busy traffic conditions, the present invention af fords the advantage of increasing the passenger trans portation capacity of the elevator group. 25 The present invention concerns a method for control ling the elevators in an elevator group when destina tion floor call input is used and the traffic within the elevator group is to be optimized. According to 30 the most preferred embodiment of the present inven tion, based on traffic intensity and traffic type, a cost function is optimized by changing the number of cost criteria from one to several and back and weight ing the criteria in different ways in the aforesaid 35 cost function.

WO 2004/031062 PCTIFI2003/000665 4 According to a second embodiment of the present inven tion, one or more of the following cost criteria of the cost function to be optimized are optimized: wait ing time of passengers, traveling time of passengers, 5 energy consumption, car load factor, transportation capacity and time of arrival of the elevator at floors where passengers are waiting. This optimization method utilizing several optimization criteria to be opti mized in the cost function is more generally called 10 multiobjective optimization, which allows considerably better results to be achieved than when only one opti mization objective is used in the cost function. Further, according to a preferred embodiment of the 15 invention, the cost criteria of the aforesaid cost function to be optimized are weighted by different co efficients depending on traffic intensity. In addition, in a preferred embodiment of the inven 20 tion, it is possible that, in quiet traffic condi tions, only one of the cost criteria of the aforesaid cost function to be optimized is optimized, which cri terion, according to a preferred embodiment of the in vention, is the waiting time of passengers. 25 Further according to the method of the present inven tion, the criteria for the aforesaid quantity to be optimized are changed in the cost function in a manner such that, in low traffic intensity conditions, the 30 waiting time is optimized, while in a more intensive traffic situation the traveling time is optimized, the latter being equal to the passenger waiting time plus the time the passenger stays onboard the elevator. 35 Further according to an embodiment of the invention, the cost criteria of the aforesaid quantity to be op timized are changed in the aforesaid cost function in WO 2004/031062 PCT/F12003/000665 5 a manner such that, when the traffic grows more inten sive, the weighted cost function is optimized so that the weighting of the waiting time decreases while the weighting of the traveling time increases in the 5 aforesaid cost function. According to an embodiment of the invention, zoning is applied to destination floor calls issued from the lobby, and when the zone limits are taken from traffic 10 forecasts, dynamic zoning is employed in the elevator group control during busy traffic. It is further pos sible that dynamic zoning with zone limits taken from traffic forecasts is used in the optimization in the elevator group control during busy traffic when equal 15 numbers of people leave the elevator in each zone. Further according to an embodiment of the invention, one or more of the elevators in the aforesaid elevator group are used to serve two or more zones depending on the transportation need. 20 According to the invention, in the aforesaid elevator group, using a destination floor call input device, the one of the elevators in the elevator group allo cated for each passenger is indicated by the group 25 control system of the elevator group. In the following, the invention will be described in detail with reference to the attached drawings, wherein 30 Fig. 1 represents the method of the invention in dia grammatic form, Fig. 2A and 2B visualize two different embodiments ac 35 cording to the present invention when dynamic zoning is used for optimizing the passenger flow carried by an elevator group in a building, WO 2004/031062 PCT/F12003/000665 6 Fig. 3 shows average waiting times in an up-peak traf fic situation in an elevator group in the cases of dy namic zoning, multiobjective optimization and destina 5 tion-multiobjective optimization. The diagram in Fig. 1 visualizes the method of the in vention, wherein the input of calls to the elevators in the elevator group is implemented using destination 10 floor call input and the traffic within the elevator group is optimized using as a control method either multiobjective optimization or dynamic zoning, depend ing on the intensity and type of the traffic. The ele vator group is controlled by a computer configured for 15 this purpose. Information for use by the group control system of the elevator group is obtained from traffic forecasts re garding the current traffic type and intensity. In 20 forecast statistics, information is collected e.g. from car load weighing devices and/or light cells and/or destination floor call buttons, which can be utilized expressly in connection with destination con trol. From destination call buttons, preferably infor 25 mation representing traffic arrival times and passen gers' floors of arrival and departure is obtained. Thus, the elevator group control system has informa tion available regarding the passengers' floors of destination and departure. Likewise, the car load 30 weighing device and light cells can be used to measure other values descriptive of the traffic, such as move ments of people. In this case, the elevator group con trol system has information available regarding pas sengers entering the elevator and passengers leaving 35 the elevator as well as the load of the elevators and the traveling directions of the passengers on the ele vators. In addition, the energy consumed by the eleva- WO 2004/031062 PCTIFI2003/000665 7 tors can be measured. The aforesaid traffic type of the elevator group has four categories: low traffic, normal traffic, busy traffic and intensive traffic. 5 On the basis of the above-described information, the currently prevailing traffic type and traffic inten sity are determined for the elevator group control system. When multiobjective optimization is utilized in the control, the cost factors to be used in the 10 cost function in each case as well as suitable weight ings for them can be selected using the aforesaid traffic type and intensity data. As an inventive step in the method according to the 15 present invention, the cost function is optimized ac cording to traffic intensity by changing the number of cost functions from one to several and back and weighting them in different ways in the aforesaid cost function. 20 In the method of the invention, the cost factors of the cost function to be optimized include one or more of the following: waiting time of passengers, travel ing time of passengers, energy consumption, car load 25 factor, transportation capacity, elevator arrival time at floors where passengers are waiting. Likewise on the basis of information available to the elevator group control system, the traffic type is de 30 termined. When it is established that the traffic type prevailing in the elevator group is intensive traffic, dynamic zoning is adopted as an optimization method in the optimization process. When a low or normal traffic type prevails, the aforesaid multiobjective optimiza 35 tion method is used. After identifying the traffic type and making a decision regarding the control, the elevator group control system carries out elevator WO 2004/031062 PCT/F12003/000665 8 group control actions to control the elevators in a manner as optimal as possible. When dynamic zoning is adopted in the group control of 5 the elevator group in a busy traffic situation, the zone limits are obtained from traffic forecasts. Zon ing is implemented for destination floor calls issued from the elevator lobby. Likewise, zoning can be acti vated when equal numbers of passengers leave the ele 10 vator in each zone. According to an embodiment of the invention, dynamic zoning is used for optimizing the passenger flow of the elevator group in the group control of the eleva 15 tor group in a busy traffic situation so that passen gers entering from the entrance floor are assigned to zones comprising adaptive zone limits when equal num bers of passengers leave the elevator in each zone. 20 According to another embodiment, dynamic zoning is used for optimizing the passenger flow of the elevator group in the group control of the elevator group in a busy traffic situation so that passengers entering from congested floors are assigned to zones comprising 25 adaptive zone limits when equal numbers of passengers leave the elevator in each zone. One of the basic ideas in the method described above is that in low traffic conditions the waiting times 30 are optimized and in more intensive, i.e. normal traf fic conditions passengers' traveling times are opti mized, while in busy traffic conditions dynamic zoning is used. When the elevator group is controlled accord ing to this method, the queues during low traffic will 35 be of the same order as when normal allocation methods are used, while in a busy traffic situation the trans portation capacity of the elevator group is increased WO 2004/031062 PCT/F12003/000665 9 by about 70 % over the group control of an elevator group using normal allocation methods. Fig. 2A visualizes an embodiment of the invention when 5 dynamic zoning is used for optimizing the passenger flow handled by an elevator group in a building. When zoning is implemented for destination floor calls is sued from the lobby, i.e. from the entrance floor, and when the zone limits are taken from traffic forecasts, 10 dynamic zoning is used in the elevator group control for optimizing the passenger flow in the elevator group in a busy traffic situation when the traffic in tensity of the passenger flow exceeds a given preset limit value. 15 In the situation illustrated in Fig. 2A, dynamic zon ing is used in the elevator group control in the building for optimizing the passenger flow in the ele vator group in a busy traffic situation so that pas 20 sengers entering from the entrance floor are assigned to zones comprising adaptive zone limits vr when equal numbers of passengers leave the elevator in each zone. In the example presented in the figure, 40 passengers enter the elevator group from the entrance floor and 25 their destination floors are distributed equally be tween two different zones (zone 1 & zone 2) . In other words, equal numbers of passengers leave the elevator in each zone (zone 1 & zone 2), although the aforesaid zones (zone 1 & zone 2) comprise different numbers of 30 floors, while the number of passengers leaving the elevator at these floors varies according to the traf fic situation determined by the destination floor calls. 35 The zone limits vr of the aforesaid zones (zone 1 & zone 2) are distributed adaptively so that the zone limits vr vary in the building, allowing floor- WO 2004/031062 PCT/F12003/000665 10 specific optimization of the passenger traffic in the elevator group of the building. This enables the ele vators of the elevator group to serve the most con gested entrance floors in an optimal way in busy traf 5 fic conditions. These aforesaid zone limits vr are ob tained from the traffic forecasts. In the situation illustrated in Fig. 2B, in which pas sengers enter the elevator group from certain con 10 gested floors in the building, dynamic zoning is used in the elevator group control for optimizing the pas senger flow in the elevator group in a busy traffic situation so that the passengers entering from said certain congested floors are assigned to zones com 15 prising adaptive zone limits vr when equal numbers of passengers leave the elevator in each zone. This figure visualizes a traffic situation where, in a zoned building, there are three entrance floors with 20 heaviest traffic, with ten (10) passengers on two of said floors and (20) passengers on one of them waiting to enter the elevator group. The passengers of the elevator group are distributed equally between two zones (zone 1 & zone 2) formed from the passengers' 25 destination floors so that equal numbers (20) of pas sengers leave the elevator in each zone (zone 1 & zone 2). In the situations presented in the aforesaid figures 30 2A and 2B, one or more of the elevators in the eleva tor group are used to serve two or more zones, depend ing on the transportation need. Fig. 3 shows the average waiting times in up-peak 35 traffic conditions in the elevator group as a function of traffic intensity when the group control method used to control the elevator group is dynamic zoning WO 2004/031062 PCT/F12003/000665 11 or multiobjective optimization or traditional control based on up/down call buttons. The results presented in the figure have been obtained by utilizing an ele vator traffic simulator in a building. 5 From this figure we can see that, as elevator group control methods, both dynamic zoning and multiobjec tive optimization are of equal efficiency in busy traffic conditions from a certain traffic intensity 10 limit value upwards. At a certain traffic intensity value, equal waiting times are achieved by both eleva tor group control methods. From Fig. 3 it can also be seen that, when the traffic 15 intensity in the elevator group is below the above mentioned certain traffic intensity value, the waiting times of the passengers of the elevator group differ from each other when dynamic zoning or multiobjective optimization is used as the group control method of 20 the elevator group. Multiobjective optimization here yields considerably shorter passenger waiting times as compared with mere dynamic zoning. In other words, at low traffic intensity values, when multiobjective op timization is used as the group control method of the 25 elevator group, considerably shorter passenger waiting times are achieved as compared with dynamic zoning. Comparing traditional control based on up/down buttons to multiobjective optimization at low traffic inten sity values, the waiting times are equally short. In 30 traditional control, the waiting times start increas ing steeply when the transportation capacity limit of the control system is exceeded. Via multiobjective op timization, in low traffic conditions short waiting times are obtained, but also a much greater transpor 35 tation capacity is achieved than with traditional con trol. Thus, based on the above comparison, multiobjec tive optimization allows shorter waiting times to be WO 2004/031062 PCTIFI2003/000665 12 achieved at all traffic intensity values, thereby also significantly shortening the queues of passengers in elevator lobbies. 5 In the foregoing, the invention has been described by way of example with reference to the attached drawings while different embodiments of the invention are pos sible in the scope of the inventive concept defined in the claims. 10

Claims

1. Method for controlling the elevators in an elevator group when destination floor call input is used and 5 the traffic within the elevator group is to be opti mized, characterized in that, based on traffic inten sity and traffic type, a cost function is optimized by changing the number of cost criteria from one to sev eral and back and weighting the criteria in different 10 ways in the aforesaid cost function.

2. Method according to claim 1, characterized in that, one or more of the following cost criteria of the aforesaid cost function to be optimized are optimized: 15 waiting time of passengers, traveling time of passen gers, energy consumption, car load factor, transporta tion capacity and time of arrival of the elevator at floors where passengers are waiting. 20 3. Method according to claim 2, characterized in that the cost criteria of the aforesaid cost function to be optimized are weighted by different coefficients de pending on traffic intensity. 25 4. Method according to any one of the preceding claims, characterized in that, in quiet traffic condi tions, only one of the cost criteria of the aforesaid cost function to be optimized is optimized. 30 5. Method according to claim 4, characterized in that, in quiet traffic conditions, of the cost criteria of the aforesaid cost function to be optimized, the wait ing time of passengers is optimized. 35 6. Method according to any one of the preceding claims, characterized in that the criteria for the aforesaid quantity to be optimized are changed in the WO 2004/031062 PCTIFI2003/000665 14 aforesaid cost function in a manner such that, in low traffic intensity conditions, the waiting time is op timized, while in a more intensive traffic situation the traveling time is optimized. 5

7. Method according to any one of the preceding claims, characterized in that the cost criteria of the aforesaid quantity to be optimized are changed in the aforesaid cost function in a manner such that, when 10 the traffic grows more intensive, the weighted cost function is optimized so that the weighting of the waiting time decreases while the weighting of the traveling time increases in the aforesaid cost func tion. 15

8. Method according to any one of the preceding claims, characterized in that, when zoning is applied to destination floor calls issued from the lobby and when the zone limits are taken from traffic forecasts, 20 dynamic zoning is used in the group control of the elevator group in busy entering traffic conditions.

9. Method according to claim 8, characterized in that 25 dynamic zoning is used in the elevator group control for the optimization of the passenger flow in the ele vator group during busy traffic so that passengers en tering from the entrance floor are assigned to zones comprising adaptive zone limits when equal numbers of 30 people leave the elevator in each zone.

10. Method according to claim 8, characterized in that dynamic zoning is used in the group control of the elevator group for optimizing the passenger flow in 35 the elevator group in a busy traffic situation so that passengers entering from certain congested floors are assigned to zones comprising adaptive zone limits when WO 2004/031062 PCTIFI2003/000665 15 equal numbers of passengers leave the elevator in each zone.

11. Method according to claim 8 or 9 or 10, character 5 ized in that one or more of the elevators in the aforesaid elevator group are used to serve two or more zones according to the transportation need.

12. Method according to any one of the preceding 10 claims, characterized in that in the aforesaid eleva tor group, using a destination floor call input de vice, the one of the elevators in the elevator group allocated for each passenger is indicated by the group control system of the elevator group.