EP1760025A1

EP1760025A1 - Elevator group control system and control method thereof

Info

Publication number: EP1760025A1
Application number: EP06017909A
Authority: EP
Inventors: Toshifumi Yoshikawa; Satoru Toriyabe; Takamichi Hoshino; Shunichi Tanae; Atsuya Fujino; Masaya Furuhashi; Kenji Yoneda; Ryo Okabe; Keiichi Aida; Masaaki Tamada
Original assignee: Hitachi Ltd; Hitachi Mito Engineering Co Ltd
Current assignee: Hitachi Ltd; Hitachi Mito Engineering Co Ltd
Priority date: 2005-08-31
Filing date: 2006-08-28
Publication date: 2007-03-07
Anticipated expiration: 2026-08-28
Also published as: JP2007062927A; TW200718633A; DE602006015265D1; JP4567553B2; TWI316506B; CN100586828C; CN1923658A; EP1760025B1

Abstract

In view of the limited effect of the elevator car (12A, 12B, 12C) interval control by hall call assignment alone, depending on generation of hall calls, an elevator group control system and a control method thereof are disclosed, in which the waiting time can be shortened more accurately in finely detailed fashion. A reference trajectory indicating a reference position of each elevator car (12A, 12B, 12C) within a predetermined future time is prepared for each elevator car (12A, 12B, 12C), and a forecasted trajectory corresponding to the reference trajectory is prepared by forecasting the position of each elevator car (12A, 12B, 12C). A hall call is assigned in such a manner that the forecasted trajectory approaches the reference trajectory. At the same time, the operation control factors other than assignment, including the car speed (car speed and acceleration) and the stop time (the door operation speed and the door opening time) of each elevator car (12A, 12B, 12C) are adjusted during the period lacking the assignment process.

Description

BACKGROUND OF THE INVENTION

This invention relates to an elevator group control system and a control method for controlling a plurality of elevator cars collectively as one group.
An elevator group control system provides a more efficient transportation service to users by handling a plurality of elevator cars as one group. Specifically, a plurality of elevator cars (normally, three to eight elevator cars) are controlled as one group, and in the case where a hall call is generated from a given floor, the optimum elevator car is selected from this group and the hall call is assigned to the particular elevator car.
The conventional group control system basically controls the assignment according to the assignment evaluating function based on the forecasted waiting time. Specifically, in the case where a new hall call is generated, the forecasted waiting time is calculated for each hall call (a new hall call and a hall call yet to be served) held by each car and an elevator car associated with a minimum waiting time or an elevator car associated with a minimum maximum waiting time is assigned the particular hall call. This control operation, though basically employed for group control by each elevator maker, has two problems described below.

(1) An optimum car is assigned to a hall call already generated, and the effect of a future call is not taken into consideration.
(2) A call is assigned to a given car with the forecasted waiting time as an index, and the relative positions of the cars is not taken into consideration.

In order to solve this problem of the assignment method based on the forecasted waiting time, various control methods have been proposed in the past. The basic concept of these control methods is to run the elevator cars at equal time intervals. In the case where the elevator cars are not uniformly arranged, i.e. the time interval between a given pair of cars is longer than those of the others, a new hall call, if generated between the particular car pair, is liable to wait for a longer time before service. As long as the cars can be arranged at equal time intervals, the case of a long waiting time can be suppressed. The conventional control methods intended for elevator car arrangement at equal time intervals are listed below.

(1) Equidistance priority zone control ( JP-A-1-226676 )
(2) Equidistance priority zone and deferred zone control ( JP-A-7-11794 )
In these two methods, floors to be served by a car are set in a priority zone and a deferred zone, and an assignment evaluate value is manipulated in such a manner that a new hall call located in the priority zone is assigned easily, and a new call located in the deferred zone is assigned less easily with the intention that the distance between the cars approaches an equal time interval.
(3) Assignment evaluating control using equal time interval as an index ( JP-B-7-72059 )
The arrangement of the cars at a future time point is forecasted, and based on this forecast, the time interval of each car at the particular time point is forecasted. From this forecasted time interval of the cars, the assignment limiting evaluate value is calculated to control the assignment in such a manner that the cars are not concentrated on a part of the floors with the intention of locating the cars at as equal time intervals as possible.
(4) Assignment method based on position evaluate value ( JP-A-2000-118890 )
In this method, the position evaluate value of each car is calculated in such a manner that the car arrangement is not unbalanced, and based on an assignment evaluate value taking this position evaluate value into consideration, the assignment of a hall call is determined. This position evaluate value is calculated based on the relation, upon generation of a hall call, between the absolute position of a given car and the average value of the absolute positions of the other cars. This method is also intended to arrange the cars uniformly.

None of the conventional techniques described above provides a final solution to achieve the uniform car arrangement and equal time intervals of the cars. The greatest reason is that the assignment has its own limitation. In each conventional method, the equal time interval is assessed in car assignment in response to a hall call. In view of the fact that hall calls are random in both position and time of generation, the assignment is accompanied by the limited selectable cars to be assigned. Therefore, the control operation is unexpectedly difficult. In the case where two elevator cars are in proximity to each other, for example, a hall call, if generated from a floor between the two cars, can be assigned to the following elevator car and thus the interval between the two cars can be increased. Actually, however, a hall call is not always generated so conveniently and properly in terms of both position and time. The generation of a hall call is a request of a man to move after all and considered unpredictable. The control operation depending on the hall call generation alone has its own limit.

SUMMARY OF THE INVENTION

Accordingly, an object of this invention is to solve this problem of the conventional techniques and to control the cars more properly in positions at equal time intervals.
According to one aspect of the invention, there are provided an elevator group control system for controlling a plurality of elevator cars serving a plurality of floors, wherein a reference trajectory indicating a future reference position is prepared for each elevator car, and the future position of each elevator car is forecasted thereby to prepare a forecasted trajectory corresponding to the reference trajectory. Then, the car speed and the car stop time of each elevator car or the stop position of a waiting elevator car to which a car call and a hall call are not assigned are adjusted in such a manner that the forecasted trajectory approaches the reference trajectory.
According to another aspect of the invention, there are provided an elevator group control system and a control method, wherein the future position of each elevator car is forecasted and a hall call generated is assigned to an elevator car in such a manner as to equalize the intervals between the elevator cars on the one hand and the car speed and the car stop time of other than the assigned elevator car or the stop position of a waiting elevator car are adjusted in such a manner as to equalize the intervals between the elevator cars.
According to still another aspect of the invention, there are provided an elevator group control system and a control method, wherein a reference trajectory indicating a reference position of each elevator car at a time point within a predetermined future time is prepared for each elevator car, and a forecasted trajectory corresponding to the reference trajectory is prepared by forecasting the position of each elevator car at a time point within the predetermined future time. A hall call generated is assigned to an elevator car in such a manner the forecasted trajectory approaches the reference trajectory. During the period when there is no unassigned hall call, the car speed and the car stop time of the elevator cars other than the assigned elevator car or the stop position of a waiting elevator car is adjusted in such a manner that the forecasted trajectory approaches the reference trajectory.
According to a preferred embodiment of the invention, the means for adjusting the car speed of an elevator car includes a means for adjusting the car speed or acceleration, and the means for adjusting the elevator stop time includes a means for adjusting the door operation speed and the door opening time of an elevator car or the door operation select operation of a waiting elevator car.
According to a preferred embodiment of the invention, a plurality of elevator cars can be controlled to positions at as equal time intervals as possible both accurately and finely thereby to shorten the waiting time of users.
The above and other objects, features and advantages will be made apparent by the detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a functional block diagram for controlling an elevator group control system according to a first embodiment of the invention.
Fig. 2 is a first diagram showing an example of the control operation of an elevator group control system according to the first embodiment of the invention.
Fig. 3 is a second diagram showing an example of the control operation of an elevator group control system according to the first embodiment of the invention.
Fig. 4 is a flowchart showing the process of preparing a reference trajectory according to an embodiment of the invention.
Fig. 5 is a graph illustrating specific contents of the process described with reference to Fig. 4.
Fig. 6 is a functional block diagram for controlling an elevator group control system according to a second embodiment of the invention.
Fig. 7 is a first diagram showing an example of the control operation of an elevator group control system according to a second embodiment of the invention.
Fig. 8 is a second diagram showing an example of the control operation of an elevator group control system according to the second embodiment of the invention.
Fig. 9 is a functional block diagram for controlling an elevator group control system according to a third embodiment of the invention.
Fig. 10 is a flowchart showing the process of calculating the reference interval value according to the third embodiment of the invention.
Fig. 11 is functional block diagram for controlling an elevator group control system according to a fourth embodiment of the invention.
Fig. 12 is a flowchart showing the process according to the embodiment explained with reference to Fig. 11.
Fig. 13 is functional block diagram for controlling an elevator group control system according to a fifth embodiment of the invention.
Fig. 14 is a flowchart showing the process according to the embodiment explained with reference to Fig. 13.

DESCRIPTION OF THE INVENTION

Embodiments of the invention are explained below with reference to the drawings.
Fig. 1 is a functional block diagram for controlling an elevator group control system according to a first embodiment of the invention. A group control system is configured of a group control unit 10, individual controllers 11A to 11C for the respective elevator units 12A to 12C and the elevator units 12A to 12C. The elevator units 12A to 12C are collected in one group and collectively controlled by the group control unit 10. Specifically, the information for each elevator unit such as the position, direction, speed, hall call, car call and the number of passengers are collected in the group control unit 10 through the individual controllers 11A to 11C. Based on these information, the group control unit 10 generates an appropriate elevator operation command and issues it to each of the individual controllers 11A to 11C thereby to control the operation of the elevator units 12A to 12C.
The group control unit 10 constituting the essential part of the invention is explained in detail below.
In the group control unit 10, the information collected from the individual controllers 11A to 11C are stored in the information collector 1. The information held in the information collector 1 includes the information on each elevator unit, the information on the calls assigned to each elevator and the information on the traffic of the building in which the elevator units are installed. The information on each elevator unit includes the position, direction, speed and acceleration of each car and a hall call assigned to each car, a car call generated, number of passengers in the car and the elevator door condition. The information on a call assigned to each elevator car includes the time elapsed from the generation of each hall call and the forecasted waiting time. Further, the information on the traffic of the particular building include the present traffic pattern of the building, the average stop probability at each floor, the average stop time at each floor and the OD (origin-designation) matrix. Using the information of the information collector 1, the forecasted trajectory preparation unit 3 prepares a forecasted trajectory described later. The forecasted trajectory is, in short, the future trajectory (locus) of each elevator car forecasted on time axis. Further, the reference trajectory preparation unit 2 prepares the reference trajectory described below using the information of the information collector 1 and the forecasted trajectory. The reference trajectory is, in short, an intended trajectory (locus) plotted on the time axis for each elevator car. The intended trajectory is defined basically as a trajectory for leading to equal time intervals. The method of preparing the reference trajectory is explained in detail later. The trajectory error evaluating unit 4 calculates the error between the reference trajectory and the forecasted trajectory. The trajectory error is defined as an index quantitatively assessing the degree of discrepancy between the trajectories as an error. Specific examples of the reference trajectory and the forecasted trajectory are shown in Fig. 2, and each expressed by a line on the time axis. The area defined by the two lines, therefore, is an index indicating the error between the trajectories.
The trajectory adjust operation setting unit 5 sets various trajectory adjust means in the trajectory adjust means 6 other than assignment and an adjustment amount (adjustment parameter amount) thereof. The trajectory adjust operation set by the trajectory adjust operation setting unit 5 has an effect on the shape of the forecasted trajectory. In other words, the forecasted trajectory is adjusted by the trajectory adjust operation setting unit 5 to make a more appropriate shape (state) of the forecasted trajectory. Once the trajectory adjust operation is set by the trajectory adjust operation setting unit 5, therefore, a forecasted trajectory (adjusted forecasted trajectory) is computed anew by the trajectory adjust operation setting unit 5. Also with regard to this adjusted forecasted trajectory computed anew, the trajectory error evaluating unit 4 assesses the error between the reference trajectory and the forecasted trajectory. The trajectory adjust operation is performed in a plurality of ways by changing the adjust means and the adjust amount described later. Nevertheless, the trajectory adjust operation may be carried out only once or never. Thus, a trajectory error evaluate value corresponding to each of a plurality of adjust operation cases is calculated. Among the plurality of the cases, an adjust operation case having the smallest error evaluate value, i.e. an adjust operation case generating an adjusted forecasted trajectory nearest to the reference trajectory is selected as a trajectory adjust means to be actually carried out.
The trajectory adjust means 6 for other than assignment is a mass of specific trajectory adjust means capable of adjusting a forecasted trajectory by the operation other than the hall call assignment. According to this embodiment, seven trajectory adjust means are prepared, including (1) the car speed adjustment, (2) the car acceleration adjustment, (3) the door operation speed adjustment, (4) the door opening time adjustment, (5) the selection of the door operation state of a waiting car, (6) the close button valid/invalid selection, and (7) waiting position adjustment. These seven adjust operations are roughly classified into (a) the adjustment of car speed, (b) the stop time adjustment, and (c) the stop position adjustment. The item (a) adjustment of car speed is associated with (1) car speed adjustment and (2) car acceleration adjustment, and the item (b) the stop time adjustment is associated with (3) the door operation speed adjustment, (4) the door opening time adjustment, (5) the selection of the door operation state in waiting time and (6) the close button valid/invalid selection. Further, the item (c) the stop position adjustment is associated with (7) the waiting position adjustment. Especially, (a) the adjustment of car speed and (b) the stop time adjustment have a large effect on adjustment of the forecasted trajectory, (a) the car speed adjustment adjusts the inclination of the forecasted trajectory, and (b) the stop time adjustment adjusts the stop time length of the forecasted trajectory remaining the same.
An operating condition determining unit 9 of the operation means determines which one of the trajectory adjust means 6 is applicable based on the information of the information collector 1. Also, the upper and lower limits of the adjust amount of each adjust means is defined based on the same information. In the case where passengers in the car is small in number or zero, for example, the adjustment of car speed (especially, adjustment for decreasing the speed) is applicable. This is intended to suppress the effect of deteriorating the serviceability as far as possible by decreasing the speed. In a situation where the elevator utilization factor is high (during rush hours, for example), on the other hand, the adjustment of door operation speed may be made inapplicable to secure safety.
In a trajectory adjust operation determining unit 7, the trajectory error evaluate values for a plurality of trajectory adjust operation cases (among which adjust means and adjust amount are varied) set in the trajectory adjust operation setting unit 5 are compared with each other, and a case with the smallest error evaluate value is selected as an operation case to be actually performed. The "smallest error evaluate value" is indicative that the adjusted forecasted trajectory is nearest to the reference trajectory. By selecting this adjust means, therefore, the forecasted trajectory can be made to gradually approach the reference trajectory. For example, assume that there are two adjust operation cases, i.e. a case in which the car speed is decreased to 10 % below the rated speed (in adjust amount) and a case in which the car speed is decreased to 30 % below the rated speed, by a car speed adjust means. The latter case, i.e. 30 % lower than the rated speed, if smaller in trajectory error evaluate value, is selected.
A trajectory adjust command unit 8, in order to actually carry out the trajectory adjust means selected by the trajectory adjust operation determining unit 7, transmits a control command to the individual controllers 11A to 11C of the elevator units. As a result, the adjust operation is carried out by the individual controllers 11A to 11C in accordance with the control command. As an example, a control command to decrease the speed of the second elevator car to 30 % below the rated speed is sent so that the second elevator car may follow the reference trajectory.
Fig. 2 is a diagram showing an example of the control operation of the elevator group control system according to the first embodiment of the invention. Especially, an example of trajectory adjust operation is shown in which the car speed of the elevator car, i.e. (1) the car speed is adjusted. In Fig. 2, the number of elevator cars controlled as a group is set to two and the number of floors is set to five to avoid complication. First, the state before trajectory adjust operation is explained with reference to Fig. 2(a). The left diagram in Fig. 2(a) shows the present position and direction of the cars by a ring expression. The ring expression is a method in which each floor is divided into two directions, up and down, and each elevator car making one round is plotted as if running along a ring. At the present time, a first car 101 is moving up at the first floor and a second car 102 is moving up at the third floor. In the right diagram of Fig. 2, on the other hand, the abscissa represents the time axis with the present time point as an origin, and the ordinate the position (floor). In the abscissa representing the time axis, the right side of the origin (present time point) indicates the future. The position and direction of each elevator car at the present time point is the same as the position in the ring expression in the left diagram. The solid locus drawn from each elevator car indicates a forecasted trajectory. The forecasted trajectory of the first car is indicated by a solid locus 103, and the forecasted trajectory of the second car by a solid locus 104. These forecasted trajectories are computed by the forecasted trajectory preparation unit 3 shown in Fig. 1. The two forecasted trajectories show that the two cars are too near to each other and assume what is called a crowded operation state. Upon generation of a new hall call distant (in terms of time or floor) from the two forecasted trajectories, therefore, the time before arrival at the particular hall is lengthened and a long waiting time is caused. To avoid this situation, the elevator cars are required to be operated at equal time intervals, and in the case under consideration, the phase of the forecasted trajectory of the first car is required to be delayed more. Thus, the reference trajectory of the first car should be set as indicated by one-dot chain 105. This reference trajectory 105 is prepared by the reference trajectory preparation unit 2 shown in Fig. 1.
Fig. 2(b) shows the state after the trajectory adjust operation (speed adjust operation). In the trajectory adjust operation setting unit 5 and the trajectory adjust operation determining unit 7 shown in Fig. 1, the adjust means is selected in such a manner that the forecasted trajectory 103 approaches the reference trajectory 105 of the first car in Fig. 2(a). An example of the result of this adjust operation is shown on the right side of Fig. 2(b). In the shown case, (1) the car speed adjustment is used as a trajectory adjust means. The solid line 103A on the right side of Fig. 2(b) shows a forecasted trajectory adjusted by the car speed adjust means. This is a state in which the car speed adjust means is selected by the trajectory adjust operation setting unit 5, and by setting the adjust amount at 40 % delay behind the rated value, an adjusted forecasted trajectory is computed anew in the forecasted trajectory preparation unit 3. The adjusted forecasted trajectory 103A assumes a more gentle curve than the forecasted trajectory 103 shown in Fig. 2(a), indicating that the car speed is decreased. As a result, the reference trajectory 105 of the first car can be rendered substantially coincident with the forecasted trajectory 103A, and the trajectory error evaluate value is very small. Thus, the trajectory adjust operation determining unit 7 shown in Fig. 1 may probably select this adjust means, i.e. the method of decreasing the car speed to 40 % of the rated speed. As a result, the first car is actually liable to assume the locus similar to the adjusted forecasted trajectory 103A, with the result that the first and second cars are guided and controlled into an operation at equal time intervals, i.e. an operation with a temporal equidistance.
Fig. 3 is a second diagram showing an example of the operation of controlling the elevator group control system according to the first embodiment of the invention. Fig. 3(a) shows the state before trajectory adjust operation, and Fig. 3(b) the state after trajectory adjust operation (stop time (door opening time, door operation speed, etc.) adjustment). This case represents an example of operation in which the trajectory adjust means carries out (b) the adjustment of elevator car stop time including (3) the adjustment of the door operation speed and (4) the adjustment of the door opening time. In Fig. 3, the same component elements as those in Fig. 2 are designated by the same reference numerals, respectively, and not described again. Also, Fig. 3(a) is identical with Fig. 2(a) and not explained again. The difference from Fig. 2 lies in that the forecasted trajectory adjust operation is (b) the elevator stop time adjustment. The result is indicated by the shape of the forecasted trajectory 103B shown in Fig. 3(b). Specifically, the adjusted forecasted trajectory 103B shown in Fig. 3(b) is longer in stop time than the forecasted trajectory 103 (before adjustment) shown in Fig. 3(a). As a result, the forecasted trajectory 103B shown in Fig. 3(b) is longer in stop time length along the time axis and approaches the reference trajectory 105. In the forecasted trajectory 103B, the car speed is not adjusted and therefore the trajectory inclination is the same as that of the forecasted trajectory 103.
As illustrated above in Figs. 2 and 3, the reference trajectory can be approached by the forecasted trajectory either by (a) adjusting the car speed (adjusting the trajectory curve inclination) or by (b) adjusting the stop time (adjusting the stop time length). Specific means for each method are shown above in (1) to (2) and (3) to (6), respectively. The stop time can be lengthened, for example, by decreasing the door operation speed or lengthening the door opening time (time length after the door opens till the door is automatically closed). Also, by selecting the door of the waiting elevator car in open state in advance, the stop time can be shortened by the time length otherwise required for the door to open. Further, by setting the elevator close button in invalid state, the elevator cannot be started until the door is automatically closed and therefore the stop time is lengthened.
In addition to the methods (a) and (b) described above, the shape of the forecasted trajectory can be adjusted by adjusting the position of the waiting elevator car directly. The service is the top priority for the elevator car in service, and therefore the position of the elevator car in service cannot be adjusted arbitrarily. As for the waiting elevator car not in service, on the other hand, the waiting position can be adjusted arbitrarily.
Next, the process of preparing the reference trajectory is explained with reference to Figs. 4 and 5. This process is executed by the reference trajectory preparation unit 2 shown in Fig. 1. First, the reference trajectory preparation process is explained with reference to Fig. 4.
Fig. 4 is a flowchart showing the process of preparing the reference trajectory according to an embodiment of the invention. In the graph A01 of Fig. 4, the abscissa represents the time axis and the ordinate the position. The axis A02 indicates the present time point, and the axis A03 the adjust reference time axis. The space between the axis A02 indicating the present time point and the adjust reference time axis A03 is named the adjust area (described in detail later). The reference trajectory is prepared following the process described below.
First, (1) a forecasted trajectory of each car is prepared (ST1), and then (2) the temporal position of each elevator car is on the adjust reference time axis A03 is calculated (ST2). The temporal position is defined as the position measured by time instead of by distance. In this case, the car position at a predetermined time later (corresponding to the time on the adjust reference time axis) is forecasted based on the forecasted trajectory, and this position is determined based on the temporal position. Then, (3) based on the temporal position of each car, the adjust amount of each car position is calculated to secure equal time intervals, i.e. temporal equidistance (ST3). In other words, the position adjust amount for securing the temporal equidistance is calculated from the temporal position of each car at a predetermined time later. Finally, (4) in accordance with the calculated adjust amount, the grid (described later) of the forecasted trajectory is adjusted in the adjust area. The resultant trajectory constitutes a reference trajectory (ST4).
Fig. 5 is a graph illustrating the specific contents of the process explained with reference to Fig. 4. Fig. 5(a) shows a forecasted trajectory computed by the forecasted trajectory preparation process (ST1). In this case, the group supervision is intended for a 10-storied building having three elevator cars. In the graph of Fig. 5(a), like Fig. 4, the abscissa represents the time and the ordinate the position. The axis C050 is the time axis indicating the present time point, and the axis C02A the adjust reference time axis. The space between the two axes represents the adjust area.
At the present time point, the first car C010 is directed down at the eighth floor, the second car C020 directed down at the third floor, and the third car C030 directed down at the fourth floor. The forecasted trajectory of the first car is indicated by solid locus C011, the forecasted trajectory of the second car by the locus C021 indicated by one-dot chain and the forecasted trajectory of the third car is given by the locus C031 of dashed line. According to the process shown in Fig. 4, the temporal position of each car on the adjust reference time axis is calculated from the forecasted trajectory (ST2 in Fig. 4). The position of a given car can be determined by observing the intersection between the forecasted trajectory of the particular car and the adjust reference time axis in Fig. 5(a). The intersection between the forecasted trajectory C011 of the first car and the adjust reference time axis C040 show, for example, that the first car is located between the fourth and third floors and directed down. The temporal position can be calculated based on the time required before reaching the aforementioned position from the upward starting point on the first floor. Once the temporal position is calculated, the adjust amount to secure the equal time intervals, i.e. a temporally equidistant state is determined (ST3 in Fig. 4). The position associated with the equal time intervals is determined from the position of each car on the adjust reference time axis C040 in Fig. 5(a), as indicated by black circles on the adjust reference time axis C040. The black circle C01A, for example, indicates the position of the first car associated with equal time intervals. In similar manner, the black circle C02A indicates the position of the second car associated with equal time intervals, and the black circle C03A the position of the third car associated with equal time intervals. The difference between the position associated with equal time intervals and the position of each car on the adjust reference time axis is the adjust amount. In accordance with this adjust amount, the grid of the forecasted trajectory within the adjust area is adjusted thereby to prepare each reference trajectory (ST4 in Fig. 4). The resultant reference trajectories are shown in Fig. 5(b). Specifically, in Fig. 5(b), the reference trajectory of the first car is indicated by solid line CO11N, the reference trajectory of the second car by one-dot chain C021N, and the reference trajectory of the third car by dashed line C031N. With regard to the forecasted trajectory of each car shown in Fig. 5(a), the grid in the adjust area is adjusted in accordance with the adjust amount so as to pass through the point (black circle) associated with equal time intervals. The grid indicates the point where the direction of each trajectory is turned back. By moving the grid rightward or leftward, the phase of the forecasted trajectory is adjusted so as to pass the coordinate point (in terms of time or position) of the black circle indicating the position associated with equal time intervals. In fact, in Fig. 5(b), the grid of the forecasted trajectory shown in Fig. 5(a) is adjusted so that the trajectory of each car passes through the coordinate point (C01A to C03A) of the black circle associated with equal time intervals. It is understood that on and after the adjust reference time axis, the trajectories are located at equal time intervals.
A method of preparing a reference trajectory is described above. The features of the reference trajectories shown in Fig. 5(b) can be summarized as follows: (1) the locus of each car up to the adjust area represents a transient state leading to equal time intervals, and (2) the locus of each car beyond the adjust area is associated with equal time intervals. In other words, the time intervals of the car trajectories are equal to each other. The reference trajectories shown here, therefore function as a guide to lead the locus of each car to achieve equal time intervals a predetermined time after the present car position. The trajectory adjust operation described with reference to Fig. 1 is carried out so as to approach these reference trajectories functioning as a guide. Thus, the actual trajectory can be rendered to approach the reference trajectory and lead to the state of equal time intervals.
Fig. 6 is a functional block diagram for controlling the elevator group control system according to a second embodiment of the invention. In Fig. 6, the same component elements as those in Fig. 1 are designated by the same reference numerals, respectively, and not described any further. The difference between Figs. 6 and 1 lies in that the configuration of Fig. 6 lacks the reference trajectory preparation means 2 and the trajectory error evaluating unit 4 in Fig. 1, which are replaced by the trajectory state evaluating unit 20.
First, the difference of the control concept between the configurations of Figs. 1 and 6 is explained, followed by the explanation of specific processes. In Fig. 1, a reference trajectory and a forecasted trajectory are computed, and the shape of the forecasted trajectory is adjusted to approach the reference trajectory. Thus, the adjust means whereby both approach most closely to each other is selected. In Fig. 6, on the other hand, a forecasted trajectory is computed, and the state (time interval, for example) of the forecasted trajectory a predetermined time later is evaluated as an evaluate value. Like in Fig. 1, the shape of the forecasted trajectory is adjusted by trajectory adjust means, and an adjust means associated with the highest evaluate value is selected. Specifically, only a forecasted trajectory is used without using a reference trajectory, and by assessing the state of the forecasted trajectory, an appropriate trajectory adjust means is selected thereby to lead to the state of equal time intervals.
Only the points different from Fig. 1 are described in detail below. In the forecasted trajectory preparation unit 3, the forecasted trajectory of each car is prepared, after which the state of the forecasted trajectory is evaluated by the trajectory state evaluating unit 20. The trajectory state evaluating unit 20 assesses the relative positions of the cars a predetermined time later based on the forecasted trajectory of each car. The relative positions are assessed by the time interval, and an evaluating function is set to secure a high evaluate value for a high degree of the state of equal time intervals. For example, the variance of the time interval of each car is selected as an evaluating function. In this case, the smaller the evaluating function, the variance can be regarded to be smaller and the degree of the state of equal time intervals to be higher. The operation of the trajectory adjust operation setting unit 5 and the trajectory adjust means 6 is the same as that of Fig. 1, and the trajectory shape is adjusted by adjusting the car speed and the stop time. The evaluate value of the adjusted forecasted trajectory is also calculated by the trajectory state evaluating unit 20. As in the case of Fig. 1, the evaluate value is calculated for each of a plurality of adjust operation cases, and the adjust means having the highest evaluate value is selected by the trajectory adjust operation determining unit 7. In the trajectory adjust command unit 8, the selected adjust means is transmitted to the individual controllers 11A to 11C of the elevator cars to perform the actual operation.
Fig. 7 shows an example of the control operation of the group control system according to the second embodiment of the invention. Fig. 7, like Fig. 2, shows an example of the operation of adjusting the elevator car speed (adjustment of the car speed, for example) as a trajectory adjust means. In Fig. 7, the same component elements as those in Fig. 2 are designated by the same reference numerals and not described any more. Fig. 7 is different from Fig. 2 in that no reference trajectory is computed and instead, a state evaluating time 110 for state evaluating is set in Fig. 7. Fig. 7(a) shows the situation before the forecasted trajectory adjust operation, in which the time interval of each car is evaluated from the position of each car on the forecasted trajectory at the state evaluating time 110. This evaluating process is carried out by the trajectory state evaluating unit 20. As understood from Fig. 7(a), the time interval between two elevator cars is apparently too small in this case. Fig. 7(b), on the other hand, shows the forecasted trajectory after adjusting the car speed of the second car. As understood, the speed of the second car is set so low that the inclination of the forecasted trajectory 103C of the second car is gentle. Also in this case, the time interval is assessed by the trajectory state evaluating unit 20 shown in Fig. 6 based on the forecasted position of each car at the state evaluating time 110. As the result of the trajectory adjust operation, the phase of the forecasted trajectory of the second car is delayed to achieve the appropriate time interval between the two elevator cars. This adjust means is carried out upon determination that the comparison of the evaluate values shows that this trajectory adjust means is most proper.
Fig. 8 shows a second example of the control operation of the group control system according to the second embodiment of the invention. Fig. 8(a) shows the forecasted trajectory before the adjust operation, and Fig. 8(b) the forecasted trajectory after the adjust operation (adjustment of the door opening time, the door operation speed, etc.). Fig. 8 shows an example different from Fig. 7, and like Fig. 3, shows an example of the operation of the forecasted trajectory adjust means to adjust the stop time of the elevator car, i.e. the door opening time, the door operation speed, etc. In Fig. 8, the same component elements as those in Fig. 3 are designated by the same reference numerals, respectively, and not described any further. In the case of Fig. 7, the car speed is adjusted, while in Fig. 8, the stop time of the second car is adjusted in such a manner that the stop time is longer for the forecasted trajectory 103D of the second car shown in Fig. 8(b) than for the forecasted trajectory 103 of the second car in Fig. 8(a). Also in this case, like in Fig. 7, the time interval of the forecasted trajectory of each car is assessed at the state evaluating time 110. As compared with the case shown in Fig. 8(a), the forecasted trajectory of each car in Fig. 8(b) is apparently improved in the state of equal time intervals, and this adjust means is carried out if assessed with the highest evaluate value among the plurality of the adjust operation cases.
Fig. 9 is a functional block diagram for controlling the elevator group control system according to a third embodiment of the invention. In Fig. 9, the same component elements as those in Fig. 1 are designated by the same reference numerals, respectively, and not described any more. The difference between Figs. 9 and 1 lies in that (1) the reference trajectory computing unit (Fig. 1-2) is replaced by the reference interval setting unit (Fig. 9-30) and (2) the trajectory error evaluating unit (Fig. 1-4) is replaced by the interval error evaluating unit (Fig. 9-31).
First, the difference of the control concept between the configurations shown in Figs. 1 and 9 is explained, after which specific processing steps are explained. In Fig. 1, a reference trajectory and a forecasted trajectory are prepared, and the shape of the forecasted trajectory is adjusted to approach the reference trajectory. In Fig. 9, on the other hand, a reference interval for the forecasted trajectory of each elevator car is set and the shape of the forecasted trajectory is adjusted to approach the reference interval. Specifically, a trajectory adjust means is selected in which the interval value of the forecasted trajectory a predetermined time later is compared with the reference interval value, and the forecasted trajectory is so shaped as to reduce the error. From the viewpoint of reference control, the trajectory indicating the locus of the elevator car position on the time axis is controlled to a reference state according to the first embodiment shown in Fig. 1, while the forecasted trajectory of each car is controlled in such a manner that the elevator car interval approaches a reference value in the near future according to the embodiment shown in Fig. 9.
The component elements of this embodiment different from those of Fig. 1 are explained in detail below. The reference interval setting unit 30 sets a reference interval value associated with equal time intervals of the elevator cars from the expectation value (prediction value) of the one round trip time of the elevator cars in the traffic condition prevailing at the particular time point. The reference interval value is a time interval value expressed by time. In the case where the expectation value of the one round trip time is 60 seconds and three elevator cars are in operation, for example, the reference time interval realizing equal time intervals is 20 seconds. The forecasted trajectory computing unit 3 prepares the forecasted trajectory of each car. The interval error evaluating unit calculates the time interval value of each car at a predetermined time later based on the forecasted trajectory of each car, and also calculates the error between this value and the reference interval value. The smaller the error from the reference interval, the nearer to the reference interval and the nearer to the state of equal time intervals. The operation of the trajectory adjust operation setting unit 5 and the trajectory adjust means 6 are the same as that in Fig. 1, and the trajectory shape is adjusted by adjusting the running speed and the stop time. Also with regard to the forecasted trajectory after this adjustment, the error from the reference interval is calculated by the interval error evaluating unit 31. As in the case of Fig. 1, the error (constituting the evaluate value) is calculated for each of the plurality of the adjust operation cases, and the trajectory adjust operation determining unit 7 selects the adjust means most superior in the evaluate value. The trajectory adjust command unit 8 transmits the selected adjust means to the individual controllers 11A to 11C of each elevator car to execute the actual operation.
Fig. 10 is a flowchart showing the process for calculating the reference interval value according to a third embodiment of the invention. First, based on the information collected by the information collector 1 of Fig. 9, the expectation value T for the one round trip time under the prevailing traffic condition is calculated (ST11) using Equation (1). $T = Σ (moving time) + Σ (stop time expectation value)$

where Σ (moving time) indicates the total sum of the moving time for the one round trip time for each floor, and Σ (stop time expectation value) the total sum of the stop time expectation value for the one round trip time for each floor. In short, the one round trip time expectation value corresponds to the average one round trip time of the elevator car under the prevailing traffic condition.
Next, the number N of cars in effective operation at the present time point is calculated (ST12). In the case where one car is out of operation in the elevator group control of four elevator cars, for example, N = 3. Based on these figures, the reference interval value Bref is calculated from Equation (2). $Bref = T / N$
The reference interval value Bref is the equal interval value for the prevailing traffic condition, or more accurately, the average equal interval value. By adjusting the interval for the forecasted trajectory of each elevator car to follow the reference interval value, the elevator cars can be controlled to equal intervals.
Fig. 11 is a functional block diagram for controlling the elevator group control system according to a fourth embodiment of the invention. In Fig. 11, the same component elements as those in Fig. 1 are designated by the same reference numerals, respectively, and not described any more. The configuration shown in Fig. 11 is different from that of Fig. 1 in that the elevator car assignment step is added for a hall call. The configuration shown in Fig. 11 has the dual function of following the reference trajectory by assignment for a hall call and following the reference trajectory by the operation control other than the assignment (called the trajectory adjust means).
The component elements of the configuration shown in Fig. 11 different from those of Fig. 1 are explained below. Each elevator hall has hall call buttons 13, 14 shown in Fig. 11, and the hall call information of these hall call buttons 13, 14 are newly collected in the information collector 1.
In a forecasted waiting time evaluating unit 50, the forecasted waiting time for provisional assignment of a generated hall call to each elevator car is calculated based on the information collected in the information collector 1. The reference trajectory computing unit 2, the forecasted trajectory computing unit 3 and the trajectory error evaluating unit 4 have the same functions as those in Fig. 1. In the case of Fig. 11, however, the forecasted trajectory for provisional assignment is also computed by the forecasted trajectory computing unit 3, and the trajectory error for the particular provisional assignment is calculated by the trajectory error evaluating unit 4. The provisional assignment is carried out for each elevator car (each of the first to third cars for the group control of three cars, for example).
In an overall assignment evaluate value calculation unit 51, an overall assignment evaluate value is calculated from the forecasted waiting time for each provisionally assigned car and the trajectory error. The overall evaluate value for provisional assignment of the first car, for example, is calculated from the forecasted waiting time of each hall call provisionally assigned to the first car and the trajectory error of the forecasted trajectory for the provisional assignment of the first car. The overall evaluate value is calculated by the weighted sum of, for example, the forecasted waiting time and the trajectory error.
An assigned elevator determining unit 52 determines an elevator car assigned a hall call based on the overall assignment evaluate value. Specifically, the forecasted waiting time and the trajectory error (degree of discrepancy between the reference trajectory and the forecasted trajectory for the assignment) are evaluated as a whole, and the assignment of the optimum elevator car is determined. An assigned elevator command unit 53 outputs an assignment command to the assigned elevator car.
As described above, the configuration shown in Fig. 11 executes the dual process of controlling the forecasted trajectory to approach the reference trajectory by the assignment of a hall call and controlling the forecasted trajectory to approach the reference trajectory by a trajectory adjust means other than assignment described with reference to Fig. 1. These two control processes are selectively determined by a trajectory adjust operation execution determining unit 54. Specifically, as long as the assignment process is not accrued, the trajectory adjust operation execution determining unit 54 retrieves the trajectory error value, compares it with a predetermined threshold value and in the case where the trajectory error value is not less than the threshold value, executes the trajectory adjust operation through the trajectory adjust means other than assignment.
As described above, according to the embodiment shown in Fig. 11, the reference trajectory following control by assignment is mainly executed, while the trajectory adjust operation by trajectory adjust means other than assignment is a complementary function.
Fig. 12 is a flowchart of the process according to the embodiment shown in Fig. 11. First, a reference trajectory for each elevator car is computed (S101), and a forecasted trajectory is computed (S102). It is then determined whether a hall call assignment process is generated or not (S103). In the case where a hall call assignment process is generated, provisional assignment is set for each elevator car, and the forecasted trajectory for assignment is computed (S104). The error between the forecasted trajectory obtained and the reference trajectory is calculated (S105). Further, the forecasted waiting time for each hall call for provisional assignment is calculated (S106). Based on the trajectory error value and the forecasted waiting time, the overall assignment evaluate value is calculated (S107), and by comparing the overall assignment evaluate value, an assigned elevator car is determined and an assignment command is output to the particular elevator car (S108).
Upon determination in step 103 that there is a period in which no hall call assignment process is generated, the error between the reference trajectory and the forecasted trajectory is calculated (S109), and it is determined whether the error is not less than a predetermined threshold value or not (S110). In the case where the error is not less than the predetermined value, the step of repeating the trajectory adjust operation setting and evaluating (S111: explained in Fig. 1) is executed. Thus, the optimum trajectory adjust means other than assignment is determined, and the operation command is output (S112).
As described above, according to this control concept, a hall call is assigned in such a manner as to approach the reference trajectory, and only in the case where the deviation of the forecasted trajectory from the reference trajectory is larger than a predetermined value during the period lacking the assignment process, the trajectory adjustment is carried out by the trajectory adjust means other than assignment described above. This combination of the dual control methods makes it possible to control the forecasted trajectory to approach the reference trajectory regardless of whether an assignment process is generated or not, thereby controlling the elevator cars to the ideal state of equal time intervals. It may happen that the trajectory change by assignment is so large that although the direction of adjustment is correct, the assignment leads to an excessive trajectory adjustment. Also in such a case, the trajectory adjust means other than assignment function as a fine adjustment, and the elevator cars are guided to the state of equal time intervals of the elevator cars in more finely detailed fashion.
Fig. 13 is a functional block diagram for controlling the elevator group control system according to a fifth embodiment of the invention. In Fig. 13, the same component elements as those in Figs. 6 and 11 are designated by the same reference numerals, respectively, and not described any more. The configuration of Fig. 13 is a development of the configuration of Fig. 11 corresponding to Fig. 1 from the configuration of Fig. 6. Specifically, the function of controlling the intervals for the forecasted trajectory to the state of equal time intervals by assignment of a hall call and the function of controlling the intervals for the forecasted trajectory to the state of equal time intervals by trajectory adjust means other than assignment are used at the same time.
The functional configuration of the embodiment shown in Fig. 13 is briefly explained. First, upon generation of an assignment process for a hall call, the forecasted waiting time evaluating unit 50 assesses the forecasted waiting time for the hall call, and the trajectory state evaluating unit 20 assesses the evaluate value of the time intervals for the forecasted trajectory upon execution of the provisional assignment for the hall call. The overall assignment evaluate value calculation unit 51 calculates the overall evaluate value based on the forecasted waiting time and the evaluate value of the time interval of the forecasted trajectory. The assigned elevator determining unit 52 determines an appropriate assigned elevator car based on the overall evaluate value, and outputs a command to the assigned elevator command unit 53. During the period when no hall call assignment process is generated, the trajectory adjust operation execution determining unit 54 determines whether the trajectory adjust operation other than assignment is to be carried out or not based on the output (evaluate value of the time interval) of the trajectory state evaluating unit 20. Upon determination that the trajectory adjust operation is to be carried out, the trajectory adjust operation explained with reference to Fig. 6 is carried out.
Fig. 14 is a flowchart for the embodiment shown in Fig. 13. In Fig. 14, the same steps as those in Fig. 12 are designated by the same reference numerals, respectively, and different steps include steps S205, S209 and S210 designated by a thick solid line. The process flow is explained below.
First, a forecasted trajectory is prepared for each elevator car (S102), and it is determined whether a hall call assignment process is generated or not (S103). Upon generation of a hall call assignment process, the elevator cars are provisionally assigned sequentially, and a forecasted trajectory with the assignment is computed (S104). Next, the evaluate value of the time interval for the forecasted trajectory with the provisional assignment is calculated (S204). Further, the forecasted waiting time of each hall call with the provisional assignment is calculated (S106). Based on the trajectory error value and the forecasted waiting time, the overall assignment evaluate value is calculated (S107), and by comparing the overall assignment evaluate value, an assigned elevator car is determined and an assignment command is output to the particular elevator car (S108).
Upon determination in step S103 that the period lacking the hall call assignment process is prevailing, the evaluate value of the time interval for the forecasted trajectory is calculated (S209), and it is determined whether this evaluate value is not less than a predetermined threshold value or not (S210). In the case where the particular evaluate value is not less than the predetermined value, the process of repeating the trajectory adjust operation setting and evaluating (S111: explained in Fig. 1) is executed, and upon determination of the optimum trajectory adjust means other than assignment, the operation command is output (S112).
The control concept shown in Fig. 14 is exactly the same as that of Fig. 12, and not explained again. Nevertheless, according to the method shown in Fig. 14, the elevator cars can be controlled to the ideal state of equal time intervals regardless of whether an assignment process is generated or not.
As described above, according to a more preferred embodiment of the invention, the trajectory of elevator operation is adjusted by the hall call assignment control and the operation control other than assignment. By appropriately utilizing these control means, a still higher effect can be achieved.
The execution of the trajectory adjust operation according to the embodiments described above only during the rush hours or in the situation involving a long waiting time is effective. Specifically, the requirement of the trajectory adjust operation is determined based on the prevailing traffic condition and the average waiting time in addition to the error between the reference trajectory and the forecasted trajectory. In the case where the error between the reference trajectory and the forecasted trajectory exceeds a predetermined value in the situation involving a long waiting time during the rush hours, for example, the trajectory adjust operation is performed. The trajectory adjust operation is intended for an auxiliary control means after all.

Claims

An elevator group control system for controlling multiple elevator cars (12A, 12B, 12C) serving a plurality of floors, comprising:
a reference trajectory computing means (2) for computing a reference trajectory indicating a reference position of each elevator car after a present time;

a forecasted trajectory computing means (3) for forecasting a position of each elevator car after the present time and computing a forecasted trajectory corresponding to the reference trajectory; and

a means (6) for adjusting selected one of a car speed and a car stop time of each elevator car and a stop position of a waiting elevator car so that the forecasted trajectory approaches the reference trajectory.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
a reference interval setting means (30) for setting a reference intervals of the elevator cars in operation; and

a means (6) for adjusting selected one of a car speed and a car stop time of each elevator car and a stop position of a waiting elevator car so that time intervals of cars approaches the reference intervals.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
a reference trajectory computing means (2) for computing a reference trajectory indicating a reference position of each elevator car after a present time;

a forecasted trajectory computing means (3) for forecasting the position of each elevator car and computing a forecasted trajectory corresponding to the reference trajectory;

an evaluating means for calculating an evaluate value of the forecasted trajectory of each elevator car with respect to the reference trajectory; and

a means (6) for adjusting selected one of a car speed and a car stop time of each elevator car and a stop position of a waiting elevator car based on the evaluate value of the evaluating means.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
a reference interval setting means for setting a reference interval of each elevator car in operation;

a forecasted trajectory computing means (3) for predicting a position of each elevator car after the present time and computing a forecasted trajectory for each elevator car;

an evaluating means for calculating an evaluate value of the forecasted trajectory for the reference intervals of each elevator; and

a means (6) for adjusting selected one of a car speed and a car stop time of each elevator car and a stop position of a waiting elevator car based on the evaluate value of the evaluating means.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
a reference trajectory computing means (2) for computing a reference trajectory indicating a reference position of each elevator car after a present time; and

a means (6) for adjusting selected one of a car speed and a car stop time of each elevator car and a stop position of a waiting elevator car so that the actual trajectory indicating the actual position of each elevator car in real time approaches the reference trajectory for each elevator.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
a forecasted trajectory computing means (3) for computing a position of each elevator car and computing a forecasted trajectory for each elevator car;

an evaluating means for evaluating a distance between the forecasted trajectories of the elevators; and

a means (6) for adjusting selected one of a car speed and a car stop time of each elevator car and the stop position of a waiting elevator car based on the evaluate value of the evaluating means.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
a forecasted trajectory computing means (3) for computing a position of each elevator car and computing a forecasted trajectory for each elevator car;

a reference interval setting means for setting the reference intervals between the elevator cars; and

a means (6) for adjusting selected one of a car speed and a car stop time of each elevator car and the stop position of a waiting elevator car so that the time interval between the forecasted trajectories of the elevator cars after a present time approaches the reference interval.
An elevator group control system according to any one of claims 1, 3 and 5,
wherein the reference trajectory includes the reference position of each elevator car for a predetermined future period.
An elevator group control system according to any one of claims 1, 3 and 5,
wherein the reference trajectory includes the reference position of each elevator car at a plurality of time points after a present time.
An elevator group control system according to any one of claims 1 to 9,
wherein the means for adjusting the car speed of the elevator cars includes a means for adjusting selected one of the car speed and the car acceleration.
An elevator group control system according to any one of claims 1 to 10,
wherein the means for adjusting the car stop time of the elevator cars includes a means for adjusting selected one of the door operation speed and the door opening time of the elevator cars and the door operation selection for a waiting elevator.
An elevator group control system according to any one of claims 2, 4 and 7,
wherein the reference interval is a reference time interval between the elevator cars.
An elevator group control system according to any one of claims 2, 4, 7 and 12, further comprising:
a forecasted trajectory computing means (3) for computing a forecasted trajectory indicating a forecasted position of each elevator during a predetermined future period;

a means for forecasting one round trip time of each elevator car based on the forecasted trajectory; and

a reference interval setting means for setting the reference interval based on the one round trip time.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
a means (6) for adjusting selected one of a car speed and a car stop time of each elevator car and the stop position of a waiting elevator in the case where the present or future relative positions of the plurality of the elevator cars meet predetermined conditions.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
an evaluation control means for forecasting the future position of each elevator car and assigning a generated hall call to an elevator car in such a manner that the intervals of the elevator cars are equalized; and

a means (6) for adjusting selected one of a car speed and a car stop time of the elevator cars other than the assigned elevator car and the stop position of a waiting elevator car.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
an evaluation control means for forecasting the future position of each elevator car and assigning a generated hall call to an elevator car in such a manner that the intervals of the elevator cars are equalized; and

a means (6) for adjusting selected one of a car speed and a car stop time of the elevator cars of other than the assigned elevator car and the stop position of a waiting elevator in such a manner as to equalize the intervals of the elevator cars during the period when a new hall call is not occurred.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
an evaluation control means for forecasting the future position of each elevator car and assigning a generated hall call to an elevator car in such a manner that the intervals of the elevator cars are equalized; and

a means (6) for adjusting selected one of a car speed and a car stop time of the elevator cars other than the assigned elevator car and the stop position of a waiting elevator car in the case where the intervals between the elevator cars are unbalanced to more than a predetermined degree during the period lacking the assignment process.
An elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising:
a reference trajectory preparation means (2) for computing a reference trajectory indicating a reference position of each elevator car within a predetermined future time;

a forecasted trajectory preparation means (3) for forecasting the position of each elevator car within a predetermined future time and computing a forecasted trajectory corresponding to the reference trajectory;

a control means for assigning a generated hall call to an elevator car in such a manner that the forecasted trajectory approaches the reference trajectory; and

a means (6) for adjusting selected one of a car speed and a car stop time of the elevator cars other than the assigned elevator car and the stop position of a waiting elevator car in such a manner as to equalize the intervals between the elevator cars which may be unbalanced to more than a predetermined degree.
A control method for an elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising the steps of:
computing (S101) a reference trajectory indicating a reference position of each elevator car after a present time;

forecasting the future position of each elevator car and computing a forecasted trajectory corresponding to the reference trajectory; and

adjusting selected one of a car speed and a car stop time of the elevator cars and the stop position of a waiting elevator car in such a manner that the forecasted trajectory approaches the reference trajectory.
A control method for an elevator group control system for controlling multiple elevator cars serving a plurality of floors, comprising the steps of:
computing (S101) a reference trajectory indicating a reference position of each elevator car within a predetermined future time;

forecasting the position of each elevator car within a predetermined future time and computing a forecasted trajectory corresponding to the reference trajectory;

assigning a generated hall call to an elevator in such a manner that the forecasted trajectory approaches the reference trajectory; and

adjusting selected one of a car speed and a car stop time of the elevator cars other than the assigned elevator car and the stop position of a waiting elevator car in such a manner as to equalize the intervals of the elevator cars which may be unbalanced to more than a predetermined degree during the period lacking an unassigned hall call.