GB2264571A

GB2264571A - Group controlled elevator system

Info

Publication number: GB2264571A
Application number: GB9303822A
Authority: GB
Inventors: Toshimitsu Tobita; Atsuya Fujino; Hiromi Inaba; Kenji Yoneda; Naofumi Nakata; Kiyoshi Shinmura
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1992-02-27
Filing date: 1993-02-25
Publication date: 1993-09-01
Anticipated expiration: 2013-02-25
Also published as: GB9303822D0; GB2264571B; JPH05238653A; KR930017800A; TW207527B; HK20796A

Abstract

A group controlled elevator system detects the concentration of multiple elevators (111, 112, 113, 114). If it exceeds a certain level, one of the elevators is restricted so as not to respond to hall calls, and a cage call destined elevator so that it is forced to separate. Overall waiting times are thereby reduced. The degree of concentration can be predicted on the basis of current cage calls and assigned hall calls, and the dispersion command issued when the predicted concentration exceeds the predetermined level. Also, the dispersion command can be suppressed if the cages will separate naturally. The arrangement is suitable for small numbers of cages and may (Fig 14) be used to coordinate just two lifts which do not have a supervisory group controller. <IMAGE>

Description

GROUP-SUPERVISORY CONTROLLED ELEVATOR SYSTEM This invention relates to the improvement of the elevator operation system which runs a plurality of elevator cages in a group-supervisory controlled manner.

The major role of the group-supervisory operation of multiple elevator cages is to offer the elevator user to have a minimal and even or uniform waiting time.

Throughout past years, there have been introduced a variety of control methods based on innovative techniques to accomplish the role.

In the past, a typical conventional control method was a hall call assignment control in which elevator cages are given variable service zones depending on their position (position and moving direction) so as to cover all floors, and when a hall call to a service zone is generated, it is assigned to an elevator cage having that service zone. In this case, to make the users' waiting time even and short, it is crucial to operate the elevator cages so that they run with intervals thereamong maintained as even as possible. To meet the demand, there were proposed elevator cage interval control methods which will be explained later.

More recently, owing to the prevalence of microcomputers, a typical elevator operation system has been designed to make a total evaluation of multiple factors at each event of hall call and select an optimal elevator cage for it based on an instantaneous process of the computer, and this sophisticated groupsupervisory controlled elevator system has been applied particularly to large-scale buildings.

This system uses a total evaluation formula which involves many concepts including the reduction of mean wait time and the prevention of long-wait calls, and, on the other hand, positional relation among the elevator cages is not much concern.

The.following describes examples of the elevator cage interval control carried out by the abovementioned conventional group-supervisory controlled elevator systems.

Control schemes for preventing the concentration of cages, which is called overlapped" state, by limiting responses to hall calls are described in JP-B-51-15291, JP-B-53-174 and JP-B-54-16291, for example. According to the technique disclosed in JP-B51-15291, the elevator operation is scheduled in advance and, if the operation of an elevator goes out of the schedule, it is operated to make a limited response to hall calls. According to the technique disclosed in JP B-53-174, elevator cages are operated to make limited responses to hall calls so that the numbers of stops of all elevator cages become even.According to the technique disclosed in JP-B-54-16291, an elevator cage is responsive to hall calls, with its position signal being modified to indicate an advanced position depending on the distance between it and other elevator cages and the number of calls for which it stops.

Control schemes, with the condition of restriction of hall calls being different from the above-mentioned ones, are described in JP-B-51-15298 and JP-B-51-17778. The former technique is designed to limit the assignment of hall calls to a front-running elevator cage when the interval from another elevator decreases so as to maintain constant intervals among the group of elevator cages. Specific methods of such hall call restriction include the restriction of calls from a certain range of position beginning at the position indicated by the position signal so that the elevator position is apparently advanced, and the restriction of responses to hall calls until certain conditions are met. The latter technique is intended to perform more practical control by taking consideration of the number of elevator cages into the condition of restriction of hall call assignment.Reference may be further made to USP 4,947,965 for a related group control method.

Although the hall call assignment control technique intended to assign a hall call to an optimal elevator cage based on the total evaluation value is adopted particularly in sophisticated group-supervisory controlled elevator systems for large-scale buildings, there is still a demand of upgrading the performance of elevator operation systems for small and medium-scale buildings having only a few elevator cages.

It was revealed in the study of elevator operation that the application of the above-mentioned hall call assignment control technique based on the total evaluation value to an elevator operation system including only two to three elevator cages does not attain the expected enhancement of performance.

It was also revealed that even the additional introduction of the conventional elevator cage interval control offers little effectiveness irrespective of the number of elevator cages.

An object of this invention is to provide a group-supervisory controlled elevator system with improved elevator cage interval control capable of enhancing the serviceability for the users.

According to a preferred aspect of this invention, the elevator operation system includes means for moving compulsively an arbitrary elevator cage in response to a certain state among multiple elevator cages.

In a preferred form of this invention, when multiple elevator cages have come close together, an arbitrary elevator cage is given a cage call (destination call) destined to such a position that the positional interval among the elevator cages becomes even, and the elevator cage of concern is restricted so as not to make response to hall calls.

Based on the above-mentioned arrangement of this invention, when multiple elevator cages have come close or are about to come close, an arbitrary elevator cage is forced to move from the position of close state to a distant position so that an effective interval control for the multiple elevator cages are attained, whereby elevator service is made even.

According to one form of this invention, one elevator cage is not only restricted so as not to make response to hall calls, but it can be moved from a position of concentrated elevator cages to a distant position promptly, whereby an effective interval control can be executed.

It seems that the elevator operation systems of recent years designed to assign a hall call to an optimal elevator cage based on the total evaluation value does not consider seriously the gathering (concentration) of multiple elevator cages, as mentioned previously. They perform the group-supervisory controlled operation for four or more elevator cages by selecting an optimal elevator cage through the evaluation in terms of several viewpoints at each instance of call event, thereby attaining the intended performance.

The inventors of the present invention conducted a simulation in which such assignment technique was applied to an elevator system having only two to three cages. This simulation however revealed that once multiple elevator cages come close together (will be termed concentration), i.e., the emergence of the "overlapped" state, during the state of traffic congestion, it does not dissolve easily and long-wait calls are liable to occur0 The total evaluation formula naturally includes the parameter of preventing the concentration of elevator cages. However, as it is obvious from the conventional elevator cage interval control, any of these systems operating by being dependent on the generation of hall call does not respond quickly to the situation and therefore cannot prevent the concentration effectively.

Even in the group-supervisory controlled operation of four or more elevators, when hall calls to a specific floor occur frequently in such time bands as the morning and lunch time, the elevator cage interval control which is dependent on hall call generation is less effective.

For dealing with the above-mentioned situation, when multiple elevator cages have concentrated or the concentration is anticipated, arbitrary one of these elevator cages is forced to move to a position which is distant from the position of concentration. As one example of operation, the designated elevator is prohibited to respond to hall calls and a cage call (destination call) to a distant position is issued to it so that it is forced to move. In the case of the operation involving two elevators, it is desirable to move the designated elevator to the position which is "opposite" in position and direction to the position of concentration.In the case of a 10-floor building, if concentration occurs in the upward direction at the third floor, the opposite (counter) position and direction are the down-facing eighth floor, and accordingly a cage call destined to the eighth floor should be generated.

Consequently, the concentration of elevator cages dissolves promptly without being affected by the situation of hall call generation, and the elevator cage waiting time for hall calls is made even.

Fig. 1 is a block diagram of the overall group-supervisory controlled elevator operation system based on an embodiment of this invention.

Figs. 2A - 2E are diagrams explaining the "overlapped" (concentration) state and the effectiveness of dispersion based on an embodiment of this invention.

Figs. 3A - 3F are diagrams explaining an embodiment of the method of concentration judgement.

Fig. 4 is a flowchart of an embodiment of the issuance of a dispersion control (forced movement) command.

Fig. 5 is a flowchart of an embodiment of the calculation of the concentration degree.

Fig. 6 is a flowchart of an embodiment of operation until the forced movement takes place after the reception of the dispersion control command.

Fig. 7 is a diagram of an embodiment of the issuance of the dispersion control command of the case where the concentration degree of the future is taken into account.

Fig. 8 is a flowchart of an embodiment of the case where the dispersion execution assessment value is taken into account.

Fig. 9 is a flowchart of an embodiment of the calculation of the execution assessment value.

Fig. 10 is a block diagram of the overall arrangement of the group-supervisory controlled elevator operation system based on another embodiment of this invention which performs the dispersion control based on the prediction of the "overlapped" state.

Fig. 11 is a flowchart of an embodiment of the issuance of a dispersion control command of the case of the prediction of the "overlapped" state.

Fig. 12 is a flowchart of an embodiment of the case where the concentration degree of the future is taken into account for the prediction of the "overlapped" state.

Fig. 13 is a flowchart of an embodiment of the case where a dispersion execution evaluation value is taken into account for the prediction of the "overlapped" state.

Fig. 14 is a block diagram of the overall arrangement of the elevator operation system based on another embodiment of this invention of the case where the group-supervisory controller is absent.

The following describes embodiments of this invention with reference to the drawings.

Fig. 1 is a block diagram of the overall arrangement of this invention. Information produced by hall call buttons 101-lOn is collected by a hall call collection means 31 in a group-supervisory controller 3 through a hall call transmission path 2, and then sent to an assignment controller 32. Information of cage call buttons 41-44 is collected in a cage call collection means 33 through a cage call transmission path 5, and then sent to the assignment controller 32. The assignment controller 32 receives cage position signals of all cages from cage controllers 61-64 over a transmission line 7, and determines elevator cages to be used for hall calls from the cage position signals, cage call signals and hall call signals, and sends assignment signals over the transmission line 7.The cage controllers 61-64 control winches 91-94 which are driven by motors 81-84 to move cages 111-114 so that services for the hall calls and cage calls are implemented.

Indicated by 121-124 are counter weights. A time/ spatial position measuring means 34 receives hall call signals and cage call signals from the hall call collection means 31 and cage call collection means 33 and further receives cage position signals from the assignment controller 32, and measures the positions in terms of time and space of all elevator cages. A concentration degree calculation means 35 receives the time/spatial position signals of all elevator cages from the time/spatial position measuring means 34, and evaluates the degree of concentration of elevator cages from the time/spatial positions.A dispersion command issuance means 36 tests whether or not the degree of concentration of elevator cages evaluated by the concentration degree calculation means 35 has reached a predetermined value, and if it is found to reach the threshold, the command issuance means sends a dispersion command to the assignment controller 32, which then selects an optimal elevator cage based on the hall call information, cage call information and cage positions, and it causes the elevator cage to move to a position distant from other elevator cages irrespective of the presence or absence of hall calls thereby to dissolve the state of concentration called "overlapped" state.

Figs. 2A - 2E are diagrams used to explain the "overlapped" state of the case of only two elevator cages for the purpose of simplicity. Shown by Figs. 2A and 2B are explanatory diagrams of the "overlapped" state, Fig. 2C is an operation diagram of a satisfactory operation, Fig. 2D is an operation diagram at the occurrence of the "overlapped" state, and Fig. 2E is a diagram showing the effectiveness of forced separation at the occurrence of the "overlapped" state. The "overlapped" state occurs frequently during a traffic congestion when many hall calls are generated. When elevator cages are spaced out from the beginning as shown in Fig. 2B, each elevator cage is operated with a virtually equal time spacing in the range from the current position to the position of a front-running elevator even in the case of the assignment control.

However, once the "overlapped" state emerges, a frontrunning elevator is passed by the following elevator during the service of an immediate hall call, and the passing elevator takes a service for the next hall call.

This operation is repeated, and therefore once the "overlapped" state has occur, this state will continue for a while. The operation line of an elevator cage A is shown by 13A, and that of an elevator cage B is shown by 13B. The "overlapped" state is intended to be prevented by causing an elevator cage, to which a hall call is already assigned, to be liable to also accept another hall call of the position near the first call.

However, since such scheme does not address the problem of the "overlapped" state actively, a delay will result.

In addition, frequent passes against hall calls will invite user's dissatisfaction when this scheme is practiced for an elevator system equipped with an indicator. In dealing with this matter, it is possible to alleviate the deterioration of operational efficiency due to the "overlapped" state by forcing the elevator cages to separate as soon as the "overlapped" state is detected, as shown in Fig. 2D. Even for the elevator system with the indicator, the "overlapped" will not recur soon after the elevators have been brought to the maximum separation, and accordingly the user's dissatisfaction due to frequent passes against hall calls will be alleviated.Issuance of the dispersion control command is not much frequent, and by displaying "Express" for example at the forced separation using the dispersion control command, uneasiness felt by the users due to unusual elevator operation can be alleviated.

Figs. 3A - 3F are diagram used to explain an example of the method of calculating the degree of concentration by the concentration degree calculation means Since the first through third elevator cages go up and down as shown in Figs. 3A, 3B and 3C, they have the attribute of direction as well as position. The positions of the elevator cages are calculated by assuming that they go around up and down as shown by Figs. 3D, 3E and 3F. The concentration degree of the case when the elevator cages are located at the same position and have the same direction, as shown by Figs.

3A and 3D, is called here 100% concentration. In this case, a floor where all elevator cages have just passed do not have service until an elevator cage comes after it goes around up and down, and therefore it has the longest waiting time. In the cases of Figs. 3B and 3E, two elevator cages come close and another elevator cage is located at the position opposite to the position of concentration (counter position), and this is an example of 50% concentration. The longest waiting time is half the cases of Figs. 3A and 3D, and the distance is also half. In the cases of Figs. 3C and 3F, three elevator cages have the positional relation of equal interval, and this is the case of 0% concentration. A hall call generated when the elevator cages have equal separation in terms of time and space has the shortest expected waiting time.The relation among concentration degree, distance between elevator cages, expected waiting time and predicted maximum waiting time is obtained in advance through interpolation operation, such as, for example, proportional allotment, based on the time spacing between elevator cages, distance between elevator cages, expected value of waiting time, and predicted maximum waiting time of the above-mentioned three state. Based on the thus obtained relation, the concentration degree calculation means 35 of Fig. 1 calculates the degree of concentration.

Fig. 4 is a flowchart of the issuance of the dispersion control command. Initially, the time/spatial position measuring means 34 measures the positions in terms of time and space of all elevator cages (step 401), and next the concentration degree calculation means 35 evaluates the degree of concentration of elevator cages based on these time/spatial positions, as explained in connection with Fig. 3 (step 402).

Subsequently, the dispersion command issuance means 36 tests whether or not the concentration degree exceeds a predetermined value (step 403), and if it is found excessive, the command issuance means 36 sends the dispersion control command to the assignment controller 32 (step 404). According to this embodiment, elevator cages are forced to disperse and the deterioration of elevator operation efficiency caused by the "overlapped" state can easily be prevented.

Fig. 5 is a flowchart showing an example of the calculation of concentration degree (step 402). The concentration degree calculation means 35 receives the time position or spatial position measured by the time/spatial position measuring means 34 (step 402-1).

Next, it selects the largest of distances L12, L23, Lnl among the elevator cages (step 402-2).

It may be evaluated by formula 1 below. In formula 1, Ls is the length measured from the highest floor to the lowest floor. Ls is multiplied by two and the result is subtracted by Le which is the length of the equal intervals of elevator cages evaluated by dividing the one round length of an elevator cage by the number of the elevator cages, thereby obtaining (2Ls Toe), and the maximum elevator cage interval value Lmax subtracted by the Le is divided by the (2Ls-Le). This is formulated as follows.

(Lmax-Le)/(2Ls-Le) ... (1) This formula is applied to Fig. 3.

In the cases of Figs. 3A and 3D, the first and second elevator cages have a zero interval, the second and third elevator cages also have a zero interval, and the third and first elevator cages have the interval of 2Ls which is the one round length. Since the maximum interval length Lmax is equal to 2Ls, the formula 1 evaluates the degree of concentration to be 1, i.e., 100%. In the cases of Figs. 3C and 3F, all elevator cages have an equal interval of 2Ls/3, and the maximum interval Lmax is equal to 2Ls/3, and it is equal to Le.

Accordingly, the formula 1 reveals no concentration in these cases, and it is consistent with the description of Fig. 3. In the cases of Figs. 3B and 3E, the first and second elevator cages have a zero interval, and there is an interval of Ls between the second and third elevator cages and also between the third and first elevator cages, with the maximum interval Lmax being Ls.

Accordingly, the calculated concentration degree based on the formula 1 is 0.25, i.e., 25%, and it is not consistent with 50% described in Fig. 3. However, this inconsistency results from the setting of the predetermined value (reference value) in step 403 of Fig. 4, and it does not matter. It can be understood that the cases of Figs. 3B and 3F have a 25% concentration inherently.

The foregoing calculation of concentration degree is carried out in step 402-3 in Fig. 5.

The method of evaluating the concentration degree is not limited to the foregoing one, but another evaluation method makes reference to a concentration degree calculation table which is created such that the relation between the maximum value of elevator cage distances and the degree of concentration is as shown in Fig. 3, in place of the steps 402-2 and 402-3 in Fig. 5.

Still another method calculates the squared mean value of the elevator cage distances L12, L23, .., Lnl subtracted by Le, and divides the result by 2Ls. This is formulated as follows.

{(Ll2-Le)2+(L23-Le)2+..+(Lnl-Le)2}/2Ls ... (2) The distance mentioned here is either the spatial distance that stands for the physical position, or the time distance that stands for the time spacing between the elevators. In the case of calculating the concentration degree based on the time distance, the time length expended by the elevator cage to go around from top to bottom is used in place of 2Ls.

For calculating the predicted concentration, the predicted position is used in place of the current position for the position of each elevator cage.

Fig. 6 is a detailed flowchart of an embodiment of the dispersion control command issuance which is step 404 of Fig. 4.

Initially, the dispersion control command is received from the dispersion control command issuance means 36 in step 404-1, and a dispersed position is derived in steps 404-2 through 404-4. In the next step 404-5, an elevator cage which is forced to disperse is determined selectively, and in step 404-6 one of the car controllers 61, 62, 63 or 64 for the selected elevator cage is operated to generate a cage call so that the elevator cage moves to the dispersed position.

In the next step 404-7, among hall calls which are already assigned to the elevator cage, assignments of hall calls destined to floors up to the destination floor of the automatically issued cage call are cancelled, and these calls are assigned to other elevators cage.

The steps 404-2 through 404-5 will be explained in more detail. In step 404-2, the distance from each elevator cage to the central position of the elevator cage group is calculated. Next, the position which is opposite to the central position is calculated (step 404-3). Finally, a floor which is nearest to the opposite position is found (step 404-4).

Consequently, the destination floor to which the elevator cage is forced to move is determined. In the next step 404-5, an elevator cage which is nearest to the central position of the elevator cage group is selected.

This embodiment is effective in that the degree of concentration can be lowered to a large extent by a single issuance of the dispersion command. Instead of selecting an elevator cage which is nearest to the central position of the elevator cage group in the foregoing step 404-5, an alternative manner is to select an elevator cage which has the smallest number of assigned calls until it reaches the destination floor of forced movement based on the process of the step 404-4, or these two manners may be combined. As a manner of determining the destination floor, in place of the step 404-4, the floor may be an end floor near the opposite position of the current elevator cage group position or it may be the reference floor.Although the embodiment described above is the case of generating a cage call destined to the forced movement position, it is sufficient to move the elevator cage to the determined position without generating a cage call, and in this case it is not necessary to open the elevator door and therefore it is not necessary for the destination position to be coincident with a floor position. The predetermined value used to determine the issuance of the dispersion command is selected in the range from 70% to 100% of concentration, although it varies depending on the manner of calculation of the concentration degree.

The rule of determination of a floor for dispersion can be modified as follows. These are; (1) an end floor nearest to the opposite position of the elevator cage concentration position, (2) a floor located at the same distance from the top and end of the concentration position, and (3) the highest floor or the reference floor whichever is farther from the concentration position. The rule of selection of an elevator cage which is forced to disperse can be modified as follows. These are: (1) an elevator cage which has no assignment of call, (2) an elevator cage located at an end floor, (3) an elevator cage which is going to an end floor, (4) an.elevator cage which arrives at an end floor as the second one, and (5) an elevator cage which is located at the middle of the elevator cage group.An alternative manner is to calculate the dispersion execution evaluation value for each elevator cage and designate the elevator cage with the smallest evaluation value.

Fig. 7 is a flowchart of the dispersion control command issuance of the case where the predicted concentration degree is taken into account. Steps 401 through 403 are identical to those of Fig. 4. If the concentration degree is in excess of the predetermined value, the concentration calculation means 35 calculates the predicted concentration degree based on the current cage calls and assigned hall calls (step 701). Next, the dispersion control command issuance means 36 tests whether or not the predicted concentration degree exceeds the predetermined value (step 702), and issues a dispersion control command in the excessive case (step 404). According to this embodiment, the issuance of the dispersion control command can be suppressed when elevator cages disperse naturally through the generation of cage calls and hall calls, and therefore more practical operation can be accomplished.

Fig. 8 is a flowchart of the dispersion control command issuance of the case where the dispersion execution evaluation value is taken into account.

Steps 401 through 403 are identical to those of Fig. 4.

If the concentration degree is in excess of the predetermined value, the dispersion control command issuance means 36 calculates the dispersion execution evaluation value which comprehends the predicted concentration, the change in the waiting time at each floor depending on the execution of the dispersion control command and the user's dissatisfaction due to the switching to the express operation (step 801). In the next step 802, it is tested whether the dispersion execution evaluation value is in excess of the predetermined value, and a dispersion control command is issued in the excessive case (step 404). According to this embodiment, it is possible to execute the dispersion control command through the total judgement on the influence of the execution.

The dispersion execution evaluation value is calculated from the number of hall calls generated, the separation of elevator cages after the elevator cage movement, the time expended until the movement takes place, the amount of energy consumed for the movement, and the number of hall calls which are ignored.

Fig. 9 is a flowchart showing an example of the method of calculating the execution evaluation value in step 801 in Fig. 8. Initially, the dispersion control command issuance means 36 calculates the predicted concentration degree Dp after the issuance of the dispersion command (step 901). Next, the increase Dt of waiting time resulting from the dispersion command issuance is evaluated (step 902). In the case of an elevator system equipped with the indicator, the numbers of hall calls Dn for which the elevator cage in express operation due to the dispersion command passes are evaluated (step 903). Next, the resulting values are multiplied by respective weighting factors al, a2 and a3 and then summed thereby to obtain the execution evaluation value Dd (step 904). This is formulated as follows.

Execution evaluation value Dd = alDp+a2Dt+a3Dn ... (3) Fig. 10 shows an embodiment which is intended to prevent the occurrence of elevator concentration, i.e., "overlapped" state, by dispersing the elevator cages in advance when the occurrence of the "overlapped" state is anticipated, in addition to the actual event of the "overlapped" state. Signals of special hall call buttons 141, 142, .., 14n and signals of special cage call buttons 151-154 provided for the wheel chair user are sent to the hall call collection means 31 and cage call collection means 33, respectively, and these means add information regarding usual calls to the information regarding special calls and sends the result to a judgement means 37 for the number of equivalently grouped cages which are supervised by the supervisory controller.The judgement means 37 receives a maintenance operation command and other command from a maintenance operation command unit 16, -and further receives positional information of all elevator cages from the assignment controller 32. The judge means 37 detects based on the information the reduction in the number of elevator cages under group control due to the response to a special call or due to the maintenance activity and the reduction in the number of assignable elevators due to the usage of some elevator cages for the express zone or specified floor, and sends a car reduction signal to the dispersion control command issuance means 36. On receiving the car reduction signal, the command issuance means 36 judges in consideration of the concentration degree and the like as to whether or not the signal is to be sent to the assignment controller 32. The remaining portion is identical to Fig. 1. Although the special call is the wheel chair call as an example of the above explanation, it may include the VIP call and other special calls.

Although the signal entered by an external facility is for the maintenance operation as an example of the above explanation, it, may include signals which cause the reduction in the number of elevator cages under group control, such as the signals of reservation, express operation, halt for energy saving, and scheduled operation entered by the building management facility or the like.

Fig. 11, Fig. 12 and Fig. 13 are flowcharts of the case where the dispersion control command is issued also when the "overlapped" state is anticipated. The judgement means 37 calculates the number of equivalently grouped elevator cages (step 201), and it issues the dispersion control command when the number of equivalently grouped elevator cages reduces (step 202). The remaining portion is identical to Fig. 4, Fig. 7 and Fig. 8. The embodiment of Fig. 11 is simple in structure and it can be practiced easily. The embodiment of Fig. 12 is capable of suppressing the issuance of the dispersion control command at the time of natural dispersion, and therefore it can be operated more practically. The embodiment of Fig. 13 can be practiced through the total evaluation of the influence of the dispersion control command when it is executed.

Fig. 12 shows an embodiment of the case where no group-supervisory controller is used. Shown here is the system including two elevator cages 111 and 112.

The system has independent cage call transmission paths 51 and 52 used for the first and second cages.

Individual car controllers 61 and 62 communicate with each other to indicate the current position of each cage through an inter-controller signal line 17. The remaining arrangement is identical to Fig. 1.

The following explains this embodiment, looking at the first cage. The second cage 112 approaches the first cage 111 from behind it, and.when their distance becomes a predetermined value, the car controller 61 operates on the motor 81 so that the first cage is forced to move to a position which is distant from the second cage. In this case, the elevator cage which is forced to move is determined in advance. Accordingly, unprofitable movement of both elevator cages at the same time for dispersion can be avoided. In case the elevator cage of forced movement is not determined in advance, it is desirable to make a rule of designating the forced-moving elevator to be either the approaching one or approached one.

According to the foregoing embodiments of this invention, the degree of concentration of elevator cages is examined at each moment, and an elevator cage is forced to separate on detecting the state of concentration, whereby the concentration state can be dissolved promptly, service can be made even, and waiting time can be reduced. Even in case the running order of elevator cages varies in the group operation based on the assignment control, the elevator operation can be controlled properly. In the case of an anticipated concentration or overlapped state prior to an actual overlapped state, the elevator cages are dispersed in advance based on the judgement, whereby the "overlapped" state can be prevented.

This invention can offer the group-supervisory controlled elevator system which is enhanced in the quality of user service through the effective interval control of multiple elevator cages.

Claims

CLAIMS:

1. A group-supervisory controlled elevator system including a plurality of elevator cages and operating to assign a generated hall call to a specific elevator cage, said system further including means for moving compulsively an arbitrary elevator cage in response to a certain operational state of the elevator cages.

2. A group-supervisory controlled elevator system according to claim 1, wherein said compulsive moving means comprises means for selecting an elevator cage so that an elevator cage having a less number of passed hall calls which are already assigned is moved compulsively.

3. A group-supervisory controlled elevator system according to claim 1, wherein said compulsive moving means comprises means for moving an elevator cage to a position which is distant from other elevator cages.

4. group-supervisory controlled elevator system according to claim 1, wherein said certain operational state is that the interval among the elevator cages is smaller than a predetermined value.

5. A group-supervisory controlled elevator system including a plurality of elevator cages installed in parallel, said system further including means for moving compulsively an arbitrary elevator cage so that the elevator cages have a positional relation of a virtually equal distance.

6. A group-supervisory controlled elevator system including a plurality of elevator cages installed in parallel in a building, said system further including means of detecting the approximation of one elevator cage to another elevator cage, and means for moving said one elevator cage in response to the operation of said detection means.

7. A group-supervisory controlled elevator system including a plurality of elevator cages installed in parallel in a building, said system further including means for moving the elevator cages so that each elevator cage has a predetermined positional relation with other elevator cages.

8. A group-supervisory controlled elevator system including three or more elevator cages, said system further including means for detecting a predetermined approximation among the elevator cages, and dispersion command means which operates in response to the operation of said detection means.

9. A group-supervisory controlled elevator system including means for moving compulsively an arbitrary elevator cage, and means for displaying a message in elevator halls indicative of out-of-service of the elevator cage which is being moved compulsively.

10. A group-supervisory controlled elevator system including two elevator cages, said system further including means for detecting a predetermined approximation among the elevator cages, and means for moving one elevator cage to the position opposite to the current position thereof in response to the operation of said detection means.

11. A group-supervisory controlled elevator system which controls the operation of a plurality of elevator cages, said system including means for predicting the concentration of elevator cages, and means for moving compulsively an arbitrary elevator cage in response to the output of said prediction means.

12. A group-supervisory controlled elevator system according to claim 11, wherein said concentration prediction means is responsive to either a decrease in the number of elevator cages under control or the generation of a hall call destined to a floor which has no service of any elevator.

13. A group-supervisory controlled elevator system including a plurality of elevator cages, said system further including means for detecting a predetermined approximation among the elevator cages, means for restricting, in response to the operation of said detection means, an elevator cage from responding to a hall call, and means for generating for said elevator cage a cage call originating from a position opposite to the elevator group.

14. A group-supervisory controlled elevator system according to any one of the preceding claims in which said means for moving said arbitrary elevator cage is arranged to prevent said generated call being assigned to said arbitrary elevator cage.

15. A group-supervisory controlled elevator system substantially as herein described with reference to and as illustrated in Figs. 1 to 9, Figs. 10 to 13 or Fig. 14 of the accompanying drawings.