GB2077954A - Lift control system - Google Patents

Abstract

An operation control system for managing and controlling operations of lift cars (EL1, EL2) driven in parallel includes a plurality of car control apparatus (L1, L2) each adapted to control individually an associated car. Each of the car control apparatus (L1, L2) includes an input/output unit (ACIA) for exchanging information about positions and travel directions of the cars with the other car control apparatus, and a supervisory control unit (L, SM) for controlling operation of the associated car in conjunction with the other cars on the basis of the information received. <IMAGE>

Description

SPECIFICATION Control system for plural elevator cars The present invention relates in general to an elevator control system and in particular concerns a system for managing and controlling with the aid of a computer a plurality of elevator cars which are driven in parallel.

As an elevator control system of the type described above, there has hitherto been known an elevator car operation control system for a plurality of elevator cars driven in parallel which system includes car control apparatus each provided in association with a corresponding one of the elevator cars for controlling operation only of the associated or corresponding car and a group supervising control apparatus for collectively supervising or managing all the car control apparatus, as is disclosed in U.S. Patents 3,443,668 and 3,851,733. The prior art control system suffers serious deficiency in that when a failure occurs in the group supervising control apparatus, the elevator cars will possibly be disenabled to perform services for hall calls, leading eventually to the shutdown of the substantially whole elevator system.To deal with such difficulty, it is common in practice to provide the control system in duplication or threefold. Moreover, although the provision of the group supervising control system is desirable in the case of a large scale elevator system where a large number of elevator cars have to be controlled under supervision or a great number of floors have to be serviced, it is not preferred from the economical viewpoint to provide independently the group supervising control apparatus in the case of a small scale elevator system in which the number of cars is less than four or the number of floors to be serviced is less than ten, for example.

As an attempt to solve the problem mentioned above, there has been proposed an elevator control system for controlling a number of cars driven in parallel which system includes a number of car control apparatus each provided in association with a corresponding one of the elevator cars, wherein one of the car control apparatus is imparted with a group supervising control function, as is disclosed in U.S. Patent 4,114,730.

When malfunction or failure occurs in the supervising control function, the individual car control apparatus perform the operation control for the associated elevator cars independently from the group supervising control. Certainly, this control system is also advantageous in respect of the expenditure. However, there are numerous problems to be solved in this control system. First, since the group supervising control function is imparted only to a given one of the car control apparatus, there arise differences in hardware as well as software structure among the car control apparatus, which are of course undesirable in respect of standardization, production control, exchangeability and maintenance of the car control apparatus.Second, when the car control apparatus imparted with the group supervising control function or a power supply source undergoes failure, then the group supervising control function will be lost, to involve a remarkably degraded operation efficiency and reliability. For example, two elevator cars may respond to a single hall call. To evade the above shortcomings, it is conceivableto impart the group supervising control function to each of the car control apparatus to thereby provide the group supervising control in duplication or threefold. However, such measures mean necessarily an introlerably expensive and complicated system, while the car controller as well as the group supervising controller can not process the service requests with a satisfactorily quick response.

Accordingly, an object of the invention is to provide an elevator operation control system for managing and controlling a plurality of elevator cars driven in parallel which system is made immune to the drawbacks of the hitherto known control system by imparting to each of the car control apparatus the function to supervise and control the associated cars in conjunction with positions and travel direction of the other cars.

In view of the above and other objects of the invention which will become more apparent as description proceeds, it is proposed according to an aspect of the invention an elevator operator control system, comprising a plurality of elevator cars adapted to be operated in parallel for serving a plurality of floors of a building and a plurality of car control apparatus each provided in association with a corresponding one of the elevator cars for controlling individually operation of the associated elevator car, wherein each of the car control apparatus includes input/output means for transmitting informations concerning at least position and travel direction of the associated car to the other car control apparatus associated with the other elevator cars and receiving informations concerning at least positions and travel directions of the other elevator cars from the other car control apparatus, and a supervisory control unit for controlling operation of the associated elevator car in consideration of the informations concerning the positions and the travel directions of the other elevator cars.

With the terms "supervising control" or "supervisory control" as used herein, it is intended to mean the controlling of plural cars in mutual conjunction with one another and encompasses service allocation control for the hall calls, a distributed stand-by control in the case where no service calls are issued, a regulated operation control performed upon earthquake, fire, power service interruption and the like event, patterned operation controls effective at predetermined periods and so forth.

The above and other objects, novel features and advantages of the present invention will become more apparent from the description of exemplary embodiments of the invention. The description makes reference to the accompanying drawings, in which: Figure 1 shows schematically a general arrangement of an elevator control system according to the teaching of the invention; Figure 2 shows in a block diagram a hardware structure of a microcomputer employed in carrying out the invention; Figures 3 and 4 illustrate processing algorithms on the basis of which the invention may be implemented; Figure shows an arrangement of a table of data used in the supervisory control carried out according to an embodiment of the invention;; Figure 6 shows a flow chart to illustrate a supervisory control program used for controlling the associated elevator car in conjunction with operations of the other cars; Figures 7to 13 show flow charts to illustrate details of important sub-programs included in the supervisory control program shown in Figure 6; Figure 14 shows a flow chart to illustrate an interrupt program for processing acceleration and slow-down commands for the associated elevator car; Figure 15 illustrates in a flow chart example of an associated car operation controlling program which is activated for interrupt at a predetermined period; and Figure 16 schematically illustrates another example of the supervisory control according to the invention.

Now, the invention will be elucidated in more detail in conjunction with the exemplary embodiments thereof by referring to the accompanying drawings. In the following, the supervisory control functions will be described primarily in conjunction with the processings of services for the hall calls with the aid of a 8-bit general purpose microcomputer such as one commercially available from Hitachi Ltd. of Japan under the trade name "HMCS-6800", by way of example only. Further, to simplify the description, the invention will be described as applied to an eight landing structure served by two elevator cars which are subjected to the supervisory control.

Figure 1 schematically illustrates a general arrangement of an elevator control system according to an embodiment of the invention.

A block H referred to as the hall call signalling unit represents in a set all the hall call button switches provided at individual floors. The hall call signals as produced are supplied to car control apparatus L1 and L2 and stored in respective memories through associated parallel interface adapters PIA. On the other hand, data exchange between the car control apparatus Lr and L2 iS performed through asynchronous interface adapter ACIA. Data as exchanged includes at least those informations which are required for the supervisory controls inherent to the individual cars EL1 and EL2, respectively, wherein data for the travel direction and the position of the cars are indispensable. Further, data concerning operation modes such as exclusive or independent operation mode, for example, may be included, as occasion requires.In this connection, it should be mentioned that the data for the car position indicates a position which is ahead of the actual position of the running car so that it can respond to a stop command smoothly. Such indication or designation of the advance car position is effected in a well known manner The data exchanges are periodically performed through the asynchronous interface adaptors ACIA at a predetermined time interval, whereby data as exchanged are stored in the memories of the associated microcomputers, respectively.

The entry means for inputting the data required for operations of the car as described above includes car button switches CA provided in the individual cars for registrating floors at which the car is to be stopped, door condition detecting switch for detecting the opened or closed state of the car and or floor door, safety limit switches for detecting up and down travel limits of the car and the like. These data are stored in the car memory through the parallel interface adaptor circuit PIA. On the other hand, data for commanding the opening and closing of the car and/or floor door as well as data required for driving the car, lighting of display lamps in response to the car calls and the hall calls and so forth are delivered through the parallel interface adaptor circuit PIA.

A salient feature of this invention resides in that the microcomputer destined for implementing the control functions required for the controls of operations of the car with which the said microcomputer is associated is additionally imparted with a supervisory control capability which allows the microcomputer to perform the supervisory control function SM for controlling operation of the associated car in consideration of the operating states of the other car. Accordingly, the car control units of all the individual cars are utterly identical with each other in respect of hardware and software realizations.

Figure 2 schematically illustrates a hardware configuration of a car control apparatus L, for the car No. A which can be realized by using a microcomputer. It goes without saying that the other car control apparatus L2 iS of a similar hardware configuration.

The heart of the car control apparatus L1 is a main processing unit MPU destined for executing arithmetic operations. Connected through a control bus C, an address bus A and a data bus D to the main processing unit MPU are a random access memory RAM for storing data temporarily, a read-only memory ROM for storing control programs which will be described hereinafter, and the parallel interface adaptor circuit PIA and the asynchronous interface adaptor circuit ACIAfor allowing data exchange with the external system outlined above. These components perform operations in accordance with the instructions issued from the main processing unit MPU, wherein importance is set on the sequential processing procedures, that is, the control program.

In the following, description will be made on the procedure for servicing the hall calls or, to say in other words, the arithmetic or logical processing program for serving the hall calls which is important above all in the supervisory control.

It should first be mentioned that the arithmetic processing program for servicing the hall calls is allotted with a lower priority level for execution as compared with a car operation control program described hereinafter, in view of the fact that the car operation control program for controlling the opening and closing of door, acceleration and deceleration or slow-down of car and the like is determinant for the security precision of the landing level, comfortableness in ride or the like and for this reason has to be executed rapidly with a high priority. In contrast, the processing of the hall call to be serviced has lesser influence to the important performances described above and thus need not be performed with a quick response.

Before entering into description of the arithmetic processing program for the hall call service, algorithm of the arithmetic operation will briefly be elucidated.

In Figure 3, there are illustrated a procedure for processing the hall calls. Since an elevator cage or car is operated in two direction, i.e. up-direction UP and down-direction DN, the floors serviced by the elevator car may be considered as being arrayed in a loop, as illustrated in Figure 3 at (a). The corresponding data pattern for the microcomputer is organized in such a manner as illustrated in Figure 3 at (b). As can be seen from this figure, the floors to be serviced in the up-direction and those serviced in the down-direction are serially stacked. More specifically, a floor table of two bytes (on the assumption that the number of floors is eight) is reserved in the memory, whereby the first byte is allotted to the floor services in the up-direction UP with the second byte being correspondingly assigned to the floor services DN in the down-direction.In this connection, attention should be paid to the fact that in the case of the floor service in the down-direction DN, the sequential order of the floor identifying numbers of the building is reversed.

Figure 4 shows a chart for illustrating algorithm of arithmetic operations for processing the hall calls.

It is now assumed that the position PA of the one car labelled with a leter A corresponds to the fourth floor in the course of running in the up-direction, while the position P8 of the other car denoted by a letter B corresponds to the sixth floor in the course of travel in the down-direction. These situations may be given by expressions PA = 4U and P8 = 6D, respectively, on the basis of illustration at (a) in Figure 4.

Next, zone vectors ZA and ZB are produced, as illustrated in Figure 4 at (b). With the term "zone vector", it is intended to mean, so to say, a bar-like table which is expansible and contractible in dependence on the position and the traveling direction of the associated car and which is constituted by the binary digits "1" corresponding to the hatched area of the floor service table of two bytes in the up- and down-directions UP and DN, respectively. However, the zone vector does not encompass the current position of the elevator car.

A service zone representative of the floors to be serviced by the elevator car is prepared by the associated microprocessor, as illustrated in Figure 4 at (c). The service zone is logically determined in the manner described below. For determination of the service zone SZA of the car No. A, following logical expressions apply valid.

SZA=ZA O Ze,whenPA < PB,anol SZA = ZA O ZB, when PA 3 PB where the logic symbol 0 represents exclusive-OR function. In the case of the example illustrated in Figure 4 at (c), the service zone SZA of the car No. A covers currently the fourth to eighth floors in the up-direction and the seventh floor in the down-direction, while the service zone SZB of the elevator car No. B extends from the sixth to the first floor in the down-direction and hence to the third floor in the up-direction.

Consequently, the hall calls issued in the service zones SZA and SZB may be selected as the hall calls to be processed. When expressed logically, AHA = HA'SZA AH8 = HB.SZb where AH represents the service to the hall call which in turn is denoted by H, and a dot "-" symbol represents a logical product.

An algorithm for processing the hall calls to be serviced has been briefed. Next, an example of the program executed on the basis of the above algorithm will be described in concrete.

Figure 5 illustrates a structure of a table made use of in executing a program for processing arithmetically the hall calls to be serviced by the control apparatus L1 of the elevator car No. A. It should be noted that the control apparatus L2 for the elevator car No. B makes use of a same table. The following description also makes reference to a flow chart shown in Figure 6 which illustrates a processing flow of the program executed for arithmetically processing the hall call to be serviced. This program is imparted with a lower priority than the car control program described hereinafter. Accordingly, unless interrupt for the program of higher priority occurs, this hall call processing program is repeatedly executed as a background processing.

The hall call processing program is activated instantly upon power-on of a power supply source. In the first place, interrupt is masked for initialization at a step 10. When the initializatin has been completed, the interrupt mask is removed at a step 30. The initialization effected at the step 20 includes the clearing of the random access memory or RAM, setting of register incorporated in the parallel interface adaptor PIA and the asynchronous interface adaptor ACIA, setting of the stack pointer and the like.

Next, at a step 40, supervisory control or management data is received from the car control apparatus of the other car and/or the data for supervisory control is transmitted to the control unit of the other elevator car. Such supervision or management data includes informations concerning the car position, the traveling direction (UP or DN) ofthe car, operation mode and the like. The data for the operation made includes informations or instructions concerning the exclusive or independent operation which is carried out independently from the other car, data of failure which has disenabled the supervisory control and the stoppage of operation in the stalled state. The mutual exchange of the supervisory control data mentioned just above is performed through the asynchronous interface adaptors ACIA shown in Figure 2 in a serial manner.An example of the program for processing the reception and transmission (i.e. exchange or transfer) of data for supervisory control is illustrated in Figure 7 in a flow chart.

Referring to Figure 7, this processing may be typically classified into the processing for data transmission and the processing for data reception, wherein the former is first executed.

Since the transmission processing of the supervisory control data is executed periodically at a predetermined interval, it is verified at a step 40-1 whether now is the time for data transmission. If the result is affirmative "YES", then subsequent processing steps for the data transmission are executed. In more particular, at a step 40-2, preparatory processing such as setting of the leading address and the number of data to be transmitted is performed, which is followed by a decision step 40-3 at which it is checked whether a transmission buffer register T of the asynchronous interface adaptor ACIA is emptied, i.e. whether or not the data transmission is allowed. When affirmative (YES), then the data transmission takes place at a step 40-4.On the other hand, when the result of the decision step 40-3 is negative, i.e. "NO", the processing preceding to the step 40-3 is repeated in a looped manner while checking the time-out for the transmission processing at a step 40-8. When the time-out occurs at the step 40-8, i.e. when the result of the decision step 40-8 is negative "NO", it is determined that failure has occured in the asynchronous interface adaptor ACIA.

It that case, a communication anomaly flag shown in Figure 5 is set to "1" at a step 40-9, with the result that the transmission processing is terminated.

In succession to the data transmission at the step 40-4, execution of the data transmission is repeated with some delay time to the preceding data transmission (step 40-4) until decision is made at a step 40-6 to the effect that all data has been completely transmitted. After the completed transmission of all data, posterior processing is executed at a step 40-7, whereupon all the data transmission processing comes to an end.

Next, the data reception processing is performed in a substantially same flow as the data transmission processing described above.

The data reception processing differs from the data transmission processing merely in that the former involves no delay time (the aforementioned step 40-5) and that a communication error check at a step 40-13 is added to the reception processing. Except for these differences, the reception processing is carried out in a manner similar to the processing for the data transmission described above.

It should be noted that the delay time involved at the step 40-5 of the data transmission processing is to assure the reception of data without fail regardless of delay possibly involved in the processing be software between the transmission and the reception of data. Accordingly, such delay time need not be provided in the data reception processing. The step 40-13 is added for checking whether data error ascribable to noises possibly admixed during the data reception or the like events is present or not. This error check may be realized in the asynchronous interface adaptor circuit ACIA by resorting to a parity check or the like. The result of the error check is stored at a communication anomaly flag shown in Figure 5.

After completion of the transmission/reception processing of the supervisory control or management data at the step 40 shown in Figure 6, decision is made at a step 50 as to the possible presence of transmission anomalies as well as the operation modes such as the exclusive or independent operation and the stoppage of operation on the basis of the contents of the communication anomaly flag and the associated car operation mode table. When the result of the decision step 50 is affirmative or "YES", all the contents of the associated car service zone table shown in Figure 5 are all set to logic "1" so that all the floors included in the whole service zone of the associated car can be serviced.This processing is executed for controlling the operation of the associated elevator car independently from the other car in the case where the latter is in a failure or stalled state, whereby the supervisory control is rendered invalid or impossible.

When the result of decision made at the step 50 in negative or "NO", the car operation is performed under the supervisory control. A routine for setting a dummy direction at a step 60 is executed in a manner illustrated in a flow chart of Figure 8. In the first place, it is decided whether both the cars No. A and No. B are in the direction-free state or not on the basis of the content concerning the car direction of the table shown in Figure 5. The direction-free state is represented by the table contents of "00". By the way, with the terms "direction-free state", it is intended to means that neither hall call nor car or cage call is issued. In this state, the elevator car may be allotted with an appropriate service zone.

When it is decided at the step 60-1 that both the cars No. A and No. B are in the direction-free state, then contents concerning the positions P1 and P2 of the cars No. A and No. B are read out from the table shown in Figure 5 and compared with each other. When the comparison results in the P1 3 P2, the up-direction UP is written in the table shown in Figure 5 at a section labelled with "DUMMY DIRECTION OF CAR NO. A", while the down-direction DN is set at a section labelled "DUMMY DIRECTION OF CAR NO. B". To the centrary, when P1 < P2, the setting of the above contents is reversed. If the result of decision at the step 60-1 is "NO", then it is decided at a step 60-2 whether either of the cars No. A or No. B is in the direction-free state on the basis of the relevant contents of the table shown in Figure 5.When the result of decision at the step 60-2 is "YES", then the table contents concerning the travel direction of the direction-bound car (i.e. the elevator car which is not in the direction-free state) is entered into the associated table section label led "DUMMY DIRECTION", while the contents representative of the direction opposite to the direction-bound car is placed in the associated table section "DUMMY DIRECTION" assigned for the direction-free car (step 60-4). When the result of decision at the step 60-2 is "NO", the contents set at the table sections "CAR DIRECTION" and representing the actuai directions of the cars No. A and No. Bare placed, as they are, in the table sections "DUMMY DIRECTION" for these cars at a step 60-2.

Referring again to Figure 6, after the dummy direction has been set at the step 60, setting of the dummy positions of the elevator cars are effected at a step 70 and at the same time comparison of these position data is performed. The dummy position data is represented by the vector value having a direction corresponding to the car travel direction and a magnitude corresponding to the car position as illustrated in Figure 4 at (a).

An exemplary processing program PGM2 for setting the dummy position and the comparison of positional magnitude is illustrated in Figure 9.

At first, the dummy position table section for the car No. A is located or determined. At a step 70-1, the table section "DUMMY POSITION OF CAR No. A" (Figure 5) is cleared. At a step 70-2, the contents of the table section "DUMMY DIRECTION OF CAR No. A" is checked. When the dummy direction is the up-direction UP, the contents of one byte of the table section "POSITION OF CAR NO. A" is set at the first byte of the table section "DUMMY POSITION OF CAR No. A" at a step 70-3. As described hereinbefore, each of the table sections "DUMMY POSITION" is constituted by two bytes with first byte being allotted to the up-direction UP, while the second byte is allotted to the down-direction DN (refer to Figure 3(b).When the dummy direction is decided as the down-direction DN at the step 70-2, then the contents of the table section labelled "CAR POSITION" is reversed in respect of the bit position (i.e. the more significant bits are relocated to the less significant bit positions and vice versa) and set at the second byte of the table labelled "DUMMY POSITION" at a step 70-4 in consideration of the fact that the up-direction UP and the down-direction DN follow contiguously each other in a closed loop, as illustrated in Figure 3 at (a). For example, assuming that the contents of the table section "CAR POSITION" is "00100000" and that the travel direction is down DN, the contents of the table "DUMMY POSITION" is "00000100" which corresponds to the ordinal reversion of "001 00000".

The processing described above is executed for the car No. B in a similar manner through the steps 70-5 to 70-8.

When the dummy position table sections have been set, magnitudes of the contents set in the position table section are compared with each other at a step 70-9. To this end, when the contents P8 (two bytes) of the table section "DUMMY POSITION OF CAR No. B" is subtracted from the contents PA (two bytes) of the table section "DUMMY POSITION OF CAR No. A", the resultant is reflected to a carry flag in dependence on the signs (positive or negative) of the difference.

The carry flag is set at the table section labelled "MAGNITUDE FLAG OF DUMMY POSITION" shown in Figure 5. Thus, the contents of the table "MAGNITUDE FLAG OF DUMMY POSITION" is "1" only when the dummy position of the car No. A is smaller than the dummy position of the elevator car No. B.

Referring agent to Figure 6, a program routine PGM3 for preparing the zone vectors is executed at a step 80 for determining the zone vectors ZA and ZB described hereinbefore in conjunction with Figure 4. This subprogram PGM3 is illustrated in a flow chart in Figure 10. The zone vectors ZA and ZB can be easily determined simply by subtracting "1" from the contents (two bytes) of the tables "DUMMY POSITION" at a step 80-1. For example, for the elevator car No. A, "0001000000000000" (table contents of dummy position of car No. A) - "0000000000000001" "0000111111111111" The resultant difference represents the contents of the zone vector table section for the car No. A, i.e. the table section labelled "ZONE VECTOR FOR CAR No. A" and thus set at this table. Similar processing is effected for the car No. Bat a step 80-2.

Next, at a step 90 shown in Figure 8, a program routine PGM4 for preparing the service zones is executed.

The development of this sub-program PGM4 is illustrated in a flow chart of Figure 11.

Referring to Figure 11, preparation of the service zones SZA and SZB can be accomplished through the exclusive OR function of the zone vectors ZA and ZB at a step 90-1, as described hereinbefore in conjunction with Figure 4(c). In this connection, it should however be mentioned that there may arise a case where the complement of the result of the above logical operation has to be determined in dependence of the magnitude flags of the dummy positions. For example, for determining the service zone SZA of the elevator car No. A, it is assumed that the car No. A is positioned at the fourth floor in the up-direction UP, while the elevator car No. B is positioned at the sixth floor in the down-direction DN (refer to Figure 4(a).Then, the service zone SZA is determined in the manner as follows: ZA = "0000000000001111" ZB= 0000001111111111" Thus, (3 Z8= "0000001111110000" In this case, since PA < Pe, the contents of the magnitude flag of the dummy position of the car No. A is "1 ".

Accordingly, the contents which is set at a table labelled "ASSOCIATED CAR'S SERVICE ZONE" is: SZA=ZA (3 ZB On the other hand, when the positional magnitude of the car No. A is greater than that of the car No. B, the corresponding magnitude flag of the dummy position is "0", with the result that the decision at a step 90-2 involves "NO". In this case, the complement of the contents set at the table section "ASSOCIATED CAR'S SERVICE ZONE" is determined and placed in the same table section in this case, the following logical expression applies: SZA=ZA e ZB="1111110000001111" When the associated car's service zone (that is, the service zone for the elevator car No. A in this exemplary case) is determined, then the associated car's hall calls are processed.A procedure to this end is illustrated in a flow chart in Figure 12. More particularly, assuming that the car in concern is the elevator car No. A and that a hall call of up-direction UP is issued at the sixth floor, while a hall call of down-direction DN is issued at the fourth floor, as illustrated in Figure 4, then a logical product of the contents set, respectively, at the table section "ASSOCIATED CAR'S SERVICE ZONE" and "HALL CALL" shown in Figure 5 is determined, whereby the hall call AHA to be serviced by the car No. A is determined as follows: SZA = "0000001111110000" HA = "0001000000100000" AHA = SZA.HA = "0000000000100000" The resultant AHA is then set at a table labelled "HALL CALL FOR ASSOCIATED CAR" shown in Figure 5. On the other hand, the hall call UP at the sixth floor is serviced by the car No. B.

In addition to the procedures and the arithmetic operations for processing the hall calls to be serviced, the supervisory control includes a dispersed stand-by control procedure (step 120 of Figure 6), according to which the elevator cars are located at various floor in a stand-by state in a predetermined dispersion or distribution pattern. This distributed stand-by control can be accomplished in a facilitated manner by issuing the dummy calls. A procedure to this end is illustrated in Figure 13. In the first place, it is checked at a step 120-1 whether or not the service call or calls are present. If the result of the check is "YES", the distributed or dispersed stand-by control is unnecessary. Accordingly, this subprogram PGM6 comes to an end. When there is issued no call, it is decided whether the associated elevator car is positioned at an allocated stand-by floor at a step 120-2.This check is acccomplished through comparison of the contents set, respectively, at the tables "HALL CALL" and "POSITION OF CAR No. A" shown in Figure 5. If the result of the check is affirmative or "YES", the execution of this program PGM6 comes to an end. When the check results in "NO", a dummy call signal for commanding the dispersed stand-by is read out from the read-only memory ROM and set at the table section "HALL CALL" at a step 120-3. Consequently, the decision at the step 120-2 is made on the basis of the dummy call set at the step 120-3.

Referring once again to Figure 6, a regulated operation processing step 130 and a patterned operation processing step 140 are additionally executed. With the terms "regulated operation", it is intended to mean that operations of the individual elevator cars are restrictively regulated upon occurrence of fire, earthquake, power service interruption and so forth for the purpose of assuring security of the passengers, as is well known in the art. For example, it is known that upon occurrence of power service interruption, a number of cars which is determined in dependence on capacity of the associated non-utility generation system are driven to the respective nearestfloors. In more particular, operation of an elevator system demands usually a large electric power. Accordingly, if the elevator cars, say, the cars No. A and No.B are to be driven by resorting to the non-utility generation, there may arise such a case that the power supply becomes inadequate before both cars has has reached the respective nearest floors. To evade such deficiency, the regulation control is made in such a manner that the associated car is driven to its nearest floor only after the arrival of the other car at the nearest floor has been confirmed.

With the terms "patterned operation", it is intended to mean that the operation of the elevator system is carried out in accordance with specific operation patterns at the office opening time, the closing time and the lunch time. For example, at the office opening time, preference is put on the car operation in the up-direction from a lobby floor (usually the first floor), while at the closing time preference is usually put on the down-operation toward the lobby floor. Further, at the lunch time, a concentrated operation to a dining hall or floor is conducted. Thus, at the patterned operation processing step 140, the car No. A will be dispatched to the lobby floor at express speed at the office opening time, when the other car, say, the car No. B is not present or dispatched to that floor, by way of example.These pattern operations are carried out during preselected periods determined by a time piece. Further, the pattern operations are made possible by storing contents of a pattern operation read out from the read-only memory in the table "ASSOCIATED CAR'S SERVICE ZONE" or alternatively by setting appropriate contents in the table section "HALL CALL FOR ASSOCIATED CAR", as the case may be.

Next, description will be made on a program for controlling the individual car operations. Figure 14 illustrates in a flow chart a subprogram for processing speed command for the elevator car No. A. Every time the car has reached a predetermined acceleration or deceleration time point or position, an interrupt request IRQ1 is issued to the main processing unit of the car operation control system, resulting in that the program shown in Figure 6 and being executed at that time is temporarily interrupted and the logical processing of the acceleration or deceleration command is performed in a hitherto known manner. For acceleration of the car, a speed command voltage which varies in a step-like manner at predetermined time interval is utilized.

When the car is driven at a constant speed, the speed command voltage is fixed. Finally, for the deceleration of the car, a speed command varying at a predetermined distance interval is made use of to park the car at a predetermined landing floor. When the processings mentioned above have been completed, the program being interrupted until then is restored.

Figure 15 shows a flow chart to illustrate a car signal control processing for the elevator car No. A. The car signal control processing program is activated periodically by a clock signal of a predetermined frequency, whereupon the supervisory control processing illustrated in Figure 6 and being executed by the main processing unit MPU is temporarily interrupted for executing the car signal control processing program. It goes without saying that the supervisory control processing (Figure 6) is restored upon completed execution of the car signal control processing (Figure 15).

Now, referring to Figure 15, a watch dog timer is first set at a step 3001 for supervising if a sequence processing has been completed within a predetermined time duration. Further, timer values are utilized in the logical processing of door control and the like which are carried out under control of the timer. At a second step 3002, car control signals such as the car position signal, the car call signal and other signals indicative of operating conditions of various safety means or the like are fetched as the input signals. The position of the elevator car is determined on the basis of the contents of an up-down counter which is destined for incrementing the count contents in response to pulses generated from a pulse generator when the car runs in the up-direction and count down the contents correspondingly when the car is traveling in the down-direction.The pulse generator produces these pulses in proportion to a driving quantity of the elevator driving system. The car or cage call is activated by pushing a cage call is activated by pushing a cage call button CA provided within the car (Figure 1) and registrated in the random access memory RAM. The safety means include limit switches for detecting the upper and the lower limits of a car maneuver range, detector switches for detecting opened or closed state of the car door, and the like detecting or sensor means. The car control inputs include a signal indicative of the manually set independent operation mode, a signal indicative of operation stoppage mode, a signal representative of the set pattern operation and so forth.

At a step 3003, the operation mode as well as other required operating conditions are selected on the basis of the input signals fetched at the step 3002 to thereby effect required settings. The operation mode selected at this step is stored in the associated table labelled "OPERATION MODE" shown in Figure 5.

At a step 3004, control is so made that the door is opened and closed smoothly without giving rise to any danger to the passengers. This control may be carried out in a manner known in the art. At a step 3005, the car position is determined on the gasis of the contents in the up-down counter described above in conjunction with the step 3002 and set in the associated table section labelled "CAR POSITION" shown in Figure 5. At a step 3006, the car or cage call fetched at the step 3002 is registrated in a car call table prepared in the random access memory RAM. At a step 3007, the hall call fetched at the step 3002 is entered in the hall call table section "HALL CALL" shown in Figure 5. At a step 3009, selective determination is made as to the operating direction (i.e. UP, DN or direction-free) of the associated car on the basis of the car call, hall call and car position signals fetched at the step 3002 and entered in the allocated table section "TRAVEL DIRECTION".

At a step 3010, running controls such as start, stop, acceleration and slow-down controls are performed on the basis of the data obtained through logical processing of the program illustrated in Figure 14 by supplying appropriate commands to relevant relays, contactor or a motor. At a step 3011, a floor next to be serviced is seleted on the basis of the contents stored in the tables "HALL CALL FOR ASSOCIATED CAR" and "CAR CALL" shown in Figure 5, whereby a command to stop or park the car at the selected floor is set.

As a step 3012, the reasonability of the program sequence is checked in a known manner. In case there arises a trouble which disenables the safety operation under the supervisory control, for example, in case the elevator is instructed to move when the door is opened, a binary bit "1" is set at an operation failure flag of the allotted table section "OPERATION MODE" shown in Figure 5. At a step 3014, the current position or location of the car (a position ahead of the car when it is running) is displayed in a car position indicator provided in the car and the halls. This step is executed on the basis of the contents stored in the allotted car position table section "CAR POSITION". Further, a flicker display may be made in the vicinity of parking floor hall, as the case may be.

Although description has been made as to the destinations to which the control commands of the elevator care are directed upon execution of every step, it should be understood that the results of the processings performed at the various steps are supplied to the relevant parts through associated interface circuits at the step 3015. At a step 3016, the reset signal is applied to the watch dog timer which is constructed of a hardware structure so as to monitor a runaway of the computer program, that is a failure of the microcomputer. If the watch dog timer is not triggered by the reset signal from the software within a predetermined time set to the watch dog timer, the decision is made as the microcomputer is in failure.In this case, since the car control apparatus cannot keep in communication with the another car control apparatus, at step 3003, a binary bit "1" is set at the failure flag of the table section "OPERATION MODE" shown in Figure 5.

In the foregoing, an example of the operation control program for the elevator car No. A has been described by referring to Figure 15. It will, however, be appreciated that the operation control program for the car No. B is executed in a similar manner.

The exemplary embodiment of the present invention described above involves following advantages effects.

First, by virtue of such system feature that the control program for supervising a group of elevator cars is provided in each of the computers provided in the control apparatus of the individual elevator cars, respectively, it is unnecessary to provide additionally a central supervisory control apparatus, whereby not only the expenditure for the hardware but also the maintenance cost can significantly be reduced, to an advantage.

Second, since the system for supervising a group of elevator cars according to the invention is implemented in such manner that each control apparatus performs the operation control of its own car on the basis of data or informations about its own car as well as the data received from the other cars (i.e. the control apparatus determines arithmetically or logically the hall calls to be serviced by the associated car in consideration of the operating conditions of the other cars), a same processing program can be employed for all the car control apparatus, which in turn means that the corresponding hardwares can be implemented in the same configuration, to a great advantage in respect to the standardization, production control, exchangeability and the maintenance of the car control apparatus.

Third, even when another car is brought to shutdown for some reasons, the remaining cars can continue to perform the services under the control of their own control apparatus, respectively, whereby an improved reliability can be assured.

Fourth, since the supervisory control processing program is imparted with a lower preference or priority than-the car operation control program which has to be executed with quick response, any adverse influence to the latter can be positively suppressed.

Fifth, since the communications between or among the individual cars can be effected serially in a facilitated manner, the supervisory control can be realized in a simplified arrangement without involving any substantial increase in the number of conductors or wires for the mutual communication.

Next, another exemplary embodiment of the invention will be described by referring to Figure 16. In the case of the example described above, it has been assumed that the number of the cars to be supervised is two. It goes, however, without saying that the invention can be applied to the supervisory control for the elevator system including more than two elevator cars. Figure 16 illustrates algorithm for arithmetically processing the hall calls to be serviced by three cars. The dummy direction is determined in the same manner as described hereinbefore. Preparations of the dummy position tables as well as the zone vectors can be made in the similar manner. However, for the elevator system which includes three or more cars, the magnitude flags of the dummy positions can be no more used.Instead, the dummy positions of the individual cars can be discriminated by identifying them by the lower position PL, a middle position PM and the highest position PH. In the case where two or three cars are located at a same floor, the car labelled with a smaller ordinal car number may be considered as the car located at a lower position. In this way, the zone vectors ZL, ZM and ZH as well as the service zones SZL, SZM and SZH can be determined as illustrated in Figure 16. As can be seen from this figure, it is sufficient to previously prepare a table of correspondences between the elevator car numbers A, B and C and the flower ievels L, M and H.

The service zones SZL, SZM and SZH are given by the following logical expressions: SZL=ZL Q3 ZM SZM=ZM 3 ZH SZH = ZH Q3 ZL For example, for the dummy positions illustrated at (a) in Figure 16, following relations apply valid: PL=Ps PM = PA PH = Pe Therefore, the service zones of the individual elevator cars are as follows: SZA = SZM SZB = SZL SZe = SZH The service zones for more than three cars can be determined in a similar manner.

The relevant processing program will readily occur to those skilled in the art from the beforementioned processing programs for the elevator system including two cars and thus description will be omitted. It will be appreciated that even when one of three or more cars is brought to shutdown or set to the independent operation mode for failure or the like reason, other elevator cars can be operated under the supervisory group control on the basis of the contents in the operation mode tables, whereby the supervisory operating performance and reliability can be significantly improved.

It will now be understood that the invention has provided an improved elevator car operation control apparatus which is capable of performing with a high reliability a supervisory control for a number of elevator cars adapted for parallel operation in a simplified arrangement in which the functions for the supervisory control are distributed among the digital control apparatus each provided for the individual cars so that the digital control apparatus for one car is able to control the call servicing operation of the associated (i.e. its own) car on the basis of data input from the other car.

Claims (13)

1. An elevator operation control system, comprising a plurality of elevator cars adapted to be operated in parallel for serving a plurality of floors of a building and a plurality of car control apparatus each provided in association with a corresponding one of said elevator cars, respectively, for controlling individually operation of the associated elevator car, wherein each of said car control apparatus includes input/output means for transmitting informations concerning at least position and travel direction of said associated car to the other car control apparatus associated with the other elevator cars and receiving informations concerning at least positions and travel directions of the other elevator cars from the other car control apparatus, and a supervisory control unit for controlling operation of said associated elevator car in consideration of the informations concerning the positions and the travel directions of said other elevator cars.

2. An elevator operation control system according to claim 1,wherein said supervisory control unit includes a memory means for storing a supervisory control program for managing and controlling services to be carried out by said associated elevator car on the basis of the informations received from the other car control apparatus and an associated car control program for controlling operation of said associated elevator car, and a processing unit for executing program controls in accordance with said two types of programs.

3. An elevator operation control system according to claim 2, wherein said associated car control program is imparted with a higher processing priority than said supervisory control program.

4. An elevator operation control system according to claim 3, wherein said supervisory control program is adapted to be processed in a closed loop.

5. An elevator operation control system according to claim 3 or 4, wherein said associated car control program is adapted to be periodically activated at a predetermined time interval.

6. An elevator operation control system according to claim 1, wherein said supervisory control unit includes means for determining hall calls to be serviced by the associated elevator car on the basis of the informations concerning the positions and the travel directions of said other cars and said associated car.

7. An elevator operation control system according to claim 6, wherein said hall call determining means includes means for determining a service zone of said associated elevator car on the basis of the informations concerning the positions and the travel directions of said other elevator cars and said associated cars, and means for commanding said associated elevator car to make services in response to the only hall calls that are issued within said service zone.

8. An elevator operation control system according to claim 1, wherein provided that a direction-free elevator car whose travel direction is not determined is present among said plurality of elevator cars, said supervisory control unit includes means for setting the travel direction of said direction-free elevator car in conjunction with the position of said direction-free elevator car as well as the positions and the travel directions of the other elevator cars.

9. An elevator operation control system according to claim 1,wherein when at least given one of said plural elevator cars becomes insusceptible to the supervisory control, said supervisory control unit is adapted to perform the supervisory control on the basis of the informations concerning the positions and the travel directions of the other elevator cars.

10. An elevator operation control system according to claim 1, wherein said input/output means is further adapted to transmit informations about operation modes of the associated elevator car to the car control apparatus of the other elevator cars and receive informations about operation modes of said other elevator cars, said car control apparatus being adapted to manage and control the associated elevator car in accordance with the received informations about the operation modes.

11. An elevator operation control system according to claim 10, wherein said operation modes include at least one of an independent car operation mode, an operation failure mode and a shutdown mode.

12. An elevator operation control system according to claim 1, wherein said supervisory control unit includes means for determining a floor at which the associated car is to be parked in a predetermined stand-by car distribution pattern when no service calls are present.

13. An elevator operation control system substantially as hereinbefore described with reference to, and as illustrated in, Figure 1; or Figure 2; or Figures 3 and 4; or Figure 5; or Figures 6 to 13; or Figure 14; or Figure 15; or Figure 16 of the accompanying drawings.