Abstract:
A system and method for controlling multiple elevator cabs in an elevator shaft of a structure, where at least one elevator shaft having a plurality of zones, each zone representing at least one floor of the structure; at least one zone having at least one sensor; at least two elevator cabs moveable within the shaft, each cab moveable independently of other cabs; and a controller that determines movement of each cab into a zone. A first cab preceding any other cab, designated a leading cab; each cab following the leading cab, designated as a trailing cab; each cab moveable in the same direction of travel to service zones until each cab reaches its designated end zone; wherein the controller only instructs a trailing cab to move into a zone with a sensor, after the sensor in the zone detects a cab that was located in such zone has exited that zone thereby preventing collisions.

Description:
FIELD OF INVENTION 
       [0001]    The invention generally relates to a system and method for controlling the motions and positions of multiple elevator cabs which move independently of each other in an elevator shaft. 
       BACKGROUND 
       [0002]    At the present time there is no safe, simple, efficient and low cost method for controlling the motions and positions of multiple elevator cabs that move independently of each other in the same elevator shaft. 
         [0003]    Most current elevator control systems which control multiple cabs in the same shaft, only operate with one elevator cab in each separate region of each elevator shaft, so it is physically impossible for two cabs to collide. Some of these systems express cabs from the ground floor to groups of upper floors and then operate just one cab in each group of floors. All of these systems are very inefficient because each region of each elevator shaft is only being used by one elevator cab. Other high tech control systems propose that multiple cabs can be operated independently of each other in each elevator shaft where sensors attempt to prevent collisions by sensing the speed of each cab and their distances apart, so that a computer can attempt to adjust the speed and distance of each moving cab in the same elevator shaft. However, most of these systems are very complicated, unreliable, expensive and unsafe, because many unexpected things can happen to cause collisions, such as power losses, power fluctuations, data cross feeds, a sensor can fail, there can be an electrical cross circuit, computers can crash, and so forth. A few systems have mechanical collision prevention methods, but they too can fail, and they are clumsy, require slow elevator speeds, and are limited to two elevator cabs. 
         [0004]    While it is true that all elevator systems can be exposed to earthquakes, hurricanes, tornadoes, lightning, floods, fires, sabotage, terrorism, low flying airplanes or the like, these possible extraordinary occurrences should not be attributed to an otherwise fail safe computer control system or its method of operation. Accordingly, there is a need for a simple, efficient, low cost and a failsafe computer control system and method thereof which solves all the problems as discussed above. 
       SUMMARY 
       [0005]    Embodiments of the present invention describe a method and system for elevator cabs moving independently of each other in the same elevator shaft to move and operate safely, efficiently, and to keep them from colliding with each other. In an embodiment, the invention employs elevator shaft zones and shaft sections, sensors, video cameras, computers and computer programs to achieve this result. The first moving cab in a group of moving elevator cabs can move in any direction (either up or down) without restriction throughout an elevator shaft, because there is no other elevator cab in front of it that it could collide with. However, a programmed computer must restrict the areas of a shaft that other following cabs can enter, to shaft zones and sections which sensors and cameras indicate are devoid of other cabs. In this manner multiple elevator cabs can move independently of each other through an elevator shaft safely, rapidly and efficiently to service passengers that desire to travel to any destination floor in a structure. 
         [0006]    A major purpose of this invention is to describe, explain and demonstrate such a control system using shaft zones and sections, sensors, video cameras, computer programs, and computers to control the motions and positions of multiple elevator cabs moving up or down an elevator shaft in a low-rise, a mid-rise and a high-rise building or structure, in order to prevent such cabs from colliding with each other. 
         [0007]    Embodiments of the present invention are as failsafe as any current elevator systems where only one elevator cab can operate in each elevator shaft, because the present inventive method and system prevents an elevator cab from moving to the next possible zone or section of an elevator shaft until after multiple redundant sensors all indicate to an operating computer that such zone or section is completely empty, and devoid of other elevator cabs or any other possible obstructions. At the same time, a benefit of the present invention allows for more than one cab to service a region of an elevator shaft, resulting in better efficiency for passengers and building owners. 
         [0008]    According to an embodiment of the present invention, there is an elevator system for controlling two or more elevator cabs in an elevator shaft of a structure, the elevator system comprising: at least one elevator shaft having a plurality of zones, each zone representing at least one floor of a structure; one or more zones of the plurality of zones having at least one sensor; at least two elevator cabs moveable within said at least one elevator shaft and each cab moveable independently of other cabs, wherein a first cab preceding any other cab is designated a leading cab, and each cab following the leading cab is designated a trailing cab; wherein each of the cabs is moveable in a same direction of travel to service zones until each cab has reached its designated end zone. The system further comprising a controller that determines movement of each elevator cab into a zone wherein the controller only instructs a trailing cab to move into a zone with a sensor, hereinafter referred to as the subject zone, after the sensor in said subject zone detects that a cab that was located in such subject zone has exited that subject zone. 
         [0009]    According to other embodiments of the present invention, there is a computer-implemented method for controlling multiple elevator cabs in at least one elevator shaft of a structure wherein each cab is moveable independently of the other cabs, the computer comprising a processor, a memory operatively coupled to the processor, the memory storing code executed by the processor for implementing the method; and in another embodiment there is also a computer program product stored on a non-transitory computer readable medium having instructions recorded thereon, that when executed by one or more processors cause the one or more processors to implement a method; wherein the method comprising: detecting a passenger request from a desired zone and in a desired first direction of movement, where a zone represents at least one floor of the structure; directing at least one cab of a set of multiple elevator cabs to begin moving toward the desired zone, all other cabs of the set of multiple elevator cabs are programmed to remain stationary or move in the same first direction of movement as the at least one cab; directing the at least one cab to service passengers to or from the desired zone along the first direction of movement until reaching an end zone; directing at least a second cab of the set of multiple elevator cabs to service passengers to or from a desired zone along the same first direction of movement of the at least one cab until reaching at least a second end zone; and directing at least one cab of the set of multiple cabs to initiate travel in an opposite direction of movement to the first direction, only after each of all of the multiple cabs have reached its designated end zone. 
         [0010]    These and other aspects of the present invention are further made apparent, in the remainder of the present document, to those of ordinary skill in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings where: 
           [0012]      FIG. 1  illustrates an elevator shaft in a 12-floor structure with two elevator cabs (Y and Z) positioned on the bottom two floors of the shaft, according to one embodiment of the present invention. 
           [0013]      FIG. 2  illustrates two elevator shafts (I and II) in a 12-floor low-rise structure with two elevator cabs (Y and Z) positioned on the bottom two floors of Shaft I and with two other elevator cabs (W and X) positioned on the bottom two floors of Shaft II, according to an embodiment of the present invention. 
           [0014]      FIG. 3  illustrates three elevator shafts (I, II and III) in a 34-floor mid-rise structure with three elevator cabs (T, U and V) positioned on the bottom three floors of Shaft I, with three other elevator cabs (Q, R and S) positioned on the bottom three floors of Shaft II, and with three other elevator cabs (N, O and P) positioned on the bottom three floors of Shaft III, according to an embodiment of the present invention. 
           [0015]      FIG. 4  illustrates four elevator shafts (I, II, III, and IV) in a 90-floor high-rise structure with four elevator cabs (J, K, L and M) positioned on the bottom four floors of Shaft I, with four other elevator cabs (F, G, H and I) positioned on the bottom four floors of Shaft II, with four other elevator cabs (B, C, D and E) positioned on the bottom four floors of Shaft III, and with four other elevator cabs (A, Λ, II, and Ω) positioned on the bottom four floors of Shaft IV, according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    This invention and elevator computer control system and method can operate in conjunction with any conventional control systems which employ two button lobby calls (up or down), and destination buttons located inside of each cab. It can also operate in conjunction with more sophisticated control systems, such as a destination computer control system where a passenger in a lobby indicates his/her desired destination floor on a ten key pad and a computer indicates which elevator cab in which elevator shaft the passenger should enter to travel to his/her desired destination in the shortest possible time. 
         [0017]    In this invention and elevator control system, all sensors and video cameras indicate to the central control system that which they detect. There can be two types of elevator cabs in a group of cabs moving independently up or down in an elevator shaft: leading cabs and trailing cabs. A leading cab is the first cab in a group of elevator cabs that moves and leads the other cabs in any direction, either up or down. All other cabs which follow the leading cab in any direction are designated as trailing cabs. The central computer must restrict the areas of each shaft that a trailing cab can enter, to shaft zones and sections which sensors indicate are devoid of other cabs. On the other hand, leading cabs are not restricted as to the zones or sections that they can enter, because there are no other cabs in front of leading cabs that they could collide with. However, each cab in a shaft can only move in one direction (up or down) from its beginning position to its ending position in that direction through an elevator shaft. 
         [0018]    References in the specification to “one embodiment” or to “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in a least one embodiment of the invention. The appearances of the phrase “an embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
         [0019]    In addition, the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the claims. 
         [0020]    Preferred embodiments of the present invention will now be described and explained with reference to the figures where like reference numbers and letters indicate identical or functionally similar elements. 
         [0021]    A view from the front of an embodiment of a multi-cab elevator shaft in a 12-floor structure is illustrated in  FIG. 1 . Each floor of the structure can represent a zone in which cabs in the shaft may be positioned. Each zone is designated by a number or a letter located next to each zone. The direction that each elevator cab can move can be indicated by the word ‘up’ above the shaft, and by the word ‘down’ below the shaft. At the bottom of the shaft there can be a carpark zone (B), and at the top of the shaft there can be an attic zone (A). 
         [0022]    In the bottom two zones of the shaft there can be two elevator cabs respectively designated by the letters Y and Z. Cab Y can be positioned in zone  1  and Cab Z can be positioned in zone B. 
         [0023]    There can be one or more electronic sensors located in each zone. Electronic sensors located on the top and bottom of each cab can detect the distance between cabs and the speed of closure or separation between cabs. If the distance between cabs becomes too close for the speed of closure, a computer and/or an elevator governor can apply brakes to slow a cab down to a safe speed or distance. Each sensor can be connected to a central computer which can be programmed to control all of the motions and functions of each elevator cab in a structure. Sensors can also be mechanical sensors or other types of sensors, such as laser sensors. 
         [0024]    Each cab can have one or more video cameras/devices or other visual indicators, located on the top and on the bottom of the cab, or elsewhere on the cab. Each video camera can be focused on the shaft in each direction of the cab&#39;s motion through the shaft. Each sensor can have a video camera focused on an illuminated zone of the shaft. All sensors and video cameras can be connected to computer screens in the central operations room of the elevator system. Each cab can also have a video camera mounted on the inside center of the cab&#39;s ceiling which can scan the inside of the cab. 
         [0025]    If there is a failure or other problem with any cab, with any sensor, with any camera, with any part of the shaft, with any other element of the system, or a conflict between any sensor or any camera, one or more alarms can be programmed to sound in the central operations room, and a human attendant can be instructed to immediately see what, if anything, is happening. The motions and functions of any cab can be manually controlled by a human attendant. 
         [0026]    The number, location and/or description of the shaft, floors, zones, sequential steps, elevator cabs, computers, computer programs, cameras and any other element of the invention can vary, as desired by the system operator. 
         [0027]    When a sensor is referred to in any zone, as described in the specification, this means and includes: 1) all sensors that are positioned in such zone; 2) that each sensor independently detects that such zone is empty; and 3) that each sensor is fully operational. 
         [0028]    Examples of the motions and changed positions of each cab in the elevator shaft of the structure will hereafter be described in sequential steps, in order to demonstrate and explain the control system and method, according to an embodiment of the present invention. 
         [0029]    Step 1. Trailing Cab Z can load carpark passengers in zone B of  FIG. 1 . Leading Cab Y can load passengers in zone  1  of the structure. Cab Y can then move up the shaft and service passengers in the shaft. 
         [0030]    Step 2. After a sensor in zone  1  indicates that leading Cab Y has exited zone  1 , trailing Cab Z can move up into zone  1  and load passengers. 
         [0031]    Step 3. Leading Cab Y can continue servicing passengers in the shaft. After a sensor in zone  5  indicates that leading Cab Y has exited zone  5 , trailing Cab Z can move up out of zone  1  and service other passengers in all zones below zone  6 . 
         [0032]    Step 4. When leading Cab Y moves into zone  10  all remaining passengers in Cab Y can be unloaded on Floor  10 . Leading Cab Y can then move up into the attic zone A and stop. 
         [0033]    Step 5. After a sensor in zone  10  indicates that leading Cab Y has exited zone  10 , trailing Cab Z can move up into zone  6  and service passengers in all zones below zone A. 
         [0034]    Step 6. When trailing Cab Z moves into zone  10 , Cab Z can unload all remaining up passengers, and then load down passengers. 
         [0035]    Step 7. Cab Z (the new leading cab) can then exit zone  10  and move down the shaft to service passengers in the shaft. 
         [0036]    Step 8. After a sensor in zone  10  indicates that leading Cab Z has exited zone  10 , new trailing Cab Y can move down out of zone A and into zone  10  and load down passengers. 
         [0037]    Step 9. Leading Cab Z can continue servicing passengers in the shaft. After a sensor in zone  6  indicates that Cab Z has exited zone  6 , trailing Cab Y can move out of zone  10  and service passengers above zone  5 . 
         [0038]    Step 10. After leading Cab Z enters zone  1 , Cab Z can unload passengers on zone  1 . Cab Z can then move down into carpark zone B, unload passengers and stop. 
         [0039]    Step 11. After sensors in zone  1  indicate that leading Cab Z had exited zone  1 , trailing Cab Y can move down into zone  5  and service passengers above zone B. 
         [0040]    Step 12. When trailing Cab Y enters zone  1 , Cab Y can stop. Then all remaining passengers in Cab Y can unload and exit the structure. 
         [0041]    Once a cycle of sequential steps is completed, this process can be continuously repeated all over again, until it is terminated by a computer or by a human attendant. As demonstrated by the above steps, each of the cabs in the shaft is moveable in the same direction of travel to service zones until each cab has reached its designated end zone. After all cabs in a shaft have completed reaching their designated end zones, travel can be initiated in an opposite direction of travel than the direction just completed. As illustrated by the sequence of steps of the above described embodiment, the controller of the system only instructs a trailing cab to move into a desired zone with a sensor, after the sensor detects and indicates to said computer that a cab that was located in such desired zone has exited that desired zone. A view from the front of an embodiment of two multi-cab elevator shafts (I and II) in a 12-floor low-rise structure is illustrated in  FIG. 2 . Each floor of each shaft can represent a zone in which cabs in that shaft may be positioned. Each zone in each shaft is designated by a number or a letter located next to each zone. Each shaft can be divided into two or more sections: a lower section and an upper section. Each section represents a plurality of zones. The direction that each elevator cab can move in each shaft can be indicated by the word ‘up’ above each shaft, and by the word ‘down’ below each shaft. At the bottom of each shaft there can be a carpark zone (B), and at the top of each shaft there can be an attic zone (A). 
         [0042]    In the bottom two zones of Shaft I there can be two elevator cabs respectively designated by the letters Y and Z. Cab Y can be positioned in zone  1  and Cab Z can be positioned in zone B. In the bottom two zones of Shaft II there can be two other elevator cabs respectively designated by the letters W and X. Cab W can be positioned in zone I and Cab X can be positioned in zone B. 
         [0043]    There can be one or more electronic sensors located in each zone of each shaft. Each sensor must indicate that no cab is in such zone before a trailing cab may enter and operate in such zone. Electronic sensors on the top and bottom of each cab can detect the distance between cabs and the speed of closure or separation between cabs. If the distance between cabs becomes too close for the speed of closure, a computer and/or an elevator governor can apply brakes to slow a cab down to a safe speed or distance. Each sensor can be connected to a central computer which can be programmed to control all of the motions and functions of each elevator cab in a low-rise structure. Sensors can also be mechanical sensors or other types of sensors, such as laser sensors. It is noted that the sensors on each end of each cab may serve as another layer of safety in case all zone and section sensors fail, making sure that no other obstruction (i.e. a man or an animal or object) is between the cab and the next zone, and to slow a cab down if necessary. 
         [0044]    Each cab can have one or more video cameras or other visual indicators, located on the top and on the bottom of the cab, or elsewhere on the cab. Each video camera can be focused on the shaft in each direction of the cab&#39;s motion through the shaft. Each sensor can have a video camera focused on an illuminated zone or section of a shaft. Each video camera may be equipped with a corresponding illuminator as well. All sensors and video cameras can be connected to computer screens in the central operations room of the elevator system. Each cab can also have a video camera mounted on the inside center of the cab&#39;s ceiling which can scan the inside of the cab. 
         [0045]    If there is a failure or other problem with any cab, with any sensor, with any camera, with any part of any shaft, with any other element of the system, or a conflict between any sensor or any camera, one or more alarms can be programmed to sound, in the central operations room, and a human attendant can be instructed to immediately see what, if anything, is happening. The motions and functions of any cab can be manually controlled by a human attendant. 
         [0046]    The number, location and/or description of shafts, floors, zones, sections, sequential steps, elevator cabs, computers, computer programs, cameras and any other element of the invention can vary, as desired by the system operator. 
         [0047]    When sensors are referred to in any zone of any shaft, as described in the specification, this means and includes: 1) that all sensors that are positioned in such zone; 2) that each sensor independently detects that such zone is empty; and 3) that each sensor is fully operational. 
         [0048]    Examples of the motions and changed positions of each cab in each elevator shaft of a low-rise structure will hereafter be described in sequential steps, in order to demonstrate and explain the control system and method, according to an embodiment of the present invention. 
         [0049]    Step 1. Trailing Cab Z can load carpark passengers in zone B of Shaft I. Leading Cab Y can load passengers in zone  1  on the ground floor of a low-rise structure. Cab Y can then move up Shaft I and service passengers in the lower section of Shaft I. 
         [0050]    Step 2. After sensors in zone  1  indicate that leading Cab Y has exited the ground floor zone  1 , trailing Cab Z can move up into zone  1  and load passengers. 
         [0051]    Step 3. Leading Cab Y can then move up into zone  6  and service passengers in the upper section of Shaft I. After sensors in zone  5  indicate that leading Cab Y has exited zone  5 , trailing Cab Z can move up out of zone  1  and service other passengers in the lower section of Shaft I. 
         [0052]    Step 4. When leading Cab Y moves into zone  10  all remaining passengers in Cab Y can be unloaded on Floor  10 . Leading Cab Y can then move up into the attic zone A and stop. 
         [0053]    Step 5. After sensors in zone  10  indicate that leading Cab Y has exited zone  10 , trailing Cab Z can move up into zone  6  and service passengers in the upper section of Shaft I. 
         [0054]    Step 6. When trailing Cab Z moves into zone  10 , Cab Z can unload all remaining up passengers, and then load down passengers. 
         [0055]    Step 7. At this approximate point in time, Cabs W and X in Shaft II of a low-rise structure can begin to execute the aforementioned steps 1 through 6 in Shaft II. 
         [0056]    Step 8. Cab Z (the new leading cab) can then exit zone  10  and move down Shaft I to service passengers in the upper section of Shaft  1 . 
         [0057]    Step 9. After sensors in zone  10  indicate that leading Cab Z has exited zone  10 , new trailing Cab Y can move down out of zone A and into zone  10  and load down passengers. 
         [0058]    Step 10. Leading Cab Z can then move down into zone  5  and service passengers in the lower section of Shaft  1 . After leading Cab Z enters zone  1 , Cab Z can unload passengers on the ground floor of a low-rise structure and then move down into carpark zone B and unload and load passengers. 
         [0059]    Step 11. After sensors in zone  6  indicate that leading Cab Z has exited zone  6 , trailing Cab Y can move down into zone  9  and service passengers in the upper section of Shaft I. 
         [0060]    Step 12. After sensors in zone  1  indicate that leading Cab Z has exited zone  1 , trailing Cab Y can move down into zone  5  and service passengers in the lower section of Shaft  1 . 
         [0061]    Step 13. After trailing Cab Y enters zone  1 , Cab Y can stop. Then all remaining passengers in Cab Y can unload and exit the low-rise structure. 
         [0062]    Step 14. At this approximate point in time, Cabs W and X in Shaft II of a low-rise structure can begin to execute the aforementioned sequential steps 8 through 13 in Shaft II, while Cab Y and Cab Z can begin to execute their previously mentioned sequential steps 1 through 6 again in Shaft I. 
         [0063]    Once a cycle of sequential steps is completed, this process can be continuously repeated all over again, until it is terminated by a computer or by a human attendant. 
         [0064]    Thus, when elevator cabs in Shaft I and Shaft II in a low-rise structure operate together in sequence, their traffic pattern can become circular. This means that there can always be elevator cabs moving up in a shaft in sequence in the low-rise structure while other elevator cabs in the other shaft are moving down in sequence. Therefore, no passenger in a low-rise structure must wait very long to be serviced by an elevator cab moving up or down. 
         [0065]    A view from the front of an embodiment of three multi-cab elevator shafts (I, II and III) in a 34-floor mid-rise structure is illustrated in  FIG. 3 . Each Shaft can be divided into three sections: a lower section, a middle section, and an upper section. Each floor of each shaft can represent a zone in which cabs in that shaft may be positioned. Each zone in each shaft can be designated by a number and/or a letter located next to each zone. The direction that each cab can move in each shaft can be indicated by the word ‘up’ above each shaft, and by the word ‘down’ below each shaft. At the bottom of each shaft there can be two carpark zones (B 1  and B 2 ), and at the top of each shaft there can be two attic zones (A 1  and A 2 ). 
         [0066]    In the bottom three zones of Shaft I there can be three elevator cabs respectively designated by the letters V, U and T. Cab V can be positioned in zone B 2 , Cab U can be positioned in zone B 1 , and Cab T can be positioned in zone  1 . In the bottom three zones of Shaft II there can be three other elevator cabs respectively designated by the letters S, R and Q. Cab S can be positioned in zone B 2 , Cab R can be positioned in zone B 1 , and Cab Q can be positioned in zone  1 . In the bottom three zones of Shaft III there can be three other elevator cabs respectively designated by the letters P, O and N. Cab P can be positioned in zone B 2 , Cab O can be positioned in zone B 1 , and Cab N can be positioned in zone  1 . 
         [0067]    There can be one or more electronic sensors located in each zone of each shaft. Electronic sensors on the top and bottom of each cab can detect the distance between cabs and the speed of closure or separation between cabs. If the distance between cabs becomes too close for the speed of closure, a computer and/or an elevator governor can apply breaks to slow a cab down to a safe speed or distance. Each sensor can be connected to a central computer which can be programmed to control all of the motions and functions of each elevator cab in a mid-rise structure. Sensors can also be mechanical sensors or other types of sensors, such as laser sensors. 
         [0068]    Each cab can have a video camera located on the top and on the bottom of the cab. Each video camera can be focused on the shaft in each direction of the cab&#39;s motion through the shaft. Each sensor can have a video camera focused on the zone of its responsibility. All sensors and video cameras can be connected to computer screens in the central operations room of the elevator system. Each cab can also have a video camera mounted on the inside center of the cab&#39;s ceiling, which camera can scan the inside of the cab. 
         [0069]    If there is a failure or other problem with any cab, with any sensor, with any camera, with any part of any shaft, with any other element of the system, or a conflict between any sensor or any camera, one or more alarms can be programmed to sound, and a human attendant can be instructed to immediately see what (if anything) is happening. The motions and functions of any cab can be manually controlled by a human attendant. 
         [0070]    The number, location and/or description of shafts, floors, zones, sections, sequential steps, elevator cabs, computers, computer programs, cameras and any other element of the invention can vary, as desired by the system operator. 
         [0071]    When sensors are referred to in any zone of any shaft, as described in the specification, this means and includes: 1) that all sensors are positioned in such zone; 2) that each sensor independently detects that such zone is empty; and 3) that each sensor is fully operational. 
         [0072]    Examples of the motions and changed positions of each cab in each shaft of a mid-rise structure will hereafter be described in sequential steps, in order to demonstrate and explain the control method and system, according to an embodiment of the present invention. 
         [0073]    Step 1. Cab V can load lower carpark passengers in zone B 2 . Cab U can load upper carpark passengers in zone B 1 . Cab T can load ground floor passengers in zone  1 . Cab T (the leading cab) can move up Shaft I to service passengers in the lower section of Shaft I. 
         [0074]    Step 2. After sensors in zone I indicate that leading Cab T has exited zone  1 , trailing Cab U can move up into zone  1  and load ground floor passengers. After sensors in zone B 1  indicate that Cab U has exited zone B 1 , trailing Cab V can move up into zone B 1  and continue loading carpark passengers. 
         [0075]    Step 3. After sensors in zone  10  indicate that leading Cab T has exited zone  10 , trailing Cab U can move up Shaft I and service passengers in the lower section of Shaft I. After sensors in zone  1  indicate that Cab U has exited zone  1 , trailing Cab V can move up into zone  1  and load ground floor passengers. 
         [0076]    Step 4. After sensors in zone  20  indicate that leading Cab T has exited zone  20 , trailing Cab U can move up into zone  11  and service passengers in the middle section of Shaft I. After sensors in zone  10  indicate that trailing Cab U has exited zone  10 , trailing Cab V can move up Shaft I and service passengers in the lower section of Shaft I. 
         [0077]    Step 5. When leading Cab T enters zone  30 , Cab T can unload all remaining passengers and then move directly up Shaft I into zone A 2  where it can stop. 
         [0078]    Step 6. After sensors in zone A 1  indicate that Cab T has exited zone A 1 , Cab U can move up into zone  21  and service passengers in the upper section of Shaft I. After Cab U enters zone  30 , Cab U can unload all remaining passengers on Floor  30  and move up into zone A 1  where it can stop. 
         [0079]    Step 7. At this approximate point in time, Cabs Q, R and S in Shaft II can begin to execute the aforementioned steps 1 through 6 in Shaft II. 
         [0080]    Step 8. After sensors in zone  20  of Shaft I indicate that Cab U has exited zone  20 , trailing Cab V can move up Shaft  1  into zone  11  and service passengers in the middle section of Shaft I. After sensors in zone  30  indicate that Cab U has exited zone  30 , trailing Cab V can move up into zone  21  and service passengers in the upper section of Shaft I. When trailing Cab V enters zone  30  it can unload all remaining passengers and stop. 
         [0081]    Step 9. After Cab V (the new leading cab) loads new down passengers on Floor  30 , Cab V can enter zone  29  and service passengers in the upper section of Shaft I. After leading Cab V exits zone  21 , Cab V can continue to move down Shaft I and service passengers in the middle section of Shaft I. 
         [0082]    Step 10. After sensors in zone  30  indicate that leading Cab V has exited zone  30 , trailing Cab U can move down Shaft  1  and enter zone  30  where it can load down passengers. After sensors in zone A 1  indicate that Cab U has exited zone A 1 , new trailing Cab T can move down into zone A 1  and wait. 
         [0083]    Step 11. After sensors in zone  21  indicate that leading Cab V has exited zone  21 , trailing Cab U can move down Shaft I and service passengers in the upper section of Shaft I. After sensors in zone  30  indicate that Cab U has exited zone  30 , trailing Cab T can move down into zone  30  and load down passengers. 
         [0084]    Step 12. At this approximate point in time, Cabs N, O and P in Shaft III can begin to execute the aforementioned steps 1 through 6 in Shaft III, and Cabs Q, R and S in Shaft II can begin to execute the aforementioned steps 8 through 11 in Shaft II. 
         [0085]    Step 13. After sensors in zone  11  of Shaft I indicate that leading Cab V has exited zone  11 , trailing Cab U can move down Shaft I into zone  20  and service passengers in the middle section of Shaft I. After sensors in zone  21  indicate that Cab U has exited zone  21 , trailing Cab T can move down Shaft I into zone  29  and service passengers in the upper section of Shaft I. 
         [0086]    Step 14. After leading Cab V moves into zone  10 , Cab V can continue to move down Shaft I and service passengers in the lower section of Shaft I. After Cab V exits zone  1  it can move down Shaft I to lower carpark zone B 2  where it can stop and load and unload passengers. 
         [0087]    Step 15. After sensors in zone  1  of Shaft I indicate that leading Cab V has exited zone  1 , trailing Cab U can move down into zone  10  and service passengers in the lower section of Shaft I. After sensors in zone  11  indicate that Cab U has exited zone  11 , trailing Cab T can move down Shaft I into zone  20  and service passengers in the middle section of Shaft I. 
         [0088]    Step 16. After sensors in zone B 1  indicate that Cab V has exited zone B 1 , Cab U can move down Shaft I into upper carpark zone B 1  where it can stop and load and unload passengers. After sensors in zone  1  indicate that Cab U has exited zone  1 , trailing Cab T can move down into zone  10  and service passengers in the lower section of Shaft I. When Cab T stops in zone  1 , Cab T can unload all remaining passengers and wait to load new up passengers. 
         [0089]    Step 17. At this approximate point in time, elevator Cabs Q, R and S in Shaft II, and elevator Cabs N, O and P in Shaft III, can continue to execute their remaining previously mentioned sequential steps in Shaft II and Shaft III respectively, while Cabs T, U and V in Shaft I can begin to execute their previously mentioned sequential steps 1 through 6 again. Once a cycle of sequential steps is completed in a mid-rise structure, this process can be continuously repeated all over again, until it is terminated by a computer or by a human attendant. 
         [0090]    When elevator cabs in Shaft I, Shaft II, and Shaft III in a mid-rise structure all operate together in sequence, their traffic pattern can become circular. Thus, there are always elevator cabs moving up in a shaft in sequence when other elevator cabs in other shafts are moving down in sequence. Therefore, no passenger in a mid-rise structure must wait very long to be serviced by an elevator cab moving up or down in sequence. 
         [0091]    A view from the front of an embodiment of four multi-cab elevator shafts (I, II, III and IV) in a 90-floor high-rise structure is illustrated in  FIG. 4 . Each Shaft can be divided into four sections: a lower section, a lower middle section, an upper middle section, and an upper section. Each floor of each shaft can represent a zone in which cabs in that shaft may be positioned. Each zone in each shaft can be designated by a number and/or a letter located next to each zone. The direction that each cab can move in each shaft can be indicated by the word ‘up’ above each shaft, and by the word ‘down’ below each shaft. At the bottom of each shaft there can be three carpark zones (B 1 , B 2 , and B 3 ), and at the top of each shaft there can be three attic zones (A 1 , A 2 , and A 3 ). 
         [0092]    In the bottom four zones of Shaft I there can be four elevator cabs respectively designated by the letters J, K, L and M. Cab M can be positioned in zone B 3 , Cab L can be positioned in zone B 2 , Cab K can be positioned in zone B 1 , and Cab J can be positioned in zone  1 . In the bottom four zones of Shaft II there can be four other elevator cabs respectively designated by the letters F, G, H, and I. Cab I can be positioned in zone B 3 , Cab H can be positioned in zone B 2 , Cab G can be positioned in zone B 1 , and Cab F can be positioned in zone  1 . In the bottom four zones of Shaft III there can be four other elevator cabs respectively designated by the letters B, C, D, and E. Cab E can be positioned in zone B 3 , Cab D can be positioned in zone B 2 , Cab C can be positioned in zone B 1 , and Cab B can be positioned in zone  1 . In the bottom four zones of Shaft IV there can be four other elevator cabs respectively designated by the letters A, Λ, Π, and Ω (the last three are letters in the Greek alphabet). Cab Ω can be positioned in zone B 3 , Cab Π can be positioned in zone B 2 , Cab Λ can be positioned in zone B 1 , and Cab A can be positioned in zone  1 . 
         [0093]    There can be one or more electronic sensors located in each zone of each shaft. Electronic sensors on the top and bottom of each cab can detect the distance between cabs and the speed of closure or separation between cabs. If the distance between cabs becomes too close for the speed of closure, a computer and/or an elevator governor can apply breaks to slow a cab down to a safe speed or distance. Each sensor can be connected to a central computer which can be programmed to control all of the motions and functions of each elevator cab in a high-rise structure. Sensors can also be mechanical sensors or other types of sensors, such as laser sensors. 
         [0094]    Each cab can have a video camera located on the top and on the bottom of the cab. Each video camera can be focused on the shaft in each direction of the cab&#39;s motion through the shaft. Each sensor can have a video camera focused on the zone of its responsibility. All sensors and video cameras can be connected to computer screens in the central operations room of the elevator system. Each cab can also have a video camera mounted on the inside center of the cab&#39;s ceiling which video camera can scan the inside of the cab. 
         [0095]    If there is a failure or other problem with any cab, with any sensor, with any camera, with any part of any shaft, with any other element of the system, or a conflict between any sensor or any camera, one or more alarms can be programmed to sound, and a human attendant can be instructed to immediately see what (if anything) is happening. The motions and functions of any cab can be manually controlled by a human attendant. 
         [0096]    The number, location and/or description of shafts, floors, zones, sections, sequential steps, elevator cabs, computers, computer programs, cameras and any other element of the invention can vary, as desired by the system operator. 
         [0097]    When sensors are referred to in any zone of any shaft, as described in the specification, this means and includes: 1) that all sensors are positioned in such zone; 2) that each sensor independently detects that such zone is empty; and 3) that each sensor is fully operational. 
         [0098]    Examples of the motions and changed positions of each cab in each shaft of a high-rise structure will hereafter be described in sequential steps, in order to demonstrate and explain the control method and system, according to an embodiment of the present invention. 
         [0099]    Step 1. In Shaft I, Cab M can load carpark passengers in zone B 3 ; Cab L can load carpark passengers in zone B 2 ; Cab K can load carpark passengers in zone B 1 ; Cab J can load passengers on the ground floor of a high-rise structure in zone  1 . 
         [0100]    Step 2. Cab J (the leading cab) can then move up Shaft I and service passengers in the lower section of Shaft I. After sensors in zone  1  indicate that Cab J has exited zone  1 , trailing Cab K can move up Shaft I into zone  1  and load ground floor passengers. After sensors in zone B 1  indicate that Cab K has exited zone B 1 , trailing Cab L can move up Shaft I into zone B 1  and continue loading carpark passengers. After sensors in zone B 2  indicate that Cab L has exited zone B 2 , trailing Cab M can move up Shaft I into zone B 2  and continue loading carpark passengers. 
         [0101]    Step 3. When leading Cab J exits zone  20 , Cab J can move up into zone  21  and service passengers in the lower middle section of Shaft I. After sensors in zone  20  indicate that leading Cab J has exited zone  20 , trailing Cab K can move up into zone  1  and load ground floor passengers. Cab K can then move up Shaft I to service passengers in the lower section of Shaft I. After sensors in zone B 1  indicate that Cab K has exited zone B 1 , trailing Cab L can move up into zone B 1  and continue loading carpark passengers. After sensors in zone B 2  indicate that Cab L has exited zone B 2 , trailing Cab M can move up into zone B 2  and continue loading carpark passengers. 
         [0102]    Step 4. When leading Cab J exits zone  41 , Cab J can move up into zone  42  and service passengers in the upper middle section of Shaft  1 . After sensors in zone  41  indicate that Cab J has exited zone  41 , trailing Cab K can move up into zone  21  and service passengers in the lower middle section of Shaft  1 . After sensors in zone  1  indicate that Cab L has exited zone  1 , trailing Cab M can move up into zone  1  and load ground floor passengers. 
         [0103]    Step 5. At this approximate point in time, Cabs F, G, H and I in Shaft II of a high-rise structure can begin to execute the aforementioned steps 1 through 4 in Shaft II of a high-rise structure. 
         [0104]    Step 6. When leading Cab J exits zone  62 , Cab J can move up into zone  63  and service passengers in the upper section of Shaft I. After sensors in zone  62  indicate that Cab J has exited zone  62 , trailing Cab K can move up into zone  42  and service passengers in the upper middle section of Shaft I. After sensors in zone  41  indicate that Cab K has exited zone  41 , trailing Cab L can move up into zone  21  and service passengers in the lower middle section of Shaft I. After sensors in zone  20  indicate that Cab L has exited zone  20 , trailing Cab M can move up from zone  1  and service passengers in the lower section of Shaft I. 
         [0105]    Step 7. When leading Cab J enters zone  84 , Cab J can unload all remaining passengers and then move directly up into zone A 3  where it can stop. After sensors in zone  84  indicate that Cab J has exited zone  84 , trailing Cab K can move up into zone  63  and service passengers in the upper section of Shaft I. When Cab K enters zone  84  Cab K can unload all remaining passengers and then move directly up into zone A 2  where it can stop. 
         [0106]    Step 8. After sensors in zone  84  indicate that Cab K has exited zone  84 , trailing Cab L can move up into zone  63  and service passengers in the upper section of Shaft I. When Cab L enters zone  84  Cab L can unload all remaining passengers. After sensors in zone A 1  indicate that Cab K has exited zone A 1 , trailing Cab L can move directly up into zone A 1  where it can stop. 
         [0107]    Step 9. After sensors in zone  41  indicate that Cab L has exited zone  41 , trailing Cab M can move up into zone  21  and service passengers in the lower middle section of Shaft I. After sensors in zone  62  indicate that Cab L has exited zone  62 , trailing Cab M can move up into zone  42  and service passengers in the upper middle section of Shaft I. After sensors in zone  84  indicate that Cab L has exited zone  84 , trailing Cab M can move up into zone  63  and service passengers in the upper section of Shaft I. When Cab M moves into zone  84 , Cab M can unload all remaining passengers and load new passengers who desire to move down Shaft I. 
         [0108]    Step 10. At this approximate point in time, Cabs B, C, D and E in Shaft III can begin to execute the aforementioned steps 1 through 4 in Shaft III of a high-rise structure, and Cabs F, G, H and I in Shaft II can begin to execute the aforementioned steps 6 through 9 in Shaft II of a high-rise structure. 
         [0109]    Step 11. When Cab M (the new leading cab in Shaft I) exits zone  84 , it can move down Shaft I and service passengers in the upper section of Shaft I. After sensors in zone  84  indicate that leading Cab M has exited zone  84 , new trailing Cab L can move down into zone  84  and load down passengers. After sensors in zone A 1  indicate that Cab L has exited zone A 1 , new trailing Cab K can move down into zone A 1  and wait. After sensors in zone A 2  indicate that trailing Cab K has exited zone A 2 , new trailing Cab J can move down into zone A 2  and wait. 
         [0110]    Step 12. When leading Cab M exits zone  63 , Cab M can continue moving down Shaft I and service passengers in the upper middle section of Shaft I. After sensors in zone  63  indicate that Cab M has exited zone  63 , trailing Cab L can move down into zone  84  and service passengers in the upper section of Shaft I. After sensors in zone  84  indicate that Cab L has exited zone  84 , new trailing Cab K can move down into zone  84  and load down passengers. After sensors in zone A 1  indicate that trailing Cab K has exited zone A 1 , new trailing Cab J can move down into zone A 1  and wait. 
         [0111]    Step 13. When leading Cab M exits zone  42 , Cab M can continue moving down Shaft I and service passengers in the lower middle section of Shaft I. After sensors in zone  42  indicate that Cab M has exited zone  42 , trailing Cab L can move down into zone  62  and service passengers in the upper middle section of Shaft I. After sensors in zone  63  indicate that Cab L has exited zone  63 , trailing Cab K can move down into zone  83  and service passengers in the upper section of Shaft I. After sensors in zone  84  indicate that Cab K has exited zone  84 , trailing Cab J can move down into zone  84  and load down passengers. 
         [0112]    Step 14. When leading Cab M exits zone  21 , Cab M can continue down Shaft I and service passengers in the lower section of Shaft I. After sensors in zone  21  indicate that Cab M has exited zone  21 , trailing Cab L can move down into zone  41  and service passengers in the lower middle section of Shaft I. After sensors indicate that Cab L has exited zone  42 , trailing Cab K can move down into zone  62  and service passengers in the upper middle section of Shaft I. After sensors indicate that Cab K has exited zone  63 , trailing Cab J can move out of zone  84  and service passengers in the upper section of Shaft I. 
         [0113]    Step 15. At this approximate point in time, Cabs A, Λ, II, and Ω in Shaft IV can begin to execute the aforementioned steps 1 through 4 in Shaft IV of a high-rise structure; Cabs B, C, D and E in Shaft III can begin to execute the aforementioned steps 6 through 9 in Shaft III of a high-rise structure; and cabs F, G, H and I in Shaft II can begin to execute the aforementioned steps 11 through 14 in Shaft II of a high-rise structure. 
         [0114]    Step 16. When leading Cab M enters zone  1  of Shaft I, Cab M can unload passengers on the ground floor of a high-rise structure. Cab M can then move down into carpark zone B 1  and unload more passengers. After sensors in zone  1  indicate that leading Cab M has exited zone  1 , trailing Cab L can move down into zone  20  and service passengers in the lower section of Shaft  1 . When trailing Cab L enters zone  1 , Cab L can stop and unload passengers on the ground floor. After sensors in zone  21  indicate that Cab L has exited zone  21 , trailing Cab K can move down into zone  41  and service passengers in the lower middle section of Shaft I. After sensors in zone  42  indicate that Cab K has exited zone  42 , trailing Cab J can move down into zone  62  and service passengers in the upper middle section of Shaft I. 
         [0115]    Step 17. When leading Cab M finishes unloading passengers in carpark zone B 1  of Shaft I, Cab M can move down into carpark zone B 2  and unload more passengers. After sensors in zone B 1  indicate that Cab M has exited zone B 1 , trailing Cab L can exit ground floor zone  1  and move down into carpark zone B 1  and unload more passengers. After sensors in zone  1  indicate that Cab L has exited zone  1 , trailing Cab K can move down into zone  20  and service passengers in the lower section of Shaft I. When trailing Cab K enters zone  1 , Cab K can stop and unload passengers on the ground floor. After sensors in zone  21  indicate that Cab K has exited zone  21 , trailing Cab J can move down into zone  41  and service passengers in the lower middle section of Shaft I. 
         [0116]    Step 18. After leading Cab M has unloaded passengers in carpark zone B 2 , Cab M can move down into carpark zone B 3  where it can stop, and unload and load passengers. After sensors in zone B 2  indicate that Cab M has exited zone B 2 , trailing Cab L can move down into carpark zone B 2 , where it can stop, and unload and load passengers. After sensors in zone B 1  indicate that Cab L has exited zone B 1 , trailing Cab K can move out of zone  1  and down into carpark zone B 1  where it can stop and unload and load passengers. After sensors in zone  1  indicate that Cab K has exited zone  1 , trailing Cab J can move down into zone  20  and service passengers in the lower section of Shaft I. When trailing Cab J enters zone  1 , Cab J can stop and unload all down passengers. Cab J (the new leading cab) can then load new up passengers, and wait to start the next cycle of sequential steps. 
         [0117]    Step 19. At this approximate point in time, Cabs F, G, H, and I in Shaft II can begin to execute the aforementioned steps 16 through 18 in Shaft II of a high-rise structure; Cabs B, C, D, and E in Shaft III can begin to execute the aforementioned Steps 11 through 15 in Shaft III of a high-rise structure; Cabs A, Λ, Π, and Ω in Shaft IV can begin to execute the aforementioned steps 6 through 9 in Shaft IV of a high-rise structure; and Cabs J, K, L, and M in Shaft I can begin to execute the aforementioned steps 1 through 4 in Shaft I again. So the previous cycle of sequential steps repeats itself in the four shafts of a high-rise structure, and continues to repeat itself until the computer terminates such cycles, or they are terminated by a human attendant. 
         [0118]    Thus, when elevator cabs in Shaft I, Shaft II, Shaft III and Shaft IV in a high-rise structure all operate together in sequence, their traffic patterns become circular. There are always elevator cabs moving up shafts in sequence, while other elevator cabs in other shafts are moving down in sequence. Therefore no passenger in a high-rise structure must wait very long to be serviced by an elevator cab moving up or down. 
         [0119]    Each computer program of zones and sections for each elevator shaft can vary and be flexible. This can mean that zones and sections in each shaft can be changed to adapt to changing passenger traffic throughout each different 24 hour day and each different seven day week. For example, during the morning rush hours on a normal work day, one or more shafts may be programmed for passengers entering into a building, where each cab in a shaft can express from a designated lower floor up to a designated upper floor, then service a group of upper floors in that particular section of the shaft, and then express back down the shaft to a lower floor to load more passengers. After rush hours, the zones and sections in certain elevator shafts may be changed to accommodate more balanced normal up and down passenger traffic until lunch hours. During lunch hours, the zones and sections in certain shafts may be changed to accommodate different passenger traffic, and then change again after the lunch hours end. Thereafter, in order to accommodate late afternoon passengers who desire to exit the building, one or more shafts may be programmed for an exiting ‘express mode,’ where each elevator cab can service a group of upper floors and then express down the elevator shaft to the ground floor (or parking floors) where passengers can exit the building, and then expresses back up to a designated group of floors to load other passengers who desire to exit the building. Similarly, between 7 p.m. and 7 a.m. one or more elevator shafts may change its computer control program to ‘sleep mode,’ where only one or two cabs in one shaft operate in a building during the late evening and early morning hours. On weekends and holidays, a different computer program of zones and sections may be operated in a building or structure. 
         [0120]    This new elevator control system and method is at least as failsafe as any current elevator computer control system. The primary reason for this conclusion is that, unless or until one or more sensors positioned in a zone all independently indicate that such zone is empty, no trailing elevator cab can move into that zone. Therefore, no cabs in a multi-cab elevator shaft, whether leading cabs or trailing cabs, can ever have an opportunity to collide with each other. 
         [0121]    This control system is also not limited to vertical transportation, such as elevators. For example, it can be applied to control angular transportation such as a 45° degree inclined funicular railway containing multiple independently moving cabs. It can also be applied to horizontally moving cars or pods traveling independently along horizontal rails, or on a road, such as a group of driverless cars following each other through multiple zones. There may also be other applications for this control system, such as deep mines. 
         [0122]    Throughout the description and drawings, example embodiments are given with reference to specific configurations. It will be appreciated by those of ordinary skill in the art that the present invention can be embodied in other specific forms. Those of ordinary skill in the art would be able to practice such other embodiments without undue experimentation. The scope of the present invention, for the purpose of the present patent document, is not limited merely to the specific example embodiments or alternatives of the foregoing description.