Patent Publication Number: US-11383955-B2

Title: Elevator system control based on building and rope sway

Description:
BACKGROUND 
     Elevator systems are in widespread use for carrying passengers between various levels in buildings. Various factors affect elevator system operation at different times. For example, building sway conditions may introduce lateral movement of the roping of a traction-based elevator system. A variety of proposals have been made to control an elevator system in a way that should address such sway conditions. 
     One drawback associated with previous approaches is that the sensor devices that detect sway conditions tend to be expensive and provide limited information. Another issue associated with previous approaches is that they are not well-suited to address the more significant and potentially variable sway conditions that may be present in high rise and ultra-high rise buildings due to excessive building sway as an additional complication factor. 
     SUMMARY 
     An illustrative example elevator control system includes a plurality of sway sensors are situated within a hoistway of the building. The sway sensors respectively include a contact surface situated to be contacted by a vertically extending elongated member of an elevator when the elongated member moves laterally in the hoistway. The sway sensors respectively provide an indication of contact between the contact surface and the elongated member. A controller receives an indication of building movement and the indications from the sway sensors. The controller determines whether at least one condition exists in the hoistway based on the indications and implements an adjustment to elevator movement control when the at least one condition exists. 
     In an example embodiment having one or more features of the elevator control system of the previous paragraph, the condition in the hoistway comprises an undesirable amount or pattern of sway of the elongated member. 
     In an example embodiment having one or more features of the elevator control system of either of the previous paragraphs, the sway sensors are at respective, preselected vertical locations along the hoistway; and the controller uses information regarding the vertical location of any of the sway sensors that provides an indication of contact with the elongated member for determining whether the at least one condition exists. 
     In an example embodiment having one or more features of the elevator control system of any of the previous paragraphs, the contact surfaces of the sway sensors are moveable relative to a wall of the hoistway and the indication from each sway sensor includes an indication of movement of the contact surface in response to contact with the elongated member. 
     In an example embodiment having one or more features of the elevator control system of any of the previous paragraphs, the indication from each sway sensor includes an indication of at least one of a direction of movement of the contact surface, an amount of movement of the contact surface, a speed of movement of the contact surface, an acceleration of the contact surface, and a force incident on the contact surface associated with the movement of the contact surface. 
     In an example embodiment having one or more features of the elevator control system of any of the previous paragraphs, the controller determines a severity of a load transfer from the elongated member to the respective sway sensors. 
     In an example embodiment having one or more features of the elevator control system of any of the previous paragraphs, the sway sensors are at respective, preselected vertical locations along the hoistway; the controller determines the severity of the load transfer at each of the vertical location; and the controller determines whether the at least one condition exists based on the locations and severity of the load transfer. 
     In an example embodiment having one or more features of the elevator control system of any of the previous paragraphs, the sway sensors each comprise a roller, the contact surface of each sway sensor is a surface on the roller, the rollers each have an axis oriented at a selected angle relative to an adjacent hoistway wall, and the rollers are respectively supported to be moveable toward the adjacent hoistway wall in response to contact with the elongated member. 
     In an example embodiment having one or more features of the elevator control system of any of the previous paragraphs, the hoistway includes a plurality of walls and at least one of the rollers is aligned with each of the plurality of walls. 
     In an example embodiment having one or more features of the elevator control system of any of the previous paragraphs, the controller determines an amount or pattern of building sway from the indication of building movement, the controller determines an amount or pattern of elongated member sway from the sway sensors, and the controller determines whether the at least one condition exists based on the building sway and the elongated member sway. 
     In an example embodiment having one or more features of the elevator control system of any of the previous paragraphs, the at least one condition is one of a plurality of predetermined conditions, a first one of the predetermined conditions is different than a second one of the predetermined conditions, the controller implements a first adjustment when the first one of the predetermined conditions exists, and the controller implements a second adjustment that is different than the first adjustment when the second one of the predetermined conditions exists. 
     An example embodiment of an elevator system includes the elevator control system of any of the previous paragraphs and an elevator car. The elongated member comprises at least one of a traction rope suspending the elevator car, a traction belt suspending the elevator car, a compensation rope associated with the elevator car, and a travelling cable associated with the elevator car. 
     An illustrative example method of elevator control includes detecting lateral movement of a vertically extending elongated member of the elevator using a plurality of sway sensors situated within a hoistway of the building, determining whether at least one condition exists in the hoistway based on an indication of building movement and the detected lateral movement of the elongated member, and implementing an adjustment to elevator movement control when the at least one condition exists. 
     In an example embodiment having one or more features of the method of the previous paragraph, the condition in the hoistway comprises an undesirable amount or pattern of sway of the elongated member. 
     An example embodiment having one or more features of the method of any of the previous paragraphs includes determining vertical locations along the hoistway where the detected lateral movement occurs and determining whether the at least one condition exists based on the vertical locations. 
     In an example embodiment having one or more features of the method of any of the previous paragraphs, the respective sway sensors provide an indication of a reaction of the sway sensor to contact with the elongated member. The indication includes an indication of least one of a direction of movement of the sway sensor, an amount of movement of the sway sensor, a speed of movement of the sway sensor, an acceleration of the sway sensor, and a force incident on the sway sensor. The method also includes determining a severity of a load transfer from the elongated member to the respective sway sensors. 
     An example embodiment having one or more features of the method of any of the previous paragraphs includes determining the severity of the load transfer at each of a plurality of vertical locations along the hoistway and determining whether the at least one condition exists based on the locations and severity of the load transfer. 
     An example embodiment having one or more features of the method of any of the previous paragraphs includes determining an amount or pattern of building sway from the indication of building movement, determining an amount or pattern of elongated member sway from the sway sensors, and determining whether the at least one condition exists based on the building sway and the elongated member sway. 
     In an example embodiment having one or more features of the method of any of the previous paragraphs, the at least one condition is one of a plurality of predetermined conditions and a first one of the predetermined conditions is different than a second one of the predetermined conditions. The method also includes implementing a first adjustment when the first one of the predetermined conditions exists, and implementing a second adjustment that is different than the first adjustment when the second one of the predetermined conditions exists. 
     An example embodiment of an elevator system includes a controller configured to implement the method of any of the previous paragraphs and an elevator car. The elongated member comprises at least one of a traction rope suspending the elevator car, a traction belt suspending the elevator car, a compensation rope associated with the elevator car, and a travelling cable associated with the elevator car. 
     The various features and advantages of an example embodiment will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates selected portions of an elevator system and building sway. 
         FIG. 2  schematically illustrates an example sway sensor. 
         FIG. 3  is a schematic, cross-sectional horizontal view of an example arrangement of sway sensors within a hoistway. 
         FIG. 4  is a flow chart diagram summarizing an example control technique based on a building sway condition. 
     
    
    
     DETAILED DESCRIPTION 
     Selected portions of an elevator system  20  are schematically illustrated in  FIG. 1 . The elevator system  20  includes an elevator car  22  situated within a hoistway  24  of a building  26 . The hoistway  24  may be situated in a variety of locations within the building  26 , depending on the building configuration. 
     The example elevator system  20  is a traction-based system in which the elevator car  22  is suspended by a traction roping assembly  28 , which may comprise round steel ropes or flat belts. Other aspects of the elevator system, which are known to those skilled in the art, are not illustrated such as a counterweight, compensation roping and a traveling cable. The individual ropes or belts of the traction roping assembly  28  are example types of vertically extending elongated members of the elevator system  20 . The compensation roping and traveling cable (not illustrated) are other examples of elongated members. For discussion purposes, the elongated members of the traction roping assembly  28  are discussed below and, as those skilled in the art will appreciate, the issues pertaining to those elongated members may apply equally to other elongated members in the elevator system  20 . 
     As schematically shown in  FIG. 1 , the building  26  moves in response to environmental conditions such as wind or an earthquake or non-uniform temperature distribution in the building. When the building  26  is a high rise or ultra-high rise building such movement will likely occur as a result of less stimulus and typically will include a larger extent or amount of movement. The illustrated example system includes building sensors  30  that detect movement of the building  26  and provide an output including an indication of the movement. Building sensor outputs may include quantitative indications regarding an amount or extent of movement, qualitative indications, (i.e., an indication of at least some movement or a measured reaction that is above or below a threshold), or a combination of quantitative and qualitative indications. The building sensors  30  in some embodiments comprise vibration sensors, accelerometers or strain gages. In other embodiments the building sensors  30  comprise gyroscopes, pendulums, video cameras or infrared imaging devices. Those skilled in the art who have the benefit of this description will be able to select appropriate building sensor devices for their particular situation. 
     In the situation represented in  FIG. 1 , the building  26  is swaying from side to side. When that occurs, the hoistway  24  also moves from side to side from a centered or rest position shown in broken lines in the middle of  FIG. 1  to the positions or orientations shown on the right and left, respectively. When the hoistway  24  is in the centered or rest position, the elongated members of the traction roping assembly  28  are typically vertical and follow a path of movement that is unhindered. When the building  26  and the hoistway  24  move as illustrated, however, the elongated members of the traction roping assembly  28  move laterally away from a true vertical or design orientation. In some cases, the elongated members may move far enough laterally to contact the walls of the hoistway  24  or other elevator system components within the hoistway  24 . 
     The illustrated example system  20  includes sway sensors  32  situated within the hoistway  24 . The sway sensors  32  include a contact surface situated to be contacted by an elongated member of the traction roping assembly  28  if the elongated member moves sufficiently laterally to make such contact. The sway sensors  32  provide an output including an indication of such contact. 
     A controller  34  receives the indications from the building sensors  30  and the sway sensors  32 . The communications between the sensors  30 ,  32  and the controller  34  may be wireless, line-based or part of a local or globally-integrated Internet of Things communication network. The controller  34  uses the indications from the sensors  30 ,  32  to determine whether a condition exists within the hoistway  24  that warrants adjusting control over movement of the elevator car. For example, the condition may include an amount or pattern or elongated member sway within the hoistway  24  that should be addressed by adjusting control of the elevator system movement. Another condition may include an amount or pattern of building sway. In the illustrated example, the controller  34  has access to information regarding a plurality of predetermined possible conditions and sensor indications corresponding to such conditions so that the controller  34  is capable of identifying when one or more of those conditions exist. 
     The controller  34  also has information or programming so that the controller  34  determines an appropriate adjustment to elevator car movement control to address the current condition or conditions. For example, some sway frequencies will correspond to a resonant frequency of the elongated members of the roping assembly  28  if the elevator car  22  is at certain locations along the hoistway  24 . The controller  34  determines when such sway conditions exist and controls movement of the elevator car  22  to avoid being in those locations, which may be considered critical zones because it is desirable to avoid rope or belt sway at a resonant frequency. 
       FIGS. 2 and 3  schematically show features of example sway sensors  32 . In this example, the sway sensors  32  include bumpers  36  that are situated near the walls of the hoistway  24 . The bumpers  36  each include a contact surface facing toward the interior of the hoistway  24 . The bumpers  36  provide some cushion or protection for the elongated member in the event of contact between them. The bumpers  36  also protect the elongated member from contacting the hoistway wall. The bumpers  36  may be designed as cylindrical or almost cylindrical rollers to minimize potential shear sliding between the elongated member and the contact surface of the bumpers. In some embodiments, the bumpers  36  comprise idler rollers that have effectively no resistance against rotation. 
     The example bumpers  36  comprise rollers that are situated so an axis of rotation A of each roller is parallel to an adjacent wall of the hoistway  24 . A support structure  38  positions the bumper  36  away from the wall of the hoistway  24 . In the illustrated example, the support structure  38  allows some movement of the bumper  36  toward the adjacent hoistway wall in response to contact with the elongated member. The sway sensors  32  provide an indication of such movement by indicating at least one of a direction of such movement, an amount of such movement, a speed of such movement, acceleration during such movement, and a force associated with such movement. In some embodiments the controller  34  determines one or more of such features of such movement. 
     In some embodiments the bumpers  36  do not move relative to the hoistway walls but do deflect or deform in response to contact with an elongated member. In those embodiments, the sway sensors  32  are configured to provide an indication of such contact based on the resulting deflection or deformation. 
     One aspect of the sway sensors  32  is that they are respectively situated at preselected and known vertical locations along the hoistway  24 . The controller  34  determines a reaction R ij  of each sway sensor  32  to contact with an elongated member and the location of that reaction. In this example, i corresponds to the vertical position or location in the building and j corresponds to the orientation of the reaction. The reaction is based on the indication of movement, deflection, load or a combination of them provided by the sway sensors  32 . Based on those reactions and their respective locations, the controller  34  determines a severity of load transfer from the elongated member(s) to the sway sensors  32 . That load transfer information is useful for the controller  34  to determine how to adjust control over the movement of the elevator car  22 . 
     An example control strategy implemented by the controller  34  is summarized in the flow chart diagram  40  of  FIG. 4 . At  42  the building sensors  30  detect movement of the building  26 . The building sensors  30  respectively provide an indication of the movement of a portion of the building  26  that is situated in a location corresponding to the building sensor  30  location. At  44 , the sway sensors  32  detect lateral movement of the elongated member(s). The controller  34  receives the indications from the building sensors  30  and the sway sensors  32  and determines, at  46 , whether at least one condition exists in the hoistway  24  based on the detected building movement and the detected lateral movement of the elongated member. 
     Determining whether at least one condition exists at  46  in some embodiments is based on information available to the controller  34  regarding known or expected characteristics of building or elongated member movement corresponding to a set of sensor indications. For example, the controller  34  is programmed or otherwise configured to analyze quantifiable correlations between sensor indications and movement of the building  26  or elongated members of the elevator system  20 . 
     Some example controller  34  embodiments utilize information regarding theoretical predictions developed according to established methods of structural analysis and known features or characteristics of the building  26  and the elevator system  20 . Other embodiments include empirical predictions based on direct measurements from the sensors  30  and  32  and quantified correlations of such measurements and actual building or elongated member movement. Some embodiments include a machine learning approach for correlating measured or detected movement and resulting conditions within the hoistway  24 . Some embodiments include combinations of any two or more of the above-noted analytical (e.g., based on predictive methods of structural analysis), empirical (e.g., based on direct measurements) and machine learning based approaches. Those skilled in the art who have the benefit of this description will be able to select an appropriate approach for their particular implementation. 
     One way in which the disclosed example embodiment improves on detecting sway conditions and controlling elevator system movement is that it combines information regarding building movement and elongated member movement for determining what conditions exist in the hoistway. Since building movement and elongated member movement can contribute to resulting conditions in the hoistway in different manners under different combinations of such movements, the illustrated system provides more versatility and accuracy over elevator movement control. 
     Another improvement over previous sway detection arrangements is based on the plurality of sway sensors  32  situated along the hoistway. The sway sensors  32  may be strategically placed where the most significant lateral movement of the elongated members is expected to protect the components of the elevator system while also providing indications of the most significant load transfer. 
     The illustrated embodiment also provides the ability to assess building integrity and any potential changes to the structural components of the elevator system. 
     Elevator system control consistent with the disclosed example embodiment provides more specific and effective control over the position, movement or both of the elevator based upon characteristics of a condition within the hoistway. Such response to particular characteristics of building movement and elongated member movement improves the ability to maintain a desired condition of elevator system components and achieve a desired elevator system performance. 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.