Abstract:
A conveyor system including a conveyor belt; a conveyor rail including a track having a proximal end and a distal end, and a conveyor take-up for collecting excess conveyor belt; a conveyor carriage configured to move along the track between the proximal end and the distal end, the conveyor carriage including a base rotatably supporting the conveyor belt, and a target; a winch positioned proximate the proximal end of the track, the winch including a carriage cable coupling the conveyor carriage to the winch, a motor, and a motor sensor configured to sense a motor characteristic; a position sensor configured to sense a position of the target; and a controller having a memory and processor. The controller is configured to receive the motor characteristic and the position of the target, calculate a characteristic of the conveyor system, and output the characteristic.

Description:
RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Application No. 61/818,327, filed May 1, 2013, the entire contents of which are hereby incorporated. 
    
    
     BACKGROUND 
     The present invention relates to position monitoring for conveyor belts used in the mining industry. 
     Position monitoring for conveyor belts is typically performed using incremental end coders that count turns of a motor shaft of the winch. The turns of the motor shaft provide an estimated position of a conveyor carriage, and thus an estimated length of conveyor belt in a belt storage unit (i.e., take-up unit). However, the use of incremental end coders is inaccurate and must be reset every time a power outage occurs. 
     SUMMARY 
     In one embodiment, the invention provides a conveyor system including a conveyor belt, a conveyor rail, a conveyor carriage, a winch, a position sensor, and a controller. The conveyor rail includes a track, the track having a proximal end and a distal end, and a conveyor take-up for collecting excess conveyor belt. The conveyor carriage is configured to move along the track between the proximal end and the distal end. The conveyor carriage includes a base, the base rotatably supporting the conveyor belt, and a target. The winch is positioned proximate the end of the track. The winch includes a carriage cable coupling the conveyor carriage to the winch, a motor, and a motor sensor configured to sense a motor characteristic. The position sensor is configured to sense a position of the target. The controller includes a memory and a processor and is configured to receive the motor characteristic and the position of the target, calculate a characteristic of the conveyor system, and output the characteristic. 
     In another embodiment the invention provides a method of monitoring a conveyor system including a conveyor belt, a conveyor rail having a proximal end and a distal end, a conveyor carriage configured to move along the conveyor rail between the proximal end and the distal end, a winch having a motor, and a position sensor. The method including receiving a position of the conveyor carriage on the conveyor rail; receiving a rotational speed and a rotational direction of the motor; calculate a characteristic of the conveyor system, the characteristic based on the position of the conveyor carriage, the rotational speed of the motor, and the rotational direction of the motor; and output the characteristic of the conveyor system. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a side view of a conveyor system. 
         FIG. 2  illustrates a top view of the conveyor system of  FIG. 1 . 
         FIG. 3  illustrates a control system of the conveyor system shown in  FIGS. 1 and 2 . 
         FIG. 4  is a flowchart illustrating operation of the conveyor system shown in  FIGS. 1 and 2 . 
         FIG. 5  illustrates a user-interface of the conveyor system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect. Also, electronic communications and notifications may be performed using any known means including direct connections, wireless connections, etc. 
     It should also be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components may be used to implement the invention. In addition, it should be understood that embodiments of the invention may include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic based aspects of the invention may be implemented in software (e.g., stored on non-transitory computer-readable medium) executable by one or more processors. As such, it should be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components may be utilized to implement the invention. Furthermore, and as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify embodiments of the invention and that other alternative mechanical configurations are possible. For example, “controllers” described in the specification can include standard processing components, such as one or more processors, one or more computer-readable medium modules, one or more input/output interfaces, and various connections (e.g., a system bus) connecting the components. 
       FIGS. 1 and 2  illustrate a conveyor system  100 . In one embodiment, the conveyor system  100  is used in underground mining operations. In some embodiments, the conveyor system  100  is used in conjunction with longwall mining. The conveyor system  100  transports mined material (e.g., coal, ore, rock, etc.), via a conveyor belt  105 , through a mine. During transportation of the mined material, the conveyor belt  105  must maintain a constant proper tension. 
     The conveyor system  100  includes a conveyor rail system  110 , a conveyor carriage system  115 , and a winch system  120 . The conveyor rail system  110 , the conveyor carriage system  115 , and the winch system  120  help maintain the conveyor belt  105  at a proper tension. 
     The conveyor rail system  110  extends along a wall of the mine. The conveyor rail system  110  includes a proximal end  200 , a distal end (not shown), a conveyor take-up  205 , and rail tracks  210 . The conveyor take-up  205  collects excess conveyor belt  105 . The conveyor take-up  205  further allows excess conveyor belt  105  out. In some embodiments, the conveyor take-up  205  includes a plurality of take-up pulleys. In such an embodiment, the conveyor belt  105  is lapped around the plurality of take-up pulleys. In the illustrated embodiment, the conveyor take-up  205  is a horizontal take-up. In another embodiment, the conveyor take-up  205  is a gravity take-up. In yet another embodiment, the conveyor take-up  205  is a vertical take-up. The rail tracks  210  provide a track for the conveyor carriage system  115 . 
     In one embodiment, the conveyor carriage system  115  includes carriage wheels  250 , a carriage base  255 , and a drive sprocket  260 . The carriage wheels  250  support the carriage base  255 , and are operable to allow movement of the conveyor carriage system  115  along the rail tracks  210 . The drive sprocket  260  is connected to the carriage base  255 . The drive sprocket  260  is coupled to a drive sprocket motor (not shown). The drive sprocket motor rotates the drive sprocket  260 . As the drive sprocket  260  is rotated, the conveyor belt  105  is driven in a desired direction for transporting the mined material. 
     In another embodiment, rather than the drive sprocket  260 , the conveyor carriage system  115  includes an idler, or idle pulley. In such an embodiment, the idler in is contact with the conveyor belt  105 . The idler freely rotates as the conveyor belt  105  is driven. 
     The winch system  120  is located adjacent to the proximal end  200  of the conveyor rail system  110 . The winch system  120  maintains a constant connection with the carriage base  205  via a carriage cable  300 . The winch system  120  includes a winch base  305 , a winch  310 , and a winch motor  315 . The winch base  305  supports the winch  310  and winch motor  315 . The carriage cable  300  is let-out or wound-up, by the winch  310 . 
     During operation, the winch  310  winds-up the carriage cable  300 . As the carriage cable  300  is wound-up, the conveyor carriage system  115  moves in a first direction  350 , toward the winch system  120 . As the conveyor carriage system  115  moves in the first direction  350 , excess conveyor belt  105  is stored in the conveyor belt take-up  205 , resulting in greater tension of the conveyor belt  105 . 
     When less tension of the conveyor belt  105  is needed, the winch  310  lets-out the carriage cable  300 . As the carriage cable  300  is let-out, the conveyor carriage system  115  is allowed to move in a second direction  355 , away from the winch system  120 . As the conveyor carriage system  115  moves in the second direction  355 , conveyor belt  105  is let out of the conveyor belt take-up  205 . 
       FIG. 3  illustrates a monitoring system  400  for monitoring various aspects of the mining system  100 . The monitoring system  400  includes a controller  405 , a user-interface  410 , a position sensor  415 , and a winch motor sensor  420 . In other embodiments, the monitoring system  400  includes more or less components. The controller  405  includes a processor  425  and a memory  430 . The memory  430  stores instructions executable by the processor  425  and various inputs/outputs for, e.g., allowing communication between the controller  405  and the operator or between the controller  405  and the various sensors. In some instances, the controller  405  includes one or more of a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or the like. 
     The user-interface  410 , such as an operator user-interface, provides information to the operator (e.g., the status of the mining system  100 , characteristics of the mining system  100 , etc.). The user-interface  410  includes one or more of the following: a display (e.g., a liquid crystal display (LCD)); one or more light emitting diodes (LEDs) or other illumination devices; a heads-up display; speakers for audible feedback (e.g., beeps, spoken messages, etc.); tactile feedback devices such as vibration devices; or another feedback device. 
     The controller  405  is in communication with the position sensor  415 . In some embodiments, the position sensor  415  is an ultrasonic sensor, such as but not limited to, a DME4000 Distance Measuring Sensor by Rockwell Collins. The position sensor  415  continually senses a distance between the conveyor carriage system  115  and the winch system  120 . In some embodiments, the position sensor  415  is located on the winch base  305  of the winch system  120 . The position sensor  415  acts as both an output and an input for a signal  435  ( FIGS. 1 and 2 ). In some embodiments, the signal  435  is an ultrasonic signal (e.g., a laser signal). The signal  435  is reflected off of a target  440  located on the conveyor carriage system  115  (e.g., the conveyor base  225 ). In some embodiments, the target  440  is a minimum of six inches by six inches. The travel time of the signal  435  reflected off of the target  440  is used to determine a distance between the position sensor  415  and the target  440 . This distance between the position sensor  415  and the target  440  is directly related to the distance between the winch system  120  and the conveyor carriage system  115 . 
     In operation, the position sensor  415  outputs the signal  435  towards the target  440 . The signal  435  is reflected off of the target  440  back towards the position sensor  415 . The position sensor  415  receives the reflected signal  435 . The position sensor  415  calculates the travel time of the signal  435  travelling to the target  440 , reflecting off the target  440 , and travelling back to the position sensor  415 . The position sensor  415  calculates the distance (i.e., position of the target  440 ) by using the relationship with time: Distance=½ (Speed×Time), where speed is equal to the speed of light (i.e., 300,000 km/s). The position sensor  415  sends the calculated distance (i.e., position) to the controller  405 . 
     The controller  405  determines the travelling speed (i.e., velocity) of the conveyor carriage system  115 , and the direction of the movement, as the conveyor carriage system  115  moves toward or away from the winch system  120 . The controller  405  determines the travelling speed from two or more calculated distances received from the position sensor  415 , along with difference in time between the calculated distances. The travelling speed is calculated using the following equation: Speed=(Distance 2 −Distance 1 )/(Time 2 −Time 1 ). 
     The controller  405  is in further communication with the winch motor sensor  420 . The winch motor sensor  420  monitors characteristics of the winch motor  315 , such as but not limited to, the rotational speed of the winch motor  315  and the rotational direction of the winch motor  315 . In some embodiments the winch motor sensor  420  is a magnetic sensor (e.g., a hall effect sensor). In other embodiments, the winch motor sensor  420  is a current sensor, an optical sensor, or another type of motor sensor. The winch motor sensor  420  outputs the sensed rotational speed and the sensed rotational direction of the winch motor  315  to the controller  405 . 
     In operation, the controller  405  calculates characteristics of the mining system  100  based on the position of the target  440  and/or the characteristics of the winch motor  315 . The characteristics of the mining system  100  may include, but are not limited to, operational and mechanical issues of the conveyor system  100 . For example, but not limited to, the controller  405  is operable to detect if the conveyor belt  105  breaks, detect if the carriage cable  300  breaks, and monitor if there are control problems over the mining system  100 . 
       FIG. 4  illustrates an operation  500  for determining a mechanical issue of the conveyor system  100 . The controller  405  receives the rotational speed of the winch motor  315  from the winch motor sensor  420  (Step  505 ). The controller  405  calculates the travelling speed of the conveyor carriage system  115  from the received positions of the conveyor carriage system  115  (Step  510 ). The controller  405  determines if the rotational speed has reached a predefined maximum rotational speed (Step  515 ). If the rotational speed has not reached the predefined maximum rotational speed, the operation continues to Step  505 . If the rotational speed has reached the predefined maximum rotational speed, the controller  405  determines if the travelling speed has reached a predefined maximum travelling speed (Step  520 ). If the travelling speed has not reached the predefined maximum travelling speed, the operation continues to Step  505 . If the travelling speed has reached the predefined maximum travelling speed, the controller  405  determines if the rotation of the winch motor  315  and the travelling direction of the conveyor system  110  are in the same direction (Step  525 ). If the movement of the winch motor  315  and the movement of the conveyor carriage system  115  are in the same direction, the controller  405  determines that the conveyor belt  105  has broken (Step  530 ). If the movement of the winch motor  315  and the movement of the conveyor carriage system  115  are not in the same direction, the controller  405  determines that the carriage cable  300  has broken (Step  535 ). 
     In one embodiment, if the controller  405  determines that there has been an operational or mechanical issue with the conveyor system  100  or abnormal operation of the conveyor system  100 , the controller  405  shuts down the conveyor system  100 . In another embodiment, if the controller  405  determines that there has been an operational or mechanical issue with the conveyor system  100 , the controller  405  outputs an alert to an operator via the user-interface  410 . An operational or mechanical issue may include, but is not limited to, a broken conveyor belt  105 , a broken carriage cable  300 , a misalignment of the position sensor  415 , a misalignment of the target  440 , an over-speed condition of the winch  310  (e.g., during pay-in operations or pay-out operations), encoder speed errors, and abnormal operation of the conveyor system  100  (e.g., abnormal operation of the winch  310 , unstable conveyor belt  105 , etc.). In some embodiments the controller  405  determines if there has been abnormal operation of the conveyor system  100  by comparing real-time velocity values of the winch motor  315  and/or the conveyor carriage system  115  with standard velocity models. Variations between the real-time velocities and the standard velocity models may indicate an abnormal operation of the conveyor system  100 . For example, if a conveyor belt  105  is unstable, the conveyor belt  105  produces oscillations. These oscillations can be detected by the controller  405  by analyzing variations between the real-time velocities and the standard velocity models. 
       FIG. 5  illustrates an embodiment of user-interface  410 . In the illustrated embodiment, the controller  405  outputs a plurality of characteristics  600  of the conveyor system  100 . The plurality of characteristics  600  may include, but are not limited to, a capacity of take-up  605 , a velocity  610  of the conveyor carriage system  115 , an amount  615  of the conveyor belt  105  remaining in the conveyor take-up  205 , and a distance  620  that the conveyor carriage system  115  will travel before the conveyor take-up  205  is full. 
     In another embodiment, the controller  405  is further in communication (e.g., wired communication or wireless communication) with a network. In such an embodiment, the controller  405  outputs the characteristics of the mining system  100  to the network for further analysis. 
     Thus, the invention provides, among other things, position monitoring for conveyor belts used in the mining industry. Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.