Patent Publication Number: US-11657660-B2

Title: System for diagnosing errors and defects of components of a machine and detecting and diagnosing environmental conditions in a hazardous workspace surrounding the machine

Description:
RELATED APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 15/084,801 filed on Mar. 30, 2016, which issued as U.S. Pat. No. 10,127,739 on Nov. 13, 2018; which was a continuation-in-part of PCT/US2014/048118 filed on Jul. 25, 2014, which was the international application of U.S. patent application Ser. No. 14/212,668 filed Mar. 14, 2014, which issued as U.S. Pat. No. 9,041,546 on May 26, 2015; which was the non-provisional application of U.S. Provisional Patent Application Ser. No. 61/792,530 filed Mar. 15, 2013. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a system and method for the detection of one or more locator units in the proximity of a transmitter system. More specifically, the present invention relates to a system that detects the proximity of a person or machine carrying the locator to a dangerous machine configured with the driver system, and determines the exact location of that person or machine and if that person or machine is close enough to be in danger. The system and method according to the present invention can also be used in a vehicle to vehicle collision avoidance setting where one or more drivers are positioned on a primary vehicle and a locator is positioned on each of one or more secondary vehicles. The proximity detection system and method of the present invention can be used on any mobile equipment, and is not intended to be limited to the mining industry. 
     Description of Prior Art 
     Industrial machines may be necessarily large and powerful. For example, continuous mining machines may be 40 feet long, 10-12 feet wide, 3-4 feet tall, and weigh 40 tons. Such machines have injured or killed people while being operated. For example, in “tramming,” a continuous mining machine mounted on tracks is moved from one location to another in confined spaces at relatively high speeds and can turn or change directions fast enough to pin an operator against a rib (i.e., wall) of the mining space. 
     With respect to the environment, it may not be possible to set up traditional operator protection systems, such as light fences or guard rails, because the environment is generally unstructured (e.g., mining machines create the environment as they operate). Further, such environments are often noisy, dusty and wet. 
     A transducer, speaker or microphone that is exposed to such an environment is not likely to survive or function properly. For example, sonar and laser time-of-flight sensors exposed to such an environment will become dirty and non-operational very quickly. Further, such sensors have difficulty distinguishing between a person and other structural components in the environment, such as the wall of the mining space. 
     With respect to radio time-of-flight sensors, such as radar, while the components may be more durable in the environment the relatively short distances (e.g., two feet to 50 feet) between the operator and the machine make such sensors impractical and unreliable. Further, the requirement of a relatively large radio dish or directional radio antenna is impractical. 
     Alternatively, other systems utilize a magnetic field generator on the machine and a magnetic field sensor carried by the operator. The magnetic field generator creates a magnetic field around the machine. The magnetic field sensor senses the strength of the magnetic field and then relays the strength of the field by radio back to the machine. If the operator is determined to be too close to the machine, the machine is shut down. However, this system is limited to a substantially circular safety perimeter around the machine, so there is no ability to arbitrarily define a safety perimeter because there is no way to determine an exact location of the operator with respect to the machine. Thus, the safety perimeter must be set to a radius that includes a safety margin from the most distant points of concern of the machine, leaving areas that are safe inside of the safety perimeter. This becomes a nuisance because it prevents the operator from operating in areas that are safe and effective because of the lack of geometric control of the safety perimeter. 
     In the invention disclosed in U.S. Pat. No. 8,289,170, applicants herein invented a system that could determine the location of the operator with respect to the machine and, if necessary, shut the machine down without requiring any structure in the environment. That system included transmitters on the operators and a plurality of receiver units on the machine. One disadvantage of this system is that, because the transmitters are on the operators, not the machine, power and range are necessarily limited. 
     Thus, what is needed is a system for determining the location of the operator with respect to the machine wherein an encoded signal of greater power can be transmitted to increase the area in which an operator can be detected. Further, there is needed a system where the range and shape of the encoded signal can be customized and modified to suit the particular needs of the machinery being used. Advantageously, with such a system, the operator will learn to maintain a safe distance from the machine to be efficient in their job. 
     SUMMARY OF THE INVENTION 
     The present invention is a system for detecting the angle of articulation at an articulating point between a first section and a second section of an articulating machine. According to one aspect of the system of the present invention includes a controller positioned on the articulating machine for generating a uniquely encoded signal. A plurality of drivers is positioned on the second section of the articulating machine such that they are in communication with the controller for transmitting the uniquely encoded signal. A machine mounted locator is positioned on the first section of the articulating machine such that it is in communication with the drivers. The uniquely encoded signal is a magnetic signal according to one aspect of the present invention. 
     Means for determining the angle of articulation between the first section and second section of the articulating machine at the articulating point are also provided according to this aspect of the invention. According to a further aspect of the invention, the means for determining the angle of articulation includes an algorithm performed at the controller based on the uniquely encoded signal and a radio frequency signal generated by the machine mounted locator. 
     The system may further include one or more drivers positioned on the first section of the articulating machine. Those drivers are in communication with the controller for transmitting the uniquely encoded signal. 
     According to a further aspect of the invention, means for defining one or more safety zones around the articulating machine may be provided. The one or more safety zones may comprise a first warning boundary zone and a second operation limiting boundary zone. Means for dynamically altering the one or more safety zones are provided according to another aspect of the invention. The one or more safety zones may be dynamically altered depending upon the detected articulation angle. 
     According to yet a further aspect of the invention, a digital radio transceiver may be located in the controller, which also generates a driver radio frequency signal. The digital radio transceiver transmits the driver radio frequency signal. According to this aspect of the invention, the encoded signal is a uniquely encoded magnetic signal and the machine mounted locator comprises a locator microcontroller for processing data and controlling locator functions, one or more magnetic proximity signal receiving coils in communication with the locator microprocessor for receiving the uniquely encoded magnetic signal, and a digital radio transceiver in communication with the locator microcontroller for receiving the driver magnetic frequency signal and transmitting a locator radio frequency signal. The one or more magnetic proximity receiving coils may include a first magnetic proximity signal receiving coil; a second magnetic proximity signal receiving coil oriented orthogonally to the first magnetic proximity signal receiving coil; and a third magnetic proximity signal receiving coil oriented orthogonally to the first magnetic proximity signal receiving coil and to the second magnetic proximity signal receiving coil. 
     Another aspect of the present invention is a system for diagnosing errors and defects of components of a machine and detecting and diagnosing environmental conditions in a hazardous workspace surrounding the machine. That diagnostic system includes a transmitter system and a machine mounted locator located on the machine, a locating means for determining the coordinates of the machine mounted locator relative to the transmitter system, and error detection means for determining whether the coordinates of the machine mounted locator relative to the transmitter system are within programmed parameters. A second machine mounted locator mounted on the machine may also be provided. The error detection means according to a further aspect of the invention may include means for differentiating machine errors from environmental errors. The transmitter system may include one or more drivers positioned on the machine, where the drivers are in communication with a controller for transmitting a uniquely encoded signal. The error detection means according to one aspect of the invention includes an algorithm performed at the controller based on the uniquely encoded signal and a radio frequency signal generated by the machine mounted locator. The system for diagnosing errors may further include means for defining one or more safety zones around the machine, which may by dynamically altered depending upon the detected environmental conditions. 
     These and other features, aspect and advantages of the present invention will become clearer by reviewing the drawings and detailed description herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a functional block diagram of an exemplary system for proximity detection according to the invention. 
         FIG.  2    is a schematic diagram of the exemplary system of claim  1 . 
         FIG.  3    is plan view showing exemplary boundaries around a machine operated with the exemplary system of  FIG.  1   . 
         FIG.  4    is a functional block diagram of an exemplary locator of the exemplary system of  FIG.  1   . 
         FIG.  5    is a functional block diagram of an exemplary driver of the exemplary system of  FIG.  1   . 
         FIG.  6    is a functional block diagram of an exemplary controller of the exemplary system of  FIG.  1   . 
         FIG.  7    is a schematic diagram of an operator in proximity to a machine whose location is determined using two of a plurality of the drivers. 
         FIG.  8    is a schematic diagram of an exemplary locator positioned in an exemplary charger unit. 
         FIG.  9    is a top plan view showing an alternative embodiment of the system for proximity detection in use on an articulating machine. 
         FIG.  10    is a top plan view of the system for proximity detection shown in  FIG.  9    depicting the methodology for determining the position of the machine mounted locator. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     For the purpose of this document, “intrinsically safe” shall be as defined by the U.S. Department of Labor, Mine Safety and Health Administration (MSHA). Further, for the purpose of this document, the various microcontrollers described herein are understood to execute software or program instructions included in or accessible by the microcontrollers in a tangible storage medium, such as random access memory (RAM), read only memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), flash memory, or the equivalent. 
       FIG.  1    and  FIG.  2    show an exemplary system  10  for detecting the proximity of a person  22  to a machine  11 , including: at least a first locator  12   a , a plurality of drivers  14   a - 14   d , a controller  16 , and a warning indicator or device  18 . The drivers  14   a - 14   d  emit a magnetic field around the machine  11 , and the locators  12   a - 12   c  respond to this magnetic field and communicate via radio frequency (RF) with the controller  16 . The controller  16  performs an algorithm to determine where, in relation to the machine  11 , the locators  12   a - 12   c  are positioned. When a locator, for example the first locator  12   a , breaches one of the configurable zones  24 ,  26  created around the machine, the proper configuration action is performed. 
     The plurality of drivers  14   a - 14   d  and the controller  16  comprise a transmitter system. The proximity system controller  16  generates and transmits, through the plurality of drivers  14   a - 14   d , a uniquely encoded magnetic signal, simultaneously or sequentially from each driver. The signal may be equal for all drivers or also may be unique to each driver. The controller  16  also generates and transmits a driver RF packet prior to the transmission of driver magnetic signals. The driver RF packet is transmitted from a digital radio transceiver located in the system controller  16 . The driver RF packet contains parameters including: magnetic signal timing, signal duration, frequency construction, encoding, signal type, message time &amp; date stamp, and machine serial number. This information allows the locator  12  to be synchronized with the driver  14  and search for and retrieve the signal in the presence of radio and magnetic noise. 
     The machine  11  also includes a control interface  20  for receiving commands to control operation of the machine  11  and for reporting an operating state of the machine  11 . 
     The system utilizes a plurality of locators  12   a - 12   c  for being carried by a person  22  in proximity to the machine  11 . Each locator, such as first locator  12   a , receives the uniquely encoded magnetic proximity signal generated by the drivers  14   a - 14   d  and also receives the RF packet containing information from the machine driver RF transmission. The locator  12   a  processes the data from the plurality of drivers  14   a - 14   d  and the RF packet and transmits a response RF packet to the machine controller  16 . The locator RF packet contains processed values from the plurality of driver received signals, driver RF packet, and processed locator data such as translated distance values from locator to each respective driver, locator serial number, message time &amp; date stamp, locator battery status, and locator operational status. 
     The machine controller  16  is in communication with the plurality of driver units  14   a - 14   d  and includes or accesses data defining a first boundary around the machine  11 . The processing unit  16  determines a location of the first locator unit  12   a  relative to the machine  11  based on the received signal strength of the magnetic proximity signal received by the locator from at least two of the plurality of driver units  14   a - 14   d  and the known location of the at least two of the plurality of driver units  14   a - 14   d . The processing unit  16  then determines if the location of the first locator unit  12   a  relative to the machine  11  is within the first boundary around the machine  11  and outputs a proximity warning signal if the first locator unit  12   a  is within the first boundary around the machine  11 . 
     The machine  11  includes a control interface  20  for controlling operation of the machine  11  and for reporting an operating state or operating status of the machine  11 , and the controller  16  is in communication with the control interface  20 . The machine  11  may be, for example, a continuous mining machine or another type of underground mining machine. 
     The warning device  18  is in communication with the processing unit  16  and provides at least a visual signal in response to receiving the proximity warning signal from the processing unit  16 . The warning device  18  may also provides an audible signal in response to receiving the proximity warning signal from the processing unit  16 . Thus, the warning device  18  may be, for example, a flashing strobe light and horn. Alternatively, the visual portion of the warning device may be incorporated into the status indicator  68  of each of the drivers  14   a - 14   d.    
       FIG.  3    shows the machine  11  according to one presently preferred embodiment, including the plurality of drivers  14   a - 14   d  and a first boundary  24  around the machine  11 . Advantageously, the first boundary  24  around the machine  11  can be defined to have any geometric shape. Also shown is a second boundary  26  around the machine  11 . The second boundary  26  around the machine  11  is also defined by data included in or accessible by the controller  16 . Thus, for example, the first boundary  24  may be considered a “warning boundary” and the second boundary  26  may considered a “operation limiting” boundary. Additional boundaries may also be defined by data accessible by the controller  16 . 
     When the controller  16  determines the location of the first locator  12   a  or any other locator (e.g., second locator  12   b , third locator  12   c ) (generally referred hereinafter as “locator  12 ”), the controller  16  will respond based on the determined location. Thus, for example, if the locator  12  is at a location  28   a , which is outside of the first boundary  24  around the machine  11 , no action would be taken. However, if the locator  12  is determined to be at a location  28   b  that is within the first boundary  24  around the machine  11 , the warning device  18  ( FIG.  1    and  FIG.  2   ) will provide at least a visual signal indicating that the location of the locator  12  relative to the machine  11  is within the first boundary  24 . Further, the controller  16  ( FIG.  1    and  FIG.  2   ) outputs a control signal to the control interface  20  ( FIG.  1    and  FIG.  2   ) to limit the operation of the machine  11  if the location of the locator is at a location  28   c  relative to the machine  11  is within the second boundary  26  around the machine  11 . 
     As mentioned, the controller  16  may include data defining a plurality of boundaries around the machine  11 . Then, the controller  16  may receive an operating state signal indicating the operating state of the machine  11  from the control interface  20  of the machine, select a boundary (i.e., a “selected boundary”) from the plurality of boundaries around the machine  11  based on the operating state signal (i.e., different boundaries can be selected based on different operating states of the machine (e.g., mining, moving or“tramming,” etc.)), and output a control signal to the control interface  20  to limit the operation of the machine  11  if the location of the locator  12  relative to the machine  11  is within the selected boundary. 
       FIG.  4    shows an exemplary locator  12 , which is for being carried by a person. Although the drawings show only a single locator  12   a , or three locators  12   a ,  12   b ,  12   c , it is anticipated and understood that any number of locators  12  can be used. The locator unit  12  comprises a locator microcontroller  36  for processing data and controlling locator functions, and a first magnetic proximity signal receiving coil  30  for receiving the magnetic proximity signal. The first locator unit may further comprise: a second magnetic proximity signal receiving coil  32  in communication with the locator microcontroller  36  and oriented orthogonally to the first magnetic proximity signal receiving coil  30 ; a third magnetic proximity signal receiving coil  34  in communication with the locator microcontroller  36  and oriented orthogonally to the first magnetic proximity signal receiving coil  30  and to the second magnetic proximity signal receiving coil  32 ; and an accelerometer  48  in communication with the locator, the accelerometer measuring a direction of gravity. 
     The locator microcontroller  36  receives from all coils  30 ,  32 ,  34  the magnetic proximity signal and then may process the signals in any combination, mathematically processed or raw, from individual or multiple coils. The locator  12  may also select a most appropriate single coil signal based on the direction of gravity. The output from the coil or coils then passes through an analog to digital converter  38  before being received by the microcontroller  36  and/or transceiver  50 . 
     The locator also contains a digital radio transceiver  50  receiving and transmitting RF packets by way of antenna  52 . The locator microprocessor  36  receives the driver RF packet containing synchronization, frequency construction, encoding, and signal type information. This information allows the locator  12  to be synchronized with the driver  14  and search for and retrieve the magnetic signal in the presence of radio and magnetic noise. 
     The locator microcontroller  36  processes the data from the plurality of drivers  14   a - 14   d  and the driver RF packet and transmits a locator RF packet to the machine controller  16 . The locator RF packet contains processed values from the plurality of driver received signals, driver RF packet, and processed locator data such as translated distance values from locator to each respective driver, locator serial number, message time &amp; date stamp, locator battery status, and locator operational status. 
     The exemplary locator  12  is preferably contained in a dust proof enclosure that passes both the magnetic proximity signal and a digital radio transmission. The enclosure may be mechanically keyed to match a locator charging station (not shown), and includes external contacts  40  for making electrical contact with the transmitter charging station. When the locator  12  is inserted into the charging station, the external contacts  40  provide a safe means of charging an internal battery  42  and digitally communicating with the locator microcontroller  36 . The digital communications may be used to perform functional integrity test on the locator and locator battery to ensure proper locator operation prior to field use. Also, preferably, the locator  12  is intrinsically safe. 
     Charging current is controlled by a battery manager and local regulator circuit  44 . The internal battery  42  is connected to the battery manager and local regulator circuit  44  through a battery protection circuit  46 . The battery protection circuit  46  protects the battery from overcharge, over discharge, and over current conditions. The battery manager and local regulator circuit  44  feeds power to the transmitter microcontroller  36  and the coil driver circuit  38 . It is noted that the functionality of the battery manager and local regulator circuit  44  can be accomplished by other circuit configurations without departing from the spirit or the scope of the invention as claimed hereinafter. 
     The exemplary locator  12  also includes means for accepting input from and displaying information to the person  22 . Specifically, an input button  39  which is in communication with the microcontroller  38  may be provided to accept input from the person  22 . Status lights  41 , an audible indicator  43  and/or a display screen  45  may also be provided in communication with the microcontroller  38  to provide information to the person  22 . The display screen  45  may further comprise a touch-screen type device that is capable of both displaying information to the person  22  and accepting input from the person  22 . 
       FIG.  5    shows an exemplary driver  14  including a power and signal conditioner  60 , microcontroller  62 , coil driver  64 , coil  66  and status indicators  68 . A magnetic proximity signal is generated by the controller  16  and passed on to the driver(s)  14 . The magnetic proximity signal is passes through a power and signal conditioner  60  to prepare it for transmission. The signal is then transmitted to the driver microprocessor  62  for further enhancement of modification. Alternatively, if no further enhancement or modification is required, the signal can be passed directly to the coil driver  64 . Both the signal conditioner  60  and microcontroller  62  are in communication with the magnetic proximity transmitting coil  66  through the coil driver  64 . Lighted status indicators  68  are in communication with the driver microcontroller  62 , and are externally visible to indicate to the operator that a magnetic proximity signal is being transmitted by the driver  14 . 
     The exemplary driver  14  is contained in an enclosure that is strong enough to be machine mounted and survive in a mining environment, but still pass the magnetic proximity signal. Preferably, the enclosure (not shown) has at least one window to allow status lights to be visible externally. 
       FIG.  6    shows an exemplary controller  16  including a processing unit microcontroller  100  and a non-volatile storage medium  102 . The controller microcontroller  100  is in communication with a plurality of driver connectors  104   a - 104   d  through a plurality of communication interfaces  106   a - 106   d . Each of the plurality of driver connectors  104   a - 104   d  is in communication with a respective one of the drivers  14   a - 14   d  ( FIG.  1    and  FIG.  2   ). 
     The exemplary controller  16  receives power from the machine via a power input  108 . A receiver power controller  110  is in communication with the power input  108  and preferably provides intrinsically safe power to the plurality of drivers  14   a - 14   d  ( FIG.  1    and  FIG.  2   ) via the plurality of driver connectors  104   a - 104   d . The plurality of communication interfaces  106   a - 106   d  also preferably makes communication between the controller microcontroller  100  and the plurality of drivers  14   a - 14   d  ( FIG.  1    and  FIG.  2   ) intrinsically safe. However, it is noted that the principals taught herein are not limited to configurations requiring intrinsically safe power, but apply generally to equivalent non-intrinsically safe configurations. Preferably, the exemplary controller  16  is housed in an explosion proof enclosure. 
     Also shown are machine inputs  113 , machine input connectors  114 , machine outputs  116  and machine output connectors  118 , which cooperate with the control interface  20  of the machine  11  ( FIG.  1    and  FIG.  2   ) for receiving the operating state signal indicating the operating state of the machine  11  and outputting a control signal to the control interface  20  of the machine  11 . Additional input/output to the controller microcontroller  100  are provided by USB  124 , CANbus  125  and Ethernet  126  connectors. 
     Still further, the controller microcontroller  100  is in communication with a warning indicator connector  120  for outputting the proximity warning signal. A power regulator  122  is in communication with the power input  108  and provides power to the exemplary controller  16 . 
     The controller  16  further includes a digital radio transceiver  121  and digital radio antenna  123 . One or more antennas  123  may be used as needed. The antenna  123  is shown in  FIG.  6    as being internal to the housing of the controller  16 . Alternatively, the system may utilize one or more antennas that can be mounted externally to the controller  16 . The transceiver  121  is in communication with the microcontroller  100  for receiving and processing the RF packet from the locator(s)  12 , which contains processed values from one or more of the plurality of driver received signals, driver RF packet, and processed locator data such as translated distance values from locator to each respective driver, locator serial number, message time &amp; date stamp, locator battery status, and locator operational status. 
     The controller  16  further may use the microcontroller  100  to process data packets for use by remote monitoring and control systems. These packets may be transmitted via the digital radio transceiver  121  and digital radio antenna  123  for receipt by external systems. Further, the controller  16  may use the microcontroller  100  to process data packets transmitted from a remote system and received via the digital radio transceiver  121  and digital radio antenna  123 . 
     For example, in one exemplary methodology for determining the position of the locator(s), as shown in  FIG.  7   , for each RF transmission by the transceiver  50  of the locator(s)  12 , the controller  16  will receive a distance value from at least two of the plurality of drivers  14   a - 14   d . The controller  16  then selects the two drivers (e.g., two of drivers  14   a - 14   d ) with the lowest distance values, or drivers  14   c  and  14   d  in the example. Given the known locations of the drivers  14   c ,  14   d  mounted on the machine  11 , an arc of distance  130 ,  132  from each driver  14   c ,  14   d  is determined. The two arcs  130 ,  132  will intersect in two places. The location that is to the exterior of the machine  11  is the correct location. The second location  134  is dismissed since it is not to the exterior of the machine  11  with reference to the drivers  14   c ,  14   d , and because the second location  134  would also be closer to the other drivers  14   a ,  14   b  if this was the real location. 
     One of skill in the art will recognize that other equivalent methodologies for determining the position(s) of the locator(s) are possible within the spirit and scope of the invention as claimed hereinafter. Such methodologies may utilize more than two drivers to perform the locating function and calculation. Similarly, in some configurations, only a single driver may be used to perform the locating function and calculation. 
       FIG.  8    shows an exemplary locator  12  positioned in an exemplary charger unit  140 . The external context  40  of the exemplary locator  12  are biased against a set of charging contacts  142  of the charger  140 , which are supplied with power from a power supply  144 . Additionally, although not shown, a communication with the locator microcontroller  36  may also be made through the external context  40  of the locator  12  and the charger context  142  of the charger  140 . 
       FIG.  9    shows an alternative embodiment of the system for proximity detection in use on an articulating machine having a front section  11   a  and a rear section  11   b  connected at an articulation point  111 . As in the embodiment shown in  FIGS.  1 - 8   , a plurality of drivers  14   a - 14   d  are positioned on the machine. According to the particular embodiment shown in  FIG.  9   , first and second drivers  14   b ,  14   c  are located on the front section  11   a  of the machine, and third and fourth drivers  14   a ,  14   d  are located on the rear section  11   b  of the machine. The remaining components (e.g. controller  16 , warning indicator  18 , and control interface  20 ) of the system for proximity detection according to this embodiment are the same as in the embodiment shown in  FIGS.  1 - 8   , and are not shown here for convenience. 
     The addition of a machine mounted locator  112  at a known fixed position on the rear section  11   b  of the machine allows for the calculation of the angle at the articulation point  111  when the machine articulates. With this data, an algorithm that has been updated to utilize the position of the machine mounted locator  112  can be used to determine the location of an external locator  12   a . Specifically, the new position of the drivers  14   a ,  14   d  associated with the rear section  11   b  of the machine is used, within the current tracking algorithm, to calculate the position of locator  12   a , relative to the machine. This configuration is specifically for articulating machinery and not all equipment will need the machine mounted locator  112 . Although the machine mounted locator  112  is shown in  FIG.  9    as being positioned on the rear section  11   b  of the articulating machine, it could also be located on the front section  11   a  without departing from the scope of the present invention. 
     As best shown in  FIG.  10   , the methodology for determining the position of the machine mounted locator  112  is exactly the same as the methodology for determining the position of the mobile locator  12   a , as shown in  FIG.  7   . For each RF transmission by the transceiver  50  of the machine mounted locator  112 , the controller  16  will receive a distance value from the drivers  14   b ,  14   c  located on the front section  11   a  of the articulating machine  11 . Because the locations of the drivers  14   a ,  14   b  on the rear section  11   b  of the articulating machine  11  are fixed relative to the machine mounted locator  112  which is also mounted on the rear section  11   b , we are not concerned with the distances as they are fixed. Given the known locations of the drivers  14   b ,  14   c  mounted on the front section  11   a  of the articulating machine  11 , an arc of distance  230 ,  232  from each driver  14   b ,  14   c  is determined. The two arcs  230 ,  232  will intersect in two places. The location that is in the direction of the rear section  11   b  of the machine  11  is the correct location. The second location  134  is dismissed since it is not in the direction of the rear section  11   b  where the machine mounted locator  112  is known to be positioned. Using simple geometry, the angle of articulation θ can be calculated. 
     Once established, the zones, or boundaries  24 ,  26  ( FIG.  3   ) around the machine  11  may change dynamically based on machine  11  feedback to the controller  16 . The size and location of the zones may change based on the machine  11  moving or stationary, the speed of the machine, the articulation angle, etc. This is particularly important for the articulating machine embodiment shown in  FIG.  9   . 
     The machine mounted locator  112  may also be utilized as a diagnostic tool to detect and diagnose faults in the various components of the system, including, but not limited to magnetic and RF components. For instance, where the distance between driver units  14   a ,  14   d  on the rear section  11   b  of the articulating machine and the machine mounted locator  112  is fixed and known, anomalous readings that would indicate the driver unit  14   a ,  14   d  is closer or further than a specified, programmed buffer range would suggest that the driver unit, or the machine mounted locator is malfunctioning. Various algorithms can be programmed into the controller to assess what the malfunction is based on the data received. The machine mounted locator  112  may be used to provide diagnostic information for other components, including RF transmissions between components in the same manner. 
     The machine mounted locater  112  may also be used to diagnose certain environmental conditions, such as ferrous objects in the environment (i.e. hog panels and/or metal mesh on the ceiling to hold back loose earth), and take appropriate action to compensate for such conditions. This would also apply where absorbing and/or reflective material is present in the environment that would distort the magnetic and/or RF signals. To detect such environmental conditions, the machine mounted locator  112  would be programmed with a certain threshold with regard to the parameters of a magnetic signal and/or RF signal. If there is a change beyond the threshold, it may suggest a hazardous environmental condition that would require the warning zones to be adjusted to compensate for the condition. The magnitude of change is the difference between the environment and the machine. 
     To better distinguish environmental conditions from machine conditions, two machine mounted locators  112  could be mounted on the machine. If both machine mounted locators are detecting the same anomaly, it is likely an environmental condition, whereas an anomaly in only one machine mounted locator would strongly suggest a machine condition. This could also be applied to detect problems when inconsistent information is received from a remote locator. If two RF antennas are located on the controller, it would be expected that packets on both antennas would be received at the same rate, for example 10 times per second. If there is a significant difference between the rates for the two antennas, it may be due to environmental conditions such as one of the locators being occluded. 
     One of ordinary skill in the art will recognize that additional steps and configurations are possible without departing from the teachings of the invention. Although the preferred embodiments of the present invention describe and utilize magnetics data to calculate the location of the person or second machine, other similar distance measurement data from a variety of sensors may be used to obtain similar results. One such alternative to magnetics data would be to utilize radio waves to calculate the location of the person or second machine. Such radio wave technologies as RAdio Detection And Ranging (RADAR) or Radio Frequency IDentification (RFID) may be used within the spirit and scope of the present invention. Similarly, laser light based remote sensing technologies such as LIght Detection And Ranging (LIDAR) may also be used to as a substitute for magnetics data. Other equivalent technologies for remote sensing will be apparent to those of skill in the art. 
     This detailed description, and particularly the specific details of the exemplary embodiment disclosed, is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modifications will become evident to those skilled in the art upon reading this disclosure and may be made without departing from the spirit or scope of the claimed invention.