Patent Publication Number: US-9423305-B2

Title: Device for testing a sensor of train undercarriage temperatures

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a divisional application under 35 USC §121 claiming priority to U.S. patent application Ser. No. 13/605,764 filed on Sep. 6, 2012, which is based upon and claims the benefit of priority from European Patent Application No. EP11185451.9 by Alessandro Agostini et al., filed Oct. 17, 2011. 
    
    
     TECHNICAL FIELD 
     This disclosure generally relates to the field of rail transportation, and to the field of infrared sensors for undercarriage components of trains. This disclosure relates, more particularly, to the testing of infrared sensors for undercarriage components of trains. 
     BACKGROUND 
     Safe and reliable operation of a railroad system may be dependent upon the integrity of the undercarriage components of the vehicles travelling over the rails. Worn or damaged train wheel bearings may increase the rolling friction of an axle requiring an increase of power to move the train. In addition, worn or damaged bearings may cause excessive wear to the train axle and, in the case of failure of the bearing, may even cause the axle to lock up, preventing rotation of the wheel and thus resulting in a potential fire hazard due to the heat build up and potential sparking caused by friction of the locked wheel scraping along the rail. 
     Bearing temperatures may be scanned by sensing a temperature of the wheel bearing indirectly through a bearing box surrounding the wheel bearing on a rail car of a train. For example, infrared radiation (IR) sensors may be mounted along a rail to detect IR energy emitted by an outer wheel bearing of passing rail cars. The emissions of IR energy may be indicative of a temperature of the wheel bearing. 
     The bearing temperatures may be scanned by sensors that may comprise sensing elements which may be aimed at different parts of a target scanning area of a rail vehicle undercarriage component. The IR data obtained may be used to generate respective scanning signature waveform data corresponding to each different region. The sensor may be oriented such that at least one of the elements receives unobstructed infrared emissions from the undercarriage component of a rail vehicle passing the sensor. A control circuit for the sensors may cause an alarm to be raised if the IR data is indicative of temperature that is higher than a pre-set temperature threshold. 
     However, the sensors may have failures in performance which may not be detectable by the sensors or by the control circuit connected to the sensors. A failure may be the misalignment in a sensing element such that the element is no longer aimed at a target area of a rail vehicle undercarriage component. Another failure may be an incorrect data being generated based on the IR emissions. 
     The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of the prior art system. 
     BRIEF SUMMARY OF THE INVENTION 
     In a first aspect, the present disclosure describes a test apparatus for a IR sensor of a rail vehicle undercarriage component, the test apparatus comprising a heat emitter for producing IR emissions at a reference temperature; a support for supporting the heat emitter at a position spaced from the passage of the rail vehicle and in an orientation for directing the IR emissions at the IR sensor. 
     In a second aspect, the present disclosure describes a method of testing an IR sensor of a rail vehicle undercarriage component, the method comprising the steps of providing a heat emitter for producing IR emissions at a reference temperature; supporting the heat emitter on a support at a position spaced from the passage of the rail vehicle and in an orientation for directing the IR emissions at the IR sensor; activating the heat emitter to produce IR emissions at the reference temperature; and comparing the reference temperature and the temperature detected by the IR sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features and advantages of the present disclosure will be more fully understood from the following description of various embodiments, when read together with the accompanying drawings, in which: 
         FIG. 1  is a representation of a test apparatus positioned over a rail vehicle undercarriage and IR sensors embedded in a metal railroad tie, or sleeper according to the present disclosure; 
         FIG. 2  is a representation of a heat emitter according to the present disclosure; 
         FIG. 3  is an isometric representation of a test apparatus positioned over a rail vehicle undercarriage and IR sensors embedded in a metal railroad tie, or sleeper of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure generally relates to a test apparatus  10  for an infrared (IR) sensor which is provided to detect the temperatures of rail vehicle undercarriage components. 
     With reference to  FIG. 1 , the test apparatus  10  may test the accuracy and reliability of an IR sensor  36 . The test apparatus  10  may be located at a rail track  30  for testing the IR sensor  36  that may be positioned in a rail bed of the track  30 , such as within a cross tie or a sleeper  34 . 
     The IR sensor  36  may obtain IR data from a rail vehicle undercarriage  40 . The rail undercarriage  40  may comprise components such as wheels  44 , wheel bearings  46 ,  48  and an axle  42 . The IR sensor  36  may be orientated so as to obtain IR data from the one of the rail vehicle undercarriage components. The IR data may be obtained as the axle  42  passes over IR sensor  36 . 
     In an embodiment, a plurality of IR sensors  36  may be disposed in the rail bed of the track  30 . The IR sensors  36  may each be orientated to scan the various rail undercarriage components. 
     The test apparatus  10  may be positioned away from the passage of the rail vehicle. The passage of the rail vehicle may be defined as the spatial course of the rail vehicle travelling on the track  30 . The passage of the rail vehicle may also be defined as the movement of the rail vehicle travelling on the track  30 . 
     The test apparatus  10  may be positioned over the track  30 . In an embodiment, the test apparatus  10  may be positioned to the side of the track  30 . 
     The test apparatus  10  may comprise a heat emitter  14  and a support  18 . The heat emitter  14  may be connected to the support  18 . In an embodiment, the heat emitter may be coupled to a connecting member  16  for connection to the support  18 . 
     The heat emitter  14  may produce IR emissions. IR emissions may include both high speed thermal flashes and thermal radiation from a heated surface. The IR emissions may be at a reference temperature. The IR emissions may be controllably varied to be produced at different reference temperatures. The IR emissions may be detected by the IR sensor  36 . 
     With reference to  FIG. 2 , the heat emitter  14  may comprise at least one high speed infrared LED (IR LED)  24 . The IR LED  24  may generate high speed thermal flashes. The IR LED  24  may generate high speed thermal flashes. The IR LED  24  may be controlled by an electronic circuit external to the heat emitter  14 . In an embodiment, the IR LED  24  may be controlled by an electronic circuit within the heat emitter  14 . 
     In an embodiment, the heat emitter  14  may comprise a plurality of high speed IR LEDs  24 . The plurality of IR LEDs  24  may be arranged in an array that corresponds to an array of IR sensor elements in the IR sensor  36 . Each IR LED  24  may be controlled to generate high speed thermal flashes one at a time. The plurality of IR LEDs  24  may be controlled to generate high speed thermal flashes randomly. The plurality of IR LEDs  24  may be controlled to generate high speed thermal flashes randomly. 
     The plurality of IR LEDs  24  may be controlled to mimic a temperature pattern of a rail undercarriage component of a passing rail vehicle. The plurality of IR LEDs  24  may be controlled by an electronic circuit external to the heat emitter  14 . In an embodiment, the plurality of IR LEDs  24  may be controlled by an electronic circuit within the heat emitter  14 . 
     The heat emitter  14  may comprise a heat member  25  which is capable of producing thermal radiation. In an embodiment, the heat member  25  may comprise a black surface  26  coupled to a resistor. The resistor may heat the black surface  26 . In an embodiment, the black surface  26  may be superposed on the resistor. The resistor may be disposed in the heat emitter  14  so as not to interfere with the thermal radiation from the black surface  26 . The temperature of the black surface  24  may be regulated by varying the resistor. 
     The heat member  25  may be controlled by an electronic circuit external to the heat emitter  14 . In an embodiment, the heat member  25  may be controlled by an electronic circuit within the heat emitter  14 . 
     The heat emitter  14  may comprise a temperature sensor  28 . The temperature sensor  28  may sense the temperature of the black surface  26 . The temperature sensor  28  may allow the temperature of the black surface  26  to be controlled. The temperature sensor  28  may be disposed in the heat emitter  14  so as not to interfere with the thermal radiation from the black surface  26 . 
     The heat emitter  14  may comprise both the heat member  25  and the IR LED  24 . The heat member  25  and the IR LED  24  may be provided on the heat emitter  14  such that the IR emissions from either sources are detectable by the IR sensor  36 . The heat member  25  and the IR LED  24  may be disposed on a flat surface of the heat emitter  14 . The heat member  25  may be positioned adjacent to the IR LED  24 . 
     In an embodiment, the heat emitter  14  may comprise either the heat member  25  or the IR LED  24 . The heat member  25  or the IR LED  24  may be disposed on the heat emitter  14  such that the IR emissions may be detectable by the IR sensor  36 . 
     In an embodiment, the support  18  may be positioned to the side of the track  30 . The support  18  may comprise of upright beam  19 . The beam  19  may extend perpendicularly relative to the track  30 . The beam  19  may have a cross beam  17  cantilevered to the beam  19 . The cross beam  17  may be positioned at a height that is greater than the highest part of the rail vehicle. The beam  19  may be positioned away from the track  30 . 
     With reference to  FIG. 1 , in an embodiment, the support  18  may be positioned over the track  30 . The support  18  may be an upright frame spanning the track  30 . The support  18  may comprise of pair of upright beams  19  disposed on either sides of the track  30 . The beams  19  may extend perpendicularly relative to the track  30 . The beams  19  may be connected by a cross beam  17 . The cross beam  17  may be positioned over the track  30  and orthogonal to the rails  32  of the track  30 . The cross beam  17  may be positioned at a height that is greater than the highest part of the rail vehicle. The beams  19  may be positioned away from the track  30 . The position of the support  18  may correspond with the rail bed of the track  30  wherein IR sensor  36  or IR sensors  36  are located. 
     The support  18  may support the heat emitter  14  at a position suitable for testing the IR sensor  36 . The support  18  may support the heat emitter  14  at a position that is spaced from the passage of the rail vehicle. The heat emitter  14  may be in a position located away from the passage of the rail vehicle while suitable for testing the IR sensor  36 . The heat emitter  14  may be positioned over the track  30 . The heat emitter  14  may be positioned to the side of the track  30  and supported above the level of the track  30 . 
     The support  18  may support the heat emitter  14  in an orientation suitable for testing the IR sensor  36 . The heat emitter  14  may be installed on the support  18  such that the IR emissions may be detected by the IR sensor  36 . The support  18  may support the heat emitter  14  in an orientation for directing the IR emissions at the IR sensor  36 . The emission line  12  may indicate the direction of the IR emissions from the heat emitter  14 . 
     The heat emitter  14  may be installed on the support  18  to receive a scanning beam from the IR sensor  36  which is orientated to obtain IR emission data from the one of the rail vehicle undercarriage components. 
     The direction of IR emissions of the heat member  25  and the IR LED  24  on the heat emitter  14  may be indicated by the line  12 . The direction of IR emissions of the heat member  25  and the IR LED  24  may be detected by the IR sensor  36 . 
     In an embodiment, the direction of IR emissions of either the heat member  25  or the IR LED  24  on the heat emitter  14  may be indicated by the line  12 . The direction of IR emissions of the heat member  25  or the IR LED  24  may be detected by the IR sensor  36 . 
     In an embodiment, the test apparatus  10  may comprise a plurality of heat emitters  14 . The number of heat emitters  14  may correspond to the number of IR sensors  36  that are installed in the rail bed of the track  30 . 
     The support  18  may support the heat emitters  14  at specific positions that are suitable for testing respective IR sensor  36 . The support  18  may support the heat emitters  14  at positions that are spaced from the passage of the rail vehicle. The heat emitters  14  may be in positions located away from the passage of the rail vehicle while suitable for testing the respective IR sensors  36 . The heat emitters  14  may be positioned over the track  30 . 
     The support  18  may support the heat emitters  14  in specific orientations for directing the IR emissions at the respective IR sensors  36 . The emission lines  12  may indicate the directions of the IR emissions from each heat emitter  14  to the respective IR sensor  36 . 
     The plurality of heat emitters  14  may be installed on the support  18  at the respective positions so as to receive scanning beams from the corresponding IR sensors  36  that are orientated to obtain IR emission data from the respective rail vehicle undercarriage components. 
     The direction of IR emissions of the heat members  25  and the IR LEDs  24  on each heat emitter  14  may be indicated by the lines  12 . The direction of IR emissions of the heat members  25  and the IR LEDs  24  on each heat emitter  14  may be detected by the respective IR sensor  36 . 
     In an embodiment, the direction of IR emissions of the either the heat members  25  or the IR LEDs  24  on each heat emitter  14  may be indicated by the lines  12 . The direction of IR emissions of the heat members  25  or the IR LEDs  24  on each heat emitter  14  may be detected by the respective IR sensor  36 . 
     The test apparatus  10  may comprise a test circuit  20 . The test circuit  20  may connect the heat emitter  14  to a controller  22 . In an embodiment, the test circuit  20  may connect the plurality of heat emitters  14  to a controller  22 . The external electronic circuit controlling the IR LEDs  24  or the heat members  25  may be the test circuit  20  connected to the controller  22 . 
     With reference to  FIG. 3 , the test apparatus  10  may comprise a wheel sensor  50  that is connected to the controller  22 . In an embodiment, the test apparatus  10  may comprise a plurality of wheel sensors  50  that are each connected to the controller  22 . The controller  22  may be connected to the wheel sensors  50  and the IR sensors  36 . 
     The controller  22  may be connected to a sensor controller  23 . The sensor controller  23  may control the IR sensors  36 . The sensor controller  23  may activate the IR sensors  36  to detect for IR emissions. The sensor controller  23  may generate IR data based on the detected IR emissions. 
     A method of testing an IR sensor  36  of a rail vehicle undercarriage component may comprise the following steps. A heat emitter  14  may be provided for producing IR emissions at a reference temperature. The heat emitter  14  may be supported on a support  18  at a position spaced from the passage of the rail vehicle. The heat emitter  14  may be supported on a support  18  in an orientation for directing the IR emissions at the IR sensor  36 . The heat emitter  14  may be activated to produce IR emissions at the reference temperature. The reference temperature of the IR emissions and the temperature detected by the IR sensor  36  may be compared. 
     With respect to the heat emitter  14  comprising a high speed IR LED  24 , the step of activating the heat emitter  14  may comprise generating a high speed thermal flash from the high speed IR LED  24 . 
     With respect to the heat emitter  14  comprising a plurality of high speed IR LEDs  24 , the step of activating the heat emitter  14  may comprise generating high speed thermal flashes from the plurality of high speed IR LEDs  24 . The plurality of IR LEDs  24  may generate flashes which simulate the passage of a rail vehicle. This test may enable verification of the correct positioning of the scanning window. The scanning window may correspond to the target scanning area of a rail vehicle undercarriage component 
     The controller  22  may generate signals that simulate the wheel signals of a passing rail vehicle travelling at a known speed. The simulated wheel signals may simultaneously trigger the test apparatus  10  and the IR sensors  36 . 
     The simulated wheel signals may be transmitted to the IR LEDs  24  to generate thermal flashes. The thermal flashes may be at a pre-selected reference temperature. The IR LEDs  24  may generate thermal flashes sequentially. The simulated wheel signals may be transmitted to the sensor controller  23  for activation of the IR sensors  36  to detect the IR emissions corresponding to the thermal flashes. The IR emissions may be indicative of the temperature of the thermal flashes from the array of IR sensors  36 . 
     The controller  22  may compare the reference temperature of the thermal flashes generated by the IR LEDs  24  and the temperature which is obtained from the IR emissions detected by the IR sensor  36 . A mismatch in the reference temperature and the detected temperature may send an error signal. The controller  22  may check if an alarm has been raised if the reference temperature is greater than a pre-set threshold temperature. An error signal may be sent if an alarm is not raised when the reference temperature is greater than a pre-set threshold temperature. 
     The foregoing steps may enable the IR sensors  36  to be tested for the following functions: measurement of synchronicity with the IR LEDs  24 , velocity calculation of the rail vehicle and the reduction factor of the acquired IR emissions data. 
     With respect to the heat emitter  14  comprising the heat member  25  having a black surface  26  coupled to a resistor, the step of activating the heat emitter  14  may comprise heating the black surface  26  by the resistor. The controller  22  may transmit signals to the resistor so as to heat the black surface  26  to a pre-selected temperature. The temperature of the black surface  26  may be checked by the controller  22  through the temperature sensor  28 . 
     The controller  22  may transmit signals to the sensor controller  23  for activation of the IR sensors  36  to detect the IR emissions corresponding to the thermal radiation from the black surface  26  when the temperature of the black surface  24  reaches a pre-selected temperature. The IR emissions may be indicative of the temperature of the thermal radiation from the black surface  24 . 
     The controller  22  may compare the reference temperature of the thermal radiation from the black surface  26  and the temperature which is obtained from the IR emissions detected by the IR sensor  36 . A mismatch in the reference temperature and the detected temperature may send an error signal. The controller  22  may check if an alarm has been raised if the reference temperature is greater than a pre-set threshold temperature. An error signal may be sent if an alarm is not raised when the reference temperature is greater than a pre-set threshold temperature. 
     The foregoing steps may enable the IR sensors  36  to be tested for the following functions: IR sensor  36  alignment to the heat emitter  14  and the accuracy of the measurement by the IR sensor  36 . 
     The heat member  25  may enable the measurement accuracy of the IR sensor  36  to be tested to a high level of accuracy since the reference temperature may be accurately controlled by the resistor and may be checked by the temperature sensor  28 . The reference temperature may be varied to specific pre-selected values through the controller  22 . 
     The test apparatus  10  may be provided with a plurality of heat emitters  14  corresponding to a plurality of IR sensors  36 . Each heat emitter  14  may supply a reference temperature for detection by a corresponding IR sensor  36 . 
     The step of activating the heat emitter  14  may comprise activating the plurality of heat emitters  14  one at a time. The plurality of heat emitters  14  may be activated in sequence. The plurality of heat emitters  14  may be activated randomly. The controller  22  may transmit signals resistor so as to heat the respective black surfaces  26  to a pre-selected temperature. 
     The controller  22  may transmit signals to the sensor controller  23  for activation of the IR sensor  36  corresponding to the activated heat emitter  14  when the temperature of the black surfaces  26  reaches the pre-selected temperature. The IR sensors  36  may be activated to detect the IR emissions corresponding to the thermal radiation from the respective black surfaces  26 . 
     The controller  22  may compare the reference temperature of the thermal radiation from the black surfaces  26  and the temperature which is obtained from the IR emissions detected by the IR sensors  36 . A mismatch in any one of the reference temperatures and the detected temperatures may send an error signal. The controller  22  may check if an alarm has been raised if the reference temperatures are greater than a pre-set threshold temperature. An error signal may be sent if an alarm is not raised when the reference temperatures are greater than a pre-set threshold temperature. 
     In an embodiment, the plurality of heat emitters  14  may be activated simultaneously. The controller  22  may transmit signals resistor so as to heat the respective black surfaces  26  to a pre-selected temperature. The controller  22  may transmit signals to the control circuit of the IR sensors  36  corresponding to the activated heat emitter  14  when the temperature of the black surfaces  26  reaches the pre-selected temperature. The IR sensors  36  may be activated alternatively to detect the IR emissions corresponding to the thermal radiation from the respective black surfaces  26 . The plurality of IR sensors  36  may be activated in sequence. The plurality of IR sensors  36  may be activated randomly. 
     The step of activating the heat emitter  14  may comprise activation of a wheel sensor  50 . The controller  22  may monitor the wheel sensor  50  and record the signals and the information relating to the passage of a rail vehicle used by the IR sensors  36  to detect the IR emissions from an undercarriage component. After a time lag the controller may activate the heat emitter  14  and may transmit signals to the IR sensor  36 . The controller  22  may use the signals and information from the wheel sensor  50  to issue signals which replicate signals from the wheel sensor  50 . The replicated signals from the controller may simulate the wheel signals of a passing rail vehicle travelling at a known speed. The replicated wheel signals may simultaneously trigger the test apparatus  10  and the IR sensors  36 . 
     The replicated wheel signals may be transmitted to the IR LEDs  24  to generate thermal flashes. The thermal flashes may be at a pre-selected reference temperature. The IR LEDs  24  may generate thermal flashes sequentially. The replicated wheel signals may be transmitted to the sensor controller  23  for activation of the IR sensors  36  to detect the IR emissions corresponding to the thermal flashes. The IR emissions may be indicative of the temperature of the thermal flashes from the array of IR sensors  36 . 
     The controller  22  may compare the reference temperature of the thermal flashes generated by the IR LEDs  24  and the temperature which is obtained from the IR emissions detected by the IR sensor  36 . A mismatch in the reference temperature and the detected temperature may send an error signal. The controller  22  may check if an alarm has been raised if the reference temperature is greater than a pre-set threshold temperature. An error signal may be sent if an alarm is not raised when the reference temperature is greater than a pre-set threshold temperature. 
     The above tests may be performed by the controller  22  periodically at pre-determined time intervals. 
     The skilled person would appreciate that foregoing embodiments may be modified or combined to obtain the test apparatus  10  of the present disclosure. 
     INDUSTRIAL APPLICABILITY 
     This disclosure describes a test apparatus  10  for testing an IR sensor  36  which may be used to obtain data, such as infrared IR emission data. The data may be obtained by sensing a wheel  44  or a wheel bearing  46 ,  48  of a vehicle, such as a rail car, passing over the IR sensor  36 . 
     The test apparatus  10  may perform a test on the IR sensor  36  in the absence of a passing rail vehicle or immediately upon passage of a rail vehicle. The test apparatus  10  may test the accuracy of the infrared IR emission data obtained by the IR sensor  36 . The test apparatus  10  may test the alignment of the IR sensor  36 . The test apparatus  10  may test the correct position of a measuring window of the IR sensor  36 . 
     Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein. 
     Where technical features mentioned in any claim are followed by references signs, the reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, neither the reference signs nor their absence have any limiting effect on the technical features as described above or on the scope of any claim elements. 
     One skilled in the art will realise the disclosure may be embodied in other specific forms without departing from the disclosure or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting of the disclosure described herein. Scope of the invention is thus indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.