Abstract:
A system and method provide the capability to dynamically measure the diameter of a train wheel. An onboard sensor signals detection and loss of detection of a proximity plate having a predetermined length and placed along a direction of travel of the train. A signal generator generates a signal indicating the number of revolutions of the wheel. Based on the sensor signals indicating detection and loss of detection of the proximity plate, the length of the proximity plate, and the corresponding number of wheel revolutions, a controller automatically calculates the wheel diameter.

Description:
BACKGROUND 
       [0001]    For communication-based train control (CBTC) operation, accurate train position is required to facilitate both automatic and manual moving block operation. In addition, in order to stop a train accurately at stations, with or without platform doors, the precise position of the train is used. Positional precision is also beneficial when parking trains in close proximity in storage and pocket tracks. 
         [0002]    To determine position and distance traveled, wheel revolutions are monitored, with distance calculated based on a number of revolutions and wheel diameter. To obtain accurate distance calculations, accurate determination of train wheel diameter is therefore fundamental. It is also desirable to be able to make such determinations dynamically, so that train operation is not slowed or interrupted for wheel diameter measurements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    One or more embodiments are illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout and wherein: 
           [0004]      FIG. 1  is a schematic diagram of a system for dynamic wheel diameter determination according to one or more embodiments; 
           [0005]      FIG. 2  is a graphical representation of signals indicating detection and loss of detection according to one or more embodiments; 
           [0006]      FIG. 3  is a flow chart for a method of dynamic wheel diameter determination according to one or more embodiments; and 
           [0007]      FIG. 4  is a block diagram of a controller usable in accordance with one or more embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0008]      FIG. 1  is a diagram of a system  100  for dynamic wheel diameter determination in accordance with one or more embodiments. System  100  comprises a vehicle  102  moving along a direction of motion  104 . In some embodiments, vehicle  102  moves along a guideway  106 . Vehicle  102  comprises at least one wheel  108  having a diameter D, at least one sensor  110 , and at least one signal generator  112 . 
         [0009]    System  100  further comprises a first proximity plate  114  and a second proximity plate  116  arranged along direction of motion  104 . First proximity plate  114  has a first length d 1  and is positioned at a first location L 1  along direction of motion  104 . First length d 1  extends longitudinally along direction of motion  104 . First proximity plate  114  and second proximity plate  116  are separated by a second length d 2  along direction of motion  104 . 
         [0010]    Second proximity plate  116  has a third length d 3  and is positioned at a second location L 2  along direction of motion  104 . Third length d 3  extends longitudinally along direction of motion  104 . Each of first length d 1 , second length d 2 , and third length d 3  extend longitudinally end-to-end along direction of motion  104 . First length d 1 , second length d 2 , and third length d 3  are predetermined values. 
         [0011]    In at least some embodiments, system  100  comprises only first proximity plate  114  and lacks second proximity plate  116 . In other embodiments, system  100  comprises first proximity plate  114 , second proximity plate  116 , and at least one additional proximity plate. 
         [0012]    Accuracy is increased with increasing numbers of proximity plates; however, cost and space requirements increase also. The use of two proximity plates instead of one allows for significant accuracy improvement while reducing cost and space burdens. 
         [0013]    System  100  further comprises a controller  118 . In some embodiments, controller  118  is located on-board vehicle  102 . In other embodiments, controller  118  is located on-board another vehicle attached to vehicle  102 . In some embodiments, controller  118  is located at a stationary position and not on-board a vehicle. 
         [0014]    In some embodiments, system  100  further comprises a first signaling device  120  positioned at a location L 3  along direction of motion  104 . In some embodiments, system  100  includes a second signaling device  122  positioned at a location L 4  along direction of motion  104 . 
         [0015]    In some embodiments, vehicle  102  is part of a train. In some embodiments, vehicle  102  is a train. In some embodiments, vehicle  102  is configured to carry passengers. In some embodiments, vehicle  102  is configured to carry freight. In some embodiments, vehicle  102  is capable of being remotely operated by a driver not present on the vehicle. 
         [0016]    In some embodiments, vehicle  102  moves along guideway  106  and direction of motion  104  is bi-directional. In some embodiments, direction of motion  104  is any direction with respect to the ground or other path along which vehicle  102  moves. 
         [0017]    Guideway  106  is configured to control a travel path of vehicle  102 . In some embodiments, guideway  106  is a dual rail guideway including two rails spaced apart from one another. In some embodiments, guideway  106  is a monorail guideway including a single rail. 
         [0018]    Wheel  108  is located on vehicle  102  and is configured to facilitate motion of vehicle  102  along at least one direction of motion  104 . In various embodiments, vehicle  102  includes any number of other wheels in addition to wheel  108 . In some embodiments, wheel  108  is identical to other wheels on vehicle  102 . In some embodiments, wheel  108  is different from other wheels on vehicle  102 . In at least some embodiments, each wheel on vehicle  102  has a same diameter D. In at least some embodiments, one or more wheels on vehicle  102  have differing diameters. 
         [0019]    In some embodiments, wheel  108  is part of a wheel assembly attached to vehicle  102 . In some embodiments, wheel  108  is attached to an axle within a wheel assembly. In some embodiments, wheel  108  is attached to an axle held directly by vehicle  102 . 
         [0020]    Wheel  108  has at least one outside diameter D such that the outer surface or circumference of the wheel is in contact with guideway  106 . In some embodiments, wheel  108  is configured to control motion of vehicle  102  along guideway  106 . In some embodiments, wheel  108  is configured to control motion of vehicle  102  along guideway  106  by having a flange. In some embodiments, diameter D is the largest diameter of wheel  108 . 
         [0021]    Wheel  108  is constructed of any material having sufficient strength to support vehicle  102  and facilitate motion of vehicle  102  along direction of motion  104 . In some embodiments, the material is chosen from metal, rubber, plastic, or another suitable material or a combination thereof. In some embodiments, wheel  108  is or comprises stainless steel. In some embodiments, wheel  108  comprises an outer portion of rubber configured around an inner portion comprising metal. 
         [0022]    Referring to  FIG. 1  and  FIG. 2 , sensor  110  is mounted on vehicle  102  and is configured to detect first proximity plate  114  and second proximity plate  116 . Sensor  110  is configured to generate a first signal  210  indicating detection and loss of detection of first proximity plate  114  and second proximity plate  116 . In some embodiments, sensor  110  is a Hall Effect Sensor or another suitable type of magnetic metal detector. In various embodiments, vehicle  102  includes any number of other sensors in addition to sensor  110 . In some embodiments, sensor  110  is identical to other sensors on vehicle  102 . In some embodiments, sensor  110  is different from other sensors on vehicle  102 . 
         [0023]    Referring to  FIG. 1  and  FIG. 2 , signal generator  112  is positioned on vehicle  102  and is configured to generate a second signal  220  including a pulse corresponding to at least a portion of a revolution of wheel  108 . Signal generator  112  generates a predetermined number of pulses for each revolution of wheel  108 . In some embodiments, signal generator  112  is a tacho-generator mounted on an axle attached to wheel  108 . In some embodiments, signal generator  112  generates a predetermined number of pulses corresponding to a single revolution of wheel  108 . In various embodiments, the number of pulses is less than, equal to, or greater than the number of wheel revolutions. In some embodiments, the number of pulses indicates a full and fractional number of wheel revolutions. In some embodiments, a signal other than a number of pulses indicates a number of revolutions of wheel  108 . 
         [0024]    In various embodiments, vehicle  102  includes any number of other signal generators in addition to signal generator  112 . In some embodiments, signal generator  112  is identical to other signal generators on vehicle  102 . In some embodiments, signal generator  112  differs from other signal generators on vehicle  102 . 
         [0025]    In some embodiments, a proximity plate, e.g., first or second proximity plate  114 , is a metal plate configured to be detected by sensor  110  mounted on the vehicle  102 . In some embodiments, the proximity plate includes a non-magnetic material such as aluminum. In some embodiments, the proximity plate includes a magnetic material, such as iron, unfinished steel or another suitable magnetic material. 
         [0026]    In some embodiments, the proximity plate is located between rails of a split rail guideway. In some embodiments, the proximity plate is located adjacent to guideway  106  for monorail systems. In some embodiments, the proximity plate is located within guideway  106 . In some embodiments, the proximity plate is located outside rails of a split rail guideway. 
         [0027]    In some embodiments, the proximity plate has a length d 1  ranging from about 1 meter to about 1.5 meters. In some embodiments, the proximity plate has a width ranging from about 30 centimeters (cm) to about 50 cm. In still further embodiments, the proximity plate has different dimensions suitable for detection by sensor  110  given a particular rate of travel of vehicle  102 . 
         [0028]    In some embodiments, first proximity plate  114  and second proximity plate  116  have approximately the same dimensions. In some embodiments, length d 1  is substantially equal to length d 3 . In other embodiments, length d 1  is substantially different from length d 3 . In some embodiments, other dimensions of first proximity plate  114  and second proximity plate  116  differ substantially. 
         [0029]    First proximity plate  114  at location L 1  and second proximity plate  116  at location L 2  are separated by second length d 2 . In some embodiments, second length d 2  has a value ranging from about 50 cm to about 2 meters. In still further embodiments, second length d 2  is a different value suitable for detection by sensor  110  given a particular rate of travel of vehicle  102 . 
         [0030]    Controller  118  is capable of accessing predetermined values for first length d 1 , second length d 2 , and third length d 3 . In some embodiments, values for first length d 1  and third length d 3  are based on manufacturing specifications. 
         [0031]    First signaling device  120  is positioned at location L 3  along direction of motion  104 . In some embodiments, first signaling device  120  is located adjacent to guideway  106 . In some embodiments, first signaling device  120  is located between rails of a split rail guideway. In some embodiments, first signaling device  120  is located outside rails of a split rail guideway. 
         [0032]    In some embodiments, in operation, movement of vehicle  102  in direction of motion  104  causes the vehicle to pass first signaling device  120  before passing first proximity plate  114  and second proximity plate  116 . In some embodiments, first signaling device  120  is configured to initiate an on-board response as vehicle  102  passes first signaling device  120 . In some embodiments, first signaling device  120  is configured to automatically initiate an on-board response. In some embodiments, first signaling device  120  is or comprises a transponder. In some embodiments, first signaling  120  device is or comprises an RFID transponder. In other embodiments, first signaling device is a proximity plate. 
         [0033]    In some embodiments, first signaling device  120  is configured to cause an operator of vehicle  102  to manually initiate an on-board response. In some embodiments, first signaling device  120  is or comprises a sign. 
         [0034]    In some embodiments, second signaling device  122  is positioned at location L 4  along direction of motion  104 . In some embodiments, second signaling device  122  is located adjacent to guideway  106 . In some embodiments, second signaling device  122  is located between rails of a split rail guideway. In some embodiments, second signaling device  122  is located outside rails of a split rail guideway. 
         [0035]    In some embodiments, in operation, movement of vehicle  102  in direction of motion  104  causes the vehicle to pass second signaling device  122  before passing first proximity plate  116  and second proximity plate  114 . In some embodiments, second signaling device  122  is configured to initiate an on-board response as vehicle  102  passes second signaling device  122 . In some embodiments, second signaling device  122  is configured to automatically initiate an on-board response. In some embodiments, second signaling device  122  is or comprises a transponder. In some embodiments, second signaling device  122  is or comprises an RFID transponder. In other embodiments, second signaling device is a proximity plate. 
         [0036]    In some embodiments, second signaling device  122  is configured to cause an operator of vehicle  102  to manually initiate an on-board response. In some embodiments, second signaling device  122  is or comprises a sign. 
         [0037]    In some embodiments, second signaling device  122  is identical to first signaling device  120 . In other embodiments, first signaling device  120  differs from second signaling device  122 . 
         [0038]    Referring to  FIG. 1  and  FIG. 2 , in some embodiments, in operation, an on-board response to first signaling device  120  or second signaling device  122  includes generation or modification of a third signal  230 . In some embodiments, controller  118  is configured to receive third signal  230 . In some embodiments, an on-board detecting device is configured to generate or modify third signal  230  in response to detecting first signaling device  120  or second signaling device  122 . In some embodiments, an on-board detecting device is configured to detect an RFID transponder as first signaling device  120  or second signaling device  122 . In some embodiments, an on-board detecting device is a sensor configured to detect a proximity plate. In some embodiments, an on-board detecting device is sensor  110 . 
         [0039]    In some embodiments, an on-board control assembly is configured to generate or modify third signal  230  in response to an input by a driver or operator of vehicle  102 . In some embodiments, in operation, the driver or operator of vehicle  102  provides the input in response to detecting, e.g., visually or audibly, first signaling device  120  or second signaling device  122 . 
         [0040]    In some embodiments, direction of motion  104  of vehicle  102  is bi-directional. Accordingly, use of the terms “first” and “second” proximity plates and signaling devices is not limited to the relative positions depicted for system  100 . In some embodiments, the term “first signaling device” designates either one of two signaling devices, “first” indicating that a vehicle passes a particular signaling device before another depending on the specific direction of motion. Similarly, in some embodiments, the term “first proximity plate” designates either one of two proximity plates, “first” indicating that a vehicle passes a particular proximity plate before another depending on the specific direction of motion. 
         [0041]    Controller  118  is configured to receive first signal  210  from sensor  110 , second signal  220  from signal generator  112 , and determine diameter D based on detection and loss of detection of first proximity plate  114 , first length d 1 , and the number of revolutions of wheel  108 . In some embodiments, controller  118  is configured to determine diameter D based on detection and loss of detection of second proximity plate  116 , second length d 2 , and third length d 3 , as well as detection and loss of detection of first proximity plate  114 , first length d 1 , and the number of revolutions of wheel  108  based on the number of pulses in second signal  220  during the time interval in which the wheel traversed first length d 1 . 
         [0042]    In some embodiments, controller  118  is configured to receive signals from at least one sensor in addition to sensor  110 . In some embodiments, controller  118  is configured to receive signals from at least one signal generator in addition to signal generator  112 . In some embodiments, controller  118  is configured to determine a diameter of at least one wheel in addition to wheel  108 . 
         [0043]    Referring to  FIG. 1  and  FIG. 2 , in some embodiments, controller  118  is a vital on-board controller (VOBC). In some embodiments, controller  118  is connected to automatic speed control which is configured to adjust the speed of vehicle  102 . In some embodiments, controller  118  is integrated with the automatic speed control so that controller  118  directly controls a thrust and braking of vehicle  102 . In some embodiments, controller  118  is capable of generating coast mode signal  240  to place vehicle  102  in a coast mode in which no thrusting or braking is applied. 
         [0044]    In various embodiments, vehicle  102  includes any number of other controllers in addition to controller  118 . In some embodiments, controller  118  is identical to other controllers on vehicle  102 . In some embodiments, controller  118  is different from other controllers on vehicle  102 . 
         [0045]    Referring to  FIG. 2 , first signal  210  indicates detection and loss of detection of first proximity plate  114  and second proximity plate  116 , if present. In the example embodiment depicted in  FIG. 2 , first signal  210  indicates detection and loss of detection of a proximity plate as transitions between two values. In various embodiments, first signal  210  is any combination of signal and signal modification scheme capable of indicating detection and loss of detection of a proximity plate. 
         [0046]    In the example embodiment depicted in  FIG. 2 , detection of first proximity plate  114  is indicated at time T 2 , loss of detection of first proximity plate  114  is indicated at time T 3 , detection of second proximity plate  116  is indicated at time T 4 , and loss of detection of second proximity plate  116  is indicated at time T 5 . 
         [0047]    Second signal  220  indicates the number of revolutions of wheel  108 . In the example embodiment depicted in  FIG. 2 , second signal  220  indicates the number of revolutions as a series of pulses in which a predetermined number of pulses corresponds to a single revolution of wheel  108 . In various embodiments, second signal  220  is a combination of signal and signal modification scheme capable of indicating a full and/or fractional number of revolutions of a wheel. 
         [0048]    In the example embodiment depicted in  FIG. 2 , second signal  220  is a series of uniform pulses corresponding to a constant rate of revolution of wheel  108 . In various embodiments, second signal  220  includes a time-varying component corresponding to a variation in the rate of revolution of wheel  108 . 
         [0049]    Third signal  230  indicates the detection of first signaling device  120  and second signaling device  122 , if present. In the example embodiment depicted in  FIG. 2 , third signal  230  indicates detections of signaling devices as transitions between two values. In various embodiments, third signal  230  is any combination of signal and signal modification scheme capable of indicating detection of a signaling device. 
         [0050]    In the example embodiment depicted in  FIG. 2 , detection of first signaling device  120  is indicated at time T 0  and detection of second signaling device  122  is indicated at time T 6 . 
         [0051]    In some embodiments, third signal  230  is either not present or not used. In some embodiments in which third signal  230  is either not present or not used, first signaling device  120  is a proximity plate and detection of first signaling device  120  is indicated by first signal  210 . In some embodiments in which third signal  230  is either not present or not used, first signaling device  120  is a sign and a driver or operator indicates detection of first signaling device  120  through a manual input. 
         [0052]    Coast mode signal  240  indicates control of thrusting and braking of vehicle  102 . Coast mode “on” indicates that no thrusting or braking is applied so that wheel  108  is rolling and not slipping or sliding. In the example embodiment depicted in  FIG. 2 , coast mode signal  240  indicates start and stop of coast mode as transitions between two values. In various embodiments, coast mode signal  240  is any combination of signal and signal modification scheme capable of indicating application of a coast mode. 
         [0053]    In some embodiments, application of a coast mode is achieved manually by a driver or operator of vehicle  102  and coast mode signal  240  is either not present or not used. 
         [0054]    Coast mode “off” indicates any control status of vehicle  102  other than the combination of no thrusting or braking of coast mode. 
         [0055]    Controller  118  is configured to receive first signal  210 , second signal  220 , and third signal  230 , if present. In some embodiments, controller  118  is configured to execute a first response upon receipt of an indication of detection of first signaling device  120  in third signal  230 . In some embodiments, controller  118  is configured to execute the first response upon receipt of an indication of detection of first signaling device  120  in first signal  210 . In some embodiments, the first response includes outputting a coast mode “on” indication in coast mode signal  240 . In some embodiments, the first response includes monitoring first signal  210  for indications of detection and loss of detection of a proximity plate. 
         [0056]    In some embodiments, controller  118  is configured to execute a second response upon receipt of an indication of detection of second signaling device  122  in third signal  230 . In some embodiments, controller  118  is configured to execute the second response upon receipt of an indication of detection of second signaling device  122  in first signal  210 . In various embodiments, controller  118  is configured to execute the second response upon receipt of an indication in first signal  210  of loss of detection of first proximity plate  114 , second proximity plate  116 , or another proximity plate. In some embodiments, controller  118  is configured to execute the second response upon receipt of an input other than first signal  210  or third signal  230 . 
         [0057]    In some embodiments, the second response includes outputting a coast mode “off” indication in coast mode signal  240 . In some embodiments, the second response includes initiating a determination of wheel diameter D. In some embodiments, initiating a determination of wheel diameter D includes invoking a software algorithm. 
         [0058]    Controller  118  is configured to determine diameter D of wheel  108  based on at least first length d 1 , detection and loss of detection of first proximity plate  114 , and the number of revolutions of wheel  108  based on the number of pulses in second signal  220  during the traversal of first length d 1  by the wheel. 
         [0059]    For a given interval of time, the number of revolutions, NRV, of wheel  108  is obtained from the number of pulses in second signal  220  during the particular time interval. In the embodiment depicted in  FIG. 2 , the number of revolutions is given by: 
         [0060]    NRV=(number of pulses in interval)/(number of pulses per revolution) In other embodiments, NRV is determined by any method consistent with the method used to indicate number of revolutions in second signal  220 . Diameter D is therefore given by: 
         [0000]        D =(distance traveled in interval)/(π* NRV )
 
         [0061]    In the embodiment depicted in  FIG. 2 , times T 2  and T 3  define the interval for detection and loss of detection of first proximity plate  114 . For this interval, the distance traveled is the known value of first length d 1 . Diameter D in this case is calculated as: 
         [0000]        D=d 1/(π* NRV  from  T 2 to  T 3)
 
         [0000]    In some embodiments this calculation is used to determine diameter D of wheel  108 . 
         [0062]    In some embodiments, additional calculations are made for additional time intervals as defined by times T 2 , T 3 , T 4 , and T 5 . The following time intervals and corresponding distances apply: 
         [0063]    T 2  to T 3 : d 1   
         [0064]    T 3  to T 4 : d 2   
         [0065]    T 4  to T 5 : d 3   
         [0066]    T 2  to T 5 : d 1 +d 2 +d 3   
         [0067]    T 2  to T 4 : d 1 +d 2   
         [0068]    T 3  to T 5 : d 2 +d 3   
         [0069]    Because d 1 , d 2 , and d 3  have known values, calculation of distance traveled for each of the six combinations is straightforward, and diameter D is capable of being determined based on the number of revolutions of wheel  108  over the corresponding time interval. 
         [0070]    In some embodiments, controller  118  is configured to determine diameter D by averaging at least two diameter calculations based on different time intervals. In some embodiments, controller  118  is configured to determine diameter D by averaging six diameter calculations based on six different time intervals. Averaging six calculations improves accuracy by canceling out delays in detection and loss of detection of proximity plates. 
         [0071]    In a particular embodiment in which six calculations are averaged, individual calculations Dx are given by: 
         [0000]        D 1= d 1/(π* NRV  from  T 2 to  T 3)
 
         [0000]        D 2= d 2/(π* NRV  from  T 3 to  T 4)
 
         [0000]        D 3= d 3/(π* NRV  from  T 4 to  T 5)
 
         [0000]        D 4= d 1+ d 2+ d 3/(π* NRV  from  T 2 to  T 5)
 
         [0000]        D 5= d 1+ d 2/(π* NRV  from  T 2 to  T 4)
 
         [0000]        D 6= d 2+ d 3/(π* NRV  from  T 3 to  T 5)
 
         [0072]    Diameter D is then determined from the individual calculations: 
         [0000]        D =( D 1+ D 2+ D 3+ D 4+ D 5+ D 6)/6 
         [0073]    By averaging over multiple intervals defined by different combinations of detection and loss of detection of proximity plates, measurement error is reduced. Proximity plate detection involves sensor activation while loss of detection involves sensor de-activation. The use of multiple readings with different activation and de-activation operating domains is used to eliminate the sensor errors corresponding to each operating domain. 
         [0074]    The present description also concerns a method of dynamic wheel diameter determination. An example embodiment of a method  300  of dynamic wheel diameter determination is depicted in  FIG. 3 . Various embodiments include some or all of the steps depicted in  FIG. 3 . 
         [0075]    In step  302 , a coast mode is initiated for a vehicle. In coast mode, no thrusting or braking is applied so that a wheel of the vehicle is rolling and not slipping or sliding. Coast mode is initiated by detection of a first signaling device. In some embodiments, coast mode is initiated automatically through automatic detection of the first signaling device. In some embodiments, coast mode is initiated manually by a driver or operator of the vehicle upon detection of the first signaling device. 
         [0076]    In step  304 , a sensor on the vehicle generates a first signal. The first signal indicates detection and loss of detection of a first proximity plate having a first length and positioned at a first location along a direction of motion of the vehicle. In some embodiments, the first signal indicates detection and loss of detection of a second proximity plate having a second length, positioned at a second location along the direction of motion of the vehicle. A known third length separates the first location and second location. 
         [0077]    In some embodiments, the first signaling device is a proximity plate and the first signal indicates detection of the first signaling device. In some embodiments, the second signaling device is a proximity plate and the first signal indicates detection of a second signaling device. 
         [0078]    In some embodiments, the sensor continuously generates the first signal. In other embodiments, the sensor generates the first signal in response to detection of at least one of the first proximity plate, second proximity plate, first signaling device, and second signaling device. 
         [0079]    In step  306 , a signal generator on the vehicle generates a second signal. The second signal indicates a number of revolutions of a wheel on the vehicle. In some embodiments, the signal generator is a tacho-generator. In some embodiments, the second signal indicates the number of revolutions of the wheel through a series of pulses, a predetermined number of pulses corresponding to a single revolution of the wheel. 
         [0080]    In some embodiments, the signal generator sensor continuously generates the second signal. In other embodiments, the signal generator generates the second signal in response to an input. 
         [0081]    In step  308 , a controller receives the first signal and second signal. In some embodiments, the controller receives the first signal through a direct path on-board the vehicle. In some embodiments, the controller receives the second signal through a direct path on-board the vehicle. In some embodiments, the controller receives one or both of the first signal and the second signal over a wireless connection. 
         [0082]    In some embodiments, the controller continuously receives one or both of the first signal and the second signal. In some embodiments, the controller receives one or both of the first signal and the second signal in response to an input. 
         [0083]    In step  310 , vehicle coast mode is terminated. In some embodiments, coast mode is terminated automatically through automatic detection of a second signaling device. In some embodiments, coast mode is terminated manually by the driver or operator of the vehicle. 
         [0084]    In step  312 , a diameter of the wheel is determined by the controller. Determining the diameter is based on the first length, the detection and loss of detection of the first proximity plate, and the number of revolutions of the wheel. In some embodiments, determining the diameter is also based on the second length, the third length, and detection and loss of detection of the second proximity plate. In some embodiments, determining the diameter includes averaging at least two separate diameter calculations based on detection and loss of detection events and the number of revolutions of the wheel. In some embodiments, determining the diameter includes averaging six separate diameter calculations based on detection and loss of detection events and the number of revolutions of the wheel. 
         [0085]    In some embodiments, determining the diameter is initiated by detection of the second signaling device. In some embodiments, determining the diameter is initiated by the loss of detection of the first or second proximity plate. 
         [0086]      FIG. 4  is a block diagram of a controller  400  configured for dynamic wheel diameter determination in accordance with one or more embodiments. In some embodiments, controller  400  is an on-board controller for a vehicle. In some embodiments, controller  400  is similar to controller  118  ( FIG. 1 ). Controller  400  includes a hardware processor  402  and a non-transitory, computer readable storage medium  404  encoded with, i.e., storing, the computer program code  406 , i.e., a set of executable instructions. Computer readable storage medium  404  is also encoded with instructions  407  for interfacing with elements of VOBC  400 . The processor  402  is electrically coupled to the computer readable storage medium  404  via a bus  408 . The processor  402  is also electrically coupled to an I/O interface  410  by bus  408 . A network interface  412  is also electrically connected to the processor  402  via bus  408 . Network interface  412  is connected to a network  414 , so that processor  402  and computer readable storage medium  404  are capable of connecting and communicating to external elements via network  414 . In some embodiments, network interface  412  is replaced with a different communication path such as optical communication, microwave communication, inductive loop communication, or other suitable communication paths. The processor  402  is configured to execute the computer program code  406  encoded in the computer readable storage medium  404  in order to cause controller  400  to be usable for performing a portion or all of the operations as described with respect to dynamic wheel diameter determination system  100  ( FIG. 1 ) or a method  300  ( FIG. 3 ). 
         [0087]    In some embodiments, the processor  402  is a central processing unit (CPU), a multi-processor, a distributed processing system, an application specific integrated circuit (ASIC), and/or a suitable processing unit. In some embodiments, processor  402  is configured to receive detection and loss of detection information signals and number of wheel revolutions information signals via network interface  412 . In some embodiments, processor  402  is configured to generate vehicle control information signals for transmitting to external circuitry via network interface  412 . 
         [0088]    In some embodiments, the computer readable storage medium  404  is an electronic, magnetic, optical, electromagnetic, infrared, and/or a semiconductor system (or apparatus or device). For example, the computer readable storage medium  404  includes a semiconductor or solid-state memory, a magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk, and/or an optical disk. In some embodiments using optical disks, the computer readable storage medium  404  includes a compact disk-read only memory (CD-ROM), a compact disk-read/write (CD-R/W), and/or a digital video disc (DVD). In some embodiments, the computer readable storage medium  404  is part of an embedded microcontroller or a system on chip (SoC). 
         [0089]    In some embodiments, the storage medium  404  stores the computer program code  406  configured to cause controller  400  to perform the operations as described with respect to dynamic wheel diameter determination system  100  ( FIG. 1 ) or method  300  ( FIG. 3 ). In some embodiments, the storage medium  404  also stores information needed for performing the operations as described with respect to dynamic wheel diameter determination system  100 , such as a first length parameter  416 , a second length parameter  418 , a third length parameter  420 , a pulses per revolution parameter  422 , and/or a set of executable instructions to perform the operation as described with respect to dynamic wheel diameter determination system  100 . 
         [0090]    In some embodiments, the storage medium  404  stores instructions  407  for interfacing with external components. The instructions  407  enable processor  402  to generate operating instructions readable by the external components to effectively implement the operations as described with respect to dynamic wheel diameter determination system  100 . 
         [0091]    Controller  400  includes I/O interface  410 . I/O interface  410  is coupled to external circuitry. In some embodiments, I/O interface  410  is configured to receive instructions from a port in an embedded controller. 
         [0092]    Controller  400  also includes network interface  412  coupled to the processor  402 . Network interface  412  allows Controller  400  to communicate with network  414 , to which one or more other computer systems are connected. Network interface  412  includes wireless network interfaces such as BLUETOOTH, WIFI, WIMAX, GPRS, or WCDMA; or wired network interface such as ETHERNET, USB, IEEE-1394, or asynchronous or synchronous communications links, such as RS485, CAN or HDLC. In some embodiments, the operations as described with respect to Controller  400  are implemented in two or more wheel diameter determining systems, and information such as first length, second length, third length, and number of revolutions are exchanged between different Controller  400  via network  414 . 
         [0093]    Controller  400  is configured to receive information related to a first length from a user or an external circuit. The information is transferred to processor  402  via bus  408  and stored in computer readable medium  404  as first length parameter  416 . Controller  400  is configured to receive information related to a second length from a user or an external circuit. The information is transferred to processor  402  via bus  408  and stored in computer readable medium  404  as second length parameter  418 . Controller  400  is configured to receive information related to a third length from a user or an external circuit. The information is transferred to processor  402  via bus  408  and stored in computer readable medium  404  as third length parameter  420 . Controller  400  is configured to receive information related to a number of tacho-generator pulses per revolution of a wheel from a user or an external circuit. The information is transferred to processor  402  via bus  408  and stored in computer readable medium  404  as pulses per revolution parameter  422 . 
         [0094]    During operation, processor  402  executes a set of instructions to determine wheel diameter as described with respect to dynamic wheel diameter determination system  100  ( FIG. 1 ) or method  300  ( FIG. 3 ). 
         [0095]    Although the embodiments and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, and composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. 
         [0096]    It will be readily seen by one of ordinary skill in the art that the disclosed embodiments fulfill one or more of the advantages set forth above. After reading the foregoing specification, one of ordinary skill will be able to affect various changes, substitutions of equivalents and various other embodiments as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by the definition contained in the appended claims and equivalents thereof.