Abstract:
A system for determining road quality includes a vehicle equipped with sensors to detect a position of the vehicle on the road and a suspension strut parameter indicative of road quality. The suspension strut parameter may be suspension strut pressure or suspension strut cylinder stroke. A threshold range is established outside of which the suspension strut parameter is associated with poor road quality. A computerized system implementing this method is capable of automating requests for inspection and maintenance of the road, as well as generating maps indicating sections of the road according to their relative quality. The system may be implemented for use by heavy equipment type commonly used in mining operations, or in context of other operations utilizing fleets of vehicles that commonly traverse publicly or privately maintained roads.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims benefit of priority to U.S. provisional patent application No. 62/267,518 filed Dec. 15, 2015, which is hereby incorporated by reference the same extent as though fully replicated herein. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The presently disclosed instrumentalities relate to systems and methods of managing vehicle travel in general and, more particularly, to systems and methods of utilizing vehicle to assess road quality. 
         [0004]    2. Description of the Related Art 
         [0005]    Open pit mines utilize fleets of specialized vehicles that are specially adapted for heavy haul utilization. These vehicles include, for example, the Model 793F, 797F and MT4400D AC vehicles manufactured by Caterpillar of Peoria, Ill., which have nominal payload capacities ranging from 221 to 363 metric tonnes. These vehicles may be purchased on commercial order equipped with controller area network (CAN) systems. 
         [0006]    Data from heavy haul vehicles may be broadcast for use at a monitoring station. This is shown, for example, in U.S. Pat. No. 7,987,027, which shows use of CAN technology on mining vehicles. A wireless transmission system provides for data download/upload functionality to an off-board monitoring system. The wireless transmission system preprocesses acquired machine data and combines data sets to reduce bandwidth in accommodating low-frequency, low bandwidth networks of a type commonly used in mines. 
         [0007]    CAN systems such as these provide an overwhelming amount of data concerning the status of various vehicle components. System readings may include, without limitation, what gear the vehicle is operating in at a particular time; compositional analysis of engine exhaust contents such as soot, fuel vapor, carbon monoxide and the like; pressure differentials across such engine components as filters, blowers and the like; tire pressure; alternator output; battery voltage; temperatures including coolant temperature, oil temperature, cab temperature, brake temperature, external temperature and the like; intervals of brake activation; intervals of acceleration and deceleration; windshield wiper activation; grade of road; steering patterns indicative of operator fatigue; hydraulic pump output pressure; quantity of fuel on board, and suspension strut gas pressure. Utilization of this data is typically directed towards analytics for maintenance needs or monitoring of individual vehicles to assure operations within parameters as required under vehicle warranty. Generally speaking, the analytics have not progressed beyond these factors to facilitate improved fleet operations. 
       SUMMARY 
       [0008]    The presently disclosed instrumentalities overcome the problems outlined above and advance the art by providing transport vehicle diagnostics that may be utilized to improve vehicle fleet operations. In particular, the vehicle diagnostics include assessing road quality to recommend and/or automate road maintenance operations. 
         [0009]    According to one embodiment, a method of determining road quality includes traversing the road with a vehicle. As this happens a position of the vehicle is tracked as the vehicle traverses one or more segments of the road. A suspension strut parameter of the vehicle is also tracked in association with the vehicle position as the vehicle traverses the road. A threshold range of the suspension strut parameter is established such that values outside of this threshold range indicate of poor road quality. A determination is then made of instances where an absolute value of the suspension strut parameter exceeds the threshold value as an indicator of poor road quality associated with a portion of the road. The road quality may then be reported for road inspection and/or maintenance operations to occur. 
         [0010]    In one aspect, the foregoing method may be implemented utilizing program logic in a network system. The system includes a vehicle having at least one suspension strut. A sensor is operatively associated with the suspension strut of the vehicle for sensing a suspension strut parameter indicative of road quality. A position sensor is operatively associated with the vehicle for determining a position of the vehicle on the road. A vehicle network mounted on the vehicle is operatively configured for transmitting output representative of the suspension strut parameter and the position of the vehicle. A telecommunications network is constructed and arranged for communicating data between the vehicle network and a central computing location. The vehicle network and the central computing location are provided with program logic for implementing the method. 
         [0011]    In one aspect, a non-transitory computer-readable storage medium has computer-executable attractions embodied thereon that, when executed by at least one computer processor cause the processor to execute the foregoing method. The non-transitory computer-readable storage medium may be, for example, a computer hard drive, a flash memory stick, or a CD-ROM. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Illustrative and presently preferred exemplary embodiments of the invention are shown in the drawings in which: 
           [0013]      FIG. 1  is a schematic representation of one embodiment of a system for assessing road quality according to the presently disclosed instrumentalities; 
           [0014]      FIG. 2  shows a vehicle network that may be used to equip one or more of the vehicles of  FIG. 1 ; 
           [0015]      FIG. 3  additional details of the vehicle network concerning a strut pressure sensor, a position sensor, the transceiver, and the vehicle network; 
           [0016]      FIG. 4  is a flow chart of one embodiment of a method of determining road quality by use of suspension strut parameter data where the method of  FIG. 4  may be implemented as software programming a computer with machine instructions for the performance of this method; 
           [0017]      FIG. 5  shows a mining road that is subjected to road quality determinations utilizing a fleet of vehicles operating according to the method of  FIG. 3 ; 
           [0018]      FIG. 6  is a plot of suspension strut pressure versus position on the road of  FIG. 5  with the plot is annotated to show various analytical aspects in the assessment of road quality; and 
           [0019]      FIG. 7  is a heat map that may be generated to illustrate road quality determinations on a relative scale produced by the method of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1  shows one embodiment of a system  100  used to determine road quality on the basis of measurements obtained by one or more vehicles, such as haul trucks  102 ,  104 ,  106 ,  108 ,  110 . Each of the haul trucks  102 - 110  is equipped with a two-way wireless communications linkage, such as linkages  112 ,  114  respectively incorporated in haul tucks  108 ,  110 . The linkages  112 ,  114  are in wireless communications with one or more wireless access points  116 , such as a radio tower or a Bluetooth Scatternet, which is constructed and arranged to provide wireless communications from a remote location such as an open pit mine or lumbering operation. The wireless access point  116  communicates data to and from a server/router combination  118 / 120 . The router  120  processes packetized communications from the remote location through satellite dish  122 , utilizing communications linkage  124  to communicate with a satellite network  126 . The satellite network  126  communicates through commercial linkages  128  established by one or more commercial service providers to gain access to the Internet  130  for communication with router/server combination  132 / 134 . Data from server  134  are accordingly provided to computer  136  and stored on database  140 . It will be appreciated that the computer  136  with associated display  138  and database  140  may be located at a central location, but also that the associated computing and data storage functionalities described below may be distributed, as in the case of distributed databasing and/or massively parallel computing. Moreover, the network design may vary by methods known to the art to accommodate an infinite number of hardware choices based upon the need of any particular location. For example, the satellite  126  is unnecessary if there is a different telecommunications network available, or if the central computer  136  is located at a remote location such as a mine. There may be any number of haul trucks  102 - 110 , and the computer  136  may be used to monitor more than one remote location. 
         [0021]    The haul trucks  102 - 110  form a fleet of trucks in used at a particular location, such as a mine where the trucks are utilized to haul earthen materials from the mine. Each of these trucks are equipped with a vehicle network (not shown). The respective vehicle networks provide data sense and reporting functionalities that facilitate monitoring of vehicle components. Vehicle networks include, for example, Local Interconnect Networks (“LIN;” see ISO 9141 and ISO 17987) suited for low date rate applications, CAN (see ISO11898) for medium data rate applications; and FlexRay (ISO 17458) for safety critical applications. A haul truck may contain more than one vehicle network. 
         [0022]    Commercially available vehicle networks most frequently operate using the CAN protocol. CAN is a multi-master serial bus standard for connecting Electronic Control Units, which function as nodes on the CAN. Two or more nodes are required on the CAN network to communicate. The node may be a simple I/O device or an embedded computer with a CAN interface and sophisticated software. The node may also be a gateway allowing a standard computer to communicate over a USB or Ethernet port to the devices on a CAN network. CANs have been used to monitor sensors in a variety of application including, without limitation, brake sensors, wheel sensors, pitch/roll/yaw sensors, fluid level sensors (fuel, oil, hydraulic fluid, etc.), hydraulic cylinder position sensors, truck bed position sensors, bucket/blade/implement position sensors, tire health sensors (pressure, temperature, tread, etc.), exhaust sensors (temperature, NOx, etc.), engine sensors (engine speed, engine load, fuel pressure, boost pressure, etc.), transmission sensors (gear, input/output speed, slip times, etc.), torque converter sensors (input speed, output speed, temperature, etc.), various other machine parameter sensors (payload, strut pressure, machine speed, etc.), and various operator cabin sensors (vibration, ignition key presence/position, seat position, seat belt position, door position, and settings/positions of operator controls, etc.). 
         [0023]      FIG. 2  shows a network schematic that represents individual vehicle networks found on each of the haul trucks  102 - 110 . As illustrated, the network  200  is a controller area network (“CAN”), but in alternative embodiments may also be a LIN, MOST, FlexRay or other type of vehicle network. 
         [0024]    Network  200  is a multi-master network utilizing the CAN multi-master architecture as is standardized in the art. Each node, such as nodes  202 ,  204 ,  206 ,  208   210 ,  212 , includes a node controller and a transceiver configured to receive and transmit data on a CAN Bus-line including CANB component  214  and CANH component  216 . The components  214 ,  216  are useful in arbitrating to resolve or arbitrate data low priority versus high priority data transmission conflicts as is known to the art. Each node of nodes  202 - 212  is configured to provide a particular functionality. Thus, node  202  provides sensor output indicative of vehicle speed. This may be done, for example, by measuring revolutions per minute (rpm) as the rotational speed of a wheel or transaxle using a magnetic pickoff that counts the incidents of magnetic field proximity variations proximate a sensor over an interval of time as an indicator of vehicle speed. As an alternative way to assess vehicle speed, node  202  may provide output indicating vehicle speed as represented on an operator&#39;s dashboard display, where the vehicle speed may be determined by any system known to the art. Node  204  is a transceiver configured to transmit and receive data on system  100 . Node  206  may provide output from a positon sensor, such as a Global Positioning System (GPS) or other wireless positioning system, such as a pseudolite system or RFID system, to associate vehicle location with a particular time. Alternatively, the position sensor may be an odometer. Node  208  includes a digital clock or timing circuit that may provide a time stamp for any data transmission on network  200 . Node  210  provides output representing a vehicle strut pressure. A processing node  212  may filter, delimit, screen or operate on data transmitted for the purposes described herein. 
         [0025]    As will be appreciated by those of ordinary skill in the art, the network  200  is not strictly limited to the nodes shown in  FIG. 2 , nor is it necessary that the network  200  have all of the nodes shown in  FIG. 2 . By way of example, network  200  may also comprise one or more environmental sensors (not shown), for example, including light sensors, rain sensors, fog sensors, and night sensors as described in European Patent Publication EP19980956367 to Schofield et al., These sensors may be utilized as CAN nodes for sensing certain environmental conditions, such as the presence of rain, snow, or fog, at various locations within the environment. All types of data on the network  200  may be transmitted on system  100  (see  FIG. 1 ). The processing node  212  may also operatively connect to one or more display systems (not shown) to display certain information and data to a driver. It is possible to utilize CAN-based technology to monitor virtually every operational aspect of a vehicle. 
         [0026]      FIG. 3  provides additional information concerning a sensor system  300  that may be utilized for the instrumentalities described herein according to one embodiment. Each of the vehicles  102 - 110 , such as vehicle  110  as shown in  FIG. 3 , may have a sensor system as shown in  FIG. 3 . A vehicle suspension system  302  is equipped with a plurality of struts  304 , which may be of the gas-liquid variety such as nitrogen-oil. A pressure sensor of node  210  is positioned in the strut to produce output representative of the strut pressure. The pressure sensor may be, for example, a force collector type of sensor such as a piezoresistive strain gauge, variable capacitive diaphragm, variable electromagnetic diaphragm, piezoelectric, or potentiometric wiper. Sensor output is preferably digitized for transmission on the vehicle network  200 . Also connected to the vehicle network  200  is the positon sensor node  206 , which is configured to provide a position of the vehicle. This may be done, for example, by use of GPS or odometer readings. The positon and pressure data are transmitted on the transceiver node  204  over communications link  112  to network  130  for use as described in context of  FIG. 1 . 
         [0027]    It will be appreciated that pressure monitoring is an optional but preferable way of monitoring the status of struts on a heavy haul vehicle. Where, for example, the effective front cylinder stoke of a Caterpillar 793F is about 13 cm (about 5.1 inches) and the rear effective stroke is about 10.7 cm (about 4.2 inches), it is alternatively possible to monitor cylinder stroke position as an indicator of force applied to the respective cylinders commensurate with a responsive cylinder pressure change. It is also possible to utilize an accelerometer located proximate a strut to produce signals representative of applied force commensurate with a responsive pressure change. As used herein, unless specifically stated otherwise, a “suspension strut parameter” includes at least the actual pressure of a strut, strut cylinder motion, and an accelerometer reading indicative of strut motion. 
         [0028]      FIG. 4  shows program logic implementing a method  400  of determining road quality for use as described herein. The program logic may be implemented, for example, on computer  136  of system  100  and/or the processing node  212  of network  200 . This is shown, by way of example, in context of a remote location  500  including mine road  502 , as shown in  FIG. 5 . Road  502  extends between a dump site at location C 1  and proceeds to a loading point at location C 24 . Transceivers  504 ,  506 ,  508 ,  510 ,  512 ,  514 ,  516 ,  518 ,  520  form part of an optional pseudo-satellite system (the transceivers being referred to as pseudo-lites) that provides positional tracking of vehicles at the remote location  500 . The pseudo-lite system may be, for example, a system as described in U.S. Pat. No. 6,031,487 issued to Mickelson. 
         [0029]    The system and method of the presently disclosed instrumentalities may be used to advantage to determine road quality ‘on-the-fly’ and with the actual vehicles and vehicle types that use of road  502  during normal operations. This advantageously dispenses with a requirement to disrupt normal operations in order to conduct a separate survey or evaluation of the road surface. Moreover, the system and method may allow for substantially continuous determination of road quality. This affords system operators with a substantially real-time evaluation of road quality changes. System operators may be able to monitor changes road quality in real time, which allows road maintenance and repair operations to be scheduled appropriately depending upon how quickly the quality of a particular segment of the road may be degrading. For example, rapid degradations in road quality may be addressed immediately, whereas slowly degrading road segments may be scheduled for maintenance at a regularly scheduled time. 
         [0030]    Referring now primarily to  FIG. 4 , a first step of method  400  may entail tracking  402  the position of any of vehicles  102 - 110 , such as vehicle  110 , as vehicle traverses road  502  (see  FIG. 5 .). In this regard, it should be noted that the system and method may determine the road quality based upon movement of a single vehicle over road  502 . Alternatively, and in many embodiments, it is optional but preferable to determine the road quality based on movements of multiple vehicles  102 - 110  over road  502 . Utilization of multiple vehicles allows for more accurate road quality determinations to be made. This increases the frequency at which changes in road quality are detected, allowing for substantially real-time assessment and tracking of road quality during actual road use. Positioning of the fleet of vehicles  102 - 110  may be determined utilizing the position sensor of node  206  as described above in context of  FIGS. 2  and, which allows the position data to be conveyed to computer  136  through network  130  (see  FIG. 1 ). The position data may be transmitted in real time or, alternatively, periodically in batch mode. 
         [0031]    Vehicle position data may be collected and/or updated on a substantially continuous basis. In most mining operations, however, the vehicle speeds are comparatively low. For example, speeds may average something less than about 32 km/h (about 20 mi/h), which is approximately 9 m/s (about 30 ft/s). Therefore, bandwidth may be preserved by sampling less frequently. By way of example, in one embodiment, the vehicle position data may be updated about once per second. 
         [0032]    The position sensor of node  210  made be any one of a wide range of sensors and sensing systems that are known to the art. Any type of positioning sensor may be utilized, such as a global positioning system (GPS) sensor. This also possible to use an odometer reading to assess position on road  502  when the distance of road  502  is known. 
         [0033]    Step  404  entails measuring at least one suspension strut parameter as a vehicle, such as vehicle  110 , traverses road  502 . The suspension strut parameter may be utilized by computer  136  (see  FIG. 1 ) to determine localized quality of road  502  as the road  502  is being traversed by vehicle. This suspension strut parameter may be the actual pressure in at least one strut  304  as shown in  FIG. 3 . As discussed above, the suspension strut parameter may alternatively be an accelerometer reading or a determination of strut cylinder stroke. The sensed measurements indicate suspension displacements caused by bumps and uneven surfaces of road  502 . The suspension strut parameter data may be transmitted over network  130  to facilitate, for example, road quality analytics that may be performed by computer  136 . The suspension strut parameter data may be transmitted to computer  136  on a substantially continuous basis, or transmission may occur periodically in batch mode. 
         [0034]    The suspension strut parameter data may be associated  406  with the vehicle location. This association of data sets allows computer  136  to determine road quality and various positions or segments along road  502 . For example, in an embodiment where the vehicle position data are updated about once per second, the computer  136  will be able to determine road quality at the same interval, i.e., about once per second. Thus, at a vehicle travel speed of about 32 km/h (about 20 mi/h or 30 ft/s), computer  136  may be capable of determining road quality about every 9 m (about 30 ft). Of course, slower travel speeds allow computer  136  to determine road quality for even shorter road segments. Alternatively, the computing may be done utilizing the processing node  212  of vehicle network  200  (see  FIG. 2 ). 
         [0035]    The data sampling rates for vehicle position in step  402  may differ from the data sampling rates for strut pressure in step  402 . In this circumstance, it is possible to broadcast all such data on network  130 , or else the data may be pre-processed on processing node  212  (see  FIG. 2 ). According to one embodiment, this pre-processing may entail, for example, averaging the strut pressure data and position date over intervals of time. These intervals of time may be the same for the strut pressure data and the positon data, or the intervals may be different. 
         [0036]    Processing step  408  entails the identification of local maxima and minima in the strut pressure data.  FIG. 6  shows the analysis for this identification by way of example. Graph  600  maps strut pressure as a function of positon on road  502 . The X-axis is provided in meters located from the start of road  502 ; however, each positon may be associated with a GPS-based latitude-longitude. The Y-axis of curve  602  represents strut pressure readings that are optionally but preferably averaged over a periodic interval of time. This interval of time may be, for example, five, ten, fifteen, twenty, twenty five or thirty seconds where the position on the X-axis represents an average position for this interval of time. Alternatively, another curve smoothing technique other than averaging may be utilized to mitigate noise and reduce the complexity of computing. 
         [0037]    Techniques known to the art, such as finite difference techniques, may be utilized to identify local maxima and minima. These local maxima and minima include, for example, minima peak  604  adjacent to maxima peak  608  and minima peak  606  adjacent to maxima peak  610 . Suitable finite difference techniques include, for example calculation of first forward differences, first backward differences, or other approximations of the local slope of curve  602  where the maxima and minima are determined as a slope of approximately  0  or where the slope transitions from a positive value to a negative value. 
         [0038]    In one type of comparison, the total magnitude of adjacent peaks may be utilized to assess poor road quality. This is shown as line  624 , which indicates the total magnitude of strut pressure between the adjacent maxima and minima peaks  606 ,  610 . In this type of comparison, step  410  entails setting a threshold, which may be accomplished by using a magnitude value that experience on a particular road or with a particular type of vehicle confirms is associated with a need for road repair. The total magnitude of line  624  may be compared to this threshold value to indicate poor road quality. Alternatively, the total magnitude of all adjacent maxima and minima peaks may be compared on a rolling basis with poor road quality being indicated by a comparative delimiter, such as a quartile ranking with road quality threshold being indicated as the top 25% in magnitude. 
         [0039]    Other comparisons may be utilized to assess poor road quality. As shown by way of example in  FIG. 6 , the curve  602  may be processed to provide a correlation  612  approximating a mean or mode of the strut pressure data. The correlation  612  may be, for example, a first-order least squares fit. It will be appreciated that in circumstances where the average strut pressure may vary on an incline or where the vehicle automatically adjusts suspension strut pressure, correlation  612  may be a multiple order or multidimensional fit where the multidimensional fit may include, for example, a third axis indicating the incline of road  502 . 
         [0040]    In this instance, step  410  then entails bounding curve  602  by a threshold, such as confidence interval  614 ,  616  to establish a threshold amplitude. The confidence interval  614 ,  616  is calculated by means known to the art and may be based upon, for example, a normal distribution, a binomial distribution, or a triangular distribution, complementary to the nature of statistical distribution of data points forming curve  602 . 
         [0041]    The range of confidence interval  614 ,  616  provides a threshold that may be utilized to assess  412  the amplitude of local maxima and minima, such as peaks  604 ,  606 ,  608 ,  610 , as an indicator of road quality. By way of example, curve  602  may be divided into a series of sequential position intervals, such as intervals  618 ,  620 ,  622  approximating 50 meters each. The interval  618  includes peaks  606 ,  610  respectively extending below and above the confidence interval  614 ,  616 . In such situations as this where a determination  414  is made that a peak falls outside the confidence interval  614 ,  616 , this indicates poor road quality  418 . This finding causes the system to initiate a bad road report  420  that optionally causes personnel to inspect  422  that interval of road  502  located at approximately 170-200 m. A decision  424  is then made whether to maintain  426  the road  502  at that interval. This decision may be made using a variety of factors, such as the severity of amplitudes outside the confidence interval  614 ,  616  and the rate of increase in this severity. 
         [0042]    Conversely, peaks  604 ,  608  fall within the confidence interval  614 ,  616  indicating good or acceptable road quality  416 . 
         [0043]    The confidence interval  614 ,  616  may be expressed as a percentage, such as a 75% confidence, and may be calculated in a variety of ways known to the art utilizing a data stream from vehicle  110 . While this is preferable it is also computationally expensive and is not strictly necessary. Alternatively, the confidence interval  614 ,  616  as discussed above may be replaced by a threshold amplitude that is experientially based as an indicator of poor road quality. One way of assessing the threshold is to ascertain characteristics of curve  602  that are associated, in actual experience, with a reduction in vehicle speed. 
         [0044]    Determination of whether an observed amplitude of maxima and minima falls outside the threshold range may be calculated as a difference where, for example, the absolute values of confidence interval line  614  is subtracted from the absolute value of the amplitude associated with peak  606 . Alternatively, it is also possible to determine the threshold that is established in step  410  as a dimensionless value calculated as the value of a ratio between the value of correlation  612  and the amplitude of local maxima and minima. Alternatively, the ratio may be determined as between the value of confidence interval boundaries  614 ,  616  and the amplitude of local maxima and minima. Any means of comparison known to the art may be utilized for this purpose. 
         [0045]    Status of road  502  is optionally but preferably flagged  416 ,  418  for reporting to computer  136 , which provides further processing  428  to create a graphical display  700  as shown by way of example in  FIG. 7 . The values may be classified on a relative scale of severity according to the amplitude of those local maxima and/or minima that exceed the confidence interval boundaries  614 ,  616  at particular positons along road  502 . Accordingly, the graphical display  700  maybe referred to as a ‘heat map’ indicating the road quality status of road  502 . By way of example, the hashing or color of section  702  may indicate that the road is of bad quality but of relatively minor severity that is not yet in need of repair. Section  704  is not specially hashed or colored, which indicates good road quality. Section  706  is specially hashed or colored to indicate a bad road quality that is in need of repair. Section  708  is specially hashed or colored to indicate that road maintenance operations are underway at that location. Logistics preceding these operations may be automated by a request emanating from computer  136  as part of process step  426 . 
         [0046]    Those of ordinary skill in the art will appreciate that the foregoing discussion may be subjected to insubstantial changes without departing from the scope and spirit of the invention. Accordingly, the inventors hereby state their intention to rely upon the Doctrine of Equivalents if needed to protect the full scope of the invention that is claimed.