Technical field

[0001] The present invention relates generally to methods and systems for monitoring road quality in underground environments.

Background art

[0002] In underground environments, where gravel roads are traveled by heavy machines, the road quality is an important factor to observe. The road quality highly affects wear on the vehicles, energy use and is furthermore a matter of safety. To ensure a sufficient road quality, without gravel pits and walls, road maintenance vehicles such as graders are sent out to level the gravel roads. A grader is a form of vehicle having a long blade used to create a flat surface by scraping or shaving the surface.

[0003] Today in underground environments it is difficult, if not impossible, to get a good overview of the road quality. The underground systems are vast and ever expanding and changing. The roads are affected by unforeseen events such as falling rocks or caving walls. Since a good overview of the road quality is practically unavailable, the graders are sent out regularly so that each segment of road in the underground environment is attended at regular intervals, instead of being based on the actual need. This approach is highly time-consuming and provides an inefficient use of resources.

[0004] Since underground roads are spatially constricted, graders and other road maintenance equipment block the use of the road segment which is being attended. Since alternative roads are rarely available underground, the access to a part of the underground environment may be completely cut off, and work in that part needs to be paused during the time the road is being attended.

[0005] There is therefore a need to improve how grading of underground road systems are performed. Summary of invention

[0006] An object of the present invention is to overcome at least some of the problems outlined above.

[0007] In a first aspect of the disclosure there is provided a method for monitoring road quality in an underground environment performed by a monitoring system, wherein the underground environment comprises infrastructure for positioning of moving objects, the method comprising: measuring, by a first sensor provided on a first moving object, a parameter indicative of road quality, determining a position of the first moving object at a time at which the measurement was performed, associating the measurement of the parameter indicative of road quality to the determined position.

[0008] The method according to the first aspect enables information relating to road quality to be collected by vehicles moving around in the underground environment. Each time a road segment is traveled by a vehicle, information relating to that road segment may be collected. By utilizing a positioning system of the underground environment, the position where the information was collected can be recorded with high accuracy. By furthermore recording the time at which the information was collected it is possible to record a change in road quality and analyze how fast the road quality changes. Other possible analyzes may comprise determining if the road quality changes during certain periods of time, or when traveled by certain vehicles. The information may be used for example to determine if road maintenance is required, how much road maintenance is required, and/or when it will be required. This increases predictability in road maintenance in the underground environment. Hence, by monitoring the road quality in the underground road systems such that road ware may be analyzed, maintenance work may be planned in an efficient way and an improved grading can be performed. By this the strain on the mining operation can be decreased.

[0009] The method according to the first aspect utilizes position determination of the first moving object. Positioning of moving objects in underground environments are often performed with high precision positioning systems because there is often a need to know a position of the moving object with a high precision essentially at all times. This in turn, is because the moving object is often associated with a high value such as a high monetary value or due to a matter of safety. As such, the position associated with the measurement of the parameter indicative of road quality according to the first aspect is determined with high precision and accuracy.

[0010] In one embodiment, measuring the parameter indicative of road quality may be performed when the first moving object is moving. In one embodiment, measuring the parameter indicative of road quality may be performed when the first moving object is standing still.

[0011] In one embodiment, measuring the parameter indicative of road quality may be performed continuously. This provides at least the advantage that the precision of the measurement increases. In one embodiment, measuring the parameter indicative of road quality may be performed discretely at predetermined time intervals. This provides at least the advantage that less energy is consumed by the first sensor. In one embodiment, measuring the parameter indicative of road quality may be performed upon request from a user or from a control system. In one embodiment, measuring the parameter indicative of road quality may be performed when a predetermined criterion is fulfilled.

[0012] In one embodiment, the position determination may be performed each time a road quality measurement is performed. In one embodiment, the position determination may be performed more often than the road quality measurement is performed. In one embodiment, the position determination may be performed less often than the road quality measurement is performed. In one embodiment, the position determination may be performed when a predetermined number of road quality measurements are performed. In one embodiment, the road quality measurement may be performed when the position has been determined a predetermined number of times.

[0013] In one embodiment, determining the position of the first moving object may comprise: determining a movement path of the first moving object by recording movements of the first moving object; and comparing the determined movement path with possible movement paths for the first moving object in the underground environment.

[0014] High precision positioning systems in underground environments often rely on the moving object being visible to an access point of an underground communications network, for example through signal communication between the moving object and the access point. However, underground environments are unpredictable, ever-changing environments where both mountain walls, falling rock or large machines may come in the way for positioning signals. Therefore, positioning of the moving object by determining a movement path and comparing it to possible movement paths is a more robust method to position the moving object. This is at least because recording movements of the moving object does not rely on connection to an access point. If connection to a communications network is unavailable, the recorded movements may be stored locally, and the comparison may be performed when connection is reinstated. Furthermore, comparing the determined movement path with possible movement paths does not rely on connection to an access point either, as the possible movement paths may be stored locally in the mining vehicle, and the comparison may thus be performed and stored locally. In this way, no position information is lost even when connection to an underground communications network is unavailable. As such, not only the current position and the associated parameter indicative of road quality may be communicated to the communications network when connection is available, but also positions and associated parameter measurements during the time connection was unavailable.

[0015] In one embodiment, comparing the determined movement path with possible movement paths may comprise: comparing, through pattern matching, the determined movement path to known road segments of the underground environment, determining a road segment for which a matching error of the pattern matching is below a predetermined value, and determining that the position of the first moving object is on the determined road segment. In one embodiment, the known road segments may be provided as discretized patterns comprising nodes representing positions along the road segment, and wherein the pattern matching comprises: matching the nodes with the determined movement path of the first moving object.

[0016] Pattern matching is an efficient method to compare large sets of data. By additionally utilizing discretized patterns, the pattern matching may be performed even more efficiently as only the nodes are compared and not information relating to the entire road segment.

[0017] In one embodiment, the determined movement path may be a three- dimensional movement path. Thus, the determined movement path comprises information of if the vehicle is moving up or down in the underground environment.

[0018] In one embodiment, the parameter indicative of road quality may be a parameter relating to the evenness of the road. A more even or smooth road may be associated with a better road quality, and a less even road may be associated with a worse road quality.

[0019] In one embodiment, the parameter indicative of road quality may be a vibration parameter, and wherein measuring the parameter comprises: measuring vibrations in the first moving object.

[0020] Measuring vibrations in the first moving object may comprise measuring how much the first moving object vibrates, wherein a higher measured vibration may generally indicate a worse road quality than a lower measured vibration and/or measuring a change in vibration. Thus, it is possible to measure how much the road quality deteriorates or improves between different segments of the road in the underground environment.

[0021] In one embodiment, the parameter indicative of road quality may be a topographic parameter, and wherein measuring the parameter comprises: measuring height differences in the road, visually and/or by means of radiation.

[0022] Measuring a height difference may be to detect if gravel has piled up locally such that the road is less even. As such, a greater height difference between two selected points on the road may indicate a worse road quality than a lower height difference.

[0023] In one embodiment, the parameter indicative of road quality may be a gyroscopic parameter, and wherein measuring the parameter comprises: measuring a tilt of the first moving object.

[0024] Measuring how much a moving object is tilting may be an indication that gravel has piled up locally such that the road is less even. As such a greater tilt may indicate a worse road quality than a lesser tilt. Furthermore, a sudden or unexpected tilt may indicate a worse road quality than a less sudden or an expected tilt.

[0025] In one embodiment, the method according to first aspect may comprise measuring, by a second sensor provided on a second moving object, a parameter indicative of road quality, determining a position of the second moving object at a time at which the measurement was performed, associating the measurement by the second sensor to the determined position of the second moving object, when the determined position of the first moving object and the determined position of the second moving object matches: comparing the measurements of the parameter indicative of road quality, and determining a change in road quality based on the comparison.

[0026] By comparing information from several measurements, a mapping of the potential deterioration of the road quality may be obtained. As such, it is possible to know for example how fast the quality changes, what effects the road quality to change, and when will maintenance be required.

[0027] In one embodiment, the first sensor and the second sensor may be the same sensor, and the first moving object and the second moving object may be the same moving object.

[0028] When the same moving object travels a road segment several times, it may measure the road quality each time and the measurements may be compared to detect a change in road quality. [0029] In one embodiment, the first and second sensor may be different sensors, and the respective first and second moving object may be different moving objects.

[0030] By allowing more than one object in the underground environment to measure the road quality, more data may be generated leading to more reliable results. Furthermore, the first and second sensor may measure the road quality in different ways, that is measuring different parameters indicative of road quality, thus increasing reliability further.

[0031] In a second aspect of the disclosure, there is provided a monitoring system for monitoring road quality in an underground environment, wherein the underground environment comprises infrastructure for positioning of moving objects, the monitoring system comprising: a first sensor, arranged to be provided on a first moving object, for measuring a parameter indicative of road quality, processing circuitry, and a memory, wherein the monitoring system is operative for: measuring, by the first sensor, a parameter indicative of road quality, determining a position of the first moving object at a time at which the measurement was performed, associating the measurement of the parameter indicative of road quality to the determined position.

[0032] In one embodiment, the first sensor may be provided on an outside surface of the first moving object. In one embodiment, the first sensor may be provided on the chassis of the first moving object. In one embodiment, the first sensor may be integrated in a component of the first moving object. In one embodiment, the first sensor may be provided in another position on the first moving object.

[0033] In one embodiment, there may be provided a means for recording movements of the first moving object arranged to be provided on the first moving object, and wherein the monitoring system is further operative for: determining a movement path of the first moving object by recording movements of the first moving object; and comparing the determined movement path with possible movement paths for the first moving object in the underground environment. [0034] In one embodiment, the means for recording movements of the first moving object may be capable of recording movement in three dimensions.

[0035] In one embodiment, the first sensor may be a vibration sensor for measuring vibrations in the first moving object. Vibrations may for example be measures by an accelerometer, a piezoelectric sensor, a piezoelectric accelerometer, an integrated electronic piezoelectric accelerometer, a mems- accelerometer, or similar.

[0036] In one embodiment, the first sensor may be a topographic sensor for measuring height differences in the road visually and/or by means of radiation. Height differences may for example be measures by a camera, a radar, a lidar, a laser scanner or similar.

[0037] In one embodiment, the first sensor may be a gyroscopic sensor for measuring a tilt of the first moving object.

[0038] In one embodiment, there may be provided at least one additional sensor for measuring a parameter indicative of road quality, arranged to be provided on the first moving object.

[0039] In one embodiment, there may be provided at least one additional sensor for measuring a parameter indicative of road quality, arranged to be provided on a respective additional moving object of the underground environment.

[0040] In one embodiment, the at least one additional sensor may be for measuring the same parameter indicative of road quality as the first sensor.

[0041] In one embodiment, the at least one additional sensor may be for measuring another parameter indicative of road quality than the first sensor.

[0042] In one embodiment, the processing circuitry and memory may be comprised in a handheld unit, such as a consumer tablet or smartphone device. In one embodiment, the processing circuitry and memory may be comprised in a moving object of the underground environment, such as a mining machine. In one embodiment, the processing circuitry and memory may be comprised in a remote control system.

[0043] In a third aspect of the disclosure, there is provided a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to the first aspect.

[0044] In a fourth aspect of the disclosure, there is provided a computer- readable medium comprising instructions which, when executed by a computer, cause a computer to carry out the method according to the first aspect.

Brief description of drawings

[0045] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 displays a vehicle in an underground environment.

Fig. 2 displays two vehicles in an underground environment.

Fig. 3 displays a monitoring system.

Fig. 4 displays a method for monitoring road quality.

Fig. 5 displays a method for determining a position of a moving object.

Description of embodiments

[0046] In the following, a detailed description of a method and a system for monitoring road quality is provided. In the figures, like reference numerals designate identical or corresponding elements throughout the several figures. It will be appreciated that these figures are for illustration only and do not in any way restrict the scope of the present disclosure.

[0047] With reference to Fig. 1 there is shown a first moving object 100 in an underground environment II, such as a mining system, in relation to which the method 500 according to the disclosure may be executed. The first moving object 100 is generally a vehicle in the underground environment II. An exemplary first moving object 100 is displayed in Fig. 1 in the form of a mining truck. A mining truck is generally arranged for transporting blasted rock. To this end, the mining truck comprises a loading space 110 where blasted rock may be loaded. The loading space 110 may be lifted and tilted, by means of an unloading system 120, when blasted rock is to be emptied from the loading space 110. The mining truck may be driven by an electrical driving system, a combustion driving system or another type of driving system. The mining truck may be operated by an operator sitting inside the mining truck, operated by a remote operator or autonomously operated. The mining truck may furthermore be connected to a communications network 200 of the underground environment II comprising access points 210 for sending and receiving signals to objects in the underground environment II. The mining truck is arranged to transport blasted rock from a blasting site, through the underground environment II and out from the underground environment II. As such, the mining truck is adapted for traveling long distances along the many roads in the underground environment II.

[0048] In Fig. 1 there is furthermore shown a first sensor 410 of a monitoring system 400 for monitoring road quality according to the disclosure, the monitoring system 400 is described below with reference to Fig. 3. The first sensor 410 in Fig. 1 is arranged on the first moving object 100. The first sensor 410 is arranged to measure a parameter indicative of road quality. Because the first sensor 410 is arranged on the first moving object 100, the first sensor 410 may measure the road quality when the mining vehicle travels through the underground environment II, and furthermore at the position where the first moving object 100 is located. This makes is possible to collect large amounts of data, and furthermore to collect current data describing the present state of the roads in the underground environment II.

[0049] In Fig. 1 the first sensor 410 is arranged on an outside surface of the first moving object 100. The first sensor 410 in Fig. 1 is arranged close to a wheel of the first moving object 100, however other positions of the first sensor 410 are possible. The position may for example depend on what type of vehicle the first sensor 410 is arranged on. The position may furthermore depend on what type of sensor the first sensor is, that is, what parameter indicative of road quality it is arranged to measure and how that parameter is measured.

[0050] With reference to Fig. 2 there is displayed the first moving object 100 and a second moving object 300. The second moving object 300 is exemplified as a loader. The loader is arranged to load blasted rock into the mining truck at the blasting site. It will be understood that the exemplary vehicles are not limiting to the scope of the disclosure, and that other moving objects are possible.

[0051 ] The monitoring system 400 further comprises a second sensor 411 arranged on the second moving object 300. By providing both a first sensor 410 and second sensor 411 arranged on a respective moving object, the road quality may be measured at a larger number of positions in the underground environment II. Furthermore, data relating to the road quality may be collected at the same position by a larger number of sensors. Thus, a more robust estimation of the change of the road quality may be provided. The second sensor may also be arranged on the first moving object. In this case, the second sensor may measure the same parameter as the first sensor to give a more robust measurement, or another parameter indicative of the road quality, to additionally provide a more nuanced measurement.

[0052] With reference to Fig. 3 there is schematically displayed the monitoring system 400 according to the disclosure. Dashed lines display optional features of the monitoring system 400.

[0053] The monitoring system 400 generally comprises the first sensor 410, processing circuitry 420 and a memory 430. The processing circuitry 420, and memory 430, are arranged to communicate with the first sensor 410 to a obtain at least one measurement performed by the first sensor 410.

[0054] The monitoring system 400 further comprises, and is arranged to communicate with, a positioning system 440 for the first moving object 100 comprising means 441 for recording movements of the first moving object 100. The means 441 may comprise a gyroscope, an accelerometer and/or other devices suitable for determining how the first moving object 100 moves. The processing circuitry 420, and memory 430, are arranged to obtain at least one position from the positioning system 440. The method 500 for positioning will be described below with reference to Fig. 5.

[0055] The monitoring system 400 is furthermore arranged to associate the at least one measurement obtained from the first sensor 410 (and/or the second sensor 411 and/or additional sensors) to the at least one position obtained from the positioning system 440.

[0056] The memory 430 comprises a computer program 450 comprising instructions which, when the program is executed by a computer, cause the computer to carry out a method 500 for monitoring road quality according to the disclosure and a computer-readable medium comprising instructions which, when executed by the computer, cause a computer to carry out the method 500.

[0057] With reference to Fig. 4 there is displayed a method 500 for monitoring road quality in an underground environment II. The method 500 is arranged to be performed by the monitoring system 400 according to the disclosure.

[0058] The method 500 generally comprises the steps of: measuring 510 a parameter indicative of road quality, determining 520 a position of the first moving object 100 at a time at which the measurement was performed, and associating 530 the measurement of the parameter indicative of road quality to the determined position.

[0059] The first sensor 410 arranged on the first moving object 100 is arranged to measure 510 the parameter indicative of road quality. The measurement is recorded together in the monitoring system 400 together with a time stamp indicating a time at which the measurement was performed. The monitoring system 400 obtains a position of the first moving object 100 from the positioning system 440. The measurement is associated with the determined position such that it is known where in the underground environment II the measurement was performed. [0060] The second sensor 411 arranged on the second moving object 300 is furthermore arranged to measure the parameter indicative of road quality. The method 500 furthers comprises obtaining the measurement from the second sensor 411 , which in turn may be associated with a second position determination. The method 500 may thus further comprise determining that the position associated with the measurement by the first sensor matches the position associated with the measurement by the second sensor. Matching positions may be understood as being within a predetermined distance of each other. Matching positions may be understood as being on the same road segment. Matching positions may be understood as being in the same part of the underground environment II.

[0061 ] When the position associated with the measurement by the first sensor matches the position associated with the second measurement, measurements may be compared to determine if there has been a change in road quality on said position.

[0062] With reference to Fig. 5, the method 500 may further comprise determining 520 the position of the first moving object 100 in a manner which does not rely on communication with access points of the underground communications network 200.

[0063] The method 500 may comprise determining 521 a movement path of the first moving object 100. The movement path may be determined by recording movements of the first moving object 100 wherein recorded movements, together with information such as speed and traveled distance retrievable from a control system of the first moving object 100, can be utilized to determine a movement path of the first moving object 100. Said movements may be recorded by performing measurements with a gyroscope and/or accelerometer to record how the first moving object 100 turns left and right and travels uphill and downhill, measuring or obtaining speed and acceleration of the first moving object 100, measuring or obtaining a traveled distance of the first moving object 100. [0064] The movement path may be compared 522 to an existing map data structure representing the underground environment II comprising representations of possible movement paths of the first moving object 100. The comparing 522 may for example be carried out through pattern matching. Since travel routes are spatially restricted in an underground environment II, possible movement paths for an object traveling therein are often clearly defined, making the herein disclosed positioning method 500 possible.

[0065] Determining 520 the position of the first moving object 100 subsequently comprises determining 523 that a matching error of the pattern matching between the determined movement path and a possible movement path is below a predetermined threshold. When it is determined 523 that the matching error is below the threshold, it is determined 524 that the first moving object 100 is located on that road segment for which the matching error was below the predetermined threshold. The map data structure, as well as the determined movement path of the first moving object 100, may be in 2D or 3D.

[0066] The map data structure may be stored in the memory 430 of the monitoring system 400. It may also be stored in a remote system, in which case the determined movement path is stored in the memory 430 until communication is established with the remote system via the underground communications network 200, wherein the map data structure is obtained, and the comparison 522 can be made.

[0067] All or parts of the above method 500 steps may be performed without communication with an access point of an underground communications network 200.

[0068] Preferred embodiments of a method and a system for monitoring road quality in an underground environment have been disclosed above. However, a person skilled in the art realizes that this can be varied within the scope of the appended claims without departing from the inventive idea. [0069] All the described alternative embodiments above or parts of an embodiment can be freely combined or employed separately from each other without departing from the inventive idea as long as the combination is not contradictory.