TECHNICAL FIELD

The present disclosure relates to autonomous driving of mining machines, and, more specifically, to a computer-implemented method for autonomous routing of an underground mining machine to an un-mapped location, e.g., draw point, in an un-mapped underground environment. The disclosure also relates to an arrangement that implements the method, as well as to an underground mining machine comprising such an arrangement.

BACKGROUND

In the fields of mining and tunnelling, for example, there is an ongoing automation process, improving e.g., efficiency, productivity, and safety. Examples of changes/improvements that are carried out to an increasing extent is the automation of various repetitive processes occurring in mining and tunnelling.

It is, for example, often desirable that at least part of the mining machines that are used in mining/tunnelling can be driven in a fully autonomous mode, i.e., without an operator being required to control the mining machines during all instances of machine operation.

One example of mining machines where automated operation oftentimes is beneficial are so- called LHD (loading, hauling, and dumping) machines. These mining machines represent transport vehicles that may be used to remove broken rock, haul it to a particular place where the broken rock is dumped, and to return to the initial (start) location to pick up a new load. Thus, these vehicles often perform the same travel repeatedly, which makes the travel between load and dump locations well suited for automation. There are also various other situations where automation may prove beneficial.

To allow autonomous driving, it must be ensured that the vehicle is aware of its location in the environment in which it is traveling. Autonomous operation underground requires a representation of the surroundings, such as a map representation, that the vehicle can use for positioning and thereby be able to navigate from one location to another. Navigation rely highly on the representation of the vehicle environment. However, in some aspects of underground operations, such map representations may not be accessible. Forexample, when seeking to extract different types of ore from an ore pass, such as a sublevel cave or mine passage being successively developed during an excavation process, routing of the mining machine is usually unsupported by such a map representation. Consequently, there is a need for a different type of path generation, supporting tramming between an un-mapped location, e.g., at a draw point, and an ore pass.

SUMMARY

It is therefore an object of the present disclosure to provide a method, an arrangement, and a mining machine that seeks to mitigate, alleviate, or eliminate all or at least some of the above-discussed drawbacks of presently known solutions.

This and other objects are achieved by means of a computer-implemented method, an arrangement, and a mining machine as defined in the appended claims. The term exemplary is in the present context to be understood as serving as an instance, example or illustration.

According to a first aspect of the present disclosure, a computer-implemented method for routing of a mining machine in an underground environment is provided. The mining machine is configured for movement between a mapped location and an un-mapped location in the underground environment. The method comprises the step of determining directional data along wall-portions between the mapped location and the un-mapped location, wherein the directional data is determined for a mining machine reference point, and wherein the directional data is based on a representation of respective wall portions obtained during autonomous movement of the mining machine. The method further comprises the steps of routing the mining machine between the mapped location and the un-mapped location based on the determined directional data and determining a travelled distance between the mapped location and the un-mapped location.

Thus, a method is presented that enables safe and secure mining machine routing within a portion of the mine for which a map representation is unavailable, and in which the environment may be constantly changing due to the work performed by the mining machine. In some examples, routing of the underground mining machine along a return path from the un-mapped location to the mapped location is constrained by the determined travelled distance.

The constraining of the return route to the determined travelled distance, shortens the time of relocating the machine to the mapped location where state of the art routing may take place.

In some examples, the return path is generated based on directional data determined during autonomous movement from the mapped location to the un-mapped location. Thus, a return path may be calculated from directional data retrieved when moving in a direction of the unmapped location, e.g., draw point.

In some examples, determining of directional data along wall-portions from the mapped location to the un-mapped location comprises repeatedly obtaining a plurality of side measures to a wall portion on a left-hand and/or right-hand side of the mining machine, wherein the side measures are obtained by one or more sensors carried by the mining machine and determining a linear representation of the wall portion based on the plurality of side measures. The directional data is determined for a predetermined reference point of the mining machine and is based on the linear representation of the wall portion. The determined directional data is used to move the mining machine to a wall portion closer to the un-mapped location, i.e., during routing the mining machine from the mapped location to the un-mapped location. The directional data may comprise, for each wall portion, a vector originating from a predefined reference point on the mining machine, e.g., a rotational centrum of a front frame of the machine.

Thus, directional data is determined during movement of the mining machine from the mapped location to the un-mapped location. Correspondingly, directional data may be determined during the return travel from the un-mapped location to the mapped location. Determining of directional data enables improved accuracy during movement of the mining machine, but also improved accuracy in targeting the un-mapped location, e.g., draw-point. In some examples, the obtaining of a plurality of side measures comprises obtaining a predetermined number of sensor measurements, e.g., from one or more LIDAR sensors and/or radar sensors, along said wall portion and directional data may be determined by obtaining the plurality of side measures along a plurality of adjoining wall portions from the mapped location to the un-mapped location.

Thus, side measures may be obtained with high accuracy all along the adjoining wall portions and are used to maintain a preconfigured distance between the mining machine and said wall portion during controlled movement of said mining machine between the mapped location and the un-mapped location, e.g., draw-point.

According to a second aspect of the present disclosure, there is provided a computer program product comprising a non-transitory computer readable medium having thereon a computer program comprising program instructions loadable into processing circuitry and configured to cause execution of the method according to the first aspect when the computer program is run by the processing circuitry.

According to a third aspect of the present disclosure, a routing arrangement is provided. The routing arrangement is configured to be comprised in a mining machine configured for movement between a mapped location and an un-mapped location in the underground environment. The routing arrangement comprises processing circuitry configured to determine directional data along wall-portions between the mapped location and the unmapped location, wherein the directional data is determined for a mining machine reference point, and wherein the directional data is based on a representation of respective wall portions obtained during autonomous movement of the mining machine. The processing circuitry is further configured to determine a travelled distance between the mapped location and the un-mapped location; and to routing the mining machine between the mapped location and the un-mapped location based on the determined directional data.

According to a fourth aspect of the present disclosure, a mining machine is provided. The mining machine is configured for autonomous movement between a mapped location and an un-mapped location in the underground environment. The mining machine comprises the routing arrangement according to the third aspect.

The above reflected advantages and others are provided also by the computer program code, the routing arrangement, and the mining machine.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particular description of the example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the example embodiments.

Figure 1 illustrates a mining machine comprising a routing arrangement according to the present disclosure

Figure 2 discloses the mining machine in the context of an underground environment

Figure 3 provides a flowchart representation of example method steps performed by the routing arrangement of the mining machine;

Figure 4 discloses an example block diagram of a routing arrangement.

DETAILED DESCRIPTION

Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. The apparatus and method disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

The terminology used herein is for the purpose of describing aspects of the disclosure only and is not intended to limit the invention. It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of certain features, steps, or components, but does not preclude the presence or addition of one or more other features, steps, components, or groups thereof. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Embodiments of the present disclosure will be described and exemplified more fully hereinafter with reference to the accompanying drawings. The solutions disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the embodiments set forth herein.

In some implementations and according to some aspects of the disclosure, the functions or steps noted in the blocks can occur out of the order noted in the operational illustrations. For example, two blocks shown in succession can in fact be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality/acts involved. Also, the functions or steps noted in the blocks can according to some aspects of the disclosure be executed continuously in a loop.

It will be appreciated that when the present disclosure is described in terms of a method, it may also be embodied in one or more processors and one or more memories coupled to the one or more processors, wherein the one or more memories store one or more programs that perform the steps, services and functions disclosed herein when executed by the one or more processors.

In the following description of exemplary embodiments, the same reference numerals denote the same or similar components.

Figures 1 discloses an underground mining machine 10 from a side view. The underground mining machine 10 is configured for autonomous movement in an underground mining environment. The illustrated mining machine 10 is a loader/hauler comprising a vehicle body 11, a bucket 12, and a routing arrangement. It will be appreciated that the principles are equally applicable to other type of work machines configured to perform autonomous movement in an underground or tunnel environment. Thus, the present disclosure is not limited to a loader/hauler type of mining machine 10 as disclosed in Figure 1, the disclosure is equally applicable to other types of mining machines, such as dumpers, concrete spraying machines, drilling rigs and/or bolting rigs. The mining machine further comprises one or more range detection sensors. In some examples, the range detection sensors 14, 15 are laser range scanners configured to measure distances using laser beam technology in given directions and with given angles. The skilled person will appreciate that other types of range detections or distance measuring sensors would be equally applicable for the purpose of determining a distance between the mining machine and its surroundings. In some examples, the side measures are laser measurements obtained by one or more LIDAR sensors. In some examples, the side measures are radar measures obtained by one or more radar sensors. In some examples, a plurality of different type of sensors may be used, e.g., using a combination of LIDAR and radar sensors to obtain the range detection data. In the disclosed example, the mining machine comprises a front range detection sensor 14 and a rear range detection sensor 15, that are configured to determine a distance from the respective sensor to path barriers present along a path travelled by the mining machine during tramming. However, the present disclosure is in no way limited to the disclosed placing of the range detection sensors. Any type of sensor mounting and sensor type that supports distance measuring/range detection to surrounding walls and obstacles are within the scope of the present disclosure.

The range detection sensors are used to measure distances to an object/barrier, e.g., a rock wall, a rock, or any other path barrier along the path travelled by the mining machine during tramming. The front range detection sensor 14, e.g., laser range scanner, may be used to obtain range readings, e.g., from a laser scan over a range detection field or segment. In some examples, the laser range scanner will provide range readings for each whole degree ± 90 degrees from the respective longitudinal direction during a scan. Thus, each respective laser range scanner may measure the distance at 181 respective measurement points. As will be understood, it is possible to use laser range scanners which measure distance, obtain range readings, at a significantly higher resolution or at a significantly lower resolution. It is also possible to use laser range scanners which obtain range readings in a significantly wider direction, as well as those which measure distance in a narrower direction. It is also possible to use one or more single omnidirectional range detection sensors to determine distance in any travelling direction of the vehicle or a rotating range detection sensor. The one or more range detection sensors 14,15 are mounted on the mining machine. When mounting the range detection sensors on a machine comprising a bucket or scoop, one range detection sensor may be arranged on top of the mining machine, e.g., at a position maintaining a line of sight for the range detection sensor from the vehicle to the surrounding environment also when the bucket is in a lowered position, in a partly lifted position and/or in a lifted position. Further range detection sensors may be provided at a lower part of the mining machine so that obstacles on the ground may be detected at times when the bucket is in a partly lifted position and/or in a lifted position, i.e., not obscuring the line of sight for range detection sensor mounted on a lower part of the mining machine. Consequently, the mounting of range detection sensors as visualized in Figure 1 is only for general understanding and the below proposed method will be equally applicable regardless of the where the range detection sensor is mounted on the mining machine.

Turning to Figure 2, the mining machine 10 is disclosed in the context of an underground environment. The hereinafter disclosed method, routing arrangement and mining machine are adapted for used in an underground environment comprising a first environment and a second environment as indicated in Figure 2. The first environment is associated with a predetermined representation, e.g., a rendered map. The predetermined representation of the first environment comprises a plurality of mapped locations A enabling locational awareness for the machine throughout the first environment. Autonomous movement of the mining machine in the first environment may be based on a pre-recorded route wherein the mining machine autonomously moves between a plurality of mapped and identifiable locations in the first environment. The underground mining environment also comprises a second unrecorded environment, i.e., an environment comprising one or more un-mapped locations B. When performing an ore extraction operation, the mining machine will move from the first environment into the second environment and travel to an un-mapped location, e.g., draw-point, where loading of ore may be performed. When moving into the second environment, the mining machine no longer has access to a pre-obtained representation of the travel environment and the route for the autonomous routing of the machine needs to be determined whilst moving the machine. The one or more range detection sensors 14,15 are configured to enable determination of a distance to a closest object/barrier in any selected direction, e.g., a distance to a wall-portion, when entering the second environment and moving in a direction of the un-mapped location. The distance travelled in the second environment will usually be a short distance up to the unmapped location. Since the machine is to initiate a loading process at the un-mapped location, e.g., draw point, the machine speed will be reduced compared to the tramming speed in the first environment. Following an ore loading process, the mining machine returns from the second environment back into the first environment, wherein the mining machine may continue an autonomous driving with locational awareness supported by the predetermined representation of the environment. There is a need to provide a solution wherein a mining machine may maneuver in an autonomous mode back and forth between the above disclosed first and second environment.

The present disclosure is not limited to a loader/hauler type of mining machine 10 as disclosed in Figure 1, nor is it limited to a scenario where the un-mapped location is point for removal of broken rock, e.g., draw point. The disclosure is equally applicable to other types of mining machines, such as dumpers, concrete spraying machines, drilling rigs and/or bolting rigs. The disclosure is also equally applicable to scenarios where the un-mapped location represents any un-mapped rock drilling site or other work site for which a pre-recording or map representation is unavailable.

Turning back to a background understanding of the ore extraction/loading process from an un-mapped location, e.g., draw point, an implementation of fully autonomous loading requires use of a local navigation method for entering and exiting the un-mapped location, e.g., the pile of material at the draw point. The local navigation relates to movement of the mining machine between a mapped location in the first environment to the un-mapped location in an essentially unknown second environment. In some instances, the nature of the mining process, e.g., block cave mining, is such that loading takes place at a un-mapped location, e.g., draw-point, at an end of a narrow passage to the draw-point, essentially resulting in a single-direction draw-point approach. In other instances, the entry passage to an un-mapped location, e.g., draw-point may allow multi-directional draw-point approaches, and this may of course also be possible when a narrow passage leads into a wider extraction space.

Turning to Figure 3, aspects of a computer-implemented method for routing a mining machine, in an underground environment is disclosed. The mining machine, i.e., an underground mining machine, may be routed back and forth between first and second portions of the underground environment, i.e., between a first environment and a second environment. Hence, the mining machine is configured for movement between a mapped location, e.g., a mapped location in the first environment, and an un-mapped location, e.g., an un-mapped location in the second environment.

The method comprises an optional step of positioning S310 the mining machine in a direction of the un-mapped location B, when starting a movement of the mining machine at the mapped location A.

In its most general form, the proposed method may be initiated at the mapped location A as illustrated in Figure 2. The mapped location represents a hand-over position between the first environment and the second environment, i.e., a hand-over position from conventional autonomous routing according to a map representation.

The method comprises the step of determining S320 directional data along wall-portions between the mapped location and the un-mapped location, and wherein the directional data is based on a representation of respective wall portions obtained during autonomous movement of the mining machine. The directional data may be obtained from sensor data, e.g., sensor data from one or more range detection sensor, during movement of the mining machine along wall-portions. Thus, the mining machine is configured to perform a wallfollowing movement, whereby the mining machine is routed along consecutive directional approximations of respective wall-portions and discontinuing the wall-following movement when detecting reach of an un-mapped location, e.g., draw point.

The directional data is determined for a mining machine reference point. In some examples, the determining S320 of directional data comprises to obtain S320a a plurality of side measures to a wall portion on a left-hand and/or right-hand side of the mining machine, wherein the side measures are obtained by one or more sensors carried by the mining machine and to determine S320b a linear representation of the wall portion based on the plurality of side measures. In some examples, the step of obtaining S320a a plurality of side measures comprises obtaining a predetermined number of sensor measurements along said wall portion. In some examples, the plurality of side measures are obtained along a plurality of adjoining wall portions from the mapped location A to the un-mapped location B. In other instances, the plurality of side measures may be obtained along wall portions located on opposite sides of the mining machine, whereby measurements are obtained along a wall portion on a first side if a consistent set of side measures are obtained. When detecting one or more deviating side measures, wall-following may be continued on the other side of the machine. Thus, the plurality of side measures may be interchangeably obtained from wall portions located on both sides of the mining machine when appropriate.

Based on the linear representation of the wall portion, directional data for a predetermined reference point of the mining machine is determined S320c. in some examples, the directional data comprises, for each wall portion, a vector originating at the reference point of the mining machine. The reference point may be a center point of a front frame of the machine, e.g., a rotational center point.

The mining machine is then moved S320d to a wall portion closer to the un-mapped location (B), wherein the movement is controlled to be in alignment with the determined directional data. The determining of directional data may then be repeated at the next position of the mining machine. The repeated determining S320 of directional data may be performed in response to receiving additional sensor data from the one or more sensors. In some examples, the step of obtaining S320a a plurality of side measures comprises obtaining a predetermined number of sensor measurements along said wall portion, e.g., along a plurality of adjoining wall portions from the mapped location A to the un-mapped location B.

In some examples directional data is represented by an approach vector, the vector reflecting a position and direction of the mining machine, e.g., the mining machine reference point. Assuming that the un-mapped location is a narrow draw point (loading point) in a block cave extraction scenario, a single approach vector may form an adequate representation of directional data. When the draw point (loading point) is narrow, this will may only allow for one approach direction. Based on the representation of respective wall portions obtained during movement of the machine, e.g., range detection data such as laser data acquired from the sensors on the machine, the approach vector may be determined to correspond to a direction of said wall portions. In some examples, the wall portions will be located on a righthand side or a left-hand side of the mining machine depending on the location of the draw point.

In some instances, e.g., assuming that the un-mapped location is a wider draw point (loading point) in a block cave extraction scenario, variations in the directional data are expected and beneficial. This is particularly beneficial, when the un-mapped location represents a wider area that can be accessed from multiple, slightly varying approach directions. In such instances, movement of the mining machine may take place allowing greater variations in the determining of directional data. The directional data may consist of a vector with a static or dynamic offset compared to the representation of the wall, thus allowing the machine to change the distance and direction compared to the wall while moving along the wall. Consequently, autonomous movement of the mining machine may take place, allowing variations in the approach direction toward the un-mapped location.

The method further comprises routing S330 of the mining machine between the mapped location and the un-mapped location based on the determined directional data. The mining machine is configured for autonomous movement at a routing speed, wherein the routing speed may vary depending on the capabilities for real-time processing of the obtained S120a side measures. As previously explained, directional data is determined by e.g., obtaining several laser measurements (laser points) along the side of the machine, and to approximate a representation of the wall, e.g., a linear representation. The number of laser points to be used can be set as a parameter. The representation is then transformed to directional data, e.g., to a vector originating from a reference point, such as a rotational center, of the front frame of the machine. The transformation may depend on an allowable distance between the wall and the mining machine. As mentioned, the directional data may consist of a vector with a static or dynamic offset compared to the representation of the wall, thus allowing the machine to change the distance and direction compared to the wall while moving along the wall. The directional data, e.g., vector, may be used as input to a path tracking algorithm, e.g., the path tracking algorithm used for running routes in the first environment, i.e., in an environment comprising mapped locations. As the machine moves along the wall, new side measures are obtained to update the vector continuously, thus allowing the machine to follow the wall through bends. The machine continues to move like this until it reaches the unmapped location, e.g., a draw point of an ore pile.

In some examples, the distance measurements obtained from the one or more range detection sensors of the mining machine may be used to stop movement of the mining machine when reaching the un-mapped location, e.g., draw-point. General obstacle detection sensors, e.g., sensors capable of reacting to an obstacle but without determining the distance to the obstacle, may also be used to impact movement of the mining machine when reaching the un-mapped location. When detecting reach of the unmapped location, e.g., the range detection sensor detecting a predetermined distance to an obstacle in the travelling direction, a travelled distance is determined S340. The travelled distance represents the distance between the mapped location A and the un-mapped location B.

Thus, a method is presented that enables safe and secure mining machine routing within a portion of the mine for which a map representation is unavailable, and in which the environment may be constantly changing due to the work performed by the mining machine.

The present disclosure also comprises the optional step of performing S350 an autonomously executed mining operation at the un-mapped location, e.g., by performing a loading operation when reaching the un-mapped location B. In some examples, the un-mapped location is a draw point of a rock pile, and optionally a rock column of rock cave mining.

The un-mapped location may also be drill face for production drilling. Thus, other type of operations may also be performed when reaching un-mapped location, e.g., performing a drill operation with a mining machine configured for drilling. Such operation may be performed as an autonomous drill operation or as a remotely controlled drill operation.

In some examples, routing of the underground mining machine along a return path from the un-mapped location to the mapped location is constrained by the determined travelled distance. The constraining of the return route to the determined travelled distance, shortens the time of relocating the machine to the mapped location, i.e., to the hand-over position, from which conventional routing may take place.

After the operation at the un-mapped location, e.g., loading at a draw-point is completed, the saved distance is used to travel backwards the same distance as the machine travelled into the pile. Returning from the un-mapped location, the mining machine will resume a wallfollowing movement until having travelled a distance toward the mapped location that corresponds to the distance travelled from the mapped location to the un-mapped location. When the travelled distance back from the un-mapped location to the mapped location corresponds to a determined travelled distance moving toward the un-mapped location, autonomous routing using a map representation is resumed.

In some examples, the mining machine may be routed S360 along a return path from the unmapped location B to the mapped location A based on directional data determined during autonomous movement from the mapped location A to the un-mapped location B. Thus, the return path may be generated using the wall-following approach taken when performing the movement toward the un-mapped location, or by computing a return path using the directional data and associated travel distances obtained during the routing to the un-mapped location.

Turning to Figure 4, a schematic block diagram illustrating a routing arrangement 40, e.g., the routing arrangement 11 as comprised in the mining machine 10 of Figure 1. The routing arrangement 40 is configured to perform the above disclosed method. In the context of the present disclosure, the routing arrangement is capable of localization of the mining machine in the first environment and/or of obstacle detection, e.g., to support a collision avoidance functionality implemented in the mining machine. The routing arrangement comprises processing circuitry 41 configured to determine a route for routing of the mining machine between a mapped location and an un-mapped location.

The processing circuitry may comprise a processor 41a and a memory 41b. Figure 4 further illustrates an example computer program product 42 having thereon a computer program comprising instructions. The computer program product comprises a computer readable medium such as, for example a universal serial bus USB memory, a plug-in card, an embedded drive, or a read only memory ROM. The computer readable medium stores a computer program comprising program instructions that are loadable into the processing circuitry 41, e.g., into the memory 41b. The program instructions may be executed by the processor 41a to perform the above disclosed method.

Thus, the computer program is loadable into data processing circuitry, e.g., into the processing circuitry 41 of Figure 4, and is configured to cause execution of embodiments for diagnosing range detection capability of the at least one range detection sensor.

The description of the example embodiments provided herein have been presented for purposes of illustration. The description is not intended to be exhaustive or to limit example embodiments to the precise form disclosed; modifications and variations are possible within the scope of the above teachings or may be acquired from practice of various alternatives to the provided embodiments. The examples discussed herein were chosen and described to explain the principles and the nature of various example embodiments and its practical application to enable one skilled in the art to utilize the example embodiments in various manners and with various modifications as are suited to the particular use contemplated. The features of the embodiments described herein may be combined in all possible combinations of source nodes, target nodes, corresponding methods, and computer program products. It should be appreciated that the example embodiments presented herein may be practiced in combination with each other.

The described embodiments and their equivalents may be realized in software or hardware or a combination thereof. The embodiments may be performed by general purpose circuitry. Examples of general-purpose circuitry include digital signal processors DSP, central processing units (CPU), co-processor units, field programmable gate arrays FPGA and other programmable hardware. Alternatively, or additionally, the embodiments may be performed by specialized circuitry, such as application specific integrated circuits ASIC. The general- purpose circuitry and/or the specialized circuitry may, for example, be associated with or comprised in an apparatus such as a wireless communication device or a network node. Embodiments may appear within an electronic apparatus comprising arrangements, circuitry, and/or logic according to any of the embodiments described herein. Alternatively, or additionally, an electronic apparatus may be configured to perform methods according to any of the embodiments described herein.

Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used.

Reference has been made herein to various embodiments. However, a person skilled in the art would recognize numerous variations to the described embodiments that would still fall within the scope of the claims.

For example, the method embodiments described herein discloses example methods through steps being performed in a certain order. However, it is recognized that these sequences of events may take place in another order without departing from the scope of the claims. Furthermore, some method steps may be performed in parallel even though they have been described as performed in sequence. Thus, the steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step.

In the same manner, it should be noted that in the description of embodiments, the partition of functional blocks into particular units is by no means intended as limiting. Contrarily, these partitions are merely examples. Functional blocks described herein as one unit may be split into two or more units. Furthermore, functional blocks described herein as being implemented as two or more units may be merged into fewer (e.g., a single) unit.

Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever suitable. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa.

In the drawings and specification, there have been disclosed exemplary aspects of the disclosure. However, many variations and modifications can be made to these aspects without substantially departing from the principles of the present disclosure. Thus, the disclosure should be regarded as illustrative rather than restrictive, and not as being limited to the aspects discussed above. Accordingly, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. Hence, the details of the described embodiments are merely examples brought forward for illustrative purposes, and all variations that fall within the scope of the claims are intended to be embraced therein.