TECHNICAL FIELD

The invention relates to a method for estimating work cycles of a working operation for a working machine comprising an implement. The invention also relates to a computer program, a computer readable medium, a control unit and a system.

The invention is applicable on working machines within the fields of industrial construction machines or construction equipment, in particular wheel loaders. Although the invention will be described with respect to a wheel loader, the invention is not restricted to this particular machine, but may also be used in other working machines such as articulated haulers, excavators, forwarders and backhoe loaders.

BACKGROUND

Working machines in the form of articulated haulers, wheel loaders, trucks, forwarders and dumpers are frequently used for loading and transporting of material loads at construction sites, in forestry and the like. A load-receiving container of a hauler or dump truck may for instance be loaded with unprocessed material, such as rock fragments, at a loading location, transport the material to a another location and dump the material (in)to a material processing device, such as into a buffering feeder of a crusher arranged to crush the rock fragments into smaller fragments.

Oftentimes the working machines repeat the same operation a number of times, and it may be desirable to perform work cycle analyses for the working machines. There are several reasons for performing such analyses of work cycles.

1 ) One reason is to provide driver support. By analysing the work cycles of a working machine, it may be possible to give recommendations to the driver based on his/her behaviour. For instance, warning signals or suggestions may be displayed in the cabin.

2) Another reason is for setting machine parameters. The machine parameters may be set based on such a work cycle analysis, for instance in order to reduce fuel consumption and/or obtain higher productivity.

3) A further reason is for providing statistics to back office. For instance, a fleet manager or the supplier of the working machines may use the analyses for determining how the operator has operated the machine, and may use the information for making decision on e.g. the need of driver training, the need of rebuilding/rearranging the working site, and/or for determining whether or not the working machine is driven in line with a service agreement based on a certain chosen application.

However, working machines may normally be used for performing several different operations. For instance, the working machine may be operated to change from performing a first working operation to a second working operation. Such a change may occur in the middle of a work cycle of the first working operation. In such case the last work cycle of the first working operation will not be detected as a work cycle. In some cases, this is not a big problem. For instance, as regards the above mentioned third reason (providing statistics to back office), one will get relatively reliable statistics if there is a large repetition of the same work cycle before changing to the next working operation. However, in cases when a working machine frequently changes between different working operations, i.e. in cases when there is a frequent change of work cycles, the statistics may become less reliable, since many of the work cycles will be incomplete and will therefore not be detected as work cycles, and will therefore not be properly included in the work cycle analysis. It would therefore be desirable to provide improved statistics with respect to work cycles of a working machine.

SUMMARY

An object of the invention is to provide a method, a computer program, a computer readable medium, a control unit and a system, which can be used for providing improved statistical analyses of work cycles of a working machine.

According to a first aspect of the invention, the object is achieved by a method for estimating work cycles of a working operation for a working machine comprising an implement, in accordance with claim 1. The method comprises:

- determining a starting location for an implement of the working machine;

- determining a destination location for the implement,

wherein a completed work cycle comprises the implement being moved from the starting location to the destination location and back to the starting location;

- determining an expected sequence of operating steps to be performed by the working machine for the work cycle to be completed after the implement has finalized the movement from the starting location to the destination location; - detecting the operating steps that the working machine performs after the implement has reached its destination location;

- comparing the detected operating steps with the expected sequence of operating steps, wherein, when the detected operating steps fail to follow said expected sequence of operating steps:

- determining that the working operation is finished and that a final work cycle has been interrupted; and

- using working machine data from the interrupted final work cycle in order to virtually completing the interrupted final work cycle into a virtually completed work cycle.

By the provision of a method which takes into account interrupted work cycles, and virtually completing them, a larger statistical base may be obtainable. Furthermore, by virtually completing the interrupted final work cycle, different working operations are more correctly separated from an analytical perspective. Thus, even when the working machine is controlled to frequently perform different working operations (and might therefore perform only a few work cycles per working operation) an improved statistical base may be obtained as the interrupted final work cycle will be taken into account.

It should be noted that (even though the virtual completion of the interrupted final work cycle may not make the statistics entirely correct) since the information on how many virtual completions that have been executed is readily obtainable, the relevance of the statistics may be estimated. For instance, if 10% of the data is used for virtual completion, the statistics is more relevant than if 90% of the data is used for virtual completion. In either case, a user may make an improved and more informed decision on how to use the statistics, compared to the information that would be available if the interrupted final work cycle would not be detected at all.

According to at least one exemplary embodiment, said step of using working machine data from the interrupted final work cycle comprises:

- using working machine data containing information on a part of a transport of the working machine from the finished working operation to a subsequent working operation, for virtually completing the interrupted final work cycle of the finished working operation.

This may be advantageous, since the readily obtainable working machine data may be used for virtually completing the interrupted final work cycle. For instance, sometimes a working machine is seemingly returning from the destination location towards the starting location, but instead of stopping at the starting location to start a new work cycle, the driver drives the working machine past the starting location and heads towards another location to perform a different working operation. In such cases, a part of the transport between the destination location and said other location may be used for virtually completing the interrupted final work cycle. Suitably, the working machine data representative of the transport up to the point at which the working machine is level with the starting location, will be used to virtually complete the work cycle (noting that the operating step of transporting from the destination location to said other location is not part of the expected operating steps). The working machine data representative for the remaining part of the transport may be defined as part of another working operation, or as just a transport between two working operations.

According to at least one exemplary embodiment, when the detected operating steps fail to follow said expected sequence of operating steps, the method further comprises:

- disregarding at least part of the detected operating steps,

wherein said step of using working machine data comprises:

extrapolating working machine data from the interrupted final work cycle in order to estimate virtual operating steps completing the interrupted final work cycle into a virtually completed work cycle.

Hereby, even though working machine data for the rest of the final work cycle is not available, working machine data acquired from previous work cycles may be used to extrapolate the interrupted final work cycle, which may therefore become virtually completed. Some exemplary embodiments of such extrapolation based on previous work cycles will be presented in the following.

According to at least one exemplary embodiment, the step of extrapolating working machine data comprises using working machine data generated in a previous work cycle of the working operation. This is a simple manner of extrapolating. One make copy and paste working machine data from a previous work cycle (i.e. the working machine data representative of the operating steps which are missing in the final work cycle). This may be particularly advantageous when the working machine is used in a simple working operation or is working within a small confined area, i.e. in cases when there is not expected to be great variation between the individual work cycles of a working operation. According to at least one exemplary embodiment, the step of extrapolating working machine data comprises calculating and using an average of the working machine data generated in several or all previous work cycles of the working operation. This may be advantageous when the working machine is used in a more versatile and/or complex working operation, or is working within a relatively large working area, i.e. when a substantial variation of working machine data may be expected from one work cycle to another within the same working operation.

According to at least one exemplary embodiment, the method step of disregarding at least part of the detected operating steps, comprises disregarding the first one of the detected operating steps that breaks the expected sequence of operating steps and any subsequent detected operating step. Hereby, only those of the actually detected operating steps that would form part of a true completed work cycle will be included in the virtually completed work cycle. The risk of detected operating steps which might skew the statistics are thus disregarded.

According to at least one exemplary embodiment, said act of determining an expected sequence of operating steps, comprises:

- detecting a first sequence of operating steps performed by the working machine when moving the implement from the starting location to the destination location,

- determining a second sequence of operating steps which are in a reversed order compared to at least a subset of the first operating steps, wherein said expected sequence is said second sequence. By basing the expected sequence on the detected first sequence a simple determination of the expected sequence of operating steps is obtainable.

According to at least one exemplary embodiment, said working machine remains in a parked position when the implement is moved between the starting location and the destination location. This is advantageous since some working operations do not require that the entire working machine moves from one place to another. For instance, an excavator or shovel may be parked and pick up a load from a pile into its bucket, and the excavator or shovel arm with the bucket may be rotated to a container or truck to discharge the load, without moving the wheel loader from its parked position.

According to at least one exemplary embodiment, each one of said operating steps is selected from the group consisting of: moving the implement within a defined working area,

moving the implement to a defined intermediate location on its way to the starting location or the destination location,

moving the implement in a defined direction,

moving the implement a defined distance or distance range,

changing movement direction of the implement,

loading or unloading the implement of the working machine,

any combination of the above listed actions.

Thus, advantageously, a number of different operating steps may be included in a work cycle analysis, thereby enabling the acquiring of appropriate statistical information.

According to at least one exemplary embodiment, said implement is moved between the starting location and the destination location by driving the working machine between the starting location and the destination location. This is advantageous as the method may also be implemented in embodiments in which the entire working machine is moved, not just a part of the working machine while being parked. An example of such a work cycle could be picking up load at a starting location, reversing the working machine, turning the working machine and driving forwardly to a destination location, unloading the load, reversing the working machine, turning the working machine and returning to the starting location.

According to at least one exemplary embodiment, the method comprises detecting a driving direction and a distance covered by the working machine when driving to the destination location, wherein an operating step in said expected sequence of operating steps comprises driving the working machine substantially the same distance but in a reverse direction to said driving direction. Hereby, a simple determination of the expected sequence is achievable, by basing the determination on the previously detected driving direction and covered distance.

According to at least one exemplary embodiment, each one of said operating steps is selected from the group consisting of:

moving, such as lifting, lowering, rotating and/or tilting, the implement of the working machine,

moving the implement within a defined working area,

moving the implement to a defined intermediate location on its way to the starting location or the destination location, moving the implement in a defined direction,

moving the implement a defined distance or distance range,

changing movement direction of the implement,

loading or unloading the implement of the working machine,

driving the working machine within a defined working area,

driving the working machine to a defined intermediate location on its way to the starting location or the destination location,

driving the working machine in a defined direction,

driving the working machine a defined distance or distance range,

changing movement direction of the working machine,

loading or unloading the implement of the working machine,

rotating an upper structure of the working machine through a defined swing angle, any combination of the above listed actions.

Thus, advantageously, a number of different operating steps may be included in a work cycle analysis, thereby enabling the acquiring of appropriate statistical information.

According to at least one exemplary embodiment, the method comprises defining a virtual geographic boundary for said working operation, for example by means of a positioning system, such as by means of a GPS or RFID system, or by defining a number of allowable rotations of a wheel axis from a certain location (such as the starting location, the destination location or an intermediate location), wherein said expected sequence of operating steps includes moving the implement without crossing said virtual geographic boundary. This is advantageous since this allows a certain flexibility. The working machine does not need to perform exactly the same motion (e.g. directions and distance) for each work cycle of a working operation. There may be certain tolerances as long as the implement, and suitably the working machine, remains within said virtual geographic boundary.

According to at least one exemplary embodiment, the work cycle is a load cycle. Hereby the most common, or one of the most common, types of work cycles is estimated by the exemplary embodiment. It should be understood that although load cycles are common, the invention is not limited to these. Thus, in other exemplary embodiments the work cycle may be a different cycle. For instance, in forestry, the work cycle may be a tree cutting and/or a tree loading cycle.

According to at least one exemplary embodiment, said starting location is one of - a first location, for loading an implement of a working machine with material, and

- a second location, for unloading material from the implement of the working machine, wherein said destination location is the other one of said first and second locations. This is advantageous, since the method may be implemented regardless if one considers the loading or the unloading of material as a starting point for the analysis.

According to at least one exemplary embodiment, the method comprises determining that the working machine has unloaded material from its implement, wherein said method step of comparing the detected operating steps with said expected sequence of operating steps comprises comparing a first driving direction and first distance driven by the working machine after unloading the material with a second driving direction and second distance driven by the working machine prior to unloading the material, wherein it is determined that the working operation is finished and that a final work cycle has been interrupted if:

- the direction reverse to the first driving direction is substantially different from the second driving direction, and/or

- the first driving distance is substantially different from the second driving distance.

Hereby, a simple determination is achievable, by basing the determination on a comparison of the driving direction and/or distance prior to and after unloading the material.

According to at least one exemplary embodiment, said working machine data comprises any one of or any combination of the following vehicle parameter values:

- number of rotations of one or more road wheel of the working machine,

- travel distance of the implement,

- travel distance of the working machine,

- steering angle,

- swing angle,

- movement direction of the implement

- driving direction of the working machine,

- pressure in one or more cylinders, such as lift and/or tilt cylinders, of a working machine,

- torque of an engine of the working machine,

- velocity of the working machine,

- time of travel of the working machine,

- energy consumption, such as fuel consumption and/or battery power consumption,

- weight of load handled during the work cycle,

- tire pressure, - tire temperature,

- wheel brake energy and/or power,

- engine speed,

- forces, such as acceleration forces, on one or more parts of the working machine.

By having a large number of potential parameters values, an improved work cycle estimation is obtainable.

According to at least one exemplary embodiment, the method comprises

- collecting the working machine data representing the virtually completed work cycle, and - collecting any additional data representing work cycles of said working operation which have been completed before the virtually completed work cycle.

Hereby, data representative of one or more actually completed work cycles as well as the virtually completed work cycle will be collected and available for analysis. This provides improved statistics for analysing how the working machine has been operated.

According to at least one exemplary embodiment, the method comprises, after determination that the working operation is finished:

- determining that the working machine is transported to a new starting location for a new working operation.

Hereby, different working operations and work cycles thereof may readily be distinguished from one another.

According to at least one exemplary embodiment, said implement is a tool for carrying a load, such as a bucket, shovel, forks, gripping tool, timber grapple, material arm or excavating tool. Thus, the invention may advantageously be carried out in connection with various different working machines and implements.

According to a second aspect of the invention, there is provided a computer program comprising program code means for performing the method steps of the method of the first aspect, including any embodiment thereof, when said program is run on a computer.

According to a third aspect of the invention, there is provided a computer readable medium carrying a computer program comprising program code means for performing the method steps of the method of the first aspect, including any embodiment thereof, when said program product is run on a computer. According to a fourth aspect of the invention, there is provided a control unit for estimating work cycles of a working operation for a working machine, the control unit being configured to perform the method steps of the method of the first aspect, including any embodiment thereof.

The control unit may include a microprocessor, microcontroller, programmable digital signal processor or another programmable device. The control unit may also, or instead, include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where the control unit includes a programmable device such as the microprocessor, microcontroller or programmable digital signal processor mentioned above, the processor may further include computer executable code that controls operation of the programmable device. The advantages of the second, third and fourth aspects of the invention are largely analogous to the advantages of the first aspect of the invention.

According to a fifth aspect of the invention, there is provided a system for estimating work cycles of a working operation for a working machine, the system comprising the control unit according to the fourth aspect, including any embodiment thereof.

The advantages of the fifth aspect of the invention are largely analogous to the advantages of the first, second, third and fourth aspects of the invention. Furthermore, the fifth aspect of the invention has a numerous exemplary embodiments, some of which are presented below.

According to at least one exemplary embodiment, the system further comprises sensors for sensing operating steps performed by the working machine and for generating data to be communicated to the control unit. By having data generating sensors, readily obtainable information may be provided for statistics and further analyses.

According to at least one exemplary embodiment, the system further comprises a positioning system, such as a GPS system or other triangulation system, wherein said control unit is configured to define a virtual geographic boundary for said working operation by means of the GPS system. This is advantageous since this allows a certain flexibility, and the working machine does not need to perform exactly the same motion (e.g. directions and distance) for each work cycle of a working operation. There may be certain tolerances as long as the implement, and suitably the working machine, remains within said virtual geographic boundary.

According to at least one exemplary embodiment, said control unit is a central control unit located remotely from the working machine, wherein the system further comprises a local control unit located in the working machine for communicating generated data to the central control unit. This is advantageous since the data may be generated locally, while a central control unit placed remotely from the working machine may perform calculations and statistics based on the data it receives from the local control unit. Furthermore, the central control unit may be configured to communicate and acquire data from a plurality of working machines and their respective local control units. Thus, according to at least one exemplary embodiment, the system comprises a plurality of local control units, each one located in a respective working machine for communicating data to the central control unit. In other exemplary embodiments, said control unit is a local control unit located on the working machine.

Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

In the drawings:

Fig. 1 illustrates a working machine in the form of a wheel loader, for which the inventive method and exemplary embodiments thereof may be carried out,

Fig. 2 is a schematic illustration of a method in accordance with at least one exemplary embodiment of the invention. Fig. 2a is a schematic illustration of a method in accordance with at least another exemplary embodiment of the invention.

Fig. 3 is a schematic illustration of a method in accordance with at least some other exemplary embodiments of the invention.

Fig. 4 schematically illustrates a working machine performing a working operation.

Fig. 5 schematically illustrates a working machine performing another working operation.

Fig. 6 schematically illustrates a working machine performing yet another working operation.

Fig. 7 schematically illustrates a system according to at least one exemplary embodiment of the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION Fig. 1 illustrates a working machine 1 in the form of a wheel loader 1 , for which the inventive method and exemplary embodiments thereof may be carried out. It should be noted however, that the wheel loader 1 is just an example and that the invention may be applied to other working machines, such as articulated haulers, excavators, forwarders and backhoe loaders. Furthermore, the invention is applicable within various technical fields, including industrial construction, agriculture, mining and forestry.

The wheel loader 1 has a forward machine part/front frame 3 and a rear machine part/rear frame 5. Each of the machine parts/frames comprises two drive wheels or road wheels 7. The rear machine part 5 comprises a cab 9 for an operator of the wheel loader 1. The machine parts 3, 5 are connected to each other in such a way that they can pivot relative to each other about a vertical axis by means of one or two hydraulic cylinders (steering cylinders) 1 1a, 1 1 b which are arranged between the machine parts 3, 5 and attached thereto. The hydraulic cylinders 11 a, 1 1 b are thus arranged one on each side of a centre line extending in the longitudinal direction of the working machine 1 in order to turn or steer the wheel loader 1 by means of the hydraulic cylinders 1 1a, 11 b. In other words, the wheel loader 1 is a so called frame-steered working machine. However, it should be understood that the invention is by no means limited to working machines with this type of steering mechanism, and the other working machines with other types of steering mechanisms may also benefit from the implementation of the present invention.

The wheel loader 1 comprises a load arm assembly 13 for handling different loads, such as objects or material. The load arm assembly 13 comprises a lift arm unit 15 and an implement 17 in the shape of a bucket which is mounted on the lift arm unit 15. It should be understood that although the implement 17 has been illustrated as a bucket, in other exemplary embodiments it may be a different object, such as a shovel, forks, gripping tool, material arm or excavating tool.

In the illustrated example the bucket 17 is filled with material 19. A first end of the lift arm unit 15 is pivotally connected to the forward machine part 3 in order to achieve a lift motion of the bucket 17. The bucket 17 is pivotally connected to a second end of the lift arm unit 15 in order to achieve a tilt motion of the bucket 17. The lift arm unit 15 can be raised and lowered relative to the forward machine part 3 of the vehicle by means of two hydraulic cylinders (lift cylinders) 21a, 21 b. Each of the hydraulic cylinders 21 a, 21 b is at a first end thereof coupled to the forward machine part 3 and at the second end thereof to the lift arm unit 15. The bucket 17 can be tilted relative to the lift arm unit 15 by means of a further hydraulic cylinder (tilt cylinder) 23, which at a first end thereof is coupled to the forward machine part 3 and at the second end thereof is coupled to the bucket 17 via a link arm system. The wheel loader 1 may also comprise a drive system (not illustrated) which may include one or more drive units, each of which including a drive motor, a gear box and at least one drive wheel 7. The drive units can be driven independently of each other, i.e. the torque applied by one drive unit can be varied independently of the torque applied by another drive unit.

Depending on what kind of working operations the wheel loader 1 is scheduled to perform, the wheel loader 1 may be controlled to go through various work cycles which may include controlling some or all of the above mentioned components of the wheel loader 1 to operate in various operating steps and to different extents. Fig. 2 is a schematic illustration of a method 100 in accordance with at least one exemplary embodiment of the invention. The method 100 is for estimating work cycles of a working operation for a working machine comprising an implement, the method 100 comprising:

- in a first step S1 , determining a starting location for an implement of the working machine;

- in a second step S2, determining a destination location for the implement,

wherein a completed work cycle comprises the implement being moved from the starting location to the destination location and back to the starting location;

- in a third step S3, determining an expected sequence of operating steps to be performed by the working machine for the work cycle to be completed after the implement has finalized the movement from the starting location to the destination location;

- in a fourth step S4, detecting the operating steps that the working machine performs after the implement has reached its destination location;

- in a fifth step S5, comparing the detected operating steps with the expected sequence of operating steps,

wherein, when the detected operating steps fail to follow said expected sequence of operating steps:

- in a sixth step S6, determining that the working operation is finished and that a final work cycle has been interrupted; and

- in a last step (which is herein referred to as step S8, for reasons which will be clear after the subsequent discussion of Fig. 2a), using working machine data from the interrupted final work cycle in order to virtually completing the interrupted final work cycle into a virtually completed work cycle.

It should be understood that the above steps do not necessarily have to be performed in the listed order. For instance, steps S1 and S2 may be performed simultaneously, or step S2 may even be performed prior to step S1 . Similarly, it is conceivable to have step S4 performed simultaneously with or before step S3, i.e. the expected sequence of operating steps do not necessarily need to be determined prior to the actual detecting of the operating steps.

Fig. 2a is a schematic illustration of a method 100a in accordance with at least another exemplary embodiment of the invention. The method 100a includes all the steps of the method 100 in Fig. 2, however, the method 100a of Fig. 2a includes an additional seventh step S7 between the steps S6 and S8. The seventh step S7 is:

disregarding at least part of the detected operating steps. Furthermore, in the method 100a of Fig. 2a, step S8 may comprise:

extrapolating working machine data from the interrupted final work cycle in order to estimate virtual operating steps completing the interrupted final work cycle into a virtually completed work cycle.

In either one of the methods 100 and 100a the starting location may, in at least some exemplary embodiments, be a location for loading the implement with material, while the destination location may be a location for unloading the material. The material may, for instance, be gravel, stone, timber, crops, etc. In other exemplary embodiments the starting location may be a location for unloading the material, while the destination location may be a location for loading the material. In at least some exemplary embodiments, the entire working machine (including its implement) is moved between the starting location and the destination location as part of a work cycle. This will be exemplified in connection with Fig. 4 and Fig. 5. In other exemplary embodiments, the working machine is parked throughout the work cycle, e.g. the drive/road wheels or tracks, remain stationary on the ground, while the implement is moved. This will be further discussed in connection with Fig. 6.

The third step S3 of determining an expected sequence of operating steps, may comprise detecting a first sequence of operating steps performed by the working machine when moving the implement from the starting location to the destination location, and determining a second sequence of operating steps which are in a reversed order compared to at least a subset of the first operating steps, wherein said expected sequence is said second sequence.

Furthermore, in the third step S3, there may be included a time factor. For instance, an operating step may be for the working machine to return to the starting location within a certain time period after having reached the destination location. If for instance, an operator leaves the working machine at the destination location in order to have a lunch break or ends his/her working day, it may in such case, for instance, be determined that the expected sequence was interrupted and working machine data is extrapolated to complete the interrupted work cycle into a virtually completed work cycle.

As regards the method 100a of Fig. 2a, the seventh step S7 may comprise disregarding the first one of the detected operating steps that breaks the expected sequence of operating steps and any subsequent detected operating steps. In the previous example of the lunch break, pausing of the working machine for a certain time period may for instance be defined as an operating step which breaks the expected sequence. However, in other embodiments, a certain time period may be defined as an idle or pausing time, and the expected sequence may be resumed. Other sequence breaking operating steps may be that the working machine drives in a different direction than expected, a different distance, outside a defined working area, etc.

It should be understood that there may be a number of different operating steps which may be included in the expected sequence of operating steps (true for both methods 100 and 100a), and there may similarly be a number of operating steps that are detected in step S4. Some examples of possible operating steps (expected and/or detected) may include: moving, such as lifting, lowering, rotating and/or tilting, the implement of the working machine,

moving the implement within a defined working area,

moving the implement to a defined intermediate location on its way to the starting location or the destination location,

moving the implement in a defined direction,

moving the implement a defined distance or distance range,

changing movement direction of the implement,

loading or unloading the implement of the working machine,

driving the working machine within a defined working area,

driving the working machine to a defined intermediate location on its way to the starting location or the destination location,

driving the working machine in a defined direction,

driving the working machine a defined distance or distance range,

changing movement direction of the working machine,

loading or unloading the implement of the working machine,

any combination of the above listed actions.

Some of the above operating steps may be detected for example by means of a GPS system or any other suitable positioning system (suitably based on some type of triangulation calculations). Some of the above operating steps may be detected by sensors. For instance, sensors may be operatively connected to different cylinders and drive units. Taking the wheel loader 1 of Fig. 1 as an example, sensors may be operatively connected to one or more of the hydraulic cylinders 1 1 a, 1 1 b, 21 a, 21 b and 23, to one or more drive motors, to one or more drive wheels 7, to a battery of the working machine, and/or to a fuel tank of the working machine. Thereby, data may be acquired on what operating steps are actually performed by the working machine.

It follows that examples of possible working machine data that is used and/or extrapolated in the eighth step S8 may include any one of or any combination of the following vehicle parameter values:

- number of rotations of one or more road wheel of the working machine,

- travel distance of the implement,

- travel distance of the working machine

- steering angle,

- swing angle,

- movement direction of the implement

- driving direction of the working machine,

- pressure in one or more cylinders, such as lift and/or tilt cylinders, of a working machine,

- torque of an engine of the working machine,

- velocity of the working machine,

- time of travel of the working machine,

- energy consumption, such as fuel consumption and/or battery power consumption.

Fig. 3 is a schematic illustration of a method 200 in accordance with at least some other exemplary embodiments of the invention. The method 200 includes a number of optional steps following the steps S1 -S8 of the methods 100 and 100a illustrated in Fig. 2 and Fig. 2a (in Fig. 3 the steps S1 -S8 are for simplicity jointly illustrated as one box).

The method 200 may comprises one or more of the following optional steps:

in a ninth step S9, detecting a driving direction and a distance covered by the working machine when driving to the destination location, wherein an operating step in said expected sequence of operating steps comprises driving the working machine substantially the same distance but in a reverse direction to said driving direction,

in a tenth step S10, defining a virtual geographic boundary for said working operation, such as by means of a GPS system, other positioning system or RFID system or by a defined number of rotations of a drive wheel axis, wherein said expected sequence of operating steps includes moving the implement without crossing said virtual geographic boundary, in an eleventh step S1 1 , determining that the working machine has unloaded material from its implement, wherein said method step S5 of comparing the detected operating steps with said expected sequence of operating steps comprises comparing a first driving direction and first distance driven by the working machine after unloading the material with a second driving direction and second distance driven by the working machine prior to unloading the material, wherein it is determined that the working operation is finished and that a final work cycle has been interrupted if: the direction reverse to the first driving direction is substantially different from the second driving direction, and/or the first driving distance is substantially different from the second driving distance,

in a twelfth step S12, collecting the working machine data representing the virtually completed work cycle, and in a thirteenth step S13, collecting any additional data representing work cycles of said working operation which have been completed before the virtually completed work cycle,

in a fourteenth step S14, after determination that the working operation is finished, determining that the working machine is transported to a new starting location for a new working operation.

Step 12 and Step 13 may be performed in any order or simultaneously. Furthermore, the above mentioned optional steps S9-S14 may be formed individually or in combination with one or more of the other steps.

Fig. 4 schematically illustrates a working machine 1’ performing a working operation. In this illustrated example, the working operation includes picking up material from a starting location 30 (which in Fig. 4 is schematically illustrated as being occupied by a pile or mound of material, such as gravel, stone, crops, etc.) and then transporting the picked-up material to a destination location 40 (which in Fig. 4 is schematically illustrated as being occupied by a load receiver, such as a container) where the working machine 1’ will unload the material and then return back to the starting location 30 in order to be ready to pick up another material batch from the starting location 30, thus completing one work cycle of the working operation. As illustrated in Fig. 4, the working machine 1’ may be driven to an intermediate location 50 (for example for reversing the drive of the working machine) before completing its travel from the starting location 30 to the destination location 40, or vice versa. In more detail, the work cycle may comprise the following operating steps (reference letters indicated in Fig. 4).

A) Picking up the material in the implement (such as a bucket) when the working machine is at the starting location.

B) Leaving the starting location.

C) Retardation of the working machine at the intermediate location.

D) Reversing the driving direction.

E) Driving towards the destination location.

F) Retardation of the working machine.

G) Unloading the material from the implement.

H) Leaving the destination location.

I) Retardation of the working machine at the intermediate location.

J) Reversing the driving direction.

K) Driving towards the starting location.

L) Retardation of the working machine.

These operating steps may, in turn, be divided into substeps. For instance, the unloading of material may be divided into subsets such as lowering the lift arm unit, tilting the bucket in one direction, tilting the bucket in another direct, and/or activating a first cylinder, then activating another cylinder, etc. The different operating steps may be monitored by appropriate sensors which may communicate with a control unit. The operating steps of leaving and approaching the starting location 30 and/or destination location 40 may include detailed specifications or substeps, such as driving a certain distance and/or in a certain direction. Such a distance may be defined as within an interval of distance values. Similarly, the direction does not have to be an exact direction, but could be within an interval of a given number of degrees. Said operating steps, or other operating steps, may also include the condition that the working machine T remains within a defined virtual or real working area 60, illustrated as defined by a dashed boundary in Fig. 4. A virtual working area 60 may, for instance, be created by a control unit and be used with a positioning system, such as a GPS system.

For certain working areas or under certain conditions, GPS systems are not adequate. For instance, in underground mining, GPS signals may be correctly communicated. Other means for determining the position of the implement or the working machine may instead be used. In some exemplary embodiment, a virtual working area 60 may be created by defining for instance, a maximum number of forward or reverse rotations of a wheel axle from one or more defined locations (such as the starting location, the destination location, and/or one or more intermediate locations). If the maximum number is exceeded, it is determined that the working machine has moved outside the virtual working area 60. Such exemplary embodiments may, for instance, be used in underground mining, but may also be used in applications above ground.

In the example of Fig. 4, a complete work cycle includes the operating steps A-L. Assuming that after a number of work cycles the working machine 1’ drives to a different place than the starting location 30 after it has unloaded material, left and reversed up to operating step J, then the operating steps K and L will not be performed, and the final work cycle will not be complete, but becomes interrupted. According to exemplary embodiments of the inventive method, in the example of Fig. 4, after the implement has finalized the movement from the starting location 30 to the destination location 40, the expected sequence of operating steps to be performed are determined to be G-L. Although steps G, H, I and J are detected for the working machine, steps K and L will not be detected, but instead some other operating steps, if any, will be detected. Thus, the detected operating steps fail to follow the expected sequence of operating steps. Any operating step performed after operating step J will be disregarded and the working machine data will be extrapolated in order to estimate virtual operating steps (virtual steps K and L) completing the interrupted final work cycle into a virtually completed work cycle. This information may be sent to a control unit for statistical analysis. The sent data may include information on the number of actually completed work cycles and the virtually completed work cycle for this particular working operation. Acquired information relating to any subsequent work performed by the working machine may then be logged as a separate working operation.

Assuming instead that after a number of work cycles the working machine T drives towards the starting location 30 but does not stop there. Instead the working machine continues to drive past the starting location in order to carry out some other working operation elsewhere. In such case, the expected operating step L has not been detected. Instead, after the operating step K, there is detected a transport to said other working operation elsewhere. According to at least some exemplary embodiments, part of that transport (suitably the segment up to but not past the starting location 30) will be used for virtually completing the interrupted final work cycle. The remaining part of the transport will be classified as a separate transport operation or part of the subsequent working operation. Fig. 5 schematically illustrates a working machine 1” performing another working operation. Similarly, to Fig. 4, the working operation in Fig. 5 has a starting location 30 and a destination location 40. There may also be an intermediate location 50 (for example for reversing the driving direction of the working machine 1”). The working machine 1” may thus perform complete work cycles from the starting location 30 to the destination location 40 and back to the starting location 30. This working operation may be classified by a control unit as a load and carry operation, i.e. the working machine 1” operates over a relatively large distance between the starting location 30 and the destination location 40.

If a driver decides to interrupt such a load and carry operation, and instead picks up material from another pile of material 60, in order to perform a short loading cycle, this will be identified as a different working operation and it will be determined that the first working operation has been interrupted. According to the inventive method the interrupted final work cycle of the first working operation will become virtually completed, by extrapolation of working machine data which predicts how a virtually completed work cycle would have looked like. According to at least some exemplary embodiments, said working operation may be one of a short cycle loading operation, close handling operation, and a load and carry operation, or even a transport operation.

Classifying the work performed by the working machine 1” into different working operations (such as short cycle, close handling, load and carry, etc.) may be based work cycle characteristics (e.g. distance, geographical position, position/height of the implement, position/height of lift arm unit). By means of a positioning system, such as a GPS system, the working operations may be specified in more detail, e.g.“Short Cycle Loading at A” or “Load & Carry from B to C”.

From the above discussions and examples it should be understood that according to at least some exemplary embodiments, part of the transport to the next working operation is used and that part of the transport is virtually put into the interrupted work cycle. In other exemplary embodiments, the extrapolation of working machine data may be achieved by using part of a previous work cycle. In still other exemplary embodiments, an average of several or all previous work cycles from the same position may be taken. According to at least some exemplary embodiments, the extrapolation of working machine data may comprise the following procedure. In order to calculate, for example, an average or a variance of a parameter (such as consumed energy, cycle time, etc.) only the completed steps for the present working operation are taken into account. For instance, the following equation may be used:

where y = average of parameter x for a given working operation

N = the number of defined operating steps in a work cycle

Mi = the number of iterations of operating step / ^' , for the present working operation Xi _j = collected data for step / ^' , iteration j.

In this way the working machine data relating to a certain parameter for the missing steps in the interrupted work cycle become extrapolated with the average value of the completed work cycles. This may be performed for any parameter that one may wish to analyse or include in the statistics. The calculations may, suitably, be corrected, compensated or weighted in order to take into account any distortions (e.g. caused by long pauses or other reasons for which the calculated average of a certain parameter may have been inappropriately skewed). For instance, if measuring energy consumption over time, and the working machine is not in an active mode, but is idle or paused for a long period, than that idle or paused period may be taken into account when assessing the calculated average, and appropriately corrected. Fig. 6 schematically illustrates a working machine T” (in the form of an excavator) performing yet another working operation. Contrary to the working operation illustrated in Figs. 4 and 5, the working machine T” illustrated in Fig. 6 does not move from one location to another, but remains in a parked position. Nevertheless, the implement 70 (such as an excavating tool) is caused to move from a starting location 30 (illustrated as a pile of material) to destination location 40 (illustrated as a container of a load receiving vehicle). Thus, a working cycle of the working operation may comprise operating steps such as picking up material 72 into the implement 70 at the starting location 30, lifting an implement holding arm 74, rotating an upper structure 76 that holds the implement holding arm 74 (the rotation may for instance be within a defined swing angle), tilting the implement 70 to empty material 72 at the destination location 40, moving back the implement holding arm 74 to the starting location 30 and lowering the implement holding arm 74. The detecting of operating steps and determining if any expected operating steps are not performed, as well as the idea of extrapolating working machine data from an interrupted final work cycle in order to estimate virtual operating steps completing the interrupted final work cycle into a virtually completed work cycle, may be performed by a method according to the general inventive concept, just like it may be performed for the other illustrated working operations.

It should be noted that for any one of the illustrated working operations, or any other working operation, even though the expression“final work cycle” is used, it should be understood that the final work cycle, may in some cases be the one and only work cycle performed for a working operation. Thus, if the first work cycle of a working operation is determined to be interrupted, that first work cycle will be considered the interrupted final work cycle.

Fig. 7 schematically illustrates a system 80 according to at least one exemplary embodiment of the invention. More specifically, there is illustrated a system 80 for estimating work cycles of a working operation for a working machine. The dashed rectangle symbolizes the working machine 1

The system 80 comprises a control unit 82 for estimating work cycles of a working operation for the working machine. The control unit 82 is configured to perform the method steps of the inventive method disclosed herein. The system may comprise a plurality of sensors 84 for sensing operating steps performed by the working machine 1”” and for generating data to be communicated to the control unit 82. The system 80 may further comprise a positioning system 86 (such as a GPS system), wherein said control unit 82 is configured to define a virtual geographic boundary for said working operation. By means of the positioning system 86 it can be determined if the working machine 1”” is located inside or outside the virtual geographic boundary (virtual geographic working area).

According to the exemplary embodiment of Fig. 7, the control unit 82 is a central control unit 82 located remotely from the working machine 1””, such as in an office, wherein the system 80 further comprises a local control unit 88 located in the working machine 1”” for communicating generated data to the central control unit 82. Thus, in the present exemplary embodiment the sensors 84 and the positioning system 86 may first send data to the local control unit 88, which may then communicate data (further processed or unprocessed) to the central control unit 82. The central control unit 82 may suitably communicate with other local control units arranged at other working machines.

Although it is advantageous to have a central control unit separate from the working machines, in other exemplary embodiments it would be conceivable to have a local control unit perform the method steps of the inventive method disclosed herein.

It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.