Method for depositing material

Abstract

A device for depositing residual payload material from an implement of a work machine to a dump region before obtaining a subsequent payload from a dig region. The device is configured to determine wh

Description

Field of the disclosure The disclosure relates to the field of work machines, and in particular to work machines configured to excavate or move material. Background It is known to use a work machine to move material from one location to another. The work machine may excavate the material and then dump the material to a dump location, or may simply move material to a dump location. The dump location may be on the ground, in a truck or vehicle, or elsewhere. The work machine may be operated by a user in the work machine, by a remote user, or autonomously. It is beneficial for productivity and fuel efficiency for a work machine to avoid carrying material back from the dump location to an excavation site or other location (known as carryback material). In other words, it is beneficial for all of the material in or on the implement of the work machine to be deposited at the dump location. A human operating a work machine from the cab of the work machine may make a judgement as to whether there is any material remaining in or on the implement of the work machine after the user has deposited material from the implement. Such a judgement may be visual, such as by inspection of an interior of a bucket or of a quantity of deposited material. The judgement of whether there is any material remaining in or on the implement may be based on other factors, instead of or additionally to a visual judgement. For example, an operator may notice a change in inertia when operating the implement. The operator may also make visual observations of the type of material being moved. Increasingly, work machines are being automated or operated remotely. Visual observations of material that is in or on the implement or that has been deposited at the dump location may not be available, meaning that a remote operator may not be able to rely on such observations to determine whether material remains in or on the implement after depositing material from the implement. Similarly, automated systems for depositing material at dump locations currently operate on limited inputs. A human operating a work machine from the cab of the work machine may also make a judgement as to where to try to remove any carryback material from the implement, and / or as to how to try to remove any carryback material from the implement. A remote operator or an automated system may not have the benefit of visual observations to make those judgements. It is known to remove any carryback material that an operator has identified by vibrating the implement. In the absence of visual observations to check whether or not removal of carryback material is required, vibrating the implement could be carried out each time material is deposited from the implement. However, vibrating the implement too often may increase a risk of wear or damage to the machine. For an automated system that has planned a dump motion (such as a dump trajectory of the implement), vibrating the implement or otherwise moving it in a way that deviates from the planned dump motion may violate path constraints such as avoiding colliding with the ground or other obstacles. It is an object of the present disclosure to provide a method of depositing payload material from a work machine that does not require the visual observations of an in-situ operator, while depositing most or all of the material from the implement to a similar (or better) extent as would be achieved by an in-situ operator and maintaining the health of the machine. Summary of the disclosure Against this background, there is provided a device for depositing residual payload material from an implement of a work machine to a dump region before obtaining a subsequent payload from a dig region, the device configured to: a. determine whether residual payload material is present in the implement; b. in an event that residual payload material is determined to be present in the implement: i. activate a removal mode to deposit the residual payload material at the dump region; and ii. return the implement to the dig region; and c. in an event that residual payload material is determined to not be present in the implement: i. return the implement to the dig region. In this way, residual payload material that had not been removed during a normal excavation cycle may be removed prior to moving the implement back to the dig region, thereby avoiding carrying back material to the dig region. Fuel efficiency may be increased as a result of not carrying back material having a load. Productivity may be increased, since the implement will be empty on return to the dig region and so may excavate a larger volume of material in the next excavation cycle. Furthermore, by determining the deposit trajectory of the implement, depositing residual payload material outside of the dump region is avoided, and any contact of the implement or a linkage with a surface of the dump region may be avoided. There is also provided a method of depositing residual payload material from an implement of a work machine to a dump region before obtaining a subsequent payload from a dig region for remote operation of a work machine, the method comprising: a. determining whether residual payload material is present in the implement; b. in an event that residual payload material is determined to be present in the implement: i. activating a removal mode to deposit the residual payload material at the dump region; and ii. returning the implement to the dig region; c. in an event that residual payload material is determined to not be present in the implement: i. returning the implement to the dig region. Brief description of the drawings A specific embodiment of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows steps carried out by a device configured to or method of depositing residual payload material from an implement of a work machine, according to an embodiment of the present disclosure. Figure 2 shows steps carried out by a device configured to or method of depositing residual payload material from an implement of a work machine, according to an embodiment of the present disclosure. Figure 3 shows steps carried out by a device configured to or method of depositing residual payload material from an implement of a work machine, according to an embodiment of the present disclosure. Figure 4 shows a schematic of an example of a work machine. Figure 5 shows steps carried out by a device configured to or method of depositing residual payload material from an implement of a work machine, according to an embodiment of the present disclosure. Detailed description In use, a work machine may perform dig-dump cycles, also referred to herein as excavation cycles. Each excavation cycle may start with the implement at a dig region or may comprise moving the implement to the dig region. The excavation cycle may then comprise obtaining a payload from a dig region, either by picking up or excavating material from the dig region. The excavation cycle may further comprise moving the implement to a dump region and depositing the payload at the dump region. The excavation cycle may be repeated, moving the implement back to the dig region. A device is provided for depositing residual payload material from an implement of a work machine to a dump region, prior to obtaining a subsequent payload from a dig region. With reference to Figure 1, the device is configured to determine whether residual payload material is present in the implement at 110. Step 110 may be carried out after depositing the payload at the dump region and prior to or during moving the implement back to the dig region. In an event that at 110 residual payload material is determined to be present in the implement (illustrated by arrow 111), at 140 the device is configured to activate a removal mode to deposit the residual payload material at the dump region. At step 150, the device is configured to return the implement to the dig region. In an event that at 110 residual payload material is determined not to be present in the implement (illustrated by arrow 112), the device is configured to return the implement to the dig region at step 150. With reference to Figure 2, in an event that at 110 residual payload material is determined to be present in the implement (illustrated by arrow 111), the device may be configured to determine whether a deposit trajectory of the implement is over the dump region at 120. In an event that the deposit trajectory of the implement is not over the dump region (illustrated by arrow 121), at 130 the device is configured to instruct movement of the implement such that the deposit trajectory of the implement is over the dump region. At 140, the device is further configured to activate a removal mode to deposit the residual payload material at the dump region. In an event that at 120 the deposit trajectory of the implement is over the dump region (illustrated by arrow 122), the device may be configured to carry out step 140 after 120, without carrying out step 130. At step 150, the device is configured to return the implement to the dig region. In an event that at 110 residual payload material is determined not to be present in the implement (illustrated by arrow 112), the device is configured to return the implement to the dig region at step 150. At 110, the device is configured to determine whether residual payload material is present in or on the implement In an event that the load is above the residual threshold, it may be determined that residual payload material is present in the implement. In an event that the load is below the residual threshold, it may be determined that residual payload material is not present in the implement. In certain embodiments, at 110 the device may be configured to use a calibrated zero value 160 to determine whether residual payload material is present in or on the implement. For example, the device may be configured to determine a load on the implement and compare the load to the calibrated zero value. In an event that the load is above the calibrated zero value (or above a residual threshold above the calibrated zero value), the device may determine that there is residual payload present in the implement. In an event that the load is at the calibrated zero value (or below a residual threshold above the calibrated zero value), the device may determine that there is not residual payload present in the implement. With reference to Figure 3, the device may be further configured to excavate a payload from the dig region at 310, return the implement to the dump region at 320 and deposit the payload at the dump region at 330. The device may then be configured to repeat step 110. The device may be configured to select a removal mode from two or more candidate removal modes, prior to activating the removal mode at step 140. Step 140 may further comprise selecting the removal mode. In certain embodiments, the removal mode may be selected from one or more of a shake removal mode, a dump removal mode and a curl removal mode. In the following description of these removal modes, the implement comprises a bucket. The bucket may be connected to the work machine via one or more linkages. However, other implements may be used. In an example illustrated in Figure 4, a work machine 400 may comprise a boom 410 connected to a body of the work machine 440. A first distal end of a stick 420 may be connected to a distal end of the boom 410. A bucket 430 may be connected to a second distal end of the stick 420. The boom 410 may be rotated relative to the body 440 using a first hydraulic cylinder 411. The stick 420 may be rotated relative to the boom 410 using a second hydraulic cylinder 421. The bucket 430 may be rotated relative to the stick 420 using a third hydraulic cylinder 431. The angle of the bucket 430 to the stick 420 is illustrated by arrow 450. In use, curling the bucket may comprise decreasing the angle 450 between the bucket 430 and the stick 410 in the direction shown by the arrow (making any loose material in the bucket less likely to fall out of the bucket). Dumping the bucket may comprise increasing the angle 450 between the bucket 430 and the stick 410 in the opposite direction to the direction shown by the arrow (making any loose material in the bucket more likely to fall out of the bucket). The shake removal mode may comprise alternating motion of the implement. The frequency and magnitude of the alternating motion may be any suitable values. For example, the shake removal mode may comprise high frequency, low magnitude vibration of the implement. Or, the shake removal mode may comprise lower frequency, higher magnitude movements of the bucket. The shake removal mode may move the bucket back and forth between a larger angle (relative to the stick or any other linkage connecting the bucket to the work machine) that may allow material to tip out of the bucket and a smaller angle. The shake removal mode may comprise alternating rotation of the bucket, and / or alternating linear motion of the bucket. The dump removal mode may comprise dumping the implement out (increasing the angle of the bucket with respect to the linkage) and, while dumping the implement, abruptly preventing movement of implement. In doing so, residual payload material may be dislodged from the bucket. The dump removal mode may be particularly appropriate in an event that a starting angle of the bucket is partially dumped. For an example, in an event that the angle of the bucket to the stick is between the smallest angle to the stick and a centre angle. The centre angle may be halfway between the smallest angle to the stick and the largest angle to the stick. In another example, a hydraulic cylinder that is configured to move the bucket may be more than 50% extended. Curling the implement in may comprise decreasing the angle of the bucket with respect to the linkage. The curl removal mode may comprise curling the implement in and, while curling the implement, abruptly preventing movement of implement. In doing so, residual payload material may be dislodged from the bucket. The curl removal mode may be particularly appropriate in an event that a starting angle of the bucket is more than 50% dumped. For an example, in an event that the angle of the bucket to the stick is between the largest angle to the stick and the centre angle. In another example, a hydraulic cylinder that is configured to move the bucket may be less than 50% extended. In certain embodiments, a removal mode may comprise a combination of two or more of the shake removal mode, dump removal mode and curl removal mode. The shake removal mode, dump removal mode and curl removal mode may each result in dislodging residual payload material from the bucket. If the bucket 430 is at an angle 450 to the stick 420 that allows the dislodged residual payload material to fall out of the bucket (or the angle of the bucket to a gravity vector is such that dislodged residual payload material is allowed to fall out of the bucket), the removal mode may simply be deactivated by ending the removal mode and the implement may be returned to the dig region. However, if the bucket 430 is at an angle 450 to the stick 420 that does not allow the dislodged residual payload material to fall out of the bucket (or the angle of the bucket to a gravity vector is such that dislodged residual payload material is not allowed to fall out of the bucket), the removal mode may further comprise dumping the bucket to increase the angle between the bucket 430 and the stick 420, to allow the dislodged residual payload material to fall out of the bucket 430. With reference to Figure 5, at 140 the device may be configured to carry out two or more sub-steps. The device may be configured to select a removal mode from two or more candidate removal modes at 141. In certain embodiments, the device may be configured to activate the removal mode at 142, to dwell in the removal mode at 143 until the residual payload material is released from the implement, and to deactivate the removal mode at 144. In certain embodiments, the device may be configured to dwell in the removal mode (to continue to instruct operation of the implement in the removal mode) at 143 for a removal time period. In other embodiments, the device may be configured to continue to operate the removal mode until a load of the implement is detected to have a zero payload value or a payload value below a threshold payload. In other words, the device may be configured to determine when the residual payload material has been released from the implement. The device may be configured to use a calibrated zero value 160 to determine whether residual payload material is present in or on the implement. For example, the device may be configured to determine a load on the implement and compare the load to the calibrated zero value. In an event that the load remains above the calibrated zero value (or above a residual threshold above the calibrated zero value), the device may determine that there is still residual payload present in the implement and may continue to dwell in the removal mode. In an event that the load drops to the calibrated zero value (or drops below the residual threshold above the calibrated zero value), the device may determine that there is no longer residual payload present in the implement, and may deactivate the removal mode. At 120, the device is configured to determine whether a deposit trajectory of the implement is over the dump region. The deposit trajectory may comprise a trajectory of the material being dumped from the implement, such that in an event that the deposit trajectory is over the dump region any deposited material will fall on the dump region. The device may be configured to determine the deposit trajectory using velocity data and / or position date obtained from one or more sensors of the work machine. In certain embodiments, at 120 the device may be further configured to determine whether a pose of the work machine is suitable for depositing residual payload material without the implement impacting a surface of the dump region or other material at the dump region. In an event that the pose of the work machine is not suitable for depositing residual payload material, the device may be configured to instruct adjustment of the pose of the work machine such that the pose is suitable for depositing residual payload material without the implement impacting a surface of the dump region. Adjustment of the pose of the work machine may comprise altering an angle of a component of the work machine. Adjustment of the pose of the work machine may comprise altering a distance and angle of the implement relative to the work machine. For example, adjusting the pose of the work machine may comprise raising a linkage of the work machine, such as a boom, such that dumping out the implement (such as a bucket) does not cause the implement to impact the ground or a surface of the dump region. Adjusting the pose of the work machine may comprise altering an angle of a linkage or of the implement. In successive iterations of excavation cycles, the device may be configured to carry out step 110 of determining whether a residual payload is present for each excavation cycle. In other words, the device may be configured to check for the presence of residual payload material during every excavation cycle. In other embodiments, the device may be configured to check for the presence of residual payload material in some, but not all, excavation cycles. In an event that residual payload material is present in more than a certain number of successive excavation cycles (or in more than a certain proportion of successive excavation cycles), the device may be configured to skip step 110 in some excavation cycles, and go straight to step 120. In other words, in an event that residual payload material is found in or on the implement during a certain number of consecutive excavation cycles (or in more than a certain proportion of successive excavation cycles) it may be assumed that residual payload material is likely to be found in one or more subsequent excavation cycles. The device may be configured to carry out step 110 in a first excavation cycle then, during subsequent excavation cycles, the device may be further configured to determine whether to carry out step 110 or whether to skip step 110 based on data from previous dump cycles of the work machine. For example, in an event that residual payload material is determined to be present in the implement during a certain number of consecutive dump cycles of the work machine, the device may be configured to skip step 110 during at least the next excavation cycle following said certain number of consecutive excavation cycles. The device may be configured to skip step 110 for a second number of consecutive excavation cycles. After the second number of consecutive excavation cycles, the device may be configured to once again perform step 110. In an event that no residual payload material is present, the device may be configured to perform step 110 as usual in each subsequent excavation cycle. In an event that residual payload material is present, the device may be configured to skip 110 for a third number of consecutive excavation cycles, and so on. In another example, the device may initially check for the presence of residual payload material in every excavation cycle. In an event that residual payload material is present in two consecutive excavation cycles, the device may be configured to check for the presence of residual payload material in every other excavation cycle. In between, the device may be configured to skip step 110. In an event that residual payload material continues to be present, the device may be configured to check for the presence of residual payload material in every four excavation cycles, and in between the device may be configured to skip step 110. Other multipliers may be used, such that in an event that residual payload material is present in n consecutive excavation cycles, the device may be configured to check for the presence of residual payload material in every m excavation cycle. In an event that residual payload material continues to be present, the device may be configured to check for the presence of residual payload material in every p excavation cycles, m and p may each be a multiple of n, and p may be larger than m. In another example, the device may initially check for the presence of residual payload material in every excavation cycle. In an event that residual payload material is present, the device may be further configured to compare a quantity of the residual payload material to a threshold load. In an event that the quantity of the residual payload material is above the threshold load, the device may be configured to skip step 110 in the next n excavation cycles, before once again carrying out step 110 in the following excavation cycle. In an event that residual payload material is present in that excavation cycle, the device may be further configured to compare a quantity of the residual payload material to the threshold load. In an event that the quantity of the residual payload material is again above the threshold load, the device may be configured to skip step 110 in the next m excavation cycles, and so on. In another example, for a certain number of previous dump cycles where step 110 has been carried out, the device may be configured to skip step 110 during at least the next dump cycle in an event that a proportion of the second number of dump cycles where residual payload material was determined to be present at step 110 is higher than a threshold. The device may be configured to carry out step 110 during at least the next dump cycle in an event that a proportion of the second number of dump cycles where residual payload material was determined to be present at step 110 is lower than a threshold. In other words, for n previous dump cycles where step 110 has been carried out, residual payload material may be determined to be present for m dump cycles of the n dump cycles (where m is less than or equal to n). In an event that a ratio of m / n is higher than a threshold, the device may be configured to skip step 110 during at least the next dump cycle. In an event that a ratio of m / n is lower than the threshold, the device may be configured to carry out step 110 during at least the next dump cycle. In an event that the device is configured to skip step 110 in a particular excavation cycle, step 120 onwards may be carried out after depositing the payload at the dump region or during depositing the payload at the dump region. A method is provided depositing residual payload material from an implement of a work machine to a dump region before obtaining a subsequent payload from a dig region for remote operation of a work machine. The method may comprise any of the steps described herein with relation to the device. Any of the above description may apply to the method. The method comprises determining whether residual payload material is present in the implement. In an event that residual payload material is determined to be present in the implement, the method comprises determining whether a deposit trajectory of the implement is over the dump region and in an event that the deposit trajectory of the implement is not over the dump region, moving the implement such that the deposit trajectory of the implement is over the dump region. The method further comprises activating a removal mode to deposit the residual payload material at the dump region. The method further comprises returning the implement to the dig region. In an event that residual payload material is determined to not be present in the implement, the method comprises returning the implement to the dig region.

Claims

1. A device for depositing residual payload material from an implement of a work machine to a dump region before obtaining a subsequent payload from a dig region, the device configured to:a. determine whether residual payload material is present in the implement;b. in an event that residual payload material is determined to be present in the implement:i. activate a removal mode to deposit the residual payload material at the dump region; andii. return the implement to the dig region; andc. in an event that residual payload material is determined to not be present in the implement:i. return the implement to the dig region.

2. The device of claim 1, wherein at b)i) the device is further configured to select the removal mode from more than one removal mode.

3. The device of claim 1 or 2, wherein prior to activating the removal mode the device is configured to determine whether a deposit trajectory of the implement is over the dump region and in an event that the deposit trajectory of the implement is not over the dump region, instruct movement of the implement such that the deposit trajectory of the implement is over the dump region.

4. The device of any preceding claim, wherein prior to activating the removal mode the device is further configured to determine whether a pose of the work machine is suitable for depositing residual payload material without the implement impacting material at the dump region, and in an event that the pose of the work machine is not suitable for depositing residual payload material instruct adjustment of the pose of the work machine such that the pose is suitable for depositing residual payload material without the implement impacting material at the dump region.

5. The device of any of claims 2 to 4, wherein the removal mode is selected from one or more of:a shake removal mode, comprising alternating motion of the implement;a dump removal mode, comprising: dumping the implement out; and while dumping the implement, abruptly preventing movementof implement; anda curl removal mode, comprising:curling the implement in; andwhile curling the implement, abruptly preventing movement of implement.

6. The device of any preceding claim, wherein step b)i) further comprises continuing to operate the removal mode until a load of the implement is detected to have a zero payload value or a payload value below a threshold payload.

7. The device of any of claims 1 to 5, wherein step b)i) further comprises continuing to operate the removal mode for a removal time period.

8. The device of any of claims 4 to 7 wherein in an event that the pose of the work machine is not suitable for depositing residual payload material the device is configured to instruct one or more of:altering an angle of a component of the work machine; andaltering a distance and angle of the implement relative to the work machine.

9. The device of claim 8, wherein in an event that the pose of the work machine is not suitable for depositing residual payload material the device is configured to instruct one or more of:raising a boom of the work machine; and increasing or decreasing curl of the implement10. The device of any of claims 3 to 9, wherein to determine whether a deposit trajectory of the implement is over the dump region the device is configured to use velocity data obtained from one or more sensors of the work machine.

11. The device of any preceding claim, wherein at step a) the device is configured to compare a load of the implement to a residual threshold, wherein:in an event that the load is above the residual threshold it is determined that residual payload material is present in the implement; andin an event that the load is below the residual threshold it is determined that residual payload material is not present in the implement.

12. The device of any preceding claim, wherein in an event that residual payload material is determined to be present in the implement the device is further configured to determine whether to carry out step a) or whether to skip step a) during the next dump cycle based on data from previous dump cycles of the work machine.

13. The device of claim 12, wherein in an event that residual payload material is determined to be present in the implement during a first number of consecutive dump cycles of the work machine, the device is configured to skip step a) during at least the next dump cycle after the first number of consecutive dump cycles.

14. The device of claim 12, wherein, for a second number of previous dump cycles where step a) has been carried out, the device is configured to:skip step a) during at least the next dump cycle in an event that a proportion of the second number of dump cycles where residual payload material was determined to be present at step a) is higher than a threshold; andcarry out step a) during at least the next dump cycle in an event that a proportion of the second number of dump cycles where residual payload material was determined to be present at step a) is lower than a threshold.

15. A method of depositing residual payload material from an implement of a work machine to a dump region before obtaining a subsequent payload from a dig region for remote operation of a work machine, the method comprising:a. determining whether residual payload material is present in the implement;b. in an event that residual payload material is determined to be present in the implement:i. activating a removal mode to deposit the residual payload material at the dump region; andii. returning the implement to the dig region;c. in an event that residual payload material is determined to not be present in the implement:i. returning the implement to the dig region.517

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