(19)
(11)EP 3 310 970 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
28.08.2019 Bulletin 2019/35

(21)Application number: 15895760.5

(22)Date of filing:  16.06.2015
(51)Int. Cl.: 
E02F 9/26  (2006.01)
E02F 9/20  (2006.01)
G01L 5/00  (2006.01)
E02F 3/43  (2006.01)
G01G 19/08  (2006.01)
(86)International application number:
PCT/SE2015/050704
(87)International publication number:
WO 2016/204660 (22.12.2016 Gazette  2016/51)

(54)

METHOD AND ELECTRONIC CONTROL UNIT FOR DETERMINING A VERTICAL POSITION

VERFAHREN UND ELEKTRONISCHE STEUEREINHEIT ZUR BESTIMMUNG EINER VERTIKALEN POSITION

PROCÉDÉ ET UNITÉ DE COMMANDE ÉLECTRONIQUE PERMETTANT DE DÉTERMINER UNE POSITION VERTICALE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
25.04.2018 Bulletin 2018/17

(73)Proprietor: CPAC Systems AB
412 85 Göteborg (SE)

(72)Inventors:
  • JOHANSSON, Magnus
    423 63 Torslanda (SE)
  • BJÖRE DAHL, Per
    413 20 Göteborg (SE)

(74)Representative: Valea AB 
Box 1098
405 23 Göteborg
405 23 Göteborg (SE)


(56)References cited: : 
EP-A1- 0 979 901
WO-A1-2013/043087
US-A- 5 975 214
US-A- 6 085 583
US-A1- 2010 161 184
WO-A1-2012/054987
JP-A- 2011 252 338
US-A- 5 996 702
US-A1- 2005 046 599
US-A1- 2014 088 838
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] The present disclosure relates to a method for determining the vertical position of at least a point of a ground portion using a work machine comprising an implement. Moreover, the present disclosure relates to a method for levelling a ground area using a work machine comprising an implement. Further, the present disclosure relates to a method for determining a volume of a material entity that is moved from a material body by an implement of a work machine. Additionally, the present disclosure relates to each one of a computer program, a computer readable medium, an electronic control unit, a work machine control system and a work machine.

    BACKGROUND



    [0002] When performing ground modifying operations, such as levelling or material moving operations such as excavating, using a work machine, it may be desired to obtain information as regards the position of a ground portion that has been modified or which is to be modified.

    [0003] To this end, US 5,996,702 proposes a method for operating a work machine tool in which the location of at least a portion of the work machine tool is determined and used for estimating an end result of the work machine tool operation.

    [0004] However, it would be desired to improve the method as proposed in US 5,996,702.

    SUMMARY



    [0005] An object of the present disclosure is to provide a reliable and/or versatile method for obtaining information as regards the position of a ground portion. The above object is achieved by the method according to claim 1.

    [0006] As such, the present disclosure relates to a method for determining the vertical position of at least a point of a ground portion using a work machine comprising an implement. The work machine further comprises position determining means adapted to determine at least the vertical position of the implement and force determining means adapted to determine a force applied to the implement.

    [0007] The method comprises:
    • determining a contact force value indicative of a contact force between the ground portion and the implement using the force determining means;
    • determining whether or not the contact force value is within a predetermined contact force value range, and
    • if it is determined that the contact force value is within the predetermined contact force value range, using the position determining means for determining at least the vertical position of a portion of the implement which is in contact with the ground portion.


    [0008] The above method implies a reliable way of determining whether or not at least a portion of the implement is in contact with the ground portion. This in turn implies that reliable information may be obtained as regards the ground portion position.

    [0009] As used herein, the expression "range" is intended to encompass closed ranges as well as open ranges. For instance, an open range may have an endpoint the absolute value of which is infinity resulting in that the above discussed feature of determining whether or not the contact force value is within a predetermined contact force value range corresponds to a feature of determining whether or not the absolute value of the contact force value is equal to or above a predetermined contact force value threshold value.

    [0010] Optionally, the work machine comprises means for moving the implement, the method further comprising:
    • moving the implement until the contact force value is within the predetermined contact force value range.


    [0011] The above features imply an appropriate manner of obtaining a desired contact force value.

    [0012] Optionally, the work machine comprises means for moving the implement in at least a vertical direction.

    [0013] Optionally, an end point of the predetermined contact force value range is indicative of the weight of the implement.

    [0014] Optionally, the work machine comprises an implement load sensor, and wherein the feature of determining a contact force value comprises using the implement load sensor.

    [0015] A work machine may be furnished with an implement load sensor for other purposes, e.g. to determine a weight of a load in the implement. As such, the use of the implement load sensor implies that the method according to the present disclosure may be performed without necessarily having to furnish the work machine with an additional sensor the sole purpose of which is to determine the contact force between the ground portion and the implement.

    [0016] Optionally, the method further comprises transmitting the vertical position to a data receiver.

    [0017] Optionally, the method further comprises:
    • determining the horizontal position of a portion of the implement and transmitting the horizontal position to the data receiver.


    [0018] Optionally, the method further comprises:
    • using a global navigation satellite system and/or a total station for determining the horizontal position.


    [0019] Optionally, the implement comprises a material receiving portion, adapted to receive material, and a surrounding portion, adapted not to receive material, the feature of determining a contact force value comprising determining a contact force value indicative of the contact force between the ground portion and a portion of the surrounding portion of the implement.

    [0020] A second aspect of the present disclosure relates to a method for levelling a ground area using a work machine comprising an implement. The method comprises:
    • applying a predetermined portion of the implement to the ground portion to thereby level it, and
    • determining the vertical position of at least a point of a ground portion using the method according to the first aspect of the present disclosure.


    [0021] The second aspect of the present disclosure implies an appropriate way to determine at least the vertical position of a levelled ground portion. For instance, at least the vertical position may be determined using the same tool, viz the implement, as has been used for the levelling procedure.

    [0022] A third aspect of the present disclosure relates to a method for determining a volume of a material entity that is moved from a material body by an implement of a work machine, the method comprising:
    • firstly determining the vertical position of at least a point of a ground portion using the method according to the first aspect of the present disclosure and thereafter:
    • moving the material entity from the material body using the implement, the material entity comprising the ground portion,
    • determining at least the vertical position of a material body surface remaining after the implement has moved through the material body, and
    • determining the volume of the material entity using the vertical position of the ground portion and the vertical position of the material body surface.


    [0023] The third aspect of the present disclosure implies an appropriate way to determine at least the vertical position of the ground portion before a material moving operation commences. For instance, at least the vertical position may be determined using the same tool, viz the implement, as will be used for the material moving procedure.

    [0024] Optionally, the method comprises:
    • firstly determining the vertical position of a plurality of points of the ground portion using the method according to the first aspect of the present disclosure to thereby generate a ground portion surface estimate.


    [0025] A fourth aspect of the present disclosure relates to a computer program comprising program code means for performing the computing steps of the first, second or third aspects of the present disclosure when the program is run on a computer.

    [0026] A fifth aspect of the present disclosure relates to a computer readable medium carrying a computer program comprising program code means for performing the computing steps of the first, second or third aspects of the present disclosure when the program product is run on a computer.

    [0027] A sixth aspect of the present disclosure relates to an electronic control unit for a work machine comprising an implement, the work machine further comprises position determining means adapted to determine at least the vertical position of the implement and force determining means adapted to determine a force applied to the implement, the electronic control unit being adapted to:
    • determine a contact force value indicative of a contact force between the ground portion and the implement using the force determining means;
    • determine whether or not the contact force value is within a predetermined contact force value range, and
    • if it is determined that the contact force value is within the predetermined contact force value range, use the position determining means for determining at least the vertical position of a portion of the implement which is in contact with the ground portion.


    [0028] A seventh aspect of the present disclosure relates to a work machine control system comprising an electronic control unit according to the sixth aspect of the present disclosure.

    [0029] An eighth aspect of the present disclosure relates to a work machine comprising a work machine control system according to the seventh aspect of the present disclosure.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0030] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

    [0031] In the drawings:

    Fig. 1 is a schematic side view of a work machine;

    Fig. 2 illustrates an embodiment of a method according to the first aspect of the present invention;

    Fig. 3 illustrates an embodiment of a method according to the second aspect of the present invention;

    Fig. 4 illustrates an embodiment of a method according to the third aspect of the present invention, and

    Fig. 5 illustrates another embodiment of a method according to the third aspect of the present invention.



    [0032] It should be noted that the appended drawings are not necessarily drawn to scale and that the dimensions of some features of the present invention may have been exaggerated for the sake of clarity.

    DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS



    [0033] The invention will be described in the following for a work machine 10 in the form of an excavator such as the one illustrated in Fig. 1. The excavator 10 should be seen as an example of a work machine which could comprise an electronic control unit and/or a work machine control system according to the present invention and/or for which a method according to the present invention could be carried out.

    [0034] The Fig. 1 work machine 10 comprises a main body 12, an implement 14 and a connector 16 connecting the implement 14 to the main body 12. In Fig. 1, the connector 16 comprises a boom 18 and a stick 20. It should be noted that other work machines may comprise a connector with more or fewer components. For instance, it is envisaged that certain work machines, such as a wheeled excavator, may comprise a first boom (not shown) pivotally connected to the main body, a second boom (not shown) pivotally connected to the first boom and a stick pivotally connected to the second boom.

    [0035] The main body 12 has a vertical extension in a vertical direction V. Moreover, and as is indicated in Fig. 1, the main body 12 also has an extension in a longitudinal dimension L in the intended drive direction of the work machine 10 and an extension in a transversal dimension T being perpendicular to each one of the vertical and longitudinal dimensions V, L.

    [0036] Purely by way of example, and as is illustrated in Fig. 1, the boom 18 may be pivotally connected to the main body 12 and may be actuated by a boom actuator 22 connected to each one of the main body 12 and the boom 18. In a similar vein, the stick 20 may be pivotally connected to the boom 18 and may be actuated by a stick actuator 24 connected to each one of the boom 18 and the stick 20. Purely by way of example, at least one, alternatively both, of the boom actuator 22 and the stick actuator 24 may comprise a hydraulic cylinder, such as a double acting hydraulic cylinder. Additionally, the implement 14 may be moveable relative to the stick 20 by means of an implement actuator 26, e.g. a hydraulic implement actuator 26. For instance, the implement 14 may be pivotable relative to the stick 20.

    [0037] Further, the Fig. 1 work machine 10 comprises a force determining means 28 adapted to determine a force applied to the implement 14. In the Fig. 1 embodiment, the force determining means 28 is implemented as an implement load sensor adapted to determine the load of the implement 14. However, it is also envisaged that the force determining means 28 may comprise another type of sensor, e.g. a pressure sensor (not shown).

    [0038] In the Fig. 1 embodiment, the force determining means 28 is located between the implement 14 and the connector 16, e.g. between the implement 14 and the stick 20. However, it is also envisaged that the force determining means 28 may be located in another position such as the implement 14, e.g. in an implementation of the force determining means 28 which comprises a pressure sensor. Further, embodiments are also envisaged in which the force determining means 28 is located on one of the above discussed actuators 22, 24, 26 or in any of the hydraulic loops (not shown) connected to the actuators 22, 24, 26.

    [0039] The Fig. 1 work machine 10 further comprises an electronic control unit 30 which may be adapted to control work machine operations and/or to process data relevant for the operation of the work machine 10. As non-limiting and non-exhaustive examples, the feature "processing data" may include one or more of: determining, storing, transmitting or receiving data.

    [0040] Purely by way of example, the electronic control unit 30 may comprise a computer program comprising program code means for performing the computing steps of any one of the methods that will be presented hereinbelow. For instance, the electronic control unit 30 may comprise a computer readable medium carrying a computer program comprising program code means for performing the computing steps of any one of the methods that will be presented hereinbelow.

    [0041] Further, the work machine 10 comprises position determining means 32 adapted to determine at least the vertical position of the implement 14. As a non-limiting example, such a vertical position may be determined using information indicative of the current condition, e.g. stroke, of each one of the previously discussed actuators 22, 24, 26. However, it is also envisaged that implementations of the position determining means 32 also and/or instead may determine the relative angles between the components, e.g. the the main body 12, the boom 18, the stick 20 and the implement 14, of the work machine 10. Such an implementation of the position determining means 32 may comprise one of more angle gauges or sensors (not shown) adapted to determine the relative angle between at least two components of the connector 16. As a further alternative, the position determining means 32 may instead, or in addition to any one of the above discussed implementations, comprise one or more inclinometer or a more advanced gauge of similar type.

    [0042] The electronic control unit 30 may form part of work machine control system. Such a work machine control system may also comprise the above-discussed position determining means 32.

    [0043] Purely by way of example, and as is illustrated in Fig. 1, the position determining means 32 may be an individual unit in the work machine 10. As another non-limiting example, the position determining means 32 may form part of another unit of the work machine, such as the electronic control unit 30.

    [0044] Additionally, the embodiment of the work machine 10 illustrated in Fig. 1 comprises a global navigation satellite system 34 adapted to determine the position of the work machine 10. A non-exhaustive list of global navigation satellite systems includes: GPS, GLONASS, Galileo or Beidou. Purely by way of example, instead of, or in addition to, a global navigation satellite system, embodiments of the work machine 10 may comprise another type of assembly for determining the position, e.g. the horizontal position, of the work machine 10, e.g. a Total Station (TS), alternatively an Automatic Total Station (ATS).

    [0045] Fig. 1 illustrates the work machine in a levelling operation, i.e. when the implement 14 is moved in relation to the ground 36 in order to smoothen the ground surface 38. As a non-limiting example, during a levelling operation, the implement 14 may be moved in a direction substantially parallel to the intended extension plane of the ground surface 38.

    [0046] However, the Fig. 1 work machine 10 may also be used for other types of operations. Purely by way of example, the work machine 10 may be used in a material moving operation such as digging. As a non-limiting example, a material moving operation may comprise that at least a portion of the implement is moved in a vertical direction as well as a horizontal direction relative to the ground 36 in order to at least partially fill the implement 14 with material.

    [0047] In an operation, such as any one of the operations presented hereinabove, it may be desired to determine the vertical position of at least a point of a ground portion using a work machine comprising an implement.

    [0048] Fig. 2 illustrates an embodiment of a method for determining the vertical position of at least a point of a ground portion 40 using a work machine comprising an implement. The ground portion 40 is a portion, e.g. a point, a delimited area or a delimited volume, of the ground 36. Generally, the ground portion 40 comprises a portion of the ground surface 38.

    [0049] The method comprises:

    S10: determining a contact force value N indicative of a contact force between the ground portion 40 and the implement 14 using the force determining means 28;

    S12 determining whether or not the contact force value N is within a predetermined contact force value range, and

    S14 if it is determined that the contact force value N is within the predetermined contact force value range, using the position determining means 32 for determining at least the vertical position Vi of a portion of the implement 14 which is in contact with the ground portion 40.



    [0050] Purely by way of example, the method comprising the above steps S10, S12 and S14 may be carried out by a control unit, such as the electronic control unit 30 illustrated in Fig. 1. Moreover, it is also envisaged that a control unit, such as the electronic control unit 30 illustrated in Fig. 1, may be adapted to perform method features and/or to control components of a work machine to perform method features of the below discussed embodiments and/or aspects of the present invention.

    [0051] A work machine may comprise means for moving the implement 14, for instance means for moving the implement in at least the vertical direction V. As a non-limiting example, such moving means may comprise the above discussed actuators (not shown in Fig. 2). The method may further comprise moving the implement 14 until the contact force value N is within the predetermined contact force value range.

    [0052] The predetermined contact force value range may be an open range or a closed range. Purely by way of example, an end point of the predetermined contact force value range may be indicative of the weight Wi of the implement. In such an implementation, the range may be formulated in accordance with the following: Wi ≤ N < ∞. It is also envisaged that other embodiments of the above discussed method may comprise other types of ranges, such as f1xWi ≤ N ≤ f2xWi wherein f1 and f2 are range factors. Purely by way of example, the first range factor f1 may be within the range of 0 < f1 ≤ 1 and the second range factor f2 may be substantially larger than 1. Although the above discussed range f1xWi ≤ N ≤ f2xWi has been presented as a closed range, it is also envisaged that at least one of the ends may be open.

    [0053] As has been intimated hereinabove, the force determining means 28 may be implemented as an implement load sensor adapted to determine the load of the implement 14. Such a load sensor may be used for determining the contact force value N indicative of the contact force between the ground portion 40 and the implement 14.

    [0054] For instance, the implement load sensor may be used such that a determined implement load equal to or less than zero is indicative of that the contact force value N is within a predetermined contact force value range.

    [0055] Fig. 2 further illustrates that the implement 14 may comprise a material receiving portion 14', adapted to receive material, and a surrounding portion 14", adapted not to receive material. Purely by way of example, and as is indicated in Fig. 2, the surrounding portion 14" may comprise, or even be constituted by, a convex portion.

    [0056] Further, the feature of determining a contact force value N may comprise determining a contact force value indicative of the contact force between the ground portion 40 and a portion of the surrounding portion 14" of the implement 14.

    [0057] Furthermore, the feature of determining at least the vertical position Vi of a portion of the implement 14 which is in contact with the ground portion 40 may comprise determining at least the vertical position Vi of a predetermined portion of the implement 14 which is in contact with the ground portion 40. As such, rather than requiring information as regards the shape of the entire implement 14, or even the shape of the entire surrounding portion 14", it may be sufficient to be aware of information as regards the shape and position of a predetermined portion of the implement 14.

    [0058] Purely by way of example, and as is indicated in Fig. 2, an example of such a predetermined portion of the implement 14 may comprise, or even be constituted by, a substantially flat portion 17 of the surrounding portion 14" of the implement 14. In the Fig. 2 embodiment, the implement may be oriented such that the substantially flat portion 15 is substantially horizontal or inclined with a known angle. The vertical position of the substantially flat portion 15, or the lowest portion of the substantially flat portion 15 in the event that the substantially flat portion 15 is inclined, will then provide an appropriate estimate of the vertical position of the ground portion 40.

    [0059] Moreover, as another non-limiting example, a lowermost portion of the implement 14 may be regarded as the portion of the implement 14 which is in contact with the ground portion 40. As such, the above discussed feature S14 may comprise using the position determining means 32 for determining at least the vertical position Vi of the lowermost portion of the implement 14.

    [0060] Instead of, or in addition to, any one of the above-discussed implementations, the feature of determining at least the vertical position Vi of the portion of the implement 14 which is in contact with the ground portion 40 may comprise determining at least the vertical position of a reference portion 17 of the implement 14. Purely by way of example, and as is indicated in Fig. 2, the reference portion 17 of the implement may be a tip of the implement 14.

    [0061] As such, if at least the vertical position of the reference portion 17 is determined, it is possible to determine the vertical position of the ground portion 40. For instance, if the vertical position of the reference portion 17, the shape of the implement 14 as well as the orientation of the implement 14 is known, it is possible to determine the vertical position of the ground portion 40. As a non-limiting example, the previously discussed substantially flat portion 15 may be located adjacent to the reference portion 17, viz the tip. As such, using information as regards the position of the reference portion 17 and the substantially flat portion 15, it is possible to determine the vertical position Vi of a portion of the implement 14 which is in contact with the ground portion 40.

    [0062] The determined vertical position Vi of a portion of the implement 14 which is in contact with the ground portion 40, which position Vi for instance may be determined in accordance with any one of the above discussed implementations, is indicative of the vertical position of at least a point of a ground portion 40.

    [0063] As such, when the vertical position Vi is determined, it may be transmitted to a data receiver (not shown), such as a ground data receiver. Purely by way of example, such a data receiver may be located on the work machine (not shown in Fig. 2) or it may be separate from the work machine. Depending on e.g. the position of the data receiver in relation to the work machine, the above discussed transmission may be achieved by one or more wires or, alternatively, wirelessly.

    [0064] Further, the method may also comprise determining the horizontal position of a portion of the implement 14 and transmitting the horizontal position to the data receiver. As a non-limiting example, the horizontal position may be determined using the position determining means and/or the global navigation satellite system that have been discussed in hereinabove with reference to Fig. 1.

    [0065] It is also envisaged that embodiments of the method may comprise transmitting the vertical position Vi and the determined contact force value N to the data receiver. As an example, the vertical position Vi and associated contact force value N may be stored in pairs in the data receiver. It is also envisaged that embodiments of the method may comprise transmitting information as regards the horizontal position as well as the determined contact force value N together with the vertical position Vi.

    [0066] Fig. 3 illustrates an embodiment of a method for levelling a ground area using a work machine comprising an implement. The method comprises applying a predetermined portion 14" of the implement 14 to the ground portion to thereby level it. As is indicated in Fig. 3, the predetermined portion 14" may preferably be the surrounding portion 14" that has been presented hereinabove in relation to Fig. 2. Further, and as is indicated in Fig. 3, the predetermined portion 14" may preferably be a substantially flat portion of the surrounding portion 14".

    [0067] Moreover, as is indicated by the arrows in Fig. 3, the predetermined portion 14" may be moved in a substantially horizontal direction, viz in a direction in a horizontal plane extending in the longitudinal and transversal dimensions L, T.

    [0068] Further, the method comprises determining the vertical position Vi of at least a point of a ground portion 40 using the method according to the first aspect of the present disclosure, e.g. the embodiment of the method that has been presented in relation to Fig. 2.

    [0069] Fig. 4 illustrates an embodiment of a method for determining a volume of a material entity 42 that is moved from a material body by an implement of a work machine.

    [0070] The method comprises firstly determining the vertical position Vi of at least a point of a ground portion 40 using the method according to the first aspect of the present disclosure, e.g. the embodiment of the method that has been presented in relation to Fig. 2.

    [0071] Fig. 4 method further comprises, after the vertical position Vi has been determined:
    • moving the material entity 42 from the material body using the implement 14, the material entity comprising the ground portion 40,
    • determining at least the vertical position of a material body surface 44 remaining after the implement 14 has moved through the material body, and
    • determining the volume of the material entity using the vertical position Vi of the ground portion and the vertical position of the material body surface 40.


    [0072] It should be noted that the above features of the Fig. 4 method need not necessarily be performed in the order listen hereinabove. For instance, the features of determining at least the vertical position of a material body surface 44 and/or determining the volume of the material entity may be performed simultaneously as the implement 14 moves the material entity 42.

    [0073] Purely by way of example, the material entity volume may be determined by integrating, analytically or numerically, the volume enclosed by the ground surface 38 and the material body surface 44 over the width of the implement 14. Assuming that the implement 14 has a constant shape throughout its width and also assuming that the ground surface 38 is constant along the width of the implement, the material entity volume may be determined by determining an area enclosed by a line following the material body surface 44 and a line following the ground surface 38 and multiplying the area thus determined by the width of the implement.

    [0074] The ground surface 38 may be estimated in a plurality of ways. In the embodiment illustrated in Fig. 4, the ground surface 38 is estimated as a horizontal plane the vertical position of which coincides with the vertical position Vi of a single point of the ground portion 40.

    [0075] However, Fig. 5 illustrates an alternative embodiment of the method for determining a volume of a material entity 42 which embodiment comprises firstly determining the vertical position of a plurality of points Vki, Vk+1i, Vk+2i of the ground portion 40 using the method according to the first aspect of the present disclosure to thereby generate a ground portion surface estimate. As such, in the Fig. 4 embodiment, the implement has been positioned at various positions pk, pk+1,pk+2 that are located at a distance from one another in the horizontal plane and for each one of the positions, the vertical position Vki is determined using the method according to the first aspect of the present disclosure. Using the vertical positions Vki, Vk+1i, Vk+2i thus determined and the horizontal coordinates of the corresponding points pk, pk+1, pk+2, an estimate of the ground surface 38 may be generated. As a non-limiting example, such a ground surface estimate may extend in all three dimensions L, T, V.

    [0076] Once the ground surface estimate has been determined, the material entity volume may be determined, for instance in accordance with the procedure that has been presented hereinabove.

    [0077] It is to be understood that the present invention is defined by the appended claims and 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.


    Claims

    1. A method for determining the vertical position of at least a point of a ground portion (40) using a work machine (10) comprising an implement (14), said work machine (10) further comprises position determining means (32) adapted to determine at least the vertical position of said implement (14) and force determining means (28) adapted to determine a force applied to said implement (14), said method comprising:

    - determining a contact force value indicative of a contact force between said ground portion (40) and said implement (14) using said force determining means (28);

    - determining whether or not said contact force value is within a predetermined contact force value range, and

    - if it is determined that said contact force value is within said predetermined contact force value range, using said position determining means (32) for determining at least the vertical position of a portion of said implement (14) which is in contact with said ground portion (40).


     
    2. The method according to claim 1, wherein said work machine (10) comprises means for moving said implement (14), said method further comprising:

    - moving said implement (14) until said contact force value is within said predetermined contact force value range.


     
    3. The method according to claim 1 or claim 2, wherein said work machine (10) comprises means for moving said implement (14) in at least a vertical direction.
     
    4. The method according to any one of the preceding claims, wherein an end point of said predetermined contact force value range is indicative of the weight of said implement (14).
     
    5. The method according to any one of the preceding claims, wherein said work machine (10) comprises an implement (14) load sensor, and wherein the feature of determining a contact force value comprises using said implement (14) load sensor.
     
    6. The method according to any one of the preceding claims, wherein said method further comprises:

    - transmitting said vertical position to a data receiver.


     
    7. The method according to claim 6, wherein said method further comprises:

    - determining the horizontal position of a portion of said implement (14) and transmitting said horizontal position to said data receiver.


     
    8. The method according to claim 7, wherein said method further comprises:

    - using a global navigation satellite system (34) and/or a total station for determining said horizontal position.


     
    9. The method according to any one of the preceding claims, wherein said implement (14) comprises a material receiving portion (14'), adapted to receive material, and a surrounding portion (14"), adapted not to receive material, said feature of determining a contact force value comprising determining a contact force value indicative of the contact force between said ground portion (40) and a portion of said surrounding portion (14")of said implement (14).
     
    10. A method for levelling a ground area using a work machine (10) comprising an implement (14), said method comprising:

    - applying a predetermined portion of said implement (14) to said ground portion (40) to thereby level it, and

    - determining the vertical position of at least a point of a ground portion (40) using the method according to any one of the preceding claims.


     
    11. A method for determining a volume of a material entity that is moved from a material body by an implement (14) of a work machine (10), said method comprising:

    - firstly determining the vertical position of at least a point of a ground portion (40) using the method according to any one of claims 1 to 9 and thereafter:

    - moving said material entity (42) from said material body using said implement (14), said material entity (42) comprising said ground portion (40),

    - determining at least the vertical position of a material body surface (44) remaining after the implement (14) has moved through said material body, and

    - determining said volume of said material entity using said vertical position of the ground portion (40) and said vertical position of said material body surface.


     
    12. The method according to claim 11, said method comprising:

    - firstly determining the vertical position of a plurality of points of said ground portion (40) using the method according to any one of claims 1 to 9 to thereby generate a ground portion surface estimate.


     
    13. A computer program comprising program code means for performing the computing steps of any of claims 1 to 12 when said program is run on a computer.
     
    14. A computer readable medium carrying a computer program comprising program code means for performing the computing steps of any of claims 1 to 12 when said program product is run on a computer.
     
    15. An electronic control unit (30) for a work machine (10) comprising an implement (14), said work machine (10) further comprises position determining means (32) adapted to determine at least the vertical position of said implement (14) and force determining means (28) adapted to determine a force applied to said implement (14), said electronic control unit (30) being adapted to:

    - determine a contact force value indicative of a contact force between said ground portion (40) and said implement (14) using said force determining means (28);

    - determine whether or not said contact force value is within a predetermined contact force value range, and

    - if it is determined that said contact force value is within said predetermined contact force value range, use said position determining means (32) for determining at least the vertical position of a portion of said implement (14) which is in contact with said ground portion (40).


     
    16. A work machine (10) control system comprising an electronic control unit according to claim 15.
     
    17. A work machine (10) comprising a work machine (10) control system according to claim 16.
     


    Ansprüche

    1. Verfahren zum Bestimmen der vertikalen Position wenigstens eines Punkts eines Bodenabschnitts (40) unter Verwendung einer Arbeitsmaschine (10), die ein Gerät (14) umfasst, wobei die Arbeitsmaschine (10) weiterhin ein Positionsbestimmungsmittel (32), das dafür ausgelegt ist, wenigstens die vertikale Position des Geräts (14) zu bestimmen, sowie ein Kraftbestimmungsmittel (28) umfasst, das dafür ausgelegt ist, eine Kraft zu bestimmen, die auf das Gerät (14) aufgebracht wird, wobei das Verfahren umfasst:

    - Bestimmen eines Kontaktkraftwerts, der auf eine Kontaktkraft zwischen dem Bodenabschnitt (40) und dem Gerät (14) hinweist, unter Verwendung des Kraftbestimmungsmittels (28);

    - Bestimmen, ob der Kontaktkraftwert innerhalb eines vorherbestimmten Kontaktkraftwertbereichs liegt oder nicht, und

    - wenn bestimmt wird, dass der Kontaktkraftwert innerhalb des vorherbestimmten Kontaktkraftwertbereichs liegt, Verwenden des Positionsbestimmungsmittels (32) zum Bestimmen wenigstens der vertikalen Position eines Abschnitts des Geräts (14), der mit dem Bodenabschnitt (40) in Kontakt steht.


     
    2. Verfahren nach Anspruch 1, wobei die Arbeitsmaschine (10) ein Mittel zum Bewegen des Geräts (14) umfasst, wobei das Verfahren weiterhin umfasst:

    - Bewegen des Geräts (14), bis der Kontaktkraftwert innerhalb des vorherbestimmten Kontaktkraftwertbereichs liegt.


     
    3. Verfahren nach Anspruch 1 oder Anspruch 2, wobei die Arbeitsmaschine (10) ein Mittel zum Bewegen des Geräts (14) in wenigstens einer vertikalen Richtung umfasst.
     
    4. Verfahren nach einem der vorhergehenden Ansprüche, wobei ein Endpunkt des vorherbestimmten Kontaktkraftwertbereichs auf das Gewicht des Geräts (14) hinweist.
     
    5. Verfahren nach einem der vorhergehenden Ansprüche, wobei die Arbeitsmaschine (10) einen Lastsensor für das Gerät (14) umfasst, und wobei das Merkmal des Bestimmens eines Kontaktkraftwerts das Verwenden des Lastsensors für das Gerät (14) umfasst.
     
    6. Verfahren nach einem der vorhergehenden Ansprüche, wobei das Verfahren weiterhin umfasst:

    - Übermitteln der vertikalen Position an einen Datenempfänger.


     
    7. Verfahren nach Anspruch 6, wobei das Verfahren weiterhin umfasst:

    - Bestimmen der horizontalen Position eines Abschnitts des Geräts (14) und Übermitteln der horizontalen Position an den Datenempfänger.


     
    8. Verfahren nach Anspruch 7, wobei das Verfahren weiterhin umfasst:

    - Verwenden eines globalen Navigationssatellitensystems (34) und/oder einer Totalstation zum Bestimmen der horizontalen Position.


     
    9. Verfahren nach einem der vorhergehenden Ansprüche, wobei das Gerät (14) einen Materialaufnahmeabschnitt (14'), der dafür ausgelegt ist, Material aufzunehmen, sowie einen umgebenden Abschnitt (14") umfasst, der dafür ausgelegt ist, kein Material aufzunehmen, wobei das Merkmal des Bestimmens eines Kontaktkraftwerts das Bestimmen eines Kontaktkraftwerts umfasst, der auf die Kontaktkraft zwischen dem Bodenabschnitt (40) und einem Abschnitt des umgebenden Abschnitts (14") des Geräts (14) hinweist.
     
    10. Verfahren zum Ebnen eines Bodenbereichs unter Verwendung einer Arbeitsmaschine (10), umfassend ein Gerät (14), wobei das Verfahren umfasst:

    - Anwenden eines vorherbestimmten Abschnitts des Geräts (14) an dem Bodenabschnitt (40), um ihn dadurch zu ebnen, und

    - Bestimmen der vertikalen Position wenigstens eines Punkts eines Bodenabschnitts (40) unter Verwendung des Verfahrens nach einem der vorhergehenden Ansprüche.


     
    11. Verfahren zum Bestimmen eines Volumens einer Materialeinheit, die durch ein Gerät (14) einer Arbeitsmaschine (10) von einem Materialkörper bewegt wird, wobei das Verfahren umfasst:

    - zuerst das Bestimmen der vertikalen Position wenigstens eines Punkts eines Bodenabschnitts (40) unter Verwendung des Verfahrens nach einem der Ansprüche 1 bis 9, und anschließend:

    - Bewegen der Materialeinheit (42) von dem Materialkörper unter Verwendung des Geräts (14), wobei die Materialeinheit (42) den Bodenabschnitt (40) umfasst;

    - Bestimmen wenigstens der vertikalen Position einer Materialkörperoberfläche (44), die bleibt, nachdem das Gerät (14) durch den Materialkörper bewegt wurde, und

    - Bestimmen des Volumens der Materialeinheit unter Verwendung der vertikalen Position des Bodenabschnitts (40) und der vertikalen Position der Materialkörperoberfläche.


     
    12. Verfahren nach Anspruch 11, wobei das Verfahren umfasst:

    - zuerst das Bestimmen der vertikalen Position einer Vielzahl von Punkten des Bodenabschnitts (40) unter Verwendung des Verfahrens nach einem der Ansprüche 1 bis 9, um dadurch eine Bodenabschnittsoberflächenschätzung zu erzeugen.


     
    13. Computerprogramm, umfassend Programmcodemittel zum Durchführen der Rechenschritte eines der Ansprüche 1 bis 12, wenn das Programm auf einem Computer läuft.
     
    14. Computerlesbares Medium, auf dem ein Computerprogramm gespeichert ist, das Programmcodemittel zum Durchführen der Rechenschritte nach einem der Ansprüche 1-12, wenn das Programmprodukt auf einem Computer läuft, umfasst.
     
    15. Elektronische Steuereinheit (30) für eine Arbeitsmaschine (10), umfassend ein Gerät (14), wobei die Arbeitsmaschine (10) weiterhin ein Positionsbestimmungsmittel (32), das dafür ausgelegt ist, wenigstens die vertikale Position des Geräts (14) zu bestimmen, sowie ein Kraftbestimmungsmittel (28) umfasst, das dafür ausgelegt ist, eine Kraft zu bestimmen, die auf das Gerät (14) aufgebracht wird, wobei die elektronische Steuereinheit (30) für Folgendes ausgelegt ist:

    - Bestimmen eines Kontaktkraftwerts, der auf eine Kontaktkraft zwischen dem Bodenabschnitt (40) und dem Gerät (14) hinweist, unter Verwendung des Kraftbestimmungsmittels (28);

    - Bestimmen, ob der Kontaktkraftwert innerhalb eines bestimmten Kontaktkraftwertbereichs liegt oder nicht, und

    - wenn bestimmt wird, dass der Kontaktkraftwert innerhalb des vorherbestimmten Kontaktkraftwertbereichs liegt, Verwenden des Positionsbestimmungsmittels (32) zum Bestimmen wenigstens der vertikalen Position eines Abschnitts des Geräts (14), der mit dem Bodenabschnitt (40) in Kontakt steht.


     
    16. System zum Steuern einer Arbeitsmaschine (10), umfassend eine elektronische Steuereinheit nach Anspruch 15.
     
    17. Arbeitsmaschine (10) umfassend ein System zum Steuern einer Arbeitsmaschine (10) nach Anspruch 16.
     


    Revendications

    1. Procédé de détermination de la position verticale d'au moins un point d'une partie de sol (40) en utilisant une machine de travail (10) comprenant un outil (14), ladite machine de travail (10) comprend en outre un moyen de détermination de position (32) adapté pour déterminer au moins la position verticale dudit outil (14) et un moyen de détermination de force (28) adapté pour déterminer une force appliquée audit outil (14), ledit procédé comprenant le fait :

    - de déterminer une valeur de force de contact indiquant une force de contact entre ladite partie de sol (40) et ledit outil (14) en utilisant ledit moyen de détermination de force (28) ;

    - de déterminer si ladite valeur de force de contact est dans une plage de valeurs de force de contact prédéterminée ou non, et

    - s'il est déterminé que ladite valeur de force de contact est dans ladite plage de valeurs de force de contact prédéterminée, d'utiliser ledit moyen de détermination de position (32) pour déterminer au moins la position verticale d'une partie dudit outil (14) qui est en contact avec ladite partie de sol (40).


     
    2. Procédé selon la revendication 1, dans lequel ladite machine de travail (10) comprend un moyen pour déplacer ledit outil (14), ledit procédé comprenant en outre le fait :

    - de déplacer ledit outil (14) jusqu'à ce que ladite valeur de force de contact soit dans ladite plage de valeurs de force de contact prédéterminée.


     
    3. Procédé selon la revendication 1 ou 2, dans lequel ladite machine de travail (10) comprend un moyen pour déplacer ledit outil (14) dans au moins une direction verticale.
     
    4. Procédé selon l'une quelconque des revendications précédentes, dans lequel un point limite de ladite plage de valeurs de force de contact prédéterminée indique le poids dudit outil (14).
     
    5. Procédé selon l'une quelconque des revendications précédentes, dans lequel ladite machine de travail (10) comprend un capteur de charge d'outil (14), et dans lequel l'étape de détermination d'une valeur de force de contact comprend l'utilisation dudit capteur de charge d'outil (14).
     
    6. Procédé selon l'une quelconque des revendications précédentes, dans lequel ledit procédé comprend en outre le fait :

    - de transmettre ladite position verticale à un récepteur de données.


     
    7. Procédé selon la revendication 6, dans lequel ledit procédé comprend en outre le fait :

    - de déterminer la position horizontale d'une partie dudit outil (14) et de transmettre ladite position horizontale audit récepteur de données.


     
    8. Procédé selon la revendication 7, dans lequel ledit procédé comprend en outre le fait :

    - d'utiliser un système mondial de navigation par satellites (34) et/ou un tachéomètre pour déterminer ladite position horizontale.


     
    9. Procédé selon l'une quelconque des revendications précédentes, dans lequel ledit outil (14) comprend une partie de réception de matériau (14'), adaptée pour recevoir un matériau, et une partie environnante (14"), adaptée pour ne pas recevoir un matériau, ladite étape de détermination d'une valeur de force de contact comprenant la détermination d'une valeur de force de contact indiquant la force de contact entre ladite partie de sol (40) et une partie de ladite partie environnante (14") dudit outil (14).
     
    10. Procédé de nivellement d'une zone de sol en utilisant une machine de travail (10) comprenant un outil (14), ledit procédé comprenant le fait :

    - d'appliquer une partie prédéterminée dudit outil (14) à ladite partie de sol (40) pour ainsi la niveler, et

    - de déterminer la position verticale d'au moins un point d'une partie de sol (40) en utilisant le procédé selon l'une quelconque des revendications précédentes.


     
    11. Procédé de détermination d'un volume d'une entité de matériau qui est déplacé à partir d'un corps de matériau par un outil (14) d'une machine de travail (10), ledit procédé comprenant le fait :

    - de déterminer d'abord la position verticale d'au moins un point d'une partie de sol (40) en utilisant le procédé selon l'une quelconque des revendications 1 à 9 et par la suite :

    - de déplacer ladite entité de matériau (42) à partir dudit corps de matériau en utilisant ledit outil (14), ladite entité de matériau (42) comprenant ladite partie de sol (40),

    - de déterminer au moins la position verticale d'une surface de corps de matériau (44) restant après que l'outil (14) a traversé ledit corps de matériau, et

    - de déterminer ledit volume de ladite entité de matériau en utilisant ladite position verticale de la partie de sol (40) et ladite position verticale de ladite surface de corps de matériau.


     
    12. Procédé selon la revendication 11, ledit procédé comprenant le fait :

    - de déterminer d'abord la position verticale d'une pluralité de points de ladite partie de sol (40) en utilisant le procédé selon l'une quelconque des revendications 1 à 9 pour générer ainsi une estimation de surface de partie de sol.


     
    13. Programme informatique comprenant un moyen de code de programme pour effectuer les étapes de calcul de l'une des revendications 1 à 12 lorsque ledit programme est exécuté sur un ordinateur.
     
    14. Support lisible par ordinateur portant un programme informatique comprenant un moyen de code de programme pour effectuer les étapes de calcul de l'une des revendications 1 à 12 lorsque ledit produit de programme est exécuté sur un ordinateur.
     
    15. Unité de commande électronique (30) pour une machine de travail (10) comprenant un outil (14), ladite machine de travail (10) comprend en outre un moyen de détermination de position (32) adapté pour déterminer au moins la position verticale dudit outil (14) et un moyen de détermination de force (28) adapté pour déterminer une force appliquée audit outil (14), ladite unité de commande électronique (30) étant adaptée :

    - pour déterminer une valeur de force de contact indiquant une force de contact entre ladite partie de sol (40) et ledit outil (14) en utilisant ledit moyen de détermination de force (28) ;

    - pour déterminer si ladite valeur de force de contact est dans une plage de valeurs de force de contact prédéterminée ou non, et

    - s'il est déterminé que ladite valeur de force de contact est dans ladite plage de valeurs de force de contact prédéterminée, pour utiliser ledit moyen de détermination de position (32) pour déterminer au moins la position verticale d'une partie dudit outil (14) qui est en contact avec ladite partie de sol (40).


     
    16. Système de commande de machine de travail (10) comprenant une unité de commande électronique selon la revendication 15.
     
    17. Machine de travail (10) comprenant un système de commande de machine de travail (10) selon la revendication 16.
     




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    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description