SYSTEM FOR HANDLING THE SEAMLESS TRANSITION OF BREAKLINES DURING AN EXCAVATION TASK

Abstract

A controller for an excavating machine, comprising a tool, an arm, a set of sensors and a chassis. The sensors being configured to provide data regarding a pose of the tool. The controller comprising an input interface and a computing unit. The input interface is configured to receive operator steering commands. The computing unit is configured to read a design model, comprising two interconnected polygons defining a breakline and to reference the pose of the tool to the design model. The controller is configured for performing a semi-automatic breakline-transition. The semi-automatic breakline-transition function including identifying a breakline-transition move based on the operator steering commands and the pose of the tool with respect to the breakline and generating operator steering command adjustment commands, based on the pose of the tool and the operator steering commands, in order to align the tool to the breakline.

Claims

1. A controller for an excavating machine, the excavating machine comprising a tool comprising a tool edge, an arm comprising multiple links and a tool joint for moving the tool, wherein the tool being attached to the tool joint, a set of sensors configured to provide sensor reading data regarding a position and a heading of the tool, and a chassis, the controller comprising an input interface and a computing unit, the input interface being configured to receive operator steering commands of an operator regarding a desired position and heading and/or movement of the tool, the computing unit being configured to read the operator steering commands and to control the arm to reproduce the desired position and heading and/or movement of the tool, the computing unit being configured to read a design model comprising a reference surface, wherein the reference surface comprising two polygons defining a breakline, the computing unit being configured to reference the position and heading of the tool with respect to the design model, the controller being configured for performing a semi-automatic surface following function, in which operator steering command adjustment commands are generated, based on an actual referenced position and heading of the tool with respect to the design model and on actually read operator steering commands, in order to redirect the tool edge in accordance with the reference surface, the controller being further configured for performing a semi-automatic breakline-transition function including identifying a breakline-transition move based on actually read operator steering commands and based on actual referenced position and heading of the tool with respect to the breakline of the design model, generating operator steering command adjustment commands, based on actual referenced position and heading of the tool with respect to the breakline and on actually read operator steering commands, in order to bring the tool edge to be aligned in parallel with the breakline.

2. The controller according to claim 1, wherein the controller being configured for performing the semi-automatic breakline-transition, generating operator steering command adjustment commands, based on actual referenced position and heading of the tool with respect to the design model and on actually read operator steering commands, in order to bring the tool edge to be aligned in parallel with the breakline, and redirect the tool edge in accordance with the reference surface.

3. The controller according to claim 2, wherein the controller being configured for performing the semi-automatic breakline-transition, generating operator steering command adjustment commands, based on an actual referenced position and orientation of the tool with respect to the design model and on actually read operator steering commands, in order to move the tool edge along a direction of motion perpendicular to the breakline.

4. The controller according to claim 1, wherein the controller being further configured for storing a prior heading data representing the heading of the tool at the activation of the semi-automatic breakline transition function, automatically restoring the heading of the tool after transiting the breakline based on the prior heading data.

5. The controller according to claim 1 wherein the excavating machine being an excavator, the chassis being rotatable to 360, the tool being a bucket, the arm comprising a boom and a stick, the tool joint being a tilt-rotator.

6. The controller according to claim 1, wherein the controller being further configured for performing a semi-automatic parallel operation function, including identifying a parallel operation move based on actually read operator steering commands and based on actual referenced position and heading of the tool with respect to the breakline of the design model, generating operator steering command adjustment commands, based on actual referenced position and heading of the tool with respect to the design model and based on actually read operator steering commands, in order to redirect the tool edge in accordance with the reference surface, redirect the tool edge into a position, wherein the tool edge touching the breakline, and move the tool edge in the reference surface, along the direction of motion parallel to the breakline.

7. The controller according to claim 6, wherein, the set of sensors being configured to acquire sensor reading data comprising information on an actual surface, the controller comprising an output interface, the output interface being configured to display the position and heading of the tool, the reference surface, the actual surface, and a status of the semi-automatic breakline-transition function and/or the semi-automatic parallel operation function, and a guidance feedback comprising the position and heading of the tool relative to the breakline.

8. The controller according to claim 7, wherein the input interface comprising an input area of a touchscreen, the input area being configured to activate and deactivate the semi-automatic breakline-transition function and its options and/or the semi-automatic parallel operation function and its options and/or the guidance feedback and its options.

9. A method of semi-automatic breakline-transition for an excavating machine equipped with a controller of claim 1, the method comprising the steps of, aligning the tool edge in accordance to the reference surface, characterized in that identifying the breakline-transition move based on actually read operator steering commands and based on actual referenced position and heading of the tool with respect to the breakline of the design model, generating operator steering command adjustment commands, based on actual referenced position and heading of the tool with respect to the design model and on actually read operator steering commands, in order to bring the tool edge to be aligned in parallel with the breakline, and redirect the tool edge in accordance with the reference surface.

10. The method according to claim 9, wherein the tool edge being stopped automatically at the breakline.

11. The method according to claim 9, wherein the direction of motion of the tool being automatically aligned to a second polygon at the breakline.

12. The method according to claim 9, wherein the movement of the tool being unsuspended during the alignment of the tool.

13. A method of semi-automatic parallel operation function for an excavating machine equipped with the controller of claim 6, the method comprising the steps of: identifying a parallel operation move based on actually read operator steering commands and based on actual referenced position and heading of the tool with respect to the breakline of the design model generating operator steering command adjustment commands, based on actual referenced position and heading of the tool with respect to the design model and based on actually read operator steering commands, in order to: redirect the tool edge in accordance with the reference surface, redirect the tool edge into a position touching the breakline, and move the tool edge in the reference surface, along the direction of motion parallel to the breakline.

14. A method of semi-automatic parallel operation function for an excavating machine equipped with the controller of claim 8, the method comprising the steps of: identifying a parallel operation move based on actually read operator steering commands and based on actual referenced position and heading of the tool with respect to the breakline of the design model generating operator steering command adjustment commands, based on actual referenced position and heading of the tool with respect to the design model and based on actually read operator steering commands, in order to: redirect the tool edge in accordance with the reference surface, redirect the tool edge into a position touching the breakline, and move the tool edge in the reference surface, along the direction of motion parallel to the breakline.

15. A computer program product for a controller, which, when executed by a computing unit, causes the automatic execution of the steps of the method according to claim 9.

16. A computer program product for a controller, which, when executed by a computing unit, causes the automatic execution of the steps of the method according to claim 12.

17. A computer program product for a controller, which, when executed by a computing unit, causes the automatic execution of the steps of the method according to claim 13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] By way of example only, specific embodiments will be described more fully hereinafter with reference to the accompanying figures, wherein:

[0071] FIG. 1a shows the schematics of an excavator.

[0072] FIG. 1b shows the schematics excavating machine embodied as a tractor equipped with a backhoe excavating arm.

[0073] FIG. 2 shows the schematics of a coordinate system for the tool in respect to the reference surface.

[0074] FIG. 3a shows an example of a breakline defined by two interconnected polygons in the reference surface.

[0075] FIG. 3b shows the prior art of excavating near the breakline.

[0076] FIG. 3c shows the excavating near the breakline.

[0077] FIG. 4a shows the schematics of the movement of the tool in the first polygon during a breakline transition with pose restoring.

[0078] FIG. 4b shows the schematics of the movement of the tool in the second polygon during a breakline transition with pose restoring.

[0079] FIG. 5 shows the schematics of two modes of excavating near the breakline, with a transition and parallel to the breakline.

DETAILED DESCRIPTION

[0080] FIG. 1a depicts a schematics of an embodiment of the excavating machine as an excavator 1. The depicted embodiment comprises a tracked undercarriage 11, a chassis 12, which is rotatable to the undercarriage with about 180 around a rotation axis 110, an excavator arm, and a bucket as a tool 41.

[0081] It is immediately clear for the person skilled in the art that a wheeled undercarriage 11 lies also in the meaning of the present disclosure. Furthermore embodiments, where the chassis 12 is fixed or only a swing movement of the chassis 12 with yaw angle considerably less 180 is allowed in respect to the undercarriage 11 are also within the meaning of the present disclosure.

[0082] The excavating arm comprises a boom 21, in the depicted embodiment a monoboom. The boom 21 is attached to the chassis 12 next to driver cabin 13. Alternative embodiments of the boom 21, in particular knuckle booms, are also within the meaning of the present disclosure. The boom can be at least pitched around a pitching axis 210 in respect to the chassis 12. Alternative embodiments, e.g. where the boom 21 can swing in horizontally in respect to the chassis 12 are also within the meaning of the present disclosure.

[0083] The excavating arm further comprises a stick 22. The stick 22 can swivel around a swivel axis 220. In the depicted embodiment, the excavator 1 utilizes hydraulic cylinders to pitch the boom 21 and the stick 22. Contemporary excavators 1 typically utilize various hydraulic components, however alternative means of driving the components of the excavating arm are also within the meaning of the present disclosure. The excavating arm might be another form of articulated arm. The present disclosure is not limited to the conventional setup.

[0084] The tool 41 is attached to the tool joint at the end of the stick 22. The tool joint in the depicted embodiment is a tilt-rotator 23. A tilt-rotator 23 can best be described as a wrist between the stick 22 and the tool 41, allowing the tool 41 to rotatetypically by 360 degreesabout a rotor axis 230, wherein the tool 41 can further be swiveled, e.g. in each case up to 45 degrees, about a pitch axis 231 perpendicular to the rotor axis 230, and a tilt axis 232 perpendicular to the rotor axis 230 and the pitch axis 231. While the tilt-rotator 23 is especially suitable to realize the technical features of the present disclosure, they are not a mandatory component of an excavating machine according to the present disclosure.

[0085] The tool 41 comprises a tool edge 42. The tool edge might be configured for contacting a surface. In the depicted bucket, the tool edge 42 is the continuous, real edge of the tool 41. For other types of tool 41, in particular teethed buckets or rakes, the tool edge 42 is a fictitious, but definable segment of the tool 41.

[0086] FIG. 1b shows an embodiment of the excavating machine as a backhoe 2 type of excavating machine. The chassis 12 in the depicted embodiment is a tractor. Other type of work machines, in particular bulldozers or loaders, can also serve as the chassis 12, any of these and further alternative embodiments can be utilized to realize the present disclosure.

[0087] The excavating arm, comprising the boom 21 and the stick 22, is attached to a joint 14, and can be swiveled around the rotation axis 110. The boom 21 and the stick 22 can be pitched similarly to that of an excavator 1. The tool joint might be a tilt-rotator 23 or similar or alternative joints with equivalent characteristics. For transparency reasons only the rotor axis 230 is shown in FIG. 1.b. Apart from the mounting of the arm, the backhoe 2 type represents the same options as the excavator 1 type. Consequently, the person skilled in the art could carry out the present disclosure irrespective of the design of the excavating machine. The tool 41 in the here depicted embodiment is a teethed bucket. Other tools 41, in particular other types of buckets, blades, loaders or rakes, might be utilized by an excavating machine according to the present disclosure.

[0088] In some embodiments the excavator arm might be permanently arranged on the chassis, in other embodiments, in particular backhoe 2 type arrangements, it might be an auxiliary equipment temporarily arranged. The present disclosure is not limited to excavating machines with permanently arranged excavator arms.

[0089] FIG. 2 shows the bucket 41 upon establishing contact with the reference surface 50. The depicted area of the reference surface 50, marked as a dashed line, is far away from the breakline and is a flat surface without any further feature. The actual surface marked as the continuous line, can have a shape different than the reference surface 50. In some embodiments the actual surface 60 might be acquired by the set of sensors. In some other embodiments, the bucket 41 is only referenced to the reference surface 50.

[0090] In the depicted embodiment the position of the tool 41, in particular the x,y,z position of the center of the edge 42, is referenced to the reference surface 50, in particular to the polygon the nearest to the edge 42. The direction of motion 46 the tool 41 might also be referenced to the reference surface 50. For an excavator 1 according to the present disclosure, the direction of motion 46 and the orientation of the tool 41 might be independent from each other. This means that the direction of motion 46 of the tool 41 is determined by the orientation of the chassis 12, boom 21 and stick 22, while the orientation of the tool 41 can be independently adjusted by the DoF provided by e.g. a tilt-rotator 23.

[0091] FIG. 2 shows a possible coordinate system relative to the reference surface 50. The orientation of the bucket can be defined utilizing three angles. The angle relative to a plane perpendicular to the Z-axis 44 is traditionally referred as the attack angle, the angle relative to the a plane perpendicular to the X-axis 43 is traditionally referred as the crosscut angle, while the third angle relative to a plane perpendicular to the Y-axis 45 is the heading angle. Alternative definitions of the orientation are within the meaning of the disclosure. Needless to say that the present disclosure is not bound to any specific reference systems, and the person skilled in the art can realize the disclosure using any convenient coordinate system.

[0092] The tool edge 42 might be aligned with the reference surface 50 by the following workflow. The x,y,z position of the tool is chosen so, that the tool 41 is substantially above the reference surface 50, i.e. no changes of the tool orientation might lead to a situation, that a part of the tool 41, in particular the tool edge 42 is below the reference surface 50. The tool 41 is aligned so that the crosscut angle 43 to be 0. The attack angle 44 is aligned so that upon lowering the tool to contact the reference surface 50 no part of the tool 41 will be below the reference surface 50. The tool 41 is lowered to establish contact with the reference surface 50. During the lowering of the tool 41, the attack angle 44 might change. It is clear for the skilled person, that alternatives for this exemplary workflow exist, in particular an alternative workflow might be realized when the tool 41 is near to the reference surface 50, in particular when the tool edge 42 already contacted the reference surface 50. The skilled person could realize a workflow optimized for the specific embodiment of the excavating machine.

[0093] A typical excavator has more DoF than are strictly necessary for the task of grading a planar reference surface 50. This means that the bucket edge 42 can be aligned with the surface using multiple combinations of attack angles 44 and heading angles 45. The attack angle 44 might be optimized depending the excavating task, wherein the heading angle 45 might be optimized so that direction of motion 46 of the tool lays in a plane perpendicular to the tool edge 42. Alternatively the heading angle 45 might be optimized to drive the residues to a given side of the tool 41. For an excavating operation from the left to the right, it is beneficial that the left side stays clean and the residues are driven to the right side.

[0094] FIG. 3a shows an example wherein the reference surface 50 comprises two polygons 51,52. An intersection of the two polygons 51,52 is colloquially known as a breakline 53. The polygon closest to the bucket 41 is defined as the first polygon 51. The direction of motion 46 of the bucket 41 is such that it approaches the breakline 53. The polygon on the other side of breakline is a second polygon 52. A second direction of motion 47 of the tool 41 in the second polygon 52 might be different from the actual direction of motion 46. The direction of motion 46,47 might change at any point during the transition operation. In some embodiments the reference frame might change after transiting the breakline 53. The excavating action might stop at the breakline 53.

[0095] FIG. 3b shows the prior art of excavating near the breakline 53. While the bucket 41 is aligned to the first polygon 51 it is not aligned to the breakline 53. The prior art automatic systems are capable of preventing the tool to break through the reference surface 50 at the second polygon 52, nevertheless the cost of this is the presence of triangular shape residues remaining in the actual breakline 63. To remove the residues a second excavating step is needed, which might even require the repositioning of the excavator 1.

[0096] FIG. 3c shows the excavating near the breakline 53 according to the present disclosure. The heading angle 45 of the bucket is aligned so, that upon reaching the breakline 53 the tool edge 42 is parallel to the breakline. As a result the actual breakline 63 corresponds to the breakline 53 of the reference surface 50 and no second excavating step is required to clean the residues.

[0097] The semi-automatic breakline-transition function includes the identification of a breakline-transition move based on actually read operator steering commands and on actual referenced position and heading 45 of the tool 41 with respect to the breakline 53. The further angular components of the actual referenced pose might also be utilized in the identification of the breakline-transition move. The identification of the breakline transition might be based on the direction of motion 46 or the velocity vector of the tool 41.

[0098] In some embodiments the identification is based on a first criterion. The first criterion comprises the tool edge 42 is essentially parallel to the breakline 53 and the tool 41 is approaching the breakline 53 along a direction of motion 46 essentially perpendicular to the breakline 53. Essentially parallel and essentially perpendicular for the present disclosure means that the operator positioned the tool 41 with the intention of transiting the breakline 53.

[0099] The semi-automatic breakline-transition function further includes generating operator steering command adjustment commands, based on actual referenced pose of the tool with respect to the design model and on actually read operator steering commands, in order to bring the tool edge 42 to be aligned in parallel with the breakline 53.

[0100] In the embodiment depicted on FIG. 3c the operator steering command adjustment commands further comprise the surface following function. While this embodiment of the excavating task is beneficial that it result in an actual surface 60 corresponding the desired reference surface 50 other embodiments are also within the meaning of the present disclosure.

[0101] The excavating task might end at the breakline 53, the excavating task can also continue into the second polygon 52. The bucket 41 might be aligned to the second polygon 52 at the breakline 53. The seamless transition of the breakline 53 and excavating on both polygons 51,52 is an especially beneficial way of using the present disclosure. The present disclosure, however, places no limitation on the excavating tasks to be performed.

[0102] The alignment of the bucket 41 might be carried out during the approach phase in a continuous fashion. The alignment might be carried out in a two-step process, where the movement of the bucket 41 is first put on hold, and the movement continues after the alignment is complete. A semi-automatic alignment process, without a pause or an extra operator action, is an especially beneficial way of using the present disclosure. Embodiments, wherein the alignment is carried out upon a request from the operator are also within the meaning of the present disclosure. In some embodiments guidance feedback might be generated to aid the operator to manually align the tool 41 to the breakline 53, if due to specific circumstances, the operator prefers to carry out a manual alignment.

[0103] FIGS. 4a and 4b shows the schematics in a top view of a breakline transition wherein the orientation of the tool 41 is restored after the transition of the breakline. In the first polygon 51 the tool is moved along a direction of motion 46, the orientation of the tool 41 might be characterized by the crosscut 43, attack 44 and heading angles 45. The tool 41 might be redirected in accordance with the first polygon 51, i.e. the crosscut angle 43 might be 0 and the direction of motion 46 might be parallel to the first polygon 51.

[0104] Upon reaching the breakline 53 the heading 45 of the tool 41 is changed such that the tool edge 42 aligned in parallel with the breakline 53. In the depicted embodiment the alignment executed such that one end of the tool edge 42 is touching the breakline 53. The tool 41 might be redirected at the breakline 53 in accordance to the second polygon 52.

[0105] After transiting the breakline operator steering command adjustment might be generated in order to align the tool to the second orientation and the second direction of motion 47 in respect to the second polygon 52. The second orientation and second direction of motion 47 relative to the second polygon 52 are respectively equal to the prior orientation and direction of motion 46 relative to the first polygon 51 In the depicted embodiment the restoring is executed such that one end of the tool edge 42 is touching the breakline 53. Instead of the directions of motion 46,47 the velocities might be utilized, if having an identical speed of the tool 41 is beneficial.

[0106] FIG. 5 depicts two modes of excavating task near the breakline. In the first type of operation the direction of motion 46 of the bucket 41 intersects the breakline 53 of the first polygon 51 and the second polygon 52. The intent of the operator is at least to reach the breakline 53 or to transit to the second polygon 52. In the second type of operation the bucket 41 has the second direction of motion 47 essentially parallel to the breakline 53, i.e. the intent of the operator in this case is not to transit the breakline 53.

[0107] In some embodiments the controller being further configured to perform a semi-automatic parallel operation function. The semi-automatic parallel operation function comprises identifying a parallel operation based on actually read operator steering commands and based on actual referenced position and heading 45 of the tool 41 with respect to the breakline 53 of the design model.

[0108] In some embodiments the identification is based on a second criterion. The second criterion comprises that the second direction of motion 47 of the tool 41 is essentially parallel to the breakline 53, and the tool edge 42 is essentially touching the breakline 53. Essentially parallel and essentially touching for the present disclosure means that the operator positioned the tool 41 with the intention of excavating parallel to the breakline 53. The direction of motion 46 and second direction of motion 47 are purely descriptive and introduced for readability reasons alone. The two directions of motion 46,47 represent equivalent features.

[0109] Needless to say that alternative formulations for the first and second criteria are possible for the present disclosure. In particular the first and second criteria might also comprise the speed of the tool. Alternatively the first and second criteria might be provided on the basis of the previous excavating actions.

[0110] Although aspects are illustrated above, partly with reference to some specific embodiments, it must be understood that numerous modifications and combinations of different features of the embodiments can be made. All of these modifications lie within the scope of the appended claims.