A drive system for a work machine, a work machine, a control device for a work machine, a method for controlling a work machine, and a control program for a work machine.

Abstract

This prevents the attachment from colliding with the vehicle body. [Solution] The drive system for the work machine includes an attachment having a first member and a second member, a drive unit that drives the attachment, and a control device that controls the drive unit. The control device stores positional relationship information that shows the correspondence between the first angular position of the first member and the second angular position of the second member and the positional relationship between the vehicle body and the attachment. The control device performs an acquisition process (step S10) to acquire the first angular position and the second angular position, a calculation process (step S20) to calculate the positional relationship by applying the first angular position and the second angular position to the positional relationship information, and a countermeasure process (step S40) to take measures to avoid interference between the attachment and the vehicle body if the positional relationship indicates that the shortest distance between the attachment and the vehicle body is less than a predetermined value (step S30: YES).

Description

TECHNICAL FIELD

[0001] The present invention relates to a drive system for a work machine, a work machine, a control device for a work machine, a control method for a work machine, and a control program for a work machine.

BACKGROUND ART

[0002] The excavator disclosed in Patent Document 1 includes a vehicle body and an attachment. The attachment has a swing bracket, a boom, an arm, a bucket, and the like. The vehicle body includes an operator's seat and the like. The swing bracket is connected to the vehicle body. The swing bracket rotates about an axis extending vertically relative to the vehicle body. The boom is connected to the swing bracket. The boom rotates about an axis intersecting the axis of the swing bracket. The arm is connected to the distal end of the boom. The arm rotates about an axis parallel to the axis of the boom. The bucket is connected to the distal end of the arm. The arm rotates about an axis parallel to the axis of the boom.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0003]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In an excavator such as that disclosed in Patent Document 1, it is desirable to widen the movable range of each rotary element in the attachment, such as the boom and the arm, in order to expand the working range. However, if the movable range of each rotary element is widened, the attachment can move to the vicinity of the vehicle body. In some cases, the attachment may collide with the vehicle body.

MEANS FOR SOLVING THE PROBLEMS

[0005] A drive system for a work machine to solve the above problems comprises an attachment having a first member rotatably connected to the body of the work machine and a second member rotatably connected to the first member; a drive unit having a first drive device for driving the first member and a second drive device for driving the second member; a first sensor for detecting a first angular position which is the angular position of the first member; a second sensor for detecting a second angular position which is the angular position of the second member; and a control device for executing drive control for controlling the drive unit, wherein the control device performs an acquisition process to acquire the first angular position and the second angular position during the execution of the drive control; and a countermeasure process to take measures to avoid interference between the attachment and the body based on the first angular position and the second angular position acquired in the acquisition process.

[0006] In the drive system of the above-mentioned work machine, measures are taken to avoid interference between the attachment and the vehicle body based on the first and second angular positions. This prevents the attachment from colliding with the vehicle body.

[0007] In a drive system for a work machine, the control device may, in the handling process, control the first drive unit to stop the operation of the first member and control the second drive unit to stop the operation of the second member.

[0008] In a drive system for a work machine, the control device pre-stores positional relationship information indicating the correspondence between the first angular position and the second angular position and the positional relationship between the vehicle body and the attachment. The control device may perform a calculation process to calculate the positional relationship by applying the first angular position and the second angular position acquired in the acquisition process to the positional relationship information. If the positional relationship calculated in the calculation process indicates that the shortest distance between the attachment and the vehicle body is less than a predetermined value, the control device may perform the corrective action.

[0009] In a drive system for a work machine, the positional relationship information represents the correspondence between the first angular position and the second angular position and an index value indicating whether the shortest distance is less than a predetermined value. The control device may calculate the index value as the positional relationship in the calculation process by applying the first angular position and the second angular position acquired in the acquisition process to the positional relationship information.

[0010] In a drive system for a work machine, the positional relationship information includes model information that simulates the work machine in a virtual coordinate system, the model information includes vehicle body coordinate information indicating the position coordinates of each part of the vehicle body placed at a predetermined reference position in the virtual coordinate system, first coordinate information indicating the position coordinates of each part of the first member when the vehicle body is placed at the reference position, and a first relational expression that expresses the relationship between the first angular position and the model information, the control device may, in the calculation process, calculate the first coordinate information by applying the first angular position to the first relational expression, and calculate the second coordinate information by applying the first angular position and the second angular position to the second relational expression, and calculate the shortest distance as the positional relationship based on the calculated first coordinate information, the second coordinate information and the vehicle body coordinate information.

[0011] In a drive system for a work machine, the first drive unit may use a first electric motor as its drive source, and the second drive unit may use a second electric motor as its drive source. In a drive system for a work machine, the first member may be a swing bracket that rotates about a first axis extending vertically from the vehicle body, and the second member may be a boom that rotates about a second axis intersecting the first axis.

[0012] In the drive system for the work machine, the attachment has an arm rotatably connected to the boom and rotating about a third axis parallel to the second axis, and a work member rotatably connected to the arm and rotating about a fourth axis parallel to the second axis, and the drive unit has a third drive device that drives the arm with a third electric motor as the drive source, and a fourth drive device that drives the work member with a fourth electric motor as the drive source, and includes a third sensor that detects a third angular position which is the angular position of the arm, and a fourth sensor that detects a fourth angular position which is the angular position of the work member, and the control device has the first angle Positional relationship information indicating the correspondence between the degree position, the second angle position, the third angle position, and the fourth angle position and the positional relationship between the vehicle body and the attachment is stored in advance. The acquisition process acquires the first angle position, the second angle position, the third angle position, and the fourth angle position. A calculation process is performed to calculate the positional relationship by applying the first angle position, the second angle position, the third angle position, and the fourth angle position acquired in the acquisition process to the positional relationship information. The corrective action process may be performed if the positional relationship calculated in the calculation process indicates that the distance between the attachment and the vehicle body is less than a predetermined value.

[0013] A work machine for solving the above problems comprises a vehicle body, an attachment having a first member rotatably connected to the vehicle body and a second member rotatably connected to the first member, a drive unit having a first drive device for driving the first member and a second drive device for driving the second member, a first sensor for detecting a first angular position which is the angular position of the first member, a second sensor for detecting a second angular position which is the angular position of the second member, and a control device for executing drive control for controlling the drive unit, wherein the control device performs an acquisition process for acquiring the first angular position and the second angular position during the execution of the drive control, and a countermeasure process for taking measures to avoid interference between the attachment and the vehicle body based on the first angular position and the second angular position acquired in the acquisition process.

[0014] In the above-described work machine, measures are taken to avoid interference between the attachment and the vehicle body based on the first and second angular positions. This prevents the attachment from colliding with the vehicle body.

[0015] A control device for a work machine to solve the above problems is applied to a work machine comprising: an attachment having a first member rotatably connected to a vehicle body and a second member rotatably connected to the first member; a drive unit having a first drive device for driving the first member and a second drive device for driving the second member; a first sensor for detecting a first angular position which is the angular position of the first member; and a second sensor for detecting a second angular position which is the angular position of the second member. The control device performs an acquisition process to acquire the first angular position and the second angular position during the execution of drive control for controlling the drive unit, and a countermeasure process to take measures to avoid interference between the attachment and the vehicle body based on the first angular position and the second angular position acquired in the acquisition process.

[0016] According to the control device described above, measures are taken to avoid interference between the attachment and the vehicle body based on the first and second angular positions. This prevents the attachment from colliding with the vehicle body.

[0017] The control device for the work machine has in advance stored positional relationship information indicating the correspondence between the first angular position and the second angular position and the positional relationship between the vehicle body and the attachment. The control device may perform a calculation process to calculate the positional relationship by applying the first angular position and the second angular position acquired in the acquisition process to the positional relationship information. If the positional relationship calculated in the calculation process indicates that the shortest distance between the attachment and the vehicle body is less than a predetermined value, the control device may perform the corrective action.

[0018] In a control device for a work machine, the positional relationship information represents the correspondence between the first angular position and the second angular position and an index value indicating whether or not the shortest distance is less than the predetermined value. In the calculation process, the index value may be calculated as the positional relationship by applying the first angular position and the second angular position acquired in the acquisition process to the positional relationship information.

[0019] In a control device for a work machine, the positional relationship information includes model information that simulates the work machine in a virtual coordinate system, the model information includes body coordinate information indicating the position coordinates of each part of the body placed at a predetermined reference position in the virtual coordinate system, first coordinate information indicating the position coordinates of each part of the first member when the body is placed at the reference position, and a first relational expression that expresses the relationship between the first angular position and the model information, the model information includes body coordinate information indicating the position coordinates of each part of the second member when the body is placed at the reference position, and a second relational expression that expresses the relationship between the first angular position and the second angular position, the calculation process may calculate the first coordinate information by applying the first angular position to the first relational expression, and the second coordinate information by applying the first angular position and the second angular position to the second relational expression, and the shortest distance may be calculated as the positional relationship based on the calculated first coordinate information and second coordinate information and the body coordinate information.

[0020] A control method for a work machine to solve the above problems is provided, which is applied to a work machine comprising: an attachment having a first member rotatably connected to a vehicle body and a second member rotatably connected to the first member; a drive unit having a first drive device for driving the first member and a second drive device for driving the second member; a first sensor for detecting a first angular position which is the angular position of the first member; and a second sensor for detecting a second angular position which is the angular position of the second member. The control device performs an acquisition process to acquire the first angular position and the second angular position while executing drive control to control the drive unit; and a countermeasure process to take measures to avoid interference between the attachment and the vehicle body based on the first angular position and the second angular position acquired in the acquisition process.

[0021] According to the above method, measures are taken to avoid interference between the attachment and the vehicle body based on the first and second angular positions. This prevents the attachment from colliding with the vehicle body.

[0022] A control program for a work machine to solve the above problems causes a control device applied to a work machine comprising: an attachment having a first member rotatably connected to a vehicle body and a second member rotatably connected to the first member; a drive unit having a first drive device for driving the first member and a second drive device for driving the second member; a first sensor for detecting a first angular position which is the angular position of the first member and a second sensor for detecting a second angular position which is the angular position of the second member; to execute an acquisition process for acquiring the first angular position and the second angular position while executing drive control for controlling the drive unit; and a countermeasure process for taking measures to avoid interference between the attachment and the vehicle body based on the first angular position and the second angular position acquired in the acquisition process.

[0023] According to the above program, it is possible to cause the work machine to perform a measure for avoiding interference between the attachment and the vehicle body based on the first angular position and the second angular position. Thereby, collision of the attachment with the vehicle body can be prevented in advance. [Effects of the Invention]

[0024] In the above technical idea, collision of the attachment with the vehicle body can be prevented in advance. [Brief Description of the Drawings]

[0025] [Figure 1] FIG. 1 is a side view schematically illustrating the shovel of the first embodiment. [Figure 2] FIG. 2 is a plan view schematically illustrating the shovel. [Figure 3] FIG. 3 is a diagram illustrating the electrical configuration and power transmission paths of the shovel. [Figure 4] FIG. 4 is a diagram illustrating a virtual coordinate system. [Figure 5] FIG. 5 is a flowchart illustrating the processing procedure of the avoidance control of the first embodiment. [Figure 6] FIG. 6 is a diagram schematically illustrating an avoidance map. [Figure 7] FIG. 7 is a flowchart illustrating the processing procedure of the avoidance control of the third embodiment. [Mode for Carrying Out the Invention]

[0026] <First Embodiment> Hereinafter, the first embodiment of the drive system for a work machine, the work machine, the control device for a work machine, the control method for a work machine, and the control program for a work machine will be described by taking a construction machine as an example. Note that in the drawings, components may be illustrated in an enlarged manner for ease of understanding. Further, the dimensional ratios of the components may differ from actual ones or those in other drawings.

[0027] <Overall Configuration> As shown in Figure 1, the excavator 10, a construction machine, comprises a lower body 13 and an upper body 14. The upper body 14 is located on the opposite side of the lower body 13 from the ground G. In this embodiment, the direction in which the upper body 14 is located, as viewed from the lower body 13, is the upward direction, and the opposite direction is the downward direction. Furthermore, a specific direction perpendicular to the upward direction is the forward direction, and the opposite direction is the backward direction. In addition, as shown in Figure 2, one of the directions perpendicular to both the upward and forward directions is the left direction, and the other is the right direction. The forward and backward directions are sometimes collectively referred to as the X direction. The left and right directions are sometimes collectively referred to as the Y direction. The upward and downward directions are sometimes collectively referred to as the Z direction.

[0028] As shown in Figure 1, the lower body 13 and the upper body 14 constitute the vehicle body 15. The lower body 13 is, for example, rectangular parallelepiped. The upper body 14 is, for example, rectangular parallelepiped. The interior of the upper body 14 is a hollow storage space. The storage space houses various equipment for operating the excavator 10. Although not shown in the figure, the upper body 14 includes a cabin in which the worker sits. The upper body 14 is sometimes referred to as the upper slewing body.

[0029] As shown in Figure 1, the excavator 10 is equipped with a slewing bearing 18. The slewing bearing 18 is located between the lower body 13 and the upper body 14. In Figure 1, the vertical width of the slewing bearing 18 is exaggerated and shown as large with respect to the Z direction. As shown in Figure 2, the slewing bearing 18 comprises an annular inner ring 18A, an annular outer ring 18B, and a plurality of rolling elements. In Figure 2, the rolling elements are not shown. The outer diameter of the inner ring 18A is smaller than the inner diameter of the outer ring 18B. The slewing axis 10J, which is the central axis of the inner ring 18A, approximately coincides with the central axis of the outer ring 18B. The slewing axis 10J extends vertically across the vehicle body 15, i.e., in the Z direction. As shown in Figure 1, the slewing axis 10J passes vertically through both the upper body 14 and the lower body 13. The plurality of rolling elements are located between the inner ring 18A and the outer ring 18B. Multiple rolling elements support the inner ring 18A and the outer ring 18B so that they can rotate relative to each other. As a result, the outer ring 18B is rotatable relative to the inner ring 18A about the pivot axis 10J. The inner ring 18A is fixed to the lower body 13. The outer ring 18B is fixed to the upper body 14. That is, the upper body 14 is rotatable relative to the lower body 13 about the pivot axis 10J. It can also be said that the upper body 14 rotates relative to the lower body 13.

[0030] As shown in Figures 1 and 2, the lower body 13 is equipped with a pair of running gears 12. The pair of running gears 12 are located on both the left and right sides of the lower body 13. Both of the pair of running gears 12 are connected to the lower body 13. Each pair of running gears 12 includes a crawler for travel and an operating mechanism for rotating the crawler. The crawler is an endless belt shape. The crawler has openings on both the left and right sides. The underside of the crawler is in contact with the ground G. The excavator 10 moves as the crawler rotates. The running gears 12 and the lower body 13 are sometimes collectively referred to as the lower running gear.

[0031] As shown in Figure 1, the excavator 10 is equipped with a mounting wall 16. The mounting wall 16 is a component of the excavator 10 that is not included in the vehicle body 15. The mounting wall 16 is located on the front side relative to the upper body 14. The mounting wall 16 is located approximately in the center in the Y direction of the upper body 14. The mounting wall 16 is fixed to the front of the upper body 14. That is, the mounting wall 16 is attached to the vehicle body 15. The mounting wall 16 is, for example, a rectangular parallelepiped smaller than the upper body 14. The inside of the mounting wall 16 is hollow.

[0032] <Attachment> The excavator 10 is equipped with a drive system. As shown in Figure 1, the drive system is equipped with an attachment 20. The attachment 20 is equipped with a swing bracket 17, a boom 21, an arm 23, and a bucket 25.

[0033] As shown in Figures 1 and 2, the swing bracket 17 is positioned on the front side relative to the upper body 14. The swing bracket 17 comprises a first swing wall 17A and a second swing wall 17B. The first swing wall 17A is located on the upper surface of the mounting wall 16. The first swing wall 17A is, for example, disc-shaped. The first swing wall 17A is connected to the mounting wall 16. The first swing wall 17A is rotatable relative to the mounting wall 16 about a first axis 61J that extends vertically from the vehicle body 15. The first axis 61J is approximately parallel to the pivot axis 10J. The second swing wall 17B protrudes upward from the upper surface of the first swing wall 17A. The second swing wall 17B is, for example, rectangular plate-shaped. In this way, the swing bracket 17 is rotatably connected to the vehicle body 15 via the mounting wall 16. The swing bracket 17 corresponds to the first member.

[0034] As shown in Figure 1, the boom 21 is located on the front side relative to the upper body 14. The boom 21 is a long, plate-like or columnar shape. For example, the boom 21 is bent in the middle of its longitudinal direction. As shown in Figure 2, the first longitudinal end 21A of the boom 21 is aligned with the second swing wall 17B of the swing bracket 17 in the direction along the second axis 31J. The second axis 31J is a virtual axis that intersects the first axis 61J. More specifically, the second axis 31J is approximately perpendicular to the first axis 61J. The first end 21A of the boom 21 is rotatably connected to the second swing wall 17B. The boom 21 corresponds to the second member.

[0035] As shown in Figure 1, the arm 23 extends from the second end 21B of the boom 21, opposite to the first end 21A. The arm 23 is a long, plate-like or columnar shape. As shown in Figure 2, the longitudinal first end 23A of the arm 23 is aligned with the second end 21B of the boom 21 in the direction along the third axis 41J. The third axis 41J is a virtual axis approximately parallel to the second axis 31J. The first end 23A of the arm 23 is rotatably connected to the second end 21B of the boom 21.

[0036] As shown in Figure 1, the bucket 25 is located near the second end 23B of the arm 23, opposite to the first end 23A. The bucket 25 comprises a bucket body 26, a plurality of claws 27, and a bucket connecting wall 28. The bucket body 26 is box-shaped. That is, as shown in Figure 2, the bucket body 26 has an opening 26A. The claws 27 protrude from one side of the rectangular opening edge of the bucket body 26. The bucket connecting wall 28 protrudes from the outer wall of the bucket body 26, on the opposite side of the opening 26A from the claws 27. As shown in Figure 2, the bucket connecting wall 28 is aligned with the second end 23B of the arm 23 in the direction along the fourth axis 51J. The fourth axis 51J is a virtual axis that is substantially parallel to both the second axis 31J and the third axis 41J. The bucket connecting wall 28 is rotatably connected to the second end 23B of the arm 23. Bucket 25 is considered a working component.

[0037] <Drive Unit> As shown in Figure 3, the drive system of the excavator 10 includes a drive unit 30. The drive unit 30 is a set of devices for driving the attachment 20. The drive unit 30 includes a first drive device 61, a second drive device 31, a third drive device 41, and a fourth drive device 51. The drive unit 30 also includes a first inverter 65, a second inverter 35, a third inverter 45, a fourth inverter 55, and a battery 19. Although not shown in the figure, the first inverter 65, the second inverter 35, the third inverter 45, the fourth inverter 55, and the battery 19 are housed in the upper body 14.

[0038] As shown in Figure 1, the first drive unit 61 is housed in the mounting wall 16. As shown in Figure 3, the first drive unit 61 comprises a first electric motor 62 and a first reduction gear 63. The first electric motor 62 is a three-phase AC motor. The first electric motor 62 is electrically connected to the battery 19 via a first inverter 65. The first electric motor 62 comprises a housing 62A and an output shaft 62B that is rotatable relative to the housing 62A. The housing 62A is mounted on the mounting wall 16. The output shaft 62B protrudes from the inside to the outside of the housing 62A. The output shaft 62B is cylindrical. The output shaft 62B is rotatable relative to the housing 62A about its own central axis, the first axis 61J. That is, the output shaft 62B outputs torque about the first axis 61J. The output shaft 62B is rotatable 360 ​​degrees in both forward and reverse directions about the first axis 61J.

[0039] As shown in Figure 3, the first reduction gear 63 comprises a housing 63A, a reduction mechanism 63B, and an output member 63C. The housing 63A is fixed to the housing 63A of the first electric motor 62. The reduction mechanism 63B is located inside the housing 63A. Torque is input to the reduction mechanism 63B from the output shaft 62B of the first electric motor 62. The reduction mechanism 63B amplifies the torque from the first electric motor 62 at a predetermined ratio and outputs it to the output member 63C. The reduction mechanism 63B is, for example, an eccentric oscillating gear type or a planetary gear type. The output member 63C is cylindrical. The central axis of the output member 63C is approximately coincident with the first axis 61J. The output member 63C is rotatable relative to the housing 63A. The output member 63C rotates about the first axis 61J in accordance with the rotation of the output shaft 62B of the first electric motor 62. The output member 63C is attached to the first swing wall 17A of the swing bracket 17. That is, the output member 63C inputs torque to the swing bracket 17 around the first axis 61J. The swing bracket 17 receives this torque and rotates around the first axis 61J. In other words, the first drive device 61 is an electrically powered device that drives the swing bracket 17 using the first electric motor 62 as the drive source.

[0040] As shown in Figure 2, the second drive unit 31 is located between the second swing wall 17B of the swing bracket 17 and the first end 21A of the boom 21. The configuration of the second drive unit 31 is basically the same as that of the first drive unit 61, except for details such as dimensions, reduction ratio, and output. Therefore, the configuration of the second drive unit 31 will be briefly described below.

[0041] As shown in Figure 3, the second drive unit 31 comprises a second electric motor 32 and a second reduction gear 33. The second electric motor 32 is electrically connected to the battery 19 via a second inverter 35. The housing 32A of the second electric motor 32 is attached to the second swing wall 17B of the swing bracket 17. The output shaft 32B of the second electric motor 32 outputs torque around its own central axis, the second axis 31J. As shown in Figure 2, the second axis 31J passes through both the second swing wall 17B of the swing bracket 17 and the first end 21A of the boom 21. The output member 33C of the second reduction gear 33 is attached to the first end 21A of the boom 21. As shown in Figure 3, the output member 33C outputs torque around the second axis 31J. The boom 21 rotates around the second axis 31J in response to the torque from the output member 33C. Furthermore, the functions of the housing 33A and reduction mechanism 33B of the second reduction gear 33 are the same as those of the housing 63A and reduction mechanism 63B of the first reduction gear 63. In other words, the second drive unit 31 is an electrically powered device that drives the boom 21 using the second electric motor 32 as the drive source.

[0042] As shown in Figure 2, the third drive unit 41 is located between the second end 21B of the boom 21 and the first end 23A of the arm 23. The configuration of the third drive unit 41 is basically the same as that of the first drive unit 61, except for details such as dimensions, reduction ratio, and output. Therefore, the configuration of the third drive unit 41 will be briefly described below.

[0043] As shown in Figure 3, the third drive unit 41 comprises a third electric motor 42 and a third reduction gear 43. The third electric motor 42 is electrically connected to the battery 19 via a third inverter 45. The housing 42A of the third electric motor 42 is attached to the second end 21B of the boom 21. The output shaft 42B of the third electric motor 42 outputs torque around its own central axis, the third axis 41J. As shown in Figure 2, the third axis 41J passes through both the second end 21B of the boom 21 and the first end 23A of the arm 23. The output member 43C of the third reduction gear 43 is attached to the first end 23A of the arm 23. As shown in Figure 3, the output member 43C outputs torque around the third axis 41J. The arm 23 rotates around the third axis 41J in response to the torque from the output member 43C. Furthermore, the functions of the housing 43A and reduction mechanism 43B of the third reduction gear 43 are the same as those of the housing 63A and reduction mechanism 63B of the first reduction gear 63. In other words, the third drive unit 41 is an electrically powered device that uses the third electric motor 42 as a drive source to drive the arm 23.

[0044] As shown in Figure 2, the fourth drive unit 51 is located between the second end 23B of the arm 23 and the bucket connecting wall 28 of the bucket 25. The configuration of the fourth drive unit 51 is basically the same as that of the first drive unit 61, except for details such as dimensions, reduction ratio, and output. Therefore, the configuration of the fourth drive unit 51 will be briefly described below.

[0045] As shown in Figure 3, the fourth drive unit 51 comprises a fourth electric motor 52 and a fourth reduction gear 53. The fourth electric motor 52 is electrically connected to the battery 19 via a fourth inverter 55. The housing 52A of the fourth electric motor 52 is attached to the second end 23B of the arm 23. The output shaft 52B of the fourth electric motor 52 outputs torque around its own central axis, the fourth axis 51J. As shown in Figure 2, the fourth axis 51J passes through both the second end 23B of the arm 23 and the bucket connecting wall 28. The output member 53C of the fourth reduction gear 53 is attached to the bucket connecting wall 28. As shown in Figure 3, the output member 53C outputs torque around the fourth axis 51J. The bucket 25 rotates around the fourth axis 51J in response to the torque from the output member 53C. Furthermore, the functions of the housing 53A and reduction mechanism 53B of the fourth reduction gear 53 are the same as those of the housing 63A and reduction mechanism 63B of the first reduction gear 63. In other words, the fourth drive unit 51 is an electrically powered device that uses the fourth electric motor 52 as a drive source to drive the bucket 25.

[0046] As shown in Figure 3, the excavator 10 is equipped with a fifth drive unit 71 and a fifth inverter 75. The fifth drive unit 71 and the fifth inverter 75 are housed in the upper body 14. The configuration of the fifth drive unit 71 is basically the same as that of the first drive unit 61, except for details such as dimensions, reduction ratio, and output. Therefore, the configuration of the fifth drive unit 71 will be briefly described below.

[0047] As shown in Figure 3, the fifth drive unit 71 comprises a fifth electric motor 72 and a fifth reduction gear 73. The fifth electric motor 72 is electrically connected to the battery 19 via a fifth inverter 75. The housing 72A of the fifth electric motor 72 is attached to the upper body 14. The output shaft 72B of the fifth electric motor 72 outputs torque around its own central axis, the fifth axis 71J. Multiple teeth are formed on the output member 73C of the fifth reduction gear 73. These teeth mesh with the teeth formed on the inner ring 18A of the slewing bearing 18. The output member 73C outputs torque coaxial with the fifth electric motor 72. In response to this torque, the upper body 14 rotates with respect to the inner ring 18A and, consequently, the lower body 13, together with the housing 72A of the fifth electric motor 72. In other words, the fifth drive unit 71 causes the upper body 14 to rotate relative to the lower body 13. Furthermore, the functions of the housing 73A and reduction mechanism 73B of the fifth reduction gear 73 are the same as those of the housing 63A and reduction mechanism 63B of the first reduction gear 63.

[0048] <Sensor> As shown in Figure 3, the drive system of the excavator 10 includes a first sensor 68, a second sensor 38, a third sensor 48, and a fourth sensor 58. The first sensor 68 detects information regarding the angular position of the first electric motor 62 as first angular information 68S. The angular position of the first electric motor 62 is, strictly speaking, the angular position of the output shaft 62B of the first electric motor 62. For the other electric motors, the output shaft is omitted from the description of the angular position. The second sensor 38 detects information regarding the angular position of the second electric motor 32 as second angular information 38S. The third sensor 48 detects information regarding the angular position of the third electric motor 42 as third angular information 48S. The fourth sensor 58 detects information regarding the angular position of the fourth electric motor 52 as fourth angular information 58S. Each angular information represents an absolute angle. For example, the first angle information 68S indicates the angular position of the first electric motor 62 within a range of "0 degrees to 360 degrees," with a predetermined position set as "0 degrees." Each sensor repeatedly transmits the information it has detected to the control device 100, which will be described later.

[0049] Although not shown in the diagram, the excavator 10 is equipped with various sensors necessary for its operation, in addition to the sensors mentioned above. For example, the excavator 10 is equipped with sensors that detect the current flowing through each of the electric motors 32, 42, 52, 62, and 72, and a sensor that detects the temperature of the battery 19. In addition, the excavator 10 is equipped with an operating device 90 that is operated by the operator. The operating device 90 is located in the cabin. The operating device 90 repeatedly transmits an operation signal 90S in response to the operator's operation to the control device 100, which will be described later.

[0050] <Control device> As shown in Figure 3, the drive system of the excavator 10 includes a control device 100. The control device 100 is a computer equipped with a processing circuit. The processing circuit includes a CPU 101 and a memory 102. The memory 102 includes three types: RAM, ROM, and electrically rewritable nonvolatile memory. In this embodiment, these three types are collectively referred to as memory 102. The memory 102 pre-stores various control programs 102A that describe the processing to be executed by the CPU 101. The memory 102 pre-stores various data 102B necessary for the CPU 101 to execute the control programs 102A. The processing circuit includes a communication circuit for wireless communication with the outside.

[0051] Furthermore, the CPU 101 can receive first angle information 68S transmitted from the first sensor 68. The CPU 101 can receive second angle information 38S transmitted from the second sensor 38. The CPU 101 can receive third angle information 48S transmitted from the third sensor 48. The CPU 101 can receive fourth angle information 58S transmitted from the fourth sensor 58. The CPU 101 can receive operation signals 90S from the operation device 90.

[0052] The CPU 101 converts the first angle information 68S received from the first sensor 68 into the angular position of the swing bracket 17. Specifically, the CPU 101 calculates the actual angle, which is the actual angular position of the first electric motor 62, based on the first angle information 68S. Furthermore, the CPU 101 calculates the angular position of the swing bracket 17 from a predetermined first position based on the actual angle of the first electric motor 62, taking into account the reduction ratio of the first reduction gear 63, etc. For example, the memory 102 has prior knowledge of the actual angle of the first electric motor 62 when the swing bracket 17 is in the first position. The CPU 101 sequentially stores the history of the amount and direction of rotation of the swing bracket 17 from the first position in the memory 102 in accordance with the rotation of the first electric motor 62, and calculates the first angular position, which is the angular position of the swing bracket 17, based on this history. An example of the first position is the angular position where both main surfaces of the plate-shaped second swing wall 17B of the swing bracket 17 are facing in the Y direction. Furthermore, as can be seen from the conversion of the actual angle of the first electric motor 62 to a first angular position, the first sensor 68 that detects the actual angle of the first electric motor 62 effectively detects the first angular position.

[0053] Similar to the case of the first electric motor 62, the CPU 101 converts the second angle information 38S received from the second sensor 38 from the actual angle of the second electric motor 32 to a second angular position related to the boom 21. The second angular position is the angular position of the boom 21 from a predetermined second position. The second position is defined when viewing the excavator 10 facing in the direction along the second axis 31J. An example of the second position is an angular position where both the first end 21A and the second end 21B of the boom 21 are positioned on a virtual straight line perpendicular to both the first axis 61J and the second axis 31J. In this example of the second position, the second end 21B of the boom 21 is positioned on the opposite side from the vehicle body 15, with the second axis 31J in between. The second position can also be said to be the angular position of the boom 21 relative to the swing bracket 17. Similar to the first sensor 68, the second sensor 38, which detects the actual angle of the second electric motor 32, effectively detects the second angular position.

[0054] The CPU 101 converts the third angle information 48S received from the third sensor 48 into a third angular position related to the arm 23, based on the actual angle of the third electric motor 42, similar to the case of each electric motor 32 and 62 described above. The third angular position is the angular position of the arm 23 from a predetermined third position. The third position is defined when viewing the excavator 10 facing in the direction along the third axis 41J. An example of the third position is the angular position where both the first end 23A and the second end 23B of the arm 23 are positioned on a virtual axis passing through the second axis 31J and the third axis 41J. In this example of the third position, the second end 23B of the arm 23 is positioned on the opposite side of the third axis 41J from the second axis 31J. The third angular position can also be said to be the angular position of the arm 23 relative to the boom 21. The third sensor 48, which detects the actual angle of the third electric motor 42, effectively detects the third angular position.

[0055] The CPU 101 converts the fourth angle information 58S received from the fourth sensor 58 into a fourth angular position relative to the bucket 25, based on the actual angle of the fourth electric motor 52, similar to the cases of the electric motors 32, 42, and 62 described above. The fourth angular position is the angular position of the bucket 25 from a predetermined fourth position. The fourth position is defined by viewing the excavator 10 while facing in the direction along the fourth axis 51J. An example of the fourth position is the angular position where the claws 27 of the bucket 25 are positioned on a virtual axis passing through the third axis 41J and the fourth axis 51J. In this example of the fourth position, the claws 27 of the bucket 25 are positioned on the opposite side of the fourth axis 51J from the third axis 41J. The fourth angular position can also be said to be the angular position of the bucket 25 relative to the arm 23. The fourth sensor 58, which detects the actual angle of the fourth electric motor 52, effectively detects the fourth angular position.

[0056] The CPU 101 controls various parts of the excavator 10, such as the attachment 20. An example of a control target is the drive unit 30. Specifically, the CPU 101 controls the first electric motor 62 of the first drive unit 61, the second electric motor 32 of the second drive unit 31, the third electric motor 42 of the third drive unit 41, the fourth electric motor 52 of the fourth drive unit 51, and the fifth electric motor 72 of the fifth drive unit 71. When the CPU 101 controls the first electric motor 62, it effectively controls the first inverter 65. Similarly, when the CPU 101 controls the second electric motor 32, it effectively controls the second inverter 35. Similarly, when the CPU 101 controls the third electric motor 42, it effectively controls the third inverter 45. Similarly, when the CPU 101 controls the fourth electric motor 52, it effectively controls the fourth inverter 55. Similarly, when the CPU 101 controls the fifth electric motor 72, it essentially controls the fifth inverter 75. Furthermore, when the CPU 101 controls each of the electric motors 32, 42, 52, 62, and 72, it refers to the angular position of the component that each electric motor 32, 42, 52, 62, and 72 drives. For example, when the CPU 101 controls the first electric motor 62, it refers to the first angular position related to the swing bracket 17.

[0057] The following describes the various controls implemented by the CPU 101 when it executes the control program 102A. The CPU 101 performs drive control. In drive control, the CPU 101 controls the drive unit 30 to operate the attachment 20. Specifically, in drive control, the CPU 101 operates one or more of the multiple electric motors 32, 42, 52, 62, 72 in the drive unit 30 in response to the operation signal 90S from the operating device 90. That is, while drive control is being performed, one or more electric motors 32, 42, 52, 62, 72 are operating. As mentioned above, each electric motor 32, 42, 52, 62, 72 can rotate 360 ​​degrees in both forward and reverse directions. Due to this wide range of motion, the attachment 20 may come close to the vehicle body 15 when the CPU 101 performs drive control. For example, the dashed line 21X in Figure 1 and the dashed line 21Y in Figure 2 show examples of the boom 21 coming close to the vehicle body 15.

[0058] The CPU 101 performs avoidance control while drive control is being executed. Avoidance control is intended to avoid interference between the attachment 20 and the vehicle body 15. As data necessary for the CPU 101 to perform avoidance control, memory 102 pre-stores positional relationship information that shows the correspondence between the first angular position of the swing bracket 17, the second angular position of the boom 21, and the positional relationship between the vehicle body 15 and the attachment 20. The positional relationship information stored in memory 102 includes model information that simulates the excavator 10 in the virtual coordinate system 80Q. As shown in Figure 4, the virtual coordinate system 80Q is a three-dimensional Cartesian coordinate system that defines each position around the excavator 10. The X, Y, and Z axes of the virtual coordinate system 80Q extend in the X, Y, and Z directions, respectively, which define the front, rear, left, right, up, and down directions of the excavator 10. Note that in Figure 4, only the two-dimensional plane composed of the X and Z axes of the three-dimensional virtual coordinate system 80Q is shown.

[0059] The model information includes vehicle body coordinate information, a first relational equation, and a second relational equation. The vehicle body coordinate information indicates the position coordinates of various parts of the vehicle body 15, which is positioned at a reference position in the virtual coordinate system 80Q. Specifically, the vehicle body coordinate information is obtained by dividing the outer surface of the vehicle body 15 into a grid of a predetermined area and assigning a representative coordinate value to each grid. An example of the above reference position is the position of the vehicle body 15 when the intersection point of the pivot axis 10J and the lower surface of the upper body 14 is positioned at the origin of the virtual coordinate system 80Q. However, the reference position is not limited to this example and may be set in advance at an appropriate position. In other words, the orientation and reference point of the vehicle body 15 in the virtual coordinate system 80Q can be set as appropriate.

[0060] The first relational expression represents the relationship between the first coordinate information, which indicates the position coordinates of various points on the swing bracket 17 when the vehicle body 15 is positioned at a reference position, and the first angular position of the swing bracket 17. Here, the first angular position can change in various ways during the execution of drive control. The first relational expression shows the position coordinates of the swing bracket 17 at each of the first angular positions when the first angular position changes in various ways due to the execution of drive control. The first coordinate information, like the vehicle body coordinate information, is represented by dividing the outer surface of the swing bracket 17 into a grid of a predetermined area and expressing it as a coordinate value representing each grid.

[0061] The second relational equation represents the relationship between the second coordinate information, which indicates the position coordinates of various parts of the boom 21 when the vehicle body 15 is positioned at the reference position, and the first angular position of the swing bracket 17 and the second angular position of the boom 21. In other words, the second relational equation shows the position coordinates of the boom 21 for each combination of the first and second angular positions when the first and second angular positions change in various ways. The second coordinate information, like the first coordinate information, is represented by dividing the outer surface of the boom 21 into a grid of predetermined areas and expressing the coordinate values ​​that represent each grid.

[0062] <Processing procedure for avoidance control> When the CPU 101 starts drive control in response to the operation signal 90S, it simultaneously starts avoidance control. If the CPU 101 terminates drive control while executing avoidance control, it terminates the avoidance control at that point. In other words, the situation in which the CPU 101 is executing avoidance control is while the attachment 20 is operating.

[0063] As shown in Figure 5, in the avoidance control, the CPU 101 first performs the process in step S10. In step S10, the CPU 101 performs an acquisition process. In step S10, the CPU 101 acquires the angle information of the swing bracket 17 and the boom 21. Specifically, the CPU 101 acquires the latest first angle position of the swing bracket 17 and the latest second angle position of the boom 21. Once the CPU 101 has acquired the first and second angle positions, it terminates the process in step S10. Then, the CPU 101 proceeds to step S20.

[0064] In step S20, the CPU 101 performs calculation processing. In step S20, the CPU 101 calculates the positional relationship between the vehicle body 15 and the attachment 20 by applying the first and second angular positions acquired in the acquisition process to the positional relationship information stored in memory 102. Specifically, the CPU 101 calculates first coordinate information indicating the positional information of each part of the swing bracket 17 by applying the first angular position to the first relational expression of the model information included in the positional relationship information. The CPU 101 also calculates second coordinate information indicating the positional coordinates of each part of the boom 21 by applying the first and second angular positions to the second relational expression of the model information included in the positional relationship information. Then, based on the calculated first and second coordinate information and the vehicle body coordinate information indicating the positional coordinates of each part of the vehicle body 15, the CPU 101 calculates the shortest distance between the attachment 20 and the vehicle body 15 as the positional relationship. Note that the attachment 20 referred to here is limited to the swing bracket 17 and the boom 21. In other words, the shortest distance calculated by the CPU 101 is the point on the outer surface of the swing bracket 17 and boom 21 that is closest to the vehicle body 15. Once the CPU 101 has calculated the shortest distance, it terminates the process in step S20. Then, the CPU 101 proceeds to step S30.

[0065] In step S30, the CPU 101 determines whether the shortest distance between the attachment 20 and the vehicle body 15 is less than a predetermined value. For example, the predetermined value is determined in advance by experiment or simulation as the interval at which the attachment 20 does not interfere with the vehicle body 15 even if there is some error in the stopping timing of the electric motor. The predetermined value is, for example, several tens of centimeters. If it is determined that the shortest distance is greater than or equal to the predetermined value (step S30: NO), the CPU 101 proceeds to step S10 and repeats the processing of steps S10 to S30. On the other hand, if it is determined that the shortest distance is less than the predetermined value (step S30: YES), the CPU 101 proceeds to step S40.

[0066] In step S40, the CPU 101 performs corrective processing. Since it has already been determined in step S30 that the shortest distance between the attachment 20 and the vehicle body 15 is less than a predetermined value, the CPU 101 takes measures to avoid interference between the attachment 20 and the vehicle body 15 in the corrective processing. In this embodiment, the CPU 101 controls the first drive unit 61 of the drive unit 30 to stop the operation of the swing bracket 17, and controls the second drive unit 31 of the drive unit 30 to stop the operation of the boom 21. Once the operation of the swing bracket 17 and the boom 21 has stopped, the CPU 101 terminates the processing in step S40.

[0067] <Operation of the First Embodiment> The operation of the attachment 20 shown in Figures 1 and 2 will now be explained. In the attachment 20, when the output shaft 62B of the first electric motor 62 rotates, the output member 63C of the first reduction gear 63 rotates together with the output shaft 62B. The rotational speed of the output member 63C is reduced by a predetermined ratio to the rotational speed of the output shaft 62B of the first electric motor 62. In other words, the first reduction gear 63 amplifies and outputs the torque output by the output shaft 62B of the first electric motor 62. When the output member 63C rotates, the first swing wall 17A and the second swing wall 17B of the swing bracket 17 rotate. Then, the boom 21, which is connected to the second swing wall 17B via the second drive unit 31, rotates. Through this series of force transmissions, the boom 21 swings left and right around the first axis 61J.

[0068] Furthermore, in the attachment 20, when the output shaft 32B of the second electric motor 32 rotates, the output member 33C of the second reduction gear 33 rotates together with the output shaft 32B. The rotational speed of the output member 33C is reduced by a predetermined ratio to the rotational speed of the output shaft 32B of the second electric motor 32. In other words, the second reduction gear 33 amplifies and outputs the torque output by the output shaft 32B of the second electric motor 32. When the output member 33C rotates, the boom 21 rotates. Through this series of force transmissions, the boom 21 rotates around the second axis 31J.

[0069] <Effects of the First Embodiment> (1-1) In this embodiment, when the swing bracket 17 and boom 21 are driven by electric motors 32 and 62, the range of motion of the swing bracket 17 and boom 21 is wider than when they are driven by hydraulics. As a result, there is a problem that the swing bracket 17 and boom 21 are more likely to interfere with the vehicle body 15. In particular, when the rotation of the swing bracket 17 and the rotation of the boom 21 occur simultaneously, interference with the vehicle body 15 becomes even more likely.

[0070] Therefore, in this embodiment, the shortest distance between the attachment 20 and the vehicle body 15 is calculated based on first coordinate information indicating the position of the swing bracket 17, second coordinate information indicating the position coordinate of the boom 21, and vehicle body coordinate information indicating the position coordinate of the vehicle body 15. If the calculated shortest distance is less than a predetermined value, measures are taken to avoid interference between the swing bracket 17 and boom 21 and the vehicle body 15. This prevents the swing bracket 17 and boom 21 from colliding with the vehicle body 15.

[0071] (1-2) In step S30 of the avoidance control, it is determined whether the shortest distance between the swing bracket 17 and the vehicle body 15 is less than a predetermined value. The swing bracket 17 and the boom 21 are attachments 20 that are closer to the vehicle body 15 than the arm 23 and bucket 25 and are therefore more likely to collide with the vehicle body 15. Therefore, if the shortest distance is less than a predetermined value, taking measures to avoid interference between the attachment 20 and the vehicle body 15 can reliably prevent a collision between the attachment 20 and the vehicle body 15.

[0072] (1-3) In step S40 of the avoidance control, the CPU 101 controls the drive units 31 and 61 to stop the operation of the swing bracket 17 and boom 21. Therefore, as a measure to avoid interference between the attachment 20 and the vehicle body 15, it is possible to forcibly avoid a collision between the attachment 20 and the vehicle body 15, compared to simply issuing a warning.

[0073] (1-4) In the configuration of this embodiment, the positional relationship information stored in the memory 102 includes model information that simulates the excavator 10 in a virtual coordinate system 80Q. The CPU 101 then calculates first coordinate information indicating the position coordinates of various parts of the swing bracket 17 by applying the first angular position of the swing bracket 17 to the first relational expression included in the model information. The CPU 101 also calculates second coordinate information indicating the position coordinates of various parts of the boom 21 by applying the first angular position and the second angular position of the boom 21 to the second relational expression included in the model information. Furthermore, the CPU 101 calculates the shortest distance between the attachment 20 and the vehicle body 15 based on the calculated first and second coordinate information and vehicle body coordinate information indicating the position coordinates of various parts of the vehicle body 15. This makes it possible to calculate the shortest distance accurately and easily.

[0074] <Second Embodiment> The following describes a second embodiment of the drive system for the work machine, the work machine, the control device for the work machine, the control method for the work machine, and the control program for the work machine. In this embodiment, the content of the model information and the content of the associated avoidance control differ from the first embodiment. Aside from these points, the content of the second embodiment is basically the same as that of the first embodiment. The following description of the second embodiment will mainly focus on the parts that differ from the first embodiment, and parts that overlap with the content of the first embodiment will be omitted or simplified as appropriate.

[0075] In this embodiment, the model information stored in memory 102 includes, in addition to the vehicle body coordinate information, the first relational expression, and the second relational expression, the third relational expression and the fourth relational expression. The vehicle body coordinate information, the first relational expression, and the second relational expression are as described in the first embodiment. The third relational expression represents the relationship between the third coordinate information, which indicates the position coordinates of each part of the arm 23, and the first angular position, the second angular position, and the third angular position. The third angular position is the angular position of the arm 23, as has already been described. The third relational expression is similar to the first and second relational expressions, but is determined from the correspondence with the combination of three angular positions for the outer surface of the arm 23. The fourth relational expression represents the relationship between the fourth coordinate information, which indicates the position coordinates of each part of the bucket 25, and the first angular position, the second angular position, the third angular position, and the fourth angular position. The fourth angular position is the angular position of the bucket 25, as has already been described. The fourth relation is similar to the first relation and others, but is determined by the correspondence with the combination of four angular positions on the outer surface of the bucket 25. The model information described above constitutes information that shows the correspondence between the first, second, third, and fourth angular positions and the positional relationship between the vehicle body 15 and the attachment 20.

[0076] In the avoidance control of this embodiment, the CPU 101 performs the following processing. In step S10 shown in Figure 5, the CPU 101 acquires the first angular position of the swing bracket 17, the second angular position of the boom 21, the third angular position of the arm 23, and the fourth angular position of the bucket 25. Then, in step S20, the CPU 101 applies the first, second, third, and fourth angular positions acquired in the acquisition process to the positional relationship information stored in memory 102. As a result, the CPU 101 calculates the positional relationship between the vehicle body 15 and the attachment 20. Specifically, the CPU 101 calculates first coordinate information indicating the positional information of each part of the swing bracket 17 by applying the first angular position to the first relational expression of the model information. The CPU 101 calculates second coordinate information indicating the positional coordinates of each part of the boom 21 by applying the first and second angular positions to the second relational expression of the model information. The CPU 101 calculates third coordinate information, which indicates the position coordinates of various parts of the arm 23, by applying the first, second, and third angular positions to the third relational expression of the model information. The CPU 101 calculates fourth coordinate information, which indicates the position coordinates of various parts of the bucket 25, by applying the first, second, third, and fourth angular positions to the fourth relational expression of the model information. Then, based on the calculated first, second, third, and fourth coordinate information and the vehicle body coordinate information, which indicates the position coordinates of various parts of the vehicle body 15, the CPU 101 calculates the shortest distance between the attachment 20 and the vehicle body 15 as a positional relationship. In this case, the shortest distance is calculated based on the point on the outer surface of the swing bracket 17, boom 21, arm 23, and bucket 25 that is closest to the vehicle body 15. Once the CPU 101 has calculated the shortest distance, it proceeds to step S30. The CPU 101 then determines whether the shortest distance between the attachment 20 and the vehicle body 15 is less than a predetermined value. If it determines that the shortest distance is less than the predetermined value (step S30: YES), the CPU 101 proceeds to step S40.

[0077] In step S40, the CPU 101 takes measures to avoid interference between the attachment 20 and the vehicle body 15. In this embodiment, the CPU 101 controls the first drive unit 61 to stop the movement of the swing bracket 17 and the second drive unit 31 to stop the movement of the boom 21. Furthermore, the CPU 101 controls the third drive unit 41 to stop the movement of the arm 23 and the fourth drive unit 51 to stop the movement of the bucket 25. Once the movement of the swing bracket 17, boom 21, arm 23, and bucket 25 has stopped, the CPU 101 terminates the process of step S40.

[0078] <Effects of the second embodiment> The configuration of this embodiment provides the same effects as (1-1) to (1-4). Furthermore, the configuration of this embodiment also provides the following effects.

[0079] (2-1) In this embodiment, in addition to the first coordinate information, second coordinate information, and vehicle body coordinate information, the shortest distance between the attachment 20 and the vehicle body 15 is calculated based on third coordinate information indicating the position coordinate of the arm 23 and fourth coordinate information indicating the position coordinate of the bucket 25. If the calculated shortest distance is less than a predetermined value, measures are taken to avoid interference between the attachment 20 and the vehicle body 15. That is, when taking measures to avoid interference, not only the positions of the swing bracket 17 and boom 21 but also the positions of the arm 23 and bucket 25 are taken into consideration. This makes it possible to more reliably prevent the attachment 20 from colliding with the vehicle body 15.

[0080] <Third Embodiment> The following describes a third embodiment of the drive system for the work machine, the work machine, the control device for the work machine, the control method for the work machine, and the control program for the work machine. In this embodiment, a different type of positional relationship information is used compared to the model information. Consequently, the content of the avoidance control in this embodiment differs from that of the first embodiment. Aside from these points, the content of the third embodiment is basically the same as that of the first embodiment. In the following, the parts of the third embodiment that differ from the first embodiment will be mainly described, and parts that overlap with the content of the first embodiment will be omitted or simplified as appropriate.

[0081] In this embodiment, the positional relationship information stored in memory 102 is the avoidance map 110. As shown in Figure 6, the avoidance map 110 is a graph showing the correspondence between a first angular position, which is the angular position of the swing bracket 17, a second angular position, which is the angular position of the boom 21, and an avoidance index value. Specifically, the avoidance map 110 defines an avoidance index value for each combination of the first angular position and the second angular position. The avoidance index value is an index value that indicates whether the shortest distance between the attachment 20 and the vehicle body 15 is less than a predetermined value. The avoidance index value takes one of two values: a first value indicating that the shortest distance is less than a predetermined value, or a second value indicating that the shortest distance is greater than or equal to a predetermined value. In the avoidance map 110, one of the first and second values ​​is set for each combination of the first and second angular positions. For example, in the avoidance map 110 shown in Figure 6, the first angular position is "0°" when both main surfaces of the second swing wall 17B of the swing bracket 17 are in the first position facing the Y direction. Also, in the avoidance map 110, the second angular position is "0°" when both the first end 21A and the second end 21B of the boom 21 are in the second position, which is located on a virtual straight line perpendicular to both the first axis 61J and the second axis 31J. Furthermore, in the avoidance map 110, the first value is set in the area without dots, and the second value is set in the area with dots. Note that the area where the first value is set and the area where the second value is set in the avoidance map 110 may change depending on the shape of the vehicle body 15, etc. The avoidance map 110 is created based on a simulation of a model that simulates an excavator 10. The attachments 20 targeted in this simulation are the swing bracket 17 and the boom 21. In other words, the avoidance map 110 of this embodiment targets the swing bracket 17 and the boom 21.

[0082] In the avoidance control of this embodiment, the CPU 101 performs the following processing. As shown in Figure 7, first in step S110, the CPU 101 acquires the first angular position of the swing bracket 17 and the second angular position of the boom 21 as an acquisition process. The content of this step S110 is the same as the content of step S10 in the first embodiment.

[0083] After step S110, the CPU 101 performs calculation processing in step S120. In step S120, the CPU 101 applies the first and second angular positions obtained in step S110 to the avoidance map 110 to calculate avoidance index values ​​corresponding to the first and second angular positions as positional relationships.

[0084] After step S120, in step S130, the CPU 101 determines whether the shortest distance between the attachment 20 and the vehicle body 15 is less than a predetermined value. If the avoidance index value calculated in step S120 is the second value, the CPU 101 determines that the shortest distance is greater than or equal to the predetermined value (step S130: NO). In this case, the CPU 101 returns to the process of step S110. On the other hand, if the avoidance index value calculated in step S120 is the first value, the CPU 101 determines that the shortest distance is less than the predetermined value (step S130: YES). In this case, the CPU 101 proceeds to step S140. The content of the process in step S140 is the same as the content of the process in step S40 of the first embodiment.

[0085] <Effects of the Third Embodiment> This embodiment provides the same effects as (1-2) and (1-3). Furthermore, the configuration of this embodiment also provides the following effects.

[0086] (3-1) In this embodiment, as in the first embodiment, collision between the swing bracket 17 and the boom 21 and the vehicle body 15 can be prevented. To achieve this, in this embodiment, an avoidance map 110 is prepared in advance, which defines avoidance index values ​​for each combination of the first and second angular positions. When using such an avoidance map 110, by simply applying the first and second angular positions to the avoidance map 110, it is immediately possible to determine whether the shortest distance between the attachment 20 and the vehicle body 15 is less than a predetermined value. Therefore, complex processing is not required to calculate the shortest distance, and the processing load on the CPU 101 can be reduced.

[0087] <Example of changes> Each of the above embodiments can be implemented with the following modifications. Each of the above embodiments and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0088] The positional relationship information stored in memory 102 is not limited to the example of the above embodiment. The positional relationship information only needs to show the correspondence between the angular positions of the members constituting the attachment 20 and the positional relationship between the vehicle body 15 and the attachment 20. For example, the positional relationship information may be a table in which corresponding index values ​​are pre-set for each combination of the first angular position, the second angular position, the third angular position, and the fourth angular position. In this case, the corresponding index values ​​can be set considering not only the swing bracket 17 and boom 21 of the attachment 20, but also the arm 23 and bucket 25.

[0089] The content of the acquisition and calculation processes in the avoidance control is not limited to the examples of each embodiment described above. The acquisition process only needs to acquire the angular position necessary for the calculation process, etc. The calculation process only needs to calculate the positional relationship between the vehicle body 15 and the attachment 20. For example, in the acquisition process, in addition to the first angular position of the swing bracket 17 and the second angular position of the boom 21, one of the third angular position of the arm 23 and the fourth angular position of the bucket 25 may be acquired. Then, in the calculation process, the positional relationship between the vehicle body 15 and the attachment 20 may be calculated from the correspondence between these three angular positions and the attitude of the attachment 20. Furthermore, in the acquisition and calculation processes, in addition to the first to fourth angular positions, processing may be performed using the angular positions of a fifth or more member rotatably connected to the working member.

[0090] The positional relationship information calculated in the calculation process is not limited to the shortest distance or avoidance indicator value; it can be any information that allows us to understand the shortest distance between the attachment 20 and the vehicle body 15. The acquisition process and calculation process should be configured in conjunction with the positional relationship information so that appropriate information can be calculated.

[0091] The content of the countermeasures in the avoidance control is not limited to the examples of each embodiment described above. The countermeasures only need to take measures to avoid interference between the attachment 20 and the vehicle body 15 based on the posture of the attachment 20. For example, in the first embodiment, the CPU 101 may control the drive unit 30 to stop the operation of either the swing bracket 17 or the boom 21. Furthermore, in addition to controlling the drive unit 30 to stop the operation of the swing bracket 17 and the boom 21, the CPU 101 may also control the drive unit 30 to stop the operation of at least one of the arm 23 and the bucket 25. Similarly, with respect to the second embodiment, instead of stopping the operation of all of the swing bracket 17, boom 21, arm 23, and bucket 25, the CPU 101 may stop the operation of one or more of them. The method of controlling the drive unit 30 in the countermeasures is not limited as long as interference between the attachment 20 and the vehicle body 15 can be avoided. For example, the CPU 101 may gradually reduce the operating speed of the attachment 20. Furthermore, the content of the corrective action is not limited to avoiding interference between the attachment 20 and the vehicle body 15 through the corrective action itself. For example, the content of the corrective action may be a process that prompts the operator to be aware of the possibility of interference between the attachment 20 and the vehicle body 15. Specifically, the CPU 101 may notify the operator of the possibility of interference between the attachment 20 and the vehicle body 15 using text, voice, lights, etc. Thus, the corrective action only needs to take some action that leads to avoiding interference between the attachment 20 and the vehicle body 15.

[0092] The predetermined value used as the criterion for determining whether the shortest distance between the attachment 20 and the vehicle body 15 is satisfactory may be changed according to the part of the vehicle body 15. For example, a first predetermined value may be set, which is a predetermined value for the upper body 14, and a second predetermined value may be set, which is a predetermined value for the lower traveling body consisting of the traveling device 12 and the lower body 13, and the first predetermined value and the second predetermined value may be set to different values ​​from each other.

[0093] In the above embodiment, the corrective action was performed on the condition that the shortest distance between the attachment 20 and the vehicle body 15 was less than a predetermined value. However, the conditions for executing the corrective action are not limited to this example. The necessity of executing the corrective action may be appropriately determined based on information obtained in the acquisition process, etc. Then, the corrective action may be performed as needed.

[0094] The configuration of the first drive unit 61 is not limited to the examples of the above embodiment. The first drive unit 61 may include an electric motor and only need to be able to drive the rotation of the swing bracket 17. For example, the first reduction gear 63 may be omitted from the first drive unit 61. The output shaft 62B of the first electric motor 62 may be treated as the output member of the first drive unit 61. Furthermore, the first drive unit 61 is not limited to outputting torque coaxial with the output shaft of the electric motor to the outside. For example, the first drive unit 61 may convert the rotational motion of the first electric motor 62 into linear motion and output it. The manner in which the swing bracket 17 is connected may be changed so that the swing bracket 17 can be rotationally driven around a specific axis of rotation by such linear motion. An example of a mechanism in the first drive unit 61 that converts rotational motion into linear motion is a so-called ball screw mechanism. Thus, the mechanism for driving the swing bracket 17 is not limited to the examples of the above embodiment. Furthermore, in accordance with the changes to the mechanism that drives the swing bracket 17, the configuration of connecting the swing bracket 17 to the vehicle body 15, and the configuration of the swing bracket 17 itself may be changed from the example of the above embodiment. The swing bracket 17 may be directly connected to the vehicle body 15. The swing bracket 17 only needs to be rotatably connected to the vehicle body 15 so that it can rotate about an axis extending vertically from the vehicle body 15.

[0095] Similar to the above-described examples of modifications to the first drive unit 61, the configuration of the second drive unit 31 is not limited to the examples of the above embodiments. The second drive unit 31 only needs to include an electric motor and be able to drive the rotation of the boom 21. The second reduction gear 33 may be eliminated from the second drive unit 31, or a mechanism for converting the rotational motion of the second electric motor 32 into linear motion may be provided.

[0096] Similar to the above-described examples of modifications to the first drive unit 61, the configuration of the third drive unit 41 is not limited to the examples of the above embodiments. The third drive unit 41 only needs to include an electric motor and be able to drive the rotation of the arm 23. The third reduction gear 43 may be eliminated from the third drive unit 41, or a mechanism for converting the rotational motion of the third electric motor 42 into linear motion may be provided.

[0097] Similar to the above-described examples of modifications to the first drive unit 61, the configuration of the fourth drive unit 51 is not limited to the examples of the above embodiments. The fourth drive unit 51 only needs to include an electric motor and be able to drive the rotation of the bucket 25. The fourth reduction gear 53 may be eliminated from the fourth drive unit 51, or a mechanism for converting the rotational motion of the fourth electric motor 52 into linear motion may be provided.

[0098] Similar to the above-described examples of modifications to the first drive unit 61, the configuration of the fifth drive unit 71 is not limited to the examples of the above embodiments. The fifth drive unit 71 only needs to include an electric motor and be able to drive the rotation of the inner ring 18A of the slewing bearing 18. The fifth reduction gear 73 may be eliminated from the fifth drive unit 71, or a mechanism may be provided to convert the rotational motion of the fifth electric motor 72 into linear motion.

[0099] The configuration of the attachment 20 is not limited to the examples of the above embodiments. The attachment 20 may have a first member rotatably connected to the vehicle body 15 and a second member rotatably connected to the first member. The attachment 20 may consist of only the first and second members, or it may be made up of five or more connected members.

[0100] The first and second members are not limited to the examples of the above embodiment. For example, the first member may be a boom 21 and the second member may be an arm 23. In this case, the swing bracket 17 may be omitted. In other words, the first member does not have to rotate relative to the vehicle body 15 about a first axis 61J that extends vertically from the vehicle body 15.

[0101] • The working member is not limited to the bucket 25. Appropriate devices, mechanisms, tools, etc. may be used as working members depending on the work. If a working member that does not require rotation is used, the fourth drive unit 51 may be abolished and the working member may be directly connected to the arm 23.

[0102] The arm 23 and bucket 25 are not mandatory. The bucket 25 may be omitted. If the bucket 25 is omitted, the fourth drive unit 51 may also be omitted accordingly. Alternatively, the arm 23 may be omitted, and the bucket 25 may be connected to the boom 21 without using the arm 23. If the arm 23 is omitted, the third drive unit 41 may also be omitted accordingly.

[0103] The configuration of the mounting wall 16 is not limited to the example of the above embodiment. For example, the shape of the mounting wall 16 may be other than a rectangular parallelepiped. The mounting wall 16 only needs to be able to connect the swing bracket 17 to the vehicle body 15. If the swing bracket 17 can be connected to the vehicle body 15 without using a wall section called the mounting wall 16, the mounting wall 16 may be omitted. In other words, the mounting wall 16 is not essential.

[0104] The configuration of the upper body 14 is not limited to the examples of the above embodiments. For example, the cabin may be eliminated from the upper body 14. The shape of the upper body 14 may be other than a rectangular parallelepiped. The upper body 14 only needs to be configured to fulfill the necessary functions, such as housing various pieces of equipment.

[0105] As shown in the above example of modification, the operating equipment 90 may be removed from the upper body 14 in conjunction with the removal of the cabin from the upper body 14. At the same time, the operating signal 90S for the drive unit 30 may be transmitted wirelessly from equipment outside the vehicle body 15. In other words, the equipment that transmits the operating signal 90S is not limited to equipment mounted on the vehicle body 15.

[0106] The overall configuration of the vehicle body 15 and, by extension, the excavator 10 is not limited to the example of the above embodiment. For example, the overall shape of the vehicle body 15 may be changed from the example of the above embodiment in conjunction with changing the shape of the upper body 14 as in the modified example above. It is sufficient that the excavator 10 as a whole is configured to perform the required work, such as excavation.

[0107] • The work machine is not limited to the excavator 10. The work machine may be any construction machine other than the excavator 10. Furthermore, the work machine is not limited to construction machines. Examples of work machines other than construction machines include machines used in forestry, quarrying, industrial waste treatment, and agriculture.

[0108] The processing circuit of the control device 100 may have any of the following configurations (a) to (c). (a) The processing circuit comprises one or more processors that perform various processes according to a computer program. The processor includes a CPU 101 and memory 102 such as RAM and ROM. Memory 102 stores program code or instructions configured to cause the CPU 101 to perform the processes. Memory 102, i.e., computer-readable media, includes any available media that can be accessed by a general-purpose or dedicated computer.

[0109] (b) The processing circuit comprises one or more dedicated hardware circuits that perform various processing tasks. Examples of dedicated hardware circuits include application-specific integrated circuits, i.e., ASICs or FPGAs.

[0110] (c) The processing circuit comprises a processor that executes a portion of the various processes according to a computer program, and a dedicated hardware circuit that executes the remaining parts of the various processes.

[0111] In the above embodiment, a structure composed of multiple objects may be integrated, or conversely, a structure composed of a single object may be divided into multiple objects. Whether or not the objects are integrated, the structure should be configured in a way that achieves the objective of the invention.

[0112] In the above embodiment, if multiple functions are provided in a distributed manner, some or all of those multiple functions may be consolidated and provided together. Conversely, if multiple functions are consolidated and provided together, some or all of those multiple functions may be distributed and provided together. Regardless of whether the functions are consolidated or distributed, it is sufficient that the device is configured to achieve the objective of the invention. [Explanation of symbols]

[0113] 10... Excavator 15... Vehicle body 17…Swing bracket 20... Attachments 21... Boom 23... Arm 25… Bucket 30…Drive unit 31...Second drive unit 31J…Second axis 32…Second electric motor 38...Second sensor 41...Third drive unit 41J…3rd axis 42…Third electric motor 48...Third sensor 51…Fourth drive unit 51J…4th axis 52…Fourth electric motor 58...Fourth sensor 61...First drive unit 61J…1st axis 62…First electric motor 68...First sensor 80Q…Virtual coordinate system 100...Control device 101…CPU 102...memory

Claims

1. An attachment having a first member rotatably connected to the body of a work machine, and a second member rotatably connected to the first member, A drive unit having a first drive device for driving the first member and a second drive device for driving the second member, A first sensor for detecting a first angular position, which is the angular position of the first member, A second sensor detects a second angular position, which is the angular position of the second member, The system includes a control device that performs drive control to control the drive unit, The control device is During the execution of the drive control, an acquisition process is performed to acquire the first angular position and the second angular position, Based on the first and second angular positions acquired in the acquisition process, the system performs a countermeasure process to take measures to avoid interference between the attachment and the vehicle body. A drive system for industrial machinery.

2. The control device is In the aforementioned corrective process, the first drive unit is controlled to stop the operation of the first member, and the second drive unit is controlled to stop the operation of the second member. A drive system for a work machine according to claim 1.

3. The control device is Positional relationship information indicating the correspondence between the first and second angular positions and the positional relationship between the vehicle body and the attachment is stored in advance. A calculation process is performed to calculate the positional relationship by applying the first angular position and the second angular position obtained in the acquisition process to the positional relationship information. The corrective action is executed if the positional relationship calculated in the calculation process indicates that the shortest distance between the attachment and the vehicle body is less than a predetermined value. A drive system for a work machine according to claim 1.

4. The positional relationship information represents the correspondence between the first angular position and the second angular position and an index value indicating whether or not the shortest distance is less than the predetermined value. In the calculation process, the control device calculates the index value as the positional relationship by applying the first angular position and the second angular position acquired in the acquisition process to the positional relationship information. A drive system for a work machine according to claim 3.

5. The positional relationship information includes model information that simulates the work machine in a virtual coordinate system. The aforementioned model information is, Vehicle body coordinate information indicating the position coordinates of various parts of the vehicle body placed at a predetermined reference position in the virtual coordinate system, A first relational expression that represents the relationship between the first coordinate information indicating the position coordinates of each part of the first member when the vehicle body is positioned at the aforementioned reference position, and the first angular position, The system includes second coordinate information indicating the position coordinates of each part of the second member when the vehicle body is positioned at the aforementioned reference position, and a second relational expression representing the relationship between the first angular position and the second angular position. In the calculation process, the control device calculates the first coordinate information by applying the first angular position to the first relational expression, and calculates the second coordinate information by applying the first and second angular positions to the second relational expression. Based on the calculated first and second coordinate information and the vehicle body coordinate information, the control device calculates the shortest distance as the positional relationship. A drive system for a work machine according to claim 3.

6. The first drive unit uses the first electric motor as its drive source, The second drive unit uses the second electric motor as its drive source. A drive system for a work machine according to claim 1.

7. The first member is a swing bracket that rotates about a first axis extending vertically along the vehicle body. The second member is a boom that rotates about a second axis that intersects the first axis. The drive system for the work machine according to claim 6.

8. The aforementioned attachment is, An arm is rotatably connected to the boom and rotates about a third axis parallel to the second axis, It has a working member that is rotatably connected to the arm and rotates about a fourth axis parallel to the second axis, The aforementioned drive unit is A third drive unit that uses a third electric motor as a drive source to drive the arm, It has a fourth drive unit that uses a fourth electric motor as a drive source to drive the work member, A third sensor detects a third angular position, which is the angular position of the arm, The system includes a fourth sensor that detects a fourth angular position, which is the angular position of the work member, The control device is Positional relationship information indicating the correspondence between the first, second, third, and fourth angular positions and the positional relationship between the vehicle body and the attachment is stored in advance. In the acquisition process described above, the first angular position, the second angular position, the third angular position, and the fourth angular position are acquired. A calculation process is performed to calculate the positional relationship by applying the first, second, third, and fourth angular positions obtained in the acquisition process to the positional relationship information. The corrective action is executed if the positional relationship calculated in the calculation process indicates that the distance between the attachment and the vehicle body is less than a predetermined value. A drive system for a work machine according to claim 7.

9. The car body and, An attachment having a first member rotatably connected to the vehicle body and a second member rotatably connected to the first member, A drive unit having a first drive device for driving the first member and a second drive device for driving the second member, A first sensor for detecting a first angular position, which is the angular position of the first member, A second sensor detects a second angular position, which is the angular position of the second member, The system includes a control device that performs drive control to control the drive unit, The control device is During the execution of the drive control, an acquisition process is performed to acquire the first angular position and the second angular position, Based on the first and second angular positions acquired in the acquisition process, the system performs a countermeasure process to take measures to avoid interference between the attachment and the vehicle body. Agricultural machinery.

10. An attachment having a first member rotatably connected to the vehicle body, and a second member rotatably connected to the first member, A drive unit having a first drive device for driving the first member and a second drive device for driving the second member, A first sensor for detecting a first angular position, which is the angular position of the first member, A second sensor detects a second angular position, which is the angular position of the second member, Applicable to work machines equipped with, An acquisition process to acquire the first angular position and the second angular position during the execution of drive control for controlling the drive unit, Based on the first and second angular positions acquired in the acquisition process, the system performs a countermeasure process to take measures to avoid interference between the attachment and the vehicle body. Control device for industrial machinery.

11. Positional relationship information indicating the correspondence between the first and second angular positions and the positional relationship between the vehicle body and the attachment is stored in advance. A calculation process is performed to calculate the positional relationship by applying the first angular position and the second angular position obtained in the acquisition process to the positional relationship information. The corrective action is executed if the positional relationship calculated in the calculation process indicates that the shortest distance between the attachment and the vehicle body is less than a predetermined value. A control device for a work machine according to claim 10.

12. The positional relationship information represents the correspondence between the first angular position and the second angular position and an index value indicating whether or not the shortest distance is less than the predetermined value. In the calculation process described above, the index value is calculated as the positional relationship by applying the first angular position and the second angular position acquired in the acquisition process described above to the positional relationship information. A control device for a work machine according to claim 11.

13. The positional relationship information includes model information that simulates the work machine in a virtual coordinate system. The aforementioned model information is, Vehicle body coordinate information indicating the position coordinates of various parts of the vehicle body placed at a predetermined reference position in the virtual coordinate system, A first relational expression that represents the relationship between the first coordinate information indicating the position coordinates of each part of the first member when the vehicle body is positioned at the aforementioned reference position, and the first angular position, The system includes second coordinate information indicating the position coordinates of each part of the second member when the vehicle body is positioned at the aforementioned reference position, and a second relational expression representing the relationship between the first angular position and the second angular position. In the calculation process described above, the first coordinate information is calculated by applying the first angular position to the first relational expression, and the second coordinate information is calculated by applying the first angular position and the second angular position to the second relational expression. Based on the calculated first and second coordinate information and the vehicle body coordinate information, the shortest distance is calculated as the positional relationship. A control device for a work machine according to claim 11.

14. An attachment having a first member rotatably connected to the vehicle body, and a second member rotatably connected to the first member, A drive unit having a first drive device for driving the first member and a second drive device for driving the second member, A first sensor for detecting a first angular position, which is the angular position of the first member, A second sensor detects a second angular position, which is the angular position of the second member, A control device applied to a work machine equipped with An acquisition process to acquire the first angular position and the second angular position during the execution of drive control for controlling the drive unit, Based on the first and second angular positions acquired in the acquisition process, the system performs a countermeasure process to take measures to avoid interference between the attachment and the vehicle body. A method for controlling industrial machinery.

15. An attachment having a first member rotatably connected to the vehicle body, and a second member rotatably connected to the first member, A drive unit having a first drive device for driving the first member and a second drive device for driving the second member, A first sensor for detecting a first angular position, which is the angular position of the first member, A second sensor detects a second angular position, which is the angular position of the second member, A control device applied to a work machine equipped with the following: An acquisition process to acquire the first angular position and the second angular position during the execution of drive control for controlling the drive unit, Based on the first and second angular positions acquired in the acquisition process, the system performs a countermeasure process to take measures to avoid interference between the attachment and the vehicle body. Control program for industrial machinery.

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