CONTROL SYSTEM FOR CONSTRUCTION MACHINERY, CONSTRUCTION MACHINERY AND CONTROL METHOD FOR CONSTRUCTION MACHINERY

Abstract

Control system (200) for a construction machine (100) comprising a working device (1), the control system (200) comprising: a target value generation unit (55) configured to generate a target value of an amount of control of the working device (1); a prediction unit (562) configured to calculate a prediction value of the amount of control of the working device (1) based on the target value and a prediction model for the working device (1), and to calculate a control amount for controlling the working device (1) based on the prediction value; and a command unit (58) configured to issue a control command for controlling the working device (1) based on the control amount, wherein the construction machine (100) contains a plurality of devices having the same or similar functions, wherein the prediction unit (562) calculates a prediction value of an operation amount of each of the devices in a functional area of ​​the respective device based on the target value and the prediction model, wherein the control system (200) includes a determination unit (61) configured to determine whether a first device of the devices reaches a limit value of its functional range, and wherein the prediction unit (562) calculates a drive amount to control the operation amount of a second device of the devices to prevent the first device of the devices from approaching the limit value of its operating range when it is determined that the first device of the devices should reach the limit value of its operating range.

Description

[0001] The present invention relates to a control system for a construction machine, a construction machine and a control method for a construction machine.

[0002] In a technical field related to construction machinery, a control system for a construction machine is known that moves the working device to follow a construction surface indicating a target shape of a construction target, as disclosed in WO 2014 / 167718 A1. Patent literature

[0003] WO 2014 / 167718 A1, US 2014 / 0 107 832 A1, US 2004 / 0 267 404 A1, US 6 968 264 B2.

[0004] US 2014 / 0 107 832 A1 discloses a control system for a construction machine including a work implement. The control system includes a target value generation unit configured to generate a target value of a control amount of the work implement; a prediction unit configured to calculate a prediction value of the control amount of the work implement based on the target value and a prediction model for the work implement, and to calculate a control amount for controlling the work implement based on the prediction value; and a command unit configured to output a control command for controlling the work implement based on the control amount. SummaryTechnical problem

[0005] The work equipment is controlled so that it does not dig below the construction surface. However, depending on the conditions on the construction site, the work equipment may dig below the construction surface. For example, if construction surfaces of various shapes are defined on the construction site, it may be difficult for the work equipment to follow the construction surface. Furthermore, if different work contents are required on the construction site, it may be difficult for the work equipment to follow the construction surface. There is a need for technology that can make the work equipment follow the construction surface regardless of the conditions on the construction site.

[0006] The object of the present invention is to ensure that the working device follows a construction surface regardless of a condition on a construction site. Solution to the problem

[0007] According to a first aspect of the present invention, a control system for a construction machine including a work implement comprises: a target value generation unit configured to generate a target value of an amount of control of the work implement; a prediction unit configured to calculate a prediction value of the amount of control of the work implement based on the target value and a prediction model for the work implement, and to calculate a drive amount for controlling the work implement based on the prediction value; and a command unit configured to output a control command for controlling the work implement based on the drive amount.Furthermore, the construction machine includes a plurality of devices having the same or similar functions, and wherein the prediction unit calculates, based on the target value and the prediction model, a prediction value of an actuation amount of each of the devices within a functional range of the respective device. The control system further includes a determination unit configured to determine whether a first device of the devices reaches a limit value of its functional range, and wherein the prediction unit calculates a drive amount to control the actuation amount of a second device of the devices to prevent the first device of the devices from approaching the limit value of its functional range when it is determined that the first device of the devices should reach the limit value of its functional range.

[0008] In a preferred embodiment, the working device contains a plurality of working elements that are movable relative to one another, the devices contain the working elements, and the respective functional area contains a movement area of ​​the respective one of the working elements.

[0009] In a further preferred embodiment, the construction machine includes a plurality of hydraulic actuators, the devices include the hydraulic actuators, and the respective functional area includes a hydraulic oil supply area defined for the respective one of the hydraulic actuators.

[0010] According to a second aspect of the present invention, a control system for a construction machine including a work implement comprises: a target value generation unit configured to generate a target value of an amount of control of the work implement; a prediction unit configured to calculate a prediction value of the amount of control of the work implement based on the target value and a prediction model for the work implement, and to calculate a control amount for controlling the work implement based on the prediction value; a command unit configured to output a control command for controlling the work implement based on the control amount.Furthermore, the work device includes a plurality of work elements movable relative to one another, the prediction unit calculates a prediction value of an angle of each of the work elements in a movement range of the respective work element based on the target value and the prediction model, the control system includes a determination unit configured to determine whether a first work element of the work elements is approaching an end of its movement range, and the prediction unit calculates a control amount to control an angle of a second work element of the work elements to prevent the first work element of the work elements from approaching the end of its movement range when it is determined that the first work element of the work elements is approaching the end of its movement range.

[0011] In a preferred embodiment, the work machine includes a boom, an arm, and a bucket, wherein the first working element of the working elements includes the bucket, the second working element of the working elements includes one or both of the boom and the arm, the construction machine includes a swing body configured to support the work machine, and the prediction unit calculates a drive amount to control, by an actuating device configured to actuate the work machine, an angle of one or both of the boom and the arm to prevent the bucket from approaching the end of its movement range when it is determined that the bucket is approaching the end of its movement range while the bucket is moved from a first position to a second position that is closer to the swing body than the first position.

[0012] In a further preferred embodiment, the construction machine includes a plurality of hydraulic actuators configured to actuate a plurality of the working elements, respectively, the prediction unit calculates, based on the target value and the prediction model, a prediction value of a hydraulic oil supply flow rate for each of the hydraulic actuators in a hydraulic oil supply range defined for the respective hydraulic actuator.The control system further includes a determination unit configured to determine whether a hydraulic oil supply flow rate for a first hydraulic actuator of the hydraulic actuators reaches a limit value of its hydraulic oil supply range, and the prediction unit calculates a drive amount to control a hydraulic oil supply flow rate for a second hydraulic actuator of the hydraulic actuators to prevent a hydraulic oil supply flow rate for the first hydraulic actuator of the hydraulic actuators from approaching the limit value of its hydraulic oil supply range when it is determined that the hydraulic oil supply flow rate for the first hydraulic actuator should reach the limit value of its hydraulic oil supply range.

[0013] In a further preferred embodiment, the control system further comprises an operation data acquisition unit configured to acquire operation data of an operating device configured to operate the working device, wherein the target value generation unit generates the target value based on the operation data.

[0014] In a further preferred embodiment, the control system comprises a construction surface detection unit configured to detect a construction surface indicating a target shape of a construction target, wherein the amount of control includes a position of a predetermined portion of the work implement, and the prediction unit calculates the control amount based on the prediction value and the construction surface so as to maintain a distance between the predetermined portion of the work implement and the construction surface.

[0015] In a further preferred embodiment, the amount of control includes a speed of movement of the implement.

[0016] In a further preferred embodiment, the prediction unit calculates the control amount such that the prediction value of the amount of control follows the target value.

[0017] In a further preferred embodiment, the prediction unit calculates the control amount such that a value of an evaluation function defined by the target value and the prediction value of the control amount is minimized.

[0018] In a further preferred embodiment according to the last-mentioned embodiment, the control system comprises a constraint condition calculation unit configured to calculate a first constraint condition related to the performance of the construction machine and a second constraint condition related to a position of the work implement, wherein the prediction unit calculates the control amount to satisfy the first constraint condition and the second constraint condition.

[0019] A third aspect of the present invention relates to a construction machine comprising a swing body configured to support a work implement and the control system for a construction machine according to any one of claims 1 to 12.

[0020] A fourth aspect of the present invention relates to a control method for a construction machine including a work implement and a plurality of devices having the same or similar functions, the method comprising: generating a target value of a control amount of the work implement; calculating a predicted value of a control amount of the work implement based on a target value of the control amount of the work implement and a predicted model for the work implement; calculating a control amount for controlling the work implement based on the predicted value; outputting a control command for controlling the work implement based on the control amount; calculating a predicted value of an operation amount of each of the devices in a functional range of the respective device based on the target value and the predicted model;Determining whether a first device of the devices reaches a limit value of its operating range, and calculating a drive amount to control the actuation amount of a second device of the devices to prevent the first device of the devices from approaching the limit value of its operating range when it is determined that the first device of the devices should reach the limit value of its operating range; Advantageous effects of the invention

[0021] According to the present invention, the working device can be caused to follow the construction surface regardless of the condition on the construction site. Brief description of the drawings Fig. 1 is a perspective view showing an example of a construction machine according to the present embodiment. Fig. 2 is a block diagram illustrating a control system for the construction machine according to the present embodiment. Fig. 3 is a diagram schematically illustrating the construction machine according to the present embodiment. Fig. 4 is a diagram schematically illustrating a blade according to the present embodiment. Fig. 5 is a functional block diagram showing a control device according to the present embodiment. Fig. 6 is a diagram illustrating a method of calculating a target translation speed of the blade by a target translation speed calculating unit according to the present embodiment. Fig. 7 is a graph showing an example of a speed limit table according to the present embodiment. Fig. 8 is a diagram illustrating a method of calculating a target rotational speed of the blade by a target rotational speed calculating unit according to the present embodiment. Fig. 9 is a diagram illustrating an example of operation of the construction machine according to the present embodiment. Fig. 10 is a flowchart illustrating a control method for the construction machine according to the present embodiment. Fig. 11 is a graph showing a result of comparison between the control of the work machine by the control method according to the present embodiment and the control of the work machine by a control method according to a comparative example. Fig. 12 is a block diagram illustrating an example of a computer system according to the present embodiment. Description of the embodiments

[0022] Embodiments according to the present invention will be described below with reference to the drawings

[0023] In the following description, a three-dimensional vehicle body coordinate system (X, Y, Z) is defined and a positional relationship between respective component elements is described. The vehicle body coordinate system represents a coordinate system whose origin is set on a construction machine. The vehicle body coordinate system is defined by an X-axis extending in a defined direction with respect to the origin set on the construction machine, a Y-axis orthogonal to the X-axis, and a Z-axis orthogonal to both the X-axis and the Y-axis. A direction parallel to the X-axis is an X-axis direction. A direction parallel to the Y-axis is a Y-axis direction. A direction parallel to the Z-axis is a Z-axis direction. A rotation or tilt direction about the X-axis is a θX direction. A rotation or tilt direction about the Y-axis is a θY direction. A rotation or tilt direction about the Z-axis is a θZ direction. [Construction machine]

[0024] Fig. 1 is a perspective view showing an example of a construction machine 100 according to the present embodiment. In the present embodiment, an example of the construction machine 100 is described as an excavator. In the following description, the construction machine 100 is conveniently referred to as an excavator 100.

[0025] As in Fig. As shown in Figure 1, the excavator 100 includes a working device 1 driven by hydraulic pressure, a swing body 2 configured to support the working device 1, and a traveling body 3 configured to support the swing body 2. The swing body 2 has a cab 4 into which an operator enters. A seat 4S is arranged in the cab 4, on which the operator sits. The swing body 2 is pivotable about a pivot axis RX, with the swing body 2 being supported by the traveling body 3.

[0026] The traveling body 3 has a pair of crawler tracks 3C. The excavator 100 travels by rotating the crawler tracks 3C. Note that the traveling body 3 may be equipped with tires.

[0027] The working device 1 is supported by the swing body 2. The working device 1 comprises a plurality of working elements that are movable relative to one another. The plurality of working elements have the same or similar functions. In other words, each of the plurality of working elements moves relative to the swing body 2 to perform the work required by the excavator 100, such as excavation, leveling, and loading.

[0028] The working elements include a boom 6, an arm 7, and a bucket 8. The boom 6 is connected to the swing body 2. The arm 7 is connected to a distal end of the boom 6. The bucket 8 is connected to a distal end of the arm 7. The bucket 8 has a cutting edge 9. In the present embodiment, the cutting edge 9 of the bucket 8 is the edge of a straight cutting edge. The cutting edge 9 of the bucket 8 may be the tip of a protruding tooth provided on the bucket 8.

[0029] The boom 6 is rotatable about a boom axis AX1 relative to the swivel body 2. The arm 7 is rotatable about an arm axis AX2 relative to the boom 6. The bucket 8 is rotatable about a bucket axis AX3, a tilt axis AX4, and a rotation axis AX5 relative to the arm 7. The boom axis AX1, the arm axis AX2, and the bucket axis AX3 are parallel to the Y-axis. The tilt axis AX4 is orthogonal to the bucket axis AX3. The rotation axis AX5 is orthogonal to the bucket axis AX3 and the tilt axis AX4. The swivel axis RX is parallel to the Z-axis. The X-axis direction is a front-rear direction of the swing body 2. The Y-axis direction is a vehicle width direction of the swing body 2. The Z-axis direction is a vertical direction of the swing body 2. A direction of the work machine 1 relative to the operator sitting on the seat 4S is a front direction.

[0030] Fig. 2 is a block diagram illustrating a control system 200 for the excavator 100 according to the present embodiment. Fig. 3 is a diagram schematically illustrating the excavator 100 according to the present embodiment. Fig. 4 is a schematic diagram of the blade 8 according to the present embodiment.

[0031] As in Fig. 2, the control system 200 for the excavator 100 includes an engine 5, a plurality of hydraulic cylinders 10 configured to operate the work implement 1, a swing motor 16 configured to drive the swing body 2, a hydraulic pump 17 configured to discharge hydraulic oil, a valve device 18 configured to distribute the hydraulic oil discharged from the hydraulic pump 17 to each of the plurality of hydraulic cylinders 10 and the swing motor 16, a position calculation device 20 configured to calculate position data of the swing body 2, an angle detection device 30 configured to detect angles θ of the work implement 1, an actuating device 40 configured to actuate the work implement 1 and the swing body 2, and a control device 50.

[0032] The work tool 1 is operated by the power generated by the hydraulic cylinders 10. Each of the hydraulic cylinders 10 is driven based on the hydraulic oil supplied by the hydraulic pump 17. The hydraulic cylinder 10 is a hydraulic actuator configured to actuate the working elements of the work tool 1. The plurality of hydraulic cylinders 10 have the same or similar functions. In other words, the plurality of hydraulic cylinders 10 have functions for actuating the plurality of working elements.

[0033] The hydraulic cylinder 10 includes a boom cylinder 11 configured to operate the boom 6, an arm cylinder 12 configured to operate the arm 7, and a bucket cylinder 13, a tilt cylinder 14, and a rotation cylinder 15 configured to operate the bucket 8. The boom cylinder 11 generates power to rotate the boom 6 about the boom axis AX1. The arm cylinder 12 generates power to rotate the arm 7 about the arm axis AX2. The bucket cylinder 13 generates power to rotate the bucket 8 about the bucket axis AX3. The tilt cylinder 14 generates power to rotate the bucket 8 about the tilt axis AX4. The rotation cylinder 15 generates power to rotate the bucket 8 about the rotation axis AX5.

[0034] In the following description, the rotation of the blade 8 about the blade axis AX3 is expediently referred to as blade rotation and the rotation of the blade 8 about the tilting axis AX4 is expediently referred to as tilting rotation and the rotation of the blade 8 about the rotation axis AX5 is expediently referred to as rotation.

[0035] The slewing body 2 slews using the power generated by the slewing motor 16. The slewing motor 16 is a hydraulic motor and is driven by the hydraulic oil supplied by the hydraulic pump 17. The slewing motor 16 generates power to cause the slewing body 2 to slew about the slewing axis RX.

[0036] The motor 5 is mounted on the swivel body 2. The motor 5 generates power to drive the hydraulic pump 17.

[0037] The hydraulic pump 17 supplies the hydraulic oil to drive the hydraulic cylinder 10 and the swivel motor 16.

[0038] The valve device 18 includes a plurality of valves configured to distribute the hydraulic oil supplied from the hydraulic pump 17 to the plurality of hydraulic cylinders 10 and the swing motor 16. The valve device 18 adjusts the flow rate of the hydraulic oil supplied to each of the plurality of hydraulic cylinders 10. By adjusting the flow rate of the hydraulic oil supplied to the hydraulic cylinder 10, the operating speed of the hydraulic cylinder 10 is adjusted. The valve device 18 regulates the flow rate of the hydraulic oil supplied to the swing motor 16. By adjusting the flow rate of the hydraulic oil supplied to the swing motor 16, the rotational speed of the swing motor 16 is adjusted.

[0039] The position calculation device 20 calculates the position data of the swivel body 2. The position data of the swivel body 2 contain the position of the swivel body 2, the attitude of the swivel body 2 and the orientation of the swivel body 2. The position calculation device 20 has a position calculator 21 configured to calculate the position of the swivel body 2, a position calculator 22 configured to calculate the attitude of the swivel body 2, and an orientation calculator 23 configured to calculate the orientation of the swivel body 2.

[0040] The position computer 21 calculates the position of the swivel body 2 in a global coordinate system, as the position of the swivel body 2. The position computer 21 is arranged in the swivel body 2. The global coordinate system represents a coordinate system whose origin is on the Earth. The global coordinate system is a coordinate system defined by a global navigation satellite system (GNSS). The GNSS is a global navigation satellite system. A global positioning system (GPS) is an example of a global navigation satellite system. The GNSS has a plurality of positioning satellites. The GNSS acquires a position defined by coordinate data of a latitude, a longitude, and an altitude. The swivel body 2 is equipped with a GPS antenna.The GPS antenna receives a radio wave from a GPS satellite and outputs a signal generated based on the received radio wave to the position calculator 21. The position calculator 21 calculates the position of the rotating body 2 in the global coordinate system based on the signal supplied from the GPS antenna. The position calculator 21 calculates the position of a representative point O of the rotating body 2, such as shown in FIG. Fig. 3. In the Fig. In the example shown in Figure 3, the representative point O of the swivel body 2 is set on the swivel axis RX. The representative point O can be set on the boom axis AX1.

[0041] The attitude computer 22 calculates the inclination angle of the swivel body 2 relative to a horizontal plane in the global coordinate system, as the attitude of the swivel body 2. The attitude computer 22 is arranged in the swivel body 2. The attitude computer 22 contains an inertial measurement unit (IMU). The inclination angle of the swivel body 2 relative to the horizontal plane includes a roll angle α, which indicates an inclination angle of the swivel body 2 in the vehicle width direction, and a pitch angle β, which indicates an inclination angle of the swivel body 2 in the front-rear direction.

[0042] The orientation computer 23 calculates the orientation of the swivel body 2 relative to a reference orientation in the global coordinate system as the orientation of the swivel body 2. The reference orientation is, for example, north. The orientation computer 23 is arranged in the swivel body 2. The orientation computer 23 contains a gyroscope sensor. The orientation computer 23 can calculate the orientation based on the signal supplied by the GPS antenna. The orientation of the swivel body 2 relative to the reference orientation includes a yaw angle γ, which indicates an angle formed by the reference orientation and the orientation of the swivel body 2.

[0043] The angle detection device 30 detects the angle θ of the working device 1. The angle detection device 30 is arranged in the working device 1. As in Fig. 3 and Fig. 4, the angles θ of the work tool 1 include a boom angle θ1 indicating the angle of the boom 6 relative to the Z axis, an arm angle θ2 indicating the angle of the arm 7 relative to the boom 6, a bucket angle θ3 indicating the angle of the bucket 8 in a bucket rotation direction relative to the arm 7, a tilt angle θ4 indicating the angle of the bucket 8 in a tilt rotation direction relative to an XY plane, and a rotation angle θ5 indicating the angle of the bucket 8 in a rotation direction relative to a YZ plane.

[0044] The angle detection device 30 includes a boom angle detector 31 that detects the boom angle θ1, an arm angle detector 32 that detects the arm angle θ2, a bucket angle detector 33 that detects the bucket angle θ3, a tilt angle detector 34 that detects the tilt angle θ4, and a rotation angle detector 35 that detects the rotation angle θ5. The angle detection device 30 may include a stroke sensor configured to detect a stroke of the hydraulic cylinder 10, or it may include an angle sensor, such as a stroke sensor, configured to detect the angles θ of the work machine 1. When the angle detection device 30 includes the stroke sensor, the angle detection device 30 calculates the angles θ of the work machine 1 based on the detection data of the stroke sensor.

[0045] The operating device 40 is operated by the operator to drive the hydraulic cylinder 10 and the swing motor 16. The operating device 40 is arranged in the cab 4. The operator's operation of the operating device 40 controls the work implement 1. The operating device 40 includes a lever that is operated by the operator of the excavator 100. The lever of the operating device 40 includes a right operating lever 41, a left operating lever 42, and a tilt operating lever 43.

[0046] When the right control lever 41 is moved forward in a neutral position, the boom 6 is lowered, and when the right control lever 41 is moved backward, the boom 6 is raised. When the right control lever 41 is moved right in the neutral position, the bucket 8 tilts, and when the right control lever 41 is moved left, the bucket 8 digs.

[0047] When the left operating lever 42 is operated forward in a neutral position, the arm 7 tilts, and when the left operating lever 42 is operated backward, the arm 7 digs. When the left operating lever 42 is operated to the right in the neutral position, the swing body 2 swings to the right, and when the left operating lever 42 is operated to the left, the swing body 2 swings to the left.

[0048] The operation of the tilt control lever 43 causes a tilting rotation or rotation of the bucket 8. [Control device]

[0049] Fig. 5 is a functional block diagram illustrating the control device 50 according to the present embodiment. The control device 50 includes a position data acquisition unit 51, an angle data acquisition unit 52, an operation data acquisition unit 53, a design surface acquisition unit 54, a target value generation unit 55, a model prediction control unit 56, a constraint calculation unit 57, a command unit 58, a determination unit 61, and a storage unit 60.

[0050] The position data acquisition unit 51 acquires the position data of the swivel body 2 from the position calculation device 20. The position data of the swivel body 2 includes the position of the swivel body 2, the attitude of the swivel body 2, and the orientation of the swivel body 2.

[0051] The angle data acquisition unit 52 acquires angle data indicating the angles θ of the work machine 1 from the angle detection device 30. The angle data of the work machine 1 includes the boom angle θ1, the arm angle θ2, the bucket angle θ3, the tilt angle θ4, and the rotation angle θ5.

[0052] The operation data acquisition unit 53 acquires operation data of the operating device 40 that operates the work implement 1. The operation data of the operating device 40 includes an operation amount of the operating device 40. The operating device 40 is equipped with an operation amount sensor that detects an operation amount of each lever. The operation data acquisition unit 53 acquires the operation data of the operating device 40 from the operation amount sensor of the operating device 40.

[0053] The construction surface acquisition unit 54 acquires a construction surface indicating a target shape of a construction target. The construction surface indicates a three-dimensional target shape after construction by the excavator 100. In the present embodiment, a construction surface data supply device 70 generates construction surface data indicating the construction surface. The construction surface acquisition unit 54 acquires the construction surface data from the construction surface data supply device 70. The construction surface data supply device 70 may be provided at a location remote from the excavator 100. The construction surface data generated by the construction surface data supply device 70 may be transmitted to the control device 50 via a communication system. Note that the construction surface data generated by the construction surface data supply device 70 may be stored in the storage unit 60.The construction surface acquisition unit 54 can acquire the construction surface data from the storage unit 60.

[0054] The target value generation unit 55 generates a target value for an amount of control of the work machine 1. In the present embodiment, the amount of control of the work machine 1 includes one or both of the moving speed of the bucket 8 and the position of a predetermined portion of the bucket 8. The predetermined portion of the bucket 8 includes the cutting edge 9 of the bucket 8. The moving speed of the bucket 8 includes a moving speed of the cutting edge 9. The position of the predetermined portion of the bucket 8 includes the position of the cutting edge 9. The target value generation unit 55 generates the target value of the amount of control of the work machine 1 based on the operation data acquired by the operation data acquisition unit 53.

[0055] In the following description, it is assumed that the predetermined portion of the blade 8 is the cutting edge 9. Note that the predetermined portion of the blade 8 does not necessarily have to be the cutting edge 9. The predetermined portion of the blade 8 may be a bottom surface (bottom surface) of the blade 8.

[0056] The moving speed of the blade 8 includes a translational speed and a rotational speed of the blade 8. The translational speed of the blade 8 represents a moving speed in the X-axis direction, the Y-axis direction, and the Z-axis direction. The rotational speed of the blade 8 represents a rotational angular speed in the θX direction, the θY direction, and the θZ direction. In the present embodiment, the target value generation unit 55 includes a target translational speed calculation unit 551 configured to calculate a target translational speed v targetwhich is a target value of the translational speed, and a target rotational speed calculation unit 552 which is configured to calculate a target rotational speed ω target which is a target value of the rotational speed. The target value generation unit 55 calculates both the target translation speed v target as well as the target rotational speed ω target based on the angle data acquired by the angle data acquisition unit 52, the operation data acquired by the operation data acquisition unit 53, and the construction area acquired by the construction area acquisition unit 54.

[0057] Fig. 6 is a diagram showing a method for calculating the target translation speed v targetof the bucket 8 by the target translation speed calculation unit 551 according to the present embodiment. The target translation speed calculation unit 551 includes a translation speed calculation unit 551A configured to calculate the translation speed of the bucket 8 based on the operation data of the operating device 40 and the angle data of the work implement 1, a speed limit calculation unit 551B configured to calculate a speed limit of the bucket 8 based on a distance between the cutting edge 9 and the design surface and the design surface data, a PI control unit 551C, and a deceleration processing unit 551D.

[0058] The target translation speed calculation unit 551 calculates the target translation speed v targetof the bucket 8 to avoid digging below the construction surface. The target translation speed v target the blade 8 is calculated based on formulas (1) to (6). vtarget=wR1[100000001](a+b)+jv[θ˙ope1 0 0 0 0]T a={(1vsagyo⋅1eXZ)1eXZ((1vsagyo⋅1eXZ)>VMAX)VMAX1eXZ((1vsagyo⋅1eXZ)≤VMAX) b= 1vsagyo−(1vsagyo⋅1eXZ)1eXZ 1eXZ=−[100000001 ] 1Rwn vsagyo=Jv[0000001000001000000000000]θ˙ope J=[JvJω]

[0059] n ∈ R 3 is a unit normal vector of the construction surface closest to the cutting edge 9, w R1 ∈ R 3×3 is a rotation matrix for transformation from the vehicle body coordinate system to the global coordinate system, v sagyo ∈ R 3is a translational speed component of the bucket operated by the boom 6 and the arm 7 on a work implement plane (XZ plane in the vehicle body coordinate system) of the translational speed when the work implement 1 is operated based on the operation of the operating device 40, and V MAX is a maximum speed of the bucket 8 in a direction perpendicular to the construction surface to prevent digging below the construction surface. J v ∈ R 3×5 and J ω ∈ R 3×5 represent a translational velocity component and a rotational velocity component of the Jacobian matrix, respectively.

[0060] The target translation speed calculation unit 551 is configured to calculate the distance between the cutting edge 9 and the design surface based on the position data of the swing body 2 acquired by the position data acquisition unit 51, the angle data of the work tool 1 acquired by the angle data acquisition unit 52, and the work tool data stored in the storage unit 60. As shown in Fig. 3 and Fig. 4, the work tool data includes a boom length L1, an arm length L2, a bucket length L3, a tilt length L4, and a bucket width L5. The boom length L1 is a distance between the boom axis AX1 and the arm axis AX2. The arm length L2 is a distance between the arm axis AX2 and the bucket axis AX3. The bucket length L3 is a distance between the bucket axis AX3 and the cutting edge 9 of the bucket 8. The tilt length L4 is a distance between the bucket axis AX3 and the tilt axis AX4. The bucket width L5 is a dimension in the width direction of the bucket 8. The work tool data includes bucket profile data indicating the shape and dimensions of the bucket 8. The bucket profile data includes outer surface data of the bucket 8, which includes the profile of an outer surface of the bucket 8. The bucket profile data includes coordinate data of a plurality of outline points RP of the bucket 8 based on the predetermined portion of the bucket 8.

[0061] The target translation speed calculation unit 551 calculates position data of each of the contour points RP. The target translation speed calculation unit 551 calculates a relative position between the representative point O of the swing body 2 and each of the plurality of contour points RP in the vehicle body coordinate system. The target translation speed calculation unit 551 is configured to calculate the relative position between the representative point O of the swing body 2 and each of a plurality of outline points RP of the bucket 8 in the vehicle body coordinate system based on the work machine data including the boom length L1, the boom length L1, the arm length L2, the bucket length L3, the tilt length L4, the bucket width L5, and the bucket profile data, as well as the angle data of the work machine 1 including the boom angle θ1, the boom angle θ2, the bucket angle θ3, the tilt angle θ4, and the rotation angle θ5.Setting the outline points RP on the cutting edge 9 allows the target translation speed calculation unit 551 to calculate a relative position between the representative point O and the cutting edge 9. The design surface is defined in the vehicle body coordinate system. Therefore, the target translation speed calculation unit 551 can calculate the distance between the cutting edge 9 and the design surface in the vehicle body coordinate system. Furthermore, the target translation speed calculation unit 551 calculates a position of each of the plurality of outline points RP in the global coordinate system.The target translation speed calculation unit 551 can calculate the position of each outline point RP of the bucket 8 in the global coordinate system based on an absolute position of the representative point O of the swing body 2 and the relative position between the representative point O of the swing body 2 and the position of the outline point RP of the bucket 8.

[0062] The speed limit calculation unit 551B determines a speed limit of the boom 6 in the direction perpendicular to the construction surface using a speed limit table indicating a relationship between the distance between the bucket 8 and the construction surface and a speed limit of the work machine 1.

[0063] Fig. Fig. 7 is a graph showing an example of the speed limit table according to the present embodiment. As shown in Fig. As shown in Figure 7, the speed limit table shows the relationship between the distance between the cutting edge 9 and the design surface and the speed limit of the work tool 1. When the distance between the cutting edge 9 and the design surface is 0, the speed of the work tool 1 in the direction perpendicular to the design surface becomes 0 in the speed limit table. When the cutting edge 9 is located above a design surface, the distance between the cutting edge 9 and the design surface has a positive value in the speed limit table. When the cutting edge 9 is located below the design surface, the distance between the cutting edge 9 and the design surface has a negative value. In the speed limit table, a speed for moving the cutting edge 9 upward has a positive value.When the distance between the cutting edge 9 and the design surface is equal to or less than a work implement control threshold th, which has a positive value, the speed limit of the work implement 1 is defined based on the distance between the cutting edge 9 and the design surface. When the distance between the cutting edge 9 and the design surface is equal to or greater than the work implement control threshold th, an absolute value of the speed limit of the work implement 1 has a value greater than a maximum value of a target speed of the work implement 1.In other words, when the distance between the cutting edge 9 and the design surface is equal to or greater than the work tool control threshold th, an absolute value of the target speed of the work tool 1 is always smaller than the absolute value of the speed threshold, and thus the boom 6 is always controlled at the target speed.

[0064] Fig. 8 is a diagram illustrating a method for calculating the target rotational speed ω target of the blade 8 by the target rotational speed calculation unit 552 according to the present embodiment. The target rotational speed calculation unit 552 includes an actual position calculation unit 552A configured to calculate an actual position R cur of the bucket 8 based on the angle data of the working device 1, a target position calculation unit 552B which is configured to calculate a target position R targetof the blade 8 on the basis of the actuation data of the actuating device 40 and the design surface data, a rotational speed calculation unit 552C which is configured to calculate a rotational speed ω' target based on the current situation R cur and the target position R target of the blade 8, and a P-control unit 552D which is arranged to carry out a P-control of the rotational speed ω' target to achieve the target rotational speed ω target to calculate.

[0065] The target rotational speed ω target is calculated based on formulas (7) to (10). ωtarget'=Rcurω θ=cos−1(r11+r22+r33−12) ω={[0 0 0]T(θ=0)θ2ΔTtargetsin θ [r32−r23r13−r31r21−r12](θ≠0) R=[r11r12r13r21r22r23r31r32r33]=RcurTRtarget

[0066] ΔT targetis a parameter corresponding to a time required to correct the position of the blade 8. The P control unit 552D calculates the target rotational speed ω target by performing the P control based on the rotation speed ω' calculated by the rotation speed calculation unit 552C target carries out.

[0067] The model prediction control unit 56 calculates a prediction value of the amount of control of the work device 1 based on the target value of the amount of control of the work device 1 generated by the target value generation unit 55 and a prediction model for the work device 1. The model prediction control unit 56 calculates a drive amount for controlling the work device 1 based on the prediction value.The model prediction control unit 56 includes a prediction model storage unit 561 configured to store the prediction model for the work device 1, and a prediction unit 562 configured to calculate the prediction value of the amount of control of the work device 1 based on the target value of the amount of control of the work device 1 and the prediction model for the work device 1, and to calculate the drive amount for controlling the work device 1 based on the prediction value of the amount of control of the work device 1.

[0068] In the prediction model storage unit 561, a prediction model for the excavator 100 including the work tool 1 is stored. The prediction model includes a dynamic model for the excavator 100. The prediction model includes a model for the swing body 2 that swings around the swing axis RX, a model for the boom 6 that rotates around the boom axis AX1, a model for the arm 7 that rotates around the arm axis AX2, and a model for the bucket 8 that rotates around the bucket axis AX3, the tilt axis AX4, and the rotation axis AX5.

[0069] The prediction model is represented by a discrete state equation and an output equation. The state equation of the prediction model for controlling the excavator 100, discretized with a sampling time ΔT, is represented by formula (11). The matrices of the state equation are represented by formulas (12) and (13). The output equation of the prediction model is represented by formula (14). [θ(t+1)θ˙(t+1)]=A[θ(t)θ˙(t)]+B[ τ(t)−Co(t)Ctay(t)] A=[I5×5I5×5ΔTO5×5I5×5]∈R10×10 B=[12ΔT2M−112ΔT2M−1O5×4 ΔTM−1 ΔTM−1O5×4]∈R10×14 [v(t)ω(t)θ(t)Tθ˙(t)Td(t)QA(t)]=C[θ(t)θ˙(t)]+D[τ(t)−Co(t)Ctay(t)]

[0070] Each of M ∈ R5×5 and Co ∈ R 5 is an inertial matrix of an equation of motion and a Coriolis force / gravity vector. C ray ∈ R 2np is a constant term when a Tailor expansion of np by an angle θ is performed at the predetermined time t. n p is the number of design surfaces to be considered. The outputs of the output equation of the prediction model are an angle θ, an angular velocity, the target translation velocity v target , the target rotational speed ω target , the distance d between the cutting edge 9 and the design surface and the flow rate Q of the hydraulic oil.

[0071] The prediction unit 562 performs an optimization operation based on the prediction model and calculates the prediction value of the amount of control of the work machine 1. As described above, in the present embodiment, the amount of control of the work machine 1 includes one or both of the moving speed of the bucket 8 and the position of the predetermined portion of the bucket 8. The predetermined portion of the bucket 8 includes the cutting edge 9. Further, the amount of control of the work machine 1 includes an angular velocity of the boom 6, an angular velocity of the arm 7, and an angular velocity of the bucket 8. The angular velocity of the bucket 8 includes an angular velocity about the bucket axis AX3, an angular velocity about the tilt axis AX4, and an angular velocity about the rotation axis AX5.

[0072] The prediction unit 562 predicts a value on the left side of formula (14) several steps before the current time.

[0073] The prediction unit 562 calculates the control amount for controlling the work machine 1 based on at least one of a prediction value of the movement speed of the bucket 8, a prediction value of the angular velocity of each axis, a prediction value of the position of the cutting edge 9 of the bucket 8, and a prediction value of the flow rate of the hydraulic oil. The prediction unit 562 calculates the control amount such that the prediction value of the control amount follows its target value.

[0074] In the present embodiment, the prediction unit 562 calculates the drive amount so that the bucket 8 follows a target design surface at a predetermined posture, based on the prediction value of the moving speed of the bucket 8, the prediction value of the angular velocity of each axis, the prediction value of the position of the cutting edge 9 of the bucket 8, the prediction value of the flow rate of the hydraulic oil, a prediction value of a swing speed of the swing body 2, and the design surface. In other words, the prediction unit 562 calculates the drive amount so that the bucket 8 does not dig below the design surface and the position of the cutting edge 9 and the position of the design surface coincide with each other.

[0075] The prediction unit 562 calculates the control amount for controlling the work device 1 and the swing body 2 such that an evaluation function has a minimum value and each constraint condition is satisfied.

[0076] In model prediction control, the evaluation function shown in formula (15) is generally used. E(t)=Ey(t)+Eu(t)+EΔu(t)+Ec(t)

[0077] E y (t) is a difference between a target value and a prediction value in the output, E u (t) is a difference between a target value and a prediction value in the input, EΔ u (t) is an order of magnitude of the change in the input, and E c (t) is a penalty function that is imposed when the constraints described later are not met. In the present embodiment, E u (t) = 0 and EΔ u(t) = 0, and the tracking error in the output relative to the target value in the output is used as the evaluation function. The evaluation function is shown in formulas (16) and (17). E(t)=∑i=1HpΔri(t+i|t)TWΔri(t+i|t)+Ec(t) Δri(t+i|t)=ri(t+i|t)−y(t+i|t)

[0078] r(t + ilt) is a target value of time t+1 at time t, y(t + ilt) is a plant output predicted at time t+i, H p is a prediction horizon that determines how many steps ahead a prediction is made, and W is a diagonal matrix that weights prediction variables.

[0079] The constraint calculation unit 57 calculates the constraints. The constraints include a first constraint related to the power of the excavator 100 and a second constraint related to the position of the bucket 8. The prediction unit 562 calculates the control amount so that the constraints calculated by the constraint calculation unit 57 are satisfied.

[0080] The excavator 100 as the control target has a limitation on the angle θ, angular velocity, angular acceleration, and hydraulic oil flow rate of the work tool 1. In other words, the working elements of the work tool 1 each have an operating range that indicates a range within which the working element functions. The operating range of the working elements each includes a movement range of each working element. For example, each angle θ by which the work tool 1 is movable has a limit value. Likewise, each of the angular velocity and angular acceleration of the work tool 1 has a limit value.

[0081] In addition, the flow rate of the hydraulic oil discharged from the hydraulic pump 17 has a limit value. In other words, the flow rate of the hydraulic oil delivered from the hydraulic pump 17 to the hydraulic cylinder 10 has a limit value depending on the performance or the like of the hydraulic pump 17. In addition, each hydraulic cylinder 10 has an operating range that indicates a range in which the hydraulic cylinder 10 functions. The operating range of the hydraulic cylinder 10 includes a hydraulic oil supply range defined for the hydraulic cylinder 10. For the hydraulic cylinder 10, a minimum value Q wm_m i n and a maximum value Q wm_max , the limits of a hydraulic oil supply flow rate Q wm , which indicates the flow rate of hydraulic oil supplied from the hydraulic pump 17 via the valve device 18 to the hydraulic cylinder 10. The hydraulic oil supply flow rate Q wmfor the hydraulic cylinder 10 contains a hydraulic oil supply flow rate Q bm for the boom cylinder 11, a hydraulic oil supply flow rate Q ar for the arm cylinder 12 and a hydraulic oil supply flow rate Q bk for the bucket cylinder 13. The same applies to the tilt cylinder and the rotation cylinder. For the boom cylinder 11, a minimum value Q bm_min and a maximum value Q bm_max defines the limits of the hydraulic oil supply flow rate Q bm For the boom cylinder 12, a minimum value Q ar_min and a maximum value Q ar_max defines the limits for the hydraulic oil supply flow rate Q ar For the bucket cylinder 13, a minimum value Q bk_min and a maximum value Q bk_max defines the limits for the hydraulic oil supply flow rate Q bkThe same applies to the tilt cylinder 14 and the rotation cylinder 15. The hydraulic oil supply range defined for the hydraulic cylinder 10 lies in the range between the minimum value Q wm_min and the maximum value Q wm_max .

[0082] As described above, the excavator 100 has a hardware limitation. Therefore, it is necessary to consider the first constraint indicating a hardware limitation of the excavator 100 in the model prediction control. The constraint calculation unit 57 calculates the first constraint including the angle θ, the angular velocity, the angular acceleration, and the flow rate of the hydraulic oil of the work equipment 1. The prediction unit 562 calculates the drive amount to satisfy the first constraint.

[0083] The boundary conditions for the angles θ, the angular velocity and the flow rate of the hydraulic oil are shown in formulas (18) to (21). θmin≤θ(t)≤θmax θ˙min≤θ(t)≤θ˙max QA(t)=∑i=15Qi≤QAmax QA=Gθ˙≤QAmax132×1

[0084] The boundary conditions of the angular acceleration are shown in formula (22). θ¨min≤θ¨(t)≤θ¨max

[0085] In the present embodiment, the constraint calculation unit 57 converts the angular acceleration constraint into the torque constraint. The angular acceleration constraint after the conversion is shown in Formula (23). θ¨min≤M−1(t)τ(t)−M−1(t)Co(t)≤θ¨max

[0086] When controlling the work machine 1, the bucket 8 must be prevented from digging below the design surface. In other words, the bucket 8 has a position limit to prevent it from digging below the design surface. Therefore, the second constraint specifying the position limit of the bucket 8 must also be considered in the model prediction control. The constraint calculation unit 57 calculates the second constraint including the position of the bucket 8 relative to the design surface. The prediction unit 562 calculates the control amount to satisfy the second constraint.

[0087] An output d(t) indicates the distance between the cutting edge 9 and the construction surface. An equation of the i-th construction surface is given by a unit normal vector n i as np + d i= 0. Formulas (24) and (25) show the boundary conditions to prevent the right and left ends of the cutting edge 9 from digging below the design surface. ni⋅pL(t)≥−di ni⋅pR(t)≥−di

[0088] The coordinates of the cutting edge 9 are nonlinear with respect to an angle θ in a state variable. Therefore, a linear approximation is applied, as shown in formulas (26) and (27). ni⋅pL(t)=CiLθ(t)+CtayiL ni⋅pR(t)=CiRθ(t)+CtayiR

[0089] The prediction unit 562 uses the evaluation functions shown in formulas (16) and (17) to perform the optimization operation in the model prediction controller to satisfy the constraints shown in formulas (18) to (27). An optimization problem in the present embodiment is shown in formula (28). For the optimization, for example, quadratic programming (QP) is used, but other calculation methods may also be used. depending on minimize E(t)τ(1),...,τ(1−(H-1)ΔT)θmin≤θ(t)≤θmaxθ˙min≤θ˙(t)≤θ˙maxθ¨min≤M−1τ−M−1Co≤θ¨max Gθ˙≤QAmax13×1ni⋅pL(t)=CiLθ(t)+CtayL≥−dini⋅pR(t)=CiRθ(t)+CtayR≥−di(i=1,2,...,np)

[0090] τ(t) is a control input torque for a control system and is a solution of the optimization operation. H u is a control horizon that determines how many steps in advance the inputs in the optimization problem should be treated.

[0091] The command unit 58 outputs a control command for controlling the working device 1 based on the control amount calculated by the prediction unit 562.

[0092] In the present embodiment, the prediction unit 562 calculates a prediction value of an operation amount in the operating range of each working element or hydraulic cylinder 10 based on the target value and the prediction model of the working device 1.

[0093] In other words, the prediction unit 562 calculates a prediction value of the angle θ of each working element within the range of movement of the working element. The prediction unit 562 calculates a prediction value of the boom angle θ1 within the range of movement of the boom 6. The prediction unit 562 calculates a prediction value of the arm angle θ2 within the range of movement of the arm 7. The prediction unit 562 calculates a prediction value for the bucket angle θ3 within the range of movement of the bucket 8. The same applies to the tilt angle θ4 and the rotation angle θ5.

[0094] Further, the prediction unit 562 predicts the hydraulic oil supply flow rate Q wm in the hydraulic oil supply range of each hydraulic cylinder 10. As described above, the hydraulic oil supply range defined for the hydraulic cylinder 10 is in the range between the minimum value Q wm_min and the maximum value Q wm_max. The prediction unit 562 predicts the hydraulic oil supply flow rate Q bm in the hydraulic oil supply area of ​​the boom cylinder 11. The prediction unit 562 predicts the hydraulic oil supply flow rate Q ar in the hydraulic oil supply area of ​​the boom cylinder 12. The prediction unit 562 predicts the hydraulic oil supply flow rate Q bk in the hydraulic oil supply area of ​​the bucket cylinder 13. The same applies to the tilt cylinder 14 and the rotation cylinder 15.

[0095] The determination unit 61 determines whether a first working element of the plurality of working elements reaches a limit value of the operating range. As described above, the operating range of each working element includes the moving range of the working element. The limit value of the operating range of the working element includes an end of the moving range of the working element (an end of a stroke). In other words, the determination unit 61 determines whether the first working element is approaching the end of the moving range. The determination unit 61 is configured to determine whether the working element is approaching the moving range based on detection data from the angle detection device 30.The approach of the working element to the end of the stroke, which is the end of the range of motion, represents that a difference between an actual angle of the working element (angle detected by the angle detecting device 30) and a stroke end angle indicating the end of the stroke of the working element is equal to or less than a predetermined threshold.

[0096] Furthermore, the determination unit 61 determines whether a first hydraulic cylinder 10 of the plurality of hydraulic cylinders 10 reaches the limit value of the operating range. As described above, the operating range of the hydraulic cylinder 10 includes the hydraulic oil supply range defined for the hydraulic cylinder 10. The limit value of the operating range of the hydraulic cylinder 10 includes the minimum value Q wm_min and the maximum value Q wm _ maxof the hydraulic oil supply area. In other words, the determination unit 61 determines whether the hydraulic oil supply flow rate Q m for the first hydraulic cylinder 10 the minimum value Q wm_min or the maximum value Q wm_max of the hydraulic oil supply range is reached. Reaching a limit value of the hydraulic oil supply range by the hydraulic oil supply flow rate for each hydraulic cylinder 10 means that a difference between an actual measured value of the hydraulic oil supply flow rate for the hydraulic cylinder 10 (hydraulic oil supply flow rate detected by a flow rate sensor (not shown)) and its limit value is equal to or less than a predetermined threshold.

[0097] When it is determined that the first work item should reach the limit value of the operating range, the prediction unit 562 calculates a drive amount for controlling an operation amount of a second work item to prevent the first work item from approaching the limit value of the operating range.

[0098] The prevention of the first working element from approaching the limit value of the functional range represents that when the determination unit 61 determines that a difference Δθ between the actual angle of the working element and the stroke end angle indicating the end of the stroke of the working element is equal to or smaller than the threshold value, the difference Δθ is prevented from further decreasing at the time the determination is made by the determination unit 61.

[0099] When it is determined that the first working element is approaching the end of the movement range, the prediction unit 562 calculates the drive amount to control an angle of the second working element so as to prevent the first working element from approaching the end of the movement range. For example, when it is determined that the first working element reaches the limit value of the operation range, the prediction unit 562 calculates the drive amount to control the operation amount of the second working element so as to cause the first working element to have a medium operation range. In other words, when it is determined that the first working element is approaching the end of the movement range, the prediction unit 562 calculates the drive amount to control the angle of the second working element so as to prevent the first working element from approaching the end of the movement range.

[0100] When it is determined that the first hydraulic cylinder 10 should reach the limit value of the operating range, the prediction unit 562 calculates a drive amount for controlling an operation amount of a second hydraulic cylinder 10 to prevent the first hydraulic cylinder 10 from approaching the limit value of the operating range.

[0101] The prevention of the first hydraulic cylinder 10 from approaching the limit value of the operating range represents that when the determination unit 61 determines that a difference ΔQ between the actual measured value of the hydraulic oil supply flow rate for the hydraulic cylinder 10 and its limit value is equal to or smaller than the threshold value, the difference ΔQ is prevented from further decreasing at the time point at which the determination is made by the determination unit 61.

[0102] When it is determined that the first hydraulic cylinder 10 should reach the limit value of the operating range, the prediction unit 562 calculates a drive amount to control an operation amount of a second hydraulic cylinder 10 to prevent the first hydraulic cylinder 10 from approaching the limit value of the operating range. In one example, when it is determined that the first hydraulic cylinder 10 should reach the limit value of the operating range, the prediction unit 562 calculates a drive amount to control an operation amount of a second hydraulic cylinder 10 so that the first hydraulic cylinder 10 has a middle operating range. In other words, when it is determined that a hydraulic oil supply flow rate Q wm1 for the first hydraulic cylinder 10 the minimum value Q wm_min or the maximum value Q ym_maxof the hydraulic oil supply range, the prediction unit 562 calculates the drive amount to obtain a hydraulic oil supply flow rate Q wm_m2 for the second hydraulic cylinder 10 so that the hydraulic oil supply flow rate Q wm1 for the first hydraulic cylinder 10 into a middle hydraulic oil supply area Q wm_mid changes.

[0103] Fig. 9 is a diagram showing an example of operation of the excavator 100 according to the present embodiment. Referring to Fig. 9 describes the example in which, when it is determined that the first working element is approaching the end of the movement range, the angle of the second working element is controlled to prevent the first working element from approaching the end of the movement range. In the following description, it is assumed that the first working element is the bucket 8 and the second working element is one or both of the boom 6 and the arm 7.

[0104] The excavator 100 includes the swing body 2 configured to support the work implement 1. The operator operates the operating device 40 to move the bucket 8 from a first position P1 of the construction surface IS to a second position P2 closer to the swing body 2 than the first position P1. The model prediction control unit 56 calculates the prediction value of the position of the cutting edge 9 based on a target value of the position of the cutting edge 9 of the work implement 1 and the prediction model, and calculates the drive amount based on the prediction value to control the work implement 1 so that the cutting edge 9 follows the construction surface IS. The command unit 58 controls the work implement 1 based on the drive amount calculated by the model prediction control unit 56.When the actuating device 40 is actuated to move the bucket 8 from the first position P1 to the second position P2 of the construction surface IS, the bucket 8 approaches as shown in . Fig. 9, gradually approaching the end (the end of the stroke) of the movement range of the blade 8.

[0105] When it is determined by the determination unit 61 that the bucket 8 is approaching the end of the movement range while the operating device 40 that operates the work machine 1 is moving the bucket 8 from the first position P1 to the second position P2, the prediction unit 562 calculates the drive amount to control the angle of one or both of the boom 6 and the arm 7 to prevent the bucket 8 from approaching the end of the movement range. The command unit 58 controls the angle of one or both of the boom 6 and the arm 7 based on the drive amount calculated by the model prediction control unit 56. In the above embodiment, when the bucket 8 is approaching the end of the movement range, the command unit 58 operates the boom 6 to raise to prevent the bucket 8 from approaching the end of the movement range.Note that when the bucket 8 approaches the end of the movement range, the command unit 58 operates the boom 7 to lower to prevent the bucket 8 from approaching the end of the movement range. Therefore, when the bucket 8 is to be moved from the first position P1 to the second position P2, the bucket 8 is prevented from reaching the end of the movement range along the way. Therefore, the bucket 8 can move from the first position P1 to the second position P2. Therefore, it is possible to level the design target between the first position P1 and the second position P2 by a single movement of the bucket 8.

[0106] As mentioned above with reference to Fig. 9, the example was described in which, when it is determined that the first working element is approaching the end of the movement range, the angle of the second working element is controlled to prevent the first working element from approaching the end of the movement range. Next, an example will be described in which, when it is determined that the hydraulic oil supply flow rate Q wm1 for the first hydraulic cylinder 10 the limit value (the minimum value Q wm_min or the maximum value Q mn_max ) of the hydraulic oil supply area, the hydraulic oil supply flow rate Q wm2 for the second hydraulic cylinder 10 is controlled so that the hydraulic oil supply flow rate Q wm1 for the first hydraulic cylinder 10 in the middle hydraulic oil supply area Q wm_midchanges. In the following description of the example, for the sake of simplicity, the flow rate of the hydraulic oil discharged from the hydraulic pump 17 is denoted by Q, and the hydraulic oil discharged from the hydraulic pump 17 is distributed to the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13. Therefore, the flow rate Q is a sum of the hydraulic oil supply flow rate Q bm for the boom cylinder 11, the hydraulic oil supply flow rate Qar for the arm cylinder 12 and the hydraulic oil supply flow rate Q bk for the bucket cylinder 13 (Q = Q bm + Q ar + Q bk ) .

[0107] For example, if it is determined that the hydraulic oil supply flow rate Q bk for the bucket cylinder 13 the maximum value Q bk_max reaches, the prediction unit 562 calculates the drive amount to control one or both of the hydraulic oil supply flow rate Q bmfor the boom cylinder 11 and the hydraulic oil supply flow rate Q ar for the arm cylinder 12 so that the hydraulic oil supply flow rate Q bk for the bucket cylinder 13 into the middle hydraulic oil supply area (so that the hydraulic oil supply flow rate Q bk is reduced). The command unit 58 outputs the control command to the valve device 18 based on the drive amount calculated by the prediction unit 562, so that one or both of the hydraulic oil supply flow rate Q bm for the boom cylinder 11 and the hydraulic oil supply flow rate Q ar for the arm cylinder 12.

[0108] This makes it possible for a state in which only the bucket 8 operates at a high operating speed to transition to a state in which the operating speed of the bucket 8 is lowered and one or both of the boom 6 and the arm 7 operate at a high operating speed. [Tax procedure]

[0109] Fig. Fig. 10 is a flowchart illustrating a control method for the excavator 100 according to the present embodiment. In the present embodiment, the control method is performed during work such as moving the bucket 8 from the first position P1 to the second position P2, as described with reference to Fig. Fig. 9 described, described.

[0110] The construction surface acquisition unit 54 acquires the construction surface data (step S1).

[0111] The position data acquisition unit 51 acquires the position data of the swivel body 2 from the position calculation device 20 as an actual value. Furthermore, the angle data acquisition unit 52 acquires the angle data and angular velocity data of the work implement 1 from the angle detection device 30 as actual values ​​(step S2).

[0112] The driver operates the operating device 40. The operation data acquisition unit 53 acquires the operation data from the operating device 40. The target value generation unit 55 generates the target value of the amount of control of the work machine 1 based on at least the operation data of the operating device 40 (step S3).

[0113] The target value of the amount of control of the working device 1 contains a target value of the travel speed of the bucket 8. The target value of the movement speed of the bucket 8 contains the target translation speed v targetthe blade 8, described with reference to Fig. 6, and the target rotational speed ω target the blade 8, described with reference to Fig. 8. The target value generation unit 55 calculates the target value that represents the target translation speed v target and the target rotational speed ω target of the bucket 8, based on the operation data of the actuator 40, the angle data indicating each angle θ that changes by the operation of the actuator 40, and the angular velocity data indicating the amount of change in each angle θ per unit time, as well as the design surface data.

[0114] The constraint condition calculation unit 57 calculates the first constraint condition related to the power of the excavator 100 and the second constraint condition related to the position of the bucket 8 based on the operation data of the operating device 40, the angle data indicating each angle θ of the work machine 1 that changes due to the operation of the operating device 40, and the angular velocity data indicating the amount of change of each angle θ per unit time, and the design area data (step S4).

[0115] The prediction unit 562 calculates, based on the target value of the amount of control of the work machine 1 and the prediction model stored in the prediction model storage unit 561, the drive amount for controlling the work machine 1 to satisfy the constraint condition calculated in step S5 (step S5).

[0116] The prediction unit 562 calculates the control amount of the working device 1, for example, ten steps in advance from the current time.

[0117] The prediction unit 562 calculates the prediction value of the amount of control of the working device 1 based on the control amount calculated in step S6 and the actual value detected in step S3 (step S6).

[0118] The prediction unit 562 calculates the prediction value of the moving speed of the working device 1 and the prediction value of the position of the cutting edge 9, for example, ten steps in advance from the current time.

[0119] The prediction unit 562 determines, based on the operation data of the actuator 40 that operates the work machine 1, whether a prediction value of a bucket speed calculated so that the cutting edge 9 of the bucket 8 follows the design surface IS exceeds a maximum speed (step S7).

[0120] If it is determined in step S7 that the predicted value of the bucket speed does not exceed the maximum speed (step S7: No), the predicting unit 562 recalculates the control amount so that the predicted value of the control amount follows its target value (step S5).

[0121] The prediction unit 562 recalculates the control amount to minimize the value of the evaluation function defined by the target value and the actual value of the control amount. The prediction unit 562 recalculates the control amount to satisfy the first constraint and the second constraint.

[0122] If it is determined in step S7 that the predicted value of the bucket speed exceeds the maximum speed (step S7: Yes), the determination unit 61 determines whether the bucket 8 is approaching the end of the stroke, that is, the end of the movement range, based on angle data of the bucket 8 acquired by the angle data acquisition unit 52 (step S8).

[0123] If it is determined in step S8 that the bucket 8 is not approaching the end of the stroke (step S8: No), the boom 6 and the arm 7 are driven based on the operation of the actuator 40.

[0124] When it is determined in step S8 that the bucket 8 is approaching the end of the stroke (step S8: Yes), the prediction unit 562 recalculates the control amount for operating the boom 6 to lift in order to prevent the bucket 8 from approaching the end of the movement range (step S5).

[0125] If it is determined in step S8 that the bucket 8 is approaching the end of the stroke (step S8: Yes), the prediction unit 562 determines whether the evaluation function has the minimum value (step S9).

[0126] The speed of the bucket 8 may be the angular velocity or angular acceleration of each axis of the work implement 1 or the swing body 2. The maximum speed may be an upper limit. In other words, in step S8, the prediction unit 562 may determine whether a prediction value of the angular acceleration of each axis exceeds the upper limit angular acceleration.

[0127] If it is determined in step S9 that the evaluation function does not have the minimum value (step S9: No), the prediction unit 562 recalculates the control amount so that the prediction value of the amount of control follows the target value (step S5).

[0128] The prediction unit 562 repeats the processing of step S5, step S6, step S7, step S8, and step S9 until the evaluation function has the minimum value.

[0129] When it is determined in step S9 that the evaluation function has the minimum value (step S9: Yes), the command unit 58 outputs the control command for controlling the work machine 1 based on the drive amount for controlling the work machine 1 calculated in step S6 (step S10).

[0130] As described above, the control amount is calculated, for example, ten steps ahead from the current time. Command unit 58 outputs the control amount calculated in the first step from the control amounts calculated ten steps ahead as a control command.

[0131] Therefore, as with reference to Fig. As described in Figure 9, the bucket 8 moving from the first position P1 to the second position P2 is prevented from reaching the end of the stroke along the way. Therefore, the bucket 8 can move from the first position P1 to the second position P2. Therefore, it is possible to level the design target between the first position P1 and the second position P2 with a single movement of the bucket 8. [Effects]

[0132] As described above, the model prediction control of the work machine 1 of the present embodiment enables the control device 50 to control the work machine 1 so that the bucket 8 follows the construction surface regardless of the condition on the construction site, which may change variously.

[0133] For example, as described above, when the bucket 8 is moved from the first position P1 to the second position P2 to level the construction target, the bucket 8 may reach the end of its stroke before the bucket 8 reaches the second position P2. This may make it possible to level the ground with a single operation of the bucket 8. Furthermore, if the bucket 8 is forcibly moved to the second position P2, it may dig beneath the construction surface.

[0134] In the present embodiment, the model prediction control of the work machine 1 can cause the work machine 1 to follow the construction surfaces even when construction surfaces of different shapes are set on the construction site or even when work with different contents is required on the construction site. Therefore, it is possible to bring the construction target into a desired shape while suppressing a decrease in work efficiency.

[0135] Fig. 11 is a graph showing a result of the comparison between the control of the working device 1 by the control method according to the present embodiment and the control of the working device 1 by a control method according to a comparative example. Fig. In the graph shown in Figure 11, the horizontal axis represents time and the vertical axis represents the distance between the cutting edge and the construction surface. Fig. Figure 11 illustrates the distance between the cutting edge and the construction surface when the blade 8 is moved from the first position P1 to the second position P2, as described with reference to Fig. 9 described.

[0136] In Fig. In FIG. 11, a line La shows the control result of the work machine 1 controlled by the control method according to the present embodiment, and a line Lb shows the control result of the work machine 1 controlled by the control method according to the comparative example. The control method according to the comparative example is a control method in which feedback control is performed based only on the angle data of the work machine 1 without performing model prediction control.

[0137] As in Fig. 11, the control method according to the present embodiment allows the bucket 8 to move along the construction surface from the first position P1 to the second position P2 without digging below the construction surface.

[0138] When the bucket 8 approaches the second position P2, the bucket 8 reaches the end of the stroke and no longer follows the construction surface IS, so that the bucket 8 digs below the construction surface IS and prevents the construction of the construction target into the desired shape.

[0139] As described above, the model prediction control of the work machine 1 according to the present embodiment enables the control device 50 to appropriately control the work machine 1 so that the bucket 8 moves along the design surface. [computer system]

[0140] Fig.12 is a block diagram showing an example of a computer system 1000 according to the present embodiment. The above-described control device 50 includes the computer system 1000. The computer system 1000 includes a processor 1001 such as a central processing unit (CPU), a main memory 1002 including non-volatile memory such as read-only memory (ROM) and volatile memory such as random access memory (RAM), a memory 1003, and an interface 1004 including an input / output circuit. The above-described functions of the control device 50 are stored in the memory 1003 as programs. The processor 1001 reads a program from the memory 1003, loads the program into the main memory 1002, and executes the above-described processing according to the program. Note that the programs can be distributed to the computer system 1000 via a network.

[0141] The computer system 1000 is configured to calculate the predicted value of the amount of control of the work device 1 based on the target value of the amount of control of the work device 1 and the predicted model for the work device 1, calculate the control amount for controlling the work device 1 based on the predicted value, and output the control command for controlling the work device 1 based on the control amount. [Other embodiments]

[0142] In the embodiments described above, the target value generation unit 55 is configured to use the speed (translation speed and rotation speed) of the blade 8 to generate the target value for the model prediction control unit 56. The target value generation unit 55 may use the position and attitude of the blade 8 to generate the target value for the model prediction control unit 56.

[0143] Note that in the above-described embodiments, some or all of the functions of the control device 50 may be provided in an external computer system for the excavator 100. For example, the target value generation unit 55 and the model prediction control unit 56 may be provided in the external computer system, so that the control amount calculated by the external computer system is transmitted to the excavator 100 via a wireless communication system.

[0144] Note that in the above-described embodiments, the construction machine 100 is the excavator. The component elements described in the above embodiments are applicable to a construction machine with a work implement other than the excavator.

[0145] Note that in the embodiments described above, the swing motor 16 configured to swing the swing body 2 does not have to be the hydraulic motor. The swing motor 16 may be an electric motor configured to be driven by the power supply. Furthermore, the working device 1 may be driven not by the hydraulic cylinder 10, but by the power generated by an electric actuator, such as an electric motor. List of reference symbols 1 WORKING DEVICE 2 swivel bodies 3 DRIVING BODY 3C CATERPILLAR 4 CABINS 4 SEATS 5 ENGINE 6 booms 7 ARM 8 SHOVEL 9 CUTTING EDGE 10 hydraulic cylinders 11 BOOM CYLINDERS 12 arm cylinders 13 bucket cylinders 14 TILT CYLINDERS 15 ROTARY CYLINDERS 16 SWIVEL MOTOR 17 HYDRAULIC PUMP 18 VALVE DEVICE 20 POSITION CALCULATION DEVICE 21 POSITION CALCULATORS 22 STORAGE CALCULATORS 23 ORIENTATION CALCULATOR 30 ANGLE DETECTION DEVICE 31 BOOM ANGLE DETECTOR 32 ARM ANGLE DETECTOR 33 BLADE ANGLE DETECTOR 34 Tilt Angle Detector 35 ROTATION ANGLE DETECTOR 40 ACTUATOR 41 RIGHT CONTROL LEVER 42 LEFT CONTROL LEVER 43 Tilt control lever 50 CONTROL DEVICE 51 POSITION DATA ACQUISITION DEVICE 52 ANGLE DATA ACQUISITION UNIT 53 ACTUATING DATA ACQUISITION UNIT 54 Construction Area Recording Unit 55 TARGET PRODUCTION UNIT 56 MODEL PREDICTION CONTROLLER 57 BOUNDARY CONDITION CALCULATION UNIT 58 COMMAND UNIT 60 STORAGE UNIT 61 UNIT OF DETERMINATION 70 DESIGN SURFACE DATA FEEDING DEVICE 100 CONSTRUCTION MACHINERY 200 CONTROL SYSTEM 551 Target Translation Speed ​​Calculation Unit 551A TRANSLATION SPEED CALCULATION UNIT 551B Speed ​​Limit Calculation Unit 551C PI CONTROL UNIT 551D DELAY PROCESSING UNIT 552 Target rotation speed calculation unit 552A ACTUAL POSITION CALCULATION UNIT 552B Target Position Calculation Unit 552C ROTATIONAL SPEED CALCULATION UNIT 552D P-CONTROL UNIT 561 PREDICTION MODEL STORAGE UNIT 562 FORECAST UNIT AX1 BOOM AXLE AX2 ARM AXLE AX3 BLADE AXLE AX4 TILT AXIS AX5 ROTATION AXIS

Claims

[1] Control system (200) for a construction machine (100) comprising a working device (1), the control system (200) comprising: a target value generation unit (55) configured to generate a target value of an amount of control of the working device (1); a prediction unit (562) configured to calculate a prediction value of the amount of control of the working device (1) based on the target value and a prediction model for the working device (1), and to calculate a control amount for controlling the working device (1) based on the prediction value; and a command unit (58) configured to issue a control command for controlling the working device (1) based on the control amount, wherein the construction machine (100) contains a plurality of devices having the same or similar functions, wherein the prediction unit (562) calculates a prediction value of an operation amount of each of the devices in a functional area of ​​the respective device based on the target value and the prediction model, wherein the control system (200) includes a determination unit (61) configured to determine whether a first device of the devices reaches a limit value of its functional range, and wherein the prediction unit (562) calculates a drive amount to control the operation amount of a second device of the devices to prevent the first device of the devices from approaching the limit value of its operating range when it is determined that the first device of the devices should reach the limit value of its operating range. [2] Control system (200) for a construction machine (100) according to claim 1, wherein the working device (1) contains a plurality of working elements which are movable relative to one another, the devices containing the working elements, and the respective functional area contains a movement area of ​​the respective work elements. [3] Control system (200) for a construction machine (100) according to claim 1 or 2, wherein the construction machine (100) contains a plurality of hydraulic actuators (10), the devices contain the hydraulic actuators (10), and the respective functional area contains a hydraulic oil supply area defined for the respective hydraulic actuators (10). [4] Control system (200) for a construction machine (100) comprising a working device (1), the control system (200) comprising: a target value generation unit (55) configured to generate a target value of an amount of control of the working device (1); a prediction unit (562) configured to calculate a prediction value of the amount of control of the working device (1) based on the target value and a prediction model for the working device (1), and to calculate a control amount for controlling the working device (1) based on the prediction value; and a command unit (58) configured to issue a control command for controlling the working device (1) based on the control amount, wherein the working device (1) contains a plurality of working elements movable relative to one another, the prediction unit (562) calculates a prediction value of an angle of each of the work elements in a movement range of the respective work element based on the target value and the prediction model, the control system (200) includes a determination unit (61) configured to determine whether a first working element of the working elements is approaching an end of its range of motion, and the prediction unit (562) calculates a drive amount to control an angle of a second working element of the working elements to prevent the first working element of the working elements from approaching the end of its movement range when it is determined that the first working element of the working elements is approaching the end of its movement range. [5] Control system (200) for a construction machine (100) according to claim 4, wherein the working device (1) comprises a boom (6), an arm (7) and a bucket (8), the first working element of the working elements contains the blade (8), the second working element of the working elements includes one or both of the boom (6) and the arm (7), the construction machine (100) includes a swivel body (2) which is designed to support the working device (1), and the prediction unit (562) calculates a control amount to control, by an actuating device (40) configured to actuate the work implement (1), an angle of one or both of the boom (6) and the arm (7) to prevent the bucket (8) from approaching the end of its movement range when it is determined that the bucket (8) is approaching the end of its movement range while the bucket (8) is being moved from a first position to a second position that is closer to the swing body (2) than the first position. [6] Control system (200) for a construction machine (100) according to claim 4 or 5, wherein the construction machine (100) includes a plurality of hydraulic actuators (10) configured to actuate a plurality of the working elements, respectively, the prediction unit (562) calculates a prediction value of a hydraulic oil supply flow rate for each of the hydraulic actuators (10) in a hydraulic oil supply range defined for the respective hydraulic actuator (10) based on the target value and the prediction model, the control system (200) includes a determination unit (61) configured to determine whether a hydraulic oil supply flow rate for a first hydraulic actuator of the hydraulic actuators reaches a limit value of its hydraulic oil supply range, and the prediction unit (562) calculates a drive amount to control a hydraulic oil supply flow rate for a second hydraulic actuator of the hydraulic actuators to prevent a hydraulic oil supply flow rate for the first hydraulic actuator of the hydraulic actuators from approaching the limit value of its hydraulic oil supply range when it is determined that the hydraulic oil supply flow rate for the first hydraulic actuator should reach the limit value of its hydraulic oil supply range. [7] Control system (200) for a construction machine (100) according to one of claims 1 to 6, comprising an actuation data acquisition unit (53) configured to acquire actuation data of an actuation device (40) configured to actuate the working device (1), wherein the target value generating unit (55) generates the target value based on the operation data. [8] Control system (200) for a construction machine (100) according to one of claims 1 to 7, comprising a construction surface detection unit (54) configured to detect a construction surface (IS) indicating a target shape of a construction target, wherein the amount of control includes a position of a predetermined portion (9) of the implement (1), and the prediction unit (562) calculates the control amount on the basis of the prediction value and the construction area (IS) so that a distance between the predetermined section (9) of the working device (1) and the construction area (IS) is maintained. [9] A control system (200) for a construction machine (100) according to any one of claims 1 to 8, wherein the amount of control includes a movement speed of the work implement (1). [10] The control system (200) for a construction machine (100) according to any one of claims 1 to 9, wherein the prediction unit (562) calculates the control amount such that the prediction value of the amount of control follows the target value. [11] The control system (200) for a construction machine (100) according to any one of claims 1 to 10, wherein the prediction unit (562) calculates the control amount so that a value of an evaluation function defined by the target value and the prediction value of the control amount is minimized. [12] Control system (200) for a construction machine (100) according to claim 11, comprising a boundary condition calculation unit (57) configured to calculate a first boundary condition relating to the performance of the construction machine (100) and a second boundary condition relating to a position of the working device (1), wherein the prediction unit (562) calculates the control amount to satisfy the first constraint condition and the second constraint condition. [13] Construction machine (100), comprising: a pivoting body (2) adapted to support a working device (1); and the control system (200) for a construction machine (100) according to one of claims 1 to 12. [14] Control method for a construction machine (100) comprising a working device (1) and a plurality of devices having the same or similar functions, comprising: Generating a target value of an amount of control of the working device (1); Calculating a predicted value of an amount of control of the work device (1) based on a target value of the amount of control of the work device (1) and a predictive model for the work device (1); Calculating a control amount for controlling the working device (1) based on the prediction value; Outputting a control command for controlling the working device (1) based on the control amount; Calculating a predicted value of an operation amount of each of the devices in a functional area of ​​the respective device based on the target value and the predictive model, Determining whether a first device of the devices reaches a limit of its functional range, and Calculating a drive amount to control the operation amount of a second device of the devices to prevent the first device of the devices from approaching the limit of its operating range when it is determined that the first device of the devices should reach the limit of its operating range.

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