Machine control device, construction machine, construction machine control system, construction machine control method, and program

Abstract

A machine control device (50) is configured to: determine a bucket target speed, which is a target value for the speed of a bucket (6), by using movable part operation information relating to the operation of a movable part (5); determine a bucket assist operation amount via feedback control based on the deviation between the bucket target speed and the speed of the bucket (6); and control the operation of the bucket (6) on the basis of the bucket assist operation amount.

Description

Mechanical control device, construction machine, construction machine control system, construction machine control method, and program

[0001] The present disclosure relates to technology for construction machinery such as excavators.

[0002] Patent Document 1 discloses a technology related to construction machinery. The control device for this construction machinery measures or calculates a motion state quantity of the combined center of gravity of a plurality of members, determines an instruction value for an operation mechanism of a work implement using feedback control such that the motion state quantity follows a predetermined first target value, and adjusts an operation amount of an operator with respect to the work implement based on the instruction value.

[0003] One of the objects of the present disclosure is to operate a bucket at a speed suitable for work such as excavation work and grading work.

[0004] Japanese Patent No. 7146530

[0005] An object of the present disclosure is to provide a mechanical control device, a construction machine, a construction machine control system, a construction machine control method, and a program that can operate a bucket of a construction machine at a speed suitable for work such as excavation work and grading work.

[0006] A mechanical control device according to an aspect of the present disclosure is a mechanical control device for controlling an operation of a construction machine including a lower traveling structure, an upper revolving structure rotatably supported by the lower traveling structure, and a work implement that includes a movable portion and a bucket and is rotatably supported by the upper revolving structure. The mechanical control device is configured to: determine a target bucket speed that is a target value of the speed of the bucket using movable portion operation information that is information related to the operation of the movable portion; determine a bucket assist operation amount by feedback control based on a deviation between the target bucket speed and the speed of the bucket; and control the operation of the bucket based on the bucket assist operation amount.

[0007] Figure 1 is a side view showing a construction machine equipped with a machine control device according to the first or second embodiment. Figure 2 is a block diagram showing an example of bucket assist control performed by the machine control device according to the first embodiment. Figure 3 is a flowchart showing an example of calculation processing performed by the machine control device according to the first embodiment. Figure 4 is a diagram showing an example of the conditions for switching the bucket assist control on and off by the machine control device according to the first or second embodiment. Figure 5 is a block diagram showing an example of boom assist control performed by the machine control device according to the second embodiment. Figure 6 is a flowchart showing an example of calculation processing performed by the machine control device according to the second embodiment. Figure 7 is a diagram showing a construction machine control system equipped with the machine control device.

[0008] The machine control device 50 and construction machine 100 according to the embodiments of this disclosure will be described with reference to the drawings. Note that the following embodiments are examples that embody this disclosure and are not intended to limit the technical scope of this disclosure.

[0009] Figure 1 is a perspective view showing a construction machine 100 equipped with a machine control device 50 according to this embodiment. This construction machine 100 is placed at a work site and performs various tasks such as excavation work at the work site. The construction machine 100 according to this embodiment is a shovel.

[0010] The construction machine 100 comprises a self-propelled lower traveling body 1, an upper rotating body 2 supported by the lower traveling body 1 so as to be able to rotate relative to the lower traveling body 1 around a vertically extending pivot axis Z, a work device 3 supported by the upper rotating body 2, and a plurality of actuators.

[0011] The lower running body 1 comprises a pair of left and right crawler running devices and a lower frame supported by these crawler running devices.

[0012] The upper rotating body 2 comprises a rotating frame 2A, a cab 2B, and a rear outer wall 2C. The rotating frame 2A is a frame that is rotatably supported by the lower traveling body 1 and constitutes the base portion of the upper rotating body 2.

[0013] The cab 2B is located, for example, at the front left of the slewing frame 2A. Inside the cab 2B are the driver's seat, control devices 30, etc. (not shown in the diagram).

[0014] The rear outer wall 2C is located behind the cab 2B and is an outer wall that defines the machine room. Various equipment such as power equipment, hydraulic equipment such as a hydraulic pump 60, and electrical equipment are arranged in the machine room. The power equipment may be an engine, a battery, or a generator. The hydraulic pump 60 is configured to be driven by the power equipment to discharge hydraulic fluid.

[0015] The working device 3 includes a boom 4 rotatably supported relative to the upper slewing body 2 around a pivot axis extending in the left-right direction, an arm 5 rotatably supported relative to the boom 4 around a pivot axis extending in the left-right direction, and a bucket 6 rotatably supported relative to the arm 5 around a pivot axis extending in the left-right direction. The arm 5 is an example of a movable part in this disclosure.

[0016] The boom 4 has a boom base end 4a, which is the base end of the boom 4 and is rotatably attached to the upper slewing body 2, and a boom tip end 4b, which is the tip end of the boom 4. The arm 5 has an arm base end 5a, which is the base end of the arm 5 and is rotatably attached to the boom tip end 4b, and an arm tip end 5b, which is the tip end of the arm 5. The bucket 6 has a bucket base end 6a, which is the base end of the bucket 6 and is rotatably attached to the arm tip end 5b, and a bucket tip end 6b, which is the tip end of the bucket 6.

[0017] In the drawings, the front-rear direction is based on the orientation of the upper rotating body 2. Specifically, the front is the horizontal direction in which the working device 3 extends from the boom base end 4a when viewing the construction machine 100 from directly above. The rear is the opposite direction to the front. The left-right direction is the horizontal direction perpendicular to the front-rear direction.

[0018] Each of the plurality of actuators operates by receiving a supply of hydraulic fluid discharged from the hydraulic pump 60. The plurality of actuators includes a plurality of hydraulic cylinders and a plurality of hydraulic motors. The plurality of hydraulic cylinders include a boom cylinder 11 for rotating the boom 4, an arm cylinder 12 for rotating the arm 5, and a bucket cylinder 13 for rotating the bucket 6. The plurality of hydraulic motors include a slewing motor 14 for slewing the upper slewing body 2 relative to the lower traveling body 1, and left and right traveling motors 15 for traveling the lower traveling body 1.

[0019] Figure 2 is a block diagram showing an example of bucket assist control performed by the machine control device 50. As shown in Figures 1 and 2, the construction machine 100 includes an operation information detector 20, an operating device 30, a control valve 40, and a machine control device 50. Bucket assist control will be described later.

[0020] The motion information detector 20 detects motion information, which is information relating to the operation of the work device 3, and inputs the detection result to the machine control device 50. This allows the machine control device 50 to acquire motion information relating to the operation of the work device 3. The motion information detector 20 may include a boom motion information detector, an arm motion information detector, and a bucket motion information detector.

[0021] The boom motion information detector, arm motion information detector, and bucket motion information detector each input their detection results to the machine control device 50. This allows the machine control device 50 to acquire boom motion information, which is information regarding the movement of the boom 4; arm motion information, which is information regarding the movement of the arm 5; and bucket motion information, which is information regarding the movement of the bucket 6. Arm motion information is an example of movable part motion information in this disclosure.

[0022] The boom motion information includes at least one of boom posture information, which is information about the attitude of boom 4, and boom speed information, which is information about the speed of boom 4. The arm motion information includes at least one of arm posture information, which is information about the attitude of arm 5, and arm speed information, which is information about the speed of arm 5. The bucket motion information includes at least one of bucket posture information, which is information about the attitude of bucket 6, and bucket speed information, which is information about the speed of bucket 6.

[0023] Specifically, the boom motion information detector may include a boom attitude sensor 21, the arm motion information detector may include an arm attitude sensor 22, and the bucket motion information detector may include a bucket attitude sensor 23.

[0024] The boom attitude sensor 21 may be a sensor that detects the attitude of the boom 4, or it may be a sensor that detects the state of the boom cylinder 11 that is correlated with the attitude of the boom 4 (for example, the length of the boom cylinder 11). The attitude of the boom 4 may be the angle of the boom 4 with respect to the horizontal plane, the angle of the boom 4 with respect to the upper slewing body 2, or the angle of the boom 4 with respect to another reference.

[0025] The arm attitude sensor 22 may be a sensor that detects the attitude of the arm 5, or it may be a sensor that detects the state of the arm cylinder 12 (for example, the length of the arm cylinder 12) which is correlated with the attitude of the arm 5. The attitude of the arm 5 may be the angle of the arm 5 with respect to the horizontal plane, the angle of the arm 5 with respect to the boom 4, or the angle of the arm 5 with respect to another reference.

[0026] The bucket attitude sensor 23 may be a sensor that detects the attitude of the bucket 6, or it may be a sensor that detects the state of the bucket cylinder 13 (for example, the length of the bucket cylinder 13) which is correlated with the attitude of the bucket 6. The attitude of the bucket 6 may be the angle of the bucket 6 with respect to the horizontal plane, the angle of the bucket 6 with respect to the arm 5, or the angle of the bucket 6 with respect to another reference.

[0027] Each of the boom attitude sensor 21, arm attitude sensor 22, and bucket attitude sensor 23 may include, for example, a sensor for detecting the rotation angle, a sensor for detecting the degree of extension or retraction of the cylinder, or a sensor for detecting the inclination angle with respect to a reference such as a horizontal plane. Specifically, each of the boom attitude sensor 21, arm attitude sensor 22, and bucket attitude sensor 23 may include, for example, an inertial measuring unit (IMU), a sensor such as a rotary encoder, resolver, or potentiometer for detecting the rotation angle, or other sensors capable of detecting attitude.

[0028] The machine control device 50 can calculate the posture of the boom 4, the posture of the arm 5, and the posture of the bucket 6 at that moment based on the detection results that are sequentially input from the boom posture sensor 21, the arm posture sensor 22, and the bucket posture sensor 23. In addition, the machine control device 50 can calculate the speed of the boom 4 based on the change in the posture of the boom 4, the speed of the arm 5 based on the change in the posture of the arm 5, and the speed of the bucket 6 based on the change in the posture of the bucket 6.

[0029] The speed of the boom 4 may be the angular velocity of the boom 4 relative to the upper slewing body 2, the extension / retraction speed of the boom cylinder 11 which is correlated with the angular velocity of the boom 4, or any other speed which is correlated with the angular velocity of the boom 4. The speed of the arm 5 may be, for example, the angular velocity of the arm 5 relative to the boom 4, the extension / retraction speed of the arm cylinder 12 which is correlated with the angular velocity of the arm 5, or any other speed which is correlated with the angular velocity of the arm 5. The speed of the bucket 6 may be, for example, the angular velocity of the bucket 6 relative to the arm 5, the extension / retraction speed of the bucket cylinder 13 which is correlated with the angular velocity of the bucket 6, or any other speed which is correlated with the angular velocity of the bucket 6.

[0030] The operating device 30 includes a plurality of operating levers that are operated by an operator. The operator's operations include boom operation for rotating the boom 4, arm operation for rotating the arm 5, bucket operation for rotating the bucket 6, slewing operation for slewing the upper slewing body 2 relative to the lower traveling body 1, and traveling operation for moving the lower traveling body 1. The operating device 30 is located inside the cab 2B of the construction machine 100.

[0031] The boom operation consists of either a boom raising operation, which rotates the boom 4 in the boom raising direction around the boom base end 4a, or a boom lowering operation, which rotates the boom 4 in the boom lowering direction around the boom base end 4a. The boom raising direction is the direction in which the boom 4 rotates so that the boom tip 4b moves away from the ground, and the boom lowering direction is the direction in which the boom 4 rotates so that the boom tip 4b moves closer to the ground.

[0032] The arm operation consists of either an arm pulling operation, which rotates the arm 5 in the arm pulling direction around the arm base end 5a, or an arm pushing operation, which rotates the arm 5 in the arm pushing direction around the arm base end 5a. The arm pulling direction is the direction in which the arm 5 rotates so that the arm tip 5b moves closer to the upper slewing body 2, and the arm pushing direction is the direction in which the arm 5 rotates so that the arm tip 5b moves away from the upper slewing body 2.

[0033] Bucket operation consists of either a bucket pulling operation, which rotates the bucket 6 in the bucket pulling direction around the bucket base end 6a, or a bucket pushing operation, which rotates the bucket 6 in the bucket pushing direction around the bucket base end 6a. The bucket pulling direction (bucket excavation direction) is the direction in which the bucket 6 rotates so that the bucket tip 6b approaches the upper rotating body 2, and the bucket pushing direction (bucket soil discharge direction) is the direction in which the bucket 6 rotates so that the bucket tip 6b moves away from the upper rotating body 2.

[0034] The turning operation is either a right-turn operation to turn the upper turning body 2 to the right relative to the lower traveling body 1, or a left-turn operation to turn the upper turning body 2 to the left relative to the lower traveling body 1. The traveling operation includes a right-travel operation to activate the right crawler traveling device, and a left-travel operation to activate the left crawler traveling device.

[0035] When the operating device 30 receives a boom-raising operation from an operator, it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (boom operator operation amount), which is the amount of the boom-raising operation. When the operating device 30 receives a boom-lowering operation from an operator, it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (boom operator operation amount), which is the amount of the boom-lowering operation.

[0036] When the operating device 30 receives an arm pulling operation from an operator, it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (arm operator operation amount), which is the amount of the arm pulling operation. When the operating device 30 receives an arm pushing operation from an operator, it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (arm operator operation amount), which is the amount of the arm pushing operation.

[0037] When the operating device 30 receives a bucket pulling operation from an operator, it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (bucket operator operation amount), which is the amount of the bucket pulling operation. When the operating device 30 receives a bucket pushing operation from an operator, it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (bucket operator operation amount), which is the amount of the bucket pushing operation.

[0038] When the operating device 30 receives a turning operation or a traveling operation, it also inputs an operation signal to the machine control device 50 corresponding to the operator operation amount, which is the amount of the operation, in the same manner as described above.

[0039] The control valve 40 is configured to adjust the direction and flow rate of the hydraulic fluid supplied to each of the plurality of actuators. The control valve 40 includes a boom control mechanism 41, an arm control mechanism 42, a bucket control mechanism 43, a slewing control mechanism 44, and a travel control mechanism 45.

[0040] The boom control mechanism 41 may include a directional control valve for controlling the direction and flow rate of the hydraulic fluid supplied to the boom cylinder 11. The arm control mechanism 42 may include a directional control valve for controlling the direction and flow rate of the hydraulic fluid supplied to the arm cylinder 12. The bucket control mechanism 43 may include a directional control valve for controlling the direction and flow rate of the hydraulic fluid supplied to the bucket cylinder 13. The slewing control mechanism 44 may include a directional control valve for controlling the direction and flow rate of the hydraulic fluid supplied to the slewing motor 14. The travel control mechanism 45 may include a directional control valve for controlling the direction and flow rate of the hydraulic fluid supplied to the travel motor 15.

[0041] When the boom control mechanism 41 receives a boom raising control command (e.g., current value) from the machine control device 50, it operates to supply a flow rate of hydraulic fluid corresponding to the boom raising control command to the head chamber of the boom cylinder 11 and to allow the hydraulic fluid to be discharged from the rod chamber of the boom cylinder 11. As a result, the boom cylinder 11 extends and the boom 4 performs a boom raising operation. The boom raising operation is an operation in which the boom 4 rotates around the boom base end 4a, causing the boom tip 4b to move away from the ground.

[0042] When the boom control mechanism 41 receives a boom lowering control command (e.g., current value) from the machine control device 50, it operates to supply hydraulic fluid at a flow rate corresponding to the boom lowering control command to the rod side chamber of the boom cylinder 11 and to allow the hydraulic fluid to be discharged from the head side chamber of the boom cylinder 11. As a result, the boom cylinder 11 retracts and the boom 4 performs a boom lowering operation. The boom lowering operation is an operation in which the boom 4 rotates around the boom base end 4a, causing the boom tip 4b to move in a direction that brings it closer to the ground.

[0043] When an arm crowding control command (for example, a current value) is input from the machine control device 50 to the arm control mechanism 42, the arm control mechanism 42 operates to allow hydraulic oil at a flow rate corresponding to the arm crowding control command to be supplied to the head-side chamber of the arm cylinder 12, and allow hydraulic oil to be discharged from the rod-side chamber of the arm cylinder 12. As a result, the arm cylinder 12 extends, and the arm 5 performs an arm crowding operation. The arm crowding operation is an operation in which the arm 5 rotates around the arm base end portion 5a, so that the arm distal end portion 5b moves in a direction approaching the upper revolving superstructure 2.

[0044] When an arm dumping control command (for example, a current value) is input from the machine control device 50 to the arm control mechanism 42, the arm control mechanism 42 operates to allow hydraulic oil at a flow rate corresponding to the arm dumping control command to be supplied to the rod-side chamber of the arm cylinder 12, and allow hydraulic oil to be discharged from the head-side chamber of the arm cylinder 12. As a result, the arm cylinder 12 contracts, and the arm 5 performs an arm dumping operation. The arm dumping operation is an operation in which the arm 5 rotates around the arm base end portion 5a, so that the arm distal end portion 5b moves in a direction away from the upper revolving superstructure 2.

[0045] When a bucket crowding control command (for example, a current value) is input from the machine control device 50 to the bucket control mechanism 43, the bucket control mechanism 43 operates to allow hydraulic oil at a flow rate corresponding to the bucket crowding control command to be supplied to the head-side chamber of the bucket cylinder 13, and allow hydraulic oil to be discharged from the rod-side chamber of the bucket cylinder 13. As a result, the bucket cylinder 13 extends, and the bucket 6 performs a bucket crowding operation (bucket excavation operation). The bucket crowding operation is an operation in which the bucket 6 rotates around the bucket base end portion 6a, so that the bucket distal end portion 6b moves in a direction approaching the upper revolving superstructure 2.

[0046] When a bucket push control command (e.g., a current value) is input from the machine control device 50 to the bucket control mechanism 43, hydraulic oil at a flow rate corresponding to the bucket push control command is supplied to the rod-side chamber of the bucket cylinder 13, and the bucket control mechanism 43 operates to allow hydraulic oil to be discharged from the head-side chamber of the bucket cylinder 13. As a result, the bucket cylinder 13 contracts, and the bucket 6 performs a bucket pushing operation (bucket earth discharging operation). The bucket pushing operation is an operation in which the bucket 6 rotates about the bucket base end portion 6a, thereby moving the bucket tip end portion 6b in a direction away from the upper rotating structure 2.

[0047] The respective directional control valves of the boom control mechanism 41, the arm control mechanism 42, and the bucket control mechanism 43 may be electromagnetic directional control valves that have a pair of solenoids and operate when a control command (e.g., a current value) from the machine control device 50 is input to any one of these solenoids. Further, the respective directional control valves of the boom control mechanism 41, the arm control mechanism 42, and the bucket control mechanism 43 may be pilot pressure type directional control valves that have a pair of pilot ports and operate when pilot pressure is supplied to any one of these pilot ports. When the directional control valve is a pilot pressure type directional control valve, each of the boom control mechanism 41, the arm control mechanism 42, and the bucket control mechanism 43 may include a pair of electromagnetic proportional valves that adjust the pilot pressure supplied to the pair of pilot ports of the directional control valve. In this case, a control command (e.g., a current value) from the machine control device 50 is input to one of the pair of electromagnetic proportional valves.

[0048] Each of the swing control mechanism 44 and the travel control mechanism 45 has the same configuration as the above-described boom control mechanism 41, arm control mechanism 42, and bucket control mechanism 43, so detailed description thereof will be omitted.

[0049] The machine control device 50 includes a computer having an arithmetic processing unit and a memory. The arithmetic processing unit may include, for example, at least one of a CPU (central processing unit), an MPU (micro processing unit), and a GPU (graphics processing unit).

[0050] As shown in Figure 2, the machine control device 50 includes a target speed generation unit 51, a speed calculation unit 52, an assist operation amount calculation unit 53 (PID controller), and a high-level selection unit 54. The functions of the target speed generation unit 51, the speed calculation unit 52, the assist operation amount calculation unit 53, and the high-level selection unit 54 are realized by the calculation processing unit executing a program pre-stored in the memory.

[0051] The target speed generation unit 51 uses the arm motion information, which is information related to the movement of the arm 5, to determine the target bucket speed, which is the target value of the bucket speed 6.

[0052] The speed calculation unit 52 calculates the speed of the arm 5 and the speed of the bucket 6 based on the operation information related to the operation of the work device 3 acquired from the operation information detector 20. The speed calculation unit 52 may further calculate the speed of the boom 4 based on the operation information.

[0053] The assist operation amount calculation unit 53 calculates a bucket speed deviation, which is the difference between the target bucket speed determined by the target speed generation unit 51 and the speed of the bucket 6 (actual speed of the bucket 6) calculated by the speed calculation unit 52, and determines the bucket assist operation amount through feedback control based on the bucket speed deviation. In other words, the assist operation amount calculation unit 53 uses feedback control to determine the bucket assist operation amount to assist the movement of the bucket 6 so that the speed of the bucket 6 follows the target bucket speed. The machine control device 50 controls the movement of the bucket 6 based on the bucket assist operation amount.

[0054] The assist operation amount calculation unit 53 stores a calculation formula that has been pre-designed for feedback control to bring the bucket speed deviation between the bucket target speed and the speed of bucket 6 closer to zero. The feedback control may be PID control, PI control, PD control, or P control.

[0055] The high-level selection unit 54 controls the operation of the bucket 6 based on the larger of the bucket assist operation amount and the operator operation amount, which is a value corresponding to the bucket operation by the operator.

[0056] The machine control device 50 performs assist control to assist the operator operating the construction machine 100 during excavation work. The assist control includes bucket assist control to operate the bucket 6 at a speed suitable for excavation work. In addition, when assist control is not performed, the machine control device 50 performs normal control (non-assist control) to control the operation of the construction machine 100 in accordance with the operation of the operator operating the construction machine 100.

[0057] In bucket assist control mode, the machine control device 50 controls the movement of the bucket 6 based on the bucket assist operation amount, and in normal control mode, it controls the movement of the bucket 6 based on the bucket operator operation amount. Specifically, it is as follows.

[0058] In normal control, the machine control device 50 inputs control commands to the control valve 40 in response to operations such as boom operation, arm operation, bucket operation, slewing operation, and travel operation received from the operator by the operating device 30. As a result, the construction machine 100 performs operations in accordance with the operations performed by the operator.

[0059] Specifically, in normal control, when the operating device 30 receives a boom operation (boom raising operation or boom lowering operation), it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (boom operator operation amount), which is the amount of boom operation. The machine control device 50 then inputs a boom control command (boom raising control command or boom lowering control command) corresponding to the input operation signal to the boom control mechanism 41 of the control valve 40, and the boom control mechanism 41 operates according to the boom control command. As a result, the boom cylinder 11 and the boom 4 perform operations according to the boom operator operation amount.

[0060] In normal control, when the operating device 30 receives an arm operation (arm pulling operation or arm pushing operation), it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (arm operator operation amount), which is the amount of the arm operation. The machine control device 50 then inputs an arm control command (arm pulling control command or arm pushing control command) corresponding to the input operation signal to the arm control mechanism 42 of the control valve 40, and the arm control mechanism 42 operates according to the arm control command. As a result, the arm cylinder 12 and the arm 5 perform operations according to the arm operator operation amount.

[0061] In normal control, when the operating device 30 receives a bucket operation (bucket pulling operation or bucket pushing operation), it inputs an operation signal to the machine control device 50 corresponding to the operator operation amount (bucket operator operation amount), which is the amount of the bucket operation. The machine control device 50 then inputs a bucket control command (bucket pulling control command or bucket pushing control command) corresponding to the input operation signal to the bucket control mechanism 43 of the control valve 40, and the bucket control mechanism 43 operates according to the bucket control command. As a result, the bucket cylinder 13 and the bucket 6 perform operations according to the bucket operator operation amount.

[0062] Furthermore, since the same applies to turning and driving operations in normal control, detailed explanations of these operations will be omitted.

[0063] On the other hand, the machine control device 50 assists the operator in assist control. In other words, the machine control device 50 assists the operation of the work device 3 in assist control. In assist control, the machine control device 50 assists at least one of the operation of the boom 4, the arm 5, and the bucket 6.

[0064] The assist control may be, for example, a first assist control as shown below, a second assist control as shown below, or any other assist control.

[0065] The first assist control is a control in which the machine control device 50 assists the movement of the bucket 6, but does not assist the movement of the boom 4 or the arm 5. In other words, the first assist control includes bucket assist control for assisting the movement of the bucket 6. In this first assist control, the machine control device 50 controls the movement of the bucket 6 based on the bucket assist operation amount, while controlling the movement of the boom 4 based on the boom operator operation amount and controlling the movement of the arm 5 based on the arm operator operation amount.

[0066] When the machine control device 50 performs the first assist control during excavation work, the operator only needs to provide the operating device 30 with an arm-pulling operation to pull the arm 5 and a boom-raising operation to raise the boom 4, while not needing to provide the operating device 30 with a bucket-pulling operation to pull the bucket 6. In other words, during excavation work, the operator only needs to perform the arm-pulling operation and the boom-raising operation, and the machine control device 50 controls the movement of the bucket 6 based on the amount of bucket assist operation.

[0067] The second assist control is a control in which the machine control device 50 assists the movement of the bucket 6 and the boom 4, but does not assist the movement of the arm 5. That is, the second assist control includes bucket assist control for assisting the movement of the bucket 6 and boom assist control for assisting the movement of the boom 4. In this second assist control, the machine control device 50 controls the movement of the bucket 6 based on the bucket assist operation amount, controls the movement of the boom 4 based on the boom assist operation amount, and controls the movement of the arm 5 based on the arm operator operation amount. The bucket assist operation amount and the boom assist operation amount will be described later.

[0068] When the machine control device 50 performs second assist control during excavation work, the operator only needs to provide the operating device 30 with an arm-pulling operation to pull the arm 5, and does not need to provide the operating device 30 with a bucket-pulling operation to pull the bucket 6 or a boom-raising operation to raise the boom 4. In other words, during excavation work, the operator only needs to perform the arm-pulling operation to the operating device 30, and the machine control device 50 controls the movement of the bucket 6 based on the amount of bucket assist operation and controls the movement of the boom 4 based on the amount of boom assist operation.

[0069] [First Embodiment] First, a machine control device 50 and a construction machine 100 equipped therewith that embody the first embodiment of the machine control device 50 that perform the first assist control will be described. This first assist control includes bucket assist control for assisting the operation of the bucket 6 in excavation work.

[0070] In bucket assist control, the machine control device 50 determines the target bucket speed, which is a target value for the speed of the bucket 6, using arm movement information related to the movement of the arm 5. It then determines the bucket assist operation amount through feedback control based on the deviation between the target bucket speed and the speed of the bucket 6, and controls the movement of the bucket 6 based on the bucket assist operation amount.

[0071] In this embodiment, the speed of the bucket 6 can be brought closer to the target bucket speed while considering the movement of the arm 5; that is, the speed of the bucket 6 can be made to follow the target bucket speed while considering the movement of the arm 5. This makes it possible to operate the bucket 6 at a speed that allows for a balance between the movement of the arm 5 and the movement of the bucket 6 during excavation work, i.e., a speed suitable for excavation work. Therefore, the machine control device 50 enables the bucket 6 to hold a sufficient amount of soil during excavation work.

[0072] In this embodiment, the arm movement information includes at least one of information regarding the speed of the arm 5 and information regarding the posture of the arm 5. As shown in Figure 1, during excavation work, the bucket 6 needs to move backward along the ground, and this movement of the bucket 6 is achieved by an arm pulling motion in which the arm 5 rotates so that the tip 5b of the arm 5 approaches the upper rotating body 2. Therefore, the machine control device 50 determines the target bucket speed using at least one of information regarding the speed of the arm 5 (arm speed information) and information regarding the posture of the arm 5 (arm posture information). This makes it possible to balance the movement of the arm 5 and the movement of the bucket 6 during the excavation work, and makes it possible to operate the bucket 6 at a speed more suitable for the excavation work.

[0073] In Figure 1, for example, excavation by the bucket 6 begins when the bucket 6 is positioned at position P1. In this embodiment, the machine control device 50 determines the target speed of the bucket using information about the attitude of the arm 5 when excavation by the bucket 6 begins.

[0074] The position of the arm 5 when excavation by the bucket 6 is started is related to the distance (arm movement distance) that the tip 5b of the arm 5 approaches the upper slewing body 2 due to the arm pulling motion from the start to the completion of the excavation work. In other words, the position of the arm 5 when excavation by the bucket 6 is started is related to the distance (bucket movement distance) that the bucket 6 approaches the upper slewing body 2 underground due to the arm pulling motion from the start to the completion of the excavation work. In the excavation work, the bucket 6 moves in conjunction with the arm pulling motion and performs a bucket excavation operation (bucket pulling motion), which is an operation in which the bucket 6 rotates relative to the arm 5 so that the tip 6b of the bucket 6 approaches the upper slewing body 2. When the excavation work is completed and the bucket 6 is positioned, for example, at position P4 in Figure 1, it is preferable that the position of the bucket 6 is such that the opening of the bucket 6 faces upward, as is the case with the bucket 6 at position P4 (ideal position at the completion of excavation). The ideal position upon completion of excavation may be, for example, a position in which the periphery of the bucket 6 that defines the opening of the bucket 6 (the periphery located at the top of the bucket 6 at position P4 in Figure 1) is approximately horizontal.

[0075] Therefore, in this embodiment, the machine control device 50 determines the target bucket speed using information regarding the posture of the arm 5 when excavation by the bucket 6 is started. This makes it possible to have the bucket 6 perform the bucket excavation operation (the bucket pulling operation) at a speed suitable for the distance the arm moves from the start to the completion of the excavation work. Thus, in this embodiment, it is possible to balance the arm pulling operation and the bucket excavation operation regardless of the posture of the arm 5 when excavation by the bucket 6 is started, and it becomes possible to operate the bucket 6 at a speed more suitable for the excavation work.

[0076] The machine control device 50 may be configured to determine the target bucket speed using, for example, an arm start posture value, which is a value correlated with the posture of the arm 5 when excavation by the bucket 6 is started. The arm start posture value may be, for example, the angle θa1 of the arm 5 with respect to a predetermined reference when excavation by the bucket 6 is started, as shown in Figure 1. Specifically, for example, the angle θa1 of the arm 5 may be the angle of the arm 5 with respect to the horizontal plane (an example of the predetermined reference), the angle of the arm 5 with respect to the ground (an example of the predetermined reference) (arm-to-ground angle), or the angle of the arm 5 with respect to the boom 4 (an example of the predetermined reference). The arm start posture value may also be, for example, the length of the arm cylinder 12 when excavation by the bucket 6 is started. The angle θa2 of the arm 5 in the middle of the excavation work (position P2 in Figure 1) and the angle θa3 of the arm 5 in the final stages of the excavation work (position P3 in Figure 1) may, like angle θa1, be the angle of the arm 5 with respect to the predetermined reference.

[0077] In this embodiment, the machine control device 50 may also determine the target bucket speed using information regarding the attitude of the bucket 6 when excavation by the bucket 6 is started.

[0078] The position of the bucket 6 when excavation by the bucket 6 is started is related to the angle by which the bucket 6 needs to be rotated relative to the arm 5 to reach the ideal position at the completion of the excavation work (for example, the position of the bucket 6 at position P4 in Figure 1).

[0079] Therefore, in this embodiment, the machine control device 50 may determine the target bucket speed using information regarding the position of the bucket 6 when excavation by the bucket 6 is started. This makes it possible to make the bucket 6 perform the bucket excavation operation (the bucket pulling operation) at a speed suitable for the bucket 6 to rotate by the required rotation angle from the start to the completion of the excavation operation. Thus, in this embodiment, the bucket 6 can be operated at a speed more suitable for the excavation operation, regardless of the position of the bucket 6 when excavation by the bucket 6 is started.

[0080] The machine control device 50 may be configured to determine the target bucket speed using a bucket start posture value, which is a value correlated with the posture of the bucket 6 when excavation by the bucket 6 is started. The bucket start posture value may be, for example, the angle θb1 of the bucket 6 with respect to a predetermined reference when excavation by the bucket 6 is started, as shown in Figure 1. Specifically, for example, the angle θb1 of the bucket 6 may be the angle of the bucket 6 with respect to the horizontal plane (an example of the predetermined reference), or the angle of the bucket 6 with respect to the ground (an example of the predetermined reference) (bucket-to-ground angle). Also, the angle θb1 of the bucket 6 may be the angle of the bucket 6 with respect to the arm 5 (an example of the predetermined reference). Furthermore, the bucket start posture value may be, for example, the length of the bucket cylinder 13 when excavation by the bucket 6 is started. Note that the angle θb2 of the bucket 6 in the middle of the excavation work (position P2 in Figure 1) and the angle θb3 of the bucket 6 in the final stages of the excavation work (position P3 in Figure 1) may each be the angle of the bucket 6 with respect to the predetermined reference, similar to the angle θb1.

[0081] The arm movement information includes information regarding the speed of the arm 5, and it is preferable that the machine control device 50 is configured to set the bucket target speed to a predetermined first target value when the speed of the arm 5 is less than a predetermined arm speed threshold.

[0082] In this case, even if the arm 5 stops or its speed decreases, it is possible to avoid the bucket 6 stopping or its speed decreasing too much due to the decrease in the arm 5's speed, and to operate the bucket 6 at a speed close to the first target value. Specifically, when the load on the work device 3 becomes large during the excavation work, the arm 5 may stop or its speed may decrease significantly. Even in such cases, it is possible to reduce the load on the work device 3 by operating the bucket 6 at a speed close to the first target value without stopping the bucket 6. In this case, it becomes possible to eliminate the decrease in the arm 5's speed caused by the load. This makes it possible to avoid a significant decrease in the efficiency of the excavation work. The first target value is a value greater than zero.

[0083] Furthermore, in this embodiment, it is preferable that the machine control device 50 is configured to set the bucket target speed to a predetermined second target value when the position of the bucket 6 corresponds to the position at the end of the excavation work, such as when the bucket 6 is positioned at position P3 in Figure 1.

[0084] In this case, even if the speed of the bucket 6 is less than the second target value at the point when it is determined that the bucket 6's posture corresponds to the posture at the end of the excavation work, the speed of the bucket 6 will be increased to the second target value, making it easier for the bucket 6's posture to approach the ideal posture at the completion of the excavation work by the time the excavation work is completed. As a result, the bucket 6 will be able to hold more soil at the completion of the excavation work.

[0085] The machine control device 50 may be configured to set the bucket target speed to a predetermined second target value when the bucket posture value, which is a value correlated with the posture of the bucket 6, reaches a predetermined threshold value representing the end of the excavation work, which is a predetermined threshold value representing the end of the excavation work. The second target value is a value greater than zero. The second target value may be, for example, the maximum speed of the bucket 6 or a value close to the maximum speed.

[0086] Furthermore, in this embodiment, it is preferable that the machine control device 50 is configured to stop controlling the movement of the bucket 6 based on the bucket assist operation amount (bucket assist control) when the position of the bucket 6 corresponds to the ideal position at the completion of the excavation work (the ideal position at the completion of excavation).

[0087] The bucket 6 may reach the ideal position at the completion of the excavation work before the excavation work is completed. In such cases, if the bucket assist control is continued, the bucket 6 will rotate too much in the bucket pulling direction (bucket excavation direction), making it easier for the soil inside the bucket 6 to spill out. In this embodiment, even if the excavation work is not yet completed, if the position of the bucket 6 corresponds to the ideal position at the completion of the excavation work, the bucket assist control is stopped, thereby preventing the soil inside the bucket 6 from spilling out due to excessive rotation of the bucket 6.

[0088] The machine control device 50 may be configured to stop controlling the operation of the bucket 6 based on the bucket assist operation amount when the bucket posture value, which is a value correlated with the posture of the bucket 6, reaches a predetermined threshold value that indicates the completion of the excavation work.

[0089] Furthermore, in this embodiment, it is preferable that the machine control device 50 is configured to stop controlling the movement of the bucket 6 based on the bucket assist operation amount (bucket assist control) when the posture of the arm 5 corresponds to the ideal posture at the completion of the excavation work. For example, if the posture of the arm 5 corresponds to the ideal posture when the excavation work is not yet completed, the bucket assist control is stopped, thereby preventing the soil in the bucket 6 from spilling out due to excessive rotation of the arm 5 when the excavation work is completed.

[0090] The machine control device 50 may be configured to stop the bucket assist control when the arm posture value, which is a value correlated with the posture of the arm 5, reaches a predetermined threshold indicating the completion of the excavation work.

[0091] Furthermore, in this embodiment, it is preferable that the machine control device 50 (specifically, the high-level selection unit 54) is configured to control the operation of the bucket 6 based on the larger of the bucket assist operation amount and the bucket operator operation amount, which is a value corresponding to the bucket operation performed by the operator. If the operator wishes to operate the bucket 6 in response to the bucket operation performed by the operator, rather than operating the bucket 6 by the bucket assist control, the operator can simply provide the operating device 30 with an operation amount of a predetermined size or larger (for example, the maximum lever operation amount). As a result, the bucket 6 will operate in response to the bucket operation performed by the operator.

[0092] Furthermore, in this embodiment, it is preferable that the machine control device 50 is configured to stop controlling the operation of the bucket 6 based on the bucket assist operation amount (bucket assist control) when the pressure of at least one cylinder among the boom cylinder 11, arm cylinder 12, and bucket cylinder 13, which is predetermined to be used for pressure determination, is below a predetermined pressure threshold. For example, when the bucket 6 is in the air rather than underground, the pressure of the hydraulic cylinder is often low, and in this case, control of the operation of the bucket 6 based on the bucket assist operation amount is not necessary. Therefore, in this embodiment, when the pressure of at least one cylinder is below the predetermined pressure threshold, that is, when bucket assist control is not necessary, the machine control device 50 stops the bucket assist control. This makes it less likely for the bucket assist control to interfere with the operator's operation. For the above pressure determination, the pressure of any one of the three cylinders may be used, the pressure of any two of the three cylinders may be used, or the pressure of all three cylinders may be used.

[0093] Furthermore, in this embodiment, it is preferable that the machine control device 50 is configured to stop controlling the movement of the bucket 6 based on the bucket assist operation amount (bucket assist control) when the operating device 30 receives an operation other than an operation for excavation work. Since the bucket assist control is stopped when the operating device 30 receives an operation other than an operation for excavation work, the bucket assist control is less likely to interfere with the operator's operation when other operations are being performed.

[0094] Furthermore, in this embodiment, it is preferable that the machine control device 50 is configured to stop controlling the movement of the bucket 6 based on the bucket assist operation amount (bucket assist control) when the operating device 30 receives the aforementioned travel operation. Since the bucket assist control is stopped when the operating device 30 receives the aforementioned travel operation, the bucket assist control is less likely to interfere with the operator's operation when the construction machine 100 is in motion.

[0095] Figure 3 is a flowchart showing an example of the calculation process performed by the machine control device 50 during excavation work.

[0096] In step S11, the machine control device 50 determines whether or not an operation for excavation work has been performed. The machine control device 50 may determine whether or not an operation for excavation work has been performed based on the operation signal input from the operating device 30, for example. In normal excavation work, the operator mainly provides the operating device 30 with boom raising operation, arm pulling operation, and bucket pulling operation. On the other hand, when the machine control device 50 performs first assist control in excavation work, the operator provides the operating device 30 with arm pulling operation and boom raising operation, but does not need to provide the operating device 30 with bucket pulling operation. The machine control device 50 may determine that an operation other than an operation for excavation work has been performed if the operating device 30 receives an operation other than boom raising operation, arm pulling operation, and bucket pulling operation (for example, travel operation, arm pushing operation, boom raising operation, bucket pushing operation, etc.).

[0097] If an operation other than the operation for excavation work is performed (NO in step S11), the machine control device 50 stops controlling the movement of the bucket based on the bucket assist operation amount (the bucket assist control) and performs the normal control (step S26). In this case, the machine control device 50 may set the bucket assist operation amount to zero.

[0098] On the other hand, if an operation for excavation work is performed (YES in step S11), the machine control device 50 performs the process in step S12.

[0099] In step S12, the machine control device 50 determines whether the angle θb of the bucket 6 is less than a predetermined threshold, which is the excavation completion threshold TH1. The angle θb of the bucket 6 is an example of a bucket posture value, which is a value correlated with the posture of the bucket 6. The excavation completion threshold TH1 is a value that allows determination whether the posture of the bucket 6 corresponds to the ideal posture at the completion of the excavation work.

[0100] If the angle θb of the bucket 6 is greater than or equal to the drilling completion threshold TH1 (NO in step S12), that is, if the angle θb of the bucket 6 has reached the drilling completion threshold TH1, the machine control device 50 stops the bucket assist control and performs the normal control (step S26). In this case, the machine control device 50 may set the bucket assist operation amount to zero.

[0101] On the other hand, if the angle θb of the bucket 6 is less than the drilling completion threshold TH1 (YES in step S12), that is, if the angle θb of the bucket 6 has not reached the drilling completion threshold TH1, the machine control device 50 performs the process in step S13.

[0102] In step S13, the machine control device 50 determines whether the angle θa of the arm 5 is less than a predetermined threshold, which is the drilling completion threshold TH2. The angle θa of the arm 5 is an example of an arm posture value, which is a value correlated with the posture of the arm 5. The drilling completion threshold TH2 is a value that allows determination whether the posture of the arm 5 corresponds to the ideal posture at the completion of the drilling work.

[0103] If the angle θa of the arm 5 is greater than or equal to the excavation completion threshold TH2 (NO in step S13), that is, if the angle θa of the arm 5 has reached the excavation completion threshold TH2, the machine control device 50 stops the bucket assist control and performs the normal control (step S26). In this case, the machine control device 50 may set the bucket assist operation amount to zero.

[0104] On the other hand, if the angle θa of the arm 5 is less than the drilling completion threshold TH2 (YES in step S13), that is, if the angle θa of the arm 5 has not reached the drilling completion threshold TH2, the machine control device 50 performs the process in step S14.

[0105] Specifically, when the posture of arm 5 is the posture at the beginning of the excavation work (for example, the posture of arm 5 at position P1 in Figure 1), the angle θa1 of arm 5 is smaller than the excavation completion threshold TH2, and when the posture of arm 5 is the posture in the middle of the excavation work (for example, the posture of arm 5 at position P2 in Figure 1), the angle θa2 of arm 5 is smaller than the excavation completion threshold TH2.

[0106] Step S14 is a process for determining whether the bucket 6 is excavating or whether the bucket 6 is in the air. When the bucket 6 is in the air rather than underground, the pressure in the arm cylinder 12 is often low. Therefore, the machine control device 50 determines whether the bucket 6 is excavating or whether the bucket 6 is in the air by comparing the pressure in the arm cylinder 12 with a predetermined pressure threshold.

[0107] In step S14, the machine control device 50 determines whether the pressure in the arm cylinder 12 (for example, the pressure in the head side chamber of the arm cylinder 12) is equal to or greater than a predetermined pressure threshold TH3. If the pressure in the arm cylinder 12 is less than the pressure threshold TH3 (NO in step S14), the machine control device 50 stops the bucket assist control (bucket assist control: off) and performs the normal control (step S26). In this case, the machine control device 50 may set the bucket assist operation amount to zero.

[0108] On the other hand, if the pressure in the arm cylinder 12 is equal to or greater than the pressure threshold TH3 (YES in step S14), the machine control device 50 performs the process in step S15.

[0109] Furthermore, the machine control device 50 may switch the bucket assist control on and off based on conditions such as those shown in Figure 4. Figure 4 is a diagram showing an example of the conditions under which the machine control device 50 switches the bucket assist control on and off. In Figure 4, the "airborne determination flag" is the state of the bucket 6 stored by the machine control device 50, "Assist OFF" means to turn off the bucket assist control, that is, to stop the bucket assist control, and "Assist ON" means to turn on the bucket assist control, that is, to perform the bucket assist control. Also in Figure 4, the "previous output value" is the content of the flag in the flowchart of Figure 3 for the previous control cycle, and the "output value" is the content of the flag in the flowchart of Figure 3 for the current control cycle.

[0110] The conditions shown in Figure 4 take hysteresis into account. Specifically, the machine control device 50 switches the bucket assist control from off to on when the pressure P of the arm cylinder 12 is greater than threshold A, switches the bucket assist control from on to off when the pressure P is less than threshold B, and does not switch the bucket assist control on or off when the pressure P is within the range of threshold B and threshold A. Threshold A is a value greater than threshold B. By providing the above-described hysteresis in determining whether the bucket 6 is digging or in the air, the switching of the bucket assist control on and off becomes stable.

[0111] In step S15, the machine control device 50 determines whether the angle θb of the bucket 6 is less than a predetermined threshold, the final excavation threshold TH4. The final excavation threshold TH4 is a value that allows determination whether the position of the bucket 6 corresponds to the final position of the excavation work. The final excavation threshold TH4 is a value smaller than the excavation completion threshold TH1.

[0112] If the angle θb of the bucket 6 is greater than or equal to the final excavation threshold TH4 (NO in step S15), that is, if the angle θb of the bucket 6 has reached the final excavation threshold TH4, the machine control device 50 sets the target bucket speed to a predetermined constant VH (step S24). Then, the machine control device 50 performs the process in step S20.

[0113] On the other hand, if the angle θb of the bucket 6 is less than the final excavation threshold TH4 (YES in step S15), that is, if the angle θb of the bucket 6 has not reached the final excavation threshold TH4, the machine control device 50 performs the process in step S16.

[0114] Specifically, when the bucket 6 is in the initial position of the excavation work (for example, the position of the bucket 6 at position P1 in Figure 1), the angle θb1 of the bucket 6 is smaller than the final excavation threshold TH4, and when the bucket 6 is in the middle position of the excavation work (for example, the position of the bucket 6 at position P2 in Figure 1), the angle θb2 of the bucket 6 is smaller than the final excavation threshold TH4. The constant VH is an example of a second target value in this disclosure. The constant VH is a value greater than zero. The constant VH may be, for example, the maximum speed of the bucket 6 or a value close to the maximum speed, in which case the speed of the bucket 6 can be increased to the maximum speed or a value close to it.

[0115] In step S16, the machine control device 50 determines whether the speed of the arm 5 (for example, the angular velocity of the arm 5) is greater than or equal to a predetermined speed threshold TH5. The speed threshold TH5 is a value that allows determination of whether the arm 5 is stopped during the excavation work, or whether the speed of the arm 5 is low.

[0116] If the speed of arm 5 is less than the speed threshold TH5 (NO in step S16), that is, if arm 5 is stopped or the speed of arm 5 decreases, the machine control device 50 sets the target bucket speed to a predetermined constant VL (step S25). In this case, even if arm 5 stops or the speed of arm 5 decreases, it is possible to avoid the bucket 6 stopping or the speed of bucket 6 becoming too low due to the decrease in the speed of arm 5, and to operate bucket 6 at a speed close to the constant VL. The constant VL is a value greater than zero. The constant VL is a value less than the constant VH. The constant VL is an example of a first target value in this disclosure. Next, the machine control device 50 performs the process of step S20.

[0117] On the other hand, if the speed of arm 5 is greater than or equal to the speed threshold TH5 (YES in step S16), that is, if arm 5 is not stopped or the speed of arm 5 is not low, the machine control device 50 performs the process in step S17.

[0118] In step S17, the machine control device 50 (specifically, the target speed generation unit 51) calculates the gain α. The gain α is used when calculating the bucket target speed in step S19, which will be described later.

[0119] The machine control device 50 stores the arm start angle θa1, which is the angle θa of the arm 5 when excavation by the bucket 6 is started (when the excavation work is started). The machine control device 50 may, for example, store as the arm start angle θa1 the angle θa of the arm 5 at the time when the operator inputs to the input device (not shown) requesting the start of the excavation work. Alternatively, the machine control device 50 may, for example, store as the arm start angle θa1 the angle θa of the arm 5 at the time when the pressure of the arm cylinder 12 becomes above a predetermined pressure threshold (for example, above pressure threshold TH3). The arm start angle θa1 is an example of an arm start posture value, which is a value correlated with the posture of the arm 5 when excavation by the bucket 6 is started.

[0120] The machine control device 50 may store in advance a map representing the relationship between the gain α and the arm starting angle θa1. In this case, the machine control device 50 can calculate the gain α based on the arm starting angle θa1 and the map. The map may be a relational expression representing the relationship between the gain α and the arm starting angle θa1, or it may be a table representing the relationship between the gain α and the arm starting angle θa1.

[0121] The machine control device 50 may calculate the gain α using, for example, the following equation (1).

[0122] Gain α = (Excavation completion threshold TH2 - Arm start angle θa1) / (Excavation completion threshold TH2 - Arm angle θa at that point) ... (1)

[0123] In equation (1), "(excavation completion threshold TH2 - arm start angle θa1)" is the ideal rotation angle (ideal operating angle) of the arm 5 from the start to the completion of the excavation work, and "(excavation completion threshold TH2 - arm angle θa at that point)" is the ideal rotation angle of the arm 5 from that point until the completion of the excavation work. By calculating the target bucket speed using the gain α described above, the position of the bucket 6 becomes more likely to reach the ideal position at the completion of the excavation work at the time of completion of the excavation work.

[0124] In step S18, the machine control device 50 (specifically, the target speed generation unit 51) calculates the gain β. The gain β is used when calculating the bucket target speed in step S19, which will be described later.

[0125] The machine control device 50 stores the bucket start angle θb1, which is the angle θb of the bucket 6 when excavation by the bucket 6 is started (when the excavation work is started). The machine control device 50 may, for example, store the angle θb of the bucket 6 at the time when the operator inputs to the input device requesting the start of the excavation work as the bucket start angle θb1. Alternatively, the machine control device 50 may, for example, store the angle θb of the bucket 6 at the time when the pressure of the arm cylinder 12 becomes above a predetermined pressure threshold (for example, above pressure threshold TH3) as the bucket start angle θb1. The bucket start angle θb1 is an example of a bucket start posture value, which is a value correlated with the posture of the bucket 6 when excavation by the bucket 6 is started.

[0126] The machine control device 50 may store in advance a map representing the relationship between the gain β and the bucket starting angle θb1. In this case, the machine control device 50 can calculate the gain β based on the bucket starting angle θb1 and the map. The map may be a relational expression representing the relationship between the gain β and the bucket starting angle θb1, or it may be a table representing the relationship between the gain β and the bucket starting angle θb1.

[0127] The machine control device 50 may calculate the gain β using, for example, the following equation (2).

[0128] Gain β = (Excavation completion threshold TH1 - Bucket start angle θb1) / (Excavation completion threshold TH1 - Bucket angle θb at that point) ... (2)

[0129] In equation (2), "(excavation completion threshold TH1 - bucket starting angle θb1)" is the ideal rotation angle (ideal operating angle) of the bucket 6 from the start to the completion of the excavation work, and "(excavation completion threshold TH1 - bucket angle θb at that point)" is the ideal rotation angle of the bucket 6 from that point until the completion of the excavation work. By calculating the target bucket speed using the gain β described above, the position of the bucket 6 at the completion of the excavation work becomes more likely to reach the ideal position at the completion of the excavation work.

[0130] In step S19, the machine control device 50 (specifically, the target speed generation unit 51) calculates the target bucket speed, which is the target value of the speed of the bucket 6. The machine control device 50 may calculate the target bucket speed using, for example, the arm speed, a gain α, and a gain β. Specifically, the machine control device 50 may calculate the target bucket speed using, for example, the following equation (3).

[0131] Bucket target speed = Arm speed × α × β ... (3)

[0132] In equation (3), the bucket target speed may be the bucket target angular velocity, which is the target value of the angular velocity when the bucket 6 rotates around the bucket base end 6a. In equation (3), the arm speed is the speed of the arm 5 (the actual speed of the arm 5 at that time). The arm speed may also be the angular velocity of the arm 5, which is the angular velocity when the arm 5 rotates around the arm base end 5a. As shown in Figure 2, the machine control device 50 (specifically, the speed calculation unit 52) ​​can calculate the angular velocity of the arm 5 based on the operation information regarding the operation of the work device 3 acquired from the operation information detector 20.

[0133] Furthermore, in step S19, the machine control device 50 may calculate the target bucket speed using, for example, the arm speed, gain α, gain β, and angle ratio r. Specifically, the machine control device 50 may calculate the target bucket speed using, for example, the following equation (4). The target bucket speed obtained by equation (4) takes the angle ratio r into consideration, and therefore becomes a target value more suitable for the excavation work compared to the target bucket speed obtained by equation (3).

[0134] Bucket target velocity = Arm velocity × α × β × r ... (4)

[0135] The angle ratio r may be the ratio of the ideal rotation angle (ideal operating angle) of the arm 5 from the start to the completion of the excavation work to the ideal rotation angle (ideal operating angle) of the bucket 6 from the start to the completion of the excavation work. In this case, the machine control device 50 may calculate the angle ratio r using, for example, the following equation (5).

[0136] Angle ratio r = (Excavation completion threshold TH1 - Bucket start angle θb1) / (Excavation completion threshold TH2 - Arm start angle θa1) ... (5)

[0137] In equation (5), "(Excavation completion threshold TH2 - arm start angle θa1)" is the ideal rotation angle (ideal operating angle) of the arm 5 from the start to the completion of the excavation work, and "(Excavation completion threshold TH1 - bucket start angle θb1)" is the ideal rotation angle (ideal operating angle) of the bucket 6 from the start to the completion of the excavation work. By considering the angle ratio r described above in the calculation of the bucket target speed, the position of the bucket 6 at the completion of the excavation work becomes more likely to reach the ideal position at the completion of the excavation work.

[0138] In step S20, the machine control device 50 calculates the bucket speed deviation e(t), which is the difference between the target bucket speed and the bucket speed, using the following equation (6).

[0139] Bucket velocity deviation e(t) = Bucket target velocity - Bucket velocity ... (6)

[0140] In equation (6), the bucket speed is the speed of the bucket 6 (the actual speed of the bucket 6 at that time). The bucket speed may also be the angular velocity of the bucket 6, which is the angular velocity when the bucket 6 rotates around the bucket base end 6a. In this case, the bucket speed deviation e(t) is the deviation between the target angular velocity of the bucket and the angular velocity of the bucket 6.

[0141] In step S21, the machine control device 50 (specifically, the assist operation amount calculation unit 53) determines the bucket assist operation amount by feedback control based on the bucket speed deviation e(t). The machine control device 50 stores a calculation formula (for example, formula (7) below) that has been pre-designed for feedback control to bring the bucket speed deviation e(t) closer to zero. If the feedback control is PID control, the calculation formula includes proportional gain, integral gain, and differential gain that have been pre-determined based on methods such as experiments and simulations. The machine control device 50 can calculate the bucket assist operation amount by substituting the bucket speed deviation e(t) into formula (7).

[0142] Bucket assist maneuver amount = PID (bucket velocity deviation e(t)) ... (7)

[0143] In step S22, the machine control device 50 (specifically, the high-level selection unit 54) selects the larger of the bucket assist operation amount and the bucket operator operation amount (high-level selection). The bucket operator operation amount is a value corresponding to the bucket operation that the operating device 30 receives from the operator at that time, that is, the amount of the bucket operation such as the bucket pulling operation.

[0144] Then, in step S22, the machine control device 50 (specifically, the high-level selection unit 54) sets the selected value (operated amount) to the bucket operating amount. Specifically, if the bucket assist operating amount is greater than the bucket operator operating amount, the machine control device 50 sets the bucket assist operating amount to the bucket operating amount, and if the bucket operator operating amount is greater than the bucket assist operating amount, the machine control device 50 sets the bucket operator operating amount to the bucket operating amount. In this way, the machine control device 50 can control the operation of the bucket 6 based on the larger of the bucket assist operating amount and the bucket operator operating amount.

[0145] In step S23, the machine control device 50 converts the bucket operation amount set in step S22 into a control command (bucket pulling control command). This control command is a command value (for example, a current value) to be input to the bucket control mechanism 43. Specifically, the machine control device 50 inputs this control command to the electromagnetic directional control valve or the electromagnetic proportional valve. As a result, the bucket cylinder 13 and the bucket 6 perform operations according to the bucket operation amount. The machine control device 50 then repeats the process from step S11 onward.

[0146] [Second Embodiment] Next, a machine control device 50 and a construction machine 100 equipped therewith, according to the second embodiment which performs the second assist control, will be described.

[0147] As described above, this second assist control includes bucket assist control for assisting the movement of the bucket 6 during excavation work, and boom assist control for assisting the movement of the boom 4 during excavation work. That is, in this second assist control, the machine control device 50 controls the movement of the bucket 6 based on the bucket assist operation amount, controls the movement of the boom 4 based on the boom assist operation amount, and controls the movement of the arm 5 based on the arm operator operation amount. When the machine control device 50 performs the second assist control during excavation work, the operator does not need to give an arm pull operation to the operating device 30 to pull the arm 5, but does not need to give a bucket pull operation to the operating device 30 to pull the bucket 6 or a boom raise operation to raise the boom 4.

[0148] This second embodiment differs from the first embodiment in that the assist control further includes not only the bucket assist control but also the boom assist control, while other configurations of the second embodiment are the same as those of the first embodiment described above. For example, the bucket assist control in the second embodiment is the same as the bucket assist control in the first embodiment described with reference to Figures 1 to 4. Therefore, below, we will mainly describe the differences between the configuration of the second embodiment and the first embodiment, and omit the description of configurations of the second embodiment that are the same as those of the first embodiment.

[0149] Figure 5 is a block diagram showing an example of boom assist control performed by the machine control device 50 according to the second embodiment.

[0150] In the second embodiment, the machine control device 50 is configured to determine a boom assist operation amount to assist the operation of the boom 4 using movable part operation information, which is information relating to the operation of the movable part, and to control the operation of the boom 4 based on the boom assist operation amount. In the second embodiment, the movable part may be an arm 5, in which case the machine control device 50 determines the boom assist operation amount using arm operation information, which is information relating to the operation of the arm 5. In the second embodiment, the movable part may be an arm 5 and a bucket 6, in which case the machine control device 50 determines the boom assist operation amount using the arm operation information and bucket operation information, which is information relating to the operation of the bucket 6. The arm operation information and the bucket operation information are examples of information relating to the operation of the work device 3 (work device operation information). The following describes the case in which the machine control device 50 determines the boom assist operation amount using the arm operation information.

[0151] In the second embodiment, the target speed generation unit 51 uses the arm movement information to determine the boom target speed, which is the target value for the speed of the boom 4.

[0152] In the second embodiment, the speed calculation unit 52 calculates the speed of the boom 4, the speed of the arm 5, and the speed of the bucket 6 based on the operation information related to the operation of the work device 3 acquired from the operation information detector 20.

[0153] In the second embodiment, the assist operation amount calculation unit 53 calculates a boom speed deviation e(t), which is the difference between the boom target speed determined by the target speed generation unit 51 and the speed of the boom 4 (actual speed of the boom 4) calculated by the speed calculation unit 52, and determines the boom assist operation amount by feedback control based on the boom speed deviation e(t). In other words, the assist operation amount calculation unit 53 uses feedback control to determine a boom assist operation amount to assist the movement of the boom 4 so that the speed of the boom 4 follows the boom target speed. The machine control device 50 controls the movement of the boom 4 based on the boom assist operation amount.

[0154] In the second embodiment, the assist operation amount calculation unit 53 stores a calculation formula that has been pre-designed for feedback control to bring the boom speed deviation e(t) closer to zero. The feedback control may be PID control, PI control, PD control, or P control.

[0155] The high-position selection unit 54 not only controls the operation of the bucket 6 based on the larger of the bucket assist operation amount and the bucket operator operation amount, but also controls the operation of the boom 4 based on the larger of the boom assist operation amount and the boom operator operation amount, which is a value corresponding to the boom operation by the operator.

[0156] If the bucket assist control and boom assist control are not performed, the machine control device 50 performs the normal control, which controls the operation of the construction machine 100 in accordance with the operation of the operator operating the construction machine 100. In the second assist control, the machine control device 50 controls the operation of the bucket 6 based on the bucket assist operation amount, controls the operation of the boom 4 based on the boom assist operation amount, and controls the operation of the arm 5 based on the arm operator operation amount.

[0157] On the other hand, in the normal control described above, the machine control device 50 controls the movement of the boom 4 based on the boom operator operation amount, controls the movement of the arm 5 based on the arm operator operation amount, and controls the movement of the bucket 6 based on the bucket operator operation amount. The normal control in the second embodiment is the same as the normal control in the first embodiment.

[0158] In the second embodiment, when the machine control device 50 stops controlling the movement of the bucket based on the bucket assist operation amount (the bucket assist control), it also stops controlling the movement of the boom based on the boom assist operation amount (the boom assist control). This makes it less likely for the bucket assist control and the boom assist control to interfere with the operator's operation.

[0159] Figure 6 is a flowchart showing an example of the calculation process performed by the machine control device 50 according to the second embodiment. The flowchart in Figure 6 differs from the flowchart in Figure 3 in that it further includes step S30. Also, the processing content of steps S22, S23, and S26 in the flowchart in Figure 6 differs from the processing content of steps S22, S23, and S26 in the flowchart in Figure 3. Note that steps S11-S21, S24, and S25 in the flowchart in Figure 6 are the same as steps S11-S21, S24, and S25 in the flowchart in Figure 3, so the explanation of these steps S11-S21, S24, and S25 will be omitted.

[0160] In step S11 shown in Figure 6, the machine control device 50 determines whether or not an operation for excavation work has been performed, in the same manner as in step S11 shown in Figure 3. If an operation other than an operation for excavation work has been performed (NO in step S11), the machine control device 50 stops the control of the movement of the bucket 6 based on the bucket assist operation amount (the bucket assist control) and stops the control of the movement of the boom 4 based on the boom assist operation amount (the boom assist control) in step S26, and performs the normal control (step S26). In this case, the machine control device 50 may set the bucket assist operation amount to zero and the boom assist operation amount to zero. On the other hand, if an operation for excavation work has been performed (YES in step S11), the machine control device 50 performs the process in step S12. Note that an operation other than an operation for excavation work may be, for example, a travel operation, an arm pushing operation (the reverse operation of the arm pulling operation), or any other operation.

[0161] In step S12 shown in Figure 6, the machine control device 50 determines, in the same manner as in step S12 shown in Figure 3, whether the angle θb of the bucket 6 is less than a predetermined threshold, which is the drilling completion threshold TH1. If the angle θb of the bucket 6 is greater than or equal to the drilling completion threshold TH1 (NO in step S12), the machine control device 50 stops the bucket assist control and the boom assist control in step S26 and performs the normal control. In this case, the machine control device 50 may set the bucket assist operation amount to zero and the boom assist operation amount to zero. On the other hand, if the angle θb of the bucket 6 is less than the drilling completion threshold TH1 (YES in step S12), the machine control device 50 performs the process in step S13.

[0162] In step S13 shown in Figure 6, the machine control device 50 determines, in the same manner as in step S13 shown in Figure 3, whether the angle θa of the arm 5 is less than a predetermined threshold, which is the drilling completion threshold TH2. If the angle θa of the arm 5 is greater than or equal to the drilling completion threshold TH2 (NO in step S13), the machine control device 50 stops the bucket assist control and the boom assist control in step S26 and performs the normal control. In this case, the machine control device 50 may set the bucket assist operation amount to zero and the boom assist operation amount to zero. On the other hand, if the angle θa of the arm 5 is less than the drilling completion threshold TH2 (YES in step S13), the machine control device 50 performs the process in step S14.

[0163] In step S14 shown in Figure 6, the machine control device 50 determines whether the pressure of the arm cylinder 12 is equal to or greater than a predetermined threshold pressure threshold TH3, in the same manner as in step S14 shown in Figure 3. If the pressure of the arm cylinder 12 is less than the pressure threshold TH3 (NO in step S14), the machine control device 50 stops the bucket assist control and the boom assist control in step S26 and performs the normal control. In this case, the machine control device 50 may set the bucket assist operation amount to zero and the boom assist operation amount to zero. On the other hand, if the pressure of the arm cylinder 12 is equal to or greater than the pressure threshold TH3 (YES in step S14), the machine control device 50 performs the process in step S15.

[0164] Next, step S30 shown in Figure 6 will be described. The machine control device 50 according to the second embodiment may perform the process of step S30 after performing the process of step S21 shown in Figure 6. However, the timing of performing the process of step S30 is not limited to the specific example in Figure 6.

[0165] In step S21 shown in Figure 6, the machine control device 50 (specifically, the assist operation amount calculation unit 53) determines the bucket assist operation amount by feedback control based on the bucket speed deviation e(t), which is the difference between the bucket target speed and the bucket speed.

[0166] Next, in step S30 shown in Figure 6, the machine control device 50 (specifically, the assist operation amount calculation unit 53) determines the boom assist operation amount by feedback control based on the boom speed deviation e(t), which is the difference between the boom target speed and the boom speed. The machine control device 50 stores a calculation formula (for example, formula (8) below) that has been pre-designed for feedback control to bring the boom speed deviation e(t) closer to zero. If the feedback control is PID control, the calculation formula includes proportional gain, integral gain, and differential gain that have been predetermined based on methods such as experiments and simulations. The machine control device 50 can calculate the boom assist operation amount by substituting the boom speed deviation e(t) into formula (8).

[0167] Boom assist maneuver amount = PID (boom speed deviation e(t)) ... (8)

[0168] The machine control device 50 may calculate the boom target speed as follows, for example. The machine control device 50 may store in advance a map that represents the relationship between the boom target speed and the arm speed. In this case, the machine control device 50 can calculate the boom target speed based on the arm speed and the map. The map may be a relational expression that represents the relationship between the boom target speed and the arm speed, or it may be a table that represents the relationship between the boom target speed and the arm speed. The arm speed is the speed of the arm 5 (the actual speed of the arm 5 at that time), and the boom speed is the speed of the boom 4 (the actual speed of the boom 4 at that time).

[0169] Next, in step S22 shown in Figure 6, the machine control device 50 (specifically, the high-level selection unit 54) selects the larger of the bucket assist operation amount and the bucket operator operation amount, and selects the larger of the boom assist operation amount and the boom operator operation amount. The bucket operator operation amount is a value corresponding to the bucket operation received by the operator from the operating device 30 at that time, i.e., the amount of the bucket operation such as the bucket pulling operation. The boom operator operation amount is a value corresponding to the boom operation received by the operator from the operating device 30 at that time, i.e., the amount of the boom operation such as the boom raising operation.

[0170] Then, in step S22, the machine control device 50 (specifically, the high-level selection unit 54) sets the bucket operation amount to a value (operation amount) selected from the bucket assist operation amount and the bucket operator operation amount, and sets the boom operation amount to a value (operation amount) selected from the boom assist operation amount and the boom operator operation amount. Specifically, if the bucket assist operation amount is greater than the bucket operator operation amount, the machine control device 50 sets the bucket assist operation amount to the bucket operation amount, and if the bucket operator operation amount is greater than the bucket assist operation amount, the machine control device 50 sets the bucket operator operation amount to the bucket operation amount. Also, if the boom assist operation amount is greater than the boom operator operation amount, the machine control device 50 sets the boom assist operation amount to the boom operation amount, and if the boom operator operation amount is greater than the boom assist operation amount, the machine control device 50 sets the boom operator operation amount to the boom operation amount. As a result, the machine control device 50 can control the movement of the bucket 6 based on the larger of the bucket assist operation amount and the bucket operator operation amount, and can control the movement of the boom 4 based on the larger of the boom assist operation amount and the boom operator operation amount.

[0171] In step S23 shown in Figure 6, the machine control device 50 converts the bucket manipulation amount set in step S22 into a control command (bucket pulling control command). This control command is a command value (for example, a current value) to be input to the bucket control mechanism 43. Specifically, the machine control device 50 inputs this control command to the electromagnetic directional control valve or the electromagnetic proportional valve. As a result, the bucket cylinder 13 and the bucket 6 perform operations according to the bucket manipulation amount.

[0172] Similarly, in step S23 shown in Figure 6, the machine control device 50 converts the boom operation amount set in step S22 into a control command (boom raising control command). This control command is a command value (for example, a current value) to be input to the boom control mechanism 41. Specifically, the machine control device 50 inputs this control command to the electromagnetic directional control valve or the electromagnetic proportional valve. As a result, the boom cylinder 11 and the boom 4 perform operations according to the boom operation amount.

[0173] The machine control device 50 then repeats the process from step S11 onwards in Figure 6.

[0174] [Modified Version of the Second Embodiment] Next, a machine control device 50 and a construction machine 100 equipped therewith, according to a modified version of the second embodiment that performs a second assist control, will be described. The second assist control according to this modified version includes, similar to the second embodiment described above, bucket assist control for assisting the movement of the bucket 6 in excavation work and boom assist control for assisting the movement of the boom 4 in excavation work.

[0175] In this modified second assist control, the machine control device 50 controls the movement of the bucket 6 based on the bucket assist operation amount, the movement of the boom 4 based on the boom assist operation amount, and the movement of the arm 5 based on the arm operator operation amount. The bucket assist control in this modified example is the same as the bucket assist control in the first embodiment described with reference to Figures 1 to 4. In this modified example, the arm 5 also moves according to the arm operator operation amount, similar to the first embodiment. Therefore, the following description of the modified example will mainly focus on the boom assist control.

[0176] In the boom assist control according to this modified example, the machine control device 50 uses information regarding the speed of the combined center of gravity of the work device 3 (combined center of gravity speed information) to determine the amount of boom assist operation to assist the movement of the boom 4, and controls the movement of the boom 4 based on the amount of boom assist operation. This modified example differs from the second embodiment in that it determines the amount of boom assist operation using the combined center of gravity speed information. The combined center of gravity speed information is an example of information regarding the operation of the work device 3 (work device operation information).

[0177] In this modified example, in the block diagram shown in Figure 5, the target velocity generation unit 51 determines the target velocity of the composite center of gravity (composite center of gravity target velocity), and the velocity calculation unit 52 calculates the velocity of the composite center of gravity (actual velocity of the composite center of gravity). The assist operation amount calculation unit 53 calculates the composite center of gravity velocity deviation e(t), which is the difference between the composite center of gravity target velocity and the velocity of the composite center of gravity, and determines the boom assist operation amount by feedback control based on the composite center of gravity velocity deviation e(t). In other words, the assist operation amount calculation unit 53 uses feedback control to determine the boom assist operation amount to assist the operation of the boom 4 so that the velocity of the composite center of gravity follows the composite center of gravity target velocity. The machine control device 50 controls the operation of the boom 4 based on the boom assist operation amount. As a result, the boom 4 operates so that the velocity of the composite center of gravity follows the composite center of gravity target velocity.

[0178] The machine control device 50 may set a target speed suitable for excavation work, which is stored in the database, as the composite center of gravity target speed. The target speed suitable for excavation work may be, for example, a value included in the past work data of a skilled operator. Furthermore, if the operator makes an input to a predetermined input device to set the composite center of gravity target speed, the machine control device 50 may set the composite center of gravity target speed based on that input.

[0179] During the excavation work, the boom 4 performs a boom-raising operation. If the load on the work device 3 increases during this excavation work and the speed of the composite center of gravity becomes less than the target speed of the composite center of gravity, the boom-raising speed of the boom 4 increases, and the bucket 6 moves upward as a result, reducing the load. This reduces the composite center of gravity velocity deviation e(t). In other words, in this modified example, the operation of the boom 4 is controlled using the composite center of gravity, thereby reducing the load during the excavation work.

[0180] The combined center of gravity of the working device 3 is the combined value of the center of gravity of the boom 4, the center of gravity of the arm 5, and the center of gravity of the bucket 6. The combined center of gravity may be expressed, for example, in coordinates in a coordinate system. The boom 4, arm 5, and bucket 6 operate substantially along a vertical plane. Therefore, the coordinate system may be a two-dimensional coordinate system (xy coordinate system) consisting of x and y axes parallel to the vertical plane. The origin of this coordinate system is not particularly limited, but may be, for example, the base end 4a of the boom 4.

[0181] The position of the combined center of gravity (Xg, Yg) may be calculated using the position of the center of gravity of the boom 4 (x1, y1), the position of the center of gravity of the arm 5 (x2, y2), the position of the center of gravity of the bucket 33 (x3, y3), and the following equation (9).

[0182]

[0183] In equation (9), m1, m2, and m3 are the mass of the boom 4, the mass of the arm 5, and the mass of the bucket 6, respectively. The machine control device 50 may store the masses m1, m2, and m3 in advance. The mass m3 of the bucket 6 may or may not include the mass of the soil in the bucket 6. The mass of the soil in the bucket 6 may be measured by a sensor not shown in the figure, calculated from the pressure of the boom cylinder 11, or measured or calculated by other known methods.

[0184] The speed calculation unit 52 may pre-store information about the location of the center of gravity of the boom 4 (boom center of gravity information), information about the location of the center of gravity of the arm 5 (arm center of gravity information), and information about the location of the center of gravity of the bucket 6 (bucket center of gravity information). In this case, the speed calculation unit 52 can calculate the position of the center of gravity of the boom 4 (x1, y1) based on the detection result input from the motion information detector 20 and the boom center of gravity information. The speed calculation unit 52 can calculate the position of the center of gravity of the arm 5 (x2, y2) based on the detection result input from the motion information detector 20 and the arm center of gravity information, and can calculate the position of the center of gravity of the bucket 6 (x3, y3) based on the detection result input from the motion information detector 20 and the bucket center of gravity information.

[0185] Since the velocity of the composite center of gravity is the amount of change per unit time of the position (Xg, Yg) of the composite center of gravity, the velocity calculation unit 52 can calculate the velocity of the composite center of gravity using the position (Xg, Yg) of the composite center of gravity, which is calculated sequentially.

[0186] In this modified example, the machine control device 50 stores a pre-designed calculation formula (for example, formula (10) below) for feedback control that brings the combined center of gravity velocity deviation e(t) closer to zero. When the feedback control is PID control, the machine control device 50 can calculate the boom assist operation amount by substituting the combined center of gravity velocity deviation e(t) into formula (10) below.

[0187] Boom assist amount = PID (composite center of gravity velocity deviation e(t)) ... (10)

[0188] [Other Modifications] The embodiments and modifications of the present disclosure have been described above, but the present disclosure is not limited to the embodiments described above and further includes, for example, the following modifications.

[0189] (A) Regarding the construction machinery system, in the above embodiment the construction machine 100 is equipped with a machine control device 50, but the machine control device 50 does not have to be equipped in the construction machine 100, it may constitute a separate device from the construction machine 100, or it may be equipped in a separate device from the construction machine 100.

[0190] Figure 7 shows an example of a construction machinery control system equipped with a machine control device 50. This construction machinery system may also include a construction machine 100 and a remote control device 200. In this case, the remote control device 200 may also include the machine control device 50. The construction machine 100 and the machine control device 50 of the remote control device 200 are communicated together via a network 500 such as the Internet, a telephone network, or a mobile phone network.

[0191] The construction machinery system may include a construction machine 100 and a portable information terminal 300. In this case, the portable information terminal 300 may include a machine control device 50. The construction machine 100 and the machine control device 50 of the portable information terminal 300 are communicated together via a network 500. The portable information terminal 300 may be, for example, an information terminal such as a tablet computer, smartphone, laptop personal computer, or desktop personal computer.

[0192] The construction machinery system may include a construction machine 100 and a management device 400 such as a server. In this case, the management device 400 may include a machine control device 50. The construction machine 100 and the machine control device 50 of the management device 400 are communicated to each other via a network 500. The management device 400 may be, for example, an information terminal in a cloud service provided as a service over a network such as the Internet.

[0193] Furthermore, in a construction machinery system, the construction machine 100 may provide some of the functions of the machine control device 50, while at least one of the remote control device 200, the portable information terminal 300, and the management device 400 may provide other parts of the functions of the machine control device 50.

[0194] (B) Regarding the movable part, in the above embodiment the movable part is the arm 5, but the movable part in this disclosure may be, for example, a boom.

[0195] (C) Regarding the program, a modified program of the above embodiment causes a computer (e.g., a machine control device 50) that controls the operation of a construction machine 100 comprising a lower traveling body 1, an upper rotating body 2 rotatably supported on the lower traveling body 1, and a working device 3 including a movable part and a bucket 6 rotatably supported on the upper rotating body 2, to perform the following steps: determine a target bucket speed, which is a target value for the speed of the bucket 6, using movable part operation information, which is information regarding the operation of the movable part; determine a bucket assist operation amount by feedback control based on the deviation between the target bucket speed and the speed of the bucket 6; and control the operation of the bucket 6 based on the bucket assist operation amount.

[0196] The program may be provided, for example, in the form of a cloud service delivered via a network from one or more terminals. Alternatively, the program may be provided, for example, in the form of non-temporarily recorded on a computer-readable recording medium. In this case, the computer reads the program from the recording medium, records it to an internal or external recording device, and executes it. Alternatively, the program may be pre-recorded on a non-temporarily recorded recording medium such as a magnetic disk, optical disk, or magneto-optical disk, and provided from that recording medium to another terminal via a communication line.

[0197] (D) Assist control In the first embodiment in which the first assist control is performed, during excavation work, the operator only needs to perform arm pulling operations and boom raising operations, and the machine control device 50 controls the movement of the bucket 6 based on the bucket assist operation amount. In the second embodiment in which the second assist control is performed, during excavation work, the operator only needs to perform arm pulling operations on the operating device 30, and the machine control device 50 controls the movement of the bucket 6 based on the bucket assist operation amount and controls the movement of the boom 4 based on the boom assist operation amount. However, the assist control is not limited to these specific examples.

[0198] In excavation work, for example, the operator may perform not only arm pulling operations but also bucket excavation operations on the operating device 30, and the machine control device 50 may determine the target bucket speed using movable part operation information (e.g., arm operation information), determine the bucket assist operation amount by feedback control based on the deviation between the target bucket speed and the speed of the bucket 6, and control the operation of the bucket 6 based on the bucket assist operation amount. In this case, the bucket assist operation amount may be a value obtained by correcting the bucket operator operation amount so that the speed of the bucket 6 follows the target bucket speed.

[0199] (E) Regarding the leveling work, in the above embodiment the work performed by the work device 3 is excavation work, but it may also be leveling work. In this case, the machine control device 50 may be configured to determine the target bucket speed, which is a target value for the speed of the bucket 6, using movable part operation information, which is information regarding the operation of the movable part (for example, the arm 5), to determine the bucket assist operation amount by feedback control based on the deviation between the target bucket speed and the speed of the bucket 6, and to control the operation of the bucket 6 based on the bucket assist operation amount. The leveling work is work to level the ground, slope, or other construction target at a predetermined angle (target construction angle), and, similar to the excavation work, it is work that requires balancing the operation of the arm 5 and the operation of the bucket 6.

[0200] (F) In the flowchart, in either or both of Figure 3 and Figure 6, at least one of the decision processes in steps S11, S12, S13, S14, S15, and S16 may be omitted. Also, in either or both of Figure 3 and Figure 6, the higher selection process in step S22 may be omitted.

[0201] (G) The machine control device 50 may calculate the bucket target speed using, for example, the following equation (11).

[0202] Bucket target velocity = Arm velocity × r ... (11)

[0203] In equation (11), the arm speed is the speed of arm 5 (the actual speed of arm 5 at that time), and "r" is the angle ratio. The right-hand side of equation (11) may include terms that add constants or terms that multiply constants.

[0204] As described above, this disclosure provides a machine control device, a construction machine, a construction machine control system, a method for controlling a construction machine, and a program that enable the bucket of the construction machine to be operated at a speed suitable for operations such as excavation and leveling.

[0205] A machine control device according to the first embodiment is a machine control device for controlling the operation of a construction machine comprising a lower traveling body, an upper rotating body rotatably supported on the lower traveling body, and a working device including a movable part and a bucket rotatably supported on the upper rotating body, wherein the machine control device determines a target bucket speed, which is a target value for the speed of the bucket, using movable part operation information, which is information relating to the operation of the movable part, determines a bucket assist operation amount by feedback control based on the deviation between the bucket target speed and the speed of the bucket, and controls the operation of the bucket based on the bucket assist operation amount.

[0206] The machine control device according to this first embodiment determines the bucket assist operation amount by feedback control based on the deviation between the bucket target speed determined using the movable part operation information and the bucket speed, and controls the operation of the bucket based on this bucket assist operation amount. This makes it possible to bring the bucket speed closer to the bucket target speed while considering the operation of the movable part, that is, to make the bucket speed follow the bucket target speed while considering the operation of the movable part. As a result, it becomes possible to operate the bucket at a speed that allows for a balance between the operation of the movable part and the operation of the bucket in operations such as excavation and leveling, that is, at a speed suitable for operations such as excavation and leveling. Therefore, the machine control device according to the first embodiment makes it possible for the bucket to hold a sufficient amount of soil in operations such as excavation and leveling.

[0207] A machine control device according to a second embodiment may further include the following configuration in addition to that of a machine control device according to a first embodiment. That is, in a machine control device according to a second embodiment, the movable part is preferably an arm, and the movable part operation information preferably includes at least one of information relating to the speed of the arm and information relating to the posture of the arm. In this second embodiment, it becomes possible to balance the operation of the arm and the operation of the bucket in operations such as excavation and leveling, and it becomes possible to operate the bucket at a speed more suitable for operations such as excavation and leveling.

[0208] A machine control device according to a third embodiment may further include the following configuration in a machine control device according to a first or second embodiment. That is, in the third embodiment, the movable part is an arm, and it is preferable that the machine control device is configured to determine the target speed of the bucket using information about the posture of the arm when work by the bucket is started (for example, when excavation is started or leveling is started). In this third embodiment, regardless of the posture of the arm when the work by the bucket is started, it becomes possible to balance the movement of the arm and the movement of the bucket (for example, in the case of excavation work, the balance between the arm pulling movement and the bucket excavation movement), and it becomes possible to operate the bucket at a speed more suitable for work such as excavation work and leveling work.

[0209] A machine control device according to the fourth embodiment is preferably further configured in addition to the machine control device according to any one of the first to third embodiments. That is, a machine control device according to the fourth embodiment is preferably configured to determine the target speed of the bucket using information about the attitude of the bucket when work by the bucket is started (for example, when excavation is started or when leveling is started). In this fourth embodiment, the bucket can be operated at a speed more suitable for the work, such as the excavation work or the leveling work, regardless of the attitude of the bucket when the work by the bucket is started.

[0210] A machine control device according to the fifth embodiment preferably further comprises the following configuration in a machine control device according to any one of the first to fourth embodiments. That is, in the fifth embodiment, the movable part is an arm, the movable part operation information includes information regarding the speed of the arm, and the machine control device is preferably configured to set the bucket target speed to a predetermined first target value when the speed of the arm is less than a predetermined arm speed threshold. In this fifth embodiment, even if the arm stops or the speed of the arm decreases, it is possible to avoid the bucket stopping or the speed of the bucket becoming too low due to the decrease in the speed of the arm, and to operate the bucket at a speed close to the first target value.

[0211] The machine control device according to the sixth embodiment preferably further comprises the following configuration in addition to the machine control device according to any one of the first to fifth embodiments. That is, the machine control device according to the sixth embodiment preferably is configured to set the bucket target speed to a predetermined second target value when the posture of the bucket corresponds to the posture at the end of the excavation work. In this sixth embodiment, the bucket target speed is set to the second target value when the posture of the bucket corresponds to the posture at the end of the excavation work. Therefore, even if the speed of the bucket is less than the second target value at the time it is determined that the posture of the bucket corresponds to the posture at the end of the excavation work, the speed of the bucket is increased to the second target value, so that the posture of the bucket approaches the ideal posture at the completion of the excavation work (ideal posture at the completion of excavation) by the time the excavation work is completed. As a result, the bucket is more likely to hold more soil when the excavation work is completed.

[0212] The machine control device according to the seventh embodiment preferably further comprises the following configuration in addition to the machine control device according to any one of the first to sixth embodiments. That is, the machine control device according to the seventh embodiment preferably is configured to stop controlling the movement of the bucket based on the bucket assist operation amount (bucket assist control) when the position of the bucket corresponds to the ideal position at the completion of the excavation work (the ideal position at the completion of excavation). In this seventh embodiment, it is possible to suppress the spillage of soil from the bucket due to excessive rotation of the bucket during the excavation work.

[0213] The machine control device according to the eighth embodiment may further include the following configuration in the machine control device according to any one of the first to seventh embodiments. That is, in the eighth embodiment, the movable part is an arm, and it is preferable that the machine control device is configured to stop controlling the movement of the bucket based on the bucket assist operation amount (bucket assist control) when the posture of the arm corresponds to the ideal posture at the completion of the excavation work. In this eighth embodiment, it is possible to suppress the spillage of soil from the bucket due to excessive rotation of the arm at the time the excavation work is completed.

[0214] A machine control device according to the ninth embodiment preferably further comprises the following configuration in addition to a machine control device according to any one of the first to eighth embodiments. That is, in a machine control device according to the ninth embodiment, the construction machine is provided with an operating device that receives bucket operations by an operator for instructing the operation of the bucket, and the machine control device is preferably configured to control the operation of the bucket based on the larger of the bucket assist operation amount and the operator operation amount, which is a value corresponding to the bucket operation by the operator. In this ninth embodiment, if the operator wishes to operate the bucket in response to the bucket operation by the operator rather than operating the bucket by the bucket assist control, the operator only needs to provide the operating device with a bucket operation amount of a predetermined size or larger. As a result, the bucket operates in response to the bucket operation by the operator.

[0215] The machine control device according to the tenth embodiment preferably further comprises the following configuration in addition to the machine control device according to any one of the first to ninth embodiments. That is, in the machine control device according to the tenth embodiment, the construction machine is provided with a plurality of hydraulic cylinders for moving the work device, and the machine control device is preferably configured to stop controlling the operation of the bucket based on the bucket assist operation amount (bucket assist control) when the pressure of at least one of the plurality of hydraulic cylinders is below a predetermined pressure threshold. In this tenth embodiment, when the pressure of at least one of the plurality of hydraulic cylinders is below the predetermined pressure threshold, that is, when the bucket assist control is not needed, the machine control device stops the bucket assist control. This makes it less likely for the bucket assist control to interfere with the operator's operation.

[0216] The machine control device according to the 11th embodiment preferably further comprises the following configuration in addition to the machine control device according to any one of the first to tenth embodiments. That is, in the machine control device according to the 11th embodiment, the construction machine is provided with an operating device that receives operations from an operator to instruct the operation of the work device, and the machine control device is preferably configured to stop the control of the bucket operation based on the bucket assist operation amount (bucket assist control) when the operating device receives an operation other than an operation for excavation work. In this 11th embodiment, since the bucket assist control is stopped when the operating device receives an operation other than an operation for excavation work, the bucket assist control is less likely to interfere with the operator's operation when work other than excavation work is being performed. If the work performed by the work device is leveling work, the machine control device may be configured to stop the bucket assist control when the operating device receives an operation other than an operation for leveling work.

[0217] The machine control device according to the twelfth embodiment preferably further comprises the following configuration in addition to the machine control device according to any one of the first to eleventh embodiments. That is, in the machine control device according to the twelfth embodiment, the construction machine is provided with an operating device that receives a driving operation by an operator to instruct the driving movement of the lower traveling body, and the machine control device is preferably configured to stop the control of the movement of the bucket based on the bucket assist operation amount (bucket assist control) when the operating device receives the driving operation. In this twelfth embodiment, since the bucket assist control is stopped when the operating device receives the driving operation, the bucket assist control is less likely to interfere with the operator's operation when the construction machine is traveling.

[0218] The machine control device according to the 13th embodiment preferably further comprises the following configuration in addition to the machine control device according to any one of the first to 12 embodiments. That is, in the machine control device according to the 13th embodiment, the working device includes a boom rotatably supported by the upper slewing body, an arm rotatably supported by the boom, and a bucket rotatably supported by the arm, the machine control device is configured to determine a boom assist operation amount to assist the operation of the boom using information regarding the operation of the working device (working device operation information), and to control the operation of the boom based on the boom assist operation amount, and the machine control device is preferably configured to stop the control of the operation of the boom based on the boom assist operation amount (boost assist control) when the control of the operation of the bucket based on the bucket assist operation amount (bucket assist control) is stopped. In this 13th embodiment, when the bucket assist control is stopped, the boom assist control is also stopped, so that in such a situation the bucket assist control and the boom assist control are less likely to interfere with the operator's operation. The aforementioned work device operation information may be the movable part operation information, the combined center of gravity velocity information, or other information.

[0219] The construction machine according to the 14th embodiment comprises a machine control device according to any one of the 1st to 13th embodiments, the lower traveling body, the upper rotating body, and the working device.

[0220] A construction machinery control system according to the 15th embodiment comprises a machine control device according to any one of the first to 13 embodiments, and the construction machinery.

[0221] A control method for a construction machine according to the 16th embodiment is a control method for a construction machine for controlling the operation of a construction machine comprising a lower traveling body, an upper rotating body rotatably supported on the lower traveling body, and a working device including a movable part and a bucket rotatably supported on the upper rotating body, the method comprising: determining a target bucket speed, which is a target value of the bucket's speed, using movable part operation information, which is information relating to the operation of the movable part; determining a bucket assist operation amount by feedback control based on the deviation between the bucket target speed and the bucket's speed; and controlling the operation of the bucket based on the bucket assist operation amount.

[0222] A program according to the 17th embodiment causes a computer that controls the operation of a construction machine comprising a lower traveling body, an upper rotating body rotatably supported on the lower traveling body, and a working device including a movable part and a bucket rotatably supported on the upper rotating body, to perform the steps of: determining a target bucket speed, which is a target value for the speed of the bucket, using movable part operation information, which is information relating to the operation of the movable part; determining a bucket assist operation amount by feedback control based on the deviation between the target bucket speed and the speed of the bucket; and controlling the operation of the bucket based on the bucket assist operation amount.

Claims

1. A machine control device for controlling the operation of a construction machine comprising a lower traveling body, an upper rotating body rotatably supported on the lower traveling body, and a working device including a movable part and a bucket rotatably supported on the upper rotating body, wherein the machine control device is configured to determine a target bucket speed, which is a target value of the bucket's speed, using movable part operation information, which is information relating to the operation of the movable part, to determine a bucket assist operation amount by feedback control based on the deviation between the bucket target speed and the bucket's speed, and to control the operation of the bucket based on the bucket assist operation amount.

2. A machine control device according to claim 1, wherein the movable part is an arm, and the movable part operation information includes at least one of information relating to the speed of the arm and information relating to the posture of the arm.

3. A machine control device according to claim 1 or 2, wherein the movable part is an arm, and the machine control device is configured to determine the target speed of the bucket using information relating to the posture of the arm when work by the bucket is started.

4. A machine control device according to any one of claims 1 to 3, wherein the machine control device is configured to determine the target speed of the bucket using information relating to the attitude of the bucket when work by the bucket is started.

5. A machine control device according to any one of claims 1 to 4, wherein the movable part is an arm, the movable part operation information includes information relating to the speed of the arm, and the machine control device is configured to set the bucket target speed to a predetermined first target value when the speed of the arm is less than a predetermined arm speed threshold.

6. A machine control device according to any one of claims 1 to 5, wherein the machine control device is configured to set the bucket target speed to a predetermined second target value when the position of the bucket corresponds to the position at the end of the excavation work.

7. A machine control device according to any one of claims 1 to 6, wherein the machine control device is configured to stop controlling the operation of the bucket based on the bucket assist amount when the position of the bucket corresponds to the ideal position at the completion of the excavation work.

8. A machine control device according to any one of claims 1 to 7, wherein the movable part is an arm, and the machine control device is configured to stop controlling the movement of the bucket based on the bucket assist amount when the posture of the arm corresponds to the ideal posture at the completion of the excavation work.

9. A machine control device according to any one of claims 1 to 8, wherein the construction machine includes an operating device for receiving bucket operations by an operator for instructing the operation of the bucket, and the machine control device is configured to control the operation of the bucket based on the larger of the bucket assist operation amount and the operator operation amount which is a value corresponding to the bucket operation by the operator.

10. A machine control device according to any one of claims 1 to 9, wherein the construction machine comprises a plurality of hydraulic cylinders for operating the work device, and the machine control device is configured to stop controlling the operation of the bucket based on the bucket assist amount when the pressure of at least one of the plurality of hydraulic cylinders is less than a predetermined pressure threshold.

11. A machine control device according to any one of claims 1 to 10, wherein the construction machine includes an operating device that receives operations from an operator for instructing the operation of the work device, and the machine control device is configured to stop controlling the operation of the bucket based on the bucket assist operation amount when the operating device receives an operation other than an operation for excavation work.

12. A machine control device according to any one of claims 1 to 11, wherein the construction machine is equipped with an operating device that receives a travel operation by an operator for instructing the travel operation of the lower traveling body, and the machine control device is configured to stop controlling the operation of the bucket based on the bucket assist operation amount when the operating device receives the travel operation.

13. A machine control device according to any one of claims 1 to 12, wherein the working device includes a boom rotatably supported on the upper slewing body, an arm rotatably supported on the boom, and a bucket rotatably supported on the arm, wherein the machine control device is configured to determine a boom assist operation amount for assisting the movement of the boom using information relating to the operation of the working device, and to control the movement of the boom based on the boom assist operation amount, and the machine control device is configured to stop controlling the movement of the boom based on the boom assist operation amount when stopping the control of the movement of the bucket based on the bucket assist operation amount.

14. A construction machine comprising: a machine control device according to any one of claims 1 to 13; the lower traveling body; the upper rotating body; and the working device.

15. A construction machine control system comprising a machine control device according to any one of claims 1 to 13, and the construction machine.

16. A method for controlling the operation of a construction machine comprising a lower traveling body, an upper rotating body rotatably supported on the lower traveling body, and a working device including a movable part and a bucket rotatably supported on the upper rotating body, the method comprising: determining a target bucket speed, which is a target value for the speed of the bucket, using movable part operation information, which is information relating to the operation of the movable part; determining a bucket assist operation amount by feedback control based on the deviation between the bucket target speed and the speed of the bucket; and controlling the operation of the bucket based on the bucket assist operation amount.

17. A program for a computer that controls the operation of a construction machine comprising a lower traveling body, an upper rotating body rotatably supported on the lower traveling body, and a working device including a movable part and a bucket rotatably supported on the upper rotating body, to perform the following steps: determining a target bucket speed, which is a target value for the speed of the bucket, using movable part operation information, which is information relating to the operation of the movable part; determining a bucket assist operation amount by feedback control based on the deviation between the target bucket speed and the speed of the bucket; and controlling the operation of the bucket based on the bucket assist operation amount.

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