Construction machine

Abstract

The present application provides a construction machine capable of suppressing an increase in digging resistance in a digging operation and suppressing a decrease in efficiency of the digging operation. A controller (50) of the construction machine (10) determines a contained state of sandy soil contained in a bucket (6), and outputs a resistance reduction command signal that is a command signal for causing a work implement (3) to act in such a manner that the bucket (6) is displaced in a resistance reduction direction (D2, D3, D4) that is a direction in which digging resistance acting on the bucket (6) can be reduced, in accordance with a determination result of the contained state.

Description

Technical Field

[0001] This invention relates to engineering machinery such as hydraulic excavators. Background Technology

[0002] Patent document 1 discloses a hydraulic excavator in which, when the bucket is moving forward in the ground to excavate the ground, that is, during excavation, the magnitude of the digging reaction force borne by the bucket from the ground is measured, and the swing position of the boom is changed according to the measured magnitude of the digging reaction force. If the measured digging force is large, the boom causes the forward direction of the bucket to be deflected upward.

[0003] Patent document 2 discloses a work machine control device for a power excavator. This work machine control device includes: a first detection unit for detecting the angles of the bucket, stick, and boom of the power excavator; a storage unit for storing the movement trajectory of the bucket tip when the digging resistance is low and the bucket is nearly full; a first control unit for controlling the bucket's posture based on the angle information of the bucket, stick, and boom detected by the detection unit and the movement trajectory information of the bucket tip read from the storage unit; a second detection unit for detecting when the digging resistance of the bucket reaches or exceeds a set value; and a unit for correcting the movement trajectory information of the bucket tip read from the storage unit in the direction of decreasing digging resistance based on the output of the second detection unit.

[0004] The engineering machinery described in Patent Documents 1 and 2 detects the digging reaction force (digging resistance) borne by the bucket from the ground during excavation operations, and corrects the bucket's forward direction upward when the detected digging reaction force (digging resistance) is large, so that the digging resistance decreases.

[0005] In the engineering machinery described in Patent Documents 1 and 2, as mentioned above, the determination of whether to reduce digging resistance during excavation operations is based solely on the digging reaction force. Therefore, the efficiency of the excavation operation may not be good. Specifically, for example, when the resistance (penetration resistance) when the bucket teeth enter the ground is high, the bucket's forward direction is corrected upwards to reduce digging resistance. In this case, the amount of sand in the bucket when the excavation is completed may sometimes be significantly reduced relative to the bucket's capacity. On the other hand, even if the amount of sand in the bucket reaches the bucket's capacity, for example, if the digging resistance of the bucket does not reach the set value due to soil conditions, the bucket's forward direction will continue to be maintained. In this case, even though the amount of sand in the bucket is sufficient, the bucket will continue to dig deeper into the ground, thus consuming excess energy. Therefore, the efficiency of the excavation operation of the engineering machinery described in Patent Documents 1 and 2 may not be good.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Publication No. 8-81977

[0009] Patent Document 2: Japanese Patent Publication No. 62-160325 Summary of the Invention

[0010] In view of the above problems, the purpose of the present invention is to provide an engineering machine that can suppress the increase of digging resistance and the decrease of digging efficiency during digging operations.

[0011] The provided construction machinery includes: a body; a working device comprising a boom undulatingly supported on the body, a stick rotatably supported on the boom, and a bucket supported on the stick, the bucket having a base end rotatably mounted on the stick (i.e., a bucket base end) and a distal end opposite the bucket base end (i.e., a bucket distal end), and having an inner surface defining a space for accommodating sand (i.e., a accommodating space); at least one operating device for actuating the working device to perform digging operations, the digging operations being performed as follows: while in a digging posture, maintaining at least a portion including the bucket distal end in contact with the ground... The device is configured to: a state in which the bucket is displaced relative to the land to excavate sand from the land, wherein the excavation posture is such that the base of the bucket is positioned higher than the distal end of the bucket and capable of excavating sand from the land; and a controller, wherein the controller determines the state of the sand contained in the bucket and, based on the determination of the state of the sand, outputs a resistance reduction command signal, the resistance reduction command signal being a command signal for causing the working device to operate by displacing the bucket in a resistance reduction direction, the resistance reduction direction being a direction that reduces the excavation resistance acting on the bucket. Attached Figure Description

[0012] Figure 1 This is a side view of a hydraulic excavator according to an embodiment of the present invention.

[0013] Figure 2 This is a block diagram representing the functional structure of the controller of the hydraulic excavator and its input and output signals.

[0014] Figure 3 This is a cross-sectional view of the bucket of the hydraulic excavator, illustrating an example of the bucket's resistance reduction action.

[0015] Figure 4 This is a cross-sectional view of the bucket of the hydraulic excavator, illustrating another example of the bucket's drag reduction action.

[0016] Figure 5This is a cross-sectional view of the bucket of the hydraulic excavator, which shows another example of the bucket's drag reduction action.

[0017] Figure 6 This is a cross-sectional view showing the bucket of the hydraulic excavator.

[0018] Figure 7 This is a flowchart representing the operational control actions of the controller.

[0019] Figure 8 This is a flowchart illustrating another example of the operational control actions of the controller.

[0020] Figure 9 This is a block diagram illustrating the functional structure and input / output signals of the controller of a hydraulic excavator involved in a variation of the described embodiment. Detailed Implementation

[0021] Embodiments of the present invention are described with reference to the accompanying drawings. Figure 1 This is a side view of the hydraulic excavator 10 according to this embodiment. Figure 1 As shown, the hydraulic excavator 10 includes: a lower traveling body 1, capable of traveling on land G; an upper slewing body 2, rotatably supported on the lower traveling body 1 about a rotation center axis Z facing vertically; and a working device 3, supported on the upper slewing body 2. The lower traveling body 1 and the upper slewing body 2 are examples of the machine body. Furthermore, in the attached drawings, "front" and "rear" refer to directions based on the orientation of the upper slewing body 2.

[0022] The lower traveling body 1 includes a pair of tracked traveling devices and a lower frame connecting these traveling devices. The upper slewing body 2 includes an upper frame rotatably supported on the lower frame, a driver's cab supported on the front of the upper frame, and a counterweight supported on the rear of the upper frame. In this embodiment, the working device 3 includes a boom 4, a stick 5, and a bucket 6.

[0023] The boom 4 is supported on the upper frame in a manner that allows it to undulate relative to the upper frame of the upper rotating body 2. Specifically, the boom 4 has a boom base end and a boom distal end. The boom base end is mounted on the base end of the upper frame in a manner that allows it to rotate in the upward and downward directions respectively with the horizontal axis A1 as the center. The boom distal end is the distal end located on the opposite side of the boom base end.

[0024] The stick 5 is supported on the boom 4 in a manner that allows it to rotate relative to the boom 4. Specifically, the stick 5 has a base end and a distal end. The base end is mounted on the base end of the boom in a manner that allows it to rotate about the horizontal axis A2 in both the retraction and push directions. The distal end is the distal end located on the opposite side of the base end. The retraction direction is the direction of rotation of the distal end of the stick 5 towards the machine body, and the push direction is the direction of rotation opposite to the retraction direction.

[0025] The bucket 6 is supported on the stick 5 in a manner rotatable relative to the stick 5. Specifically, the bucket 6 has a bucket base end 61 and a bucket distal end 62. The bucket base end 61 is mounted on the base end of the stick in a manner rotatable about a horizontal axis A3 in both the bucket retraction direction and the bucket push direction. The bucket distal end 62 is the distal end located on the opposite side of the bucket base end 61. The bucket retraction direction is, for example, in... Figure 1 As shown, when the bucket 6 is digging, the direction of rotation of the bucket distal end 62 is closer to the machine body, and the direction of pushing the bucket is the opposite of the direction of retracting the bucket.

[0026] The bucket 6 has a bucket body 6A including a bucket base end 61 and a plurality of bucket teeth 6B (a plurality of claws). The bucket body 6A constitutes the container portion of the bucket 6, having a space for holding sand, i.e., a receiving space. The bucket body 6A has an inner surface defining this receiving space. The plurality of bucket teeth 6B constitute the bucket distal end 62 of the bucket 6 and are fixed to the end of the bucket body 6A in a manner arranged along the width direction of the bucket body 6A. The width direction of the bucket body 6A is a direction parallel to the horizontal axis A3 and is a left-right direction. Each of the plurality of bucket teeth 6B protrudes from the end of the bucket body 6A in a direction orthogonal to the width direction.

[0027] For example, the angle of the bucket 6 relative to the stick 5 can be used to define the bucket retraction direction and the bucket push direction. Let the angle between straight lines L1 and L2 be defined as the bucket angle θ. Line L1 passes through the rotation center of the stick base end, i.e., the horizontal axis A2, and the rotation center of the bucket base end, i.e., the horizontal axis A3. Line L2 passes through the horizontal axis A3 and the distal end of the bucket 6 (the distal end of the bucket teeth 6B). In this case, the bucket retraction direction is the rotation direction in which the bucket angle θ decreases, and the bucket push direction is the rotation direction in which the bucket angle θ increases.

[0028] The hydraulic excavator 10 also includes multiple hydraulic actuators for moving the working device 3 hydraulically. The multiple hydraulic actuators include a boom cylinder 7, a stick cylinder 8, a bucket cylinder 9, and a swing motor 11.

[0029] Working cylinders 7, 8, and 9 are each composed of a hydraulic working cylinder, which extends and retracts upon receiving a supply of working oil. The boom working cylinder 7 is mounted on the upper slewing body 2 and the boom 4, causing the boom 4 to rise and fall with the extension and retraction of the boom working cylinder 7, i.e., to rotate the boom 4 in both the raising and lowering directions. The stick working cylinder 8 is mounted on the boom 4 and the stick 5, causing the stick 5 to rotate in both the retracting and pushing directions with the extension and retraction of the stick working cylinder 8. The bucket working cylinder 9 is mounted on the stick 5 and the bucket 6, causing the bucket 6 to rotate in both the retracting and pushing directions with the extension and retraction of the bucket working cylinder 9.

[0030] The rotary motor 11 is a hydraulic motor used to rotate the upper rotating body 2 relative to the lower traveling body 1 via hydraulic pressure. The rotary motor 11 has an output shaft connected to the upper frame of the upper rotating body 2 via a reducer (not shown). The rotary motor 11 operates by receiving a supply of working oil, causing the output shaft to rotate in a direction corresponding to the direction of the supply of working oil, thereby enabling the upper rotating body 2 to rotate in both the left and right rotation directions.

[0031] like Figure 2 As shown, the hydraulic excavator 10 also includes multiple operating devices, multiple sensors, and a controller 50.

[0032] Multiple operating devices are devices that enable the working device 3 to perform excavation operations, which are performed as follows: while the bucket 6 is in an excavation position, the bucket 6 is displaced relative to the land G while maintaining at least the portion including the distal end 62 of the bucket in contact with the land G, thereby excavating the sand and soil of the land G.

[0033] Multiple operating devices include a boom operating device 21, a stick operating device 22, and a bucket operating device 23. Each of these operating devices 21, 22, and 23 is comprised of an electric lever device, which has an operating lever. When an operator applies an operation to the operating lever to move the working device 3, an electrical signal, i.e., a lever signal, corresponding to that operation is input to the controller 50. Specifically, as described below.

[0034] The boom operating device 21 includes: a boom operating lever, which is operated by the operator to move the boom 4, i.e., boom operation; and a boom operation signal generation unit, which generates a lever signal corresponding to the boom operation applied to the boom operating lever, i.e., a boom operation signal, and inputs the boom operation signal to the controller 50.

[0035] The stick operation device 22 includes: a stick operation lever, which is operated by the operator to move the stick 5, i.e., stick operation; and a stick operation signal generation unit, which generates a stick signal corresponding to the stick operation applied to the stick operation lever, i.e., stick operation signal, and inputs the stick operation signal to the controller 50.

[0036] The bucket operating device 23 includes: a bucket operating lever, which is operated by the operator to move the bucket 6, i.e., bucket operation; and a bucket operation signal generating unit, which generates a lever signal corresponding to the bucket operation applied to the bucket operating lever, i.e., a bucket operation signal, and inputs the bucket operation signal to the controller 50.

[0037] Multiple sensors detect information necessary for the controller 50 to control the operation of the working device 3, and input the corresponding electrical signal, i.e., the detection signal, to the controller 50. The multiple sensors include a boom angle sensor 31, a stick angle sensor 32, a bucket angle sensor 33, multiple working cylinder pressure sensors 35, an image acquisition sensor 80 (image acquirer), and a body tilt angle sensor 34.

[0038] The boom angle sensor 31, stick angle sensor 32, and bucket angle sensor 33 are examples of a work device posture information acquirer that acquires information related to the posture of the work device 3, i.e., work device posture information. The image acquisition sensor 80 is an example of a sand information acquirer that acquires information related to the sand contained in the receiving space of the bucket 6, i.e., sand information.

[0039] The boom angle sensor 31 detects the angle of the boom 4 relative to the upper rotating body 2, i.e., the boom angle, and inputs the detection signal corresponding to the detected boom angle, i.e., the boom posture detection signal, to the controller 50. For example, Figure 1 As shown, the boom angle sensor 31 is disposed at the boom base end of the boom 4.

[0040] The stick angle sensor 32 detects the angle between the stick 5 and the boom 4, i.e., the stick angle, and inputs the detection signal corresponding to the detected stick angle, i.e., the stick posture detection signal, to the controller 50. For example, Figure 1 As shown, the stick angle sensor 32 is disposed at the stick base end of the stick 5.

[0041] The bucket angle sensor 33 detects the angle θ between the bucket 6 and the stick 5, and inputs the detection signal corresponding to the detected bucket angle θ, i.e., the bucket posture detection signal, to the controller 50. For example, Figure 1 As shown, the bucket angle sensor 33 is disposed at the bucket base end 61 of the bucket 6.

[0042] The boom angle sensor 31, stick angle sensor 32, and bucket angle sensor 33 can each be, for example, a resolver, a rotary encoder, a potentiometer, an IMU (Inertial Measurement Unit), or other sensors.

[0043] The tilt angle sensor 34 is a sensor used to detect the tilt angle of the machine body. The tilt angle sensor 34 is, for example, disposed on the upper rotating body 2, measures the tilt angle of the machine body relative to the horizontal plane, and inputs a detection signal corresponding to the detected tilt angle to the controller 50. The tilt angle sensor 34 may also be configured as an IMU.

[0044] The plurality of working cylinder pressure sensors 35 includes at least one working cylinder pressure sensor for detecting the pressure of the boom working cylinder 7, at least one working cylinder pressure sensor for detecting the pressure of the stick working cylinder 8, and at least one working cylinder pressure sensor for detecting the pressure of the bucket working cylinder 9. Specifically, in this embodiment, the plurality of working cylinder pressure sensors 35 includes a working cylinder pressure sensor for detecting the pressure of the head chamber of the boom working cylinder 7, a working cylinder pressure sensor for detecting the pressure of the rod chamber of the boom working cylinder 7, a working cylinder pressure sensor for detecting the pressure of the head chamber of the stick working cylinder 8, a working cylinder pressure sensor for detecting the pressure of the rod chamber of the stick working cylinder 8, a working cylinder pressure sensor for detecting the pressure of the head chamber of the bucket working cylinder 9, and a working cylinder pressure sensor for detecting the pressure of the rod chamber of the bucket working cylinder 9. Each of the plurality of working cylinder pressure sensors 35 inputs a detection signal, i.e., a pressure detection signal, corresponding to the detected pressure, to the controller 50.

[0045] Image acquisition sensor 80 acquires information related to the sand contained in the containment space of bucket 6, i.e., sand information, and inputs this sand information to controller 50. Image acquisition sensor 80 can measure the shape data of the inner surface of bucket 6 and the sand contained in bucket 6 (e.g., initial image information, excavation image information, etc., described later). Image acquisition sensor 80 may also be configured as a ranging sensor, which measures measurement data representing the distance to an object. The ranging sensor may also be, for example, a LiDAR (Light Detection and Ranging) sensor. LiDAR can illuminate an object with near-infrared light, visible light, ultraviolet light, etc., and use a light sensor to acquire the reflected light of the above light, thereby measuring the distance to the object. The ranging sensor may also be a TOF (Time of Flight) sensor or a stereo camera, etc., a sensor that can measure depth using multiple pixel units.

[0046] Image acquisition sensor 80 is configured to acquire sand information related to the sand contained in the containment space of bucket 6 during excavation operations. In excavation operations, for example, as... Figure 1 As shown, the bucket 6 moves in the following order: position before the start of the digging operation (pre-operation position P1), position during the digging operation (operation position P2), and position at the end of the digging operation (end position P3). In this embodiment, as... Figure 1 As shown, the image acquisition sensor 80 is disposed in the cab of the upper rotating body 2, and has a field of view (e.g., when the bucket 6 is in a range including the working position P2 and the end position P3) capable of capturing images of the inner surface of the bucket 6 and the sand contained in the bucket 6. Figure 1 (The field of view is represented by the double-dotted line). Furthermore, the image acquisition sensor 80 can be configured on the lower surface of the boom 4 or on the inner side of the stick 5. The lower surface of the boom 4 is one of the multiple surfaces of the boom 4. Figure 1 The inner surface of the stick 5, facing the land G, is one of the multiple surfaces of the stick 5. Figure 1 The face facing backwards.

[0047] The controller 50 controls the operation of the working device 3 based on operation signals input from multiple operating devices and detection signals input from multiple sensors. The controller 50 is a computer including a CPU (Central Processing Unit) and memory.

[0048] The controller 50 includes a bucket posture calculation unit 51, a sand volume calculation unit 52, a contact state determination unit 53, a digging reaction force calculation unit 54, a bucket forward direction determination unit 55, and a bucket forward direction control unit 56.

[0049] The bucket posture calculation unit 51 uses the posture information of the working device to calculate the posture of the bucket 6, i.e., the bucket posture. Specifically, the bucket posture calculation unit 51 calculates the bucket posture based on the boom posture detection signal input from the boom angle sensor 31, the stick posture detection signal input from the stick angle sensor 32, and the bucket posture detection signal input from the bucket angle sensor 33.

[0050] The sand volume calculation unit 52 uses the bucket posture and the sand information to calculate the accumulation state of the sand in the accommodating space of the bucket 6. The sand volume calculation unit 52 is an example of an accumulation state calculation unit.

[0051] The contact state determination unit 53 determines the contact state between a specific upper region 64 of the inner surface of the bucket 6 and the sand. In this embodiment, the contact state determination unit 53 determines the contact state based on the accumulation state calculated by the sand quantity calculation unit 52. The contact state determination unit 53 stores data representing the determination result of the contact state in a designated area (FLAG, status flag register) of the memory. The contact state determination unit 53 is an example of a state determination unit.

[0052] The specific upper region 64 is the upper portion of the inner surface of the bucket 6 in the digging posture. For example... Figure 1 As shown, the digging posture is the posture in which the bucket 6 is positioned with the base end 61 of the bucket higher than the far end 62 of the bucket. In this posture, just as when the bucket 6 is positioned in the working position P2 and the end position P3, the opening of the bucket 6 faces the rear, and the bucket 6 is able to dig the sand and soil of the land G.

[0053] like Figure 1 As shown, the bucket 6 includes: an upper plate 65, located at the top in the digging posture; a lower plate 66, located at the bottom in the digging posture; a bottom plate 68, bent to connect the upper plate 65 and the lower plate 66; a right plate (not shown), connected to the right edge of the upper plate 65, the right edge of the bottom plate 68, and the right edge of the lower plate 66; and a left plate 67, connected to the left edge of the upper plate 65, the left edge of the bottom plate 68, and the left edge of the lower plate 66. The inner surface of the bucket 6 includes the inner side of the upper plate 65, the inner side of the bottom plate 68, and the inner side of the lower plate 66, but excludes the inner side of the right plate and the inner side of the left plate. For example, as... Figure 3 As shown in the figure above, the specific upper region 64 is the portion of the inner surface of the bucket 6 that is located higher than the boundary portion PS of the bucket 6. In this embodiment, the boundary portion PS is the portion located at the foremost side of the inner surface of the bucket 6 in the digging posture. Therefore, the boundary portion PS is a part that changes according to the posture of the bucket 6. The contact state determination unit 53 can calculate the position of the boundary portion PS based on the bucket posture calculated by the bucket posture calculation unit 51. In addition, the boundary portion PS may also be a predetermined specific part (fixed part) and not a part that changes according to the posture of the bucket 6. When the boundary portion PS is a fixed part, the boundary portion PS may, for example, be the lowermost part (bottom) when the opening of the bucket 6 is horizontally arranged on the horizontal plane. In addition, the boundary portion PS may be set on a horizontal straight line parallel to the width direction of the bucket 6, from the left end to the right end of the inner surface, or it may be set at different heights in each region according to multiple regions in the width direction. The boundary PS does not necessarily have to be set from the left end to the right end of the inner surface; it can also be set only for a portion of the area in the width direction.

[0054] The excavation reaction force calculation unit 54 calculates the excavation reaction force based on the tilt angle of the machine body (posture of the upper rotating body 2) detected by the body tilt angle sensor 34, the posture of the working device 3 (posture of the boom 4, posture of the stick 5, and posture of the bucket 6) detected by the boom angle sensor 31, the stick angle sensor 32, and the bucket angle sensor 33, the pressure of the boom working cylinder 7, the stick working cylinder 8, and the bucket working cylinder 9 detected by the multiple working cylinder pressure sensors 35, and dimensional information related to the dimensions between the connecting rods in the working device 3. The dimensions between the connecting rods are pre-stored in the storage unit of the controller 50, including, for example, the distance between the horizontal axis A1 and the horizontal axis A2, and the distance between the horizontal axis A2 and the horizontal axis A3. The body tilt angle sensor 34, the boom angle sensor 31, the stick angle sensor 32, the bucket angle sensor 33, and the multiple working cylinder pressure sensors 35 are examples of an excavation reaction force measuring device.

[0055] The bucket forward direction determination unit 55 and the bucket forward direction control unit 56 are examples of a working device control unit. Based on the determination result of the contact state determination unit 53, the working device control unit outputs a resistance reduction command signal. This resistance reduction command signal is a command signal used to cause the working device 3 to operate by displacing the bucket 6 in a resistance reduction direction, which is a direction that reduces the digging resistance acting on the bucket 6. Specifically, as described below.

[0056] The bucket forward direction determination unit 55 determines whether it is necessary to control the forward direction of the bucket 6 to reduce the digging resistance acting on the bucket 6. In this embodiment, the bucket forward direction determination unit 55 determines whether it is necessary to reduce the digging resistance acting on the bucket 6 based on the determination result (determination FLAG) of the contact state determination unit 53, the bucket posture calculated by the bucket posture calculation unit 51, and the digging reaction force calculated by the digging reaction force calculation unit 54.

[0057] The bucket forward direction control unit 56 outputs a command signal to activate the working device 3 based on the lever signals input from multiple operating devices and the determination result of the bucket forward direction determination unit 55. Specifically, the bucket forward direction control unit 56 outputs a command signal to activate the working device 3 based on the boom operation signal input from the boom operating device 21, the stick operation signal input from the stick operating device 22, the bucket operation signal input from the bucket operating device 23, and the determination result of the bucket forward direction determination unit 55.

[0058] When the bucket forward direction determination unit 55 determines that it is unnecessary to reduce the digging resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a command signal corresponding to the boom operation signal, stick operation signal, and bucket operation signal to the working device drive unit. Conversely, when the bucket forward direction determination unit 55 determines that it is necessary to reduce the digging resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a resistance reduction command signal to the working device drive unit. This resistance reduction command signal is a command signal used to operate the working device 3 by displacing the bucket 6 in a resistance reduction direction, which is the direction that reduces the digging resistance acting on the bucket 6. The resistance reduction command signal includes a correction command signal that corrects at least one of the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal.

[0059] The operating device drive unit includes multiple proportional valves and control valve units 77. The multiple proportional valves include a pair of boom proportional valves 71 and 72, a pair of stick proportional valves 73 and 74, and a pair of bucket proportional valves 75 and 76. Each of the proportional valves 71 to 76 is, for example, a solenoid proportional valve. The control valve unit 77 includes a boom control valve, a stick control valve, and a bucket control valve.

[0060] The control valve unit 77 is located between a hydraulic pump (not shown) and multiple hydraulic actuators, and regulates the flow rate and supply direction of the working oil supplied to the multiple hydraulic actuators respectively.

[0061] Specifically, the control valve unit 77 includes: a boom control valve for regulating the flow rate and direction of the working oil supplied to the boom cylinder 7; a stick control valve for regulating the flow rate and direction of the working oil supplied to the stick cylinder 8; and a bucket control valve for regulating the flow rate and direction of the working oil supplied to the bucket cylinder 9.

[0062] When the bucket forward direction determination unit 55 determines that it is unnecessary to reduce the digging resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal to multiple proportional valves 71 to 76 of the working device drive unit. Specifically, as described below.

[0063] If the boom operation signal is input from the boom operating device 21, the bucket forward direction control unit 56 inputs a command signal corresponding to the boom operation signal, i.e., a boom command signal, to the boom proportional valve corresponding to the operating direction of the boom operation in one of the pair of boom proportional valves 71 and 72. As a result, the pilot pressure, reduced in the boom proportional valve according to the boom command signal, is input to one of the pilot ports of the boom control valve. Consequently, the hydraulic pump's working oil is supplied at a flow rate corresponding to the boom command signal to one of the head side chamber and rod side chamber of the boom cylinder 7 corresponding to the boom command signal. Therefore, the boom 4 rotates at a speed corresponding to the boom command signal in the direction corresponding to the boom command signal.

[0064] If the stick operation signal is input from the stick operation device 22, the bucket forward direction control unit 56 inputs a command signal corresponding to the stick operation signal, i.e., a stick command signal, to the stick proportional valve corresponding to the operating direction of the stick operation in one of the pair of stick proportional valves 73 and 74. As a result, a pilot pressure, reduced in pressure in the stick proportional valve according to the stick command signal, is input to one of the pilot ports of the stick control valve. Consequently, the hydraulic pump's working oil is supplied at a flow rate corresponding to the stick command signal to one of the head side chamber and stick side chamber of the stick working cylinder 8 corresponding to the stick command signal. Therefore, the stick 5 rotates at a speed corresponding to the stick command signal in the direction corresponding to the stick command signal.

[0065] If the bucket operation signal is input from the bucket operating device 23, the bucket forward direction control unit 56 inputs a command signal corresponding to the bucket operation signal, i.e., a bucket command signal, to the bucket proportional valve corresponding to the operating direction of the bucket operation in one of the pair of bucket proportional valves 75 and 76. As a result, a pilot pressure, reduced in pressure in the bucket proportional valve according to the bucket command signal, is input to one of the pilot ports of the bucket control valve. Consequently, the hydraulic pump's working oil is supplied at a flow rate corresponding to the bucket command signal to one of the head side chamber and rod side chamber of the bucket working cylinder 9 corresponding to the bucket command signal. Therefore, the bucket 6 rotates at a speed corresponding to the bucket command signal in the direction corresponding to the bucket command signal.

[0066] On the other hand, when the bucket forward direction determination unit 55 determines that it is necessary to reduce the digging resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a resistance reduction command signal to the working device drive unit. This resistance reduction command signal is a command signal used to cause the working device 3 to operate by moving the bucket 6 in the resistance reduction direction. The resistance reduction direction is the direction that can reduce the digging resistance acting on the bucket 6.

[0067] Figure 3 This is an example of the action that reduces the resistance of bucket 6. Figure 4 Another example of the drag reduction action of bucket 6, Figure 5 This is another example of the action that reduces the resistance of bucket 6. Figure 3 , Figure 4 and Figure 5 The common feature of the drag-reducing actions shown is that the forward direction of bucket 6 is corrected to the upward side. Furthermore, Figures 3-5 The cross-section of bucket 6 is parallel to the vertical direction.

[0068] First of all, Figure 3 The action of reducing resistance shown is explained. Figure 3 The diagram above illustrates a state where, during excavation, the bucket 6 moves in a direction close to the horizontal, i.e., direction D1. In this state, if the bucket forward direction determination unit 55 determines that it is necessary to reduce the excavation resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a resistance reduction command signal to the working device drive unit. This resistance reduction command signal is used to cause the working device 3 to operate by changing the forward direction of the bucket 6 from direction D1 to direction D2. Direction D2 is an upward-sloping direction with an increased proportion of the upward component compared to direction D1.

[0069] In such Figure 3 When the forward direction of the bucket 6 is changed in this way, in this embodiment, the bucket forward direction control unit 56 directly outputs (without correction) the stick command signal corresponding to the stick operation signal, and outputs a resistance reduction command signal after correcting the boom command signal corresponding to the boom operation signal and the bucket command signal corresponding to the bucket operation signal. That is, in this embodiment, when... Figure 3 In the state shown in the diagram above, when the bucket forward direction determination unit 55 determines that it is necessary to reduce the digging resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a command signal to multiple proportional valves 71-76. This causes the stick 5 to perform an action corresponding to the operator's stick operation, while the boom 4 does not perform a rotational action corresponding to the operator's boom operation. Instead, compared to the action corresponding to the boom operation, the boom 4 moves further in the boom raising direction. The bucket 6 does not perform an action corresponding to the operator's bucket operation. Instead, compared to the action corresponding to the bucket operation, the bucket 6 moves further in the bucket retraction direction. As a result, the forward direction of the bucket 6 changes from the first direction D1 to the second direction D2, thus reducing the digging resistance acting on the bucket 6.

[0070] Next, regarding Figure 4 The action of reducing resistance shown is explained. Figure 4The left figure illustrates a state where, during excavation, the bucket 6 moves, for example, in a direction close to the horizontal, i.e., the first direction D1. In this state, if the bucket forward direction determination unit 55 determines that it is necessary to reduce the excavation resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a resistance reduction command signal to the working device drive unit. This resistance reduction command signal is a command signal used to change the forward direction of the bucket 6 from the first direction D1 to the third direction D3, thereby causing the working device 3 to operate. The third direction D3 is a direction in which the upward component is proportionally increased compared to the first direction D1. Figure 4 In the central diagram, the third direction D3 is the upward direction.

[0071] In such Figure 4 In this embodiment, when the forward direction of the bucket 6 is changed from the left diagram to the central diagram, the bucket forward direction control unit 56 directly outputs (without correction) the stick command signal corresponding to the stick operation signal and the bucket command signal corresponding to the bucket operation signal, and outputs a resistance reduction command signal after correcting the boom command signal corresponding to the boom operation signal. That is, in this embodiment, when... Figure 4 In the state shown in the left figure, when the bucket forward direction determination unit 55 determines that it is necessary to reduce the digging resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a command signal to multiple proportional valves 71-76. This causes the stick 5 and bucket 6 to perform actions corresponding to the operator's stick operation and bucket operation, respectively. The boom 4 does not perform the rotation action corresponding to the operator's boom operation, but instead moves further in the boom lifting direction compared to the action corresponding to the boom operation. As a result, the forward direction of the bucket 6 changes from the first direction D1 to the third direction D3, thus reducing the digging resistance acting on the bucket 6.

[0072] If the predetermined conditions are met, the bucket forward direction control unit 56 directly outputs a boom command signal corresponding to the boom operation signal, a stick command signal corresponding to the stick operation signal, and a bucket command signal corresponding to the bucket operation signal. As a result, the boom 4, stick 5, and bucket 6 perform actions corresponding to the operator's boom operation, stick operation, and bucket operation, respectively. Therefore, if... Figure 4As shown in the right figure, the forward direction of the bucket 6 changes from the third direction D3 to the first direction D1 or a direction close to the first direction D1. The predetermined condition could be, for example, that the elapsed time from when the forward direction of the bucket 6 changes from the first direction D1 to the third direction D3 is a predetermined time. Alternatively, the predetermined condition could be, for example, that the distance traveled towards the third direction D3, calculated from when the forward direction of the bucket 6 changes from the first direction D1 to the third direction D3, reaches a predetermined distance. Furthermore, the predetermined condition could also be, for example, that the rotation angle of the boom 4, calculated from when the forward direction of the bucket 6 changes from the first direction D1 to the third direction D3, reaches a predetermined angle.

[0073] Next, regarding Figure 5 The action of reducing resistance shown is explained. Figure 5 The diagram above illustrates a state where, during excavation, the bucket 6 moves, for example, in a direction close to the horizontal, namely, the first direction D1. In this state, if the bucket forward direction determination unit 55 determines that it is necessary to reduce the excavation resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a resistance reduction command signal to the working device drive unit. This resistance reduction command signal is used to operate the working device 3 in a manner that completes the excavation operation. Specifically, the bucket forward direction control unit 56 outputs a resistance reduction command signal to the working device drive unit. This resistance reduction command signal is used to operate the working device 3 in a manner that changes the forward direction of the bucket 6 from the first direction D1 to the fourth direction D4. The fourth direction D4 is a direction in which the upward component is proportionally increased compared to the first direction D1. Figure 5 In the diagram below, the fourth direction D4 is the upward or diagonal direction away from the land G.

[0074] In such Figure 5 When the forward direction of the bucket 6 is changed from the upper diagram to the lower diagram, in this embodiment, the bucket forward direction control unit 56 outputs a resistance reduction command signal after correcting the boom command signal corresponding to the boom operation signal, the stick command signal corresponding to the stick operation signal, and the bucket command signal corresponding to the bucket operation signal. That is, in this embodiment, when... Figure 5In the state shown in the diagram above, when the bucket forward direction determination unit 55 determines that it is necessary to reduce the digging resistance acting on the bucket 6, the bucket forward direction control unit 56 outputs a command signal to multiple proportional valves 71-76. This causes the boom 4, stick 5, and bucket 6 to not perform rotational movements corresponding to the operator's boom, stick, and bucket operations, but instead the bucket 6 moves in the direction away from the ground G. As a result, the forward direction of the bucket 6 changes from the first direction D1 to the fourth direction D4, thus reducing the digging resistance acting on the bucket 6.

[0075] In this embodiment, the bucket posture calculation unit 51 includes a tilt angle calculation unit. The tilt angle calculation unit calculates a tilt angle index value, which is as follows: Figure 6 As shown, the index value corresponds to the inclination of a specific upper region 64 relative to a predetermined reference plane H. In this embodiment, the reference plane H is a horizontal plane, and the inclination index value is the angle θ1 of the upper plate 65 of the bucket 6 relative to the reference plane H. In this embodiment, a portion of the upper plate 65 is flat (in... Figure 6 Since the upper plate 65 is straight in cross-section, the angle between the flat portion of the upper plate 65 and the reference plane H can be set as θ1. However, the upper plate 65 can also be bent as a whole. When the upper plate 65 has a bent shape, the inclination index value can be, for example, the angle between the tangent at a predetermined location of the upper plate 65 and the reference plane H.

[0076] If the angle θ1 of the upper plate 65 calculated by the tilt calculation unit is greater than a predetermined threshold, i.e., the tilt threshold, the working device control unit does not output the resistance reduction command signal. The posture of the bucket 6 during digging operations is highly correlated with the magnitude of digging resistance. Specifically, for example, when the tilt of a specific upper region 64 relative to the horizontal plane H is large, the digging resistance tends to decrease; conversely, when the tilt of a specific upper region 64 relative to the horizontal plane H is small, the digging resistance tends to increase. Therefore, when the angle θ1 of the upper plate 65 is greater than the tilt threshold, there is a high probability that control to reduce digging resistance is not needed during digging operations, and in this case, the resistance reduction command signal is not output. This reduces the processing load on the controller 50.

[0077] Figure 7 This is a flowchart illustrating the operational control actions of the controller 50. The controller 50 receives input signals from lever signals from multiple operating devices 21 to 23 (step S11). In addition, the controller 50 receives input signals from sand information from the image acquisition sensor 80, pressure detection signals from multiple working cylinder pressure sensors 35, and posture detection signals from angle sensors 31 to 34.

[0078] Next, the bucket posture calculation unit 51 calculates the bucket posture based on the boom posture detection signal, the stick posture detection signal, and the bucket posture detection signal (step S12). In addition, the tilt angle calculation unit of the bucket posture calculation unit 51 calculates the angle θ1 of the upper plate 65 of the bucket 6 relative to the reference plane H based on the boom posture detection signal, the stick posture detection signal, and the bucket posture detection signal (step S12).

[0079] Next, the sand and soil quantity calculation unit 52 uses the bucket posture and the sand and soil information to calculate the accumulation state of the sand and soil in the accommodating space of the bucket 6 (step S13).

[0080] Next, the bucket forward direction determination unit 55 determines whether the angle θ1 of the upper plate 65 of the bucket 6 is less than a predetermined threshold, i.e., the tilt threshold (step S14).

[0081] If the angle θ1 of the upper plate 65 is above the tilt threshold (step S14 is "No"), the bucket forward direction determination unit 55 determines that it is not necessary to reduce the digging resistance acting on the bucket 6, and the bucket forward direction control unit 56 does not correct the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal (step S19). In this case, the bucket forward direction control unit 56 outputs the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal to the working device drive unit (step S17).

[0082] On the other hand, if the angle θ1 of the upper plate 65 is less than the tilt threshold (step S14 is "yes"), the contact state determination unit 53 determines the contact state based on the accumulation state calculated by the sand quantity calculation unit 52 (step S15).

[0083] Specifically, the sand volume calculation unit 52 (accumulation state calculation unit) can, in step S13, use, for example, the bucket posture and the sand information to calculate, for example, the accumulation state of the sand in the accommodating space of the bucket 6 in the following manner: That is, the sand volume calculation unit 52 can calculate, for example, the accumulation state of the sand in the accommodating space of the bucket 6 by comparing information about the initial image (initial image information) and information related to the image inside the bucket 6 acquired by an image acquisition sensor 80 such as LiDAR during the excavation operation (excavation image information). Figure 3 The portion PA where the inner surface of the bucket 6 intersects with the upper surface of the sand shown. Figure 3The initial image is the position of the intersection point PA in the cross-sectional view. It is an image of the bucket 6 in a non-containing state, where the bucket 6's accommodating space is empty of any objects such as sand or soil. For example, the sand / soil quantity calculation unit 52 can convert the initial image information to correspond to the bucket posture when acquiring the excavation image information, so as to compare the initial image information with the excavation image information. Next, the contact state determination unit 53 can determine the contact state by determining whether the calculated portion PA is within a specific upper region 64 on the inner surface of the bucket 6. The initial image information can also be information pre-stored in the memory of the controller 50. Alternatively, the initial image information can also be information acquired by the image acquisition sensor 80 before or at the start of the excavation operation.

[0084] Furthermore, the sand and soil volume calculation unit 52 can also calculate the position of the portion PA where the inner surface of the bucket 6 intersects with the upper surface of the sand and soil at a predetermined specific width-direction position, such as the center of the inner surface of the bucket 6 in the width direction. Additionally, a ranging sensor such as LiDAR can acquire data corresponding to the portion PA where the inner surface of the bucket 6 intersects with the upper surface of the sand and soil at multiple width-direction positions. In this case, the contact state determination unit 53 can also calculate the average value of the positions of the portions PA where the inner surface of the bucket 6 intersects with the upper surface of the sand and soil at the multiple width-direction positions, and use this average value to determine the contact state. Furthermore, the contact state determination unit 53 can also calculate the minimum or maximum value of the positions of the portions PA where the inner surface of the bucket 6 intersects with the upper surface of the sand and soil at the multiple width-direction positions, and use this minimum or maximum value to determine the contact state.

[0085] If the contact state determination unit 53 determines that the sand is in contact with a specific upper region 64 (upper surface of the bucket 6) of the bucket 6 (step S15 is "yes"), the bucket forward direction determination unit 55 determines that it is necessary to reduce the digging resistance acting on the bucket 6, and the bucket forward direction control unit 56 corrects at least one of the command signals corresponding to the boom operation signal, stick operation signal and bucket operation signal (step S16).

[0086] The command signal can also be modified according to the pre-set movement pattern (target path) of the bucket 6 corresponding to the resistance reduction action performed by the bucket 6. For example, the hydraulic excavator 10 may also be equipped with an input device that allows the operator to select the appropriate input at the start of the excavation operation. Figure 3 , Figure 4 and Figure 5The drag reduction action is the drag reduction action performed by the bucket 6 during digging operations. In this case, in step S16, the bucket forward direction control unit 56 corrects at least one of the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal in a way that causes the bucket 6 to move according to a predetermined movement mode corresponding to the drag reduction action selected by the operator (step S16), and outputs a command signal containing the corrected command signal, i.e., the drag reduction command signal, to a plurality of proportional valves 71 to 76 (step S17). As a result, the bucket 6 moves in the direction that reduces the digging resistance acting on the bucket 6, i.e., the drag reduction direction.

[0087] On the other hand, if the contact state determination unit 53 determines that the sand is not in contact with the specific upper area 64 of the bucket 6 (step S15 is "No"), the digging reaction force calculation unit 54 calculates the digging reaction force based on the detection signal input from the body tilt angle sensor 34, the detection signals input from the boom angle sensor 31, the stick angle sensor 32 and the bucket angle sensor 33, the pressure detection signal input from the multiple working cylinder pressure sensors 35, and the size information related to the size between the connecting rods in the working device 3. The bucket forward direction determination unit 55 determines whether the calculated digging reaction force is greater than a predetermined threshold, i.e., the reaction force threshold (step S18).

[0088] When the digging reaction force exceeds the reaction force threshold (step S18 is "Yes"), the bucket forward direction determination unit 55 determines that it is necessary to reduce the digging resistance acting on the bucket 6. The bucket forward direction control unit 56 corrects at least one of the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal (step S16), and outputs a command signal containing the corrected command signal, i.e., the resistance reduction command signal, to the plurality of proportional valves 71 to 76 (step S17). As a result, the bucket 6 is displaced in the direction that reduces the digging resistance acting on the bucket 6, i.e., the resistance reduction direction.

[0089] On the other hand, if the digging reaction force is below the reaction force threshold (step S18 is "No"), the bucket forward direction determination unit 55 determines that it is not necessary to reduce the digging resistance acting on the bucket 6, and the bucket forward direction control unit 56 does not correct the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal (step S19). In this case, the bucket forward direction control unit 56 outputs the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal to the working device drive unit (step S17).

[0090] Figure 8 This is another flowchart illustrating the operational control actions of controller 50. Figure 8The processing of steps S31 to S33 in the process and Figure 7 The processing of steps S11 to S13 is the same, in addition, Figure 8 The processing of steps S34-S36 and S38 in the process and Figure 7 The processes in steps S15-S17 and S19 are the same; therefore, detailed explanations related to these processes are omitted. Additionally, in Figure 8 The operation control action shown includes step S37, but the following is omitted. Figure 7 The processing of steps S14 and S18 in the above. Therefore, the following mainly describes the content related to step S37.

[0091] exist Figure 8 In the illustrated operation control, if the contact state determination unit 53 determines that the sand is not in contact with the specific upper region 64 (upper surface of the bucket 6) of the bucket 6 (step S34 is "No"), the bucket forward direction determination unit 55 determines whether the amount of sand in the bucket 6 is greater than a predetermined threshold, i.e., the sand amount threshold (step S37). The bucket forward direction determination unit 55 can, for example, determine (calculate) the amount of sand in the bucket 6 based on the intersecting portion PA (the intersection point PA) calculated by the sand amount calculation unit 52. Specifically, for example, the controller 50 may pre-store a map representing the relationship between the position of the intersecting portion PA (the intersection point PA) and the amount of sand in the bucket 6. The bucket forward direction determination unit 55 can calculate the amount of sand in the bucket 6 based on the intersecting portion PA (the intersection point PA) calculated by the sand amount calculation unit 52 and the map. The sand volume threshold can also be set to a value that can prevent the sand volume in the bucket from decreasing significantly relative to the bucket capacity when excavation is completed, and can also prevent the consumption of excess energy.

[0092] When the amount of sand exceeds a sand volume threshold (step S37 is "Yes"), the bucket forward direction determination unit 55 determines that it is necessary to reduce the digging resistance acting on the bucket 6. The bucket forward direction control unit 56 corrects at least one of the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal (step S35), and outputs a command signal containing the corrected command signal, i.e., the resistance reduction command signal, to multiple proportional valves 71 to 76 (step S36). As a result, the bucket 6 moves in the direction that reduces the digging resistance acting on the bucket 6, i.e., the resistance reduction direction.

[0093] On the other hand, if the amount of sand is below the sand amount threshold (step S37 is "No"), the bucket forward direction determination unit 55 determines that it is not necessary to reduce the digging resistance acting on the bucket 6, and the bucket forward direction control unit 56 does not correct the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal (step S38). In this case, the bucket forward direction control unit 56 outputs the command signals corresponding to the boom operation signal, stick operation signal, and bucket operation signal to the working device drive unit (step S36).

[0094] Figure 9 This is a block diagram illustrating the functional structure and input / output signals of the controller 50 of the hydraulic excavator 10 according to a modified embodiment of this invention. The hydraulic excavator 10 according to this modified embodiment includes a load detector 82 instead of... Figure 2 The block diagram shown shows the image acquisition sensor 80. The load detector 82 is another example of a sand information acquirer that acquires information related to the sand contained in the containment space of the bucket 6, i.e., sand information.

[0095] A load detector 82 is disposed in a specific upper region 64 on the inner surface of the bucket 6 and is a sensor capable of detecting the load, i.e., the sand load, borne by the sand contained in the accommodating space of the bucket 6. Specifically, the load detector 82 is installed in at least a portion of the specific upper region 64. For example, a strain gauge, a pressure-sensitive sensor, or a load cell can be used as the load detector 82. The load detector 82 inputs a detection signal, i.e., a load detection signal, corresponding to the detected sand load, to the controller 50.

[0096] The contact state determination unit 53 determines the contact state between a specific upper region 64 and the sand based on the sand load detected by the load detector 82. Specifically, the contact state determination unit 53 may, for example, determine that the sand is in contact with the specific upper region if the sand load detected by the load detector 82 is above a predetermined threshold. In this modified example, the contact state between the specific upper region 64 and the sand is determined based on the sand load detected by the load detector 82, therefore, for example, as... Figure 2 Compared to the case where the contact state is determined based on image processing data (dot matrix data), as shown in the block diagram of LiDAR and other image acquisition sensors 80, the increased processing load on the controller 50 can be suppressed.

[0097] As described above, the hydraulic excavator 10 of this embodiment determines whether to control the digging resistance during the digging operation based on the contact state between a specific upper region 64 of the inner surface of the bucket 6 and the sand. Therefore, it can suppress the increase of digging resistance during the digging operation and suppress the decrease of digging efficiency.

[0098] When the sand information acquirer is a sensor that directly detects the load borne by the sand in contact with the inner surface of the bucket 6 (e.g., a sensor like the load detector 82 described above), the contact state determination unit 53 can directly determine the contact state between a specific upper region 64 and the sand based on the detection signal input from the sensor to the controller 50. Alternatively, when the sand information acquirer is, for example, a sensor like the image acquisition sensor 80 described above, the contact state determination unit 53 can indirectly determine the contact state (estimate the contact state) between a specific upper region 64 and the sand based on sand information such as image information input from the sensor to the controller 50.

[0099] In this embodiment, when the contact state determination unit 53 determines that the sand is in contact with a specific upper area 64 of the bucket 6, the working device control unit outputs the resistance reduction command signal, causing the bucket 6 to move in the resistance reduction direction to reduce digging resistance. Therefore, the amount of sand in the bucket 6 can be fully ensured during digging operations.

[0100] In this embodiment, when the contact state determination unit 53 determines that the sand is not in contact with the specific upper region 64 of the bucket 6, and the amount of sand contained in the accommodating space of the bucket 6 is greater than a predetermined threshold, i.e., the sand quantity threshold, the operating device control unit outputs the resistance reduction command signal. During excavation, even if the sand in the bucket 6 is not in contact with the specific upper region 64, if the amount of sand in the bucket 6 becomes greater than the sand quantity threshold, the resistance reduction command signal is output. Therefore, before the sand in the bucket 6 comes into contact with the specific upper region 64 and causes an increase in excavation resistance, the bucket 6 can be moved in the resistance reduction direction to reduce excavation resistance. This suppresses the consumption of excess energy.

[0101] In this embodiment, when the contact state determination unit determines that the sand is not in contact with the specific upper region 64 of the bucket 6, and the digging reaction force is greater than the reaction force threshold, the operating device control unit outputs the resistance reduction command signal. In this embodiment, the reaction force threshold is set to a value that can suppress the situation where the digging reaction force increases and the speed of the bucket 6's movement decreases significantly. If the movement speed of the bucket 6 decreases significantly, the efficiency of the digging operation will decrease. In this embodiment, even when the sand in the bucket 6 is not in contact with the specific upper region 64, if the digging reaction force is greater than the reaction force threshold, the bucket 6 is moved in the resistance reduction direction to reduce digging resistance, thus further suppressing the decrease in the efficiency of the digging operation.

[0102] In this embodiment, the contact state determination unit 53 determines the contact state between the specific upper region 64 and the sand based on the accumulation state calculated by the sand quantity calculation unit 52, which is an example of the accumulation state calculation unit. That is, in this embodiment, the contact state between the specific upper region 64 and the sand can be determined based on the actual accumulation state of the sand in the bucket 6.

[0103] In a variation of this embodiment, the contact state determination unit 53 determines the contact state between a specific upper region 64 and the sand based on the sand load detected by the load detector 82. Therefore, for example, compared with the case where the contact state is determined based on image processing data, the increase in the processing load of the controller 50 can be suppressed.

[0104] In this embodiment, if the tilt index value calculated by the tilt angle calculation unit of the bucket posture calculation unit 51 is greater than the tilt angle threshold, the working device control unit does not output the resistance reduction command signal. When the tilt index value is greater than the tilt angle threshold, there is a high probability that control to reduce digging resistance is not needed during digging operations; in this case, the resistance reduction command signal is not output. This reduces the processing load on the controller 50.

[0105] [Variation Example]

[0106] The above describes the engineering machinery involved in the embodiments of the present invention, but the present invention is not limited to the embodiments described herein, and includes, for example, the following variations.

[0107] (A) Regarding the operating device

[0108] In the described embodiment, although each of the multiple operating devices (operating devices 21, 22, 23) is configured with an electric control lever, it is not limited to this configuration. Each of the multiple operating devices may also be an operating device comprising an operating lever and a remote control valve. In this case, the remote control valve of each of the multiple operating devices is located between a pilot pump (not shown) and a pair of pilot ports of a control valve corresponding to the remote control valve. The remote control valve operates by supplying a pilot pressure corresponding to the operating amount of the operating lever to the pilot port corresponding to the operating direction of the operating lever. This regulates the flow rate and direction of the working oil supplied to the working cylinder corresponding to the operating device. In this case, each of the proportional valves 71 to 76 may also be configured between the pilot ports of the remote control valve and the control valve corresponding to the proportional valve.

[0109] (B) Regarding the posture information acquisition device of the working device

[0110] The posture information acquisition device for the working device can also be, for example, multiple stroke sensors. These multiple stroke sensors include a boom cylinder stroke sensor that detects the length of the boom cylinder 7, a stick cylinder stroke sensor that detects the length of the stick cylinder 8, and a bucket cylinder stroke sensor that detects the length of the bucket cylinder 9. Each of the multiple stroke sensors inputs a detection signal corresponding to the detected cylinder length to the controller 50. The controller 50 pre-stores dimensional information related to the dimensions between the links in the working device 3, dimensional information related to the installation position of each cylinder, etc. The dimensions between the links include, for example, the distance between horizontal axis A1 and horizontal axis A2, and the distance between horizontal axis A2 and horizontal axis A3. Based on the cylinder lengths from the multiple stroke sensors and the dimensional information, the relative angles between the machine body and boom 4, boom 4 and stick 5, stick 5 and bucket 6, and the posture of the working device 3 can be calculated geometrically. Therefore, the bucket posture calculation unit 51 can calculate the posture of the bucket 6 geometrically based on the detection signals input from multiple stroke sensors and the dimensional information.

[0111] (C) The engineering machinery involved in this invention can also be applied to (1) machine control assisting the operator in excavation operations, (2) remote operation of the hydraulic excavator 10 by the operator, (3) automatic (e.g., fully automatic) hydraulic excavator 10, etc.

[0112] (1) Regarding machine control

[0113] In the case of machine control, at least one operating device for activating the working device to perform excavation work can be an operating switch or similar device located in the cab and operable by the operator, or it can be any one of the plurality of operating devices (e.g., a stick operating device). This machine control refers to the controller 50 automatically controlling the operation of the working device 3 in a manner that causes the bucket 6 to move along the target excavation face of the bucket 6 in a pre-stored excavation operation in the controller 50's memory. In this case, if the operator's input is input to the operating device, the controller 50 executes machine control that causes the working device 3 to operate, performing an excavation operation to excavate the land at the work site in a shape corresponding to the target excavation face. During the excavation operation using this machine control, the working device control unit outputs a resistance reduction command signal based on the determination result of the contact state determination unit, causing the working device to operate by moving the bucket in the resistance reduction direction.

[0114] Actual site conditions include various situations that the personnel involved in the operation cannot grasp before the operation. Therefore, in the machine control described above, if the controller 50 automatically controls the operation of the working device 3 by displacing the bucket 6 along a pre-stored target digging surface, it may not be possible to perform efficient digging operations. Even in this case, if the working device control unit performs control such as outputting a resistance reduction command signal based on the determination result of the contact state determination unit, the bucket 6 can be moved in a way that matches the actual site conditions, thereby enabling efficient digging operations.

[0115] (2) Regarding remote operation

[0116] In the case where the excavation operation of the hydraulic excavator 10 is remotely operated by an operator, the construction machinery includes: a main body of the construction machinery, consisting of the hydraulic excavator 10; and a remote operating device, disposed at a distance from the hydraulic excavator 10. The remote operating device includes (but not shown) boom remote operating devices, stick remote operating devices, and bucket remote operating devices corresponding to the boom operating device 21, stick operating device 22, and bucket operating device 23 within the cab of the hydraulic excavator 10. If the operator operates the operating levers of the boom remote operating device, stick remote operating device, and bucket remote operating device, the corresponding operating signal is input to the controller 50 of the hydraulic excavator 10 via wireless or wired communication, and the working device 3 performs the action corresponding to the operating signal. In this case, at least one operating device for causing the working device to operate for excavation includes the boom remote operating device, the stick remote operating device, and the bucket remote operating device. Even during excavation operations utilizing this remote operation, the work device control unit outputs a resistance reduction command signal based on the determination result of the contact state determination unit. This signal is used to move the work device in a way that causes the bucket to shift in the resistance reduction direction. Furthermore, machine control as described above can also be performed during this remote operation. In this case, at least one operating device for moving the work device to perform excavation operations can be an operating switch or similar device located remotely and operable by an operator, or it can be any one of the remotely located boom operating device, stick operating device, and bucket operating device.

[0117] In the remote operation described above, the operator watches a monitor while operating the hydraulic excavator 10 from a distance. Therefore, the operator sometimes has difficulty grasping the actual site conditions in detail, and thus may not be able to perform efficient excavation work. Even in this situation, the operating device control unit performs control such as outputting a resistance reduction command signal based on the determination result of the contact state determination unit. This allows the bucket 6 to move in a way that matches the actual site conditions, thereby enabling efficient excavation work.

[0118] (3) Regarding autonomous driving

[0119] In the case of automatic driving, at least one operating device for causing the working device to move to perform digging operations can be, for example, an information terminal that can be input by the operator. This automatic driving refers to the controller 50 automatically controlling the movement of the working device 3 in a manner that causes the bucket 6 to move along a target path of the bucket 6 in the digging operation pre-stored in the controller 50's memory. Such an information terminal can be, for example, a personal computer, a mobile information terminal such as a tablet computer, or other information terminals. If the operator inputs an operation into the information terminal, the terminal outputs a start command to cause the controller 50 to begin automatic driving of the hydraulic excavator 10. The output start command is input to the controller 50 via wireless or wired communication. The operator can input the information terminal outside the hydraulic excavator 10 or inside the cab of the hydraulic excavator 10. In digging operations utilizing this automatic driving (e.g., fully automatic driving), the working device control unit also outputs a resistance reduction command signal based on the determination result of the contact state determination unit, causing the working device to move in a manner that causes the bucket to move in the resistance reduction direction.

[0120] The following is a more detailed explanation of the automatic driving system. In this automatic driving system, the controller 50 determines, for example, whether the bucket teeth of the bucket 6 have reached the digging start position. If the bucket teeth are detected to have reached the digging start position, the controller 50 begins the digging operation. During this digging operation, although the working device control unit outputs a command signal corresponding to the target path, i.e., a target-corresponding command signal, to control the operation of the working device 3, for example, if the contact state determination unit 53 determines that sand is in contact with a specific upper area 64 of the bucket 6, the working device control unit outputs a resistance reduction command signal (a modified version of the target-corresponding command signal) to cause the working device to operate by displacing the bucket in the resistance reduction direction.

[0121] Actual site conditions include various situations that personnel cannot grasp before the operation. Therefore, in the aforementioned automatic driving, if the controller 50 automatically controls the operation of the working device 3 by moving the bucket 6 along a pre-stored target path for the bucket 6 in the digging operation, it may not be possible to perform efficient digging operations. Even in this case, if the working device control unit performs control such as outputting a resistance reduction command signal based on the determination result of the contact state determination unit, the bucket 6 can be moved in a way that matches the actual site conditions, thereby enabling efficient digging operations.

[0122] (D) Regarding the containment state determination section

[0123] In the described embodiment, the containment state determination unit is a contact state determination unit 53 that determines the contact state between a specific upper region 64 and the sand. The operating device control unit outputs the resistance reduction command signal based on the determination result of the contact state determination unit 53. However, the containment state determination unit only needs to be able to determine the containment state of the sand contained in the bucket during excavation operations; it does not necessarily need to determine the contact state between the specific upper region 64 and the sand as described in the embodiment. In this case, the operating device control unit outputs the resistance reduction command signal based on the determination result of the containment state determination unit.

[0124] Specifically, the containment state determination unit could be, for example, a sand quantity determination unit that determines whether a predetermined amount of sand is contained in the bucket during excavation operations. In this case, the operating device control unit outputs the resistance reduction command signal based on the determination result of the sand quantity determination unit. The sand quantity determination unit could also determine whether a predetermined amount of sand is contained in the bucket based on a detection signal input to the controller 50 from a sensor that detects the amount of sand (volume or weight) in the bucket. Furthermore, if the sand quantity calculation unit 52 (accumulation state calculation unit) calculates the amount of sand (e.g., volume) in the bucket by comparing the initial image information with the excavation image information, the sand quantity determination unit could also determine whether a predetermined amount of sand is contained in the bucket based on the amount of sand calculated by the sand quantity calculation unit 52.

[0125] As described above, according to the present invention, there is an engineering machine that can suppress the increase of digging resistance during digging operations and suppress the decrease in the efficiency of digging operations.

[0126] The provided construction machinery includes: a body; a working device comprising a boom undulatingly supported on the body, a stick rotatably supported on the boom, and a bucket supported on the stick, the bucket having a base end rotatably mounted on the stick (i.e., a bucket base end) and a distal end opposite the bucket base end (i.e., a bucket distal end), and having an inner surface defining a space for accommodating sand (i.e., a accommodating space); at least one operating device for actuating the working device to perform digging operations, the digging operations being performed as follows: while in a digging posture, maintaining at least a portion including the bucket distal end in contact with the ground... The device is configured to: a state in which the bucket is displaced relative to the land to excavate sand from the land, wherein the excavation posture is such that the base of the bucket is positioned higher than the distal end of the bucket and capable of excavating sand from the land; and a controller, wherein the controller determines the state of the sand contained in the bucket and, based on the determination of the state of the sand, outputs a resistance reduction command signal, the resistance reduction command signal being a command signal for causing the working device to operate by displacing the bucket in a resistance reduction direction, the resistance reduction direction being a direction that reduces the excavation resistance acting on the bucket.

[0127] This construction machinery determines whether to implement digging resistance reduction controls during excavation operations based on the sand content in the bucket. Therefore, it can suppress the increase of digging resistance and the decrease in excavation efficiency. Specifically, if the amount of sand in the bucket increases, the digging resistance tends to increase as well. Thus, there is a high correlation between the sand content in the bucket and the magnitude of digging resistance. Therefore, the sand content in the bucket can serve as an indicator for determining whether to implement digging resistance reduction controls during excavation operations. Based on the sand content in the bucket, this construction machinery determines whether to implement digging resistance reduction controls during excavation operations. Therefore, when the amount of sand in the bucket increases and digging resistance increases, or when there is a tendency for digging resistance to increase, the bucket can be moved in the direction of resistance reduction to decrease digging resistance. Furthermore, even if the digging resistance does not increase, if the amount of sand in the bucket is large, the bucket is moved in the direction of resistance reduction to further reduce digging resistance, thus suppressing the consumption of excess energy. Therefore, it is possible to suppress the increase of excavation resistance during excavation operations and to suppress the decrease in excavation efficiency.

[0128] Ideally, the containment state determination unit is a contact state determination unit that determines the contact state between a specific upper region and the sand. The specific upper region is the upper portion of the inner surface of the bucket in the digging posture. The operating device control unit outputs the resistance reduction command signal based on the determination result of the contact state determination unit. In this structure, the containment state of the sand contained in the bucket is determined by determining the contact state between the specific upper region of the bucket's inner surface and the sand. That is, in this structure, whether to perform control to reduce digging resistance during digging operations is determined based on the contact state between the specific upper region and the sand. This suppresses the increase in digging resistance during digging operations and prevents a decrease in digging efficiency. Specifically, for the upper portion of the inner surface of the bucket in the digging posture, i.e., the specific upper region, it does not contact the sand when the amount of sand in the bucket is small during digging operations, but contacts the sand when the amount of sand in the bucket increases. Furthermore, as mentioned above, if the amount of sand in the bucket increases, the digging resistance during digging operations tends to increase. Therefore, there is a high correlation between the contact state between a specific upper region and the sand and the magnitude of digging resistance during excavation. Thus, the contact state between a specific upper region and the sand can serve as an indicator for determining whether to implement control measures to reduce digging resistance during excavation. This construction machinery determines whether to implement control measures to reduce digging resistance during excavation based on the contact state between a specific upper region and the sand. Therefore, when the amount of sand in the bucket increases, leading to increased digging resistance or a tendency for increased digging resistance, the bucket can be moved in the direction of resistance reduction to decrease digging resistance. Furthermore, even if digging resistance does not increase, if there is a large amount of sand in the bucket, the bucket is moved in the direction of resistance reduction to further reduce digging resistance, thus suppressing the consumption of excess energy. Therefore, it is possible to suppress the increase of digging resistance during excavation and to prevent a decrease in the efficiency of the excavation operation.

[0129] Ideally, when the contact state determination unit determines that the sand is in contact with the specific upper area of ​​the bucket, the working device control unit outputs the resistance reduction command signal. In this structure, when the sand in the bucket is in contact with the specific upper area, the bucket is moved in the resistance reduction direction to reduce digging resistance. Therefore, the amount of sand in the bucket can be adequately ensured during digging operations.

[0130] Ideally, when the contact state determination unit determines that the sand is not in contact with the specific upper area of ​​the bucket, and the amount of sand contained in the bucket's containment space exceeds a predetermined threshold (i.e., a sand quantity threshold), the operating device control unit outputs the resistance reduction command signal. In this structure, during excavation operations, even if the sand in the bucket is not in contact with the specific upper area, if the amount of sand in the bucket exceeds the sand quantity threshold, a resistance reduction command signal is output. Therefore, before the sand in the bucket comes into contact with the specific upper area, causing an increase in excavation resistance, the bucket can be moved in the resistance reduction direction to reduce excavation resistance. This further suppresses the consumption of excess energy.

[0131] For the aforementioned construction machinery, if the contact state determination unit determines that the sand is not in contact with the specific upper area of ​​the bucket, and the reaction force exerted by the bucket on the ground during the excavation operation, i.e., the excavation reaction force, is greater than a predetermined threshold, i.e., the reaction force threshold, the operating device control unit outputs the resistance reduction command signal. Ideally, in this structure, the reaction force threshold is set, for example, to a value that can suppress a significant decrease in the bucket's operating speed due to an increase in the excavation reaction force. If the bucket's operating speed decreases significantly, the efficiency of the excavation operation will decrease. In this structure, even if the sand in the bucket is not in contact with the specific upper area, if the excavation reaction force is greater than the reaction force threshold, the bucket is displaced in the resistance reduction direction to reduce excavation resistance; therefore, the decrease in excavation efficiency can be further suppressed.

[0132] Ideally, the engineering machinery further includes: a working device posture information acquirer, which acquires information related to the posture of the working device, i.e., working device posture information; and a sand information acquirer, which acquires information related to the sand contained in the receiving space of the bucket, i.e., sand information. The controller further includes: a bucket posture calculation unit, which uses the working device posture information to calculate the posture of the bucket, i.e., bucket posture; and a stacking state calculation unit, which uses the bucket posture and the sand information to calculate the stacking state of the sand in the receiving space of the bucket. The contact state determination unit determines the contact state between the specific upper area and the sand based on the stacking state. In this structure, the contact state between the specific upper area and the sand can be determined based on the actual stacking state of the sand inside the bucket.

[0133] The construction machinery may also include a load detector disposed in the specific upper region, capable of detecting the load, i.e., the sand load, borne by the sand contained in the accommodating space of the bucket. The contact state determination unit determines the contact state between the specific upper region and the sand based on the sand load detected by the load detector. In this structure, the contact state between the specific upper region and the sand can be determined based on the sand load detected by the load detector. Therefore, for example, compared to determining the contact state based on image processing data, the increase in the processing load of the controller can be suppressed.

[0134] Ideally, the controller also includes a tilt calculation unit that calculates a tilt index value, which corresponds to the tilt of the specific upper region relative to a predetermined reference plane. If the tilt index value calculated by the tilt calculation unit is greater than a predetermined threshold (tilt threshold), the operating device control unit does not output the resistance reduction command signal. There is a high correlation between the bucket posture during excavation and the magnitude of excavation resistance. Specifically, for example, when the tilt of a specific upper region relative to the horizontal plane (an example of a reference plane) is large, the excavation resistance tends to decrease; conversely, when the tilt of a specific upper region relative to the horizontal plane is small, the excavation resistance tends to increase. Therefore, when the tilt index value is greater than the tilt threshold, there is a high probability that control to reduce excavation resistance is not needed during excavation, and in this case, no resistance reduction command signal is output. This reduces the processing load on the controller.

Claims

1. An engineering machinery, characterized in that... include: Organism; The working device includes a boom that is undulatingly supported on the machine body, a stick that is rotatably supported on the boom, and a bucket supported on the stick. The bucket has a base end that is rotatably mounted on the stick, i.e., the bucket base end, and a distal end that is located on the opposite side of the bucket base end, i.e., the bucket distal end, and has an inner surface that defines a space for accommodating sand, i.e., a accommodating space. At least one operating device is provided for actuating the working device to perform a digging operation, the digging operation being performed as follows: in a digging posture, while maintaining a state in which at least the portion including the distal end of the bucket is in contact with the ground, the bucket is displaced relative to the ground, thereby digging out the sandy soil of the ground, the digging posture being the posture of the bucket in which the base end of the bucket is positioned higher than the distal end of the bucket and is capable of digging out the sandy soil of the ground. as well as Controller, where The controller Determine the containment state of the sand contained in the bucket. Based on the determination of the containment state, a resistance reduction command signal is output. This resistance reduction command signal is used to activate the working device by displacing the bucket in the resistance reduction direction. The resistance reduction direction is the direction that reduces the digging resistance acting on the bucket. The controller determines the contact state between a specific upper region and the sand, wherein the specific upper region is the upper portion of the inner surface of the bucket in the digging posture. The controller outputs a resistance reduction command signal based on the determination result of the contact state.

2. The engineering machinery according to claim 1, characterized in that: The controller outputs a resistance reduction command signal when it determines that sand is in contact with the specific upper area of ​​the bucket.

3. The engineering machinery according to claim 1, characterized in that: The controller outputs the resistance reduction command signal when it determines that the sand is not in contact with the specific upper area of ​​the bucket and the amount of sand contained in the containment space of the bucket is greater than a predetermined threshold, i.e., the sand amount threshold.

4. The engineering machinery according to claim 1, characterized in that: The controller outputs a resistance reduction command signal when it determines that the sand is not in contact with the specific upper area of ​​the bucket, and when the reaction force that the bucket experiences from the ground during the excavation operation, i.e., the excavation reaction force, is greater than a predetermined threshold, i.e., the reaction force threshold.

5. The engineering machinery according to any one of claims 1 to 4, characterized in that... Also includes: A device posture information acquirer acquires information related to the posture of the device, i.e., device posture information. as well as The sand information acquirer acquires information related to the sand contained in the containment space of the bucket, namely, sand information. The controller The posture information of the working device is used to calculate the posture of the bucket, i.e., the bucket posture. Using the bucket posture and the sand information, the accumulation state of the sand in the bucket's accommodating space is calculated. The controller determines the contact state between the specific upper region and the sand based on the accumulation state.

6. The engineering machinery according to any one of claims 1 to 4, characterized in that... Also includes: A load detector, configured in the specific upper region, is capable of detecting the load, i.e., the sand load, borne by the sand contained in the containment space of the bucket. The controller determines the contact state between the specific upper region and the sand based on the sand load detected by the load detector.

7. The engineering machinery according to any one of claims 1 to 4, characterized in that: The controller calculates a tilt index value, which is an index value corresponding to the tilt of the specific upper region relative to a predetermined reference plane. The controller will not output the resistance reduction command signal if the tilt index value is greater than a predetermined threshold, i.e., the tilt threshold.

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