A payload calculation system for a work machine, a work machine, and a method for calculating the payload of a work machine.

Abstract

This invention provides a payload calculation system for work machines, a work machine, and a method for calculating the payload of a work machine that can calculate the payload more accurately. [Solution] The work machine 40 is attached to the slewing body 30 and has a boom 41 and a bucket 43. The controller 10 calculates the final payload value based on the instantaneous carryback value calculated after the load in the bucket 43 has been discharged and loaded onto the loading target 60, and before the lowering operation of the boom 41 during the empty slewing of the slewing body 30 begins.

Description

Technical Field

[0001] The present disclosure relates to a payload calculation system for a work machine, a work machine, and a method for calculating the payload of a work machine.

Background Art

[0002] Techniques for accurately measuring the weight of loads such as minerals and earth and sand loaded onto a dump truck (the object to be loaded) are disclosed, for example, in Japanese Patent Application Laid-Open No. 2002-285589 (Patent Document 1). In Patent Document 1, the difference between the first weight of the transported material calculated when the turning angle is within the dumping range and the second weight of the transported material calculated when the turning angle is within the measurement range outside the dumping range is determined to be the weight of the transported material. Thereby, even when not all of the load in the bucket is loaded onto the dump truck, the weight of the load actually loaded onto the dump truck can be accurately grasped.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even after discharging the load from the bucket, a part of the load may remain in the bucket, and it may not be possible to accurately calculate the weight (payload) of the load transported by the work machine. The weight value of the load remaining in the bucket after discharging the load is hereinafter referred to as the carry-back value.

[0005] An object of the present disclosure is to provide a payload calculation system for a work machine, a work machine, and a method for calculating the payload of a work machine that can calculate the payload more accurately.

Means for Solving the Problems

[0006] Each of the work machine payload calculation systems and work machines in this disclosure comprises a slewing body, a work implement, and a controller. The work implement is attached to the slewing body and has a boom and a bucket. The controller calculates the payload value based on a carryback value calculated after the load in the bucket has been discharged and before the start of the boom lowering operation during an empty slewing of the slewing body.

[0007] The payload calculation method for a work machine in this disclosure is a method for calculating the payload of a work machine having a slewing body and a work machine attached to the slewing body, which includes a boom and a bucket. The payload calculation method for a work machine in this disclosure comprises the steps of determining whether the load in the bucket has been discharged and calculating the payload value based on the carryback value calculated after determining that the load in the bucket has been discharged and before the start of the boom lowering operation during empty slewing of the slewing body. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a payload calculation system for a work machine, a work machine, and a method for calculating the payload of a work machine that can calculate the payload more accurately. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view showing the configuration of a hydraulic excavator as an example of a work machine in one embodiment. [Figure 2] This block diagram shows the schematic configuration of the payload calculation system for the work machine shown in Figure 1. [Figure 3] This is a schematic diagram of a hydraulic circuit when using an electrically operated control device. [Figure 4] This is a schematic diagram of the hydraulic circuit when using a pilot-operated hydraulic control device. [Figure 5] This is a schematic diagram of a work machine used to explain the balance of moments. [Figure 6] This is a flowchart illustrating the operation of excavation and loading using a hydraulic excavator as an example of a work machine in one embodiment. [Figure 7] This is a top view showing the operation of excavation and loading by a hydraulic excavator as an example of a work machine in one embodiment. [Figure 8] Figures 2 to 4 show the functional blocks within the controller. [Figure 9] This is a flowchart illustrating a method for calculating the payload of a work machine in one embodiment. [Figure 10] This figure shows the change in carryback value during unloaded turning. [Modes for carrying out the invention]

[0010] An embodiment of this disclosure will be described below with reference to the drawings. In the following description, the same or corresponding parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated. In the drawings, some configurations may be omitted or simplified for the sake of clarity. It is also intended from the outset that any configuration may be extracted from the embodiment and combined in any way.

[0011] In the following explanation, "up," "down," "front," "rear," "left," and "right" refer to directions relative to the operator seated in the driver's seat inside the cab 31. "Top view" refers to a viewpoint looking down from above at the work machine 50 or the object to be loaded 60.

[0012] <Configuration of the working machine>

[0013] Figure 1 is a schematic side view showing the configuration of a hydraulic excavator as an example of a work machine in one embodiment. As shown in Figure 1, the hydraulic excavator 50 of this embodiment is a large hydraulic excavator. The hydraulic excavator 50 is, for example, a mining hydraulic excavator used in a mine. The hydraulic excavator 50 mainly consists of a traveling body 35, a rotating body 30, and a work machine 40.

[0014] The traveling body 35 has a pair of crawler belts 35a driven by a traveling motor as a drive source. The hydraulic excavator 50 can travel by driving the crawler belts 35a in the traveling body 35. The revolving body 30 is installed so as to be rotatable with respect to the traveling body 35 about a rotation axis RX by a swing motor (not shown). The rotation axis RX is an imaginary straight line that is the center of rotation of the revolving body 30. Each of the traveling motor and the swing motor is, for example, a hydraulic motor that operates by hydraulic pressure. The revolving body 30 has an operator's cab 31. In the internal space of the operator's cab 31, there are arranged a driver's seat for the operator to sit on, working machine levers 17, 18 (Fig. 2) for the operator to operate, operation switches, and the like.

[0015] The working machine 40 is supported on the front side of the revolving body 30. The working machine 40 has, for example, a boom 41, an arm 42, a bucket 43, and the like. The base end portion of the boom 41 is rotatably connected to the revolving body 30 by a boom foot pin 47. The base end portion of the arm 42 is rotatably connected to the tip end portion of the boom 41 by a boom top pin 48. The bucket 43 is rotatably connected to the tip end portion of the arm 42 by an arm top pin 49.

[0016] The working machine 40 further has a boom cylinder 44, an arm cylinder 45, and a bucket cylinder 46. One end of the boom cylinder 44 is connected to the revolving body 30, and the other end is connected to the boom 41. The boom 41 operates with respect to the revolving body 30 by the extension and contraction of the boom cylinder 44. One end of the arm cylinder 45 is connected to the boom 41, and the other end is connected to the arm 42. The arm 42 operates with respect to the boom 41 by the extension and contraction of the arm cylinder 45. One end of the bucket cylinder 46 is connected to the arm 42, and the other end is connected to a bucket link BL. The bucket 43 operates with respect to the arm 42 by the extension and contraction of the bucket cylinder 46. The boom cylinder 44, the arm cylinder 45, and the bucket cylinder 46 are, for example, hydraulic cylinders that operate based on hydraulic oil.

[0017] In the present embodiment, a large hydraulic excavator has been described as an example of the working machine 50. However, the working machine to which the present disclosure is applied is not limited to this, and it may be a small or medium-sized hydraulic excavator, or any other working machine as long as it has a working machine including a boom and a bucket and a revolving body.

[0018] <Schematic Configuration of Payload Calculation System>

[0019] FIG. 2 is a block diagram showing a schematic configuration of a payload calculation system for a working machine shown in FIG. 1. The system in the present embodiment is a payload calculation system for calculating the weight (payload) of the load carried by the working machine 40.

[0020] As shown in FIG. 2, the system in the present embodiment includes a hydraulic excavator 50 (FIG. 1) as an example of a working machine and a controller 10.

[0021] The bucket IMU (Inertial Measurement Unit) 11 is attached to, for example, a bucket link BL that connects the bucket cylinder 46 and the bucket 43. The bucket IMU 11 detects the acceleration of the bucket 43 in the front-rear direction, left-right direction, and up-down direction, and the angular velocity of the bucket 43 around the front-rear direction, left-right direction, and up-down direction. From the detected values of the bucket IMU 11, the angle of the bucket 43 with respect to the arm 42 (bucket angle A3; see FIG. 5) is calculated. The bucket IMU 11 corresponds to a bucket angle sensor that detects information for calculating the rotation angle of the bucket 43 around the arm top pin 49.

[0022] The bucket angle sensor may be attached around the arm top pin 49. The bucket angle sensor may be a potentiometer or a rotary encoder. Further, the bucket angle sensor may calculate the rotation angle of the bucket 43 from the detected value of a bucket cylinder stroke sensor that detects the displacement amount of the cylinder rod with respect to the cylinder in the bucket cylinder 46.

[0023] The arm IMU 12 is attached to the arm 42. The arm IMU 12 detects the acceleration of the arm 42 in the longitudinal, lateral, and vertical directions, as well as the angular velocity of the arm 42 around the longitudinal, lateral, and vertical directions. From the values ​​detected by the arm IMU 12, the angle of the arm 42 relative to the boom 41 (arm angle A2; see Figure 5) is calculated. The arm IMU 12 corresponds to an arm angle sensor that detects information for calculating the rotation angle of the arm 42 around the boom top pin 48.

[0024] The arm angle sensor may be mounted around the boom top pin 48. The arm angle sensor may be a potentiometer or a rotary encoder. Alternatively, the arm angle sensor may calculate the rotation angle of the arm 42 from the detected value of an arm cylinder stroke sensor that detects the displacement of the cylinder rod relative to the cylinder in the arm cylinder 45.

[0025] The boom IMU 13 is attached to the boom 41. The boom IMU 13 detects the acceleration of the boom 41 in the longitudinal, lateral, and vertical directions, as well as the angular velocity of the boom 41 when it is moved in the longitudinal, lateral, and vertical directions. From the values ​​detected by the boom IMU 13, the angle of the boom 41 relative to the slewing body 30 (boom angle A1; see Figure 5) is calculated. The boom IMU 13 corresponds to a boom angle sensor that detects information for calculating the rotation angle of the boom 41 around the boom foot pin 47.

[0026] The boom angle sensor may be mounted around the boom foot pin 47. The boom angle sensor may be a potentiometer or a rotary encoder. The boom angle sensor may also calculate the rotation angle of the boom 41 from the detected value of a boom cylinder stroke sensor that detects the displacement of the cylinder rod relative to the cylinder in the boom cylinder 44. The bucket angle sensor, arm angle sensor, and boom angle sensor described above correspond to angle sensors that detect information for calculating the rotation angle of the work machine 40.

[0027] The rotating IMU 14 is attached to the rotating body 30. The rotating IMU 14 measures the acceleration of the rotating body 30 in the longitudinal, lateral, and vertical directions, as well as the angular velocity of the rotating body 30 around the longitudinal, lateral, and vertical directions. Each of the IMUs 11 to 14 corresponds to an example of an acceleration sensor in this disclosure. Note that the acceleration sensor in this disclosure is not limited to an IMU, but any sensor capable of detecting acceleration is acceptable.

[0028] The boom cylinder bottom pressure sensor 15 is mounted on the bottom side of the boom cylinder 44 and detects the pressure of the hydraulic fluid in the cylinder bottom side oil chamber of the boom cylinder 44 (bottom pressure). The boom cylinder head pressure sensor 16 is mounted on the head side of the boom cylinder 44 and detects the pressure of the hydraulic fluid in the cylinder head side oil chamber of the boom cylinder 44 (head pressure). Each of the boom cylinder bottom pressure sensor 15 and the boom cylinder head pressure sensor 16 corresponds to an example of a pressure sensor of this disclosure.

[0029] The left work implement lever 17 and the right work implement lever 18 are located inside the operator's cab 31. The left work implement lever 17 and the right work implement lever 18 are operated by an operator sitting in the operator's cab 31. The left work implement lever 17 and the right work implement lever 18 are operated for the operation of the work implement 40 and the slewing body 30. The left work implement lever 17 and the right work implement lever 18 are, for example, electrically operated levers. The left work implement lever 17 and the right work implement lever 18 may also be pilot hydraulic operated levers.

[0030] The left work implement lever 17 is located to the left of the driver's seat. The operator, seated in the driver's seat, grasps the left work implement lever 17 with their left hand and operates it. The left work implement lever 17 controls, for example, the arm 42 and the slewing body 30. The left work implement lever 17 receives input from the operator regarding the rotation direction of the slewing body 30 and the vertical movement of the arm 42. Left-right operation of the left work implement lever 17 corresponds to the rotation of the slewing body 30, and left and right rotation movements of the slewing body 30 are performed according to the left-right operation. Forward-backward operation of the left work implement lever 17 corresponds to the movement of the arm 42, and forward-backward operation is performed according to the movement of the arm 42 in the digging direction and the dumping direction.

[0031] The right work equipment lever 18 is located to the right of the driver's seat. The operator, seated in the driver's seat, grasps the right work equipment lever 18 with their right hand and operates it. The right work equipment lever 18 controls, for example, the boom 41 and the bucket 43. The right work equipment lever 18 receives input from the operator regarding the vertical movement of the boom 41 and the vertical movement of the bucket 43. Forward and backward movement of the right work equipment lever 18 corresponds to the movement of the boom 41, and in response to forward and backward movement, the boom 41 is raised (boom raising movement) and lowered (boom lowering movement). Left and right movement of the right work equipment lever 18 corresponds to the movement of the bucket 43, and in response to left and right movement, the bucket 43 is moved in the digging direction and in the dumping direction.

[0032] The above operating patterns for the left workpiece lever 17 and the right workpiece lever 18 are examples only and are not limited thereto. The forward / backward and left / right operations of the left workpiece lever 17 and the right workpiece lever 18 may correspond to different operations than those described above. Each of the left workpiece lever 17 and the right workpiece lever 18 corresponds to an example of the “operating device” of this disclosure.

[0033] The detection signals from IMUs 11 to 14 are input to the controller 10. The detection signals from the boom cylinder bottom pressure sensor 15 and the boom cylinder head pressure sensor 16 are also input to the controller 10. The detection signals indicating the amount of operation of the work equipment levers 17 and 18 are input to the controller 10.

[0034] The controller 10 includes a processor, main memory, and storage. The processor is, for example, a CPU (Central Processing Unit). The main memory includes non-volatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory). The controller 10 reads a program stored in storage, loads it into main memory, and executes predetermined processing according to the program. The program may also be distributed to the controller 10 via a network.

[0035] The controller 10 and the work levers 17 and 18 may be mounted on the hydraulic excavator 50, or they may be located separately outside the hydraulic excavator 50. If the controller 10 and the work levers 17 and 18 are located separately outside the hydraulic excavator 50, the controller 10 and the work levers 17 and 18 may be wirelessly connected to IMUs 11-14, boom cylinder bottom pressure sensor 15, boom cylinder head pressure sensor 16, etc. The controller 10 may be stored on a server located away from the hydraulic excavator 50. Furthermore, because the work levers 17 and 18 are located away from the hydraulic excavator 50, the operator may operate the hydraulic excavator 50 remotely without boarding the cab 51 of the hydraulic excavator 50.

[0036] Figure 3 is a schematic diagram of the hydraulic circuit when using an electrically operated control device. As shown in Figure 3, the control devices 17 and 18 are electrically operated levers. Therefore, the operator's operation amount on the control devices 17 and 18 is output to the controller 10 as an electrical signal. The operator's operating direction and amount on the control devices 17 and 18 are detected, for example, by a potentiometer. A potentiometer is a displacement sensor that obtains an electrical (voltage) output proportional to the mechanical position. The operation amount of the control devices 17 and 18 detected by the potentiometer is output to the controller 10 as an electrical signal. Note that the control devices 17 and 18 include the left work implement lever 17 and the right work implement lever 18 (Figure 2).

[0037] The controller 10 can determine the operation content of the operating devices 17 and 18 based on the operation signals output from the potentiometer. Based on the operation signals, the controller 10 outputs a command signal (command current) to the main valve (directional control valve) 22. The command signal output from the controller 10 moves the spool of the main valve 22.

[0038] The main valve 22 is a spool-type valve that switches the direction of hydraulic fluid flow by moving, for example, a rod-shaped spool. The amount of hydraulic fluid supplied to the hydraulic actuator 21 is adjusted by the axial movement of the spool. The spool moves axially due to the action of a solenoid based on a command current from the controller 10.

[0039] The hydraulic pump 24 is driven by the rotational force transmitted from an engine (not shown). The hydraulic pump 24 is a variable displacement hydraulic pump that has, for example, a swash plate, and the discharge volume is changed by changing the tilt angle of the swash plate. The oil discharged from the hydraulic pump 24 is supplied to the main valve 22 as hydraulic fluid.

[0040] By moving the spool of the main valve 22 based on the command current, the flow rate and direction of flow (supply and discharge) of the hydraulic fluid supplied from the hydraulic pump 24 to the hydraulic actuator 21 through the main valve 22 are controlled. By controlling the supply and discharge of hydraulic fluid to the hydraulic actuator 21, the operation of the work equipment 40, the rotation of the slewing body 30, and the travel operation of the traveling body 35 are controlled. The hydraulic actuator 21 includes the boom cylinder 44, arm cylinder 45, bucket cylinder 46, slewing motor, travel motor, etc., as shown in Figure 1.

[0041] A monitor 23 is connected to the controller 10. The monitor 23 displays various information acquired by the controller 10. The display contents of the monitor 23 may include, for example, the provisional payload value, the final payload value, the instantaneous carryback value, and the average carryback value calculated by the controller 10. The provisional payload value, final payload value, instantaneous carryback value, and average carryback value will be described later.

[0042] The above description explains the case where the operating devices 17 and 18 are electrically operated, but the operating devices 17 and 18 may also be pilot-hydraulic. Figure 4 is a schematic diagram of the hydraulic circuit when pilot-hydraulic operating devices are used. As shown in Figure 4, the operating devices 17 and 18 are pilot-hydraulic. Therefore, the operator's input to the operating devices 17 and 18 is output to the main valve 22 as pilot hydraulic pressure.

[0043] Pilot oil is supplied from the hydraulic pump 24 to the operating devices 17 and 18 through the solenoid valve 27, and the pressure (pilot hydraulic pressure) is adjusted based on the amount of operation of the operating devices 17 and 18. The pressure-adjusted pilot oil moves the spool of the main valve 22 according to the hydraulic pressure. The movement of the spool adjusts the flow rate and direction of the hydraulic fluid supplied from the hydraulic pump 24 to the hydraulic actuator 21 through the main valve 22. This causes the hydraulic actuator 21 to operate. The opening and closing of the solenoid valve 27 is controlled based on a command (for example, a command current) from the controller 10.

[0044] A pressure sensor 25 is connected to the pilot oil passage 26 that connects the operating devices 17 and 18 to the main valve 22. The pressure sensor 25 detects the pilot oil pressure and outputs it to the controller 10 as an operation signal. The controller 10 can determine the operation content of the operating devices 17 and 18 based on the operation signal output from the pressure sensor 25. A pressure switch may be used instead of the pressure sensor 25 to detect the pilot oil pressure.

[0045] A portion of the oil discharged from the hydraulic pump 24 is reduced to a constant pressure by a pressure reducing valve and used as pilot oil. Another portion of the oil discharged from the hydraulic pump 24 is supplied to the main valve 22 as hydraulic fluid.

[0046] The hydraulic pump 24 may supply both hydraulic fluid and pilot oil as described above. The hydraulic pump 24 may also have a separate hydraulic pump for supplying hydraulic fluid (main hydraulic pump) and a hydraulic pump for supplying pilot oil (pilot hydraulic pump).

[0047] Note that the configuration of the pilot hydraulic system other than those described above is almost the same as that of the electrical system (Figure 3), so the same reference numerals are used for the same elements and their explanations are not repeated.

[0048] In this example, the oil supplied to the hydraulic actuator 21 to operate it is called the hydraulic fluid. The oil supplied to the main valve 22 to operate its spool is called the pilot oil. The pressure of the pilot oil is called the pilot hydraulic pressure.

[0049] <How to calculate the payload>

[0050] The method for calculating the weight (payload) of the load transported by the work machine 40 will be explained. Figure 5 is a schematic diagram of the work machine to illustrate the balance of moments. As shown in Figure 5, in this embodiment, the current weight value W of the load in the bucket 43 is detected from the balance of each moment around the boom foot pin 47. Here, the balance of each moment around the boom foot pin 47 is expressed by the following equation (1).

number

[0051] In equation (1), Mboomcyl is the moment around the boom foot pin 47 caused by the pressure of the hydraulic fluid supplied to the boom cylinder 44. Mboom is the moment around the boom foot pin 47 due to the weight of the boom 41. Marm is the moment around the boom foot pin 47 due to the weight of the arm 42. Mbucket is the moment around the boom foot pin 47 due to the weight of the bucket 43. W is the current weight of the load in the bucket 43. L is the horizontal distance from the boom foot pin 47 to the center of gravity C4 of the load in the bucket 43. Here, the center of gravity C4 of the load is stored in the memory 10a of the controller 10, which is the center of gravity of the load when the bucket 43 is loaded with a load of the rated load. W × L is the moment around the boom foot pin 47 due to the load in the bucket 43.

[0052] Mboomcyl is calculated from the load on the boom cylinder 44 (head pressure and bottom pressure, i.e., the pressure of the hydraulic fluid supplied to the boom cylinder 44). The boom cylinder head pressure sensor 16 detects the head pressure of the boom cylinder 44. The boom cylinder bottom pressure sensor 15 detects the bottom pressure of the boom cylinder 44. Based on the head pressure and bottom pressure of the boom cylinder 44, the controller 10 calculates the moment Mboomcyl around the boom foot pin 47 caused by the load on the boom cylinder 44.

[0053] The Mboom is calculated by the product (r1 × M1) of the distance r1 between the center of gravity C1 of the boom 41 and the boom foot pin 47 and the weight M1 of the boom 41. The position of the center of gravity C1 of the boom 41 is calculated from the boom angle A1, etc. The weight M1 of the boom 41, etc., is stored in the memory 10a of the controller 10.

[0054] Marm is calculated by the product (r2 × M2) of the distance r2 between the center of gravity C2 of arm 42 and the boom foot pin 47 and the weight M2 of arm 42. The position of the center of gravity C2 of arm 42 is calculated from the arm angle A2, etc. The weight M2 of arm 42, etc., is stored in the memory 10a of controller 10.

[0055] The Mbucket is calculated by the product (r3 × M3) of the distance r3 between the center of gravity C3 of the bucket 43 and the boom foot pin 47 and the weight M3 of the bucket 43. The position of the center of gravity C3 of the bucket 43 is calculated from the bucket angle A3, etc. The weight M3 of the bucket 43, etc., is stored in the memory 10a of the controller 10.

[0056] In calculating the current weight W in the bucket 43, the controller 10 calculates the boom angle A1, arm angle A2, and bucket angle A3 based on the detected values ​​of the bucket IMU 11, arm IMU 12, and boom IMU 13, respectively. Based on these boom angles A1, arm angles A2, and bucket angles A3, the controller 10 calculates the positions of the center of gravity C1, C2, C3, and C4. The controller 10 calculates the distances r1, r2, and r3 between the center of gravity C1, C2, and C3 and the boom foot pin 47.

[0057] The controller 10 reads the weight M1 of the boom 41 from memory 10a and calculates the moment Mboom of the boom 41 around the boom foot pin 47 as the product of distance r1 and weight M1. The controller 10 reads the weight M2 of the arm 42 from memory 10a and calculates the moment Marm of the arm 42 around the boom foot pin 47 as the product of distance r2 and weight M2. The controller 10 reads the weight M3 of the bucket 43 from memory 10a and calculates the moment Mbucket of the bucket 43 around the boom foot pin 47 as the product of distance r3 and weight M3.

[0058] The controller 10 reads the length of the boom 41, the length of the arm 42, and the center of gravity C4 of the load in the bucket 43 at the rated load from the memory 10a. Based on the boom angle A1, arm angle A2, and bucket angle A3 calculated above, the lengths of the boom 41 and arm 42, and the center of gravity C4 of the load, the controller 10 calculates the horizontal distance L from the boom foot pin 47 to the center of gravity C4 of the load.

[0059] The controller 10 substitutes the moments Mboomcyl, Mboom, Marm, Mbucket and distance L calculated above into equation (1). This allows the controller 10 to calculate the current load weight W in the bucket 43. The load weight W in the bucket 43 is calculated based on the load on the boom cylinder 44 and the posture of the work machine 40.

[0060] <Payload calculation system and payload calculation method for industrial machinery>

[0061] The payload calculation system and payload calculation method for the work machine in this embodiment, using the above calculation of load weight value W (payload value), will be explained with reference to Figures 6 to 9.

[0062] Figures 6 and 7 are flowcharts and top views, respectively, illustrating the operation of an excavation and loading mechanism using a hydraulic excavator as an example of a work machine. Figure 8 is a diagram showing the functional blocks within the controller shown in Figures 2 to 4. Figure 9 is a flowchart illustrating a method for calculating the payload of a work machine in one embodiment.

[0063] As shown in Figures 6 and 7, in excavation and loading by the work machine 50, excavation is performed first (Step SA: Figure 6). This excavation loads soil and other materials into the bucket 43. After excavation, the slewing body 30 rotates with the load in the bucket 43 (Step SB: Figure 6). This rotation is a so-called load rotation (hoist rotation). This load rotation moves the bucket 43 loaded with the load to directly above the loading target 60. When the bucket 43 reaches the point where the load in the bucket 43 is discharged into the vessel 61, the rotation of the slewing body 30 stops. The loading target 60 is, for example, a dump truck. The dump truck has a vessel 61 for loading the load from the bucket 43.

[0064] After this, the load in bucket 43 is discharged (soil removed) into vessel 61 (Step SC: Figure 6). After soil removal, the slewing body 30 performs an empty slewing (return slewing) in order to excavate again (Step SD: Figure 6). An empty slewing is when the load in bucket 43 is discharged and the slewing body 30 rotates with the bucket 43 empty.

[0065] In this unloaded slewing operation, the slewing motion is performed first, followed by the motion of lowering the boom 41 while slewing. This is because if the motion of lowering the boom 41 while slewing is performed during an unloaded slewing operation immediately after soil removal, there is a risk that the work equipment 40 (for example, the bucket 43) may interfere with the loading object 60 (for example, the side panel 61a of the vessel 61).

[0066] Incidentally, depending on the weather and soil type during operation, soil and other debris may stick to the bucket 43. This stuck soil and debris remains in the bucket 43 even after the load inside has been discharged. This soil and debris stuck to the bucket 43, as well as any other soil, stones, and other debris remaining in the bucket 43, are called carry bags.

[0067] The carry bag is a factor that degrades the accuracy of the load weight value W (hereinafter also referred to as the "payload value") calculated as described above. Therefore, in this embodiment, the payload value can be calculated with high accuracy by accurately calculating the weight value of the carry bag (carry bag value).

[0068] In this embodiment, the carryback value is calculated during the standalone rotation operation in an unloaded rotation. However, the timing of the calculation of the carryback value is not limited to the standalone rotation operation in an unloaded rotation, but may also occur during the operation in an unloaded rotation when the rotating body 30 rotates and the boom 41 is raised. In this embodiment, it is sufficient for the carryback value to be calculated before the lowering operation of the boom 41 in an unloaded rotation begins.

[0069] In this embodiment, the confirmed payload value is calculated by subtracting the carryback value calculated as described above from the provisionally determined provisional payload value. This makes it possible to calculate the weight of the load discharged from the bucket 43 during soil removal (confirmed payload value). Furthermore, since the carryback value is calculated before the lowering operation of the boom 41 begins during empty slewing, an accurate carryback value can be obtained. This makes it possible to calculate the confirmed payload value more accurately. The above will be explained below.

[0070] As shown in Figure 8, the controller 10 that performs the calculation of the payload in this embodiment includes a memory 10a, an acquisition unit 10b, a command signal generation unit 10c, a determination unit 10d, a carryback value calculation unit 10e, a payload value calculation unit 10f, and a control unit 10g.

[0071] As shown in Figures 8 and 9, the acquisition unit 10b of the controller 10 acquires operation signals from the operating devices 17 and 18, detection signals from the IMUs 11 to 14, and detection signals from the pressure sensors 15 and 16. The operation signals from the operating devices 17 and 18 are, for example, signals detected by a potentiometer if the operating devices 17 and 18 are electrically operated. The operation signals from the operating devices 17 and 18 are, for example, signals detected by a pressure sensor 25 (Figure 4) if the operating devices 17 and 18 are pilot hydraulic.

[0072] The command signal generation unit 10c of the controller 10 generates a command signal based on the operation signals from the operation devices 17 and 18 when the operation devices 17 and 18 are electrically operated. The command signal generation unit 10c outputs the generated command signal to the main valve 22. The command signal output from the command signal generation unit 10c is a command current that moves the spool of the main valve 22.

[0073] As described above, the hydraulic actuator 21 operates due to the movement of the spool of the main valve 22. This causes the work machine 50 to perform excavation, etc. This excavation loads soil and other materials into the bucket 43. After excavation, the slewing body 30 rotates the load with the bucket 43 loaded.

[0074] The payload value calculation unit 10f of the controller 10 calculates the instantaneous payload value based on the signal acquired by the acquisition unit 10b (Step S1: Figure 9). The instantaneous payload value is calculated using the method described with reference to Figure 5. This calculates the instantaneous weight value of the load (such as soil) transported by the work machine 40. The payload value calculation unit 10f may continuously calculate the instantaneous payload value. The carry-back instantaneous value corresponds to an example of the "carry-back value" in this disclosure.

[0075] The payload value calculation unit 10f of the controller 10 determines whether a predetermined time has been reached after excavation (Step S2: Figure 9). The predetermined time is, for example, when the work machine 40 is in a predetermined position, or when a predetermined time has elapsed since excavation. The payload value calculation unit 10f determines whether the work machine 40 is in a predetermined position based on detection signals from IMUs 11-14, etc. The payload value calculation unit 10f also determines whether a predetermined time has elapsed since excavation based on the time measured by the controller 10, etc.

[0076] The payload value calculation unit 10f repeats the calculation of the instantaneous payload value (step S1) until it determines that a predetermined time has been reached (NO in step S2). The payload value calculation unit 10f stores the calculated instantaneous payload value in the memory 10a.

[0077] On the other hand, when the payload value calculation unit 10f determines that a predetermined time has been reached, it provisionally determines the payload value and calculates a provisional payload value (step S2). The provisional payload value is, for example, the average value obtained by averaging multiple instantaneous payload values ​​calculated from excavation to a predetermined time. When calculating the average value of the instantaneous payload values, the payload value calculation unit 10f refers to multiple instantaneous payload values ​​stored in the memory 10a.

[0078] After calculating the provisional payload value, the determination unit 10d determines whether the loading operation (soil removal) of the contents of the bucket 43 onto the loading target 60 has been completed (Step S3: Figure 9). This determination is performed by the determination unit 10d based on the command signal obtained from the command signal generation unit 10c, the operation signals of the operating devices 17 and 18 obtained from the acquisition unit 10b, the detection signals of the IMUs 11 to 14, the detection signals of the pressure sensors 15 and 16, etc.

[0079] If the determination unit 10d determines that the loading operation is not yet complete, step S3 is repeated until the loading operation is completed. On the other hand, if the determination unit 10d determines that the loading operation is complete, the work machine 50 starts, for example, a standalone rotation operation during an empty rotation. During the standalone rotation operation in the empty rotation, the carryback value calculation unit 10e calculates the instantaneous carryback value (step S4: Figure 9). The method for calculating the instantaneous carryback value is the same as the method for calculating the payload value explained in Figure 5, so that explanation will not be repeated. The calculation of the instantaneous carryback value may be performed continuously from the start of the standalone rotation operation in the empty rotation until the boom lowering operation is performed.

[0080] The determination unit 10d determines whether or not the lowering operation of the boom 41 has started during unloaded slewing (Step S5: Figure 9). Based on one or more signals selected from the group consisting of command signals obtained from the command signal generation unit 10c, operation signals from the operating devices 17 and 18 obtained from the acquisition unit 10b, and detection signals from the IMUs 11 to 14, the determination unit 10d determines whether or not the lowering operation of the boom 41 has started.

[0081] Specifically, the determination unit 10d determines that the lowering operation of the boom 41 has started when it recognizes from the command signal generation unit 10c that the command signal generation unit 10c has output a signal to the main valve 22 that commands the lowering operation of the boom 41. The determination unit 10d also determines that the lowering operation of the boom 41 has started when it recognizes from the operation signals of the operation devices 17 and 18 that the operator has operated the operation devices 17 and 18 (for example, the right work equipment lever 18) in the direction of lowering the boom 41. The operation signals of the operation devices 17 and 18 are, for example, signals detected by a potentiometer if the operation devices 17 and 18 are of the electrical type shown in Figure 3, and signals detected by, for example, a pressure sensor 25 if the operation devices 17 and 18 are of the pilot hydraulic type shown in Figure 4. The determination unit 10d also determines that the lowering operation of the boom 41 has started when it recognizes from the detection signals of the IMUs 11 to 14 (for example, the boom IMU 13) that the boom 41 has lowered.

[0082] The command signals obtained from the command signal generation unit 10c correspond to command signals that command the operation of the actuator of this disclosure. The operation signals of the operating devices 17 and 18 correspond to the operation signals of the operating devices of this disclosure. The detection signals of the IMUs 11 to 14 correspond to acceleration signals detected by the acceleration sensors of this disclosure.

[0083] If the determination unit 10d determines that the boom lowering operation has not started during unloaded slewing, the carryback value calculation unit 10e repeats the calculation of the instantaneous carryback value during the calculation period from the start of unloaded slewing until the start of the boom lowering operation (Step S4: Figure 9). The carryback value calculation unit 10e stores the calculated payload instantaneous value in the memory 10a.

[0084] On the other hand, if the determination unit 10d determines that the boom lowering operation has started during unloaded slewing, the carryback value calculation unit 10e determines the average carryback value by averaging the multiple instantaneous carryback values ​​calculated during the above calculation period (Step S6: Figure 9). When calculating the average carryback value, the carryback value calculation unit 10e refers to the multiple instantaneous carryback values ​​stored in the memory 10a.

[0085] The payload value calculation unit 10f calculates the confirmed payload value by subtracting the confirmed carryback average value from the provisional payload value (Step S7: Figure 9). The confirmed payload value corresponds to an example of the "payload value" in this disclosure.

[0086] The payload calculation system in this embodiment is configured as described above, and the payload calculation method is executed.

[0087] As shown in Figure 7, the carryback value calculation unit 10e of the controller 10 may calculate the instantaneous carryback value when the bucket 43 is superimposed on the loading object 60 in a top view (when the bucket 43 is moving within the rotation angle range θ of the work machine 40). The rotation angle range θ is the angle range of the work machine 40 centered on the pivot axis RX in a top view. Whether or not the bucket 43 is located within the rotation angle range θ in a top view may be determined by the carryback value calculation unit 10e based on information detected by an imaging device (e.g., a camera), LiDAR (Light Detection and Ranging), etc.

[0088] Furthermore, in the above embodiment, the instantaneous carryback value corresponding to the carryback value of this disclosure is calculated before the start of the boom lowering operation during unloaded slewing, and the average carryback value is calculated after the boom lowering operation. However, the average carryback value may be calculated before the start of the boom lowering operation. Alternatively, the final payload value may be calculated by subtracting a single instantaneous carryback value calculated before the start of the boom lowering operation during unloaded slewing from the provisional payload value.

[0089] <Effects>

[0090] Next, the effects of this embodiment will be described.

[0091] The inventors investigated the change in carryback value during unloaded slewing after soil removal. The results are shown in Figure 10. As shown in Figure 10, the variation in carryback value was smaller during slewing alone in unloaded slewing than during slewing + boom lowering. This is thought to be because the boom lowering operation is an operation in the direction of the boom 41's own weight falling, and the lowering speed of the boom 41 becomes faster, making the carryback value calculated based on the hydraulic pressure of the boom cylinder 44 more prone to variation. Another factor is thought to be that during unloaded slewing, the stability of the work implement 40 deteriorates as it transitions to a full-reach position in preparation for the next excavation.

[0092] In contrast, in this embodiment, as shown in Figure 8, the carryback value calculation unit 10e of the controller 10 calculates the carryback value after the load in the bucket 43 has been discharged and before the lowering operation of the boom 41 during the empty swing of the slewing body 30 begins. Therefore, the variation in the carryback value can be reduced compared to after the lowering operation of the boom 41 has begun. Consequently, it becomes possible to accurately calculate the final payload value, which is calculated by subtracting the carryback value from the provisional payload value.

[0093] Furthermore, in this embodiment, as shown in Figure 8, the determination unit 10d of the controller 10 determines the start of the lowering operation of the boom 41 during unloaded slewing based on one or more signals selected from a group consisting of operation signals from the operating devices 17 and 18, command signals that instruct the operation of the hydraulic actuator 21, and detection signals (acceleration signals) detected by the IMUs 11 to 14. This makes it possible to determine the start of the lowering operation of the boom 41.

[0094] Furthermore, in this embodiment, as shown in Figure 8, the carryback value calculation unit 10e of the controller 10 calculates the carryback value during the calculation period from the start of unloaded slewing to the start of the lowering operation of the boom 41 during unloaded slewing. This makes it possible to obtain a carryback value with little variation and to accurately calculate the fixed payload value.

[0095] Furthermore, in this embodiment, as shown in Figure 8, the carryback value calculation unit 10e of the controller 10 calculates the average value of multiple instantaneous carryback values ​​calculated during the calculation period as the carryback value. This makes it possible to calculate the carryback value with high accuracy.

[0096] When the boom 41 is lowered while the bucket 43 is overlapping the loading object 60 in a top view, there is a high risk that the work equipment 40 will interfere with the loading object 60. For this reason, the lowering operation of the boom 41 is avoided when the bucket 43 is overlapping the loading object 60 in a top view. In this embodiment, as shown in Figures 7 and 8, the carryback value calculation unit 10e of the controller 10 calculates the instantaneous carryback value when the bucket 43 is overlapping the loading area (vessel 61) of the loading object 60 in a top view. This makes it possible to calculate the carryback value with high accuracy while avoiding variations in the carryback value due to the lowering operation of the boom 41.

[0097] Furthermore, in this embodiment, as shown in Figure 8, the carryback value calculation unit 10e of the controller 10 calculates the provisional payload value of the load when it is loaded in the bucket 43, and calculates the final payload value of the load discharged from the bucket by subtracting the carryback value from the provisional payload value. This makes it possible to accurately calculate the final payload value.

[0098] <Note>

[0099] The above description includes the following features.

[0100] (Note 1) A rotating body and A work machine having a boom and a bucket, attached to the aforementioned slewing body, A payload calculation system for a work machine, comprising: a controller that calculates a payload value based on a carryback value calculated after the load in the bucket has been discharged and before the lowering operation of the boom during the empty slewing of the slewing body has started.

[0101] (Note 2) An operating device that receives operation of at least one of the slewing body and the work machine by an operator, An actuator for operating at least one of the slewing body and the work machine, The system further comprises an acceleration sensor for detecting the acceleration of at least one of the rotating body and the work machine, The payload calculation system for the work machine described in Appendix 1, wherein the controller determines the start of the boom lowering operation during the unloaded slewing based on one or more signals selected from a group consisting of an operation signal for the operating device, a command signal for commanding the operation of the actuator, and an acceleration signal detected by the acceleration sensor.

[0102] (Note 3) The controller is a payload calculation system for a work machine as described in Appendix 1 or Appendix 2, which calculates the carryback value during the calculation period from the start of the unloaded slewing to the start of the boom lowering operation during the unloaded slewing.

[0103] (Note 4) The controller calculates a plurality of instantaneous carryback values ​​as the carryback value calculated during the calculation period, and calculates the average value of the plurality of instantaneous carryback values ​​as the carryback average value, in the payload calculation system for the work machine described in Appendix 3.

[0104] (Note 5) The payload calculation system for the work machine described in Appendix 4, wherein the controller calculates a provisional payload value with a load loaded in the bucket, and calculates the payload value by subtracting the average carry-back value from the provisional payload value.

[0105] (Note 6) The controller is a payload calculation system for a work machine as described in any one of Appendix 1 to Appendix 5, which calculates the carryback value when the bucket is superimposed on the load object in a top view.

[0106] (Note 7) A rotating body and A work machine having a boom and a bucket, attached to the aforementioned slewing body, A work machine comprising: a controller that calculates a payload value based on a carryback value calculated after the load in the bucket has been discharged and before the lowering operation of the boom during the empty slewing of the slewing body has started.

[0107] (Note 8) An operating device that receives operation of at least one of the slewing body and the work machine by an operator, An actuator for operating at least one of the slewing body and the work machine, The system further comprises an acceleration sensor for detecting the acceleration of at least one of the rotating body and the work machine, The working machine as described in Appendix 7, wherein the controller determines the start of the lowering operation of the boom during the unloaded slewing based on one or more signals selected from a group consisting of an operation signal of the operating device, a command signal that commands the operation of the actuator, and an acceleration signal detected by the acceleration sensor.

[0108] (Note 9) The controller calculates the carryback value during the calculation period from the start of the unloaded slewing to the start of the boom lowering operation during the unloaded slewing, as described in Appendix 7 or Appendix 8 of the working machine.

[0109] (Note 10) The controller calculates a plurality of instantaneous carryback values ​​as the carryback values ​​calculated during the calculation period, and calculates the average value of the plurality of instantaneous carryback values ​​as the average carryback value, as described in Appendix 9.

[0110] (Note 11) The controller calculates a provisional payload value with a load loaded in the bucket, and calculates the payload value by subtracting the average carry-back value from the provisional payload value, as described in Appendix 10.

[0111] (Note 12) The controller is a work machine according to any one of the appendices 7 to 11, which calculates the carryback value when the bucket is superimposed on the object to be loaded in a top view.

[0112] (Note 13) A method for calculating the payload of a work machine having a slewing body and a work machine attached to the slewing body, including a boom and a bucket, A step of determining the discharge of the load in the bucket, A method for calculating the payload of a work machine, comprising the step of calculating a payload value based on a carryback value calculated after determining that the load in the bucket has been discharged and before the start of the lowering operation of the boom during the empty slewing of the slewing body.

[0113] (Note 14) The aforementioned work machine is An operating device that receives operation of at least one of the slewing body and the work machine by an operator, An actuator for operating at least one of the slewing body and the work machine, The system further includes an acceleration sensor that detects the acceleration of at least one of the rotating body and the work machine, A method for calculating the payload of a work machine as described in Appendix 13, which determines the start of the lowering operation of the boom during the unloaded slewing based on one or more signals selected from a group consisting of an operation signal of the operating device, a command signal that commands the operation of the actuator, and an acceleration signal detected by the acceleration sensor.

[0114] (Note 15) The carryback value is calculated during the calculation period from the start of the unloaded slewing to the start of the boom lowering operation during the unloaded slewing, according to the payload calculation method for the work machine described in Appendix 13 or Appendix 14.

[0115] (Note 16) A method for calculating the payload of a work machine as described in Appendix 15, wherein the average value of multiple instantaneous carryback values ​​calculated as the carryback value during the calculation period is calculated as the carryback average value.

[0116] (Note 17) The method for calculating the payload of a work machine as described in Appendix 16, further comprising the steps of calculating a provisional payload value of the load in the state in which the load is loaded in the bucket, and calculating the payload value by subtracting the average value of the carry bag from the provisional payload value.

[0117] (Note 18) A method for calculating the payload of a work machine as described in any one of Appendix 13 to Appendix 17, wherein the carryback value is calculated when the bucket is superimposed on the object to be loaded in a top view.

[0118] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0119] 10 Controller, 10a Memory, 10b Acquisition Unit, 10c Command Signal Generation Unit, 10d Judgment Unit, 10e Carryback Value Calculation Unit, 10f Payload Value Calculation Unit, 10g Control Unit, 12 Arm IMU, 13 Boom IMU, 14 Slewing Body IMU, 15 Boom Cylinder Bottom Pressure Sensor, 16 Boom Cylinder Head Pressure Sensor, 17 Left Work Equipment Lever, 18 Right Work Equipment Lever, 21 Hydraulic Actuator, 22 Main Valve, 23 Monitor, 24 Hydraulic Pump, 25 Pressure Sensor, 26 Pilot Oil Passage, 27 Solenoid Valve, 30 Slewing Body, 31 Cab, 35 Running Body, 35a Tracks, 40 Work Equipment, 41 Boom, 42 Arm, 43 Bucket, 44 Boom Cylinder, 45 Arm Cylinder, 46 Bucket Cylinder, 47 Boom Foot Pin, 48 Boom Top Pin, 49 Arm top pin, 50 working machine, 60 load object, 61 vessel, 61a side panel, BL bucket link.

Claims

1. A rotating body and A work machine having a boom and a bucket, attached to the aforementioned slewing body, A payload calculation system for a work machine, comprising: a controller that calculates a payload value based on a carryback value calculated after the load in the bucket has been discharged and before the lowering operation of the boom in the empty slewing of the slewing body has started.

2. An operating device that receives operation of at least one of the slewing body and the work machine by an operator, An actuator for operating at least one of the slewing body and the work machine, The system further comprises an acceleration sensor for detecting the acceleration of at least one of the rotating body and the work machine, The payload calculation system for a work machine according to claim 1, wherein the controller determines the start of the boom lowering operation during the unloaded slewing based on one or more signals selected from a group consisting of an operation signal for the operating device, a command signal for commanding the operation of the actuator, and an acceleration signal detected by the acceleration sensor.

3. The payload calculation system for a work machine according to claim 1, wherein the controller calculates the carryback value during a calculation period from the start of the unloaded slewing to the start of the boom lowering operation during the unloaded slewing.

4. The payload calculation system for a work machine according to claim 3, wherein the controller calculates a plurality of instantaneous carryback values ​​as the carryback value calculated during the calculation period, and calculates the average value of the plurality of instantaneous carryback values ​​as the average carryback value.

5. The payload calculation system for a work machine according to claim 4, wherein the controller calculates a provisional payload value with a load loaded in the bucket, and calculates the payload value by subtracting the average carry-back value from the provisional payload value.

6. The payload calculation system for a work machine according to claim 1, wherein the controller calculates the carryback value when the bucket is superimposed on the object to be loaded in a top view.

7. A rotating body and A work machine having a boom and a bucket, attached to the aforementioned slewing body, A work machine comprising: a controller that calculates a payload value based on a carryback value calculated after the load in the bucket has been discharged and before the lowering operation of the boom during the empty slewing of the slewing body has started.

8. An operating device that receives operation of at least one of the slewing body and the work machine by an operator, An actuator for operating at least one of the slewing body and the work machine, The system further comprises an acceleration sensor for detecting the acceleration of at least one of the rotating body and the work machine, The working machine according to claim 7, wherein the controller determines the start of the lowering operation of the boom during the unloaded slewing based on one or more signals selected from a group consisting of an operation signal of the operating device, a command signal that commands the operation of the actuator, and an acceleration signal detected by the acceleration sensor.

9. The work machine according to claim 7, wherein the controller calculates the carryback value during the calculation period from the start of the unloaded slewing to the start of the lowering operation of the boom during the unloaded slewing.

10. The work machine according to claim 9, wherein the controller calculates a plurality of instantaneous carryback values ​​as the carryback values ​​calculated during the calculation period, and calculates the average value of the plurality of instantaneous carryback values ​​as the average carryback value.

11. The work machine according to claim 10, wherein the controller calculates a provisional payload value with a load loaded in the bucket, and calculates the payload value by subtracting the average value of the carry bag from the provisional payload value.

12. The work machine according to claim 7, wherein the controller calculates the carryback value when the bucket is superimposed on the object to be loaded in a top view.

13. A method for calculating the payload of a work machine having a slewing body and a work machine attached to the slewing body, including a boom and a bucket, A step of determining the discharge of the load in the bucket, A method for calculating the payload of a work machine, comprising the step of calculating a payload value based on a carryback value calculated after determining that the load in the bucket has been discharged and before the start of the lowering operation of the boom during the empty slewing of the slewing body.

14. The aforementioned work machine is An operating device that receives operation of at least one of the slewing body and the work machine by an operator, An actuator for operating at least one of the slewing body and the work machine, The system further includes an acceleration sensor that detects the acceleration of at least one of the rotating body and the work machine, A method for calculating the payload of a work machine according to claim 13, wherein the start of the lowering operation of the boom during the unloaded slewing is determined based on one or more signals selected from a group consisting of an operation signal of the operating device, a command signal that commands the operation of the actuator, and an acceleration signal detected by the acceleration sensor.

15. The method for calculating the payload of a work machine according to claim 13, wherein the carryback value is calculated during the calculation period from the start of the unloaded slewing to the start of the lowering operation of the boom during the unloaded slewing.

16. A method for calculating the payload of a work machine according to claim 15, wherein the average value of a plurality of instantaneous carryback values ​​calculated as the carryback value during the calculation period is calculated as the carryback average value.

17. A method for calculating the payload of a work machine according to claim 16, further comprising the steps of calculating a provisional payload value of the load in the state in which the load is loaded in the bucket, and calculating the payload value by subtracting the average value of the carry bag from the provisional payload value.

18. The method for calculating the payload of a work machine according to claim 13, wherein the carryback value is calculated when the bucket is superimposed on the object to be loaded in a top view.

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