Working machinery
By incorporating a memory unit to store the center of gravity position, the working machine accurately calculates the weight of lifted objects, addressing the inaccuracy issue in conventional systems.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- SUMITOMO HEAVY IND LTD
- Filing Date
- 2022-06-06
- Publication Date
- 2026-06-23
Smart Images
Figure 0007877622000001 
Figure 0007877622000002 
Figure 0007877622000003
Abstract
Description
Technical Field
[0001] The present invention relates to a working machine.
Background Art
[0002] Conventionally, there has been known a working machine that adsorbs iron filings and the like to a lifting magnet provided at the tip of an attachment, and lifts using the attachment to load onto the loading platform of a dump truck or the like.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the above-described conventional technology, the weight of the lifting magnet mounted on the working machine is considered, but the center of gravity of the lifted object is not considered. In a working machine equipped with a lifting magnet, if the weight of the lifted object is calculated without considering the center of gravity of the lifted object, there is a possibility that the calculated weight of the object includes an error based on the deviation of the center of gravity of the object.
[0005] One aspect of the present invention provides a technique for improving the calculation accuracy of the weight of a conveyed object by considering the center of gravity of the conveyed object adsorbed to a lifting magnet.
Means for Solving the Problems
[0006] A working machine according to one aspect of the present invention includes an attachment attached to an upper swing body, a lifting magnet provided at the tip of the attachment, A memory unit that stores the position of the center of gravity of the conveyed object attracted to the lifting magnet, and has In the initial setup process, the position of the center of gravity is calculated from the first transported object that has been attracted to the lifting magnet, and the calculated position of the center of gravity is stored in the memory unit. When a second transported object, different from the first transported object, is attracted to the lifting magnet, the weight of the second transported object is calculated based on the position of the center of gravity stored in the memory unit. .
Effects of the Invention
[0007] According to one aspect of the present invention, the accuracy of calculating the weight of a conveyed object can be improved. [Brief explanation of the drawing]
[0008] [Figure 1] Figure 1 is a side view of a work machine according to an embodiment. [Figure 2] Figure 2 shows an example of the configuration of a drive system mounted on a work machine according to the first embodiment. [Figure 3] Figure 3 is a schematic diagram illustrating the parameters for calculating the weight of the object to be lifted by the attachment of the work machine according to the first embodiment. [Figure 4] Figure 4 illustrates a lifting magnet whose angle is controlled by an angle control unit according to the first embodiment. [Figure 5] Figure 5 is a flowchart showing an example of the initial setup process flow until the work machine according to the first embodiment stores the center of gravity of the conveyed object. [Modes for carrying out the invention]
[0009] Embodiments of the present invention will be described below with reference to the drawings. Furthermore, the embodiments described below are illustrative and not limiting to the invention, and not all features or combinations thereof described in the embodiments are necessarily essential to the invention. In addition, identical or corresponding components in each drawing are denoted by the same or corresponding reference numerals, and their descriptions may be omitted.
[0010] (Overview of the machinery) Figure 1 is a side view of the work machine 100 according to this embodiment. The upper slewing body 3 is mounted on the lower traveling body 1 of the work machine 100 via a slewing mechanism 2. A boom 4 is attached to the upper slewing body 3. An arm 5 is attached to the tip of the boom 4, and a lifting magnet 6, which serves as an end attachment (work tool), is attached to the tip of the arm 5. The boom 4 and arm 5 constitute a work attachment, which is an example of an attachment. The boom 4 is driven by a boom cylinder 7 (an example of a hydraulic cylinder), the arm 5 is driven by an arm cylinder 8 (an example of a hydraulic cylinder), and the lifting magnet 6 is driven by a lifting magnet cylinder 9 (an example of a hydraulic cylinder). In this embodiment, the work tool (transport mechanism) that can be attached to the tip of the attachment and used to transport materials is the lifting magnet 6, but other work tools such as a grapple, demolition fork, or harvester including a chainsaw may be attached depending on the type of work.
[0011] A boom angle sensor S1 is attached to boom 4, an arm angle sensor S2 is attached to arm 5, and a lifting magnet angle sensor S3 is attached to lifting magnet 6. A controller 30, a display device 40, a spatial recognition device 80, a machine tilt sensor S4, and a rotational angular velocity sensor S5 are attached to the upper rotating body 3.
[0012] The boom angle sensor S1 is configured to detect the boom angle, which is the rotation angle of the boom 4 relative to the upper slewing body 3. The boom angle sensor S1 may be, for example, a rotation angle sensor that detects the rotation angle of the boom 4 around the boom foot pin, a cylinder stroke sensor that detects the stroke amount of the boom cylinder 7 (boom stroke amount), or a tilt (acceleration) sensor that detects the tilt angle of the boom 4, or a combination of an acceleration sensor and a gyro sensor. The same applies to the arm angle sensor S2 that detects the arm angle, which is the rotation angle of the arm 5 relative to the boom 4, and the lifting magnet angle sensor S3 that detects the lifting magnet angle, which is the rotation angle of the lifting magnet 6 relative to the arm 5.
[0013] The machine tilt sensor S4 is configured to detect the tilt (machine tilt angle) of the upper rotating body 3 with respect to the horizontal plane. In this embodiment, the machine tilt sensor S4 is an acceleration sensor that detects the tilt angle of the upper rotating body 3 around its longitudinal axis and left-right axis. The longitudinal axis and left-right axis of the upper rotating body 3 are, for example, orthogonal to each other and pass through the machine center point, which is a point on the rotation axis of the work machine 100.
[0014] The rotational angular velocity sensor S5 detects the rotational angular velocity of the upper rotating body 3. In this embodiment, it is a gyro sensor. A resolver, rotary encoder, etc., may also be used.
[0015] The spatial recognition device 80 is configured to image the area around the work machine 100. The spatial recognition device 80 is, for example, a monocular camera, a stereo camera, a depth image camera, an infrared camera, or a LiDAR. In the example in Figure 1, the spatial recognition device 80 includes a front camera 80F mounted on the front end of the upper surface of the upper rotating body 3, a back camera 80B mounted on the rear end of the upper surface of the upper rotating body 3, a left camera 80L mounted on the left end of the upper surface of the upper rotating body 3, and a right camera 80R mounted on the right end of the upper surface of the upper rotating body 3 (invisible in Figure 1).
[0016] The spatial recognition device 80 is, for example, a monocular camera having an imaging element such as a CCD or a CMOS, and outputs the captured image to the display device 40. The spatial recognition device 80 may be configured to calculate the distance to an object recognized from the spatial recognition device 80 or the working machine 100. When not only using the captured image but also using a millimeter-wave radar, an ultrasonic sensor, a laser radar, etc. as the spatial recognition device 80, a large number of signals (such as laser light) are transmitted to the object, and the reflected signal is received, and the distance and direction of the object may be detected from the reflected signal.
[0017] The spatial recognition device 80 is configured to detect an object existing around the working machine 100. The object is, for example, a dump truck, a terrain shape (slope, hole, etc.), an electric wire, a utility pole, a person, an animal, a vehicle, a construction machine, a building, a wall, a helmet, a safety vest, work clothes, or a predetermined mark on the helmet, etc. In this way, the spatial recognition device 80 may be configured to be able to identify at least one of the type, position, and shape of the object. For example, the spatial recognition device 80 may be configured to distinguish between a person and an object other than a person.
[0018] A boom rod pressure sensor S6a, a boom bottom pressure sensor S6b, and a boom cylinder stroke sensor S7 may be attached to the boom cylinder 7. An arm rod pressure sensor S6c, an arm bottom pressure sensor S6d, and an arm cylinder stroke sensor S8 may be attached to the arm cylinder 8. A lifting magnet rod pressure sensor S6e, a lifting magnet bottom pressure sensor S6f, and a lifting magnet cylinder stroke sensor S9 may be attached to the lifting magnet cylinder 9.
[0019] The boom rod pressure sensor S6a detects the pressure in the rod side oil chamber of the boom cylinder 7 (hereinafter referred to as "boom rod pressure"). The boom bottom pressure sensor S6b detects the pressure in the bottom side oil chamber of the boom cylinder 7 (hereinafter referred to as "boom bottom pressure"). The arm rod pressure sensor S6c detects the pressure in the rod side oil chamber of the arm cylinder 8 (hereinafter referred to as "arm rod pressure"). The arm bottom pressure sensor S6d detects the pressure in the bottom side oil chamber of the arm cylinder 8 (hereinafter referred to as "arm bottom pressure"). The lifting magnet rod pressure sensor S6e detects the pressure in the rod side oil chamber of the lifting magnet cylinder 9 (hereinafter referred to as "lifting magnet rod pressure"). The lifting magnet bottom pressure sensor S6f detects the pressure in the bottom side oil chamber of the lifting magnet cylinder 9 (hereinafter referred to as "lifting magnet bottom pressure").
[0020] The upper revolving body 3 is provided with a cab 10 as an operator's cab and is equipped with a power source such as an engine 11.
[0021] Further, on the upper revolving body 3, the cab 10 is provided so as to be able to move up and down via a cab lifting device 90. Hereinafter, such a cab that can move up and down may be referred to as an "elevator cab". Note that FIG. 1 shows a state where the cab 10 has been lifted to the highest position by the cab lifting device 90. Also, the cab 10 is arranged on the side (usually the left side) of the boom 4.
[0022] (First Embodiment) FIG. 2 is a diagram showing a configuration example of a drive system mounted on a working machine 100 according to the first embodiment. In FIG. 2, the mechanical power transmission system is indicated by a double line, the hydraulic oil line is indicated by a thick solid line, the pilot line is indicated by a broken line, the electric control system is indicated by a one-dot chain line, and the electric drive system is indicated by a thick dotted line, respectively.
[0023] The drive system of the working machine 100 mainly includes an engine 11, a main pump 14, a hydraulic pump 14G, a pilot pump 15, a control valve 17, an operating device 26, a controller 30, and an engine control device 74.
[0024] Engine 11 is the power source for the work machine 100 and is, for example, a diesel engine that operates to maintain a predetermined rotational speed. The output shaft of engine 11 is connected to the input shafts of the alternator 11a, the main pump 14, the hydraulic pump 14G, and the pilot pump 15, respectively.
[0025] The main pump 14 supplies hydraulic fluid to the control valve 17 via the hydraulic fluid line 16. In this embodiment, the main pump 14 is a swashplate type variable displacement hydraulic pump.
[0026] The regulator 13 controls the discharge volume of the main pump 14. In this embodiment, the regulator 13 controls the discharge volume of the main pump 14 by adjusting the swash plate tilt angle of the main pump 14 in accordance with control signals from the controller 30, etc.
[0027] The pilot pump 15 supplies hydraulic fluid to various hydraulic control devices, including the operating device 26, via the pilot line 25. In this embodiment, the pilot pump 15 is a fixed-displacement hydraulic pump.
[0028] The control valve 17 is a hydraulic control device that controls the hydraulic system in the work machine 100. The control valve 17 selectively supplies the hydraulic fluid discharged by the main pump 14 to one or more of the following: the boom cylinder 7, the arm cylinder 8, the lifting magnet cylinder 9, the left-side travel hydraulic motor 1L, the right-side travel hydraulic motor 1R, and the slewing hydraulic motor 2A. In the following description, the boom cylinder 7, the arm cylinder 8, the lifting magnet cylinder 9, the left-side travel hydraulic motor 1L, the right-side travel hydraulic motor 1R, and the slewing hydraulic motor 2A are collectively referred to as "hydraulic actuators."
[0029] The operating device 26 is a device used by the operator to operate the hydraulic actuator. In this embodiment, the operating device 26 generates pilot pressure by supplying hydraulic fluid from the pilot pump 15 to the pilot port of the corresponding flow control valve located in the control valve 17. Specifically, the operating device 26 includes a left operating lever for slewing and arm operation, a right operating lever for boom operation and lifting magnet operation, a travel pedal, and a travel lever (none of which are shown). The pilot pressure changes according to the operation of the operating device 26 (including, for example, the direction and amount of operation).
[0030] The operating pressure sensor 29 detects the pilot pressure generated by the operating device 26. In this embodiment, the operating pressure sensor 29 detects the pilot pressure generated by the operating device 26 and outputs the detected value to the controller 30. The controller 30 understands the operation of each operating device 26 based on the output of the operating pressure sensor 29.
[0031] The controller 30 is a control device that performs various calculations. In this embodiment, the controller 30 is a microcomputer equipped with a CPU, a volatile memory device, a non-volatile memory device, and the like. For example, the controller 30 reads programs corresponding to various functions from the non-volatile memory device and loads them into the volatile memory device, and causes the CPU to execute the processing corresponding to each of those programs.
[0032] The hydraulic pump 14G supplies hydraulic fluid to the hydraulic motor 60 via the hydraulic fluid line 16. In this embodiment, the hydraulic pump 14G is a fixed-displacement hydraulic pump and supplies hydraulic fluid to the hydraulic motor 60 through the switching valve 61.
[0033] The switching valve 61 is configured to switch the flow of hydraulic fluid discharged by the hydraulic pump 14G. In this embodiment, the switching valve 61 is a solenoid valve whose valve position is switched in response to a control command from the controller 30. The switching valve 61 has a first valve position that connects the hydraulic pump 14G and the hydraulic motor 60, and a second valve position that blocks the connection between the hydraulic pump 14G and the hydraulic motor 60.
[0034] When the mode selector switch 62 is operated and the operating mode of the work machine 100 is switched to the lifting magnet mode, the controller 30 outputs a control signal to the selector valve 61 to switch the selector valve 61 to the first valve position. Also, when the mode selector switch 62 is operated and the operating mode of the work machine 100 is switched to a mode other than the lifting magnet mode, the controller 30 outputs a control signal to the selector valve 61 to switch the selector valve 61 to the second valve position. Figure 2 shows the state when the selector valve 61 is in the second valve position.
[0035] The mode selector switch 62 is a switch that switches the operating mode of the work machine 100. In this embodiment, it is a rocker switch installed inside the cab 10. The operator switches between shovel mode and lifting magnet mode either way by operating the mode selector switch 62. Shovel mode is the operating mode when the work machine 100 is operated as an excavator (shovel), and is selected, for example, when a bucket is attached to the tip of the arm 5 instead of the lifting magnet 6. Lifting magnet mode is the mode when the work machine 100 is operated as a work machine with a lifting magnet, and is selected when the lifting magnet 6 is attached to the tip of the arm 5. The controller 30 may also automatically switch the operating mode of the work machine 100 based on the output of various sensors.
[0036] When the lifting magnet mode is selected, the switching valve 61 is set to the first valve position, allowing the hydraulic fluid discharged by the hydraulic pump 14G to flow into the hydraulic motor 60. On the other hand, when an operating mode other than the lifting magnet mode is selected, the switching valve 61 is set to the second valve position, allowing the hydraulic fluid discharged by the hydraulic pump 14G to flow into the hydraulic fluid tank without flowing into the hydraulic motor 60.
[0037] The rotating shaft of the hydraulic motor 60 is mechanically connected to the rotating shaft of the generator 63. The generator 63 generates power to excite the lifting magnet 6. In this embodiment, the generator 63 is an AC generator that operates in response to control commands from the power control device 64.
[0038] The power control device 64 controls the supply and interruption of power to excite the lifting magnet 6. In this embodiment, the power control device 64 controls the start and stop of AC power generation by the generator 63 in response to power generation start commands and power generation stop commands from the controller 30. The power control device 64 also converts the AC power generated by the generator 63 into DC power and supplies it to the lifting magnet 6. Furthermore, the power control device 64 can control the magnitude of the voltage applied to the lifting magnet 6 and the magnitude of the current flowing through the lifting magnet 6.
[0039] When the lifting magnet switch 65 is turned on, the controller 30 outputs an attraction command to the power control device 64. Upon receiving the attraction command, the power control device 64 converts the AC power generated by the generator 63 into DC power and supplies it to the lifting magnet 6, thereby exciting the lifting magnet 6. The excited lifting magnet 6 becomes capable of attracting an object (magnetic material).
[0040] Furthermore, when the lifting magnet switch 65 is turned off, the controller 30 outputs a release command to the power control device 64. Upon receiving the release command, the power control device 64 stops power generation by the generator 63 and returns the lifting magnet 6, which is in the attached state, to the detached state (released state). The released state of the lifting magnet 6 means that the power supply to the lifting magnet 6 has been stopped and the electromagnetic force generated by the lifting magnet 6 has disappeared.
[0041] The lifting magnet switch 65 is a switch that switches between attracting and releasing the lifting magnet 6. In this embodiment, the lifting magnet switch 65 includes a weak excitation button 65A and a strong excitation button 65B, which are push-button switches provided on the top of the left operating lever 26L, and a release button 65C, which is a push-button switch provided on the top of the right operating lever 26R.
[0042] The weak excitation button 65A is an example of an input device for applying a predetermined voltage to the lifting magnet 6 to put the lifting magnet 6 into an attracted state (weak attracted state). The predetermined voltage is, for example, a voltage set via the magnetic force adjustment dial 66.
[0043] The strong excitation button 65B is an example of an input device for applying the maximum allowable voltage to the lifting magnet 6 to put the lifting magnet 6 into an attracted state (strong attracted state).
[0044] The release button 65C is an example of an input device for releasing the lifting magnet 6.
[0045] The magnetic force adjustment dial 66 is a dial for adjusting the magnetic force (attractive force) of the lifting magnet 6. In this embodiment, the magnetic force adjustment dial 66 is installed inside the cab 10 and is configured to switch the magnetic force (attractive force) of the lifting magnet 6 in four stages when the weak excitation button 65A is pressed. Specifically, the magnetic force adjustment dial 66 is configured to switch the magnetic force (attractive force) of the lifting magnet 6 in four stages, from the first level to the fourth level. Figure 2 shows the state in which the third level is selected on the magnetic force adjustment dial 66.
[0046] The lifting magnet 6 is controlled to generate a magnetic force (attraction force) at a level set by the magnetic force adjustment dial 66. The magnetic force adjustment dial 66 outputs data indicating the level of magnetic force (attraction force) to the controller 30.
[0047] This configuration allows the operator to operate the work attachment by operating the left control lever 26L with their left hand and the right control lever 26R with their right hand, while simultaneously using their fingers to attract and release objects (magnetic materials) using the lifting magnet 6. Typically, the operator presses the weak excitation button 65A while the lifting magnet 6 is in contact with an object (e.g., scrap metal) to attract the scrap metal to the lifting magnet 6. Then, the operator slowly raises the boom 4, lifting the lifting magnet 6 with the scrap metal attracted, and then presses the strong excitation button 65B to increase the magnetic force (attractive force) of the lifting magnet 6. This is to prevent the scrap metal from falling off the lifting magnet 6 during attachment operation (including at least one of boom operation, arm operation, and bucket operation) or slewing operation.
[0048] Furthermore, the operator can sort objects by adjusting the magnetic force (attraction force) of the lifting magnet 6 using the magnetic force adjustment dial 66. For example, the operator can use a relatively weak level of magnetic force (attraction force) to selectively lift and move relatively light objects from a pile of scrap, thereby separating relatively light objects from relatively heavy objects. This is because using a relatively weak level of magnetic force (attraction force) prevents the operator from accidentally lifting relatively heavy objects.
[0049] The work machine 100 may be configured to automatically switch the operating mode to a speed limit mode when the weak excitation button 65A or the strong excitation button 65B is pressed. The speed limit mode is an operating mode in which, for example, in the lifting magnet mode, the slewing speed and the drive speed of the attachment are limited.
[0050] Furthermore, if a predetermined operation is performed or a predetermined state is reached after the weak excitation button 65A is pressed, the work machine 100 may automatically switch the state of the lifting magnet 6 to the strong attraction state, which is the state when the strong excitation button 65B is pressed. The predetermined operation is, for example, a slewing operation. The predetermined state is, for example, a state in which the attachment is in a predetermined posture, specifically, a state in which the boom angle is at a predetermined angle. In this case, for example, if the lifting magnet 6, which is in the weak attraction state after the weak excitation button 65A is pressed, is lifted in response to a boom raising operation and then a slewing operation is performed, the work machine 100 can automatically switch the state of the lifting magnet 6 to the strong attraction state even if the strong excitation button 65B is not pressed.
[0051] The display device 40 is a device that displays various information. In this embodiment, the display device 40 is fixed to the right front pillar (not shown) of the cab 10 where the driver's seat is located. As shown in Figure 2, the display device 40 can provide information to the operator by displaying information related to the work machine 100 on the image display unit 41. The display device 40 also includes a switch panel 42 as an input device. The operator can input various commands to the controller 30 using the switch panel 42.
[0052] The switch panel 42 is a panel that includes various switches. In this embodiment, the switch panel 42 includes a light switch 42a, a wiper switch 42b, and a windshield washer switch 42c as hardware buttons. The light switch 42a is a switch for turning the lights mounted on the outside of the cab 10 on and off. The wiper switch 42b is a switch for turning the wipers on and off. The windshield washer switch 42c is a switch for spraying windshield washer fluid.
[0053] The display device 40 operates by receiving power from the storage battery 70. The storage battery 70 is charged with electricity generated by the alternator 11a. Power from the storage battery 70 is also supplied to electrical components 72 other than the controller 30 and the display device 40. The starter 11b of the engine 11 is driven by power from the storage battery 70 to start the engine 11.
[0054] The engine control device 74 controls the engine 11. In this embodiment, the engine control device 74 collects various data indicating the status of the engine 11 and transmits the collected data to the controller 30. The engine control device 74 and the controller 30 are configured as separate units, but they may be configured as an integrated unit. For example, the engine control device 74 may be integrated into the controller 30.
[0055] The engine speed adjustment dial 75 is a dial for adjusting the engine speed. In this embodiment, the engine speed adjustment dial 75 is installed inside the carburetor 10 and is configured to allow switching of the engine speed in four stages. Specifically, the engine speed adjustment dial 75 is configured to allow switching of the engine speed in four stages: SP mode, H mode, A mode, and idling mode. Figure 2 shows the state in which H mode is selected on the engine speed adjustment dial 75.
[0056] SP mode is the rotation speed mode selected when prioritizing work volume, and utilizes the highest engine speed. H mode is the rotation speed mode selected when balancing work volume and fuel efficiency, and utilizes the second highest engine speed. A mode is the rotation speed mode selected when prioritizing fuel efficiency and operating the work machine with low noise, and utilizes the third highest engine speed. Idling mode is the rotation speed mode selected when you want to operate the engine at idle, and utilizes the lowest engine speed (idling speed).
[0057] The engine 11 is controlled to maintain an engine speed corresponding to the speed mode set by the engine speed adjustment dial 75. The engine speed adjustment dial 75 outputs data indicating the engine speed setting to the controller 30.
[0058] Furthermore, the controller 30 includes an angle control unit 31, a center of gravity calculation unit 32, a center of gravity storage unit 33, a weight calculation unit 34, and a cumulative weight calculation unit 35.
[0059] The angle control unit 31 controls the operation of the lifting magnet cylinder 9 to control the angle of the lifting magnet 6.
[0060] The center of gravity calculation unit 32 calculates the position of the center of gravity of the conveyed object attracted to the lifting magnet 6. In this embodiment, the center of gravity calculation unit 32 acquires detected values of the cylinder pressure of the boom cylinder 7 at each of several rotation angles of the lifting magnet 6, which is rotated with respect to a pin P7 (an example of a rotation mechanism) described later, while the conveyed object is attracted to the lifting magnet 6. Then, the center of gravity calculation unit 32 calculates the position of the center of gravity of the conveyed object attracted to the lifting magnet 6 based on the acquired cylinder pressures. The specific calculation method will be described later.
[0061] The center of gravity memory unit 33 is a memory area provided in a non-volatile memory medium located inside the controller 30, and stores information indicating the position of the center of gravity of the transported object, which is calculated by the center of gravity calculation unit 32.
[0062] In this embodiment, the center of gravity memory unit 33 stores information including the position of the center of gravity calculated for the first conveyed object that is attracted to the lifting magnet 6. Subsequently, the weight calculation unit 34 measures the weight of a second conveyed object, which is attracted to the lifting magnet 6 but is different from the first conveyed object, based on the position of the center of gravity stored in the center of gravity memory unit 33. The first and second conveyed objects are, for example, scrap materials with uniform shear dimensions. Therefore, the positions of the centers of gravity of the first and second conveyed objects are approximately the same.
[0063] The weight calculation unit 34 calculates the weight (current weight) of the conveyed object attracted to the lifting magnet 6. The current weight is calculated, for example, by the balance of torque around the base of the boom 4. Specifically, the thrust of the boom cylinder 7 increases due to the conveyed object attracted to the lifting magnet 6, and the torque around the base of the boom 4, calculated from the thrust of the boom cylinder 7, also increases. The increase in torque matches the weight of the conveyed object and the torque calculated from the center of gravity of the conveyed object. In this way, the weight calculation unit 34 calculates the weight of the conveyed object based on the thrust of the boom cylinder 7 (measured values from the boom rod pressure sensor S6a and boom bottom pressure sensor S6b) and the position of the center of gravity of the conveyed object stored in the center of gravity memory unit 33.
[0064] The cumulative weight calculation unit 35 calculates the cumulative weight of the transported goods loaded onto the dump truck bed. In this embodiment, each time a transported item of the weight calculated by the weight calculation unit 34 is loaded onto the dump truck, the cumulative weight calculation unit 35 adds the weight calculated by the weight calculation unit 34 to the cumulative weight up to the previous load.
[0065] Next, using Figure 3, a method for calculating the weight of a conveyed object attracted to the lifting magnet 6 in the weight calculation unit 34 of the work machine 100 according to this embodiment will be described.
[0066] Figure 3 is a schematic diagram illustrating the parameters for calculating the weight of the object to be lifted by the attachment of the work machine 100. Figure 3 shows the work machine 100 in this embodiment when it lifts an object.
[0067] When the work machine 100 lifts an object using the lifting magnet 6, the work machine 100 typically lifts the object with the boom 4 lowered, the arm 5 closed, and the lifting magnet 6 open, compared to the posture shown in Figure 1. The attachment is cantilevered to the upper slewing body 3 on the foot pin side of the boom 4. A heavy lifting magnet 6 is attached to the tip of the attachment. Next, the specific configuration of the work machine 100 will be described.
[0068] In this embodiment of the work machine 100, pin P1 connects the upper slewing body 3 and the boom 4. Pin P2 connects the upper slewing body 3 and the boom cylinder 7. Pin P3 connects the boom 4 and the boom cylinder 7. Pin P4 connects the boom 4 and the arm cylinder 8. Pin P5 connects the arm 5 and the arm cylinder 8. Pin P6 connects the boom 4 and the arm 5. Pin P7 connects the arm 5 and the lifting magnet 6.
[0069] Pin P7 functions as a rotation mechanism that rotates the lifting magnet 6.
[0070] Figure 3 shows the center of gravity G1 of the boom 4, the center of gravity G2 of the arm 5, the center of gravity G3 of the lifting magnet 6, and the center of gravity GS of the conveyed object attracted to the magnetic surface 6A of the lifting magnet 6.
[0071] Furthermore, the distance between pin P1 and the center of gravity G1 of boom 4 is defined as D1. The distance between pin P1 and the center of gravity G2 of arm 5 is defined as D2. The distance between pin P1 and the center of gravity G3 of lifting magnet 6 is defined as D3. The distance between pin P1 and the center of gravity GS of the conveyed object is defined as Ds. The distance between the line connecting pins P2 and P3 and pin P1 is defined as Dc. Furthermore, the detected cylinder pressure of boom cylinder 7 is defined as Fb. Furthermore, the vertical component of the boom weight perpendicular to the line connecting pin P1 and the center of gravity G1 of boom 4 is defined as W1a. The vertical component of the arm weight perpendicular to the line connecting pin P1 and the center of gravity G2 of arm 5 is defined as W2a. The weight of lifting magnet 6 is defined as W3, and the weight of the conveyed object attracted to the magnet surface 6A of lifting magnet 6 is defined as Ws.
[0072] As shown in Figure 3, the position of pin P7 is calculated based on the boom angle and arm angle. That is, the position of pin P7 can be calculated based on the detected values of the boom angle sensor S1 and the arm angle sensor S2.
[0073] Next, the equation for the balance between each moment around pin P1 and the boom cylinder 7 can be expressed by the following equation (1).
[0074] WsDs+W1aD1+W2aD2+W3D3=FbDc...(1)
[0075] The detected cylinder pressure Fb of the boom cylinder 7 is calculated by the boom rod pressure sensor S6a and the boom bottom pressure sensor S6b. The distance Dc and the vertical component weight W1a are calculated by the boom angle sensor S1. The vertical component weight W2a and distance D2 are calculated by the boom angle sensor S1 and the arm angle sensor S2. Distance D1 and weight W3 are known values. Also, the position of the center of gravity G3 of the lifting magnet 6 relative to pin P7 is a known value. Therefore, distance D3 is calculated from the boom angle sensor S1, the arm angle sensor S2, the lifting magnet angle sensor S3, and the position of the center of gravity G3.
[0076] As described above, the distance Ds is the distance between the pin P1 and the center of gravity GS of the conveyed object, and the position of the pin P1 is fixed (see Figure 3). Therefore, if the position of the center of gravity GS can be determined, the distance Ds can be determined. In other words, all values except the weight Ws of the conveyed object and the center of gravity GS of the conveyed object are calculable or known values. Therefore, once the center of gravity GS of the conveyed object is calculated (in other words, once the distance Ds is determined), the weight calculation unit 34 can calculate the weight Ws of the conveyed object from the following equation (2), which is obtained by expanding equation (1) for the weight Ws of the conveyed object.
[0077] Ws=(FbDc-(W1aD1+W2aD2+W3D3)) / Ds ···(2)
[0078] In other words, the weight Ws of the conveyed object can be calculated based on the center of gravity GS of the conveyed object, which is stored in the center of gravity memory unit 33, the detected cylinder pressure of the boom cylinder 7 (detected values from boom rod pressure sensor S6a and boom bottom pressure sensor S6b), the boom angle (detected value from boom angle sensor S1), and the arm angle (detected value from arm angle sensor S2). The center of gravity GS of the conveyed object, which is stored in the center of gravity memory unit 33, is calculated by the center of gravity calculation unit 32, which will be described later.
[0079] Next, the calculation of the center of gravity GS of the conveyed object by the center of gravity calculation unit 32 will be explained. In equation (1) described above, all values except the weight Ws of the conveyed object and the distance Ds from the center of gravity GS of the conveyed object are calculable or known values. On the other hand, the angle control unit 31 can change the position of the center of gravity GS of the conveyed object and the center of gravity G3 of the lifting magnet 6 by controlling the angle of the lifting magnet 6. In other words, by changing the angle of the lifting magnet 6, the weight Ws of the conveyed object and the position of the center of gravity GS of the conveyed object (for calculating the distance Ds) can be calculated from the multiple equations (1) derived.
[0080] Figure 4 is an example of a lifting magnet 6 whose angle is controlled by the angle control unit 31 according to this embodiment.
[0081] In the example shown in Figure 4, the angle control unit 31 controls the rotation of the lifting magnet 6 by +90 degrees and -90 degrees around the pin P7, with the angle at which the magnetic surface 6A of the lifting magnet 6 is approximately parallel to the horizontal plane being 0 degrees.
[0082] At position 6a, where the angle control unit 31 has controlled the lifting magnet 6 to rotate by "90 degrees", the center of gravity of the lifting magnet 6 becomes center of gravity G3a, and the center of gravity of the conveyed object becomes center of gravity Gsa. The position of the center of gravity G3a of the lifting magnet 6 is a known value.
[0083] At position 6b, where the angle control unit 31 controls the rotation of the lifting magnet 6 to "0 degrees", the center of gravity of the lifting magnet 6 becomes center of gravity G3b, and the center of gravity of the conveyed object becomes center of gravity GSb. The position of the center of gravity G3b of the lifting magnet 6 is a known value.
[0084] At position 6c, where the angle control unit 31 has controlled the lifting magnet 6 to rotate by "-90 degrees", the center of gravity of the lifting magnet 6 becomes center of gravity G3c, and the center of gravity of the conveyed object becomes center of gravity GSc. The position of the center of gravity G3c of the lifting magnet 6 is a known value.
[0085] In the example shown in Figure 4, the weight Ws of the conveyed object does not change even when the rotation angle of the lifting magnet 6 changes to "-90 degrees", "0 degrees", and "90 degrees". On the other hand, the centers of gravity Gsa, GSb, and GSc of the conveyed object change in accordance with the change in the rotation angle of the lifting magnet 6 to "-90 degrees", "0 degrees", and "90 degrees". However, the distance Ls from the pin P7 to the centers of gravity Gsa, GSb, and GSc of the conveyed object are all the same, only the angle differs. In other words, the distance from the center of gravity G3 of the lifting magnet 6 to the centers of gravity Gsa, GSb, and GSc of the conveyed object is also the same.
[0086] In this embodiment, the case in which the angle control unit 31 changes the rotation angle of the lifting magnet 6 has been described. The control of changing the rotation angle of the lifting magnet 6 in this embodiment is not limited to a method that is automatically performed by the angle control unit 31 of the controller 30. For example, the angle control unit 31 of the controller 30 may perform control to change the rotation angle of the lifting magnet 6 according to an operation from the operator input to the operating device 26.
[0087] Even if the weight Ws of the conveyed object does not change, the detected cylinder pressure Fb of the boom cylinder 7 changes in accordance with the changes in the center of gravity GSa, GSb, and GSc of the conveyed object. Therefore, based on this change, the position of the center of gravity of the conveyed object can be calculated from equation (1).
[0088] The center of gravity calculation unit 32 according to this embodiment calculates the position of the center of gravity GS of the conveyed object based on the above requirements, the detected cylinder pressure values of the boom cylinder 7 detected at rotation angles of "-90 degrees", "0 degrees", and "90 degrees" of the lifting magnet 6, and equation (1). For example, the center of gravity calculation unit 32 calculates the position of the center of gravity GS of the conveyed object where the standard deviation is minimized so that the weight Ws of the conveyed object is the same, by convergence calculation of three equations (1) with the respective parameters of rotation angles "-90 degrees", "0 degrees", and "90 degrees".
[0089] In this embodiment, the position of the center of gravity GS of the conveyed object is determined based on the distance from the center of gravity G3 of the lifting magnet 6 to the center of gravity GS of the conveyed object. The controller 30 in this embodiment can calculate the distance Ds between the pin P1 and the center of gravity GS of the conveyed object, using the distance D3 between the pin P1 and the center of gravity G3 of the lifting magnet 6, the position of the center of gravity GS, and the rotation angle of the lifting magnet 6.
[0090] The center of gravity memory unit 33 stores the position of the center of gravity GS of the conveyed object, which is calculated by the center of gravity calculation unit 32. The position of the center of gravity GS of the conveyed object is expressed, for example, as the distance and direction to the center of gravity GS of the conveyed object, with respect to the center of gravity G3 of the lifting magnet 6.
[0091] In this embodiment, the position of the center of gravity GS of the conveyed object, calculated by the center of gravity calculation unit 32, is not limited to the distance from the center of gravity G3 of the lifting magnet 6 to the center of gravity GS of the conveyed object, but can be any position where the distance Ds between the pin P1 and the center of gravity GS of the conveyed object can be calculated.
[0092] Incidentally, at each work site, the scrap material to be transported (an example of transported material) is typically sheared so that its shear dimensions are uniform. Therefore, as long as the work machine 100 is transporting scrap material with uniform shear dimensions at the work site, the position of the center of gravity GS of the scrap material attracted by the lifting magnet 6 will be approximately the same.
[0093] Therefore, in the work machine 100 according to this embodiment, when conveying scrap material that has been sheared in the same process, the weight calculation unit 34 calculates the weight of the scrap material (an example of conveyed material) based on the position of the center of gravity GS stored in the center of gravity memory unit 33 and equation (2).
[0094] Next, the initial setup process flow until the work machine 100 stores the center of gravity of the conveyed object will be explained. Figure 5 is a flowchart showing an example of the initial setup process flow until the work machine 100 according to this embodiment stores the center of gravity of the conveyed object.
[0095] The controller 30 controls the attraction of the conveyed object by the lifting magnet 6 by outputting an attraction command to the power control device 64 in response to the operation from the lifting magnet switch 65 (S501).
[0096] After picking up the object to be transported, the controller 30 performs lifting control of the picked-up object when it receives a press of the "Estimate Center of Gravity" button from the operator (S502). The lifting control performed by the controller 30 to calculate the center of gravity is performed at a slower speed (extremely slow speed) than the normal lifting speed of the transported object. This suppresses vibrations and other issues that occur during lifting, thereby improving the accuracy of the center of gravity calculation.
[0097] Subsequently, the angle control unit 31 controls the angle of the lifting magnet 6 (S503). In this flowchart, the angle of the lifting magnet 6 is controlled in the order of "90 degrees", "0 degrees", and "-90 degrees".
[0098] The center of gravity calculation unit 32 then measures and acquires the detected value Fb of the cylinder pressure of the boom cylinder 7, which corresponds to the angle of the lifting magnet 6 (S504).
[0099] The center of gravity calculation unit 32 then determines whether or not the measurement of the cylinder pressure of the boom cylinder 7 has been completed for all three positions of the lifting magnet 6 ("90 degrees", "0 degrees", and "-90 degrees") (S505). If the measurement for all three positions has not been completed (S505: No), the process returns to S503.
[0100] On the other hand, when the center of gravity calculation unit 32 has finished measuring all three positions (S505: Yes), it calculates the position of the center of gravity of the conveyed object based on the detected value Fb of the cylinder pressure of the boom cylinder 7, which is measured for each angle of the lifting magnet 6, and equation (1) (S506).
[0101] The center of gravity calculation unit 32 then stores the calculated position of the center of gravity of the transported object in the center of gravity storage unit 33 (S507).
[0102] Through the processing procedure described above, the position of the center of gravity of the conveyed object is stored in the center of gravity memory unit 33. Then, each time the work machine 100 attracts the conveyed object to the lifting magnet 6, the weight calculation unit 34 can calculate the weight of the conveyed object by using the position of the center of gravity of the conveyed object stored in the center of gravity memory unit 33.
[0103] In this embodiment, an example was described in which the position of the center of gravity of the conveyed object is measured using three angles (three positions) of the lifting magnet 6. However, the method of calculating the position of the center of gravity of the conveyed object is not limited to measurement based on three positions. For example, if there are two unknowns, the weight of the conveyed object and the position of the center of gravity of the conveyed object, the position of the center of gravity may be calculated using two angles (two positions) and equation (1). Furthermore, the position of the center of gravity may be calculated by convergence calculation using four or more angles (four or more positions).
[0104] Furthermore, if the shear dimensions of the transported material (e.g., scrap material) are changed, or if the shape of the transported material (e.g., scrap material) is changed, the center of gravity calculation unit 32 will recalculate the position of the center of gravity of the transported material.
[0105] Furthermore, this embodiment is not limited to methods for calculating the center of gravity of a conveyed object when its shear dimension or shape is changed. For example, the center of gravity may be calculated from the conveyed object when the operator presses the "Estimate Center of Gravity" button at any time, or the position of the weight may be calculated each time the conveyed object is attracted to the lifting magnet 6. In this way, the center of gravity calculation unit 32 calculates the position of the center of gravity of the conveyed object when any conditions are met.
[0106] Furthermore, in this embodiment, the transported material is not limited to scrap material, but can be any object that can be attracted to the lifting magnet 6. The transported material may be, for example, industrial waste such as scrap iron that does not require shearing. For example, when industrial waste discharged from the same work site is attracted to the lifting magnet 6, the weight calculation unit 34 calculates the weight of the transported material by using the position of the center of gravity of the transported material stored in the center of gravity storage unit 33, assuming that the centers of gravity are approximately the same.
[0107] The controller 30 according to this embodiment can suppress errors in weight measurement caused by errors in the center of gravity of the conveyed object by calculating the weight of the conveyed object based on the calculated position of the center of gravity of the conveyed object. This improves the accuracy of detecting the weight of the conveyed object.
[0108] (Second embodiment) In the embodiments described above, an example was given in which the center of gravity calculation unit 32 calculates the position of the center of gravity of the conveyed object. However, the method for determining the position of the center of gravity of the conveyed object is not limited to the calculation method shown in the first embodiment. Therefore, in the second embodiment, a method for calculating the center of gravity of the conveyed object based on the shape of the conveyed object will be described.
[0109] First, as in the first embodiment, after the lifting magnet 6 attracts the object to be transported, the controller 30 performs lifting control of the attracted object when it receives a press of the "center of gravity estimation" button from the operator.
[0110] The spatial recognition device 80, while attached to the lifting magnet 6, captures an image of the lifted object. The spatial recognition device 80 then transmits the image data to the controller 30. In this embodiment, an example is described in which the spatial recognition device 80 captures an image of the lifted object, but other methods may be used as long as the shape of the lifted object can be recognized.
[0111] The center of gravity calculation unit 32 then recognizes the shape of the transported object based on the imaging data (an example of the recognition result) from the spatial recognition device 80, and calculates the position of the center of gravity of the transported object that is attracted to the lifting magnet 6 based on the recognized shape of the transported object. The estimated position of the center of gravity of the transported object is stored in the center of gravity storage unit 33.
[0112] The subsequent processing performed by the controller 30 is the same as in the first embodiment, and therefore will not be described further.
[0113] The controller 30 according to this embodiment stores the position of the center of gravity of the conveyed object, and, similar to the first embodiment, can calculate the weight of the conveyed object based on the calculated position of the center of gravity of the conveyed object. As a result, the controller 30 according to this embodiment can suppress errors in weight measurement due to errors in the center of gravity of the conveyed object and improve the accuracy of detecting the weight of the conveyed object.
[0114] (Third embodiment) In the embodiments described above, an example was explained in which the position of the center of gravity of a conveyed object is estimated and the weight of the conveyed object is measured based on the position of the center of gravity. However, the method for determining the position of the center of gravity of a conveyed object when measuring its weight is not limited to that method.
[0115] In the third embodiment, with the object being transported attached to the lifting magnet 6, the weight calculation unit 34 calculates the weight of the object while the lifting magnet cylinder 9 controls the rotation mechanism including the pin P7 so that the magnet surface 6A that is holding the object attached to the lifting magnet 6 remains substantially parallel to the horizontal plane.
[0116] In the third embodiment, when moving a transported object that has been attracted to the lifting magnet 6, the angle control unit 31 controls the angle of the lifting magnet 6 so that the magnet surface 6A that is attracting the transported object remains substantially parallel to the horizontal plane (in other words, substantially perpendicular to the vertical direction).
[0117] In other words, in this embodiment, the magnet surface 6A that attracts the conveyed object maintains a state that is approximately parallel to the horizontal plane (in other words, approximately perpendicular to the vertical direction), so that the conveyed object is located vertically below the lifting magnet 6. Therefore, the position of the center of gravity of the conveyed object and the position of the center of gravity of the lifting magnet 6 in the X1-X2 direction shown in Figure 4 are approximately the same. That is, in equation (1), the distance D3 between the pin P1 and the center of gravity G3 of the lifting magnet 6 are approximately the same as the distance Ds between the pin P1 and the center of gravity GS of the conveyed object.
[0118] Therefore, as in this embodiment, when the magnet surface 6A that attracts the conveyed object maintains a state that is substantially parallel to the horizontal plane, the weight calculation unit 34 according to this embodiment applies the fact that distance D3 and distance Ds are substantially the same to equation (2) and calculates the weight of the conveyed object.
[0119] In this embodiment, the controller 30 maintains a state in which the magnet surface 6A that attracts the conveyed object is substantially parallel to the horizontal plane, thereby enabling more accurate calculation of the weight of the conveyed object compared to the case where the magnet surface 6A is not parallel to the horizontal plane.
[0120] Furthermore, in this embodiment, the magnet surface 6A that attracts the conveyed object is controlled to maintain a state that is substantially parallel to the horizontal plane.
[0121] In this embodiment, the control of the lifting magnet 6 in the work machine 100 suppresses changes in angular orientation due to inertial force, and thus suppresses vibration generation near the lifting magnet 6, compared to a control that releases the hydraulic pressure of the lifting magnet cylinder 9 to control the posture of the lifting magnet 6 and suppresses the force applied to the lifting magnet 6 from the work machine. As a result, the controller 30 according to this embodiment can improve the accuracy of detecting the gravity of the conveyed object. Note that the control that releases the hydraulic pressure of the lifting magnet cylinder 9 means a control that connects the lifting magnet cylinder 9 to the hydraulic oil tank, that is, a control that attempts to keep the magnet surface 6A of the lifting magnet 6 always vertical by utilizing the weight of the lifting magnet 6.
[0122] In the above-described embodiment, by improving the accuracy of the controller 30's calculation of the weight of the transported goods, rework in weighing adjustments can be reduced, thereby improving the work efficiency at the loading site. Furthermore, the controller 30 according to the above embodiment can load the transported goods up to near the upper limit that the dump truck can load without causing overloading, thus improving transportation efficiency. Moreover, the controller 30 according to the above embodiment can suppress overloading of the transported goods on the dump truck, thus suppressing road damage caused by the load of overloading.
[0123] In the embodiments described above, an example of a working machine using a hydraulic excavator to which a lifting magnet 6 is attached is explained, but it is not limited to hydraulic excavators. For example, it may be applied to construction machinery, standard machines, applied machines, forestry machinery, or conveying machines based on hydraulic excavators.
[0124] Although embodiments of the work machine according to the present invention have been described above, the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope described in the claims. These also naturally fall within the technical scope of the present invention. [Explanation of Symbols]
[0125] 100 working machines 1. Lower running body 2. Swivel mechanism 3. Upper rotating body 4. Boom (attachment) 5. Arm (attachment) 6 Lifting Magnets 7 Boom Cylinder 8 Arm Cylinder 9. Lifting Magnet Cylinder 30 controllers 31 Angle Control Unit 32 Center of gravity calculation section 33 Center of gravity memory 34 Weight calculation section 35. Cumulative Weight Calculation Section
Claims
1. An attachment that is mounted on the upper rotating body, A lifting magnet is provided at the tip of the aforementioned attachment, It has a storage unit that stores the position of the center of gravity of the conveyed object attracted to the lifting magnet, In the initial setup process, the position of the center of gravity is calculated from the first transported object attracted to the lifting magnet, and the calculated position of the center of gravity is stored in the memory unit. When a second object, separate from the first object, is attracted to the lifting magnet, the weight of the second object is calculated based on the position of the center of gravity stored in the memory unit. Agricultural machinery.
2. A hydraulic cylinder for driving the aforementioned attachment, The attachment further includes a rotating mechanism for rotating the lifting magnet, located on the upper rotating body side of the lifting magnet. With the object being transported attached to the lifting magnet, the lifting magnet is rotated by the rotation mechanism, and the position of the center of gravity of the object attached to the lifting magnet is calculated based on the cylinder pressure of the hydraulic cylinder measured at each of a plurality of rotation angles, and the weight of the object being transported is calculated based on the calculated position of the center of gravity. The work machine according to claim 1.
3. In the initial setup process, if predetermined conditions are met, the position of the center of gravity is calculated from the first transported object that has been attracted to the lifting magnet, and the calculated position of the center of gravity is stored in the storage unit. The work machine according to claim 1.
4. The system further includes a spatial recognition device capable of recognizing the conveyed object that has been attracted to the lifting magnet, Based on the recognition results from the spatial recognition device, the position of the center of gravity of the transported object attracted to the lifting magnet is calculated. The work machine according to claim 1.