Working machine

Abstract

To provide a work machine capable of accurately grasping the position of a suspended load relative to the work machine.SOLUTION: A work machine (100) is capable of suspending a load. The work machine (100) includes: a measurement unit (20, 21, 22, 23) that measures a position of a suspended load (N) relative to the work machine (100); and a control unit (40) that calibrates the measurement unit (20, 21, 22, 23).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a working machine capable of lifting a load.

Background Art

[0002] Patent Document 1 describes a detection device that is attached to a crane and detects the spatial position and orientation of a boom. The detection device performs the above detection by measuring the distance and direction to a target mark provided at the tip of the boom.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a working machine that lifts a load to perform work, it is preferable to accurately grasp the position of the suspended load with respect to the working machine.

[0005] An object of the present invention is to provide a working machine that can more accurately grasp the position of a suspended load with respect to the working machine.

Means for Solving the Problems

[0006] (1) The present invention One aspect related to is a working machine capable of lifting a load, a measurement unit for measuring the position of the suspended load with respect to the working machine, a control unit for calibrating the measurement unit, and includes 、 The measurement unit includes a boom angle measurement unit, a rope length measurement unit that measures the payout length of the rope for suspending the load, or both of them. The control unit calibrates the boom angle measurement unit, the rope length measurement unit, or both of them, and calibrates the boom angle measurement unit when the boom reaches a predetermined angle. it. (2) Another aspect of the present invention is a work machine capable of suspending a load, a measurement unit for measuring the position of the suspended load with respect to the work machine, a control unit for calibrating the measurement unit, comprising: The measurement unit includes a first positioning device attached to the boom and a second positioning device attached to the suspended load or the lifting tool. The control unit calibrates the first positioning device, the second positioning device, or both of them by adding an offset to the positioning data.

Advantages of the Invention

[0007] According to the present invention, an effect can be obtained that the position of the suspended load on the working machine can be accurately grasped.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification, the position of the suspended load means the position of the load when the load is being suspended, while when the load is not being suspended, it means the position of the lifting tool (for example, a hook) 107. Also, the payout length of the rope for raising and lowering the lifting tool 107 (the length of the portion paid out beyond the point sheave 106a) is referred to as the "rope length".

[0010] (Embodiment 1) FIG. 1 shows a working machine according to Embodiment 1 of the present invention, where (A) is a side view and (B) is a plan view. In FIG. 1(B), the boom 106, the rope (wire rope), etc. are omitted. FIG. 2 is a block diagram showing the configuration of the control system of the working machine.

[0011] The working machine 100 of Embodiment 1 is a mobile crane, and includes a lower traveling body 102, an upper slewing body 104 that can slew with respect to the lower traveling body 102, a boom 106 that can be raised and lowered with respect to the upper slewing body 104, and a lifting tool 107 suspended from the tip of the boom 106. A cab 112, which is a driver's cab, is provided on the upper slewing body 104. Further, the working machine 100 includes a plurality of winches 114 that respectively wind and pay out the rope for raising and lowering the lifting tool 107, and wind and pay out the rope for raising and lowering the boom 106.

[0012] As shown in FIG. 2, the cab 112 may be provided with, in addition to the operation control unit 115, an operation unit 116 for switching the operation mode, a display device 117 capable of outputting various videos or images, and a notification unit 118 for notifying various information by sound and display.

[0013] The working machine 100 further includes a boom overwind prevention device (for example, a backstop) 108 that limits overrotation in the raising and lowering direction of the boom 106, and a hook overwind prevention device 109 that limits overraising of the lifting tool 107.

[0014] The boom overwind prevention device 108 restricts the boom 106 from over-rotating in the raising and lowering direction by locking the boom 106 so that the angle of the boom 106 in the raising and lowering direction stops at a set angle. The boom overwind prevention device 108 includes a buffer mechanism so that no impact is applied when the boom 106 is locked. However, when the boom 106 stops due to the operation of the boom overwind prevention device 108, the boom 106 is configured to stop stably at the set angle. Further, when the boom overwind prevention device 108 locks the boom 106, it outputs a signal indicating the locking to the control unit 40.

[0015] The hook overwind prevention device 109 is a limit switch for stopping the winding of the wire rope that suspends the spreader 107 when the spreader 107 rises to a position at a set length from the point sheave 106a. When the hook overwind prevention device 109 operates due to the raising of the spreader 107 and the spreader 107 stops, the rope length is configured to stably become the set length.

[0016] As shown in FIG. 2, the working machine 100 includes a measurement unit 20 for measuring the position of the suspended load with respect to the working machine 100, a calculation unit 30 for calculating the position of the suspended load based on the measurement result of the measurement unit 20, and a control unit 40 for controlling the working machine 100. The control unit 40 is a computer, and the calculation unit 30 may be a part of the control unit 40.

[0017] The measurement unit 20 includes a photographing device 21 attached to the boom 106, a boom angle measurement unit 22 for measuring the raising and lowering angle of the boom 106, and a rope length measurement unit 23 for measuring the rope length of the spreader 107 (the payout length of the rope for raising and lowering the spreader 107).

[0018] The photographing device 21 is a digital photographing device having a lens and an imaging element, etc. When the photographing direction is known, the direction of the suspended load N can be obtained from the coordinate values (x1, y1) where the suspended load N is located in the video E (see FIG. 3(B)). The photographing device 21 is attached at a predetermined angle around the tip of the boom 106 so that the suspended load N enters the viewing angle.

[0019] The attachment angle of the imaging device 21 may be variable by driving a movable device 21F (such as a servo motor). Further, when the imaging device 21 is attached to the boom 106 via a slide mechanism such as a rack and pinion, the fixed position of the imaging device 21 may be variable by driving a movable device 21F (such as a servo motor). In the case of such a configuration, the attachment angle and attachment position of the imaging device 21 can be obtained based on data representing the driving amount of each servo motor.

[0020] The video E of the imaging device 21 may be output to the display device 117 in the cab 112, and a configuration may be adopted such that an operator can check the suspended load N from the video E.

[0021] The boom angle measurement unit 22 may have any configuration as long as it can measure the elevation angle of the boom 106, such as an encoder that detects the rotation amount of a winch 114 that winds and unwinds a rope for raising and lowering the boom 106, a protractor attached to the boom 106, or an encoder that detects the rotation amount of the boom 106 at the rotation center of the boom 106.

[0022] The rope length measurement unit 23 measures the length of the rope paid out from the tip of the boom 106. More specifically, the rope length may be defined as, for example, the length from the end point where the rope separates at the point sheave 106a to a predetermined point on the spreader 107. The rope length measurement unit 23 may have any configuration as long as it outputs a signal capable of measuring the rope length, such as an encoder that detects the rotation amount of a winch 114 that raises and lowers the spreader 107, or an encoder that detects the rotation amount of the point sheave 106a.

[0023] Video data is sent from the imaging device 21 to the calculation unit 30. When the attachment angle, attachment position, or both of the imaging device 21 are variable, data indicating the attachment angle, attachment position, or both is sent from the control unit 40 that controls the attachment angle and attachment position to the calculation unit 30. Further, measurement data from the boom angle measurement unit 22 and the rope length measurement unit 23 is sent to the calculation unit 30.

[0024] The calculation unit 30 calculates the relative position of the suspended load N with the tip of the boom 106 as the reference point P0 according to the following principle. FIG. 3 is a diagram for explaining the calculation principle of the position of the suspended load, where (A) is a diagram showing the arrangement relationship of the boom, the imaging device, and the suspended load, and (B) is a diagram showing the image of the imaging device.

[0025] Based on the measurement data of the boom angle measurement unit 22, the calculation unit 30 obtains the angle θ of the boom 106. boom Furthermore, the calculation unit 30 obtains the rope length L from the measurement data of the rope length measurement unit 23. hook

[0026] Furthermore, based on the data of the attachment position and attachment angle of the imaging device 21, the calculation unit 30 obtains the length L from the reference point P0 of the boom 106 to the attachment position P1 of the imaging device 21, cam1 and the attachment angle θ. cam0 The length L from the attachment position P1 to the center point P2 of the viewing angle is a constant value, and the calculation unit 30 holds the value of the length L in advance. cam2 cam2

[0027] Based on the length L cam1 and the angle θ of the boom 106, boom the calculation unit 30 calculates the vector A from the reference point P0 to the attachment position P1. cam1 Furthermore, based on the length L cam2 , the attachment angle θ of the imaging device 21, cam0 , and the angle θ of the boom 106, boom the calculation unit 30 calculates the vector A from the attachment position P1 to the center point P2 of the viewing angle. cam2

[0028] Furthermore, the calculation unit 30 performs image recognition on the suspended load from the video data and obtains the coordinate values (x1, y1) of the suspended load N in the video E (FIG. 3(B)). The image recognition may be replaced by recognition using a machine-learned learning model (artificial intelligence). Then, the calculation unit 30 calculates the angles θ from the imaging center line L corresponding to the coordinate values (x1, y1), cam0 θ, camx θ, camyCalculate the angle θ. camx , θ camy corresponds to the angle in the x direction and the angle in the y direction within the viewing angle of the imaging device 21, and is associated one-to-one with the coordinate values in the video.

[0029] Furthermore, the calculation unit 30 geometrically calculates the intersection point of the spherical surface Sn with the rope length L as the radius centered on the reference point P0 and the straight line extending from the viewing angle center point P2 at the angles θ hook , θ camx , θ camy . Then, the calculation unit 30 calculates the distance from the viewing angle center point P2 to the above intersection point. Furthermore, from the said distance and the angles θ camx , θ camy , θ boom , θ cam0 , the vector A from the viewing angle center point P2 to the suspended load N CtoN is calculated.

[0030] By the above calculation, when the vectors A cam1 , A cam2 , A CtoN are obtained, the calculation unit 30 synthesizes these vectors A cam1 , A cam2 , A CtoN to obtain the relative position of the suspended load N with respect to the tip of the boom 106 (reference point P0) (= A cam1 + A cam2 + A CtoN ). The calculation unit 30 sends the calculation result of the relative position of the suspended load N to the control unit 40.

[0031] In this way, since the control unit 40 of the working machine 100 can accurately grasp the relative position of the suspended load N, the control unit 40 can calculate various useful physical quantities. For example, separately, when data on the weight of the suspended load N is given, from these data, the control unit 40 can determine in which direction and how much load is applied to the boom 106 when the suspended load N sways.

[0032] In addition to controlling the operation of the working machine 100, the control unit 40 performs calibration processing of the measurement unit 20.

[0033] <Calibration process> As described above, the calculation unit 30 can accurately determine the relative position of the suspended load N based on the measurement data of the measurement unit 20. On the other hand, systematic errors may be added to the measurement data of the measurement unit 20. For example, in the boom angle measurement unit 22, systematic errors may occur in the measurement data, such that a substantially constant deviation is added to the true undulation angle. Similarly, in the rope length measurement unit 23, systematic errors may occur in the measurement data, such that a substantially constant deviation is added to the true rope length.

[0034] In such a case, the deviation between the true undulation angle of the boom 106 and the measurement data is measured, and by removing the deviation from the subsequent measurement data, the boom angle measurement unit 22 can be calibrated. Similarly, by measuring the deviation between the true rope length and the measurement data and removing the deviation from the subsequent measurement data, the rope length measurement unit 23 can be calibrated.

[0035] Further, when the imaging device 21 is fixedly attached to the boom 106, a deviation may occur in the attachment angle due to vibration or the like. Alternatively, when the imaging device 21 is movably attached to the boom 106, the attachment position, the attachment angle, or the control data of both may indicate a value deviated from the true value. In these cases, the above deviations are added as systematic errors to the angle or the like indicating the direction of the suspended load N calculated based on the video E.

[0036] In such a case, the deviation between the true attachment angle of the imaging device 21 and the attachment angle recognized by the control unit 40 is measured, and the control data of the subsequent attachment angle is corrected so that the deviation is removed, thereby calibrating the control data of the attachment angle used for the angle measurement by the imaging device 21. The same applies to the control data of the attachment position of the imaging device 21.

[0037] The control unit 40 executes the process of calibrating the systematic errors as described above for each element of the measurement unit 20 as follows.

[0038] In the calibration process of the boom angle measurement unit 22, the control unit 40 raises and lowers the boom 106 to a known angle by driving the winch 114, and measures the deviation occurring in the measurement data from the difference between the measurement data of the boom angle measurement unit 22 at that time and the known angle. Then, when the deviation is measured, the control unit 40 executes a calibration process so that a value obtained by subtracting the deviation from the measurement data of the boom angle measurement unit 22 is output.

[0039] The angle of the boom 106 at which the calibration process of the boom angle measurement unit 22 is performed may be a set angle when the boom overwind prevention device 108 restricts the rotation of the boom 106 in the raising and lowering direction. By adopting this angle, without adding a means for measuring the true angle of the boom 106 for calibration, the control unit 40 can obtain the true angle of the boom 106 and perform the calibration process of the boom angle measurement unit 22.

[0040] Note that in the calibration process of the boom angle measurement unit 22, instead of the control unit 40 driving the winch 114, the control unit 40 outputs support information to the operator of the work machine 100, and based on the support information, the operator drives the winch 114, and the boom 106 may be rotated to an angle at which calibration processing is possible, such as a raising and lowering angle. Further, the angle of the boom 106 at which the calibration process of the boom angle measurement unit 22 is performed is not limited to the above angle, and various predetermined angles may be adopted. For example, a part of the boom 106 is photographed by a camera from a fixed position, and based on the fact that the boom 106 is reflected at a predetermined position, the boom angle measurement unit 22 may be calibrated according to the angle of the boom 106 corresponding to the time of the photographing.

[0041] In the calibration process of the rope length measurement unit 23, the control unit 40 winds up (or pays out) the rope suspending the spreader 107 to a known length by driving the winch 114, and measures the deviation occurring in the measurement data from the difference between the measurement data of the rope length measurement unit 23 at that time and the known length. Then, when the deviation is measured, the control unit 40 executes a calibration process so that a value obtained by subtracting the deviation from the measurement data of the rope length measurement unit 23 is output.

[0042] The rope length for the calibration process of the rope length measurement unit 23 may be the set length of the rope when the hook overwind prevention device 109 restricts the upward movement of the spreader 107. By adopting the set length, without adding a means for measuring the true rope length for calibration, the control unit 40 can obtain the true rope length and perform the calibration process of the rope length measurement unit 23.

[0043] In addition, in the calibration process of the rope length measurement unit 23, instead of the control unit 40 driving the winch 114, the control unit 40 may output support information to the operator of the work machine 100, and based on the support information, the operator may drive the winch 114 to make the rope length a length that can be calibrated.

[0044] In the calibration process of the mounting angle of the imaging device 21, the control unit 40 uses an attitude sensor (for example, an IMU (Inertial Measurement Unit)) 25 attached to the imaging device 21. The attitude sensor 25 is attached to the imaging device 21, measures the angle of the imaging device 21 with respect to the horizontal, and outputs the measurement data to the control unit 40. The control unit 40 calculates the mounting angle of the imaging device 21 with respect to the boom 106 from the output of the attitude sensor 25 and the measurement result of the boom angle measurement unit 22. Then, the control unit 40 calculates the difference between the mounting angle held by the control unit 40 and the calculated mounting angle as the deviation with respect to the true mounting angle, and corrects the control data representing the mounting angle so that the deviation is removed, thereby performing the calibration process regarding the mounting angle.

[0045] Also, when the mounting position of the imaging device 21 is variable, the control unit 40 moves the imaging device 21 to a location where the position is known, such as one end of the movable range. That is, the control unit 40 drives the movable device 21F (a servo motor for movement) in one direction and stops the movable device 21F when the imaging device 21 and the servo motor can no longer move. Then, the control unit 40 calculates the difference between the mounting position of the imaging device 21 calculated from the control data of the servo motor at that time and the mounting position of the imaging device 21 obtained from the end point position of the slide mechanism as the deviation from the true mounting position. And the control unit 40 performs calibration processing regarding the mounting position by correcting the control data representing the mounting position so that the deviation is removed.

[0046] FIG. 4 is a diagram for explaining the calibration process of the coordinates of the video, and is a graph (A) showing the position change of the suspended load and a diagram (B) showing the coordinates before and after calibration.

[0047] The calibration process of the coordinates (x, y) in the video E of the imaging device 21 is performed as follows. That is, when the suspended load N with weak wind and little deviation of the center of gravity is suspended, the suspended load N performs a pendulum motion including components of swaying in two horizontal directions around the point directly below the tip of the point sheave 106a. And if we assume that the suspended load N is located at the center point of the pendulum motion, the rope suspending the spreader 107 should extend vertically downward.

[0048] Also, when the rope extends vertically downward, the rope length L hook , the angle θ of the boom 106 boom , the mounting position of the imaging device 21 (length L cam1 ) and the mounting angle θ cam0 , it is possible to calculate inversely at which coordinate position of the video E the suspended load N should be located.

[0049] Therefore, the control unit 40 calculates the true coordinate position where the above-mentioned suspended load N should be located and the coordinate position (x2, y2) of the center point of the pendulum motion of the suspended load N obtained from the actual video (FIGS. 4(A) and 4(B)), and obtains the difference between them as the coordinate deviation. The calculation for obtaining the coordinate position of the center point of the pendulum motion may be replaced by an acquisition process using a machine-learned learning model (artificial intelligence).

[0050] Then, the control unit 40 calibrates the origin of the coordinates so that the above-mentioned deviation is removed. Note that the coordinates (x, y) are projected onto the display device 117 overlaid with the video E, and the origin of the coordinates projected onto the display device 117 may also be corrected during the above-mentioned coordinate calibration. Alternatively, the coordinate calibration may be performed only for the coordinates in the video E recognized by the control unit 40 in internal processing (the data value of the coordinate origin included in the control data used by the control unit 40), and may not be reflected in the coordinates output to the display device 117.

[0051] <Calibration mode process> FIG. 5 is a flowchart showing the calibration mode process of Embodiment 1 executed by the control unit. The calibration process of the measurement unit 20 described above is executed when the operation mode of the machine tool 100 is switched to the calibration mode. The operation mode may be switchable to the calibration mode by an operator or the like operating the operation unit 116 provided in the cab 112. The operation unit 116 may be an operation unit projected onto a display screen such as a touch panel.

[0052] Also, the calibration mode may be controlled to be shiftable when predetermined conditions are satisfied, such as when the wind strength is below a predetermined level, when not in operation, when the spreader 107 is not on the ground, when the spreader 107 is not rotating, when the level of the work site is above a predetermined value, or when a plurality of these are satisfied. The machine tool 100 may be provided with an anemometer and a level to determine whether the conditions are satisfied.

[0053] When the calibration mode process is started by operating the operation unit 116, the control unit 40 first determines whether the conditions for shifting to the calibration mode are satisfied (step S1). If the result is YES, the control unit causes the notification unit 118 to output that it is in the calibration mode (step S2) and proceeds with the process. On the other hand, if the result of step S1 is NO, the control unit 40 ends the calibration mode process.

[0054] When the process proceeds, first, the control unit 40 executes the calibration process of the boom angle measurement unit 22 (step S3). In step S3, as an example, the control unit 40 outputs support information to rotate the boom 106 until the boom overwind prevention device 108 operates, and the operator rotates the boom 106 based on the support information. Then, with the boom overwind prevention device 108 operating and the boom 106 being stably set at the set angle, as described above, the control unit 40 performs the calibration process of the boom angle measurement unit 22.

[0055] Next, the control unit 40 executes the calibration process of the rope length measurement unit 23 (step S4). As an example, in step S4, the control unit 40 outputs support information to raise the spreader 107 until the hook overwind prevention device 109 operates, and the operator raises the spreader 107 based on the support information. Then, with the hook overwind prevention device 109 operating and the spreader 107 stopped and the rope length being stably set to the set length, as described above, the control unit 40 performs the calibration process of the rope length measurement unit 23.

[0056] By performing the calibration process of the rope length measurement unit 23 (step S4) after the calibration process of the boom angle measurement unit 22 (step S3), the required driving operations of the operator can be reduced. That is, when the boom 106 is rotated to the angle at which the boom overwind prevention device 108 operates, the rope suspending the spreader 107 is slightly pulled toward the point sheave 106a due to the rotation. Therefore, in order to rotate the boom 106 to the angle at which the boom overwind prevention device 108 operates, it is necessary to make the rope suspending the spreader 107 longer than the length at which the hook overwind prevention device 109 operates before that. Therefore, if the order of step S3 and step S4 is reversed, after the rope length becomes the set length in the calibration process of the rope length measurement unit 23, it is necessary to pay out the rope suspending the spreader 107 and then shift to the calibration process of the boom angle measurement unit 22. On the other hand, by setting the order from step S3 to step S4, the process of paying out the rope suspending the spreader 107 can be omitted.

[0057] Next, the control unit 40 executes the calibration process of the attachment angle and attachment position of the imaging device 21 (step S5). A specific example of the calibration process is as described above.

[0058] And finally, the control unit 40 executes the calibration process of the coordinates of the video E (step S6). A specific example of the calibration process is as described above.

[0059] Thereafter, the control unit 40 ends the output of the calibration mode from the notification unit 118 (step S7) and ends the calibration mode process.

[0060] By calibrating the measurement unit 20 through the above calibration mode process, it becomes possible to more accurately grasp the position of the suspended load N thereafter.

[0061] As described above, according to the working machine 100 of Embodiment 1, it includes a measurement unit 20 for measuring the position of the suspended load N with respect to the working machine 100, and a control unit 40 for calibrating the measurement unit 20. Therefore, systematic errors of the measurement unit 20 can be removed by calibration, and the working machine 100 can accurately grasp the position of the suspended load N by using accurate measurement data.

[0062] Furthermore, according to the working machine 100 of Embodiment 1, the control unit 40 calibrates the mounting angle, mounting position, and coordinates of the video E of the imaging device 21. Furthermore, the control unit 40 calibrates the boom angle measurement unit 22 and the rope length measurement unit 23. Therefore, the working machine 100 can accurately grasp the position of the suspended load N with respect to the boom 106 from the video data of the imaging device 21 and the measurement data of the boom angle measurement unit 22 and the rope length measurement unit 23.

[0063] Furthermore, according to the working machine 100 of Embodiment 1, based on the operation of the hook overwind prevention device 109, the calibration of the rope length measurement unit 23 is performed, so that stable calibration processing is possible. Furthermore, it is not necessary to add means for detecting that the rope length has reached a predetermined length for calibration processing.

[0064] Furthermore, according to the working machine 100 of Embodiment 1, when the boom 106 reaches a predetermined angle, the boom angle measurement unit 22 is calibrated, so that stable calibration processing is possible. Furthermore, the above-mentioned predetermined angle is the angle at which the boom overwind prevention device 108 operates. By setting such an angle, it is not necessary to add means for detecting that the boom 106 has reached a predetermined angle for calibration processing.

[0065] Furthermore, according to the working machine 100 of Embodiment 1, when the calibration mode is selected, the control unit 40 executes the calibration process of the measurement unit 20. Therefore, it is easy to perform accurate calibration under suitable conditions, and it is possible to suppress problems such as incorrect calibration processing being performed without the operator noticing.

[0066] (Embodiment 2) FIG. 6 is a view showing a working machine according to Embodiment 2 of the present invention. FIG. 7 is a block diagram showing the configuration of the control system of the working machine of FIG. 6. The working machine 100A of Embodiment 2 is the same as that of Embodiment 1 except for the elements of the measuring unit 20A for measuring the position of the suspended load N with respect to the working machine 100A and the content of the calibration process. The same elements are denoted by the same reference numerals as those in Embodiment 1, and detailed description thereof is omitted.

[0067] The measuring unit 20A of Embodiment 2 includes a rope length measuring unit 23 for measuring the rope length, a first position measuring device 26 attached to the boom 106, and a second position measuring device 27 attached to the spreader 107 or the suspended load N. The first position measuring device 26 may be attached, for example, to the reference point P0 of the boom 106 or its vicinity.

[0068] The first position measuring device 26 and the second position measuring device 27 are position measuring devices using GNSS (Global Navigation Satellite System). In the present embodiment, mainly the positioning data of latitude and longitude are used.

[0069] FIG. 8 is a view for explaining the measuring principle of the position of the suspended load in Embodiment 2. The calculation unit 30A acquires the horizontal positioning data (X P0 , Y P0 ) and (X hook , Y hook ) from the first position measuring device 26 and the second position measuring device 27, respectively. Further, the calculation unit 30A acquires the rope length L hook from the rope length measuring unit 23.

[0070] Then, from these data, the calculation unit 30A calculates the relative position A 0toN of the suspended load N with respect to the reference point P0 of the boom 106. That is, the horizontal distances in the X direction and the Y direction can be calculated from the positioning data (X P0 , Y P0 ) and (X hook , Y hook ). Further, the vertical distance in the Z direction is the positioning data (X P0 , Y P0 ), (X hook , Y hook ) and the rope length Lhook It can be geometrically calculated from this. And as components in the X, Y, and Z directions, a vector having the above distances in the X, Y, and Z directions is the position vector A from the reference point P0 to the suspended load N. 0toN , = (X 0toN , Y 0toN , Z 0toN ).

[0071] Note that the measurement unit 20A includes a direction finder that measures the direction in which the boom 106 is facing, and the calculation unit 30A may calculate the relative position of the suspended load N with respect to the reference point P0 of the boom 106 including the direction by associating the measurement result of the direction finder with the latitude and longitude data of the first position finder 26 and the second position finder 27.

[0072] The control unit 40A of the second embodiment executes the calibration process of the rope length measurement unit 23 and the calibration process of the mounting positions of the first position finder 26 and the second position finder 27. The calibration process of the rope length measurement unit 23 is as shown in the first embodiment.

[0073] The calibration process for the first position finder 26 and the second position finder 27 is performed as follows. That is, when the suspended load N with a weak wind and little bias in the center of gravity is suspended, the suspended load N performs a pendulum motion including components of swaying in two horizontal directions around the point directly below the tip of the point sheave 106a. And if the suspended load N is assumed to be located at the center point of the pendulum motion, the rope suspending the spreader 107 should extend vertically downward. That is, the first position finder 26 and the second position finder 27 should be located at the same latitude and longitude.

[0074] Therefore, the control unit 40A calculates the latitude and longitude of the center point of the pendulum motion from the positioning data of the second position measuring device 27. Further, the control unit 40A calculates the difference between the latitude and longitude indicated by the positioning data of the first position measuring device 26 and the latitude and longitude of the center point of the pendulum motion as the deviation of the mounting position of the first position measuring device 26 or the second position measuring device 27. Then, the control unit 40A offsets the positioning data of the first position measuring device 26 or the second position measuring device 27 so that the deviation is removed. This offset corresponds to the calibration process. Note that the first position measuring device 26 and the second position measuring device 27 may be attached at positions where the latitude and longitude differ by a predetermined deviation amount. In this case, the calibration process may be performed so that the positioning data is corrected by the offset amount obtained by adding the deviation amount. Further, the calibration processes of the first position measuring device 26 and the second position measuring device 27 may be performed based on the measurement result of measuring the actual positions of the first position measuring device 26 and the second position measuring device 27 or the deviation amount between their positions using other sensors.

[0075] Also in the second embodiment, the control unit 40A may be configured to execute the calibration process when the operation mode of the working machine 100 is switched to the calibration mode. The operation mode may be switchable to the calibration mode by an operator or the like operating an operation unit 116 provided in the cab 112. Further, the calibration mode may be controlled to be shiftable when a predetermined condition is satisfied, such as when the wind strength is below a predetermined level, when not in the driving operation, when the spreader 107 is not on the ground, when the spreader 107 is not rotating, when the levelness of the work site is above a predetermined value, or when a plurality of these conditions are satisfied.

[0076] As described above, according to the working machine 100A of the second embodiment, the working machine 100A includes a measuring unit 20A for measuring the position of the suspended load N with respect to the working machine 100A, and a control unit 40A for calibrating the measuring unit 20A. Therefore, the systematic error of the measuring unit 20A can be removed by calibration, and the working machine 100A can accurately grasp the position of the suspended load N by using the measurement data from which the systematic error has been removed.

[0077] Furthermore, according to the working machine 100A of Embodiment 2, the measurement unit 20A includes a first position detector 26 attached to the boom 106 and a second position detector 27 attached to the suspended load N or the spreader 107, and the control unit 40A calibrates the first position detector 26, the second position detector 27, or both by adding an offset to the position data. With such a configuration, it is possible to easily grasp the accurate position of the suspended load N with a small amount of measurement processing. Furthermore, the calibration process can be performed in a short time.

[0078] As described above, each embodiment of the present invention has been described. However, the present invention is not limited to the above embodiments. For example, in the above embodiment, a mobile crane, which is a crawler crane, is shown as the working machine. However, in addition to other mobile cranes such as a wheel crane and a truck crane, it is applicable to all cranes such as a harbor crane, a ceiling crane, a jib crane, a gantry crane, and a stationary crane such as an unloader. Further, the working machine may be any machine as long as it can lift a load, such as a shovel that lifts a load with a held rope.

[0079] Also, in the above embodiment, an example of shifting to the calibration mode based on the operation of an operator is shown. However, the control unit may determine whether the situation is suitable for the calibration mode, and when it is a suitable situation, give a notification recommending a shift to the calibration mode, or automatically shift to the calibration mode. In addition, details shown in the embodiments, such as the definition of the reference point and the rope length, can be appropriately changed without departing from the gist of the invention.

Explanation of Reference Numerals

[0080] 20, 20A Measurement unit 21 Imaging device 22 Boom angle measurement unit 23 Rope length measurement unit 26 First position detector 27 Second position detector 30, 30A Calculation unit 40, 40A Control unit 100, 100A Working machine 106 Boom 106a Point Sheave 107 Sling 108 Boom Overwind Preventer 109 Hook Overwind Preventer 112 Cab 114 Winch 116 Operating Section 117 Display Device 118 Notification Section N Lifting Load E Image P0 Reference Point

Claims

1. A working machine capable of suspending a load, a measuring unit for measuring the position of the suspended load with respect to the working machine, a control unit for calibrating the measuring unit, comprising, the measuring unit includes a boom angle measuring unit, a rope length measuring unit for measuring the payout length of the rope for suspending the load, or both, the control unit calibrates the boom angle measuring unit, the rope length measuring unit, or both, and calibrates the boom angle measuring unit when the boom reaches a predetermined angle, a working machine.

2. A working machine capable of suspending a load, a measuring unit for measuring the position of the suspended load with respect to the working machine, a control unit for calibrating the measuring unit, comprising, the measuring unit includes a first positioning device attached to the boom and a second positioning device attached to the suspended load or the lifting tackle, the control unit calibrates the first positioning device, the second positioning device, or both by adding an offset to the positioning data, a working machine.

3. the measuring unit includes a photographing device for photographing the suspended load, the control unit calibrates the mounting angle, mounting position, or both data of the photographing device, the working machine according to claim 1 or claim 2.

4. the measuring unit includes a photographing device for photographing the suspended load, the control unit calibrates the coordinates of the image of the photographing device, the working machine according to any one of claims 1 to 3.

5. the control unit calibrates the rope length measuring unit based on the operation of a hook overwind prevention device for preventing overwinding of the rope for suspending the load, the working machine according to claim 1.

6. The predetermined angle is an angle at which a boom overwind prevention device that prevents overwinding of a wire rope that raises and lowers the boom operates. The control unit calibrates the boom angle measurement unit based on the operation of the boom overwind prevention device. The work machine according to claim 1.

7. When receiving an input to shift to a calibration mode, calibrate the measurement unit. The work machine according to any one of claims 1 to 6.

Images