JP7626417B2 - Lifting device - Google Patents

Description

This disclosure relates to a lifting device.

A lifting device removes cargo loaded inside a floating object from the floating object. An example of a lifting device is an unloader device. Another example of a floating object is a ship. An unloader device is configured to derive a route for unloading cargo loaded onto a ship based on a coordinate system based on a predetermined position of the ship (for example, Patent Document 1).

JP 2019-131393 A

However, with the technology described in Patent Document 1, when a ship is rocked by waves, the coordinate system itself moves in accordance with the rocking of the ship. However, because the movement speed of the scraping unit that unloads the cargo is slow, there is a risk that the movement of the coordinate system will cause it to deviate from its route.

On the other hand, if the scraping unit is moved based on a coordinate system based on a specific position on the ground, it is not possible to take into account the movement of the ship due to tides, and there is a risk of the ship colliding with the scraping unit.

Therefore, there is a need to propose a coordinate system that can accommodate both the rocking of a ship due to waves and the movement of the ship due to tides.

In view of these problems, the present disclosure aims to provide a floating object monitoring device capable of deriving a coordinate system that reduces the effects of the swaying of floating objects due to tides and the movement of floating objects due to waves.

In order to solve the above problems, a lifting device according to one embodiment of the present disclosure includes a vertical transport mechanism for unloading cargo from a ship's hold, a ranging sensor provided on the vertical transport mechanism for periodically measuring the distance to an object on the ship, a position and attitude derivation unit that derives position and attitude information, which is information regarding the position or attitude of a floating object coordinate system based on a predetermined position on the ship, relative to a ground coordinate system based on a predetermined position on the ground, from measurement data from the ranging sensor, and a low-pass filter unit that applies a low-pass filter to the position and attitude information, wherein the low-pass filter unit applies a low-pass filter to the position and attitude information at a cutoff frequency at least between the frequency at which the ship sways due to waves and the frequency at which the ship moves due to tides .

The lifting device may be equipped with a path generating unit that generates a path for lifting the cargo along the position of the side wall of the hold based on the position and attitude information that has been subjected to a low-pass filter, and the vertical transport mechanism may lift the cargo along the path derived by the path generating unit.

The lifting device makes it possible to derive a coordinate system that reduces the effects of the swaying of floating objects caused by tides and the movement of floating objects caused by waves.

FIG. 2 is a diagram illustrating an outline of an unloader device. FIG. 2 is a diagram illustrating a configuration of an unloader device. FIG. 2 is a diagram illustrating a measurement range of a distance measuring sensor. FIG. 2 is a diagram illustrating a measurement range of a distance measuring sensor. FIG. 2 is a diagram illustrating a measurement range of a distance measuring sensor. FIG. 2 is a diagram illustrating a measurement range of a distance measuring sensor. FIG. 2 is a diagram illustrating the electrical configuration of the unloader device. 13 is a flowchart showing a process for creating a hold model and determining whether or not an approach has occurred. FIG. 4 is a diagram illustrating a coordinate system of the unloader device. FIG. 4 is a diagram illustrating a coordinate system of the unloader device. FIG. 2 is a diagram illustrating measurement points of a distance measuring sensor. FIG. 13 is a diagram showing how edge points are detected. FIG. 2 is a diagram illustrating a cutoff frequency of a low-pass filter. FIG. 13 is a diagram illustrating an automatic route.

One embodiment of the present disclosure will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific values shown in the embodiment are merely examples for ease of understanding, and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid duplicated explanations, and elements not directly related to the present disclosure are not illustrated.

Figure 1 is a diagram for explaining an overview of an unloader device 100. As shown in Figure 1, the unloader device 100, which is an example of a lifting device, is capable of traveling on a pair of rails 3 laid along a quay 2 in the direction in which the rails 3 extend. The unloader device 100 unloads cargo 6 loaded in a hold 5 of a ship 4 moored at the quay 2 to the outside. The cargo 6 is assumed to be bulk cargo, and one example is coal.

Figure 2 is a diagram explaining the configuration of the unloader device 100. Note that in Figure 2, the quay 2 and the ship 4 are shown in cross section. As shown in Figure 2, the unloader device 100 is composed of a running body 102, a rotating body 104, a boom 106, a top frame 108, an elevator 110, a scraping unit 112, and a boom conveyor 114. Note that the top frame 108, the elevator 110, and the scraping unit 112 function as a vertical transport mechanism that transports the cargo 6 out of the hold 5.

The running body 102 can run on the rails 3 by being driven by an actuator (not shown). A position sensor 116 is provided on the running body 102. The position sensor 116 is, for example, a rotary encoder. The position sensor 116 measures the position of the running body 102 on a horizontal plane relative to a predetermined origin position based on the number of rotations of the wheels of the running body 102.

The rotating body 104 is provided on the upper part of the running body 102 so as to be freely rotatable around a vertical axis. The rotating body 104 can be rotated relative to the running body 102 by being driven by an actuator (not shown).

The boom 106 is mounted on the upper part of the rotating body 104 so that the inclination angle can be changed. The boom 106 can change the inclination angle based on the rotating body 104 by being driven by an actuator (not shown).

The rotating body 104 is provided with a rotation angle sensor 118 and a tilt angle sensor 120. The rotation angle sensor 118 and the tilt angle sensor 120 are, for example, rotary encoders. The rotation angle sensor 118 measures the rotation angle of the rotating body 104 relative to the running body 102. The tilt angle sensor 120 measures the tilt angle of the boom 106 relative to the rotating body 104.

The top frame 108 is provided at the tip of the boom 106. The top frame 108 is provided with an actuator that rotates the elevator 110.

The elevator 110 is formed in a generally cylindrical shape. The elevator 110 is supported by the top frame 108 so as to be freely rotatable around a central axis. A rotation angle sensor 122 is provided on the top frame 108. The rotation angle sensor 122 is, for example, a rotary encoder. The rotation angle sensor 122 measures the rotation angle of the elevator 110 relative to the top frame 108.

The scraping unit 112 is provided at the lower end of the elevator 110. The scraping unit 112 rotates integrally with the elevator 110 as the elevator 110 rotates.

The scraping unit 112 is provided with multiple buckets 112a and a chain 112b. The multiple buckets 112a are arranged continuously on the chain 112b. The chain 112b is stretched across the scraping unit 112 and the inside of the elevator 110.

The scraping unit 112 is provided with a link mechanism (not shown). The link mechanism is movable to vary the length of the bottom of the scraping unit 112. This allows the scraping unit 112 to vary the number of buckets 112a that come into contact with the cargo 6 in the hold 5. The scraping unit 112 rotates the chain 112b, causing the buckets 112a at the bottom to scrape off the cargo 6 in the hold 5. The buckets 112a that have scraped off the cargo 6 then move to the top of the elevator 110 as the chain 112b rotates.

The boom conveyor 114 is provided below the boom 106. The boom conveyor 114 transports the cargo 6 that has been moved to the top of the elevator 110 by the bucket 112a to the outside.

The unloader device 100 thus configured moves in the extension direction of the rail 3 by the travelling body 102, and adjusts the relative positional relationship in the longitudinal direction with the ship 4. The unloader device 100 also rotates the boom 106, the top frame 108, the elevator 110 and the scraping unit 112 by the rotating body 104, and adjusts the relative positional relationship in the transverse direction with the ship 4. The unloader device 100 also moves the top frame 108, the elevator 110 and the scraping unit 112 in the vertical direction by the boom 106, and adjusts the relative positional relationship in the vertical direction with the ship 4. The unloader device 100 also rotates the elevator 110 and the scraping unit 112 by the top frame 108. This allows the unloader device 100 to move the scraping unit 112 to any position and angle.

Here, the ship 4 is provided with multiple holds 5. A hatch coaming 7 is provided at the top of each hold 5. The hatch coaming 7 has a wall surface of a certain height in the vertical direction. The hatch coaming 7 has a smaller opening area than the horizontal cross section near the center of the hold 5. In other words, the hold 5 has a shape in which the opening is narrowed by the hatch coaming 7. A hatch cover 8 for opening and closing the hatch coaming 7 is provided above the hatch coaming 7.

The unloader device 100 is provided with distance measuring sensors 130-136 as measuring instruments. The distance measuring sensors 130-136 are, for example, laser sensors capable of measuring distances, and VLP-16, VLP-32 manufactured by Velodyne, M8 manufactured by Quanery, etc. are applied. The distance measuring sensors 130-136 are provided with 16 laser irradiation units spaced apart along the axial direction, for example, on the side of a cylindrical main body. The laser irradiation units are provided on the main body so as to be rotatable 360 degrees. The laser irradiation units are each arranged so that the difference in the axial laser emission angle between adjacent laser irradiation units is 1 to 2.5 degrees apart. In other words, the distance measuring sensors 130-136 can irradiate a laser in a range of 360 degrees around the main body. The distance measuring sensors 130-136 can also emit a laser in a range of ±15 degrees based on a plane perpendicular to the axial direction of the main body. In addition, distance measurement sensors 130 to 136 have a receiving unit that receives the laser provided in the main body.

The distance measurement sensors 130-136 rotate the laser irradiation unit and irradiate a laser at a predetermined angle. The distance measurement sensors 130-136 each receive lasers irradiated (projected) from the multiple laser irradiating units and reflected by the object (measurement point) at a receiving unit. The distance measurement sensors 130-136 then derive the distance to the object based on the time between when the laser is irradiated and when it is received. In other words, the distance measurement sensors 130-136 use one laser irradiating unit to measure the distance to multiple measurement points on one measurement line. The distance measurement sensors 130-136 also use multiple laser irradiating units to measure the distance to multiple measurement points on multiple measurement lines.

Figures 3 and 4 are diagrams explaining the measurement ranges of the distance measuring sensors 130 to 132. Figure 3 is a diagram explaining the measurement ranges of the distance measuring sensors 130 to 132 when the unloader device 100 is viewed from above. Figure 4 is a diagram explaining the measurement ranges of the distance measuring sensors 130 to 132 when the unloader device 100 is viewed from the side. In Figures 3 and 4, the measurement ranges of the distance measuring sensors 130 to 132 are indicated by dashed lines.

The distance measuring sensors 130-132 are mainly used to detect the hatch coaming 7. As shown in Figures 3 and 4, the distance measuring sensors 130-132 are attached to the side of the top frame 108. Specifically, the distance measuring sensors 130-132 are arranged 120 degrees apart from each other in the circumferential direction with the central axis of the elevator 110 as the reference. The distance measuring sensors 130-132 are also arranged so that the central axis of the main body is aligned in the radial direction of the elevator 110. The upper vertical halves of the distance measuring sensors 130-132 are covered by a cover (not shown).

As shown in Figures 3 and 4, the distance measuring sensors 130 to 132 can therefore measure the distance to an object that is below the horizontal plane and within a range of ±15 degrees from the tangent line that touches the side of the top frame 108.

Figures 5 and 6 are diagrams explaining the measurement ranges of the distance measuring sensors 133 to 136. Figure 5 is a diagram explaining the measurement ranges of the distance measuring sensors 133 to 136 when the scraping unit 112 is viewed from above. Note that Figure 5 only illustrates the scraping unit 112 of the unloader device 100. Also, Figure 5 shows a horizontal cross section of the ship 4 at the same vertical position as the scraping unit 112. Figure 6 is a diagram explaining the measurement ranges of the distance measuring sensors 133 to 136 when the unloader device 100 is viewed from the side. In Figures 5 and 6, the measurement ranges of the distance measuring sensors 133 and 134 are indicated by dashed lines. Also, in Figures 5 and 6, the measurement ranges of the distance measuring sensors 135 and 136 are indicated by dashed lines.

The distance measuring sensors 133 to 136 are mainly used to detect the cargo 6 in the hold 5 and the walls (side walls and bottom) of the hold 5. The distance measuring sensor 133 is attached to the side 112c of the scraping unit 112 as shown in Figures 5 and 6. The distance measuring sensor 133 is positioned so that the central axis of the main body is perpendicular to the side 112c of the scraping unit 112. The distance measuring sensor 134 is attached to the side 112d of the scraping unit 112. The distance measuring sensor 134 is positioned so that the central axis of the main body is perpendicular to the side 112d of the scraping unit 112. Part of the vertical direction of the distance measuring sensors 133 and 134 is covered by a cover (not shown).

Therefore, the distance measuring sensors 133 and 134 can measure the distance to an object that exists in a range of ±15 degrees from a position parallel to the side 112c and side 112d of the scraping portion 112, which is a part of the upper side and the lower side of the side 112c and side 112d of the scraping portion 112 as a measurement direction. Note that the distance measuring sensors 133 and 134 of this embodiment are positioned on the plane on which the bottom of the scraping portion 112 is located so that they can measure a range at least equal to or greater than the maximum length of the bottom of the scraping portion 112.

The distance measurement sensor 135 is attached to the side surface 112c of the scraping portion 112. The distance measurement sensor 135 is positioned so that the central axis of the main body is perpendicular to the bottom surface of the scraping portion 112. The distance measurement sensor 136 is attached to the side surface 112d of the scraping portion 112. The distance measurement sensor 136 is positioned so that the central axis of the main body is perpendicular to the bottom surface of the scraping portion 112.

The distance measuring sensors 135 and 136 can therefore measure the distance to an object that is outside the scraping portion 112 and within a specified angle range based on a horizontal plane perpendicular to the sides 112c and 112d of the scraping portion 112 (or a plane perpendicular to the central axis of the main body).

When the distance measuring sensors 130-136 measure the distance to an object, they transmit measurement data indicating the distance to the object to the unloader control unit 140 (see Figure 7).

Figure 7 is a diagram explaining the electrical configuration of the unloader device 100. As shown in Figure 7, the unloader device 100 is provided with an unloader control unit 140, a memory unit 142, and a display unit 144.

The unloader control unit 140 is connected to the position sensor 116, the turning angle sensor 118, the tilt angle sensor 120, the turning angle sensor 122, the distance measuring sensors 130-136, the memory unit 142, and the display unit 144. The unloader control unit 140 is composed of a semiconductor integrated circuit including a CPU (central processing unit). The unloader control unit 140 reads out programs and parameters for operating the CPU itself from the ROM. The unloader control unit 140 then works together with the RAM as a work area and other electronic circuits to manage and control the entire unloader device 100.

The unloader control unit 140 also functions as a drive control unit 150, a measurement data acquisition unit 152, an edge detection unit 154, a position and orientation derivation unit 156, a low-pass filter unit 158, a path generation unit 160, and an automatic driving unit 162. The drive control unit 150 controls the driving of the unloader device 100. Details of the other functional units of the unloader control unit 140 will be described later.

The storage unit 142 is a storage medium such as a hard disk or non-volatile memory. The storage unit 142 stores a model of the hold 5, which will be described in detail later.

The display unit 144 is an LED display, an organic EL display, or the like. The display unit 144 displays an image in which a three-dimensional model of the unloader device 100 is placed relative to a three-dimensional model of the hold 5.

Figure 8 is a flowchart showing the flow of processing performed by the unloader control unit 140. As shown in Figure 8, when processing begins, the measurement data acquisition unit 152 first acquires measurement data of the measurement points measured by the distance sensors 130-136 at any time (S100). Note that the measurement data acquisition unit 152 periodically acquires measurement data from each of the distance sensors 130-136 at a frequency of 1 to 5 times per second from the time the scraping unit 112 starts scraping the cargo 6 in the hold 5 until all of the cargo 6 has been scraped (e.g., 10 hours).

Figures 9 and 10 are diagrams explaining the coordinate system of the unloader device 100. Figure 9 is a view of the unloader device 100 seen from above. Figure 10 is a view of the unloader device 100 seen from the side. Here, the unloader device 100 has three coordinate systems, namely, a ground coordinate system 300, a scraping section coordinate system 310, and a hatch combing coordinate system 320.

As shown in Figures 9 and 10, the ground coordinate system 300 has its origin at a predetermined position previously set on the quay 2 (ground), for example the initial position of the unloader device 100. In the ground coordinate system 300, the Xa axis direction is a direction perpendicular to the extension direction of the rail 3 and the vertical direction. In the ground coordinate system 300, the Ya axis direction is the extension direction of the rail 3. In the ground coordinate system 300, the Za axis direction is the vertical direction.

The scraping unit coordinate system 310 is on the central axis of the elevator 110, and has its origin at the lower end of the top frame 108 in the vertical direction. In the scraping unit coordinate system 310, the direction from the origin toward the center of the tip 112e of the scraping unit 112 is the Xb axis direction. In the scraping unit coordinate system 310, the extension direction of the elevator 110 is the Zb axis direction. In the scraping unit coordinate system 310, the direction perpendicular to the Xb axis direction and the Zb axis direction is the Ya axis direction.

The hatch coaming coordinate system 320 is the center position of the stern wall surface of the hatch coaming 7 of the ship 4, and has the upper end of the hatch coaming 7 as the origin (a specified position of the ship 4). The hatch coaming coordinate system 320 has the Xc axis direction as the longitudinal direction of the ship 4, that is, the extension direction of the hatch coaming 7 along the ship 4. The hatch coaming coordinate system 320 has the Yc axis direction as the short side direction (width direction) of the ship 4. The hatch coaming coordinate system 320 has the Zc axis direction as the upward direction perpendicular to the upper end surface of the hatch coaming 7.

なお、位置姿勢Ｔは、位置および姿勢に関する情報、すなわち、位置姿勢情報であり、原点の変位および回転（ロール、ピッチ、ヨー）を４×４の行列で表した同次元変換行列である。つまり、位置姿勢Ｔは、一般的にＸ軸、Ｙ軸、Ｚ軸で表される３軸に加え、ロール、ピッチ、ヨーを加えた６軸で表されている。なお、位置姿勢Ｔは、位置または姿勢に関する情報であってもよい。また、（１）式において、ＧＲは地上座標系３００を示し、ＢＥは掻取部座標系３１０を示し、ＨＣはハッチコーミング座標系３２０を示す。 Then, each time the measurement data acquisition unit 152 acquires measurement data from the distance measurement sensors 130 to 136, the position and orientation derivation unit 156 derives the position and orientation ^GR T _HC of the hatch combing coordinate system 320 viewed from the ground coordinate system 300 using equation (1) (S102).

The position and attitude T is information on the position and attitude, that is, position and attitude information, and is a homogeneous transformation matrix in which the displacement and rotation (roll, pitch, yaw) of the origin are expressed as a 4×4 matrix. That is, the position and attitude T is expressed by six axes, which are the three axes generally represented by the X-axis, Y-axis, and Z-axis, plus the roll, pitch, and yaw. The position and attitude T may be information on the position or attitude. In addition, in formula (1), GR indicates the ground coordinate system 300, BE indicates the scraping unit coordinate system 310, and HC indicates the hatch combing coordinate system 320.

Moreover, the position and orientation ^GR T _BE indicates the position and orientation of the scraping unit coordinate system 310 as viewed from the ground coordinate system 300. The position and orientation ^HC T _BE indicates the position and orientation of the scraping unit coordinate system 310 as viewed from the hatch combing coordinate system 320.

Here, the position and rotation of the origin of the scraping unit coordinate system 310 as viewed from the ground coordinate system 300 can be geometrically derived based on the shape of the unloader apparatus 100, the movement of the unloader apparatus 100, and the rotation of the scraping unit 112. Therefore, the position and orientation derivation unit 156 derives the position and orientation ^GR T _BE based on the shape of the unloader apparatus 100, the movement of the unloader apparatus 100, and the rotation of the scraping unit 112.

In addition, since the distance measuring sensors 130 to 132 are attached to the top frame 108, their positions in the scraping unit coordinate system 310 are known in advance. Therefore, the edge detection unit 154 detects the upper edge of the hatch combing 7 based on the measurement data of the measurement points measured by the distance measuring sensors 130 to 132. Then, the position and orientation derivation unit 156 derives the position and orientation ^HC T _BE based on the detected upper edge of the hatch combing 7.

Specifically, first, the edge detection unit 154 derives the three-dimensional position of the measurement point in the scraping unit coordinate system 310 based on the positions of the distance measurement sensors 130-132 and the distance and direction to the measurement point measured by the distance measurement sensors 130-132.

Figure 11 is a diagram explaining the measurement points of the distance measuring sensors 130-132. In Figure 11, the measurement range of the distance measuring sensors 130-132 on the hatch combing 7 is indicated by a thick line. As shown in Figure 11, the distance measuring sensors 130-132 are below the horizontal plane and measure the distance to an object that exists within a range of ± a specified angle from the distance measuring sensors 130-132 using a plane that is tangent to the top frame 108 as a reference.

Therefore, the distance measuring sensors 130-132 use the vertically downward point of the distance measuring sensors 130-132 (the center of rotation of the elevator 110) as a reference point, and the measurement range is the edge of the hatch combing 7, which differs between the front and rear sides. Note that the front side refers to the measurement range measured in the first half of a single measurement. The rear side refers to the measurement range measured in the second half of a single measurement.

Therefore, the measurement points measured by the distance measuring sensors 130 to 132 are divided into two, the front side and the rear side, based on the vertically downward direction of the distance measuring sensors 130 to 132.

Figure 12 is a diagram showing how edge points are detected. In Figure 12, measurement points are indicated by black circles. Figure 12 illustrates measurement points measured by a laser irradiated by one of the laser irradiation sections of distance measuring sensors 130-132.

The edge detection unit 154 performs the following processing for each group of measurement points (for both the front and rear sides) of one measurement line irradiated and measured by one laser irradiation unit. The edge detection unit 154 derives the vector (direction) of each measurement point irradiated and measured by one laser irradiation unit. Note that the vector of a measurement point is derived by deriving the direction (vector) of the next measurement point measured relative to one measurement point among the measurement points measured consecutively as the vector of one measurement point.

The edge detection unit 154 then extracts measurement points whose vectors are vertical. This is because the wall surface (side surface) of the hatch combing 7 measured by the distance measurement sensors 130 to 132 extends in a roughly vertical direction, so if a measurement point is on the wall surface of the hatch combing 7, the vector of the measurement point will be vertical.

Then, when there are multiple consecutively extracted measurement points among the extracted measurement points, the edge detection unit 154 extracts the uppermost point in the vertical direction. This is because, in order to detect the upper edge of the hatch combing 7, the uppermost point in the group of consecutively measured measurement points may be the upper edge of the hatch combing 7.

Then, the edge detection unit 154 extracts the measurement point that is closest to the origin in the Xb-axis direction and the Yb-axis direction in the scraping unit coordinate system 310 from among the extracted measurement points. In other words, the edge detection unit 154 extracts the measurement point that is closest to the central axis of the elevator 110. This is because the hatch coaming 7 is located closest to the elevator 110 among the various structures of the ship 4.

Then, the edge detection unit 154 re-extracts measurement points that exist within a predetermined range (e.g., a range of several tens of centimeters) in the Xb-axis direction and Yb-axis direction in the scraping unit coordinate system 310 from the extracted measurement points. Here, the measurement points on the hatch combing 7 are extracted.

Then, the edge detection unit 154 extracts the re-extracted measurement point, that is, the uppermost measurement point in the vertical direction among the measurement points on the hatch combing 7, as an edge point of the hatch combing 7.

The edge detection unit 154 extracts front and rear edge points for each group of measurement points irradiated and measured by one of the laser irradiation units of the distance measurement sensors 130 to 132.

When all edge points have been extracted, the edge detection unit 154 detects straight lines of the edges of the hatch combing 7. Specifically, the edge detection unit 154 groups the edge points extracted on the front side of the distance measurement sensor 130 into one group. Similarly, the edge detection unit 154 groups the edge points extracted on the rear side of the distance measurement sensor 130 into one group. Furthermore, the edge detection unit 154 groups the edge points extracted on the front and rear sides of the distance measurement sensors 131 and 132 into groups.

Here, as shown in FIG. 11, two straight lines of the upper edge of the hatch combing 7 are measured on the front and rear sides of the distance measuring sensors 130-132, respectively, and if the corners of the hatch combing 7 are included, then two straight lines will be measured.

The edge detection unit 154 then derives, for each group, the line segments between the extracted edge points that have the most similar line segments as a candidate vector. The edge detection unit 154 then extracts edge points that exist within a preset range for the candidate vector. The edge detection unit 154 then recalculates the straight line using the extracted edge points.

Next, the edge detection unit 154 repeats the above process using the edge points that were not extracted. However, if the number of extracted edge points is less than a preset threshold, no straight lines are derived. This makes it possible to derive straight lines for two edges even when the corners of the hatch combing 7 are included.

The edge detection unit 154 derives the edge straight lines by repeating the above process for each group. In this way, a maximum of two edge straight lines are detected at one location, resulting in a maximum of 12 straight lines being detected.

The edge detection unit 154 then derives the angles between the detected straight lines. If the angles between the straight lines are equal to or smaller than a predetermined threshold, the edge detection unit 154 merges the straight lines as being the same straight line. Specifically, the edge detection unit 154 re-derives straight lines by least squares approximation using edge points that constitute straight lines whose angles are equal to or smaller than a predetermined threshold.

Next, the edge detection unit 154 derives edge information from the straight lines of the detected edges, including the three-dimensional direction vector of each side, the three-dimensional center of gravity coordinates of each side, the length of each side, and the coordinates of the endpoints of each side.

Next, the position and orientation derivation unit 156 derives the position and orientation HC T BE based on the three-dimensional model information of the hatch combing 7 stored in the storage unit 142 and the edge side information (detection result) expressed in the _scraping unit coordinate system 310. Note that the three-dimensional model information of the hatch combing 7 indicates a ^three -dimensional model of the hatch combing 7 represented by the hatch combing coordinate system 320.

The position and orientation derivation unit 156 performs rough correction by rotating the orientation of the detected straight line of the edge of the hatch combing 7 by the rotation angle of the boom 106. In addition, the position and orientation derivation unit 156 associates the straight line of the detected edge of the hatch combing 7 with the upper edge of the hatch combing 7 in the 3D model information by matching the straight lines with the closest edge orientation.

Then, the position and orientation derivation unit 156 uses, for example, the sum of squares of the differences in distance between edge points constituting the straight line of the edge and the upper side of the hatch combing 7 based on the three-dimensional model information as an evaluation function, and obtains the position and orientation ^HC T _{BE that minimizes the evaluation function, for example, by the LM method. Specifically, the position and orientation HC T BE} is obtained so that the sum of the distances between the edge points constituting the straight line of the edge and the upper side of the hatch combing 7 based on the three-dimensional model information, or the area of the curved surface formed by the straight line of the edge and the upper side of the hatch combing _{7 based on the three-dimensional model information, is minimized. Note that the method for obtaining the position and orientation HC T BE} ^{is not} _limited to the LM method, and other methods such as the steepest descent method and Newton's method may be used.

Then, the position and orientation derivation unit 156 derives the position and orientation ^GR T _HC using the equation (1) based on the derived position and orientation ^GR T _BE and position and orientation ^HC T _BE . The position and orientation ^GR T _HC is derived every time measurement data is acquired by the distance measurement sensors 130 to 132.

When the position and orientation ^GR T _HC is derived by the position and orientation derivation unit 156, the low-pass filter unit 158 applies a low-pass filter to the position and orientation ^GR T _HC (S104).

A low-pass filter is a first-order lag filter with a predetermined cutoff frequency. However, the low-pass filter is not limited to a first-order lag filter, and may be, for example, a second-order lag filter. Any type of filter may be used as a low-pass filter as long as it can cut (attenuate) frequency components below the cutoff frequency.

Figure 13 is a diagram explaining the cutoff frequency of a low-pass filter. As shown in Figure 13, the measurement data from the distance sensors 130 to 132 includes measurement noise with a time constant of, for example, 0.5 seconds. The rocking of the ship 4 due to the influence of waves has a time constant of, for example, 5 seconds. The movement of the ship 4 due to the tides has a time constant of, for example, several hours to half a day.

The cutoff frequency of the low-pass filter is set to a value that attenuates the effects of the rocking of the ship 4 caused by waves and the effects of measurement noise. On the other hand, the cutoff frequency of the low-pass filter is set to a value that does not attenuate the effects of the movement of the ship 4 caused by the tides.

In other words, the time constant of the low-pass filter is set between the time constant of the rocking of the ship 4 due to waves and the time constant of the movement of the ship 4 due to tides. For example, the time constant of the low-pass filter is set between 10 seconds and 1 minute. In other words, the cutoff frequency of the low-pass filter is set between the frequency at which the ship 4 rocks due to waves and the frequency at which the ship 4 moves due to tides.

When the position and orientation ^GR T _HC is derived by the position and orientation derivation unit 156, the low-pass filter unit 158 applies a low-pass filter to the position and orientation ^GR T _HC , which attenuates frequencies equal to or higher than a cutoff frequency. In other words, the position and orientation LPF( ^GR T _HC ) that has been subjected to the low-pass filter is information obtained by subjecting the position and orientation ^GR T _HC to processing by the low-pass filter.

As a result, the position and attitude LPF ( ^GR _THC ) cuts (attenuates) the frequency components of the ship 4 rocking due to waves and the frequency components of measurement noise. Moreover, the position and attitude LPF ( ^GR _THC ) does not cut the frequency components of the ship 4 moving due to the tides, and the frequency components remain.

Next, we will explain the processing of the route generation unit 160 and automatic driving unit 162 of the unloader device 100.

Figure 14 is a diagram explaining the automatic route. Here, when the unloader device 100 scrapes off the cargo 6, there are roughly three processes. If the cargo 6 in the hold 5 has never been scraped off, the cargo 6 is piled up in the hold 5 in a mountain shape. Therefore, the first process is to flatten the cargo 6 in the hold 5. The first process is performed by an operator manually operating the unloader device 100.

After that, when the surface of the cargo 6 loaded in the hold 5 becomes almost flat, in the second step, as shown in FIG. 14, the scraping unit 112 is moved around the wall of the hold 5 several times, and then moved once around the center. This second step can be automated because the path along which the scraping unit 112 moves is simple and the amount of cargo 6 scraped is stable.

After that, when the cargo 6 in the hold 5 becomes small, the remaining cargo 6 is scraped off by the scraping unit 112 in the third step. In this third step, it is necessary to move the scraping unit 112 to the position of the cargo 6 remaining in the hold 5. Also, in the third step, it is necessary to move the scraping unit 112 near the bottom of the hold 5. Therefore, the third step is performed by an operator manually operating the unloader device 100.

In this way, of the three steps involved in scraping off the cargo 6 using the unloader device 100, the second step can be automated by the unloader device 100.

The path generation unit 160 reads out the three-dimensional model of the hold 5 stored in the memory unit 142. The three-dimensional model of the hold 5 is represented by the hatch coaming coordinate system 320.

Then, the path generating unit 160 converts the coordinate system of the three-dimensional model of the hold 5 from the hatch coaming coordinate system 320 into a coordinate system using the position and attitude LPF ( ^GR _THC ).

Then, the path generation unit 160 uses the three-dimensional model of the hold 5 with the transformed coordinate system to create an automatic path for translating the scraping unit 112 along the side wall of the hold 5, as shown in FIG. 14 (S106).

The automatic driving unit 162 moves the scraping unit 112 along the path created by the path generating unit 160 (S108). At this time, the coordinate system of the three-dimensional model of the hold 5 is changed using the position and attitude LPF ( ^GR _THC ) that has been subjected to a low-pass filter. This removes the influence of the rocking of the ship 4 caused by waves, so that even if the moving speed of the scraping unit 112 is slow, the scraping unit 112 can move (follow) along the created path without being influenced by the rocking of the ship 4 caused by waves.

In addition, although the frequency components that cause the ship 4 to move due to the tides are not cut off, the movement speed of the scraping unit 112 is sufficient to accommodate the movement of the ship 4 due to the tides.

Thus, the unloader apparatus 100 can derive a coordinate system that reduces the effects of the swaying of the ship 4 due to tides and the movement of the ship 4 due to waves, using the position and attitude LPF ( ^GR _THC ). The unloader apparatus 100 can also move the scraping unit 112 along the created automatic route. The unloader apparatus 100 can also reduce the effects of measurement noise.

In addition, since the position and attitude LPF ( ^GR _THC ) represents the three axes of roll, pitch, and yaw, the behavior of the ship 4 can be represented in a manner that makes it easy to understand.

Although the embodiments have been described above with reference to the attached drawings, it goes without saying that the present disclosure is not limited to such embodiments. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope.

For example, in the above embodiment, a ship 4 is used as an example of a floating object. However, the floating object is not limited to a ship 4 as long as it floats in a liquid (e.g., the sea).

Furthermore, the method of deriving the position and attitude ^GR T _HC in the above embodiment is merely an example. The method of deriving the position and attitude ^GR T _HC may be another method. For example, a GPS may be attached to the ship 4, and the position and attitude ^GR T _HC may be derived based on information from the GPS.

In the above embodiment, the automatic driving unit 162 moves the scraping unit 112 along the automatic path created by the path generation unit 160. However, the automatic path created by the path generation unit 160 may be displayed on the display unit 144, and the worker may move the scraping unit 112 while checking the automatic path.

In the above embodiment, the unloader device 100 has been described as an example of a lifting device. However, the lifting device may be a continuous unloader (bucket type, belt type, vertical screw conveyor type, etc.), a pneumatic unloader, etc.

This disclosure can be used in lifting devices.

100 Unloader device (unloading device)
130 Distance sensor (measuring instrument)
131 Distance sensor (measuring instrument)
131 Distance sensor (measuring instrument)
156 Position and orientation derivation unit 158 Low-pass filter unit 160 Path generation unit

Claims (2)

a vertical transport mechanism for unloading cargo from a hold of the ship;
a distance sensor provided on the vertical transport mechanism for periodically measuring a distance to an object on the vessel;
a position and attitude derivation unit that derives, from the measurement data from the distance measuring sensor, position and attitude information that is information regarding a position or attitude of a floating object coordinate system based on a predetermined position on the ship with respect to a ground coordinate system based on a predetermined position on the ground;
a low-pass filter unit that applies a low-pass filter to the position and orientation information;
Equipped with
the low-pass filter unit applies the low-pass filter to the position and attitude information at a cutoff frequency between a frequency at which the ship is swayed by waves and a frequency at which the ship moves by tides;
Lifting equipment. the lifting device includes a path generating unit that generates a path for lifting the cargo along a position of a side wall of the hold based on the position and attitude information that has been subjected to the low-pass filter,
The vertical transport mechanism unloads the cargo along the route derived by the route generation unit.
2. The lifting device of claim 1 .

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