JP4862383B2 - Cooperative transport method and cooperative transport apparatus - Google Patents

Description

The present invention relates to a coordinated conveyance method and a coordinated conveyance device for conveying heavy objects, long objects, and the like by a plurality of mobile crane apparatuses .

In recent years, there has been an increasing demand for production automation at construction sites, factories, warehouses, etc., and objects are transferred by automated guided vehicles, overhead cranes, and robots. However, in order to transport various objects, the robot's ability is limited, and large objects that exceed the robot's transportation capacity cannot be transported by the robot, and another new robot must be introduced. .
On the other hand, by introducing multiple small robots and transporting them in a coordinated manner like a human being, it is possible to transport objects that could not be transported by a single robot. Accordingly, it is possible to respond flexibly by changing the number of robots accordingly, and this is expected to improve the efficiency of work in the field.

Conventionally, this type of cooperative transport is mainly realized by a mobile robot equipped with a manipulator and a forklift.
For example, in Non-Patent Document 1 below, one robot as a leader is selected from a plurality of robots, and the remaining robot called a follower estimates the operation of the reader by some sensor, and transports the transport object to the destination in a coordinated manner. One proposal has been made on how to do this.
Also, in the following Patent Document 1, in the coordinated transport of a two-wheel independent drive type robot, the transport wheel is transported so as to be rotatable about its vertical axis at a position separated from the midpoint of the two wheels of the drive wheel in the traveling direction of the wheel. One proposal has been made for a method of supporting an object and performing coordinated transport by controlling the moving speed of the support point and the internal force applied to the transported object.

Kazuhiro Komine, Tomohiro Ozumi, Akihiko Chiba: Journal of the Robotics Society of Japan, vol. 16, no. 1, pp. 87-95, 1998 JP 2000-42958 A

As described above, the cooperative transport according to the prior art is realized mainly by a mobile robot including a manipulator and a forklift.
However, when it is limited to the transportation work, there is a problem that transportation by a manipulator or forklift has a high equipment cost per transportation weight and is not suitable for transportation of heavy objects.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a coordinated conveyance method and a coordinated conveyance device that can reduce equipment cost per conveyance weight and are advantageous for conveyance of heavy objects.

In order to solve the above problems, the cooperative transport method and the cooperative transport apparatus of the present invention employ the following means.
That is, according to the present invention , a plurality of mobile crane devices that are configured to be movable and include a crane that can suspend a transported object are used, and the transported object is suspended with a wire by the plurality of mobile crane devices. While transporting to the destination
One of the plurality of mobile crane devices is a leader to which an operation command to the destination is given, and the other remaining mobile crane devices are followers that move while estimating the position and orientation of the reader, And an imaging device that images at least one of the wires of the crane in a state where the transported object is suspended in the follower,
An operation command to the destination is given to the reader, and the position of the transport object, the wire, or these predetermined parts in the follower coordinate system is detected from the image of the imaging device, and the detected position and the change in the position are detected. Based on the estimated position and orientation of the reader based on the estimated position and orientation of the reader, so that the relative position of the reader and the follower is held at the relative position of the reader and the follower in an initial state, There is provided a cooperative transport method for controlling the follower.

As described above, since the transport object is cooperatively transported by a plurality of mobile crane devices , the equipment cost per transport weight can be reduced compared to the conventional transport using a manipulator or the like, which is advantageous for transporting heavy objects. is there.

Note that, in the "operation command" is not only the operation command by the computer, the operation command by the human driver or through the communication unit operation (remote control) are also included.

Thus, when an operation command to the destination is given to the reader and the operation is performed, the follower estimates the operation of the reader from the change in the position of the transport object, the wire, or a predetermined portion thereof, and the target position of the reader is determined from the operation of the reader. Therefore, it is not necessary to give an operation command to a plurality of mobile crane devices , and communication between the leader and the follower and between the followers is not necessary.
For this reason, it is only necessary to change the operation command of the reader when changing the destination, compared to the case where the operation command (target trajectory) is given to all the mobile crane devices, and no change is necessary for the follower control. There are advantages. Moreover, even if the mobile crane apparatus used as a leader is operated by a human operation (operation or remote control), cooperative transport is possible.

The follower operates so as to hold the relative position between the leader and the follower at the relative position between the leader and the follower in the initial state, so that each mobile crane device may collide close to the transported object while transporting the moving object. The mobile crane device can be reliably transported to the destination without the distance between the mobile crane devices being too far and falling due to the weight of the transported object.

Further, in the cooperative transport method according to the embodiment of the present invention , the swing of the transport object due to the operation of the mobile crane device is estimated from the speed of a follower, and the transport is performed for the detected position based on the estimated value. It is characterized by correcting an error caused by an object shake.

  As described above, since the error due to the shake of the transported object is corrected for the position detected based on the image captured by the image capturing apparatus, the operation (position, orientation) of the reader can be accurately estimated. For this reason, each follower can convey a conveyance object stably, keeping a relative position with a leader constant.

In addition, according to the present invention , the mobile object is composed of a plurality of mobile crane devices that are configured to be movable and include a crane that can suspend a transport object, and the transport object is co-suspended with a wire by the plurality of mobile crane devices. A coordinated transport device that transports to a destination while
One of the plurality of mobile crane devices is a leader to which an operation command to a destination is given, and the other mobile crane devices are followers that move while estimating the position and orientation of the leader. Yes,
The follower
An imaging device for imaging at least one of the wires of the transported object and conveying the state of hanging objects crane,
Conveying the object from the image of the imaging device in the coordinate system of the follower, and the wire or the position detection unit for detecting the position of a given site,
An operation estimation unit that estimates the position and orientation of the reader based on the detected position and a change in the position ;
An operation control unit that controls the follower based on the estimated position and orientation of the reader so that the relative position of the reader and the follower is held at the relative position of the reader and the follower in an initial state. ,
There is provided a cooperative transport apparatus characterized by the above .

Further, in the cooperative transport device according to the embodiment of the present invention, the follower estimates the swing of the transport object due to the operation of the mobile crane device from the follower speed , and detects the detection based on the estimated value. It further has an error correcting unit that corrects an error caused by a shake of the conveyed object with respect to the position.

  With the above-described cooperative transport apparatus, the cooperative transport method of the present invention can be implemented.

  According to the present invention, it is possible to reduce the equipment cost per transported weight and to obtain an excellent effect that it is advantageous for transporting heavy objects.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is a diagram showing an overview of a cooperative transport apparatus 10 according to an embodiment of the present invention.
As shown in FIG. 1, the cooperative transport device 10 includes a plurality of mobile crane devices 10 </ b> A that include a crane 4 that can suspend a transport object 1 and that is configured to be movable. Each mobile crane apparatus 10A can move forward and backward, and turn in the left and right directions to move freely on the ground, and while suspending the transport object 1 with these multiple mobile crane apparatuses 10A. Carry to the destination in a coordinated manner.
Mobile crane device 10A in this embodiment is a two, the weight of the transport object 1, the size, and the like conveying capacity of the mobile crane device 10A, may be coordinated transport in three or more.

One of the plurality of mobile crane apparatuses 10A is a leader to which an operation command to the destination is given, and the other remaining mobile crane apparatus 10A is a follower that moves while estimating the operation of the reader. In the present embodiment, the left mobile crane apparatus 10 </ b> A in FIG. 1 is the leader 11, and the right mobile crane apparatus 10 </ b> A is the follower 12.

10 A of mobile crane apparatuses are provided with the mobile trolley 3 which can drive | work the ground, and the crane 4 provided on the mobile trolley 3 with both the leader 11 and the follower 12. FIG. The crane 4 includes a support column 5 and a wire 6 attached to the support column 5, and the transported object 1 is suspended by a hook or the like provided at the tip of the wire 6. In the present embodiment, the wire 11 of the crane 4 of the leader 11 and the follower 12 are both the same length, and the mounting height of the upper end portion is also set to be the same.
Here, the distance between the upper ends of the wires 6 of the leader 11 and the follower 12 when the leader 11 and the follower 12 are arranged in parallel at the same position in the front-rear direction is defined as an inter-vehicle distance d, and this state is an initial state.

  The reader 11 operates by being given an operation command to the destination. This operation command is pre-programmed, receives an operation command from another control device via a communication means, or is human. Or an operation command by operation (remote control) via communication means.

The mobile crane apparatus 10 </ b> A that is the follower 12 further includes an imaging apparatus 8 (for example, a video camera) that images the transport object 1 and the wire 6 of the crane 4 from above. Further, a beam 9 for supporting the imaging device 8 is provided on the column 5 of the crane 4. The imaging device 8 images at least one of the transport object 1 and the wire 6 of the crane 4 in a state in which the transport object 1 is suspended from above, and a specific portion of these is detected from a position detection unit 21 described later. The position is to be detected in (see FIG. 3).
In the present embodiment, a marker 13 that can be identified by the imaging device 8 is installed at a connection point between the transport object 1 and the wire 6 of the crane 4 of the follower 12, and the marker 13 is set as a specific part that is a position detection target. Yes.
Note that the position of the specific part may be detected by image processing such as pattern matching using the entire or part of the shape of the transport object 1 as a feature point without installing the marker 13. Moreover, the marker 13 may be installed in parts other than the connection point of the conveyance object 1 and the wire 6 of the crane 4 of the follower 12.

FIG. 2 is a view of the reader 11, the follower 12, and the transported object 1 as viewed from above, and shows a state in which the transport object 1 is moved by giving an operation command to the reader 11 to operate the reader 11. . A range surrounded by a frame 15 is a range of an image captured by the imaging device 8. The broken line indicates the reader 11 and its wire 6 in the initial state, the conveyed object 1, and the wire 6 of the follower 12.
In this way, the reader 11 operates and the relative position between the reader 11 and the follower 12 changes from the initial state, so that the position of the transport object 1 and the wire 6 is displaced, and the position of the marker 13 is also displaced. Here, the position of the marker 13 when the position of the upper end of the wire 6 of the follower 12 is defined as the zero point of the coordinate system is expressed by l _v and φ _v .
In addition, since it is necessary to track the positional displacement of the marker 13 by the imaging device 8 in this way, the imaging is performed so that the marker 13 can be accommodated on the captured image even if the position of the marker 13 is moved in accordance with the operation of the reader 11. The angle of view and installation height of the device 8 are set.

As shown in FIG. 1, the mobile crane apparatus 10 </ b> A that is the follower 12 includes a processing unit 20 that performs various types of information processing, calculation, and control.
FIG. 3 is a diagram illustrating a configuration of the processing unit 20 of the mobile crane apparatus 10 </ b> A that is the follower 12. The processing unit 20 includes a position detection unit 21, an error correction unit 22, a motion estimation unit 23, and a motion control unit 24.
The position detection unit 21 receives an image signal from the imaging device 8, detects the position of the transport object 1, the wire 6, or these predetermined parts in the coordinate system of the follower 12 and generates position information thereof. In the present embodiment, the position of the marker 13 is detected from the image of the imaging device 8.

The error correction unit 22 estimates the shake of the transport object 1 due to the operation of the mobile crane device 10A (the reader 11 and the follower 12), and based on this estimated value, the error due to the shake of the transport object 1 at the detected position. To correct. The detected position information of the marker 13 includes an error due to the shake of the transport object 1. As a result, when the transport object 1 is shaken even though the reader 11 is stopped, the follower 12 detects the shake of the transport object 1 and operates accordingly. Therefore, the error correction unit 22 corrects an error due to the shake of the conveyed object 1.

  The motion estimation unit 23 estimates the motion of the reader 11 based on the position information of the transport object 1. The position information of the transport object 1 is position information in which an error due to the shake of the transport object 1 is corrected by the error correction unit 22. Specifically, since the two wires 6 projected from the top have a direction and a length that are symmetric with respect to the conveyed object 1, the coordinates of the follower 12 are determined from the position of the conveyed object 1 detected based on the image of the imaging device 8. The position and orientation of the reader 11 in the system can be estimated.

  The operation control unit 24 controls the operation of the follower 12 based on the estimated operation of the reader 11. Specifically, the operation control unit 24 maintains the relative position between the reader 11 and the follower 12 at the relative position between the reader 11 and the follower 12 in the initial state based on the estimated operation of the reader 11. To control the operation.

  Such a processing unit 20 can be constituted by, for example, a microcomputer, and the position detection unit 21, the error correction unit 22, the motion estimation unit 23, and the motion control unit 24 described above have functions of such a microcomputer. Can be realized as part.

Next, a cooperative transport method realized by the operation of the cooperative transport apparatus 10 according to the present embodiment will be described.
FIG. 4 is a diagram illustrating a positional relationship of the leader 11, the follower 12, and the transported object 1 when viewed from above when moving forward while turning right as an example of the operation of the reader 11.
When an operation command is given to the reader 11 from the initial state, the relative position between the reader 11 and the follower 12 changes, so that the position of the transport object 1 and the wire 6 is displaced, and the position of the marker 13 is also displaced. . The follower 12 images the movement of the marker 13 by the imaging device 8, and the position detector 21 detects the position of the marker 13 in the coordinate system of the follower 12.

Since the position information of the marker 13 detected by the position detection unit 21 includes an error due to the shake of the conveyed object 1, the error correction unit 22 corrects the error by the following method.
The shake of the transport object 1 depends on the acceleration of the reader 11 and the follower 12, and the error correction unit 22 estimates the shake of the transport object 1 from the following formula (Equation 1) from the speed of the follower 12.

  Here, l is the length of the wire 6 and g is the gravitational acceleration. Based on the obtained deflection angle, the position information of the detected marker 13 is corrected from the following equations (Equation 2 and Equation 3).

  If there is no shake, the two wires 6 are symmetrical to the conveyed object 1 as shown in FIG. 4, so the motion estimation unit 23 geometrically estimates the position and orientation of the reader 11 from the position information of the marker 13. The operation control unit 24 determines the target position and orientation for maintaining the relative positions of the reader 11 and the follower 12 in the initial state using the following equations (Equations 4 to 6).

Here, d ₀ is the distance between the connection points of the wire 6 of the reader 11 and the follower 12 and the transport object 1 (size of the transport object 1) (see FIG. 1).
The speed of the follower 12 is obtained from the following equation (Equation 7) from the obtained target position and orientation.

Here, K _v and K _ω are positive constants. Further, s and t are coefficients related to the operation of the reader 11 (straight, right turn, left turn), and are obtained according to the conditions of the following equations (Equations 8 and 9).

The sign of the translation speed and rotation speed of the follower 12 is determined for the operation of the reader 11 (straight, right turn, left turn) according to the conditions of the above formulas (Formula 8 and Formula 9).
As described above, when the operation is performed by giving the operation command to the destination to the reader 11, the follower 12 estimates the operation of the reader 11 from the change in the position of the marker 13, and determines the target position of the follower 12 from the operation of the reader 11. Therefore, the transport object 1 can be cooperatively transported to the destination by the reader 11 and the follower 12.

Next, a simulation result when the reader 11 travels in the right turn and the left turn will be described.
FIG. 5 shows a case where the trajectory of the reader 11 is turned right, and FIG. 6 shows a case where the trajectory of the reader 11 is turned left. The speed of the reader 11 was a quintic function with respect to time, the maximum speed was 0.5 m / s, and the initial distance between the cars was d = 0.8 m. 5 and 6, the left side is a case where the position information is not corrected, and the right side is a case where the shake of the transport object 1 is estimated and the position information is corrected.

  From the simulation result, when the follower 12 estimates the operation of the reader 11 only by the position information of the transport object 1, the follower 12 does not detect the shake of the transport object 1 even though the reader 11 is stopped. Will continue to work. Moreover, the movement of the conveyed object 1 is promoted by the operation, and the operation of the follower 12 is diverged. On the other hand, when the shake is estimated and the detected value is corrected, it is understood that the operation is performed so as to hold the initial relative position well with respect to the trajectory of the reader 11.

Next, operations and effects of the cooperative transport method and the cooperative transport apparatus 10 according to the present invention will be described.
According to the present invention, since the transport object 1 is cooperatively transported by the mobile crane device 10A, the equipment cost per transport weight can be reduced as compared with the cooperative transport using a conventional manipulator or the like. Therefore, it is advantageous for transporting heavy objects.

Further, when the operation is performed by giving the operation command to the destination to the reader 11, the follower 12 estimates the operation of the reader 11 from the change of the position of the transport object 1, the wire 6 or these predetermined parts, Since each target position is determined and operated, it is not necessary to give an operation command to a plurality of mobile crane apparatuses , and communication between the leader 11 and the follower 12 and between the followers 12 is not necessary.
For this reason, it is only necessary to change the operation command of the reader 11 when changing the destination as compared with the case where the operation command (target trajectory) is given to all the mobile crane devices, and the control of the follower 12 is changed. There is an advantage that it is unnecessary. Further, even when the mobile crane apparatus 10A serving as the reader 11 is operated by a human operation (operation or remote control), cooperative transport is possible.

Further, since the follower 12 operates so as to hold the relative position between the leader 11 and the follower 12 at the relative position between the leader 11 and the follower 12 in the initial state, each mobile crane apparatus 10A is transported during transport of the moving object. The transport object 1 can be reliably transported to the destination without colliding close to the object 1 or falling apart due to the weight of the transport object 1 due to the distance between the mobile crane devices being too far.

  As described above, since the error due to the shake of the transport object 1 is corrected at the position detected based on the image captured by the imaging device 8, the operation (position, orientation) of the reader 11 can be accurately estimated. For this reason, each follower 12 can stably convey the conveyed object 1 while keeping the relative position to the reader 11 constant.

In addition, although said embodiment demonstrated the case where the number of the followers 12 was one, this invention is not limited to this, Of course, it is applicable also when the number of the followers 12 is two or more. That is, in the above embodiment, the algorithm (Equation 1 to Equation 9) for estimating the operation of the reader 11 when there is one follower 12 has been described. However, the above-described book can be obtained even when there are two or more followers 12. An algorithm can be constructed based on the technical idea of the invention.
In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.

It is a schematic diagram of the cooperative conveyance apparatus concerning embodiment of this invention. It is a figure explaining a change of a marker position when a reader operates. It is a figure which shows the structure of the image processing part of a follower. It is operation | movement explanatory drawing of a follower when a leader turns right. It is a figure which shows the simulation result at the time of drive | working, turning right around the track | orbit of a leader. It is a figure which shows the simulation result at the time of drive | working, turning left on the track | orbit of a leader.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conveyance object 3 Moving trolley 4 Crane 5 Support | pillar 6 Wire 8 Imaging device 9 Beam 10 Cooperative conveyance device 11 Reader 12 Follower 13 Marker 15 Frame 20 Processing part 21 Position detection part 22 Error correction part 23 Operation estimation part 24 Operation control part

Claims (6)

Using a plurality of mobile crane devices that are configured to be movable and capable of suspending transported objects, and transporting the transported objects to the destination while co-suspending the transported objects with wires by the plurality of mobile crane devices ,
One of the plurality of mobile crane devices is a leader to which an operation command to the destination is given, and the other remaining mobile crane devices are followers that move while estimating the position and orientation of the reader, And an imaging device that images at least one of the wires of the crane in a state where the transported object is suspended in the follower,
An operation command to the destination is given to the reader, and the position of the transport object, the wire, or these predetermined parts in the follower coordinate system is detected from the image of the imaging device, and the detected position and the change in the position are detected. Based on the estimated position and orientation of the reader based on the estimated position and orientation of the reader, so that the relative position of the reader and the follower is held at the relative position of the reader and the follower in an initial state, Controlling the follower, a cooperative transport method characterized by the above. The imaging device is coordinated conveyance method according to claim 1, at least one of the wire of the crane in a state of suspended transport object and conveying the object imaged from above, characterized in that. The shake of the transport object due to the operation of the mobile crane device is estimated from the follower speed, and the error due to the shake of the transport object is corrected for the detected position based on the estimated value. The cooperative transport method according to claim 1 or 2 . Consists of a plurality of mobile crane devices that are configured to be movable with cranes capable of suspending transported objects, and transport the transported objects to the destination while co-suspending them with wires by the plurality of mobile crane devices. A coordinated transport device,
One of the plurality of mobile crane devices is a leader to which an operation command to a destination is given, and the other mobile crane devices are followers that move while estimating the position and orientation of the leader. Yes,
The follower
An imaging device for imaging at least one of the wires of the transported object and conveying the state of hanging objects crane,
Conveying the object from the image of the imaging device in the coordinate system of the follower, and the wire or the position detection unit for detecting the position of a given site,
An operation estimation unit that estimates the position and orientation of the reader based on the detected position and a change in the position ;
An operation control unit that controls the follower based on the estimated position and orientation of the reader so that the relative position of the reader and the follower is held at the relative position of the reader and the follower in an initial state. ,
A cooperative transport device characterized by that. The cooperative imaging apparatus according to claim 4 , wherein the imaging apparatus images at least one of the conveyance object and the wire of the crane in a state where the conveyance object is suspended from above . The follower estimates an error of the transported object due to the operation of the mobile crane device from a speed of the follower, and corrects an error due to the shake of the transported object at the detected position based on the estimated value. The cooperative transport apparatus according to claim 4 , further comprising:

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