JP2010240838A - Position management method for moving object, and robot controller applying the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position management method for a moving object preventing double registration of the moving object without complicating a device, and a robot controller applying the method. <P>SOLUTION: The method is provided for detecting the position of a workpiece conveyed by a conveyor 1, by a camera 2 and an image processor, and managing the detected position data of the workpiece. A queue for managing the position data is provided, and the position data is registered in the queue to carry out sequential updating based on the operation amount of the conveyor 1. When the position data is registered in the queue, the position data to be registered is compared with position data already registered in the queue, and when the position data indicating the same workpiece is already registered in the queue, the position data is not registered. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for managing the position of a moving object conveyed by a transport device such as a conveyor, and a robot controller to which the method is applied.

  Conventionally, there is a robot system that tracks a moving object (hereinafter referred to as a workpiece) conveyed by a conveyor and performs a robot operation on the workpiece. When this type of system targets multiple workpieces, In many cases, a camera and an image processing device are used for detecting the position of a workpiece so that the workpieces can be dealt with even when they are discretely arranged on a conveyor.

  By the way, when robot work is performed on a workpiece that flows at a low speed as in a conventional automobile welding line, information on the detected workpiece, such as the type of workpiece and the position of the workpiece, is immediately transmitted to the processing device. If there are multiple workpieces as described above, or if there is variation in the interval at which the workpieces reach the movable range of the robot, the next workpiece is If the information of the detected workpiece is immediately transmitted to the processing device, a problem occurs. For this reason, it is necessary to store information by some method until the end of the current operation, and there is a queue (FIFO) structure as a general data storage method in such a case. This queue has a structure that allows three operations of registration, reference, and deletion of data, and can store a plurality of pieces of information at the same time, and the data is referred to in the order of registration. Even in a system that performs position detection using an apparatus, position management using this queue is performed.

Here, the position detection using the camera and the image processing apparatus will be briefly described.
FIG. 10 illustrates the camera field of view at each shooting timing with the camera. A1 to A3 in the figure show the respective camera fields (A3: current camera field, A2: previous camera field, A1: previous camera field). The moving direction of the conveyor 102 is the right direction in the figure. As described above, in the position detection using the camera 101 and the image processing apparatus as described above, shooting is performed with shooting timings such that the camera fields of view at each shooting timing do not overlap each other. . This is a configuration for eliminating double registration of the position data of the same work in the queue due to the image of one work being taken twice.

  As described above, the position data of each workpiece detected from each captured image captured without overlapping the camera field of view is sequentially registered in the queue as described above, and given to the processing unit as appropriate, and the robot operation is performed. It has come to be. FIG. 12A, which will be described later, shows a queue in which all the works W1 to W6 shown in FIG. 10 are registered.

Hereinafter, the robot operation related to the use of the position data registered in the queue in this way will be described.
FIG. 11 is a diagram showing an example of a user program describing the robot operation, which describes the robot operation for sequentially handling the workpieces W1 to W6 flowing on the conveyor 102. FIG. FIG. 12 is a diagram showing how the queue changes when the user program of FIG. 11 is executed. Note that each storage location of the queue illustrated in FIG. 12 corresponds to QUEUE (1) to QUEUE (6) of the user program in order from the bottom.

  When the user program shown in FIG. 11 is executed, first, the robot moves to the position indicated by the head data of the queue by the execution of the first line, and the work W1 at the position is handled. The head data of the queue (that is, the position data of the work W1) is deleted. As a result, the queue has a configuration in which the position data of the workpieces W2 to W6 are shifted in the head direction as shown in FIG. Subsequently, the work W2 is handled in the same manner in the third line, and the position data of the work W2 is deleted in the fourth line. As a result, the queue has a configuration in which the position data of the workpieces W3 to W6 are shifted in the head direction as shown in FIG. Next, the workpiece W3 is handled in the fifth line, and the position data of the workpiece W3 is deleted. As a result, the queue is as shown in FIG. Similarly, handling of W4 to W6 and deletion of queue data are repeated.

  As described above, in the conventional method, images are taken so that the camera fields of view do not overlap each other so that one work is not registered twice in the queue, and it is difficult to match the timings. there were. In addition, since a configuration for matching the timing is required, the apparatus becomes complicated. Further, even if such a configuration is adopted, if there is unevenness in the conveyor speed, it is difficult to compensate. .

  In addition, since the queue is a data structure that is read (referred to data) in the order of registration, it can only deal with applications that handle in the order of workpiece transfer as described above, and it is difficult to deal with various recent applications. Lacked flexibility. Specifically, for example, when the body part of an elongated part flowing on a conveyor is gripped by a robot hand having a bifurcated tip, three elongated parts are on the conveyor, and the first and third parts are in the same direction. If the second part is transported at an angle of 90 degrees with respect to the first and third parts, the conventional method requires gripping in the order of flow. After gripping the part, it is necessary to rotate the wrist 90 degrees to grip the second part and then rotate it 90 degrees again to grip the third part. However, instead of handling in the order of conveyance in this way, if the first part is gripped and then the third part is taken and then the second part is taken, the wrist rotates. The operation may be performed once and a high-speed operation can be obtained. Nevertheless, the conventional location management method cannot perform such an operation, which hinders application development. Similarly, if two types of workpieces A and B flow on the conveyor using a bifurcated robot hand, the workpieces that have flowed in the order of A, B, and A will be handled continuously by A. However, it was impossible in the past.

  The present invention has been made in view of the above points, and provides a moving object position management method capable of preventing double registration of a moving object without complicating the apparatus, and a robot controller to which the method is applied. The first purpose is to provide.

  In addition to the first object described above, the second object of the present invention is to provide a moving object position management method capable of flexibly supporting various applications and a robot controller to which the method is applied. It is a thing.

  (1) A moving object position management method according to one aspect of the present invention is a method of detecting the position of a moving object conveyed by a transporting device using an imaging unit and managing the detected position data of the moving object. In addition, a queue for managing the position data is provided, and the position data is registered in the queue and updated sequentially based on the operation amount of the transport device. When the position data is registered in the queue, the position data to be registered is registered. Is compared with the position data already registered in the queue, and is not registered when the position data indicating the same moving object is already registered in the queue.

  According to the present invention, when registering position data in a queue, the position data to be registered is compared with position data already registered in the queue, and position data indicating the same moving object is already stored in the queue. Since it is not registered if registered, if there is an area where the imaging area by the imaging means overlaps in the previous and current imaging timing, even if there is a moving object in the overlapping area, the movement It is possible to prevent object position data from being registered twice in the queue.

  (2) In the moving object position management method according to another aspect of the present invention, in the above (1), the cue is not limited to the head data, but the position data at an arbitrary position is referred to.

  According to the present invention, it is possible to refer to position data at an arbitrary position in the queue, so it is possible to refer to position data that is not limited to the registration order in the queue, and it is excellent in flexibility when developing an application that uses position data. A moving object position management method can be obtained.

  (3) In the moving object position management method according to another aspect of the present invention, in the above (1) or (2), the position data registered in the queue is used for a robot that performs a predetermined operation on the moving object. This is referred to as the operation position.

  According to the present invention, position data registered in a queue can be referred to as an operation position for a robot that performs a predetermined operation on a moving object.

  (4) A moving object position management method according to another aspect of the present invention is such that, in the above (3), the cue is shared by a plurality of robots.

  According to the present invention, since the cue is shared by a plurality of robots, it is possible to easily construct a robot system in which a plurality of robots track a moving object on a transport device and operate on the moving object. Position management method can be obtained.

  (5) A robot controller according to one aspect of the present invention is a robot controller that detects a position of a moving object conveyed by a transport device by an imaging unit and manages the detected position data of the moving object by a queue. A queue storage unit for storing the position data of the moving object, a queue operation unit for sequentially registering the position data of the moving object detected by the imaging means in the queue storage unit, and the position data of the moving object registered in the queue storage unit. A queue updating unit that sequentially updates based on the operation amount of the transport device, and when the queue operation unit registers the position data in the queue storage unit, the position data to be registered and the queue storage unit are already registered in the queue storage unit. The position data indicating the same moving object is not registered if it is already registered in the queue storage unit. Those were.

  According to the present invention, when registering position data in a queue, the position data to be registered is compared with position data already registered in the queue, and position data indicating the same moving object is already stored in the queue. Since it is not registered if registered, if there is an area where the imaging area by the imaging means overlaps in the previous and current imaging timing, even if there is a moving object in the overlapping area, the movement It is possible to prevent object position data from being registered twice in the queue.

  (6) In the robot controller according to another aspect of the present invention, in the above (5), the cue operation unit is configured to be able to refer to position data registered at an arbitrary position, not limited to the head data of the cue storage unit. Is.

  According to the present invention, since position data at an arbitrary position in the queue storage unit can be referred from the queue operation unit, it is possible to refer to position data that is not limited to the order of registration in the queue, and in developing an application using the position data. Thus, a robot controller that provides a flexible position management method can be obtained.

  (7) In the robot controller according to another aspect of the present invention, in the above (5) or (6), the cue operating unit refers to the position data registered in the cue storage unit, and performs predetermined processing on the moving object. This is output as position data for operating the robot that performs the operation.

  According to the present invention, the position data in the cue storage unit can be referred to as the operation position for the robot that performs a predetermined operation on the moving object.

  (8) A robot controller according to another aspect of the present invention is the robot controller according to (7), wherein the queue storage unit is shared by a plurality of robots.

  According to the present invention, since the cue is shared by a plurality of robots, a robot controller that can easily construct a robot system that tracks a moving object on a transport device by a plurality of robots and operates the moving object. Can be obtained.

It is a functional block diagram of the robot controller according to the first embodiment of the present invention. It is a figure which shows the software structure of Embodiment 1 of this invention. It is a schematic block diagram of the system to which the position management method of the moving object of Embodiment 1 of this invention is applied. It is a figure which shows the camera visual field for every imaging | photography timing. It is a figure which shows an example of a user program. It is a figure which shows the mode of a change of the queue of a queue memory | storage part when the user program of FIG. 5 is executed. It is a schematic block diagram of the system to which the position management method of the moving object of Embodiment 2 of this invention is applied. It is a figure which shows an example of the user program in the case of using a some robot. It is a figure which shows the mode of the change of the queue of a queue memory | storage part at the time of executing the user program of FIG. It is explanatory drawing of the conventional imaging | photography timing. It is a figure which shows an example of the conventional user program. It is a figure which shows the mode of a change of a queue when the user program of FIG. 10 is executed.

Embodiment 1 FIG.
1 is a functional block diagram of the robot controller according to the first embodiment of the present invention, FIG. 2 is a diagram showing a software configuration of the first embodiment of the present invention, and FIG. 3 is a position of a moving object according to the first embodiment of the present invention. It is a schematic block diagram of the system to which the management method is applied.
In the figure, 1 is a conveyor as a conveying device, 2 is a camera as imaging means for detecting the position of a workpiece together with an image processing device (not shown) that images the conveyor 1 and processes the captured image, and 3 is a conveyor. 1 is an encoder for detecting the amount of movement of the conveyor 1, 4 is a robot, and the conveyor 1, the camera 2, the encoder 3 and the robot 4 are connected to a robot controller 5 to constitute a system.

  The robot controller 5 includes a user program storage unit 11 that stores a user program, a user program execution unit 12 that executes a user program stored in the user program storage unit 11, a current workpiece detected by the camera 2 and the image processing apparatus. A queue storage unit 13 for storing a position data queue indicating a position (hereinafter simply referred to as position data), a queue operation unit 14 for performing operations for registration, reference, and deletion of position data in the queue storage unit 13, the queue storage The queue update unit 15 that sequentially updates the position data of the unit 13 based on the operation amount of the conveyor 1, generates a trajectory (angle of each joint) of a work point (robot hand), converts this into a motor command value, and will be described later According to the motor command value from the trajectory generator 16 and the trajectory generator 16 to be output to the motor controller 18. It has a configuration which includes a motor controller 17 which controls the over motor 4a. The trajectory generation unit 16 is activated at predetermined sampling times by hardware such as an external timer or an operating system (OS) described later.

  As shown in FIG. 2, the software configuration of the robot controller 5 includes a user program, an operating system (OS) that controls the robot controller 5, has an event function, a multitask function, and the like, and positions of the robot 4 and the conveyor 1. And a control program for performing detection and the like.

  The queue storage unit 13 has a data structure capable of referring to an element at an arbitrary position (here, position data), and is strictly different from a general FIFO (First In First Out) type queue. However, there is no change in the structure in which each element registered after the deleted element is shifted toward the head of the queue after the reference and deletion of the element in the queue storage unit 13 is performed.

  When registering position data in the queue storage unit 13, the queue operation unit 14 compares the position data with the position data already registered in the queue storage unit 13, and the same position data is already stored in the queue storage unit 13. If it is registered, the position data is not registered because it is determined that the same workpiece has already been registered. As described above, when registering the position data, the position data is compared with the position data in the queue storage unit 13 and the registration to the queue is restricted according to the comparison result, thereby providing the following advantages.

FIG. 4 is a diagram for explaining the advantages, and particularly shows the camera field of view at each photographing timing by the camera 2. A1 to A4 in the figure indicate the respective camera fields (A4: current camera field of view, A3: previous camera field of view, A2: previous camera field of view, A1: previous camera field of view), and W1 to W6 indicates a workpiece.
Conventionally, as described above, the double registration of workpieces is prevented with a configuration in which the camera fields of view do not overlap each other. However, even if the camera fields of view overlap, there is no problem here. That is, for example, the workpiece W2 in the area where the camera fields of view A1 to A4 overlap each other (hatched area in the figure) is subjected to position detection in each of the areas of the camera fields of view A1 and A2, but the position data is the camera field of view A1 Is registered in the queue storage unit 13, but registration is not performed in the next camera field of view A2 because it has already been registered in the previous camera field of view A1. Thus, by performing a check at the time of registration in the queue storage unit 13, it is possible to easily prevent double registration of a workpiece. Similarly, double registration is also prevented for the workpiece W5.

  Further, the queue operation unit 14 refers to the position data in the queue storage unit 13 and performs an operation of outputting the position data to a component that requires the position data. For example, when a command for instructing display of position data is executed by the user program execution unit 12, the position data in the queue storage unit 13 is referred to, and the position data is output to the user program execution unit 12, When an operation command such as “JUMP QUEUE (1)” is executed, an operation to output to the trajectory generation unit 16 is performed with reference to the head data of the queue.

Next, the operation of the first embodiment will be described.
When a predetermined program is executed, the camera 2 starts photographing the workpiece flowing on the conveyor 1, detects the workpiece from the photographed image, and registers its position data in the queue storage unit 13 by the cue operation unit 14. . At this time, the cue operating unit 14 compares the position data to be registered this time with the position data already registered in the cue storage unit 13, and registration of the position data indicating the same work in the cue storage unit 13 is performed. Register when not. The position data registered in the queue storage unit 13 is sequentially updated by the queue update unit 15 based on the pulse signal from the encoder 3.

  Here, for example, when the workpieces W1 to W6 are conveyed on the conveyor 1 as shown in FIG. 4, first, the position data of the workpiece W1 and the workpiece W2 included in the first camera field of view A1 of the camera 2 are queued in this order. Registered in the unit 13. Next, the workpiece W2 and the workpiece W3 are detected from the next camera field of view A2, and these position data are registered in the cue storage unit 13. However, since the position data of the workpiece W2 has already been registered, the registration is performed. Only the work W3 is registered in the queue storage unit 13 without being performed. Similarly, the workpieces W4 to W6 are also registered. As a result, the queue in the queue storage unit 13 has a configuration in which the workpieces W1 to W6 are registered in order from the top as shown in FIG.

FIG. 5 is a diagram showing an example of a user program.
Consider the case where the user program shown in FIG. 5 is executed. This user program shows a program example in the case where two types of workpieces (triangle and quadrangle) are mixed and flow on the conveyor 1 and handling is performed alternately. Here, W1, W2, and W4 are rectangular workpieces, and W3, W5, and W6 are triangular workpieces. In the figure, the text after “′” is a comment text.

  FIG. 6 is a diagram showing how the queue of the queue storage unit changes when the user program shown in FIG. 5 is executed. FIG. 6A shows a state before the user program is executed. Each storage location of the queue corresponds to QUEUE (1) to QUEUE (6) of the user program in order from the bottom.

  When this user program is executed by the user program execution unit 12, first, by executing the first line (JUMP QUEUE (1)), the queue operation unit 14 refers to the head data of the queue, and the head data, that is, the work The position data of W1 is output to the trajectory generator 16. The trajectory generation unit 16 generates a trajectory for operating the robot 4 on the workpiece W1, converts the joint angle into a motor command value, and outputs the motor command value to the motor control unit 17. The motor control unit 17 performs control so that each joint of the robot 4 is operated according to the motor command value. As a result, the robot 4 moves the robot hand to the workpiece W1 (rectangular workpiece) for handling. In the second line, the queue operation unit 14 deletes the head data of the queue (that is, the position data of the work W1). As a result, the head data in the queue that was initially in the state shown in FIG. 6A is deleted as shown in FIG. 6B, the position data of the workpieces W2 to W6 are shifted in the head direction, and the position data of the workpiece W2 Is positioned at the head of the queue.

  Subsequently, the workpiece W3 (triangular workpiece) indicated by the second position data from the head of the queue is handled in the third line, and the second data from the head of the queue, that is, the position of the work W3 is displayed in the fourth line. Data is removed from the queue. As shown in FIG. 6C, the deleted queue has a configuration in which the position data of the work W3 is deleted and the position data of the works W4 to W6 are shifted toward the head of the queue.

  Subsequently, in the fifth line, the robot operation to the position indicated by the head data of the queue (that is, the position data of the work W2) is performed, and the work W2 (rectangular work) at the position is handled. Delete location data from the queue. In the queue after the deletion, as shown in FIG. 6D, the position data of the work W2 is deleted, the position data of the works W4 to W6 are shifted toward the head of the queue, and the position data of the work W4 is placed at the head of the queue. It will be in the position. Similarly, the workpiece W5 (triangular workpiece) is handled, its position data is deleted, and the queue becomes as shown in FIG. 6E, and subsequently the workpiece W4 (rectangular workpiece) and workpiece W6 (triangular workpiece) are handled. And the corresponding position data is similarly deleted.

  According to the first embodiment, when registering position data in the queue storage unit 13, when position data indicating the same workpiece as compared with the position data already registered in the queue storage unit 13 is registered. Is not registered, so that it is possible to prevent double registration by software without taking a special hardware configuration.

  In addition, when referring to the queue in the queue storage unit 13, it is possible to refer not only to the head of the queue but also to an arbitrary position, so that it is possible to develop an application that handles workpieces in a desired order. It becomes possible to construct a system that is more versatile than the prior art, which is limited to refer to in order. Specifically, for example, as described above, when various types of workpieces are mixed and flow on the conveyor 1, it is possible to construct a system such as alternately handling workpieces.

  In addition, since the position data of the work is managed by the queue, the position management of each work when a plurality of work flows on the conveyor 1 becomes easy.

Embodiment 2. FIG.
The first embodiment shows the position management in a system in which one robot is arranged for one conveyor, but the second embodiment has one conveyor 1 as shown in FIG. On the other hand, it relates to position management in a system in which a plurality of robots 4 (here, two robots, in particular, the upstream robot is denoted by 4a and the downstream robot is denoted by 4b). When a plurality of robots 4 are installed in this way, one queue is shared by the plurality of robots 4. Here, the description will be made on the assumption that the queue is in the state shown in FIG. 9A (described later) before execution of the user program by the same photographing as in FIG.

FIG. 8 shows an example of a user program. FIG. 9 is a diagram showing how the queue of the queue storage unit changes when the user program of FIG. 8 is executed.
When this user program is executed by the user program execution unit 12, ROBOT1 (here, robot 4a) is selected by executing the first line. Then, by executing the second line, the queue operation unit 14 refers to the head data of the queue, and outputs the head data, that is, the position data of the workpiece W1 to the trajectory generation unit 16. Thereby, the workpiece W1 is handled by the robot 4a. In the third line, the queue operation unit 14 deletes the position data of the workpiece W1. As a result, the queue that was initially in the state shown in FIG. 9A is deleted as shown in FIG. 9B, and the position data of the workpieces W2 to W6 are shifted in the direction of the head of the queue. Become.

  Subsequently, ROBOT2 (in this case, the robot 4b) is selected in the fourth line, the work W2 indicated by the head data in the queue is handled by the robot 4b in the fifth line, and the position data of the work W2 is deleted in the sixth line. . As shown in FIG. 9B, the deleted queue has a configuration in which the position data of the workpiece W2 is deleted and the position data of the workpieces W3 to W6 are shifted toward the head of the queue.

  As described above, even when a plurality of robots are arranged, since the cue is shared by a plurality of robots, substantially the same operations and effects as those of the first embodiment can be obtained, and the conveyor 1 A system for handling a plurality of workpieces with a plurality of robots 4 can be easily realized.

  Conventionally, when two robots are installed on one conveyor and each robot 4 handles a workpiece, a camera is installed for each robot and a cue is provided for each robot. . In the conventional system configured in this way, for example, when an application for handling a workpiece missed by an upstream robot is handled by a downstream robot, the workpiece missed by the upstream robot is re-recognized by the downstream camera, The position data of the workpiece is deleted from the queue of the upstream robot, registered in the queue of the downstream robot, and handled by the robot on the downstream side.

  As described above, in the conventional method, since the camera is prepared for each robot, the apparatus configuration is complicated, and the re-registration of the queue is necessary, and the processing is complicated. In contrast, in the first embodiment, one camera is installed on the conveyor regardless of the number of robots installed, and workpiece position data recognized by the camera is registered in one queue, and the queue When the same application is executed, the position data of the workpiece missed by the upstream robot 4a is assigned to the downstream robot 4b without deleting it from the queue. Since it can cope (note that the position data is deleted from the queue after being assigned to the robot 4b), the system configuration is simple, and the re-registration process of the queue can be made unnecessary.

  1 conveyor, 2 cameras, 4 robots, 5 robot controllers, 13 cue storage unit, 14 cue operation unit, 15 cue update unit.

Claims (8)

A method of detecting the position of a moving object conveyed by a conveying device by an imaging means and managing position data of the detected moving object,
A queue for managing the position data is provided, the position data is registered in the queue and sequentially updated based on the operation amount of the transport device, and when the position data is registered in the queue, the position data to be registered And the position data already registered in the queue, and the position data indicating the same moving object is not registered if the position data is already registered in the queue. .   2. The moving object position management method according to claim 1, wherein the cue is not limited to the top data of the cue, and position data at an arbitrary position is referred to.   The position management method according to claim 1 or 2, wherein the position data registered in the queue is referred to as an operation position for a robot that performs a predetermined operation on the moving object.   4. The position management method for a moving object according to claim 3, wherein the cue is shared by a plurality of robots. A robot controller that detects the position of a moving object transported by a transporting device using an imaging unit, and manages position data of the detected moving object using a queue,
A queue storage unit for storing position data of a moving object;
A cue operation unit for sequentially registering the position data of the moving object detected by the imaging means in the cue storage unit;
A queue update unit that sequentially updates the position data of the moving object registered in the queue storage unit based on the operation amount of the transport device;
When registering the position data in the queue storage unit, the cue operating unit compares the position data to be registered with the position data already registered in the queue storage unit, and position data indicating the same moving object is obtained. A robot controller characterized by not registering when already registered in the queue storage unit.   6. The robot controller according to claim 5, wherein the cue operating unit is configured to be able to refer to position data registered at an arbitrary position without being limited to the head data of the cue storage unit.   The queue operation unit refers to position data registered in the queue storage unit, and outputs the position data as position data for operating a robot that performs a predetermined operation on a moving object. The robot controller according to claim 6.   The robot controller according to claim 7, wherein the queue storage unit is shared by a plurality of robots.

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