JP2014039978A - Gripping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gripping device which can easily grasp whether or not a gripping object is normally gripped by a gripping part while suppressing complication of a configuration of the gripping device itself.SOLUTION: A gripping device 10 includes a multi-optical axis sensor 30 which detects the passage of a gripping part 12 and a gripping object H gripped by the gripping part 12 in a movement path from a gripping position to a transfer start position of the gripping part 12. A control part 20 estimates a gripping state of the gripping object H during transfer of the gripping object H from position information of the gripping part 12 and detection information of the multi-optical axis sensor 30 based on the control part 20.

Description

  The present invention relates to a gripping device that grips and transports a gripping object.

  In a so-called pick-and-place gripping device that picks up the gripping object from the storage position and transports it to the transport position, when the gripping part grips the gripping target object at the storage position, the gripping part is temporarily moved to the transport start position. After that, the object to be grasped is transported by moving to a target transport position. At this time, if the gripping object is gripped in an abnormally tilted state, such as when the gripping state is not normal, an obstacle located nearby when transporting the gripping object from the transport start position to the target transport position There is a possibility that the object to be gripped may be damaged by hitting an object or the gripping device itself may be damaged.

  Therefore, for example, Patent Document 1 discloses an article detection sensor that is provided with an article detection sensor for determining whether or not a grasped object is normally grasped. The gripping device of Patent Document 1 includes chuck claws that can be freely opened and closed at both ends of the apparatus main body, and sensors that detect the presence or absence of one end of a workpiece that is a gripping object are attached in the vicinity of one of the chuck claws. The sensor is a transmissive optical detector and has a function of detecting whether or not a workpiece exists on the optical axis. Then, after gripping the workpiece with the pair of chuck claws, the presence or absence of the workpiece is detected by a sensor, and when there is no workpiece, the signal is output to determine the mischuck state. This prevents the workpiece from being conveyed while being gripped in an abnormally inclined state with respect to the chuck pawl.

JP-A-5-32390

  However, in the gripping device of Patent Document 1, since the sensor is attached to the main body of the device, that is, the gripping portion, the sensor itself moves with the gripping operation of the workpiece by the chuck claws. Since a plurality of wires are connected to the sensor, it is necessary to devise the wiring so that the wires of the sensor are not entangled by the movement of the gripping portion, and the configuration of the gripping device itself is complicated. There's a problem.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to normally hold the object to be gripped by the gripping portion while suppressing the configuration of the gripping device itself from becoming complicated. It is an object of the present invention to provide a gripping device that can easily grasp whether or not it is present.

  In order to achieve the above object, the invention described in claim 1 has a gripping part for gripping a gripping object, and moves the gripping part from a gripping position for gripping the gripping object to a conveyance start position. And a gripping device that transports the gripping object by moving from the transport start position to the transport position, the position estimation means for estimating the position of the gripper, and the transport from the gripping position of the gripper. In the movement path to the start position, the grip unit, a light-shielding detection unit that detects passage of the gripping object gripped by the grip unit, position information of the grip unit based on the position estimation unit, and the light shielding The gist of the present invention is to include gripping state estimation means for estimating a gripping state of the gripping object by the gripping part when the gripping object is transported from detection information of a mold detection means.

  According to this invention, without attaching a sensor as in the prior art to the gripping part side, the position information of the gripping part based on the position estimation unit and the detection information of the light-shielding type detection unit can be used to convey the gripping object. The grip state of the grip target by the grip portion can be estimated by the grip state estimation means. Therefore, compared to the case where the wiring of the sensor needs to be devised as in the prior art, the gripping device can be controlled normally by the gripping portion while suppressing the complication of the configuration of the gripping device itself. It is possible to easily grasp whether or not it is gripped.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the light shielding detection means has at least two optical axes intersecting each other.
According to the present invention, the gripping unit and the gripping object are moved from the gripping position to the transport start position when compared with the case where at least two optical axes do not intersect and extend in parallel with each other. In addition, the optical axis is easily blocked by the gripping object. As a result, it is possible to easily detect the passage of the grip portion and the grip target.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the object to be grasped has a long shape, and the light-shielding detection means includes a plurality of light beams having a plurality of optical axes extending in parallel. When the gripping target object gripped by the gripping part passes through the optical axis, the longitudinal direction of the gripping target object extends along a direction intersecting with the direction in which the optical axis extends. Further, the present invention further includes a posture control means for controlling the posture of the grip portion.

  According to this invention, when the gripping object gripped by the gripping part passes through the optical axis, the gripping target is compared with the case where the longitudinal direction of the gripping target extends along the direction in which the optical axis extends. It is possible to increase the number of optical axes that are blocked by the object, and to further easily detect the passage of the grasped object.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the gripping state estimation is performed in the middle of moving the gripping object from the gripping position to the transport start position. The gist is that when the gripping state is estimated to be not normal by the means, the gripping object conveyance operation is stopped and the gripping object is gripped again by the gripping unit.

  According to this invention, while the gripping object is moved from the gripping position to the transport start position, the gripping object is transported even though it is estimated that the gripping state estimated by the gripping state estimation unit is not normal. Compared with the case where the operation is continued and the gripping object is moved to the transport start position, the transporting operation of the gripping object can be performed efficiently.

  According to the present invention, it is possible to easily grasp whether or not the grasped object is normally grasped by the grasping portion while suppressing the complication of the structure of the grasping device itself.

(A) is the schematic of the holding | grip apparatus in embodiment, (b) is a block diagram which shows the electrical structure of a holding | grip apparatus. The table | surface which shows the holding state of the holding target estimated from the position of a holding part and the detection information of a multi-optical axis sensor. The schematic diagram of the grasping device in another embodiment.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1A, the apparatus main body 11 of the gripping apparatus 10 is connected to a gripping part 12 that grips a long gripping object H housed in a box H1 and the gripping part 12. Arm portion 13. The arm portion 13 is provided with a plurality of motors 14 that can adjust the angle of the arm portion 13. The angle of the arm portion 13 is adjusted by driving each motor 14, and the position of the grip portion 12 can be adjusted by adjusting the angle of the arm portion 13.

  Specifically, by adjusting the angle of the arm portion 13 by driving each motor 14, the grip portion 12 is inserted into the box H1 and positioned at a grip position where the grip object H is gripped in the box H1. Thus, the position of the grip portion 12 can be adjusted. Further, by adjusting the angle of the arm portion 13 by driving each motor 14, the grip portion 12 is moved from the grip position to the transport start position set above the box H1, and the grip portion 12 is moved to the transport start position. The position of the grip portion 12 can be adjusted so as to be positioned. Further, by adjusting the angle of the arm portion 13 by driving each motor 14, the grip portion 12 is moved from the transport start position to the target transport position, and the grip portion 12 is positioned at the transport position. The position of the part 12 can be adjusted. In this way, the gripping object H accommodated in the box H1 is gripped by the gripping part 12 and can be transported to the transport position.

  The gripping device 10 includes a multi-optical axis as a light-shielding detection unit that detects the gripping unit 12 and the passage of the gripping target object H gripped by the gripping unit 12 in the movement path from the gripping position to the transport start position in the gripping unit 12. A sensor 30 is provided. The multi-optical axis sensor 30 includes a light projecting unit 31 and a light receiving unit 32, and the light projecting unit 31 and the light receiving unit 32 are arranged to face each other above the box H1, and the pair of support columns 33 are arranged. And is supported by a part of the gripping device 10. The light projecting unit 31 has a plurality of light projecting elements 31a arranged on a straight line, and the light receiving unit 32 has a plurality of light receiving elements 32a arranged on a straight line. A plurality of optical axes emitted from the light projecting elements 31a extend in parallel, and can be received by the light receiving elements 32a arranged to face each other. The multi-optical axis sensor 30 is separate from the apparatus main body 11.

  As shown in FIG. 1B, each motor 14 is connected to a control unit 20 provided in the apparatus main body 11. Then, each motor 14 is driven and controlled according to a command from the control unit 20, and the driving of the arm unit 13 is controlled. Each motor 14 is provided with a rotation angle detector 14 a that detects the rotation angle of each motor 14. Each rotation angle detection unit 14 a is connected to the control unit 20. And while the rotation angle detection information detected by each rotation angle detection part 14a is sent to the control part 20, the control part 20 is based on the rotation angle detection information sent from each rotation angle detection part 14a. Twelve positions can be estimated. Therefore, in this embodiment, the control unit 20 functions as a position estimation unit that estimates the position of the grip unit 12. A light receiving unit 32 is connected to the control unit 20, and a signal from the light receiving unit 32, that is, detection information of the multi-optical axis sensor 30 is sent to the control unit 20.

Next, the operation of this embodiment will be described.
FIG. 2 is a list showing the gripping state of the gripping target object H estimated from the position of the gripping unit 12 estimated by the control unit 20 and the detection information of the multi-optical axis sensor 30. Note that the position of the grip portion 12 is always estimated by the control unit 20 based on the rotation angle detection information sent from each rotation angle detection unit 14a.

  As shown in FIG. 2, when the grip portion 12 is inserted into the box H1 and positioned at the grip position where the grip target H is gripped in the box H1, the optical axis emitted from the light projecting portion 31 is It is blocked by the device body 11. Even when the grip portion 12 moves from the grip position to the height of the optical axis position where the multi-optical axis sensor 30 is provided, the optical axis emitted from the light projecting portion 31 is blocked by the grip portion 12.

  Subsequently, when the gripper 12 passes the optical axis position and the optical axis emitted from the light projecting unit 31 is blocked by the gripping target H, the controller 20 causes the gripper 12 based on the controller 20 to be blocked. The gripping state that the gripping object H is gripped by the gripping unit 12 is estimated from the position information of the sensor and the detection information of the multi-optical axis sensor 30. Therefore, the control unit 20 functions as a gripping state estimation unit that estimates the gripping state of the gripping target H by the gripping unit 12 when the gripping target H is transported.

  In addition, as shown to Fig.1 (a), when the holding object H hold | gripped by the holding part 12 passes an optical axis, the longitudinal direction of the holding object H is a direction orthogonal to the direction where an optical axis is extended. The posture of the grip portion 12 is controlled so as to extend along the line. Specifically, the attitude of the gripping unit 12 is controlled by controlling the driving of each motor 14 according to a command from the control unit 20. Therefore, the control unit 20 also functions as a posture control unit that controls the posture of the grip unit 12.

  On the other hand, as shown in FIG. 2, when the gripper 12 passes through the optical axis position, when the optical axis emitted from the light projecting unit 31 is not blocked by the gripping target H, the control unit 20 An abnormal gripping state in which the gripping object H is not gripped by the gripper 12 is estimated from the position information of the gripper 12 based on the control unit 20 and the detection information of the multi-optical axis sensor 30.

  Further, when the gripper 12 reaches the optical axis passage position, the light axis emitted from the light projector 31 is blocked by the gripping object H gripped by the gripper 12, and then from the light projector 31. It is assumed that a signal indicating that all the emitted optical axes are received by the light receiving unit 32 is sent from the light receiving unit 32 to the control unit 20. Then, the control unit 20 has grasped the object H to be grasped by the grasping unit 12 from the position information of the grasping unit 12 based on the control unit 20 and the detection information of the multi-optical axis sensor 30. An abnormal gripping state in which the gripping object H has dropped after reaching the optical axis passing position is estimated.

  Subsequently, when the gripper 12 reaches the transport start position and the optical axis emitted from the light projecting unit 31 is blocked by the gripping target H, the controller 20 causes the gripper 12 based on the controller 20 to be blocked. Based on the position information and the detection information of the multi-optical axis sensor 30, an abnormal gripping state in which the gripping object H gripped by the gripping part 12 is gripped in an abnormally tilted state with respect to the gripping part 12 is obtained. presume.

  Then, when the control unit 20 estimates an abnormal gripping state in which the gripping object H gripped by the gripping unit 12 is gripped in an abnormally tilted state with respect to the gripping unit 12, the control unit 20 drives each motor 14. To stop. This prevents the gripping target H from being transported toward the transport position while being gripped in an abnormally inclined state with respect to the gripping portion 12. As a result, when the gripping target H is transported from the transport start position to the transporting position, the gripping target H is prevented from being caught by an obstacle located near the box H1 or the gripping target H. ing.

  On the other hand, if the optical axis emitted from the light projecting unit 31 is not blocked by the gripping object H when the gripping unit 12 reaches the transport start position, the control unit 20 grips based on the control unit 20. From the position information of the part 12 and the detection information of the multi-optical axis sensor 30, the gripping object H gripped by the gripping part 12 is normally not gripped with respect to the gripping part 12 and is normally gripped. Correct gripping state is estimated.

  Then, when the control unit 20 estimates a normal gripping state in which the gripping object H gripped by the gripping unit 12 is normally not gripped with respect to the gripping unit 12 and is normally gripped, each motor 14 To control the drive of the arm portion 13 and move the grip portion 12 to the transport position. As a result, when the gripping object H is transported from the transport start position to the transport position, the gripping object H is transported to the transport position without being caught by an obstacle or the like located in the vicinity of the box H1 or the gripping object H. Is done.

In the above embodiment, the following effects can be obtained.
(1) The gripping device 10 includes a multi-optical axis sensor 30 that detects the passage of the gripping unit 12 and the gripping target object H gripped by the gripping unit 12 in the movement path from the gripping position of the gripping unit 12 to the conveyance start position. I have. Further, the control unit 20 determines the gripping state of the gripping target H by the gripping unit 12 during the transport of the gripping target H from the position information of the gripping unit 12 based on the control unit 20 and the detection information of the multi-optical axis sensor 30. Is estimated. According to this, since it is not necessary to attach a sensor as in the prior art to the gripping portion 12 side, the gripping device 10 itself is compared with the case where the wiring of the sensor needs to be devised as in the prior art. It is possible to easily grasp whether or not the grasped object H is normally grasped by the grasping portion 12 while suppressing the complication of the configuration.

  (2) When the gripping target object H gripped by the gripping part 12 passes through the optical axis, the control unit 20 extends along the direction in which the longitudinal direction of the gripping target object H is orthogonal to the direction in which the optical axis extends. Thus, the posture of the grip portion 12 is controlled. According to this, when the gripping target H gripped by the gripping part 12 passes through the optical axis, the longitudinal direction of the gripping target H is longer than the case where the optical axis extends along the direction in which the optical axis extends. It is possible to increase the number of optical axes that are blocked by the gripping target H, and to further easily detect the passage of the gripping target H.

  (3) According to the present embodiment, since there is no need to attach a sensor as in the prior art to the gripping part 12 side, when the gripping part 12 tries to grip the gripping target object H, the sensor is It is possible to avoid a problem that the sensor itself hits an obstacle such as the box H1 or the like and causes a defect in the sensor itself.

In addition, you may change the said embodiment as follows.
As shown in FIG. 3, a light-shielding detection unit that emits an optical axis so that the optical axis extends in a direction orthogonal to the direction in which the optical axis emitted from the light projecting unit 31 of the multi-optical axis sensor 30 extends. A multi-optical axis sensor 40 may be further provided. The multi-optical axis sensor 40 includes a light projecting unit 41 and a light receiving unit 42, and the light projecting unit 41 and the light receiving unit 42 are arranged so as to face each other above the box H1. And is supported by a part of the gripping device 10. The light projecting unit 41 has a plurality of light projecting elements 41a arranged on a straight line, and the light receiving unit 42 has a plurality of light receiving elements 42a arranged on a straight line. A plurality of optical axes emitted from the light projecting elements 41a extend in parallel, and can be received by the light receiving elements 42a arranged to face each other. The multi-optical axis sensor 40 is separate from the apparatus main body 11. According to this, when the grip part 12 and the grip target H are moving from the grip position to the transport start position, the optical axis is easily blocked by the grip part 12 and the grip target H. As a result, it is possible to easily detect the passage of the grip portion 12 and the gripping object H. In short, the multi-optical axis sensor 40 may be provided to have at least two optical axes that intersect each other.

  ○ In the embodiment, when it is estimated that the gripping state estimated by the control unit 20 is not normal while moving the gripping object H from the gripping position to the transport start position, the transport operation of the gripping target H is stopped. And you may make it hold | grip the holding object H by the holding part 12 again. According to this, in the middle of moving the gripping object H from the gripping position to the transport start position, the gripping object H is transported even though it is estimated that the gripping state estimated by the control unit 20 is not normal. Compared to the case where the operation is continued and the gripping target H is moved to the transport start position, the transporting operation of the gripping target H can be performed efficiently.

In the embodiment, when the grasped object H grasped by the grasping unit 12 passes through the optical axis, the longitudinal direction of the grasped object H may extend along the direction in which the optical axis extends.
In the embodiment, the shape of the gripping target H is not particularly limited.

  In the embodiment, the optical axis emitted from the light projecting unit is reflected by a reflecting plate (mirror), and the optical axis reflected by the reflecting plate is received by the light receiving unit. Also good.

  In the embodiment, as the light shielding type detection means, for example, the light axis emitted from the light projecting unit is blocked by the gripping unit 12 or the gripping target H, so that the light projecting unit and the gripping unit 12 or the gripping target H Alternatively, an optical distance measuring sensor capable of measuring the distance may be used.

  In the embodiment, the multi-optical axis sensors 30 and 40 may be configured such that the installation position can be freely changed according to the box H1 or the grasped object H.

  DESCRIPTION OF SYMBOLS 10 ... Gripping device, 12 ... Gripping part, 20 ... Control part functioning as position estimation means, grasping state estimation means, and posture control means, 30, 40 ... Multi-optical axis sensor as light shielding type detection means, H ... Grasping object object.

Claims (4)

It has a gripping part that grips the gripping object,
A gripping device that moves the gripping object from a gripping position for gripping the gripping object to a transport start position and moves the gripping object from the transport start position to a transport position;
Position estimating means for estimating the position of the gripping part;
A light-shielding type detecting means for detecting passage of the gripping part and the gripping object gripped by the gripping part in a movement path from the gripping position of the gripping part to the transport start position;
Gripping state estimation for estimating the gripping state of the gripping object by the gripping unit during transport of the gripping object from the position information of the gripping part based on the position estimation unit and the detection information of the light shielding type detection unit And a gripping device.   The gripping device according to claim 1, wherein the light-shielding detection unit has at least two optical axes that intersect each other. The gripping object is elongated, and
The light shielding type detection means is a multi-optical axis sensor in which a plurality of optical axes extend in parallel,
When the gripping target object gripped by the gripping part passes through the optical axis, the longitudinal direction of the gripping target object extends along a direction intersecting the direction in which the optical axis extends. The gripping device according to claim 1 or 2, further comprising posture control means for controlling the posture.   In the middle of moving the gripping object from the gripping position to the transport start position, when the gripping state estimation means estimates that the gripping state is not normal, the transporting operation of the gripping object is stopped, The gripping apparatus according to any one of claims 1 to 3, wherein the gripping object is gripped again by the gripping unit.