JPH0355277B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a robot hand having sensors for detecting the position of a member.

[Technical background of the invention and its problems]

When flexibility is required for product assembly, the product being assembled is transported by a conveyor or other transport device, and a robot is installed at a station along the way, and the robot sequentially assembles the required parts. is being installed. However, the robots commonly used today repeatedly move along a fixed trajectory determined in advance by teaching, etc., so they cannot grasp the required part unless it is accurately positioned. .

One method for solving this problem is to once align and transport the accumulated members, position them accurately, and then grip the members. However, this method requires not only robots and parts accumulation equipment, but also
This requires a device for aligning and conveying the members and a device for positioning them, which has the disadvantage that the entire assembly device becomes large.

Another method has been developed in which a camera is mounted on the robot, the image information obtained from the camera is processed to detect the position of the part, and the trajectory of the robot is corrected accordingly to grasp the part. There is. In this method, for example, by attaching one camera to the robot's arm, it is possible to obtain image information from the entire operating range of the robot, and from this image information, the position of the accumulated parts on the XY plane is detected. be able to. However, it is not possible to obtain component position information in the Z-axis direction perpendicular to the XY plane from the above image information, so if the component is misaligned not only in the XY-axis direction but also in the Z-axis direction, such a robot cannot grasp it. It disappears.

In order to solve this problem, the robot should be equipped with a camera that obtains image information on the XY plane and a camera that obtains image information in the Z-axis direction.
Mounting more than one camera on a robot not only complicates the processing of image information, but also reduces the weight that the robot can carry.

[Purpose of the invention]

The object of the present invention is to obtain a robot hand which has a simple structure and can detect the position of a member in three-dimensional space and accurately grasp it without limiting the payload.

[Summary of the invention]

A visual device that detects the position of the member on the XY plane is attached to the hand attached to the robot body,
A device is provided to send a signal that causes the control circuit of the robot to detect the position of the member in the Z-axis direction detected by the visual device, and the position of the member in three-dimensional space is detected by the combination of the visual device and the sensor. This allows for accurate gripping.

[Embodiments of the invention]

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

This robot hand has a mounting portion 4 having a cylindrical protrusion 2 formed on its upper end surface to be attached to an operating part of the robot such as an arm 1 of the robot, and a sliding portion 3 formed on one side surface. The slide portion 3 includes a fixed body 6 fixed to one side of the mounting portion 4 and has a U-shaped cross section and has an integral upper and lower end surface.
The slide body 7 has a key-shaped cross section and slides against the slide body 7. This slide body 7 includes a pair of guide rods 8 mounted between a pair of upper and lower end surfaces of the fixed body 6.
The guide rod 8 is inserted into the guide rod 8 between the upper end surface of the fixed body 6 and the upper end surface of the slide body 7, and is slidable in the vertical direction by the elastic pressure of a compression coil spring 9. is biased downward,
Normally, it is stopped by being pressed against a height-adjustable stopper (not shown) provided on the lower end surface of the fixed body 6. This position is the normal position of the slide body 7. The mounting part 4 is a part of this hand,
A gripping part 11 for gripping a member is fixed to the lower end of the slide body 7 and has a pair of claws 12 extending from one side of the mounting part 4 to the other side.
The pair of claws 12 are moved toward and away from each other by a claw drive mechanism housed inside a grip housing 13 attached to the lower end surface of the slide body 7, and are used to arbitrarily grip a desired member or the gripped member. can be released. However, the lever hand is attached to the visual device 1 directly or indirectly attached to the operating part of the robot.
5, and in particular, the drawing shows a camera having an optical axis in the vertical direction, adjacent to the fixing part 6 of the sliding part 3 and facing the claw 12 of the gripping part 11 on the lower end surface of the mounting part 4. The visual device 15 is shown fixed. Further, a non-contact type sensor 16 for detecting the approach of the slide body 7 is fixed to the upper end surface of the fixed body 6 of the slide portion 3.

The image information obtained from the visual device 15 is processed by a processing circuit such as a CPU, and the resulting information is sent to a control circuit of the robot and used to control the robot's operation. Further, the signal from the sensor 16 is sent to the control circuit of the robot and used to control the operation of the claws 12 of the gripping section 11.

The robot equipped with this hand operates as follows.

First, the arm 1 of the robot moves, and when the hand attached to this arm 1 comes over the assembled members,
From the image information obtained from the visual device 15, the
The position on the XY plane is detected. The robot corrects this trajectory based on the position information of the member and accurately positions the hand on the member. Subsequently, when the hand is moved forward toward the member detected by the visual device 15, the claw 12 of the grip portion 11 hits a part of the member or the XY plane that supports the member, and the slide body 7 is moved by the compression coil spring 9. Displace it in the Z-axis direction against the pressure. Thus, when the slide body 7 approaches the sensor 16, this sensor 1
Based on the signal sent from the robot 6, the robot stops the forward movement of the hand, and at the same time, the pair of claws 12
approach and grasp the member.

When the pair of claws 12 grip the member, the robot moves its hand backward. At this time, the slide body 7, which had been displaced in the direction approaching the sensor 16, returns to its normal position due to the elastic pressure of the compressed coil spring 9.

Note that the release of the gripped member can be easily inferred from the above explanation of the operation, so the explanation thereof will be omitted.

When the hand is formed as described above, the visual device 15 attached to this hand detects the position of the member on the XY plane, and the sensor 16 detects the Z-axis of the member detected by the visual device 15 from the displacement of the slide body 7. Since the position in the direction is detected, it is possible to accurately grasp a member that is misaligned three-dimensionally, and it is also possible to easily grasp various members with different heights in the Z-axis direction with the same hand. can. This hand also has one visual device in addition to the normal hand.
5, one sensor 16, and a simple slide portion 3, it can be made lightweight with no significant difference in weight from a conventional hand. Also, the slide portion 3 and sensor 16 provided on this hand
When attaching the gripped member to another member, Z
It also has the effect of acting as an axial safety sensor.

Next, other embodiments will be explained.

Although a non-contact type sensor is used as the sensor in the above embodiment, this sensor may be a contact type sensor.

Further, in the above embodiment, a sliding part is provided in the mounting part, and the displacement of the sliding body of this sliding part is detected by a sensor to detect the position of the member in the Z-axis direction. The hand may be formed so as to be directly fixed to the gripping part and detecting the position of the member in the Z-axis direction without using a sliding part.

[Effects of the Invention] Since the hand is equipped with a visual device that detects the position of the member on the XY plane and a sensor that sends a signal that causes the robot control circuit to detect the position in the Z-axis direction perpendicular to the XY plane, It is possible to reliably grasp not only correctly stacked components but also components that are three-dimensionally misaligned, and components with different heights in the Z-axis direction can be grasped with the same hand, making it possible to use a single camera. The drawbacks of conventional robots equipped with this can be completely eliminated.

Also, this hand is a normal hand with one visual device and one sensor added, so
It can be formed into a lightweight structure without sacrificing payload.

Further, the sensor not only detects the position of the member in the Z-axis direction, but also can be used as a safety sensor in the Z-axis direction when attaching the gripped member to another member.

[Brief explanation of drawings]

The drawing is a perspective view showing an embodiment of the invention. 1... Robot's arm, 3... Slide part, 4...
...Mounting part, 6...Fixed body, 7...Sliding body, 9
... Compression coil spring, 11 ... Gripping section, 12 ...
Claws, 15...Visual device, 16...Sensor.

Claims (1)

[Claims] 1. A gripping device having a gripping part for gripping a member and a mounting part attached to a robot arm to support the gripping part, and a gripping device having a visual direction attached to the mounting part to detect the gripping position of the member on the XY plane. A visual device, a slide body that is integrated with the gripping section and slides while being elastically biased in the Z-axis direction upon contact with the member or the stand on which the member is placed, and detecting the movement of the slide body. A robot hand comprising: a sensor, and a detection signal from the sensor causes the robot arm to stop forward movement in the Z-axis direction.