JPH0229807A - Correction data restricting system in visual sensor - Google Patents

Abstract

PURPOSE:To safely and efficiently execute robot work by transmitting only correction data in an area set up by a user to a robot control device and invalidating correction data other than that of the area to inhibit the transmission of the data. CONSTITUTION:A visual sensor 10 catches an object by a camera 22, detects the position and rotation of the object, compares the detected results with reference data and forms a difference from the reference data as correction data. The formed correction data, i.e. whether the formed correction data, i.e. parallel moving variables X, Y, Z and a rotational variable DELTAtheta are included between upper and lower limit values stored in a memory or not is discriminated, and even if one of the data is not included in said range, the data are not transmitted to the robot control device. Only when all the correction data are included in the range, the data are sent to the robot control device. Consequently, the robot does not execute dangerous operation exceeding the range between the upper and lower limit values and it is unnecessary for the robot control device side to check the correction data.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a visual sensor used as vision for a robot, and more particularly to a method for checking correction data created by the visual sensor.

Conventional technology When correcting the robot's position using a visual sensor,
The difference between the reference position agreed between the robot and the vision sensor and the position of the object detected by the vision sensor is sent to the robot controller as correction data, and the robot controller adjusts the position incrementally based on this correction data. Corrections are being made.

Conventionally, the correction data is transmitted and received between the visual sensor and the robot control device by creating the correction data with the visual sensor and transmitting the created correction data as is to the robot control device.

Then, if necessary, the correction data is checked on the robot control device side.

Problems to be Solved by the Invention When the visual sensor incorrectly detects an object due to the influence of disturbances such as light, or when the object moves out of its intended area, the robot detects the object outside the area. It may be dangerous if the visual sensor detects the object, creates correction data, and the robot operates based on the correction data, such as when the robot interferes with other objects when working on the object. .

In such a case, even if the correction data is checked on the robot control device side, checking each piece of correction data would be a rather difficult task on the robot control device side, which is not desirable.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a correction data restriction method that also checks correction data in a visual sensor.

Means for Solving the Problems The present invention detects the positional deviation and rotational deviation of the object from the reference position from the taught reference data and the detected object, creates position data and rotation data, and uses the detected object as correction data. The upper and lower limits of each correction data are set and stored in advance in the visual sensor that is sent to the robot control device, and the robot is controlled as correction data only when the created correction data is within the above upper and lower limits. The above problem was solved by configuring the data to be transmitted to the device.

In the working visual sensor, as in the past, an object is captured by a camera, the position and rotation of the object is detected, compared with reference data, and the difference with the reference data is created as correction data. Then, it is determined whether the created correction data, that is, the amounts of parallel movement ΔX, ΔY, ΔZ and the amount of rotation Δθ, are within the upper and lower limits stored in the memory. This correction data is not sent to the robot control device unless it is within the range, and the correction data is sent to the robot control device only when all correction data items are within the upper and lower limit values. As a result, the robot does not perform dangerous operations that exceed the upper or lower limit values, and there is no need to check correction data on the robot control device side.

Embodiment FIG. 2 is a block diagram of main parts of a visual sensor system according to an embodiment of the present invention.

In the figure, 10 is an image central processing unit, and the image central processing unit 10 is a main central processing unit (hereinafter referred to as main CPU) 1.
1, and the main CPU 11 includes a camera interface 129 and an image processing processor 13. Console interface 141 Communication interface 15. Monitor interface 16° frame memory 17. A control software memory 1B formed of ROM, a program memory 19 formed of RAM, etc. A data memory 20 composed of non-volatile RAM is connected via a bus 21.

A camera 22 for photographing objects such as parts is connected to the camera interface 12, and the image captured in the field of view of the camera 22 is converted into a gray scale image and stored in the frame memory 17.

The image processing processor 13 processes the image stored in the frame memory 17 and identifies the position of the object.

Measure your posture.

A console 23 is connected to the console interface 14, and the console 23 has a liquid crystal display, various command keys, application program input 1 editing,
It has numeric keys for performing operations such as registration and execution, and the liquid crystal display section can display menus for setting various data, a list of programs, etc.

In addition, the main CPU is stored in the control software memory 18.
A control program for U11 to control the visual sensor system is stored, and a program created by the user is stored in the program memory 19.

A system using the visual sensor system, such as a robot, is connected to the communication interface 15. Also,
A monitor television 24 that displays images taken by the camera 22 is connected to the TV monitor interface 16.

The above configuration is similar to the configuration of a conventional visual sensor system, and in the present invention, the data memory 20 stores the upper and lower limit values of correction data that the visual sensor 10 sends to the robot control device. This is different from conventional visual sensor systems.

Correction data for robots can be broadly classified into the following two types.

(1) Point position correction data The difference between the position of the object detected by the visual sensor and the reference position. The amount of movement of the position of the detected object relative to the object (ΔX, ΔY).

ΔZ) and the rotation amount Δθ of the object. In addition, upon receiving the movement amount (ΔX, ΔY, ΔZ) of this correction data and the rotation amount Δθ, the robot incrementally corrects the tool center point by the received movement amount from the reference position, and the rotation amount Δθ
The wrist axis will be rotated from the reference position by the same amount.

(2) Coordinate correction data In the sensor coordinate system, a reference coordinate system is set by teaching three reference points, and the coordinate system in which the visual sensor captures the object is moved from the above coordinate system fi. (ΔX,
ΔY, ΔZ) and the three-dimensional rotation amount Δθ of that coordinate system from the reference coordinate system. In this case, since it is a coordinate system transformation,
This correction data will be sent to the robot controller in the form of a transformation matrix.

Note that the point position correction data in (1) above is like a special solution to the coordinate correction data method in (2) above.
According to the coordinate correction data method of (1), the point position correction data of (1) is also included.

Among the above correction data, the point position correction data (1) is based on the movement m(Δ
X, ΔY, ΔZ) and the rotation amount Δθ of the object (wrist axis), it is easy to limit the correction data by setting an allowable upper limit value and an allowable lower limit value for each item.

However, when the correction data is the coordinate correction data described in (2) above, the three-dimensional rotation amount Δθ of the coordinate system is generally difficult to grasp numerically. However, three-dimensional rotation has a certain principal axis that is the center of rotation, and can be replaced by rotation around this principal axis. Therefore, in the present invention, the allowable upper and lower limits of the amount of rotation around the main axis are set, and the correction data is limited by the rotation around the main axis.

Therefore, first, each @ in the sensor coordinate system of the correction data
The allowable upper and lower limits of (X, Y, Z) and the allowable amount of rotation around the main axis (the rotation opening around the main axis is also the amount of rotation in the point position correction data in (1) above) are stored in the data memory 20 in advance. Set it.

Then, each time a snap command is input from the robot control device via the communication interface 15, the visual sensor 10 starts the process shown in FIG.

First, the CPU 11 outputs a snap command to the camera 22 via the camera interface 12, performs grayscale gradation processing on the snapped image by the image processing processor 13, and then stores the image in the frame memory 17 ( Step 81).

Next, CPtJll outputs a target object detection command to the image processing processor 13, and upon receiving the command, the image processing processor 13 performs image analysis processing on the image stored in the frame memory 17 to recognize the target object. , detecting the position (e.g. center position) and orientation (rotation) of the target object (
Step 82.83). Next, the detected camera coordinate system (
The position and amount of rotation of the object on the sensor coordinate system, which is a spatial coordinate system shared by the visual sensor 10 and the robot, are determined from the position and orientation of the pixel value data of the frame memory 17. Differences between the reference data of the reference position and rotation amount are determined, and correction data is created. The correction data obtained in this way is applied to the amount of parallel movement of each axis (ΔX,
(ΔY, ΔZ) and rotation jΔθ (if the correction data is the point position correction data of (1) mentioned above, the movement amount ΔX).

ΔY, Δ21 rotational suspension Δθ are obtained as the correction data itself, and if it is the coordinate correction data of 2) mentioned above, the correction data is obtained in the form of a transformation matrix of coordinate transformation, so the rotation amount of this transformation matrix The amount of rotation of the main shaft is determined from a matrix of 3 rows and 3 columns showing . Note that the amount of parallel movement is obtained from the position vector portion of the transformation matrix (step 84).

It is determined whether or not the obtained correction apertures ΔX, ΔY, Δ2, and Δθ are within the set range between the allowable upper limit value and the allowable lower limit value set in the data memory 19 (step S5), and if within the set range, The correction data obtained in step S4 is transmitted to the robot control device via the communication interface 15 (step S6). Furthermore, if it is not within the set area, the correction data is not transmitted and the process ends.

Effects of the Invention The present invention transmits only the correction data within the area set by the user to the robot control device, invalidates the correction data outside the area, and prevents the correction data from being sent. This can be prevented, and since objects such as abnormally shaped workpieces are ignored, the robot can work safely and efficiently.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of an embodiment of the present invention, and FIG. 2 is a block diagram of a main part of a visual sensor system according to the same embodiment. 10...Visual sensor, 22...Camera, 23...
Console, 24...Monitor TV.

Claims (1)

[Claims] The visual sensor detects the positional deviation and rotational deviation of the object from the reference position based on the taught reference data and the detected object, creates position data and rotation data, and sends it to the robot control device as correction data. Correction in a visual sensor in which the upper and lower limit values of correction data are set and stored in advance, and the created correction data is sent to the robot control device as correction data only when it is within the above upper and lower limit values. Data restriction method.