JPH0197590A - Detector for quantity of gravity positional displacement of robot - Google Patents

Abstract

PURPOSE: To detect the displacement of a hand due to the weight of a workpiece with ease by providing a means to calculate the displacement due to workpiece weight from the difference between the position of a camera while no workpiece is gripped and that while a workpiece is gripped. CONSTITUTION: While gripping no workpiece W including wheels, a hand H is moved to the position where a camera means 2 sights its reference point, this position of which camera means 2 relative to the reference point is read in a central processing unit 6 by an operation of a button 7. While gripping any workpiece W, the hand H is moved to a predetermined position, where the position θ1 of the camera means 2 relative to the reference point is read into the central processing unit 6 likewise. The central processing unit 6 calculates the difference between these two relative positions thus read in to compute the displacement (d) of the hand H due to the weight of the workpiece W from this difference.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gravitational position deviation detection device for a robot.
More specifically, the present invention relates to a device that detects the magnitude of positional deviation that occurs when a robot hand holds a heavy object.

[Prior art]

Examples of conventional automobile assembly robots are shown in Figures 3 and 41.
! Shown in l.

This robot 10 has wheels W mounted on a hub C on the body side of an automobile.
This is a robot for attaching wheels, and a hand H for gripping a wheel W is attached to the tip of an arm A.

When the operator operates the operating means 14 to move the hand H to a position where the central axes t and h of the hand H and the central axis Lc of the hub C substantially coincide with each other and gives a position calculation command, the central processing means 13 Read the reference point position from the processing means 12, this reference point position! is calculated by the image processing means 12 from the position of the reference point (for example, the tip of the bolt B) in the image obtained by the camera means 11, and is the relative position between the camera means 11 and the reference point.

The central processing means 13 drives the robot 10 and recognizes the spatial position of the arm A, and therefore the spatial position of the camera means 11 fixed to the arm A! gm
I'm L. Therefore, the spatial position of the camera means 11,
From the relative position of the reference point B with respect to the camera means 11, a predetermined position where the central axes t, h of the hand H and the central axis Lc of the hub C can be made coincident is calculated.

Next, the operator is the operator! When 1t14 is operated to cause the hand H to grasp the wheel W and give an instruction to attach the wheel W to the hub C, the central processing means 13 drives the robot 10 and moves the hand to the previously obtained predetermined position. Move H.

However, as shown in FIG. 3, when the wheel W is not gripped, the center axis of the hand H should be aligned with the center axis Lc of the hub C, but as shown in FIG. , wheel W
When the hand H is held by the hand H, the position of the hand H is lowered due to its weight, resulting in a positional deviation d.

Therefore, the operator visually measures the amount of positional deviation d, inputs it as an offset value from the operating means 14 into the central processing means i3, and corrects the initially obtained predetermined position.

[Problem that the invention seeks to solve]

There is a problem in that it takes time and effort for an operator to measure and input the positional deviation that occurs when a robot's hand grips an object, making the operation complicated. Additionally, there are limits to accuracy and reliability.

Therefore, it is an object of the present invention to provide a gravity displacement amount detection device for a robot that automatically detects the amount of displacement when the heavy object is gripped.

[Means for solving problems]

The gravitational position deviation amount detection device for a robot according to the present invention includes a camera means attached near the hand of the robot, and a camera position calculation means for calculating the relative position of the camera means with respect to the reference point from the position of the reference point seen by the camera means. Then, the workpiece is determined from the difference between the camera position obtained by moving the arm to a predetermined position without gripping the workpiece with the hand and the camera position obtained by moving the arm to the predetermined position with the workpiece gripped by the hand. A structural feature of this device is that it includes a positional deviation amount calculation means for calculating the amount of positional deviation due to weight.

[Effect]

The relative position of the camera means with respect to the reference point is obtained by moving the hand to a predetermined position where the reference point can be seen by the camera means without gripping the workpiece.Next, the hand is moved to the predetermined position with the workpiece gripped. moving to obtain the relative position of the camera means with respect to the reference point. If the difference between the relative positions of the two is calculated, the difference is nothing but the amount of positional deviation caused in the hand due to the weight of the workpiece.

Therefore, the burden on the operator is reduced, and the amount of positional deviation can be detected with high precision and reliability.

Furthermore, since the amount of positional deviation obtained in this way can be directly taken in as the amount of offset, it is possible to save the operator's effort to input it for correction.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on the embodiment shown in the figures. Here, Fig. 1 shows the configuration of a robot device including a gravitational position deviation amount detection device according to an embodiment of the present invention in a state in which a workpiece is not gripped. The conceptual diagram, FIG. 2, is a diagram equivalent to FIG. 1 in a state in which a workpiece is gripped. Note that the present invention is not limited to the following examples.

1st y! In J, robot 10. camera means 11;
The image processing means 12 and the operation means 14 have the same structure as conventionally known, and are given the same reference numerals as in FIGS. 3 and 4.

Although the central processing means 6 includes the functions of the conventional central processing means 13, it is given a different reference number because it includes a function that becomes a part of the gravity position shift amount detection device 1 according to the present invention.

Now, the gravitational position deviation amount detection device l includes a camera means 2,
It is composed of an image processing means 5, a central processing means 6, a first reading button, and a second reading button 8.

The camera means 2 is mounted on a mounting member 3 extending from a mounting member 3 that can be freely attached to and detached from the hand H! It is installed on 4.

The mounting member 3 may be made of a magnet, for example.

The image processing means 5 calculates the relative position of the camera means 2 with respect to a reference point (for example, the tip of the bolt B) from the image obtained by the camera means 2, and inputs the calculated position to the central processing means 6 as the camera position.

The operator operates the operating means 14 to move the hand H to a position where the center axis of the hand I (and the center axis Lc of the hub C substantially coincide with each other), and when a reading command is given from the operating means 14, the center The processing means 6 obtains the relative position of the reference point and the camera means 11 using the same function as the conventional one, and calculates the center axis and L from the relative position and the current position of the robot 10.
Calculate the position where c matches.

In this state, when the operator 7 presses the first reading button 7, the central processing means 6 determines the relative position θ between the reference point and the camera means 2. is read from the image processing means 5. FIG. 1 shows this state.

Next, the operator operates the operating means 4 to cause the hand H to grip the wheel W and move the hand H to the previously calculated position. This position is the center axis 1 when the wheel W is not gripped. This is the position where = and Lc match, but the wheel W
Because it is gripped, its weight causes a positional deviation d, which causes the center axis to shift.

and LC do not match, and FIG. 2 represents this state.

Here, when the operator presses the second read button 8, the central processing means 6 reads the reference position and the relative position θl of the camera hand from the image processing means 5, and then uses the previously obtained relative position θ. The difference θ.

Calculate -0 ward. This difference θ. −08 is a value corresponding to the positional deviation amount d.

Thus, the central processing means 6 calculates the difference θ. The positional deviation amount d can be obtained from -01. The obtained positional deviation amount d is
It is added as an offset value for the first calculated position (the position where the center axis and Lc match when the wheel W is not gripped), and this is the offset value for the position where the m force is corrected (the position where the wheel W is not gripped).
A position λ where the center axis th and Le coincide with each other is obtained when the gripper is held.

Once the positional deviation amount d has been obtained and corrected, the mounting member 3 is removed from the hand H and the camera means 2 is removed.

In the actual installation work, first, the relative position of the hub C with respect to the camera means 11 is obtained by the camera means 11 and the image processing means 12, and the hand H that fits the position of the hub C is obtained from the relative position and the current position of the robot 10. The robot 10 is driven to calculate the corrected position by adding the positional deviation amount d to the calculated position, and after gripping the wheel W, moves the hand H to the corrected position. As a result,
The positional deviation of the hub C with respect to the robot 10 (setting positional deviation) and the positional deviation of the hand H due to the weight of the wheel W (1 [I direction positional deviation)] are corrected, and the wheel W can be suitably mounted. .

〔Effect of the invention〕

According to the present invention, a camera means attached near the hand of the robot, a camera position calculation means for calculating the relative position of the camera means with respect to the reference point from the position of the reference point seen by the camera means, and a workpiece gripped by the hand. Calculate the amount of positional deviation due to the weight of the workpiece from the difference between the camera position obtained by moving the arm to the predetermined position with the hand holding the workpiece and the camera position obtained by moving the arm to the predetermined position with the hand gripping the workpiece. There is provided a gravitational positional deviation amount detection device for a robot, characterized in that it is equipped with a positional deviation amount calculation means for calculating the amount of positional deviation, thereby making it possible to easily detect the positional deviation of a hand due to the weight of a workpiece. Therefore, even if the workpiece is heavy, installation work etc. can be carried out suitably.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of the configuration of a robot device including a gravitational position deviation detection device according to an embodiment of the present invention in a state in which a workpiece is not gripped, and FIG.
'Fl! FIG. 3 is a conceptual diagram of the structure of a conventional robot device in a state in which a workpiece is not held, and FIG. 4 is a conceptual diagram of the structure of a conventional robot device in a state in which a workpiece is gripped. [Explanation of symbols] 1... Robot gravity position deviation detection device 2... Camera means 3... Mounting member 5... Image processing means 6... Central processing means 7... First Read button 8...Second read button IO...Robot 11...Camera means 12
...Image processing means 14...Operation means W...Wheel A...Arm H...Hand
C...Hub B...Pol) d.
...Positional deviation amount θ. ...Relative position θ1 when the workpiece is not gripped...Relative position when the workpiece is gripped. Applicant Daihatsu Motor Co., Ltd.

Claims (1)

[Claims] 1. A camera means attached near the hand of the robot, a camera position calculation means for calculating the relative position of the camera means with respect to the reference point from the position of the reference point seen by the camera means, and a camera means attached to the arm when the hand is not gripping the workpiece. The amount of positional deviation is calculated from the difference between the camera position obtained by moving the arm to a predetermined position and the camera position obtained by moving the arm to the predetermined position while holding the workpiece with the hand.The amount of positional deviation due to the weight of the workpiece is calculated. What is claimed is: 1. A robot gravitational position deviation detection device, characterized in that it is equipped with a calculation means.