JP3373567B2 - Position learning device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to means for making a robot learn the position of a work to be worked.

[0002]

2. Description of the Related Art In the work using a robot, it is often necessary to set a reference point on a work to be worked and to let the robot learn the position of the reference point.

As a method for this purpose, for example, a reference point position may be calculated mathematically and set as coordinate values in the robot controller.

Alternatively, it is conceivable that the operator actually guides the robot to a reference point position by using a joystick or the like and learns the position of the robot when the reference point is reached as the reference point position.

[0005]

However, in the former method, since it is necessary to perform coordinate calculation in advance, whenever the reference point changes, complicated calculation must be redone and the reference point may move. It was not practical for some tasks.

According to the latter method, such a problem does not occur, but there is a problem that the operation of accurately guiding the robot to the reference point requires skill and the operation takes time.
Furthermore, although the position of the reference point can be learned by this method, the inclination direction and inclination angle of the work around the reference point cannot be learned.

The present invention has been made to solve the above problems, and an object thereof is to facilitate the learning of the position of a reference point on a work and to detect the inclination angle of the work around the reference point.

[0008]

According to the first invention,
A position learning device that allows a robot having a function of detecting the current position to learn the position of an arbitrary reference point set on a work, and is supported rotatably around a horizontal axis and a vertical axis to aim at the reference point. Aiming means, means for detecting the angle of the aiming axis of the aiming means aiming at the reference point, means for causing the robot to approach the work along the aiming axis based on the detected angle, and the robot and the work approaching the work It is provided with a proximity sensor for detecting a distance on the sighting axis, and means for calculating the position of the reference point from the distance detected by the proximity sensor and the position of the robot detected at that time.

In the second aspect of the invention, the aiming means is constituted by a laser emitting device for irradiating a visible laser beam.

According to the third aspect of the invention, the position from the reference point position is
By rotating the dome, the difference from the reference point
Both proximity distances to two workpieces
Based on the means to detect and the distance to the work separate point
Including the method to calculate the coordinates of each work point and the reference point.
These three points are formed from the three measured coordinate values.
It has a tilt learning function consisting of means for calculating the tilt of the work plane .

[0011]

According to the first aspect of the invention, after the aiming means has aimed the reference point, the approaching means causes the robot to approach the work along the aiming axis, so that the approaching movement of the robot to the work does not depend on manual operation. Can be done automatically. When the robot approaches the work and the proximity sensor detects the distance to the reference point of the work, the robot stops, and the position of the reference point is calculated from the current position of the robot detected at the stop position and the detection distance of the proximity sensor. Is calculated.

In the second aspect of the invention, since the aiming means is constituted by visible laser emission, the reference point is adjusted by adjusting the angle of the visible laser beam so that the mark irradiated by the laser beam on the work and the reference point coincide with each other. Can be aimed at. Therefore, it is possible to remotely operate the aiming means.

In the third invention, it is different from the reference point.
Detects the distance to at least two workpiece-specific points and
By calculating the coordinates of each point by the peak, the inclination angle of the plane formed by these three points is calculated, and the inclination angle of the work around the reference point is detected.

[0014]

1 to 3 show an embodiment of the present invention.

In FIG. 1, reference numeral 1 is a work to be worked, and a robot 2 works on the work 1. In this embodiment, it is assumed that the body of the aircraft is the work 1 and that the work of the robot 2 is to remove the surface of the body.

A laser emitter 3 is installed as an aiming means at a position apart from the work 1 to some extent. The laser light emitter 3 is supported by a stand 4 standing on the ground via a holder 5. The holder 5 supports the laser light emitter 3 rotatably around a vertical axis and a horizontal axis, and
Emits a visible laser beam in a direction corresponding to these rotation angles. An angle sensor (not shown) is built in the holder 5. This angle sensor detects a rotation angle of each axis of the laser optical axis and inputs an angle signal to a controller 6 which is composed of a microcomputer.

The robot 2 has an arm 7 through a plurality of joints.
Is movably supported in three-dimensional directions, and the direction and speed of movement are controlled by signals input from the controller 6. A proximity sensor 8 is attached to the tip of the arm 7. When the proximity sensor 8 approaches the work 1 by a certain amount or more, it detects the distance to the work 1 and outputs a distance signal to the controller 6.

The robot 2 is also provided with a position sensor (not shown) which detects the current position of the tip of the arm 7 and outputs a position signal to the controller 6.

The controller 6 calculates the trajectory of the arm 7 of the robot 2 so as to drive the arm 7 of the robot 2 along the laser optical axis, based on the horizontal and vertical rotation angles of the laser optical axis input from the angle sensor of the holder 5. , And outputs a corresponding drive signal to the robot 2. Further, the position signal input from the position sensor provided in the robot 2 is fed back to the drive control of the robot 2.

Further, the controller 6 is provided with a trigger 9 for starting the driving of the robot 2.

[0021] Next a description will be given of the operation with reference to flow charts of FIGS.

In the learning work, the operator first operates the holder 5 to irradiate the reference point of the work 1 with the visible laser beam of the laser light emitter 3 (S1).

As a result, the angle signal is input to the controller 6 from the angle sensor incorporated in the holder, and the controller 6 calculates the trajectory of the optical axis of the laser beam (S2), that is, the horizontal direction of the laser beam obtained from the angle signal. Using the function KINpantilt (THETA_pan, THETA_tilt) based on the tilt angle THETA_pan in the vertical direction and the tilt angle THETA_tilt in the vertical direction, the coordinate value TRAJ_pt and the unit vector TRAJ_vec on the coordinate system based on the trajectory of the laser beam are obtained. .

Although it is possible to aim the reference point using a surveying instrument such as a theodolite, the operator can use the sighting means 3 of the visible laser beam as in this embodiment. The aiming work can be performed at a position away from.

When the operator switches the trigger 9 to the ON position, the controller 6 moves the arm 7 of the robot 2 to the position immediately before the laser emitter 3 and the proximity sensor 8
The distance detection direction of the laser beam to the orbit of the laser beam (S
3).

For that purpose, the controller 6 first sets TRAJ_vec in the drive direction angle ROBOT_orient of the arm 7 and sets the starting point of the trajectory in the position ROBOT_pos of the arm 7. Then, the arm 7 is arranged immediately in front of the laser light emitter 3, and the angles of the joints of the robot 2 necessary to make the distance detection direction of the proximity sensor 8 coincide with the trajectory are inverse functions INVKIN (ROBOY_
pos, ROBOT_orient). By bending the joint to the angle thus obtained, the initial position and direction of the arm 7 are controlled.

Next, the controller 6 drives the arm 7 toward the work 1 along the track (S4).

Here, the current coordinates of the arm 7 ROBOT_po
The coordinate ROBOT_pos of the position to be moved next to the arm 7 is obtained by adding the coordinate change amount DELTA_pos to s. The angle of each joint of the robot 2 is calculated by the above-mentioned inverse function INVKIN (ROBOY_pos, ROBOT_orient) based on the new coordinate ROBOT_pos thus obtained, and the arm 7 is driven so as to obtain the obtained joint angle. As a result, the arm 7 approaches the work 1 along the trajectory of the laser light.

The controller 6 reads the input signal from the proximity sensor 8 in parallel with the driving of the arm 7 and determines whether or not the proximity sensor 8 has detected the work 1 (S5).
This is determined when the input signal from the proximity sensor 8 changes from an error to a numerical value indicating the distance.

The steps S4 and S5 are repeated until the input signal from the proximity sensor 8 shows the above change.

The controller 6 stops the arm 7 when the input signal from the proximity sensor 8 becomes a numerical value (S6).
Then, based on the distance PS to the reference point on the work 1 detected by the proximity sensor 8 at this position and the current position of the tip of the arm 7 which is signal-input from the position sensor of the arm 7, the coordinate POS_des of the reference point is calculated as follows. Calculated and stored in internal memory.

[0032] POS_des = ROBOT_pos + (PS × ROBOT_orient) With the above, the position learning of the reference point is completed.

Next, the controller 6 slightly rotates the arm 7 at the stop position, detects the distance to another point on the work 1 by the proximity sensor 8, and calculates the coordinates of that point (S8).

That is, the current movement direction angle of the arm 7
A new movement direction angle ROBOT_orient is determined by adding the change amount DELTA2_orient of the movement direction angle to ROBOT_orient. And the inverse function INVKIN (ROBOT_pos, ROBOT_orien
The required joint angle ROBOT_angles of the robot 2 is obtained by t), and the robot 2 is driven to the obtained joint angle. Since the tip of the arm 7 (the proximity sensor 8) is rotated without moving from the stop position, the coordinate value ROBOT_pos
Is immutable.

In this way, based on the distance PS to another point of the work 1 detected by the proximity sensor 8 at the new rotation position, the coordinate value POS_2 of this point is calculated by the following formula.

POS_2 = ROBOT_pos + (PS × ROBOT_orient) Furthermore, the tip of the arm 7 is rotated in different directions, and similar distance detection and calculation of the coordinate POS_3 regarding at least one other point are performed (S9).

With this, the distances to the three points of the work 1 including the reference points are measured, and the inclination OR of the plane formed by these three points is calculated based on the calculated coordinate values of the respective points.
IENT_des is calculated by the function KIN (POS_des, POS_2, POS_3) (S10). The calculation result is stored in the memory of the controller 6.

In this learning, if the arm 7 is rotated on the same vertical plane, the measurement points do not form a triangle, so that the arm 7 should not be rotated on the same vertical plane.
Set LTA2_orient and DELTA3_orient.

In this way, the position of the reference point and the inclination of the work 1 around the reference point can be learned. In this learning process, the operation by the operator is only to irradiate the reference point of the work 1 with the laser beam and to switch the trigger 9 to the ON position.

That is, since the controller 7 automatically guides the arm 7 of the robot 2 and the operator does not have to manually guide the arm 7, the work load on the operator is small, and the reference can be made easily and in a short time. The point position can be learned.

Further, not only the position of the reference point but also the inclination of the surrounding can be learned.

Therefore, it is possible to teach the robot 2 the starting point of the painting and peeling work of the aircraft and the inclination of the peripheral portion in a short time, and the actual work by the robot 2 can be started quickly.

Regarding the learning of the inclination around the reference point, instead of rotating the tip of the arm 7 as in the above-described embodiment, another tip is moved by moving the tip of the arm 7 to the outside of the orbit of the laser beam. You may perform the measurement regarding a point.

[0044]

As described above, according to the present invention, the means for aiming the reference point on the work, the means for driving the robot toward the work along the aiming axis, and the distance between the robot at the close position and the work are determined. Since the robot is equipped with a proximity sensor for detection and a means for calculating the position of the reference point from the current position of the robot and the distance to the work detected by the proximity sensor, the robot can be aimed substantially only at the reference point on the work. Can learn the position of the reference point. Therefore, learning of the reference point position becomes easy.

Further, by using a visible laser emitting device as the aiming means, aiming from a remote position becomes possible, and the labor required for learning is reduced.

Furthermore, at least two different from the reference point
The distance to the work-specific point is detected and
By calculating the target, the inclination angle of the work around the reference point can be detected, and the ability to collect information necessary for the work by the robot is improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a position detection device showing an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the controller.

FIG. 3 is a flowchart similarly illustrating the operation of the controller.

[Explanation of symbols]

1 work 2 robots 3 Laser emitter 5 holder 6 controller 7 arms 8 Proximity sensor

Continuation of the front page (56) Bibliographical reference 1-155502 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G05B 19/18-19/46 B25J 3/00-3 / 04 B25J 9/10-9/22 B25J 13/00-13/08 B25J 19/02-19/06

Claims (3)

(57) [Claims] 1. A position learning device that causes a robot having a function of detecting a current position to learn an arbitrary reference point position set on a work, rotates about a horizontal axis and a vertical axis to aim at the reference point. A possible supported aiming means,
A means for detecting the angle of the aiming axis of the aiming means aiming at the reference point, a means for causing the robot to approach the work along the aiming axis based on the detected angle, and a robot for approaching the work on the aiming axis of the robot and the work. A proximity sensor that detects distance,
A position learning device comprising: means for calculating the position of a reference point from the distance detected by the proximity sensor and the position of the robot detected at that time. 2. The position learning device according to claim 1, wherein the aiming means is a laser light emitter for irradiating a visible laser beam. 3. Rotating an arm from a reference point position
Therefore, at least two workpiece separate areas different from the reference point
Based on the means to detect the distance to the point by the proximity sensor and the distance to the point for each workpiece,
Measured 3 including the means to calculate the coordinates and the reference point
From the coordinate values of, the inclination of the work plane formed by these three points
The position learning device according to claim 1, further comprising a tilt learning function including a means for calculating