JPH068130A - Automatic buffing method by robot - Google Patents

Abstract

PURPOSE:To provide an automatic buffing method wherein a position of a robot hand is automatically corrected for buffing, when a work is held by a robot to perform buffing, in buffing a front grille for an automobile. CONSTITUTION:This is a method using a perpendicular articulated robot to automatically perform buffing. An offset signal is issued to a robot, correction of a robot hand position is performed to strongly press a work, and perform buffing in order to keep polishing force constant when an electric current value is lower than a fixed value, in a buffing method wherein a work 4 is gripped by a robot 1, press-contacted with a buff 2a for polishing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic buffing method for performing buffing using a vertical articulated robot.

[0002]

2. Description of the Related Art A work fixing system is used as an automatic method for buffing a work. However, in the work fixing method, the buff is held by the robot hand, and the buff diameter and the number of rotations are limited due to the loadable weight of the robot, and the work moving method is used.

[0003]

Regarding the buffing of the front grill for an automobile, an operator is currently pushing it against the buff by hand to polish it, or as an automated method, the width of the window frame for the automobile is small, Moreover, because of the frame shape, the work is held by the robot hand by the work moving method,
When performing buffing, there is a problem in that the buff diameter becomes smaller due to friction and cannot be accurately and uniformly buffed.

The present invention is technically directed to an automatic buffing method for automatically correcting the position of a robot hand when performing buffing while holding a work on a robot in buffing a front grill for an automobile. This is an issue.

[0005]

[Means for Solving the Problems] The technical means taken to solve the problems are as follows. That is, in the buffing method in which a vertical articulated robot grips a work and pushes it against a buff that rotates with a motor to polish the buff, the buff is pressed to keep the force of pushing the work constant. When the current value of the rotating motor is less than a certain value, an offset command signal is issued to the robot, and the robot receives the signal, and the buff position is automatically corrected at teaching points provided at multiple positions on the workpiece. Then, it is an automatic buffing method by a robot in which the current value of the motor is set to a certain value or more.

[0006]

If the current value of the motor is above a certain level, the load is applied to the motor and the work is sufficiently polished. When the buffing is sequentially performed, and the diameter of the buff is reduced by abrasion, the current value becomes a certain value or less, which means that the buffing is not sufficiently performed.

Therefore, by controlling the electric current value to a certain value or more at a predetermined teaching point of the work, the contact between the buff and the work becomes constantly constant, and the buff can be polished accurately.

[0008]

EXAMPLE This example will be described below.

FIG. 1 is a block diagram of the present invention, in which 1 is a vertical articulated robot, 2 is a motor device having a spindle motor and a shaft 2b for rotating a buff 2a, and 2c is an ammeter. The value determines the load status of the motor. Reference numeral 3 is a control device of the robot 1.

FIG. 3 shows the shape of the work. Reference numeral 4 is a front grill for an automobile, and the front grill (hereinafter referred to as a work) shown in FIG. 3B is a hand 5 provided at the tip of the robot.
It is securely held by jigs (small cylinders) 6a and 6b.

The articulated robot shown in FIG. 1 (six motors for rotating each axis are built-in, the movement is shown by arrows) is provided with a work 4 attached to the tip thereof and buffed by a buff 2a.

The buff has a diameter of 300 mm, and if about 10 buffs of the work 4 are buffed, the diameter will be worn by about 0.5 mm, and it is necessary to correct the position of the robot hand. FIG. 2 shows the relationship between the number of times a work is polished and the buff diameter. Next, a method for buffing a work will be described.

(1) The work 4 is attached to the hand provided at the tip 1a of the articulated robot 1, and the work 4 is pressed against the buff 2a by the predetermined robot teaching to finish the surface of the work.

(2) The robot 1 sequentially performs buffing on the surface of the work according to a teaching instruction from the robot control device 3, and the buffing process proceeds in the direction of the arrow shown in FIG.

(3) After the automatic buffing is completed by the work robot, the work returns to the fixed position. Next, the next work is fixed to the hand, and the same operation is performed.

(4) Motor device 2 during buffing of work
If the ammeter of (1) becomes a certain value (for example, 5 Amp) or less, the load of the motor is small, and therefore the pressing pressure between the work 4 and the buff 2a is small, so that the buffing is not sufficiently performed.

Therefore, in this case, the control device 3 issues an offset command signal to the robot 1, whereby the work and the buff are strongly pressed and buff polishing is performed.

In this way, it is possible to maintain the constant value of the current and to constantly make the polishing force of the buff constant.

(5) The fixed point for measuring the current value is measured at points A1, A2, ... An of the work as shown in a part of FIG. 4 to correct the position of the robot hand.

The work is buffed by the above method, and deburring work is also possible.

FIG. 5 (a) shows the direction in which the buff is pressed against the work, and FIG. 5 (b) shows the situation when the work is moved up and down. The buff is placed in TOOL1 (angle α1 = 10).
°), TOOL2 (α2 = 20 °), TOOL3 (α3
= 30 °), TOOL4 (α4 = 40 °), TOOL5
It is divided into (α5 = 50 °) and moved in the direction of TOOL1 → TOOL5 to perform buffing.

The number of divisions of the buff varies depending on the buff diameter, the use angle, etc., but is set so that the offset positional deviation error with respect to the buff is 0.1 mm or less.

In order to simplify the setting of the tool coordinate setting method as shown in FIG. 5C, the tool coordinate system can be defined by only one point by aligning the direction of the robot flange surface with the buff center. .

The divided tool coordinate system is assigned to each point, and a group of points A1, A2, ...
An is provided, the buff diameter is detected and the change in the buff's rotational torque is measured at this position. When the current value falls below a certain value, each point is assigned and corrected by applying an offset in the tool coordinate system. To do.

In the above embodiment, the work is described as a front grill for an automobile, but the present invention is not limited to this, and it can be applied to all those requiring buffing.

[0026]

The present invention has the following effects.

1. A simple position correction function enables automatic correction of the buff diameter.

2. Teaching time can be greatly reduced because the tool coordinate system can be easily set.

3. The quality can be made uniform by the automatic offset from the measured value of the buff rotation torque.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of the present invention.

FIG. 2 is a diagram showing a relationship between a buff system and the number of polishings.

FIG. 3A is an explanatory view of a work, FIG. 3A shows a front grill for a vehicle, and FIG. 3B shows a method for supporting a hand of the work;
(C) is a sectional view of (b).

FIG. 4 is an enlarged external view of a part of the work.

5A and 5B are views showing a relationship between a work and a hub, FIG. 5A is an explanatory view of pressing a work toward a center of a buff, FIG. 5B is an explanatory view of division of a tool coordinate system, and FIG. It is a setting diagram of a system.

[Explanation of symbols]

 1 Vertical articulated robot 2 Motor device 2a Buff 2c Ammeter 4 work

Claims (1)

[Claims] 1. In a buffing method in which a vertical articulated robot grips a work and pushes it against a buff rotating by a motor to polish the work, in order to make the force of pushing the work constant, When the current value of the motor that rotates the buff is less than a certain value, an offset command signal is issued to the robot, the robot receives the signal, and the buff position is automatically detected at teaching points provided at multiple positions on the workpiece. A method for automatically buffing by a robot, which is modified so that the current value of the motor is a certain value or more.