JPH0259282A - Correcting device for position of robot - Google Patents

Abstract

PURPOSE:To correctly perform a deburring finish work by operating the displacement of a work by detecting and measuring the dispersion of the position caused by the slippages of the work position and work itself by a distance sensor and forming the structure correcting the operation of a robot based on this displacement. CONSTITUTION:The distance sensor 2 attached to the terminal of the robot 1 equipped with a robot control device 7 is connected to the position correcting device 4 equipped with a display device 3, a memory device 5 and an input device 6 are connected to this position correction device 4 and the robot control device 7 and position correction device 4 are connected by a communication interface 8. By this structure, the slippage can be corrected by the position correction device 4 by measuring by the distance sensor 2 the slippage due to the position of the work placed as per a deburring work and the dispersion of the work itself, for instance. Even the dispersion of the work itself can be removed by grinding with the tool attached to the terminal of a robot 1 and also the work operation range to the robot 1 can be enlarged.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is directed to, for example, finishing the casting product (workpiece) by grinding and finishing it by using a distance sensor to remove variations and cracks during the casting process. The present invention relates to a robot position correction device.

(Prior Art) In general, when this type of robot performs tlf cutting work on a workpiece, operation data (robot operation order and robot operation position) is taught (input) to the robot control device in advance. Normal teaching work is performed on a standard work (a standard work formed based on a design drawing, also called a master work).

(Problem to be Solved by the Invention) However, when the above-mentioned robot performs actual grinding work on a workpiece, it exchanges the workpiece and grinds another workpiece each time, so the position where the workpiece is placed varies. Deburring work on workpieces such as cast products is difficult due to variations in the casting process, so even if you drive the robot using only the movement data taught to the master work,
It is difficult to grind and finish the above-mentioned workpiece with high precision.

In other words, it is conceivable that the conventional grinding work means using a robot incorporates a visual detection device and uses this visual detection device to detect the position of the workpiece and correct the position of the workpiece. Misalignment of the shape of the workpiece itself occurs irregularly and three-dimensionally, and due to the work environment such as lighting and the material and shape of the workpiece, it is difficult to use the robot with high accuracy using the visual detection device mentioned above. Grinding and finishing work is difficult.

On the other hand, as a method for grinding by a robot, a method has been proposed in which a strain sensor, a force sensor, etc. are attached to the robot's hand, and the robot position is corrected by feedback from the force sensor. Since the reaction force (force for pressing) is kept constant and controlled by the feedback amount of However, there are drawbacks such as the risk of grinding and removing areas that do not require deburring.

The present invention has been made in view of the above-mentioned circumstances, and includes a distance sensor attached to the hand of a robot, and this distance sensor detects variations in the position where the workpiece is placed and the position caused by the shift due to the workpiece itself. By correcting the amount of deviation of the workpiece using the movement data taught to the robot, the grinding tool at the robot's hand is adjusted according to the work data taught to the grinding tool on the workpiece surface with particles attached. It is an object of the present invention to provide a position correction device for a robot that operates to accurately perform deburring work, etc.

[Structure of the invention]

(Means for solving the problems and their effects) The present invention includes:
A distance sensor is attached to the hand of a robot equipped with a robot control device, the distance sensor is connected to a position correction device equipped with a display device, a memory device and an input device are connected to the position correction device, and the robot control device and a position correction device are connected through a communication interface, and the distance sensor detects and measures the positional variation caused by the deviation between the workpiece position and the workpiece itself, and the robot calculates the position of the workpiece from the motion data taught to the memory device. The amount of deviation is calculated, and based on this amount of deviation, the previously taught motion of the robot is corrected, and this is sent to the robot control device, which then corrects the amount of deviation of the workpiece. The grinding tool is operated on the surface of the workpiece, which has a number of burrs, to accurately perform the burr removal and finishing work.

(Embodiment) Hereinafter, an illustrated embodiment in which the present invention is applied to, for example, deburring and grinding of a workpiece as a cast product will be described.

In FIGS. 1 and 2, the reference numeral 1 indicates, for example, the hand (
This robot is designed to hold a tool such as a grinder, and some of the hands of this robot 1 include:
For example, a distance sensor 2 such as an optical sensor, an electrostatic induction sensor, a dial gauge, or a potentiometer is attached, and this distance sensor 2 is connected to a position correction device 4 equipped with a display device 3 that displays characters and figures. ing.

Further, a memory device RI 15 and an input device 6 are connected to this position correction device 4, and this memory device 5 is a memory circuit that stores teaching data etc. to the robot 1, and the input device 6 is This is an input circuit that gives instructions to the position correction device 4. Further, the robot 1 is provided with a robot control device 7 to control the operation of the robot 1 itself, and the robot control device 7 and the position correction device 4 communicate with each other by, for example, a bus connection. They are connected via interface 8.

Therefore, when a workpiece is placed on a substrate (not shown) and the casting product (workpiece) itself is ground to remove variations and defects during casting, using the distance sensor 2,
The distance sensor 2 measures the deviation caused by variations in the way the work is placed and variations in the work itself. Then, the amount of deviation from the measurement data of the distance sensor 2 is detected, and based on this amount of deviation, the movement data of the robot 1 that has been previously inputted by the input device 6 and taught to the memory device 5 is corrected for the position. Corrected with device 4,
Based on the correction value (correction data) from the position correction device 4, the motion data of the robot 1 is transmitted to the robot control device 7 through the communication interface 8, and the robot control device 7 causes the robot 1 to perform the instruction as instructed. In other words, the grinder performs finishing work using a grinder.

Therefore, in the present invention, even if there are variations in the way the work is placed or in the work itself, the robot 1 can accurately perform grinding operations such as deburring based on the taught correction signal.

Next, the operation of the present invention described above will be explained based on the flowchart of FIG.

FIG. 2 is a diagram for explaining how to place a workpiece to be subjected to deburring work according to the present invention, variations occurring in the workpiece itself, and deburring process, and gl is the work of the standard workpiece (master work) Wl. g2 indicates the work surface of the actual workpiece W2 placed at a shifted position to be actually ground. Also, the code D1. D2. D3 is the robot 1 at the time of measuring the workpiece of the movement data for measuring the workpiece.
The positions of E2, E2, and E2 are shown respectively.
E3 indicates the distance and distance sensor measurement direction by the distance sensor 2 at the position of the robot 1 at the regular time of the work Ifllj. Furthermore, the symbol At.

A2. A3 is the workpiece measuring robot position D1°D2
．． D3 indicates the workpiece position measured by the distance sensor 2 on the mask workpiece W1, and the symbol B1. B
2. B3 is the workpiece measuring robot position D1. D2.
D3 indicates the workpiece position measured by the distance sensor 2 on the actual workpiece W2.

Therefore, °, the workpiece measuring robot position DI on the master workpiece Wl, D2. Position A where this master work W was measured by D3 1. A2.

■ Position C1゜C2,C where A and the actual workpiece W2 were measured
The position corresponds to 3.

Next, the relationship between the mask work W1 shown in FIG. 2 and the actual work W2 will be explained based on the flowchart shown in FIG.

In FIGS. 2 and 3, first, a master work (reference work) Wl to be worked by the robot 1 is placed within the operating range of the robot 1. As shown in FIGS.

In the first step a, the robot 1 is operated with respect to the master work Wl, and the positions aJ of the work W1 that are not to be deburred on the master work W are determined using the distance sensor 2 attached to the hand of the robot 1. Then, the measuring operation of the robot 1 is taught to the memory device 5, and the teaching data is input. In other words, the teaching data is used as the measurement operation data.

Therefore, in FIG. 2, the reference numeral D1. D2. Let D3 be the measurement point.

In the second step b, the robot 1 is operated to teach the robot 1 how to perform deburring work on the master work Wl. This teaching data is used for deburring work.

In the third step C, the measurement operation data of the first step a and the second
The operation data for the deburring operation in step b is transmitted from the robot control device 7 to the memory device 5 connected to the position correction device 4 and stored therein.

In the fourth step d, the position of the robot movement position measured by the distance sensor 2 among the robot movement positions of the measurement movement data of the first step a is made to correspond to the order in which the mask workpiece W1 is measured by the distance sensor 2. The created table is input from the input device 6 and is stored in the memory device 5. This table is a measurement position correspondence table.

In the fifth step e, the three robot operation positions measured by the distance sensor 2 and the workpiece correction surface composed of these three points are determined among the robot operation positions of the measurement operation data of the first step a. The corresponding table is inputted from the input device 6 and stored in the memory device 5. This table is a correction surface correspondence table.

In the 6th step f, the position of the robot operating position in which the workpiece W2 is the object of work among the robot operating positions of the deburring operation data in the above step b is correlated with the correction surface in the correction surface correspondence table in the 5th step e5. The created table is inputted from the input device 6 and stored in the memory device 5.
to be memorized.

This table is a working correction table.

In the seventh step g, the robot 1 is operated with respect to the master work W1 based on the measurement operation data of the first step a, and the measured distance at each Al1 fixed position measured by the distance sensor 2 is stored in the memory device. Save to 5. This measurement data is distance measurement data for the mask work W1 (in Fig. 2, A1.A on the work surface of the master work W).
2. This means that the position of A3 was measured).

Next, in the eighth step h, the mask work W1 is replaced with another work.

In the ninth step i, the robot 1 operates on the other replaced workpiece based on the measurement operation data of the first step a, and the measured distances at each measurement position measured by the distance sensor 2 are stored in the memory device 5. (In FIG. 2, the positions of B, , B2, and B3 on the work surface of the actual workpiece W2 are stored as iD.
). This measurement data is used as workpiece distance measurement data.

In the tenth step j, the master work distance M measurement data, the work distance measurement data, the deburring work operation data, the measurement operation data, the measurement position correspondence table, the correction surface target table, which are stored in the memory device 7, A correction value for the amount of deviation of the workpiece is calculated based on the work correction surface correspondence table.

The correction according to the specific example described above is performed by calculation using the following formula.

That is, the position correction device 4 calculates the measurement position on the master work W1 based on the position data of the measurement operation data, the measurement position correspondence table, and the master work distance measurement data.

Next, the position data of the robot 1 has the robot position coordinates (x, y, z) and the posture vector of the hand of the robot 1, and the measurement direction of the distance sensor 2 is as follows.
Hand posture direction vector of robot 1 and distance sensor 2
The installation position can be determined.

The measurement direction vector of this distance sensor 2 is N.

If N, N is the measurement position XT on the workpiece.

y z YT, ZT are XT-X10g-NX Y　T　-y　+　0-N　v It becomes ZT-Zl-NZ.

However, x, y, z indicate the positional relationship of the robot 1, and g
indicates the Jl constant distance of the distance sensor 2.

Also, the measurement position on the master work W1 is A I, A 2
.

If it is A3, A’-(X+, Y+, ZL) However, i=1.2.3.

Next, according to the correction surface correspondence table, the above three points A I,
A plane composed of A 2 and A a, with A1 as the origin, A2 as a point on the +X axis of the plane, and A3 in a certain direction with respect to the X axis on the plane. Find the +Y axis.

If this plane is FA, then It is expressed as

nX---(X2-Xl) n --1-(Y2-Y,) p n-de(Z2-Z,) 2g Ox-(X3-Xl)-~2 f　(X3-X1') (X2-Xl) + (Y3-Yl) *(X2-Xl) (Y2-Yl) + (Z3-21) (Z2-21) 1 0, - (Y3-Yl) -.

((X3-Xl) (X2-Xl) + (Y3-Yl) * (Y2-Yl) ('y2-y1) + (Z3-z, )(Z2-21
) ) 0□-(Z3-Z, )-feather((X3-Xl)(X2-
Xl)g (Y -Y) + (Z3-21) (Z2-21)
) ten (Y3-Yl) * (Z2-Zl) a -n 三〇 -n IIOyzz
y a mll0 LI a −OI axzzx a = n φO−n −O xyyx ~22 M −(X2−x, ) + (Y2−Yl> 2+(
Z −Z )2.

Also, for the work W2 which is different from the master work W,
The regular position 41j on the workpiece W2 is calculated based on the distance measurement data for the workpiece measured by the distance sensor 2, the measurement position correspondence table, and the position data of the nJ regular operation data.

The obtained measurement position is shown in B1. B2, Ba.

Next, according to the correction surface correspondence table, the above three points B, BB
Let 81 be the original 1 2 ′ 3 point on the plane constructed by , and let B2 be the point on the +X axis of the plane that constitutes, and the +Y axis of the plane that constitutes the direction of B3 with respect to the X axis on the plane that constitutes B2. seek what is. This plane is designated as F13.

On the other hand, the position after correction is determined as follows using the motion data for deburring work and the work correction surface correspondence table, and after the correction, the motion data for deburring work is created.

Next, the position after correction - FB - FA / the position to be corrected,
Also, robot positions that are not on the work correction surface compatible table are
After correction, it is stored as operation data for deburring work. A on the work surface of the mask work W1 corresponds to C1 on the work surface of the actual work W2, but in this correction formula, A1 on the mask work work surface corresponds to 81 on the work surface. ing.

On the other hand, since a grinder or the like is used as a tool for the deburring work, the grinder performs the grinding work so that it contacts the deburring surface as a grinding surface, and the workpiece does not shift significantly. Therefore, the deviation in the direction of the deburring surface (the distance between B and CI, that is, the horizontal distance on the work surface) can be absorbed, but the height and posture of the grinder relative to the work cannot be absorbed, so the above correction must be performed. The height and posture of the grinder relative to the workpiece can be adjusted by
You will be able to make corrections.

In this way, operation data for deburring work is created after the position is corrected and corrected when the workpiece is replaced.

In the 11th step, the operation data for deburring work is transmitted to the robot control device 7 after the correction calculated in the 10th step j. As a result, when the robot 1 is operated, the robot 1 performs the work that has been taught.

In the twelfth step Ω, by repeatedly and continuously performing the eighth step h to the eleventh step k, the deviation with respect to the workpiece is automatically corrected, and the robot 1 continuously performs the work as taught.

〔Effect of the invention〕

As described above, according to the present invention, the robot control device 7
A distance sensor 2 is attached to the hand of a robot 1 equipped with a robot 1, this distance sensor 2 is connected to a position correction device 4 equipped with a display device 3, and a memory device 5 and an input device 6 are connected to this position correction device 4. Since the robot control device 7 and the position correction device 4 are connected by a communication interface 8, the distance sensor can detect deviations due to variations in the position of the workpiece or the workpiece itself, such as in deburring work, for example. 2, and the position correction device 4 can correct the deviation 2. In addition, it is also possible to remove variations in the workpiece itself by grinding it with a tool attached to the robot's hand. It has excellent effects such as being able to expand the working range of motion.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a robot position correction device according to the present invention, FIG. 2 is a diagram for explaining, for example, a workpiece deburring operation using the robot position correction device according to the present invention, and FIG. FIG. 3 is a diagram showing a flowchart of the present invention. DESCRIPTION OF SYMBOLS 1... Robot, 2... Distance sensor, 3... Display device, 4... Position correction device, 5... Memory device, 6
...Input device, 7.Robot control device, 8.Communication ink face.

Claims (1)

[Claims] A distance sensor is attached to the hand of a robot equipped with a robot control device, the distance sensor is connected to a position correction device equipped with a display device, a memory device and an input device are connected to the position correction device, and the robot control device A position correction device for a robot, characterized in that the and the position correction device are connected through a communication interface.