JPS6370305A - Correcting device for robot coordinate system - Google Patents

Abstract

PURPOSE:To calculate a coordinate correcting vector in a correcting vector calculating part and to correct respective working points by calculating diagonal calculation point coordinates based on reference points in a reference point recording part by a working coordinate calculating part. CONSTITUTION:Plural reference points for determining a working coordinate system are stored in the reference point storing part 1 in a correcting device and the coordinates of a working point in the working coordinate system is calculated by the working coordinate calculating part based on the reference points. Correcting reference points are stored in a correcting reference point storing part 3 and the coordinates of the working point and the correcting reference points are inputted respectively from respective storing parts 1, 3 to a correcting vector calculating part 4. The correcting vector is calculated by the calculating part 4 and the calculated correcting vector is inputted to a correcting working coordinate calculating part 5 together with the coordinates of the working point and the correcting reference points. The calculating part 4 calculates the coordinates of a diagonal reference point D4' of a reference point about the coordinate axes X, Y and outputs a coordinate correcting vector DELTAP based on a reference point D4 in the storing part 3 and the calculated diagonal reference point D4' and the calculating part 4 corrects respective working points based on the vector DELTAP.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to a robot when arranging workpieces in a workpiece tray (hereinafter referred to as a pallet) and taking out workpieces from a pallet (hereinafter referred to as a palletizing operation). , relates to a robot coordinate system correction device for correcting a robot coordinate system.

[Prior Art] In the assembly work of machines, etc., as shown in Fig. 4, a robot (not shown) performs palletizing work in which a plurality of workpieces (6) are sequentially taken out from a pallet (7) on which the workpieces (6) are arranged. accompany. In this case, if you try to have a so-called teaching play barfugu robot, which does not have the function of calculating coordinates, perform palletizing work, the workpiece (6 ) and the pallet (
When 7) has many lattice points, it is used for practical use≠)
Therefore, recently, robots with coordinate calculation functions are used to
This robot has three points (DI) at the distance of pallet (7), (
It has become common to teach only the coordinates of Dl) and (D3) and have all other grid points (DX) calculated by coordinate calculation. That is, by teaching the coordinates of the three corner points (Di), (Dl), and (D3) of the pallet (7),
The plane of the palette (7) is uniquely defined, and the coordinates of all other grid points (DX) can be calculated.

FIG. 5 is a block diagram of a robot coordinate system correction device that calculates the coordinates of other grid points by teaching the coordinates of three points. In Fig. 5, (1) is the reference point (Dl), (Dl) and (D3) that determines the working coordinate system of the plane of the pallet (7).
(2) is a reference point storage unit that stores (
This is a work coordinate calculation unit that calculates the position of a work point (DX) having a predetermined coordinate value as a combination of vectors based on the reference points (Dl) to (D3) stored in 1).

Next, FIG. 6 shows the relationship and deviation amount between the reference points (Di), (Dl), and (D3) by the conventional robot coordinate system correction device and the diagonal calculation point calculated by the work coordinate calculation unit (2). This is an explanation showing the occurrence of. In addition, in FIG. 6, reference points (Dl), (Dl), and (D3) are reference points (Dl).
is the origin of the work coordinate system, and the reference points (Dl) and (D3) are points that determine the vertical coordinate axis Y and the horizontal coordinate axis X, respectively. As mentioned above, a work point with a certain coordinate value (
04) is calculated by the work coordinate calculation unit (2) by combining vectors.

By the way, when positioning a robot with a multi-joint mechanism at the calculated work point (D4) calculated by the work coordinate calculation unit (2), the robot is positioned at a working point (D4°) that does not necessarily coincide with the calculated working point (D4). That is, the reference points (Dl), (Dl) and (
D3) is the calculated diagonal calculation point of the rectangle determined by (
When attempting to position the robot at the work point (i)4)), the robot ends up being positioned at a work point (D4°) that is separated by the amount of deviation Δ.

Note that the largest error will appear at the most diagonal point from the reference point (calculated reference point) indicated by the number of coincidences.

[Problems to be Solved by the Invention] As mentioned above, the conventional robot coordinate system correction device has the following problems:
The work coordinate calculation unit (2) calculates the work point (D4) on the work coordinate system.
Even if an attempt is made to calculate the calculated work point (D4) using a robot to position the robot, there is a problem in that accurate positioning cannot be performed due to accuracy errors of the robot itself.

The present invention has been made to solve the above problems,
Suppressing the influence of accuracy errors etc. of the robot itself,
An object of the present invention is to provide a robot coordinate system correction device that can position a robot at a calculated work point in a work coordinate system with high precision.

[Means for Solving the Problems] Therefore, the present invention includes a reference point storage section that stores a plurality of reference points for determining a work coordinate system, and a method based on the reference points.
a work coordinate calculation unit that calculates PJjM of a work point in a work coordinate system; a correction reference point storage unit that stores at least one correction reference point; and a correction reference point and work coordinates corresponding to the correction reference point. a correction vector calculation unit that calculates a correction vector based on the FE gauge calculated by the calculation unit;
A correction device for the robot coordinate system is composed of a correction work coordinate calculation section that corrects the work point based on the correction vector.

[Operation] In the robot coordinate system correction device configured as described above, the work coordinate calculation section calculates the coordinates of the diagonal calculation point based on the reference point stored in the reference point storage section, and the correction vector calculation section calculates the coordinates of the diagonal calculation point. A coordinate correction vector between the correction reference point stored in the correction reference point storage unit and the diagonal reference point actually indicated in number is calculated, and the correction work coordinate calculation unit calculates each work point based on the correction vector. Correct.

[Example 1] Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of a robot coordinate system correction device according to the present invention. In Fig. 1, (1) is a reference point storage unit that stores reference points (DI), (Dl), and (D3) that determine the working coordinate system of a plane, and (3) is a reference point storage unit that stores reference points for correction. (4) is a correction vector calculation unit; and (5) is a correction work coordinate calculation unit.

Next, the operation of the robot coordinate system correction apparatus according to the present invention will be described with reference to FIG. 2, which shows generation of a correction vector and correction of work point coordinates using the correction vector. In addition, in Fig. 2, the reference point (Dl), (D
1) and (D3), the reference point (Dl) is the origin of the work coordinate system, and the reference points (Dl) and (D3) are points that determine the vertical coordinate axis Y and the horizontal coordinate @X, respectively.

First, the correction vector calculation unit (4) calculates the two coordinate axes X and Y.
The coordinates of the diagonal reference point (D4') of reference point 1 are stored in the reference point storage unit (1) as reference points (Dl) to (D
Calculate by combining vectors based on 3).

Next, the actual number of the correction vector calculation unit (4) is shown,
The reference point (D) stored in the correction reference point storage unit (3)
4) and the calculated diagonal reference point (D4°), that is, the coordinate correction vector ΔP is calculated.

Next, the correction work coordinate calculation unit (5) calculates the correction vector ΔP
Based on this, each calculation point (lattice point) of the work coordinate system is corrected. The method of correcting each calculation point of the work coordinate system performed by the correction work coordinate calculation unit (5) is a proportional allocation method. That is, the coordinate vectors of the reference points (DI), (Dl), and (D3) are Pl
, Pl and P3, the reference point (DI
) and (Dl), let U and V be the ratio coefficients,
Coordinate vector P of the desired point.

is Px "PH+ (Pl - PI) u+ (P3-
P+ ) V +ΔP−u・V (1). Here, ΔP is a correction vector, and is ΔP-(P4 Pl)-((p2-p,")"CPs Pl)) (2). As mentioned above, the first formula has a correction term (△Pu-V) that is not found in the conventional calculation formula, and the correction work coordinate calculation section (5) is set at the diagonal reference point (D4°). Of course, correction calculations are also performed for other coordinate points.

In this way, it is possible to anticipate the occurrence of errors when positioning a robot, etc., and calculate a work point with the errors corrected in advance. When this is applied to an actual pallet (7), it becomes as shown in Fig. 3. That is, the robot can be positioned at the reference point (D4) and each work point (DI) without deviation from the reference points (Di), (Dl), and (D3).

In this embodiment, the correction calculation using the correction vector was performed using the proportional allocation method, but the correction calculation may be performed using other methods.

Further, although the work coordinate system is a plane in this embodiment, it may be a three-dimensional work coordinate system, and in this case, both the reference point and the correction reference point are extended to three-dimensional coordinates.

[Effects of the Invention] As explained above, according to the present invention, the work coordinate calculation unit calculates the reference point marked in the reference point La section (g).
Calculates the coordinates of the diagonal calculation point, and the correction vector calculation unit calculates a coordinate correction vector between the correction reference point stored in the correction reference point storage unit and the diagonal reference point actually indicated in number, The correction work coordinate calculation unit corrects the work point based on the correction vector, so even when positioning a work point in the work coordinate system with a device such as a robot, the influence of errors caused by the robot itself can be suppressed to some extent. This has the effect of allowing highly accurate positioning.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a robot coordinate system correction device according to the present invention, FIG. 2 is an explanatory diagram of correction of the coordinate system using a correction vector by the robot coordinate system correction device shown in FIG. 1, and FIG. The figure is an explanatory diagram when applying coordinate system correction to a pallet, Figure 4 is an explanatory diagram of a pallet, Figure 5 is a configuration diagram of a conventional robot coordinate system correction device, and Figure 6 is a diagram of a conventional robot coordinate system. FIG. 3 is an explanatory diagram of generation of positional deviation amount of diagonal calculation points by the correction device of FIG. In each figure, reference numeral 1 indicates a unit for writing reference points, 3 indicates a reference point storage unit for correction, 4 indicates a correction hector calculation unit, and 5 indicates a correction work coordinate calculation unit. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Patent Attorney Tadashi Sato Figure 3

Claims (2)

[Claims] (1) A reference point storage unit that stores a plurality of reference points for determining a work coordinate system, and a work coordinate calculation unit that calculates the coordinates of a work point within the work coordinate system based on the reference points. In the robot coordinate system correction device, the correction reference point storage section stores at least one correction reference point, and the correction reference point and the work coordinate calculation section corresponding to the correction reference point calculate the coordinate system. A robot coordinate system comprising: a correction vector calculation section that calculates a correction vector based on the coordinate point; and a correction work coordinate calculation section that corrects the work point based on the correction vector. correction device. (2) The work coordinate system is a plane palette determined by four reference number indicating points, and one of the reference teaching points includes a diagonal point as a reference point for correction. The robot coordinate system correction device according to item 1.