JPH11226886A - Correcting method for robot track - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a correcting method which can easily correct a robot track formed in an off line in a short time. SOLUTION: Based on a robot data, robot operating range, and a tool attitude in the case of performing paint work by a robot, a singular point locus S1 , S2 in the robot is obtained, and the shortest distance hmin between this singular point locus S1 , S2 and a robot track PcPi obtained in accordance with a workpiece is obtained. After evaluating accuracy of the robot track by whether this shortest distance hmin is in a permissible value rs or not, an original position of the robot is deviated so that the shortest distance hmin exceeds the permissible value rs .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of correcting a robot trajectory for avoiding an operation near a singular point.

[0002]

2. Description of the Related Art In recent years, robots have been widely put to practical use in the production process of various mass-produced products, and robots have also been put to practical use in large structures such as ships and bridges.

For example, most welding operations are performed by welding robots. However, even in painting operations in which economic effects are not sufficiently exhibited as compared with welding, there is still a problem of securing skilled workers and the like. Robotization is desired.

[0004] In general, painting robots are widely used in the automobile industry and their operation data (NC data).
Was obtained by manual teaching. By the way, teaching by hand to the robot can be performed relatively easily when the painting range is small and the movement of the robot is not complicated, such as in a car, but in the case of a large structure, Since the painting area is large and many stiffening members protrude from the painting surface, there is a problem that manual teaching requires time and effort.

For this reason, it is necessary to create operation data of the robot by programming offline.
When creating robot operation data offline, the robot reads the structure data, coating condition data, and painting method data of the object to be coated from the library, and generates robot operation data, that is, a robot trajectory based on these data. I was

With respect to the robot trajectory generated off-line, accuracy check for stable painting work or exercise of necessary work skills is performed using, for example, a Jacobian determinant, and correction work is also performed. Have been done.

Conventionally, this correction work has been performed by trial and error.

[0008]

When a correction operation is performed by trial and error, it is necessary to appropriately change the origin position of the robot, regenerate the robot trajectory, and check the accuracy again using the Jacobian matrix. However, there is a problem that a lot of labor and time are required.

Accordingly, an object of the present invention is to provide a correction method that can easily and quickly correct a robot trajectory generated off-line.

[0010]

In order to solve the above-mentioned problems, a first method of correcting a robot trajectory according to the present invention is to provide a robot specification, a robot operation range and / or a tool when a predetermined operation is performed by a robot. Based on the posture, the singular point of the robot is determined, and the singular point is defined as the singular area within the range with the permissible value as the center of this singular point. After evaluating whether or not the robot passes through the area, the original position of the robot is shifted so that an arbitrary point on the robot trajectory does not pass through the singular area.

A second method of correcting a robot trajectory according to the present invention obtains a singular point trajectory of a robot based on a robot specification, a robot operation range, and / or a tool posture when a predetermined operation is performed by the robot. After obtaining the shortest distance between the singular point trajectory and the robot trajectory obtained according to the work target, and evaluating the accuracy of the robot trajectory by determining whether or not this shortest distance is within an allowable value, the shortest distance is calculated as follows. This is a method of shifting the robot origin position so as to exceed the allowable value.

According to each of the above-mentioned correction methods, a singular region including a singular point of the robot at the time of performing the work is obtained, and the trajectory accuracy is evaluated based on whether or not the robot trajectory passes through this singular region. In order to evaluate the trajectory accuracy by calculating the shortest distance between the singular point trajectory of the robot and the robot trajectory when performing the work and comparing the shortest distance with the allowable value, the Jacobi matrix is used. It does not require complicated and enormous calculations as in the case.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for correcting a robot trajectory in a work according to an embodiment of the present invention will be described below with reference to FIGS.

In the present embodiment, a method of correcting a trajectory in a multi-joint type painting robot will be described.
By the way, the method of correcting the robot trajectory is based on the accuracy evaluation method of the robot trajectory described below, and the accuracy evaluation method will be described first.

The object to be painted (an example of an object to be worked, hereinafter simply referred to as a work) in the present embodiment is a hull block, which is assembled by horizontal and vertical members, and has a box shape. Have been.

For example, as shown in FIG. 1, this hull block 1 has a beam member 3 attached to the inner surface of a hull outer plate 2 as a stiffening member, and a partition wall member perpendicular to the hull outer plate 2. A case where the surface of the hull block 1 is automatically painted by a painting robot (hereinafter, referred to as a robot) will be described.

First, an orbit, that is, operation data of a robot having a painting gun (hereinafter, referred to as a tool) attached to a wrist is obtained by an operation data generation system (computer system).

That is, as shown in the flowchart of FIG. 2, in the trajectory generation system, the work structure data is read from the CAD data 11 and recognized, and the painting condition data from the painting library 12 and the painting work from the work library 13 are read. Based on these data, the robot trajectory, that is, the moving speed of the tool, the tool posture, the tool tip trajectory, etc. are obtained. After a predetermined check (described later) is performed, the NC data is offline. Is generated.

More specifically, the information given to the data generation system when generating the trajectory is the structural data of the work at the reference coordinates where the robot is installed and the specifications of the robot. That is, when the work structure is numerically recognized based on the information from the CAD, the origin position of the robot is determined based on the operation range which is one of the specifications of the robot, and the recognized work structure and the determined robot are determined. A painting path and a movement path corresponding to each part of the work are generated as a robot trajectory according to the origin position and the tool posture.

Next, a check is made as to whether the generated robot trajectory is appropriate, that is, an interference check and a trajectory accuracy check (evaluation) are performed. Hereinafter, a method for evaluating the accuracy of the trajectory will be described. The interference check is naturally performed, and the check is easy.

The trajectory accuracy is evaluated based on whether or not the robot trajectory passes through the region of the singular posture in which the motion performance deteriorates. First, the robot posture in the generated trajectory is determined. The trajectory of the singular point, that is, the singular posture, is obtained by calculation.

The special posture includes a wrist and a shoulder. Fig. 3
As shown in (a), when the wrist part 32 and the forearm part 33 of the robot 31 fixedly holding the tool 21 are in a straight line, that is, when the tool posture is constant (hereinafter referred to as a wrist singular posture), the shoulder part 3B, the rotation center point 34 of the wrist 32 of the robot 31 is
Is located on the turning center axis 36 of the first joint axis 35 of the robot 31 (hereinafter, referred to as a shoulder specific posture).

Here, actually, the robot is operated,
FIG. 4 shows a case where the robot is given a trajectory passing through the singular point and its vicinity, and errors in the tool tip (TCP) and the tool posture at every moment are observed at a horizontal angle of 15 degrees and a depression angle of 30 degrees. The specified speed is
The speed required for heavy coating with a large film thickness is 300 mm /
s. From FIG. 4, in the trajectory passing near the singular point, especially as the wrist singular point _Sh is approached,
It can be seen that there is an error in the trajectory accuracy of the tool tip, tool posture, etc.

The relationship between the distance from the singular point and the trajectory accuracy was ascertained by taking the amount of shift of the trajectory in the Y and Z directions from the trajectory including the singular point as a measurement parameter. The wrist singularity is shifted in the Y and Z directions, and the shoulder singularity is shifted in the Y direction.

FIG. 5 shows a measurement result of each trajectory error with respect to a shift amount from the singular point trajectory, that is, a spatial distance from the singular point. FIG. 5A shows a tool tip (TCP),
(B) represents the tool posture, and (c) represents the moving speed. From FIG. 5, it can be seen that the singular point orbit is shifted in the Y and Z directions from the singular point trajectory, and the shoulder singular point is shifted in the Y direction.
That is, for any accuracy item, it can be read that the error is inversely proportional to the distance from the singular point.

By the way, the path error ΔP at the tip of the tool and the tool attitude error Δψ are synergistic to become the target position error δ on the coating surface. The maximum value that the target position error δ of the coating surface can take is that the coating distance between the coating gun, which is a tool, and the coating surface is L.
Then, it is represented by the following equation (1).

Δ ≒ ΔP _max + L × Δψ (1) From the measurement result of the trajectory error shown in FIG. 5 and equation (1), the spatial distance from the singular point to the trajectory and the maximum value of the target position error of the coating surface. 6 is as shown in FIG. 6 if L = 300 mm. FIG. 6 shows that the error is again inversely proportional to the distance from the singular point.

As described above, since the trajectory accuracy depends on the distance from the singular point, in order to maintain the trajectory accuracy, an area having a radius around an allowable value centered on the singular point is provided. It can be seen that the trajectory accuracy should be evaluated based on whether or not the robot trajectory to be evaluated passes through this singular region.

For example, assuming that the allowable value of the target position error on the coating surface is 30 mm, it is understood that the trajectory needs to be separated from the singular point by 10 mm or more as shown in FIG. As described above, the area in which the trajectory accuracy is degraded is regarded as a singular area, and whether the robot trajectory passes through this singular area can be evaluated very easily.

As shown in FIG. 7, if singular point trajectory 41 Sadamare as a set of singular points, the allowable value r _s from the singular point along the specific point trajectory 41 with a radius and a set of the radius r _s Is obtained.

Therefore, as a method of trajectory evaluation, if the shortest distance in space between the robot trajectory (line segment) and the singular point trajectory (line segment) is larger than the radius of the singular point region, the trajectory is determined. If it is acceptable, it can be determined that it is not possible if it is small.

By the way, the value of the radius of this singularity area is
It is preferable to determine based on the actual work, and specifically, a value proportional to the moving speed specified in the painting work. [A] Here, an evaluation method in the case of a wrist among the above singular points will be described in detail.

First, a method of obtaining the trajectory of the singular point of the wrist will be described. Generally, in order to obtain a paint trajectory, that is, a robot trajectory, a target point (target position of a tool which is a tool tip), a tool posture, and a linear velocity are designated. FIG. 8 illustrates a trajectory that draws a wrist singular point of a puma-type robot when a fixed tool posture is designated. It is assumed that the tool axis and the wrist axis are arranged on the same axis.

As shown in FIG. 8, the trajectory of the wrist singular point corresponds to the vector * a [symbol *
Indicates that the character described thereafter is a vector (hereinafter the same), and in the following equation, the vector is shown in bold.] And the second joint axis (θ ₂ ) is movable while being kept parallel to This is a locus drawn by the tool tip (TCP) when moved within the range, and is an arc S ₁ S ₂ having a radius equal to the length of the upper arm. This arc lies on a plane π determined by the vector * a.

Hereinafter, a wrist singular point locus will be obtained. (1) First, Z- is given as a part of NC data.
A tool axis (wrist axis) direction vector * a = [x _a , ya _a , z _a ] ^T viewed from the reference coordinate system is obtained from the tool posture based on the YX Euler angles (α, β, γ).

The vector * a is obtained by the following equation (3) from a rotation transformation matrix [shown in the following equation (2)] up to the tool based on the joint angle of the robot.

[0037]

(Equation 1)

(2) Next, when the joint angle θ ₁ (* a) of the first axis with respect to the plane π including the tool axis direction * a is obtained,
The following equation (4) is obtained. _{tanθ 1 (* a) = y} a / x a ··· (4) (3) Next, determine the singular point trajectory.

The singular point locus is, as shown in FIG. 8, an arc having a radius equal to the length L _{1 of the} upper arm, and the center c of the locus is shown in FIG.
In the robot coordinate system (x ₀ −y ₀ −z ₀ ) shown in (5), it is expressed by the following equation (5), and on the plane π, the following (6)
It is represented by the formula.

[0040]

(Equation 2)

The circle c is represented by the following equation (7) on a plane π by the parameter φ shown in FIG.
In the robot coordinate system, it is expressed by the following equation (8).

[0042]

(Equation 3)

(4) Next, the range of the singular point locus is determined. The range S ₁ S ₂ of the singular point set taking an arc is the range of each joint angle of the upper arm and the forearm and the specified tool axis direction vector *
a. Hereinafter, it is considered on the plane π.

The joint angle range between the upper arm and the forearm is set as follows in the direction shown in FIG. The range of motion of the forearm is for the upper arm. Brachial operating _{range: θ 2min ≦ θ 2 ≦ θ} 2max forearm operating _{range: θ 3min ≦ θ 3 ≦ θ} 3max S 1 is the upper arm articulation point q _2Cr1 satisfying the following equation (9) (*
Depending on the argument of a), the cases are classified as shown in the following equation (11). In addition, S ₂ satisfies the following equation (10): q
_{According to the declination of 2cr2} (* a), the cases are classified as shown in the following equation (12). Note that (9) The solution of equation and equation (10), to select the solution of _{z Q2 / x Q2> z a} / x a.

[0045]

(Equation 4)

The argument of the vector in complex number notation is represented by arg, and the value of the corresponding parameter φ is determined by equation (11) for S _{1 and} by equation (12) for S ₂ .

[0047]

(Equation 5)

Once the trajectory of the wrist singular point is determined, it is necessary to determine the shortest distance between the trajectory of the wrist singular point and the robot trajectory. Hereinafter, a method of obtaining the shortest distance will be described.

Incidentally, the trajectory of the wrist singular point is an arc on an arbitrary vertical plane, and the robot trajectory is an arbitrary line segment in space, and it is difficult to directly determine the shortest distance between them.

Therefore, the algorithm for calculating the shortest distance between the trajectory of the wrist singularity and the robot trajectory will be described in consideration of the practicality of incorporating it into the system for generating the coating data of the structure.
Calculate under the following conditions.

As the first condition, since most of the work is a box-shaped structure, the directions of the coating trajectory are all horizontal and vertical directions parallel to the robot reference coordinates. As a second condition, in consideration of the adhesion of the paint on the application surface, the attitude angle of the paint gun, which is a tool, with respect to the application surface is desirably 90 degrees. ) And the tool are up to 45 degrees.

In the following, the shortest distances in the horizontal painting and the vertical painting will be obtained in consideration of these conditions. Here, the tool tip trajectory P _c P _t is represented by the parameter t
Is expressed by the following equation (13).

[0053]

(Equation 6)

(A) Find the shortest distance in horizontal painting. First, a point closest to the shortest distance is obtained on the robot trajectory or the wrist singular point trajectory, and then the shortest distance is searched for at a constant interval by using this point as a starting point. by this,
The algorithm required for the driving data generation system is minimized by minimizing the time required for the search.

By the way, in this method, a point on the robot trajectory is searched to find the shortest distance from the trajectory of the wrist singularity, and a point on the trajectory of the wrist singularity is searched to determine the shortest distance from the robot trajectory. There is a way to find it.

The former can be reduced to the problem of finding the shortest distance between a point and a circle in a space, and a search formula can be found geometrically in space. The latter can also be reduced to the problem of finding the shortest distance between a point and a straight line in space, and a search expression can be found using algebraic geometry.

In the present embodiment, referring to FIG. 10, the shortest distance between the search point on the robot trajectory and the arc-shaped wrist singular point trajectory is spatially geometrically obtained by the following procedure. (1) First, a projection point P _i π of the search point P _i (predetermined point) onto the plane π is obtained. (2) Next, determine the intersection S _ci between the line segment and the arc S ₁ S ₂ connecting the arc center C and P _i [pi wrist singularity locus (S ₁ S _2). (3) Then, the shortest distance h (P _i) with respect to P _i = P _i S
_ci is given by the following (1)
It is obtained by the equation 4).

(P _i S _ci ) ² = (P _i πS _ci ) ² + (P _i P _i π) ² (14) If there is no intersection S _ci , the end point S _{1 of} the arc is taken as of S _2, and select a point near the intersection, directly determines the length of the line segment.

It is inefficient to perform the search in order from the end of the trajectory. Therefore, according to the prerequisites of the algorithm, a near point which is almost the shortest distance is selected as the search starting point, and the search is performed on the left and right sides. , With the minimum number of search points.

[0060] That is, as the search starting point P _0, it is to choose the intersection Pπ the plane π containing the robot path P _c P _t and wrist singular point trajectory. If the intersection is not present among the orbital end point P _c and P _t, selecting a point closer to Ppai.
These are based on the condition that an extreme tool posture is not taken.

The comparison between the previous search point and the shortest distance is as follows.
Do it. h (P_i)> H (P_i-1): Shortest distance h = h (P_i-1) H (P_i) ≦ h (P_i-1): Continue search (i = i + 1) where P₀If is inside the orbit, it is shown in FIG.
So the starting point P₀Divided into right and left
, And finally, find their minimum value by the shortest distance h _minWhen
I do. Search point P here_iIs the starting point P₀Showing trajectory from
It is moved outward according to the equation (13).

When P ₀ is P _c or P _t , the search may be performed in one direction. Note that the interval between the search points is equal to the radius r used to define the singular region, as shown in the following equation (15).
_It is good to set to about 1/2 of _s .

[0063]

(Equation 7)

(B) Next, the shortest distance in vertical painting is determined. Under the condition that the painting trajectory is almost parallel to the robot reference coordinates, in vertical painting, the robot trajectory and the plane π including the wrist singularity trajectory are almost parallel, and thus the robot trajectory and the wrist singularity trajectory Can be obtained without using a search method.

Hereinafter, the procedure to be determined will be described with reference to FIG. (1) First, the projection line P _c πP _t π onto the plane [pi robot trajectory P _c P _t. Note that the projected trajectory on the plane π *
pπ is the rotation transformation matrix ( ¹ R ₀ · *) of the robot trajectory * p
In p), the y component is set to zero. (2) Next, the projected line segment P _c πP _t from the point C on the plane π
The intersection S ₀ of the perpendicular CH ₀ down to π and the arc S ₁ S ₂ is determined. (3) Next, a point P ₀ on the robot trajectory corresponding to H ₀ (having the same vertical axis coordinates) is obtained. (4) Therefore, basically, the wrist singularity locus S ₁ S ₂
The shortest distance between the robot path P _c P _t is expressed by the following equation (16).

(S ₀ P ₀ ) ² = (S ₀ H ₀ ) ² + (H ₀ P ₀ ) ² (16) However, in detail, S and H represent the wrist singular point trajectory and the projected trajectory, respectively. Is determined according to the case shown in the following equation (17). In addition, the case where the point in the space is on the line segment is represented by ⊆, and the case where it is not present is represented by ⊃.

[0067]

(Equation 8)

The shortest distance between the robot trajectory in the horizontal painting operation and the robot trajectory in the vertical painting operation thus determined and the trajectory of the wrist singular point is determined, and the shortest distance is compared with an allowable value. Then, the accuracy of the trajectory is evaluated. [B] Further, a description will be given of an evaluation method in the case of a shoulder among the above-mentioned singularities.

First, a method of obtaining the locus of the shoulder singular point will be described. In general, to obtain a paint trajectory, that is, a robot trajectory, a target point (target position of a tool as a tool tip), a tool posture, and a linear velocity are designated. as shown in b), regardless of the tool position, the robot wrist rotation center (hereinafter, referred to as wrist center) is position that is on the axis of the theta ₁ axis that is the first joint. In other words, the shoulder singularity locus, a locus through which the wrist unit around a segment of the theta _1-axis, as shown in FIG. 13.

[0070] Therefore, even robot trajectory in order to evaluate, in the tool tip (TCP) rather than the orbit of the wrist portion center Q _3. That is, the z coordinate of the singular point locus is given by the following (1) by θ ₂ and θ ₃ satisfying the following equation (18).
It is expressed by the equation 9).

[0071]

(Equation 9)

That is, the line segment S₁S_TwoThe upper and lower limits are θ_Twoaxis
And θ_ThreeDepending on the joint angle range of the shaft and the ratio of the upper arm and forearm lengths.
And in general, S₁Is θ_Two(S₁) = Θ_2minOr
θ_Three(S _Two) = Θ_3minIs determined by

Once the trajectory of the shoulder singularity is obtained, it is necessary to obtain the shortest distance between the trajectory of the shoulder singularity and the center trajectory of the wrist which is the robot trajectory. Hereinafter, a method of obtaining the shortest distance will be described.

The wrist center trajectory Q _c Q _t (* q) corresponding to the trajectory of the tool tip (TCP) is represented by the following equation (20).

[0075]

(Equation 10)

(A) First, the shortest distance in horizontal painting (horizontal work) is determined based on FIG. (1) trajectory Q _c Q _t is in the horizontal plane from the above track conditions, the horizontal plane [pi, for example, be determined by averaging the z-coordinate values of Q _c Q _t.

(2) An intersection Sπ between a straight line including the shoulder singularity locus S ₁ S ₂ and the plane π is obtained. Of course, the z-coordinate value of Sπ is a value in plane π. (3) from Espai, a vertical line (EsupaiH) the straight line including a trajectory Q _c Q _t on the plane [pi, and the intersection H.

[0078] (4) a shoulder singularity shortest distance between the locus S ₁ S ₂ and the track Q _c Q _t is Sπ and H are different whether each lies on the shoulders singular point trajectory and the trajectory, each intersection Sπ and H
When they are on the trajectory and the trajectory, respectively, the distance between SπH is the shortest distance.

The shortest distance in each case is shown in the following equation (21).

[0080]

[Equation 11]

(B) Next, the shortest distance in vertical painting (vertical work) is determined based on FIG. In the vertical painting, as shown in FIG. 15, the trajectory is almost parallel to the shoulder singularity locus, and in this case, the shoulder singularity locus S
Whether orbits Q _c Q _t have perpendiculars to ₁ S ₂
The case is divided as in the following equation (22).

[0082]

(Equation 12)

The shortest distances of the wrist center trajectory in the horizontal painting, the wrist center trajectory in the vertical painting, and the shoulder singular point trajectory thus obtained are determined, and these shortest distances are allowed. The accuracy of the trajectory is evaluated by comparison with the values.

If the shortest distance obtained is smaller than the allowable value, the wrist center trajectory (robot trajectory)
Is moved, and the above-described evaluation is performed again. Of course,
Continue until the shortest distance is greater than the allowed value.

Next, a description will be given of a method of correcting the trajectory of the robot when the robot trajectory passes through the singular region using the above-described accuracy evaluation method. This fix is
The determination is performed based on the shortest distance between each singular point locus and the robot trajectory obtained at the wrist or the shoulder.

That is, when finding the shortest distance between the robot trajectory and the singular point trajectory, the coordinates of each point on the trajectory and the trajectory are known, so that the distance between the two points is, of course, since you can see about, as shown in FIG. 16, the shortest distance h _min with a specific point trajectory S ₁ S ₂ and the robot trajectory P _c P _t exceeds the allowable value r _s (r _s + α) manner, and for example, the robot The singular point trajectory itself is shifted in a direction perpendicular to the trajectory (shown by a broken line).

As described above, by using the shortest distance between the robot trajectory and the singular point trajectory obtained in a short time and easily, the corrected data can be obtained without using the Jacobi matrix. The robot trajectory can be corrected in a short time and easily.

[0088]

As described above, according to the method of correcting each robot trajectory according to the present invention, by using the shortest distance between the robot trajectory and the singular point trajectory, the corrected data can be obtained without using the Jacobian matrix. Therefore, the robot trajectory can be corrected in a short time and easily.

[Brief description of the drawings]

FIG. 1 is a bird's-eye view of a main part of an object to be painted in an embodiment of the present invention.

FIG. 2 is a flowchart showing a schematic procedure for generating a robot trajectory according to the embodiment;

FIG. 3 is a schematic diagram showing a unique posture of the robot according to the embodiment.

FIG. 4 is a diagram showing errors in the tool tip and tool posture when the robot passes near a singular point of the robot in the embodiment.

FIG. 5 is a graph showing a measurement result of a trajectory error in the robot according to the embodiment.

FIG. 6 is a graph showing a measurement result of a target position error on a coating surface in the robot according to the embodiment.

FIG. 7 is a graph showing a relationship between a robot trajectory and a unique region of the robot in the embodiment.

FIG. 8 is a graph showing a relationship between a robot posture and its unique region in the embodiment.

FIG. 9 is a schematic diagram showing a range of a trajectory of a singular point of a wrist of the robot in the embodiment.

FIG. 10 is a perspective view illustrating a procedure for obtaining the shortest distance between the robot trajectory and the wrist singularity trajectory in the horizontal operation according to the embodiment.

FIG. 11 is a perspective view illustrating a procedure for obtaining the shortest distance between the robot trajectory and the wrist singularity trajectory in the horizontal operation in the embodiment.

FIG. 12 is a perspective view for explaining a procedure for obtaining a shortest distance between a robot trajectory and a wrist singularity trajectory in a vertical operation in the embodiment.

FIG. 13 is a schematic diagram illustrating a shoulder specific posture in the robot according to the embodiment.

FIG. 14 is a perspective view illustrating a procedure for obtaining the shortest distance between the robot trajectory and the shoulder singular point trajectory in the horizontal painting in the embodiment.

FIG. 15 is a perspective view illustrating a procedure for obtaining the shortest distance between the robot trajectory and the shoulder singularity trajectory in the vertical painting in the embodiment.

FIG. 16 is a perspective view illustrating a method of correcting the robot trajectory according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hull block 2 Hull outer plate 3 Beam material 4 Partition material 21 Tool 31 Robot 32 Wrist part 33 Forearm part 34 Center of rotation 35 First joint axis 36 Center axis of rotation 41 Singular point locus 42 Singular area _{Pc Pt} robot trajectory S ₁ S ₂ singular point locus h _min shortest distance r _s tolerance

Claims (2)

[Claims] 1. A singular point in a robot is determined based on a robot specification, a robot operating range, and / or a tool posture when a predetermined operation is performed by the robot, and an allowable value is defined as a radius around the singular point. After defining the inside of the range as a singular region and evaluating the accuracy of the robot trajectory determined according to the work target by whether or not the robot passes through the singular region, any point on the robot trajectory is within the singular region. A method of correcting a robot trajectory, wherein the origin position of the robot is shifted so as not to pass through the robot. 2. A singular point trajectory of the robot is determined based on robot specifications, a robot operation range, and / or a tool posture when a predetermined operation is performed by the robot, and the singular point trajectory and the work object are determined. Find the shortest distance from the robot trajectory obtained, evaluate the accuracy of the robot trajectory by checking whether this shortest distance is within the allowable value, and then shift the robot origin position so that the shortest distance exceeds the allowable value. A method for correcting a robot trajectory, characterized in that: