JP3511551B2 - Robot arm state detection method and detection system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the relative position between a rotation axis and the coordinates of an image when positioning is performed by image processing in automatic assembly work using a robot arm, and further, the tilt angle of the axis, etc. The present invention relates to a robot arm state detection method and a detection system for improving the accuracy of work by detecting and correcting the mechanical error factor.

[0002]

2. Description of the Related Art Currently, in positioning control of machine tools and robots, instead of operation control based on visual confirmation by humans,
Recognition by image processing is often used. As a method using this image processing, a method of applying markings to a detection target or an external workbench and detecting them, a method of identifying and detecting a characteristic point of the detection target, and the like are applied.

As a reference technical document relating to such a technique, for example, in "Robot Arm Relative Attitude Correction Method" of Japanese Patent Application Laid-Open No. 4-313106, a robot arm axis having a working tool fixed to its tip is described. The configuration is such that the image pickup direction is aligned with the axial direction, and a television camera is fixed to the tip of the axis of another axis that is vertically attached from the axis. There is disclosed a technique of predicting the position of a work object from the position of each mark by rotating the mark and forming the relative posture of the working tool.

Further, in the "Visual Information Processing Device for Space" of Japanese Utility Model Laid-Open No. 5-2894, a camera is mounted on an end effector of a robot to detect an image pickup pattern of a mark described on a member to be assembled, A technique is disclosed in which the drive path of the arm is determined by measuring the distance and direction of the arm tip from the assembly target member by measuring the area of the pattern and the center of gravity.

[0005]

In the conventional technique as described above, it is necessary to clarify the relative position between the work tool (end effector) and the imaging device and the posture of the work tool or the robot arm. is there. However, due to the positioning accuracy between the frame and the image sensor in the image pickup device, design tolerances (such as stacking of component tolerances), robot design tolerances, and assembly errors, the image pickup device and the robot arm can be accurately measured using only the design values and actual measurement values. Since the relative position with respect to the axis cannot be known, there is a problem in that the positioning for work by image recognition becomes inaccurate.

The present invention has been made in view of the above, and determines the relative position and relative attitude between the image pickup device and the axis of the robot arm, and the reference plane in the image plane,
The purpose is to achieve work positioning with high accuracy by detecting the state of the robot by image recognition and clarifying the error factors.

[0007]

[0008]

[0009]

[Means for Solving the Problems]
Therefore, in the robot arm state detection method according to claim 1 , a robot arm state detection method for performing position detection / positioning of a detection target from an image picked up by an image pickup means attached to a tip of the robot arm. In the above, the imaging direction of the imaging means is fixed to the vertical tip on the rotation axis of the robot arm so as to match with the horizontal reference plane on which the directional marking is applied, and the marking is known by the imaging means. The first step of obtaining the coordinates of the characteristic points of the imaged marking, the second step of obtaining the direction of the marking image obtained by the first step, the first step, and A third step of rotating the robot arm around the axis of the robot arm at an appropriate angle based on the result of the second step, and before and after the rotation of the robot arm. It is intended to include a fourth step of detecting the coordinates of said extension taken image of the virtual center of rotation of the robot arm from the attitude and the optical magnification of the marking.

That is, by setting the optical magnification to a known value, the center of rotation is detected as the coordinates in the virtual image plane obtained by expanding the image plane, even if the axis of rotation does not exist in the image plane. It is possible to correct the relative position of the detection target based on the image with respect to the center of the shaft, with the center of rotation of the shaft as the reference for position detection / positioning of the detection target.

According to a second aspect of the present invention, there is provided a robot arm detection system, wherein the robot arm is attached to a tip end of the robot arm, and image pickup means for picking up directional markings provided on a horizontal reference plane, and the robot. The image pickup means can be attached to and detached from the arm, and the attachment means includes a mechanism for rotating around the axis of the robot arm, and the calculating means for calculating coordinates and angles from the image obtained by the image pickup means. Then, the computing means detects the center of the mounting means as coordinates in the image plane based on the method for detecting the state of the robot arm according to claim 1 , and uses the detected value to detect the robot arm and the robot arm. The offset correction with the mounting means is executed.

That is, even if the robot arm is not provided with a rotation mechanism, a rotation mechanism whose rotation center position is known is provided at the mounting portion of the axis of the robot arm.
With the detection method described above, the reference coordinates of the image can be obtained only by the mechanical error factors that can be measured from the outside, without considering the positioning error of the image pickup device of the image pickup means or the design intersection.

In the method for detecting the state of the robot arm according to a third aspect of the present invention, the state of the robot arm for detecting and positioning the object to be detected from the image picked up by the image pickup means attached to the tip of the robot arm. In the detection method, the first step of aligning the rotation center axis of the robot arm and the image pickup device of the image pickup means in a vertical line, and fixing the image pickup direction vertically to the robot arm with an arbitrary device in the line as an origin. A cylinder having a radius perpendicular to a horizontal reference plane and having a radius from the center of rotation of the robot arm to the image pickup distance of the image pickup means is set, and a reference line is set inside the cylinder parallel to the circumference. The intersection of the step 2 and the axis of rotation of the robot arm and a line extending perpendicularly from the origin of the image sensor to the axis of rotation of the robot arm is the center of the cylinder, A third step of teaching the robotic arm to a height of the reference line, the robot arm while providing the known angular rotation about the axis One,
The angle between the tangent line at the intersection of the fourth step of arbitrarily imaging the reference line and the perpendicular line passing through the origin in the image plane of the reference line imaged in the fourth step and the normal line of the image is 90. And a fifth step of detecting the tilt angle of the robot arm.

That is, when it is expected that the axis direction of the robot arm and the rotation axis coincide with each other, the rotation mechanism of the axis and the imaging means for imaging the direction perpendicular to the axis direction
The angle that becomes parallel to the horizontal row in the image plane is detected, and the tilting direction of the axis is detected.

Further, in the robot arm state detecting method according to a fourth aspect , the distance between the origin and the reference line in the tilt angle direction detected in the fifth step according to the third aspect is stored. , Detecting the distance between the origin in the image plane and the reference line, comparing the detected value with the stored value, and detecting the tilt angle of the robot arm Is.

[0016] That is, stores the distance between the origin and the reference line in the detected tilt angle direction in a fifth step according to claim 3, further when the 180 ° rotation of the robot arm around the axis By detecting the distance between the origin in the image plane and the reference line and comparing this with the stored value, it is possible to detect the tilt angle of the robot arm, ignoring the subtle changes in the imaging distance due to tilt. It will be possible.

Further, in the robot arm detection system according to the fifth aspect, a reference cylinder for tilt detection which is set / fixed vertically to a horizontal reference plane and an imaging direction is provided at the tip of the robot arm. An image pickup means fixed with its axial direction perpendicular to it, and a mechanism for rotating so that the rotation center axis of the robot arm and a vertical line of the image pickup means are parallel to each other and the axial direction and the image pickup direction are perpendicular to each other. Mounting means,
A calculating means for calculating an angle formed by a tangent line of a reference line and a perpendicular line passing through an origin in an image plane from an image obtained by the image pickup means, based on the robot arm state detecting method according to claim 3 or 4. And are provided.

That is, a system for detecting a tilt angle of a robot arm using the method for detecting a state of a robot arm according to the third or fourth aspect is realized.

Further, in the state detecting method of the robot arm according to the sixth aspect , the state of the robot arm for detecting and positioning the position of the detection target from the image picked up by the image pickup means attached to the tip of the robot arm. In the detection method, markings that are provided on each of the horizontal first reference surface and the second reference surface that has a known angle with respect to the first reference surface and that are directional and equidistant are used. A first step of imaging the marking on the first reference surface provided on the horizontal first reference surface by the imaging means, and a second step of imaging the marking on the second reference surface by the imaging means And a third step of obtaining the coordinates of the characteristic points of the two marking images obtained by the first step and the second step and further obtaining the marking direction, and the center of the robot arm And a fourth step of rotating the robot at an appropriate angle perpendicular to the axial direction, and a fifth step of detecting and correcting the tilt angle in the second reference plane direction from the marking postures of the robot arm before and after rotation. It includes a process and.

That is, when the tilt direction is known,
It is possible to detect the tilt angle of the robot arm in any direction and correct the mechanical tilt.

Further, in the robot arm detection system according to the seventh aspect, each surface has directionality,
And a horizontal first reference plane with markings at equidistant positions, and a second reference plane having a known angle with respect to the first reference plane
Attached to the reference surface and the tip of the robot arm, the first
Imaging means for imaging the reference plane and the second reference plane, and computing means for calculating coordinates and angles from the image obtained by the imaging means based on the method for detecting the state of the robot arm according to claim 6 . It is equipped with.

That is, a system for detecting the tilt angle of the robot arm using the method for detecting the state of the robot arm according to claim 6 is realized.

Further, in the state detecting method of the robot arm according to the eighth aspect , the position of the detection object is detected from the images picked up by the two image pickup means mounted on the tip of the robot arm and having different image pickup directions by 180 °. A method for detecting a state of a robot arm for performing detection / positioning, wherein an angle formed by a tangent line of a reference line detected by each of the two image pickup means and a perpendicular line passing through an image plane is determined by displacement of a rotation angle of the robot arm. When there is a phase shift of 180 °, the step of determining that the rotation axis of the robot arm and the robot arm match and deviates from the vertically downward direction, and the reference line and the perpendicular line of either one of the two image pickup means. If the intersection is at a higher position in the screen than the other and the perpendicular and the tangent to the reference line are vertical, the axis of rotation of the robot arm and the robot arm match. If it is not vertical in the above step and the step of determining that the rotation axis is vertically downward, it is determined that the rotation axis of the robot arm does not match the robot arm and the rotation axis does not match vertically downward. The process of
Is included.

That is, by the respective steps described in claim 8 , it is possible to judge whether or not the robot arm and the rotation axis thereof match, and whether or not the rotation axis and the vertically downward direction match.

Further, in the robot arm detection system according to the ninth aspect, a reference cylinder for tilt detection which is set / fixed vertically to a horizontal reference plane and an imaging direction at the tip of the robot arm are provided. An angle formed by a tangent line of the reference line and a perpendicular line passing through the origin in the image plane from the image obtained by the image pickup means based on the image pickup means different by 180 ° and the state detecting method of the robot arm according to claim 8. And a computing means for computing.

That is, a system for detecting the tilting state of the robot arm using the method for detecting the state of the robot arm according to claim 8 is realized.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION A robot arm state detection method and detection system according to the present invention will be described below in detail in the order of [Embodiment 1] to [Embodiment 10] with reference to the accompanying drawings.

[First Embodiment] (Structure of First Embodiment) FIG. 1 is an explanatory view showing the structure of an apparatus using the method for detecting the state of a robot arm according to the first embodiment. In the figure, 101 is a reference plane 1 described later.
A robot arm having a rotation axis that is perpendicular to 04 and rotates in the θ direction, 102 is attached to the tip of the robot arm 101 so that the axial direction and the image pickup direction match, and is an image pickup unit that is an image pickup device for automatic teaching. CCD camera as
Reference numeral 04 is a horizontal reference surface on which a directional marking 103 is provided.

(Operation of Embodiment 1) Next, the operation of the apparatus configured as described above will be described. The CCD camera 102 mounted on the tip of the robot arm 101 images the marking 103 on the reference surface 104. Further, the coordinates of the characteristic points of the obtained image of the marking 103 are obtained.

That is, when the robot arm 101 is rotated clockwise by an angle γ, as shown in FIG. 2, the detected coordinates (a ₀ , b ₀₎ before rotation of the marking 103 in the image 201 of the reference plane 104 are picked up. ), The angle α with the image X axis before rotation, the detected coordinates after rotation (a ₁ , b ₁ ), the angle with the image X axis before rotation β, and the robot arm 101 in the image 201. Assuming that the virtual reference coordinates of the rotation center of (x, y) are (x, y), their relationship is given by the following mathematical expression 1.

[0031]

[Equation 1]

Here, assuming that γ = β-α, the reference coordinates (x, y) to be detected are given by the following equation 2.

[0033]

[Equation 2]

Then, the position of the feature point to be detected is aligned with the above-referenced reference coordinates, and rotation and translational movements are performed, so that detection in the image plane is realized, and at the same time, the rotation axis of the robot arm 101 is used as a reference. The position detection can be performed.

[Second Embodiment] (Structure of Second Embodiment) FIG. 3 is an explanatory diagram showing a structure of an apparatus using a robot arm state detection method according to a second embodiment. This apparatus has a configuration in which a robot 301 having a second robot arm 302 is provided in addition to the configuration of FIG. 1 described in the first embodiment.

Since the other constituent elements and their functions are the same as those in the first embodiment, the same reference numerals as those in FIG. 1 are given and their explanations are omitted.

(Operation of Second Embodiment) Next, the operation of the apparatus configured as described above will be described. As shown in FIG. 3, the second robot arm 302 of the robot 301
When it is desired to detect the axis center of the rotation axis of the, the CCD camera 102 is used to mark the marking 103 on the reference surface 104 as shown in FIG.
Coordinates (x,
y).

Assuming that the required accuracy D of the optical system is D, the cell size is d, and the magnification is M, then M = D / d.

The distance between the image center coordinates (s, t) and the coordinates (x, y) to be detected is M {(s−x) ² + (t−y) ² } ^{1 as} seen from the robot 301. Given by ^{/ 2} .

Note that here, the detection target is captured within the image plane 201 as in the first embodiment, but the reference is the second robot arm 30 existing on the virtual plane.
It is the center of the rotation axis of 2.

[Third Embodiment] (Configuration of Third Embodiment) FIG. 5 is an explanatory diagram showing the configuration of a robot arm detection system according to a third embodiment. In addition to the configuration of FIG. 1 described in the first embodiment, this system serves as a mounting means that gives rotation around the axis of the robot arm 101 to the attachment / detachment portion of the CCD camera 102, the robot arm 101 and the CCD camera 102. The robot arm 101 is equipped with an attachment / detachment mechanism 501 and an image processing device 502 as an arithmetic means for calculating coordinates and angles from an image obtained from the CCD camera 102.
The inside of the attachment / detachment mechanism 501 is hollow, and the CCD camera 10
The cable of the CCD camera 102 does not interfere with the rotational movement even if the robot arm 101 does not have a rotating mechanism.

(Operation of Embodiment 3) Next, the operation of the system configured as described above will be described. Using the robot arm detection method described in the first or second embodiment, the rotation center axis of the attachment / detachment mechanism 501 is photographed by the CCD camera 102, detected in the captured image plane, and measured from the outside. By detecting the relative position between the rotation center axis of the attachable / detachable mechanism 501 and the robot arm 101, the axis of the robot arm 101 can be detected by the coordinates in the image plane.

[Fourth Embodiment] (Structure of Fourth Embodiment) FIG. 6 is an explanatory view showing a structure of an apparatus using a method for detecting a state of a robot arm according to a fourth embodiment. Here, the central axis of rotation of the robot arm 101 and a vertical line of the CCD camera 102 are aligned, and the CCD camera 1 is set with an arbitrary image pickup device in that line as the origin.
The image pickup direction of 02 is fixed vertically to the robot arm 101, and the radius is set to be perpendicular to the horizontal reference plane and the robot arm 10
A reference cylinder 601 having a distance from the rotation center of 1 to the tip of the imaging distance of the CCD camera 102 is installed.
A reference line is set inside 01 parallel to the circumference.

(Operation of Fourth Embodiment) Next, the operation of the apparatus configured as described above will be described. Here, FIG. 7 shows an image in which the reference line of the reference cylinder 601 in which the reference line is provided inside the cylinder in parallel with the circumference is imaged. Further, the relationship between the reference line and the imaging direction at that time is as shown in FIG.

In this, the rotation axis is set at an angle inclined from the x-axis by α and from the z-axis by θ, S ₀ is the reference line, and S ₁ is the imaging direction. At S ₁ . When the image is rotated by φ around the z-axis from the x-axis, the imaging direction becomes B. The tangent line of the reference line at that time is the plane R tangent to B of the tangent line of S ₀ in A.
Becomes a map to.

In FIG. 7, 701 is a perpendicular line passing through the origin,
Reference numeral 702 indicates a tangent to the reference line. As for the tangent line of the reference line, the tangent line of the reference line at the point B in FIG. 8 and the perpendicular line of the image are perpendicular to each other, but they exist twice when the robot arm 101 is rotated 360 °. Then, the case where the tangent line of the image is on the upper side is determined to be the tilt direction.

Here, the angle between the plane R of the tangent to the reference line and the horizontal direction of the CCD camera 102 can be detected by a simple coordinate calculation as shown in the following Equation 3, but the robot automatically advances while adjusting. It is easier to do. For example, θ =
When 15 ° and α = 20 °, the angle between the tangent to the reference line and the horizontal direction of the CCD camera 102 is as shown in FIG.

[0048]

[Equation 3] The tilting direction can be found by finding α and φ when is satisfied.

[Fifth Embodiment] (Structure of the Fifth Embodiment) Here, it is assumed that the apparatus shown in FIG. 6 having the same structure as that of the fourth embodiment is used.

(Operation of Fifth Embodiment) FIG. 10 is an explanatory view showing a method for detecting the state of the robot arm according to the fifth embodiment. If the distance between the tangent line of the reference line and the origin set in the image is obtained from the image as a and b, the diameter of the reference cylinder 601 is a known value because it is given as an imaging distance and a mechanical set value. Although it is set to 2r here, the angle θ is derived by the value of the following equation. That is, it is given by θ = sin ⁻¹ {(a + b) / 2r}.

[Sixth Embodiment] (Structure of Sixth Embodiment) FIG. 11 is an explanatory diagram showing a robot arm state detection system according to a sixth embodiment. Similar to Embodiments 4 and 5, the robot arm 101 has a tip C in which the imaging direction is perpendicular to the axial direction.
The CD camera 102 is fixed, and the reference cylinder 601 for tilt detection set vertically to the horizontal reference plane 104 is fixed.

That is, in the system according to the sixth embodiment, the reference cylinder 601 for tilt detection set vertically to the horizontal reference plane is fixed, and the central axis of rotation of the robot arm 101 and the vertical line of the CCD camera 102 are aligned. Is parallel to the robot arm 101 so that the CCD camera 102 can be attached to and detached from the robot arm 101 so that the axial direction is perpendicular to the imaging direction of the CCD camera 102. Further, it is assumed that an image processing device 502 (not shown) is connected to the outside as in FIG.

(Operation of Sixth Embodiment) Next, the operation of the system configured as described above will be described. The operation of the robot arm described in the fifth embodiment will be explained by the image processing apparatus 502 connected to the outside. Using the state detection method, calculate the angle between the tangent to the reference line and the vertical or horizontal direction in the image plane.

[Seventh Embodiment] (Structure of Seventh Embodiment) FIG. 12 is an explanatory diagram showing a structure of an apparatus using a robot arm state detection method according to a seventh embodiment. This apparatus is provided with a rotation mechanism 1201 for rotating the CCD camera 102 mounted on the tip of the robot arm 102 by 90 ° in the vertical and horizontal directions, and has vertical and horizontal reference planes 1202a and 1202b.
Of the two reference surfaces 1202a and 122
02b is provided with markings 1203a and 1203b, respectively.

(Operation of Embodiment 7) Next, the operation of the apparatus configured as described above will be described. The CCD camera 102 mounted on the robot arm 101 is rotated 90 ° by a rotating mechanism 1201 to change the imaging direction by 90 ° and the marking 120 on the reference planes 1202a and 1202b.
3a and 1203b are imaged. An image obtained as a result of the imaging and superimposing is an image 1301 shown in FIG. That is, in FIG. 13, the tilt angle of the angle θ is detected.

[Eighth Embodiment] (Structure of Eighth Embodiment) FIG. 14 is an explanatory diagram showing the structure of a robot arm detection system according to the eighth embodiment. This system uses the detection method described in the seventh embodiment.

That is, as shown in FIG. 14, the rotation axis of the attachment / detachment mechanism consisting of the motor fixed to the end of the robot arm 101 of the system shown in FIG. 5 is fixed so as to be perpendicular to the rotation axis of the robot arm 101. Further, a system in which a CCD camera 102 is attached to a rotation mechanism 1201 so that the image pickup direction can be changed perpendicularly to the rotation axis of the robot arm 101, and reference planes 1202a and 1202b are installed at positions where the image pickup distance can be maintained in the vertical and horizontal directions. Has become. Further, the image processing device 50 is externally provided as in FIG.
2 (not shown) are connected.

(Operation of Eighth Embodiment) Next, the operation of the system configured as described above will be described. As described in the seventh embodiment, the CCD camera 102 mounted on the robot arm 101 is rotated by 90 ° by the rotation mechanism 1201 and the imaging direction is changed by 90 °, and the reference plane 12 is changed.
Markings 1203a and 120 on 02a and 1202b
3b and are imaged. Then, a superimposed image as shown in FIG. 13 is obtained, the tilt angle of the angle θ is detected, and mechanical tilt correction is executed.

[Ninth Embodiment] (Structure of Ninth Embodiment) FIG. 15 is an explanatory diagram showing the structure of an apparatus using a robot arm state detection method according to a ninth embodiment. This device is different from the above-described FIG. 11 in that CCD cameras 1501a and 1501 each have an imaging direction different by 180 ° from the rotation axis direction of the robot arm 101.
1b is fixed.

(Operation of Ninth Embodiment) Next, the operation of the apparatus configured as described above will be described. Reference cylinder 6
The reference line 01 is imaged, and the angle between the tangent of the reference line and the horizontal direction in the imaging plane is compared by shifting one of the angles by 180 ° in phase.

As shown in FIG. 16, the robot arm 101
And the rotation axis are coincident with each other and have a tilt component, if one phase is shifted by 180 °, the angle formed by the mapping of the tangent line at point A to R and the tangent line at the point part is as shown in FIG. Match exactly.

Further, FIG. 18 shows a case where the robot arm 101 does not coincide with the rotation axis and the rotation axis is oriented vertically downward. FIG. 19 shows individual angle changes imaged by the two CCD cameras 1501a and 1501b. Show. Furthermore, FIG.
The robot arm 101 and the rotation axis do not match 0,
In addition, the case where the rotation axis does not match vertically downward is also shown.
FIG. 21 shows individual changes in angle captured by the two CCD cameras 1501a and 1501b.

Therefore, in FIG. 19 and FIG.
Since the height of the tangent line obtained in the image is different in the image plane,
The results of both are staggered. Then, the error factor is determined based on these results.

[Embodiment 10] (Structure of Embodiment 10) FIG. 22 is an explanatory diagram showing the structure of a robot arm detection system according to Embodiment 10, and a system structure based on Embodiment 9 above. And only the main part is shown here. That is, the imaging direction is 180 ° at the tip of the robot arm 101.
Different CCD cameras 1501a and 1501b are mounted.

(Operation of Tenth Embodiment) Next, the operation of the system configured as described above will be described. As described in the ninth embodiment, the reference line of the reference cylinder 601 is imaged, and the angle formed by the tangent line of the reference line and the horizontal direction in the imaging plane is compared by shifting one of the angles by 180 ° in phase. ，
The same processing as described above is executed.

[0066]

[0067]

As described above , according to the method for detecting the state of the robot arm according to the present invention (claim 1 ), since the optical magnification is used as a known value, the center of rotation of the axis exists in the image plane. Even without doing so, the center of rotation is detected as coordinates in a virtual image plane that is an extension of the image plane, and the position of the detection target is detected and positioned relative to the rotation center of the axis. Can be corrected with high accuracy.

Further, according to the robot arm detection system of the present invention (claim 2 ), even if the robot arm is not provided with a rotation mechanism, a rotation mechanism whose rotation center position is known can be used as the axis of the robot arm. Since the detection method according to claim 1 is provided on the mounting portion, the reference coordinates of the image can be determined only by a mechanical error factor that can be measured from the outside without considering the positioning error of the image pickup device of the image pickup means or the design intersection. Obtainable.

Further, according to the method for detecting the state of the robot arm according to the present invention (claim 3 ), when it is expected that the axial direction of the robot arm and the rotation axis coincide with each other, a rotation mechanism of the axis is used. The angle of the robot arm axis can be detected because the image pickup means for picking up the image in the direction perpendicular to the axial direction detects the angle parallel to the horizontal row in the image plane.

[0070] Further, according to the method for detecting the state of the robot arm according to the present invention (Claim 4), fifth claim 3
The distance between the origin and the reference line in the tilt angle direction detected in the process of step 1 is stored, and the distance between the origin and the reference line in the image plane when the robot arm is rotated 180 ° about the axis is detected. However, since this is compared with the stored value, it is possible to detect the tilt angle of the robot arm while ignoring the slight change in the imaging distance due to tilt.

According to the robot arm detection system of the present invention (claim 5 ), the above-mentioned claim 3 or 4 can be used.
A system for detecting the tilting angle of a robot arm using the method for detecting the state of a robot arm described in 1. is realized.

Further, according to the method for detecting the state of the robot arm according to the present invention (claim 6 ), when the tilting direction is known, the tilting angle in any direction of the robot arm is detected, so that the mechanical tilting is performed. Can be corrected.

Further, according to the robot arm detection system of the present invention (claim 7 ), a system for detecting the tilt angle of the robot arm using the robot arm state detection method according to claim 6 is realized. To do.

Further, according to the method for detecting the state of the robot arm according to the present invention (claim 8 ), since each step described in claim 8 is used, it is determined whether the robot arm and its rotation axis match. Also, it is possible to determine whether the rotation axis and the vertically downward direction match.

Further, according to the robot arm detection system of the present invention (claim 9 ), a system for detecting a tilting state of the robot arm using the robot arm state detecting method according to claim 8 is realized. To do.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an apparatus using a robot arm state detection method according to a first embodiment.

FIG. 2 is an explanatory diagram showing a method for detecting a state of a robot arm according to the first embodiment.

FIG. 3 is an explanatory diagram showing a configuration of an apparatus using a robot arm state detection method according to a second embodiment.

FIG. 4 is an explanatory diagram showing a method for detecting a state of a robot arm according to a second embodiment.

FIG. 5 is an explanatory diagram showing a configuration of a robot arm detection system according to a third embodiment.

FIG. 6 is an explanatory diagram showing a configuration of an apparatus using a robot arm state detection method according to a fourth embodiment.

FIG. 7 is an explanatory diagram showing an image when a reference line of a reference cylinder in which a reference line is provided inside the cylinder according to the fourth embodiment in parallel with the circumference is imaged.

FIG. 8 is an explanatory diagram showing a tilt detection principle according to the fourth embodiment.

FIG. 9 is an explanatory diagram showing an image picked up by the CCD camera according to the fourth embodiment.

FIG. 10 is an explanatory diagram showing a method for detecting a state of a robot arm according to a fifth embodiment.

FIG. 11 is an explanatory diagram showing a robot arm state detection system according to a sixth embodiment.

FIG. 12 is an explanatory diagram showing a configuration of an apparatus using the robot arm state detection method according to the seventh embodiment.

FIG. 13 is an explanatory diagram showing a method for detecting a state of a robot arm according to the seventh embodiment.

FIG. 14 is an explanatory diagram showing a configuration of a robot arm detection system according to an eighth embodiment.

FIG. 15 is an explanatory diagram showing a method for detecting a state of a robot arm according to the ninth embodiment.

FIG. 16 is a robot arm and C according to the ninth embodiment.
It is explanatory drawing which shows the rotation state example (the 1) of a CD camera.

FIG. 17 is an explanatory diagram showing an angle formed by mapping a tangent line at a point A to R and a tangent line at a point B in the state shown in FIG. 16;

FIG. 18 is a robot arm and C according to the ninth embodiment.
It is explanatory drawing which shows the rotation state example (the 2) of a CD camera.

19 is an explanatory diagram showing individual angle changes captured by the two CCD cameras in FIG.

FIG. 20 is a robot arm and C according to the ninth embodiment.
It is explanatory drawing which shows the rotation state example (the 3) of a CD camera.

21 is an explanatory diagram showing individual angle changes captured by the two CCD cameras in FIG. 20. FIG.

FIG. 22 is an explanatory diagram showing the configuration of the robot arm detection system according to the tenth embodiment.

[Explanation of symbols]

101 robot arm 102 1501a, 1501b CCD camera 103,1203a, 1203b marking 104, 1202a, 1202b Reference plane 201 Reference plane image 501 attachment / detachment mechanism 502 image processing apparatus 601 Reference cylinder 701 Vertical line in the reference plane 702 tangent to the reference line 1201 rotation mechanism

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Claims (9)

(57) [Claims] 1. A method of detecting the position of a detection target from an image picked up by an image pickup means attached to the tip of a robot arm, the method for detecting the position of a detection target, the horizontal direction having directional markings. The image pickup direction of the image pickup means is fixed to the tip end in the vertical direction on the rotation axis of the robot arm with respect to the reference plane, the marking image is picked up by the image pickup means at a known optical magnification, and the characteristic point of the imaged marking The first step of obtaining the coordinates of the robot arm, the second step of obtaining the direction of the marking image obtained by the first step, and the axis of the robot arm based on the results of the first step and the second step. From the third step of rotating the robot arm around an appropriate angle, and the posture of the marking and the optical magnification before and after the rotation of the robot arm, Fourth step and the state detecting method of a robot arm, characterized in that it comprises a for detecting the rotational center of the serial robot arm by a coordinate in the virtual extended captured image. 2. An image pickup means mounted on the tip of a robot arm for picking up a directional marking provided on a horizontal reference plane, and the image pickup means being detachable from the robot arm,
And a mounting means having a mechanism for rotating around the axis of the robot arm, and a computing means for computing coordinates and angles from an image obtained by the imaging means, wherein the computing means comprises: 1 based on the state detecting method of a robot arm according to, said detecting a center of the mounting means as the coordinate in the image plane, to perform the offset correction of said mounting means and said robot arm by using a detected value Robot arm detection system. 3. A state detecting method of a robot arm for detecting a position of an object to be detected and positioning from an image picked up by an image pickup means attached to a tip of a robot arm, comprising: a rotation center axis of the robot arm; The first step of aligning the image pickup element in a vertical line and fixing the image pickup direction vertically to the robot arm with an arbitrary element in the line as an origin; and rotating the robot arm with a radius perpendicular to a horizontal reference plane. A second step of installing a cylinder having a distance from the center to the image pickup distance of the image pickup means and setting a reference line parallel to the circumference inside the cylinder, and a rotation axis of the robot arm and the image pickup device. Teach the robot arm so that the intersection with a line extending perpendicularly from the origin to the axis of rotation of the robot arm is at the center of the cylinder and at the height of the reference line. Of the reference line imaged in the fourth step, and a fourth step of rotating the robot arm around an axis while keeping a known angle and arbitrarily imaging the reference line. The angle between the tangent at the intersection with the vertical line passing through the origin on the image plane and the vertical line of the image is 9
A fifth step of detecting the angle at which the angle becomes 0 ° and detecting the tilting angle of the robot arm, the method of detecting the state of the robot arm. 4. The distance between the origin and the reference line in the tilt angle direction detected in the fifth step according to claim 3 is stored, and the robot arm is rotated by 180 ° about an axis.
A method for detecting a state of a robot arm, which rotates, detects a distance between an origin in a plane of an image and a reference line, compares the detected value with the stored value, and detects a tilt angle of the robot arm. . 5. A reference cylinder for tilt detection which is set and fixed vertically to a horizontal reference plane, and an image pickup means which is fixed to the tip of the robot arm with the image pickup direction and the axial direction perpendicular to each other. The mounting means having a mechanism for rotating the robot arm so that a central axis of rotation of the robot arm and a vertical line of the imaging means are parallel to each other and the axial direction and the imaging direction are perpendicular to each other, and the robot according to claim 3 or 4. A calculation means for calculating an angle formed by a tangent line of the reference line and a perpendicular line passing through the origin in the image plane from the image obtained by the image pickup means, based on the arm state detection method. Robot arm detection system. 6. A method for detecting the position of a detection target object based on an image picked up by an image pickup means mounted on the tip of a robot arm, comprising: a horizontal first reference plane and the first reference plane; Is provided on each surface of the second reference surface having a known angle with respect to each other, is provided with directional and equidistant markings, and is provided on the horizontal first reference surface by the image pickup means. First
A first step of imaging the marking on the reference surface, a second step of imaging the marking on the second reference surface by the imaging means, and two markings obtained by the first step and the second step. Find the coordinates of the image feature points,
Further, from the third step of obtaining the marking direction, the fourth step of rotating the central axis of the robot arm perpendicular to the axial direction at an appropriate angle, and the marking posture before and after the rotation of the robot arm A robot arm state detection method, comprising: a fifth step of detecting and correcting the tilt angle in the second reference plane direction. 7. A horizontal first reference plane having directionality on each surface and marking at equidistant positions, and a second reference plane having a known angle with respect to the first reference plane. An image pickup means attached to the tip of the robot arm for picking up images of the first reference plane and the second reference plane; and the image pickup means obtained based on the robot arm state detection method according to claim 6. A detection system for a robot arm, comprising: a calculation unit that calculates coordinates and angles from the captured image. 8. A method for detecting the state of a robot arm, which detects the position of a detection target from images picked up by two image pickup means attached to the tip of the robot arm and having different image pickup directions of 180 °, respectively. When the angle formed by the tangent line of the reference line and the perpendicular line passing through the image plane detected by the two image pickup means is 180 ° out of phase due to the displacement of the rotation angle of the robot arm, the rotation axis of the robot arm is A step of determining that the robot arms are coincident with each other and deviated from the vertically downward direction; and that the intersection of the reference line and the perpendicular of one of the two image pickup means is higher than the other in the screen, If the tangent to the reference line is vertical, the rotation axis of the robot arm and the robot arm do not match, and the rotation axis is determined to be vertically downward. Otherwise, it is determined that the rotation axis of the robot arm does not match the robot arm, and the rotation axis does not match vertically downward. 6. Detection method of robot arm. 9. The robot according to claim 8 , wherein a reference cylinder for tilt detection which is set / fixed vertically to a horizontal reference plane, imaging means having imaging directions different from each other by 180 ° at the tip of the robot arm, A calculation means for calculating an angle formed by a tangent line of the reference line and a perpendicular line passing through the origin in the image plane from the image obtained by the image pickup means, based on the arm state detection method. Robot arm detection system.