JPH0440308A - Normal direction detector - Google Patents

Abstract

PURPOSE:To securely and accurately detect the normal direction of a measurement surface by receiving position information about a base member from a control means, and calculating a normal direction from the three-dimensional position of the base member when a photodetector photodetects reflected light. CONSTITUTION:The base member 12 is provided to the turret of a robot and the image pickup head part 21a of a CCD camera 21 is provided at the center part on the turret-side end surface of the member 12 so that the center axis M is matched with the normal N of the member 12; and a projector 22 is provided at one end part of the member 12 at a specific angle theta to the member 12 in a plane containing the axis M and the photodetector 23 is provided at the other end part of the member 12 at the angle theta on the plane containing the axis M symmetrically with the projector 22. Then a paint defect PD in an inspection area ANP is detected from image data picked up by the camera 21, projection light 26 is projected on the defect PD, and the position of the member 12 is so controlled that reflected light 27 is photodetected in the center of the photodetector 23; and the normal direction of the defect PD is detected from the three-dimensional position of the member 12 and the normal direction of the defect PD on a vehicle body B is accurately detected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a normal direction detection device, and in particular detects an object on a curved measurement surface and detects the normal direction of the measurement surface including the object. The present invention relates to a normal direction detection device.

[Prior art]

BACKGROUND ART In recent years, automation of tasks that were conventionally performed manually has been widely promoted, and at the same time, various technologies for automatically detecting physical quantities related to workpieces such as parts have been developed and put into practical use.

For example, in addition to technology that detects the position, shape, or dimensions of a workpiece, there is also technology that detects objects such as machining marks or defects on the measurement surface of the workpiece, and also detects the normal direction of the measurement surface that includes the object. Is required.

For example, JP-A-63-154908 and JP-A-6
No. 3-169502 describes a normal direction detection device that detects the normal direction of a measurement surface in a non-contact manner.

[Problem to be solved by the invention]

The normal direction detection devices described in each of the above-mentioned publications are all equipped with a distance sensor having a light projecting section that projects a projection light onto a measurement surface, a light receiving section that receives reflected light from the measurement surface, etc. This method uses triangulation to detect the normal direction of the measurement surface.If the measurement surface is flat, it is possible to detect the normal direction, but if the measurement surface is a flat surface, such as the surface of a car, If the surface has various curved shapes, it may be difficult for the reflected light to enter the light receiving section, making it impossible to detect the normal direction.
There is a problem that detection accuracy is significantly reduced.

An object of the present invention is to provide a normal direction detection device that can detect an object on a curved measurement surface and also detect the normal direction of the measurement surface reliably and with high precision.

[Means to solve the problem]

A normal direction detection device according to the present invention is a normal direction detection device for detecting an object on a measurement surface and a normal direction of the measurement surface including the object, and is provided on a base member. an imaging means for capturing an image of the measurement surface through an imaging head section, and a projector that projects an image toward an object on the measurement surface from a projector provided at a predetermined angle on the base member in a plane including the central axis of the imaging head section; a light projecting means for projecting light;
Receives the projected light reflected on the measurement surface through a light receiver installed on the base member tilted at the predetermined angle so as to be symmetrical to the projector with respect to the center axis within a plane including the center axis of the imaging head. a driving means for three-dimensionally moving and driving the base member; and a detecting means for receiving image data from the imaging means and detecting an object;
a control means for controlling the driving means so that the light receiver receives the reflected and projected light in response to an output from the light receiving means; and a control means for receiving the position information of the base member from the control means and receiving the reflected and projected light at the light receiver. and calculation means for calculating the normal direction from the three-dimensional position 1 of the base member.

[Effect]

In the normal direction detection device according to the present invention, when detecting an object on the measurement surface and detecting the normal direction of the measurement surface, the imaging head section of the imaging means provided on the base member can image the measurement surface. It is set at a predetermined imaging position, and in that state the measurement surface is imaged by the imaging means.

Next, the object on the measurement surface is detected by the detection means that receives the image data from the imaging means.

Next, based on the position data of the object detected by the detection means, projection light is projected from the light projector of the light projection means onto a region of the measurement surface including the object.

Next, in response to the output from the light receiving means, the driving means is controlled by the control means so that the light receiver receives the reflected projection light, and the base member is driven to move.

Next, the calculation means that receives the position information of the base member from the control means calculates the normal direction of the measurement surface from the three-dimensional position of the base member when the reflected projection light is received by the light receiver.

In this way, the imaging head section of the imaging means, the emitter, and the light receiver are provided in a predetermined positional relationship on the base member that is moved and driven by the driving means, and the detection means detects the object based on the image data of the measurement surface including the object. is detected, the projector emits the projection light onto the measurement surface including the target object, and the calculation means detects the normal direction of the measurement surface from the three-dimensional position of the base member when the light receiver receives the reflected projection light. Therefore, the object and normal direction of the curved measurement surface can be detected reliably and with high precision.

Furthermore, the target object can be detected based on the image data from the imaging means, and the projection light can be projected onto the measurement surface including the target object.
The imaging means can be effectively utilized and the configuration of the normal direction detection device can be simplified.

〔Effect of the invention〕

According to the normal direction detection device according to the present invention, the above [effects]
As explained in the section above, the imaging head section of the imaging means, the light projecting means, and the light receiving means are provided in a predetermined positional relationship on the base member that is moved and driven by the driving means, and the imaging head part of the imaging means, the light emitting means, and the light receiving means are provided in a predetermined positional relationship, and the image data of the measurement surface including the object is measured. The detection means detects the object, the projector emits the projection light onto the measurement surface including the object, and the calculation means calculates the angle of the measurement surface from the three-dimensional position of the base member when the light receiver receives the reflected projection light. Since the linear direction is detected, the object and normal direction of the curved measurement surface can be detected reliably and accurately, the imaging means can be used effectively, and the configuration of the normal direction detection device can be simplified. to be able to become
Effects such as this can be obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The normal direction detection device of this embodiment is an application of the present invention to a normal direction detection device for detecting paint defects on an automobile body and detecting the normal direction of a vehicle body surface including paint defects. .

As shown in Fig. 1, a reference stand 1 is provided on the floor for positioning and placing the vehicle body B, and at a predetermined position on the right side of the reference stand 1 there are two telescopic A six-axis articulated robot 10 having an axis and four rotation axes is provided,
A control unit 30 is provided at the rear of the robot 10 to drive and control the robot 10 and to process image signals from an imaging device 20 provided on the robot 10.

To explain the imaging device 20, as shown in FIGS. 1 to 3, a turret 11 attached to the wrist 10a of the robot 10 is provided with a base member 12 made of a rectangular parallelepiped plate member. At the center of the end surface of the member 12 opposite to the talent, an imaging head 21a of a CCD camera 21 is mounted, with the central axis M aligned with the normal N of the base member 12.
is provided at one end of the base member 12, and a central axis M is provided at one end of the base member 12.
A projector 22 having a built-in collimator lens is provided on the base member 12 at a predetermined angle θ in a plane including
A light receiver 23 is provided at the other end of the base member 12 and is tilted at a predetermined angle θ so as to be symmetrical with the light projector 22 with respect to the center of the plane including the central axis M.

Further, on the end surface of the base member 12 on the turret side, for example, H
Laser light generator 24 consisting of eNe laser and prism 2
5 is provided, and the laser beam output from the laser beam generator 24 is supplied to the projector 22 via a prism, where the projector 22 forms parallel projection light 26 of a predetermined diameter and projects it onto the vehicle body B.

The light receiver 23 is composed of nine phototransistors S, -S, as shown in FIG. The reflected projection light 27 is received by any one of them.

Next, the control unit 30 will be explained with reference to FIG. 5.

The control unit 30 operates a control section 31 for driving and controlling the robot 10, a control program storage section 32, a driving section 33, an input interface 34, a CCD camera 21, and a laser beam generator 24, and controls the CCD camera 2
A microcomputer 35 for processing one image signal and a signal from the light receiver 23, and an image data storage section 36.
, an input interface 37, an output interface 38, etc.

The control section 31 includes a CPU (central processing unit) and a RAM.
(random access memory), etc., and drives and controls the servo motors 13 of each axis of the robot IO via the drive unit 33 according to the robot control program stored in the control program storage unit 32. A feedback signal from a low-return encoder 14 attached to the servo motor 13 is input via an input interface 34, and control data from a microcomputer 35 is also input.

The microcomputer 35 includes a CPU, a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and the ROM contains a control program for normal direction detection control, which will be described later, and the turret 1 included therein.
1 and base member 12, and shape data of the vehicle body B are stored.

To explain the shape data of the vehicle body B using the bonnet 2 as an example, as shown in FIG. XY fixed to the floor when placed
The three-dimensional coordinate values of four points Q, ~Q4 that partition each inspection area AN in the Z coordinate system (see Figure 1) are set in advance, and the coordinate values are stored in the ROM as the shape data of the bonnet 2.
is stored in. The same applies to the outer surfaces of the vehicle body other than the bonnet 2.

The relative position data of the base member 12 includes a CCD camera 21 provided on the turret 11 and the base member 12 with respect to a predetermined reference point of the wrist portion 10a of the robot 10.
, relative position data of specifications regarding the light emitter 22 and the light receiver 23 are stored.

The image data storage section 36 is provided with an image data memory for storing the image data inputted to the microcomputer 35 from the input interface 37, and the input interface 37 contains noise from the image signal inputted from the CCD camera 21. The output interface 38 is provided with a filter that removes the image signal and an A/D converter that converts the image signal into A/D, and the output interface 38 drives the laser light generator 24 and the CCD camera 21 to turn on and off based on command signals from the microcomputer 35. There is a driver for this. Incidentally, reference numeral 39 is an operation panel for starting and stopping each program, setting the initial posture of the robot 10, and the like.

Next, a flowchart of a routine for detecting paint defects PD and normal direction detection control will be described based on the flowchart in FIG. 7 with reference to FIGS. 6, 8, and 9. However, in Fig. 7, 5t (i=1.2.3,
) indicates each stem knob.

When the vehicle body B is placed on the reference stand 1 and an inspection start command is input from the operation panel 39, control starts, clearing the RAM memory and image data memory of the control unit 30, and starting the counter N that counts the number of inspection areas AN. Initialization such as initial value setting is executed (Sl), and the coordinate values of four points Q1 to Q4 of the inspection area AN (N=1) of the vehicle body B to be inspected first are read, and the inspection area AN is read from the coordinate values. A plane ANP (see FIG. 3) approximately parallel to the inspection area is calculated from the coordinate values of the center point Qc and the coordinate values of the center point Qc and points Q1 to Q2 (S2).

Next, the robot 10 is driven based on the coordinate values of the center point Qc, and the base member 12 is moved so that the CCD camera 21 is at a predetermined height above the inspection area AN and the base member 12 is parallel to the plane ANP. The imaging position is set at , and the positional information of the wrist 10a of the robot 10 at that time is stored (S3).

Next, the CCD camera 23 is activated and the inspection area AN is imaged (S 4 ).The image signal for one screen obtained in the above imaging is output to the input interface 37, and the CCD camera 21 is 2
Each image signal corresponding to all 56×256 pixels is A
/D conversion into 256-step digital image data, which is supplied to the microcomputer 35 (S
5).

As shown in FIG. 8, in the microcomputer 35, the average value of image data for all pixels and upper and lower threshold values for determining paint defects PD (these are determined by adding or subtracting a predetermined value to the average value) (required by doing)
is calculated (S5).

Next, using the above threshold value, the image data is subjected to binarization processing as shown in FIG. 9, and the binarized image data is stored in the image data storage section 36 (S6). In the binarization process, as shown in Figure 9, if each image data is above the upper limit threshold or below the lower limit threshold, the painting defect P
If it is D, "1" is assigned, and "0" is assigned to anything else.

Next, using 256x256 binarized image data,
The presence or absence of a coating defect PD is detected by detecting "1" in the binary image data (S7).

Next, it is determined whether there is a paint defect PD in the area AN (S8), and if there is no paint defect PD, the counter N is incremented (39), and the steps after S1 are executed for the area AN to be inspected next. Ru. On the other hand, if there is a paint defect PD, the position information of the wrist 10a of the robot 10 set in S3 (position information of the camera 21),
The position of the painting defect PD in the XYz coordinate system is calculated and stored using the relative position data and the position information of the painting defect PD on the screen obtained using the binarized image data, and the position of the painting defect PD is calculated and stored. The coordinate values of the center PDc are calculated and stored (S10).

Next, based on the coordinate values of the center PDc, the base member 12
is driven to move, and the imaging position is set such that the center PDc is located on the central axis M of the CCD camera 21, the CCD camera 23 is at a predetermined height from the vehicle body B, and the base member 12 is parallel to the plane ANP. is corrected, and the correction data of the position information of the wrist portion 10a of the robot 100 is stored (Sl
l).

Next, the laser beam generator 24 is activated, and as shown in FIG. 3, the projection light 26 is projected onto the coating defect PD. (51
2) Next, it is determined whether the reflected projection light 27 has been received by the light receiver 23 based on the signals input from each phototransistor SI to S9 of the light receiver 23 to the microcomputer 35 via the input interface 37 (S13 ). That is, when the reflected projection light 27 is received by any one of the phototransistors S and -S*, a signal of, for example, "1" is input to the microcomputer 35 corresponding to that phototransistor. "0" is input corresponding to the other phototransistors.

The reflected projection light 27 is transmitted to the phototransistor S1 of the light receiver 23.
~S, when the light is not received, the base member 12 is swung in a predetermined manner around the α-axis and β-axis parallel to the two sides of the base member 12, respectively, as shown in FIG. The amount of rocking is stored as correction data for the position information of the wrist portion 10a of the robot 10 (514). After that, receiver 2
Steps 313 and S14 are repeated until the reflected projection light 27 is received in step 3. However, in this case as well, the CCD camera 21 is held at a predetermined height position relative to the vehicle body B.

On the other hand, when the reflected projection light 27 is received by the light receiver 23, it is determined based on the signal input to the microcomputer 35 whether the reflected projection light 27 has been received by the phototransistor S5 located at the center of the light receiver 23. (315)
. If the reflected projection light 27 is not received by the phototransistor S, the deviation of the reflected projection light 27 from the fan 1-1-transistor S5 is detected from the signal of the phototransistor that received the reflected projection light 27, and this Based on the detected amount, the base member 12 is swung in a predetermined manner so that the reflected projection light 27 is received by the phototransistor S5 in the same manner as in step 14.
It is stored as correction data for the position information of 0a (S16
).

On the other hand, when the reflected projection light 27 is received by the phototransistor S5, the base member (Tsumari, turret 11)
12 and the painting defect PD are parallel to each other, therefore, the position data of the wrist 10a of the robot 10 set and stored in S3, the relative position data, Sll, 14 and S
], The normal direction of the paint defect PD is calculated based on the correction data regarding the position of the wrist portion 10a corrected in step 6, and the result is stored (S17).

Next, based on the data on the normal direction and defect position of the painting defect PD, the axis of the grinding wheel 13 mounted on the turret 11 is parallel to the normal direction of the painting defect PD, and the axis is in the direction of the painting defect PD. The position of the turret 11 is controlled so as to correspond to the center, and the painting defect P is moved along the normal direction of the painting defect PD.
The grinding wheel 13 is moved to D, and then the grinding wheel 13 is rotationally driven by an electric motor (the path shown in the figure) provided in the turret 11.
The coating defect PD is completely polished (S18).

Therefore, the paint on the vehicle body B outside the paint defect PD and the vehicle body B are not damaged by the grindstone 13.

When the polishing of the paint defect PD is completed, it is then determined whether all inspections of a predetermined number of inspection areas AN have been completed (S1
9) If the inspection is not completed, the counter N is incremented and steps 32 to 319 are repeated until the inspection of all inspection areas AN is completed.

In this way, the paint defect PD in the inspection area AN is detected from the image data of the image captured by the COD camera 21, and the projection light 26 is projected onto the paint defect PD, and the reflected projection light 27 is sent to the center of the light receiver 23. The position of the base member 12 is controlled so that the light is received at the center of the light receiver 23, and the normal direction of the painting defect PD is detected from the three-dimensional position of the base member 12 when the light is received at the center of the light receiver 23. The normal direction of the paint defect PD on the vehicle body B can be detected reliably and with high precision. Furthermore, since the paint defect PD can be detected based on image data from the COD camera 21 and the projection light 26 can be projected onto the paint defect PD, the COD camera 21 can be effectively utilized and the configuration of the normal direction detection device can be simplified. You can. Furthermore, the normal direction detection device can automate inspection and repair work that requires skill, and improve productivity.

Note that the diameter of the luminous flux of the projection light 26 may be increased to project the light onto the area including the coating defect PD.

In this case, the light receiver 23 may be composed of one phototransistor.

In addition, if the reflected projection light 27 is diffusely reflected or attenuated due to the shape of the paint defect PD, the projection light 27 may be affected by the paint defect PD.
The normal direction may be detected by projecting the projection light 26 onto the vehicle body B in the vicinity of the paint defect PD without projecting the light 26.

In addition, a CCD is used instead of the phototransistors S1 to S.
It is also possible to configure the light receiver 23 with an element or an optical fiber array, and convert the reflected projection light 27 received by the CCD element or optical fiber into an electrical signal at the input interface 37.

Furthermore, it goes without saying that the above-mentioned normal direction detection device can be applied not only to the inspection of painting of vehicle bodies but also to the assembly and processing of various parts, the inspection of products, and the like.

[Brief explanation of the drawing]

1 to 9 show embodiments of the present invention, in which FIG. 1 is a perspective view of a normal direction detection device, FIG. 2 is a schematic perspective view of an imaging device, and FIG. 3 is a front view of the imaging device. 4 is an explanatory diagram of the configuration of the light receiver, FIG. 5 is a block diagram of the control unit, FIG. 6 is a plan view of the front of the vehicle body, FIG. 7 is a flow chart of the normal direction detection control routine, and FIG. The figure is an explanatory diagram showing the level of image data, and FIG. 9 is an explanatory diagram of binarized image data of an image including paint defects. B...Vehicle body, PD...Painting defect, M...Center axis,
10...Robot, 12...Base member, 2
1. COD camera, 21a -- Imaging head section,
22... Emitter, 23... Light receiver, 24... Laser light generator, 25... Prism, 26... Projection light, 27
...Reflected projection light, 30...Control unit.

Claims (1)

[Claims] (1) A normal direction detection device for detecting a target object on a measurement surface and the normal direction of the measurement surface including the target object, which measures through an imaging head provided on a base member. an imaging means for capturing an image of the surface; and a light projecting means for projecting light toward an object on the measurement surface from a projector provided on the base member at a predetermined angle in a plane including the central axis of the imaging head. and projection light reflected on the measurement surface via the light receiver provided on the base member tilted at the predetermined angle so as to be symmetrical to the projector with respect to the center axis within a plane including the center axis of the imaging head. a driving means for three-dimensionally moving and driving the base member; a detecting means for receiving image data from the imaging means and detecting an object; and a light receiving means for receiving an output from the light receiving means. a control means for controlling the driving means so that the reflected projection light is received by the receiver; and a control means for controlling the driving means so that the reflected projection light is received by the receiver; 1. A normal direction detection device comprising: calculation means for calculating a normal direction.