JPH055628B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to teaching in painting and welding operations, deburring operations, three-dimensional sewing operations, and various operations that require the use of industrial robots to move along curved surfaces. The present invention relates to a non-contact curved surface profiling sensor that is used when carrying out such applications.

[Prior Art] When performing the various operations mentioned above, it is effective to make the heads, etc. used for those operations move in a non-contact manner with respect to the target surface. It is necessary to detect the relative direction and distance between the head and the target surface.

Conventionally, as a sensor used for such detection, for example, a large number of light emitting diodes (LEDs) are arranged in a ring, the light from those LEDs is irradiated onto a target surface, and the light formed on the target surface is detected. A sensor is known that detects information on the relative inclination and position between the LED array surface and the target surface from a figure, that is, from a deformation of a circle.

However, such sensors require a large number of
Since it uses LEDs, it not only has a complicated hardware configuration, but also has the disadvantage that information processing is complex and time-consuming.

[Problems to be Solved by the Invention] An object of the present invention is to provide a non-contact curved surface profiling sensor for use in the various operations mentioned above, which has a simple configuration and can process information at high speed. be.

[Means for Solving the Problems] In order to achieve the above object, the non-contact curved surface tracing sensor of the present invention directs three spot rays onto the surface to be controlled in a direction in which they diverge from one point or converge on one point. A light receiving unit that receives the emitted light source and the reflected light of three spot light points formed on the target surface through a lens system, and detects the coordinate information of each light spot on the target surface, and outputs from the light receiving unit. and an arithmetic processing circuit that calculates the relative direction and distance between the light receiving section and the target surface based on the coordinate information.

[Operation] The three spot light rays emitted from the light source form three spot light points on the target surface, and their positions are determined according to the relative direction and distance between the light source and the target surface. detected in the That is, the reflected light from the three spot light points enters the light receiving section through the lens system and forms an image, and the coordinate information on the light receiving surface is input from the light receiving section to the arithmetic processing circuit. Furthermore, the arithmetic processing circuit calculates the relative direction and distance between the light receiving section and the target surface based on the coordinate information. The output of this arithmetic processing circuit is input to a drive control circuit, and is compared with a preset reference value, and drive control is performed to move the light receiving section together with the light source so that they match. Then, the light source is controlled to follow the target surface.

[Effects of the Invention] As described above, according to the sensor of the present invention, the three spot beams are emitted so as to diverge from one point or so as to converge on one point.
By simply receiving the reflected light from the target surface of these spot rays through a lens system, the relative direction and distance between the light source and the light receiving section and the target surface can be detected, and therefore, with a simple configuration. Furthermore, information processing can be performed easily and at high speed.

[Embodiment] In the embodiment of the present invention shown in FIG. 1, 1 is a drive device, 2 is a light source/sensor section supported by the drive device, 3 is a target surface of the tracing operation, and the target surface 3 is The light source/sensor unit 2 is equipped with equipment for performing various tasks through tracing movements. The drive device 1 is configured with an arm mechanism or the like having 5 to 6 degrees of freedom, so that the light source/sensor section 2 can be relatively freely displaced facing the target surface 3 of the movement, thereby allowing both The configuration is such that a tracing operation can be performed by controlling the relative direction and distance between them.

More specifically, the illustrated drive device 1 is configured as a multi-degree-of-freedom drive mechanism.
Three arm rods 4 to 6 connected at joints 7 and 8
are configured to be rotatable around their axes, and the light source/sensor unit 2 fixed to the tip of the drive device 1 is configured to have five degrees of freedom (θ ₁ to θ ₅ ), thereby making it possible to freely control the relative direction and distance between the light source/sensor section 2 and the target surface 3. The degree of freedom of this drive device 1 is not limited to five.

The light source/sensor section 2 includes a light source 1 that irradiates light onto the target surface 3, as illustrated in FIG.
3, and a light receiving unit 1 that receives reflected light from the target surface 3.
4, and the light source 13 shown in the figure.
is three spot rays 15,
16, 17 are composed of three light emitting elements 18, 19, 20 that emit light from one point O in a diverging manner, and the light receiving section 14 emits three light spots A, B, B on the object surface 3. The reflected light from C is transferred to lens system 2.
1 so that the sensor 22 receives the light. This sensor 22 is constructed by, for example, arranging a large number of photoelectric elements in a matrix.
Any sensor may be used as long as it can detect the coordinate information of the image points A', B', and C' (see FIG. 3) of the three reflected lights projected onto the sensor 22.

Further, in place of the light source 13, a light source 25 as shown in FIG. 2b may be used. This light source 2
5 is three spot rays 26, 27, 28
Three light emitting elements 2 that emit light so as to be focused on point O
9, 30, and 31, and in this case, the object plane 3 can be placed at any position closer or farther than the O point.

Furthermore, in both cases of Figure 2 a and b above, one light emitting element is used instead of multiple light emitting elements, and the light from that one light emitting element is reflected by a mirror or prism. or by mechanically rotating one light projecting element and performing a detection operation when the light projecting element is located at three specific points. It is possible to adopt a configuration that obtains the following.

An arithmetic processing circuit and a drive control circuit are connected to the next stage of the light receiving section 14, and the arithmetic processing circuit performs arithmetic processing based on the coordinate information on the light receiving surface of the three spot light points obtained by the sensor 22. By doing this, the relative direction and distance between the sensor 22 and the target surface 3 are determined, and the drive control circuit compares the output of the arithmetic circuit with a predetermined reference value to match them. The driving device 1 outputs a signal for moving the light source/sensor unit 2 in the direction and position, and the driving device 1
is operated, and the light source/sensor unit 2 is configured to operate in a manner that follows the target surface 3.

Next, the contents of the calculation in the above-mentioned calculation processing circuit will be explained.

As shown in FIGS. 1 and 3, when three spot rays 15, 16, 17 are emitted from the light source,
These rays form three spot light points A, B, C on the object surface 3. Further, the reflected light from these spot light points is projected by the lens system 21 to form images at three imaging points A', B', and C' on the sensor 22.

In the sensor 22, the coordinate information (a', b', c') of these three image forming points A', B', C' is obtained, and the coordinate information is sent to the next stage arithmetic processing circuit. Sent.

The arithmetic processing circuit connected to the sensor 22 calculates the coordinates (a, b', c') of the spot light points A, B, C on the target surface 3 from the coordinate information (a', b', c').
b, c), and further calculate their coordinates (a, b,
c), the relative direction and distance between the light source/sensor unit 2 and the target surface 3 are calculated.

To explain this in detail in principle, in the above calculation circuit, three image points A', A', and
From the coordinates (a, b, c) of the three spot light points A, B, and C on the object surface 3 corresponding to B' and C', the direction p of the object surface 3 and the distance q from the origin 0 are found. .

That is, the direction vectors of the three spot rays 15 to 17 are u, v, w, and the equation of the photosensitive surface of the sensor 22 is ez・(x-f)=0 (where f is the perpendicular line drawn from the origin to the photosensitive surface. ), the vector representing the center position of the lens is l, and ez・l=-l- (ez is a unit vector in the Z-axis direction), then the sensor 22
From the coordinate information (a′, b′, c′) above, α ₂ = a′・ex/u′・ex, β ₂ = b′・ex/v′・ex γ ₂ = c′・ex/ w′・ex (where ex is a unit vector in the X-axis direction) is determined, and from this, a=αu=(ez・l)u/ez・[(lf)/α ₂ +u
] b=βv=(ez・l)v/ez・[(l−f)/β ₂ +v
] c=γw=(ez・l)w/ez・[(l−f)/γ ₂ +w
] is found.

Therefore, from these, p=q[v×w, w×u, u×v]/det(u, v, w
) 1/α 1/β 1/γ l=q/-P-, and the direction p and distance l of the target surface 3 with respect to the sensor 22 are determined.

The above explanation can be summarized as follows.

Device constants Vector representing the direction of beam A = (u _x , u _y ,
u _z ) Vector representing the direction of ^T beam B = (v _x , v _y ,
v _z ) ^Vector w = (w _x , w _y ,
w _z ) Distance between the center of the ^T lens and the origin of the sensor light-receiving surface - l
- Information to be measured Coordinates of spot A on the sensor light receiving surface (a _x ′, a _y ′)
Coordinates of ^T spot B on the sensor light receiving surface (b _x ′, b _y ′)
Coordinates of ^T spot C on the sensor light receiving surface (c _x ′, c _y ′)
^T calculation formula (underlined parts are constants) Unit normal vector of the object P=-p/-p- (1) Distance from the origin of the object surface l=-det[u, v, w]/-p - (2) However, p=(p _x , p _y , p _z ) ^T = 1/α×(vw)+1/β×(wu) +1/γ×(uv) (3) Note that is the cross product of vectors We show operations that can be calculated in advance.

Furthermore, det[u, v, w] represents the operation of the determinant when [u, v, w] is a 3×3 matrix, which can also be calculated in advance.

-p-= _x × _x + _y × _y + _z × _z (4) 1/α=u _z /-l-+u _x /a _x ′(-a _x ′-≧-a _y ′-
) =u _z /-l-+u _y /a _y ′ (-a _x ′-<-a _y ′-) ……(5) 1/β=v _z /-l-+v _x /b _x ′(-b _x ′-≧-b _y ′-
) =v _z /-l-+v _y /b _y ′ (-b _x ′-<-b _y ′-) ……(6) 1/γ=w _z /-l-+w _x /c _x ′(―c _x ′―≧―
c _y ′−) = w _z /−l−+w _x /c _y ′(−c _x ′−＜−c _y ′−) ……(7) The amount of calculation using the above formula is as follows. become that way. This makes it possible to perform calculations in the present invention very easily, and in a correspondingly short time.

Amount of operations (1) Assuming that p and -p- are fixed, the equation requires 3 divisions (2) The equation requires 1 division (3) The equation requires 9 multiplications and 6 additions (4 ) The formula has 3 multiplications, 2 additions, and 1 square root operation (5) The formula has 1 division and 1 addition (6) The formula has 1 division and 1 addition ( 7) The formula has 1 division and 1 addition, resulting in a total of 19 multiplications, 11 additions,
Only one square root operation is required.

Sensor 2 of the target surface 3 obtained in this way
The direction P and distance l with respect to 2 are transmitted to the next stage drive control circuit, where they are compared with predetermined direction and distance reference values P ₀ and l ₀ , and the light source/sensor unit is set in the direction and distance that match them. A signal for moving the drive device 2 is output, and the signal is transmitted to the drive device 1.

The drive device 1 is actuated by the above signal and operates as a light source.
The sensor section 2 is displaced, the direction and distance to the target surface 3 are corrected, and a tracing operation for the target surface 3 is performed.

To explain this in more detail, when the reference values P ₀ , l ₀ of the direction and distance of the light-receiving surface of the sensor 22 are given, the direction and distance P, l of the current target surface are measured, so this The amount of movement of the sensor 22 can be controlled from the information. In this case, the angle formed by the directions P and P ₀ and the axis of rotation are determined by the following equation.

W=P ₀ ×P Therefore, it is sufficient to rotate the sensor 22 by the angle W around the origin O. That is, it is sufficient to set the direction W/-W- as a rotation axis and rotate by an angle -W- around the axis.

Once the direction has been corrected in this way, then
The distance is corrected by translating the sensor 22 by Δl=l ₀ -l in the direction of P ₀ . As described above, the sensor 22 is corrected to the reference direction and distance with respect to the target surface 3, and a tracing operation is performed.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIGS. 2 a and b are configuration diagrams of different light source sensor sections,
FIG. 3 is an explanatory diagram showing the geometrical relationship between the light receiving surface of the sensor section and the target surface. DESCRIPTION OF SYMBOLS 1... Drive device, 3... Target surface, 13... Light source, 14... Light receiving part, 15, 16, 17, 26,
27, 28... Spot rays.

Claims (1)

[Scope of Claims] 1. A light source that emits three spot light beams onto a surface to be subjected to profiling control in a direction that diverges from one point or converges to one point, and reflected light from the three spot light points formed on the target surface. A light receiving section that receives the light through a lens system and detects the coordinate information of each light point on the target surface, and a relative direction between the light receiving section and the target surface based on the coordinate information output from the light receiving section. A non-contact curved surface tracing sensor, comprising: an arithmetic processing circuit for calculating distance and distance;