JPS60161085A - Extractor for part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a parts picking/unloading device 17 for picking up parts one by one from a pile of parts and supplying the parts to a cutting station such as an assembly station. be.

[Prior art]

Conventionally, a vibrating component feeding device that matches the shape of the component has been used as a device for picking up parts placed in a loose state where the position and orientation are not fixed one by one and feeding them to a predetermined position. However, this vibrating type parts feeding device is not versatile and cannot be adapted to changes in part shape, and because it is a vibrating type, it cannot handle large parts.

Not only is this method unsuitable for parts that are easily damaged, but it also has drawbacks such as the generation of noise.

[Summary of the invention]

The present invention has been made with the aim of improving such drawbacks, and includes a hand having a pair of fingers each having a three-way force detector and a gripping part, a driving part that does not move these fingers facing each other, and the position and posture of this hand. A component that can detect the direction of the reaction force that occurs when the tip of a finger touches one of the bulk parts and extract the part according to the position and orientation of the part in contact. This provides a slow ejection device.

[Embodiments of the invention] FIG. 1 is a schematic diagram showing an embodiment of the present invention.

In Figure ζ, +11 is a hand, (2) is a hand (1)
A positioning device such as a robot arm that changes the position and attitude of the robot, +31 is the part to be taken out, and (4) is the box in which the part (6) is placed.

The x, y, z coordinate system shown in one box and one figure is hand (1
The gripping direction of hand (1) is YX axis, and the upper and lower Y directions of hand (1)
The Z-axis is an axis perpendicular to the X-axis and the ry-axis, and the x, y, and z seat systems shown in subsequent figures are also similar to this.

The hand (17 is not shown in Figure 2) has a pair of fingers (5a
5b] and fingers (5a) and (5b). A pair of fingers (5a), (5b
) are gripping parts (7a), (7b) and gripping J'4 part (
7a) s (7b) A positive force detector (8) with a protruding tip
a) and (8b), the gripping tuning fork 7a) and the three-way force detector (8a) are fixed to the finger support part (17a), and the gripping part (7b) and the three-way force detector (8b) are fixed to the finger support part. (17b
) is fixed.

FIG. 6 shows the configuration of the three-way force detector (8a) described above.

In the figure, (9a) is a detection base, (10a) is a leaf spring fixed at both ends to the detection base (9a), and (Ila) is a plate spring fixed at both ends to the detection base (9a).
is an elastic body that is fixed to the center of the leaf spring (10a) and has two thin portions in each of the X and X directions.

Two strain gauges (12 m) are attached to the leaf spring (10a) symmetrically in the center, and two rabbit gauges (13a) are attached to the elastic body (Ila) in the thinner part in the X direction. Two strain gauges (14a) are pasted on each of the parts that are pasted and become thinner in the X direction. The leaf spring (10a) and the elastic body (Ila) are pasted with gauges (12a) to (14a) as described above, as described below.
By connecting the strain gauges (12a) to (14a) to the Y bridge circuit, the two-directional component of the force acting on the tip of the finger (5a), that is, the three-way force detector (8a) caJ, is connected to the strain gauge. (12a), X-direction component strain gauge (
1'3a), y-direction component strain gauge (14a) has 1 independent detection. The three-way force detector (8b) on the other hand is also implanted in exactly the same manner as above.

FIG. 4 shows the construction of the drive section (6). In the figure (
15) is the base, (16a), (16b) is the base (1
Of 5), a pair of slide units (17aL (17b) and G!) are mounted facing each other with slide units (16a).

A finger support fixed to the movable surface of (16b), (19)l
It is a rotation tl' having a right-hand thread (39a) and a left-hand thread (39b).

(18aL (18b) are right-handed screws (39a) of the rotating shaft (19), respectively.

is incorporated into the left-hand screw (39b), and the finger support sound L (
17a) A nut fixed to m (17b), (21) a motor that drives a rotating shaft (19) fixed to a base (15), (20) a shaft of the motor (21) and a rotating shaft (19) fixed to the base (15);
Figure 5 shows the control device. The control device (22) includes a positive force detection circuit (26) that processes output signals from the three-way force detectors (8a) (8b), and a positioning device control circuit (24) that controls the positioning device (2). ), a hand control circuit (25) that controls the motor (21) of the hand (1),
It consists of a microcomputer (26).

Positive component force detection circuit (23) GE strain gauge (12a) ~ (1
4b), each strain gauge output signal processing circuit (27
) ~ (52) Be prepared. For example, the processing circuit (27
), two strain gauges (12a) and two fixed resistors (6
The bridge circuit composed of 6) is a strain amplifier (6).
4), the output signal of this bridge is amplified by a strain amplifier (64) and output as a DC signal. Other strain gauge output signal processing circuits (28) to (
32) similarly outputs a DC signal. However, the bridge circuit in the strain gauge output signal processing circuits (27) and (30) extracts only the forces in two directions that act on the leaf springs (10a) and (10b) to which the strain gauges (12aH12b) are attached. For this reason, the strain gauges (12a) and (12b) are not facing each other, but are arranged in a 6-way configuration, and the bridges in the strain gauge output signal processing circuits (28), (29), (31), and (32) are connected. The circuit uses a strain gauge (13a) to extract the force in the XIy direction acting on the elastic bodies (11a) (11b).
), (13b), (14a), L14b) 2 each
414 pieces are configured so that the number of pieces is MW. The IU flow multiplier signals from the strain gauge output signal processing circuits (27) to (62) are each input to the sample hold circuit (66) via the multiplexer (35)Y, and converted into digital No. 41 by the A/D conversion circuit WW9). Taryo, Microcomputer (26
) The positioning device control circuit (24) consists of a plurality of actuator drive circuits that move the actuator vm of each axis of the positioning device (2) that changes the position and posture of the hand (1), and is implemented by a microcomputer. (26) and drives the actuator in accordance with the Runij command.

The hand control φJ circuit (N5) is connected to the hand (1) motor (
21]f-q This is a circuit that is driven according to commands output from the microcomputer (26).

The operation of the component extraction device configured as described above will be explained using a cylindrical component as an example. First, in order to understand the basic operations, we will explain the operation of taking out several cylindrical parts that are not tilted with respect to the -x and y planes.

First, in Fig. 6, the positive component force gK of fingers (5a) and (5b) is detected.
8a).

(8b) and the cylindrical part (68), and the relationship between the posture and position of the cylindrical part (68). ,
7. In the Z coordinate, the three-way force detector (8a) when the hand (1) is brought into contact with the cylindrical part (68) from above the shaft 2.
, (8b) and the cylindrical part (68), the axis of the cylindrical part (68) is inclined at an angle θ2 with respect to the y-axis), and the axis of the cylindrical part (68) is tilted at an angle θ2 with respect to the y-axis). A case is shown in which the angle between the two axes and a straight line connecting the melting point and the axis on two planes is 01. 8r! Figure 6 (BL and IC
l is the operating state of force in the contact state of (a) at angle θ1
The case where is larger than the friction angle θf↓ is shown. Three-way force detector (8a) I in contact with cylindrical part (68)
c is the resultant force F of the reaction force N in the normal direction at the contact point and the friction force μ peak 1 acting on it, and the force Fx in the x, y, and z directions detected by the three-way force detector (8a), Fy and F'z are given by the following equations.

Here, μ is the three-way force detector (8a) and the cylindrical part (68)
I′J<friction coefficient between tS friction angle θf and Jf!
p; A coefficient μG m μ knee θfQ). Therefore, the positive force detection f5 (8a) f is the acting force Fx, F
Angle θ1. from y, E;'z. θ2b - Obtained by the following equation.

However, the above equation only holds true if the angle θl is Ji, 'Q friction angle θf↓υthick (·, 1).

Once the angle θ1 is determined, the position 1δ of the contact point at the XLz seats A and V with the axis of the cylindrical component (38) as the origin can be determined by the following equation, where γ is the diameter of the cylindrical component (68).

1. If the angle θ1 is less than M'4 friction angle θf, then
There is no effect in the Y direction, Fx , F”y , F”z
is given by the following equation.

Therefore, the forces Fx, F acting on the three-way force detector (8a)
y.

The angle θbθ2 cannot be obtained from Fz.

Next, the operation of taking out F parts into the above-mentioned parts taking out device will be explained.

Position the L cup 17 and f11 on the positioning device (2+) at an arbitrary position above the area of the box (4) in a state perpendicular to the xy plane.Next, place the finger at a distance shorter than the diameter of the cylinder part (68). After setting the interval of (5a), L5b), the output X al' from the three-way force detector (8a), (8b)
While monitoring lam Z a # X b mybIzb with the microcomputer (26),
η is lowered by the positioning device (2).

Either finger (5a) or (5b) is a cylindrical part (lo 8
), and the outputs xa, ya, za, xb from the three-way force detectors (8a), (8b).

It is assumed that when either yb or zb reaches a predetermined value or more, the hand (11) stops descending. fc, for example, J Mouse Qi, comes into contact with the cylindrical part (68). If the forces in the X and Y directions acting on the finger (5a) are both zero, the finger (5a)
) Hand (1) rises until the tip of the box is outside the box +41.

In the distance, the radius γ of the cylindrical part (68), the radius γ of the cylindrical part (6B)
) and J, h' of finger (5a), if the angle is θf, then 2
Any direction on the xy plane by rainθf -\Hand (1
), lower the hand (1), and make contact at 1δ until the force in either the X or X direction does not become zero.

The force acting on the finger (5a) in either the X or X direction is zero'
If not, the formula for the former self (2 + (31 to cylindrical part (3
8) Place 11 [and the posture of the microcomputer (26)
Calculate the position and posture of the bale and cylindrical part (68) that the hand (1) has placed until the tip of the finger (5a) comes out of the box (4).

Hand in the xy plane (11th place d and posture n cylinder song U1
Apply oil to the L seams that are attached to the parts. Next, the cylindrical part (6
8) diameter F is large, and while grasping the cylindrical part (68), open the fingers on the box, lower the hand (1), correct the position in two directions, and close the fingers (5a, L5b). Move. The gripping parts (7aH7b) ↓ of the fingers (5a) (5b) ↓ protruding positive force detection'& (8a) L8b) are bent,
The fingers (5a) and (5b) Y are closed until the cylindrical component (68) comes alongside the gripping portions (7a and 7b) to complete the gripping operation.

Next, the cylindrical part (38) is held and handled by the positioning device (2) to a predetermined position. If the X-direction outputs xa and xb of the component force detectors (8a) and (8b) during handling are almost zero, it is assumed that there is a gripping error or that the cylindrical part (38) has fallen during the handling operation. Again, make the initial contact motion a little less.

Perform the above operation next time to create a cylindrical part (38)Y.
Next, we will explain the operation of taking out cylindrical parts placed in a box in an arbitrary posture during the three-missing element.

Since the grasping motion, handling motion, etc. are almost the same as the above-mentioned motions, the method for obtaining the axial direction of the contact motion cylindrical part (68) and the position of the contact point will be explained with emphasis on the hand (17'r box (4) ], the fingers (5a), (5b) come into contact with any of the plurality of cylindrical parts (68).

Assuming that the finger (5a) touches the cylindrical part (68), 1
ti5a) and the cylindrical part (68) first come into contact with each other when the finger (5a) contacts the curved surface of the cylindrical part (68).

There are two situations when the finger (5a) contacts the plane of the cylindrical part (68). Distinguishing between these two states can be done by making the first (near the melting point) contact with the finger (5a). In other words, the direction of the force applied in the first welding operation and the direction of the force in the second welding operation can be distinguished. If the direction of the force obtained in the first contact motion is the same, it is in contact with a flat surface, and if the direction of the force obtained in the first and second contact motion is different, it is in contact with a curved surface. First, when the finger (5a) comes into contact with the curved surface of the cylindrical part (68), x, y,
Figure 7 (al, (
I will explain in bl. If the axial unit vector of the cylindrical part (68) is the normal vector at the first and second contact points of the finger (5a), then the axial unit vector b of the cylindrical part (68) and the normal at the contact point are Since the line vector alsa2 is orthogonal, the following equation is obtained.

Also, beans can be expressed as a unit vector, so the x, y, and z components of b
x, by, and bz are given by the following equations.

However, formula (8) is alz=(l, a2z=Oe a2z 11aty
4axZ 011+Y J (Sets if all 91 do not hold.

On the other hand, the force acting on the finger (58) when the finger (58) is brought into contact with the point of the normal vector alta2 from two directions is given by the following equation when the finger (58) is in contact with the point of the normal vector a1.

From the above formula, the angle α1. It is obtained by βd quadratic equation.

Each component of the normal vector al has an angle α1. Since it is expressed using βIY, the normal vector of the contact point can be obtained from the force acting on the finger (5a). Therefore, from the force obtained by two contact operations, equations (8), (it), (12) '(1
′, the axial unit vector of the cylindrical part (68) is
By the way, vector H, which is on a plane that intersects vector b and two axes t and is perpendicular to vector 100, is given by the following equation.

The normal vector xl at the contact point is a vector; the vector b
The vector a1 can be expressed by the following equation.

The angle θ is obtained by comparing the components of the vectors in equations (12) and (14) above. Therefore, the direction of vector 100 is 7 axes, the direction of vector H is '&z'fll+, vector π
and taking the 7 axes in the direction perpendicular to the vector C, 7CX', y
The position of the contact point in ', z' coordinates is given by.

When the finger (5a) comes into contact with the cylindrical part (68), the normal vector obtained from the force acting on the finger (5a) is the axial vector of the cylindrical part (38).
The posture of the cylindrical part (68) can be seen. Next, the force method (it) L12λ obtained by contacting the curved surface part
(14), (15) 'Y using x', y', z'
The position of the contact point in the coordinate system can be obtained.

In addition, in the contact operation, when the angle α1 is less than the friction angle θf and the forces Fx and Fy acting on the finger (5a) are both zero, Rurui is until the conditions of are no longer satisfied.
i1! Change the position and detect the request.

Next, based on the posture of the cylindrical part (hu) obtained by the above-mentioned contact operation and the contact position in the x', y', z' coordinate system, first, the hand (111 yen: x, y, z coordinate system is x
Hand (1) to match the ',y',z' coordinate system
The posture of is changed using the positioning device fl(2), and further x', y
From the position of the contact point obtained in the ', z' coordinate system, the position of the hand [1] is corrected by the positioning device u (21) so that the hand (1) can grip the curved part of the cylindrical part (68). , grip and handle.

In the embodiment described above, the finger support part (17a) m (
17b) with grip fA (7a), (7b) and three-way force detection Ha (8a), (8b)' fixed, but one grip part (7a), (7b) or three-way force detector (8
a) or (8b) is moved to the finger support portion (17aL) via at least one shaft moving mechanism having an actuator.
(17b), and when the component (31 to 0) is in contact, the positive force generators (8a) and (8b) are relatively connected to the grip part (7).
a), (7b) Protrude in the L direction, and during gripping operation, the gripping parts (7a) (7b) Y positive component force detectors (8a) (8b)
By protruding, the three-way force detectors (8a) and (8b
) k It may be configured to protect against overload.

Furthermore, in the above embodiment, the gripping parts (7a), (7b) and the three-way force detectors (8a), (8b) were arranged in Y parallel, but as shown in FIG. L17b
) are fixed to the three-way force detectors (8a), (8b), and the gripping parts (7a), L are fixed to the three-way force detectors (8a), (8b).
7b) 'lzt: fixed, three-way force detector (8a),
(8b) and the gripping portions (7a) and (7b) can be arranged in series to produce the same effect.

Further, in the embodiment described above, a cylindrical component was explained as an example, but according to the present invention, a three-way force detector (8a) is used.

In accordance with the output from (8b), the position and orientation of the hand (1) is changed appropriately according to the position and orientation of the part, and before finally grasping the part, only the gripping direction, that is, the X direction is used. In order to avoid obtaining a stable gripping state in which the force exerted on the fingers (5a) and L5b), the part can be taken out by changing the position and posture of the hand (1). A wide range of applications are possible without being limited to.

〔Effect of the invention〕

The present invention has been explained above and has the following points: When the tip of 'r7 comes into contact with a part, the position and orientation of the part is detected by adjusting the state of the force acting on the finger, and the position and orientation of the part is detected. The configuration is such that parts can be taken out according to the user's posture and posture, which has the effect of increasing the versatility of parts taking out.

Also, since there is no driving part, there is no noise.
J, l; has the effect of contributing to the improvement of the i environment.

[Brief explanation of drawings]

Fig. 241 is a schematic hit diagram showing an embodiment of this invention, Fig. 2 is a perspective view showing a hand according to an embodiment of this invention, and Fig. 6 is a perspective view showing a three-way force detector of the hand shown in Fig. 2. figure,
FIG. 4 is a plan view showing the driving part of the hand shown in FIG. 2;
FIG. 5 is a block diagram of a control device according to an embodiment of the present invention, FIGS. 6(a), (bl, and , ibl &′
FIG. 8 is a perspective view showing another embodiment of the present invention. (・1)...Hand, +21...Positioning device, [
31... Part, (4)-phase, (5a), (5b) ・
-・Finger, +61-・Drive unit, (7a), (7b)・・
・Gripping part, L8a), (8b)...Three-way force detector, (
22)...control device. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Patent Attorney Sanro Kimura Figure 1 Figure 4 Figure 5 Figure 2 m6 Figure 7 Figure 8 (b) Display of matter fl Tokken Sho 59-134! No. 10 2,
Name of the invention Parts extraction device 3, Person making the amendment 4, Agent 6, Contents of the amendment (1) Amend "operator" in line 4 of the specification to "move", (2) ``Axis ZJ'' in line 8 of Specification @ 8th Tei is corrected to ``2 axes.'' (3) ``Entertainment'' in line 16 of page 11 of the specification is corrected to ``grasping.'' (4) Page 4, line 7 of the specification (5) Line 5 from the bottom of the 15th shell of the specification: “From force, formula (8
), αυ, 02'' from the 12 normal vectors using equation (6)
”, (6) Ia+J in lines 6 to 7 of the 16th line of the 16th line! 'f
rc1a1”. (7) ``Formula (b) above'' on page 116, line 8 of the specification
)”

Claims (1)

[Scope of Claims] 1. A device for picking out a part 1i]^ from a plurality of parts stacked in bulk, comprising a pair of fingers each having a three-way force detector and a gripping part, and the fingers facing each other. A hand having a drive unit for operating the hand, a positioning device that changes the position and orientation of the hand, and a control f[1 positioning device that processes the output from the three-way force detector to control the hand and the positioning device. , detecting the position and orientation of the part based on the state of the force acting on the finger when the tapered end of the finger comes into contact with the part, and extracting the part according to the position and orientation of the part from the detection results. A parts counting device featuring: 2. The parts counting device according to claim 1, characterized in that the three-way force detector in the hand and the gripping portion are arranged in parallel. 6. A special H'F claim characterized in that the three-way force detector protrudes in the direction in which the gripping part ↓ fingers move oppositely and in the direction of the tip, and the tip of the three-way force detector is the tip of the finger. The parts removal device according to scope 2. 4. The device for determining the number of parts p according to claim 1, characterized in that a three-way force detector provided in the hand and a gripping portion are arranged in series.