JPS5810482A - Device for inspecting difference at stage and inclination of measuring surface in robot - 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 The present invention relates to an apparatus for inspecting the level difference and inclination of a measuring surface in a robot.

In recent years, particularly in the field of manufacturing and processing, there has been an active development of industrial robots that can act autonomously and have, for example, human upper limb movement functions.

By the way, when such an industrial robot is used to assemble a part 2 by fitting it into a recess 1a of a part 1 as shown in FIG. After that, an inspection step is also necessary to check whether the component 2 has been correctly assembled into the recess 1a of the component 1.

If this inspection is successful, it is sufficient to inspect the level difference between the parts 1 and 2 in FIG. 1, or to inspect the inclination of the upper surface of the part 2.

As a method for performing this inspection, for example, the robot may be equipped with a visual function so that it can recognize the patterns of parts 1 and 2, and the state of the assembly of parts 20 to part 1 may be inspected based on the pattern recognition results. is possible.

However, with the above method, it is quite difficult to perform pattern recognition accurately, and it is not practical from a cost performance standpoint.

In view of the above points, it is an object of the present invention to provide a device for inspecting the level difference and inclination of a measurement surface in a robot, which is simple and has excellent cost performance.

To this end, the device for inspecting the level difference and inclination of a measurement surface in a robot according to the present invention is equipped with a movable part such as an arm or a mechanical hand, and the movable part of the robot that can control positioning is equipped with a small number of movable parts (all three) each having a returning habit. A displacement detection means having the above-mentioned stylus and outputting displacement data according to the displacement position of each of these stylus is provided, and when all the stylus of this displacement detection means is brought into contact with the measurement surface, The step and inclination of the measurement surface are inspected based on the displacement position data of the stylus and the position data of each stylus.

Embodiments of the present invention will be described below with reference to FIG. 2 and subsequent drawings.

First, with reference to FIGS. 2 and 3, an embodiment of the displacement detecting means provided at the tip of the arm of the robot will be described.

In Fig. 2, arm 3 constitutes the movable part of the robot.
The mechanical hand 4 attached to its tip can move within a predetermined coordinate space while its positioning is controlled by commands from a control unit of a robot (not shown).

The displacement detection means 5 integrally provided at the tip of arm B is
It has three stylus A, B, and C (the lengths of the protruding portions are equal) each having a returning habit and protruding parallel to each other from the arm surface 6a at intervals in a direction perpendicular to the arm surface 6a. , it is possible to output a displacement signal corresponding to the displacement position of each of these stylus A, B, C when it is pulled into the arm 6.

Detection of the displacement positions of the stylus A, B, and C by the displacement detection means 5 is performed as follows.

That is, as shown in FIG. 6, a spring 6 is inserted between the bottom of the guide hole 6b provided in the arm 6 and the stylus to give the stylus a return habit. When the stylus is displaced against the biasing force, the contact position of the movable contact piece 7 provided on the stylus with respect to the resistor 8 is changed.

Then, if one end of the resistor 8 is connected to the power supply Vc and the other end is connected to the ground, and the voltage between the movable contact piece 7 and the ground is taken out, the voltage can be adjusted according to the displacement position of the stylus. A displacement voltage signal can be obtained, thereby detecting the displacement position of the stylus.

Note that there are various methods for detecting the displacement position, such as a method using a differential transformer and a method using a Hall effect element, in addition to the method using the above-mentioned direct-acting potentiometer.

Next, an embodiment of the processing circuit for the displacement voltage signal of the displacement detecting means 5 is shown in FIG. 4, and this is shown in FIGS.
This will be explained with reference to the figures.

In FIG. 4, subtractor 9. 10. IN! , move the arm 6 shown in FIG. 2 to bring the stylus A, B, and C of the displacement detection means 5 into contact with, for example, positions al, bl, and C1 of the component 1.2 in FIG. 5, respectively. Each displacement voltage signal sA is output from the displacement detecting means 5 at the time.

It constitutes calculation means for calculating the difference between SB and Sc.

That is, the subtracter 9 calculates the difference between the displacement voltage signals sA and sB, the subtracter 10 calculates the difference between the displacement voltage signals Sn and sc, and the subtracter 11 calculates the difference between the displacement voltage signals sA and Sc. The calculation is performed when the signal PE is input. Note that the positioning completion signal PE indicates that the tips of the stylus A, B, and C are all at the position al of parts 1 and 2.

Displacement voltage signals SA and SB indicate that bl and cl have been contacted.
.

It is detected by a determination circuit (not shown) based on Sc and occurs when the drive of the arm 3 is stopped.

The absolute value circuits 12 to 14 take the absolute value of the difference signal "A-B z SB Cp "'A C from the subtracters 9 to 11.

In addition, the stylus A is at position a1, B is at bl, and C is at C! , the difference signals SA & 5B-Cs sAC are all positive (the greater the displacement stroke of the stylus, the greater the displacement voltage signal).

The subtracters 15 to 17 and the pass/fail judgment circuit 18 receive absolute difference signals 18A-nLISR-CI from the absolute value circuits 12 to 14.
, l5A-CI and a predetermined step reference signal Sr1~
A first inspection circuit for inspecting the level difference between components 1 and 2 is configured based on S[3.

Step reference signal Sr1. Sr3 is set according to the level difference between the positions a□, b□ and the positions al and C4 of the parts 1 and 2 when the assembly is normal, and the level difference reference signal Sr2 is set to zero. In addition, as shown in FIG. 5, when the stylus A is touched to al, B to bl, and C to C1, the subtractor 10. Absolute value circuit 16. Although the subtractor 16 and the subtractor 16 are not necessarily necessary, the subtractor 10°16 and the absolute value circuit 13 can be provided so that the inspection can be performed in the same way no matter where the stylus A, B, or C contacts. be.

The subtracter 15 calculates the difference between the absolute difference signal 1sA-Bl and the step reference signal Sr1, and the subtractor 16 calculates the difference between the absolute difference signal 1sA-Bl and the step reference signal Sr1.
The subtracter 17 calculates the difference between ISA-CI and Sr3.

The pass/fail judgment circuit 18 checks whether the subtraction results α, β, and γ from the subtractors 15 to 17 are all zero.

Therefore, the pass/fail determination circuit 18 determines that the assembly of parts 1 and 20 is normal by determining a-β-γ-0, and that the assembly of parts 1 and 20 is normal by determining that a-β-γ~0.
It is possible to inspect whether the assembly of item 2 is defective.

In addition, the pass/fail judgment circuit 18 does not strictly judge α-β=γ-〇, but determines that the parts 1 and 20 are assembled normally when they are within predetermined tolerance ranges such as δ1≦a, β, and γ≦δ2. It may be determined that.

Subtractor 19. The adders 20 and 21 and the inclination determination circuit 22 move the arm 6 shown in FIG. 2 to set the respective stylus A, B, and C of the displacement detection means 5 to the positions of, for example, parts 1 and 2 in FIG. 6, respectively. a
2. b2. When all contacts c2 are brought into contact, the displacement detection means 5
Each displacement voltage signal SA from .

Each stylus A is determined according to SB, Sc, and the current position data of the tip of arm B when arm 3 of the robot is stopped.
, B, C position data ao (r
aoy 31aot Zao)tbo("bot3'
bo, zbo).

Based on C0 (xCOy 3'CO)
It constitutes a second inspection means for inspecting the inclination of.

In this embodiment, the displacement voltage signals SA, SB, and Sc from the displacement detecting means 5 are not directly used, but the J subtracters 9 and 11 are used.
The difference signal 5A-By SAC is used.

In addition, position data at), bo, and CG of each stylus A, B, and C on the arm surface 6a of the arm 3 are the arm 60
The calculation is performed by a controller of the robot (not shown) based on current position data of the tip of arm B obtained from an internal sensor (for example, a potentiometer) provided at each welding part (not shown).

The subtracter 19 calculates the position data ao(raoy,!/ao9Zao>+
1) o('1)or'/bop zbo )t Co
Input ('Ccop ycot zCO) and send e=xa6 Zbosf='/2o from each output terminal E-J respectively.
3'1)or g=Zao-2l)or h=xa
o −xcOt i=−′/ao! /. OS J=
z30 Calculates and outputs a signal ZCO.

Signals e, f from output terminals E, F, Q of this subtracter 19
2g represents the vector boao=(e, 12g), the signals from the output terminals H, I, and J, and I and j represent the vector c(
1a6-(h, i, j). The plane determined by these two vectors boao, cr)C6 (FIG. 7) is the arm surface 3a of the arm 3 and does not represent the upper surface of the component 2.

Therefore, the adder 20 adds the signal g output from the output terminal G of the subtracter 19 and the difference signal 5A-B output from the subtracter 9 to obtain the signal k, or the adder 21 adds the signal g output from the subtracter 19 The signal J output from the output terminal J of , and the difference signal 8A-C output from the subtracter 11 are added to obtain the signal l, respectively.

In this way, the vector b2a2=(e, f, k) determined by the signals e, f, and k, and the signal i.

Vector C2az=()l, j, determined by l
The plane S (Fig. 7) determined by
B.

It represents the plane connecting the ends of C, that is, the top surface of the component 2.

The slope determination circuit 22 calculates the vector b2a2. The plane S determined by c2a2 (ptx+qly+rtz+s
t-o) and, for example, the bottom surface (1) 2 of the recess 1a of the component 1
．． r+q2y+r2z+52=0), where θ is the angle formed by the above two planes, and the result of the calculation is cosθ−1, that is, it is checked whether it is θ−0 or not, and if θ−〇, Part 1,
20 If the assembly is normal or θ~0, parts 1 and 2
0 assembly is determined to be defective.

In the above embodiment, an example has been described in which the inspection is performed to determine whether the assembly of two parts is successful or not. However, for example, the inclination determination circuit 22 shown in FIG. For example, it is possible to simply check how much the part is tilted.

Further, in the above embodiment, an example was described in which the displacement detection means 5 was provided at the tip of the arm B of the robot, but it may also be provided on the mechanical hand 4.

As explained above, the device for inspecting the level difference and inclination of the measuring surface of a robot according to the present invention has a simple configuration and can accurately inspect the level difference and inclination of the measuring surface, so it is advantageous from the point of view of cost performance. If so, it is highly preferred.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of how parts are assembled to explain the background of the invention, and Fig. 2 shows a robot arm equipped with displacement detection means according to the invention and a mechanical hand attached to its tip. , FIG. 6 is an explanatory diagram of the detection principle of the displacement detection means in FIG. 2, FIG. 4 is a block diagram showing an embodiment of the signal processing circuit of the present invention, and FIGS. 5 and 6 7 is a perspective view for explaining the contact position of each stylus of the displacement detecting means with respect to the component, and FIG. 7 is a coordinate diagram for explaining the operation of FIG. 4. 1.2... Part 1a... Concavity 6
...Arm 4...Mechanical hand 5...Displacement detection means A, B, C
...Stylus 9-11, 15-17, 19...
...Subtractor 18 ... Pass/fail judgment circuit 2
0, 21...Adder 22...Inclination judgment circuit 1II Figure 3 3m

Claims (1)

[Claims] In a robot equipped with a movable part such as an arm or a mechanical hand, and capable of controlling the positioning of the movable part, at least three or more stylus provided on the movable part each having a return habit are sounded, and these a displacement detecting means that outputs displacement data according to the displacement position of each stylus; and a displacement detecting means that outputs displacement data according to the displacement position of each stylus, and the displacement detecting means when all of the stylus of the displacement detecting means are brought into contact with the measurement surface by driving the movable part of the robot. a first inspection for inspecting the level difference on the measurement surface based on each calculated data from the calculating means and predetermined level difference reference data; and the displacement detection means determined according to each displacement data outputted from the displacement detection means when all the stylus of the displacement detection means are brought into contact with the measurement surface, and the current position data of the movable part of the robot. and second inspection means for inspecting the inclination of the measurement surface based on the position data of each stylus.