JPH07241733A - Automatic part assembling method and automatic part assembling device - Google Patents

Abstract

PURPOSE:To provide an automatic part assembling method and a device therefor enabling the assembling of parts that cannot be assembled unless the axes and phase are aligned. CONSTITUTION:Parts pressing force is exerted on a compliance mechanism (RCC) 11, and this force is measured by a force sensor 10 to compute the axis deviation direction and quantity. Using this computed information, a robot 8 gripping parts and positioning mechanism are relatively moved to perform alignment. In the case of failing to align at a time, the parts pressing force is once released to perform alignment again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic component assembling method and an automatic component assembling apparatus for automatically fitting and inserting a component that requires shaft centering and phase matching.

[0002]

27 to 33 are views showing a conventional parts automatic assembly apparatus, FIG. 27 is a front view showing the basic construction of the parts automatic assembly apparatus, FIG. 28 is a partially enlarged view of FIG.
29 is a perspective view showing an assembly target component, FIG. 30 is a sectional view showing the assembly target component and its positioning or component supply, FIG. 31 is a front view for explaining the operation of the conventional automatic component assembly apparatus, and FIG. FIG. 33 is a plan view showing the assembled state of the parts to be assembled.

In FIG. 27, 7 is a chuck mechanism for holding a component, 8 is horizontal movement along horizontal orthogonal axes X and Y, which is generally called a SCARA type robot, vertical movement along vertical axis Z, and vertical axis. Horizontal wrist rotation θ about Z 4
A robot 9 having a degree of freedom is a connecting mechanism for connecting the chuck mechanism 7 to the wrist tip (that is, the work implement attaching portion) 8a of the robot 8.

As shown in FIG. 28, the connecting mechanism 9 has an RCC (REMOTE CENTER COMPLIA) for absorbing a minute axial center and an angular deviation of a component to be assembled.
NCE) 11 and Z-axis compliance mechanism 12.

The above Z-axis compliance mechanism 1
2 is a plate 16 attached to the tip 8a of the wrist of the robot 8
A plate 17 attached to the RCC 11, a guide 13 for allowing the plate 17 to slide relative to the plate 16 only in the Z-axis direction (vertical direction) of the robot 8, the plate 16 and the plate 17
The compression coil spring 14 provided between the compression coil spring 14 and the proximity switch 15 that detects the approach of the detection member 15a when the deflection amount of the compression coil spring 14 exceeds a predetermined value and turns on the output signal. It is composed of a load sensor 18 for measuring the force in the insertion direction. Here, guide 1
3, the compression coil spring 14, the plate 16, and the plate 17 constitute a float mechanism that floats the chuck mechanism 7 in the direction opposite to the component insertion direction.

In FIG. 29, reference numeral 1 denotes a hole portion 1a with a key.
2 is a second part having a keyed shaft part 2a into which the keyed hole part 1a is fitted.
In FIG. 30, 3 is a positioning mechanism for positioning and holding the first component 1, and 4 is a component supply mechanism for feeding the second component 2 to the apparatus.

The robot 8 is automatically controlled by a controller (not shown), for example, by a teaching cheek back type, and the first part 1 is attached to the shaft portion 2a of the second part 2.
The work of fitting the hole portion 1a is performed. When the output of the proximity switch 15 is turned on, the robot 8
The operation program of the controller is set so as to make an emergency stop.

Next, the operation will be described. First, the robot 8 moves and the chuck mechanism 7 holds the second component 2 supplied by the component supply mechanism 4. Then, the robot 8 is moved to position the second component 2 above the first component 1 positioned by the positioning mechanism 3 as shown in FIG. 31, and then descends to be fitted into the first component 1. Let

At this time, when the axis and the phase are accurately adjusted by using a means such as a CCD camera (not shown) in advance, the shaft portion 2a of the second component 2 is a hole portion of the first component 1. 1a is entered and smooth fitting is realized.

However, when the axis and the phase are not accurately aligned in advance or it is difficult to align them accurately, in the process of lowering the second component 2, the second component 2 is usually replaced with the first component 1. On the other hand, since the axis is slightly off,
First, the chamfered portion at the lower end of the shaft portion 2a of the second component 2 contacts the upper end of the hole portion 1a of the first component 1. Therefore, as shown in FIG. 32, the force F acts on the second component 2 in the arrow direction. This force F causes the RCC1 to deform and passively absorb the axial misalignment.

Even if the axes of the second component 2 and the first component 1 are aligned as described above, the phases are usually slightly out of phase, so the wrist tip 8a of the robot 8 is rotated around the θ axis. To match the phase. That is, the wrist tip 8a of the robot 8 is slowly rotated around the θ axis, and the robot 8 is stopped at a position where the value of the load sensor 18 becomes a certain value or less. In this state, if the second component 2 is pressed against the first component 1, the fitting is smoothly realized unless the components 1 and 2 are twisted.

The second component 2 and the first component are provided by the RCC 11.
After aligning the axes of the parts 1 of
Even if a is rotated about the θ axis and the phases are adjusted, if the rotation axis of the wrist tip 8a of the robot 8 and the rotation axis of the second component 2 moved by the RCC 11 are significantly deviated, the second component 2 is inclined by the amount of the clearance with the first component 1 and becomes a so-called twisted state, and smooth fitting cannot be performed even if the RCC 11 is flexible, or in the worst case, the fitting is impossible. When the fitting becomes impossible, the chuck mechanism 7 does not follow the lowering of the wrist tip 8a of the robot 8, so that the compression coil spring 14 contracts and the plates 16 and 17 move toward each other. As a result, the robot is prevented from being overloaded, and finally the proximity switch 1
5 is turned on, and the robot 8 receives the ON signal of the proximity switch 15 and makes an emergency stop.

Further, even when the axis and the phase are measured and fitted by using a means such as a CCD camera in advance, the fitting cannot be done when the measurement is difficult due to the shape of the parts.

Further, in the case of inserting a rectangular part having a chamfered portion, in the case where the RCC 11 aligns the shaft center and rotates the wrist tip 8a of the robot 8 around the θ axis to align the phase, the direction in which the phase shift can be eliminated is Since there is only one direction,
If the direction cannot be determined, the fitting cannot be done.
The reason will be described with reference to FIG.

In FIG. 33, 5 is a first part having a hole 5a having a square chamfer, and 6 is a second part having a square shaft 6a. Chuck mechanism 7 of robot 8
Is trying to fit the shaft part 6a of the second part 6 into the hole 5a of the first part 5 by gripping the second part 6, as shown in FIG. Rotate to match the phase. However, when trying to rotate the second part 6 in the direction B, the second part 6 is moved along the square chamfered part of the first part 5.
The component 6 moves in the direction opposite to the fitting insertion direction. Therefore, in order to eliminate the phase shift in this way,
It is necessary to rotate the second part 6 in the direction A.

[0016]

Since the conventional automatic parts assembling method and parts automatic assembling apparatus are configured as described above, the second part is fitted to the first part by aligning the shaft center and the phase. For insertion, the axis and the phase are measured in advance by using a means such as a CCD camera, or the axes of the second component 2 and the first component 1 are aligned by RCC, and the wrist tip 8a of the robot 8 is inserted. It is necessary to match the phase by rotating the axis around the θ axis.

However, in reality, even if a means such as a CCD camera is used, it may be difficult to detect the axial center and the phase depending on the shape of the parts, which makes automatic parts assembly uncertain.
Alternatively, when the axes of the second component 2 and the first component 1 are aligned by RCC and the tip of the wrist 8a of the robot 8 is rotated around the θ axis to align the phases, the robot 8
When the rotation axis of the wrist tip 8a of the above and the rotation axis of the second component 2 moved by the RCC are largely deviated, the second component is tilted by an amount corresponding to the clearance with the first component and becomes a prying state, There was a problem that automatic parts assembly became impossible.

Further, in the conventional automatic component assembling apparatus, when the wrist tip 8a of the robot 8 is rotated around the θ axis to match the phases, the robot has no means for detecting the moment around the θ axis. When the parts are twisted, the chuck mechanism 7 does not follow the rotation of the wrist tip 8a of the robot 8 around the θ axis, and there is a problem that the robot is destroyed in the RCC or in the worst case.

Further, the conventional automatic component assembly apparatus does not have a function of detecting the direction of phase matching when the phase of a rectangular component having a chamfer is matched by rotating the wrist tip 8a of the robot 8 around the θ axis. It was

It is an object of the present invention to provide an automatic component assembling method capable of surely performing automatic assembly by aligning the axis and phase of a component.

It is an object of the present invention to provide a component automatic assembly apparatus capable of surely and smoothly performing automatic assembly by aligning the shaft center and phase of a component.

[0022]

According to another aspect of the present invention, there is provided a method for automatically assembling a component, wherein a second component is pressed against a positioned first component from an assembling direction, and the second component is a first component. The moving direction and the moving amount of the second component necessary for making the component force orthogonal to the assembly direction received from the second component almost zero are calculated, and the second component is moved in the moving direction to generate the component force. Is set to be substantially zero, and the pressing force in the assembling direction is moved to be smaller than a predetermined value, and then the second component is moved in the assembling direction with respect to the first component.

According to a second aspect of the present invention, there is provided an automatic component assembling method in which the second component is pressed against the first component and then separated, and after the axial alignment, the second component is again pressed against the first component. This is to repeatedly perform what is done.

According to a third aspect of the invention, there is provided an automatic component assembling method, in which after the second component and the first component are aligned with each other,
The second component is operated by calculating the rotation direction and the rotation amount necessary to make the moment reaction force around the assembly direction axis received by the second component from the first component to be substantially zero, and rotating the second component by the rotation amount. .

According to the fourth aspect of the present invention, the component automatic assembly method determines the direction in which the phase of the second component is changed as a function of the moment reaction force about the assembly direction axis.

According to a fifth aspect of the present invention, there is provided an automatic component assembling method, wherein when the moment reaction force about the assembling direction axis becomes larger than a predetermined value during the phase alignment of the second component and the first component, The phase matching process is immediately stopped.

According to a sixth aspect of the present invention, there is provided an automatic component assembling apparatus provided with a robot and a positioning mechanism which relatively move in X, Y and Z axis directions orthogonal to each other and in a θ axis direction which rotates about the Z axis. A compliance mechanism and a four-axis force sensor are provided on either one of them, a pressing step of pressing the second component against the first component, a calculation step of calculating an error correction amount, and the second amount of the error correction amount. The controller includes a controller that sequentially executes an axis aligning step of moving the part, a phase aligning step of rotating the second part, and an inserting step of moving the second part in the assembling direction with respect to the first part. .

According to a seventh aspect of the invention, the controller automatically presses the second component against the first component and then separates the second component, and after aligning the second component, the second component is again assembled into the first component. It has a function of repeatedly pressing a part.

In the component automatic assembly apparatus according to the eighth aspect of the present invention, the force M measured by the four-axis force sensor after the controller aligns the second component with the first component
It has a function of calculating the correction amount Δθ of the error due to the overshoot in the rotation direction around the θ axis as a function of z, and executing the rotating step of rotating the θ axis by this Δθ.

According to a ninth aspect of the invention, the controller automatically determines the rotation direction around the θ axis as a function of the force Mz in the Z axis direction measured by the four-axis force sensor. It has a function.

According to a tenth aspect of the present invention, in the component automatic assembly apparatus, when the controller adjusts the phase of the second component to the first component, the moment about the θ axis becomes larger than a predetermined value, It has a function of immediately stopping the rotation around the θ axis.

[0032]

According to the first aspect of the present invention, the second component is pressed against the first component with a predetermined force in the fitting insertion direction, and the second component receives the fitting from the first component. By measuring the movement direction and movement amount of the robot necessary to make the component force in the direction orthogonal to the insertion direction almost zero,
There is no need to match the axis and phase in advance, and automatic assembly can be performed reliably and smoothly.

According to the second aspect of the invention, the component automatic assembly method presses the second component against the first component to calculate the amount of axis deviation, and then pulls the second component from the first component. After separating and moving in the axial alignment direction, pressing the second component again against the first component is repeated, so that the component is not damaged, and even if the axial alignment cannot be performed by only one pressing, it can be performed reliably and smoothly. Automatic assembly is possible.

According to the third aspect of the invention, the second component is automatically assembled by moving the second component so that the moment reaction force about the axis in the assembly direction received from the first component becomes substantially zero. It is possible to prevent the component from being tilted by the amount of the clearance from the first component and being in a twisted state and being unable to be fitted.

According to a fourth aspect of the present invention, there is provided a method for automatically assembling a component, wherein the second component changes a phase of the second component as a function of a moment reaction force around the axis in the assembling direction received from the first component. By determining, it is possible to surely perform automatic assembly.

In the method for automatically assembling parts according to the fifth aspect of the invention, when the moment reaction force around the axis in the assembling direction becomes large during the phase alignment of the second part and the first part, the phase alignment is immediately performed. Stopping does not damage the parts.

In the four-axis force sensor according to the sixth aspect of the present invention, the moving direction necessary for making the component force in the direction orthogonal to the fitting insertion direction received by the second component from the first component substantially zero. And the amount of movement is measured, the controller
By moving the moving amount in the measured moving direction so that the component force becomes almost zero, it is not necessary to perform the axis alignment and the phase adjustment in advance by another means such as a CCD camera, and the automatic assembly can be performed reliably and smoothly. You can

According to a seventh aspect of the invention, in the controller, the second component is pressed against the first component and then separated.
By repeating the pressing of the second component against the first component again after the axis alignment, it is not necessary to align the axis and the phase in advance, and the axis alignment error can be reduced.

According to the eighth aspect of the invention, in the controller according to the eighth aspect, after the second component is phased with the first component, the rotational direction around the θ axis is as a function of the force Mz measured by the four-axis force sensor. By calculating the correction amount Δθ of the error due to overshoot and rotating the θ axis by this Δθ, it is possible to prevent the first component and the second component from twisting and becoming impossible to assemble.

According to a ninth aspect of the present invention, the controller has a force M in the Z-axis direction measured by the four-axis force sensor.
Determining the direction of rotation about the θ axis as a function of z ensures reliable and smooth assembly.

According to a tenth aspect of the invention, the controller immediately stops the phase matching when the moment about the θ axis becomes larger than a predetermined value during the phase matching of the second part to the first part. Parts and devices can be prevented from damage.

[0042]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. 1 is a front view showing the basic structure of an apparatus according to claim 6 for carrying out the automatic component assembly method according to claims 1 to 5, and FIG. 2 is a partially enlarged view of FIG. The same parts as those in FIG. 1 and 2, reference numeral 10 denotes a four-axis force sensor, and the four-axis force sensor 10 is a wrist tip 8 of the robot 8.
It is provided between a and the Z-axis compliance mechanism 12. As a result, the 4-axis force sensor 10 and the 6-DOF compliance mechanism are formed. This is because the RCC 11 is a compliance mechanism having five degrees of freedom in position and orientation other than the fitting insertion direction, and when the Z-axis compliance mechanism 12 is used together with this, it becomes a compliance mechanism having six degrees of freedom.

FIG. 3 is a perspective view showing the parts to be assembled,
In FIG. 3, 19 is a first part having a square hole 19a, and 20 is a second part having a shaft part 20a having a square chamfer into which the square hole 19a fits.

FIG. 4 is a sectional view showing a component to be assembled and its positioning or component supply, and 21 is the first component 19
Is a positioning mechanism for positioning and holding, and 22 is a component supply mechanism for supplying the second component 20 to the apparatus.

FIG. 5 is a block diagram of the transmission system of the measurement signal of the four-axis force sensor 10, where 51 is the four-axis force sensor 10.
Forces in the X, Y and Z directions Fx, Fy, Fz and θ
An arithmetic unit such as a microcomputer for inputting the moment Mz about the axis and converting each of the forces and moments into movement amounts ΔX, ΔY, ΔZ and Δθ, 52 is a first operation unit according to the movement amount from the operation unit 51. This is a robot controller that relatively moves the components 19 and the second component 20 by the movement amounts ΔX, ΔY, ΔZ, and Δθ.

Next, the operation of the first embodiment will be described. First, the robot 8 is operated and the chuck mechanism 7 holds the second component 20 supplied by the component supply mechanism 22. Then, as shown in FIG. 6, the second component 20 held by the chuck mechanism 7 is moved by moving the robot 8.
Are positioned above the first component 19 positioned by the positioning mechanism 21. Next, the wrist 8a of the robot 8 is lowered to move the second component 20 to the first component 19,
It is pressed with a force greater than the pressing force with which the axis is matched by the action of RCC11.

Then, in the process of lowering the second component 20, the second component 20 is usually slightly off-center with respect to the first component 19. A part of the chamfered portion at the lower end of the shaft portion contacts the upper end of the hole portion of the first component 19. Therefore, as shown in FIG.
A force F1 acts on the component 20 in the arrow direction. The force F1 causes the RCC 11 to act, and the second component 20 moves in the direction in which the axes are aligned. As described above, since the force sensor 10 and the RCC 11 are used together, the axial misalignment amount becomes the deflection of the RCC 11 as shown in FIG.
By detecting the force F2 by the force sensor 10, it becomes possible to detect not only the axial deviation direction but also the axial deviation amount. Therefore, the second component 20 is moved by the RCC 11 in the direction in which the axes are aligned, but the wrist tip of the robot 8 is not moved. Therefore, as shown in FIG. 9, the robot 8 is moved in the horizontal direction. The axis of the second component 20 and the axis of the tip of the wrist of the robot can be aligned.

Even when the axes of the second component 20 and the first component 19 are aligned, the phases are usually slightly shifted. For this reason,
As shown in FIG. 10, a moment M indicated by an arrow acts on the second component 20. Force sensor 1 for phase matching
The same direction as this moment M detected by 0 is set, and the wrist 8 of the robot 8 is set in that direction as shown in FIG.
By rotating a, the force sensor 10 stops the robot 8 at a position where the force in the Z-axis direction changes abruptly. As described above, by using the force sensor 10 and the RCC 11 together, the shaft center and the phase can be matched, and the fitting can be realized quickly and smoothly.

Here, a method of axial center alignment using the force sensor 10 and the RCC 11 together will be described in detail with reference to FIGS. In FIG. 12, reference numeral 26 is a first component having a hole portion 26a having a chamfered portion, and 27 is a second component having a shaft portion 27a into which the hole portion 26a is fitted.

It is assumed that the second component 27 is gripped by the chuck mechanism 7 of the robot 8 and fitted to the first component 26 positioned by the positioning mechanism 19. At that time, in order to align the axes of the second part 27 and the first part 26, a method using only the force sensor 10 and the force sensor 10 and the RCC 1 are used.
A method in which 1 is used in combination will be described. Here, the force pressing the second part 27 against the first part 26 is F, the reaction force that the second part 27 receives from the first part 26 is N, the chamfering angle of the first part 26 is θ, The length of the chamfered slope of the first component 26 is L, and the friction coefficient is μ.

First, a method of aligning the axes with only the force sensor 10 will be described. As shown in FIG. 12, even if the first component 26 is in the state A and the state B, the equation of the vertical balance is μNsin θ + Ncos θ−F = 0∴N = F / (μsin θ + cos θ) .

Therefore, the direction of axial misalignment is determined by the second component 2
It can be detected by measuring the direction of the reaction force N received from the first component 26 by the force sensor 10. On the other hand, regarding the amount of axial misalignment, the magnitude of the reaction force N that the second component 27 receives from the first component 26 is determined by the chamfer angle and the friction coefficient regardless of the state A and the state B. Even if the sensor 10 is used, the amount of axial misalignment cannot be detected.

Therefore, in the case where the force sensor 10 alone is used to align the shaft center, the force sensor 10 detects the direction in which the shaft center is deviated, and the second part 27 is gradually moved in that direction to move the shaft center. Will be combined.

Next, a method of using the force sensor 10 and the RCC 11 together to align the axes will be described. Due to the action of the RCC 11, as shown in FIG. 13, the second component 27 is in a state C in which the axis is aligned regardless of the initial positions of the state A and the state B.
Move to. Therefore, assuming that the horizontal reaction force generated on the second component 27 with the axes aligned is Fx, the axial center deviation is Δx, and the horizontal spring constant of the RCC 11 is K, Fx = KΔx The formula of is established.

That is, the horizontal component force Fx generated on the second component 27 can be measured by the force sensor 10, and the axial misalignment amount Δx can be calculated as Δx = Fx / K.

Therefore, when the force sensor 10 and the RCC 11 are used together to align the axes, the second component 27 is brought into contact with the first component 26 only once, and the direction in which the axes are displaced and the axial displacement are caused. It is possible to detect the amount, and it is possible to align the axis at a higher speed than in the case of only the force sensor 10 that can detect only the direction of the axis deviation.

Next, when the force sensor 10 and the RCC 11 are used together to align the axes, the second part 27 is replaced by the first part 2.
The pressing force when pressing on 6 will be described. When the pressing force F is small, the action of RCC 11 causes
As shown in FIG. 4, the second component 27 moves along the chamfered portion of the first component 26, but does not move to a position where the axes match. Therefore, a certain pressing force or more is required to align the shaft centers by the action of the RCC 11.

The equation of the vertical balance in FIG. 14 is μNsin θ + Ncos θ−F = 0 (1), as in the case of FIG. Further, the equation of the balance in the horizontal direction is −μNcos θ + Nsin θ−KΔx = 0 (2). From the formulas (1) and (2), the pressing force F becomes the following formula. F = (μtan θ + 1) / (− μ + tan θ) * KΔx (3)

Here, the maximum horizontal movement amount ΔXmax of the second component 27 that moves along the chamfer of the first component 26 due to the action of the RCC 11 is determined by the chamfer angle θ and the chamfer slope length L. Then, ΔXmax = L * cos θ, so if this is substituted into equation (3), RCC11
The maximum pressing force Fma required to align the shaft centers with
x is determined as follows. Fmax = (μtan θ + 1) / (− μ + tan θ) * KLcos θ

Therefore, due to the action of the RCC 11, in order to align the shaft center of the second component 27 regardless of the shaft center shift position, it is necessary to make the pressing force equal to or larger than the maximum pressing force Fmax.

Example 2. In the first embodiment, the second component 20 was still pressed against the first component 19 in order to match the shaft center, but the maximum pressing force Fmax is the second.
If the force is large enough to damage the component 20 or the first component 19, the pressing force should be the maximum force that does not damage the component. Therefore, if the shaft center is displaced beyond a certain range, the shaft center will not be perfectly aligned even if it is pressed once.

In such a case, the second component 20 is first pressed against the first component 19 with the maximum force that does not damage the component, and the deviation amount measured by the four-axis force sensor 10 is stored in a memory means (not shown). After storing, the second component 20 is replaced by the first component 1
It is possible to align the shaft center by separating from 9, and moving in the horizontal direction in order to correct the shaft center shift by the shift amount read from the memory means, and pressing it again to the first part 19 again. .

Example 3. In the above-described first or second embodiment, the wrist tip 8a of the robot 8 is rotated about the θ axis to match the phases, and in that state the robot 8 is moved in the fitting insertion direction. In the third embodiment, the force sensor 10 detects the moment Mz around the θ axis for the robot overshoot that occurs due to the problem of responsiveness when the robot 8 is stopped, and then the overshoot amount is calculated to calculate the overshoot amount. Only the tip 8a of the wrist of the robot 8
Is rotated about the θ axis to correct the overshoot, thereby preventing a prying condition that may occur due to the overshoot of the robot 8.

Example 4. 15 to 23 are explanatory views showing the fourth embodiment, and FIG. 15 is a perspective view showing three basic parts of a speed reducer called a harmonic drive. In FIG. 15, 23 is a cup-shaped flexible component (flex spline) having teeth 23a on the outer circumference, 24 is an elliptical rotor (wave generator), and 25 is a ring-shaped component (circular spline) having inner teeth 25a. is there.

As shown in FIG. 16, the assembling work in the fourth embodiment is to insert the circular spline 25 into the flexspline 23 which is deformed into an elliptical shape while aligning the axis and the phase. In the case of assembling, if the circular spline is forcibly inserted in a state where the shaft center and the phase are not aligned, deformation of the flexspline causes a defective assembly, that is, a so-called de-doidal state.

Next, the operation of the fourth embodiment will be described.
First, the robot 8 is operated to cause the chuck mechanism 7 to supply the circular spline 25 supplied by the component supply mechanism.
To hold. Then, as shown in FIG. 17, the robot 8 is moved to position the circular spline 25 gripped by the chuck mechanism 7 above the flex spline 23 positioned by the positioning mechanism 21. Next, the robot 8 is lowered to press the circular spline 25 against the flex spline 23 with a predetermined force, which is equal to or more than the pressing force with which the axis of the RCC 11 matches the axis.

Then, in the process of lowering the circular spline 25, normally the circular spline 25 is
Since the shaft center is slightly deviated from the flexspline 23, the ring-shaped chamfered portion of the circular spline 25 first contacts the chamfered portion of the flexspline 23. Therefore, as shown in FIG. 18, a force F1 indicated by an arrow acts on the circular spline 25. As in the case of the first embodiment, the RCC 11 acts by this force and moves in the direction in which the axes are aligned as shown in FIG.

However, unlike the case of the first embodiment, if the shaft center is deviated beyond a certain range, the shaft center does not completely match, and as shown in FIG. The teeth of the part are caught and the movement stops. This is because the flexspline 23, which is a flexible component, is slightly deformed by the pressing force.

In the case of the fourth embodiment, when the axis is deviated beyond a certain range, the axis cannot be passively aligned only by the RCC 11, so that the robot is pressed with the circular spline 25 against the flexspline 23. No matter how much you move, the axis will not match. Therefore, it is indispensable that the force sensor 10 actively separates the circular spline 25 once and then aligns the axes. Further, in this case, assuming that the forces in the X-axis direction and the Y-axis direction measured by the force sensor 10 are Fx and Fy, the axial misalignment correction amounts Δx and Δy in the X-axis direction and the Y-axis direction are Δx = (1 / K + Cx) * Fx Δy = (1 / K + Cy) * Fy, which is different from the case of the first embodiment, and Cx and Cy have a shape that includes a factor in which the axis center is delicately deviated.

Therefore, in the fourth embodiment, as shown in FIG. 21, the circular spline 25 is raised to a predetermined height of the Z-axis and the robot is moved in the horizontal direction, and the axis of the circular spline 25 and the wrist of the robot are moved. Aligned the tip axis. After that, as shown in FIG. 22, the circular spline 25 is pressed again with a predetermined force on the flex spline 23 to align the shaft center.

Even if the axes of the circular spline 25 and the flex spline 23 are aligned, the phases are usually out of phase as shown in FIG. For this reason, with the axis aligned,
By rotating the circular spline 25 around the θ axis and detecting the force Fz in the Z-axis direction by the force sensor 10, the teeth 25a on the inner circumference of the circular spline 25 and the teeth 23a on the outer circumference of the flexspline 23 are normally meshed. Detect that. Further, by detecting the moment Mz about the θ axis, it is determined whether the teeth 25a on the inner circumference of the circular spline 25 and the teeth on the outer circumference of the flexspline 23 are twisted and meshed with each other.
When z becomes larger than a predetermined value, the rotation of the robot 8 around the θ axis is immediately stopped. If the circular spline 25 is pressed while aligning the phases by this method, minute axis misalignment, phase misalignment, and attitude error
Can be absorbed by CC11, teeth 23a and teeth 25
a is normally engaged, and the assembly is completed.

Example 5. In each of the above embodiments, the force sensor 10 and the RCC 11 are provided on the wrist 8a side of the robot 8 by way of example, but as shown in FIG.
0, RCC 11 and Z-axis compliance mechanism 12 are provided on the positioning mechanism 19 side. Alternatively, as shown in FIG. 25, the force sensor 10 is attached to the wrist 8a side of the robot 8 by the RCC.
11 and Z-axis compliance mechanism 12 are positioning mechanism 1
9 side, or as shown in FIG. 26, the force sensor 10
The RCC 11 and the Z-axis compliance mechanism 12 may be provided on the positioning mechanism 19 side on the wrist 8a side of the robot 8. In particular, when the second part is pressed against the first part, the wrist 8a side of the robot 8 and the positioning mechanism 19 side are integrated, and as shown in FIGS.
Even if the force sensor 10 and the RCC 11 are arranged apart from each other, the bending force of the RCC 11 can be accurately and reliably detected by the force sensor 10.

[0073]

As described above, according to the first aspect of the present invention, the second component is pressed against the first component with a predetermined force in the fitting and inserting direction, and the second component is the first component. Since it is configured to measure the movement direction and movement amount of the robot required to make the component force received from the direction orthogonal to the fitting insertion direction to be substantially zero, it is not necessary to previously match the axis and the phase. is there.

According to the second aspect of the present invention, the second component is pressed against the first component in the fitting and inserting direction with a predetermined force, and the second component receives the fitting and inserting direction from the first component. After measuring the moving direction and the moving amount of the robot required to make the component force in the orthogonal direction substantially zero, the second part is once separated from the first part, and the second part is the first part. Since the robot is moved so that the component force in the direction orthogonal to the fitting insertion direction received from the robot is almost zero, the second component is pressed against the first component again with a predetermined force. Even if the pressing force cannot be increased because there is a possibility that the parts will be damaged, or even if the axes of the parts do not match even if they are brought into contact with each other once, the automatic assembly can be reliably and smoothly performed.

According to the third aspect of the invention, the phase of the second component is changed until the pressing force of the second component in the fitting and inserting direction with respect to the first component becomes smaller than a predetermined magnitude. , The second part receives from the first part the movement direction and the movement amount of the robot necessary to make the moment reaction force around the fitting insertion axis almost zero, and the robot is moved by the measured movement amount. Since it was configured to move,
The second component is inclined by the amount of the clearance from the first component, and the twisted state is unlikely to occur, and there is an effect that automatic assembly can be performed reliably and smoothly.

According to the invention described in claim 4, when the phase of the second component is changed until the pressing force of the second component in the fitting and inserting direction with respect to the first component becomes smaller than a predetermined magnitude, Since the second component is configured to determine the direction of changing the phase of the second component as a function of the moment reaction force about the fitting insertion axis received from the first component, there is an effect that reliable automatic assembly is possible. .

According to the fifth aspect of the invention, while the phase of the second component is changed until the pressing force of the second component in the fitting and inserting direction with respect to the first component becomes smaller than a predetermined magnitude. In addition, when the magnitude of the moment reaction force around the fitting insertion axis received from the first component becomes larger than the predetermined magnitude, the robot operation is configured to be stopped immediately, so that the component is prevented from being damaged. You can

According to the sixth aspect of the invention, the second component is pressed against the first component in a fitting and inserting direction with a predetermined force, and
The axial force sensor measures the movement direction and movement amount of the robot necessary for making the component force in the direction orthogonal to the fitting insertion direction that the second component receives from the first component to be almost zero, Since the robot is configured to move so that the component force received by the first component from the first component in the direction orthogonal to the fitting and inserting direction is substantially zero, the component automatic assembly apparatus that does not need to match the axis and the phase in advance. There is an effect that can be obtained.

According to the seventh aspect of the invention, the second component is pressed against the first component in the fitting and inserting direction with a predetermined force, and then the second component is once separated from the first component, Second
Moves so that the component force received from the first component in the direction orthogonal to the fitting insertion direction becomes almost zero, and again the second component is fitted to the first component with a predetermined force in the fitting insertion direction. Since it is configured to be pressed again, there is a possibility of damaging the parts.Therefore, even if the pressing force cannot be increased, or if the shaft center does not match even if only one contact is made from the contact state of the parts, it can be performed securely and smoothly. There is an effect that can be automatically assembled.

According to the eighth aspect of the invention, the phase of the second component is changed until the pressing force of the second component in the fitting and inserting direction with respect to the first component becomes smaller than a predetermined magnitude. , The second part receives from the first part the movement direction and the movement amount of the robot necessary to make the moment reaction force around the fitting insertion axis almost zero, and the robot is moved by the measured movement amount. Since it was configured to move,
This has the effect of preventing the second part from tilting by the amount of the clearance from the first part and twisting into a disengageable state.

According to the invention of claim 9, when the phase of the second component is changed until the pressing force of the second component in the fitting and inserting direction with respect to the first component becomes smaller than a predetermined magnitude, The second component is configured to determine the direction in which the phase of the second component is changed as a function of the moment reaction force about the fitting insertion axis received from the first component, so that the secure fitting can be achieved. effective.

According to the tenth aspect of the present invention, while changing the phase of the second component until the pressing force of the second component in the fitting and inserting direction with respect to the first component becomes smaller than a predetermined magnitude. In addition, when the magnitude of the moment reaction force around the fitting insertion axis received from the first component becomes larger than a predetermined magnitude, the operation of the robot is immediately stopped. This has the effect of preventing some from being damaged.

[Brief description of drawings]

FIG. 1 is a front view showing a basic configuration of an automatic parts assembly apparatus according to an embodiment of the invention as claimed in claim 6 for carrying out the parts automatic assembly method as claimed in claims 1 to 5.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a perspective view showing an assembly target component.

FIG. 4 is a cross-sectional view showing positioning of an assembly target component and supply of the component.

FIG. 5 is a configuration diagram of a measurement signal transmission system of a four-axis force sensor.

FIG. 6 is a front view for explaining an automatic component assembling method according to an embodiment of the invention described in claims 1, 2, and 5.

FIG. 7 is a front view for explaining an automatic component assembling method according to an embodiment of the invention described in claims 1, 2, and 5.

FIG. 8 is a front view for explaining an automatic component assembling method according to an embodiment of the invention described in claims 1, 2, and 5.

FIG. 9 is a front view for explaining an automatic component assembling method according to an embodiment of the invention described in claims 1, 2, and 5.

FIG. 10 is a plan view illustrating an automatic component assembling method according to an embodiment of the invention described in claims 3 to 5;

FIG. 11 is a front view for explaining an automatic component assembling method according to an embodiment of the invention described in claims 3 to 5.

FIG. 12 is an explanatory diagram of axis alignment using a 4-axis force sensor and RCC together.

FIG. 13 is an explanatory diagram of axis alignment using a 4-axis force sensor and RCC together.

FIG. 14 is an explanatory diagram of axis alignment using a 4-axis force sensor and RCC together.

FIG. 15 is a perspective view showing a component to be assembled.

FIG. 16 is a perspective view showing an assembled state of parts to be assembled.

FIG. 17 is a front view for explaining the operation of the automatic component assembly apparatus in an embodiment of the invention as set forth in claims 6 to 10;

FIG. 18 is a front view for explaining the operation of the automatic component assembly apparatus in an embodiment of the invention as claimed in claims 6 to 10;

FIG. 19 is a front view for explaining the operation of the automatic component assembly apparatus in an embodiment of the invention as set forth in claims 6 to 10;

FIG. 20 is a plan view showing a slight misalignment of the axes of the parts to be assembled.

FIG. 21 is a front view for explaining the operation of the automatic component assembly apparatus in an embodiment of the invention as set forth in claims 6 to 10;

FIG. 22 is a front view for explaining the operation of the automatic component assembly apparatus in an embodiment of the invention as set forth in claims 6 to 10;

FIG. 23 is a plan view showing a phase shift of an assembly target component.

FIG. 24 is a schematic diagram showing another basic configuration of the automatic component assembly apparatus in an embodiment of the invention as claimed in claims 6 to 10;

FIG. 25 is a schematic view showing still another basic configuration of the automatic component assembly apparatus in one embodiment of the invention as claimed in claims 6 to 10.

FIG. 26 is a schematic diagram showing still another basic configuration of the automatic component assembly apparatus in one embodiment of the invention as claimed in claims 6 to 10.

FIG. 27 is a front view showing the basic configuration of a conventional automatic assembly apparatus.

28 is a partially enlarged view of FIG. 27.

FIG. 29 is a perspective view showing a component to be assembled.

FIG. 30 is a cross-sectional view showing positioning of an assembly target component and supply of the component.

FIG. 31 is a front view illustrating the operation of the conventional automatic assembly apparatus.

FIG. 32 is a side sectional view for explaining the operation of the conventional automatic assembly apparatus.

FIG. 33 is a plan view for explaining the operation of the conventional automatic assembly apparatus.

[Explanation of symbols]

 5,19,26 First part 6,20,27 Second part 7 Chuck mechanism 8 Robot 9 Coupling mechanism 10 Force sensor 11 RCC 21 Positioning mechanism

Claims (10)

[Claims] 1. A positioning step of positioning a first part, a pressing step of moving a second part with respect to the first part and pressing the first part in a fitting and inserting direction with respect to the first part, A calculation step of calculating a movement direction and a movement amount of the second component, which is necessary for making the component force of the second component received from the first component orthogonal to the fitting insertion direction, substantially zero; An axial aligning step of moving the second component in the calculated moving direction to substantially zero the component force received from the first component and orthogonal to the fitting and inserting direction; A phase matching step of moving the pressing force in the fitting insertion direction received from a component so as to be smaller than a predetermined value; and an inserting step of moving the second component in the fitting insertion direction with respect to the first component. A method for automatically assembling parts, characterized in that the steps are sequentially executed. 2. A separating step of separating the second part from the first part after the calculating step, and a fitting step of the second part to the first part after the axis aligning step. 2. The component automatic assembly method according to claim 1, further comprising a re-pressing step of pressing again with a predetermined force in the insertion direction. 3. After the phase matching step, the rotation direction and the rotation amount of the second component necessary to make the moment reaction force around the fitting insertion axis received from the first component almost zero are calculated, and 3. The automatic component assembly method according to claim 1, further comprising: performing a rotating step of rotating the second component by the calculated rotation amount. 4. The direction in which the phase of the second part is changed is determined as a function of the moment reaction force about the fitting insertion axis that the second part receives from the first part. The automatic component assembly method according to any one of claims 1 to 3. 5. When the moment reaction force around the fitting insertion axis becomes larger than a predetermined value during the phase matching step,
5. The component automatic assembly method according to claim 1, wherein the phase matching step is immediately stopped. 6. A Z-axis direction coinciding with the mating insertion direction, an X-axis direction orthogonal to the Z-axis direction, a Y-axis direction orthogonal to the Z-axis direction and the X-axis direction, and rotation about the Z-axis direction. A robot that relatively moves in four directions along the θ axis and a first
Of the positioning mechanism for positioning the component, and the robot and the positioning mechanism, which have six degrees of freedom in the position and orientation with the vicinity of the tip of the second component chucked by the chuck mechanism as the compliance center. A compliance mechanism having compliance and a four-axis force sense that measures the forces Fx, Fy, Fz in the X-axis direction, the Y-axis direction, and the Z-axis direction acting on the compliance mechanism and the moment Mz about the θ-axis. The sensor and the second component gripped by the chuck mechanism are moved with respect to the positioned first component so that the force Fz measured by the four-axis force sensor falls within a predetermined range. The pressing step of pressing the second component against the first component, the forces Fx and Fy measured by the four-axis force sensor. As a function, the calculation step of calculating the error correction amounts Δx and Δy of the robot in the X and Y directions, the axis alignment step of moving the robot by the error correction amounts Δx and Δy, and the θ axis of the robot are A phase matching step of rotating until the force Fz measured by the axial force sensor is sufficiently small, and an inserting step of moving the robot in the Z direction to insert the second component into the first component are sequentially executed. A component automatic assembly device including a controller. 7. The controller, after the calculation step,
After the step of moving the chuck mechanism in the Z direction to separate the second part from the first part, and after the axis aligning step, the chuck mechanism is moved in the Z direction to move
It has a function of sequentially executing a re-pressing step of pressing the second component again against the first component so that the force Fz measured by the axial force sensor falls within a predetermined range. The automatic component assembly apparatus according to claim 6. 8. The controller, after the phasing step, calculates a correction amount Δθ of an error due to overshoot in a rotation direction of the robot about a θ axis as a function of a force Mz measured by the four-axis force sensor. However, it has a function of executing a rotating step of rotating the θ axis of the robot by this Δθ.
The described automatic component assembly apparatus. 9. The controller has a function of determining a rotation direction around the θ axis of the robot as a function of a force Mz in the Z direction measured by the four-axis force sensor. 9. The parts automatic assembly apparatus according to any one of 6 to 8. 10. The controller causes the robot to rotate about the θ axis when the moment Mz about the θ axis measured by the four-axis force sensor becomes larger than a predetermined value during the phasing step. 10. The parts automatic assembly apparatus according to claim 6, further comprising a function of stopping it immediately.