JPH0623629A - Assembly method and device - Google Patents

Abstract

(57) [Abstract] [Purpose] An assembly method for attaching a component to a block by using a movable hand that supports the component, and an assembling method for preventing an excessive force from being applied to the component when the component is brought into contact with the block. An object of the present invention is to provide a device, which comprises: a step of causing a component 2 supported by a hand 1 to face a component mounting position of a block 3; and a positioning control in a direction from the facing portion to the component mounting position. The step of bringing the component 2 close to the block 3 until just before the component 2 comes into contact with the block 3, the step of switching the positioning control to the compliance control and bringing the component 2 into contact with the block, and the part where it comes into contact 2 has a step of fixing the block 2 to the block 3 and a step of releasing the support of the component 2 and withdrawing the hand 1 after the fixing. The device adds a compliance control unit 10, a short-distance sensor 4, a distance determination unit 11, and the like that control switching to the compliance control unit 10 to the device that controls positioning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembling method and apparatus, and more particularly to an assembling method for attaching a component to a block by using a movable hand that supports the component.

The above-mentioned assembly is often used for automation of assembly work in the FA (Factory-Automation) field by utilizing vacuum suction for supporting the parts, and the parts are particularly thin plate-shaped and difficult to handle. This is effective in the case where it is a disk that does not have a slight scratch like the disk of a magnetic disk. Recently, parts that are easily deformed other than metal, such as cloth and leather, have come to be handled.

Therefore, it is desired that an excessive force is not applied to the component when the component is brought into contact with the block for mounting the component.

[0004]

2. Description of the Related Art FIG. 7 is a perspective view showing an assembly according to the present invention. In this assembly, the component 2 is attached in a state in which the component 2 is applied to the component attachment position on the XY plane of the block 3 from the Z direction.

FIG. 8 is a side view showing the assembling operation of the conventional example. In FIG. 8, first, as shown in (a), the component 1 is supported by vacuum suction on the hand 1 arranged at the tip of the automatic machine by the robot or the multi-axis stage (f _H is the force supporting the hand 1 side). The component 2 is opposed to the component mounting position of the block 3 by the positioning control of the hand 1. Then, as shown in (b), Z toward the component mounting position
The hand 1 is moved in the direction by the positioning control described above, and the part 2 is moved.
Stop at the position where it contacts block 3. Therefore, the component 2 is fixed to the block 3 by vacuum suction from the block 3 side (f _B represents the force for fixing to the block 3 side). Next, as shown in (c), the hand 1 withdraws the suction of the component 2 and leaves the component 2 on the block 3 side while leaving.

[0006]

However, in the assembly of this conventional example, since the positioning control is used for the approach of the hand 1 to the block 3, the contact state in the complete sense is actually shown in FIG. 8 (b). Difficult to realize.
That is, FIG. 9 is a side view for explaining the problems of the conventional example, and the position of the hand 1 is the block 3 as shown in FIG.
If the component 2 is subjected to an excessive pressure F _P between the hand 1 and the block 3, the hand 1 stops before the component abuts the block 3 as shown in FIG. 9B. It will be either of the cases. In the former case, the pressure F _P
As a result, the component 2, the hand 1, or the block 3 is deformed or damaged. On the other hand, in the latter case,
Since the component 2 is sucked from the block while floating in the air, it is difficult to accurately mount the component 2 at the component mounting position of the block 3.

Further, when the movement of the hand 1 is set by teaching, even if a large number of man-hours are applied to the teaching of the position where the component 2 abuts on the block 3, the accuracy is the same as the above.

The present invention relates to an assembly for attaching a component to a block by using a movable hand that supports the component, and an assembly that can prevent an excessive force from being applied to the component when the component is brought into contact with the block. To provide a method and an apparatus

[0009]

FIG. 1 is a diagram for explaining the principle of the present invention, in which (a1) to (a4) are side views showing an assembling operation, and (b) is a main part configuration of an assembling apparatus. It is a figure.

In order to achieve the above object, an assembly method according to the present invention will be described with reference to FIGS. 1 (a1) to 1 (a4).
In the assembly for attaching the component 2 to the block 3 using the movable hand 1 that supports the component 2, as shown in FIG. 1A1, the component 2 supported by the hand 1 with force f _H is placed at the component attachment position of the block 3. Step of facing each other, and FIG. 1 (a2)
As shown in FIG. 1A3, the step of bringing the component 2 close to the block 3 until just before the component 2 comes into contact with the block 3 by the positioning control in the direction from the facing portion to the component mounting position as shown in FIG. , The position control is switched to the compliance control at the position of the proximity, and the component 2
1 is brought into contact with the block 3, and the part 2 is fixed to the block 3 with a force f _B when the contact is made.
As in (a4), there is a step in which the hand 1 releases the support of the component 2 and retreats after the fixing.

At this time, it is desirable that the proximity position is detected by a short-distance sensor 4 which is fixed to the hand 1 and measures the distance to the block 3, and the compliance control is performed by a compliance constant and a parameter which are parameters. It is desirable that the setting of the compliance center position is variable.

Then, the assembling apparatus is capable of supporting the part 2 and releasing the support, with reference to FIG. 1 (b) showing only the Z axis which is the direction in which the part 2 is brought into contact with the block 3. , A hand 1 that moves a plurality of axes by driving the actuator 5 for each axis, a position sensor 6 for each axis that detects the drive amount of the actuator 5 for each axis, and a hand 1 for each axis. Position sensor 6 to move to the specified position.
Position control unit 9 (operation output u) for each axis for controlling the actuator 5 based on the signal (position Z), and one axis (Z axis) for bringing the component 2 of the plurality of axes into contact with the block 3. In the above, the compliance control unit 10 is switched from the positioning control unit 9 so that the movement of the hand 1 for the corresponding contact becomes compliance control, and the distance to the block 3 fixed to the hand 1 in the 1-axis (Z-axis) direction. And a distance determination unit 11 that performs the switching from the positioning control unit 9 to the compliance control unit 10 when the measurement distance s of the short distance sensor 4 becomes smaller than a specified value. It is characterized by that. In the figure, 7 is a drive mechanism interposed between the actuator 5 and the hand 1, and 8 is a controller including the control units 9 and 10 and the determination unit 11.

[0013]

2 is a side view showing a state in which the parts of the present invention are in contact with the block. In the above assembling method, since the movement of the hand 1 when the component 2 is brought into contact with the block 3 is performed by compliance control, the contact is as shown in FIG.

In FIG. 2, Z is the position of the surface of the hand 1 holding the component 2, Z ₀ is the compliance center position, ΔZ is the deviation represented by ΔZ = Z−Z ₀ , and f _c is the compliance control. The force by which the hand 1 presses the component 2 (compliance setting force), and the compliance constant is C, the force f _c is represented by f _c = ΔZ / C. Therefore, in the compliance control, the deviation ΔZ can be set appropriately, and it is possible to prevent an excessive force from being applied to the component 2 when the component 2 is brought into contact with the block 3. Note that f _H in FIG. 2 is a force for supporting the component 2 on the hand 1 side, and f _B is a force for fixing the component 2 on the block 3 side after the contact.

In this assembling method, detecting the close position by the short distance sensor 4 has an advantage that the position at which the position control is switched to the compliance control can be accurately controlled. Further, the variable setting of the above-mentioned parameters of the compliance control includes the fact that the compliance constant C can be set appropriately, which is advantageous for reducing the force f _C.

The above-mentioned assembling apparatus can perform the above-described assembling method depending on its configuration.

[0017]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 3 is a block diagram of a mechanism unit of an assembling apparatus in the embodiment, FIG. 4 is a block diagram of a controller in the embodiment, FIG. 5 is a block diagram of Z-axis control in the embodiment,
FIG. 6 is an operation explanatory diagram before switching the Z-axis control in the embodiment.

In FIG. 3, the mechanical unit of the assembling apparatus is based on an XYZ-γ stage.
1, the Y-axis base 22, and the Z-axis arm 23, the Z-axis arm 23 moves in the same three-axis directions by the movement control of the XYZ 3-axis, and the Z-axis arm 2
A hand 1 that is γ-axis controlled (rotationally controlled) and a short-distance sensor 4 that measures the distance to the block 3 described above are provided at the tip of 3, and a force in the Z-axis direction applied to the hand 1 (see The strain sensor 12 for measuring f) is provided and controlled as shown in FIG. The hand 1 can support the above-mentioned component 2 by vacuum suction as in the case of the conventional example.

In FIG. 4, DC motors 5x, 5y, 5
z and 5γ correspond to the above-mentioned actuator 5 and drive the movement of the hand 1 in the X-axis, Y-axis, Z-axis and γ-axis directions. Incremental encoder 6x, 6y, 6z, 6
γ corresponds to the position sensor 6 described above and corresponds to the DC motors 5x, 5
The drive amounts of y, 5z, and 5γ, that is, the movement amounts in the X-axis, Y-axis, Z-axis, and γ-axis directions are detected. These are directly connected to the mechanical section.

The controller 8 corresponds to the above-mentioned positioning control unit 9 and performs positioning control units 9x, 9y, 9z, 9γ corresponding to the X-axis, Y-axis, Z-axis, and γ-axis, and the Z-axis compliance control described above. Compliance control unit 10
The distance determination unit 11, the short distance sensor 4 and the strain sensor 1 described above.
A / D converters 13 and 14 for A / D converting the second signal,
Amplifier (AMP) 15x, 15y, 15z, 1 for each axis
5γ.

When the component 2 is attached to the block 3 as shown in FIG. 7, the incremental encoders 6x, 6y, 6 are supported after the component 2 is supported by the hand 1.
Upon receiving the signals of z and 6γ, the component 2 on the hand 1 is made to face the component mounting position of the block 3 and approach the block 3 by the positioning control in the X-axis, Y-axis, Z-axis, and γ-axis directions. When the distance to the block 3 measured by the short distance sensor 4 becomes smaller than a specified value in the approaching process performed as a movement in the Z-axis direction, the distance determining unit 1
By switching from the Z-axis positioning control unit 9z to the compliance control unit 10 by 1, the movement of the hand 1 in the Z direction is switched to compliance control. The specified value is the control mode switching set distance, and is set so that the switching is performed before the component 2 on the hand 1 comes into close contact with the block 3. After this switching, the component 2 is brought into contact with the block 3 while performing compliance control. In the strain sensor 12, the measured value of the force f appears from the time when the component 2 contacts the block 3.

The control of the Z axis described above is performed as shown in FIG. The terminal a of the SW is on the side of the positioning controller 9z, and the terminal b is on the side of the compliance controller 10.
In the figure, R ₀ is a positioning position by positioning control, r is a target position, v is a target speed, e is a position deviation, u is an operation output,
Z is the current position in the Z-axis direction, f is the force measured by the strain sensor 12, Z ₀ is the aforementioned compliance center position, f _c is the aforementioned compliance setting force, C is the aforementioned compliance constant, and k is the target speed generation gain. ,. As a result, the component 2 comes into contact with the block 3 and the Z of the hand 1
When the movement in the direction is stopped, the state described above with reference to FIG. 2 is obtained.

Immediately before switching to the compliance control, the distance to the block 3 of the hand 1 is monitored by the short-distance sensor 4 and the target position r is controlled while being updated as shown in FIG. In the figure, r ₀ is the position at which sensing by the short-range sensor 4 is started, t ₀ is the time at that time, r _n is the position for switching to compliance control (control mode switching set distance viewed from the position sensor 4), t _n is the current position , R ₁ , r ₂ , ... Are positions at equal intervals between r ₀ and r _n, and t ₁ , t ₂ , ... Are positions r ₁ , r ₂ ,
It is time to respond to. Time t ₁ , t ₂ , ...
The control is performed so that the steps of are evenly spaced so that the switching to the compliance control is performed at an accurate position.

In the mounting of the component 2 advanced to the state of FIG. 2 in this way, the component 2 abutting on the block 3 is fixed to the block 3, the support of the component 2 by the hand 1 is released, and the controller 8 is positioned. The hand 1 is evacuated by the control to complete the process.

In the attachment of the component 2 described above, the compliance constant C, which is a parameter of the compliance control, is determined from the configuration of the mechanical unit of the assembling apparatus and the controller 8.
Since the compliance center position Z ₀ can be set arbitrarily, the force (compliance setting force f _c ) received from the block 3 when the component 2 contacts the block 3
Can be any size, and its force is
As described in (a), it is possible to avoid becoming excessive. In addition, the state of FIG. 9B in which the component 2 stops before contacting the block 3 does not occur. Of course, it is not necessary to specify the position where the component 2 is brought into contact with the block 3, which is required in the conventional example.

[0026]

As described above, according to the present invention, an assembly for attaching a component to a block by using a movable hand that supports the component, and when the component is brought into contact with the block, an excessive force is applied to the component. An assembly method and device that can prevent the parts from being provided are provided so that the parts can be always attached in the correct positions without damaging the parts, and particularly when handling parts that are easily damaged or deformed. This is effective and does not require fine adjustment of the contact position of the component with respect to the block. Therefore, when the movement of the hand is set by teaching, the number of steps can be significantly reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of the principle of the present invention.

FIG. 2 is a side view showing a state in which a component of the present invention is in contact with a block.

FIG. 3 is a configuration diagram of a mechanical unit of an assembling apparatus according to an embodiment.

FIG. 4 is a block diagram of a controller according to an embodiment.

FIG. 5 is a block diagram of Z-axis control in the embodiment.

FIG. 6 is an operation explanatory diagram before switching the Z-axis control in the embodiment.

FIG. 7 is a perspective view showing an assembly according to the present invention.

FIG. 8 is a side view showing an assembling operation of a conventional example.

FIG. 9 is a side view for explaining the problems of the conventional example.

[Explanation of symbols]

1 Hand 2 Parts 3 Block 4 Short Distance Sensor 5 Actuator 5x, 5y, 5z, 5γ Actuator DC Motor 6 Position Sensor 6x, 6y, 6z, 6γ Position Sensor Incremental Encoder 7 Drive Mechanism 8 Controller 9, 9x, 9y , 9z, 9γ Positioning control unit 10 Compliance control unit 11 Distance determination unit 12 Strain sensor 13, 14 A / D conversion unit 15x, 15y, 15z, 15γ Amplifier (AMP) 21 X-axis base 22 Y-axis base 23 Z-axis arm Z Position of the component holding surface of the hand (current position in the Z-axis direction) Z ₀ Compliance center position ΔZ ΔZ = Z−Z ₀ deviation C Compliance constant f _c Compliance setting force f _H Force to support the component on the hand side force R ₀ positioning control by the positioning position for fixing the f _B component in the block side position to switch to time r _n compliance control corresponding to the r target position v target speed e position deviation u manipulated output f strain sensor starts sensing by force k target speed generating gain r ₀ short range sensor measured position t ₀ r ₀ time corresponding to t _n r _n

Claims (4)

[Claims] 1. In an assembly for attaching a component to a block using a movable hand that supports the component, a step of causing the component supported by the hand to face a component attachment position of the block; Positioning control in the direction toward the component mounting position brings the component closer to the block until just before the component comes into contact with the block; and when the proximity comes, the positioning control is switched to compliance control to move the component to the block. And a step of fixing the component to the block when the contact is made, and a step of releasing the support of the component by the hand and retreating after the fixing. Method. 2. The assembling method according to claim 1, wherein the proximity position is detected by a short-range sensor that is fixed to the hand and measures a distance to the block. 3. The assembling method according to claim 1, wherein in the compliance control, setting of a compliance constant and a compliance center position as parameters are variable. 4. An assembling apparatus for performing the assembling method according to any one of claims 1 to 3, wherein a plurality of axes can be supported by supporting a component to be attached and releasing the support, and driving an actuator for each axis. And a position sensor for each axis that detects the drive amount of the actuator for each axis, and a signal for the position sensor so that the hand moves to a designated position for each axis. In the positioning control section for each of the axes that controls the actuator based on the above, and in the one axis that brings the parts of the plurality of axes into contact with the block, the movement of the hand for the corresponding contact becomes compliance control. A compliance control unit that switches from the positioning control unit, a short-range sensor that is fixed to the hand and measures the distance to the block in the one-axis direction, and a measurement distance of the short-range sensor is specified. And a distance determining unit that performs the switching from the positioning control unit to the compliance control unit when the value becomes smaller than the value.