JPH038917B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting the position of a workpiece transported by a transport device in a direction orthogonal to the transport direction.

When a vehicle body is transported by a transport device and a robot placed parallel to the transport device performs painting, welding, or sealing work on the vehicle body, the position of the vehicle body in the transport direction and in the direction orthogonal to the transport direction must be accurately determined. Detection is required. By the way, when trying to detect the position of the car body in the direction perpendicular to the transport direction by contacting the car body, it is necessary to prevent damage such as scratches to the car body, and it is necessary to automatically detect the position of the car body in the direction perpendicular to the transport direction. Preferably, a contact action is performed.

The present invention has been made in view of the above points,
The purpose of this is a position detection device for a workpiece that can automatically contact the workpiece and detect its position in a direction perpendicular to the transport direction of the vehicle body, without damaging the workpiece. Our goal is to provide the following.

According to the present invention, the object is to provide a position detection device for detecting the position of a workpiece transported by a transport device in a direction perpendicular to the transport direction, which includes a base body and a base plate having one end side attached to the base body. An arm is rotatably supported, and one end is rotatably supported by the arm and the other end is rotatably supported by the base so that the other end of the arm can be moved toward and away from the workpiece. a cylinder supported rotatably; a spring member having one end attached to the arm and the other end attached to the base so as to press the other end of the arm against the workpiece; Detection for detecting the amount of rotation of the cylinder with respect to the base when the other end of the arm approaches the workpiece by a predetermined distance and the cylinder can rotate integrally with the arm. This is achieved by a position detecting device for a workpiece having a device.

Next, preferred embodiments of the present invention will be explained based on the drawings.

In the figure, brackets 2 and 3 fixed to a support base 1 are provided with a shaft 5 rotatably via a bearing 4, and one end of an arm 7 is rotatably provided on the shaft 5 via a bearing 6. A roller 8 made of urethane rubber or the like is attached to the tip of the arm 7 so as to be rotatable in the A direction about the center line 9 of the arm 7. One end of a piston rod 13 of a cylinder 12 operated by air is rotatably attached to a shaft 10 attached to the arm 7 via a bearing 11.
The second cylinder body 14 is rotatably attached to one end of a support member 16 via a shaft 15, and the other end of the support member 16 is fixed to the shaft 5 by a pin 17.

Incidentally, the aforementioned support stand 1, bracket 2, bracket 3, and support member 16 each constitute a base. Coil spring 18 as a spring member
One end of the spring 18 is attached to the shaft 10, and the other end of the spring 18 is attached to a pin 19 implanted in the bracket 2. A gear 21 meshes with a gear 20 fixed to one end of the shaft 5, and the gear 21 is fixed to a rotating shaft 23 of a rotary encoder 22 as a detector attached to the bracket 3. In the stoppers 24 and 25 provided by bridging the brackets 2 and 3, the stopper 24 has a B centered on the axis 5 of the support member 16.
The stopper 25 prevents rotation in the direction beyond a certain amount.
prevents rotation of more than a certain amount in the direction opposite to the B direction, that is, the C direction. Two chambers 27 and 28 defined by the piston 26 within the cylinder body 14
, the chamber 27 is connected to a compressed air source 32 via a one-way valve 29, a variable throttle passage 30, and a solenoid valve 31.
Furthermore, the chamber 28 is communicated with a compressed air source 32 via a one-way valve 33, a variable throttle passage 34, and a solenoid valve 31, respectively. Valve 31 is actuated by a signal from control device 35. The control device 35 has an up-down counter 36 that receives two electrical signals from the encoder 22 resulting from the rotation of the shaft 23 in directions B and C;
When the shaft 23 rotates in the B direction, a signal indicating the amount of rotation in the B direction supplied from the encoder 22 is integrated, and this integrated value is converted into a signal indicating the amount of rotation in the C direction supplied from the encoder 22 when the shaft 23 rotates in the C direction. Subtract by.

A vehicle body 37 as a workpiece is placed on a transport device 39 running on rails 38 and transported in the D direction. In order to detect when the vehicle body 37 reaches a predetermined position in the transport direction, that is, in the D direction, a photoelectric exchanger 41 of the light emitter 40 is installed downstream in the D direction.
An optical detector 42 is provided, comprising:
A detection signal from the detector 42 is supplied to the control device 35. The articulated robot main body 44, which is placed on a moving device 43 so as to be moved in a direction parallel to the conveyance direction of the vehicle body 37, that is, in the D direction and the E direction opposite to this, is moved according to a program taught and stored in advance. For example, painting work is performed on the vehicle body 37 using the data.

The workpiece position detection device 50 configured in this way is arranged near the rail 38 in the painting work area. To explain the operation of detecting the position of the vehicle body 37 in a direction perpendicular to the D direction, that is, in the F direction, by the device 50, first, before the detection operation, the valve 31 is set to the state shown in FIG. The air-operated cylinder 12 is most compressed, the support member 16 is urged by the spring 18 and abuts against the stopper 25, and the arm 7
is set at position 51. When the vehicle body 37 is transported in the D direction by the transport device 39 and the light from the light emitter 40 is blocked by the vehicle body 37, the photoelectric converter 41 no longer receives light, and as a result, the detector 42 controls the signal indicating the arrival of the vehicle body 37. Upon receiving this signal, the control device 35 causes the compressed air of the source 32 to be supplied to the chamber 27 via the valves 31, 29 and the throttle passage 30, while the compressed air of the chamber 28 is throttled. The valve 31 is set so that it is discharged to the outside via the passage 34 and the valve 31. When compressed air is supplied to the chamber 27, the rod 13 begins to protrude in the F direction, and due to the protrusion of the rod 13 in the F direction, only the arm 7 is first rotated in the B direction about the shaft 5. During the rotation of arm 7 in direction B, shaft 5
When the center line 52 of the spring 18 passes through the center of the shaft 5, a force is generated by the spring 18 that rotates the arm 7 in the direction B, and the arm 7 crosses the vertical line 53 passing through the center of the shaft 5 and moves the arm 7 in the direction B. When the arm 7 is rotated in the direction B, the weight of the arm 7 also causes the arm 7 to
A force is generated that causes the object to rotate in the direction. When all the rods 13 are protruded from the cylinder body 14, the piston 26 and the cylinder body 14 come into contact with each other, so that the arm 7 rotates in the B direction due to the tension of the spring 18 and the weight of the arm 7, and is actuated by air. The cylinder 12 and support member 16 are also rotated in the B direction about the shaft 5, and as a result, the gears 20 and 21 are rotated, and the encoder 22 generates a signal indicating the amount of rotation in the B direction. counter 36
is counted. When the arm 7 is further rotated in the B direction, the roller 8 comes into contact with the side surface of the vehicle body 37, and as a result, the arm 7 is prevented from rotating in the B direction. After a predetermined period of time has elapsed since receiving the vehicle body arrival signal from the detector 42, the control device 35 causes the solenoid valve 31 to be set again to the state shown in FIG.
The integrated value, that is, the detected position of the vehicle body 37 in the F direction is supplied to the control device of the robot body 44. As a result, the compressed air from the source 32 is supplied to the chamber 28 via the valves 31, 33 and the passage 34, while the compressed air from the chamber 27 is discharged to the outside via the passage 30 and the valve 31, and 13 begins to be moved in the G direction. Even when the rod 13 moves in the G direction, the arm 7 is moved relative to the support member 16 by the axis 5
The spring 18 is rotated in the C direction around
When a rotational torque in the C direction is applied to the arm 7 due to its own weight, the support member 16 is also rotated in the C direction and comes into contact with the stopper 25 . As a result of the rotation of the support member 16 in the C direction, the shaft 23 is rotated, and as a result, the encoder 22 outputs a signal for subtracting the integrated content of the counter 36, and the contact of the support member 16 with the stopper 25 causes the counter 36 to decrease. The content becomes zero. Furthermore, by supplying compressed air to the chamber 28, the rod 13 is moved in the G direction,
Arm 7 is finally reset to position 51. The control device of the robot body 44 determines the difference between the detected position in the direction orthogonal to the D direction, that is, the F direction, supplied from the counter 36 and a preset reference position, and uses this difference to correct the stored program data. In addition, the main body 44 is activated. The above operations are repeated each time a new vehicle body is transported one after another. The stopper 24 is the arm 7
In order to prevent the support member 16 from being rotated too much in the B direction and the arm 7 not being reset to the position 51 even when the rod 13 is moved in the G direction,
The support member 16 is prevented from rotating beyond a certain amount in the B direction.

Note that if the vehicle body 37 is displaced by a certain amount or more in the direction F perpendicular to the direction D, an alarm may be activated. Alternatively, the tensile force of the coil spring 18 may be set to be extremely small so that the roller 8 comes into contact with the vehicle body 37 due to the arm 7's own weight.

As described above, the workpiece position detection device 50 of this specific example is a position detection device that detects the position of the vehicle body 37, which is the workpiece transported by the transport device 39, in the direction orthogonal to the transport direction. A base constituted by the support stand 1, the bracket 2, the bracket 3, and the support member 16, an arm 7 rotatably supported at one end by the base, and the other parts of the arm 7. Approach the car body 37 with the end side.
A cylinder 12 has one end rotatably supported by the arm 7 and the other end rotatably supported by the support member 16 of the base, and the other end of the arm 7 is connected to the vehicle body 37. A spring 18, which is a spring member whose one end is attached to the arm 7 and the other end is attached to the bracket 2 of the base so that it can be pressed, and the cylinder 12 cause the other end of the arm 7 to be attached to the vehicle body 37 in a predetermined position. and a rotary encoder 22 for detecting the amount of rotation of the cylinder 12 with respect to the brackets 2 and 3 of the base when the cylinder 12 can rotate integrally with the arm 7 when the cylinder 12 approaches the arm 7 at a distance. There is.

As described above, according to the workpiece position detection device of the present invention, by appropriately selecting the elastic modulus of the spring member, the other end side of the arm can be brought into contact with the workpiece with an extremely weak force, and the Since the contact can be maintained reliably, the position detection operation can be performed reliably with less risk of damaging the workpiece.

In addition, according to the workpiece position detection device of the present invention, the cylinder can perform an operation of bringing the arm closer to the workpiece by a predetermined distance, that is, rotation of the arm to a predetermined position. Therefore, the detection operation of the position detecting device can be performed automatically and quickly.

In addition, according to the workpiece position detection device of the present invention, the other end of the arm approaches the workpiece by a predetermined distance due to the operation of the cylinder, and the cylinder rotates integrally with the arm. Since the detector is configured to detect the amount of rotation of the cylinder relative to the base when the arm can move, the detector detects the rotation amount only in the rotation range necessary for position detection operation within the rotation range of the arm. As a result, the position detection resolution of the detector can be increased, and changes in the position of the workpiece can be detected with increased accuracy.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a preferred embodiment of the present invention applied to a car body painting line, Fig. 2 is a side view of the car body painting line shown in Fig. 1, and Fig. 3 is a side view of the position detection device shown in Fig. 1. 4 are detailed views of the position detection device shown in FIG. 3, and FIG. 5 is an explanatory diagram of the operation of the position detection device shown in FIG. 3. 7...Arm, 12...Air operated cylinder, 18...Coil spring.

Claims (1)

[Claims] 1 A position detection device that detects the position of a workpiece transported by a transport device in a direction perpendicular to the transport direction, which includes a base and a base rotatably supported at one end. a cylinder having one end rotatably supported by the arm and the other end rotatably supported by the base so that the other end of the arm can approach and move away from the workpiece; a spring member having one end attached to the arm and the other end attached to the base so as to be able to press the other end of the arm against the workpiece; a detector for detecting the amount of rotation of the cylinder with respect to the base when the side approaches the workpiece by a predetermined distance and the cylinder can rotate integrally with the arm; Work body position detection device.