JP7191575B2 - industrial robot - Google Patents

Description

The present invention relates to an industrial robot that transports objects such as semiconductor wafers.

The robot described in Patent Document 1 is a robot that transports a semiconductor wafer. A hand (end effector) on which the semiconductor wafer is placed has magnetic wafer support pins and an elastic body that supports the wafer support pins on the surface of the hand (end effector). , and a magnetic sensor adjacent to the elastic body. The weight of the semiconductor wafer compresses the elastic body interposed between the wafer support pin and the magnetic sensor, shrinks the gap between the wafer support pin and the magnetic sensor, and changes the output of the magnetic sensor. The presence or absence of the semiconductor wafer on the hand is detected based on the change in the output of this magnetic sensor.

JP 2005-268556 A

The transfer robot described in Patent Document 1 merely detects the presence or absence of a semiconductor wafer on the hand. The semiconductor wafer is simply placed on the hand and is not fixed on the hand. From the viewpoint of protecting the surface of the semiconductor wafer, the semiconductor wafer is supported by a plurality of wafer support pins, including magnetic wafer support pins, with a gap between it and the mounting surface of the hand, and is unstable. . If the semiconductor wafer is not properly placed on the hand, the semiconductor wafer may drop from the hand due to vibration or collision with an obstacle during transportation, and the semiconductor wafer may be damaged.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an industrial robot capable of detecting the placement state of an object to be transported.

An industrial robot according to one aspect of the present invention is an industrial robot that transports a plate-shaped object to be transported, wherein a hand on which the transport object is placed and the transport object on the hand are detected. and a detection unit, wherein the hand moves the object to be conveyed so that the object to be conveyed is arranged along the mounting surface with a gap between it and the object to be conveyed. and a first support portion, a second support portion, and a third support portion capable of supporting the three portions of and a plurality of reflective optical sensors disposed facing the outer peripheral surface of the object to be conveyed supported by and based on output signals of the plurality of reflective optical sensors, the placement state of the object to be conveyed is determined. and a signal processing unit for determining, the plurality of reflective optical sensors are arranged on one side of a center line that passes through the first support and between the second support and the third support. a first sensor provided on the other side and a second sensor provided on the other side, wherein the signal processing unit determines whether both the output signal value of the first sensor and the output signal value of the second sensor is equal to or greater than the threshold value, it is determined that the placement state of the object to be conveyed is appropriate.

ADVANTAGE OF THE INVENTION According to this invention, the industrial robot which can detect the mounting state of the conveyance target object can be provided.

1 is a plan view of an example of an industrial robot for describing an embodiment of the present invention, and is a plan view of a state in which an arm is retracted; FIG. FIG. 2 is a plan view of the industrial robot of FIG. 1, showing a state in which an arm is extended; 2 is a front view of the industrial robot of FIG. 1; FIG. FIG. 2 is a plan view of a hand of the industrial robot of FIG. 1; FIG. 5 is a cross-sectional view taken along line VV of FIG. 4; It is a schematic diagram of an example of the mounting state of the conveyance target object. 7 is a cross-sectional view taken along line VII-VII of FIG. 6; FIG. FIG. 10 is a schematic diagram of another example of a placement state of an object to be transported; FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. 8; FIG. 10 is a schematic diagram of another example of a placement state of an object to be transported; 11 is a cross-sectional view along line XI-XI of FIG. 10; FIG. FIG. 10 is a schematic diagram of another example of a placement state of an object to be transported;

(Overall configuration of industrial robot)
1 to 3 show an example of an industrial robot for describing embodiments of the present invention. An industrial robot 1 (hereinafter referred to as "robot 1") is a robot for transporting a semiconductor wafer 2 (hereinafter referred to as "wafer 2") which is a plate-shaped object to be transported. The robot 1, for example, simultaneously unloads a plurality of wafers 2 from a cassette (not shown) in which a plurality of wafers 2 are stacked and stored at a predetermined pitch. Then, the robot 1 loads the plurality of wafers 2 carried out from the cassette into a heating furnace (not shown) of the semiconductor manufacturing system in which the plurality of wafers 2 are stacked and stored at a predetermined pitch. Further, the robot 1 simultaneously unloads a plurality of wafers 2 from the heating furnace and loads the unloaded wafers 2 into the cassette.

The robot 1 includes a wafer loading mechanism 3 on which a plurality of wafers 2 are loaded, a first arm 4 that rotatably supports the base end side of the wafer loading mechanism 3, and storage of the wafers 2 in a cassette or a heating furnace. A sensing hand 5 for detecting a state, a second arm 6 rotatably supporting the proximal side of the sensing hand 5, and rotatable proximal sides of the first arm 4 and the second arm 6. and an elevating mechanism 8 that supports the arm supporting part 7 so as to be able to move up and down.

The wafer mounting mechanism 3 has a plurality of transfer hands that are arranged so as to overlap vertically at a predetermined pitch. The pitch of the wafers 2 stored in the cassette may be different from the pitch of the wafers 2 stored in the heating furnace. good.

The sensing hand 5 is for detecting the housing state (inclination, protrusion, etc.) of the wafer 2 in the cassette or in the heating furnace before the wafer 2 is unloaded from the cassette or the like. The sensing hand 5 is vertically moved integrally with the arm support portion 7 , and the wafer 2 is placed on the sensing hand 5 according to the vertical movement of the sensing hand 5 . The wafer 2 placed on the sensing hand 5 may be transferred between the cassette and the heating furnace by the sensing hand 5 .

The first arm 4 and the second arm 6 have two joints and are configured to expand and contract as a whole. The base end side of the first arm 4 and the base end side of the second arm 6 are supported by an arm support portion 7 and expand and contract individually. The arm support section 7 has a first support section 9 that supports the first arm 4 and the second arm 6 and a second support section 10 that supports the first support section 9 . A turning mechanism for rotating the first support portion 9 is housed inside the second support portion 10, and the first support portion 9 is rotatably supported by the second support portion 10. .

The elevating mechanism 8 is configured using, for example, a linear motion guide including a feed screw shaft arranged to extend in the vertical direction and a strut supporting the feed screw shaft. A nut member is provided that threads onto the shaft. The feed screw shaft is rotated by the motor, and the second support portion 10 is vertically moved along the feed screw shaft according to the rotation of the feed screw shaft. Thereby, the arm support part 7 is raised and lowered.

(Structure of sensing hand)
4 and 5 show the configuration of the sensing hand 5. FIG. The sensing hand 5 includes a base end portion 51 rotatably supported by the second arm 6, and a first arm portion 52 and a second arm portion 53 bifurcated from the base end portion 51 toward the tip side. and has a Y shape as a whole. The sensing hand 5 has a mounting surface 54 facing the rear surface 21 of the wafer 2 mounted on the sensing hand 5 .

A first support portion 55 is provided on the mounting surface 54 of the base end portion 51 , and a second support portion 56 is provided on the mounting surface 54 at the tip of the first arm portion 52 . A third support portion 57 is provided on the mounting surface 54 at the tip of the portion 53 . The first support portion 55 , the second support portion 56 and the third support portion 57 support the wafer 2 so that the wafer 2 is arranged along the mounting surface 54 with a gap between the wafer 2 and the mounting surface 54 . Three points on the back surface 21 can be supported.

In this example, the first support portion 55, the second support portion 56, and the third support portion 57 are triangular regions obtained by connecting the first support portion 55, the second support portion 56, and the third support portion 57. Each has an inclined surface 58 directed to the center O of the circumscribed circle of R, and each inclined surface 58 is inclined so as to approach the center O as it approaches the mounting surface 54 . When the wafer 2 is properly placed, the edge 21e of the outer peripheral portion of the back surface 21 of the wafer 2 is in contact with the inclined surfaces 58 of the first support portion 55, the second support portion 56, and the third support portion 57, respectively. , supported by these sloping surfaces 58 .

The outer peripheral portion of the back surface 21 of the wafer 2 is supported by the first support portion 55, the second support portion 56, and the third support portion 57, so that the central portion of the back surface 21 of the wafer 2 is supported by the mounting surface 54 and the third support portion. It is not in contact with the first supporting portion 55, the second supporting portion 56, and the third supporting portion 57, and is protected from damage and contamination due to contact with the mounting surface 54 and the like. A plurality of semiconductor devices will be formed in the central portion of the wafer 2 later, and by keeping the central portion of the back surface 21 clean, desired characteristics of the semiconductor devices, for example, can be obtained.

Furthermore, the edge 21e of the outer peripheral portion of the back surface 21 of the wafer 2 is supported by the inclined surfaces 58 of the first support portion 55, the second support portion 56, and the third support portion 57, respectively, so that the mounting surface of the wafer 2 is Movement along 54 is inhibited. As a result, the wafer 2 may come off from one or more of the first support portion 55, the second support portion 56, and the third support portion 57 due to vibrations or the like during transportation, or the wafer 2 may be removed from the sensing portion. Dropping from the hand 5 is suppressed. Further, even if the wafer 2 is in contact with the inclined surfaces 58 of the first supporting portion 55, the second supporting portion 56, and the third supporting portion 57 in a slightly inclined state with respect to the mounting surface 54, for example, during transfer, The wafer 2 can be arranged substantially parallel to the mounting surface 54 by vibration or the like.

As long as the center of gravity of the wafer 2 is arranged within the triangular region R obtained by connecting the first support portion 55, the second support portion 56, and the third support portion 57, the first support portion 55, the Although the positions of the second support part 56 and the third support part 57 are not limited, considering that the circular wafer 2 is symmetrical with respect to an arbitrary diameter, the second support part 56 and the third support part 57 are preferably The three support portions 57 are arranged symmetrically with respect to a center line C connecting the center O of the circumscribed circle of the triangular region R and the first support portion 55 . Thereby, the wafer 2 can be stably supported.

The sensing hand 5 further has a detection unit 60 that detects the wafer 2 on the sensing hand 5. The detection unit 60 includes a first sensor 61 and a second sensor 62, which are reflective optical sensors, and a first sensor. 61 and a signal processing unit 63 for determining the placement state of the wafer 2 based on the output signals of the second sensor 62 . Here, the reflective optical sensor includes a light-emitting element and a light-receiving element, reflects light emitted from the light-emitting element by an object, detects the reflected light with the light-receiving element, and detects the intensity of the reflected light. output a signal. The signal value of the output signal is basically related to the distance between the light-emitting element and the light-receiving element and the reflecting surface of the object, and the greater the distance, the smaller the signal value. The signal value is also related to the incident angle of the light with respect to the reflecting surface of the object, and the signal value decreases as the incident angle increases.

When the wafer 2 is properly placed, that is, the edge 21 e of the outer peripheral portion of the back surface 21 of the wafer 2 is supported by the inclined surfaces 58 of the first support portion 55 , the second support portion 56 and the third support portion 57 . In this state, the first sensor 61 and the second sensor 62 face the outer peripheral surface 22 of the wafer 2 , and the light emitted from the light emitting elements of the first sensor 61 and the second sensor 62 respectively reaches the outer peripheral surface 22 of the wafer 2 . , and the reflected light is detected by the light receiving elements of the first sensor 61 and the second sensor 62 .

The first sensor 61 is provided on one side of the center line C, and the second sensor 62 is provided on the other side of the center line C. As shown in FIG. As a result, the deviation from the position of the wafer 2 when the wafer 2 is properly mounted can be determined in the first direction X parallel to the center line C and in the first direction X parallel to the mounting surface 54 and perpendicular to the center line C. Detection is possible in two directions, ie, two Y directions. Considering that the circular wafer 2 is symmetrical with respect to an arbitrary diameter, the first sensor 61 and the second sensor 62 are preferably arranged symmetrically with respect to the center line C, For example, as shown in FIG. 4, they are provided adjacent to both sides of the first support portion 55 extending symmetrically on both sides of the center line C. As shown in FIG.

(Determination example 1 of the signal processing unit 63)
Output signals from the first sensor 61 and the second sensor 62 are input to the signal processing unit 63 . Then, the signal processing unit 63 determines whether or not the mounting state of the wafer 2 on the sensing hand 5 is appropriate based on the two signals that are input. Determination can be made using a threshold. It is possible to determine that the placement state of the wafer 2 is appropriate, and that the placement state of the wafer 2 is inappropriate if the signal value of at least one of the output signals is less than the threshold value. The threshold value can be appropriately set based on the output signal value when the mounting state of the wafer 2 is proper and the output signal value when the mounting state of the wafer 2 is improper.

6 and 7 show an example in which the wafer 2 is properly placed. Both the first sensor 61 and the second sensor 62 face the outer peripheral surface 22 of the wafer 2, and the light L from the first sensor 61 and the light from the second sensor 62 are extremely small incident on the outer peripheral surface 22. Incident at an angle. Moreover, both the distance between the first sensor 61 and the outer peripheral surface 22 and the distance between the second sensor 62 and the outer peripheral surface 22 are sufficiently small. In this case, the signal values of both the output signal of the first sensor 61 and the output signal of the second sensor 62 are equal to or greater than the threshold. Therefore, the signal processing unit 63 determines that the mounting state of the wafer 2 is proper.

8 and 9 show an example in which the mounting state of the wafer 2 is inappropriate. In the examples shown in FIGS. 8 and 9, the wafer 2 is displaced along the first direction X toward the tip side of the sensing hand 5 . The wafer 2 rides on the second support portion 56 and the third support portion 57 on the front end side, and is separated from the first support portion 55 on the base end side and is in contact with the mounting surface 54 . In this case, the first sensor 61 and the second sensor 62 both deviate from the outer peripheral surface 22 of the wafer 2 and face the surface 23, and the light L from the first sensor 61 and the light from the second sensor 62 are Both are incident on the surface 23 at an angle larger than the angle of incidence on the outer peripheral surface 22 shown in FIG. Also, the distance between the first sensor 61 and the surface 23 is greater than the distance between the first sensor 61 and the outer peripheral surface 22 shown in FIG. 6, and the distance between the second sensor 62 and the surface 23 is also , is greater than the distance between the second sensor 62 and the outer peripheral surface 22 shown in FIG. Therefore, the signal values of both the output signal of the first sensor 61 and the output signal of the second sensor 62 are less than the threshold. Therefore, the signal processing unit 63 determines that the placement state of the wafer 2 is inappropriate.

10 and 11 show another example in which the mounting state of the wafer 2 is inappropriate. In the example shown in FIGS. 10 and 11, the wafer 2 is shifted along the first direction X toward the base end side of the sensing hand 5 . The wafer 2 rides on the first support portion 55 on the base end side, and is separated from the second support portion 56 and the third support portion 57 on the front end side and is in contact with the mounting surface 54 . In this case, the first sensor 61 and the second sensor 62 both deviate from the outer peripheral surface 22 of the wafer 2 and face the rear surface 21, and the light from the first sensor 61 and the light from the second sensor 62 are is also incident on the rear surface 21 at an angle larger than the incident angle with respect to the outer peripheral surface 22 shown in FIG. Also, the distance between the first sensor 61 and the back surface 21 is greater than the distance between the first sensor 61 and the outer peripheral surface 22 shown in FIG. 6, and the distance between the second sensor 62 and the back surface 21 is also , is greater than the distance between the second sensor 62 and the outer peripheral surface 22 shown in FIG. Therefore, the signal values of both the output signal of the first sensor 61 and the output signal of the second sensor 62 are less than the threshold. Therefore, the signal processing unit 63 determines that the placement state of the wafer 2 is inappropriate.

FIG. 12 shows another example in which the mounting state of the wafer 2 is inappropriate. In the example shown in FIG. 12, the wafer 2 is shifted along the second direction Y toward the second support portion 56 side of the center line C. In the example shown in FIG. The wafer 2 rides on the second support portion 56 on the front end side, is separated from the third support portion 57 and is in contact with the mounting surface 54 , but is in contact with the inclined surface 58 of the first support portion 55 on the base end side. there is The inclination of the wafer 2 with respect to the mounting surface 54 is smaller than the inclination of the wafer 2 shown in FIGS. 6 and 7 and the inclination of the wafer 2 shown in FIGS. The first sensor 61 and the second sensor 62 adjacent to each other are both opposed to the outer peripheral surface 22 of the wafer 2 . The distance between the first sensor 61 on the second support portion 56 side of the center line C and the outer peripheral surface 22 of the wafer 2 is the distance between the first sensor 61 and the outer peripheral surface 22 shown in FIG. , and the signal value of the output signal of the first sensor 61 is equal to or greater than the threshold. However, the distance between the second sensor 62 on the third support portion 57 side of the center line C and the outer peripheral surface 22 of the wafer 2 is the distance between the second sensor 62 and the outer peripheral surface 22 shown in FIG. , and the signal value of the output signal of the second sensor 62 is less than the threshold. According to the determination example described above, the signal processing unit 63 determines that the mounting state of the wafer 2 is inappropriate.

When it is determined that the mounting state of the wafer 2 on the sensing hand 5 is appropriate, the robot 1 extends the first arm 4, raises and lowers the arm support section 7, and removes the wafer 2 from the cassette or the like by the wafer mounting mechanism 3. The wafer 2 is unloaded. On the other hand, when it is determined that the placement state of the wafer 2 on the sensing hand 5 is inappropriate, the robot 1 stops operating, for example.

By arranging the first sensor 61 and the second sensor 62, which are reflective photosensors, so as to face the outer peripheral surface of the wafer 2 in this way, for example, the mounted state shown in FIGS. 11, the tilted state of the wafer 2 can be detected when the wafer 2 rides on one or two supports. By arranging the first sensor 61 and the second sensor 62 on both sides of the center line C, it is possible to prevent the wafer 2 from being displaced to one side of the center line C, as shown in FIG. detectable. By detecting the mounting state of the wafer 2 in this way, it is possible to prevent the wafer 2 from being transported in an inappropriate mounting state, and to prevent the wafer 2 from falling and being damaged due to the falling.

Preferably, the first sensor 61 and the second sensor 62 are provided at mutually symmetrical positions with the center line C interposed therebetween. As a result, the mounting state of the wafer 2 can be equally detected regardless of which side of the center line C the wafer 2 is displaced from. Also, preferably, the first sensor 61 and the second sensor 62 are provided adjacent to both sides of the first support portion 55 . As a result, the state in which the wafer 2 is tilted due to riding on one or two support portions including the first support portion 55 or coming off the one or two support portions including the first support portion 55 can be reliably detected. be able to.

(Determination example 2 of the signal processing unit 63)
The determination of the mounting state of the wafer 2 performed by the signal processing unit 63 is not limited to the example described above. For example, when the signal value of at least one of the output signal of the first sensor 61 and the output signal of the second sensor 62 is equal to or greater than a threshold value, it is determined that the placement state of the wafer 2 is appropriate. The placement state of the wafer 2 may be determined to be inappropriate when the signal value of the output signal is less than the threshold. According to this example, the mounting state of the wafer 2 having a relatively small inclination with respect to the mounting surface 54 shown in FIG. 12 is determined to be appropriate. In this way, it is possible to widen the range of wafer 2 placement states that are deemed appropriate, which is useful, for example, when the robot 1 frequently stops its operation.

Further, a determination pattern for determining that the placement state of the wafer 2 is inappropriate when the signal value of at least one of the output signal of the first sensor 61 and the output signal of the second sensor 62 is less than a threshold value. As the first determination pattern, when the signal value of at least one of the output signal of the first sensor 61 and the output signal of the second sensor 62 is equal to or greater than the threshold value, it is determined that the mounting state of the wafer 2 is proper. The signal processing unit 63 may be configured to be selectively set to the first determination pattern or the second determination pattern by, for example, switch operation, with the determination pattern used as the second determination pattern. As a result, the appropriate placement state can be changed according to the user's request, and the convenience of the robot 1 can be improved.

As described above, the industrial robot disclosed in the present specification is an industrial robot that transports a plate-shaped object to be transported, and includes a hand on which the transport object is placed and a and a detection unit for detecting the object to be conveyed, wherein the hand is arranged along the mounting surface with a gap between the mounting surface and the mounting surface where the object to be conveyed is placed. , a first supporting portion, a second supporting portion, and a third supporting portion capable of supporting three points on the back surface of the object to be conveyed, and the detecting portion includes the first supporting portion and the third supporting portion. a plurality of reflective optical sensors arranged facing the outer peripheral surface of the object to be conveyed supported by the second supporting portion and the third supporting portion; and based on the output signals of the plurality of reflective optical sensors, and a signal processing unit that determines a placement state of the transport object, wherein the plurality of reflective optical sensors pass through the first support and extend between the second support and the third support. A first sensor provided on one side of a center line passing through the middle, and a second sensor provided on the other side, wherein the signal processing unit receives the output signal value of the first sensor and the second sensor is equal to or greater than a predetermined threshold value, it is determined that the placement state of the object to be conveyed is appropriate. According to this configuration, the object to be conveyed rides on one or two supporting portions (disengages from one or two supporting portions) by the reflective optical sensor arranged so as to face the outer peripheral surface of the object to be conveyed. tilted state can be detected. In addition, the reflective optical sensors arranged on both sides of the center line can detect the state in which the object to be conveyed is deviated from the center line in the direction orthogonal to the center line. Then, when both the signal values of the output signal value of the first sensor and the output signal value of the second sensor are equal to or greater than a predetermined threshold value, the placement state of the object to be conveyed (tilt and center with respect to the placement surface) deviation from the line) can be determined as appropriate.

Further, in the industrial robot disclosed in the present specification, the signal processing unit detects when at least one of the output signal value of the first sensor and the output signal value of the second sensor is less than the threshold value , the placement state of the transport object is determined to be inappropriate. According to this configuration, the proper placement state can be determined severely.

Further, in the industrial robot disclosed in the present specification, the signal processing unit performs the determining that the placement state of the object to be conveyed is appropriate, and when both the output signal value of the first sensor and the output signal value of the second sensor are less than the threshold value, the object to be conveyed is The placement state is determined to be inappropriate. With this configuration, it is possible to widen the range of placement states that are considered appropriate.

Further, in the industrial robot disclosed in the present specification, the signal processing unit detects when at least one of the output signal value of the first sensor and the output signal value of the second sensor is less than the threshold value , when at least one of a first determination pattern for determining that the placement state of the conveying object is inappropriate, an output signal value of the first sensor, and an output signal value of the second sensor is equal to or greater than the threshold; determining that the placement state of the object to be conveyed is appropriate, and when both the output signal value of the first sensor and the output signal value of the second sensor are less than the threshold value, the object to be conveyed is and a second determination pattern for determining that the placement state is inappropriate, and can be selectively set to the first determination pattern or the second determination pattern. According to this configuration, the placement state considered appropriate can be changed according to the user's request, and the convenience of the robot 1 can be enhanced.

Further, the industrial robot disclosed in this specification stops operation when the signal processing unit determines that the placement state of the object to be transported is inappropriate. According to this configuration, it is possible to prevent the object to be conveyed from being conveyed in an inappropriately placed state, and to prevent the object to be conveyed from falling or being damaged due to the falling.

Further, in the industrial robot disclosed in this specification, the first sensor and the second sensor are provided at mutually symmetrical positions with respect to the center line. According to this configuration, it is possible to equally detect the placed state regardless of whether the object to be conveyed is shifted to either side with respect to the center line.

Further, in the industrial robot disclosed in this specification, the first sensor and the second sensor are provided adjacent to the first support section. According to this configuration, the object to be conveyed can be reliably kept in an inclined state by riding on one or two supporting parts including the first supporting part or coming off the one or two supporting parts including the first supporting part. detectable.

Further, in the industrial robot disclosed in this specification, the first supporting portion, the second supporting portion, and the third supporting portion support the outer peripheral portion of the back surface of the object to be conveyed. According to this configuration, the back surface of the object to be conveyed can be protected.

Further, in the industrial robot disclosed in this specification, the first support portion, the second support portion, and the third support portion are configured as the first support portion, the second support portion, and the third support portion. and the circumscribed circle of the triangular area obtained by connecting . contacts the edge of the outer periphery of the back surface of the According to this configuration, it is possible to suppress displacement of the object to be conveyed due to vibration or the like that accompanies transportation. Also, if the deviation is slight, it can be automatically returned to the proper position by the inclined surface.

Further, the industrial robot disclosed in this specification conveys a semiconductor wafer as the object to be conveyed.

1 industrial robot 2 semiconductor wafer (transport object)
3 Wafer mounting mechanism 4 First arm 5 Sensing hand 6 Second arm 7 Arm supporting part 8 Elevating mechanism 9 First supporting part 10 Second supporting part 21 Back surface 21e of wafer Edge 22 of the outer peripheral portion on the back surface of the wafer Outer periphery of the wafer Surface 23 Wafer surface 51 Sensing hand base end 52 Sensing hand first arm 53 Sensing hand second arm 54 Sensing hand mounting surface 55 First support 56 Second support 57 Third support portion 58 Inclined surface 60 Detection portion 61 First sensor (reflective optical sensor)
62 second sensor (reflective optical sensor)
63 Signal processing unit C Center line O Center L Light R Triangular region X First direction Y Second direction

Claims (4)

An industrial robot that transports a plate-shaped object to be transported,
a hand on which the object to be conveyed is placed;
a detection unit that detects the object to be conveyed on the hand;
with
The hand is
a mounting surface;
a first supporting portion capable of supporting three points on the back surface of the object to be conveyed so that the object to be conveyed is disposed along the mounting surface with a gap between the object to be conveyed and the mounting surface; a support and a third support;
has
The detection unit is
a plurality of reflective optical sensors disposed facing the outer peripheral surface of the object to be conveyed supported by the first support portion, the second support portion, and the third support portion;
a signal processing unit that determines a placement state of the object to be transported based on the output signals of the plurality of reflective optical sensors;
has
The plurality of reflective optical sensors include a first sensor provided on one side of a center line passing through the first support section and between the second support section and the third support section; a second sensor provided;
The signal processing unit is
determining that the placement state of the object to be transported is appropriate when both the output signal value of the first sensor and the output signal value of the second sensor are equal to or greater than a predetermined threshold ;
a first determination pattern for determining that the placement state of the conveying object is inappropriate when at least one of the output signal value of the first sensor and the output signal value of the second sensor is less than the threshold value;
When at least one of the output signal value of the first sensor and the output signal value of the second sensor is equal to or greater than the threshold value, it is determined that the placement state of the conveying object is appropriate, and the a second determination pattern for determining that the placement state of the conveying object is inappropriate when both the output signal value and the output signal value of the second sensor are less than the threshold value;
and can be selectively set to the first determination pattern or the second determination pattern . The industrial robot according to claim 1,
The signal processing unit determines that the placement state of the conveying object is inappropriate when at least one of the output signal value of the first sensor and the output signal value of the second sensor is less than the threshold value. industrial robot. The industrial robot according to claim 1,
The signal processing unit is
determining that the placement state of the object to be transported is appropriate when at least one of the output signal value of the first sensor and the output signal value of the second sensor is equal to or greater than the threshold;
An industrial robot that determines that the placement state of the transport object is inappropriate when both the output signal value of the first sensor and the output signal value of the second sensor are less than the threshold value. The industrial robot according to any one of claims 1 to 3,
An industrial robot that stops operating when the signal processing unit determines that the placement state of the object to be transported is inappropriate.

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