JP2021022643A - Method for detecting work position in robot - Google Patents

Abstract

To eliminate the overlap of a workpiece without a large movement of a hand, and detect an edge position of the workpiece by an edge detection sensor such as a light blocking sensor in a robot having a plurality of hands.SOLUTION: Hands 13A and 13B are made to be able to move forward and backward along a first direction while keeping their orientation fixed in the first direction. For each of the hands 13A and 13B, a mechanism that can rotate in a direction deviating from the first direction is provided around wrist shafts 34A and 34B connecting an articulated mechanism and the hand. A workpiece 50A is retracted from a detection space of an edge detection sensor 28 by rotating the hand 13A holding the workpiece 50A that is not a detection target around its wrist axis 34A, and the position of the side of a workpiece 40B being the detection target is detected.SELECTED DRAWING: Figure 3

Description

The present invention relates to a robot used for transporting a plate-shaped work such as a glass substrate for a liquid crystal display panel, and more particularly to a method of detecting the position of the work on the hand of the robot.

In a liquid crystal display device manufacturing line or the like, a robot is used to transfer a work such as a substrate between different processing devices. In that case, when transporting the work, the robot's hand is inserted into the load lock chamber or cassette of the processing device that is the carry-in source, the work is held on the hand, and the hand on which the work is placed is placed from the load lock chamber or the like. Pull out, move the robot arm or the entire robot with the work on the hand, then insert the hand into the load lock chamber of the processing device to be carried in, store the work in the load lock chamber, and then only the hand Is done by pulling out of the load lock room. The hand has, for example, a fork-like shape. The robot has, for example, a horizontal articulated mechanism configured by connecting two arms and having a hand at the tip, an elevating mechanism that raises and lowers the hand together with the horizontal articulated mechanism in the vertical direction, and a vertical axis as a rotation axis. It is provided with a rotation mechanism that rotates the entire horizontal articulated mechanism in a horizontal plane. The horizontal articulated mechanism moves the hand forward or backward on the same straight line by reducing or increasing the angle formed by the two arms. In order to change the direction in which the hand moves in the horizontal plane, it is necessary to rotate the entire horizontal articulated mechanism by the rotation mechanism. Further, a transport mechanism for linearly moving the entire robot in a horizontal plane is provided. An example of such a robot is described in Patent Document 1. In the following description, the forward and backward directions of the hand are referred to as the front-back direction, and the direction orthogonal to the front-back direction is referred to as the left-right direction.

If the work is not placed in the designated position on the hand, an error may occur when storing the work in the load lock chamber which is the transfer destination. In the case of a rectangular work, it is generally considered that the designated position is a state in which the four sides of the work are aligned with respect to the front-back direction and the left-right direction of the hand at a predetermined position on the hand. In the following description, the side of the work that should be parallel to the front-back direction of the hand is called the vertical side of the work, and the side that should be parallel to the left-right direction of the hand is called the horizontal side of the work. The deviation of the work from the specified position on the hand is the deviation from the specified position in the front-back direction of the hand, the deviation from the specified position in the left-right direction of the hand, and the lateral side of the work and the left-right direction of the hand. There are three possible deviations in the angle of formation. The angle formed by the lateral side of the work and the left-right direction of the hand is called an inclination angle, and the inclination angle is 0 when the work is in a designated position. Of these, the deviation and the inclination angle in the front-rear direction can be compensated by providing the hand with a sensor for detecting the lateral side of the work. When the work is in the reference position, sensors for detecting the work are placed at two positions on the hand that extend in the left-right direction of the work, that is, the positions corresponding to the horizontal sides, and these sensors are simultaneously placed on the horizontal sides. If the forward or backward amount of the hand and the turning amount of turning the hand together with the horizontal articulated mechanism are controlled so as to detect, the work is placed on the hand so as not to cause a displacement and an inclination angle in the front-rear direction. be able to. Alternatively, the amount of deviation can be obtained, and compensation can be performed based on the amount of deviation when the work is conveyed to the load lock chamber at the transfer destination.

However, in the general case where the lateral side of the work is longer than the horizontal length of the hand, the sensor provided in the hand may detect the vertical side of the work. Since it cannot be done, the amount of deviation cannot be obtained, and this deviation cannot be compensated. Therefore, in Patent Document 2, an edge detection sensor is attached at a position that is not affected by the operation of the horizontal articulated mechanism, for example, an edge detection sensor is attached so as to be fixed to the elevating mechanism, and the position of the vertical side of the work. Is disclosed by this edge detection sensor. As the edge detection sensor, a line sensor or the like, which is a light-shielding one-dimensional position sensor, can be used. The deviation of the mounting position of the work in the hand in the left-right direction can be compensated by adjusting the amount of movement of the robot by the transport mechanism based on the detection result by the edge detection sensor. Further, in order to further improve the transfer efficiency of the work, Patent Document 2 discloses a robot in which two sets of horizontally articulated mechanisms that are independently controlled and a hand is attached to each of the horizontal articulated mechanisms. The robot is configured so that the forward and backward directions of the two hands are the same as each other, and the two hands can be positioned so as to accurately overlap each other in the vertical direction. The distance between the hands in the vertical direction is narrow, and the horizontal edge of the work held on the hand is detected by one line sensor provided as common to the two hands.

Japanese Unexamined Patent Publication No. 2003-117862 Japanese Unexamined Patent Publication No. 2008-30241

In a robot having two or more horizontal articulated mechanisms each equipped with a hand and used for transporting a work, when an edge detection sensor for detecting the position of the edge of the work, that is, the vertical side is shared between the hands, the edge If the workpieces overlap in the detection space of the detection sensor, the edge of the workpiece cannot be detected. In order to detect the position of the work in the left-right direction on the hand, there must be no work other than the work to be detected in the detection space of the edge detection sensor. Therefore, when two or more hands each hold a work, the work other than the work to be detected is moved so that the work other than the work to be detected does not exist in the detection space of the edge detection sensor. Need arises. However, it takes time to move the hand to move the work, and depending on the position of the robot, it may not be possible to move the work by advancing the hand due to interference from the wall surface around the robot. It can happen. When it is not possible to move the hand forward due to the position of the robot, it is possible to move the robot to a wider space or change the direction of the hand together with the horizontal articulated mechanism, but in order to make such an operation Also takes time.

An object of the present invention is to provide a work position detection method capable of detecting the edge position of a work by eliminating the overlap of the works without a large movement of the hands in a robot having a plurality of hands.

The work position detection method of the present invention is a work position detection method in a robot that has a plurality of hands and can place a work for each hand, and the robot is provided for each hand and the main body of the robot. An articulated mechanism that can move the hand forward and backward along the first direction while fixing the direction of the hand in the first direction, and an edge detection sensor that is commonly attached to the main body of multiple hands. By driving an articulated mechanism, a plurality of hands can be positioned so as to overlap in the vertical direction, and an edge detection sensor is provided when the plurality of hands move in the first direction. It has a detection space so as to include an area through which the work mounted on the hand passes, and is configured to detect the position of the side of the work in the second direction orthogonal to the first direction in the detection space. The robot is further equipped with a mechanism for rotating the hand in a direction deviating from the first direction around the wrist axis connecting the articulated mechanism and the hand for each hand, and the position of the side in the second direction. By rotating the hand holding the work that is not the target of detection around the wrist axis of the hand by the mechanism, the work that is not the target of detection is ejected from the detection space, and the position of the side is detected. It has a step of detecting the position of the side of the work piece by the edge detection sensor.

According to the work position detection method of the present invention, the overlap of the works can be eliminated only by rotating the hand around the wrist axis, and the side of the work to be detected can be detected by the edge detection sensor, so that the hand can be advanced. It is possible to reduce the time required to do this.

In the work position detection method of the present invention, it is preferable that the edge detection sensor is attached to the main body so as to detect the position of the side of the work placed on the hand in the retracted position. Since the hand in the retracted position is the most resistant to interference from the wall surface around the robot, according to this configuration, the space that must be provided around the robot to eliminate the overlap of the workpieces is reduced. Because it can be installed, the robot can be installed in a small space.

In the work position detection method of the present invention, each of the plurality of hands is provided with a pair of sensors provided apart from each other along the second direction, and the hand is directed toward the work in order to place the work on the hand. When moving forward, a pair of sensors is used to determine the tilt angle of the work with respect to the hand, and the hand is rotated around the wrist axis according to the tilt angle so that the tilt angle becomes 0. Can be placed in. By placing the work on the hand in this way, it is possible to simplify the calculation of the amount of movement of the robot when the placed work is conveyed to the transfer destination.

Alternatively, in the work position detection method of the present invention, each of the plurality of hands is provided with a pair of sensors provided apart from each other along the second direction, and the hands are placed toward the work in order to place the work on the hand. When advancing, a pair of sensors may be used to determine the tilt angle of the work with respect to the hand, and the tilt angle may be stored and the work may be placed on the hand. In this case, since the hand angle is not corrected based on the inclination angle, the time can be shortened by that amount.

In the work position detection method of the present invention, the articulated mechanism for each hand is attached to the main body on a common axis, and then the position of the common axis as viewed from the wrist axis of the hand when retracting along the first direction. It is preferable to attach the edge detection sensor to the main body at a position in the forward direction. According to this configuration, the edge detection sensor can detect the side of the work when the hand is in the retracted position, and the wrist axis and the edge detection sensor can be sufficiently separated from each other to detect the hand of the work that is not the detection target. The angle of rotation can be reduced when the is rotated around the wrist axis.

According to the present invention, in a robot having a plurality of hands, it is possible to eliminate the overlap of the workpieces and detect the edge position of the workpieces without accompanied by a large movement of the hands.

(A) and (b) are side views and plan views of the robot according to the embodiment of the present invention, respectively. It is a side view which shows the robot in the state which the horizontal articulated mechanism is raised. It is a figure explaining the movement of the hand of a robot.

Next, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a robot according to an embodiment of the present invention, and FIGS. 1A and 1B are side views and plan views, respectively. The robot shown in FIG. 1 is a horizontal articulated robot that conveys a substantially rectangular plate-shaped work 50 such as a glass substrate used for manufacturing a liquid crystal display panel, and two hands 13A and 13B for holding the work 50, respectively. It is a so-called double-handed robot equipped with. Further, FIG. 2 shows a state in which the horizontal articulated mechanism is raised in the robot shown in FIG.

The robot has a base 22 that can move on a pair of rails 21 that are parallel to each other and are provided in a straight line on the floor surface, and a motor that is provided on the base 22 and built in the base 22 (not shown). ), A turntable 23 that rotates in a horizontal plane around the rotary shaft 31 and an elevating mechanism 24 that is provided so as to stand upright with respect to the turntable 23. A cover 25 for covering the rail 21 is attached to the rail 21. The elevating mechanism 24 includes a fixed portion 24A attached to the turntable 23 and a moving portion 24B that elevates and elevates the fixed portion 24A by a motor (not shown). FIG. 1A shows the robot of the present embodiment in a state where the moving portion 24B of the elevating mechanism 24 is located at the lowest position in the elevating range, whereas FIG. 2 shows the moving portion 24B raised. Shows the robot in the state. The moving portion 24B is provided with a support portion 26 for holding the horizontal articulated mechanism so as to extend in the horizontal direction, and two sets of horizontal articulated mechanisms are arranged and attached to the tip of the support portion 26 in the vertical direction. ing. The upper horizontal articulated mechanism is attached to the support portion 26 and can rotate in the horizontal plane around the common shaft 32, and the first arm 11A is attached to the tip of the first arm 11A and is attached in the horizontal plane around the shaft 33A. A second arm 12A capable of rotating the second arm 12A is provided, and a hand 13A is attached to the tip of the second arm 12A. Similarly, the lower horizontal articulated mechanism is attached to the support portion 26 and is attached to the tip of the first arm 11B and around the shaft 33B so that the first arm 11B can rotate in the horizontal plane around the common shaft 32. A second arm 12B that can rotate in a horizontal plane is provided, and a hand 13B is attached to the tip of the second arm 12B. The main body of the robot is the part excluding the horizontal articulated mechanism and the hands 13A and 13B attached to it.

The hands 13A and 13B have a fork-like shape in which a plurality of rod-shaped members are arranged in parallel so that the plate-shaped work 50 can be conveyed while being held in a horizontal state by holding the hands 13A and 13B from below. While holding the work 50, the hands 13A and 13B are entirely covered by the work 50 except for the root side, which is the connection position with the second arms 12A and 12B. The hands 13A and 13B are used with respect to the work 50 when the work 50 stored in the load lock chamber or the like is taken out and held on the hands 13A or 13B, or when the held work 50 is stored in the load lock chamber or the like. The forward or backward direction of the hands 13A and 13B is parallel to the extending direction of the rod-shaped member. The width of the hands 13A and 13B in the left-right direction, that is, in the direction orthogonal to the front-back direction is shorter than the width in the left-right direction of the work 50 to be conveyed.

In this robot, the horizontal articulated mechanism is a link mechanism incorporated in the first arms 11A and 11B and the second arms 12A and 12B, and the hands 13A and 13B move linearly in a direction orthogonal to the direction in which the support portion 26 extends. Is configured to perform forward and backward movements. That is, both hands 13A and 13B move forward and backward in the same direction. The movement in which the tips of the hands 13A and 13B move away from the central axis 32 is the forward movement, and the movement in the direction opposite to the forward movement is the backward movement. The first arms 11A and 11B and the second arms 12A and 12B perform bending motions as a whole, and in spite of this, the hands 13A and 13B are used to keep the directions of the hands 13A and 13B constant in the horizontal plane. They are rotatably attached in the horizontal plane around the wrist shafts 34A and 34B at the positions of the tips of the second arms 12A and 12B, respectively. In the upper horizontal articulated mechanism, the first arm 11A and the second arm 12A move by driving a motor (not shown) provided on the support portion 26, and the hand 13A supports the hand 13A while maintaining its orientation. It moves in a direction orthogonal to the extending direction of the portion 26. Similarly, in the lower horizontal articulated mechanism, the first arm 11B and the second arm 12B move by driving a motor (not shown) provided on the support portion 26, and the hand 13B keeps its orientation. As it is, it moves in a direction orthogonal to the extending direction of the support portion 26. In this robot, the hand 13A and the hand 13B can be moved independently, and the wrist shaft 34A and the wrist shaft 34B are accurately aligned in the vertical direction during these movements, that is, the hand 13A and the hand 13B Can overlap each other accurately in the vertical direction.

Each of the hands 13A and 13B includes a sensor 27 for detecting the lateral side of the work 50 which is rectangular and is located in the backward direction of the hands 13A and 13B. Sensors 27 are provided at two locations on each of the hands 13A and 13B, which are the ends in the left-right direction. By using the sensor 27, the position of the work 50 is displaced in the front-rear direction of the hands 13A and 13B. And the inclination angle formed by the lateral side of the work 50 and the left and right directions of the hands 13A and 13B can be compensated.

Further, if the robot is in a stationary position with respect to the support portion 26 to which the horizontal articulated mechanism is attached and the work 50 is held by the hands 13A and 13B, the hands 13A and 13B An edge detection sensor 28 made of, for example, a light-shielding sensor is provided at a position where the vertical side of the work 50 passes by the forward / backward movement of the work 50. In the example shown here, the edge detection sensor 28 is attached to the moving portion 24B of the elevating mechanism 24. The edge detection sensor 28 detects the deviation of the mounting position of the work 50 on the hands 13A and 13B in the left-right direction, and detects the position of the vertical side of the work 50 in the left-right direction, for example, by a one-dimensional sensor. It is configured. The edge detection sensor 28 has a U-shaped outer diameter, and uses the U-shaped opening as a detection space to detect the vertical side of the work 50 when the work 50 enters the detection space. The edge detection sensor 50 is commonly provided on the work 50 held by both hands 13A and 13B. In the robot of the present embodiment, the distance between the hands 13A and 13B in the vertical direction is constant, and the opening width of the opening of the edge detection sensor 50 is larger than the distance between the hands 13A and 13B, and both hands 13A, The work 50 can pass through when the work 50 is mounted on any of the 13Bs. Since the robot of the present embodiment is a transport robot that takes out the work 50 from the load lock chamber or the like by advancing the hands 13A and 13B and stores the work 50 in the load lock chamber, the hand 13A, When the 13B is advanced, the work 50 is separated from the detection space, and when the hands 13A and 13B are retracted, the work 50 enters the detection space.

Even if the edge detection sensor 28 is commonly provided for the work 50 mounted on each of the hands 13A and 13B, in order to detect the position of the side of the work 50, it is within the detection space of the edge detection sensor 28. It is necessary that only the work 50 to be detected exists in the detection target, and the work 50 that is not the detection target must not exist in the detection space. When both the hands 13A and 13B hold the work 50, the hand that does not hold the work 50 to be detected is moved so that only the work 50 to be detected exists in the detection space. There is a need to. Conventionally, by advancing the hand carrying the work 50 that is not the detection target, only the work 50 to be detected exists in the detection space, but it takes time to move the hand in that way. In addition, it may be difficult to move the hand in such a way in order to avoid a collision with a wall surface or the like around the robot. Therefore, in the present embodiment, as a robot, the hands 13A and 13B are moved around the wrist shafts 34A and 34B by a motor (not shown) provided for each of the hands 13A and 13B within a range of, for example, ± several degrees from the original front-rear direction. Use something that can be rotated. Then, the hand holding the work 50 other than the detection target is rotated around the wrist axis so as to deviate from the original front-rear direction. As a result, the work 50 held by the hand rotated around the wrist axis escapes from the detection space of the edge detection sensor 28, and only the work 50 to be detected can be present in the detection space. ..

FIG. 3 is a diagram schematically showing the detection of the vertical side of the work 50 by the edge detection sensor 28 in the robot of the present embodiment. A glass substrate is assumed as the work 50, and it is assumed that the other side of the work 50 can be seen through when represented in a plan view. For the sake of explanation, the work 50 held by the hands 13A and 13B will be referred to as the work 50A and 50B, respectively. (A) is a plan view showing a state in which the hands 13A and 13B are in the retracted position and overlap each other in the vertical direction, and (b) is a side view corresponding to (a). Since there are two workpieces 50A and 50B in the detection space of the edge detection sensor 28, it is not possible to detect the position of the side of any of the workpieces 50A and 50B. Here, assuming that the position of the side of the work 50B held by the lower hand 13B is detected, in the present embodiment, the upper hand 13A is moved away from the edge detection sensor 28 around the wrist shaft 34A. Rotate. As a result, the work 50A held by the upper hand 13A is out of the detection space of the edge detection sensor 28, and the edge detection sensor 28 detects the side of the work 50B held by the lower hand 13B. become able to. In FIG. 3, (c) is a plan view showing a state in which the hand 13A is rotated around the wrist shaft 34A, and (d) is a side view corresponding to (c).

On the other hand, in a conventional robot that does not rotate the hand around the wrist axis in a direction tilted from the original front-back direction, it is necessary to advance the hand holding the work 50 that is not the detection target. In the example shown in FIG. 3, in order to detect the side of the work 50B held by the lower hand 13B, it is necessary to advance the upper hand 13A. In FIG. 3, (e) is a plan view showing a state in which the upper hand 13A is advanced, and (f) is a side view corresponding to (e).

Next, the position of the edge detection sensor 28 in the robot will be described. When the horizontal articulated mechanism to which the hands 13A and 13B are attached moves up and down in the vertical direction, it is preferable that the edge of the work 50 can be detected even if the hands 13A and 13B are at a high degree. It is preferable that the edge detection sensor 28 is provided at a position where it moves up and down together with the mechanism. In the transport robot, when the entire robot is moving in parallel on a horizontal plane, the work 50 and the hands 13A and 13B are prevented from colliding with surrounding objects. 13A and 13B are in the retracted state. It is preferable that the detection of the vertical side of the work 50 is also performed when the hands 13A and 13B are in the retracted state. Further, when rotating a hand holding a work other than the detection target around the wrist axis, it is preferable that the amount of rotation is small. From the viewpoint of reducing the amount of rotation, it is preferable that the hand is attached to the edge detection sensor 28 as far as possible from the position of the wrist shaft when the hand is in the retracted state. For example, when viewed from the wrist shafts 34A and 34B of the hands 13A and 13B in the retracted state, the edge detection sensor is located at a position on the forward direction side from the position of the common shaft 32 which is the mounting position of the horizontal articulated mechanism on the support portion 26. It is preferably attached to the robot.

Next, an operation in which the robot of the present embodiment takes out the work 50 stored in the load lock chamber or the cassette or the like and holds it on the hand 13B will be described. At this time, it is assumed that the hand 13A is already in the retracted state and holds another work. It is assumed that the hand 13B is in the retracted state without holding the work 50. The robot moves along the rail 21 to the front of the target load lock chamber, and the height of the hand 13B is adjusted to the height of the load lock chamber by the elevating mechanism 24. Then, the arms 11B and 12B are driven, and the hand 13B moves forward and enters the inside of the load lock chamber to a position below the work 50 housed in the load lock chamber. When the hand 13B is raised by the elevating mechanism 24 in this state, the work 50 is placed on the hand 13B. At this time, a pair of sensors 27 provided on the hand 13B detects the lateral side of the work 50, and controls the amount of advance of the hand 13B so that the position of the lateral side matches the reference position on the hand 13B. To do. The tilt angle can be obtained from the detection results of the pair of sensors 27. Ideally, the tilt angle should be zero, so by rotating the hand 13B around the wrist shaft 34B so that the tilt angle detected by the pair of sensors 27 is zero, the work 50 It will be placed on the hand 13B so that the lateral side thereof and the left-right direction of the hand 13B coincide with each other. If the inclination angle is corrected when the work 50 is placed on the hand 13B, the direction of the vertical side of the work 50 and the front-back direction of the hand 13B match, so that the work in the left-right direction is the same as described later. The calculation when compensating for the 50 positions becomes simple.

When it is necessary to rotate the turntable 23 around the rotation shaft 31 and also rotate the direction of the hand 13B in the front-rear direction when the work 50 is conveyed to another load lock chamber by the robot, the value of the inclination angle. When rotating the turntable 23 around the rotation shaft 31, the amount of the inclination angle is also taken into consideration without performing an operation such that the inclination angle of the work 50 on the hand 13A is set to zero. The amount of rotation may be determined. In this case, since the inclination angle is not corrected when the work 50 is placed on the hand 13B, the time can be shortened by that amount.

When the work 50 is placed on the hand 13B in the load lock chamber, the arms 11B and 12B are driven and the hand 13B retracts to a retracted state. At this time, the workpieces 50 placed on the hands 13A and 13B are inserted into the detection space of the edge detection sensor 28, respectively. Since it is necessary to determine the horizontal position of the work 50 on the hand 13B, which is the newly placed work, the hand 13A is rotated around the wrist shaft 34A as described above, and the work on the hand 13A is rotated. The 50 is moved out of the detection space, and the position of the vertical side of the work on the hand 13B is detected by the edge detection sensor 28. From the position of the detected vertical side, the amount of displacement of the work 50 in the left-right direction in the hand 13B is determined. Based on this amount of deviation, the robot determines the amount of movement of the work 50 to be transported along the rail 21 to another load lock chamber by translation, so that the work 50 can be accurately transferred to the destination load lock chamber. You will be able to store it. When the robot moves in parallel to the transfer destination of the work 50 without correcting the inclination angle, it is necessary to consider the influence of the inclination angle when calculating the movement amount of the robot.

In the robot of the present embodiment described above, the hand is moved in the forward direction by rotating the hand around the wrist axis of the hand with the hand attached to the tip of the horizontal articulated mechanism in the retracted state. It is not necessary to move the work that is not the detection target out of the detection space of the edge detection sensor 28, and the time required to detect the position of the vertical side of the work can be shortened. Further, since the hand is not advanced, the position of the vertical side of the work can be detected even when the space around the robot is narrow.

In the robot described above, in addition to the horizontal articulated mechanism for moving the hand forward and backward, a mechanism for rotating the entire horizontal articulated mechanism around the rotation axis 31 is provided. When a load lock chamber or the like is provided on only one side of the rail 21 along the extension direction, the above-mentioned inclination angle can be compensated by the rotation of the hands 13A and 13B around the wrist shafts 34A and 34B. Therefore, it is not necessary to rotate the horizontal articulated mechanism greatly, and therefore, it is possible to attach the elevating mechanism 24 to the base 22 as it is without providing the rotating shaft 31 and the rotating table 23. Further, the above description relates to a robot having two hands 13A and 13B. Even if the number of hands is 3 or more, a hand holding a work that is not a detection target is placed around the wrist axis. By rotating the work, the time required to detect the position of the vertical side of the work can be shortened. Further, since the hand is not advanced, the position of the vertical side of the work can be detected even when the space around the robot is narrow.

11A, 11B ... 1st arm; 12A, 12B ... 2nd arm; 13A, 13B ... Hand; 21 ... Rail; 22 ... Base; 23 ... Rotating table; 24 ... Elevating mechanism; 24A ... Fixed part; 24B ... Moving part 25 ... Cover; 26 ... Support; 27 ... Sensor; 28 ... Edge detection sensor; 31 ... Rotation axis; 32 ... Common axis; 33A, 33B ... Axis; 34A, 34B ... Wrist axis; 50 ... Work.

Claims (5)

A work position detection method in a robot that has a plurality of hands and can place a work on each of the hands.
The robot includes a main body of the robot, an articulated mechanism provided for each hand and capable of advancing and retracting the hand along the first direction while fixing the direction of the hand in the first direction. An edge detection sensor that is commonly attached to the main body of the plurality of hands is provided, and the plurality of hands can be positioned so as to overlap in the vertical direction by driving the articulated mechanism. Orientation
The edge detection sensor has a detection space so as to include a region through which the work mounted on each hand passes when the plurality of hands move in the first direction, and the first one in the detection space. It is configured to detect the position of the side of the work in the second direction orthogonal to the direction.
The robot further includes, for each hand, a mechanism for rotating the hand in a direction deviating from the first direction around a wrist axis connecting the articulated mechanism and the hand.
The work that is not the target of detection is obtained by rotating the hand holding the work that is not the target of detection of the position of the side in the second direction around the wrist axis of the hand by the mechanism. A work position detection method comprising a step of exiting from the detection space and detecting the position of the side of the work to be detected of the position of the side by the edge detection sensor. The work position detection method according to claim 1, wherein the edge detection sensor is attached to the main body so as to detect the position of the side of the work placed on the hand in a retracted position. Each of the plurality of hands comprises a pair of sensors provided apart along the second direction.
When the hand is advanced toward the work in order to place the work on the hand, the inclination angle of the work with respect to the hand is obtained by using the pair of sensors, and the inclination angle is determined according to the inclination angle. The work position detection method according to claim 1 or 2, wherein the work is placed on the hand so that the inclination angle becomes 0 by rotating the hand around the wrist axis. Each of the plurality of hands comprises a pair of sensors provided apart along the second direction.
When the hand is advanced toward the work in order to place the work on the hand, the inclination angle of the work with respect to the hand is obtained by using the pair of sensors, and the inclination angle is stored. The work position detection method according to claim 1 or 2, wherein the work is placed on the hand. The articulated mechanism for each hand is attached to the main body on a common shaft.
1. The edge detection sensor is attached to the main body at a position in the forward direction from the position of the common axis when viewed from the wrist axis of the hand when retreating along the first direction. The work position detection method according to any one of 4 to 4.

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