TWI718081B - Workpiece position detection method in robot - Google Patents

Abstract

In a robot with multiple hands, the present invention eliminates the overlap of the workpieces without large hand movement, and can detect the edge position of the workpieces by edge detection sensors such as light shielding sensors. By installing them in the horizontal multi-joint mechanism, the hands (13A, 13B) can be moved forward and backward in the first direction with their orientation fixed in the first direction. Each hand (13A, 13B) is provided with a mechanism that can rotate the hand in a direction deviated from the first direction around the wrist shaft (34A, 34B) connecting the multi-joint mechanism with the hand. By rotating the hand (13A) holding the workpiece (50A) that is not the detection target around its wrist axis (34A), the workpiece (50A) is withdrawn from the detection space of the edge detection sensor (28), and the The position of the side of the workpiece (50B) to be detected is detected.

Description

Workpiece position detection method in robot

The present invention relates to a robot used for conveying plate-shaped workpieces such as glass substrates for liquid crystal display panels, and more particularly to a method for detecting the position of the workpiece on the hand of the robot.

In the production line of liquid crystal display devices, etc., robots are used to transport workpieces such as substrates between different processing devices. In this case, the workpiece is transported by inserting the hand of the robot into the load-lock chamber or cassette of the processing device that is the load-in source to hold the workpiece in the robot’s With the hand, withdraw the hand on which the workpiece is placed from the load lock vacuum chamber, etc., move the arm of the robot or the robot as a whole while the workpiece is placed on the hand, and then insert the hand until it becomes the loading destination The workpiece is stored in the load lock vacuum chamber of the processing device, and thereafter, only the hand is withdrawn from the load lock vacuum chamber. The hand has a fork-like shape, for example. The robot includes, for example, a horizontal articulated mechanism, which is constructed by connecting two arms and includes a hand at the front end; a lifting mechanism that lifts and lowers the hand together with the horizontal articulated mechanism in the vertical direction; and a rotating mechanism that uses a vertical axis as a rotation axis Make the whole horizontal multi-joint mechanism revolve in the horizontal plane. The horizontal multi-joint mechanism operates in a way that the angle formed by the two arms becomes smaller or larger, so that the hand advances or retreats on the same straight line. In order to change the direction of the hand in the horizontal plane, the hand must be rotated together with the horizontal multi-joint mechanism by a rotating mechanism. Furthermore, a conveying mechanism for linearly moving the entire robot in a horizontal plane is provided. Patent Document 1 describes an example of such a robot. In the following description, the forward and backward directions of the hand are referred to as the front-rear direction, and the direction orthogonal to the front-rear direction is referred to as the left-right direction.

If the workpiece is not placed at the designated position on the hand, there is a concern that errors may occur when the workpiece is stored in the load lock vacuum chamber as the transfer destination. In the case of a rectangular workpiece, the state in which the four sides of the workpiece are aligned in the front-rear direction and the left-right direction of the hand in a predetermined position on the hand is generally regarded as a designated position. In the following description, the side of the workpiece that should become parallel to the front and rear direction of the hand is called the longitudinal side of the workpiece, and the side that should become parallel to the left and right direction of the hand is called the lateral side of the workpiece. The deviation of the workpiece from the designated position on the hand can be thought of as follows: the deviation from the designated position in the front and rear direction of the hand, the deviation from the designated position in the left and right direction of the hand, and the lateral edge of the workpiece and the left and right direction of the hand. The deviation in the angle. The angle formed by the lateral side of the workpiece and the left and right direction of the hand is called the tilt angle. When the workpiece is at the designated position, the tilt angle is 0. Wherein, the deviation and the inclination angle in the front-rear direction can be compensated by placing a sensor for detecting the lateral side of the workpiece on the hand. When the workpiece is at the reference position, if two sensors for detecting the workpiece are arranged at two positions on the hand corresponding to the edge of the workpiece in the left-right direction, that is, the lateral side, the sensors are used for simultaneous detection By controlling the amount of advancement or retreat of the hand and the amount of rotation that rotate the hand together with the horizontal articulated mechanism by means of the lateral side, the workpiece can be placed on the hand without causing deviation in the front-rear direction and the inclination angle. Alternatively, the deviation amount can be obtained first, and the deviation amount can be compensated when the workpiece is transferred to the load lock vacuum chamber of the transfer destination.

However, regarding the deviation in the left-right direction, in the general case where the length of the lateral side of the workpiece is greater than the length of the left-right direction of the hand, the longitudinal side of the workpiece cannot be detected by the sensor installed on the hand, so it cannot be obtained. In addition, the deviation cannot be compensated. Therefore, Patent Document 2 discloses that the edge detection sensor is installed at a position that will not be affected by the operation of the horizontal multi-joint mechanism. For example, the edge detection sensor is installed in a manner fixed to the lifting mechanism. The position of the longitudinal edge of the workpiece is detected by the edge detection sensor. As the edge detection sensor, a line sensor or the like which is a light-shielding type one-dimensional position sensor can be used. The deviation in the left-right direction of the mounting position of the workpiece on the hand can be compensated by adjusting the amount of movement of the robot moving by the conveying mechanism based on the detection result of the edge detection sensor. Furthermore, in order to improve the transfer efficiency of the workpiece, Patent Document 2 discloses a robot in which two sets of horizontal articulated mechanisms that are independently controlled are provided, and a hand is attached to each horizontal articulated mechanism. The robot is configured in such a way that the advancing direction and the retreating direction of the two hands are the same with each other, and the two hands can obtain positions that accurately overlap each other in the vertical direction. The space between the hands in the up and down direction is narrow, and the left and right edges of the workpiece held on the hands are detected by a single line sensor provided as a sensor common to both hands. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2003-117862 [Patent Document 2] Japanese Patent Laid-Open No. 2008-302451

[The problem to be solved by the invention] In a robot that has two or more horizontal articulated mechanisms each including hands and is used for conveying workpieces, when the edge detection sensor for detecting the edge of the workpiece, that is, the position of the longitudinal edge, is shared between the hands, if the workpiece is If the detection space of the edge detection sensor overlaps, the edge of the workpiece cannot be detected. In order to detect the left-right position of the workpiece on the hand, no workpiece other than the workpiece to be detected can exist in the detection space of the edge detection sensor. Therefore, when two or more hands hold the workpiece, it is necessary to move the workpiece other than the workpiece to be detected so that there is no workpiece other than the workpiece to be detected in the detection space of the edge detection sensor. However, it takes time to move the hand in order to move the workpiece. In addition, depending on the position of the robot, it may be impossible to advance the hand to move the workpiece due to interference from the wall surface around the robot. When the hand cannot be moved forward due to the position of the robot, it is conceivable to move the robot to a wider space, or to change the direction of the hand together with the horizontal articulated mechanism, but it takes time to perform such an action.

The object of the present invention is to provide a method for detecting the position of a workpiece, which can detect the edge position of the workpiece without eliminating the overlap of the workpiece with large hand movement in a robot with multiple hands. [Technical means to solve the problem]

The workpiece position detection method of the present invention is a workpiece position detection method in a robot that has multiple hands and can place workpieces in each hand. The robot includes: the body of the robot; a multi-joint mechanism, which is arranged in each hand and can be When the orientation is fixed in the first direction, the hand is moved forward and backward along the first direction; and the edge detection sensor is mounted on the main body universally for multiple hands; and the multi-joint mechanism can be driven by The multiple hands are located at positions overlapping in the vertical direction. The edge detection sensor has a detection space to include the area through which the workpiece mounted on each hand passes when the multiple hands move in the first direction. The robot is configured to detect the position of the side of the workpiece in the second direction orthogonal to the first direction in the detection space, and the robot further in each hand includes the wrist axis connecting the multi-joint mechanism with the hand from the first A mechanism that rotates in a direction deviated from one direction, and the workpiece position detection method has the following steps: The mechanism is used to rotate the hand holding the workpiece that is not the detection target of the position of the side in the second direction around the wrist axis of the hand Thus, the workpiece that is not the detection target is withdrawn from the detection space, and the edge detection sensor is used to detect the position of the side of the workpiece that is the detection target of the side position.

According to the workpiece position detection method of the present invention, only by rotating the hand around the wrist axis, the overlap of the workpiece can be eliminated, and the edge detection sensor can be used to detect the edge of the workpiece to be detected. Therefore, it is possible to reduce the need for moving the hand. The time needed to wait.

In the workpiece position detection method of the present invention, it is preferable that the edge detection sensor is mounted on the main body so as to detect the position of the side of the workpiece placed on the hand at the retracted position. The hand in the retracted position is in a state where it is least likely to be interfered from the wall surface around the robot. Therefore, this configuration can reduce the space that must be installed around the robot in order to eliminate the overlap of the workpieces, so it is possible to save space to install the robot .

In the workpiece position detection method of the present invention, each of the plurality of hands includes a pair of sensors spaced apart along the second direction, and when the hands are moved toward the workpiece in order to place the workpiece on the hand, a pair of sensors are used. The sensor obtains the tilt angle of the workpiece with respect to the hand, and rotates the hand around the wrist axis corresponding to the tilt angle, so that the workpiece can be placed on the hand so that the tilt angle becomes zero. By placing the workpiece on the hand as described above, the calculation of the movement amount of the robot when the placed workpiece is transferred to the transfer destination can be simplified.

Alternatively, in the method for detecting the position of the workpiece of the present invention, the plurality of hands may each include a pair of sensors spaced apart along the second direction, and when the workpiece is placed on the hand, the hand faces the workpiece. When advancing, a pair of sensors is used to obtain the tilt angle of the workpiece relative to the hand, and the tilt angle is stored to place the workpiece on the hand. In this case, the hand angle correction based on the tilt angle is not performed, so the time can be shortened accordingly.

In the workpiece position detection method of the present invention, it is preferable that after the multi-joint mechanism of each hand is mounted on the main body on the common axis, when viewed from the wrist axis of the hand when retreating in the first direction, the position is compared with the position of the common axis. Install the edge detection sensor on the main body at the position in the forward direction. According to this structure, when the hand is in the backward position, the edge detection sensor can detect the edge of the workpiece, and the distance between the wrist axis and the edge detection sensor can be fully obtained, so that the holding of the workpiece that is not the detection target can be reduced. The angle of rotation when the hand rotates around the wrist axis. [Effects of the invention]

According to the present invention, in a robot having a plurality of hands, the overlap of the workpieces is eliminated without large hand movement, and the edge positions of the workpieces can be detected.

Next, a preferred embodiment of the present invention will be described with reference to the drawings. Fig. 1 (a) and (b) show a robot according to an embodiment of the present invention, and (a) and (b) are a side view and a plan view, respectively. The robot shown in (a) and (b) of FIG. 1 is a horizontal articulated type robot that conveys a roughly rectangular plate-shaped workpiece 50 such as a glass substrate used in the manufacture of liquid crystal display panels, and is a horizontal articulated robot including holding A so-called two-handed robot with two hands 13A and 13B of the workpiece 50. In addition, FIG. 2 shows a state where the horizontal articulated mechanism has been raised in the robot shown in (a) and (b) of FIG. 1.

The robot includes: a base 22, which can move on a pair of parallel guide rails 21 arranged in a straight line on the ground; a rotating table 23, which is arranged on the base 22, with a motor (not shown) built into the base 22 , Rotating around the rotating shaft 31 in a horizontal plane; and the lifting mechanism 24 is arranged in an upright manner relative to the rotating table 23. A cover 25 covering the rail 21 is attached. The elevating mechanism 24 includes a fixed portion 24A attached to the rotating table 23, and a moving portion 24B that is raised and lowered relative to the fixed portion 24A by a motor not shown. Fig. 1(a) shows the robot of the present embodiment in a state where the moving part 24B of the elevating mechanism 24 is located at the bottom of the lifting range. In contrast, Fig. 2 shows the robot in a state where the moving part 24B is raised. The supporting part 26 holding the horizontal articulated mechanism is provided in the moving part 24B so as to extend in the horizontal direction, and two sets of horizontal articulated mechanisms are arranged in the vertical direction and installed at the front end of the supporting part 26. The horizontal multi-joint mechanism on the upper side includes a first arm 11A that is mounted on the support portion 26 and can rotate in a horizontal plane around the universal axis 32, and a second arm that is mounted on the front end of the first arm 11A and can rotate in a horizontal plane around the axis 33A. 12A, a hand 13A is attached to the front end of the second arm 12A. Similarly, the horizontal multi-joint mechanism on the lower side includes a first arm 11B that is mounted on the support 26 and can rotate in a horizontal plane around the universal axis 32, and is mounted on the front end of the first arm 11B and can rotate around the axis 33B in the horizontal plane. The second arm 12B has a hand 13B attached to the front end of the second arm 12B. In the robot, the parts other than the horizontal articulated mechanism and the hands 13A and 13B attached to it are the body of the robot.

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 workpiece 50 can be held in a horizontal state by being held from below and conveyed. In the state of holding the workpiece 50, the entire hand 13A and the hand 13B are covered by the workpiece 50 except for the base side which is the connection position with the second arm 12A and the second arm 12B. When the hand 13A and the hand 13B take out the workpiece 50 stored in the load lock vacuum chamber and hold it on the hand 13A and the hand 13B, or store the held workpiece 50 in the load lock vacuum chamber, etc., move forward relative to the workpiece 50 Or retreat, and set the forward or backward direction of the hand 13A and the hand 13B to be a direction parallel to the extending direction of the rod-shaped member. The width in the left-right direction of the hand 13A and the hand 13B in the direction orthogonal to the front-rear direction is shorter than the width in the left-right direction of the workpiece 50 to be conveyed.

In the robot, the horizontal articulated mechanism is configured as follows: by assembling a link mechanism of the first arm 11A, the first arm 11B, the second arm 12A, and the second arm 12B, the hand 13A and the hand 13B are The forward movement and the backward movement are performed in a linear motion in a direction orthogonal to the direction in which the support portion 26 extends. That is, the two hands 13A and 13B move forward and backward in the same direction. The movement of the front ends of the hands 13A and 13B away from the common shaft 32 is forward movement, and the movement in the opposite direction to the forward movement is backward movement. The first arm 11A, the first arm 11B, the second arm 12A, and the second arm 12B perform a bending movement as a whole. In order to keep the orientation of the hands 13A and 13B in the horizontal plane fixed, the hands 13A and 13B are respectively It is installed at the positions of the front ends of the second arm 12A and the second arm 12B so as to be rotatable around the wrist axis 34A and the wrist axis 34B in a horizontal plane. By driving a motor (not shown) provided in the support part 26, the first arm 11A and the second arm 12A of the horizontal articulated mechanism on the upper side move, and the hand 13A faces the support part 26 while maintaining its orientation. Move in the direction orthogonal to the extension direction. Similarly, by driving a motor (not shown) provided in the support portion 26, the first arm 11B and the second arm 12B of the horizontal articulated mechanism on the lower side move, and the hand 13B faces and The extension direction of the support portion 26 moves in a direction orthogonal to the extension direction. In the robot, the hand 13A and the hand 13B can be moved independently. During the movement of the hand 13A and the hand 13B, the wrist axis 34A and the wrist axis 34B can be accurately arranged in the vertical direction, that is, the hand 13A and the hand 13B can be Accurately overlap each other in the up and down direction.

Both the hand 13A and the hand 13B include a sensor 27 for detecting the lateral side of the rectangular workpiece 50 and located on the lateral side of the hand 13A and the hand 13B in the backward direction. Sensors 27 are provided at two ends of each of the hands 13A and 13B in the left-right direction. By using the sensors 27, the position of the workpiece 50 in the front-rear direction of the hands 13A and 13B can be performed. Compensation for the deviation, and compensation for the inclination angle formed by the lateral side of the workpiece 50 and the left and right directions of the hand 13A and the hand 13B.

Furthermore, an edge detection sensor 28 including, for example, a light-shielding sensor is installed in the robot at a position that is stationary with respect to the support part 26 on which the horizontal articulated mechanism is mounted, and if it is a workpiece 50 Keeping the state of the hand 13A and the hand 13B, the longitudinal edge of the workpiece 50 passes through the forward and backward movement of the hand 13A and the hand 13B. In the example shown here, the edge detection sensor 28 is mounted on the moving part 24B of the lifting mechanism 24. The edge detection sensor 28 is a sensor that detects the deviation in the left-right direction of the placement position of the workpiece 50 on the hand 13A and the hand 13B, and includes, for example, one-dimensional detection of the position in the left-right direction of the longitudinal edge of the workpiece 50 Sensor. The edge detection sensor 28 has a U-shaped outer shape, and uses the opening formed by the U as a detection space, and detects the longitudinal edge of the workpiece 50 when the workpiece 50 enters the detection space. The edge detection sensor 28 is commonly provided for the workpiece 50 held by the two hands 13A, 13B. In the robot of this embodiment, the space between the hands 13A and 13B in the vertical direction is fixed, and the opening width of the opening of the edge detection sensor 28 is larger than the space between the hands 13A and 13B. When both the hands 13A and 13B carry the workpiece 50, the workpiece 50 can pass through. The robot of this embodiment is a transfer robot. The workpiece 50 is taken out from the load lock vacuum chamber by moving the hands 13A and 13B forward. In addition, the workpiece 50 is stored in the load lock vacuum chamber. In the state where the hand 13A and the hand 13B are advancing, the workpiece 50 is separated from the detection space, and in the state where the hand 13A and the hand 13B have been moved back, the workpiece 50 enters the detection space.

Even if the edge detection sensor 28 is commonly provided for the workpiece 50 mounted on the hand 13A and the hand 13B, in order to detect the position of the side of the workpiece 50, it is necessary that only the detection target exists in the detection space of the edge detection sensor 28. The workpiece 50 cannot exist in the detection space, which is not a detection target. In the state where both the hands 13A and 13B hold the workpiece 50, it is necessary to move the hand that does not hold the workpiece 50 of the inspection target, so that only the workpiece 50 of the inspection target exists in the inspection space. Conventionally, the hand carrying the workpiece 50 that is not the object of inspection is moved forward, so that only the workpiece 50 of the inspection object exists in the inspection space. However, it takes time to move the hand as described above. It is difficult to move the hand as described above due to the collision of the wall surface. Therefore, in the present embodiment, as the robot, a robot is used which is configured to surround the wrist axis 34A and the wrist axis 34B by the unillustrated motors provided on the hands 13A and 13B, respectively. Rotate within a range of, for example, ± several degrees from the original front-rear direction. In addition, the hand holding the workpiece 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 workpiece 50 held by the hand rotating around the wrist axis is separated from the detection space of the edge detection sensor 28, so that only the workpiece 50 of the detection target can exist in the detection space.

(A) to (f) of FIG. 3 are diagrams schematically showing the detection of the longitudinal edge of the workpiece 50 using the edge detection sensor 28 in the robot of the present embodiment. As the work 50, a glass substrate is assumed, and when shown in a plan view, the other side of the work 50 is transparent and visible. For the purpose of explanation, the workpiece 50 held by the hand 13A and the hand 13B are respectively expressed as a workpiece 50A and a workpiece 50B. (A) is a plan view showing a state where the hands 13A and 13B are located at the retreat position and overlap in the vertical direction, and (b) is a side view corresponding to (a). There are two pieces of work 50A, 50B in the detection space of the edge detection sensor 28, and therefore, neither the work 50A nor the work 50B can detect the edge position. Here, if the position of the side of the workpiece 50B held by the lower hand 13B is detected, in this embodiment, the upper hand 13A is rotated around its wrist axis 34A so as to be away from the edge detection sensor 28 . As a result, the workpiece 50A held by the upper hand 13A is separated from the detection space of the edge detection sensor 28, and the edge detection sensor 28 can detect the side of the workpiece 50B held by the lower hand 13B. In (a) to (f) of FIG. 3, (c) is a plan view showing a state where the hand 13A has been rotated around the wrist axis 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 inclined from the original front-rear direction, it is necessary to advance the hand holding the workpiece 50 that is not the detection target. In the example shown in (a) to (f) of FIG. 3, in order to detect the side of the workpiece 50B held by the lower hand 13B, the upper hand 13A must be advanced. In (a) to (f) of FIG. 3, (e) is a plan view showing a state where the upper hand 13A has been 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 equipped with the hands 13A and 13B is raised and lowered in the vertical direction, it is preferable that the edge of the workpiece 50 can be detected regardless of the height of the hands 13A and 13B. Therefore, it is preferable to use the horizontal articulated mechanism in a robot. An edge detection sensor 28 is provided at the position where the mechanism is raised and lowered together. In the transport robot, in order to prevent the workpiece 50 or the hands 13A and 13B from colliding with surrounding objects when the entire robot moves in parallel on a horizontal plane, the hands 13A and 13B are moved backwards during the parallel movement. It is preferable that the detection of the longitudinal edge of the workpiece 50 is also performed when the hands 13A and 13B are in the retracted state. In addition, when the hand holding a workpiece other than the detection target is rotated around its wrist axis, the amount of rotation is preferably small. From the viewpoint of reducing the amount of rotation, it is preferable to install the edge detection sensor 28 as far as possible from the position of the wrist axis when the hand is in the backward state. For example, when viewed from the wrist axis 34A and wrist axis 34B of the hand 13A and the hand 13B in the backward state, it is preferable to be at a position on the forward direction side compared to the mounting position of the horizontal articulated mechanism in the support 26, that is, the position of the universal shaft 32 , Install the edge detection sensor on the robot.

Next, the operation of the robot of the present embodiment to take out the workpiece 50 stored in the load lock vacuum chamber or the cassette and hold it on the hand 13B will be described. At this time, the hand 13A has been set as a hand that is in a retreat state and holds another workpiece. The hand 13B is a hand that does not hold the workpiece 50 and is in a retreat state. The robot moves along the guide rail 21 to the front of the target load lock vacuum chamber, and the height of the hand 13B is aligned with the height of the load lock vacuum chamber by the lifting mechanism 24. Then, the arm 11B and the arm 12B are driven to advance the hand 13B, and enter the inside of the load lock vacuum chamber until it is stored in a position below the workpiece 50 in the load lock vacuum chamber. In this state, if the hand 13B is raised by the lifting mechanism 24, the workpiece 50 is placed on the hand 13B. At this time, the lateral side of the workpiece 50 is detected by a pair of sensors 27 provided on the hand 13B, and the advancement of the hand 13B is controlled so that the position of the lateral side is consistent with the reference position in the hand 13B. The inclination angle can be obtained from the detection results of the pair of sensors 27. Ideally, the inclination angle should be zero, so the hand 13B is rotated around the wrist axis 34B in such a way that the inclination angle detected by the pair of sensors 27 becomes zero, so that the workpiece 50 is aligned with the left and right directions of the hand 13B with its lateral side It is placed on the hand 13B in a consistent manner. If the inclination angle is corrected when the workpiece 50 is placed on the hand 13B, the orientation of the longitudinal side of the workpiece 50 is consistent with the front and rear direction of the hand 13B. Therefore, the calculation of the position of the workpiece 50 in the left and right directions is performed as described later. It becomes simple.

When the workpiece 50 is transported to, for example, another load lock vacuum chamber by a robot, it is necessary to rotate the turntable 23 around the rotation axis 31 to rotate the front and rear direction of the hand 13B. After the value, no action such as making the tilt angle of the workpiece 50 on the hand 13A zero is performed, and the amount of rotation can be determined by considering the tilt angle when rotating the turntable 23 around the rotation axis 31. In this case, when the workpiece 50 is placed on the hand 13B, the inclination angle is not corrected, so the time can be shortened accordingly.

When the workpiece 50 is placed on the hand 13B in the load lock vacuum chamber, the arm 11B and the arm 12B are driven to retreat the hand 13B and become a retreat state. At this time, the workpiece 50 placed on the hand 13A and the hand 13B respectively enters the detection space of the edge detection sensor 28. Since it is necessary to determine the position in the left-right direction of the workpiece 50 on the hand 13B that is the newly placed workpiece, the hand 13A is rotated around its wrist axis 34A as described so that the workpiece 50 on the hand 13A is withdrawn from the detection space. The position of the longitudinal edge of the workpiece on the hand 13B is detected by the edge detection sensor 28. Based on the detected position of the longitudinal side, the amount of deviation of the workpiece 50 in the left-right direction in the hand 13B is determined. Based on the deviation amount, the robot moves the workpiece 50 along the guide rail 21 to the other load lock vacuum chamber by moving in parallel, so that the workpiece 50 can be accurately stored in the load lock of the transfer destination. Vacuum chamber. In addition, when the robot moves in parallel to the transfer destination of the workpiece 50 without correcting the tilt angle, the influence of the tilt angle must be considered when calculating the movement amount of the robot.

In the robot of the present embodiment described above, in the state where the hand attached to the front end of the horizontal articulated mechanism is turned back, the hand is rotated around the wrist axis of the hand, thereby eliminating the need to move the hand in the forward direction By moving the workpiece that is not a detection target to exit from the detection space of the edge detection sensor 28, the time required for detection of the position of the longitudinal edge of the workpiece can be shortened. In addition, since the hand is not moved forward, even when the space around the robot is small, the position of the longitudinal edge of the workpiece can be detected.

In the robot, 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 rotating shaft 31 is provided. When a load lock vacuum chamber or the like is provided on only one side along the extension direction of the guide rail 21, the inclination angle can be compensated by the rotation of the hand 13A and the hand 13B around the wrist axis 34A and the wrist axis 34B. It is not necessary to rotate the horizontal multi-joint mechanism by a large amount, and therefore, it is possible to directly mount the lifting mechanism 24 on the base 22 without providing the rotating shaft 31 or the rotating table 23. In addition, the above description is about a robot with two hands 13A and 13B. However, even if the number of hands is three or more, by rotating the hand holding the workpiece that is not the inspection target around its wrist axis, The time required for detection of the position of the longitudinal edge of the workpiece can be shortened. In addition, since the hand is not moved forward, even when the space around the robot is small, the position of the longitudinal edge of the workpiece can be detected.

11A, 11B: First arm 12A, 12B: second arm 13A, 13B: hands 21: Guide rail 22: Pedestal 23: Rotating table 24: Lifting mechanism 24A: Fixed part 24B: Mobile Department 25: cover 26: Support 27: Sensor 28: Edge detection sensor 31: Rotation axis 32: General axis 33A, 33B: shaft 34A, 34B: wrist axis 50, 50A, 50B: Workpiece

Fig. 1 (a) and (b) are respectively a side view and a plan view of a robot according to an embodiment of the present invention. Fig. 2 is a side view showing the robot in a state where the horizontal articulated mechanism has been raised. (A) to (f) of FIG. 3 are diagrams explaining the movement of the hand of the robot.

13A, 13B: hands 28: Edge detection sensor 50A, 50B: Workpiece

Claims (8)

A method for detecting the position of a workpiece is a method for detecting the position of a workpiece in a robot having multiple hands and capable of placing a workpiece on each of the hands, The robot includes: a body of the robot; a multi-joint mechanism, which is provided on each hand, and can make the hand advance and retreat in the first direction while the orientation of the hand is fixed in the first direction; And an edge detection sensor, which is commonly installed on the main body for the plurality of hands; and is configured to be able to locate the plurality of hands at positions overlapping in the vertical direction by driving the multi-joint mechanism, The edge detection sensor has a detection space to include an area through which the workpiece mounted on each hand passes when the plurality of hands move in the first direction, so as to detect and The position of the side of the workpiece in the second direction orthogonal to the first direction, The robot further includes a mechanism for rotating the hand in a direction deviated from the first direction around the wrist axis connecting the multi-joint mechanism and the hand in each hand, The workpiece position detection method has the following steps: by the mechanism, the hand holding the workpiece that is not the detection target of the position of the side in the second direction surrounds the wrist axis of the hand Rotate, thereby causing the workpiece that is not the detection target to withdraw from the detection space, and the edge detection sensor is used to detect the side of the workpiece that is the detection target of the position of the side s position. The workpiece position detection method according to claim 1, wherein the edge detection sensor is mounted on the side of the workpiece placed on the hand in the retracted position. Ontology. The workpiece position detection method according to claim 1, wherein each of the plurality of hands includes a pair of sensors spaced apart along the second direction, When the hand is advanced toward the workpiece in order to place the workpiece on the hand, the pair of sensors is used to obtain the inclination angle of the workpiece with respect to the hand, which corresponds to The tilt angle causes the hand to rotate around the wrist axis, thereby placing the workpiece on the hand such that the tilt angle becomes zero. The workpiece position detection method according to claim 1, wherein each of the plurality of hands includes a pair of sensors spaced apart along the second direction, When the hand is advanced toward the workpiece in order to place the workpiece on the hand, the pair of sensors is used to obtain the inclination angle of the workpiece with respect to the hand and store the The tilt angle is used to place the workpiece on the hand. The workpiece position detection method according to any one of claims 1 to 4, wherein the multi-joint mechanism of each hand is mounted on the body on a common shaft, The edge detection sensor is viewed from the wrist axis of the hand when retreating in the first direction, and is attached to the main body at a position in a forward direction compared to a position of the general axis. The workpiece position detection method according to claim 2, wherein the plurality of hands respectively include a pair of sensors spaced apart along the second direction, When the hand is advanced toward the workpiece in order to place the workpiece on the hand, the pair of sensors is used to obtain the inclination angle of the workpiece with respect to the hand, which corresponds to The tilt angle causes the hand to rotate around the wrist axis, thereby placing the workpiece on the hand such that the tilt angle becomes zero. The workpiece position detection method according to claim 2, wherein the plurality of hands respectively include a pair of sensors spaced apart along the second direction, When the hand is advanced toward the workpiece in order to place the workpiece on the hand, the pair of sensors is used to obtain the inclination angle of the workpiece with respect to the hand and store the The tilt angle is used to place the workpiece on the hand. The workpiece position detection method according to claim 6 or 7, wherein the multi-joint mechanism of each hand is mounted on the body on a common shaft, The edge detection sensor is viewed from the wrist axis of the hand when retreating in the first direction, and is attached to the main body at a position in a forward direction compared to a position of the general axis.

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