Robot teaching device and target position calculation method

Abstract

The present invention provides a robot teaching device and a target position calculation method that can accurately search for the position of a predetermined marker based on the distribution of light received while a transport robot is moving, and appropriately calculate the target position for transporting a flat object based on the position of the predetermined marker. [Solution] The robot teaching device 100 includes a first sensor 21 and a second sensor 22 arranged on the transport robot 10, a light-receiving amount distribution generation unit 120 that generates a first light-receiving amount distribution L10 and a second light-receiving amount distribution L20 in the trajectory of the optical axis intersection point PX while the transport robot 10 is moved by the robot control unit 110, a search unit 130 that searches for a light-shielding point based on the first light-receiving amount distribution L10 and the second light-receiving amount distribution L20, a marker position calculation unit 140 that calculates the position of a predetermined marker based on the position of the transport robot 10 at the light-shielding point, and a target position calculation unit 150 that calculates a target position based on the predetermined marker position.

Description

Technical Field

[0001] The present invention relates to a robot teaching device and a target position calculation method.

Background Art

[0002] In recent years, many robots have become widespread in the industrial world. Such robots are used, for example, in the assembly, welding, and conveyance of electronic components and mechanical parts, and the efficiency and automation of factory production lines are being pursued.

[0003] In a transfer robot that transfers wafers used in semiconductor manufacturing equipment, teaching for transferring the wafers to an appropriate position is performed, but the accuracy depends on the knowledge and proficiency of the operator, and there are cases where space saving is required to such an extent that the work space of the operator cannot be secured sufficiently, so automation of teaching is being pursued.

[0004] For example, in Patent Document 1, a transmissive optical sensor including two sets of light projecting units and light receiving units is attached to a finger unit, and the finger unit is operated to a position where two optical axes simultaneously detect a target kinematic pin, thereby teaching a predetermined target position based on the detection of the kinematic pin. The position where two optical axes simultaneously detect a kinematic pin is a position where both optical axes become tangents to the outer peripheral circle of the kinematic pin.

[0005] In the position teaching method disclosed in Patent Document 1, if the position where two optical axes simultaneously detect is unclear, the arm unit is retracted, and then the turning unit is operated left and right to memorize the positions where the respective optical axes detect the kinematic pin. After operating the turning unit to an intermediate position, the arm unit is operated to try to detect the position where two optical axes simultaneously detect.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-183492 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the position teaching method disclosed in Patent Document 1 simply searches for a position where both optical axes simultaneously detect the kinematic pin (marker) at an intermediate position between the positions where each optical axis detects the marker. Therefore, there is a risk that this position may not be properly searched.

[0008] Therefore, the present invention aims to provide a robot teaching device and a target position calculation method that can accurately search for the position of a predetermined marker based on the distribution of light received while moving a transport robot, and appropriately calculate the target position for transporting a flat object based on the position of the predetermined marker. [Means for solving the problem]

[0009] A robot teaching device according to one aspect of the present invention is a robot teaching device for a transport robot that transports a flat object, comprising: a robot control unit that controls the movement of the transport robot; a first light-emitting unit arranged on the transport robot that emits first light having a first optical axis, and a second light-emitting unit that emits second light having a second optical axis intersecting the first optical axis; a first light-receiving unit capable of receiving first light and a second light-receiving unit capable of receiving second light; and, while the transport robot is moved by the robot control unit, a first light-receiving amount distribution based on the first light-receiving amount received by the first light-receiving unit and a second light-receiving amount received by the second light-receiving unit in the trajectory of the optical axis intersection point where the first optical axis and the second optical axis intersect. The system includes: a light-receiving amount distribution generation unit that generates a second light-receiving amount distribution based on the amount; a search unit that searches for a light-shielding point where at least a portion of the first light received by the first light-receiving unit and at least a portion of the second light received by the second light-receiving unit are shielded by a predetermined marker, based on the first and second light-receiving amount distributions generated by the light-receiving amount distribution generation unit; a marker position calculation unit that calculates the position of a predetermined marker based on the position of the transport robot at the light-shielding point searched by the search unit; and a target position calculation unit that calculates a target position for transporting a flat object based on the position of a predetermined marker calculated by the marker position calculation unit.

[0010] In this embodiment, a transport robot is equipped with a first light-emitting unit and a first light-receiving unit, and a second light-emitting unit and a second light-receiving unit. The light-receiving amount distribution generation unit generates a first light-receiving amount distribution and a second light-receiving amount distribution along the trajectory of the optical axis intersection while the transport robot is moved by the robot control unit. The search unit searches for shading points based on the first light-receiving amount distribution and the second light-receiving amount distribution. The marker position calculation unit calculates the position of a predetermined marker based on the position of the transport robot at the shading point, and the target position calculation unit calculates the target position for transporting the flat object based on the predetermined marker position. As a result, the position of the predetermined marker can be searched with high accuracy, and the target position for transporting the flat object can be appropriately calculated based on the predetermined marker position.

[0011] In the above embodiment, the search unit may search for a shading point based on a first range in the first light reception distribution in which at least a portion of the first light received by the first light receiving unit is shaded by a predetermined marker, and a second range in the second light reception distribution in which at least a portion of the second light received by the second light receiving unit is shaded by a predetermined marker.

[0012] According to this embodiment, the search unit searches for shading points based on a first range of the first light reception distribution and a second range of the second light reception distribution, thereby enabling the appropriate search for shading points.

[0013] In the above embodiment, the search unit may search for a light-shielding point based on the overlapping range of the first range and the second range.

[0014] According to this embodiment, the search unit searches for shading points based on the overlapping range of the first range and the second range, thereby enabling a more appropriate search for shading points.

[0015] In the above embodiment, the system may further include an interpolation unit that interpolates the first and second light-receiving amounts between the trajectories of the optical axis intersections, and generates a first light-receiving amount distribution based on the first light-receiving amount and a second light-receiving amount distribution based on the second light-receiving amount between the trajectories of the optical axis intersections.

[0016] According to this embodiment, the interpolation unit interpolates the first and second light-receiving amounts between the trajectories of the optical axis intersection, thereby improving the resolution of the generated first light-receiving amount distribution and the second light-receiving amount distribution.

[0017] In the above embodiment, the statement that at least a portion of the first light received by the first light receiving unit is blocked by a predetermined mark, or that at least a portion of the second light received by the second light receiving unit is blocked by a predetermined mark, may include a state in which the amount of first light received by the first light receiving unit, or the amount of second light received by the second light receiving unit, is below a threshold.

[0018] According to this embodiment, even if the first and second rays are not completely blocked due to light diffraction or the like, it is possible to appropriately determine that the light is blocked.

[0019] In the above embodiment, the predetermined marker may be a pin on which a flat object is placed.

[0020] According to this embodiment, by using a pin whose relative position to the target position is known as a predetermined marker, the target position can be appropriately calculated without having to place a predetermined marker separately.

[0021] A target position calculation method according to one aspect of the present invention is a target position calculation method performed by a robot teaching device of a transport robot that transports a flat object, wherein the transport robot is equipped with a first light emitting unit that emits first light having a first optical axis, a second light emitting unit that emits second light having a second optical axis intersecting the first optical axis, a first light receiving unit capable of receiving the first light, and a second light receiving unit capable of receiving the second light, and the method comprises a robot control step that controls the movement of the transport robot, and while moving the transport robot in the robot control step, a first light receiving amount based on the first light receiving amount received by the first light receiving unit in the trajectory of the optical axis intersection point where the first optical axis and the second optical axis intersect The method includes: a light-receiving amount distribution generation step that generates a cloth and a second light-receiving amount distribution based on the second light-receiving amount received by the second light-receiving unit; a search step that searches for a light-shielding point where at least a portion of the first light received by the first light-receiving unit and at least a portion of the second light received by the second light-receiving unit are shielded by a predetermined marker, based on the first light-receiving amount distribution and the second light-receiving amount distribution generated in the light-receiving amount distribution generation step; a marker position calculation step that calculates the position of a predetermined marker based on the position of the transport robot at the light-shielding point searched in the search step; and a target position calculation step that calculates a target position based on the position of a predetermined marker calculated in the marker position calculation step.

[0022] According to this aspect, a first light projecting unit and a first light receiving unit, and a second light projecting unit and a second light receiving unit are arranged on the transfer robot. In the light reception amount distribution generation step, while moving the transfer robot in the robot control step, the first light reception amount distribution and the second light reception amount distribution on the locus of the optical axis intersection are generated. In the search step, a light shielding point is searched based on the first light reception amount distribution and the second light reception amount distribution. In the mark position calculation step, the position of a predetermined mark is calculated based on the position of the transfer robot at the light shielding point. In the target position calculation step, the target position for transferring the flat object is calculated based on the position of the predetermined mark. As a result, the position of the predetermined mark can be searched with high accuracy, and the target position for transferring the flat object can be appropriately calculated based on the position of the predetermined mark.

Effect of the Invention

[0023] According to the present invention, it is possible to provide a robot teaching device and a target position calculation method capable of accurately searching for the position of a predetermined mark based on the light reception amount distribution received while moving the transfer robot, and appropriately calculating the target position for transferring the flat object based on the position of the predetermined mark.

Brief Description of the Drawings

[0024] [Figure 1] It is a schematic diagram showing the system configuration of the transfer robot system 1 according to an embodiment of the present invention. [Figure 2] It is a schematic diagram showing the state where the transfer robot 10 operates in a clean environment. [Figure 3] It is a diagram schematically showing the state where two sets of optical sensors are arranged on the hand 11 of the transfer robot 10. [Figure 4] It is a functional block diagram showing each function of the robot teaching device 100 according to an embodiment of the present invention. [Figure 5] It is a diagram showing the state where the transfer robot 10 (hand 11) is rotated (θ axis) or moved forward (X axis) by the robot control unit 110 and heads toward the pin P1 arranged on the stage S. [Figure 6]This figure shows the trajectories T1-T5 of the optical axis intersection point PX near pin P1 when generating the first and second light reception distributions. [Figure 7] This figure shows the first light reception distribution L10 based on the first light reception amount and the second light reception distribution L20 based on the second light reception amount, along the trajectory T1 to T5 of the optical axis intersection point PX shown in Figure 6. [Figure 8] This figure shows how to identify the position in the first light reception distribution L10 and the second light reception distribution L20 shown in Figure 7 that results in a predetermined light-shielding state. [Figure 9] This figure shows how the light-shielding points are searched for with even greater precision. [Figure 10] This diagram shows how the center position P10 of pin P1 is calculated. [Figure 11] This is a flowchart showing the processing flow of the target position calculation method M100, which calculates the target position for transporting an object executed by a robot teaching device 100 according to one embodiment of the present invention. [Figure 12] This is a flowchart showing the flow of the light reception distribution generation process in step S106. [Figure 13] This is a flowchart showing the search process flow in step S107. [Figure 14] This figure schematically shows how the first light reception distribution L10 and the second light reception distribution L20 shown in Figure 7 are interpolated. [Figure 15] This figure shows the other trajectory T6 of the optical axis intersection point PX near pin P1. [Figure 16] This is a schematic diagram illustrating another method for calculating the center position P10 of pin P1. [Figure 17] This diagram schematically shows how two sets of optical sensors are arranged in different ways on the hand 11 of the transport robot 10. [Modes for carrying out the invention]

[0025] The embodiments of the present invention will be described below in detail with reference to the drawings. The embodiments described below are merely examples of how to implement the present invention and are not intended to limit the scope of the invention. Furthermore, to facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations may be omitted.

[0026] <One Embodiment> [Configuration of the transport robot system] Figure 1 is a schematic diagram showing the system configuration of a transport robot system 1 according to one embodiment of the present invention. As shown in Figure 1, the transport robot system 1 comprises a transport robot 10, a sensor monitoring device 20, a robot control device 30, and an operating device 40.

[0027] The transport robot 10 is, for example, a horizontal articulated robot intended for wafer transport, and is a clean transport robot used for transport in clean environments in the manufacturing of semiconductor devices and flat panel displays, and in the medical and food industries. In this embodiment, the transport robot 10 is, for example, a two-axis or three-axis cylindrical coordinate type, and has a hand 11 as an end effector, and is described as a robot that holds and transports wafers (objects) with the hand 11.

[0028] The hand 11 is equipped with two sets of optical sensors. These two sets of optical sensors may be, for example, fiber optic sensors having a light-emitting unit that emits light and a light-receiving unit that can receive the light emitted from the light-emitting unit. Details regarding the arrangement of the two sets of optical sensors will be described later.

[0029] The sensor monitoring device 20 controls and monitors the two sets of optical sensors located on the hand 11. For example, the sensor monitoring device 20 may control the light emitted from each light-emitting part of the two sets of optical sensors, or it may monitor each light-receiving part of the two sets of optical sensors and detect the light (amount of light received) received by each light-receiving part.

[0030] The robot control device 30 is a device that controls the operation of the transport robot 10. For example, the robot control device 30 is connected to the operating device 40 and can acquire operation instruction information input to the operating device 40. Based on this operation instruction information, the robot control device 30 operates each axis of the transport robot 10, as well as the arms and hands 11, to start and stop the transport robot 10, pick up an object, transport and place it.

[0031] The operating device 40 is, for example, a teach pendant, and receives input from the operator regarding operation instruction information for the transport robot 10, specifically concerning transport operations that transport an object. Typically, the operator uses the teach pendant to input appropriate instruction information for, for example, starting and stopping the transport robot 10, as well as settings for the transport robot 10, the operation of the arm and hand 11, and the registration of teaching points.

[0032] Furthermore, regarding the registration of teaching points, the operator may sequentially register the teaching points along the movement path using a teach pendant while operating the transport robot 10, or the teaching points may be automatically registered in automatic teaching. Automatic teaching is effective, for example, in environments or situations where sufficient space (workspace) for the operator to enter cannot be secured.

[0033] In Figure 1, the operating device 40 is connected to the robot control device 30 via a cable, but it may also be connected wirelessly. That is, the operating device 40 and the robot control device 30 may be equipped with a communication unit for wireless communication. By connecting the robot control device 30 and the operating device 40 wirelessly, the operator can input operation instruction information while moving freely without being bothered by the presence of cables or having their range of movement limited by the length of the cables.

[0034] [Wafer transport process] Figure 2 is a schematic diagram showing how the transport robot 10 operates in a clean environment. As shown in Figure 2, the transport robot 10, installed in the workspace WS, holds the wafer W in its hand 11 and transports it to each stage S1 to S3 (hereinafter sometimes collectively referred to as "stage S") in the process chamber under vacuum conditions.

[0035] Specifically, the transport robot 10 operates its arms and hands 11 based on motion instruction information from the robot control device 30 to pick up wafers W and transport them to the destination stage S.

[0036] Here, the target position for transporting and placing the wafer W is, for example, the center of the stage S, and it is preferable that the wafer W be placed with high precision at the center of the stage S. The robot control device 30 actually transports the wafer W and places it at the target position, the center of the stage S, based on the teaching data. At that time, the robot control device 30 can generate high-precision teaching data by detecting predetermined markers placed on the stage S and appropriately determining the center position (target position) of the stage S based on these predetermined markers. As a result, the wafer W can be placed with high precision at the center of the stage S.

[0037] In other words, it is important to accurately determine the center position (target position) of stage S by appropriately detecting the positions of predetermined markers placed on stage S. Below, we will explain a method for accurately determining the center position (target position) of stage S by appropriately detecting the positions of predetermined markers placed on stage S using two sets of optical sensors placed on hand 11.

[0038] [Configuration of two sets of optical sensors] Figure 3 is a schematic diagram showing how two sets of optical sensors are arranged on the hand 11 of the transport robot 10. As shown in Figure 3, two sets of optical sensors are arranged at the tip of the hand 11: a first light-emitting unit 21E and a first light-receiving unit 21R (hereinafter sometimes referred to as "first sensor 21") and a second light-emitting unit 22E and a second light-receiving unit 22R (hereinafter sometimes referred to as "second sensor 22").

[0039] The first light-emitting unit 21E is positioned at the tip (tip side) of the hand 11 and emits the first light 21L toward the base end of the hand 11, spanning the central spatial region at the tip of the hand 11.

[0040] The first light-receiving unit 21R is positioned to correspond to the first light-emitting unit 21E. The first light-receiving unit 21R is positioned on the base end side of the hand 11, straddling the central spatial region at the tip of the hand 11, relative to the first light-emitting unit 21E which is located at the tip of the hand 11, and is capable of receiving the first light 21L emitted by the first light-emitting unit 21E.

[0041] The second light-emitting unit 22E is positioned at the tip (tip side) of the hand 11, facing the first light-emitting unit 21E through the central spatial region at the tip of the hand 11. The second light-emitting unit 22E projects a second light 22L toward the base end of the hand 11, straddling the central spatial region at the tip of the hand 11.

[0042] The second light-receiving unit 22R is positioned to correspond to the second light-emitting unit 22E. The second light-receiving unit 22R is positioned on the base end side of the hand 11, straddling the central spatial region at the tip of the hand 11, relative to the second light-emitting unit 22E which is located at the tip of the hand 11, and is capable of receiving the second light 22L emitted by the second light-emitting unit 22E.

[0043] The first light 21L, emitted from the first light-emitting unit 21E and received by the first light-receiving unit 21R, has a first optical axis 21AX, and the second light 22L, emitted from the second light-emitting unit 22E and received by the second light-receiving unit 22R, has a second optical axis 22AX. The optical axis intersection point PX, where the first optical axis 21AX and the second optical axis 22AX intersect, is located in the central spatial region at the tip of the hand 11.

[0044] Thus, two sets of optical sensors (first sensor 21 and second sensor 22) are positioned at the tip of the hand 11, and the information detected by the first sensor 21 and second sensor 22 is monitored (acquired) by the sensor monitoring device 20.

[0045] [Configuration of the robot teaching device] Figure 4 is a functional block diagram showing the functions of a robot teaching device 100 according to one embodiment of the present invention. As shown in Figure 4, the robot teaching device 100 has a functional configuration comprising a robot control unit 110, a light reception amount distribution generation unit 120, a search unit 130, a landmark position calculation unit 140, and a target position calculation unit 150, and controls the operation of the transport robot 10 (hand 11) while monitoring information detected by the first sensor 21 and the second sensor 22.

[0046] Of these functions, the robot control unit 110 is a function of the robot control device 30. The light reception distribution generation unit 120, the search unit 130, the landmark position calculation unit 140, and the target position calculation unit 150 may all be provided in either the sensor monitoring device 20, which monitors information detected by the first sensor 21 and the second sensor 22, or the robot control device 30, or the functions may be distributed between the sensor monitoring device 20 and the robot control device 30. Furthermore, some or all of the functions may be provided in other information processing devices other than the sensor monitoring device 20 and the robot control device 30, in cooperation with the sensor monitoring device 20 and the robot control device 30.

[0047] The robot control unit 110 controls the operation of the transport robot 10. For example, a first sensor 21 and a second sensor 22 are located at the tip of the hand 11 of the transport robot 10, and the robot control unit 110 controls the operation of the transport robot 10 based on the information detected by the first sensor 21 and the second sensor 22.

[0048] The light-receiving amount distribution generation unit 120 generates a first light-receiving amount distribution based on the first light-receiving amount received by the first light-receiving unit 21R, and a second light-receiving amount distribution based on the second light-receiving amount received by the second light-receiving unit 22R, along the trajectory of the optical axis intersection point PX where the first optical axis 21AX and the second optical axis 22AX intersect, while the transport robot 10 is moved by the robot control unit 110.

[0049] For example, the light reception distribution generation unit 120 rotates (θ-axis) or moves forward (X-axis) the transport robot 10 (hand 11) by the robot control unit 110, records the first light reception amount received by the first light receiving unit 21R and the second light reception amount received by the second light receiving unit 22R, and generates the first light reception distribution and the second light reception distribution in the trajectory of the optical axis intersection point PX.

[0050] The search unit 130 searches for a light-shielding point where at least a portion of the first light 21L received by the first light-receiving unit 21R and at least a portion of the second light 22L received by the second light-receiving unit 22R are blocked by a predetermined marker, based on the first light-receiving distribution and the second light-receiving distribution generated by the light-receiving distribution generation unit 120.

[0051] The designated marker may be, for example, one of the three pins located on the stage S, and the light-shielding point refers to the position (including the orientation) of the transport robot 10 (hand 11) where the first light 21L emitted from the first light-emitting unit 21E and the second light 22L emitted from the second light-emitting unit 22E are shielded by the pin, resulting in a light-shielding state.

[0052] Here, the light-shielding state is not limited to a state in which the first light 21L emitted from the first light-emitting unit 21E and the second light 22L emitted from the second light-emitting unit 22E are completely blocked by the pin. For example, 50% of the first light 21L emitted from the first light-emitting unit 21E and the second light 22L emitted from the second light-emitting unit 22E may be used as a threshold, and the amount of light received by the first light-receiving unit 21R and the second light-receiving unit 22R may fall below this threshold. This allows for appropriate determination of a light-shielding state in which the first light 21L emitted from the first light-emitting unit 21E and the second light 22L emitted from the second light-emitting unit 22E are blocked by the pin, even if complete light shielding is not achieved due to, for example, light diffraction.

[0053] Figure 5 shows the process of the transport robot 10 (hand 11) moving towards pin P1 located on stage S while being rotated (θ axis) and moved forward (X axis) by the robot control unit 110. For example, when the transport robot 10 (hand 11) is near pin P1 located on stage S, the first light-receiving unit 21R records the first light-receiving amount and the second light-receiving amount 22R records the first light-receiving amount and generates the first light-receiving amount distribution and the second light-receiving amount distribution.

[0054] The three pins P1 to P3 may be cylindrical, conical, or truncated cone-shaped, and are arranged at equal intervals with respect to the center position P0 of the stage S, which is the target position for transporting and placing the wafer W. Their relative positions are known in advance.

[0055] Figure 6 shows the trajectories T1-T5 of the optical axis intersection point PX near pin P1 when generating the first and second light reception distributions. As shown in Figure 6, the transport robot 10 (hand 11) moves forward towards pin P1 at different angles, passing through pin P1.

[0056] Specifically, the robot control unit 110 positions the transport robot 10 (hand 11) in front of the pin P1, rotates the transport robot 10 (hand 11) (on the θ axis), and moves it forward in a direction approaching the pin P1 to pass through it (trajectory T1). Subsequently, the robot control unit 110 moves the transport robot 10 (hand 11) backward to the front of the pin P1, rotates the transport robot 10 (hand 11) again (on the θ axis), and moves it forward again in a direction approaching the pin P1 to pass through it (trajectory T2). After that, the robot control unit 110 moves the transport robot 10 (hand 11) backward to the front of the pin P1 and repeats the operation of moving the transport robot 10 (hand 11) in the same way (trajectories T3-T5).

[0057] During the period in which the transport robot 10 (hand 11) is moving, the light reception distribution generation unit 120 records the first light reception amount received by the first light receiving unit 21R and the second light reception amount received by the second light receiving unit 22R, and generates a first light reception distribution based on the first light reception amount and a second light reception distribution based on the second light reception amount for the trajectory T1 to T5 of the optical axis intersection point PX.

[0058] Figure 7 shows the first light reception distribution L10 based on the first light reception amount and the second light reception distribution L20 based on the second light reception amount for the trajectory T1 to T5 of the optical axis intersection point PX shown in Figure 6. As shown in Figure 7, corresponding to the trajectory T1 to T5 of the optical axis intersection point PX shown in Figure 6, light reception distributions L11 to L15 are generated as the first light reception distribution L10, and light reception distributions L21 to L25 are generated as the second light reception distribution L20.

[0059] For example, the amount of light received by the first light receiving unit 21R changes depending on whether the first light 21L emitted from the first light emitting unit 21E is not blocked by the pin P1, whether a portion of it is blocked by the pin P1, and whether it is blocked by the pin P1 (H level, M level, and L level).

[0060] In this document, the amount of light received by the first light-receiving unit 21R is schematically shown as "H" level, "M" level, and "L" level, but it is not limited to these three levels and may be shown as the actual amount of light received by the first light-receiving unit 21R.

[0061] Similarly, the amount of light received by the second light receiving unit 22R for the second light 22L emitted from the second light emitting unit 22E also changes (H level, M level, and L level).

[0062] Figure 8 shows how the system identifies positions in the first light-receiving distribution L10 and the second light-receiving distribution L20 shown in Figure 7 where a predetermined light-shielding state occurs. As shown in Figure 8, the search unit 130 plots a light-shielding position A (first range) in the first light-receiving distribution L10 where at least a portion of the first light 21L received by the first light-receiving unit 21R by pin P1 is shielded, and plots a light-shielding position B (second range) in the second light-receiving distribution L20 where at least a portion of the second light 22L received by the second light-receiving unit 22R by pin P1 is shielded.

[0063] For example, the search unit 130 may plot the position in the first light reception distribution L10 where the amount of light received by the first light receiving unit 21R is 50% of the first light 21L emitted from the first light emitting unit 21E as shading position A, and plot the position in the second light reception distribution L20 where the amount of light received by the second light receiving unit 22R is 50% of the second light 22L emitted from the second light emitting unit 22E as shading position B. These are then superimposed to show the shading position distribution L30.

[0064] The position where shading position A and shading position B overlap in the shading position distribution L30 can be determined by pin P1 to be a shading point where both a portion (50%) of the first light 21L received by the first light receiving unit 21R and a portion (50%) of the second light 22L received by the second light receiving unit 22R are shaded.

[0065] In this way, the search unit 130 searches for a light-shielding point in which at least a portion of the first light 21L received by the first light-receiving unit 21R and at least a portion of the second light 22L received by the second light-receiving unit 22R are shielded by the pin P1, based on the first light-receiving distribution L10 and the second light-receiving distribution L20 generated by the light-receiving distribution generation unit 120.

[0066] The search unit 130 was searching for a shading point where shading position A and shading position B in the shading position distribution L30 overlap. However, if shading position A and shading position B do not completely overlap, the shading point may be the position midway between shading position A and shading position B, where the distance between them is minimized, or the shading point may be searched for with even higher precision.

[0067] Figure 9 shows how the shading points are searched for with even higher precision. As shown in Figure 9, the detailed search area DA is set to include the range where the distance between shading position A and shading position B in the shading position distribution L30 is minimized. Here, the detailed search area DA is set to include a range where a portion (e.g., 50%) of the first light 21L (second light 22L) is shaded by pin P1 (a predetermined marker) and the amount of light received by the first light receiving unit 21R (second light receiving unit 22R) is shaded, and also includes a shading point where both a portion (50%) of the first light 21L received by the first light receiving unit 21R and a portion (50%) of the second light 22L received by the second light receiving unit 22R are shaded.

[0068] The detailed search area DA may be set by, for example, pre-dividing the area to be searched near pin P1 into grid-like ranges and selecting the range where the distance between shading position A and shading position B is minimized.

[0069] In the detailed search area DA, for example, by further subdividing the trajectory T1 to T5 of the optical axis intersection point PX shown in Figure 6, the robot control unit 110 rotates (θ axis) or moves the transport robot 10 (hand 11) forward (X axis), while recording the first light-receiving amount received by the first light-receiving unit 21R and the second light-receiving amount received by the second light-receiving unit 22R, thereby generating the first light-receiving amount distribution L10 and the second light-receiving amount distribution L20.

[0070] In other words, the search unit 130 can plot the light-shielding positions A and B in more detail within the detailed search area DA, and can search for light-shielding points where light-shielding positions A and B overlap, or where the distance between light-shielding positions A and B is even smaller.

[0071] Returning to the explanation of Figure 4, the marker position calculation unit 140 calculates the position of a predetermined marker based on the position of the transport robot 10 at the light-shielding point searched by the search unit 130. For example, based on the position of the transport robot 10 at the light-shielding point, the marker position calculation unit 140 determines the position of the contact point between the first light 21L (first optical axis 21AX) and the second light 22L (second optical axis 22AX) and the outer peripheral surface of the pin P1, and calculates the center position of the pin P1 based on the position of the connection point.

[0072] Figure 10 shows the process of calculating the center position P10 of pin P1. As shown in Figure 10, the optical axis intersection point PX of the first optical axis 21AX and the second optical axis 22AX is the light-shielding point found by the search unit 130, and the points of contact between the first light 21L (first optical axis 21AX) and the second light 22L (second optical axis 22AX) and the outer surface of pin P1 are points P11 and P12, respectively.

[0073] The marker position calculation unit 140 determines the positions of points P11 and P12 on the outer periphery of pin P1 (robot coordinate system) based on the position of the transport robot 10 at the light-shielding point. Then, since the pin P1 has a circular shape (cross-section) and the radius of this shape (circle) is known in advance, the marker position calculation unit 140 calculates the center position P10 of the circular shape (cross-section) of pin P1 based on the positions of points P11 and P12 on the circumference.

[0074] The target position calculation unit 150 calculates the target position for transporting a flat object based on the position of a predetermined marker calculated by the marker position calculation unit 140. For example, since the positional relationship between the center position P10 of pin P1 and the center position P0 of stage S (the target position for transporting and setting the wafer W) is known in advance, the target position calculation unit 150 calculates the target position for transporting and setting the wafer W (the center position P0 of stage S) based on the center position P10 of pin P1 calculated by the marker position calculation unit 140.

[0075] In this way, the robot teaching device 100 searches for light-shielding points based on the first light-receiving distribution L10 and the second light-receiving distribution L20, calculates the positions (robot coordinate system) of points P11 and P12 on the outer surface of pin P1 based on the position of the transport robot 10 at the light-shielding point, calculates the center position P10 of the circular shape (cross-section) of pin P1, and can calculate the target position (center position P0 of the stage S) with high accuracy. As a result, it is possible to generate high-precision teaching data after appropriately grasping the target position (center position P0 of the stage S), so that the wafer W can be placed with high accuracy at the center of the stage S.

[0076] [Method for calculating the target position when transporting a flat object] Next, we will explain in detail how to determine the position of pin P1 (center position P10) placed on stage S and calculate the target position (center position P0) for transporting the flat object.

[0077] Figure 11 is a flowchart showing the processing flow of a target position calculation method M100, which calculates the target position for transporting an object executed by a robot teaching device 100 according to one embodiment of the present invention. As shown in Figure 11, the target position calculation method M100 includes steps S101 to S110 and step S205, each step being mainly performed by a processor included in the sensor monitoring device 20, robot control device 30 and / or other information processing device that constitute the robot teaching device 100.

[0078] First, as explained using Figure 3, the hand 11 of the transport robot 10 is equipped with a first sensor 21 and a second sensor 22. Specifically, the tip of the hand 11 is equipped with a first light-emitting unit 21E that emits a first light 21L having a first optical axis 21AX, a second light-emitting unit 22E that emits a second light 22L having a second optical axis 22AX that intersects with the first optical axis 21AX (referred to as the optical axis intersection point PX), a first light-receiving unit 21R capable of receiving the first light 21L, and a second light-receiving unit 22R capable of receiving the second light 22L.

[0079] In step S101, the robot control unit 110 moves the transport robot 10 (hand 11) forward (in the X-axis direction). Specifically, the robot control unit 110 moves the hand 11 in a straight line towards the pin P1 located on the stage S.

[0080] In step S102, the robot teaching device 100 determines whether the first sensor 21 or the second sensor 22 is in a light-shielding state. Specifically, the robot teaching device 100 determines whether the amount of light received by the first light receiving unit 21R and the second light receiving unit 22R is less than a threshold (for example, 50% of the first light 21L emitted from the first light emitting unit 21E), thus determining whether it is in a light-shielding state.

[0081] If it is determined that the first sensor 21 or the second sensor 22 is in a light-shielding state ("Yes" in step S102), the process proceeds to step S103, and the robot control unit 110 stops the transport robot 10 (hand 11) from moving forward (in the X-axis direction). On the other hand, if it is determined that the first sensor 21 or the second sensor 22 is not in a light-shielding state ("No" in step S102), the process returns to step S101, and the robot control unit 110 continues the transport robot 10 (hand 11) from moving forward (in the X-axis direction).

[0082] In other words, the robot control unit 110 continues to move the transport robot 10 (hand 11) forward (in the X-axis direction) until it determines that the first sensor 21 or the second sensor 22 is in a light-shielding state.

[0083] If it is determined that the first sensor 21 is in a light-shielding state ("Yes" in step S104), the process proceeds to step S105, and the robot teaching device 100 determines that pin P1 is to the left in the forward direction of the optical axis intersection point PX.

[0084] If, in step S104, it is determined that the first sensor 21 is not in a light-shielding state ("No" in step S104), that is, if the second sensor 22 is in a light-shielding state, the process proceeds to step S205, and the robot teaching device 100 determines that pin P1 is to the right in the forward direction of the optical axis intersection point PX.

[0085] In step S106, the light reception amount distribution generation unit 120 generates a first light reception amount distribution L10 based on the first light reception amount received by the first light receiving unit 21R and a second light reception amount distribution L20 based on the second light reception amount received by the second light receiving unit 22R, while the robot control unit 110 moves the transport robot 10 (hand 11) based on the position of the pin P1 determined in step S105 or step S205.

[0086] Now, we will explain the process in step S106 in detail. Figure 12 is a flowchart showing the flow of the light reception distribution generation process in step S106. As shown in Figure 12, step S106 includes steps S1061 to S1067.

[0087] In step S1061, the light-receiving amount distribution generation unit 120 moves the transport robot 10 (hand 11) to the vicinity of pin P1 (towards the front) by the robot control unit 110, based on the position of pin P1 determined in step S105 or step S205.

[0088] In step S1062, the light-receiving amount distribution generation unit 120 rotates (sets) the transport robot 10 (hand 11) (θ axis) using the robot control unit 110. For example, as shown in Figure 6, the transport robot 10 (hand 11) may be rotated so as to form the trajectory T1 to T5 of the optical axis intersection point PX when the transport robot 10 (hand 11) is moved forward to pass through pin P1.

[0089] In step S1063, the light-receiving amount distribution generation unit 120 records the first and second light-receiving amounts received by the first light-receiving unit 21R and the second light-receiving unit 22R while the transport robot 10 (hand 11) is advanced by the robot control unit 110 to the search range in the X-axis direction. Here, the search range in the X-axis direction means that by advancing the transport robot 10 (hand 11), the optical axis intersection point PX passes through the area where at least pin P1 is located (from the front side to the back side of pin P1).

[0090] In step S1064, the light-receiving amount distribution generation unit 120 determines whether it has searched the search range (θ-axis direction) near pin P1. Specifically, as shown in Figure 6, it determines whether the optical axis intersection point PX has passed through and covered at least the range where pin P1 is located in the rotation direction (θ-axis direction) of the transport robot 10 (hand 11) (trajectory T1~T5).

[0091] If it is determined that the search range (in the θ-axis direction) near pin P1 has been searched ("Yes" in step S1064), the process proceeds to step S1065. If it is determined that the search range (in the θ-axis direction) near pin P1 has not been searched ("No" in step S1064), the process returns to step S1062. In other words, the process from steps S1062 to S1064 is repeated until it is determined that the search range (in the θ-axis direction) near pin P1 has been searched.

[0092] In step S1065, the light reception distribution generation unit 120 generates a first light reception distribution and a second light reception distribution in the trajectory of the optical axis intersection point PX within the search range, based on the first and second light reception amounts recorded in steps S1062 to S1064. Specifically, the light reception distribution generation unit 120 may generate a first light reception distribution L10 including light reception distributions L11 to L15, and a second light reception distribution L20 including light reception distributions L21 to L25, as shown in Figure 7.

[0093] In step S1066, the light-receiving amount distribution generation unit 120 determines whether the difference between the shading position in the first light-receiving amount distribution and the shading position in the second light-receiving amount distribution is less than or equal to a threshold. For example, as shown in Figure 8, the light-receiving amount distribution generation unit 120 may determine whether the difference between the shading position A where the amount of light received is 50% in the first light-receiving amount distribution L10 and the shading position B where the amount of light received is 50% in the second light-receiving amount distribution L20 is less than or equal to a threshold (whether there are any positions that are less than or equal to a threshold).

[0094] If it is determined that the difference between shading position A and shading position B is less than or equal to the threshold ("Yes" in step S1066), the light reception distribution generation process in step S106 is terminated. If it is determined that the difference between shading position A and shading position B is not less than or equal to the threshold ("No" in step S1066), the process proceeds to step S1067.

[0095] In step S1067, the light-receiving amount distribution generation unit 120 precisely sets the rotation angle of the θ axis and returns to the process in step S1062. Specifically, in the light-shielding position distribution L30 shown in Figure 8, if light-shielding position A and light-shielding position B are far apart (not below a threshold), the light-receiving amount distribution generation unit 120 precisely sets the rotation angle of the θ axis in order to improve the resolution of the first light-receiving amount distribution L10 and the second light-receiving amount distribution L20. For example, the rotation angle of the transport robot 10 (hand 11) may be set by the robot control unit 110 so as to traverse between each trajectory of the optical axis intersection point PX T1 to T5 as shown in Figure 6.

[0096] Returning to the explanation of Figure 11, in step S107, the search unit 130 searches for the position of the optical axis intersection that will be the shading point, based on the light reception amount distribution generated in step S106. Specifically, the search unit 130 searches for the position where shading position A and shading position B in the shading position distribution L30 shown in Figure 8 overlap as the shading point, but the shading point may be searched with even higher precision.

[0097] Here, we will explain in detail the process of step S107, which searches for light-shielding points with even higher precision. Figure 13 is a flowchart showing the flow of the search process in step S107. As shown in Figure 13, step S107 includes steps S1071 to S1073.

[0098] In step S1071, the interpolation unit (not shown) interpolates the first and second light reception distributions generated in step S106 (for example, steps S1061 to S1067).

[0099] Figure 14 schematically shows how the first light reception distribution L10 and the second light reception distribution L20 shown in Figure 7 are interpolated. As shown in Figure 14, the interpolation unit interpolates the first light reception distribution L10 and the second light reception distribution L20 to generate the first light reception distribution L10' and the second light reception distribution L20'.

[0100] The interpolation method used here may be linear interpolation, or it may be nonlinear interpolation such as polynomial regression or kernel regression. An appropriate interpolation method may be selected depending on the characteristics of the first light reception distribution L10 and the second light reception distribution L20.

[0101] In step S1072, the search unit 130 sets a detailed search area for shading points based on the first light reception distribution and the second light reception distribution. Specifically, the search unit 130 superimposes the first light reception distribution L10' and the second light reception distribution L20' generated by interpolation in step S1071 to set a detailed search area DA in the shading position distribution L30 as explained with reference to Figure 9.

[0102] In step S1073, the search unit 130 searches for light-shielding points in the detailed search area DA set in step S1072. As a specific example, as explained with reference to Figure 9, the search unit 130 may rotate (θ axis) or move forward (X axis) the transport robot 10 (hand 11) by the robot control unit 110, and search for light-shielding points based on light-shielding positions A and B that have been plotted in more detail in the detailed search area DA.

[0103] Furthermore, the search unit 130 may use methods to search for light-shielding points, such as a grid search that comprehensively (in a grid pattern) searches the set range between the X and θ axes, an optimization method using gradients that measures the amount of light received by slightly changing the X and θ axes and searches by moving in the direction in which the amount of light received increases, and an optimization method that does not use gradients, such as a genetic algorithm. Alternatively, a method may be used that combines a response surface, which generates a surface from the amount of light received in each grid-like range and calculates the position where the amount of light received is maximized from the surface, with the optimization methods described above.

[0104] Furthermore, response surfaces can include polynomials, neural networks, Kriging, and RBF (Radial Basis Function Network), and kernel regression and support vector regression are also known, which can be used to search for shading points.

[0105] Returning to the explanation of Figure 11, in step S108, the marker position calculation unit 140 obtains the positions of two points on the outer circumferential surface of pin P1 based on the position of the transport robot 10 at the light-shielding point searched in step S107. Specifically, as explained using Figure 10, the marker position calculation unit 140 calculates the positions of points P11 and P12 on the circumference based on the position (including orientation) of the transport robot 10 (hand 11) at the light-shielding point where both the first sensor 21 and the second sensor 22 are in a light-shielding state.

[0106] In step S109, the marker position calculation unit 140 calculates the center position of pin P1 based on the positions of two points on the outer surface of pin P1 calculated in step S108. Specifically, as explained with reference to Figure 10, the marker position calculation unit 140 calculates the center position P10 of pin P1 based on the positions of points P11 and P12 on the circumference.

[0107] In step S110, the target position calculation unit 150 calculates the center position (target position) of the stage S based on the center position P10 of the pin P1 calculated in step S109. Specifically, as explained using Figure 10, the target position calculation unit 150 has prior knowledge of the positional relationship between the position of the pin P1 and the center position P0 of the stage S (the target position where the wafer W is transported and placed), and therefore calculates the center position P0 of the stage S (the target position where the wafer W is transported and placed) based on the center position P10 of the pin P1.

[0108] As described above, according to the robot teaching device 100 and target position calculation method M100 according to one embodiment of the present invention, a first sensor 21 (first light-emitting unit 21E and first light-receiving unit 21R) and a second sensor 22 (second light-emitting unit 22E and second light-receiving unit 22R) are arranged on the hand 11 of the transport robot 10, and the light-receiving amount distribution generation unit 120 generates a first light-receiving amount distribution L10 and a second light-receiving amount distribution L20 in the trajectory of the optical axis intersection point PX while the transport robot 10 (hand 11) is moved by the robot control unit 110. The search unit 130 searches for a light-shielding point where both the first sensor 21 and the second sensor 22 are in a light-shielding state using pin P1, based on the first light-receiving amount distribution L10 and the second light-receiving amount distribution L20. The marker position calculation unit 140 calculates the center position P10 of pin P1 based on the position (including orientation) of the transport robot 10 at the light-shielding point, and the target position calculation unit 150 calculates the target position P0 (center position of the stage S) for transporting the wafer W based on the center position P10 of pin P1. As a result, the position of pin P1 can be searched with high accuracy, and the target position P0 for transporting the wafer W can be appropriately calculated based on the center position P10 of pin P1.

[0109] Furthermore, by interpolating the first and second light-receiving amounts between the trajectories of the optical axis intersection point PX to generate the first and second light-receiving amount distributions, and by setting a detailed search area DA, the position of pin P1 can be determined with higher accuracy, and as a result, the target position P0 for transporting the wafer W can be calculated more appropriately.

[0110] Here, for example, as explained using Figures 6 and 7, when generating the first light reception distribution L10 and the second light reception distribution L20 in the trajectory of the optical axis intersection point PX, the processing time is shortened by moving the transport robot 10 (hand 11) at high speed using the robot control unit 110. On the other hand, when searching for light-shielding points in detail in the detailed search area DA, the position of the light-shielding points is searched with high precision by moving the transport robot 10 (hand 11) at a low speed using the robot control unit 110.

[0111] In other words, by appropriately setting the speed at which the transport robot 10 (hand 11) is moved by the robot control unit 110, the time required for auto-teaching is reduced, the position of pin P1 is searched with high precision, and as a result, the target position P0 for transporting the wafer W can be calculated more appropriately.

[0112] In this embodiment, the light-receiving amount distribution generation unit 120 generated the first light-receiving amount distribution L10 and the second light-receiving amount distribution L20 along the trajectory of the optical axis intersection point PX while the robot control unit 110 moved the transport robot 10 (hand 11). However, the direction of movement (movement procedure) of the transport robot 10 (hand 11) is not limited to this. Any other direction of movement (movement procedure) is acceptable as long as the first light-receiving amount distribution L10 and the second light-receiving amount distribution L20 along the trajectory of the optical axis intersection point PX can be generated near pin P1.

[0113] Figure 15 shows another trajectory T6 of the optical axis intersection point PX near pin P1. As shown in Figure 15, the transport robot 10 (hand 11) moves toward the center position of pin P1 while orbiting it.

[0114] Furthermore, during the period in which the transport robot 10 (hand 11) is moving, the light reception distribution generation unit 120 may record the first light reception amount received by the first light receiving unit 21R and the second light reception amount received by the second light receiving unit 22R, and generate a first light reception distribution based on the first light reception amount and a second light reception distribution based on the second light reception amount in the trajectory T6 of the optical axis intersection point PX.

[0115] Furthermore, in this embodiment, the marker position calculation unit 140 determined the positions of points P11 and P12 on the outer peripheral side of the pin P1 based on the position of the transport robot 10 at the light-shielding point, and calculated the center position P10 of the circular shape (cross-section) of the pin P1. However, the method for calculating the center position P10 of the pin P1 is not limited to this.

[0116] Figure 16 is a schematic diagram illustrating another method for calculating the center position P10 of pin P1. As shown in Figure 16(A), the positions of points P11 and P12 on the outer periphery of pin P1 (robot coordinate system) are determined based on the position of the transport robot 10 at the light-shielding point on the front side of pin P1. Then, as shown in Figure 16(B), as the transport robot 10 continues to move forward, the positions of points P13 and P14 on the outer periphery of pin P1 (robot coordinate system) are determined based on the position of the transport robot 10 at the light-shielding point on the back side of pin P1.

[0117] As a result, the marker position calculation unit 140 can calculate the distance d between the position of the optical axis intersection point PX in the state shown in Figure 16(A) and the position of the optical axis intersection point PX in the state shown in Figure 16(B).

[0118] The marker position calculation unit 140 may calculate the center position P10 of pin P1 based on the diameter of pin P1 which is known in advance, the placement positions (mounting angles, etc.) of the first sensor 21 and the second sensor 22, and the theoretical and measured values ​​of the distance d. Furthermore, the center position P10 of pin P1 may be searched for and determined using an optimization method or the like.

[0119] In this embodiment, the center position P10 of pin P1, which is located on the stage S, was calculated using pin P1 as a predetermined marker. However, the predetermined marker is not limited to pin P1, and may be other pins, such as pin P2. Furthermore, if the relative positional relationship with the target position P0 (center position of the stage S) where the wafer W is transported is known, a pin other than the one located on the stage S may be used as the predetermined marker.

[0120] Furthermore, in this embodiment, the first sensor 21 and the second sensor 22 were arranged with the first light-emitting unit 21E and the second light-emitting unit 22E on the tip side and the first light-receiving unit 21R and the second light-receiving unit 22R on the base end side of the tip of the hand 11, respectively. However, the arrangement of the light-emitting and light-receiving units is not limited to these.

[0121] Figure 17 schematically shows how two sets of optical sensors are arranged on the hand 11 of the transport robot 10 in a different manner. As shown in Figure 17, the first light receiving unit 21R and the second light receiving unit 22R are arranged at the tip end of the hand 11, and the first light emitting unit 21E and the second light emitting unit 22E are arranged at the base end.

[0122] Furthermore, while the first sensor 21 and second sensor 22 were arranged on the hand 11, consisting of a first light-emitting unit 21E and a first light-receiving unit 21R, and a second light-emitting unit 22E and a second light-receiving unit 22R, for example, the sensor set containing the first sensor 21 and the second sensor 22 may be held or attached to the hand 11.

[0123] Furthermore, although optical sensors were used as the first sensor 21 and the second sensor 22 in this embodiment, contact sensors may also be used, for example. For example, sensing units may be provided at positions corresponding to the first optical axis 21AX and the second optical axis 22AX, and the position (including orientation) of the transport robot 10 where both of these contact the pin P1 (corresponding to the light-shielding point) may be searched.

[0124] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The elements, arrangement, materials, conditions, shapes, and sizes of the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, it is possible to partially substitute or combine the configurations shown in different embodiments. [Explanation of Symbols]

[0125] 1...Transport robot system, 10...Transport robot, 11...Hand, 20...Sensor monitoring device, 30...Robot control device, 40...Operating equipment, 100...Robot teaching device, 110...Robot control unit, 120...Light reception amount distribution generation unit, 130...Search unit, 140...Marker position calculation unit, 150...Target position calculation unit, S, S1~S3...Stage, W...Wafer, WS...Workspace, 21, 22...Sensor, 21E, 22E...Light emission unit, 21R, 22R...Light receiving unit, 21L, 22L...Light, 21AX, 22AX...Optical axis, PX...Optical axis intersection, P0...Inside stage S Center position, P1~P3…Pins, P10…Center position of pin P1, P11, P12, P13, P14…Points on the outer periphery of pin P1, T1~T6…Trajectory, L10~L15, L20~L25, L10', L20'…Light reception amount distribution, L30…Shaded position distribution, A, B…Shaded positions, DA…Detailed search area, M100…Target position calculation method, S101~S110, S205…Each step of target position calculation method M100, Steps S1061~S1067…Details of step S106, Steps S1071~S1073…Details of step S107, d…Distance

Claims

1. A robot teaching device for a transport robot that transports flat objects, A robot control unit that controls the operation of the transport robot, The transport robot is equipped with a first light-emitting unit that emits a first light having a first optical axis, and a second light-emitting unit that emits a second light having a second optical axis intersecting the first optical axis, A first light-receiving unit capable of receiving the first light and a second light-receiving unit capable of receiving the second light, A light-receiving amount distribution generation unit generates a first light-receiving amount distribution based on the first light-receiving amount received by the first light-receiving unit and a second light-receiving amount distribution based on the second light-receiving amount received by the second light-receiving unit, while the transport robot is moved by the robot control unit. A search unit searches for a light-shielding point where, based on the first light-receiving distribution and the second light-receiving distribution generated by the light-receiving distribution generation unit, at least a portion of the first light received by the first light-receiving unit and at least a portion of the second light received by the second light-receiving unit are blocked by a predetermined marker. A marker position calculation unit calculates the position of a predetermined marker based on the position of the transport robot at the light-shielding point searched by the search unit, The system includes a target position calculation unit that calculates a target position for transporting the flat object based on the position of a predetermined marker calculated by the marker position calculation unit, and a target position calculation unit that calculates a target position for transporting the flat object. Robot teaching device.

2. The search unit searches for the shading point based on a first range in the first light-receiving distribution in which at least a portion of the first light received by the first light-receiving unit is shaded by the predetermined marker, and a second range in the second light-receiving distribution in which at least a portion of the second light received by the second light-receiving unit is shaded by the predetermined marker. The robot teaching device according to claim 1.

3. The search unit searches for the light-shielding point based on the overlapping range of the first range and the second range. The robot teaching device according to claim 2.

4. The system further includes an interpolation unit that interpolates the first and second light-receiving amounts between the trajectories of the optical axis intersections, and generates a first light-receiving amount distribution based on the first light-receiving amount and a second light-receiving amount distribution based on the second light-receiving amount between the trajectories of the optical axis intersections. A robot teaching device according to any one of claims 1 to 3.

5. The statement that at least a portion of the first light received by the first light receiving unit is blocked by the predetermined mark, or that at least a portion of the second light received by the second light receiving unit is blocked by the predetermined mark, includes a state in which the amount of the first light received by the first light receiving unit, or the amount of the second light received by the second light receiving unit, is below a threshold. The robot teaching device according to claim 1.

6. The aforementioned predetermined marker is a pin on which the flat object is placed. The robot teaching device according to claim 1.

7. A target position calculation method for calculating the target position for transporting a flat object, which is performed by a robot teaching device of a transport robot that transports a flat object, The transport robot is equipped with a first light-emitting unit that emits a first light having a first optical axis, a second light-emitting unit that emits a second light having a second optical axis intersecting the first optical axis, a first light-receiving unit capable of receiving the first light, and a second light-receiving unit capable of receiving the second light. A robot control step that controls the operation of the transport robot, In the robot control step, while moving the transport robot, a light-receiving amount distribution generation step is performed to generate a first light-receiving amount distribution based on a first light-receiving amount received by the first light-receiving unit and a second light-receiving amount distribution based on a second light-receiving amount received by the second light-receiving unit, in the trajectory of the optical axis intersection point where the first optical axis and the second optical axis intersect. A search step to search for a light-shielding point where, based on the first light-receiving distribution and the second light-receiving distribution generated in the light-receiving distribution generation step, at least a portion of the first light received by the first light-receiving unit and at least a portion of the second light received by the second light-receiving unit are blocked by a predetermined marker, A marker position calculation step, which calculates the position of the predetermined marker based on the position of the transport robot at the light-shielding point searched in the search step, A target position calculation step includes calculating the target position based on the position of the predetermined marker calculated in the marker position calculation step, Target position calculation method.

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