Robot control device, position calculation method, and sensor device used for method

Abstract

To provide a robot control device, a position calculation method, and a sensor device used for the method, which can properly calculate a position of an object detected by a sensor held by a robot by taking an inclination of the sensor into consideration.SOLUTION: A robot control device 100 includes: first detection means 120 which detects an object E by object sensors 21, 22 held by a robot 10 by operating the robot 10 by robot control means 110; second detection means 130 which detects a plane F including the object E by a sensor group constituted of a plurality of sensors 21, 21A, 21B, 22, 22A, 22B which is held by the robot 10; and object position calculation means 140 which calculates a position of the object E detected by the object sensors 21, 22 on the basis of each distance up to the plane F detected by each of the plurality of sensors in the sensor group and positional information between the object sensors 21 and 22 and the sensor group.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a robot control device, a position calculation method, and a sensor device used therein. [Background technology]

[0002] In recent years, many robots have become widespread in the industrial world. These robots are used, for example, for assembling, welding, and transporting electronic and mechanical parts, thereby improving the efficiency and automation of factory production lines.

[0003] Transfer robots used in semiconductor manufacturing equipment to transport wafers require teaching to transport the wafers to the appropriate position, but the accuracy of this teaching depends on the knowledge and skill of the operator. Also, there are cases where space saving is required to the extent that there is not enough space for the operator to work, so efforts are being made to automate the teaching process.

[0004] For example, Patent Document 1 discloses a technique in which a substrate-type jig equipped with three optical sensors is held by a hand, and the substrate holding part is rotated to form a circular rotation locus of a mark provided in advance on the substrate holding part, and the relative position of the hand to the substrate holding part in a plan view is calculated based on the relative positions of the hand to the rotation locus obtained from each of the three optical sensors.

[0005] As described above, a technique is known in which three optical sensors are used to grasp the positional relationship between the robot and the target position, as well as the surrounding environment such as obstacles, and to appropriately transport an object to the target position. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-148237 Summary of the Invention [Problem to be solved by the invention]

[0007] However, Patent Document 1 does not take into consideration the tilt of the three optical sensors when the substrate-type jig on which the three optical sensors are provided is held by a hand. For example, various factors can be considered, such as when the hand holding the substrate-type jig is not horizontal, when the substrate-type jig on which the optical sensors are provided is not a uniform plane, when the hand tilts due to placing the substrate-type jig on the hand, and when the optical sensors are attached to the substrate-type jig at an angle.

[0008] Therefore, an object of the present invention is to provide a robot control device, a position calculation method, and a sensor device used therein that can appropriately calculate the position of an object detected by a sensor held by the robot, taking into account the inclination of the sensor. [Means for solving the problem]

[0009] A robot control device according to one embodiment of the present invention is a robot control device that controls the operation of a robot, and includes: a robot control means for operating the robot; a first detection means for detecting an object using an object sensor held by the robot by operating the robot using the robot control means; a second detection means for detecting a plane containing the object using a sensor group consisting of a plurality of sensors held by the robot by operating the robot using the robot control means; and an object position calculation means for calculating the position of the object detected by the object sensor based on the distances to the plane detected by each of the plurality of sensors in the sensor group and position information of the object sensor and the sensor group.

[0010] According to this aspect, the first detection means detects an object using an object sensor held by the robot, and the second detection means detects a plane containing the object using a sensor group consisting of multiple sensors held by the robot. The object position calculation means calculates the position of the object detected by the object sensor based on the distances to the plane detected by each of the multiple sensors in the sensor group and position information between the object sensor and the sensor group. This makes it possible to appropriately calculate the position of the object detected by the sensor, taking into account the inclination of the sensor held by the robot. As a result, the object can be transported with high accuracy to a target position calculated based on the position of the object.

[0011] In the above aspect, the target position calculation means may include a detection position calculation means for calculating the detection position of the target detected by the target sensor, a tilt calculation means for calculating the tilt of the target sensor relative to the plane based on the distances to the plane detected by each of the multiple sensors in the sensor group and the distances between the multiple sensors in the sensor group, and a correction means for correcting the detection position of the target based on the tilt of the target sensor.

[0012] According to this aspect, the tilt calculation means calculates the tilt of the target sensor based on the distances to the plane detected by each of the multiple sensors in the sensor group and the distances between the multiple sensors, and the correction means corrects the detection position of the target detected by the target sensor calculated by the detection position calculation means based on the tilt of the target sensor. This makes it possible to calculate the position of the target detected by the sensor with high accuracy, taking the tilt of the sensor into consideration.

[0013] In the above aspect, the subject sensor and the plurality of sensors in the sensor group may be arranged on the same plane.

[0014] According to this aspect, the inter-sensor distance between the target sensor and the multiple sensors in the sensor group is known in advance, eliminating the need for processing such as measuring the inter-sensor distance, and therefore the inclination of the target sensor can be easily calculated.

[0015] In the above aspect, the sensor group may include two sensor groups each consisting of a pair of a first sensor and a second sensor corresponding to the first sensor.

[0016] According to this aspect, the tilt of the area in a pair of sensor groups can be calculated from the difference in distances from each sensor in the pair of sensor groups to the plane, and further, by including two pairs of sensor groups, the direction of tilt in the area in which the sensor groups are arranged can be properly grasped.

[0017] In the above embodiment, the two pairs of sensor groups may be arranged so as to be orthogonal to each other.

[0018] According to this aspect, the two pairs of sensor groups are arranged so as to be perpendicular to each other, and therefore it is possible to more appropriately grasp the tilt direction in the area in which the sensor groups are arranged.

[0019] In the above embodiment, the subject sensor may function as one sensor among multiple sensors in the sensor group.

[0020] According to this aspect, the target sensor functions as one sensor among a plurality of sensors in the sensor group, thereby making it possible to reduce the number of sensors.

[0021] In the above aspect, the subject sensor may be provided as at least a first subject sensor and a second subject sensor, and the sensor group may be provided as at least a first sensor group and a second sensor group corresponding to the first subject sensor and the second subject sensor, respectively.

[0022] According to this aspect, since a sensor group is provided corresponding to each of the at least two object sensors, the tilt of each object sensor can be calculated with high accuracy. As a result, the position of the object detected by each object sensor can be calculated with high accuracy, taking into account the tilt of each object sensor.

[0023] In the above aspect, the distance between each of the multiple sensors in the first sensor group and the sensor for the first object may be smaller than the distance between either of the multiple sensors in the first sensor group or the sensor for the first object and either of the multiple sensors in the second sensor group or the sensor for the second object that is closest to that sensor.

[0024] According to this aspect, since a sensor group is provided near each of the at least two object sensors, the tilt of each object sensor can be calculated with higher accuracy. As a result, the position of the object detected by each object sensor can be calculated with higher accuracy, taking into account the tilt of each object sensor.

[0025] In the above aspect, the target sensor and the plurality of sensors in the sensor group may be provided in a sensor device held by the robot.

[0026] According to this aspect, the position of the target can be calculated with high accuracy by using the sensor device and taking into account the inclination of the target sensor provided in the sensor device.

[0027] A position calculation method according to one aspect of the present invention is a position calculation method for calculating the position of an object executed by a robot control device that controls the operation of a robot, and includes: a robot control step for operating the robot; a first detection step for detecting an object using an object sensor held by the robot by operating the robot in the robot control step; a second detection step for detecting a plane containing the object using a sensor group consisting of multiple sensors held by the robot by operating the robot in the robot control step; and an object position calculation step for calculating the position of the object detected by the object sensor based on the distances to the plane detected by each of the multiple sensors in the sensor group and position information of the object sensor and the sensor group.

[0028] According to this aspect, in the first detection step, an object is detected by an object sensor held by the robot, and in the second detection step, a plane including the object is detected by a sensor group consisting of multiple sensors held by the robot. Then, in the object position calculation step, the position of the object detected by the object sensor is calculated based on the distances to the plane detected by each of the multiple sensors in the sensor group and the position information of the object sensor and the sensor group. This makes it possible to appropriately calculate the position of the object detected by the sensor taking into account the inclination of the sensor held by the robot. As a result, the object can be transported with high accuracy to a target position calculated based on the position of the object.

[0029] A sensor device according to one embodiment of the present invention is a sensor device used in a position calculation method for calculating the position of an object executed by a robot control device that controls the operation of a robot, and includes an object sensor that detects the object and a sensor group consisting of multiple sensors that detect a plane containing the object. The position calculation method includes a robot control step for operating the robot, a first detection step for operating the robot in the robot control step to detect the object using the object sensor of the sensor device held by the robot, a second detection step for operating the robot in the robot control step to detect the plane containing the object using the sensor group consisting of the multiple sensors of the sensor device held by the robot, and an object position calculation step for calculating the position of the object detected by the object sensor based on the distances to the plane detected by each of the multiple sensors in the sensor group and position information of the object sensor and the sensor group.

[0030] According to this aspect, in the first detection step, an object is detected by an object sensor held by the robot, and in the second detection step, a plane including the object is detected by a sensor group consisting of multiple sensors held by the robot. Then, in the object position calculation step, the position of the object detected by the object sensor is calculated based on the distances to the plane detected by each of the multiple sensors in the sensor group and the position information of the object sensor and the sensor group. This makes it possible to appropriately calculate the position of the object detected by the sensor taking into account the inclination of the sensor held by the robot. As a result, the object can be transported with high accuracy to a target position calculated based on the position of the object. [Effects of the Invention]

[0031] According to the present invention, it is possible to provide a robot control device, a position calculation method, and a sensor device used therein that can appropriately calculate the position of an object detected by a sensor held by a robot, taking into account the inclination of the sensor. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a schematic diagram showing the system configuration of a transfer robot system 1 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing how the transfer robot 10 operates in a clean environment. [Figure 3] 2 is a diagram showing the configuration of a sensor device 20 held by a hand 11 in a transfer robot 10. FIG. [Figure 4] 1 is a functional block diagram showing each function of a robot control device 100 according to an embodiment of the present invention. [Figure 5] 1 is a diagram showing a state in which the sensor device 20 is held by the hand 11 of the transport robot 10 and moves toward the stage S. FIG. [Figure 6] 10 is a diagram showing how an edge E of a stage S is detected by an optical sensor provided in a sensor device 20. FIG. [Figure 7] 10 is a diagram showing how the distances to the plane F of the stage S are detected by two optical sensors provided in the sensor device 20. FIG. [Figure 8] 1 is a flowchart showing the flow of processing in a position calculation method M100 for calculating the position of an object, which is executed by a robot control device 100 according to an embodiment of the present invention. [Figure 9] 10 is a diagram showing another configuration of the sensor device 20. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the embodiment described below is merely a specific example for carrying out the present invention and is not intended to limit the present invention. Furthermore, to facilitate understanding of the description, the same components in each drawing will be assigned the same reference numerals as much as possible, and duplicate descriptions may be omitted.

[0034] <One embodiment> [Transport robot system configuration] 1 is a schematic diagram showing the system configuration of a transfer robot system 1 according to an embodiment of the present invention. As shown in FIG. 1, the transfer robot system 1 includes a robot control device 100 and a transfer robot 10.

[0035] The transfer robot 10 is, for example, a horizontal articulated robot intended for wafer transfer, and is a clean transfer robot used for transfer in clean environments in the manufacturing of semiconductor devices and flat panel displays, the medical and food industries, etc. In this embodiment, the transfer robot 10 is, for example, of a two-axis or three-axis cylindrical coordinate type, and has a hand 11 as an end effector, and the hand 11 is used to hold and transfer a wafer (object).

[0036] The robot control device 100 is a device that controls the operation of the transport robot 10. For example, the robot control device 100 is connected to an operating device (not shown) such as a teach pendant, and can acquire operation instruction information input to the operating device. Based on the operation instruction information, the robot control device 100 starts and stops the transport robot 10, and operates each axis of the transport robot 10 as well as the arms and hands 11 to pick up, transport, and set down an object.

[0037] An operating device such as a teach pendant receives input from an operator regarding operation instruction information for the transport robot 10, which is related to the transport work of transporting an object. Typically, an operator uses an operating device such as a teach pendant to input appropriate instruction information, for example, for starting and stopping the transport robot 10, further for setting the transport robot 10, operating the arms and hands 11, and registering teaching points.

[0038] Regarding the registration of teaching points, the operator may sequentially register teaching points on the movement path while operating the transport robot 10 using an operating device such as a teach pendant, or the teaching points may be automatically registered by automatic teaching. Automatic teaching is effective, for example, in an environment or situation where there is not enough space (work space) for the operator to enter.

[0039] [Wafer transport] 2 is a schematic diagram showing the operation of a transfer robot 10 in a clean environment. As shown in Fig. 2, the transfer robot 10 installed in a work space WS transfers a wafer W held by a hand 11 to each of stages S1 to S3 (hereinafter, sometimes collectively referred to as "stage S") in a process chamber in a vacuum environment.

[0040] Specifically, the transfer robot 10 operates the arms and hands 11 based on operation instruction information from the robot control device 100 to remove the wafer W and transfer it to the stage S as the transfer destination.

[0041] Here, the target position to which the wafer W is transferred and placed is, for example, the center of the stage S. It is preferable to place the wafer W at the center of the stage S with high accuracy. The robot control device 100 actually transfers the wafer W and places it at the target position, that is, the center of the stage S, based on the teaching data. In this case, the robot control device 100 can generate highly accurate teaching data by detecting the edge of the stage S and appropriately determining the position of the stage S. As a result, the wafer W can be placed at the center of the stage S with high accuracy. In other words, it is important to appropriately determine the position of the edge of the stage S. Below, a method for detecting the edge of the stage S using a sensor device and determining its position will be described.

[0042] [Configuration of the sensor device] The sensor device is a device that includes an optical sensor and can be grasped, held, or attached to the hand 11 of the transport robot 10. Fig. 3 is a diagram showing the configuration of the sensor device 20 held by the hand 11 of the transport robot 10. As shown in Fig. 3, the sensor device 20 has two optical sensors 21 and 22, with optical sensors 21A and 21B located near the optical sensor 21 and optical sensors 22A and 22B located near the optical sensor 22.

[0043] Each of the optical sensors 21, 21A, 21B, 22, 22A, and 22B is attached to the rear surface of the sensor device 20 and is a reflective optical sensor that can calculate distance by receiving reflected light of light emitted downward from a light source.

[0044] Since the sensor device 20 is placed on the hand 11, the optical sensors 21, 21A, 21B, 22, 22A, and 22B are attached near the outer periphery (edge) of the sensor device 20 so that the light emitted downward is not blocked by the hand 11. In other words, the hand 11 holds the sensor device 20 so as to avoid the area where the optical sensors 21, 21A, 21B, 22, 22A, and 22B are attached.

[0045] The sensor device 20 may also be equipped with a control unit and a communication unit, and each of the optical sensors 21, 21A, 21B, 22, 22A, and 22B may control the light emitted from the light source, receive reflected light, and notify information about it, for example, to the robot control device 100.

[0046] For example, when the sensor device 20 held by the hand 11 passes above the stage S, the optical sensor 21 (first object sensor) detects the edge (object) of the stage S. The optical sensors 21A and 21B, together with the optical sensor 21, detect the plane of the stage S to grasp the inclination of the optical sensor 21 (first sensor group).

[0047] The first sensor group is composed of three optical sensors 21, 21A, and 21B (optical sensor 21 also serves as an object sensor), which are arranged in two directions to grasp the inclination of optical sensor 21. Specifically, the arrangement direction of optical sensors 21 and 21A is perpendicular to the arrangement direction of optical sensors 21 and 21B. This makes it possible to grasp the inclination of optical sensor 21 in terms of the direction of optical sensor 21A relative to optical sensor 21 and the inclination of optical sensor 21B relative to optical sensor 21.

[0048] Furthermore, it is preferable that the distance between optical sensors 21 and 21A and the distance between optical sensors 21 and 21B are small, and are at least smaller than the distance from these optical sensors 21, 21A, and 21B to the second sensor group (three optical sensors 22, 22A, and 22B). This makes it possible to properly grasp the tilt of the local area of ​​sensor device 20 where optical sensor 21 is installed. The tilt will be described in detail later.

[0049] Similarly, optical sensor 22 (second object sensor) detects the edge (object) of stage S, and optical sensors 22A and 22B, together with optical sensor 22, determine the inclination of optical sensor 22 (second sensor group). The arrangement direction of optical sensors 22 and 22A is perpendicular to the arrangement direction of optical sensors 22 and 22B, and the distance between optical sensors 22 and 22A and the distance between optical sensors 22 and 22B is preferably short, and is at least shorter than the distance from these optical sensors 22, 22A, and 22B to the first sensor group (three optical sensors 21, 21A, and 21B). This allows the inclination of the local area of ​​sensor device 20 where optical sensor 22 is installed to be properly determined.

[0050] [Robot control device configuration] FIG. 4 is a functional block diagram showing each function of a robot control device 100 according to an embodiment of the present invention. As shown in FIG. 4, the robot control device 100 includes a robot control unit 110, a first detection unit 120, a second detection unit 130, and an object position calculation unit 140, and controls the operation of the transfer robot 10. While moving the hand 11 holding the sensor device 20, the robot control device 100 detects the edge (object) of the stage S using two optical sensors 21 and 22 (a first object sensor and a second object sensor), and detects the plane of the stage S using three optical sensors 21, 21A, and 21B (a first sensor group) and three optical sensors 22, 22A, and 22B (a second sensor group). Based on the detection results, the robot control device 100 determines the edge position of the stage S, taking into account the inclination of the two optical sensors 21 and 22.

[0051] 1, the robot control device 100 is connected to the transport robot 10, and further has many functions for performing various controls and processes based on operation instruction information from an operating device such as a teach pendant, or automatic control (automatic teaching). Here, the robot control device 100 is mainly shown to have a position calculation function for calculating the edge position of the stage S taking into account the inclination of the optical sensors 21 and 22 that detect the edge of the stage S, but it also has other configurations and functions.

[0052] The robot control means 110 operates the transport robot 10. For example, the transport robot 10 holds a sensor device 20 in its hand 11, and the robot control means 110 operates each axis of the transport robot 10, as well as the arm and hand 11, so that two optical sensors 21 and 22 attached to the sensor device 20 pass above the edge of the stage S and the optical sensors 21, 21A, 21B, 22, 22A, and 22B pass above the plane of the stage S.

[0053] The first detection means 120 operates the transport robot 10 using the robot control means 110, and detects the edge of the stage S using the sensor device 20 (two optical sensors 21 and 22) held by the hand 11 of the transport robot 10. For example, the two optical sensors 21 and 22 provided on the back surface of the sensor device 20 emit light downward. When the emitted light reaches a part of the edge of the stage S, the reflected light received by the two optical sensors 21 and 22 changes. The first detection means 120 obtains information from the sensor device 20 that a part of the edge of the stage S has been detected by the two optical sensors 21 and 22.

[0054] The second detection means 130 operates the transport robot 10 using the robot control means 110, and thereby detects the plane of the stage S using the sensor device 20 (optical sensors 21, 21A, 21B and optical sensors 22, 22A, 22B) held by the hand 11 of the transport robot 10. For example, the optical sensors 21, 21A, 21B and optical sensors 22, 22A, 22B provided on the back surface of the sensor device 20 emit light downward. The emitted light then reaches the plane portion of the stage S and the reflected light is received. The second detection means 130 acquires information about the reflected light received in response to the light emitted from the optical sensors 21, 21A, 21B and optical sensors 22, 22A, 22B from the sensor device 20.

[0055] The target position calculation means 140 calculates the edge position of the stage S detected by the optical sensor 21 based on the distances to the plane of the stage S detected by each of the optical sensors 21, 21A, and 21B. Similarly, the target position calculation means 140 calculates the edge position of the stage S detected by the optical sensor 22 based on the distances to the plane of the stage S detected by each of the optical sensors 22, 22A, and 22B.

[0056] The target position calculation means 140 includes a detection position calculation means 141 , a tilt calculation means 142 , and a correction means 143 .

[0057] The detection position calculation means 141 calculates the position of the edge of the stage S detected by the two optical sensors 21 and 22. For example, the detection position calculation means 141 calculates the detected edge position of the stage S (robot coordinate system) based on the position and posture of the transport robot 10 when the edge position of the stage S is detected by the two optical sensors 21 and 22.

[0058] The tilt calculation means 142 calculates the tilt of the optical sensor 21 that detected the edge of the stage S with respect to the plane of the stage S, based on the distances to the plane of the stage S detected by the three optical sensors 21, 21A, and 21B, respectively, and the distances between the three optical sensors 21, 21A, and 21B in the sensor device 20. Specifically, if the area of ​​the optical sensor 21 provided in the sensor device 20 is tilted, the distances from each of the three optical sensors 21, 21A, and 21B to the plane of the stage S will be different, and the tilt calculation means 142 will calculate the tilt of the optical sensor 21 based on the difference in distance.

[0059] Similarly, the tilt calculation means 142 calculates the tilt of the optical sensor 22 that detected the edge of the stage S with respect to the plane of the stage S, based on the distances to the plane of the stage S detected by the three optical sensors 22, 22A, and 22B, respectively, and the distances between the three optical sensors 22, 22A, and 22B in the sensor device 20. Specifically, if the area of ​​the optical sensor 22 provided in the sensor device 20 is tilted, the distances from each of the three optical sensors 22, 22A, and 22B to the plane of the stage S will be different, and the tilt calculation means 142 will calculate the tilt of the optical sensor 22 based on the difference in distance.

[0060] The correction means 143 corrects the edge position of the stage S calculated by the detection position calculation means 141 based on the inclination of the two optical sensors 21 and 22 calculated by the inclination calculation means 142. For example, the two optical sensors 21 and 22 emit light downward, and therefore ideally detect the edge of the stage S in the vertical direction, but if the two optical sensors 21 and 22 are inclined, they actually detect the edge of the stage S at a position deviated from the vertical direction. In other words, the correction means 143 corrects the edge position of the stage S calculated by the detection position calculation means 141, taking into account the inclination of the two optical sensors 21 and 22 calculated by the inclination calculation means 142.

[0061] In this way, while the robot control device 100 moves the hand 11 holding the sensor device 20, the first detection means 120 detects the edge of the stage S, and the second detection means 130 detects the plane of the stage S. Then, the target position calculation means 140 calculates the edge position of the stage S with high accuracy, taking into account the inclination of the optical sensors 21 and 22 that detected the edge of the stage S.

[0062] The calculation of the edge position of the stage S in consideration of the inclination of the two optical sensors 21 and 22 that detect the edge of the stage S will be described in more detail below.

[0063] [Edge position of stage S taking into account the tilt of the optical sensor] 5 is a diagram showing a state in which the sensor device 20 is held by the hand 11 of the transport robot 10 and moves toward the stage S. As shown in Fig. 5, the hand 11 holds the sensor device 20, which has two optical sensors 21 and 22 (a first object sensor and a second object sensor), and has three optical sensors 21, 21A, and 21B (a first sensor group) and three optical sensors 22, 22A, and 22B (a second sensor group).

[0064] As the hand 11 approaches the stage S, the sensor device 20 held by the hand 11 moves above the stage S. Two optical sensors 21 and 22 provided on the sensor device 20 detect the edge of the stage S, and the optical sensors 21, 21A, 21B, 22, 22A, and 22B detect the plane of the stage S.

[0065] 6 is a diagram showing how the edge E of the stage S is detected by the optical sensor provided in the sensor device 20. As shown in FIG. 6, the sensor device 20 held by the hand 11 passes above the edge E of the stage S, causing the optical sensor 21 (22) to detect the edge E of the stage S.

[0066] 5, when the hand 11 is moved in a movement direction approaching the stage S, the sensor device 20 held by the hand 11 passes above the edge E of the stage S. At that time, the optical sensor 21 (22) detects the edge E of the stage S by receiving reflected light of light emitted downward from the optical sensor 21 (22), and the detected position calculation means 141 calculates the position (robot coordinate system) of the edge E of the stage S based on the position and posture of the transport robot 10 at the time of detection.

[0067] 7 is a diagram showing how the distance to the plane F of the stage S is detected by two optical sensors provided in the sensor device 20. As shown in FIG. 7, when the sensor device 20 held by the hand 11 passes above the plane F of the stage S, the optical sensor 21 (22) and the optical sensor 21A (22A) detect the plane F of the stage S.

[0068] 5, when the hand 11 is moved in a movement direction approaching the stage S, the sensor device 20 held by the hand 11 passes above the plane F of the stage S. At that time, the optical sensor 21 (22) and the optical sensor 21A (22A) detect the plane F of the stage S by receiving reflected light of light emitted downward from the optical sensor 21 (22) and the optical sensor 21A (22A), and the tilt calculation means 142 calculates the distance d1 from the optical sensor 21 (22) to the plane F and the distance d2 from the optical sensor 21A (22A) to the plane F, respectively.

[0069] The tilt calculation means 142 can calculate the tilt θ of the optical sensor 21 (22) provided in the sensor device 20 with respect to the plane F of the stage S based on the difference d between the distance d1 and the distance d2 and the distance between the optical sensor 21 (22) and the optical sensor 21A (22A). It is assumed that the distance between the optical sensor 21 (22) and the optical sensor 21A (22A) is known in advance. Here, the optical sensor 21 (22) and the optical sensor 21A (22A) are provided on the same plane (bottom surface) in the sensor device 20, and therefore the inter-sensor distance between the optical sensor 21 (22) and the optical sensor 21A (22A) is known in advance. This makes it possible to easily calculate the tilt θ without the need for processing such as measuring the inter-sensor distance.

[0070] In this way, the correction means 143 corrects the position (robot coordinate system) of the edge E of the stage S calculated by the detection position calculation means 141 based on the tilt θ of the optical sensor 21 (22) calculated by the tilt calculation means 142 and the distance d1, thereby making it possible to grasp with high precision the position of the edge E of the stage S. For example, the correction means 143 may correct the position (robot coordinate system) of the edge E of the stage S based on the tilt θ of the optical sensor 21 (22) and the distance between the optical sensor 21 (22) and the stage S detected by the optical sensor 21 (22) (here, the distance d1 may be sufficient).

[0071] Here, we have explained the inclination of the optical sensor 21 (22) relative to the arrangement direction of the optical sensor 21 (22) and the optical sensor 21A (22A), which is the movement direction of the hand 11. However, the inclination of the optical sensor 21 (22) relative to the arrangement direction of the optical sensor 21 (22) and the optical sensor 21B (22B), which is perpendicular to the movement direction, can also be corrected by taking into account the inclination, and the position (robot coordinate system) of the edge E of the stage S calculated by the detection position calculation means 141 can be corrected.

[0072] [Position calculation method for calculating the edge position of stage S] Next, a method for calculating the edge position of the stage S in consideration of the inclination of the two optical sensors 21 and 22 in the sensor device 20 held by the hand 11 will be specifically described in detail.

[0073] 8 is a flowchart showing the processing flow of a position calculation method M100 for calculating the position of an object, which is executed by a robot controller 100 according to one embodiment of the present invention. As shown in FIG. 8, the position calculation method M100 includes steps S110 to S150, and each step is mainly executed by a processor included in the robot controller 100.

[0074] In step S110, the transport robot 10 (hand 11) holding the sensor device 20 is moved (robot control step). As a specific example, the transport robot 10 holds the sensor device 20 in the hand 11, and the robot control means 110 operates the transport robot 10 (hand 11) so that the two optical sensors 21 and 22 attached to the sensor device 20 pass above the edge E of the stage S, and the optical sensors 21, 21A, 21B, 22, 22A, and 22B pass above the plane F of the stage S.

[0075] In step S120, the edge E of the stage S is detected by the two optical sensors 21 and 22 (first detection step). As a specific example, the sensor device 20 held by the hand 11 passes above the edge E of the stage S, causing the two optical sensors 21 and 22 to detect the edge E of the stage S.

[0076] In step S130, the sensor group (optical sensors 21, 21A, 21B, 22, 22A, and 22B) detects the plane F of the stage S (second detection step). As a specific example, the sensor device 20 held by the hand 11 passes above the plane F of the stage S, causing the optical sensors 21, 21A, 21B, 22, 22A, and 22B to detect the plane F of the stage S.

[0077] In step S140, based on the distances to the plane F of the stage S detected by the sensor group (respective optical sensors 21, 21A, 21B, 22, 22A, 22B) in step S130, the tilt of the optical sensor 21 (22) with respect to the plane F is calculated. As a specific example, the tilt calculation means 142 calculates the tilt of the optical sensor 21 (first object sensor) that detected the edge E of the stage S with respect to the plane F of the stage S, based on the distances to the plane F of the stage S detected by the three optical sensors 21, 21A, 21B (first sensor group), respectively, and the distances between the three optical sensors 21, 21A, 21B in the sensor device 20. Similarly, the inclination calculation means 142 calculates the inclination of the optical sensor 22 (second object sensor) that detected the edge E of the stage S relative to the plane F of the stage S based on the distances to the plane F of the stage S detected by the three optical sensors 22, 22A, 22B (second sensor group) respectively and the distances between the three optical sensors 22, 22A, 22B in the sensor device 20.

[0078] In step S150, the position of the edge E of the stage S detected in step S120 is corrected based on the inclination of the optical sensor 21 (22) calculated in step S140 and the distance between the optical sensor 21 (22) and the stage S detected by the optical sensor 21 (22). As a specific example, the correction means 143 corrects the position of the edge E of the stage S calculated by the detection position calculation means 141, taking into account the inclination θ of the two optical sensors 21 and 22 calculated by the inclination calculation means 142.

[0079] In this way, the robot control device 100 calculates the position of the edge E of the stage S with high precision, taking into account the inclination of the optical sensors 21 and 22 that detected the edge E of the stage S. Then, by calculating the center of the stage S based on the position of the edge E of the stage S, it is possible to transport the object (wafer W) with high precision to the center (target position) of the stage S. Note that if three points on the edge E of the stage S are identified, the center of the stage S can be uniquely calculated by drawing a circle that passes through these three points.

[0080] Furthermore, if the radius (diameter) of the circle that constitutes the stage S is known in advance (as a fixed value), two points on the edge E of the stage S can be identified, and two different circles can be drawn from those two points. Then, one of the two different circles can be selected based on the positional relationship between the stage S and the two optical sensors 21 and 22 provided in the sensor device 20 (the moving direction of the hand 11). In other words, if two points on the edge E of the stage S are identified, the center position of the stage S can be calculated.

[0081] When two or three points on the edge E of the stage S are detected to calculate the center of the stage S, it is preferable that these detection points are as far apart as possible, as this reduces errors in the circle of the stage S that is drawn based on these detection points. For example, when two optical sensors 21 and 22 are provided in the sensor device 20, it is preferable to provide them as far apart as possible on both sides. As a result, the center of the stage S can be calculated with high accuracy.

[0082] Furthermore, when detecting two or three points on the edge E of the stage S, the hand 11 may be moved in one direction to detect multiple different points (two or three points) on the edge E of the stage S, or after detecting the edge E of the stage S, the hand 11 may retreat once and then approach the stage S at a different angle to detect multiple different points (two or three points) on the edge E of the stage S.

[0083] Here, the edge E of the stage S is detected (step S120) and then the plane F of the stage S is detected (step S130), but the order can be reversed; specifically, the plane F of the stage S can be detected first, and then the edge E of the stage S can be detected.

[0084] As described above, according to the robot control device 100, position calculation method M100, and sensor device 20 according to an embodiment of the present invention, the sensor device 20 is held by the hand 11 of the transport robot 10, and the robot control means 110 operates the transport robot 10 so that the two optical sensors 21 and 22 attached to the sensor device 20 pass above the edge E of the stage S and the optical sensors 21, 21A, 21B, 22, 22A, and 22B pass above the plane F of the stage S. The first detection means 120 detects the edge E of the stage S with the two optical sensors 21 and 22, and the second detection means 130 detects the plane F of the stage S with the optical sensors 21, 21A, 21B, 22, 22A, and 22B. Then, the target position calculation means 140 calculates the position of the edge E of the stage S detected by the optical sensor 21 based on the distances to the plane F of the stage S detected by each of the optical sensors 21, 21A, and 21B, taking into account the inclination of the optical sensor 21. Similarly, the target position calculation means 140 calculates the position of the edge E of the stage S detected by the optical sensor 22 based on the distances to the plane F of the stage S detected by each of the optical sensors 22, 22A, and 22B, taking into account the inclination of the optical sensor 22. As a result, if the center of the stage S is calculated based on the position of the edge E of the stage S, it is possible to transport the object (wafer W) to the center (target position) of the stage S with high accuracy.

[0085] In this embodiment, the optical sensors 21 and 22 are provided at the rear of the sensor device 20 with respect to the moving direction of the hand 11, but this is not limitative and the optical sensors 21 and 22 may be provided in accordance with the shape and moving direction of the hand 11, and further with the configuration of the stage S and its surroundings. For example, if the space on the other side of the stage S with respect to the moving direction of the hand 11 is limited, the optical sensors 21 and 22 may be provided in front of the moving direction of the hand 11.

[0086] In addition, in this embodiment, the sensor device 20 is provided with two optical sensors 21 and 22 as optical sensors for detecting the edge E of the stage S, but this is not limited to this, and for example, the optical sensor may be one or three or more, and it is preferable to provide the required number of optical sensors depending on the detection of the edge E of the stage S.

[0087] Furthermore, in this embodiment, in order to grasp the inclination of the optical sensors 21 and 22, the first sensor group is configured with three optical sensors 21, 21A, and 21B (the optical sensor 21 also serves as a target sensor), and the second sensor group is configured with three optical sensors 22, 22A, and 22B (the optical sensor 22 also serves as a target sensor), but this is not limitative. For example, the second sensor group may be configured with four optical sensors.

[0088] Fig. 9 is a diagram showing another configuration of sensor device 20. As shown in Fig. 9, sensor device 20 has four optical sensors 21, 22, 23, and 24 as object sensors for detecting an object, optical sensors 21A to 21D near optical sensor 21, optical sensors 22A to 22D near optical sensor 22, optical sensors 23A to 23D near optical sensor 23, and optical sensors 24A to 24D near optical sensor 24.

[0089] Here, one of the optical sensors constituting the first sensor group (optical sensors 21A to 21D) is not also used as the target sensor by optical sensor 21, and for example, the arrangement direction of optical sensors 21A and 21C is perpendicular to the arrangement direction of optical sensors 21B and 21D, making it possible to grasp the tilt in each direction of optical sensor 21. The same is true for the second sensor group (optical sensors 22A to 22D), the third sensor group (optical sensors 23A to 23D), and the fourth sensor group (optical sensors 24A to 24D).

[0090] When optical sensors (target sensors) are provided in the sensor device 20, the inclination of the installation surface is not uniform depending on the region (position) where the sensors are provided, and for example, the inclination may differ between the center, the outer periphery, the left and right, or the top and bottom of the sensor device 20. In such cases, it is preferable to calculate the inclination of each optical sensor (target sensor) by providing a sensor group made up of multiple optical sensors near each optical sensor so as to correspond to the optical sensor (target sensor).

[0091] In this way, an optical sensor (sensor for object) and a plurality of optical sensors (sensor group) for grasping the tilt of the optical sensor (sensor for object) typically correspond one-to-one, but this is not limiting, and for example, a configuration in which a plurality of optical sensors (sensor group) are provided for a plurality of optical sensors (sensor for object) may be adopted. Specifically, a plurality of optical sensors (sensor group) for grasping the tilt of adjacent optical sensors (sensors for object) may be shared.

[0092] Furthermore, the optical sensor (target sensor) and a plurality of optical sensors (sensor group) for determining the inclination of the optical sensor (target sensor) are typically arranged on the same plane of the sensor device 20, but are not limited to this. For example, the target sensor and the sensor group attached to the sensor device 20 may be arranged on different planes as long as they have the same inclination or the difference in inclination is known.

[0093] Furthermore, in this embodiment, the sensor device 20 is circular, but is not limited to this and may be rectangular, triangular, or any other polygonal shape. Specifically, it is sufficient that the sensor device is positioned in accordance with the shape of a robot hand so that the optical sensor provided in the sensor device is not blocked by the robot hand when the sensor device is held by the robot hand.

[0094] Furthermore, the sensor device 20 is not limited to being placed and held by a robot hand from below, but may be held by being sandwiched between robot hands from both sides, for example.

[0095] Furthermore, instead of a configuration in which the sensor device is held by the robot hand, for example, a configuration in which the sensor is attached to the robot hand (part of the robot) as long as it is capable of detecting the edge E of the stage S. A configuration in which the sensor device or the sensor provided with the sensor is installed on the robot hand (part of the robot) using, for example, a magnet or a suction cup that can be easily attached and detached to the robot hand (part of the robot) may also be used.

[0096] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The elements of the embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those illustrated and can be modified as appropriate. Furthermore, configurations shown in different embodiments can be partially substituted or combined with each other. [Explanation of symbols]

[0097] 1...Transport robot system, 10...Transport robot, 11...Hand, 20...Sensor device, 21, 21A to 21D, 22, 22A to 22D, 23, 23A to 23D, 24, 24A to 24D...Optical sensors, 100...Robot control device, 110...Robot control means, 120...First detection means, 130...Second detection means, 140...Object position calculation means, 141...Detected position calculation means, 142...Calculation means, 143...Correction means, S, S1 to S3...Stage, W...Wafer, WS...Work space, E...Edge, F...Plane, d...Difference, d1, d2...Distance, M100...Position calculation method, S110 to S150...Each step of position calculation method M100

Claims

1. A robot control device for controlling an operation of a robot, A robot control means for operating the robot; a first detection means for detecting an object by an object sensor held by the robot by operating the robot using the robot control means; a second detection means for detecting a plane including the target by a sensor group including a plurality of sensors held by the robot by operating the robot using the robot control means; and an object position calculation means for calculating a position of the object detected by the object sensor based on each distance to the plane detected by each of the plurality of sensors in the sensor group and position information of the object sensor and the sensor group. Robot control device.

2. The target position calculation means a detection position calculation means for calculating a detection position of an object detected by the object sensor; a tilt calculation means for calculating a tilt of the target sensor with respect to the plane based on each distance to the plane detected by each of the plurality of sensors in the sensor group and each distance between the plurality of sensors in the sensor group; and a correction means for correcting the detection position of the object based on the inclination of the object sensor. The robot control device according to claim 1 .

3. The object sensor and the plurality of sensors in the sensor group are arranged on the same plane. The robot control device according to claim 1 .

4. the sensor group includes two sensor groups each including a pair of a first sensor and a second sensor corresponding to the first sensor; The robot control device according to claim 1 .

5. The two pairs of sensor groups are arranged orthogonal to each other. The robot control device according to claim 4.

6. The subject sensor functions as one sensor among a plurality of sensors in the sensor group. The robot control device according to claim 1 .

7. The object sensor is provided as at least a first object sensor and a second object sensor, The sensor group is provided as at least a first sensor group and a second sensor group so as to correspond to the first object sensor and the second object sensor, respectively. The robot control device according to claim 1 .

8. a distance between each of the plurality of sensors in the first sensor group and the first object sensor is smaller than a distance between any of the plurality of sensors in the second sensor group and the second object sensor that is closest to the plurality of sensors in the first sensor group and the first object sensor; The robot control device according to claim 7.

9. The target sensor and the plurality of sensors in the sensor group are provided on a sensor device held by the robot. The robot control device according to any one of claims 1 to 8.

10. A position calculation method for calculating a position of an object executed by a robot control device that controls an operation of a robot, comprising: a robot control step of operating the robot; a first detection step of detecting an object by an object sensor held by the robot by operating the robot in the robot control step; a second detection step of detecting a plane including the target by a sensor group including a plurality of sensors held by the robot by operating the robot in the robot control step; and an object position calculation step of calculating a position of the object detected by the object sensor based on each distance to the plane detected by each of the plurality of sensors in the sensor group and position information of the object sensor and the sensor group. Location calculation method.

11. A sensor device used in a position calculation method for calculating a position of an object, the method being executed by a robot control device that controls the operation of a robot, comprising: An object sensor that detects the object; A sensor group including a plurality of sensors that detect a plane including the object; The position calculation method includes: a robot control step of operating the robot; a first detection step of detecting an object by an object sensor of the sensor device held by the robot by operating the robot in the robot control step; a second detection step of detecting a plane including the target by a sensor group including a plurality of sensors of the sensor device held by the robot by operating the robot in the robot control step; and an object position calculation step of calculating a position of the object detected by the object sensor based on each distance to the plane detected by each of the plurality of sensors in the sensor group and position information of the object sensor and the sensor group. Sensor device.

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