Robot control device, calibration method, and sensor device used therein

Abstract

To provide a robot control device capable of appropriately calculating a positional relationship between a robot and a sensor, a calibration method, and a sensor device used therein.SOLUTION: A robot control device 100 includes: robot control means 110 that operates a robot 10 in which an arc shape with a predetermined reference point T in the robot 10 as a center is formed in a part of the robot 10; detection means 120 that detects multiple times a part of the arc shape by sensors 21, 22 provided in a sensor device 20, by operation of the robot 10; reference point position acquisition means 130 that acquires a plurality of positions T1 to T3 of the reference point T of when detection is made by the detection means 120; and sensor position calculation means 140 that calculates positions of the sensors 21, 22 on the basis of the plurality of positions T1 to T3.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] 2. Description of the Related Art In recent years, many robots have come into widespread use in the industrial world. The robots are used, for example, in the assembly, welding, and transportation of electronic and mechanical parts, and are contributing to the efficiency and automation of factory production lines.

[0003] Transport robots used in semiconductor manufacturing equipment to transport wafers require teaching to transport the wafer 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 this teaching process.

[0004] For example, a technique is known in which a camera or a sensor is attached to a transport robot to grasp the positional relationship between the transport robot and a target position, as well as the surrounding environment such as obstacles, and transport an object appropriately to the target position.

[0005] In Patent Document 1, a substrate-type jig provided 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.Then, a technology is disclosed in which the relative position of the hand to the substrate holding part in a plan view is calculated based on the relative positions to the rotation loci obtained from the three optical sensors. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2022-148237 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in Patent Document 1, the relative position between the hand and the substrate holding part is calculated based on the relative positions obtained by three optical sensors provided on the substrate-type jig held by the hand, but nothing is disclosed about the positional relationship between the hand and the three optical sensors.

[0008] When the three optical sensors are mounted on the substrate-type jig, there may be misalignment or individual variation, and when the substrate-type jig is held by the hand, there may also be misalignment. In other words, the positional relationship between the hand and the three optical sensors may be misaligned, resulting in a problem that the position of the hand (robot) relative to the substrate holder (for example, the target position for placing the substrate) cannot be calculated appropriately.

[0009] Therefore, an object of the present invention is to provide a robot control device, a calibration method, and a sensor device used therein that are capable of appropriately calculating the positional relationship between a robot and a sensor. [Means for solving the problem]

[0010] A robot control device according to one aspect 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, part of which forms an arc shape centered on a predetermined reference point on the robot, a detection means for detecting part of the arc shape multiple times with a sensor provided in a sensor device by operating the robot using the robot control means, a reference point position acquisition means for acquiring multiple positions of the reference point when detected by the detection means, and a sensor position calculation means for calculating the position of the sensor based on the multiple positions.

[0011] According to this aspect, the robot control means operates the robot, a part of which forms an arc shape with a predetermined reference point on the robot as a center. The detection means detects the part of the arc shape on the robot multiple times using a sensor provided in the sensor device, the reference point position acquisition means acquires the position of the predetermined reference point at that time, and the sensor position calculation means calculates the position of the sensor based on the multiple positions of the reference point. This makes it possible to appropriately calculate the positional relationship between the robot and the sensor in the sensor device.

[0012] In the above aspect, the sensor position calculation means may calculate the position of the sensor based on at least two positions of the reference point when detected by the sensor and a diameter of a circle configured to include a part of the arc shape.

[0013] According to this aspect, as long as the diameter (radius) of the circle that is constructed on the robot so as to include a circular arc shape in part is known in advance (as a fixed value), the sensor position calculation means requires at least two reference points when detected by the sensor, and can efficiently and appropriately calculate the positional relationship between the robot and the sensor.

[0014] In the above aspect, the sensor position calculation means may calculate the position of the sensor based on at least three positions of the reference point when detected by the sensor.

[0015] According to this aspect, as long as there are at least three reference points detected by the sensor, the positional relationship between the robot and the sensor can be appropriately calculated regardless of the diameter (radius) of the circle configured on the robot to include a circular arc shape as part of it (e.g., even if there are individual differences in the robot or measurement errors).

[0016] In the above aspect, the robot control means may operate the robot to hold the sensor device based on the position of the reference point and the position of the sensor calculated by the sensor position calculation means, and grasp the relative position between the position of the reference point and the position of the sensor.

[0017] According to this aspect, the robot control means can grasp the relative position between the position of the reference point and the position of the sensor based on the position of the reference point and the position of the sensor calculated by the sensor position calculation means, while holding the sensor device so as to avoid the area in which the sensor is attached.

[0018] A calibration method according to one aspect of the present invention is a calibration method executed by a robot control device that controls the operation of a robot, and includes a robot control step of operating the robot, a part of which forms an arc shape centered on a predetermined reference point on the robot, a detection step of detecting a part of the arc shape multiple times with a sensor provided in a sensor device by operating the robot in the robot control step, a reference point position acquisition step of acquiring multiple positions of the reference point when detected in the detection step, and a sensor position calculation step of calculating the position of the sensor based on the multiple positions.

[0019] According to this aspect, the robot control step operates the robot, which is configured to have a part of an arc shape centered on a predetermined reference point on the robot. The detection step detects a part of the arc shape on the robot multiple times using a sensor provided in the sensor device, the reference point position acquisition step acquires the position of the predetermined reference point at that time, and the sensor position calculation step calculates the position of the sensor based on the multiple positions of the reference point. This makes it possible to appropriately calculate the positional relationship between the robot and the sensor in the sensor device.

[0020] A sensor device according to one aspect of the present invention is a sensor device used in a calibration method executed by a robot control device that controls the operation of a robot, and the calibration method includes a robot control step of operating the robot, which forms a part of an arc shape centered on a predetermined reference point on the robot, a detection step of detecting a part of the arc shape multiple times with a sensor provided in the sensor device by operating the robot in the robot control step, a reference point position acquisition step of acquiring multiple positions of the reference point when detected in the detection step, and a sensor position calculation step of calculating the position of the sensor based on the multiple positions.

[0021] According to this aspect, the robot control step operates the robot, which is configured to have a part of an arc shape centered on a predetermined reference point on the robot. The detection step detects a part of the arc shape on the robot multiple times using a sensor provided in the sensor device, the reference point position acquisition step acquires the position of the predetermined reference point at that time, and the sensor position calculation step calculates the position of the sensor based on the multiple positions of the reference point. This makes it possible to appropriately calculate the positional relationship between the robot and the sensor in the sensor device. Effect of the Invention

[0022] According to the present invention, it is possible to provide a robot control device, a calibration method, and a sensor device used therein, which are capable of appropriately calculating the positional relationship between a robot and a sensor. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic diagram showing a system configuration of a transfer robot system 1 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing how the transfer robot 10 operates in a clean environment. [Diagram 3] 1 is a diagram showing a state in which a sensor device 20 is held by a hand 11 of 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. [Diagram 5] 1 is a diagram for explaining the positional relationship between a fixed sensor 80 and a circular moving body 99. FIG. [Figure 6] FIG. 1 is a diagram showing an example of a hand 11 that forms a part of a circle (arc shape). [Figure 7] 1 is a diagram showing how the tip of the hand 11 is detected by the optical sensor 21 and the position of the optical sensor 21 in the sensor device 20 is grasped. [Figure 8] 1 is a diagram showing a state in which a sensor device 20 is held by a hand 11 of a transfer robot 10. FIG. [Figure 9] 1 is a flowchart showing the flow of processing of a calibration method M100 executed by a robot control device 100 according to an embodiment of the present invention. [Figure 10] 1 is a diagram showing an example of a hand 11 in which parts of a circle (arc shapes) are formed on both sides of the hand 11. FIG. [Figure 11] 1 is a diagram showing an example of a hand 11 in which a part of a circle (arc shape) is formed inside the hand 11. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an embodiment of the present invention will be specifically described 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 interpretation of the present invention. In addition, in order to facilitate understanding of the description, the same reference numerals are used as far as possible for the same components in each drawing, and duplicated descriptions may be omitted.

[0025] <One embodiment> [Transport robot system configuration] 1 is a schematic diagram showing a 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.

[0026] The transport robot 10 is, for example, a horizontal articulated robot intended for transporting wafers, and is a clean transport robot used for transport in clean environments in the manufacture of semiconductor devices and flat panel displays, the medical and food industries, etc. In this embodiment, the transport 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 a wafer (object) is held and transported by the hand 11, as an example.

[0027] 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 inputted in the operating device. Based on the operation instruction information, the robot control device 100 operates each axis of the transport robot 10 as well as the arms and hands 11 in order to start and stop the transport robot 10, and to pick up, transport and set down an object.

[0028] An operating device such as a teach pendant accepts 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 inputs appropriate instruction information using an operating device such as a teach pendant, for example, for starting and stopping the transport robot 10, further, settings for the transport robot 10, operations of the arms and hands 11, registration of teaching points, and the like.

[0029] Furthermore, regarding the registration of teaching points, teaching points on the operation path may be automatically registered by automatic teaching, instead of the operator sequentially registering the teaching points on the operation path using an operating device such as a teach pendant while operating the transport robot 10. Such automatic teaching is effective, for example, in an environment or situation where the intrusion space (work space) of the operator cannot be sufficiently secured.

[0030] [Wafer transportation] Fig. 2 is a schematic diagram showing the operation of the transfer robot 10 in a clean environment. As shown in Fig. 2, the transfer robot 10 installed in the work space WS transfers the wafer W held by the hand 11 to each of the stages S1 to S3 in a process chamber in a vacuum environment.

[0031] Specifically, the transfer robot 10 operates the arms and hands 11 based on operation instruction information from the robot control device 100 to take out the wafer W and transfer it to a destination stage.

[0032] Here, the target position to which the wafer W is transferred and set is, for example, the center of each stage, and it is preferable to set the wafer W at the center of each stage with high accuracy, and it is important for the robot control device 100 to properly grasp the center (target position) of each stage. Then, the robot control device 100 operates the transfer robot 10 so that the TCP (Tool Center Point) of the hand 11 in the transfer robot 10 coincides with the target position, and the operation is preferably registered as teaching data.

[0033] [Sensor device configuration] 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 a state in which the sensor device 20 is held by the hand 11 of the transport robot 10. As shown in Fig. 3, the hand 11 holds the sensor device 20 having two optical sensors 21 and 22.

[0034] The two optical sensors 21 and 22 are attached to the rear surface of the sensor device 20, and are reflective optical sensors capable of calculating distance by receiving reflected light of light emitted downward from a light source.

[0035] Since the sensor device 20 is placed on the hand 11, the two optical sensors 21 and 22 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 two optical sensors 21 and 22 are attached.

[0036] The sensor device 20 may also be equipped with a control unit and a communication unit, and the two optical sensors 21 and 22 control the light emitted from the light source, receive reflected light, and notify information thereabout, for example, to the robot control device 100.

[0037] In this way, when teaching the robot, the sensor device 20 is held by the hand 11 of the transport robot 10, and highly accurate teaching data is generated while properly grasping the positional relationship between the transport robot 10 and the target position, as well as the surrounding environment such as obstacles.

[0038] Regarding the sensor device 20 (two optical sensors 21 and 22) used in teaching the robot, calibration of the two optical sensors 21 and 22 when held by the hand 11 of the transfer robot 10 will be described.

[0039] [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 detection unit 120, a reference point position acquisition unit 130, and a sensor position calculation unit 140, and controls the operation of the transport robot 10. The transport robot 10 operated by the robot control device 100 is detected by a sensor device 20 (two optical sensors 21 and 22) that is fixedly disposed, and the robot control device 100 grasps the positional relationship between the transport robot 10 and the two optical sensors 21 and 22 based on the detection result.

[0040] 1, the robot control device 100 is connected to the transport robot 10, and further has many functions for carrying out 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 with respect to a calibration function for teaching the robot, but it also has other configurations and functions.

[0041] The robot control means 110 operates the transport robot 10, which forms a part of an arc shape centered on a predetermined reference point on the transport robot 10. Here, the predetermined reference point on the transport robot 10 may be, for example, the TCP (Tool Center Point) of the hand 11, and the tip of the hand 11 forms a part of a circle (arc shape) drawn with the TCP as the center. The robot control means 110 operates the transport robot 10 so that the hand 11 forming the arc shape is detected by two optical sensors 21 and 22 of the sensor device 20, which is fixedly arranged.

[0042] The detection means 120 operates the transport robot 10 using the robot control means 110, and detects a part of the arc shape multiple times using the two optical sensors 21 and 22 provided in the sensor device 20. For example, the two optical sensors 21 and 22 provided on the back surface of the sensor device 20 emit light downward, and when a part of the tip (arc shape) of the hand 11 of the transport robot 10 reaches the position of the emitted light, the reflected light received by the two optical sensors 21 and 22 changes. The detection means 120 acquires information from the sensor device 20 that a part of the tip (arc shape) of the hand 11 has been detected by the two optical sensors 21 and 22.

[0043] It should be noted that the tip (arc shape) of the hand 11 is detected multiple times by the two optical sensors 21 and 22, and a different position of the tip (arc shape) of the hand 11 is detected each time by each of the two optical sensors 21 and 22.

[0044] The reference point position acquisition means 130 acquires a plurality of positions of the reference point when detected by the detection means 120. For example, the reference point position acquisition means 130 acquires the TCP of the hand 11 when a part of the tip portion (arc shape) of the hand 11 is detected by the two optical sensors 21 and 22. Specifically, the robot control device 100 acquires the TCP (robot coordinate system) of the hand 11 in the transport robot 10 based on the position and posture of the transport robot 10 when a part of the tip portion (arc shape) of the hand 11 is detected by the two optical sensors 21 and 22.

[0045] The sensor position calculation means 140 calculates the positions (robot coordinate system) of the two optical sensors 21 and 22 based on the multiple TCPs (robot coordinate systems) of the hand 11 acquired by the reference point position acquisition means 130. Specifically, as described above, the tip (arc shape) of the hand 11 calculates the center of a circle based on the multiple TCPs as the positions of the two optical sensors 21 and 22.

[0046] In this way, the robot control device 100 can grasp the positional relationship between the transport robot 10 (TCP of the hand 11) and the two optical sensors 21 and 22 attached to the sensor device 20 held by the hand 11 of the transport robot 10.

[0047] Then, based on the reference point TCP and the positions of the two optical sensors 21 and 22 calculated by the sensor position calculation means 140, the robot control means 110 operates the transport robot 10 to avoid the area where the two optical sensors 21 and 22 are attached so that the light emitted downward from the two optical sensors 21 and 22 is not blocked by the hand 11, and holds the sensor device 20.

[0048] The robot control device 100 can hold the sensor device 20 using the hand 11 of the transport robot 10 and properly grasp the relative position (positional relationship) between the TCP of the hand 11 and the two optical sensors 21 and 22, and can therefore perform highly accurate robot teaching using the two optical sensors 21 and 22.

[0049] The calibration of the two optical sensors 21 and 22 will now be described in more detail.

[0050] [Principle of positioning using reflective sensors] First, the positional relationship between the fixed sensor and the circular moving body will be described. Fig. 5 is a diagram for explaining the positional relationship between the fixed sensor 80 and the circular moving body 99. As shown in Fig. 5, a circular moving body 99 (corresponding to the hand 11) with a center 90 (corresponding to the TCP) moves toward the fixed sensor 80 (corresponding to the optical sensor 21 or 22).

[0051] Then, when the moving body 99 approaches the sensor 80 and a part of the arc of the moving body 99 is detected by the sensor 80, this is recorded as the center position 91 of the moving body 99 (first time). Next, when the moving body 99 approaches the sensor 80 from a position different from the first time, and a part of the arc of the moving body 99 (a place different from the first time) is detected by the sensor 80, this is recorded as the center position 92 of the moving body 99 (second time). Furthermore, when the moving body 99 approaches the sensor 80 from a position different from the first and second times, and a part of the arc of the moving body 99 (a place different from the first and second times) is detected by the sensor 80, this is recorded as the center position 93 of the moving body 99 (third time).

[0052] In this way, when the center positions 91, 92, and 93 are obtained, it is possible to uniquely draw a circle 80C that includes these three points. Then, the center position of the circle 80C can be calculated as the position of the sensor 80.

[0053] [Shape of the transport robot (hand)] In order to utilize the principle regarding the positional relationship between the sensor and the moving body described with reference to FIG. 5, the hand 11 of the transfer robot 10 forms a part of a circle (arc shape).

[0054] Fig. 6 is a diagram showing an example of the hand 11 constituting a part of a circle (arc shape). As shown in Fig. 6, the tips 11A and 11B of the hand 11 constitute a part (arc shape) of a circle C having a radius r and centered at the TCP (T).

[0055] The hand 11 of the transport robot 10 is moved toward the fixedly disposed sensor device 20. When the hand 11 approaches the sensor device 20, the tips 11A and 11B of the hand 11 are detected by the two optical sensors 21 and 22 of the sensor device 20, and the positions of the two optical sensors 21 and 22 can be calculated based on the principle described with reference to FIG.

[0056] [Optical sensor position (robot coordinate system)] 7 is a diagram showing how the tip of the hand 11 is detected by the optical sensor 21 to grasp the position of the optical sensor 21 in the sensor device 20. First, the sensor device 20 to which the two optical sensors 21 and 22 are attached is fixed and arranged, for example, by placing it on a support pin or the like. The two optical sensors 21 and 22 are reflective optical sensors that emit light downward, and are attached to the back surface of the sensor device 20.

[0057] In state (A), the hand 11 of the transport robot 10 is moved toward the sensor device 20, which is fixedly arranged. The hand 11 approaches the sensor device 20 and enters below the sensor device 20, and the arc-shaped portion of the tip of the hand 11 is detected by the optical sensor 21, and the TCP (T1) at that time is recorded (first time).

[0058] Thereafter, the hand 11 is moved in a direction away from the sensor device 20, and in state (B), the hand 11 is moved toward the sensor device 20 from a position different from that in the first time. The hand 11 approaches the sensor device 20 and enters below the sensor device 20, and the arc-shaped portion of the tip of the hand 11 is detected by the optical sensor 21, and the TCP (T2) at that time is recorded (second time).

[0059] Thereafter, the hand 11 is moved in a direction away from the sensor device 20, and in state (C), the hand 11 is moved toward the sensor device 20 from a position different from the first and second times. The hand 11 approaches the sensor device 20 and enters below the sensor device 20, and the arc-shaped portion of the tip of the hand 11 is detected by the optical sensor 21, and the TCP (T3) at that time is recorded (third time).

[0060] In this way, when the three TCPs (T1 to T3) are obtained, a circle 21C including these three points can be uniquely drawn. Then, the center position of the circle 21C can be calculated as the position of the optical sensor 21 (robot coordinate system).

[0061] Similarly, the position of the optical sensor 22 (robot coordinate system) can also be calculated.

[0062] Fig. 8 is a diagram showing a state in which the sensor device 20 is held by the hand 11 of the transfer robot 10. As shown in Fig. 8, the hand 11 holds the sensor device 20 so as to avoid the area where the two optical sensors 21 and 22 are attached.

[0063] As explained using Figure 7, the robot control device 100 is aware of the positions of the TCP and the two optical sensors 21 and 22, so it can operate the transport robot 10 (hand 11) to avoid the area where the two optical sensors 21 and 22 are attached, and can scoop up the sensor device 20 placed on a support pin or the like from below and place it on the hand 11.

[0064] The robot control device 100 then performs robot teaching in a state in which the sensor device 20 is held by the hand 11 of the transport robot 10. If the stage to which the robot is to be transported is circular, the center position of the stage may be obtained using the sensor device 20 having the two optical sensors 21 and 22 whose positions have been calibrated as described above.

[0065] Specifically, the robot control device 100 brings the hand 11 holding the sensor device 20 close to the stage, and detects the edge portion (circular shape) of the stage with the optical sensor 21 and / or the optical sensor 22.

[0066] When the stage is circular, the center position of the stage can be calculated by detecting three points on the edge portion (circular shape) of the stage by the optical sensor 21 and / or the optical sensor 22.

[0067] Generally, the circular shape of the stage is formed as a highly accurate circle, and by calculating the center position of the stage using the above method, the center position of the stage can be grasped with high accuracy. As a result, for example, when the transfer robot 10 transfers the wafer W to the center position (target position) of the stage, the robot can be taught to transfer with higher accuracy.

[0068] Furthermore, if the radius or diameter of the circular stage is known in advance, two points on the edge portion (circular shape) of the stage can be detected by optical sensor 21 and / or optical sensor 22, and the center position of the stage can be determined based on the positional relationship between optical sensor 21 and / or optical sensor 22 and the stage.

[0069] [Calibration method] Next, a method for calibrating the two optical sensors 21 and 22 in the sensor device 20 held by the hand 11 will be specifically described in detail.

[0070] 9 is a flowchart showing the process flow of a calibration method M100 executed by a robot controller 100 according to one embodiment of the present invention. As shown in FIG 9, the calibration method M100 includes steps S110 to S160, and each step is mainly executed by a processor included in the robot controller 100.

[0071] In step S110, the sensor device 20 is installed. As a specific example, the sensor device 20 equipped with the two optical sensors 21 and 22 is placed on a support pin or the like and fixed in place.

[0072] In step S120, the transport robot 10 (hand 11) is moved (robot control step). As a specific example, the robot control means 110 operates the transport robot 10 (hand 11) so that the tip of the hand 11 in the transport robot 10 is detected by the two optical sensors 21 and 22. Note that the tip of the hand 11 forms, for example, an arc shape (11A and 11B) centered on the TCP (T) as shown in FIG. 6.

[0073] In step S130, a part (arc) of the hand 11 is detected by the optical sensors 21 and 22 (detection step). As a specific example, the detection means 120 operates the transfer robot 10 (hand 11) in step S120, thereby detecting parts of the tips 11A and 11B (arc shapes) of the hand 11 by the two optical sensors 21 and 22.

[0074] In step S140, the center position of the circle including the arc shape detected in step S130 is stored in a memory or the like (reference point position acquisition step). As a specific example, the reference point position acquisition means 130 acquires the TCP of the hand 11 when a part of the tip (arc shape) of the hand 11 is detected by the two optical sensors 21 and 22, and stores it in a memory.

[0075] In step S150, it is determined whether a circle can be formed based on the center position saved in step S140. If it is determined that the circle can be formed ("Yes" in step S150), the process proceeds to step S160, and if it is determined that the circle cannot be formed ("No" in step S150), the process returns to step S120 and the processes of steps S120 to S150 are repeated.

[0076] For example, as explained with reference to Figures 5 and 7, a circle can be drawn uniquely with three points, but it can also be drawn with two points if the radius or diameter of the circle is known. Here, the radius of the circle is the radius r of a circle C centered on the TCP(T) of the hand 11, as shown in Figure 6, and is the length from the TCP(T) to the tips 11A and 11B of the hand 11.

[0077] In step S160, the sensor position (robot coordinate system) is calculated based on the center position (robot coordinate system) stored in step S140 (sensor position calculation step). As a specific example, the sensor position calculation means 140 calculates the center position of a circle 21C as the position (robot coordinate system) of the optical sensor 21, as shown in Fig. 7, based on the multiple TCPs (T1 to T3) of the hand 11 stored in step S140. Similarly, the sensor position calculation means 140 also calculates the position (robot coordinate system) of the optical sensor 22.

[0078] As described above, according to the robot control device 100 and the calibration method M100 according to an embodiment of the present invention, the robot control means 110 operates the transport robot 10 having the hand 11, which has a circular arc shape (tips 11A and 11B) centered on the TCP (T), toward the sensor device 20 that is fixedly arranged. The detection means 120 detects the tips 11A and 11B of the hand 11 multiple times using the two optical sensors 21 and 22 in the sensor device 20, the reference point position acquisition means 130 acquires the TCP (T1, T2, T3) at that time, and the sensor position calculation means 140 calculates the center of the circle formed based on the TCP (T1 to T3) as the position of the two optical sensors 21 and 22. This makes it possible to appropriately calculate the positional relationship between the transport robot 10 and the two optical sensors 21 and 22 in the sensor device 20.

[0079] In this embodiment, as described with reference to FIG. 7, the sensor position calculation means 140 detects the tip of the hand 11 three times with the optical sensor 21, draws a circle 21C from the three TCP points (T1 to T3) at that time, and calculates the center position of the circle 21C as the position of the optical sensor 21, but is not limited to this. For example, if the distance between the TCP of the hand 11 and the tip of the hand 11 constituting an arc shape (the radius of the circle including the arc shape centered on the TCP) is known in advance (as a fixed value), the sensor position calculation means 140 can detect the tip of the hand 11 twice with the optical sensor 21 and draw two circles from the two TCP points at that time. Then, based on the positional relationship between the optical sensor 21 and the hand 11, it is possible to select the circle drawn on the tip side of the hand 11 from the two circles. In other words, if the tip of the hand 11 is detected twice by the optical sensor 21, the sensor position calculation means 140 can calculate the position of the optical sensor.

[0080] In addition, in this embodiment, the sensor device 20 is provided with two optical sensors 21, 22, but this is not limited to this. For example, the optical sensor may be one, or three or more, and the required number of optical sensors may be provided according to the robot teaching.

[0081] Furthermore, in this embodiment, the sensor device 20 is circular, and for example, if it has the same or similar shape and weight as the wafer W actually transported by the transport robot 10, then if robot teaching is performed while holding the sensor device 20, teaching and transporting can be performed with higher accuracy.

[0082] On the other hand, the sensor device 20 is not necessarily limited to a circular shape, and may be, for example, a rectangular shape, a triangular shape, or another polygonal shape. Specifically, it is sufficient that the sensor device is disposed in accordance with the shape of a robot hand so that an optical sensor provided in the sensor device is not blocked by the robot hand when the sensor device is held by the robot hand.

[0083] Furthermore, the sensor device 20 is not limited to being placed and held by a robot hand from below, and may be in other forms. For example, if a part of a circle (arc shape) centered on the TCP is configured on a part of the robot hand, the sensor device may be held by the robot hand by sandwiching it from both sides after the calibration of the optical sensor in the sensor device is completed, or may be attached to the robot hand.

[0084] In addition, in this embodiment, the tip portions 11A, 11B of the hand 11 of the transport robot 10 to be detected by the two optical sensors 21, 22 in the sensor device 20 are arc-shaped, but this is not limited to this, and it is sufficient that a part of the hand 11 is configured to be a part of a circle (arc-shaped) centered on the TCP.

[0085] Fig. 10 is a diagram showing an example of a hand 11 that forms a part of a circle (arc shape) on both sides of the hand 11. As shown in Fig. 10, both sides 11C and 11D of the hand 11 form a part (arc shape) of a circle C with a radius r centered at TCP (T).

[0086] 11 is a diagram showing an example of a hand 11 that forms a part of a circle (arc shape) inside the hand 11. As shown in Fig. 11, a step 11E, such as a groove, is formed inside the hand 11 to form a part (arc shape) of a circle C with a radius r centered on the TCP (T). The step 11E is configured to be detectable by optical sensors 21 and 22.

[0087] In this way, in the hand 11, in addition to or instead of the tips 11A and 11B, both sides 11C and 11D and the interior (step) 11E may form an arc shape, which may be detected by the two optical sensors 21 and 22 in the sensor device 20. If the arc shape of the hand 11 can be efficiently detected by the two optical sensors 21 and 22, the positions of the two optical sensors 21 and 22 can be calculated in a short time from the TCP (two or three points) at that time.

[0088] 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 arrangements, materials, conditions, shapes, sizes, etc., are not limited to those shown as examples and can be changed as appropriate. In addition, configurations shown in different embodiments can be partially substituted or combined with each other. [Explanation of symbols]

[0089] 1...Transport robot system, 10...Transport robot, 11...Hand, 11A to 11E...Arc shape, 20...Sensor device, 21, 22...Optical sensor, 80...Sensor, 90...Center, 91 to 93...Center position, 99...Moving body, 100...Robot control device, 110...Robot control means, 120...Detection means, 130...Reference point position acquisition means, 140...Sensor position calculation means, M100...Calibration method, S110 to S160...Each step in the calibration method M100, r...Radius, W...Wafer, WS...Work space, S1 to S3...Stage, C, 21C, 80C...Circle

Claims

1. A robot control device for controlling an operation of a robot, a robot control means for controlling the robot to operate in a circular arc shape having a predetermined reference point as a center; a detection means for detecting a part of the arc shape a plurality of times by a sensor provided in a sensor device by operating the robot using the robot control means; a reference point position acquisition means for acquiring a plurality of positions of the reference point when detected by the detection means; and a sensor position calculation means for calculating a position of the sensor based on the plurality of positions. Robot control device.

2. the sensor position calculation means calculates the position of the sensor based on at least two positions of the reference point detected by the sensor and a diameter of a circle configured to include the arc shape as a part thereof; The robot control device according to claim 1 .

3. the sensor position calculation means calculates the position of the sensor based on at least three positions of the reference point when detected by the sensor; The robot control device according to claim 1 .

4. The robot control means operating the robot so as to hold the sensor device based on the position of the reference point and the position of the sensor calculated by the sensor position calculation means; determining a relative position between the position of the reference point and the position of the sensor; The robot control device according to claim 1 .

5. A calibration method executed by a robot control device that controls an operation of a robot, comprising: a robot control step of operating the robot so as to form a part of an arc shape having a predetermined reference point as a center; a detection step of detecting a part of the arc shape a plurality of times by a sensor provided in a sensor device by operating the robot in the robot control step; a reference point position acquisition step of acquiring a plurality of positions of the reference point when detected in the detection step; and calculating a position of the sensor based on the plurality of positions. Calibration method.

6. A sensor device used in a calibration method executed by a robot control device that controls the operation of a robot, The calibration method includes: a robot control step of operating the robot so as to form a part of an arc shape having a predetermined reference point as a center; a detection step of detecting a part of the arc shape a plurality of times by a sensor provided in the sensor device by operating the robot in the robot control step; a reference point position acquisition step of acquiring a plurality of positions of the reference point when detected in the detection step; and calculating a position of the sensor based on the plurality of positions. Sensor device.

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