KR20190110438A - Method for restoring position information of robot - Google Patents

Abstract

In regard to a robot including a plurality of hands, provided is a position information restoring method capable of eliminating the need for reinstruction for the exchange of devices of the robot, the reassembly of the robot, or the exchange of the robot, and also, preventing a result of calibration on a hand from influencing another hand. Before and after the exchange of a robot, starting point offsets for each hand of the robot and predetermined position coordinates for each hand, which indicate the location and posture of the robot in an external coordinate system when an arm of the robot is stretched to move a hand to a predetermined position, are acquired. A difference between the starting point offsets before and after the exchange of the robot can be called a starting point dislocation value, and a dislocation value based on a difference between the position coordinates can be called a coordinate dislocation value, so the starting point dislocation value and the coordinate dislocation value can be memorized by hand and managed separately.

Description

How to restore the position information of the robot {METHOD FOR RESTORING POSITION INFORMATION OF ROBOT}

The present invention relates to a method for restoring positional information that makes it possible to use previous teaching data in the robot when exchanging equipment in the robot, reassembling or relocating the robot, and the like.

In a robot operating on the basis of teaching (teaching) data, there are cases where replacement of equipment such as a motor, an arm, a hand, etc. constituting the robot, reassembly, or relocation of the robot itself may be performed. When the device is replaced, reassembled, or moved, the amount of error related to assembly or installation of the robot changes, so it is necessary to re-teach the robot before performing work by the robot again. However, since teaching a robot requires a lot of time and effort, it is desired that previous teaching data can be used even when the device is replaced, the robot is reassembled or moved. Patent document 1 relates to the robot which processes with respect to the workpiece hold | maintained by the holding | maintenance apparatus, and before and after moving a robot, the position of three places of the workpiece hold | maintained by the holding | maintenance apparatus or the holding apparatus is shown. Measurement is performed by a visual sensor provided on an arm of a robot, and the teaching data is corrected so as to compensate for the change in the relative position of the robot and the holding device based on the change in the measurement result before and after the robot is moved.

In robots, the position (especially the rotational position) of each axis is obtained by a sensor (for example, an encoder), but when the motor, reducer, arm, or hand are replaced, the reference position used to determine the position of each axis is shifted. . This is also the reason that the previous teaching data cannot be used after the replacement of the device, but Patent Document 2 provides a pin hole in each of a pair of structures (for example, arms) constituting the joint axis of the robot, and in each pin hole. A method of defining a reference position by inserting a penetrating pin or providing a V-shaped groove in one structure constituting the joint axis, and providing a proximity sensor corresponding to the V-shaped groove in the other structure to provide a signal from the proximity sensor. Discloses a method of specifying a reference position.

When the apparatus is replaced, the robot itself is reassembled or moved, furthermore, the robot is calibrated to cope with changes over time. In the case of calibration, the instrument parameters used to describe the robot kinematically change, and the teaching data used before calibration cannot be used as it is. Patent document 3 discloses correcting and using the teaching data based on the instrument parameter before calibration and the instrument parameter after calibration. As related to the calibration, Patent Literature 4 positions the robot so that an image of a marker installed at the tip of the robot and a virtual reference point set on the imaging surface of one camera overlap, and the motion amount and virtual reference point of each axis of the robot at that time Disclosing the correction of the error of the machine parameter of the robot based on the position in the image coordinate system.

By the way, the horizontal articulated robot among various robots is used for conveyance of a semiconductor wafer, a glass substrate, etc., for example. Patent Document 5 shows an example of a horizontal articulated robot for transporting a large article such as a glass substrate. In the robot shown in patent document 5, conveyance efficiency is improved by providing two hands for holding a glass substrate etc. These hands extend in opposite directions. With the increase in the size of the conveying object of the horizontal articulated robot and the complexity of the process performed on the conveying object, the horizontal articulated robot itself is also enlarged, and the conveying distance of the conveying object is also long. When the horizontal articulated robot became larger, there was also a need to disassemble and transport the robot once it was completed and adjusted in order to ship the robot and mount it on demand. In particular, in the case of a horizontal articulated robot used for conveying a glass substrate, since the hand becomes a large object, it is often necessary to separate the hand for transportation or relocation of the robot itself.

Japanese Patent No. 3733364 Japanese Patent No. 4819957 Japanese Patent Laid-Open No. 2017-213668 Japanese Patent Laid-Open No. 2006-110705 Japanese Patent Publication No. 2015-139854

Patent Literatures 1 to 3 disclose methods for enabling the previous teaching data to be used without re-teaching even in the case of exchanging equipment in the robot, reassembling or relocating the robot itself, and further recalibrating the robot. have. As for the method of patent documents 1-3, a set of correction data (if patent document 1 is the data regarding the shift | offset of the position with respect to the specific holding | maintenance apparatus before and after relocation, if it is patent document 2, the data which correct | amends a reference position, patent document 3, the data relating to the deviation of the mechanical parameters before and after calibration). However, when the robot is enlarged like the horizontal articulated robot for conveyance and its movement range is also increased, in the method of Patent Documents 1 to 3, the teaching data cannot be corrected sufficiently, and as a result, the re-teaching is performed. It may become unavoidable. In particular, in the case of a robot having a plurality of hands as disclosed in Patent Literature 5, the modification of the teaching data performed on one hand affects the other hand, and as a result, the other hand is appropriately moved. You may not be able to. Even if the calibration method described in Patent Literature 4 is performed, the influence of the calibration performed on one hand cannot be prevented from reaching the other hand.

An object of the present invention is to provide a robot, such as a large horizontal articulated robot for conveyance having a plurality of hands, which does not require re-teaching when exchanging a device constituting the robot, reassembling or relocating the robot, and performing hand-by-hand calibration. The present invention provides a method for restoring location information that can prevent the result from affecting other hands.

The positional information restoration method of the present invention is used in a processing apparatus having a plurality of processing chambers, and in the positional information restoration method of a robot that supports and transfers an object between a plurality of processing chambers based on the teaching data, the robot processes the processing. A base provided in the apparatus, a plurality of hands supporting the object, and at least one arm interposed between the base and the plurality of hands, and the plurality of hands are provided with a mounting portion with respect to the arm that becomes the end when viewed from the base. It is installed through a part of the robot, a part or all of the robot reassembly, or the relocation of the robot to replace the robot, and before the robot replacement is performed, the origin offset for each hand of the robot and the arm are extended to move the hand to a predetermined position. A process of storing predetermined position coordinates for each hand, which indicates the position and attitude of the robot when moved to the robot, and the robot origin after Acquiring a set for each hand, and storing each position shift amount, which is the difference between the home offset before robot exchange and the home offset after robot exchange, for each hand; and after robot replacement, the arm is extended to move the hand to a predetermined position, and the predetermined position coordinate for each hand And calculating and storing the coordinate shift amount for each hand based on the difference between the predetermined position coordinate before the robot exchange for each hand and the predetermined position coordinate after the robot exchange, and separately managing the origin shift amount and the coordinate shift amount for each hand separately. do.

In the present invention, the amount of correction used for correcting the teaching data is divided into two, the origin shift amount based on the origin offset and the coordinate shift amount based on the predetermined position coordinate, and these shift amounts are acquired for each hand and managed separately. The result of the calibration for the hand can be prevented from affecting other hands, whereby the teaching data can be appropriately modified according to the hand used in the robot so that the teaching data can be used even after the robot is replaced. . In addition, when there is an abnormality in any misalignment amount, it is possible to easily discriminate that there is an abnormality and which misalignment amount is in the abnormality. Even if data loss or the like occurs in the process of calculating the shift amount, if the shift amount of origin has been calculated, the coordinate shift amount can be calculated using the zero shift amount as it is, so that the time for calculating the correction amount can be shortened.

In the positional information restoration method of the present invention, the processing apparatus is provided with one reference marker, and at least a part of the object mounted on the hand and the reference marker are picked up by a visual sensor to acquire the position of the object, which is separate from the robot. It is preferable to acquire predetermined position coordinates in the coordinate system, for example, the coordinate system of the processing apparatus. The shift occurring in the predetermined position coordinate when moving to the predetermined position after replacing the robot is mainly caused by the shift of the position in the plane where the robot is installed and the shift of the robot's orientation (an angle shift). Since the influence of the misalignment of the orientation is greater than the misalignment of the position, if one calculates the coordinate misalignment by focusing on the misalignment of the orientation, only one reference marker may be used, and the operation for calculating the misalignment of the coordinate is concise. can do.

In the present invention, the processing apparatus is provided with two reference markers, and at least a part of the object mounted on the hand and the reference marker are picked up by the visual sensor to acquire the position of the object, whereby the predetermined position in the coordinate system separate from the robot is obtained. You may acquire the coordinates. In the case of providing two reference markers, the deviation of the position and the deviation of the angle included in the coordinate shift amount can be separated. Thus, even if there is some error in the origin offset, the correction is made based on the amount of offset and the amount of coordinate shift. The teaching data allows the robot to be accurately moved to the desired position.

In this invention, it is preferable to provide a reference marker in any one of several process chambers. In the processing apparatus, by using the reference marker provided in the processing chamber actually used, the teaching data can be corrected based on the deviation in the processing chamber actually used.

In the present invention, it is preferable to detect a hand used in the teaching data among the plurality of hands, and correct the teaching data by using the origin data and coordinate data for the detected hand. By modifying the teaching data in this way, the teaching data is corrected based on the amount of misalignment with respect to the hand actually used in the teaching data, so that the teaching data can be corrected more appropriately. At this time, the teaching data is corrected using the origin shift amount and the coordinate shift amount until the shift of the predetermined position coordinate before and after the robot replacement is within the allowable range, and the robot is determined from the origin position based on the corrected teaching data. The recalculation of the coordinate shift amount can be repeated by moving to the position. By such iterative calculation, the accuracy of correcting the teaching data can be improved.

In the present invention, the number of hands is two, for example, and the two hands are provided in the mounting portion so as to form a 180 ° positional relationship with each other. In the case where two hands are arranged in a positional relationship of 180 °, the workpiece is moved in and out by one hand with respect to one of the two processing chambers facing each other, and then the other processing chamber is moved by moving the hand without rotating the hand. It is possible to move in and out of another work, and the conveyance efficiency is improved. In the case of providing two hands and forming them at an angle of 180 ° to each other, in the teaching data, a transformation coordinate system having a forward direction in which one of the two hands extends is used, and the processing in the teaching data When the direction of movement of the hand to the chamber coincides with the positive direction of the conversion coordinate system, one hand is detected. When the direction of movement of the hand to the processing chamber in the teaching data coincides with the negative direction of the conversion coordinate system, the other hand It can be detected as being used. In this configuration, since it is possible to determine which hand is used from the movement of the hand itself in the teaching data, a sensor or the like for identifying the hand becomes unnecessary.

According to the present invention, re-teaching can be unnecessary at the time of exchanging a device constituting the robot, reassembling or relocating the robot, while preventing the calibration results for each hand from affecting other hands.

1: is a figure which shows an example of a robot, (a) is a top view, (b) is a front view, (c) is a front view of a robot in an origin position.
2 is a block diagram showing a circuit configuration of a robot and a robot controller.
FIG. 3: is a figure which shows the processing apparatus in which the robot shown in FIG. 1 is provided, (b) is a figure which shows typically the cross section of a processing chamber.
4 is a flowchart showing the operation of the method for restoring location information according to the present invention.
5 (a) and 5 (b) are diagrams for explaining the transformation coordinate system.
6 is a diagram schematically showing a processing chamber of another example.

Next, preferred embodiment of this invention is described with reference to drawings. Before explaining the position information restoration method based on this invention, an example of the robot used as the application object of a position information restoration method is demonstrated first.

1 shows an example of a robot to which a positional information restoration method based on the present invention is applied. (A), (b) is a top view and a front view which show the robot in the arm or the hand extended state. The robot shown in FIG. 1 is the same as the horizontal articulated robot for conveyance described in patent document 5, and the base 11, the 1st arm 12 provided in the base 11, and the 1st arm 12 of The 2nd arm 13 provided in the front-end, and the some hand (hand 14 and the hand 15 in the illustration) provided in the front-end | tip of the 2nd arm 13 through the installation part 16 are provided. . The hands 14 and 15 hold the glass substrate etc. which are conveyed objects, and are all formed in the fork shape. Both of the hands 14 and 15 are detachably attached to the mounting portion 16 by their base side being inserted into and fixed to the mounting portion 16. The hands 14, 15 extend in opposite directions from the mounting portion 16. The first arm 12 is rotatable about an axis A with respect to the base 11, and the second arm 13 is rotatable about an axis B with respect to the first arm 12, and the second arm ( The attachment portion 16 is rotatable around the axis S with respect to 13). The angle formed by the direction in which the hands 14 and 15 extend is set to be 180 degrees about the axis S, but in reality, the angle may not be exactly 180 degrees due to the installation error or the like.

In order to enable rotation around the axes A, B, and S, which are the joint axes of the robot, the robot is provided with a motor for each axis. Moreover, the robot is provided in the base 11, the mechanism which raises and lowers the 1st arm 12 to Z direction, and this lifting mechanism is also driven by the lifting motor. The axes A, B and S are all parallel to the Z direction. Each of the hands 14 and 15 including the base 11, arms 12 and 13 and the mounting portion 16 is a structure included in the robot. In the following description, the hands 14 and 15 are referred to as the first hand 14 and the second hand 15, respectively.

In the robot shown in FIG. 1, the origin position which becomes a reference | standard of an operation | movement of a robot is defined, and a robot becomes a predetermined folded posture with an arm or a hand at a origin position. FIG. 1C shows the posture of the robot at the origin position, and the second arm 13 and the first hand 14 overlap with each other on the first arm 12. The first hand 14 is folded. In the home position, the extending direction of the second hand 15 coincides exactly with the longitudinal direction of the second arm 13, but as described above, it is installed due to an installation error or the like with respect to the mounting portion 16. Since the angle formed by the direction in which the first hand 14 and the second hand 15 extend from the part 16 is not exactly 180 degrees, the attitude of the origin position with respect to the first hand 14 is taken. The second hand 15 cannot be said to be in the home position when there is any. Originally, the origin position should be one, but in the present embodiment, the posture in which the second arm 13 and the first hand 14 overlap on the first arm 12 is referred to as the posture of the first origin position. The posture where the 2nd arm 13 overlaps on the 1st arm 12, and the longitudinal direction of the 2nd arm and the direction in which the 2nd hand 15 extends is corresponded is called the posture of a 2nd origin position.

In order to control the robot shown in FIG. 1, the robot controller is provided. 2 illustrates an electrical circuit configuration of the robot and the robot controller 40. As described above, the robot is provided with four motors 18 for the axes A, B, S, and the lifting mechanism, but these motors 18 have an encoder 19 for measuring the rotation angle of the motor 18. Are installed respectively.

The robot controller 40 includes a bus 41 used for transmitting various signals and data, a servo circuit 42 provided for each motor 18 to drive the motor 18, and a robot for operation or control. A CPU (central processing unit) 43 for performing a necessary operation and outputting a command to each servo circuit 42, and a storage unit 44 for storing data necessary for calculation and control by the CPU 43 are provided. . The storage unit 44 includes, as a storage area or file, a teaching data storage unit 51 for storing teaching data, an origin offset storage unit 52 for storing origin offsets, and predetermined position coordinates for storing predetermined position coordinates. The storage unit 53 is set. The origin offset and the predetermined position coordinate will be described later. The servo circuit 42, the CPU 43, and the storage unit 44 are connected to the bus 41. The output from the encoder 19 is supplied to the servo circuit 42 which drives the corresponding motor 18 and is also sent to the CPU 43 via the bus 41. The teaching controller 60 used for teaching the robot and the camera 23 which are visual sensors is connected to the robot controller 40, These are connected to the bus 41 via the interface circuit which is not shown in figure.

Next, the usage form of the robot demonstrated here is demonstrated using FIG. Here, a robot is used in the processing apparatus used to manufacture a liquid crystal display or an organic EL (electroluminescence) display by performing a process such as film formation, etching, or the like on the workpiece 31 which is a substantially rectangular glass substrate. Shall be. As shown to Fig.3 (a), the processing apparatus is equipped with the conveyance chamber (transfer chamber) 21 and the some process chamber (process chamber) 22 arrange | positioned so that the conveyance chamber 21 may be enclosed. The processing chamber 22 is provided to carry in or carry out the work 31 into the manufacturing system itself, and is provided to perform film formation, etching, or other processing on the work 31. The robot is provided in the conveyance chamber 11 by providing the base 11 in the conveyance chamber 21, and conveys the workpiece | work 31 through the conveyance chamber 21 between the process chambers 22. Therefore, the robot is provided in substantially the center of the conveyance chamber 21, and either the 1st hand 14 or the 2nd hand 15 (the 1st hand is shown in the figure) at the time of delivery of the workpiece | work 31. The arms 12 and 13 are extended so that (14) enters the process chamber 22. In the robot in this embodiment, since the 1st hand 14 and the 2nd hand 15 are provided in the mutually angled angle of about 180 degrees, for example, the 1st hand 14 carries the conveyance chamber 21 with it. The work 31 is moved in and out of the processing chamber 22 on one wall of the wall), and then the hands 14 and 15 are moved without rotating the hands 14 and 15, whereby the other of the transfer chamber 21 It is possible to enter and exit the separate work 31 with respect to the separate processing chamber 22 on the side wall surface, and conveyance efficiency improves.

Among the plurality of processing chambers 22, for example, on the ceiling surface of the processing chamber 22 used for carrying in and out of the work 31 with the outside of the manufacturing system, a reference marker ( 24 is provided, and the camera 23 is provided in the bottom surface of the process chamber 22 so that the reference marker 24 may be imaged. The camera 23 is also drawn in Fig. 3A. The camera 23 and the reference marker 24 are used to determine whether the work 31 loaded on the hand 14 of the robot is loaded at the correct position on the hand 14 or the hand 15. It is used. The robot is moved to the processing chamber 22 including the camera 23 and the reference marker 24 based on the teaching data, and the edge of the work 31 is taken by the camera 23 at that time. By photographing the reference markers 24, it is possible to know whether the workpiece 31 is correctly mounted on the hand 14 or the hand 15, and in which direction and how much is displaced in the case where the workpiece 31 is displaced from the original position. When the stacking position of the workpiece 31 is shifted from the original position, the stacking position of the workpiece 31 can be corrected by a position correction device (not shown).

Next, the position information restoration method in embodiment of this invention is demonstrated. The method for restoring the positional information according to the present embodiment is performed in the robot before the replacement, reassembly, or relocation of the robot itself when the device such as the motor or the arm constituting the robot is replaced, or when the robot itself is reassembled or relocated. The teaching data used can be used even after exchange, reassembly, or relocation without re-teaching. Hereinafter, the replacement of equipment in the robot, reassembly and relocation of the robot itself will be collectively referred to as robot replacement.

As described above, the home position is a reference for the position and attitude when the robot is moved. In the robot at the home position, the rotation positions of the respective motors 18 of the robot are all considered to be zero. The rotational position of the motor 18 is measured by the encoder 19 connected to the motor 18 and output to the robot controller 40. However, depending on the assembly state of the motor 18 with respect to the arms 12 and 13 and the hand 14, and the assembling state between the motor 18 and the encoder 19, even if the robot is in the home position, the encoder 19 The value of the rotation position output from the output is not always zero. In particular, in the case of this embodiment, since two origin positions of the first origin position and the second origin position are defined for the installation error of the hands 14, 15, etc., at least one origin position corresponds to at least the axis S. The value output from (19) is a non-zero value. The rotational position measured by the encoder 19 when the robot is at the origin position is called an origin offset. As two origin positions are defined, the origin offset also becomes two values.

When the robot is moved based on the teaching data, the teaching data is compensated by the origin offset after zeroing the rotation position at the origin position, or the rotation position at the origin position is a value represented by the origin offset. The data needs to be described. In the robot in this embodiment, the workpiece 31 is transferred between the plurality of processing chambers 22 arranged around the transfer chamber 21, and the first hand 14 and the second hand 15 Even if it is located in the conveyance chamber 21 at the same time, the 1st hand 14 and the 2nd hand 15 do not move into each process chamber 22 simultaneously. When the first hand 14 is in a certain processing chamber 22, the second hand 15 is located in the transfer chamber 21, and conversely, when the second hand 15 is in a certain processing chamber 22, the first hand is located. 14 is located in the transfer chamber 21. Thus, when the first hand 14 is moved to a certain processing chamber 22 based on the teaching data, the arms 12 and 13 are folded from the state and the first hand 14 is returned to the transfer chamber 22. When the second hand 15 is moved to a certain processing chamber 22 on the basis of the teaching data, the first position and the corresponding offset of the corresponding position are used. When returning the 2nd hand 15 to the conveyance chamber 22, the 2nd origin position and the origin offset corresponding to it are used. When there is a robot exchange, for example, when the motor 18, the arms 12, 13, and the hands 14, 15 are exchanged, the value of the origin offset generally changes before and after the replacement. Therefore, in order to use the same teaching data before and after robot replacement without re-teaching, it is necessary to correct the teaching data based on the change of the origin offset by robot replacement.

When obtaining the home offset after replacing the robot, it is necessary to move the robot to the home position. At this time, since the home offset after robot replacement is still unknown, the robot cannot be moved to the home position by the home return command or the like. Therefore, the robot may be moved to the origin position using the teaching pendant while looking at the robot. In order to move the robot to the home position more accurately, for example, as described in Patent Document 2, the pin holes for regulating the posture of the robot to the posture at the home position are arms 12 and 13 and the hands 14 and 15. ), The mounting portion 16, or the like, and the jig pin is inserted into the pin hole to fix the robot at the origin position. In the case of using the jig pin, the home sensor is provided on one side of two structures (arms 12 and 13 or the hands 14 and 15) that share the joint axis separately from the encoder 19, and the home sensor on the other side. The grooves or projections to detect the pressure, roughly adjust based on the output of the origin sensor, and then finely adjust the robot slowly to the position where the jig pin is fitted into the pin hole. Can be moved to the origin position. The jig pin and the pin hole have a function of regulating the positions of the structures (here, the base 11, the arms 12 and 13 and the hands 14 and 15) included in the robot. In this embodiment, both the origin offset corresponding to the first origin position and the origin offset corresponding to the second origin position are obtained. These two origin offsets have the same value for each of axis A and axis B, but generally have different values for axis S.

However, the origin position is a state in which the arms 12, 13 and the first hand 14 of the robot are folded, and the second hand 15 extends in the extending direction of the second arm 13, Similarly, when the arm or the hand is a long robot, the hands 14 and 15 are extended by extending the arms 12 and 13 and further rotating the mounting portion 16 around the axis S only by compensating for the change in the origin offset. If you try to move by rotating, you are not just able to move exactly to the desired position. This is because the installation position and the direction of the robot may be shifted by the robot replacement, and the installation state of the hands 14 and 15 may change. Thus, in the present embodiment, the robot arms 12 and 13 and the hands 14 and 15 are extended and moved to predetermined positions based on the teaching data before and after the robot exchange. And the coordinate which shows the position and attitude of a robot is calculated | required in the external coordinate system (for example, the coordinate system defined in the process chamber 22) separate from the coordinate system of the robot itself. This coordinate is called predetermined position coordinate. Since the predetermined position coordinates are for compensating for the deviation that cannot be compensated with the origin offset, the arm 12, 13 or the hand 14, 15 is extended as much as possible and also possible from the base 11 of the robot. It is desirable to measure at a distance. Therefore, in this embodiment, the predetermined position coordinate is measured using the camera 23 and the reference marker 24 provided in the processing chamber 22. It is preferable that the camera 23 and the reference marker 24 are provided in the process chamber 22 at the side far from the conveyance chamber 21. Since it is necessary to consider the installation error of the hands 14 and 15 with respect to the mounting part 16, the predetermined position coordinate is calculated for each of the first hand 14 and the second hand 15. The camera 23 and the reference marker 24 may be provided in the single processing chamber 22, and predetermined position coordinates of the first hand 14 and the second hand 15 may be sequentially obtained, or the transfer chamber 21 may be provided. For example, a camera 23 and a reference marker 24 are provided in each of the two processing chambers 22 at opposite positions, and the first hand 14 is disposed in one of the processing chambers 22. The predetermined position coordinates regarding the second hand 15 may be obtained in the other processing chamber.

In the measurement of the predetermined position coordinates with respect to the hand 14, the measuring jig is loaded as the work 31 at the correct position of the hand 14, and the hand 14 is placed on the basis of the teaching data while the measuring jig is placed thereon. It moves to the process chamber 22, and it photographs with the camera 24 so that a measuring jig may be taken. Similarly, in the measurement of the predetermined position coordinates with respect to the hand 15, the measuring jig is placed on the correct position of the hand 15 as the work 31, the hand 15 is moved to the processing chamber 22, and the jig is taken. Photographing is performed. In this embodiment, as a measuring jig, a rectangular thing is used, for example, the edge of a jig is extracted from the image image | photographed by the camera 24, and the image of the reference marker 24 and the edge of a jig are extracted. The coordinates of the edge of the jig are obtained from the positional relationship of the images, and this is defined as the predetermined position coordinate of the robot. At this time, the position coordinates of the vertex of the measuring jig which is a rectangle may be calculated | required, and in addition to the coordinate of a vertex, you may acquire the direction of the two sides connected to a vertex as showing the attitude | position of a robot. Since the reference marker 24 is fixed to the processing chamber 22, the coordinates of the edge of the jig obtained here, that is, the predetermined position coordinates, indicate the position of the robot in the external coordinate system. The movement of the robot based on the teaching data in the measurement of the predetermined position coordinates is for excluding the influence of the backlash.

In the position information restoration method of the present embodiment, the amount of change in the home position offset before and after the robot exchange is called the origin shift amount, and the amount of change in the predetermined position coordinates before and after the robot exchange is called the coordinate shift amount. The methods described in Patent Literatures 1 and 3 are methods for measuring the equivalent of the sum of the origin shift amount and the coordinate shift amount and eventually used for correction of the teaching data, and the method described in Patent Document 2 measures the origin shift amount. It is about. In contrast, in the present embodiment, when reusing the teaching data after robot replacement, the teaching data is corrected using both the origin shift amount and the coordinate shift amount, but the origin shift amount and the coordinate shift amount are separately for each hand. Manage. In the storage unit 44, the home offset before and after the robot replacement and the amount of home deviation for each hand calculated therefrom are stored in the home offset storage unit 52, and the predetermined position coordinates before and after the robot replacement and the hand calculated therefrom. The star coordinate shift amount is stored in the predetermined position coordinate storage unit 53.

In this embodiment, managing the origin shift amount and the coordinate shift amount separately is difficult to find the abnormality even if there is an abnormality in these shift amounts when the both are managed as one thing. This is because it is difficult to verify the validity, and it is difficult to determine in which deviation amount an abnormality occurs, which in turn requires a great effort to restart the robot. The origin misalignment amount is a misalignment amount with respect to the internal coordinates of the robot itself irrespective of the external environment, and indicates how the mutual relationship between the structures constituting the robot is changed by the robot exchange. On the other hand, the coordinate shift amount may be influenced by the difference in the lengths of the arms 12 and 13 and the hands 14 and 15 before and after replacement, but in the case of a large-scale transport horizontal articulated robot, basically Indicates deviation due to a difference in the installation position and the direction of the robot. Therefore, there is no problem in managing the origin shift amount and the coordinate shift amount separately. In the process of acquiring the origin misalignment amount and the coordinate misalignment amount, even if data missing occurs due to a voltage abnormality or the like, if calculation of the origin misalignment amount is completed, it is necessary to start again from the beginning. It is possible to resume from the calculation of the coordinate shift amount using the zero shift amount already calculated as it is.

Here, the amount of coordinate shift is examined. Basically, there exists a component which arises by the shift of the installation position of a robot in the plane in which a robot is installed, and the shift of the orientation of a robot in the coordinate shift amount. The aim of this embodiment is to reuse teaching data without re-teaching after robot replacement, and when teaching data is reused, the error of the position of the hands 14 and 15 in each processing chamber 22 is within a predetermined value. It is. When the first hand 14 is noticed, a displacement of, for example, 1 mm in the installation position of the robot is only a deviation of 1 mm in the position of the first hand 14, but the arm 12 of the robot , 13) and a large transfer robot having a sum of the lengths of the first hand 14 equal to 3 m, a deviation of 0.1 ° in the orientation of the robot is approximately 5 mm at the position of the extended first hand 14. It is equivalent to misalignment. Although it is easy to make the error (deviation of the center position of a robot) of an installation position into 1 mm or less, it is difficult to make the error of an orientation into 0.1 degrees or less. Therefore, it can be considered that the coordinate shift amount corrects the shift in the orientation of the robot after robot replacement. Then, the coordinate shift amount can be obtained by a simple calculation using one reference marker 24. The teaching data can be reused by correcting the teaching data used prior to the robot replacement by using the corrected origin shift amount and the coordinate shift amount calculated using one reference marker 24.

In this embodiment, although the amount of coordinate shift | offset | difference is determined for every hand using the camera 23 and the reference marker 24 provided in a certain process chamber 22, the process chamber which provides the camera 23 and the reference marker 24 ( It is preferable that 22) is the process chamber 22 which the hand actually uses when moving a robot based on teaching data. In addition, if the coordinate shift amount is obtained from the predetermined position coordinates for each hand, the teaching shift data using the hand is corrected using the origin shift amount and the coordinate shift amount, and once returned to the origin position, then moved back to the predetermined position to move to the predetermined position. By obtaining the coordinates, if the difference between the predetermined position coordinates obtained last time and the predetermined position coordinates obtained this time is within the allowable value, the amount of coordinate shift with respect to the hand is determined; otherwise, the coordinate shift amount is updated by the predetermined position coordinates obtained this time. In addition, the correction accuracy when reusing the teaching data can be improved.

4 shows an example of processing by the positional information restoration method of the present embodiment. In FIG. 4, step 101-103 has shown the process of the preparation step before robot replacement, and step 105-116 has shown the process performed after robot replacement. In the processing performed before the robot exchange, first, in step 101, the home offset for each hand before performing the robot exchange is stored in the origin offset storage unit 52. When the robot is installed, the home position offset for each hand is usually obtained by performing the home alignment of the robot, so the value may be used. Next, in step 102, the measurement jig is provided as the workpiece 31 in the first hand 14, and the teaching data A which is the teaching data when the first hand 14 accesses the processing chamber 22 is next. The robot is moved to the predetermined position based on the above, and the edge of the jig is detected using the camera 23 and the reference marker 24 to obtain the predetermined position coordinates. The predetermined position coordinates obtained here are referred to as position P1 with respect to the first hand 14 and are stored in the predetermined position coordinate storage unit 53. In the same manner, in step 103, the measurement jig is provided as the workpiece 31 in the second hand 15, and the teaching data B which is the teaching data when the second hand 15 accesses the processing chamber 22 is provided. On the basis of this, the robot is moved to the above-described predetermined position, and the edge of the jig is detected using the camera 23 and the reference marker 24 to obtain the predetermined position coordinates. The predetermined position coordinates obtained here are referred to as position P2 with respect to the second hand 15 and are stored in the predetermined position coordinate storage unit 53.

After execution of step 103, in step 104, the robot is replaced, that is, a device such as a motor, an arm, a hand, etc. in the robot is replaced, and the robot itself is reassembled or relocated.

After completion of the robot exchange, in step 105, the robot is mechanically moved to the first home position corresponding to the first hand 14 and the second home position corresponding to the second hand 15, in each case. The home position offset after robot replacement is obtained and stored in the home position offset storage unit 52. In step 106, the difference in the home offset before and after the robot replacement for each hand stored in the home offset storage 52 is obtained as the home deviation amounts D1 and D2 and stored in the home offset storage 52. The difference between the home offsets with respect to the first hand 14 is the origin shift amount D1, and the difference between the home offsets with respect to the second hand 15 is the origin shift amount D2. Subsequently, in Step 107, the same measuring jig as used in Step 102 is mounted on the first hand 14, and the teaching data A modified in consideration of the origin shift amount D1, that is, based on the origin shift amount D1, is obtained. To move the robot to a predetermined position. In the same manner as described above, the predetermined position coordinates are obtained, and the predetermined position coordinates at this time are stored in the predetermined position coordinate storage unit 53 as the position Q1. Next, in step 108, the coordinate shift amount E1 for the first hand 14 is obtained from the difference between the position P1 and the position Q1, and stored in the predetermined position coordinate storage unit 53.

Subsequently, in step 109, the robot is moved to the first origin position by a command input to the robot controller 40, and thereafter, based on the origin shift amount D1 and the coordinate shift amount E1 with respect to the first hand 14. Using the modified teaching data A, the robot is moved from the first origin position to the predetermined position, the predetermined position coordinates are obtained in the same manner as described above, and the predetermined position coordinates at this time are designated as the position R1. Remember it. In step 110, it is determined whether or not the difference between the position P1 determined before robot replacement and the position R1 obtained this time exceeds the allowable value. When the allowable value is exceeded, since the coordinate shift amount E1 for the first hand 14 is not required with high precision, in step 111, the coordinate shift amount E1 is recalculated based on the difference between the position P1 and the position R1. The data is stored in the predetermined position coordinate storage unit 53. In the recalculation of the coordinate shift amount E1, a deviation exceeding the allowable value has occurred between the position P1 and the position R1 in the coordinate shift amount E1 before the recalculation, so that the value for correcting the coordinate shift amount E1 is corrected so as to eliminate this shift. The calculation is performed. After execution of step 111, it returns to step 109 and repeats the process of step 109 from step 109 until the difference of the position P1 and the position R1 becomes within a tolerance value. If the difference between the position P1 and the position R1 is within the allowable value in step 110, the coordinate shift amount E1 with respect to the first hand 14 is determined, and the process proceeds to step 112.

When the coordinate shift amount E1 with respect to the first hand 14 is determined, the coordinate shift amount E2 with respect to the second hand 15 is subsequently determined by the same procedure. In step 112, the same measuring jig as used in step 103 is mounted on the second hand 15, the robot is moved to a predetermined position using the teaching data B modified based on the origin shift amount D2, and the predetermined position coordinates are used. Is obtained, and the predetermined position coordinates at this time are stored in the predetermined position coordinate storage unit 53 as the position Q2. In step 113, the coordinate shift amount E2 regarding the 2nd hand 15 is calculated | required from the difference of the position P2 and the position Q2, and stored in the predetermined position coordinate storage part 53. As shown in FIG. Next, in step 114, the robot is moved to the second home position by a command input, and then the teaching data B modified based on the origin shift amount D2 and the coordinate shift amount E2 with respect to the second hand 15 is changed. The robot is moved from the second origin position to the predetermined position to obtain predetermined position coordinates, and the predetermined position coordinates at this time are stored in the predetermined position coordinate storage unit 53 as the position R2. In step 115, it is determined whether or not the difference between the position P2 obtained before robot replacement and the position R2 obtained this time exceeds the allowable value. When the allowable value is exceeded, a calculation is performed in step 116 to calculate a value for correcting the coordinate shift amount E2 so as to resolve this difference based on the difference between the position P2 and the position R2. After execution of step 116, it returns to step 114 and repeats the process of step 116 from step 114 until the difference of the position P2 and the position R2 becomes within a tolerance value. In step 115, if the difference between the position P2 and the position R2 is within the allowable value, the coordinate shift amount E2 for the second hand 15 is also determined, and the process of position information restoration is terminated.

As described above, after the origin shift amount and the coordinate shift amount are determined for each hand and stored in the origin offset storage 52 and the predetermined position coordinate storage 53, respectively, the teaching data used before replacing the robot is used. By correcting based on the origin shift amount and the coordinate shift amount, the teaching data can be continuously used even after the robot is replaced. In the correction of the teaching data, the origin shift amount and coordinate corresponding to the hand to be used, depending on which of the first hand 14 and the second hand 15 is used to access the processing chamber 22. Use the shift amount to correct the teaching data. Therefore, it is necessary to determine which hand is used. Hereinafter, the detection method of the hand used is demonstrated.

The transfer robot shown in the present embodiment is used to allow the workpiece 31 to enter and exit the processing chamber 22, but the hands 14 and 15 and the workpiece 31 held therein are used to carry the workpiece 31 of the transfer chamber 21. In order to avoid colliding with the wall surface, the rotation around the axis S of the hands 14 and 15 is performed when the axis S is at the center of the transfer chamber 21, in other words, when the robot is at or near the origin position. Is done. When the directions of the hands 14 and 15 are determined by the rotation around the axis S, the robot moves thereafter so that the hands 14 and 15 move in parallel with the coordinate system of the transfer chamber 21, and in particular, the processing chamber ( When the workpiece | work 31 enters and exits with respect to 22, the hands 14 and 15 move linearly with respect to the process chamber 22 from the front direction of the process chamber 22. FIG. Therefore, in the present embodiment, in the robot, a transformed coordinate system X 'Y' in which the direction in which the hands 14 and 15 extend is Y 'axis, apart from the XY coordinate system which is a rectangular coordinate system fixed to the base 11. Coordinate system). 5 is a diagram illustrating a transformed coordinate system, and illustrates a relationship between the transformed coordinate system and a rectangular coordinate system (XY coordinate system) fixed to the base 11. In the figure, the base 11 is not shown, and the arms 12 and 13 and the hands 14 and 15 are shown by bold lines. Point C in the figure is a position where the mounting portion 16 is connected to the axis S, and serves as a rotation center when the hands 14 and 15 rotate, and the arms 12 and 13 of the robot can be moved. This is the point to be controlled. The origin O of the XY coordinate system is at the position of axis A (see FIG. 1), which is a joint axis between the base 11 and the first arm 12. Since the base 11 is fixed to the conveyance chamber 21, it can be said that XY coordinate system is also fixed to the conveyance chamber 21 except for contributions, such as the error of the installation position of a robot. On the other hand, the transformation coordinate system is a rectangular coordinate system whose origin coincides with the origin O of the XY coordinate system, and the direction of the Y 'axis coincides with the direction in which one of the hands 14 and 15 extends. There are two determination methods in the transformation coordinate system depending on whether the direction in which the first hand 14 extends is in the Y 'axis direction or the direction in which the second hand 15 extends in the Y' direction. FIG. 5A illustrates a case where the direction in which the first hand 14 extends is defined as the Y 'axis direction, and FIG. 5B illustrates a direction in which the second hand 15 extends in the Y' axis direction. The case is shown.

In the present embodiment, after the hands 14 and 15 are rotated around the axis S in the origin position or in the vicinity of the robot, the hands 14 and 15 move in parallel with the coordinate system of the transfer chamber 21. It is only. Therefore, in the teaching data, the movement from the origin position toward the processing chamber 22 and the movement returned from the processing chamber 22 to the origin position include the point C as the control target point, and the movement instruction for this point is converted to the coordinate system X '. Y 'coordinate system). By using the transformed coordinate system, the movement when moving the hands 14 and 15 into or out of the process chamber 22 is indicated by addition or subtraction of the Y 'coordinate value of the point C coordinate. do. As shown in Fig. 5A, when the direction in which the first hand 14 extends is determined as the Y 'axis direction, the moving direction of the first hand 14 to a certain processing chamber 22 is the Y' axis. In the forward direction, while the first hand 14 moves from the origin position to the processing chamber 22 and while returning from the processing chamber 22 to the origin position, the Y 'coordinate value of the coordinate of the point C is positive. . In addition, in the case of FIG. 5A, the moving direction of the second hand 15 to a certain processing chamber 22 becomes the negative direction of the Y 'axis, and the second hand 15 is located at a certain processing chamber 22 from the origin position. The Y 'coordinate value of the coordinate of the point C is negative while moving to) and while returning to the origin position from the processing chamber 22. Similarly, as shown in Fig. 5B, when the direction in which the second hand 15 extends is determined as the Y 'axis direction, the first hand 14 moves to access a certain processing chamber 22. In the equation, the Y 'coordinate value of the coordinate of the point C is negative, and the Y' coordinate value of the coordinate of the point C is positive in the motion of accessing a certain processing chamber 22 by the second hand 15. Thus, by discriminating whether the Y 'coordinate value of the coordinate of the point C to be controlled in the teaching data is positive or not, the sensor or the like is not provided to the robot, so that any one of the hands 14 and 15 is used in the processing chamber 22. You can determine if you want to access it.

[Effect of Embodiment]

According to the embodiment described above, in the robot having a plurality of hands, each deviation is calculated for each hand separately by calculating, storing, and managing the origin shift amount based on the origin offset and the coordinate shift amount based on the predetermined position coordinate. While it is possible to reliably detect an abnormality in the quantity, the teaching data is corrected using the origin shift amount and the coordinate shift amount for each hand, so that re-teaching is not performed and the calibration result for each hand affects another hand. The teaching data used before replacing the robot can be used even after replacing the robot. In addition, although the robot controller 40 shown in FIG. 2 makes it possible to manage origin offset and predetermined position coordinate separately, since the hardware structure is not different from a general robot controller, the position information restoration method of this embodiment is This can be achieved using a general robot controller.

[Other Embodiments]

In the position information restoration method described above, the predetermined position coordinates are obtained by using one reference marker 24 provided in the processing chamber 22, but the installation position is achieved by using two reference markers 24 provided in the processing chamber 22. The misalignment and the misalignment of the alignment can be obtained separately, and the amount of coordinate misalignment can be obtained with high accuracy in a short time. FIG. 6 shows an example in which two reference markers 24 are provided in the processing chamber 22, and the camera 23 is disposed corresponding to each of the two reference markers 24. When the predetermined position coordinates are obtained by using the two reference markers 24, since the deviation of the installation position and the deviation of the orientation can be obtained separately, the value obtained by performing only rough adjustment by the origin sensor is obtained for the origin deviation amount. Even if used, the robot can be moved with sufficient precision when the teaching data is reused. If the camera 23 having a sufficiently wide field of view can be used, the two reference markers 24 can be photographed so that the measuring jig is taken using the single camera 23, and the mounting position is shifted from the captured image. The shift of an orientation and an orientation can be acquired separately. If the rectangular jig for measurement is used, when using the two reference markers 24, the reference markers 24 may be disposed corresponding to each of the vertices on both sides of one diagonal of the jig. By doing in this way, since the distance between two positions which detect the edge of a jig can be lengthened, the deviation of an orientation can be detected with high precision.

The robot shown in FIG. 1 is a horizontal articulated robot in which the arms 12 and 13 and the hand 14 are connected to the base 11 in this order, but the robot to which the positional information restoration method of the present invention can be applied is limited thereto. It doesn't happen. For example, the base, the base side link connected to the base, the arm side link connected to the tip of the base side link, the arm connected to the tip of the arm side link, the hand connected to the tip of the arm, provided in the base The present invention is also applicable to a horizontal articulated robot provided with a mechanism for elevating a base side link and whose tip movement of the female side link is restricted by the link mechanism. Furthermore, the present invention is also applicable to a vertical articulated robot.

11: base
12, 13: cancer
14, 15: hand
16: mounting section
18: motor
19: Encoder
21: Return Office
22: treatment chamber
23: camera
24: reference marker
31: Walk
40: robot controller
41: bus
42: servo circuit
43: CPU
44: memory
51: teaching data storage unit
52: origin offset storage
53: predetermined position coordinate storage unit
60: teaching pendant

Claims (10)

In the method for restoring the positional information of a robot, which is used in a processing apparatus having a plurality of processing chambers, and supports an object and conveys it between the plurality of processing chambers based on the teaching data.
The robot has a base provided in the processing apparatus, a plurality of hands supporting the object, and at least one arm interposed between the base and the plurality of hands,
The said plurality of hands are provided through the installation part with respect to the said arm which becomes an end seen from the said base,
Partial replacement of the robot, reassembly of part or all of the robot, or relocation of the robot is performed by replacing the robot, and before performing the robot replacement, the home offset for each of the robot and the arm are extended to the hand. Storing the predetermined positional coordinates for each of the hands, which indicate the position and attitude of the robot when it moves to a predetermined position;
After the robot replacement, acquiring the home offset of the robot for each of the hands, and storing, by the hand, an amount of home deviation that is a difference between the home offset before the robot replacement and the home offset after the robot replacement;
After the robot exchange, the arm is extended to move the hand to the predetermined position to obtain the predetermined position coordinates for each of the hands, and the predetermined position coordinates before the robot exchange for each hand and the predetermined position coordinates after the robot exchange. Calculating and storing a coordinate shift amount for each hand based on the difference
To have,
And the origin shift amount and the coordinate shift amount separately for each of the hands. 2. The robot according to claim 1, wherein the processing apparatus includes one reference marker, and at least a part of the object mounted on the hand and the reference marker are picked up by a visual sensor to acquire the position of the object. The positional information restoration method which acquires the said predetermined positional coordinate in a separate coordinate system. 2. The robot according to claim 1, wherein the processing apparatus includes two reference markers, and at least a part of the object mounted on the hand and the reference marker are captured by a visual sensor to acquire the position of the object. The positional information restoration method which acquires the said predetermined positional coordinate in a separate coordinate system. The position information restoration method according to claim 1, wherein the reference marker is provided in any one of the plurality of processing chambers. The teaching data according to any one of claims 1 to 4, wherein a hand used in the teaching data is detected from among the plurality of hands, and the teaching data is obtained by using the origin data and the coordinate data for the detected hand. To fix, location information restore method. The said teaching data after correction | amendment by correcting the said teaching data using the said origin shift amount and the said coordinate shift amount until the shift of the said predetermined position coordinate before and after the said robot exchange is in a tolerance range. And recalculating the coordinate misalignment amount by moving the robot from an origin position to the predetermined position based on. The position information restoration method according to claim 5, wherein the number of the hands is two, and the two hands are provided in the mounting portion so as to form a positional relationship of 180 degrees with each other. 8. The transformation coordinate system according to claim 7, wherein in the teaching data, a transformed coordinate system in which the direction in which one of the two hands extends is used as the forward direction is used,
When the direction of movement of the hand to the processing chamber in the teaching data coincides with the forward direction of the conversion coordinate system, the one hand is detected as the used hand,
And the other hand is detected as the used hand when the direction of movement of the hand to the processing chamber in the teaching data coincides with the negative direction of the conversion coordinate system. The position information restoration method according to claim 6, wherein the number of the hands is two, and the two hands are provided in the mounting portion so as to form a positional relationship of 180 degrees with each other. 10. The transformation coordinate system according to claim 9, wherein in the teaching data, a transformation coordinate system in which the one of the two hands extends in the forward direction is used,
When the direction of movement of the hand to the processing chamber in the teaching data coincides with the forward direction of the conversion coordinate system, the one hand is detected as the used hand,
And the other hand is detected as the used hand when the direction of movement of the hand to the processing chamber in the teaching data coincides with the negative direction of the conversion coordinate system.

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