JP7097722B2 - How to restore the location information of the robot - Google Patents

Description

The present invention relates to a position information restoration method that enables a previously taught data to be used by a robot when exchanging equipment in the robot, reassembling or relocating the robot, and the like.

In a robot that operates based on teaching data, devices such as motors, arms, and hands that make up the robot may be replaced, and the robot itself may be reassembled or relocated, if necessary. When the equipment is replaced, reassembled, or relocated, the amount of error related to the assembly and installation of the robot changes, so it is necessary to re-teach the robot before performing work with the robot again. However, since it takes a lot of time and labor to teach a robot, it is desired that the previous teaching data can be used even when the equipment is replaced, the robot is reassembled or relocated. Patent Document 1 relates to a robot that processes a work held by a holding device, and attaches three positions of the holding device or the work held by the holding device to the arm of the robot before and after the robot is relocated. It discloses that the teaching data is modified so that the change in the relative position between the robot and the holding device is compensated based on the change in the measurement result before and after the relocation of the robot by measuring with the visual sensor.

In a robot, the position of each axis (especially the rotation position) is obtained by a sensor (for example, an encoder), but when the motor, reducer, arm, or hand is replaced, the standard used to determine the position of each axis. The position will shift. This is also the reason why the previous teaching data cannot be used after the equipment is replaced. However, in Patent Document 2, pin holes are provided in each pair of structures (for example, an arm) constituting the joint axis of the robot. A method of defining a reference position by inserting a pin penetrating into each pin hole, or a proximity sensor corresponding to a V-shaped groove in one structure that constitutes a joint axis and a V-shaped groove is provided in the other structure. Discloses a method of specifying a reference position by a signal from a proximity sensor.

When the equipment is replaced, the robot itself is reassembled or relocated, and the robot is calibrated in order to cope with changes over time. When calibration is performed, the mechanical 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 that the teaching data is modified and used based on the mechanism parameters before calibration and the mechanism parameters after calibration. As related to calibration, Patent Document 4 positions the robot so that the virtual reference point set on the image pickup surface of one camera and the image of the marker attached to the tip of the robot overlap with each other. It discloses that the error of the mechanical parameters of the robot is calibrated based on the amount of movement of each axis of the robot and the position of the virtual reference point in the image coordinate system.

By the way, among various robots, the horizontal articulated robot is used for transporting, for example, a semiconductor wafer or a glass substrate. Patent Document 5 shows an example of a horizontal articulated robot for transporting a large article such as a glass substrate. The robot shown in Patent Document 5 is provided with two hands for holding a glass substrate or the like to improve the transport efficiency. These hands extend in opposite directions. With the increase in the size of the object to be transported by the horizontal articulated robot and the complexity of the process performed on the object to be transported, the size of the horizontal articulated robot itself has also increased, and the transport distance of the object to be transported has also become long. .. As the size of the horizontal articulated robot becomes larger, in order to ship the robot and install it at the demand destination, it becomes necessary to complete and adjust the robot, disassemble the robot once, transport it, and reassemble it at the installation destination. ing. In particular, in the case of a horizontal articulated robot used for transporting a glass substrate, the hand becomes long, so it is often necessary to remove the hand in order to transport or relocate the robot itself.

Japanese Patent No. 3733364 Japanese Patent No. 481995 Japanese Unexamined Patent Publication No. 2017-213668 Japanese Unexamined Patent Publication No. 2006-11705 Japanese Unexamined Patent Publication No. 2015-139854

Patent Document 1-3 makes it possible to use the previous teaching data without re-teaching even when the equipment in the robot is replaced, the robot itself is reassembled or relocated, and the robot is recalibrated. The method is disclosed. In each of the methods of Patent Document 1-3, a set of correction data (data relating to a position shift regarding a specific holding device before and after relocation in the case of Patent Document 1, and data relating to a reference position in the case of Patent Document 2) are used. In the case of Patent Document 3, it depends on the data regarding the deviation of the mechanical parameters before and after the calibration). However, when the robot becomes large and its moving range becomes large like a horizontal articulated robot for transportation, the teaching data can be sufficiently corrected by the method of Patent Document 1-3. It cannot be done, and as a result, it may be forced to re-teach. In particular, in the case of a robot having a plurality of hands as shown in Patent Document 5, the modification of the teaching data performed on any one hand affects the other hands, and as a result, the other hands. You may not be able to move your hand properly. Even if the calibration method as described in Patent Document 4 is carried out, it is not possible to prevent the influence of the calibration performed on one hand on the other hand.

An object of the present invention is that in a robot such as a large horizontal articulated robot for transportation equipped with a plurality of hands, re-teaching is not required when exchanging the equipment constituting the robot, reassembling or relocating the robot, and for each hand. The purpose is to provide a position information restoration method that can prevent the calibration result from affecting other hands.

The position information restoration method of the present invention is used in a processing apparatus having a plurality of processing chambers, and is a method of restoring the position information of a robot that supports an object and conveys it between a plurality of processing chambers based on teaching data. The robot comprises a base installed in a processing device, a plurality of hands supporting an object, and at least one arm intervening between the base and the plurality of hands. , It is attached to the arm that is the end when viewed from the base via the attachment part, and the robot is replaced by replacing a part of the robot, reassembling a part or all of the robot, or relocating the robot as a robot replacement. Before executing, the process of memorizing the origin offset for each hand of the robot and the predetermined position coordinates for each hand indicating the position and posture of the robot when the arm is extended and the hand is moved to the predetermined position, and the robot exchange After that, the process of acquiring the origin offset of the robot for each hand and storing the amount of origin deviation, which is the difference between the origin offset before the robot exchange and the origin offset after the robot exchange, for each hand, and the arm after the robot exchange. Extend and move the hand to a predetermined position to obtain the predetermined position coordinates for each hand, and the coordinates for each hand based on the difference between the predetermined position coordinates before the robot exchange for each hand and the predetermined position coordinates after the robot exchange. It has a process of calculating and storing the deviation amount, and manages the origin deviation amount and the coordinate deviation amount separately for each hand.

In the present invention, the correction amount used for correcting the teaching data is divided into two, an origin deviation amount based on the origin offset and a coordinate deviation amount based on predetermined position coordinates, and these deviation amounts are acquired for each hand and managed separately. Therefore, it is possible to prevent the result of calibration for one hand from affecting another hand, thereby appropriately teaching according to the hand used in the robot so that the teaching data can be used even after the robot is replaced. It will be possible to modify the data. Further, when there is an abnormality in any of the deviation amounts, it is possible to easily determine whether the abnormality is present and in which deviation amount the abnormality is. Even if data loss occurs in the process of calculating the amount of deviation, if the calculation of the amount of origin deviation is completed, the amount of origin deviation can be used as it is to calculate the amount of coordinate deviation. You can shorten the time for

In the position information restoration method of the present invention, the processing device is provided with one reference marker, and at least a part of the object mounted on the hand and the reference marker are imaged by a visual sensor to acquire the position of the object. It is preferable to acquire predetermined position coordinates in a coordinate system separate from that of the processing device, for example, the coordinate system of the processing device. The deviation that occurs in the predetermined position coordinates when moving to the predetermined position after replacing the robot is mainly caused by the deviation of the position in the plane where the robot is installed and the deviation of the direction of the robot (the deviation of the angle), but in a large robot Since the effect of the misalignment is greater than the misalignment of the position, if the amount of coordinate misalignment is calculated by focusing on the misalignment, it is sufficient to use only one reference marker, and the amount of coordinate misalignment is calculated. The operation for can be simplified.

In the present invention, the processing device is provided with two reference markers, and at least a part of the object mounted on the hand and the reference marker are imaged by a visual sensor to acquire the position of the object, so that the coordinates are different from those of the robot. Predetermined position coordinates in the system may be acquired. When two reference markers are provided, the positional deviation included in the coordinate deviation amount and the angle deviation can be separated, so even if there is some error in the origin offset, the origin deviation amount and the coordinate deviation amount can be set. Based on the modified teaching data, the robot can be accurately moved to the desired position.

In the present invention, it is preferable to provide a reference marker in any one of the plurality of treatment chambers. By using the reference marker provided in the processing chamber actually used in the processing apparatus, it becomes possible to correct the teaching data 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 a plurality of hands and correct the teaching data by using the origin deviation amount and the coordinate deviation amount with respect to the detected hand. By modifying the teaching data in this way, the teaching data will be modified based on the amount of deviation related to the hand actually used in the teaching data, so that the teaching data can be modified more appropriately. Become. At this time, the teaching data is corrected using the origin deviation amount and the coordinate deviation amount until the deviation of the predetermined position coordinates before and after the robot replacement is within the allowable range, and the robot is moved to the origin position based on the corrected teaching data. It is possible to repeat the process of recalculating the amount of coordinate deviation by moving the data to a predetermined position. By such repeated calculations, the accuracy of correcting the teaching data can be improved.

In the present invention, the number of hands is, for example, two, and the two hands are attached to the mounting portion so as to form a positional relationship of 180 ° with each other. When two hands are provided so as to have a positional relationship of 180 °, the work is taken in and out of one of the two opposing processing chambers by one hand, and then the hand is rotated. By moving the hand without making it move, another work can be taken in and out of the other processing chamber, and the transport efficiency is improved. When two hands are provided so as to form an angle of 180 ° with each other, a transformation coordinate system is used in which the direction in which one of the two hands extends is the positive direction in the teaching data. When the moving direction of the hand to the processing chamber in the teaching data matches the positive direction of the transformed coordinate system, it is detected that one hand is used, and the moving direction of the hand to the processing chamber in the teaching data is changed. When it coincides with the negative direction of the transformed coordinate system, it can be detected that the other hand is used. In this configuration, it is possible to determine which hand is used from the movement of the hand itself in the teaching data, so that a sensor or the like for identifying the hand is not required.

According to the present invention, it is possible to prevent the calibration result for each hand from affecting other hands, and to eliminate the need for re-teaching when exchanging the equipment constituting the robot, reassembling or relocating the robot. ..

It is a figure which shows an example of a robot, (a) is a plan view, (b) is a front view, (c) is a front view of a robot at the origin position. It is a block diagram which shows the circuit structure of a robot and a robot controller. It is a figure which shows the processing apparatus provided with the robot shown in FIG. 1, and (b) is the figure which shows the cross section of the processing chamber schematically. It is a flowchart which shows the operation of the position information restoration method based on this invention. (A) and (b) are diagrams for explaining the transformation coordinate system. It is a figure which shows typically the processing chamber of another example.

Next, a preferred embodiment of the present invention will be described with reference to the drawings. Before explaining the position information restoration method based on the present invention, first, an example of a robot to which the position information restoration method is applied will be described.

FIG. 1 shows an example of a robot to which the position information restoration method based on the present invention is applied. 1 (a) and 1 (b) are a plan view and a front view showing a robot in a state where an arm and a hand are extended. The robot shown in FIG. 1 is similar to the horizontal articulated robot for transportation described in Patent Document 5, and includes a base 11, a first arm 12 attached to the base 11, and a first arm. A second arm 13 attached to the tip of the arm 12 and a plurality of hands (hands 14 and 15 in the figure) attached to the tip of the second arm 13 via a mounting portion 16 are provided. The hands 14 and 15 hold a glass substrate or the like which is an object to be conveyed, and both are formed in a fork shape. Both the hands 14 and 15 are detachably attached to the attachment portion 16 by inserting and fixing the root side thereof to the attachment portion 16. The hands 14 and 15 extend in opposite directions when viewed from the mounting portion 16. The first arm 12 is rotatable about the axis A with respect to the base 11, the second arm 13 is rotatable about the axis B with respect to the first arm 12, and is rotatable with respect to the second arm 13. The mounting portion 16 is rotatable around the axis S. The angle formed by the extending directions of the hands 14 and 15 is set to be 180 ° with respect to the axis S, but in reality, it may not be exactly 180 ° due to the influence of mounting errors and the like. There is sex.

The robot is equipped with a motor for each axis in order to enable rotation around the axes A, B, and S, which are the joint axes of the robot. Further, the robot is provided with a mechanism provided on the base 11 to raise and lower the first arm 12 in the Z direction shown in the drawing, and this raising and lowering mechanism is also driven by the raising and lowering 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, the arms 12, 13 and the mounting portion 16 is a structure included in the robot. In the following description, the hands 14 and 15 will be referred to as a first hand 14 and a second hand 15, respectively.

The robot shown in FIG. 1 has an origin position that is a reference for the operation of the robot. At the origin position, the robot has an arm and a hand in a predetermined folded posture. FIG. 1 (c) shows the posture of the robot at the origin position, and the second arm 13 and the first hand 14 are folded so that the second arm 13 and the first hand 14 overlap on the first arm 12. ing. At the origin position, the extending direction of the second hand 15 is exactly the same as the longitudinal direction of the second arm 13, but as described above, due to an attachment error to the attachment portion 16, the attachment portion 16 is used. Since the angle formed by the extending directions of the first hand 14 and the second hand 15 is not always exactly 180 °, the second hand 15 is in the position of the origin position with respect to the first hand 14. It is not always in the origin position. Originally, there should be only one origin position, but in this embodiment, the posture in which the second arm 13 and the first hand 14 are overlapped on the first arm 12 is defined as the posture of the first origin position. The posture in which the second arm 13 is overlapped on the one arm 12 and the longitudinal direction of the second arm and the extending direction of the second hand 15 coincide with each other is defined as the posture of the second origin position.

A robot controller is provided to control the robot shown in FIG. FIG. 2 shows the electrical circuit configuration of the robot and the robot controller 40. As described above, the robot is provided with a total of four motors 18 for the axes A, B, S and the elevating mechanism. These motors 18 have an encoder that measures the rotation angle of the motor 18. 19 are attached to each.

The robot controller 40 performs calculations necessary for the operation and control of the robot, the bus 41 used for transmitting various signals and data, the servo circuit 42 provided for each motor 18 and driving the motor 18. Each servo circuit 42 includes a CPU (central processing unit) 43 that outputs commands, and a storage unit 44 that stores data necessary for calculation and control by the CPU 43. The storage unit 44 includes a teaching data storage unit 51 that stores teaching data as a storage area or a file, an origin offset storage unit 52 that stores the origin offset, and a predetermined position coordinate storage unit 53 that stores predetermined position coordinates. It is set. The origin offset and predetermined position coordinates 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 that drives the corresponding motor 18, and is also sent to the CPU 43 via the bus 41. A camera 23, which is a visual sensor, and a teaching pendant 60 used for teaching the robot are connected to the robot controller 40, and these are connected to the bus 41 via an interface circuit (not shown).

Next, the usage mode of the robot described here will be described with reference to FIG. Here, the robot is used in a processing device used to manufacture a liquid crystal display or an organic EL (electroluminescence) display by performing processing such as film formation and etching on a work 31 which is a substantially rectangular glass substrate. It shall be done. As shown in FIG. 3A, the processing apparatus includes a transfer chamber (transfer chamber) 21 and a plurality of processing chambers (process chambers) 22 arranged so as to surround the transfer chamber 21. The processing chamber 22 is provided for carrying in and out of the work 31 to the manufacturing system itself, and is provided for performing film formation, etching, and other processing on the work 31. The robot is provided in the transport chamber 11 by installing the base 11 in the transport chamber 21, and transports the work 31 between the processing chambers 22 via the transport chamber 21. Therefore, the robot is provided in the center of the transport chamber 21, and when the work 31 is delivered, either the first hand 14 or the second hand 15 (the first hand 14 in the figure) is in the processing chamber 22. Extend the arms 12 and 13 so that they can enter. In the robot of the present embodiment, the first hand 14 and the second hand 15 are provided so as to form an angle of approximately 180 ° with each other. Therefore, for example, the first hand 14 is used on one wall surface of the transport chamber 21. By moving the work 31 in and out of a certain processing chamber 22 and then moving the hands 14 and 15 without rotating the hands 14 and 15, the work 31 is moved to another processing chamber 22 on the other wall surface of the transport chamber 21. It becomes possible to put in and take out another work 31, and the transport efficiency is improved.

As shown in FIG. 3B, a reference marker 24 is attached to the ceiling surface of the processing chamber 22 used for carrying in / out the work 31 to and from the outside of the manufacturing system among the plurality of processing chambers 22. A camera 23 is provided on the floor surface of the processing chamber 22 so as to photograph the reference marker 24. The camera 23 is also depicted in FIG. 3 (a). The camera 23 and the reference marker 24 are used to determine whether the work 31 placed on the robot's hand 14 is placed in the correct position on the hand 14 or the hand 15. The robot is moved to the processing chamber 22 provided with the camera 23 and the reference marker 24 based on the teaching data, and at that time, the reference marker 24 is photographed so that the edge of the work 31 is reflected by the camera 23. Therefore, it is possible to know whether or not the work 31 is correctly placed on the hand 14 or the hand 15, and in what direction and how much the work 31 is displaced from the original position. When the mounting position of the work 31 deviates from the original position, the mounting position of the work 31 can be corrected by a position correction device (not shown).

Next, the position information restoration method in the embodiment of the present invention will be described. The position information restoration method of the present embodiment is to replace, reassemble, or relocate the robot itself when the equipment such as the motor or arm constituting the robot is replaced, or when the robot itself is reassembled or relocated. The teaching data previously used in the robot can be used after replacement, reassembly, and relocation without re-teaching. In the following, the replacement of equipment in a robot, the reassembly and relocation of the robot itself will be collectively referred to as robot replacement.

As described above, the origin position serves as a reference for the position and posture when the robot is moved, and in the robot at the origin position, the rotation position of each motor 18 of the robot is 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 assembled state of the motor 18 with respect to the arms 12 and 13 and the hand 14, and the assembled state between the motor 18 and the encoder 19, the value of the rotation position output from the encoder 19 is zero even if the robot is in the origin position. It is not always the case. In particular, in the case of the present embodiment, since the two origin positions of the first origin position and the second origin position are defined due to the mounting error of the hands 14 and 15, at least one origin position corresponds to at least the axis S. The value output from the encoder 19 is a non-zero value. The rotation position measured by the encoder 19 when the robot is at the origin position is called the origin offset. With the definition of two origin positions, the origin offset also has two values.

When moving the robot based on the teaching data, compensation is performed by the origin offset after assuming that the rotation position at the origin position is zero in the teaching data, or the rotation position at the origin position is the origin offset. It is necessary that the teaching data is described as a value to be shown. The robot in the present embodiment transfers the work 31 between a plurality of processing chambers 22 arranged around the transport chamber 21, and the first hand 14 and the second hand 15 are simultaneously in the transport chamber 21. Although they may be located, the first hand 14 and the second hand 15 do not move into the respective processing chambers 22 at the same time. When the first hand 14 is in any of the processing chambers 22, the second hand 15 is located in the transport chamber 21, and conversely, when the second hand 15 is in any of the processing chambers 22, the first is located. The hand 14 is located in the transport chamber 21. Therefore, when the first hand 14 is moved to one of the processing chambers 22 based on the teaching data, and when the arms 12 and 13 are folded from that state and the first hand 14 is returned to the transport chamber 22, the first origin is obtained. Using the position and the corresponding origin offset, similarly, when moving the second hand 15 to one of the processing chambers 22 based on the teaching data, and from that state, the arms 12 and 13 are folded and the second hand 15 is folded. Is returned to the transport chamber 22 by using the second origin position and the corresponding origin offset. When the robot is replaced, for example, when the motor 18, the arms 12, 13, and the hands 14 and 15 are replaced, the value of the origin offset is generally different before and after the replacement. Therefore, in order to use the same teaching data before and after the robot exchange without re-teaching, it is necessary to correct the teaching data based on the change in the origin offset due to the robot exchange.

When finding the origin offset after replacing the robot, it is necessary to move the robot to the origin position. At this time, since the origin offset after the robot is replaced is not yet known, the robot cannot be moved to the origin position by an origin return command or the like for the robot. Therefore, the robot may be moved to the origin position by using the teaching pendant while visually observing the robot. In order to move the robot to the origin position more accurately, for example, as described in Patent Document 2, pin holes for restricting the posture of the robot to the posture at the origin position are provided in the arms 12, 13 and the hand 14. The robot may be fixed at the origin position by providing it in the mounting portion 16 or the like and inserting a jig pin into the pin hole. When a jig pin is used, an origin sensor is provided on one of two structures (arms 12, 13 and hands 14, 15) that share a joint axis separately from the encoder 19, and a groove that can be detected by the origin sensor is provided on the other. Rough adjustment is made based on the output of the origin sensor, and then fine adjustment is made to slowly move the robot to the position where the jig pin fits in the pin hole, and the robot is mechanically moved to the origin position. Can be done. The jig pin and the pin hole have a function of restricting the position between the structures (here, the base 11, the arms 12, 13 and the hands 14, 15) included in the robot. In the present 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.

By the way, at the origin position, the robot arms 12 and 13 and the first hand 14 are folded, and the second hand 15 extends in the extension direction of the second arm 13, and the arm and the hand are like a transport robot. In the case of a long robot, if the arms 12 and 13 are extended and the mounting portion 16 is rotated around the axis S, the hands 14 and 15 are rotated and moved by simply compensating for the change in the origin offset. In addition, it is not always possible to move exactly to the desired position. This is because the installation position and orientation of the robot may shift due to the replacement of the robot, and the mounting states of the hands 14 and 15 may change. Therefore, in the present embodiment, the arms 12, 13 and the hands 14, 15 of the robot are extended and moved to a predetermined position based on the teaching data before and after the robot is replaced. Then, in an external coordinate system (for example, a coordinate system defined in the processing chamber 22) that is separate from the coordinate system of the robot itself, coordinates indicating the position and posture of the robot are obtained. These coordinates are called predetermined position coordinates. Since the predetermined position coordinates are for compensating for the deviation that cannot be compensated by the origin offset, the positions are as far as possible from the base 11 of the robot with the arms 12, 13 and the hands 14, 15 extended as much as possible. It is preferable to measure with. Therefore, in the present embodiment, the predetermined position coordinates are measured by 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 processing chamber 22 on the side far from the transport chamber 21. Since it is necessary to consider the mounting error of the hands 14 and 15 with respect to the mounting portion 16, predetermined position coordinates are obtained for each of the first hand 14 and the second hand 15. A camera 23 and a reference marker 24 may be provided in a single processing chamber 22 to sequentially obtain predetermined position coordinates of the first hand 14 and the second hand 15, or, for example, they face each other with the transport chamber 21 interposed therebetween. A camera 23 and a reference marker 24 are provided in each of the two processing chambers 22 at positions, one of the processing chambers 22 obtains predetermined position coordinates for the first hand 14, and the other processing chamber obtains predetermined position coordinates for the second hand 15. The position coordinates may be obtained.

In the measurement of the predetermined position coordinates with respect to the hand 14, the measuring jig is placed at the correct position of the hand 14 as the work 31, and the hand 14 is placed in the processing chamber 22 based on the teaching data while the measuring jig is still mounted. The image is taken by the camera 24 so that the measuring jig is reflected in the image. Similarly, in the measurement of the predetermined position coordinates with respect to the hand 15, the jig for measurement is placed at 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 moved to take a picture. .. In the present embodiment, for example, a square-shaped jig is used as the measuring jig, the edge of the jig is extracted from the image taken by the camera 24, and the image of the reference marker 24 and the image of the edge of the jig are taken. The coordinates of the edge of the jig are obtained from the positional relationship with the robot, and this is used as the predetermined position coordinates of the robot. At this time, the coordinates of the position of the apex of the measuring jig which is a quadrangle may be obtained, or in addition to the coordinates of the apex, the orientations of the two sides connected to the apex are acquired as an indicator of the posture of the robot. May be good. 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 reason why the robot is moved based on the teaching data in the measurement of the predetermined position coordinates is to eliminate the influence of the backlash.

In the position information restoration method of the present embodiment, the amount of change in the origin offset before and after the robot exchange is defined as the amount of origin deviation, and the amount of change in the predetermined position coordinates before and after the robot exchange is defined as the amount of coordinate deviation. The methods described in Patent Documents 1 and 3 are, after all, a method of measuring a value corresponding to the sum of the origin deviation amount and the coordinate deviation amount and using it for correcting the teaching data, and are described in Patent Document 2. The method relates to the measurement of the amount of origin deviation. On the other hand, in the present embodiment, when the teaching data is reused after the robot is replaced, the teaching data is corrected by using both the origin deviation amount and the coordinate deviation amount, but the origin deviation amount is used for each hand. The amount of coordinate deviation is managed separately. In the storage unit 44, the origin offset before and after the robot exchange and the origin deviation amount for each hand calculated from the origin offset are stored in the origin offset storage unit 52, and the predetermined position coordinates before and after the robot exchange and the coordinate deviation amount for each hand calculated from the predetermined position coordinates are stored. Is stored in the predetermined position coordinate storage unit 53.

In the present embodiment, the origin deviation amount and the coordinate deviation amount are managed separately. When both are managed as one, even if there is an abnormality in these deviation amounts, the abnormality can be found. It becomes difficult, it becomes difficult to verify the validity of the detected deviation amount, and it becomes difficult to determine which deviation amount has an abnormality, and in the end, it takes a lot of labor to restart the robot. Because there is. The origin deviation amount is the deviation amount related to the internal coordinates of the robot itself, which is irrelevant to the external environment, and indicates how the relationship between the structures constituting the robot has changed due to the robot exchange. On the other hand, the amount of coordinate deviation may be affected by the difference in length between the arms 12, 13 and hands 14, 15 before and after replacement, but in the case of a large horizontal articulated robot for transportation, it is basically. Shows the deviation due to the difference in the installation position and orientation of the robot. Therefore, there is no inconvenience in managing the origin deviation amount and the coordinate deviation amount separately. Furthermore, even if data is lost in the process of acquiring the origin deviation amount and the coordinate deviation amount, for example, due to a voltage abnormality, if the calculation of the origin deviation amount is completed, it is necessary to start over from the beginning. However, it is possible to restart from the calculation of the coordinate deviation amount by using the already calculated origin deviation amount as it is.

Here, the amount of coordinate deviation will be examined. The amount of coordinate deviation basically has a component caused by the deviation of the robot installation position on the plane on which the robot is installed and the deviation of the direction of the robot. The goal of this embodiment is to reuse the teaching data without re-teaching after replacing the robot, and when the teaching data is reused, the error in the positions of the hands 14 and 15 in each processing chamber 22 is set to a predetermined value. It is to be within. Focusing on the first hand 14, for example, a deviation of 1 mm at the robot installation position is only a deviation of 1 mm at the position of the first hand 14, but the lengths of the robot arms 12, 13 and the first hand 14 Considering a large transfer robot having a sum of 3 m, a deviation of 0.1 ° in the direction of the robot corresponds to a deviation of about 5 mm at the position of the extended first hand 14. It is easy to set the installation position error (deviation of the center position of the robot) to 1 mm or less, but it is difficult to set the orientation error to 0.1 ° or less. Therefore, it can be considered that the coordinate deviation amount corrects the deviation of the direction of the robot after the robot is replaced, and if so, the coordinate deviation amount is obtained by a simple calculation using one reference marker 24. Will be able to. Then, by using the accurately obtained origin deviation amount and the coordinate deviation amount calculated using one reference marker 24, the teaching data used before the robot exchange is corrected, and the teaching data is obtained. Can be reused.

In the present embodiment, the amount of coordinate deviation is determined for each hand using the camera 23 and the reference marker 24 provided in any of the processing chambers 22, but the processing chamber 22 provided with the camera 23 and the reference marker 24 determines the amount of coordinate deviation. It is preferable that the processing chamber 22 is actually used by the hand when moving the robot based on the teaching data. Further, when the coordinate deviation amount is obtained from the predetermined position coordinates for each hand, the teaching data using the hand is corrected by using the origin deviation amount and the coordinate deviation amount, and after returning to the origin position once, the above predetermined position is performed again. 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 deviation related to the hand is determined, and if not, the predetermined position coordinates are obtained this time. By repeating updating the amount of coordinate deviation according to the predetermined position coordinates, the correction accuracy when reusing the teaching data can be improved.

FIG. 4 shows an example of processing by the position information restoration method of the present embodiment. In FIG. 4, steps 101 to 103 show the processing in the preparatory stage before the robot exchange, and steps 105 to 116 show the processing performed after the robot exchange. In the process performed before the robot exchange, first, in step 101, the origin offset for each hand before the robot exchange is stored in the origin offset storage unit 52. When a robot is installed, the origin offset of each hand should be obtained by aligning the origin of the robot, so that value may be used. Next, in step 102, a jig for measurement is attached to the first hand 14 as the work 31, and the position is set to the above-mentioned predetermined position based on the teaching data A which is the teaching data when the first hand 14 accesses the processing chamber 22. The robot is moved, the edge of the jig is detected using the camera 23 and the reference marker 24, and the predetermined position coordinates are obtained. The predetermined position coordinates obtained here are set as the position P1 for the first hand 14, and are stored in the predetermined position coordinate storage unit 53. Similarly, in step 103, a jig for measurement is attached to the second hand 15 as the work 31, and at the predetermined position described above based on the teaching data B which is the teaching data when the second hand 15 accesses the processing chamber 22. The robot is moved, the edge of the jig is detected using the camera 23 and the reference marker 24, and the predetermined position coordinates are obtained. The predetermined position coordinates obtained here are set as the position P2 for the second hand 15, and are stored in the predetermined position coordinate storage unit 53.

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

After the robot exchange is completed, in step 105, the robot is mechanically moved to the first origin position corresponding to the first hand 14 and the second origin position corresponding to the second hand 15, and after the robot exchange in each case. The origin offset of the above is obtained and stored in the origin offset storage unit 52. In step 106, the difference in origin offset before and after robot replacement for each hand stored in the origin offset storage unit 52 is obtained as the origin deviation amounts D1 and D2 and stored in the origin offset storage unit 52. The difference in the origin offset with respect to the first hand 14 is the origin deviation amount D1, and the difference in the origin offset with respect to the second hand 15 is the origin deviation amount D2. Subsequently, in step 107, the same measurement jig as that used in step 102 is mounted on the first hand 14, and the teaching data A corrected in consideration of the origin deviation amount D1, that is, based on the origin deviation amount D1. To move the robot to a predetermined position using. Then, the predetermined position coordinates are obtained in the same manner as described above, 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 deviation amount E1 with respect to 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.

Next, in step 109, the robot is moved to the first origin position by inputting a command to the robot controller 40, and then the teaching data A corrected based on the origin deviation amount D1 and the coordinate deviation amount E1 with respect to the first hand 14 is used. The robot is moved from the first origin position to a predetermined position, the predetermined position coordinates are obtained in the same manner as described above, and the predetermined position coordinates at this time are stored in the predetermined position coordinate storage unit 53 as the position R1. Then, in step 110, it is determined whether or not the difference between the position P1 obtained before the robot replacement and the position R1 obtained this time exceeds the allowable value. When the allowable value is exceeded, the coordinate deviation amount E1 with respect to the first hand 14 is not accurately obtained. Therefore, in step 111, the coordinate deviation amount E1 is recalculated based on the difference between the position P1 and the position R1. Then, it is stored in the predetermined position coordinate storage unit 53. In the recalculation of the coordinate deviation amount E1, the coordinate deviation amount E1 before the recalculation caused a deviation exceeding the allowable value between the position P1 and the position R1, so that the coordinate deviation amount is eliminated so as to eliminate this deviation. An operation is performed to obtain a value that corrects E1. After the execution of step 111, the process returns to step 109, and the processes of steps 109 to 111 are repeated until the difference between the position P1 and the position R1 is within the allowable value. If the difference between the position P1 and the position R1 is within the allowable value in step 110, the coordinate deviation amount E1 for the first hand 14 is determined, and the process proceeds to step 112.

After the coordinate deviation amount E1 for the first hand 14 is determined, the coordinate deviation amount E2 for the second hand 15 is subsequently determined by the same procedure. In step 112, the same measurement jig as that used in step 103 is mounted on the second hand 15, and the robot is moved to a predetermined position using the teaching data B corrected based on the origin deviation amount D2 to determine the predetermined position. The 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 Q2. In step 113, the coordinate deviation amount E2 with respect to the second hand 15 is obtained from the difference between the position P2 and the position Q2 and stored in the predetermined position coordinate storage unit 53. Next, in step 114, the robot is moved to the second origin position by command input, and then the robot is moved using the teaching data B corrected based on the origin deviation amount D2 and the coordinate deviation amount E2 with respect to the second hand 15. 2 The predetermined position coordinates are obtained by moving from the origin position to a predetermined position, and the predetermined position coordinates at this time are stored in the predetermined position coordinate storage unit 53 as the position R2. Then, in step 115, it is determined whether or not the difference between the position P2 obtained before the robot replacement and the position R2 obtained this time exceeds the allowable value. When the allowable value is exceeded, in step 116, an operation is performed to obtain a value for correcting the coordinate deviation amount E2 so as to eliminate this difference based on the difference between the position P2 and the position R2. After the execution of step 116, the process returns to step 114, and the processes of steps 114 to 116 are repeated until the difference between the position P2 and the position R2 is within the allowable value. If the difference between the position P2 and the position R2 is within the allowable value in step 115, the coordinate deviation amount E2 for the second hand 15 is also determined, and the process of restoring the position information is completed.

After the origin deviation amount and the coordinate deviation amount are determined for each hand as described above and stored in the origin offset storage unit 52 and the predetermined position coordinate storage unit 53, respectively, the teaching data used before the robot replacement is used. By making corrections based on the amount of origin deviation and the amount of coordinate deviation, the teaching data can be continued to be used even after the robot is replaced. In the correction of the teaching data, the origin deviation amount and the coordinate deviation amount corresponding to the hand to be used are used depending on whether the teaching data uses the first hand 14 or the second hand 15 to access the processing chamber 22. And correct the teaching data. Therefore, it is necessary to determine which hand is being used. Hereinafter, the method of detecting the hand being used will be described.

The transport robot as shown in the present embodiment is used to move the work 31 in and out of the processing chamber 22, but the hands 14 and 15 and the work 31 held by the hands 14 and 15 collide with the wall surface of the transport chamber 21. To avoid this, the rotation of the hands 14 and 15 around the axis S is performed when the axis S is in the center of the transport chamber 21, in other words, when the robot is at or near the origin position. After the directions of the hands 14 and 15 are determined by the rotation around the axis S, the robot moves so that the hands 14 and 15 move in parallel with the coordinate system of the transport chamber 21, and particularly to the processing chamber 22. On the other hand, when the work 31 is taken in and out, the hands 14 and 15 move linearly with respect to the processing chamber 22 from the front direction of the processing chamber 22. Therefore, in the present embodiment, in the robot, apart from the XY coordinate system which is the orthogonal coordinate system fixed to the base 11, the transformed coordinate system (XY') whose Y'axis is the extending direction of the hands 14 and 15. Coordinate system) is defined. FIG. 5 is a diagram for explaining the transformed coordinate system, and shows the relationship between the transformed coordinate system and the Cartesian coordinate system (XY coordinate system) fixed to the base 11. In the figure, the base 11 is not shown, and the arms 12, 13 and the hands 14, 15 are shown by thick lines. The point C in the figure is a position where the mounting portion 16 is connected to the axis S, is a rotation center when the hands 14 and 15 rotate, and is a control target when the robot arms 12 and 13 are moved. It is a point that becomes a point. The origin O of the XY coordinate system is at the position of the axis A (see FIG. 1), which is the joint axis between the base 11 and the first arm 12. Since the base 11 is fixed to the transport chamber 21, it can be said that the XY coordinate system is also fixed to the transport chamber 21 except for contributions such as an error in the installation position of the robot. On the other hand, the transformed coordinate system is a Cartesian coordinate system in which the origin coincides with the origin O of the XY coordinate system and the direction of the Y'axis coincides with the extending direction of one of the hands 14 and 15. There are two ways to determine the conversion coordinate system depending on whether the extending direction of the first hand 14 is the Y'axis direction or the extending direction of the second hand 15 is the Y'direction. FIG. 5A shows a case where the extending direction of the first hand 14 is the Y'axis direction, and FIG. 5B shows a case where the extending direction of the second hand 15 is the Y'axis direction.

In the present embodiment, after the hands 14 and 15 are rotated around the axis S in the robot at or near the origin position, the hands 14 and 15 only move in parallel with the coordinate system of the transport chamber 21. .. Therefore, in the teaching data, for the movement from the origin position toward the processing chamber 22 and the movement returning from the processing chamber 22 to the origin position, the movement command for this point is converted into the conversion coordinate system (X'Y' coordinate system) with the point C as the control target point. ). By using the transformed coordinate system, the movement when the hands 14 and 15 are moved into the processing chamber 22 or taken out of the processing chamber 22 is represented by addition or subtraction of the coordinates of the point C with respect to the Y'coordinate value. When the extending direction of the first hand 14 is defined as the Y'axis direction as shown in FIG. 5A, the moving direction of the first hand 14 to any of the processing chambers 22 is the Y'axis positive direction. The Y'coordinate value of the coordinate of the point C is positive while the first hand 14 moves from the origin position to the processing chamber 22 and returns from the processing chamber 22 to the origin position. Further, in the case of FIG. 5A, the moving direction of the second hand 15 to any processing chamber 22 is the negative direction on the Y'axis, and the second hand 15 moves from the origin position to any processing chamber 22. The Y'coordinate value of the coordinate of the point C is negative during the period of time and while returning from the processing chamber 22 to the origin position. Similarly, when the extending direction of the second hand 15 is set as the Y'axis direction as shown in FIG. 5 (b), the coordinates of the point C in the movement of accessing any of the processing chambers 22 by the first hand 14 The Y'coordinate value of is negative, and the Y'coordinate value of the coordinate of the point C becomes positive in the movement of accessing any of the processing chambers 22 by the second hand 15. Therefore, by determining whether the Y'coordinate value of the coordinate of the point C to be controlled in the teaching data is positive or negative, which of the hands 14 and 15 is used without providing a sensor or the like on the robot. It is possible to determine whether or not the processing room 22 is being accessed by the hand of.

[Effect of embodiment]
According to the embodiment described above, in the robot provided with a plurality of hands, the origin deviation amount based on the origin offset and the coordinate deviation amount based on the predetermined position coordinates are separately calculated, stored, and managed for each hand. This makes it possible to reliably detect an abnormal value in each deviation amount, and by correcting the teaching data using the origin deviation amount and the coordinate deviation amount for each hand, without re-teaching, and , The teaching data used before the robot exchange can be used even after the robot exchange without the calibration result for each hand affecting other hands. Further, the robot controller 40 shown in FIG. 2 is designed so that the origin offset and the predetermined position coordinates can be managed separately, but the hardware configuration is not different from that of a general robot controller. The method of restoring the position information of the form can be realized by 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 by using the two reference markers 24 provided in the processing chamber 22, the predetermined position coordinates are obtained. It will be possible to separately acquire the deviation of the installation position and the deviation of the orientation, and it will be possible to accurately obtain the amount of coordinate deviation in a short time. FIG. 6 shows an example in which the camera 23 is arranged corresponding to each of the two reference markers 24, assuming that the processing chamber 22 is provided with the two reference markers 24. When the predetermined position coordinates are obtained using the two reference markers 24, the deviation of the installation position and the deviation of the orientation can be obtained separately. Therefore, the amount of the origin deviation is obtained by performing only rough adjustment by the origin sensor. Even if the value is used, the robot can be moved with sufficient accuracy when the teaching data is reused. If a camera 23 having a sufficiently wide field of view can be used, the two reference markers 24 can be photographed by using a single camera 23 so that the measuring jig is reflected, and from the photographed image, the two reference markers 24 can be photographed. It is possible to separately obtain the deviation of the installation position and the deviation of the orientation. If a jig for measuring a quadrangle is used, when two reference markers 24 are used, the reference markers 24 may be arranged corresponding to each of the vertices on both sides of one diagonal line of the jig. By doing so, the distance between the two positions for detecting the edge of the jig can be lengthened, so that the deviation of the orientation can be detected with high accuracy.

The robot shown in FIG. 1 is a horizontal articulated robot in which the arms 12, 13 and the hand 14 are connected to the base 11 in this order, but the robot to which the position information restoration method of the present invention can be applied is to this. Not limited. For example, a base, a base-side link connected to the base, an arm-side link connected to the tip of the base-side link, an arm connected to the tip of the arm-side link, and a hand connected to the tip of the arm. The present invention is also applicable to a horizontal articulated robot provided on the base, which is provided with a mechanism for raising and lowering the base side link, and whose movement of the tip of the arm side link is restricted by the link mechanism. Furthermore, the present invention can be applied to vertical articulated robots and the like.

11 ... base; 12,13 ... arm; 14,15 ... hand; 16 ... mounting part; 18 ... motor; 19 ... encoder; 21 ... transport chamber; 22 ... processing chamber; 23 ... camera; 24 ... reference marker; 31 ... Work; 40 ... Robot controller; 41 ... Bus; 42 ... Servo circuit; 43 ... CPU; 44 ... Storage unit; 51 ... Teaching data storage unit; 52 ... Origin offset storage unit; 53 ... Predetermined position coordinate storage unit; 60 ... Teaching pendant.

Claims (8)

A method for restoring position information of a robot that is used in a processing apparatus having a plurality of processing chambers and that supports an object and conveys the object between the plurality of processing chambers based on teaching data.
The robot includes a base installed in the processing device, a plurality of hands supporting the object, and at least one arm interposed between the base and the plurality of hands.
The plurality of hands are attached to the arm, which is the end when viewed from the base, via an attachment portion.
The replacement of a part of the robot, the reassembly of a part or all of the robot, or the relocation of the robot is regarded as the robot replacement, and the origin offset for each hand of the robot and the arm are performed before the robot replacement is executed. And the step of memorizing the predetermined position coordinates for each hand indicating the position and posture of the robot when the hand is extended and moved to the predetermined position.
After the robot exchange, the origin offset of the robot is acquired for each hand, and the origin deviation amount, which is the difference between the origin offset before the robot exchange and the origin offset after the robot exchange, is obtained for each hand. The process of memorizing and
After the robot exchange, the arm is extended and the hand is moved to the predetermined position to acquire the predetermined position coordinates for each hand, and the predetermined position coordinates before the robot exchange for each hand and the robot exchange are performed. Later, a step of calculating and storing the amount of coordinate deviation for each hand based on the difference from the predetermined position coordinates, and
Have,
A position information restoration method for separately managing the origin deviation amount and the coordinate deviation amount for each hand. The processing device is provided with one reference marker, and at least a part of the object mounted on the hand and the reference marker are imaged by a visual sensor to acquire the position of the object, thereby being separate from the robot. The position information restoration method according to claim 1, wherein the predetermined position coordinates in the coordinate system are acquired. The processing device is provided with two reference markers, and at least a part of the object mounted on the hand and the reference marker are imaged by a visual sensor to acquire the position of the object, thereby being separate from the robot. The position information restoration method according to claim 1, wherein the predetermined position coordinates in the coordinate system are acquired. The position information restoration method according to claim 2 or 3 , wherein the reference marker is provided in any one of the plurality of processing chambers. Claims 1 to 4 detect a hand used in the teaching data among the plurality of hands, and correct the teaching data by using the origin deviation amount and the coordinate deviation amount with respect to the detected hand. The position information restoration method according to any one of the above items. Until the deviation of the predetermined position coordinates before and after the robot exchange is within the allowable range, the teaching data is corrected by using the origin deviation amount and the coordinate deviation amount, and the teaching data is based on the corrected teaching data. The position information restoration method according to claim 5, wherein the robot is repeatedly moved from the origin position to the predetermined position and the coordinate deviation amount is recalculated. The position information restoration method according to claim 5 or 6, wherein the number of the hands is two, and the two hands are attached to the attachment portion so as to form a positional relationship of 180 ° with each other. In the teaching data, a conversion coordinate system is used in which the direction in which one of the two hands extends is the positive direction.
When the moving direction of the hand to the processing chamber in the teaching data coincides with the positive direction of the transformed coordinate system, it is detected that one of the hands is the used hand.
The position information restoration according to claim 7, wherein when the moving direction of the hand to the processing chamber in the teaching data coincides with the negative direction of the transformed coordinate system, the other hand is detected as the used hand. Method.

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