JP2019141918A - Positional information restoration method of robot - Google Patents

Abstract

To provide a positional information restoration method in which reteaching is not required in replacing equipment constituting a robot and replacing a robot, either of reassembling and transferring the robot, and solution of a problem and verification of validity in data can be easily performed.SOLUTION: In a positional information restoration method, a zero offset of a robot and a predetermined-position coordinate indicating a position and a posture of the robot in an external coordinate system at the time when the robot is moved to the predetermined position by extending a hand of the robot are acquired before and after replacing the robot. A difference of the zero offset before and after replacing the robot is defined as a first deviation amount and a deviation amount based on a difference of the predetermined position coordinate is defined as a second deviation amount, and the first deviation amount and the second deviation amount are memorized and managed individually.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a position information restoration method that makes it possible to use conventional teaching data in a robot when exchanging equipment in the robot, reassembling or moving the robot.

  In a robot that operates based on teaching (teaching) data, equipment such as a motor and an arm constituting the robot may be replaced, and the robot itself may be reassembled or moved as necessary. When equipment is exchanged, reassembled, moved, etc., the amount of error related to assembly and installation of the robot changes, so it is necessary to re-teach the robot before performing the work again with the robot. However, since teaching robots requires a lot of time and labor, it is desired that previous teaching data can be used even when equipment is replaced, robots are reassembled or moved. Patent Document 1 relates to a robot that performs processing on a work held by a holding device, and before and after the transfer of the robot, three positions of the work held by the holding device or the holding device are attached to the robot arm. The teaching data is corrected 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 transfer of the robot.

  In the robot, the position (especially the rotational position) of each axis is obtained by a sensor (for example, an encoder). However, when the motor, reducer, or arm is replaced, the reference position used to determine the position of each axis is It will shift. This is also the cause of the fact that the previous teaching data cannot be used after replacement of the device. However, Patent Document 2 provides a pin hole in each of a pair of structures (such as an arm) constituting the joint axis of the robot, A method of defining a reference position by inserting a pin penetrating each pin hole, or a proximity sensor corresponding to a V-shaped groove provided in one structure constituting a joint shaft and a V-shaped groove provided in the other structure And a method of specifying a reference position by a signal from a proximity sensor is disclosed.

  When the device is replaced, the robot itself is reassembled or moved, calibration is performed on the robot in order to cope with changes over time. When calibration is performed, the mechanism parameters used to describe the robot kinematically change, and the teaching data used before the calibration cannot be used as they are. Patent Document 3 discloses that teaching data is corrected and used based on a mechanism parameter before calibration and a mechanism parameter after calibration.

  By the way, horizontal articulated robots among various robots are used for transporting, for example, semiconductor wafers and glass substrates. Patent Documents 4 and 5 show examples of a horizontal articulated robot for transfer using a semiconductor wafer or a glass substrate as a transfer target. With the increase in the size of the objects to be transported by the horizontal articulated robot and the complexity of the processes performed on the objects to be transported, the horizontal articulated robot itself has also increased in size and the transport distance of the objects to be transported has become longer. . As horizontal articulated robots become larger, it is necessary to disassemble and transport the robot once and reassemble it at the installation site after the robot is completed and adjusted in order to ship the robot and install it to the customer. ing.

Japanese Patent No. 3733364 Japanese Patent No. 4819957 Japanese Patent Laid-Open No. 2017-213668 JP-A-2015-139854 Japanese Patent No. 5199117

  Patent Documents 1-3 make it possible to use previous teaching data without re-teaching even when the robot is replaced, the robot itself is reassembled or moved, and the robot is recalibrated. A method is disclosed. In each of the methods of Patent Literatures 1-3, a set of correction data (if Patent Literature 1 is used, data relating to a positional shift relating to a specific holding device before and after the relocation, and if Patent Literature 2 is used, data for correcting a reference position is provided. Patent Document 3 relies on data relating to deviations in mechanism parameters before and after calibration. However, when the robot is enlarged and its movement range is increased as in the case of a horizontal articulated robot for transfer, the teaching data can be sufficiently corrected by the method of Patent Documents 1-3. As a result, re-teaching may be forced. In addition, if there is a problem with the correction data used to correct the teaching data, it is difficult to deal with the cause of the problem and it is difficult to verify the validity of the correction data. Takes a lot of effort.

  It is an object of the present invention to eliminate re-teaching when exchanging equipment constituting a robot, reassembling or moving the robot in a robot such as a large horizontal articulated robot for conveyance, It is an object of the present invention to provide a position information restoration method capable of easily verifying validity.

  The position information restoring method of the present invention is used in a processing apparatus having a plurality of processing chambers, and is a position information restoring method for a robot that supports an object and conveys it between a plurality of processing chambers based on teaching data. The robot includes a base installed in the processing apparatus, a hand that supports an object, and at least one arm interposed between the base and the hand. As a robot replacement, a part or all of the robot is reassembled, or the robot is relocated, and the robot's origin offset and the robot's position and posture when the hand is extended and moved to the specified position before the robot replacement is performed. After the process of memorizing the position coordinates and the robot exchange, the origin offset of the robot is obtained and the origin offset before the robot exchange and the original after the robot exchange After storing the first deviation amount, which is the difference from the offset, and exchanging the robot, extend the hand and move the robot to the predetermined position to obtain the predetermined position coordinates, and replace the robot with the predetermined position coordinates before the robot replacement. And calculating and storing a second deviation amount based on a difference from the predetermined position coordinate after that, and managing the first deviation amount and the second deviation amount separately.

  In the present invention, the correction amount used for correcting the teaching data is divided into a first deviation amount based on the origin offset and a second deviation amount based on the predetermined position coordinates, and these deviation amounts are managed separately. When there is an abnormality in the amount of deviation, it is possible to easily determine that there is an abnormality and which deviation amount the abnormality is in. Even if data loss or the like occurs in the process of calculating the deviation amount, if the calculation of the first deviation amount is completed, the first deviation amount can be used as it is to calculate the second deviation amount. The time for calculating the correction amount can be shortened.

  In the position information restoration method of the present invention, the processing apparatus includes 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 It is preferable to acquire predetermined position coordinates in a coordinate system different from the coordinate system, for example, the coordinate system of the processing apparatus. The displacement that occurs in the predetermined position coordinates when moving to a predetermined position after exchanging the robot is mainly due to the positional deviation in the plane where the robot is installed (the deviation in the XY coordinates with the robot installation plane as the XY plane) and the orientation of the robot However, since the influence of the direction deviation is larger than the position deviation in a large robot, if the second deviation amount is calculated by paying attention to the direction deviation, 1 The use of only one reference marker is sufficient, and the calculation for calculating the second deviation amount can be simplified.

  In the present invention, after the robot replacement, the robot is brought to the origin position by rough adjustment by the origin sensor provided in the robot and fine adjustment by the fitting means for regulating the position between the structures included in the robot. It can be moved to get the origin offset. By moving the robot to the origin position in such a procedure when obtaining the origin offset, it becomes possible to accurately align the origin position by mechanical means in the robot. Thereby, even when only one reference marker is used, when the teaching data is corrected based on the first deviation amount and the second deviation amount, the robot accurately moves to a desired position based on the teaching data. become able to.

  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 imaged by a visual sensor to obtain the position of the object. You may make it acquire the predetermined position coordinate in a system, for example, the coordinate system of a processing apparatus. When two reference markers are provided, the positional deviation and the angular deviation included in the second deviation amount can be separated, so even if there is some error in the origin offset, the first deviation amount and the second deviation amount are provided. The teaching data corrected based on the amount enables the robot to be accurately moved to a desired position. When two reference markers are provided, the shape of the object is a quadrilateral shape, and two reference markers are provided corresponding to the positions that are both ends of one diagonal line of the object when the robot is at a predetermined position. It is preferable to provide it. By providing the reference markers corresponding to both ends of the diagonal line, the distance between the reference markers is increased, and the deviation of the orientation in the robot can be accurately detected.

  In the present invention, it is preferable to provide a reference marker in any one of the plurality of processing chambers. In the processing apparatus, by using the reference marker provided in the processing chamber that is actually used, the teaching data can be corrected for the deviation in the processing chamber that is actually used. When the reference marker is provided in the processing chamber as described above, the predetermined position is preferably a position when the hand is farthest from the base in the processing chamber. Since the robot arm and hand are extended and the position where the hand is farthest from the base in the processing chamber is set to a predetermined position, the deviation of the robot orientation can be detected as a large value, so the teaching data can be corrected with high accuracy. You can do it.

  In the present invention, it is preferable to move the robot to a predetermined position based on teaching data actually used in the robot. By moving based on actually used teaching data, the amount of deviation is calculated in consideration of the moving direction of the robot, and the influence of backlash can be reduced. At this time, the teaching data is corrected using the first deviation amount and the second 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 based on the corrected teaching data. It is possible to repeat the recalculation of the second shift amount by moving from the origin position to a predetermined position. Such repeated calculation can improve the accuracy of correcting the teaching data.

  According to the present invention, re-teaching is not required for replacement of equipment constituting the robot, re-assembly or relocation of the robot, and it is possible to easily solve the defect in the data and verify the validity. .

It 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 the robot in an 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, (b) is a figure which shows typically the cross section of a processing chamber. It is a flowchart which shows operation | movement of the positional information restoration method based on this invention. 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 describing the position information restoration method according to 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 a position information restoration method according to the present invention is applied. FIGS. 1A and 1B are a plan view and a front view showing a robot in a state where arms and hands are extended. The robot shown in FIG. 1 is the same as the horizontal articulated robot for transfer described in Patent Document 4, and includes a base 11, a first arm 12 attached to the base 11, and a first arm 12. A second arm 13 attached to the tip of the arm 12 and a hand 14 attached to the tip of the second arm 13 are provided. The hand 14 holds a semiconductor wafer, a glass substrate, or the like, which is an object to be transferred, and is formed in a fork shape. The first arm 12 can rotate about the axis A relative to the base 11, the second arm 13 can rotate about the axis B relative to the first arm 12, and the second arm 13 can rotate relative to the second arm 13. The hand 14 can rotate around the axis C. In order to enable rotation about axes A to C, which are joint axes of the robot, the robot is provided with a motor for each axis. Further, the robot is provided with a mechanism for raising and lowering the first arm 12 in the Z direction shown in the figure on the base 11, and this raising and lowering mechanism is also driven by a raising and lowering motor. The axes A to C are all parallel to the Z direction. Each of the base 11, the arms 12, 13 and the hand 14 is a structure included in the robot.

  In the robot shown in FIG. 1, an origin position serving as a reference for the operation of the robot is determined. At the origin position, the robot has a predetermined folded posture of the arm and the hand. FIG. 1C shows the posture of the robot at the origin position. The second arm 13 and the hand 14 are folded so that the second arm 13 and the hand 14 overlap with the first arm 12.

  A robot controller is provided to control the robot shown in FIG. FIG. 2 shows an electrical circuit configuration of the robot and the robot controller 40. As described above, the robot is provided with four motors 15 for the axes A to C and the lifting mechanism, and these motors 15 have an encoder 16 for measuring the rotation angle of the motor 15. Each is attached.

  The robot controller 40 performs a bus 41 used for transmitting various signals and data, a servo circuit 42 provided for each motor 15 to drive the motor 15, and calculations necessary for the operation and control of the robot. A CPU (central processing unit) 43 that outputs a command to each servo circuit 42 and a storage unit 44 that stores data necessary for calculation and control by the CPU 43 are provided. The storage unit 44 includes a teaching data storage unit 51 that stores teaching data as a storage area or file, an origin offset storage unit 52 that stores an origin offset, and a predetermined position coordinate storage unit 53 that stores predetermined position coordinates. Is set. The origin offset and the 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 16 is supplied to the servo circuit 41 that drives the corresponding motor 15 and is also sent to the CPU 43 via the bus 41. The robot controller 40 is connected to a camera 23 that is a visual sensor and a teaching pendant 60 used for teaching the robot, and these are connected to a bus 41 via an interface circuit (not shown).

  Next, the usage form of the robot described here will be described with reference to FIG. Here, a robot is used in a processing apparatus used for manufacturing a liquid crystal display or an organic EL (electroluminescence) display by performing a film forming process or an etching process on the work 31 which is a substantially rectangular glass substrate. Shall be. As shown in FIG. 3A, the processing apparatus includes a transfer chamber (transfer chamber) 21 and a plurality of process chambers (process chambers) 22 arranged so as to surround the transfer chamber 21. There are processing chambers 22 provided for carrying work 31 in and out of the manufacturing system itself, and processing chambers 22 for performing film formation, etching, and other processing on the work 31. The robot is provided in the transfer chamber 11 by installing the base 11 in the transfer chamber 21, and transfers the workpiece 31 between the processing chambers 22 through the transfer chamber 21. Therefore, the robot is provided substantially in the center of the transfer chamber 21, and the arms 12 and 13 are extended so that the hand 14 enters the processing chamber 22 when the workpiece 31 is transferred.

  Among the plurality of processing chambers 22, for example, a reference marker 24 is attached to the ceiling surface of the processing chamber 22 used for loading / unloading the work 31 with the outside of the manufacturing system, as shown in FIG. A camera 23 is provided on the floor of the processing chamber 22 so as to photograph the reference marker 24. The camera 23 is also depicted in FIG. The camera 23 and the reference marker 24 are used to determine whether or not the work 31 placed on the robot hand 14 is placed at the correct position on the hand 14. 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 reference marker 24 is photographed by the camera 23 so that the edge (edge) of the work 31 is reflected at that time. Thus, it is possible to know whether or not the work 31 is correctly placed on the hand 14 and how much it is displaced in which direction when it is placed out of the original position. When the placement position of the work 31 is deviated from the original position, the placement position of the work 31 can be corrected by a position correction device (not shown).

  Next, a location information restoration method in the embodiment of the present invention will be described. The position information restoration method according to the present embodiment is a method for exchanging, reassembling, or relocating equipment such as a motor or an arm that constitutes a robot 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. Hereinafter, the exchange of equipment in the robot and the reassembly and transfer of the robot itself will be collectively referred to as robot exchange.

  As described above, the origin position serves as a reference for the position and orientation when the robot is moved, and in the robot at the origin position, the rotational position of each motor 15 of the robot is considered to be zero. The rotational position of the motor 15 is measured by the encoder 16 connected to the motor 15 and output to the robot controller 40. However, the value of the rotational position output from the encoder 16 is zero even if the robot is at the origin position, depending on the assembly state of the motor 15 with respect to the arms 12, 13 and the hand 14, and the assembly state between the motor 15 and the encoder 16. It does not always become. The rotational position measured by the encoder 16 when the robot is at the origin position is called an origin offset. When moving the robot based on the teaching data, the teaching data assumes that the rotation position at the origin position is zero, and compensation is performed by the origin offset, or the rotation position at the origin position is the origin offset. The teaching data needs to be described as the indicated value. In any case, when the robot is replaced, for example, when the motor 15 or the hands 12 and 13 are replaced, the origin offset value generally differs before and after the replacement. Therefore, in order to use the same teaching data before and after the robot replacement without re-teaching, it is necessary to correct the teaching data based on the change in the origin offset due to the robot replacement.

  When obtaining 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 exchanging the robot 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 using a teaching pendant while viewing 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 attitude of the robot to the attitude 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 and inserting a jig pin into the pin hole. When using a jig pin, separately from the encoder 16, an origin sensor is provided on one of two structures (arms 12, 13 and hand 14) sharing the joint axis, and the other is a groove or protrusion that can be sensed by the origin sensor. And then make coarse adjustments based on the output of the origin sensor, and then make fine adjustments to slowly move the robot to the position where the jig pin fits into the pin hole to move the robot mechanically to the origin position . The jig pins and the pin holes function as fitting means for regulating the positions of the structures included in the robot (here, the base 11, the arms 12, 13 and the hand 14).

  By the way, the origin position is a state in which the arms 12 and 13 of the robot and the hand 14 are folded. In the case of a robot having a long arm and hand such as a transfer robot, the arm 12, When the hand 13 and the hand 14 are extended and moved, the movement to the desired position is not always possible. This is because the installation position and orientation of the robot may shift due to robot replacement. Therefore, in the present embodiment, the robot arms 12 and 13 and the hand 14 are extended and moved to predetermined positions based on the teaching data before and after the robot replacement. Then, coordinates indicating the position and orientation of the robot are obtained in an external coordinate system that is separate from the coordinate system of the robot itself (for example, a coordinate system defined in the processing chamber 22). These coordinates are called predetermined position coordinates. The predetermined position coordinates are for compensating for a deviation that cannot be compensated by the origin offset measured with the arms 12, 13 and the hand 14 folded, so that the arms 12, 13 and the hand 14 are extended as much as possible. It is preferable to perform measurement at a position as far as possible from the base 11 of the robot. Therefore, in the present embodiment, the measurement of the predetermined position coordinates is performed using the camera 23 and the reference marker 24 provided in the processing chamber 22. The camera 23 and the reference marker 24 are preferably provided on the side far from the transfer chamber 21 in the processing chamber 22.

  In the measurement of the predetermined position coordinates, a measuring jig is placed as a work 31 at the correct position of the hand 14, and the hand 14 is moved to the processing chamber 22 based on the teaching data while the measuring jig is placed. Then, the image is taken by the camera 24 so that the measurement jig is reflected. In the present embodiment, for example, a rectangular jig is used as a measurement jig, and the edge of the jig is extracted from the image photographed by the camera 24, and the image of the reference marker 24 and the edge of the jig are extracted. The coordinates of the edge of the jig are obtained from the positional relationship, and this is set as a predetermined position coordinate of the robot. At this time, the coordinates of the position of the vertex of the measurement jig that is a rectangle may be obtained, and in addition to the coordinates of the vertex, the orientation of the two sides connected to the vertex is acquired as indicating the posture of the robot. Also 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 backlash.

  In the position information restoration method according to the present embodiment, the change amount of the origin offset before and after the robot replacement is set as the first shift amount, and the change amount of the predetermined position coordinates before and after the robot replacement is set as the second shift amount. The methods described in Patent Documents 1 and 3 are ultimately methods for measuring the equivalent of the sum of the first shift amount and the second shift amount and using it for correcting the teaching data. The method performed relates to the measurement of the first deviation amount. In contrast, in the present embodiment, when the teaching data is reused after exchanging the robot, the teaching data is corrected using both the first deviation amount and the second deviation amount, but the first deviation amount and the first deviation amount are changed. The two deviation amounts are managed separately. In the storage unit 44, the origin offset before and after the robot replacement and the first deviation calculated therefrom are stored in the origin offset storage unit 52, and the predetermined position coordinates before and after the robot exchange and the second deviation calculated therefrom are the predetermined position coordinates. Stored in the storage unit 53.

  In the present embodiment, the first deviation amount and the second deviation amount are managed separately. If both are managed as one, even if these deviation amounts are abnormal, the abnormality is discovered. This is because it may be difficult to determine which shift amount is abnormal. Although there is a possibility that the difference in the arm length before and after the exchange will affect the second deviation amount, the influence of the difference in the installation position and orientation of the robot is greater than the possible difference in the arm length. The second shift amount may be considered as a shift amount related to the position of the robot with respect to the external coordinate system. On the other hand, the first deviation amount is a deviation amount relating to the coordinates of the robot itself. Therefore, there is no inconvenience in managing these shift amounts separately. Furthermore, in the process of acquiring the first deviation amount and the second deviation amount, even if data loss occurs due to, for example, voltage abnormality, if the calculation of the first deviation amount has been completed, the first deviation amount is again obtained. It is not necessary to start over from the above, and the calculation can be performed from the calculation of the second deviation amount by using the already calculated first deviation amount as it is.

  Here, the second shift amount will be examined. The second deviation amount includes a component caused by a deviation of the robot installation position on the plane where the robot is installed and a deviation of the robot orientation. The goal of this embodiment is to reuse the teaching data without re-teaching after exchanging the robot. When the teaching data is reused, the error of the position of the hand 14 in each processing chamber 22 is within a predetermined value. It is to be. A deviation of 1 mm, for example, at the position where the robot is installed is merely a deviation of 1 mm at the position of the hand 14, but a large size such that the sum of the lengths of the robot arms 12, 13 and the hand 14 is 3 m. Considering the transfer robot, 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 hand 14. Although it is easy to set the installation position error (deviation of the center position of the robot) to 1 mm or less, it is difficult to set the orientation error to 0.1 ° or less. Therefore, it can be considered that the second deviation amount corrects the deviation of the orientation of the robot after exchanging the robot. If so, the second deviation amount is obtained by simple calculation using one reference marker 24. Can be requested. Then, the teaching data used before the robot replacement is corrected by using the accurately obtained first deviation amount and the second deviation amount calculated by using one reference marker 24 to thereby obtain the teaching. Data can be reused.

  In the present embodiment, the second shift amount is determined using the camera 23 and the reference marker 24 provided in any of the processing chambers 22. However, the processing chamber 22 provided with the camera 23 and the reference marker 24 stores teaching data. It is preferable that the processing chamber 22 is actually used when the robot is moved based on the above. Further, when the second shift amount is obtained from the predetermined position coordinates, the teaching data is corrected using the first shift amount and the second shift amount, and after returning to the origin position once again, it is moved again to the predetermined position and the predetermined shift position is determined. A position coordinate is obtained. If the difference between the predetermined position coordinate obtained last time and the predetermined position coordinate obtained this time is within an allowable value, the second deviation amount is determined. Otherwise, the second deviation is determined according to the predetermined position coordinate obtained this time. By repeating the updating of the amount, it is possible to improve the correction accuracy when the teaching data is reused.

  FIG. 4 shows an example of processing by the position information restoration method of this embodiment. First, in step 101, the origin offset before the robot replacement is stored in the origin offset storage unit 52. When a robot is installed, the origin offset should normally be obtained by aligning the origin of the robot, so that value can be used. Next, in step 102, a measuring jig is attached to the robot as the work 31, the robot is moved to the predetermined position based on the teaching data, 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 coordinate obtained here is set as a position P and stored in the predetermined position coordinate storage unit 53. This is the preparatory stage before exchanging the robot. Subsequently, in step 103, the robot is exchanged, that is, equipment such as a motor and an arm in the robot is exchanged, and the robot itself is reassembled or moved.

  After completion of the robot exchange, in step 104, the robot is mechanically moved to the origin position as described above to obtain the origin offset after the robot exchange and store it in the origin offset storage unit 52. In step 105, the origin offset is obtained. The difference in the origin offset before and after the robot exchange stored in the storage unit 52 is obtained as the first deviation amount and stored in the origin offset storage unit 52. Subsequently, in step 106, the same measuring jig as used in step 102 is mounted on the robot, and the robot is moved to a predetermined position using the teaching data corrected based on the first deviation amount. Then, 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 Q. In step 107, the second shift amount is obtained from the difference between the position P and the position Q and stored in the predetermined position coordinate storage unit 53.

  Next, in step 108, the robot is moved to the origin position by a command input to the robot controller 40, and then the robot is moved from the origin position to a predetermined position using the teaching data corrected based on the first deviation amount and the second deviation amount. 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 R. In step 109, it is determined whether or not the difference between the position P obtained before exchanging the robot and the position R obtained this time exceeds an allowable value. When the allowable value is exceeded, the second deviation amount is not accurately obtained. Therefore, in step 110, the second deviation amount is recalculated based on the difference between the position P and the position R, and the predetermined position coordinates are stored. Store in the unit 53. In the recalculation of the second deviation amount, the second deviation amount before the recalculation had a deviation exceeding the allowable value at the position P and the position R, so the second deviation amount was corrected so as to eliminate this deviation. An operation for obtaining a value to be performed is performed. After execution of step 110, the process returns to step 108, and the processing from step 108 to step 110 is repeated until the difference between the position P and the position R is within an allowable value. If the difference between the position P and the position R is within the allowable value in step 109, it is determined that the second deviation amount has been determined, and the process is terminated.

  After the first deviation amount and the second deviation amount are determined 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 exchanging the robot is processed. By performing the correction based on the first deviation amount and the second deviation amount, the teaching data can be continuously used even after the robot is replaced.

  According to the embodiment described above, the first deviation amount based on the origin offset and the second deviation amount based on the predetermined position coordinates are separately calculated, stored, and managed to detect an abnormal value in the deviation amount. The teaching data used before the robot replacement can be changed after the robot replacement without re-teaching by correcting the teaching data using the first deviation amount and the second deviation amount. Can also be used. The robot controller 40 shown in FIG. 2 can manage the origin offset and the predetermined position coordinates separately. However, the hardware configuration is not different from a general robot controller. The form position information restoration method can be realized by using a general robot controller.

  In the position information restoration method of the present embodiment described above, the predetermined position coordinates are obtained using one reference marker 24 provided in the processing chamber 22, but two reference markers 24 provided in the processing chamber 22 are used. By using it, it becomes possible to separately acquire the deviation of the installation position and the deviation of the direction, and the second deviation amount can be obtained accurately in a short time. FIG. 5 shows an example in which two reference markers 24 are provided in the processing chamber 22 and a camera 23 is arranged corresponding to each of the two reference markers 24. When the predetermined position coordinates are obtained using the two reference markers 24, the displacement of the installation position and the displacement of the orientation are obtained separately, so that the first deviation amount is obtained by performing only rough adjustment by the origin sensor. Even if the values are 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, two reference markers 24 can be photographed using a single camera 23 so that a measurement jig is reflected. It is possible to obtain the installation position deviation and the orientation deviation separately. If a square measurement jig is used, when two reference markers 24 are used, the reference markers 24 may be arranged corresponding to the vertices on both sides of one diagonal line of the jig. By doing so, it is possible to increase the distance between the two positions where the edge of the jig is detected, so that it is possible to accurately detect the deviation in the direction.

  The robot shown in FIG. 1 is a horizontal articulated robot in which arms 12 and 13 and a hand 14 are connected in this order to a base 11, but a robot to which the position information restoring method of the present invention can be applied. It is not limited. The robot shown in Patent Document 5 includes 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, Although it is a horizontal articulated robot that includes a hand connected to the tip of the arm and a mechanism that is provided on the base and moves up and down the base side link, the movement of the tip of the arm side link is regulated by the link mechanism. The present invention can also be applied to such a robot. Furthermore, the present invention can be applied to a vertical articulated robot.

  DESCRIPTION OF SYMBOLS 11 ... Base; 12, 13 ... Arm; 14 ... Hand; 15 ... Motor; 16 ... Encoder; 21 ... Transfer chamber; 22 ... Processing chamber; 23 ... Camera; 24 ... Reference marker; 41 ... Bus; 42 ... Servo circuit; 43 ... CPU; 44 ... Storage; 51 ... Teaching data storage; 52 ... Origin offset storage; 53 ... Predetermined position coordinate storage; 60 ... Teaching pendant.

Claims (9)

A method for restoring position information of a robot that is used in a processing apparatus having a plurality of processing chambers and supports and conveys an object between the plurality of processing chambers based on teaching data,
The robot includes a base installed in the processing apparatus, a hand that supports the object, and at least one arm interposed between the base and the hand,
Replacement of a part of the robot, reassembly of a part or all of the robot, or transfer of the robot is a robot replacement, and before the robot replacement is performed, the origin offset of the robot and the hand are extended and predetermined. Storing a predetermined position coordinate indicating the position and posture of the robot when moved to a position;
Obtaining an origin offset of the robot after the robot exchange, and storing a first deviation amount which is a difference between the origin offset before the robot exchange and the origin offset after the robot exchange;
After the robot replacement, the hand is extended to move the robot to the predetermined position to obtain the predetermined position coordinates, and the predetermined position coordinates before the robot replacement and the predetermined position coordinates after the robot replacement Calculating and storing a second shift amount based on the difference between
Have
A position information restoration method for managing the first deviation amount and the second deviation amount separately.   The processing apparatus includes 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 obtain the position of the object, whereby coordinates different from the robot are obtained. The position information restoration method according to claim 1, wherein the predetermined position coordinates in the system are acquired.   After the robot replacement, the robot is brought to the origin position by coarse adjustment by an origin sensor provided in the robot and fine adjustment by fitting means for regulating the position between structures included in the robot. The position information restoration method according to claim 1, wherein the origin offset is acquired by moving the position offset.   The processing apparatus includes two reference markers, and at least a part of an object mounted on the hand and the reference marker are imaged by a visual sensor to obtain the position of the object, and is separated from the robot. The position information restoration method according to claim 1, wherein the predetermined position coordinates in a coordinate system are acquired.   5. The object is a quadrangular shape, and the two reference markers are provided at positions corresponding respectively to both ends of one diagonal line of the object when the robot is at the predetermined position. The location information restoration method described in 1.   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 position information restoration method according to claim 6, wherein the predetermined position is a position when the hand is farthest from the base in the processing chamber in which the reference marker is provided.   The position information restoration method according to any one of claims 1 to 7, wherein the robot is moved to the predetermined position based on the teaching data actually used in the robot.   The teaching data is corrected using the first deviation amount and the second deviation amount until the deviation of the predetermined position coordinates before and after the robot replacement is within an allowable range, and based on the corrected teaching data. The position information restoration method according to claim 8, wherein the robot is moved from the origin position to the predetermined position and the second shift amount is recalculated.

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