JP6984711B1 - Robot position calibration system, robot position calibration method and robot position calibration program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calibrate a position of a robot with a simple system configuration by a simple operation of the robot. SOLUTION: Two measurement objects 51 and 52 are provided on one of an arm 11 of a robot 3 and a work space 2, and a sensor 45 is provided on the other side. When the controller 30 drives the arm 11 to move the sensor 45 relative to the two measurement objects 51 and 52, and the sensor 45 measures the two measurement objects 51 and 52, respectively. The two positions xr1 and xr2 of the arm 11 are acquired. The controller 30 is a robot 3 based on the measurement distance between the two measurement objects 51 and 52 obtained from the two acquired positions xr1 and xr2 and the actual distance between the two measurement objects 51 and 52. The amount of angular deviation ΔΘ in the reference plane RS is measured. [Selection diagram] FIG. 5

Description

The present invention relates to a robot position calibration system, a robot position calibration method and a robot position calibration program which are suitably applied during teaching.

After the robot is installed in the work space, teaching work for setting teaching points is performed before the robot is put into actual operation. In actual operation, the robot controller controls the movement of the arm so that the end effector is sequentially positioned at a plurality of teaching points set in the robot coordinate system, and the robot is made to perform the required work in the workspace.
Here, the robot may be installed in the work space in a state where the robot coordinate system deviates from the design value due to the assembly error or the installation error of the robot. Therefore, the teaching work is accompanied by a calibration work for calibrating the robot coordinate system and thus the teaching point. The calibration work can occur not only at the time of new delivery to the robot work space, but also after the robot maintenance work. Conventionally, a technique for automating proofreading work and saving labor in teaching work has been proposed (see, for example, Patent Document 1).

In Patent Document 1, a jig dedicated to teaching having three or more edges is installed in the work space. On the other hand, the robot holds a detection jig having a non-contact displacement sensor at its tip. By rotating the non-contact displacement sensor with the non-contact displacement sensor facing the teaching jig in the vertical direction, three or more edges are measured by the non-contact displacement sensor. Based on this measurement result, the amount of positional deviation and the amount of angular deviation in the horizontal plane of the robot coordinate system are measured.

Japanese Patent No. 62324091

The above method requires measurement of three or more points, and the operation of the robot for measurement is complicated.
Therefore, an object of the present invention is to provide a system, a method and a program capable of calibrating the position of a robot with a simple system configuration by a simple robot operation.

The robot position calibration system according to one embodiment of the present invention includes two measurement objects, a sensor, and a controller. The two measurement objects are provided in either the arm of the robot or the work space in which the robot is installed, and are separated from each other in the reference plane. The sensor is provided on the other side of the arm and the work space, and measures two measurement objects. The controller drives and controls the arm of the robot. By driving the arm, the controller moves the sensor relative to the two measurement objects, and acquires and acquires the two positions of the arm when the sensor measures each of the two measurement objects. In the reference plane of the robot based on the measurement distance in the reference plane between the two measurement objects obtained from the two positions and the actual distance in the reference plane between the two measurement objects. Measure the amount of angle deviation.

Here, the robot coordinate system includes a three-dimensional orthogonal coordinate system (XrYrZr coordinate system), of which two axes (Xr axis and Yr axis) form a reference plane. The device coordinate system of the work space in which the robot is installed includes a three-dimensional Cartesian coordinate system (XYZ coordinate system), of which two axes (X-axis and Y-axis) form a reference plane. That is, the robot is in the work space so that the axis (Zr axis) extending along the reference plane normal among the three axes of the robot coordinate system is parallel or coaxial with the corresponding axis (Z axis) in the device coordinate system. Will be installed in.

When the robot is installed in the work space in a state where it deviates from the design value due to an installation error or the like, the robot coordinate system becomes a reference plane with respect to the device coordinate system or the assumed arrangement of the robot coordinate system. Internal angular deviation (angle deviation around the Zr axis), positional deviation in the reference plane (positional deviation in the Xr direction and Yr direction), or positional deviation in the normal direction of the reference plane (positional deviation in the Zr direction) occurs. The reference plane is typically a horizontal plane. In that case, the amount of angle deviation in the reference plane is the amount of angle deviation in the horizontal plane (the amount of angle deviation around the vertical axis).

According to the above configuration, such an angle deviation amount can be measured, and the calibration work of the robot coordinate system can be automated.
That is, when the sensor moves relative to the two measurement objects due to the drive control of the arm by the controller, the measurement object is measured by the sensor in the process. The distance between the objects to be measured in the reference plane is measured from the two positions of the arm at the time of measurement. This measured distance is compared to the actual distance within the same reference plane. As described above, if the robot is installed so that the Zr axis coincides with the Z axis, the controller can measure the distance in the reference plane and grasp the actual distance in the reference plane in advance. Both are easy.

This difference between the measured distance and the actual distance is due to the amount of angular deviation in the reference plane. The difference in distance geometrically correlates with the amount of angular deviation (see FIG. 11). Therefore, the amount of angular deviation in the reference plane can be measured by a simple robot operation of measuring two measurement objects.
The controller may move the arm linearly in one direction in the reference plane when moving the sensor relative to the object to be measured.

If the arm moves linearly in one direction, the difference in the position coordinates in the one direction becomes the measurement distance as it is. According to the above configuration, the calculation load can be reduced, the number of measurements can be reduced, and the amount of angle deviation can be measured.
The sensor may emit an ultrasonic or light measuring medium and measure the measuring object based on the reflection of the measuring medium on the measuring object. When the sensor is moved relative to the object to be measured, the controller may move the arm so that the ejection direction of the measuring medium is orthogonal to the moving direction of the arm in the reference plane.

If the ejection direction of the measuring medium is orthogonal to the moving direction of the arm, it is not necessary to consider the deviation of the measuring medium in the ejection direction with respect to the moving direction of the arm. The amount of deviation can be measured by reducing the number of measurement objects to be measured and reducing the number of measurements.
The controller corrects the robot coordinate system so that the measured angle deviation amount cancels out, and drives the arm while controlling the position of the arm in the corrected robot coordinate system, thereby making the sensor two measurement targets. By moving relative to the object, the position of the arm when the sensor measures one of the two measurement objects is acquired, and the robot's position is based on the acquired position and the actual position of the measurement object. The amount of misalignment in the reference plane may be measured.

Under the situation where the angle deviation in the reference plane is offset, the difference between the measured position and the actual position in the reference plane is due to the amount of the position deviation in the reference plane. According to the above configuration, the amount of positional deviation can also be measured by operating a simple robot that measures one measurement object.
By driving the arm, the controller moves the sensor relative to the two measurement objects in the normal direction of the reference plane, and the position of the arm when the sensor measures one of the measurement objects. May be acquired, and the amount of positional deviation in the normal direction of the robot may be measured based on the acquired position and the actual position of the measurement object.

According to the above configuration, the amount of positional deviation in the normal direction of the reference plane can be measured by a simple robot operation.
The sensor may be attached to the arm, two measurement objects may be provided in the work space, and the two measurement objects may be components of the device installed in the work space.
According to the above configuration, the position of the robot can be calibrated without separately providing a dedicated measuring jig. The system configuration can be simplified.

The robot position calibration method according to one embodiment of the present invention includes two measurement objects separated from each other in a reference plane, and an arm, which are provided in either the robot arm or the work space in which the robot is installed. It is used in a robot position calibration system provided on the other side of the work space and equipped with a sensor for measuring two measurement objects. The robot position calibration method is to move the sensor relative to the two measurement objects by driving the arm, and to determine the two positions of the arm when the sensor measures each of the two measurement objects. The robot is based on the acquisition, the measurement distance in the reference plane between the two measurement objects obtained from the two acquired positions, and the actual distance in the reference plane between the two measurement objects. It is provided with measuring the amount of angular deviation in the reference plane of.

The robot position calibration program according to one embodiment of the present invention causes a computer to execute the robot position calibration method.
The above method and program have technical features corresponding to the above-mentioned robot position calibration system, and have the same effects as the above-mentioned robot position calibration system.

According to the present invention, the position of the robot can be calibrated with a simple system configuration by a simple robot operation.

It is a top view of the semiconductor processing equipment to which the robot calibration system which concerns on embodiment of this invention is applied. It is a front view of the robot in the state shown in FIG. It is a top view of the robot position calibration system which concerns on embodiment of this invention, and is the top view which shows the state in which a reference plane calibration process is being executed. It is a front view of the robot position calibration system in the state shown in FIG. It is a block diagram which shows the robot position calibration system which concerns on embodiment of this invention. It is a flowchart which shows the robot position calibration method which concerns on embodiment of this invention. It is explanatory drawing of the deviation in the reference plane with respect to the device coordinate system of a robot coordinate system. It is a flowchart which shows the reference plane calibration process shown in FIG. It is an operation diagram of the angle calibration process. (A) shows an example of the relative movement range of the sensor with respect to the measurement object, (B) shows the time point when the first measurement object is measured, and (C) shows the time point when the second measurement object is measured. It is a graph which shows the relationship of the input of a sensor with respect to the Xr direction position of an arm. It is explanatory drawing of the angle calibration process. It is explanatory drawing of the correction process of the robot coordinate system after the angle calibration process. It is explanatory drawing of the position calibration process. It is a flowchart which shows the normal calibration process shown in FIG. It is a top view of the robot position calibration system which concerns on embodiment of this invention, and is the top view which shows the state in which a normal calibration process is being executed. It is a front view of the robot position calibration system in the state shown in FIG. It is explanatory drawing of the normal calibration process. It is explanatory drawing of the deviation in the reference plane with respect to the apparatus coordinate system of the robot coordinate system which concerns on a modification. It is a top view of the robot position calibration system which concerns on the modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(robot)
1 and 2 show a semiconductor manufacturing facility 1 to which the robot position calibration system 100 according to the embodiment of the present invention is applied. In the semiconductor manufacturing facility 1, a work space 2 maintained in a clean environment is formed, and a disk-shaped semiconductor wafer W is transported and manufactured in the work space 2. The semiconductor manufacturing equipment 1 includes one or more robots 3 and a plurality of mounting portions 4 (only one is shown in the figure), and these are arranged in the work space 2.

The mounting unit 4 may be any as long as it has a function of mounting the semiconductor wafer W. The mounting portion 4 may be realized by a container for accommodating a semiconductor wafer W such as a FOUP (Front Opening Unified Pod). The mounting portion 4 may be realized by an aligner for positioning the semiconductor wafer W. The mounting unit 4 may be realized by a processing device that carries out various steps (cleaning, film formation, exposure, etc.) of the semiconductor manufacturing process. The mounting unit 4 may be realized by a load port which is an interface between the container and the processing device.

In the illustrated example, the mounting portion 4 is composed of a base 5 installed on the floor surface of the work space 2 and a plurality of pins 6 provided on the upper surface of the base 5. The plurality of pins 6 project upward by the same distance from the upper surface of the base 5. The plurality of pins 6 are arranged at equal intervals in the circumferential direction with the central axis C4 of the mounting portion 4 as the center. The semiconductor wafer W is mounted on a plurality of pins 6 and supported by the mounting portion 4 in a horizontal posture.

The robot 3 conveys the semiconductor wafer W from one mounting unit 4 to another mounting unit 4 in the work space 2. The robot 3 includes a base 10 and an arm 11. The base 10 is installed on the floor surface of the work space 2 via the spacer 15.
The arm 11 has an elevating shaft 12 that expands and contracts with respect to the base 10, a plurality of links 13a and 13b sequentially connected from the elevating shaft 12, and a hand 14 attached to the tip of these links 13a and 13b. .. The hand 14 holds the semiconductor wafer W releasably.

In this document, not only the plurality of links 13a and 13b but also the hand 14 which is an end effector constitutes a part of the "arm 11". The plurality of links 13a and 13b are arms in a narrow sense, and the elevating shaft 12 and the plurality of links 13a and 13b are effector moving mechanisms that displace the hand 14 which is an end effector.
The robot 3 is, for example, a two-link type horizontal articulated robot. The arm 11 has a first link 13a and a second link 13b. The base end portion of the first link 13a is rotatably connected to the upper end portion of the elevating shaft 12 around the first rotation shaft A1. The base end portion of the second link 13b is rotatably connected to the tip end portion of the first link 13a around the second rotation axis A2. The hand 14 is rotatably connected to the tip of the second link 13b (the tip of the link group as a whole) around the third rotation axis A3.

The elevating shaft 12, the first link 13a, the second link 13b, and the hand 14 are stacked in this order from the base 10, and the rotation shafts A1 to A3 are parallel to each other. As a result of the inclination adjustment of the spacer 15 at the time of installing the robot, the elevating shaft 12 and the rotating shafts A1 to A3 are oriented vertically.
The robot 3 has an elevating actuator 20 that expands and contracts the elevating shaft 12, a first rotating actuator 21 that rotates the first link 13a around the first rotating shaft A1, and a second rotating actuator 21 that rotates the second link 13b around the second rotating shaft A2. A rotary actuator 22 and a third rotary actuator 23 for rotating the hand 14 around the third rotary axis A3 are provided. When the elevating actuator 20 operates, the hand 14 is displaced in the vertical direction according to the expansion / contraction operation of the elevating shaft 12. When the rotary actuators 21 to 23 operate, the hand 14 is displaced in the horizontal plane according to the rotational movement of the links 13a and 13b and the hand 14.

Each actuator 20 to 23 is configured by an electric motor as an example. In order to convert the rotation generated by the elevating actuator 20 into the translation of the elevating shaft 12, the robot 3 may be provided with a motion conversion mechanism such as a ball screw mechanism.
The shape of the hand 14 and the type of holding are not particularly limited. As illustrated in FIGS. 1 and 2, the hand 14 is made of a thin plate material and is formed in a U-shape or a Y-shape in a plan view. The hand 14 has a proximal end portion 16 and a pair of distal end portions 17 extending from the proximal end portion 16. The hand 14 is formed line-symmetrically with respect to the hand center line C14 in a plan view. The base end portion 16 is rotatably connected to the tip end portion of the link group.

The hand 14 is configured to suck the semiconductor wafer W by a suction mechanism or mechanically grip it by a chuck mechanism. In the present embodiment, as an example of the holding mechanism, the suction portion 18 is provided on the lower surface of each of the pair of tip portions 17. In addition, a plurality of chuck portions for gripping the semiconductor wafer W may be provided on the upper surface of the hand 14. The robot 3 includes a holding actuator 24 (see FIG. 5) that operates a holding mechanism such as a chuck portion and a suction portion 18.

The transfer of the semiconductor wafer W from the mounting unit 4 to the hand 14 during the actual operation of the robot 3 will be described. The semiconductor wafer W is mounted on the mounting portion 4 with its center located on the central axis C4 of the mounting portion 4. First, the empty hand 14 is positioned above the mounting portion 4. At this time, the reference point on the hand center line C14 is overlapped with the central axis C4 of the mounting portion 4 in a plan view. Next, the hand 14 is lowered until the clearance between the hand 14 and the semiconductor wafer W reaches a predetermined value. Next, the holding actuator 24 (see FIG. 5) is operated. As a result, the semiconductor wafer W is separated from the pin 6 and the hand 14 holds the semiconductor wafer W (FIG. 2 shows this timing). In the holding state, the center of the semiconductor wafer W overlaps with the reference point of the hand 14 in a plan view. By moving the hand 14, the semiconductor wafer W is conveyed in the work space 2.

The transfer of the semiconductor wafer W from the hand 14 to the mounting portion 4 is the same as described above. First, the hand 14 in the held state is positioned above the mounting portion 4. At this time, the reference point on the hand center line C14 and thus the center of the semiconductor wafer W are overlapped with the central axis C4 of the mounting portion 4 in a plan view. Next, the hand 14 is lowered until the clearance between the semiconductor wafer W and the pin 6 reaches a predetermined value (FIG. 2 shows this timing). Next, the holding actuator 24 (see FIG. 5) is stopped. As a result, the semiconductor wafer W is released from the hand 14 and placed on the mounting portion 4 with its center located on the central axis C4 of the mounting portion 4. The hand 14 may scoop up the semiconductor wafer W from below and hold it.

The hand 14 moves in the work space 2 as described above by controlling the operation of the actuators 20 to 23 so as to be sequentially positioned at a plurality of preset teaching points in the robot coordinate system CSr.
The robot coordinate system CSr is a coordinate system in which the origin is placed on the robot 3. The robot coordinate system CSr includes both a three-dimensional Cartesian coordinate system and a three-dimensional polar coordinate system, but this document describes the robot coordinate system as a three-dimensional Cartesian coordinate system unless otherwise specified. The origin is set on the immovable base 10 regardless of the operation of the arm 11. The robot coordinate system CSr is composed of an Xr axis, a Yr axis, and a Zr axis that are orthogonal to each other.

On the other hand, the device coordinate system CS1 is set in the semiconductor manufacturing equipment 1. The device coordinate system CS1 is a three-dimensional Cartesian coordinate system in which the origin is placed at an arbitrary position (for example, the floor surface) of the work space 2, and is composed of X-axis, Y-axis, and Z-axis that are orthogonal to each other. The X-axis and Y-axis form a horizontal plane, and the Z-axis extends vertically.
The Xr and Yr axes of the robot coordinate system CSr form a reference plane RS, and the Zr axis extends along the normal of the reference plane RS. The rotation axes A1 to A3 are parallel to the Zr axis. As described above, the robot 3 is installed in a posture in which the reference plane RS forms a horizontal plane and the Zr axis extends vertically by the installation using the spacer 15. In this embodiment, the Zr axis is parallel to the Z axis.

However, the robot 3 is displaced with respect to the design value in the reference plane RS (positionally displaced in the Xr direction or Yr direction), and is angularly displaced around the normal of the reference plane RS (around the Zr axis). It may be installed in the work space 2 in a state where the angle is displaced (in a state where the angle is displaced) or in a state where the position is displaced in the normal direction (a state where the position is displaced in the Zr direction). As a result, the positional relationship between the robot coordinate system CSr and the device coordinate system CS1 also deviates from the design value. When the teaching points set in the robot coordinate system CSr are referred to, the position of the hand 14 cannot be precisely controlled with respect to the constituent devices (mounting unit 4, etc.) of the semiconductor manufacturing equipment 1, and the semiconductor wafer cannot be controlled. The position of W cannot be controlled precisely.

In the following, the design value of the distance in the Xr direction with respect to the device coordinate system CS1 of the robot coordinate system CSr is set to "ax0", the design value of the distance in the Yr direction is set to "ay0", and the deviation amount with respect to the design value ax0 in the Xr direction is set to "ax0". "Δx", the amount of deviation with respect to the design value ay0 in the Yr direction is "Δy", the design value of the angle around the Zr axis is "Θ0", and the amount of deviation of the angle around the Zr axis with respect to the design value Θ0 is "ΔΘ". (See FIGS. 7 and 18). In this embodiment, the design value Θ0 of the angle is 0 degrees, and in the ideal state, the Xr axis is parallel to the X axis and the Yr axis is parallel to the Y axis. Therefore, the angle deviation amount ΔΘ is an angle formed by the Xr axis and the X axis, or an angle formed by the Yr axis and the Y axis. Further, the design value of the distance in the Zr direction is set to "az0", and the amount of deviation from the design value az0 in the Zr direction is set to "Δz" (see FIG. 16).

(Robot position calibration system)
3 to 5 show the robot position calibration system 100 according to the present embodiment. The robot position calibration system 100 is suitably applied to the semiconductor manufacturing equipment 1 as described above, and the amount of deviation of the robot coordinate system CSr with respect to the device coordinate system CS1 (or with respect to the design value) Δx, Δy, ΔΘ, Δz (FIG. 7, FIG. (See FIG. 16). This measurement is performed to calibrate the robot coordinate system CSr before the actual operation of the robot 3, such as when the robot 3 is newly delivered to the work space 2 or after the maintenance work of the robot 3.

As shown in FIGS. 3 to 5, the robot position calibration system 100 includes two measurement objects 51 and 52, a sensor 45, a controller 30, and encoders 40 to 43. The controller 30 and the encoders 40 to 43 are also used during the actual operation of the robot 3. The robot position calibration system 100 operates with the hand 14 empty, and the holding actuator 24 and the suction unit 18 are not used in the system 100.

With reference to FIGS. 3 and 4, the two measurement objects 51 and 52 are provided in either the arm 11 of the robot 3 or the work space 2. The sensor 45 is provided on the other side. As described above, the "arm 11" includes the links 13a and 13b as well as the hand 14. "Provided in the work space 2" means that it is provided at an arbitrary position other than the arm 11 in the work space 2.

In the present embodiment, the two measurement objects 51 and 52 are components of a device other than the robot 3 installed in the work space 2, and as an example, the pin 6 of the mounting portion 4. In the present embodiment, the mounting portion 4 includes three pins 6, two of which are also used as measurement objects 51 and 52 in the robot position calibration system 100.
The sensor 45 is provided on the arm 11 of the robot 3, more specifically on the hand 14. In this embodiment, the hand 14 holds the semiconductor wafer W on its lower surface. The sensor 45 is detachably attached to the upper surface on the opposite side thereof. The sensor 45 may be used during actual operation, or may be removed during actual operation as in the present embodiment (see FIG. 1).

The sensor 45 has an output unit (not shown) that emits ultrasonic waves or light as the measurement medium L, and an input unit (not shown) that inputs the measurement medium L reflected by the measurement objects 51 and 52. The sensor 45 measures the measurement objects 51 and 52 based on the reflection of the measurement medium L on the measurement objects 51 and 52. Regarding the measurement content, the sensor 45 may only detect the presence of the measurement objects 51 and 52 in the injection direction of the measurement medium L, and detects the distance from the sensor 45 to the measurement objects 51 and 52 in the injection direction. You may. As described above, the sensor 45 may be realized by an ultrasonic sensor or a photoelectric sensor and may have a function of distance measurement or displacement detection as well as a function of presence / absence detection.

In the present embodiment, as an example, the sensor 45 ejects the measurement medium L in parallel with the hand center line C14. This "parallel" also includes the case where the measurement medium L overlaps the hand center line C14 in a plan view as in the present embodiment. However, this is only an example, and the measurement medium L may be ejected in parallel with the hand center line C14 at a position deviated from the hand center line C1 in a plan view, and the measurement medium L may be ejected to the hand center line C1. On the other hand, it may be ejected in a direction of inclination.

The objects to be measured 51 and 52 are required to be easily measured by the sensor 45. The pin 6 of the mounting portion 4 protrudes from the upper surface of the flat base 5, and the periphery thereof is widely opened for mounting the semiconductor wafer W. Therefore, when the sensor 45 ejects the measurement medium L around the pin 6, it is possible to prevent erroneous detection of objects other than the pin 6 as objects 51 and 52 to be measured. Therefore, the pin 6 is suitably used as the measurement objects 51 and 52.

With reference to FIG. 5, the controller 30 has a CPU 31, a memory 32 and an input / output interface 33, which are interconnected via a communication bus.
The input / output interface 33 is connected to the actuators 20 to 24, the encoders 40 to 43, and the sensor 45. The encoders 40 to 43 are provided corresponding to the actuators 20 to 23, and detect the operating position (for example, the rotation position of the electric motor) of the corresponding actuators 20 to 23.

The CPU 31 controls the operations of the actuators 20 to 24 according to the work program 34 stored in the memory 32. As a result, the robot 3 can perform the required work in the work space 2, and the semiconductor manufacturing equipment 1 can be actually operated. The work program 34 includes teaching points set before the actual operation. The CPU 31 derives the position and posture of the arm 11 from the operating positions of the actuators 20 to 23 detected by the encoders 40 to 43 by an inverse transformation process, and feeds back the derived position and posture to move the arm 11. As described above, the encoders 40 to 43 are an example of the arm position detector that detects the position of the arm 11.

The CPU 31 controls the operations of the actuators 20 to 23 according to the robot position calibration program 35 stored in the memory 32, and drives and controls the arm 11. In the drive control of the arm 11, the position and posture of the arm 11 are derived from the operating positions of the actuators 20 to 23 detected by the encoders 40 to 43, and the derived positions and postures are fed back in the same manner as described above. .. In the robot position calibration program 35, the measurement result of the sensor 45 is referred to, and the position of the arm 11 derived based on the detection results of the encoders 40 to 43 is referred to.

The memory 32 is composed of a storage device such as a ROM, a RAM, and an EEPROM. In addition to the work program 34 and the robot position calibration program 35, information or data necessary for processing executed according to these programs 34 and 35 is temporarily stored.
The memory 32 stores the device design data 36 at least for reference in the robot position calibration program 35. The device design data 36 indicates the positions or dimensions of various devices installed in the work space 2.

In this embodiment, two measurement objects 51 and 52 are provided in the work space 2. The device design data 36 uses coordinate values (x1, y1) and (x2, y2) indicating the positions of the two measurement objects 51 and 52 defined in the device coordinate system CS1 of the two measurement objects 51 and 52. Included as information indicating the actual position. The device design data 36 may include information indicating the actual distance between the two measurement objects 51 and 52. The actual distance includes the linear distance between the two measurement objects 51 and 52, as well as the distance of the X component (x2-x1) and the distance of the Y component (y2-y1). Further, the device design data 36 includes data indicating the design values ax0, ay0, and az0 of the distances in the Xr direction, the Yr direction, and the Zr direction between the origin of the robot coordinate system CSr and the origin of the device coordinate system CS1. The device design data 36 includes data indicating a design value Θ0 of the angle around the Zr axis with respect to the device coordinate system CS1 of the robot coordinate system CSr.

The robot position calibration program 35 causes a computer to execute the robot position calibration method used in the robot position calibration system 100. The CPU 31 or the controller 30 including the CPU 31 is an example of such a computer. In the present embodiment, the robot position calibration program 35 is stored in the controller 30 that controls the operation of the robot 3 during actual operation, but is stored in another computer communicably connected to such a controller 30. It may have been done.

(Robot position calibration method)
FIG. 6 shows a robot position calibration method according to an embodiment of the present invention. The robot position calibration method includes a reference plane calibration process S10 and a normal calibration process S40. The reference plane calibration process S10 includes an angle calibration process S20 and a position calibration process S30. Which of the reference plane calibration process S10 and the normal calibration process S40 may be executed first. The angle calibration process S20 is executed before the position calibration process S30.

In the reference plane calibration process S10, the deviation amount Δx, Δy, ΔΘ in the reference plane RS (in the XrYr plane or the horizontal plane) is measured, and the robot coordinate system CSr is calibrated based on the measured deviation amount Δx, Δy, ΔΘ. (See FIGS. 7 to 13). The angle deviation amount ΔΘ is measured in the angle calibration process S20, and the position deviation amounts Δx and Δy are measured in the position calibration process S30. In the normal calibration process S40, the deviation amount Δz in the normal direction (Zr axis direction or vertical direction) of the reference plane RS is measured, and the robot coordinate system CSr is calibrated based on the measured deviation amount Δz (FIG. 14). ~ See FIG. 17).

(Reference surface calibration process)
FIG. 7 shows the deviation of the robot coordinate system CSr with respect to the device coordinate system CS1 in the reference plane RS. Here, the coordinates of the point P in the device coordinate system CS1 are (x, y), and the coordinates in the robot coordinate system CSr are (xr, yr).
When the robot coordinate system CSr is arranged as designed (see two-dot chain line), in this embodiment the design value Θ0 is 0 degrees, and the Xr and Yr axes are parallel to the X and Y axes, respectively. The origin of the robot coordinate system CSr is separated from the origin of the device coordinate system CS1 by the design value ax0 in the Xr direction and by the design value ay0 in the Yr direction. The positional relationship between the robot coordinate system CSr and the device coordinate system CS1 satisfies the ideal states of xr = x + ax0 and yr = y + ay0.

On the other hand, when the robot coordinate system CSr is arranged in the reference plane RS with the positional deviation and the angular deviation (see the solid line), the positional relationship between the robot coordinate system CSr and the device coordinate system CS1 is determined. It is represented by xr = ax0 + Δx + xcosΔΘ + ysinΔΘ, yr = ay0 + Δy−xcosΔΘ + ysinΔΘ. If the controller 30 does not recognize the deviation amounts Δx, Δy, ΔΘ in the reference plane RS, the controller 30 expresses the positional relationship between the coordinate systems CSr and CS1 as xr = x + ax0 and yr = y + ay0 during actual operation. Recognizing that it is in the ideal state, it misidentifies that the point P is at the position of the point Perr. For example, when the mounting portion 4 is present at the point P, the semiconductor wafer W cannot be accurately transferred.
FIG. 8 shows the procedure of the reference plane calibration process S10. 9 to 13 are explanatory views of the reference plane calibration process S10. The reference plane calibration process S10 proceeds in the order of the angle calibration process S20 and the position calibration process S30. The operation of the actuators 20 to 23 and the position of the hand 14 described below are controlled by the controller 30.

(Angle calibration process)
In the angle calibration process S20, first, the hand 14 moves to the initial position (S21). Specifically, with reference to FIG. 4, the height of the hand 14 is adjusted through the operation of the elevating actuator 20 so that the measurement medium L can be reflected by the measurement objects 51 and 52. With reference to FIG. 9A, the rotary actuators 21 to 23 are such that the hand 14 is slightly separated from the two measurement objects 51 and 52 on one side in the Xr direction (the left side of the paper in FIG. 9A). The position of the hand 14 in the Xr direction is adjusted through the operation of. The position of the hand 14 in the Yr direction is adjusted through the operation of the rotary actuators 21 to 23 so that the hand 14 is slightly separated from the measurement target objects 51 and 52 (or the mounting portion 4) in the Yr direction. The posture of the hand 14 in the reference plane RS is adjusted through the operations of the rotary actuators 21 to 23 so that the injection direction of the hand center line C14 and the measurement medium L is the Yr direction. Since the controller 30 does not recognize the angle deviation of the Yr axis with respect to the Y axis at this point, the Yr direction is inclined with respect to the Y direction.

Next, the hand 14 is moved in the Xr direction while operating the sensor 45 (S22). As a result, the sensor 45 moves linearly and relative to the two measurement objects 51 and 52 in the Xr direction. Since the controller 30 does not recognize the angle deviation of the Xr axis with respect to the X axis at this point, the Xr direction is inclined with respect to the X direction. However, the moving direction of the hand 14 is not limited to the Xr direction.

With reference to FIG. 9A, the hand 14 moves to a position distant from the two measurement objects 51 and 52 on the other side in the Xr direction (on the right side of the paper in FIG. 9A). In the process, the measurement medium L is first reflected by the first measurement object 51 (see FIG. 9B) and then reflected by the second measurement object 52 (see FIG. 9C).
The controller 30 acquires the position xr1 of the hand 14 in the Xr direction when the first measurement object 51 is measured by the sensor 45 (S23). Further, the controller 30 acquires the position xr2 of the hand 14 in the Xr direction when the second measurement object 52 is measured by the sensor 45 (S24). Hereinafter, the two positions acquired here will be referred to as "first measurement position xr1" and "second measurement position xr2". The two measurement positions xr1 and xr2 are derived from the detection results of the encoders 41 to 43.

FIG. 10 shows the strength of the measuring medium L input to the sensor 45. The objects to be measured 51 and 52 have a width (for example, 5 mm) in the X direction (Xr direction). On the other hand, the moving speed of the hand 14 is set to a low value so as not to move a distance exceeding the width of the measurement objects 51 and 52 during the measurement cycle of the sensor 45. Therefore, while the hand 14 is moving, the sensor 45 can input reflections from the two measurement objects.

The first measurement position xr1 is the position where the measurement medium L starts to pass through the first measurement object 51 and the strength of the measurement medium L rises, and the measurement medium L finishes passing through the first measurement object 51. It is set between the position where the intensity converges. For example, the first measurement position xr1 is set to an intermediate position between these two positions. The same applies to the second measurement position xr2.
Two of the three pins 6 are also used as the measurement objects 51 and 52, and while the hand 14 is moving, the pins 6 that are not used as the measurement objects 51 and 52 are detected by the sensor 45 (two). See dotted line). In this case, for the measurement objects 51 and 52, two pins 6 separated in the Xr direction are selected. By using two that are as far apart as possible in the Xr direction, the measurement accuracy of the amount of deviation is improved.

Next, the controller 30 is based on the measurement distance between the two measurement objects 51 and 52 in the reference plane RS and the actual distance between the two measurement objects 51 and 52 in the reference plane RS. , The amount of angle deviation ΔΘ is measured (S25). With reference to FIG. 11, the “measurement distance” is the difference (xr2-xr1) between the first measurement position xr1 and the second measurement position xr2, and the two measurement objects 51 measured in the robot coordinate system CSr. , 52 is the distance in the Xr direction.

The "real distance" is the actual distance between the two measurement objects 51 and 52. Here, it is assumed that the devices other than the robot 3 are installed according to the design values. The actual distance in the X direction is the distance in the X direction between the two measurement objects 51 and 52, and is the difference value (x2-x1) of the X coordinates in the device coordinate system CS1. The actual distance in the Y direction is the distance in the Y direction between the two measurement objects 51 and 52, and is the difference value (y2-y1) of the Y coordinates in the device coordinate system CS1. As described above, the controller 30 has the coordinate values (x1, y1), (x2, y2), and the actual elements in the X direction of the two measurement objects 51 and 52 in the device coordinate system CS1 as a part of the device design data 36. The distance and the actual distance in the Y direction are stored in advance.

If there is no angle deviation, the measured distance is equal to the actual distance in the X direction. Considering the amount of angular deviation ΔΘ, the measured distance and the actual distance satisfy the formula: xr2-xr1 = (x2-x1) cosΔΘ + (y2-y1) sinΔΘ. This equation is derived from the equation representing the positional relationship between the coordinate systems CSr and CS1 shown in FIG. The amount of angular deviation ΔΘ is derived by performing mathematical processing such as synthesis of trigonometric functions on this equation.

As shown in FIG. 7, in the comparison between the positions, in addition to the angle deviation amount ΔΘ, the position deviation amount Δx in the X direction or the position deviation amount Δy in the Y direction also intervenes in the relationship between the two positions. On the other hand, in the angle calibration process S20, the distance in one direction called the Xr direction is the comparison target.
When the difference between the two measurement positions xr1 and xr2 is taken, the amount of positional deviation Δx in the X direction is offset. Further, it is not necessary to consider the amount of positional deviation Δy in the Yr direction. The actual distance is a known value. Therefore, the angle deviation amount ΔΘ can be derived according to the above equation even in a situation where the position deviation amount Δx in the X direction and the position deviation amount Δy in the Y direction are not recognized.

Further, the ejection direction of the measuring medium L is the Yr direction orthogonal to the moving direction of the hand 14. Therefore, when the sensor 45 measures the first measurement object 51, the position xr1 of the hand 14 in the Xr direction is the same as the position of the first measurement object 51 in the Xr direction. The same applies to the second measurement object 52. It is not necessary to consider the deviation in the Xr direction between the sensor 45 and the objects to be measured 51 and 52, and the angle deviation amount ΔΘ can be derived according to the above equation.
As described above, according to the present embodiment, the angle deviation amount ΔΘ can be measured with a simple system configuration by a simple operation of the robot 3.

(Position calibration process)
As a result, the angle calibration process S20 ends and the position calibration process S30 starts. The controller 30 corrects the robot coordinate system CSr so that the measured angle deviation amount ΔΘ cancels out (S29). With reference to FIG. 12, the robot coordinate system CSr is corrected so as to rotate about the Zr axis by a correction amount (−ΔΘ) that offsets the angle deviation amount ΔΘ. The reference reference numeral "CSrc" is the corrected robot coordinate system, and the "Xrc axis" and the "Yrc axis" are the two axes forming the reference plane RC in the corrected robot coordinate system CSrc. The Xrc axis is obtained by rotating the Xr axis by a correction amount of −ΔΘ, and the Yrc axis is obtained by rotating the Yr axis by a correction amount of −ΔΘ. As a result, the angle around the Zr axis of the robot coordinate system CSrc with respect to the device coordinate system CS1 becomes the design value Θ0 (0 degrees in this embodiment).

Next, the hand 14 moves to the initial position in the same manner as in step S21 (S31). With reference to FIG. 3, the position of the hand 14 in the Xrc direction is adjusted through the operation of the rotary actuators 21 to 23 so that the hand 14 is slightly separated from the measurement object 51 on one side in the Xrc direction. The position of the hand 14 in the Yrc direction is adjusted through the operation of the rotary actuators 21 to 23 so that the hand 14 is slightly separated from the measurement object 51 (or the mounting portion 4) in the Yrc direction. The posture of the hand 14 in the reference plane RS is adjusted through the operation of the rotary actuators 21 to 23 so that the injection direction of the hand center line C14 and the measurement medium L is the Yrc direction. Since the amount of angular deviation ΔΘ is offset, the Yrc direction is parallel to the Y direction, and the measurement medium L is ejected in the Y direction.

Next, in the same manner as in step S22, the hand 14 is moved in the Xrc direction while operating the sensor 45 (S32). As a result, the sensor 45 moves linearly relative to the measurement object 51 in the Xrc direction. Since the amount of angular deviation ΔΘ is offset, the Xrc direction is parallel to the X direction, and the hand 14 moves in the X direction.
Next, in the same manner as in step S23, the controller 30 acquires the position xrc1 in the Xrc direction of the hand 14 when the first measurement object 51 is measured by the sensor 45 (S33). This measurement position xrc1 is also derived from the detection results of the encoders 41 to 43. In the angle calibration process S20, two measurement objects 51 and 52 were measured, but in the position calibration process S30, one measurement object may be measured. In the present embodiment, the first measurement object 51 is measured, but the second measurement object 52 may be measured.

Next, the controller 30 acquires the position yrc1 of the first measurement object 51 in the Yrc direction (S34). The distance measuring function of the sensor 45 is used to acquire the measurement position yrc1. In the present embodiment, the position of the hand 14 and thus the sensor 45 in the Yrc direction does not change during the movement of the hand 14 in step S32. By adding the distance from the sensor 45 measured by the sensor 45 to the first measurement target 51 to the position of the moving sensor 45 in the Yrc direction, the first measurement target 51 in the corrected robot coordinate system CSrc is added. The measurement position yrc1 in the Yrc direction of is defined. Since the sensor 45 ejects the measurement medium L in the Yrc direction orthogonal to the moving direction, the Xrc component is not included in the measured distance. Therefore, the measurement position yrc1 can be acquired by a simple calculation.

Next, the controller 30 measures the position deviation amount Δx in the Xrc direction based on the measurement position xrc1 and the actual position x1 in the X direction of the first measurement object 51 (S36). The controller 30 measures the position deviation amount Δy in the Yrc direction based on the measurement position yrc1 and the actual position y1 in the Y direction of the first measurement object 51 (S37). The "actual position" is the actual position of the measurement object 51. The actual position x1 in the X direction is the X coordinate in the device coordinate system CS1 of the first measurement object 51. The actual position y1 in the Y direction is the Y coordinate of the first measurement object 51 in the device coordinate system CS1.

With reference to FIG. 13, in step S36, the position deviation amount Δx is measured based on the measurement position xrc1 and the actual position x1 in the X direction of the first measurement object 51. The difference between the two positions xrc1 and x1 is the distance ax in the X direction (the Xrc direction parallel to this) from the origin of the current robot coordinate system CSrc to the origin of the device coordinate system CS1. Since this distance ax is the sum of the design value ax0 and the position deviation amount Δx, the controller 30 can measure the position deviation amount Δx by subtracting the design value ax0 from the distance ax. As described above, the design value ax0 is stored in the memory 32 in advance as a part of the device design data 36.

Step S37 is similar to this. The difference between the two positions yrc1 and y1 is the distance ay in the Y direction (the Yrc direction parallel to this) from the origin of the current robot coordinate system CSrc to the origin of the device coordinate system CS1. The controller 30 can measure the position deviation amount Δy by subtracting the design value ay0 previously stored in the memory 32 as a part of the device design data 36 from the distance ay.

As a result, the position calibration process S30 and thus the reference plane calibration process S10 are completed. Since the deviation amounts Δx, Δy, and ΔΘ were measured with reference to FIG. 7, the controller 30 corrects the robot coordinate system CSr to the robot coordinate system CSr0 as designed even if there is an assembly error or an installation error. be able to. Therefore, the positional relationship between the robot coordinate system CSr0 and the device coordinate system CS1 is in an ideal state. The controller 30 can set the coordinate values (xr, yr) in the robot coordinate system CSr indicating the point P after recognizing the deviation amount Δx, Δy, ΔΘ (relational expression in the upper left part of the paper in FIG. 7). ), The position of the arm 11 can be precisely controlled during actual operation.

(Normal calibration process)
FIG. 14 shows the procedure of the normal calibration process S40. 15 to 17 are explanatory views of the normal calibration process S40. In the normal calibration process S40, first, the hand 14 moves to the initial position (S41). Specifically, referring to FIGS. 15 and 16, the elevating actuator 20 is such that the measuring medium L is reflected on the side surface of the base 5 (is ejected below the upper surface of the base 5). The height of the hand 14 is adjusted through the operation, and the positions of the hand 14 in the Xr direction and the Yr direction are adjusted through the operation of the rotary actuators 21 to 23. In the figure, the measuring medium L is ejected in the Xr direction, but this is for convenience of illustration, and the posture of the hand 14 in the reference plane RS is not particularly limited.

Next, the hand 14 is moved in the Zr direction while operating the sensor 45 (S42). As a result, the sensor 45 moves in the Zr direction. With reference to FIG. 16, the hand 14 and the sensor 45 move upward until the measuring medium L passes above the mounting portion 4. In this process, from the first state in which the measurement medium L of the sensor 45 is reflected on the side surface of the base 5 (in some cases, through the state in which the measurement medium L of the sensor 45 is reflected by the pin 6), the measurement medium L of the sensor 45 is reflected. Transitions to the second state, which cannot be reflected by the components of the mounting portion 4. Reflection at pin 6 is not particularly necessary. When the measuring medium L reaches the upper surface of the base 5, the transition from the first state to the second state occurs. In this example, the upper surface of the base 5 is the object to be measured.

Next, the controller 30 acquires the position zr1 in the Zr direction of the hand 14 when the object to be measured is measured by the sensor 45 (S43). This measurement position xr1 is derived from the detection result of the encoder 40. With reference to FIG. 17, in the first state and the second state, the input of the sensor 45 depends on the distance from the sensor 45 to the portion where the measurement medium L is reflected or the material of the portion where the measurement medium L is reflected. The properties (strength, etc.) of the measurement medium L input to the unit are different. The controller 30 identifies a point where the input result changes peculiarly, and determines that the measurement object (in this example, the upper surface of the base 5) has been measured at this change point. Then, the position of the hand 14 in the Zr direction at this time is acquired as the measurement position zr1.

Next, the controller 30 measures the position deviation amount Δz in the Zr direction based on the measurement position zr1 and the actual position z1 in the Z direction (S44). The "actual position" is the actual position of the object to be measured. The actual position z1 in the Z direction is the Z coordinate in the device coordinate system CS1 of the object to be measured.
With reference to FIGS. 16 and 17, in step S44, the position deviation amount Δz is measured based on the measurement position zr1 and the actual position z1 in the Z direction of the measurement target object. The difference between the two positions zr1 and z1 is the distance az in the Z direction (Zr direction parallel to this) from the origin of the current robot coordinate system CSr to the origin of the device coordinate system CS1. This distance az is the sum of the design value az0 and the amount of positional deviation Δz. The controller 30 measures the position deviation amount Δz by subtracting the design value az0 previously stored in the memory 32 as a part of the device design data 36 from the distance az.

As a result, the normal calibration process S40 is completed. Since the deviation amount Δz is measured, the controller 30 can correct the robot coordinate system CSr as designed even if there is an assembly error or an installation error. Therefore, the positional relationship of the robot coordinate system CSr with respect to the device coordinate system CS1 is as expected.
As described above, according to the present embodiment, the deviation amounts Δx, Δy, ΔΘ, Δz of the robot coordinate system CSr with respect to the device coordinate system CS1 are measured with a simple system 100 configuration by a simple operation of the robot 3. And the robot coordinate system CSr can be calibrated. Therefore, it is possible to support precise position control of the robot 3 during actual operation.

(Modification example)
Although the embodiments of the present invention have been described so far, the above configurations can be appropriately modified, added and / or deleted within the scope of the present invention.
FIG. 18 shows a deviation of the robot coordinate system according to the modified example with respect to the device coordinate system. In the above embodiment, the design value Θ0 of the angle around the Zr axis with respect to the device coordinate system CS1 of the robot coordinate system CSr0 is 0 degrees, but the design value Θ0 may be an angle other than 0 degrees. In this case, by executing the angle calibration process, the angle of the current robot coordinate system CSr with respect to the device coordinate system CS1 is measured. This angle is the sum of the design value Θ0 and the angle deviation amount ΔΘ. Therefore, even in this modification, the angle deviation amount ΔΘ can be derived.

In the above embodiment, in step S22, the arm 11 moves in one direction in the Xr direction, and the sensor 45 ejects the measurement medium L in the Yr direction orthogonal to the moving direction. This moving direction and ejection direction are examples and can be changed. The arm 11 may move in any one direction within the reference plane RS, and the sensor 45 may move in any one direction within the reference plane RS. In this case, the equation shown in FIG. 11 is converted into an equation that takes into consideration the inclination angle with respect to the Xr direction in the moving direction and the inclination angle with respect to the moving direction in the injection direction. If these inclination angles are known, the angle calibration process can be performed in the same manner as in the above embodiment according to the converted equation.

FIG. 19 shows a robot position calibration system 100A according to a modified example. In the above embodiment, the sensor 45 is provided on the arm 11 (hand 14) of the robot 3, and the measurement objects 51 and 52 are components of the mounting portion 4 installed in the work space 2. However, this arrangement is used. May be the other way around. In the modified example, the measurement objects 51A and 52A are provided on the arm 11 (hand 14) of the robot 3. The sensor 45A is provided in a device other than the arm 11 of the robot 3 (for example, the upper surface of the base 5 of the mounting portion 4) in the work space 2. Also in this case, by moving the arm 11, the sensor 45A moves relative to the measurement objects 51A and 52A. Therefore, the amount of deviation can be measured in the same manner as in the above embodiment.

In the above embodiment, the deviation amount is measured using the two measurement objects 51 and 52, which is the minimum number of measurement objects required for the measurement principle of the deviation amount. The amount of deviation may be measured based on the measurement results of three or more objects to be measured, and the final amount of deviation may be determined by statistically processing (average, etc.) a plurality of measurement results, thereby improving the measurement accuracy. do.
The sensor 45 may be provided not only in the hand 14 but also in other parts constituting the arm 11 of the robot 3. However, if the hand 14 is provided, the posture of the sensor 45 can be easily controlled, so that the ejection direction of the measuring medium L can be easily controlled.

The robot 3 may be a horizontal articulated robot having three or more links. The robot 3 may be another type of robot, such as a vertical articulated robot. The work handled by the robot 3 is not limited to the semiconductor wafer W, and the end effector of the robot 3 is not limited to the hand that grips the work. That is, the robot position calibration system 100 is also suitably applied to the robot 3 that performs work other than the transfer of the semiconductor wafer W.

1 Semiconductor manufacturing equipment 2 Work space 3 Robot 4 Mounting part 6 Pin 11 Arm 14 Hand 30 Controller 45 Sensor 51, 52 Measurement target 100 Robot position calibration system

Claims (7)

Two measurement objects provided on either the robot arm or the work space in which the robot is installed and separated from each other in the reference plane, and
A sensor provided on the other side of the arm and the work space to measure the two measurement objects, and a sensor.
A controller that drives and controls the arm of the robot,
Equipped with
The controller
By driving the arm, the sensor is relatively linearly moved in one direction in the reference plane with respect to the two measurement objects.
The sensor acquires the two positions of the arm in the one direction when each of the two measurement objects is measured.
The measurement distance in the one direction in the reference plane between the two measurement objects obtained from the acquired two positions and the actual distance in the reference plane between the two measurement objects are set. Based on this, the amount of angular deviation of the robot in the reference plane is measured.
Robot position calibration system. The sensor emits an ultrasonic or light measurement medium and measures the measurement object based on the reflection of the measurement medium on the measurement object.
When the sensor is moved relative to the measurement object, the controller moves the arm so that the ejection direction of the measurement medium is orthogonal to the movement direction of the arm in the reference plane. ,
The robot position calibration system according to claim 1. The controller
Correct the robot coordinate system so that the measured amount of angle deviation is offset.
By driving the arm while controlling the position of the arm in the corrected robot coordinate system, the sensor is moved relative to the two measurement objects.
The position of the arm when the sensor measures one of the two measurement objects is obtained.
The amount of positional deviation of the robot in the reference plane is measured based on the acquired position and the actual position of the object to be measured.
The robot position calibration system according to claim 1 or 2. The controller
By driving the arm, the sensor is moved relative to the two measurement objects in the normal direction of the reference plane.
Obtaining the position of the arm when the sensor measures any of the measurement objects,
The amount of positional deviation of the robot in the normal direction is measured based on the acquired position and the actual position of the object to be measured.
The robot position calibration system according to any one of claims 1 to 3. The sensor is attached to the arm, and the two measurement objects are provided in the work space.
The two measurement objects are components of the device installed in the work space.
The robot position calibration system according to any one of claims 1 to 4. Two measurement objects provided on either the robot arm or the work space in which the robot is installed and separated from each other in the reference plane, and
A robot position calibration method used in a robot position calibration system provided on the other side of the arm and the work space and comprising a sensor for measuring the two measurement objects.
By driving the arm, the sensor is relatively linearly moved in one direction in the reference plane with respect to the two measurement objects.
Acquiring the two positions of the arm in the one direction when the sensor measures each of the two measurement objects, and
The measurement distance in the one direction in the reference plane between the two measurement objects obtained from the acquired two positions and the actual distance in the reference plane between the two measurement objects are set. Based on this, measuring the amount of angular deviation of the robot in the reference plane, and
Robot position calibration method. A computer is made to execute the robot position calibration method according to claim 6.
Robot position calibration program.

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