ROBOT SYSTEM WITH DETERMINATION SYSTEM FOR ADDITIONAL MEASURING TECHNOLOGY POSITION COORDINATES

Abstract

Robot system that includes the following an articulated robot arm (110) which includes a first arm section (120) which is mounted on a first rotary joint (125) at a near end (PE1) of the first arm section (120), wherein the first rotary joint (125) has an axis of rotation (RA1) that is aligned along a z-axis direction, such that the first arm section (120) moves about the first rotary joint (125) in an xy-plane that is perpendicular to the z-axis, wherein the first arm section (120) has a second pivot connection (135) located at a remote end (DE1) of the first arm section (120), wherein the axis of rotation (RA2) of the second rotary joint (135) is essentially aligned along the z-axis direction; a second arm section (130) which is mounted on the second pivot point (135) at a near end (PE2) of the second arm section (130), such that the second arm section (130) moves about the second pivot point in an xy-plane which is substantially perpendicular to the z-axis; and a motion control system (140) configured to control an end tool position (ETP) of an end tool (ETL) with an accuracy level defined as robot accuracy, based at least partially on sensing and controlling the angular positions of the first and second arm sections (130) to control the first and second rotary joints, respectively, using position sensors (SEN1, SEN2) incorporated in the articulated robot (110); and a determination system (150) for additional measurement position coordinates, which in turn comprises the following a first image acquisition configuration (160) comprising a first camera (CAM1), wherein the first image acquisition configuration (160) has an optical axis (OA1) that is substantially parallel to the z-axis and has a focus area along its optical axis (OA1); an XY scale (170) comprising a substantially planar substrate (SUB) oriented substantially perpendicular to the z-axis and several corresponding mapping features (IIF, AIF) distributed on the substrate (SUB), wherein the corresponding mapping features (IIF, AIF) are located at corresponding known XY scale coordinates on the XY scale (170); an image trigger section (181) configured to input at least one input signal belonging to the end tool position (ETP) and to determine the time of a first image acquisition trigger signal based on the at least one input signal and to output the first image acquisition trigger signal to the first image acquisition configuration (160), wherein the first image acquisition configuration (160) is configured to acquire a digital image of the XY scale (170) at an image acquisition time in response to receiving the first image acquisition trigger signal, and a metrology position coordinate processing section (190) configured to input the captured image and to identify at least one corresponding mapping feature (IIF, AIF) of the XY scale (170) contained in the captured image and the associated corresponding known XY scale coordinate location, wherein the determination system (150) for additional measurement position coordinates is configured such that one movable element from the XY scale (170) or the first image acquisition configuration (160) is coupled to the second arm section (130) near the remote end (DE2) of the second arm section (130) and the other is coupled to a stationary element (STE), wherein the location of the XY scale (170) along the z-axis is within the focus area of ​​the first image acquisition configuration (160) and the stationary from the XY scale (170) or the first image acquisition configuration (160) defines a first reference position (REF1); the determination system (150) for additional metrology position coordinates is configured such that the metrology position coordinate processing section (190) is configured to determine a relative position between the movable from the XY scale (170) or the first image acquisition configuration (160) and the first reference position (REF1) with an accuracy level better than the robot accuracy, based on determining an image position of the identified at least one corresponding imageable feature (IIF, AIF) in the acquired image; and the specific relative position specifies the metrology position coordinates of the end tool position (ETP) at the time of image acquisition with an accuracy level that is better than the robot accuracy, at least for x and y metrology position coordinates in an xy plane that is perpendicular to the z-axis.

Description

BACKGROUND Technical area

[0001] This disclosure relates to robot systems and in particular to systems for determining the coordinates of an end tool position of an articulated robot. Description of the state of the art

[0002] Robotic systems are increasingly used in manufacturing and other processes. One type of articulated robot system widely used is a Selective Compliance Articulated Robot Arm (SCARA). Such SCARA systems typically have a base with a first arm section rotatably coupled to the base and a second arm section rotatably coupled to one end of the first arm section. In various configurations, an end tool may be coupled to one end of the second arm section (e.g., to perform specific work and / or inspection operations). These systems may include position sensors (e.g., rotary encoders) used to determine / control the positioning of the arm sections and, consequently, the positioning of the end tool.In various implementations, such systems can have a positioning accuracy of approximately 100 micrometers, limited by specific factors (e.g., the performance of the rotary encoder in combination with the mechanical stability of the robot system, etc.).

[0003] US Patent US 4,725,965 A (the “965 Patent”), incorporated herein in its entirety by reference, discloses specific calibration techniques for improving the accuracy of a SCARA system. As described in the 965 Patent, a technique is provided for calibrating a SCARA-type robot comprising a first rotatable arm section and a second rotatable arm section that guides an end tool. The calibration technique is related to the fact that the SCARA robot can be controlled using a kinematic model which, if accurate, allows the arm sections to be positioned in both a first and a second angular configuration, with the end tool, guided by the second arm section, remaining in the same position.To calibrate the kinematic model, the arm sections are positioned in a first configuration so that the end tool is located above a fixed reference point. Then, the arm sections are positioned in a second angular configuration so that the end tool is nominally aligned with the reference point again. The error in the kinematic model is calculated from the displacement of the end tool's position from the reference point when the arm sections are switched from the first to the second angular configuration. The kinematic model is then compensated for the calculated error. These steps are repeated until the error reaches zero, at which point the SCARA robot's kinematic model is considered calibrated.

[0004] As further described in the 1965 patent, the calibration technique may involve the use of special cameras. For example, in one implementation, the reference point may be the center of the field of view of a stationary television camera (i.e., located on the ground below the end tool), and the camera's output signal may be processed to determine the displacement of the end tool's position from the center of the camera's field of view when the joints are switched from the first configuration to the second configuration. In another implementation, the second arm section may guide a camera, and the technique may begin by placing the arm sections in a first angular configuration, at which point a second predetermined interior angle between the arm sections is measured to center the camera guided by the second arm section directly above a fixed reference point.The arm sections are then positioned in a second angular configuration, where an interior angle equal to the second predetermined interior angle is measured between the arm sections to nominally reposition the camera above the reference point. The camera's output signal is then processed to calculate the shift in the reference point's position, as seen by the camera, when switching the arm sections from the first to the second angular configuration. The error in the camera's known position is then determined in accordance with this shift in the reference point's position as seen by the camera. These steps are then repeated as part of the calibration process until the error approaches zero.

[0005] Although techniques like those described in the 1965 patent can be used to calibrate a SCARA robot system, in certain applications it may be less desirable to use such techniques (which, for example, may be time-consuming and / or may not provide the desired level of accuracy for all possible orientations of the SCARA robot during specific operations, etc.). A robot system that can provide improvements with regard to such problems (e.g., to increase the reliability, reproducibility, speed, etc., of position determination during workpiece measurements and other processes) would be desirable.

[0006] Furthermore, DE 10 2016 116 811 A1 discloses a system for determining the elastic deflection of robot components. In this system, a measuring mark, either attached to a robot link or externally, is detected by a camera before and after a change in the robot's position. A control unit calculates the actual deflection of the connecting piece from the displacement of the measuring mark's position. DE 32 41 510 A1 describes a method for robot control in which an optical pattern, such as a grid or laser beams, is projected into the workspace. A detector attached to the robot arm scans this pattern. The resulting signals serve as an external reference coordinate system, independent of the robot mechanics, for position control. US 2018 / 004 188 A1 describes a robot whose moving part performs an action based on the position of a first marker.In this process, the marker is captured by an imaging unit attached to the moving part in two different positions and orientations of the moving part. The marker's position is determined from the first and second images acquired, along with the corresponding robot coordinates, in order to control or calibrate the robot. US 2015 / 0025683A1 describes a calibration procedure for a robot system with a visual sensor. At least three teach points are used for hand-eye calibration. Markers at two of these points have the same inclination to the optical axis and lie in a plane perpendicular to it, while the third point has a different inclination. Based on the positions in the robot and image processing coordinate systems, a calibration value is calculated to reduce the influence of quantization errors along the optical axis.US 6,681,151 B1 describes a system for the visual servo control of a robot. An image processing system uses a search tool that detects trained reference marks on a workpiece held by the robot, even if these marks are transformed translationally and non-translatively. Based on the deviation between the detected and the desired position of the mark, the system calculates correction values ​​that are transformed into robot coordinates to iteratively guide the workpiece to the target position. US 5,297,238 A describes a method for calibrating a robot's tool coordinate system relative to a known reference frame. In this method, a sensor tool is attached to the robot and calibrated. Robot data is recorded at various positions through relative movement between the sensor tool and a calibration feature.Using coordinate transformations of this data, the correct pose of the TCF relative to the CRF is determined to compensate for robot inaccuracies. SUMMARY

[0007] The invention is based on the objective of providing a robot system that enables improved accuracy in determining the end tool position, particularly compared to the accuracy of conventional SCARA robots.

[0008] This problem is solved by a robot system with the features of claim 1, a method for operating a determination system for additional measurement position coordinates with the features of claim 13, and a determination system for additional measurement position coordinates for use with an articulated robot with the features of claim 20. Advantageous further developments and embodiments are specified in the dependent claims.

[0009] A robotic system is created that includes an articulated robot (e.g., a SCARA robot) and a system for additional measurement position coordinates. The articulated robot comprises a first and a second arm section, a first and a second rotary joint, a motion control system, and position sensors. The first arm section is mounted to the first rotary joint at a near end of the first arm section. The first rotary joint has an axis of rotation oriented along the z-axis, so that the first arm section moves around the first rotary joint in an xy-plane perpendicular to the z-axis. The second rotary joint is located at a far end of the first arm section. The second rotary joint has its axis of rotation nominally oriented along the z-axis. The second arm section is mounted to the second rotary joint at a near end of the second arm section.The second arm section moves around the second rotary joint in an xy-plane that is nominally perpendicular to the z-axis. The motion control system is configured to control the end-tool position of an end tool (e.g., a touch probe, a scanning probe, a camera, etc., as part of an end-tool configuration coupled near a remote end of the second arm section). The end-tool position is controlled with an accuracy level defined as robot accuracy, based at least in part on sensing and controlling the angular positions of the first and second arm sections around the first and second rotary joints, respectively, using the position sensors (e.g., rotary encoders) incorporated into the articulated robot.

[0010] The system for determining additional metrology position coordinates comprises a first image acquisition configuration, an XY scale, an image trigger section, and a metrology position coordinate processing section. The first image acquisition configuration includes a first camera and has an optical axis nominally aligned parallel to the z-axis and a focus area along the optical axis. The XY scale comprises a nominally planar substrate, nominally oriented perpendicular to the z-axis, and several corresponding mapping features distributed on the substrate. The corresponding mapping features are located at corresponding known XY scale coordinates on the XY scale.The image trigger section is configured to receive at least one input signal relating to the end tool position, determine the time of a first image acquisition trigger signal based on this input signal, and output the first image acquisition trigger signal to the first image acquisition configuration. The first image acquisition configuration is configured to acquire a digital image of the XY scale at an image acquisition time in response to receiving the first image acquisition trigger signal. The metrology position coordinate processing section is configured to input the acquired image and identify at least one corresponding mappingable feature of the XY scale contained in the acquired image and its associated known XY scale coordinate location. In various implementations, the XY scale can be incremental or absolute.

[0011] The system for determining additional measurement position coordinates is configured such that a movable coordinate from the XY scale or the first image acquisition configuration is coupled to the second arm section near its far end, with the location of the XY scale along the z-axis within the focus area of ​​the first image acquisition configuration. The stationary coordinate from the XY scale or the first image acquisition configuration defines a first reference position.The determination system for additional metrology position coordinates is further configured such that the metrology position coordinate processing section can be operated to determine a relative position between the movable position from the XY scale or the first image acquisition configuration and the first reference position with an accuracy level better than the robot accuracy, based on determining an image position of the identified at least one corresponding imageable feature in the acquired image. The determined relative position specifies the metrology position coordinates of the end tool position at the time of image acquisition with an accuracy level better than the robot accuracy, at least for x and y metrology position coordinates in an xy plane perpendicular to the z-axis.In various implementations, the determination system is configured for additional metrology position coordinates to determine the metrology position coordinates of the end tool position at the image acquisition time based on the determined relative position and a known coordinate position offset between the end tool position and the moving one from the XY scale or the first image acquisition configuration.

[0012] In various implementations, the XY scale can be coupled to the second arm segment near its far end. The first image acquisition configuration can be coupled to the stationary element. In various implementations, the stationary element can comprise a frame positioned above at least one section of the articulated robot's operational working volume. The first image acquisition configuration can be attached to the frame above a section of the articulated robot's operational working volume.

[0013] In various implementations, the robot system can operate in either a robot position coordinates mode or an additional metrology position coordinates mode. The robot position coordinates mode can correspond to an independent and / or standard operating mode for the articulated robot (e.g., an operating mode in which the articulated robot operates independently, such as when an additional metrology position coordinate determination system is not active or otherwise provided). In the robot position coordinates mode, the articulated robot movements and the corresponding end tool position are controlled and determined with the degree of accuracy defined as the robot accuracy (i.e., using the position sensors integrated into the articulated robot).Conversely, in the operating mode with additional metrology position coordinates, a relative position, which specifies the metrology position coordinates of the end tool position at an image acquisition time, can be determined by the additional metrology position coordinate determination system with an accuracy level better than the robot accuracy (e.g., better than the accuracy of the position sensors contained in the articulated robot), at least for x and y metrology position coordinates in an xy-plane perpendicular to the z-axis. In various implementations, the determined position information (e.g., the determined relative position, the determined metrology position coordinates of the end tool position, and / or other associated determined position information) can then be used to execute a defined function (e.g., as part of workpiece measurements, positioning control of the articulated robot, etc.).

[0014] As an example regarding the positioning control of the articulated robot during operation with additional metrology position coordinates, instead of using the position sensors integrated into the articulated robot to control the positioning of the end tool, an output from the determination system for additional metrology position coordinates can be fed back to the motion control system or used in some other way to control the positioning of the end tool. In various implementations, a hybrid operation can be implemented, whereby the position sensors integrated into the articulated robot can be used during an initial phase of the robot's motion (e.g., to determine / control the positions of the arm sections and the corresponding end tool position as part of initial / fast / coarse motion positioning).Then, during a second part of the robot movement time, instead of using the position sensors of the articulated robot, an output from the determination system for additional measurement position coordinates (e.g., the determined relative positioning or associated position information) can be fed back to the motion control system or used in other ways to control the positioning (e.g., to determine / control the positions of the arm sections and the corresponding end tool position as part of a more accurate final / slower / fine motion positioning). Brief description of the multiple views of the drawings Fig. Figure 1 is a block diagram of a first exemplary implementation of a robot system, which includes an articulated robot arm and a determination system for additional measurement position coordinates; Fig. Figure 2 is an isometric diagram of a second exemplary implementation of a robot system similar to the robot system of Fig. 1, in which a first image acquisition configuration is coupled with a stationary element; Fig. Figure 3 is an isometric diagram of a third exemplary implementation of a robot system in which an XY scale is coupled to a stationary element; Fig. Figure 4 is an isometric diagram of an exemplary implementation of an incremental XY scale; Fig. Figure 5 is an isometric diagram of an exemplary implementation of an absolute XY scale; Fig. 6A and Fig. 6B are flowcharts that illustrate exemplary implementations of routines for operating a robot system that includes an articulated robot arm and a system for determining additional measurement position coordinates; and Fig. Figure 7 is a flowchart that represents an exemplary implementation of a routine for determining an end tool position, in which position sensors can be used during a first section of a movement time and a certain relative position of a determination system can be used for additional measurement position coordinates during a second section of a movement time. DETAILED DESCRIPTION

[0015] Fig. Figure 1 is a block diagram of a first exemplary implementation of a robot system 100, which includes an articulated robot 110 and a determination system 150 for additional metrology position coordinates. The articulated robot 110 comprises a first and a second arm section 120 and 130, a first and a second rotary joint 125 and 135, position sensors SEN1 and SEN2, an end tool configuration ETCN, and a robot motion control and processing system 140. The first arm section 120 is mounted on the first rotary joint 125 at a near end PE1 of the first arm section 120. The first rotary joint 125 (which is located, for example, at an upper end of a supporting base section BSE) has a rotation axis RA1 that is aligned along a z-axis direction, so that the first arm section 120 moves about the first rotary joint 125 in an xy-plane that is perpendicular to the z-axis.The second rotary joint 135 is located at a distant end DE1 of the first arm section 120. The second rotary joint 135 has its axis of rotation RA2 nominally aligned along the z-axis. The second arm section 130 is mounted to the second rotary joint 135 at a near end PE2 of the second arm section 130, such that the second arm section 130 moves around the second rotary joint 135 in an xy-plane that is nominally perpendicular to the z-axis. In various implementations, the position sensors SEN1 and SEN2 (e.g., the rotary encoders) can be used to determine the angular positions (e.g., in the xy-plane) of the first and second arm sections 120 and 130 around the first and second rotary joints 125 and 135, respectively.

[0016] In various implementations, the end tool configuration ETCN can include a Z-movement mechanism ZMM, a Z-arm section ZARM, a position sensor SEN3, and an end tool coupling section ETCP that couples to an end tool ETL. In other implementations, the end tool ETL can include an end tool scanning section ETSN and an end tool probe ETST with a contact point CP (e.g., for contacting a workpiece surface WP). The Z-movement mechanism ZMM is located near the remote end DE2 of the second arm section 130. The Z-movement mechanism ZMM (e.g., a linear actuator) is configured to move the Z-arm section ZARM up and down in the z-axis direction. In some implementations, the Z-arm section ZARM can also be configured to rotate about an axis parallel to the z-axis direction.In any case, the end tool ETL is coupled to the end tool coupling section ETCP and has a corresponding end tool position ETP with corresponding coordinates (e.g., x, y, and z coordinates). In various implementations, the end tool position ETP can correspond to or be close to the remote end DE3 of the Z-arm section ZARM (e.g., at or near the end tool coupling section ETCP).

[0017] The motion control system 140 is configured to control the end tool position ETP of the end tool ETL with an accuracy level defined as robot accuracy. Specifically, the motion control system 140 is generally configured to control the x and y coordinates of the end tool position ETP with robot accuracy based at least partially on sensing and controlling the angular positions (i.e., in the xy-plane) of the first and second arm sections 120 and 130 around the first and second rotary joints 125 and 135, respectively, using the position sensors SEN1 and SEN2. In various implementations, the motion control and processing system 140 may include a first and a second rotary joint control and sensing section 141 and 1412, respectively, which can receive signals from the position sensors SEN1 and SEN2 for sensing the angular positions of the first and second arm sections 120 and 130 and / or control signals (e.g.,(for motors etc.) in the first and second rotary joint 125 and 135 to rotate the first and second arm section 120 and 130.

[0018] Additionally, the motion control system 140 is generally configured to control the z-coordinate of the end tool position ETP with robot accuracy based at least partially on sensing and controlling the linear position (i.e., along the z-axis) of the Z-arm section ZARM using the Z-motion mechanism ZMM and the position sensor SEN3. In various implementations, the motion control and processing system 140 can include a Z-motion mechanism control and sensing section 143, which can receive signals from the position sensor SEN3 to sensing the linear position of the Z-arm section ZARM or provide control signals to the Z-motion mechanism ZMM (e.g., a linear actuator) to control the Z-position of the Z-arm section ZARM.

[0019] The Motion Control and Processing System 140 can also receive signals from the End Tool Sensing Section ETSN. In various implementations, the End Tool Sensing Section ETSN can include a circuit arrangement and / or configurations that are part of the End Tool ETL's operations for probing a workpiece WP. As described in more detail below, in various implementations, the End Tool ETL (e.g., a touch probe, a scanning probe, a camera, etc.) can be used to contact or otherwise detect surface locations / positions / points on a workpiece WP, for which various corresponding signals can be received, determined, and / or processed by the End Tool Sensing Section ETSN, and which can provide the corresponding signals to the Motion Control and Processing System 140.In various implementations, the motion control and processing system 140 can include an end tool control and sensing section 144, which can provide control signals to the end tool scanning section ETSN and / or receive scanning signals from it. In various implementations, the end tool control and sensing section 144 and the end tool scanning section ETSN can be combined and / or indistinguishable.In various implementations, the first and second rotary joint control and sensing sections 141 and 142, the Z-movement mechanism control and sensing section 143, and the end tool control and sensing section 144 can all provide outputs to and / or receive control signals from a robot position processing section 145, which can control and / or determine the overall positioning of the articulated robot 110 and corresponding end tool position ETP as part of the robot motion control and processing system 140.

[0020] In various implementations, the determination system 150 for additional metrology position coordinates can be included in the articulated robot or added to it in another way (e.g., as part of a retrofit configuration that can be added to an existing articulated robot 110, etc.). In general, the determination system 150 for additional metrology position coordinates can be used to provide an improved degree of accuracy for determining the end tool position (ETP). In particular, as described in more detail below, the determination system 150 for additional metrology position coordinates can be used to determine a relative position that specifies the metrology position coordinates of the end tool position (ETP) with a degree of accuracy better than the robot accuracy, at least for the x and y metrology position coordinates in an xy plane perpendicular to the z-axis.

[0021] As in Fig. As shown in Figure 1, the determination system 150 for additional measurement position coordinates comprises a first image acquisition configuration 160, an XY scale 170, an image trigger section 181, and a measurement position coordinate processing section 190. The first image acquisition configuration 160 is coupled to a stationary element STE. In various implementations, the stationary element STE can comprise a frame located above at least one section of an operational working volume OPV of the articulated robot 110, and the first image acquisition configuration 160 is attached to the frame above a section of the operational working volume OPV. In various implementations, the stationary element STE can include one or more structural support elements SSP (extending, for example, from a floor, ceiling, etc.) for holding the stationary element STE in a fixed location (e.g.,(with a fixed position and / or orientation) relative to the articulated robot 110.

[0022] The first image acquisition configuration 160 includes a first camera CAM1 and has an optical axis OA1 that is nominally aligned parallel to the z-axis. The first image acquisition configuration 160 has an effective focus range REFP along its optical axis OA1. In various implementations, the range REFP may be limited by a first and a second effective focus position EFP1 and EFP2, as described in more detail below. At any given time, the first image acquisition configuration 160 has an effective focus position EFP that falls within the range REFP. In an implementation using a variable focal length (VFL) lens, the range REFP may correspond to the focal length range of the VFL lens.

[0023] In various implementations, a VFL lens used can be a lens with an adjustable acoustic gradient refractive index (TAG lens). Regarding the general operations of such a TAG lens, in various implementations, a lens control unit (such as that included in the first image acquisition configuration and image processing section 180) can periodically and rapidly adjust or modulate the optical power of the TAG lens to achieve a high-speed TAG lens capable of periodic modulation (i.e., with a TAG lens resonant frequency) of 250 kHz, 70 kHz, 30 kHz, or the like. In such a configuration, the effective focus position (EFP) of the first image acquisition configuration 160 can be moved (rapidly) within the range (REFP) (e.g., an autofocus search range).The effective focus position EFP1 (or EFPmax) can correspond to the maximum optical power of the TAG lens, and the effective focus position EFP2 (or EFPmin) can correspond to the maximum negative optical power of the TAG lens. In some implementations, the midpoint of the REFP range may be labeled EFPnom and may correspond to zero optical power of the TAG lens.

[0024] In various implementations, such a VFL lens (e.g., a TAG lens) and a corresponding REFP area can be advantageously chosen so that the configuration limits or eliminates the need for macroscopic mechanical adjustments of the first image acquisition configuration 160 and / or adjustments of distances between components to change the effective focus position EFP. For example, in an implementation where an unknown magnitude of tilt or "sag" may occur at the far end DE2 of the second arm section 130 (e.g., due to the weight and / or specific orientations of the first and second arm sections 120 and 130, etc.), the precise focus distance from the first image acquisition configuration 160 to the XY scale 170 may be unknown and / or may vary with different orientations of the arms, etc.In such a configuration, it may be desirable to use a VFL lens that can scan or otherwise adjust the effective focus position EFP in order to determine the XY scale 170 and focus precisely on it.

[0025] In various implementations, the XY scale 170 comprises a nominally planar substrate SUB, nominally oriented perpendicular to the z-axis, and several corresponding mapping features distributed across the substrate SUB. The corresponding mapping features are located at known x- and y-scale coordinates on the XY scale 170. In different implementations, the XY scale 170 can be an incremental or absolute scale, as shown below with reference to the Fig. 4 and Fig. 5 is described in more detail.

[0026] In various implementations, the image trigger section 181 and / or the metrology position coordinate processing section 190 can be included as part of an external control system (ECS) (e.g., as part of an external computer, etc.). The image trigger section 181 can be included as part of a first image acquisition configuration and processing section 180. In various implementations, the image trigger section 181 is configured to input at least one input signal belonging to the end tool position (ETP), determine the time of a first image acquisition trigger signal based on the at least one input signal, and output the first image acquisition trigger signal to the first image acquisition configuration 160. In various implementations, the first image acquisition configuration 160 is configured to acquire a digital image of the XY scale 170 at an image acquisition time in response to receiving the first image acquisition trigger signal.In various implementations, the metrology position coordinate processing section 190 is configured to input the captured image and identify at least one corresponding mappable feature of the XY scale 170 contained in the captured image and its associated known XY scale coordinate location. In various implementations, the external control system ECS may also include a section 147 for standard operating mode with robot position coordinates and a section 192 for operating mode with additional metrology position coordinates to implement corresponding operating modes, as described in more detail below.

[0027] In various implementations, the first image acquisition configuration 160 can include a component (e.g., a sub-circuit, routine, etc.) that periodically activates image integration from camera CAM1 (e.g., at a set time interval). The first image acquisition trigger signal can activate a stroboscopic light duration or another mechanism to effectively freeze motion and thus determine an exposure within the integration time interval. In such implementations, if no first image acquisition trigger signal is received during an integration interval, the resulting image can be discarded. Conversely, if a first image acquisition trigger signal is received during the integration interval, the resulting image can be stored and / or otherwise processed / analyzed to determine a relative position, as described in more detail below.

[0028] In different implementations, different types of end tools can provide different types of outputs to ETL that can be used with respect to image trigger section 181. For example, in an implementation where the end tool ETL is a touch probe used to measure a workpiece and which outputs a touch signal when it touches the workpiece, image trigger section 181 can be configured to input this touch signal, or a signal derived from it, as the at least one input signal on which the timing of an initial image acquisition trigger signal is based.As another example, in an implementation where the end tool ETL is a scanning probe used to measure a workpiece and provides the corresponding workpiece measurement sample data corresponding to a sample time signal, the image trigger section 181 can be configured to input this corresponding sample time signal or a signal derived from it as the at least one input signal. As another example, in an implementation where the end tool ETL is a camera used to provide a corresponding workpiece measurement image corresponding to a corresponding workpiece image acquisition signal, the image trigger section 181 can be configured to input this workpiece image acquisition signal or a signal derived from it as the at least one input signal.

[0029] In the example implementation of Fig. 1. The determination system 150 for additional measurement position coordinates is configured such that the XY scale 170 is coupled to the second arm section 130 near the far end DE2 of the second arm section 130, and the first image acquisition configuration 160 is coupled to a stationary element STE (e.g., a frame located above the articulated robot 110) and defines a first reference position REF1. In an alternative implementation (such as that described below with reference to Fig. 3 (as described in more detail) a determination system for additional measurement position coordinates can be configured such that the first image acquisition configuration 160 is coupled with the second arm section 130 near the remote end DE2 of the second arm section 130 and the XY scale 170 is coupled with a stationary element STE and defines a first reference position REF1.

[0030] In any case, as described in more detail below, the location of the XY scale 170 along the z-axis is within the focus area of ​​the first image acquisition configuration 160 (for which, for example, the focus position can be set by a VFL lens or in another way), and the determination system 150 for additional metrology position coordinates is configured such that the metrology position coordinate processing section 190 can be operated to determine a relative position (which, for example, contains x and y coordinates) between the movable from the XY scale 170 or the first image acquisition configuration 160 and the first reference position REF1 with an accuracy level that is better than the robot accuracy, based on determining an image position of the identified at least one corresponding imageable feature in the acquired image.The determined relative position specifies the metrological position coordinates of the end tool position ETP at image acquisition time with an accuracy better than the robot accuracy, at least for x and y metrological position coordinates in an xy-plane perpendicular to the z-axis. In various implementations, the determination system 150 can be configured for additional metrological position coordinates to determine the metrological position coordinates of the end tool position ETP at image acquisition time based on the determined relative position and a known coordinate position offset (x and y coordinate offset) between the end tool position ETP and the moving position from the XY scale 170 or the first image acquisition configuration 160. It is understood that such a system can have particular advantages over various alternative systems.For example, in various implementations, a system like the one disclosed here may be smaller and / or less expensive than alternative systems that use technologies such as laser trackers or image measurement to track robot movement / positions, and in some implementations, it may also exhibit higher accuracy. Furthermore, the disclosed system does not consume or obscure any part of the operational work volume (OPV) as alternative systems might, for example, incorporate a scale or reference point on the floor or the worktable, or elsewhere in the same area (e.g., the operational work volume) where workpieces would otherwise be machined or inspected, etc.

[0031] Fig. Figure 2 is an isometric diagram of a second exemplary implementation of a robot system 200 similar to the robot system 100 from Fig. 1, in which the first image acquisition configuration 160 with a stationary element STE (e.g. the stationary element STE of Fig. 1) is coupled. It should be understood that special numbered components (e.g., 1XX or 2XX) of Fig. 2 identical or similarly numbered counterparts (e.g. 1XX) of Fig. 1. correspond to and / or have similar operations to them and can be understood as being similar or identical to them, and can otherwise be understood by analogy to them and as otherwise described below. This numbering scheme for indicating elements that have an analogous and / or identical construction and / or function is also applied to the following Fig. 3-5 applied.

[0032] In the configuration of Fig. 2 (i.e., similar to the configuration of Fig. 1) The XY scale 170 is coupled to the second arm segment 130 near the distant end DE2 of the second arm segment 130. In various implementations, as above with reference to Fig. As described in Figure 1, the stationary element STE, to which the first image acquisition configuration 160 is coupled, comprises a frame positioned above the articulated robot 110. Different implementations may define various reference axes and lines for referencing specific movements, coordinates, and angles of the components of the articulated robot 110. For example, the first and second arm sections 120 and 130 may each have defined horizontal centerlines CL1 and CL2, respectively, passing through the centers of the respective arm sections. An angle A1 may be defined such that it occurs between the centerline CL1 of the first arm section 120 and an xz-plane (e.g., corresponding to a magnitude of rotation of the first rotary joint 125 about the first axis of rotation RA1).An angle A2 can be defined such that it occurs between the horizontal centerline CL1 of the first arm section 120 and the horizontal centerline CL2 of the second arm section 130 (e.g. in accordance with a magnitude of rotation of the second pivot joint 135 about the second axis of rotation RA2).

[0033] In various implementations, the end tool configuration ETCN can be coupled to the second arm section 130 near the remote end DE2 of the second arm section 130 and can be configured to have an end tool axis EA of the end tool ETL that nominally intersects the centerline CL2 of the second arm section 130, and for which the end tool axis EA can generally be assumed to be parallel to the rotary axis RA2 and the z-axis. In various implementations, the end tool axis EA passes through the end tool position ETP and has a known coordinate position offset (i.e., for the x and y coordinates) from the XY scale 170. Accordingly, a known coordinate position offset can exist between the end tool position ETP and the XY scale 170. For example, the XY scale 170 can have a defined reference point (e.g.,in the center or at the edge of the XY scale 170), which has a known coordinate position offset (e.g., a known distance) in an xy-plane from the end tool axis EA and, accordingly, from the end tool position ETP. In various implementations, such a known coordinate position offset can be expressed as a known x-offset and a known y-offset. In various implementations, the known coordinate position offset between the end tool position ETP and the XY scale 170 can be used as part of the process for determining the metrology position coordinates of the end tool position ETP. In particular, as mentioned above, the determination system 150 for additional metrology position coordinates can be configured such that the metrology position coordinate processing section 190 operates to determine a relative position between the XY scale 170 and the first reference position REF1 (i.e.,as defined by the stationary first image acquisition configuration 160) based on determining an image position of the identified at least one corresponding imageable feature (i.e., the XY scale 170) in the acquired image. The determination system 150 for additional metrology position coordinates can further be configured to determine the metrology position coordinates of the end tool position ETP based on the determined relative position and a known coordinate position offset between the end tool position ETP and the movable XY scale 170. In a specific example implementation, the known coordinate position offset (e.g., expressed as a known x-offset and a known y-offset) can be added to or otherwise combined with the determined relative position to determine the metrology position coordinates of the end tool position ETP.

[0034] As a specific example of position coordinate configuration, the XY scale 170 can be set to have a reference position (e.g., an origin location) at X0, Y0, Z0 (which, for example, can have the values ​​0,0,0 for an origin location). In such a configuration, the reference location REF1 (i.e., as defined by the stationary first image acquisition configuration 160) can be at relative coordinates X1, Y1, Z1, and the center of a corresponding field of view FOV1 (corresponding, for example, to a captured image) can be at relative coordinates X1, Y1, Z0. A location of the end tool axis EA in an xy-plane extending from the XY scale 170 can be set to have relative coordinates X2, Y2, Z0. The end tool position ETP can be set to have coordinates X2, Y2, Z2. In various implementations, the end tool ETL can have a contact point CP (e.g.,at the end of an end tool probe ETST for contacting a workpiece) which can be defined such that it has the coordinates X3, Y3, Z3. In an implementation where the contact point CP of the end tool ETL does not vary in the x or y direction relative to the rest of the end tool, the X3 and Y3 coordinates can be the same as the X2 and Y2 coordinates, respectively.

[0035] In a specific example implementation, a captured image can be analyzed by the metrology position coordinate processing section 190 to determine a relative position (e.g., to determine the X1, Y1 coordinates corresponding to the center of the field of view FOV1 of the stationary first image acquisition configuration 160). Such a determination can be made in accordance with standard camera / scale image processing techniques (e.g., to determine the camera's position relative to the scale). Several examples of such techniques are described in US patents US 6,781,694 A; US 6,937,349 A; US 5,798,947 A; US 6,222,940 A; and US 6,640,008 A, each of which is fully incorporated by reference. In various implementations, such techniques can be used to determine the location of a field of view (such as the position of a camera) within a scale range (e.g.,within the XY scale (170), as below with reference to the . Fig. 4 and Fig. 5 is described in more detail. In various implementations, such a determination can involve identifying at least one corresponding imageable feature of the XY scale contained in the acquired image 170 and the associated corresponding known XY scale coordinate location. Such a determination can correspond to determining a relative position between the XY scale 170 and the first reference position REF1 (i.e., as defined by the stationary first image acquisition configuration 160). The relative X2, Y2 coordinates (i.e., the end tool position ETP) can then be determined according to the known coordinate position offset between the end tool position ETP and the XY scale 170 (e.g., adding the x and y position offset values ​​to X1 and Y1 to determine X2 and Y2).

[0036] In various implementations, the determination system 150 for additional measurement position coordinates can also include one or more additional image acquisition configurations. For example, as in Fig. As shown in Figure 2, the determination system 150 for additional metrology position coordinates includes a second image acquisition configuration 160', which has a second camera CAM2 and an optical axis OA2 that is nominally aligned parallel to the z-axis. The second image acquisition configuration 160' can determine a second reference position REF2 (which, for example, has relative coordinates X1', Y1', and Z1). The second image acquisition configuration 160' can have an effective focus area REFP along its optical axis OA2. In such a configuration, the image trigger section 181 can further be configured to input at least one input signal belonging to the end tool position ETP and to determine the time of a second image acquisition trigger signal based on the at least one input signal and to output the second image acquisition trigger signal to the second image acquisition configuration 160'.In various implementations, the second image acquisition configuration 160' can be configured to acquire a digital image of the XY scale 170 at an image acquisition time in response to receiving the second image acquisition trigger signal. The measurement position coordinate processing section 190 can further be configured to input the acquired image and identify at least one corresponding imageable feature of the XY scale 170 contained in the acquired image and the associated corresponding known XY scale coordinate location.

[0037] In various implementations, the metrology position coordinate processing section 190 can be operated to determine a relative position between the XY scale 170 and the second reference position REF2 with an accuracy better than the robot accuracy, based on determining an image position of the identified at least one corresponding imageable feature in the acquired image. In such an implementation, the determined relative position specifies the metrology position coordinates of the end tool position ETP at image acquisition time with an accuracy better than the robot accuracy, at least for x and y metrology position coordinates in an xy plane perpendicular to the z-axis.

[0038] In various implementations, the at least one input signal fed into the image trigger section 181 contains one or more signals derived from the motion control system 140. In such configurations, the image trigger section 181 can be configured to determine whether the XY scale 170 is aligned with the first or second image acquisition configuration 160 or 160', based on the one or more signals derived from the motion control system 140. If it is determined that the XY scale 170 is aligned with the first image acquisition configuration 160 (such that, for example, a sufficient portion of the XY scale 170 is captured by the first image acquisition configuration 160), the image trigger section 181 is configured to output the first image acquisition trigger signal. Conversely, if it is determined that the XY scale 170 is aligned with the second image acquisition configuration 160' (such that, for example,(a sufficient section of the XY scale 170 is captured by the second image acquisition configuration 160'), the image trigger section 181 is configured to output the second image acquisition trigger signal.

[0039] Fig. Figure 3 is an isometric diagram of a third exemplary implementation of a robot system 300, in which the XY scale 170 is coupled to the stationary element STE and defines the first reference position REF1. In the configuration of Fig. In Figure 3, the first image acquisition configuration 160 is coupled to the second arm section 130 near the remote end DE2 of the second arm section 130. In various implementations, the end tool axis EA has a known coordinate position offset (i.e., for the x and y coordinates) relative to the first image acquisition configuration 160. Accordingly, a known coordinate position offset can exist between the end tool position ETP and the first image acquisition configuration 160. For example, the first image acquisition configuration 160 can have a defined reference point (e.g., at a center point of the first image acquisition configuration 160) that has a known coordinate position offset (e.g., a known distance) in an xy-plane from the end tool axis EA and, consequently, from the end tool position ETP.In various implementations, such a known coordinate position offset can be expressed as a known x-offset and a known y-offset.

[0040] In various implementations, the known coordinate position offset between the end tool position ETP and the first image acquisition configuration 160 can be used as part of the process for determining the metrology position coordinates of the end tool position ETP. In particular, as mentioned above, the determination system 150 for additional metrology position coordinates can be configured such that the metrology position coordinate processing section 190 operates to determine a relative position between the first image acquisition configuration 160 and the first reference position REF1 (i.e., as defined by the stationary first XY scale 170) based on determining an image position of an identified at least one corresponding imageable feature (i.e., the XY scale 170) in the acquired image.The determination system 150 for additional metrology position coordinates can further be configured to determine the metrology position coordinates of the end tool position ETP based on the determined relative position and a known coordinate position offset between the end tool position ETP and the moving first image acquisition configuration 160. In a specific example implementation, the known coordinate position offset (e.g., expressed as a known x-offset and a known y-offset) can be added to or otherwise combined with the determined relative position to determine the metrology position coordinates of the end tool position ETP.

[0041] As a specific example of position coordinate configuration, the XY scale 170 can be set to have a reference location REF1 (e.g., an origin location) at X0, Y0, Z0 (which, for example, can have the values ​​0,0,0 for an origin location). The first image acquisition configuration 160 can be at a location with the relative coordinates X1, Y1, Z1, and the center of a corresponding field of view FOV1 (as captured, for example, in a captured image) can be at the relative coordinates X1, Y1, Z0. A location of the end tool axis EA in an xy-plane extending from the first image acquisition configuration 160 can be set to have the relative coordinates X2, Y2, Z1. The end tool position ETP can be set to have the coordinates X2, Y2, Z2. In various implementations, the end tool ETL can have a contact point CP (e.g.,at the end of a tool probe ETST for contacting a workpiece) which can be defined to have the coordinates X3, Y3, Z3. In an implementation where the contact point CP of the tool ETL does not vary in the x or y direction relative to the rest of the tool, the X3 and Y3 coordinates can be the same as the X2 and Y2 coordinates, respectively.

[0042] The robot system 300 can be implemented in various ways. Fig. 3 specific different design considerations and aspects compared to the robot system 200 from Fig. 2 exhibit (which relate, for example, to a possible vertical displacement or sagging at the remote ends DE1 and DE2 of the first and second arm sections 120 and 130, respectively). In an implementation where such displacement or sagging can occur (e.g., due to the weight and / or different orientations of the arm sections, image acquisition configuration 160, etc.), a particularly undesirable effect can occur in the robot system 300. Fig. 3. This is obtained with respect to the fact that the field of view (FOV) of the first image acquisition configuration 160 is shifted accordingly. In particular, such a vertical displacement or sag can cause a relatively significant shift / change in the location of the field of view (FOV) on the XY scale 170 (i.e., as it is attached to the stationary element STE), which can lead to a relatively significant error in the determined relative position and the corresponding metrology position coordinates of the end tool position (ETP). Due to such problems, in specific implementations, the configuration of the robot system 200 may be Fig. 2 can be viewed in such a way that they offer the corresponding advantages over the robot system 300 from Fig. 3.

[0043] Fig. Figure 4 is an isometric diagram of an exemplary implementation of an incremental XY scale 170A. As shown in Fig. As shown in Figure 4, the incremental XY scale 170A contains a group of uniformly spaced incremental mapping features (IIF). In various implementations, the incremental XY scale 170A can have a periodicity less than 100 micrometers (for example, the periodic spacings XSP1 and YSP1 between the incremental mapping features IIF along the corresponding x- and y-axes can each be less than 100 micrometers). In various implementations, the position information determined using the incremental XY scale 170A can have an accuracy of at least 10 micrometers. In contrast to robot accuracy, which in specific implementations can be approximately 100 micrometers, the accuracy determined using such an XY scale 170A can be at least 10 times that of the robot accuracy.In a specific example implementation, the incremental XY scale 170A can exhibit an even higher periodicity of approximately 10 micrometers, for which, if the magnification of the initial image acquisition configuration 160 is approximately 1x and interpolation is performed by a factor of 10x, an accuracy of about 1 micrometer can be achieved. Such a configuration would represent an improvement in accuracy of approximately 100x compared to a robotic accuracy of approximately 100 micrometers.

[0044] In various implementations, the location of the field of view (FOV) of the first image acquisition configuration 160 within the incremental XY scale 170A can provide a relative position between the XY scale 170A and the first reference position REF1. In various implementations, the first image acquisition configuration 160, in combination with the incremental XY scale 170A, can be used as part of a camera / scale image processing configuration. For example, the metrology position coordinate processing section 190 can determine a relative incremental position between the XY scale 170A and the first reference position REF1 based on the location of the field of view (FOV) within the incremental XY scale 170A, as specified by the section of the XY scale 170A in the acquired image. This is known in the art for camera / scale image processing techniques (e.g., as described in the references cited above).In different implementations, the incremental XY scale 170A can be of different sizes relative to the field of view (FOV) (e.g., the incremental XY scale 170A can be at least 4x, 10x, 20x, etc. larger than the field of view FOV).

[0045] In various implementations, the incremental position indicated by the XY scale 170A can be combined with position information from the articulated robot 110 to determine a relatively precise and / or absolute position. For example, the sensors SEN1 and SEN2 (e.g., rotary encoders) of the articulated robot 110 can indicate the end tool position ETP with the robot accuracy, for which the incremental position indicated by the XY scale 170A can be used to further refine the determined end tool position ETP, so that it has an accuracy better than the robot accuracy.In such a configuration, the metrology position coordinate processing section 190 can be configured to identify one or more corresponding imageable features IIF of the XY scale 170A contained in the captured image, based on the image positions of the one or more imageable features IFF in the captured image and based on position data of the articulated robot derived from the motion control system 140 according to the image acquisition time.

[0046] In such configurations, the corresponding mapping features IFF of the XY scale 170A can contain a set of similar mapping features IFF distributed on the substrate such that they are spaced at regular intervals by a distance greater than the maximum positional error allowed within the robot's accuracy. As in Fig. As shown in Figure 4, the mapping features IFF are spaced more than a maximum position error MPE, as defined by a circle representing a representative mapping feature IFF (e.g., at distances XSP1 and SSP1). It is understood that in such a configuration, the robot's position accuracy is sufficient to determine the location with an accuracy greater than the spacing between the mapping features IFF. In particular, in various implementations, a single mapping feature IFF on the XY scale 170A (i.e.,(where the mapping features are all located at known x and y metrology position coordinates on the XY scale 170A according to the uniform spacing across the scale) and are thus identified with sufficient accuracy by the position data of the articulated robot so that no two mapping features IFF can be confused with each other. In such a configuration, the location of each mapping feature IFF in the captured image can be used to further refine the end tool position ETP, so that it has an accuracy better than the robot accuracy, at least for x and y metrology position coordinates of the end tool position ETP in an xy-plane perpendicular to the z-axis.

[0047] As above with reference to Fig. As described in section 2, in a specific example implementation, the XY scale 170A can be set to have a reference position (e.g., an origin location) at X0, Y0, Z0 (which, for example, can have the values ​​0,0,0 for an origin location). In such a configuration, the reference location REF1 (i.e., as defined by the stationary first image acquisition configuration 160) can be at relative coordinates X1, Y1, Z1, and the center of a corresponding field of view FOV (as captured, for example, in a captured image) can be at relative coordinates X1, Y1, Z0. A location of the end tool axis EA in an xy-plane extending from the XY scale 170 can be set to have relative coordinates X2, Y2, Z0. The end tool position ETP can be set to have coordinates X2, Y2, Z2.

[0048] During operation, a captured image can be analyzed by the measurement position coordinate processing section 190 to determine the X1, Y1 coordinates corresponding to the center of the field of view (FOV1) of the stationary first image acquisition configuration 160. In various implementations, such a determination can be made in accordance with standard camera / scale image processing techniques for determining the location of a field of view (corresponding, for example, to a camera position) within a scale range (e.g., within the XY scale 170A). It should be understood that, in accordance with standard camera / scale image processing techniques, it is not necessary for the reference position / origin location X0, Y0, Z0 to be within the field of view (FOV) for such a determination to be made.The relative position can be determined from the scale information at any location along the XY scale 170A, as partially provided by the scale elements comprising the uniformly spaced incremental mapping features (IIF). In various implementations, such a determination may involve identifying at least one corresponding mapping feature of the XY scale 170 contained in the acquired image and its associated known XY scale coordinate location. Such a determination may be equivalent to determining a relative position between the XY scale 170 and the first reference position REF1 (i.e., as defined by the stationary first image acquisition configuration 160). The relative X2, Y2 coordinates (i.e., the end tool position ETP) can then be determined according to the known coordinate position offset between the end tool position ETP and the XY scale 170 (e.g.,(Add the x and y position offset values ​​to X1 and Y1 to determine X2 and Y2).

[0049] A specific illustrative example of combining the position information from the articulated robot 110 with the incremental position information provided by the XY scale 170A to determine a relatively precise and / or absolute position is as follows. As shown in Fig. As shown in Figure 4, the captured image can indicate that the center of the field of view (FOV) is in the middle of four incremental mapping features (IIF), but it cannot indicate which specific four incremental mapping features (IIF) of the XY scale 170 are included in the image. The position information from the articulated robot 110 can be accurate enough to provide such information for which the specific four incremental mapping features (IIF) of the XY scale 170A can be identified (e.g., partly based on the principles mentioned above, whereby the mapping features (IFF) are spaced by more than a maximum position error, as represented by a representative circular area (MPE), so that each mapping feature (IFF) can be uniquely identified).The captured image can then be analyzed by the metrology position coordinate processing section 190 to precisely determine where the center of the field of view (i.e., at coordinates X1, Y1, Z0) occurs within this subsection of the XY scale (i.e., containing the specific four incremental mapping features IIF). The process can then proceed as described above (e.g., to appropriately determine the X2 and Y2 coordinates of the end tool position ETP).

[0050] Fig. Figure 5 is an isometric diagram of an exemplary implementation of an absolute XY scale 170B. In the example of Fig. 5, similar to the incremental XY scale 170A, contains the absolute XY scale 170B, a group of uniformly spaced incremental mapping features (IIF), and also contains a set of absolute mapping features (AIF) that have uniquely identifiable structures (e.g., a 16-bit structure). In operation, a location of a field of view (FOV) of the first image acquisition configuration 160 within the absolute XY scale 170B (i.e., as it is contained in a captured image) provides an indication of an absolute position between the XY scale 170B and the first reference position (REF1). In the implementation of Fig. 5. The set of absolute mapping features (AIF) on the substrate SUB is distributed such that they are spaced less than a distance corresponding to a distance across a field of view (FOV) of the first image acquisition configuration 160 (e.g., at intervals XSP2 and YSP2) (i.e., such that at least one mapping feature AIF will always be contained within a field of view). In operation, the metrology position coordinate processing section 190 is configured to identify at least one corresponding absolute mapping feature AIF contained in the captured image of the XY scale 170B, based on the uniquely identifiable structure of the corresponding absolute mapping feature AIF.It is to be understood that such implementations are capable of independently determining an absolute position, which specifies the end tool position ETP, with an accuracy better than the robot accuracy, at least for the x and y metrology position coordinates of the end tool position ETP in an xy plane perpendicular to the z axis (and which, for example, unlike the incremental XY scale 170B, does not require combining with position information from the articulated robot 110 to determine the absolute position).

[0051] A specific illustrative example of using the absolute mapping features AIF to determine a relatively precise and absolute position is as follows. As in Fig. As shown in Figure 5, the captured image can indicate that the center of the field of view (FOV) is located at the center of a number of incremental mapping features (IIF). The positional information from the two included absolute mapping features (AIF) indicates which subsection of the XY scale 170B the image contains, for which the included incremental mapping features (IIF) of the XY scale 170B can also be identified. The captured image can then be analyzed by the metrology position coordinate processing section 190 to precisely determine where the center of the field of view (i.e., at coordinates X1, Y1, Z0) occurs within this subsection of the XY scale (i.e., the one containing the two absolute mapping features and the incremental mapping features (IIF)). The process can then proceed as described above (e.g., to appropriately determine the X2 and Y2 coordinates of the end tool position (ETP)).

[0052] Fig. 6A and Fig. 6B are flowcharts that illustrate exemplary implementations of routines 600A and 600B for operating a robot system that includes an articulated robot arm and a system for determining additional measurement position coordinates. As shown in Fig. As shown in Figure 6A, a decision block 610 determines whether the robot system should operate in a mode with additional measurement position coordinates. In various implementations, a user can select and / or activate an operating mode with additional measurement position coordinates or a standard operating mode with robot position coordinates, and / or the system can do so automatically in response to specific operations and / or instructions. For example, in one implementation, the system can enter an operating mode with additional measurement position coordinates (e.g., automatically or in accordance with a user selection) when the articulated robot moves to a specific position (e.g.,a final tool from a general area where assembly or other operations are performed to a more specific area where workpiece inspection operations are typically carried out and where the operating mode with additional metrology position coordinates would be used). In various implementations, such operating modes can be implemented by an external control system ECS (such as the external control system ECS of ). Fig. 1, which uses a standard operating mode section 147 with robot position coordinates and an operating mode section 192 with additional metrology position coordinates). In various implementations, a hybrid operating mode can be operated either independently or as part of an operating mode with additional metrology position coordinates and / or can be implemented as a switch between the operating modes, as described below with reference to Fig. 7 is described in more detail.

[0053] If decision block 610 determines that the robot system should not be operated in an operating mode with additional measurement position coordinates, the routine proceeds to block 620, where the robot system is operated in a standard operating mode with robot position coordinates. As part of the standard operating mode with robot position coordinates, the position sensors (e.g., rotary encoders) of the articulated robot are used to control and determine the movements of the articulated robot and the corresponding end tool position with the robot's accuracy (which is, for example, at least partially based on the accuracy of the articulated robot's position sensors). As mentioned above, the first and second rotary encoders can indicate the positions of the first and second arm sections with a lower degree of accuracy than the position information determined using the XY scale.In general, the operating mode with robot position coordinates can correspond to an independent and / or standard operating mode for the articulated robot (e.g., an operating mode in which the articulated robot is operated independently, such as when a determination system for additional metrology position coordinates is not active or otherwise provided).

[0054] If the robot system is to be operated in a mode with additional measurement position coordinates, the routine proceeds to block 630, where at least one input signal is received (i.e., in an image trigger section) belonging to an end tool position of the articulated robot. A time for a first image acquisition trigger signal is determined based on at least one input signal, and the first image acquisition trigger signal is output to a first image acquisition configuration. The first image acquisition configuration captures a digital image of an XY scale at an image acquisition time in response to receiving the first image acquisition trigger signal. In block 640, the captured image is received (e.g.,in a measurement technology position coordinate processing section), and at least one corresponding mapping-capable feature XY scale that is contained in the captured image, and the associated corresponding known XY scale coordinate location are identified.

[0055] In block 650, a relative position between a movable element from the XY scale or the first image acquisition configuration and the first reference position is determined with an accuracy better than robot accuracy, based on determining the image position of the identified at least one imageable feature in the acquired image. The determined relative position specifies the metrology position coordinates of the end tool position at image acquisition time with an accuracy better than robot accuracy, at least for x and y metrology position coordinates in an xy plane perpendicular to the z-axis. In block 660, the determined position information (e.g., the determined relative position, the determined metrology position coordinates of the end tool position, and / or other associated determined position information) is used for a specified function (e.g.,(for workpiece measurement, positioning control of the articulated robot, etc.). As part of such operations or otherwise, the routine can then proceed to a point A, where in various implementations the routine may end, or may proceed otherwise, as below with reference to . Fig. 6B is described in more detail.

[0056] As in Fig. If block 6B is specified, routine 600B can proceed from point A to block 670. As described in more detail below, as part of routine 600B, the determined position information (e.g., from block 660) can be used to determine a first surface location on a workpiece or in some other way, and a second surface location on the workpiece can then be determined (e.g., as part of a workpiece measurement). In block 670, at least one second input signal is received (e.g., in the image trigger section) that corresponds to the end tool position, and the time of a second image acquisition trigger signal is determined based on this second input signal.The second image acquisition trigger signal is output to the first image acquisition configuration, the first image acquisition configuration capturing a second digital image of the XY scale at a second image acquisition time in response to receiving the second image acquisition trigger signal.

[0057] In block 680, the captured image is received (e.g., in the metrology position coordinate processing section), and at least one second corresponding mapping feature of the XY scale contained in the second captured image, and a corresponding second known XY scale coordinate location, are identified. In block 690, a second relative position between the movable XY scale element or the first image acquisition configuration and the first reference position is determined with an accuracy better than the robot's accuracy, based on determining a second image position of the identified at least one second corresponding mapping feature in the second captured image.The determined second relative position specifies the metrology position coordinates of the end tool position at the second image acquisition time with an accuracy better than the robot accuracy, at least for x and y metrology position coordinates in an xy-plane perpendicular to the z-axis. The second relative position differs from the first relative position and corresponds to a second surface location on the workpiece, which is different from the first surface location.

[0058] In block 695, the first and second relative positions and / or associated position information are used to determine a dimension of the tool corresponding to a distance between the first and second surface locations on the tool, which correspond to the respective end tool positions (such as the contact point positions, etc.) at the first and second image acquisition times. It is understood that instead of using the position sensors (e.g., rotary encoders) of the articulated robot to determine the first and second surface locations on the workpiece with robot accuracy, more precise position information can be determined using techniques such as those described above. In particular, determining the first and second surface locations (i.e.,as they correspond to the first and second locations on the XY scale, for which a precise distance between such locations can be determined using the techniques described above in accordance with the accuracy of the XY scale), so that the corresponding dimension on the workpiece between the first and second surface locations is determined with a high degree of accuracy.

[0059] Fig. Figure 7 is a flowchart illustrating an exemplary implementation of Routine 700 for determining an end tool position, where different techniques can be used during different phases of a movement time. Generally, during the movement time, one or more arm sections of the articulated robot are moved from first rotation positions to second rotation positions (which may include, for example, rotating the arm sections around rotary joints from first rotation orientations to a second rotation orientation). As shown in Fig.As shown in Figure 7, a decision block 710 determines whether a hybrid operating mode is used to determine the end tool position during the movement time. In various implementations, a hybrid operating mode can also represent a process that includes switching between the operating mode with additional measurement position coordinates and the standard operating mode with robot position coordinates. If the hybrid operating mode is not to be used, the routine proceeds to a block 720, where the position sensors (e.g., rotary encoders) of the articulated robot are used alone to determine the end tool position during the movement time.

[0060] If hybrid mode is to be used, the routine proceeds to block 730, during which the position sensors integrated into the articulated robot are used to determine the end tool position during the first segment of the movement time. During such operations, a relative position of a determination system for additional metrology position coordinates cannot be determined and / or is not otherwise used to determine the end tool position. In block 740, during a second segment of the movement time, which occurs after the first segment, a specific relative position of the determination system for additional metrology position coordinates is used to determine the end tool position.It is to be understood that such operations allow the system to perform initial / fast / coarse movement of the end tool position during the first part of the movement time and more accurate final / slower / fine movement of the end tool position during the second part of the movement time.

[0061] It is to be understood that, although the element name “XY scale” has been used in this disclosure in reference to elements 170, 170A, 170B, and the like, this element name is only exemplary and not limiting. It refers to an “XY scale” in relation to a Cartesian coordinate system and its description as comprising a nominally planar substrate nominally oriented perpendicular to the z-axis. More generally, however, the element name XY scale should be understood to refer to any reference scale comprising multiple features or markers corresponding to known two-dimensional coordinates on that reference scale (e.g., exact and / or precisely calibrated locations in two dimensions), provided that the scale can function as disclosed herein.For example, such scale features may be expressed or marked to be in a Cartesian coordinate system on this reference scale, or in a polar coordinate system, or any other suitable coordinate system. Furthermore, such features may include features that are uniformly or non-uniformly distributed over an operational scale range, and may include subdivided or undivided scale markings, provided that such features correspond to known two-dimensional coordinates on the scale and can function as disclosed herein.

[0062] It should be understood that, although the robot system disclosed and presented here is shown in general terms and described with reference to two arm sections (e.g., the first arm section 120 and the second arm section 130), it is not so limited. In various implementations, the robot system, provided that it contains two arm sections such as those described and / or claimed here, can include additional arm sections if desired.

[0063] It is understood that the XY scale or reference scale and a camera used to record the scale may rotate relative to each other, depending on the movement and / or position of the robot system. It is understood that prior art methods (such as those disclosed in the incorporated references) can be used to accurately determine any such relative rotation and / or to perform any necessary coordinate transformations and / or to analyze the relative position of the camera and the scale according to the principles disclosed herein, despite such relative rotations. It is understood that the metrology position coordinates referenced herein can account for any such rotations.Furthermore, it should be understood that in some implementations the metrology position coordinates referred to here may include a set of coordinates that contain a precise determination and / or specification of any such relative rotation, if desired.

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