CN114012784A - Calibration device and calibration method for robot tool coordinate system - Google Patents
Calibration device and calibration method for robot tool coordinate system Download PDFInfo
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- CN114012784A CN114012784A CN202111209743.6A CN202111209743A CN114012784A CN 114012784 A CN114012784 A CN 114012784A CN 202111209743 A CN202111209743 A CN 202111209743A CN 114012784 A CN114012784 A CN 114012784A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
- B25J19/0095—Means or methods for testing manipulators
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1679—Programme controls characterised by the tasks executed
- B25J9/1692—Calibration of manipulator
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
- Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
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Abstract
The invention discloses a calibration device and a calibration method of a robot tool coordinate system, wherein the calibration device of the robot tool coordinate system comprises a tool calibration workbench, the tool calibration workbench comprises a working platform, a first light beam sensor and a second light beam sensor, the first light beam sensor and the second light beam sensor are respectively provided with a first light beam and a second light beam, the first light beam and the second light beam are both parallel to the upper surface of the working platform, and the first light beam and the second light beam are arranged in a cross way in different surfaces. When the calibration device of the robot tool coordinate system in the embodiment is used for calibrating the tool, under the condition that the tail end of the tool is not as thick, the calculated deviation of the tool in the Z-axis direction can be reduced or avoided, and the precision of tool calibration is further improved. In addition, the first light beam and the second light beam do not need to intersect, and the processing and assembling difficulty of the calibration device is reduced.
Description
Technical Field
The invention relates to a calibration device and a calibration method of a robot tool coordinate system.
Background
The final purpose of tool calibration of the industrial robot is to obtain a transformation matrix of a tool coordinate system relative to a robot end flange coordinate system, so that the accuracy of actual track running is guaranteed. The existing robot tool calibration mainly adopts a robot teaching mode or adopts external position measuring equipment to calibrate. The robot teaching mode is that the robot is controlled to touch the origin of the coordinate system of the tool with a fixed point in space under different postures, so that the value of the origin of the coordinate system of the tool is calculated. The method is simple and easy to operate, but is difficult to operate practically, inaccurate in calibration result, with human errors, and only suitable for tools with obvious characteristic points. Another method for calibration using external position measuring devices, such as industrial cameras, laser trackers, three-coordinate measuring machines, etc., has high precision, but is relatively expensive and complex to operate, and requires professional technicians. The method adopting robot teaching in the prior art has the following technical problems:
1) a section of the tail end of the applicable tool needs to be equal in thickness, otherwise, the determined tool coordinate system has deviation in the Z-axis direction, and the calibration accuracy of the tool is further influenced;
2) an operator determines that the tail end of the tool is positioned at the intersection center of the laser beams through human vision, and the precision cannot be guaranteed;
3) it takes a long time for the operator to control the coincidence of the tool tip with the center of the intersection of the laser beams.
Disclosure of Invention
The invention aims to solve the technical problem that a section of the tail end of a tool applicable to tool calibration in a robot teaching mode in the prior art needs to be as thick as possible, otherwise, the determined tool coordinate system has deviation in the Z-axis direction, and provides a calibration device and a calibration method of a robot tool coordinate system.
The invention solves the technical problems through the following technical scheme:
the invention provides a calibration device of a robot tool coordinate system, which comprises a tool calibration workbench, wherein the tool calibration workbench comprises a workbench, a first light beam sensor and a second light beam sensor, the first light beam sensor and the second light beam sensor are respectively provided with a first light beam and a second light beam, the first light beam and the second light beam are both parallel to the upper surface of the workbench, and the first light beam and the second light beam are arranged in a cross way in different surfaces.
In this embodiment, with the above structure, when the calibration device of the robot tool coordinate system in this embodiment is used to calibrate a tool, under the condition that the ends of the tool are not as thick, the calculated Z-axis direction deviation of the tool can be reduced or avoided, and the precision of tool calibration is further improved. In addition, the first light beam and the second light beam do not need to intersect, and the processing and assembling difficulty of the calibration device is reduced.
Preferably, orthographic projections of the first light beam and the second light beam on the working platform are perpendicular to each other.
Preferably, the first beam sensor is a laser sensor, and the first beam is a laser beam;
the second beam sensor is a laser sensor, and the second beam is a laser beam.
In the scheme, by adopting the structure, the laser sensor can quickly identify whether the blocking or non-blocking is caused by good linearity and small divergence of the laser, so that the measurement deviation can be reduced or avoided.
The invention also provides a calibration method of the robot tool coordinate system, which is used for calibrating the tool coordinate system of the robot by adopting the calibration device of the robot tool coordinate system, and comprises the following steps:
s1, setting a first track line which is parallel to the upper surface of the working platform, controlling a tool to move along the first track line, wherein the tool is provided with a tail end, and the first track line enables the tail end to block the first light beam;
s2, recording the position of a flange connected with the tool as a first position at the moment when the tail end blocks the first light beam; recording the position of the flange as a second position at the moment when the tail end leaves the first light beam;
s3, setting a second trajectory line, the second trajectory line being located below the first trajectory line, and the orthographic projection of the first trajectory line on the working platform being coincident with the orthographic projection of the second trajectory line on the working platform, controlling the tool to move along the second trajectory line, the second trajectory line enabling the tip to block the first light beam;
s4, recording the position of the flange as a third position at the moment when the tail end blocks the first light beam; recording the position of the flange as a fourth position at the moment when the tail end leaves the first light beam;
s5, taking the middle point of the first position and the second position as a fifth position, taking the middle point of the third position and the fourth position as a sixth position, wherein the straight line direction passing through the fifth position and the sixth position is the Z-axis direction of the tool coordinate system;
and S6, calculating the tool coordinate system and completing the calibration of the tool coordinate system.
In the scheme, the tail end blocks the first light beam twice, and when the tool blocks along the first track line, a first position and a second position are obtained; when the tool is blocked along the second trajectory line, the third position and the fourth position are obtained, and the thickness deviation of the two blocking sections can be calculated, so that the calibration method can be suitable for the condition that the tail ends are not as thick. In general, the calibration method adopted in this embodiment can reduce or avoid the calculated Z-axis direction deviation under the condition of unequal thicknesses of the ends, and further improve the precision of tool calibration.
Preferably, step S6 includes the following steps:
s61, setting the intersection of the orthographic projection of the second light beam and the orthographic projection of the first light beam as a first point, and marking the point corresponding to the first point on the second light beam as an intersection point;
s62, controlling the tail end to move to the intersection point, recording the position of the flange, and recording the position as a seventh position;
s63, the control tool keeps different postures and repeats S62 for three times, and the positions of the flange are recorded as an eighth position, a ninth position and a tenth position respectively;
and S64, completing the calibration of the tool coordinate system according to the Z-axis direction, the seventh position, the eighth position, the ninth position and the tenth position.
In the scheme, the tool coordinate system is calibrated by using a four-point method according to the Z-axis direction, so that the precision of tool calibration is further improved.
Preferably, step S62 includes the following steps:
s621, the second light beam is located below the first light beam, the tail end is controlled to move to one end of the second light beam, and the position of the flange is recorded and recorded as an eleventh position;
s622, controlling the tail end to be located at the other end of the second light beam, and recording the position of the flange as a twelfth position;
s623, setting a third trajectory line, where the third trajectory line is located above the second light beam, an orthographic projection of the third trajectory line on the working platform coincides with an orthographic projection of the second light beam on the working platform, a point on the third trajectory line corresponding to the eleventh position is denoted as a thirteenth position, a point on the third trajectory line corresponding to the twelfth position is denoted as a fourteenth position, when the terminal is controlled to move between the thirteenth position and the fourteenth position, the terminal can be located on the first light beam, and when the terminal is located on the first light beam, a position of the flange is recorded, and is denoted as a fifteenth position, which is the seventh position.
In the scheme, the positioning point is found when the positioning point moves between the thirteenth position and the fourteenth position, so that the positioning precision is effectively improved. In addition, the first light beam and the second light beam do not need to intersect, and the processing and assembling difficulty of a device consisting of the first light beam and the second light beam is reduced.
Preferably, step S621 includes the following steps:
s6211, when the second light beam is located below the first light beam and the tail end is located at one end of the second light beam through bisection, recording the position of the flange, and marking the position as a sixteenth position, namely the eleventh position;
step S622 includes the steps of:
s6221, recording the position of the flange when the tail end is positioned at the other end of the second light beam through bisection, and marking the position as a seventeenth position, namely the twelfth position;
step S623 includes the steps of:
s6231, recording the position of the flange when the tail end is positioned on the first light beam through bisection, and marking the position as an eighteenth position, namely the seventh position.
In the scheme, a dichotomy method is adopted, and after a plurality of experiments, an effective and gradual approximation method is adopted to find the pose when the tail end is positioned at one end of the second light beam, the pose when the tail end is positioned at the other end of the second light beam and the pose when the tail end is positioned on the first light beam, so that an operator does not need to manually find a positioning point through naked eyes, and the positioning precision is improved; and the tail end can quickly and accurately reach the positioning point to record the sixteenth position, the seventeenth position and the eighteenth position to obtain the seventh position.
Preferably, a tool calibration workbench is adopted to calibrate the tool of the robot, the robot comprises a control system and the flange, one end of the control system is connected with the flange to control the movement of the tool, and the other end of the control system is connected with the first light beam sensor and the second light beam sensor.
In the scheme, the structural form is adopted, the control system is used for receiving the signals transmitted by the light beam sensor and recording the real-time pose of the flange, the automation degree is high, and the tool calibration precision is further improved.
Preferably, each of said first and second beam sensors comprises a beam transmitter and a beam receiver, respectively, said beam receiver sending a blocking signal to said control system at the instant when said tip blocks said first or second beam, said control system being capable of recording the current position of said flange; at the instant when the tip leaves the first beam or the second beam, the beam receiver sends a received signal to the control system, which is able to record the current position of the flange.
In the scheme, by adopting the structural form, whether the tail end blocks the first light beam or the second light beam is not required to be judged by an operator through naked eyes, the real-time pose of the flange is recorded through the matching relation among the first light beam sensor, the second light beam sensor and the control system, the automation degree is high, the measurement error is reduced or avoided, and the positioning precision is improved.
Preferably, step S6211 includes the steps of:
s62111, setting a fourth track line which is parallel to the upper surface of the working platform and is positioned at one end of the second light beam, and controlling the tool to move along the fourth track line, wherein the fourth track line enables the tail end to block the second light beam;
s62112, recording the position of the flange at the moment when the tail end blocks the second light beam, and recording the position as a nineteenth position;
s62113, setting a fifth trajectory line, wherein the trajectory line is located above the fourth trajectory line, and the fifth trajectory line is coincident with the orthographic projection of the fourth trajectory line on the working platform, and controlling the tip to be incapable of blocking the second light beam when the tool keeps the current posture and moves along the fifth trajectory line;
s62114, setting a sixth trajectory line so that the sixth trajectory line is located at the right middle of the fourth trajectory line and the fifth trajectory line in the vertical direction, controlling the tool to keep the current posture to move along the sixth trajectory line, and judging whether the tail end blocks the second light beam;
s62115, if the tail end can block the second light beam, continuously moving the translation track of the tool upwards from the sixth track line by bisection until the moment that the control system receives the blocking signal and switches to the receiving signal, and recording the position of the flange as a twentieth position, namely the eleventh position;
and if the tail end can not block the second light beam, continuously moving the translation track of the tool upwards from the fourth track line by bisection until the moment that the control system receives a blocking signal and switches to a receiving signal, recording the position of the flange, and marking the position as a twenty-first position, namely the eleventh position.
In the scheme, the dichotomy is adopted, and a series of effective and gradual approaching steps are adopted to find the pose when the tail end is positioned at one end of the second light beam through a plurality of experiments, so that an operator does not need to manually find a positioning point through naked eyes, and the positioning precision is improved.
The positive progress effects of the invention are as follows:
when the calibration device of the robot tool coordinate system in the embodiment is used for calibrating the tool, under the condition that the tail end of the tool is not as thick, the calculated deviation of the tool in the Z-axis direction can be reduced or avoided, and the precision of tool calibration is further improved. In addition, the first light beam and the second light beam do not need to intersect, and the processing and assembling difficulty of the calibration device is reduced.
Drawings
Fig. 1 is a schematic structural diagram of a calibration apparatus for a robot tool coordinate system according to a preferred embodiment of the present invention.
Fig. 2 is a flowchart illustrating a method for calibrating a coordinate system of a robot tool according to a preferred embodiment of the invention.
Fig. 3 is a schematic structural diagram of another angle of the calibration apparatus for the coordinate system of the robot tool according to the preferred embodiment of the invention.
Fig. 4 is a schematic structural diagram of another angle of the calibration apparatus for the coordinate system of the robot tool according to the preferred embodiment of the invention.
Fig. 5 is a schematic diagram illustrating the calibration of the Z-axis direction in the calibration method of the robot tool coordinate system according to the preferred embodiment of the invention.
Fig. 6 is a schematic diagram illustrating the seventh position, the eighth position, the ninth position and the tenth position in step S6 of the method for calibrating a coordinate system of a robot tool according to the preferred embodiment of the present invention.
Description of reference numerals:
First light beam sensor 11
First light beam 111
Second light beam sensor 12
Working platform 13
First trajectory line L1
Second trajectory line L2
Z-axis direction LZ
First position P1
Second position P2
Third position P3
Fourth position P4
Fifth position P5
Sixth position P6
Seventh position P7
Eighth position P8
Ninth position P9
Tenth position P10
Detailed Description
The present invention is further illustrated by the following examples, but is not limited thereby in the scope of the following examples.
As shown in fig. 1, an embodiment of the present invention provides a calibration apparatus for a coordinate system of a robot tool, including a tool calibration table 1, where the tool calibration table 1 includes a working platform 13, a first light beam sensor 11 and a second light beam sensor 12, the first light beam sensor 11 and the second light beam sensor 12 respectively have a first light beam 111 and a second light beam 121, the first light beam 111 and the second light beam 121 are both parallel to an upper surface of the working platform 13, and the first light beam 111 and the second light beam 121 are arranged in a manner of intersecting with each other. The term "non-coplanar cross arrangement" herein means that the orthographic projections of the first and second light beams 111 and 121 on the working platform 13 cross each other, and the first and second light beams 111 and 121 have a distance in the direction perpendicular to the extending direction of the working platform 13. When the calibration device of the robot tool coordinate system in the embodiment is used for calibrating the tool, under the condition that the tail end of the tool is not as thick, the calculated deviation of the tool in the Z-axis direction can be reduced or avoided, and the precision of tool calibration is further improved. In addition, the first light beam 111 and the second light beam 121 do not need to intersect, and the processing and assembling difficulty of the calibration device is reduced.
Preferably, the distance between the first beam 111 and the second beam 121 in the direction perpendicular to the extension of the work platform 13 is 5mm to 15 mm. The distance between the first light beam 111 and the second light beam 121 is too long, so that the occupied space of the whole device is increased; the distance is too short, and the tool 2 is likely to touch other light beams by mistake when moving.
In a preferred embodiment, the orthographic projections of the first light beam 111 and the second light beam 121 on the working platform 13 are perpendicular to each other.
Of course, in other embodiments, the orthographic projection of the first light beam 111 on the work platform 13 and the orthographic projection of the second light beam 121 on the work platform 13 may not be perpendicular to each other.
In a preferred embodiment, the first beam sensor 11 is a laser sensor, and the first beam 111 is a laser beam; the second beam sensor 12 is a laser sensor and the second beam 121 is a laser beam. Because the laser linearity is good and the divergence is small, the laser sensor can quickly identify whether the blocking or the non-blocking occurs, and the measurement deviation can be reduced or avoided.
As shown in fig. 1, fig. 2 and fig. 5, an embodiment of the present invention further provides a calibration method for a robot tool coordinate system, where the calibration device for a robot tool coordinate system according to any of the embodiments is used to calibrate the tool coordinate system of a robot, and the calibration method for a robot tool coordinate system includes the following steps:
s1, setting a first trajectory line L1, the first trajectory line L1 being parallel to the upper surface of the work platform 13, controlling a tool 2 to move along the first trajectory line L1, the tool 2 having a tip 21, the first trajectory line L1 enabling the tip 21 to block the first light beam 111, wherein the tip 21 refers to a linear portion of the tip in the tool 2;
s2, recording the position of the flange 3 connected to the tool 2 as the first position P1 at the moment when the tip 21 blocks the first light beam 111; recording the position of the flange 3 at the instant when the end 21 leaves the first light beam 111, as a second position P2, wherein the position of the flange 3 is the position of the center point of the flange 3 in six-dimensional space, and wherein a cross section of the first light beam 111 is shown in fig. 5;
s3, setting a second trajectory line L2, the second trajectory line L2 being located below the first trajectory line L1, and the orthographic projection of the first trajectory line L1 on the work platform 13 coinciding with the orthographic projection of the second trajectory line L2 on the work platform 13, the control tool 2 moving along the second trajectory line L2, the second trajectory line L2 enabling the tip 21 to block the first light beam 111;
s4, recording the position of the flange 3 as a third position P3 at the moment when the tail end 21 blocks the first light beam 111; the moment when the end 21 leaves the first light beam 111, the position of the flange 3 is recorded, denoted as fourth position P4;
s5, taking the midpoint of the first position P1 and the second position P2 as a fifth position P5, taking the midpoint of the third position P3 and the fourth position P4 as a sixth position P6, wherein the linear directions of the fifth position P5 and the sixth position P6 are the Z-axis direction L of the tool coordinate systemZ；
And S6, calculating a tool coordinate system and finishing the calibration of the tool coordinate system.
In the present embodiment, when the tool 2 blocks the first light beam 111 along the first trajectory line L1, one side of the end 21 is tangent to the first light beam 111 at a point Q1, which results in a first position P1, and when the tool 2 leaves the first light beam 111 along the first trajectory line L1, the other side of the end 21 is tangent to the first light beam 111 at a point Q2, which results in a second position P2; similarly, when the tool 2 blocks the first light beam 111 along the second trajectory line L2, one side of the end 21 is tangent to the first light beam 111, the tangent point is Q3, the third position P3 is obtained, when the tool 2 leaves the first light beam 111 along the second trajectory line L2, the other side of the end 21 is tangent to the first light beam 111, the tangent point is Q4, the fourth position P4 is obtained, since the flange 3 and the end 21 are relatively stationary, the Q1, Q2, Q3, Q4 and P1, P2, P3, P4 are obtained, and the relationship between the two sets of position points can correspond, since the midpoint Q5 of Q1 and Q2 is relative to the extending direction of the end 21, the connecting line of the midpoint Q6 of Q3 and Q4 is the extending direction of the end 21, the fifth position P2 of the midpoints of the first position P1 and the second position P2 is the extending direction of the sixth position P2, i.e. the connecting line of the extending direction of the end 2 of the third position P2 and the sixth position P2 is the extending direction of the end 3621, i.Z. The tip 21 twice interrupts the first light beam 111, and the tool 2, when interrupted along the first trajectory line L1, results in a first position P1 and a second position P2; the tool 2, when interrupted along the second trajectory line L2, results in a third position P3 and a fourth positionSince the difference in thickness between the two blocking sections can be calculated by setting P4, the calibration method can be applied to the case where the end 21 is not as thick. In general, the calibration method employed in the present embodiment can reduce or avoid the calculated Z-axis direction L under the condition that the ends 21 are not as thickZAnd deviation occurs, so that the calibration precision of the tool is further improved.
In practice, the extension direction of the end 21 is controlled to be perpendicular to the upper surface of the working platform 13.
As shown in fig. 6, as a preferred embodiment, step S6 includes the following steps:
s61, setting a first point at an intersection of the orthographic projection of the second light beam 121 and the orthographic projection of the first light beam 111, and marking a point on the second light beam 121 corresponding to the first point as an intersection, wherein a connecting line between the first point and the intersection is perpendicular to the upper surface of the working platform 13;
s62, controlling the tail end 21 to move to the intersection point, recording the position of the flange 3, and recording as a seventh position P7;
s63, repeating S62 three times while keeping different postures of the control tool 2, and recording the positions of the flange 3 as an eighth position P8, a ninth position P9 and a tenth position P10;
s64, according to the Z-axis direction LZThe seventh position P7, the eighth position P8, the ninth position P9 and the tenth position P10 complete the calibration of the tool coordinate system.
In the present embodiment, the Z-axis direction L is usedZAnd a four-point method is used for calibrating a tool coordinate system, so that the precision of tool calibration is further improved.
As shown in fig. 4, as a preferred embodiment, step S62 includes the following steps:
s621, the second light beam 121 is located below the first light beam 111, and the control end 21 moves to one end of the second light beam 121, and records the position of the flange 3 as an eleventh position;
s622, controlling the end 21 to be located at the other end of the second light beam 121, and recording the position of the flange 3 as a twelfth position;
s623, setting a third trajectory line, where the third trajectory line is located above the second light beam 121, an orthogonal projection of the third trajectory line on the working platform 13 coincides with an orthogonal projection of the second light beam 121 on the working platform 13, a point on the third trajectory line corresponding to the eleventh position is denoted as a thirteenth position, and a point on the third trajectory line corresponding to the twelfth position is denoted as a fourteenth position, where a connection line direction between the eleventh position and the thirteenth position is perpendicular to the upper surface of the working platform 13, and a connection line direction between the twelfth position and the fourteenth position is perpendicular to the upper surface of the working platform 13. The position of the recording flange 3 when the tip 21 is controlled to move between the thirteenth position and the fourteenth position, the tip 21 being able to be located on the first light beam 111, when the tip 21 is located on the first light beam 111, i.e. the bottom end point of the tip 21 is on the first light beam 111, is denoted as the fifteenth position, i.e. the seventh position P7.
In the embodiment, the first light beam 111 and the second light beam 121 do not need to intersect, which reduces the difficulty in processing and assembling the device composed of the first light beam 111 and the second light beam 121. In addition, the seventh position P7 of the positioning point is found when the positioning point moves between the thirteenth position and the fourteenth position, so that the positioning accuracy is effectively improved. Similarly, the eighth position P8, the ninth position P9, and the tenth position P10 can also be obtained by the method in the present embodiment.
As a preferred embodiment, step S621 includes the following steps:
s6211, when the second light beam 121 is located below the first light beam 111, and the terminal 21 is located at one end of the second light beam 121 by bisection, recording the position of the flange 3, which is marked as a sixteenth position, that is, an eleventh position;
step S622 includes the steps of:
s6221, recording the position of the flange 3 when the tail end 21 is positioned at the other end of the second light beam 121 through bisection, and marking the position as a seventeenth position, namely a twelfth position;
step S623 includes the steps of:
s6231, recording the position of the flange 3 when the tip 21 is positioned on the first light beam 111 by bisection, which is referred to as an eighteenth position, i.e., a seventh position.
In the embodiment, a dichotomy is adopted, and after a plurality of experiments, an effective and gradual approximation method is adopted to find the pose when the tail end 21 is located at one end of the second light beam 121, the pose when the tail end 21 is located at the other end of the second light beam 121, and the pose when the tail end 21 is located on the first light beam 111, so that an operator does not need to manually find a positioning point through naked eyes, and the positioning accuracy is improved; and, the end 21 can be made to reach the positioning point quickly and accurately to record the sixteenth position, the seventeenth position, and the eighteenth position to obtain the seventh position.
As shown in fig. 2, 3 and 4, as a preferred embodiment, the robot comprises a control system and a flange 3, the control system being connected at one end to the flange 3 for controlling the movement of the tool 2 and at the other end to a first beam sensor 11 and a second beam sensor 12. The first light beam sensor 11 and the second light beam sensor 12 are respectively connected to a control system through an I/O interface, and the control system can receive signals transmitted by the first light beam sensor 11 and the second light beam sensor 12 in real time; the control system comprises an upper computer which can read the real-time state and pose data of the robot (namely the flange 3) and process the data. The control system receives signals transmitted by the first light beam sensor 11 and the second light beam sensor 12, and can record the real-time pose of the flange 3, so that the automation degree is high, and the tool calibration precision is further improved.
As a preferred embodiment, the first and second light beam sensors 11 and 12 each comprise a light beam emitter and a light beam receiver, respectively, which send a blocking signal to the control system, which is able to record the current position of the flange 3, at the instant when the end 21 blocks the first or second light beam 111 or 121; at the instant when the end 21 leaves the first beam 111 or the second beam 121, the beam receiver sends a reception signal to the control system, which is able to record the current position of the flange 3. An operator does not need to judge whether the tail end 21 blocks the first light beam 111 or the second light beam 121 by naked eyes, and the real-time pose of the flange 3 is recorded through the matching relationship among the first light beam sensor 11, the second light beam sensor 12 and the control system, so that the automation degree is high, the measurement error is reduced or avoided, and the positioning precision is improved.
As a preferred embodiment, step S6211 includes the following steps:
s62111, setting a fourth trace parallel to the upper surface of the working platform 13 and located at one end of the second light beam 121, wherein the fourth trace enables the terminal 21 to block the second light beam 121 when the control tool 2 moves along the fourth trace;
s62112, recording the position of the flange 3 at the moment when the tail end 21 blocks the second light beam 121, and recording the position as a nineteenth position;
s62113, setting a fifth trajectory line, wherein the trajectory line is located above the fourth trajectory line, and the orthographic projection of the fifth trajectory line and the orthographic projection of the fourth trajectory line on the working platform 13 coincide, and when the control tool 2 keeps the current posture to move along the fifth trajectory line, the tail end 21 cannot block the second light beam 121;
s62114, setting the sixth trajectory line so that the sixth trajectory line is located at the middle of the fourth trajectory line and the fifth trajectory line in the vertical direction, controlling the tool 2 to keep the current posture to move along the sixth trajectory line, and determining whether the tip 21 blocks the second light beam 121;
s62115, if the tip 21 can block the second light beam 121, estimating the distance X between the tip at the bottom of the tip 21 and the second light beam 121 by bisecting the translation trajectory of the tool 2 moving up from the sixth trajectory1Setting a trajectory line a1So that the trajectory line a1Is located right above the sixth track line and has a distance X1/2, control tool 2 along trajectory a1Moving; setting a trajectory line a2So that the trajectory line a2Located on the track line a1Is right above and at a distance X1/4, control tool 2 along trajectory a2Moving; setting a trajectory line a3So that the trajectory line a3Located on the track line a2Is right above and at a distance X1/8, control tool 2 along trajectory a3Moving; … …, respectively; until the moment when the control system receives the blocking signal and switches to receive the receiving signal, if the control system is set to receive the electric signal '1' when the tail end 21 blocks the second laser beam 121, and to control the second laser beam 121 when the tail end 21 does not block the second laser beam 121The system receives an electric signal '0', and when the electric signal received by the control system is converted from '1' to '0', namely the tail end 21 just does not block the second light beam 121, the position of the flange 3 is recorded as the twentieth position, namely the eleventh position;
if the end 21 cannot block the second light beam 121, the distance X between the end of the bottom 21 and the second light beam 121 is estimated by dividing the translation trajectory of the tool 2 from the fourth trajectory continuously2Setting a trajectory line b1So that the trajectory line b1Is located right above the fourth track line and has a distance X2/2, control tool 2 along trajectory b1Moving; set trajectory line b2So that the trajectory line b2Located on the track line b1Is right above and at a distance X2/4, control tool 2 along trajectory b2Moving; set trajectory line b3So that the trajectory line b3Located on the track line b2Is right above and at a distance X2/8, control tool 2 along trajectory b3Moving; … …, respectively; and recording the position of the flange 3 as the twenty-first position, namely the eleventh position, until the moment when the control system receives the blocking signal and switches to receive the signal, namely the tail end 21 just does not block the second light beam 121 and the bottom end point of the tail end 21 is just above the second light beam 121.
In the embodiment, a dichotomy is adopted, and a series of effective and gradual approximation steps are adopted to find the pose when the tail end 21 is located at one end of the second light beam 121 through a plurality of experiments, so that an operator does not need to manually find a positioning point through naked eyes, and the positioning accuracy is improved.
Similarly, the specific steps of the dichotomy in this embodiment may also be adopted when determining the seventeenth position and the eighteenth position.
In a specific operation, the extending direction of the adjusting tip 21 is as perpendicular as possible to the upper surface of the working platform 13, and this posture is maintained. Controlling the tool 2 to keep the current attitude moving along the first trajectory line L1, and recording the position of the flange 3 connected to the tool 2 at the instant when the tip 21 interrupts the first light beam 111, as the first position P1; when the end 21 leaves the first beam 111The position of the flange 3 is recorded as the second position P2. The control means 2 keep the current attitude moving along the second trajectory line L2, recording the position of the flange 3 at the instant when the tip 21 interrupts the first light beam 111, as the third position P3; the position of the flange 3 is recorded at the instant when the end 21 leaves the first light beam 111, denoted as fourth position P4. Taking the midpoint between the first position P1 and the second position P2 as the fifth position P5, taking the midpoint between the third position P3 and the fourth position P4 as the sixth position P6, and the linear directions of the fifth position P5 and the sixth position P6 are the Z-axis direction L of the tool coordinate systemZ。
The adjustment tip 21 extends in a direction as perpendicular as possible to the upper surface of the work platform 13, and this posture is maintained. The control means 2 is moved to near one end of the second beam 121 and the control means 2 is moved along a fourth trajectory, the tip 21 being capable of interrupting the second beam 121. The control means 2 moves along the fifth trajectory and the tip 21 cannot block the second light beam 121. The control means 2 keeps the current posture moving along the sixth trajectory line (the sixth trajectory line is located at the right middle of the fourth trajectory line and the fifth trajectory line in the vertical direction), and determines whether the end portion interrupts the second light beam 121. If the tail end 21 can block the second light beam 121, continuously moving the translation track of the tool 2 up from the sixth track line by bisection until the moment that the control system receives the blocking signal and switches to receive the receiving signal, namely when the tail end 21 just does not block the second light beam 121, recording the position of the flange 3, and marking the position as a twenty-first position, namely an eleventh position; if the end 21 cannot block the second light beam 121, the translation track of the tool 2 is continuously moved up by bisection from the fourth track line until the moment when the control system receives the blocking signal and switches to receive the receiving signal, that is, when the end 21 just does not block the second light beam 121, the position of the flange 3 is recorded as a twenty-second position, that is, an eleventh position. The control means 2 moves to the vicinity of the other end of the second beam 121 and repeats the preceding steps to obtain the twelfth position.
The control means 2 moves from the eleventh position to the twelfth position and the tip 21 is able to interrupt the first laser beam 111, this track being denoted as the ninth track. A tenth trajectory is set, the tenth trajectory being located directly above the ninth trajectory, the tip 21 being unable to interrupt the first light beam 111 when the control tool 2 is moved along the tenth trajectory. The eleventh trajectory line is set so that the eleventh trajectory line is located at the very middle of the ninth trajectory line and the tenth trajectory line in the vertical direction, and the control means 2 moves along the eleventh trajectory line while keeping the current posture, and determines whether or not the tip 21 interrupts the first light beam 111. If the end 21 can block the first light beam 111, continuously moving the translation track of the tool 2 up by bisection from the eleventh track line until the moment when the control system receives the blocking signal and switches to receive the receiving signal, that is, when the end 21 just does not block the first light beam 111, recording the position of the flange 3, which is recorded as the twenty-second position, that is, the seventh position P7; if the end 21 is unable to interrupt the first light beam 111, the translation trajectory of the tool 2 is continuously shifted up by bisection from the ninth trajectory line until the moment the control system receives the interrupt signal and switches to receive the signal, i.e. the end 21 just does not interrupt the first light beam 111, the position of the flange 3 is recorded as the twenty-third position, i.e. the seventh position P7. The control means 2 repeats this segment of the preceding steps three times while keeping the different postures, recording the positions of the flange 3, respectively, as eighth position P8, ninth position P9 and tenth position P10.
According to the Z-axis direction LZThe seventh position P7, the eighth position P8, the ninth position P9 and the tenth position P10 complete the calibration of the tool coordinate system.
The circles designated by P1, P2, P3, P4, P5, P6, P7, P8, P9, and P10 in fig. 5 and 6 are not solid, and only indicate the position of the flange at this time.
While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.
Claims (10)
1. The calibration device of the robot tool coordinate system is characterized by comprising a tool calibration workbench, wherein the tool calibration workbench comprises a working platform, a first light beam sensor and a second light beam sensor, the first light beam sensor and the second light beam sensor are respectively provided with a first light beam and a second light beam, the first light beam and the second light beam are parallel to the upper surface of the working platform, and the first light beam and the second light beam are arranged in a cross mode in different planes.
2. Calibration arrangement for a robot tool coordinate system according to claim 1, characterized in that the orthographic projections of the first light beam and the second light beam on the work platform are perpendicular to each other.
3. Calibration arrangement of a robot tool coordinate system according to claim 1, characterized in that the first beam sensor is a laser sensor and the first beam is a laser beam;
the second beam sensor is a laser sensor, and the second beam is a laser beam.
4. A calibration method of a robot tool coordinate system, characterized in that the tool coordinate system of a robot is calibrated using a calibration apparatus of a robot tool coordinate system according to any of claims 1-3, the calibration method of the robot tool coordinate system comprising the steps of:
s1, setting a first track line which is parallel to the upper surface of the working platform, controlling a tool to move along the first track line, wherein the tool is provided with a tail end, and the first track line enables the tail end to block the first light beam;
s2, recording the position of a flange connected with the tool as a first position at the moment when the tail end blocks the first light beam; recording the position of the flange as a second position at the moment when the tail end leaves the first light beam;
s3, setting a second trajectory line, the second trajectory line being located below the first trajectory line, and the orthographic projection of the first trajectory line on the working platform being coincident with the orthographic projection of the second trajectory line on the working platform, controlling the tool to move along the second trajectory line, the second trajectory line enabling the tip to block the first light beam;
s4, recording the position of the flange as a third position at the moment when the tail end blocks the first light beam; recording the position of the flange as a fourth position at the moment when the tail end leaves the first light beam;
s5, taking the middle point of the first position and the second position as a fifth position, taking the middle point of the third position and the fourth position as a sixth position, wherein the straight line direction passing through the fifth position and the sixth position is the Z-axis direction of the tool coordinate system;
and S6, calculating the tool coordinate system and completing the calibration of the tool coordinate system.
5. Calibration method of a robot tool coordinate system according to claim 4,
step S6 includes the following steps:
s61, setting the intersection of the orthographic projection of the second light beam and the orthographic projection of the first light beam as a first point, and marking the point corresponding to the first point on the second light beam as an intersection point;
s62, controlling the tail end to move to the intersection point, recording the position of the flange, and recording the position as a seventh position;
s63, the control tool keeps different postures and repeats S62 for three times, and the positions of the flange are recorded as an eighth position, a ninth position and a tenth position respectively;
and S64, completing the calibration of the tool coordinate system according to the Z-axis direction, the seventh position, the eighth position, the ninth position and the tenth position.
6. Method for calibration of a robot tool coordinate system according to claim 5,
step 62 comprises the steps of:
s621, the second light beam is located below the first light beam, the tail end is controlled to move to one end of the second light beam, and the position of the flange is recorded and recorded as an eleventh position;
s622, controlling the tail end to be located at the other end of the second light beam, and recording the position of the flange as a twelfth position;
s623, setting a third trajectory line, where the third trajectory line is located above the second light beam, an orthographic projection of the third trajectory line on the working platform coincides with an orthographic projection of the second light beam on the working platform, a point on the third trajectory line corresponding to the eleventh position is denoted as a thirteenth position, a point on the third trajectory line corresponding to the twelfth position is denoted as a fourteenth position, when the terminal is controlled to move between the thirteenth position and the fourteenth position, the terminal can be located on the first light beam, and when the terminal is located on the first light beam, a position of the flange is recorded, and is denoted as a fifteenth position, which is the seventh position.
7. Method for calibration of a robot tool coordinate system according to claim 6,
step S621 includes the steps of:
s6211, when the second light beam is located below the first light beam and the tail end is located at one end of the second light beam through bisection, recording the position of the flange, and marking the position as a sixteenth position, namely the eleventh position;
step S622 includes the steps of:
s6221, recording the position of the flange when the tail end is positioned at the other end of the second light beam through bisection, and marking the position as a seventeenth position, namely the twelfth position;
step S623 includes the steps of:
s6231, recording the position of the flange when the tail end is positioned on the first light beam through bisection, and marking the position as an eighteenth position, namely the seventh position.
8. A method of calibration of a robot tool coordinate system according to claim 7, characterized in that the robot comprises a control system and the flange, the control system being connected at one end to the flange for controlling the movement of the tool and at the other end to the first and second beam sensors.
9. A method of calibration of a robot tool coordinate system according to claim 8, characterized in that the first and the second light beam sensor each comprise a light beam emitter and a light beam receiver, respectively, which light beam receiver sends a blocking signal to the control system when the tip blocks the first or the second light beam, which control system is able to record the current position of the flange; at the instant when the tip leaves the first beam or the second beam, the beam receiver sends a received signal to the control system, which is able to record the current position of the flange.
10. Method for calibration of a robot tool coordinate system according to claim 9,
step S6211 includes the steps of:
s62111, setting a fourth track line which is parallel to the upper surface of the working platform and is positioned at one end of the second light beam, and controlling the tool to move along the fourth track line, wherein the fourth track line enables the tail end to block the second light beam;
s62112, recording the position of the flange at the moment when the tail end blocks the second light beam, and recording the position as a nineteenth position;
s62113, setting a fifth trajectory line, wherein the trajectory line is located above the fourth trajectory line, and the fifth trajectory line is coincident with the orthographic projection of the fourth trajectory line on the working platform, and controlling the tip to be incapable of blocking the second light beam when the tool keeps the current posture and moves along the fifth trajectory line;
s62114, setting a sixth trajectory line so that the sixth trajectory line is located at the right middle of the fourth trajectory line and the fifth trajectory line in the vertical direction, controlling the tool to keep the current posture to move along the sixth trajectory line, and judging whether the tail end blocks the second light beam;
s62115, if the tail end can block the second light beam, continuously moving the translation track of the tool upwards from the sixth track line by bisection until the moment that the control system receives the blocking signal and switches to the receiving signal, and recording the position of the flange as a twentieth position, namely the eleventh position;
and if the tail end can not block the second light beam, continuously moving the translation track of the tool upwards from the fourth track line by bisection until the moment when the control system receives a blocking signal and switches to receive a receiving signal, recording the position of the flange, and marking as a twenty-first position, namely the eleventh position.
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