CN109916351B

CN109916351B - Method and device for acquiring TCP (Transmission control protocol) coordinates of robot

Info

Publication number: CN109916351B
Application number: CN201711330236.1A
Authority: CN
Inventors: 宫明波; 刘达
Original assignee: Beijing Baihui Weikang Technology Co Ltd
Current assignee: Beijing Baihui Weikang Technology Co Ltd
Priority date: 2017-12-13
Filing date: 2017-12-13
Publication date: 2020-09-08
Anticipated expiration: 2037-12-13
Also published as: CN109916351A; WO2019114629A1

Abstract

The embodiment of the invention provides a method and a device for acquiring a TCP (transmission control protocol) coordinate of a robot, which are implemented by calculating the square sum of errors between two coordinates after converting a coordinate of a point marked on a tool at the tail end of a mechanical arm under a mechanical arm coordinate system and a coordinate under a sensor coordinate system into the same coordinate system, comparing the absolute value of the difference of the square sum of the two times before and after the coordinate system with a set error threshold, and/or comparing the calculation times of the current coordinate of the point marked in the coordinate system at the tail end of the mechanical arm calculated according to the square sum of the coordinate errors and a least square method with a set calculation time threshold, when the absolute value of the difference of the square sum of the coordinate errors of the two times before and after the current coordinate system is less than or equal to the set error threshold and/or the calculation times exceeds the set calculation time threshold, setting the current coordinate of the marked point in the coordinate system at the tail end of the mechanical, the precision of calibrating the TCP coordinates is improved.

Description

Method and device for acquiring TCP (Transmission control protocol) coordinates of robot

Technical Field

The embodiment of the invention relates to the field of artificial intelligence, in particular to a method and a device for acquiring a TCP (transmission control protocol) coordinate of a robot.

Background

With the development of science and technology, the application field of the robot is more and more extensive. For robots in both the high-precision machining field and the surgical field, the task that needs to be performed requires a high precision.

Generally, when a high-precision machining robot and a surgical robot perform a work task, tools need to be additionally arranged on a mechanical arm of the robot to complete related work. Because the coordinate transformation relationship between the mechanical arm terminal coordinate system and the mechanical arm coordinate system can be calculated by the DH parameter, the error is small, and how to accurately obtain the coordinate of the Tool's own coordinate system origin (Tool Center Point, TCP) in the mechanical arm terminal coordinate system is a key factor affecting the working accuracy. Currently, the coordinates of TCP in the robot arm end coordinate system can be calculated or measured by combining the robot arm end coordinate system with the theoretical dimensions of the tool itself, which is called the theoretical coordinates of TCP. That is, when the tool is assembled to the end of the arm, the work task can only be performed using the theoretical coordinates of TCP.

However, a dimension error generally occurs in the process of machining a tool according to a design drawing, an assembly error may occur in the process of assembling the tool to the tail end of the mechanical arm, a deformation error may also occur when the tool is affected by the environment, a measurement error may also occur in the measurement process, and the like, these errors may cause a deviation between an actual coordinate of the TCP in a coordinate system of the tail end of the mechanical arm and a theoretical coordinate of the TCP, and if the TCP is calibrated by the theoretical coordinate of the TCP, an error is inevitably generated between the position of the calibrated TCP and the actual TCP position, thereby affecting the working accuracy of the robot.

Disclosure of Invention

One of the technical problems to be solved by the embodiments of the present application is to provide a method and an apparatus for obtaining a TCP coordinate of a robot, where an error generated by a coordinate of a point marked on a tool at a robot arm end of the robot in a coordinate system at the robot arm end is controlled within a small range by setting a calculation time threshold and/or an error threshold, so as to reduce a range of errors generated by the robot in a process of executing a work task, and further improve work accuracy of the robot.

In one aspect, an embodiment of the present application provides a method for acquiring a TCP coordinate of a robot, including:

s100: marking a point on a tool at the end of the robot arm which can be recognized by a sensor as a TCP, setting theoretical coordinates of the TCP as current coordinates of the marked point in a coordinate system at the end of the robot arm, setting a calculation time threshold and initializing the calculation time to 0, and/or setting an error threshold and initializing f (TCP)_x,y,z)_pastIs 0;

s200: obtaining M positions for establishing a coordinate conversion relation between a mechanical arm coordinate system and a sensor coordinate system and N positions for acquiring errors according to the movement of the marked point in a sensor identification range, wherein at least three positions which are not collinear are obtained from the M positions, M is an integer, M is not less than 3, N is an integer, and N is not less than 1;

s300: according to the coordinate conversion relation between the current coordinates of the marked point in the tail end coordinate system of the mechanical arm and the tail end coordinate system and the mechanical arm coordinate system, the coordinates of the marked point in the sensor coordinate system, and the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system established by utilizing the M positionsThe sum of the squares f of the coordinate errors of the marked points at the N positions is obtained (TCP)_x,y,z)_now。

S400: when | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastExecuting S600 when | is less than or equal to the error threshold and/or the calculation times are more than or equal to the calculation times threshold; otherwise, add 1 to the count and/or add f (TCP)_x,y,z)_nowAssigned to f (TCP)_x,y,z)_pastAnd then S500 is performed.

S500: according to f (TCP)_x,y,z)_nowObtaining the coordinates of the marked point in the terminal coordinate system of the mechanical arm by a least square method, taking the obtained coordinates as the current coordinates of the marked point in the terminal coordinate system of the mechanical arm, and executing S300;

s600: and taking the current coordinates of the marked point in the coordinate system of the tail end of the mechanical arm as the actual coordinates of the TCP.

Optionally, the step of establishing a coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system by using the M positions includes:

combining the coordinate conversion relation between the mechanical arm tail end coordinate system and the mechanical arm coordinate system corresponding to the M positions with the current coordinate of the marked point in the mechanical arm tail end coordinate system to obtain M coordinates of the marked point in the mechanical arm coordinate system;

and obtaining the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system according to the M coordinates of the marked points in the mechanical arm coordinate system and the coordinates of the marked points in the sensor coordinate system.

Optionally, the square sum f of the coordinate errors of the marked point at the N positions (TCP) is obtained according to the coordinate conversion relationship between the current coordinate of the marked point in the robot arm end coordinate system and the robot arm coordinate system, the coordinate of the marked point in the sensor coordinate system, and the coordinate conversion relationship between the robot arm coordinate system and the sensor coordinate system established by using the M positions (TCP)_x,y,z)_nowComprises the following steps:

according to the markThe current coordinate of the point in the coordinate system of the tail end of the mechanical arm and the coordinate conversion relation between the coordinate system of the tail end of the mechanical arm and the coordinate system of the mechanical arm are obtained, and the coordinate R of the marked point in the coordinate system of the mechanical arm is obtained_i，

According to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system, the coordinate R of the marked point in the mechanical arm coordinate system_iConverting to a sensor coordinate system to obtain a coordinate R'_i，

Comparison of the coordinates R'_iCoordinates C of the marked point in the sensor coordinate system_iThe sum of the squares of the coordinate errors of the marked points at the N positions is obtained, or,

obtaining the coordinate R of the marked point in the mechanical arm coordinate system according to the current coordinate of the marked point in the mechanical arm tail end coordinate system and the coordinate conversion relation between the mechanical arm tail end coordinate system and the mechanical arm coordinate system_i；

According to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system, the coordinate C of the marked point in the sensor coordinate system_iConverting to a mechanical arm coordinate system to obtain a coordinate C'_i，

Comparison of coordinate C'_iCoordinate R of marked point in mechanical arm coordinate system_iAnd obtaining the square sum of coordinate errors of the marked point at N positions, wherein 1 ≦ i ≦ N.

Optionally according to f (TCP)_x,y,z)_nowAnd the step of obtaining the coordinate of the marked point under the terminal coordinate system of the mechanical arm by a least square method comprises the following steps:

according to f (TCP)_x,y,z)_nowAnd obtaining the coordinates of the marked point under the terminal coordinate system of the mechanical arm by a nonlinear least square method.

Optionally, the step of obtaining the sum of squares of the coordinate errors of the marked point at the N positions is:

calculating a coordinate R 'at each of the N positions'_iCoordinates on each coordinate axis and coordinates C_iThe sum of squares of differences of coordinates on the respective coordinate axes;

adding the sum of the squares of the differences obtained at each of the N positions to obtain the sum of the squares of the coordinate errors of the marked point at the N positions, or,

calculating coordinates C 'at each of the N positions'_iCoordinates on each coordinate axis and coordinates R_iThe sum of squares of differences of coordinates on the respective coordinate axes;

and adding the square sums of the difference values obtained at each of the N positions to obtain the square sum of the coordinate errors of the marked point at the N positions.

Optionally, said according to f (TCP)_x,y,z)_nowAnd the calculation formula of the marked point coordinate under the mechanical arm tail end coordinate system obtained by the least square method is as follows:

on the other hand, the embodiment of the present application further provides a device for acquiring a TCP coordinate of a robot, including:

a marking TCP and setting threshold module, which is used for marking one point on the tool at the tail end of the mechanical arm, which can be identified by the sensor, as TCP, setting the theoretical coordinate of the TCP as the current coordinate of the marked point in the coordinate system at the tail end of the mechanical arm, setting a calculation time threshold and initializing the calculation time to be 0, and/or setting an error threshold and initializing f (TCP)_x,y,z)_pastIs 0;

the position acquisition module is used for acquiring M positions for establishing a coordinate conversion relation between a mechanical arm coordinate system and a sensor coordinate system and N positions for acquiring errors according to the movement of the marked point in the sensor identification range, wherein at least three positions which are not collinear are arranged in the M positions, M is an integer and is not less than 3, N is an integer and is not less than 1;

a coordinate error square sum obtaining module for marking the current coordinate of the marked point in the mechanical arm tail end coordinate system and the coordinate conversion relation between the mechanical arm tail end coordinate system and the mechanical arm coordinate systemCoordinates of the point in a sensor coordinate system and a coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system established by the M positions are utilized to obtain the square sum f (TCP) of coordinate errors of the marked point in the N positions_x,y,z)_now；

A threshold comparison module for comparing | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastThe magnitude of the | and the error threshold value, the magnitude of the comparison calculation times and the magnitude of the calculation time threshold value are compared, and the comparison result is sent to the data processing module and/or the actual coordinate setting module;

a data processing module for processing the data when the number of times of calculation is less than the threshold number of times of calculation and/or | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastIf | is greater than the error threshold, adding 1 to the number of calculations and/or obtaining f (TCP) from the threshold comparison module_x,y,z)_nowAssigned to f (TCP)_x,y,z)_past；

A coordinate calculation module for calculating a coordinate according to f (TCP) in the data processing module_x,y,z)_nowCalculating the coordinates of the marked point under the terminal coordinate system of the mechanical arm by a least square method, and sending the obtained coordinates to a square sum acquisition module of a coordinate error;

an actual coordinate setting module for setting the actual coordinate when the number of times of calculation is greater than or equal to a threshold number of times of calculation and/or | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastAnd when the | is less than or equal to the error threshold, taking the current coordinate of the marked point in the terminal coordinate system of the mechanical arm as the actual coordinate of the TCP.

Optionally, the module for obtaining a square sum of coordinate errors further comprises: and the coordinate conversion relation establishing module is used for combining the coordinate conversion relation between the mechanical arm tail end coordinate system and the mechanical arm coordinate system corresponding to the M positions with the current coordinate of the marked point in the mechanical arm tail end coordinate system to obtain M coordinates of the marked point in the mechanical arm coordinate system, and obtaining the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system according to the M coordinates of the marked point in the mechanical arm coordinate system and the coordinate of the marked point in the sensor coordinate system.

Optionally, the module for obtaining a square sum of coordinate errors further comprises: a coordinate determination module for obtaining the coordinate R of the marked point in the mechanical arm coordinate system according to the current coordinate of the marked point in the mechanical arm end coordinate system and the coordinate conversion relation between the mechanical arm end coordinate system and the mechanical arm coordinate system_i；

A coordinate conversion module for converting the coordinate R of the marked point in the mechanical arm coordinate system according to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system_iConverting the coordinate into a sensor coordinate system to obtain a coordinate R_iOr C coordinates for marking points in the sensor coordinate system based on the coordinate conversion relationship between the robot arm coordinate system and the sensor coordinate system_iConverting the coordinate system of the mechanical arm to obtain a coordinate C_i′；

A coordinate comparison module for comparing the coordinates R_i' coordinate C with marked point in sensor coordinate system_iThe sum of the squares of the coordinate errors of the marked points at the N positions is obtained or used for comparing the coordinates C_i' coordinate R of marked point in mechanical arm coordinate system_iAnd obtaining the square sum of coordinate errors of the marked point at N positions, wherein 1 ≦ i ≦ N.

Optionally, the coordinate calculation module is specifically configured to calculate the coordinate according to f (TCP)_x,y,z)_nowAnd obtaining the coordinates of the marked point under the terminal coordinate system of the mechanical arm by a nonlinear least square method.

Optionally, the coordinate comparison module is specifically configured to calculate a coordinate R 'at each of the N positions'_iCoordinates on each coordinate axis and coordinates C_iThe sum of squares of differences of coordinates on the respective coordinate axes;

adding the square sums obtained at each of the N positions to obtain the square sum of the coordinate errors of the marker point at the N positions, or,

calculating coordinates C 'at each of the N positions'_iOn respective coordinate axesCoordinates and coordinates R_iThe sum of squares of differences of coordinates on the respective coordinate axes;

and adding the square sums obtained at each of the N positions to obtain the square sum of the coordinate errors of the marked point at the N positions.

Optionally, the calculation formula of the coordinate of the marked point in the coordinate system of the end of the robot arm obtained in the coordinate calculation module is as follows:

as can be seen from the above technical solutions, according to the method and apparatus for acquiring TCP coordinates of a robot provided in the embodiments of the present application, coordinates of a point marked on a tool at a terminal of a robot arm in a robot arm coordinate system and coordinates of the point marked in a sensor coordinate system are converted into the same coordinate system, a sum of squares of coordinate errors of the two coordinates converted into the same coordinate system is calculated, an absolute value of a difference between the sum of squares of two times before and after the coordinate error is compared with a set error threshold, when the absolute value of the difference between the sum of squares is less than or equal to the set error threshold, a current coordinate of the marked point in the robot arm terminal coordinate system is taken as an actual coordinate of the TCP, or when the number of calculation times of a current coordinate of the marked point in the robot arm terminal coordinate system calculated by using a least square method according to the sum of the coordinate errors exceeds the set calculation times threshold, the method comprises the steps of setting the current coordinate of a marked point in a coordinate system at the tail end of a mechanical arm as the actual coordinate of a TCP (transmission control protocol), or setting the current coordinate of the marked point in the coordinate system at the tail end of the mechanical arm as the actual coordinate of the TCP when the absolute value of the difference of the square sum of coordinate errors of two times before and after the marked point is smaller than or equal to a set error threshold and the calculation times exceed a set calculation time threshold.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the embodiments of the present invention, and it is also possible for a person skilled in the art to obtain other drawings based on the drawings.

Fig. 1 is a schematic flowchart of a method for acquiring TCP coordinates by a robot according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of an apparatus for acquiring a TCP coordinate by a robot according to an embodiment of the present disclosure;

fig. 3 is a schematic diagram of a robot arm and a sensor provided in an embodiment of the present application.

Detailed Description

Of course, it is not necessary for any particular embodiment of the invention to achieve all of the above advantages at the same time.

In order to make those skilled in the art better understand the technical solutions in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments obtained by a person skilled in the art based on the embodiments of the present invention shall fall within the scope of the protection of the embodiments of the present invention.

Aiming at the problem that a Tool coordinate system origin (TCP) obtained by combining a mechanical arm end coordinate system with theoretical dimensions of the Tool itself through calculation or measurement in the prior art may have a large error between coordinates in the mechanical arm end coordinate system and actual coordinates of the TCP, an embodiment of the present application provides a method for obtaining coordinates of the TCP of a robot, as shown in fig. 1, including steps S100 to S600, specifically:

step S100: marking the end of a robotic armIs a TCP and sets the theoretical coordinates of the TCP as the current coordinates of the marked point in the robot arm end coordinate system, sets a count threshold and initializes the count to 0, and/or sets an error threshold and initializes f (TCP)_x,y,z)_pastThe value of (d) is 0.

In practice, a point is found on the tool at the end of the robot that can be identified by the sensor, or a point is selected from a plurality of points on the tool at the end of the robot that can be identified by the sensor, and this point is marked as TCP. It should be noted that, when the sensor is a camera, the marked point can be set as an optical mark point; when the sensor is an electromagnetic sensor, the marked points can be set as electromagnetic mark points; when the sensor is an ultrasonic probe, the marked points can be set as ultrasonic marking points; when the sensor is an infrared sensor, the marked points can be set as infrared marked points, or when the sensor is other types of sensors, the marked points corresponding to other types of sensors can be set. And the actual coordinates of the TCP in the robot arm end coordinate system are not determined in step S100, the embodiment of the present application determines the actual coordinates of the TCP according to the marked point. The theoretical coordinate of the TCP can be obtained by using a measuring tool or according to a rough calibration algorithm according to the theoretical size of the tool and the terminal coordinate system of the mechanical arm.

It should be noted that, in the embodiment of the present application, the calculation times may be initialized and a calculation time threshold may be set, and f (TCP) may be set_x,y,z)_pastThe error threshold is set by initializing, only the number of times of calculation may be set by initializing, or only f (TCP) may be set_x,y,z)_pastInitialize and set an error threshold, where f (TCP)_x,y,z)_pastRepresenting the error of the previous calculation. The threshold value of the number of calculations and the threshold value of the error are used as the end conditions of the coordinate calculation loop used when the actual coordinates of the TCP are set, that is, only the threshold value of the number of calculations may be used as the end conditions of the loop,the calculation number threshold and the error threshold may be used as the end condition of the loop.

In the actual operation process, the embodiment of the application sets the calculation time threshold and initializes the calculation time to 0, and/or sets the error threshold and initializes f (TCP)_x,y,z)_pastThe value of (d) is 0.

Step S200: and obtaining M positions for establishing a coordinate conversion relation between a mechanical arm coordinate system and a sensor coordinate system and N positions for acquiring errors according to the movement of the marked point in the sensor identification range, wherein at least three positions which are not collinear are obtained from the M positions, M is an integer, M is not less than 3, N is an integer, and N is not less than 1.

Specifically, a plurality of positions of the marked point within the sensor recognition range can be obtained according to the movement of the marked point within the sensor recognition range, where M positions for establishing a coordinate conversion relationship between the robot arm coordinate system and the sensor coordinate system, where M is an integer and M ≧ 3, and N positions for collecting errors can be obtained, where M positions are at least three non-collinear positions, and M is an integer and M ≧ 3, and simultaneously, N positions different from M positions for collecting errors between the coordinates of the marked point in the robot arm coordinate system and the coordinates in the sensor coordinate system, that is, coordinate errors obtained by converting the coordinates of the marked point in the robot arm coordinate system and the coordinates in the sensor coordinate system into the same coordinate system, are obtained according to the movement of the marked point within the sensor recognition range, n is an integer, and N ≧ 1.

Step S300: obtaining the square sum f (TCP) of the coordinate error of the marked point on the N positions according to the coordinate conversion relation between the current coordinate of the marked point in the mechanical arm tail end coordinate system and the mechanical arm coordinate system, the coordinate of the marked point in the sensor coordinate system and the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system established by the M positions_x,y,z)_now。

Specifically, the manner of implementing step S300 is: establishing a coordinate conversion relation between a mechanical arm coordinate system and a sensor coordinate system according to the current coordinate of the marked point in the mechanical arm tail end coordinate system, the coordinate conversion relation between the M mechanical arm tail end coordinate systems and the mechanical arm coordinate systems when the marked point is located at the M positions, and the M coordinates in the sensor coordinate system when the marked point is located at the M positions;

and obtaining the square sum f (TCP) of the coordinate errors of the marked points on the N positions according to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system_x,y,z)_now。

The step of utilizing the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system established by the M positions comprises the following steps:

Namely, the marked points are positioned in the coordinate conversion relation between the M mechanical arm terminal coordinate systems and the mechanical arm coordinate systems corresponding to the M positions (namely when the marked points are positioned at a certain position, the mechanical arms have a pose corresponding to the pose, the coordinate conversion relation between the mechanical arm terminal coordinate system and the mechanical arm coordinate system corresponding to the pose can be obtained through a DH parameter, if the marked points are positioned at the M positions, the coordinate conversion relation between the M mechanical arm terminal coordinate systems and the mechanical arm coordinate systems corresponding to the pose exists), and the marked points are combined with the current coordinates of the marked points in the mechanical arm terminal coordinate system to obtain M coordinates of the marked points in the mechanical arm coordinate system;

and obtaining the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system according to the M coordinates of the marked point in the mechanical arm coordinate system and the M coordinates of the marked point in the sensor coordinate system corresponding to the M positions.

Specifically, M positions for establishing a coordinate conversion relationship between the robot arm coordinate system and the sensor coordinate system may be obtained first according to movement of the marked point (i.e., the TCP in S100) within the sensor identification range, where M is an integer greater than or equal to 3, and there are at least three non-collinear positions among the M positions; since the coordinate transformation relationship between the robot arm end coordinate system and the robot arm coordinate system can be calculated by the DH parameter, according to the schematic diagram of the robot arm and the sensor shown in fig. 3, the coordinate transformation relationship between the robot arm end coordinate system and the robot arm coordinate system is combined with the current coordinates of the marked point in the robot arm end coordinate system, so as to obtain M coordinates of the marked point in the robot arm coordinate system at M positions, and since the sensor can recognize the marked point, the marked point has a corresponding coordinate in the sensor coordinate system at each of the M positions, and further, according to the coordinates of the marked point in the robot arm coordinate system and the coordinates in the sensor coordinate system at each of the M positions, the method of the prior art for obtaining the transformation relationship between the two coordinate systems by using the coordinates of the same point in the two coordinate systems is applied, the coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system can be obtained.

Preferably, M has a value of 3 or M has a value of 4. When the value of M is 3, the 3 positions of the marked point in the real space are non-collinear positions; when the value of M is 4, the 4 positions of the marked point in the real space may be non-coplanar positions.

When the value of M is 3, the process of establishing the coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system using the M positions may be:

assuming that when the marked point is obtained by moving the mechanical arm at three non-collinear positions in the actual space, the mechanical arm is in three poses, i.e., pose 1, pose 2 and pose 3.

When the mechanical arm moves to the pose 1, the coordinate conversion relation between the mechanical arm terminal coordinate system and the mechanical arm coordinate system when the mechanical arm is located at the pose 1 and the coordinate p1 of the mechanical arm terminal coordinate system origin under the mechanical arm coordinate system can be obtained through the DH parameters, the theoretical coordinate of the TCP in the coordinate system of the tail end of the mechanical arm can be obtained through the processing drawing of the tool, and is recorded as the current coordinate t1, therefore, the coordinates of the current TCP in the coordinate system of the robot arm are represented by p1+ t1 (it should be noted that, the coordinates of the current TCP in the coordinate system of the robot arm are not added to the coordinates of p1 and the coordinates of t1, and the expression "p 1+ t 1" is merely used here to explain the coordinates of the current TCP in the coordinate system of the robot arm when the robot arm is in pose 1, and the same is true in the following similar descriptions), namely, the coordinates p1+ t1 of the point marked when the robot arm is in the pose 1 in the robot arm coordinate system can be obtained. By the sensor recognizing the marked point, the coordinate s1 of the marked point in the sensor coordinate system when the robot arm is in the pose 1 can also be obtained.

When the mechanical arm moves to the pose 2, the coordinate conversion relation between the terminal coordinate system of the mechanical arm and the coordinate system of the mechanical arm when the current mechanical arm is located at the pose 2 and the coordinate p2 of the origin of the terminal coordinate system of the mechanical arm under the coordinate system of the mechanical arm can be obtained through the DH parameters, and the obtained coordinate t1 of the TCP in the terminal coordinate system of the mechanical arm represents the coordinate of the current TCP under the coordinate system of the mechanical arm by p2+ t1, namely the coordinate p2+ t1 of the point marked when the mechanical arm is located at the pose 2 under the coordinate system of the mechanical arm is obtained. By the sensor recognizing the marked point, the coordinate s2 of the marked point in the sensor coordinate system when the robot arm is in the pose 2 can also be obtained.

When the mechanical arm moves to the pose 3, the coordinate conversion relation between the tail end coordinate system of the mechanical arm and the mechanical arm coordinate system when the current mechanical arm is located at the pose 3, the coordinate p3 of the origin of the tail end coordinate system of the mechanical arm in the mechanical arm coordinate system and the obtained coordinate t1 of the TCP in the tail end coordinate system of the mechanical arm can be obtained through the DH parameters, so that the coordinate p3+ t1 of the current TCP in the mechanical arm coordinate system is represented by p3+ t1, and the coordinate p3+ t1 of the marked point in the mechanical arm coordinate system when the mechanical arm is located at the pose 3 is obtained. By the sensor recognizing the marked point, the coordinate s3 of the marked point in the sensor coordinate system when the robot arm is in the pose 3 can also be obtained.

In the embodiment of the application, the coordinate conversion relationship between the robot arm coordinate system and the sensor coordinate system can be established by utilizing p1+ t1 and s1, p2+ t1 and s2, and p3+ t1 and s3, namely the coordinates of the three non-collinear points in the robot arm coordinate system and the coordinates in the sensor coordinate system respectively.

When the value of M is 4, the process of establishing the coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system using M positions may be:

assuming that the robot arm is in four positions, namely pose 1, pose 2, pose 3 and pose 4, when four non-coplanar positions of the marked point in the actual space are obtained by moving the robot arm.

Obtaining coordinates of four non-coplanar points under a mechanical arm coordinate system and coordinates of four non-coplanar points under a sensor coordinate system respectively in the same way as when the value of M is 3, and establishing an affine coordinate system by taking one of the four non-coplanar points as an origin and a connecting line of the origin and the other three points as coordinate axes; establishing a first spatial relationship between a sensor coordinate system and an affine coordinate system according to coordinates of each point in the four non-coplanar points in the sensor coordinate system and the affine coordinate system, and establishing a second spatial relationship between a mechanical arm coordinate system and the affine coordinate system according to coordinates of each point in the four non-coplanar points in the mechanical arm coordinate system and the affine coordinate system; and determining the conversion relation between the mechanical arm coordinate system and the sensor coordinate system according to the first spatial relation and the second spatial relation.

Alternatively, it is also possible to move the marked point to P positions within the sensor identification range, where P is an integer equal to or greater than 4, then select M positions for establishing a coordinate conversion relationship between the sensor coordinate system and the robot arm coordinate system from the P positions, and use the remaining N positions different from the M positions for acquiring errors, that is, P + M.

It should be noted that when the marked point is moved to P positions, M positions or N positions within the sensor range, a moving program or a moving path may be set for the robot arm, so that the robot arm automatically moves within the sensor identification range, and other existing methods may be adopted, which is not specifically limited in the embodiment of the present application.

In addition, the square sum f of the coordinate errors of the marked point at the N positions is obtained (TCP)_x,y,z)_nowThe steps of (1) may be:

obtaining the coordinate R of the marked point in the mechanical arm coordinate system according to the current coordinate of the marked point in the mechanical arm tail end coordinate system and the coordinate conversion relation between the mechanical arm tail end coordinate system and the mechanical arm coordinate system_i(ii) a Then, according to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system, the coordinate R of the marked point in the mechanical arm coordinate system is obtained_iConverting to a sensor coordinate system to obtain a coordinate R'_i(ii) a Comparison of the coordinates R'_iCoordinates C of the marked point in the sensor coordinate system_i(coordinate C)_iObtained by the sensor identifying the marked point), the sum of the squares of the coordinate errors of the marked point at N positions is obtained, where 1 ≦ i ≦ N.

Since the current coordinates of the marked point in the robot arm end coordinate system are known, the coordinate transformation relationship between the robot arm end coordinate system and the robot arm coordinate system of the marked point at any one of the N positions is also known (which can be obtained by DH parameters), so that the coordinates R of the marked point in the robot arm coordinate system can be obtained_i(ii) a The coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system can be obtained by utilizing the M positions, so that the coordinate R of the marked point in the mechanical arm coordinate system can be obtained_iConverting the coordinate into a sensor coordinate system to obtain a coordinate R_i'; in addition, when the marked point is at any one position of N positions, the marked point can be identified by the sensor, and the coordinate C of the marked point in the sensor coordinate system can be obtained_i(ii) a Only then to compare the coordinates R_i' coordinate C with marked point in sensor coordinate system_iIt can be found that the marked point is in each of the N positionsThe coordinate error over the positions, and thus the sum of the squares of the coordinate errors over the N positions of the marked point.

The square sum f of the coordinate errors of the marked points at the N positions is obtained (TCP)_x,y,z)_nowThe step (2) may further be:

obtaining the coordinate R of the marked point in the mechanical arm coordinate system according to the current coordinate of the marked point in the mechanical arm tail end coordinate system and the coordinate conversion relation between the mechanical arm tail end coordinate system and the mechanical arm coordinate system_i(ii) a According to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system, the coordinate C of the marked point in the sensor coordinate system_iConverting to a mechanical arm coordinate system to obtain a coordinate C'_i(ii) a Comparison of coordinate C'_iCoordinate R of marked point in mechanical arm coordinate system_iAnd obtaining the square sum of coordinate errors of the marked point at N positions, wherein 1 ≦ i ≦ N.

Optionally, the coordinates R 'are compared'_iAnd the coordinate C_iThe step of obtaining the sum of squares of the coordinate errors of the marked points at the N positions is:

calculating a coordinate R 'at each of the N positions'_iCoordinates on each coordinate axis and coordinates C_iThe square sum of the differences of the coordinates on the corresponding coordinate axes;

calculating coordinates C 'at each of the N positions'_iCoordinates on each coordinate axis and coordinates R_iThe square sum of the differences of the coordinates on the corresponding coordinate axes;

Specifically, if the current coordinates in the robot arm end coordinate system according to the marked point are related to the coordinate transformation between the robot arm end coordinate system and the robot arm coordinate systemSystem, obtaining the coordinates R of the marked point in the robot coordinate system_i(x_i，y_i，z_i) According to the conversion relation between the mechanical arm coordinate system and the sensor coordinate system, the coordinate R is converted into the coordinate R_i(x_i，y_i，z_i) Converting to a sensor coordinate system to obtain a coordinate R'_i(x′_i,y′_i,z′_i) Will be the coordinate R'_i(x′_i,y′_i,z′_i) Coordinates C of the marked point in the sensor coordinate system_i(x_Ci，y_Ci，z_Ci) By comparison, the sum of the squares of the coordinate errors of the marked points at the current position error can be obtained_i＝Δx_i ²+Δy_i ²+Δz_i ²＝(x′_i-x_Ci)²+(y′_i-y_Ci)²+(z′_i-z_Ci)²。

Or according to the conversion relation between the mechanical arm coordinate system and the sensor coordinate system, the coordinate C of the marked point in the sensor coordinate system_i(x_ci，y_ci，z_ci) Converting to a mechanical arm coordinate system to obtain a coordinate C'_i(x′_ci,y′_ci,z′_ci) Then coordinate C'_i(x′_ci,y′_ci,z′_ci) Coordinate R of marked point in mechanical arm coordinate system_i(x_i，y_i，z_i) The comparison results in the square sum error of the coordinate error of the marked point at the current position_i＝Δx_i ²+Δy_i ²+Δz_i ²＝(x_i-x′_ci)²+(y_i-y′_ci)²+(z_i-z′_ci)²。

If the value of N is 2, 2 positions for acquiring errors are obtained according to the movement of the marked point in the sensor identification range, and the example of converting the coordinate of the marked point in the robot arm coordinate system to the coordinate in the sensor coordinate system is described, and the marked point is on the robot arm coordinate systemThe coordinates of the arm coordinate system are denoted as R₁(x₁，y₁，z₁) And R₂(x₂，y₂，z₂) And the coordinates in the sensor coordinate system are denoted as C₁(x_C1，y_C1，z_C1) And C₂(x_C2，y_C2，z_C2) According to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system, R is converted₁And R₂Converting to a sensor coordinate system to obtain R'₁(x′₁，y′₁，z′₁) And R'₂(x′₂，y′₂，z′₂) Will be the coordinate R'₁And C₁，R′₂And C₂Comparing to obtain the square sum of coordinate errors when N is 2

Summarizing the above, the sum of squares of the coordinate errors of the marked points at the positions used for error acquisition

Step S400: when | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastWhen | is less than or equal to the error threshold and/or the calculation times are greater than or equal to the calculation times threshold, executing step S600; otherwise, add 1 to the count and/or add f (TCP)_x,y,z)_nowAssigned to f (TCP)_x,y,z)_pastThen step S500 is performed.

Step S500: according to f (TCP)_x,y,z)_nowAnd obtaining the coordinates of the marked point in the terminal coordinate system of the mechanical arm by a least square method, taking the obtained coordinates as the current coordinates of the marked point in the terminal coordinate system of the mechanical arm, and executing the step S300.

In the embodiment of the present application, step S400 and step S500 are explained in combination. When in useFirst time on | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastWhen | is compared with the error threshold and/or the calculation times are compared with the calculation times threshold for the first time, the coordinates of the TCP are theoretical coordinate values of the marked point in the robot arm end coordinate system, and f (TCP)_x,y,z)_pastThe value of (d) is an initialized value, i.e., 0, and the number of calculations is also an initialized value, likewise 0. Therefore, when first pair | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastWhen | is compared, | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastI is exactly | f (TCP)_x,y,z)_nowL. When the calculation in step S500 returns to step S300, the current coordinates of the marked point in the coordinate system of the end of the robot arm are already according to f (TCP)_x,y,z)_nowCoordinates obtained by combining the least square method are obtained, so that after the coordinates of the marked point in the robot arm end coordinate system obtained by the calculation in the step S500 are substituted into the step S300 (that is, the current coordinates of the marked point in the robot arm end coordinate system are updated), new coordinates of the new marked point in the robot arm coordinate system are obtained, then, according to the new coordinates of the marked point in the robot arm coordinate system and the coordinates of the marked point in the sensor coordinate system, a new coordinate transformation relation between the robot arm coordinate system and the sensor coordinate system is obtained, further according to the new coordinate transformation relation, the sum of squares of new coordinate errors of the marked point at the N positions is obtained, and then the sum of squares of the new coordinate errors is assigned to f (TCP)_x,y,z)_nowF (TCP) obtained previously_x,y,z)_nowAssigned to f (TCP)_x,y,z)_pastThen use the new f (TCP)_x,y,z)_nowCombined with the least squares calculation of another new coordinate … … of the marked point in the robot arm tip coordinate system, so on, until | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastAnd | is less than or equal to the error threshold and/or the calculation times are greater than or equal to the calculation times threshold.

In the embodiment of the present application, the end condition for triggering the above-mentioned cycle may have three determination manners:

first, the number of calculations is equal to or greater than a threshold number of calculations. The number of times of calculation referred to herein is based on f (TCP)_x,y,z)_nowCalculating the number of times of the marked point in the coordinate system at the tail end of the mechanical arm by combining a least square method, and when the number of times is more than or equal to the threshold value of the calculation number set in the step S100, meeting the triggering condition and ending the circulation;

second, | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastI is less than or equal to the error threshold, that is, the absolute value of the difference between the sum of squares of the coordinate errors of the two marked points at the position for acquiring the error is less than or equal to the error threshold set in step S100, for example, if the error threshold set in step S100 is 10^-5Then when | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_past|<10^-5If so, ending the loop and executing the step S600;

thirdly, the method simultaneously satisfies the condition that the calculation times are more than or equal to the threshold sum of the calculation times | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastAnd | is less than or equal to the error threshold.

When any one of the above three determination methods is adopted and the determination condition is satisfied, step S600 is executed: and taking the current coordinates of the marked point in the coordinate system of the tail end of the mechanical arm as the actual coordinates of the TCP.

When the first judgment mode is not satisfied, adding 1 to the number of times of calculation, namely adding 1 to the current value of the number of times of calculation, and substituting the value of the number of times of calculation into judgment in subsequent cycle judgment;

when the second judgment mode is not satisfied, f (TCP) is set_x,y,z)_nowAssigned to f (TCP)_x,y,z)_past；

When the third judgment mode is not satisfied, 1 is added to the number of times of calculation and f (TCP) is added_x,y,z)_nowAssigned to f (TCP)_x,y,z)_past。

Optionally according to f (TCP)_x,y,z)_nowCombining least squaresThe method for obtaining the coordinates of the marked point under the terminal coordinate system of the mechanical arm preferably comprises the following steps:

In the embodiment of the present application, according to f (TCP)_x,y,z)_nowAnd a nonlinear least squares method, and the calculation formula for obtaining the coordinates of the marked point under the mechanical arm tail end coordinate system can be:

in the formula, TCP is a coordinate to be solved of a marked point in a coordinate system at the tail end of the mechanical arm, and the TCP is embodied in a matrix form in the formula;

a matrix representing the homogeneous coordinates (calculated by formula, i.e. by combining the coordinates in the robot arm coordinate system with the coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system established by using the M positions) of the marked point in the sensor coordinate system at one of the N positions, wherein

A conversion relation matrix between a mechanical arm coordinate system and a sensor coordinate system is obtained by combining the marked points with the coordinates to be solved of the TCP at the M positions,

when the marked point is combined with the coordinate to be solved of the TCP and located at one of N positions, a homogeneous coordinate matrix is formed under a mechanical arm coordinate system;

a homogeneous coordinate (coordinate value actually acquired by the sensor) matrix in a sensor coordinate system when the marked point is located at one of N positions; e is a unitAnd (4) matrix.

Wherein the content of the first and second substances,

a sensor coordinate system point set matrix which needs to be acquired when the conversion relation between the mechanical arm coordinate system and the sensor coordinate system is established by utilizing M positions, in particular to

In the formula x_cam，y_cam，z_camIndicating the coordinates of the marked point on three coordinate axes in the sensor coordinate system at any one of the M positions, where x is_camM，y_camM，z_camMThe corner marks of (1) respectively correspond to one of the M positions.

Wherein the content of the first and second substances,

the method is characterized in that a mechanical arm coordinate system point set matrix which needs to be acquired when a conversion relation between a mechanical arm coordinate system and a sensor coordinate system is established by utilizing M positions, specifically speaking, the method is characterized in that

In the formula x_rbt，y_rbt，z_rbtWhen the marked point is at one of M positions, the coordinate of three coordinate axes in the robot arm coordinate system is at the origin of the robot arm end coordinate system, wherein x is_rbtM，y_rbtM，z_rbtMThe corner marks of (1) respectively correspond to one of the M positions.

Wherein the content of the first and second substances,

the matrix of the pose parameters of the mechanical arm when the marked point is at one of the N positions is obtained by the DH parameters of the mechanical arm and can be read from pose information recorded by the mechanical arm.

If the conversion relation between the mechanical arm coordinate system and the sensor coordinate system is established by the 4 positions to which the marked points move in the identification range of the sensor, the specific numerical values can be obtained after being brought in

Wherein 1 ≦ i ≦ N.

Based on the same inventive concept, as shown in fig. 2, an embodiment of the present application further provides an apparatus for acquiring a TCP coordinate of a robot, including:

a mark TCP and set threshold module 201 for marking a point on the tool at the end of the robot arm that can be recognized by the sensor as TCP, setting the theoretical coordinates of TCP as the current coordinates of the marked point in the robot arm end coordinate system, setting a count threshold and initializing count to 0, and/or setting an error threshold and initializing f (TCP)_x,y,z)_pastIs 0;

the position acquisition module 202 is configured to obtain M positions for establishing a coordinate conversion relationship between a mechanical arm coordinate system and a sensor coordinate system and N positions for acquiring errors according to movement of a marked point within a sensor identification range, where at least three of the M positions are non-collinear, M is an integer, M is ≧ 3, N is an integer, and N is ≧ 1;

a coordinate error square sum obtaining module 203, configured to obtain a square sum f (TCP) of coordinate errors of the marked point at the N positions according to a coordinate transformation relationship between a current coordinate of the marked point in a robot arm end coordinate system and the robot arm end coordinate system, a coordinate of the marked point in a sensor coordinate system, and a coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system established by using the M positions_x,y,z)_now；

A threshold comparison module 204 connected to the coordinate error square sum obtaining module 203 for comparing | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastMagnitude of | and error threshold and/or number of comparison calculationsAnd calculating the size of the time threshold, and sending the comparison result to the data processing module 205 and the actual coordinate setting module 207;

a data processing module 205 connected to the threshold comparison module 204 for determining whether the number of times of calculation is less than the threshold of the number of times of calculation and/or if (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastIf | is greater than the error threshold, adding 1 to the number of calculations and/or obtaining f (TCP) from the threshold comparison module_x,y,z)_nowAssigned to f (TCP)_x,y,z)_past；

A coordinate calculation module 206 connected to the data processing module 205 for calculating a coordinate according to f (TCP) in the data processing module 205_x,y,z)_nowCalculating the coordinates of the marked point in the terminal coordinate system of the mechanical arm by a least square method, and sending the obtained coordinates to a square sum acquisition module 203 of a coordinate error, so that the current coordinates of the marked point in the square sum acquisition module 203 in the terminal coordinate system of the mechanical arm are replaced;

an actual coordinate setting module 207 connected to the threshold comparison module 204 for setting the actual coordinate when the number of calculations is greater than or equal to the threshold of the number of calculations and/or | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastAnd when the | is less than or equal to the error threshold, taking the current coordinate of the marked point in the terminal coordinate system of the mechanical arm as the actual coordinate of the TCP.

In this embodiment, the marking TCP and setting threshold module 201, the position obtaining module 202, the square sum of coordinate error obtaining module 203, the threshold comparing module 204, the data processing module 205, the coordinate calculating module 206, and the actual coordinate setting module 207 may execute preferred embodiments of the foregoing method embodiments.

Further, in the apparatus for acquiring a TCP coordinate of a robot provided in the embodiment of the present application, the coordinate error square sum acquiring module 203 further includes a coordinate transformation relationship establishing module, configured to combine a coordinate transformation relationship between the robot arm end coordinate system and the robot arm coordinate system corresponding to the M positions with a current coordinate of the marked point in the robot arm end coordinate system to obtain M coordinates of the marked point in the robot arm coordinate system, and obtain a coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system according to the M coordinates of the marked point in the robot arm coordinate system and the coordinate of the marked point in the sensor coordinate system.

According to the embodiment of the application, the number of positions to which the marked points move in the sensor identification range for establishing the coordinate system conversion relationship is M, so that the coordinate conversion relationship between the M mechanical arm end coordinate systems and the mechanical arm coordinate systems exists, wherein at least three positions of the M positions are not collinear, M is an integer, M is not less than 3, N is an integer, and N is not less than 1.

The coordinate conversion relationship between the M mechanical arm terminal coordinate systems and the mechanical arm coordinate system is combined with the current coordinates of the marked points in the mechanical arm terminal coordinate system, so that the M coordinates of the marked points in the mechanical arm coordinate system can be obtained, and the coordinate conversion relationship between the mechanical arm coordinate system and the sensor coordinate system can be established by combining the M coordinates of the marked points in the sensor coordinate system.

Further, the coordinate error square sum obtaining module 203 obtains the coordinate error square sum through the coordinate determining module, the coordinate converting module and the coordinate comparing module. Wherein:

a coordinate determination module for obtaining the coordinate R of the marked point in the mechanical arm coordinate system according to the current coordinate of the marked point in the mechanical arm end coordinate system and the coordinate conversion relation between the mechanical arm end coordinate system and the mechanical arm coordinate system_i；

A coordinate conversion module for converting the coordinate R of the marked point in the mechanical arm coordinate system according to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system_iConverting the coordinate into a sensor coordinate system to obtain a coordinate R_i', or for use in connection with a robot armThe coordinate conversion relation between the coordinate system and the sensor coordinate system is realized by the coordinate C of the marked point in the sensor coordinate system_iConverting to a mechanical arm coordinate system to obtain a coordinate C'_i；

A coordinate comparison module for comparing the coordinates R'_iCoordinates C of the marked point in the sensor coordinate system_iThe sum of squares of the coordinate errors of the marked points at N positions is obtained or is used for comparing the coordinates C'_iCoordinate R of marked point in mechanical arm coordinate system_iAnd obtaining the square sum of coordinate errors of the marked point at N positions, wherein 1 ≦ i ≦ N.

Further, the coordinate calculation module is specifically adapted to calculate the coordinate according to f (TCP)_x,y,z)_nowAnd obtaining the coordinates of the marked point under the terminal coordinate system of the mechanical arm by a nonlinear least square method.

It should be noted that the coordinate calculation module 206 may also obtain the coordinates of the marked point in the coordinate system of the end of the robot arm by other methods, such as a linear least square method, which is not specifically limited in this embodiment, as long as the coordinates of the marked point in the coordinate system of the end of the robot arm can be accurately obtained.

Further, the coordinate comparison module is specifically configured to:

adding the sums of squares of the differences obtained at each of the N positions to obtain sums of squares of coordinate errors of the marker points at the N positions, or,

Further, the calculation formula of the coordinate of the marked point in the coordinate system of the end of the robot arm obtained in the coordinate calculation module 206 is as follows:

a matrix of homogeneous coordinates (formula-calculated coordinate values) in a sensor coordinate system representing the marked point at N positions, wherein

a homogeneous coordinate (coordinate value actually acquired by the sensor) matrix in a sensor coordinate system when the marked point is located at one of N positions; e is an identity matrix. Wherein the content of the first and second substances,

In the formula x_cam，y_cam，z_camIndicating that the marked point is in one of the M positions,coordinates on three coordinate axes in the sensor coordinate system, where x_camM，y_camM，z_camMThe corner marks of (1) respectively correspond to one of the M positions.

Wherein the content of the first and second substances,

Wherein the content of the first and second substances,

The device for acquiring the TCP coordinates of the robot provided in the embodiment of the present application may be disposed in the robot, may be disposed in another device other than the robot, or may be an independent device independent of another device.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a unit is merely a logical division, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately processed, or two or more units may be integrated into one unit. The integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.

The integrated unit implemented in the form of a software functional unit may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute some steps of the methods according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the embodiments of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A method for acquiring a robot TCP coordinate is characterized by comprising the following steps:

s300: obtaining the square sum f (TCP) of the coordinate error of the marked point on the N positions according to the coordinate conversion relation between the current coordinate of the marked point in the mechanical arm tail end coordinate system and the mechanical arm coordinate system, the coordinate of the marked point in the sensor coordinate system and the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system established by the M positions_x,y,z)_now；

S400: when | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastExecuting S600 when | is less than or equal to the error threshold and/or the calculation times are more than or equal to the calculation times threshold; otherwise, add 1 to the count and/or add f (TCP)_x,y,z)_nowAssigned to f (TCP)_x,y,z)_pastThen executing S500;

2. The method for acquiring the TCP coordinate of the robot, according to claim 1, wherein the step of establishing the coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system by using the M positions comprises the following steps:

3. The method for acquiring the TCP coordinate of the robot according to claim 1 or 2, wherein the square sum f (TCP) of the coordinate error of the marked point at the N positions is obtained according to the coordinate transformation relationship between the current coordinate of the marked point in the robot arm end coordinate system and the robot arm coordinate system, the coordinate of the marked point in the sensor coordinate system, and the coordinate transformation relationship between the robot arm coordinate system and the sensor coordinate system established by the M positions_x,y,z)_nowComprises the following steps:

obtaining the coordinate R of the marked point in the mechanical arm coordinate system according to the current coordinate of the marked point in the mechanical arm tail end coordinate system and the coordinate conversion relation between the mechanical arm tail end coordinate system and the mechanical arm coordinate system_i，

Comparison of the coordinates R'_iCoordinates C of the marked point in the sensor coordinate system_iGet the seating of the marked points in N positionsThe sum of the squares of the normalized errors, or,

4. Method for acquiring robot TCP coordinates according to claim 1, characterized by that, according to f (TCP)_x,y,z)_nowAnd the step of obtaining the coordinate of the marked point under the terminal coordinate system of the mechanical arm by a least square method comprises the following steps:

5. The method for acquiring the TCP coordinate of the robot as claimed in claim 3, wherein the step of obtaining the square sum of the coordinate errors of the marked points at N positions is:

calculating coordinates C 'at each of the N positions'_iCoordinates on each coordinate axis and coordinates R_iOf differences in coordinates on respective coordinate axesThe sum of squares;

6. Method for acquiring robot TCP coordinates according to claim 1, characterized in that, said method is according to f (TCP)_x,y,z)_nowAnd the calculation formula of the marked point coordinate under the mechanical arm tail end coordinate system obtained by the least square method is as follows:

wherein E is an identity matrix,

when the marked point is combined with the coordinate to be solved of the TCP and is positioned at one of N positions, a homogeneous coordinate matrix is formed under a mechanical arm coordinate system,

a homogeneous coordinate matrix in the sensor coordinate system when the marked point is located at one of the N positions,

indicating a homogeneous coordinate matrix in the sensor coordinate system for the marked point at one of the N positions.

7. An apparatus for acquiring robot TCP coordinates, the apparatus comprising:

marking TCP and setting threshold moduleA block for marking one point on the tool at the end of the robot arm which can be recognized by the sensor as TCP, setting the theoretical coordinates of TCP as the current coordinates of the marked point in the coordinate system at the end of the robot arm, setting a threshold value of the number of calculations and initializing the number of calculations to 0, and/or setting an error threshold value and initializing f (TCP)_x,y,z)_pastIs 0;

a coordinate error square sum obtaining module, configured to obtain a square sum f (TCP) of coordinate errors of the marked point at the N positions according to a coordinate conversion relationship between a current coordinate of the marked point in a robot arm end coordinate system and the robot arm coordinate system, a coordinate of the marked point in a sensor coordinate system, and a coordinate conversion relationship between the robot arm coordinate system and the sensor coordinate system established by using the M positions_x,y,z)_now；

A threshold comparison module for comparing | f (TCP)_x,y,z)_now-f(TCP_x,y,z)_pastI and the magnitude of the error threshold value and/or the magnitude of the comparison calculation times and the calculation time threshold value, and sending the comparison result to the data processing module and the actual coordinate setting module;

A coordinate calculation module for calculating a coordinate according to f (TCP) in the data processing module_x,y,z)_nowAnd calculating the coordinates of the marked point under the coordinate system of the tail end of the mechanical arm by a least square method, and calculating the coordinatesThe obtained coordinates are sent to a coordinate error square sum obtaining module;

8. The apparatus for acquiring the TCP coordinate of the robot according to claim 7, wherein the module for acquiring the square sum of the coordinate errors further comprises:

and the coordinate conversion relation establishing module is used for combining the coordinate conversion relation between the mechanical arm tail end coordinate system and the mechanical arm coordinate system corresponding to the M positions with the current coordinate of the marked point in the mechanical arm tail end coordinate system to obtain M coordinates of the marked point in the mechanical arm coordinate system, and obtaining the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system according to the M coordinates of the marked point in the mechanical arm coordinate system and the coordinate of the marked point in the sensor coordinate system.

9. The apparatus for acquiring the TCP coordinate of the robot according to claim 7 or 8, wherein the module for acquiring the square sum of the coordinate errors further comprises:

A coordinate conversion module for converting the coordinate R of the marked point in the mechanical arm coordinate system according to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system_iConverting to a sensor coordinate system to obtain a coordinate R'_iOr coordinates C of the marked point in the sensor coordinate system according to the coordinate conversion relation between the mechanical arm coordinate system and the sensor coordinate system_iSwitch over toObtaining a coordinate C 'in a mechanical arm coordinate system'_i；

10. Device for acquiring the coordinates of a robot TCP according to claim 7, characterized in that said coordinate calculation module is specifically configured to calculate the coordinates according to f (TCP)_x,y,z)_nowAnd obtaining the coordinates of the marked point under the terminal coordinate system of the mechanical arm by a nonlinear least square method.

11. The apparatus according to claim 9, wherein the coordinate comparison module is specifically configured to:

12. The device for acquiring the TCP coordinate of the robot according to claim 7, wherein the coordinate calculation module obtains the coordinate of the marked point in the robot arm end coordinate system according to the following formula:

，

wherein E is an identity matrix, and E is an identity matrix,