Industrial robot positioning accuracy detection device and method

Abstract

This invention discloses a device and method for detecting the positioning accuracy of an industrial robot. The detection device comprises a posture measurement mechanism, a positioning device, and a dual-feature mechanism. The posture measurement mechanism includes a sensor bracket and three laser sensors: an X-axis laser ranging sensor, a Y-axis laser ranging sensor, and a Z-axis laser ranging sensor. The positioning device comprises a mounting frame, a vertical plate, a straight rod, a magnetic ring encoder, and a connecting rod mechanism. The dual-feature mechanism comprises a Y-shaped connection mechanism, a spherical feature, and a cubic feature. By calculating the deviation of the robot's end position value and the deviation of the robot's end posture value, the invention achieves high-degree-of-freedom and high-precision position and posture measurement of the industrial robot's end.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial robot precision measurement, and in particular to an industrial robot positioning precision detection device and method. Background Art

[0002] As a new round of global scientific and technological revolution and industrial transformation deepens, strategic competition among major powers is further focusing on manufacturing, with intelligent manufacturing becoming a key focus. Industrial robots, as representatives of intelligent manufacturing equipment, are the focus of high-end manufacturing development. Their research and development, manufacturing, and application have become important indicators of a country's level of scientific and technological innovation. Positioning accuracy has become a key factor affecting robot performance. The position and orientation accuracy of the tool center point (TCP) at the end of an industrial robot directly affects work quality, and poor accuracy can even lead to the inability to complete the corresponding task. With the continuous development of high-end manufacturing, the positioning accuracy requirements of industrial robots are constantly increasing across various industries, especially in applications such as laser welding, laser cutting, and aerospace. This requires suitable positioning accuracy detection devices and measurement methods to measure and evaluate the position and orientation of the robot end.

[0003] Currently, the position of industrial robot end-points is primarily measured using external measurement equipment. Laser trackers, as high-precision, large-scale measuring instruments in industrial measurement systems, are one of the primary external measurement devices for industrial robots. This measurement device uses a target ball mounted on the end-point of the industrial robot and measures its spatial position using a laser tracker. The measured end-point position of the industrial robot must cover the robot's workspace as closely as possible. However, the target ball's laser reception range is limited to ±30°, making it impossible to measure any position of the industrial robot. While artificially modifying the target ball's posture can improve this situation to some extent, this also introduces significant measurement uncertainty. Furthermore, this equipment is currently relatively expensive. Therefore, there is an urgent need to invent and design a new, inexpensive, and simple end-point measurement device and method that can measure the position and posture of industrial robot end-points with high degrees of freedom and high measurement accuracy. Summary of the Invention

[0004] The purpose of the present invention is to provide an industrial robot positioning accuracy detection device and method, which can achieve high-degree-of-freedom and high-precision position and posture measurement of the industrial robot end.

[0005] To achieve the above object, the technical solution provided by the present invention is:

[0006] An industrial robot positioning accuracy detection device includes a posture measurement mechanism, a positioning device and a dual-feature mechanism;

[0007] The posture measurement mechanism includes a sensor bracket and three laser sensors: an X-axis laser ranging sensor, a Y-axis laser ranging sensor, and a Z-axis laser ranging sensor; the three laser sensors are mounted on the sensor bracket in a mutually perpendicular state; the rays emitted by the X-axis laser ranging sensor, the Y-axis laser ranging sensor, and the Z-axis laser ranging sensor intersect at a point, which is the origin of the posture measurement mechanism;

[0008] The positioning device includes a mounting frame, a vertical plate, a straight rod, a magnetic ring encoder, and a connecting rod mechanism. The vertical plate is mounted on the mounting frame and can slide up and down along the mounting frame. The vertical plate is perpendicular to the ground, and the straight rod is perpendicular to the plane where the vertical plate is located. One end of the straight rod is fixedly connected to the vertical plate. The magnetic ring encoder surrounds the straight rod and can slide along the length of the straight rod. A first grating scale is mounted on the vertical plate, and a second grating scale is mounted on the magnetic ring encoder. The magnetic ring encoder is connected to the sensor bracket via a connecting rod mechanism.

[0009] The dual-feature mechanism includes a Y-shaped connection mechanism, a spherical feature and a cubic feature; the Y-shaped connection mechanism has two branch rods and a bottom rod, the spherical feature and the cubic feature are respectively connected to the ends of the two branch rods of the Y-shaped connection mechanism, and the end of the bottom rod of the Y-shaped connection mechanism is a fixed end connected to the end of the industrial robot; the center point of the spherical feature and the center point of the cubic feature are symmetrical along the central axis of the bottom rod of the Y-shaped connection mechanism.

[0010] To optimize the above technical solutions, specific measures taken also include:

[0011] Furthermore, the mounting frame is a triangular bracket, and a slide groove perpendicular to the ground is provided on one side of the triangular bracket. The vertical plate is embedded in the slide groove and can slide up and down along the slide groove; the first grating scale is horizontally installed on the lower edge of the vertical plate.

[0012] Furthermore, the second grating scale is arranged parallel to the straight rod and is fixed to the magnetic ring encoder, and can slide on the straight rod together with the magnetic ring encoder.

[0013] Furthermore, the sensor bracket is composed of three identical square plates that are perpendicular to each other; the origin of the posture measurement mechanism is equidistant from the laser emission points of the X-axis laser ranging sensor, the Y-axis laser ranging sensor, and the Z-axis laser ranging sensor.

[0014] The present invention also protects a method for using the above-mentioned industrial robot positioning accuracy detection device, comprising the following steps:

[0015] Step (1): Install a dual-feature mechanism, a posture measurement mechanism, and a positioning device at the end of the industrial robot;

[0016] Step (2): Establish the system coordinate system: establish the world coordinate system, the industrial robot end coordinate system, the dual-feature mechanism coordinate system, the positioning device coordinate system and the posture measurement mechanism coordinate system;

[0017] Step (3): Setting the measurement point: by adjusting the posture measurement mechanism and the positioning device, the origin of the posture measurement mechanism is adjusted to an initial point, the initial point is recorded as the measurement point c1, and the position of the measurement point c1 in the world coordinate system is calculated;

[0018] Step (4): Calculation of the robot end position: by issuing instructions, the industrial robot drives the dual-feature mechanism to move, so that the center point of the spherical feature reaches the measurement point c1; according to the three points formed on the surface of the spherical feature by the rays emitted by the three laser sensors of the posture measurement mechanism, the coordinates t1 of the center point of the spherical feature in the posture measurement mechanism coordinate system are calculated, and the posture measurement mechanism coordinate system is converted to the world coordinate system through the positioning device coordinate system, and the coordinates t1 of the posture measurement mechanism is obtained. W The coordinates of the center of the sphere in the coordinate system t W1 , as the robot end position value;

[0019] Step (5): Calculation of the robot terminal posture: By issuing instructions, the industrial robot drives the dual-feature mechanism to rotate 180°, so that the center point of the cube feature reaches the coordinate t1 in the pose measurement mechanism coordinate system. According to the three points formed on the cube feature surface by the rays emitted by the three laser sensors of the pose measurement mechanism, the normal vectors of the cube surface planes where the three points are located are calculated, and the coordinate system of the pose measurement mechanism is converted to the world coordinate system via the positioning device coordinate system. The normal vector of one of the planes obtained by calculation is used as the robot terminal posture value;

[0020] Step (6): After completing the measurement and calculation of the robot end position value and the robot end posture value through steps (4) and (5), the industrial robot is made to move for a round, and the center point of the sphere feature and the center point of the cube feature are again made to reach the test point c1 in sequence, and the robot end position value and the robot end posture value are calculated again; repeat several times; and calculate the deviation value of the robot end position value and the deviation value of the robot end posture value.

[0021] The world coordinate system is established based on the industrial robot base coordinates. W The end coordinate system of the industrial robot is established with the center point of the connection between the bottom rod of the Y-shaped connection mechanism and the end of the industrial robot as the origin. E}, industrial robot end coordinate system {O E The Z axis of the robot is perpendicular to the flange plane of the robot end; establish the industrial robot end coordinate system {O EThe industrial robot needs to be calibrated before it can be used; the dual-feature mechanism coordinate system includes a spherical feature coordinate system established with the center point of the spherical feature as the origin {O T1} and the cube feature coordinate system {O T2}, where the industrial robot end coordinate system {O E The directions of the three axes establish the spherical feature coordinate system {O T1}, cube feature coordinate system {O T2 The Z axis of the cube is in the same direction as the center axis of the branch rod where the cube feature is located and is downward.

[0022] The positioning device coordinate system includes the mounting frame coordinate system {O0} established with a point on the bottom surface of the mounting frame as the origin, the straight rod coordinate system {O1} established with the intersection point of the central axis of the straight rod and the vertical plate plane as the origin, and the connecting rod mechanism coordinate system {O2} established with the intersection point of the central axis of the connecting rod mechanism and the central axis of the straight rod as the origin; the posture measurement mechanism coordinate system is the posture measurement mechanism coordinate system {O} established with the posture measurement mechanism as the origin and the rays emitted by the X-axis laser ranging sensor, the Y-axis laser ranging sensor and the Z-axis laser ranging sensor as the direction.

[0023] The position of the measuring point c1 in the world coordinate system is calculated in step (3), which is the data of the magnetic ring encoder, the first grating scale and the second grating scale, through the straight rod coordinate system {O1}, the connecting rod mechanism coordinate system {O2} and the mounting frame coordinate system {O0} and the world coordinate system {O W} is obtained by conversion.

[0024] In step (4), the industrial robot drives the dual-feature mechanism to move so that the center point of the spherical feature reaches the measurement point c1, which is controlled by the spherical feature coordinate system {O T1}、Industrial robot terminal coordinate system {O E} and the world coordinate system {O W} after conversion, the instruction is issued through the teaching pendant; in step (5), the industrial robot drives the dual-feature mechanism to rotate 180° so that the center point of the cube feature reaches the coordinate t1 in the coordinate system of the posture measurement mechanism. The control is carried out by the cube feature coordinate system {O T2}、Industrial robot terminal coordinate system {O E} and the world coordinate system {O W}, and then issue the instruction through the teaching pendant.

[0025] As a preferred solution, the position of the measuring point c1 can be changed by adjusting the positioning device to determine the deviation values ​​of the calculated robot end position value and the robot end posture value at different initial points.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The industrial robot positioning accuracy detection device of the present invention can achieve high-precision measurement of both the end position and posture of the industrial robot;

[0028] The industrial robot positioning accuracy detection device of the present invention has a simple structure, low measurement cost and high cost performance;

[0029] The industrial robot positioning accuracy detection device of the present invention is a non-contact measurement device, which can reduce the possibility of collision between the robot end and the measuring mechanism caused by the robot positioning error, making the system operation safer and more efficient.

[0030] The measurement process of the present invention is simple in steps, easy to operate, has low requirements on the working environment, has a wide range of applications, and can play a greater role in the measurement process of robot positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the industrial robot positioning accuracy detection device of the present invention;

[0032] Figure 2 It is a schematic diagram of establishing the system coordinate system of the present invention;

[0033] Figure 3 Schematic diagram of the structure of the posture measurement mechanism of the present invention and its coordinate system;

[0034] Figure 4 It is a schematic diagram of the structure of the dual-feature mechanism of the present invention and its coordinate system;

[0035] Figure 5 It is a schematic diagram of the double-feature mechanism in the structure of the industrial robot positioning accuracy detection device of the present invention after rotation. DETAILED DESCRIPTION

[0036] The above contents of the present invention are further described in detail below in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments. All technologies implemented based on the above contents of the present invention fall within the scope of the present invention.

[0037] The present invention provides an industrial robot positioning accuracy detection device, such as Figure 1 、 Figure 5 As shown, it includes a posture measurement mechanism 1, a positioning device and a dual-feature mechanism 8;

[0038] like Figure 3As shown, the posture measurement mechanism 1 includes a sensor bracket 13 and three laser sensors: an X-axis laser ranging sensor 12, a Y-axis laser ranging sensor 11, and a Z-axis laser ranging sensor 10; the three laser sensors are mounted on the sensor bracket 13 in a mutually perpendicular state; the rays emitted by the X-axis laser ranging sensor 12, the Y-axis laser ranging sensor 11, and the Z-axis laser ranging sensor 10 intersect at a point, which is the origin of the posture measurement mechanism 1;

[0039] The positioning device includes a mounting frame 7, a vertical plate 6, a straight rod, a magnetic ring encoder 2 and a connecting rod mechanism 4. The vertical plate 6 is mounted on the mounting frame 7 and can slide up and down along the mounting frame 7. The vertical plate 6 is perpendicular to the ground, and the straight rod is perpendicular to the plane where the vertical plate 6 is located. One end of the straight rod is fixedly connected to the vertical plate 6; the magnetic ring encoder 2 is wrapped around the straight rod and can slide along the length of the straight rod; a first grating scale 5 is mounted on the vertical plate 6, and a second grating scale 3 is mounted on the magnetic ring encoder 2; the magnetic ring encoder 2 is connected to the sensor bracket 13 via the connecting rod mechanism 4;

[0040] like Figure 4 As shown, the dual-feature mechanism 8 includes a Y-shaped connection mechanism, a spherical feature 14 and a cubic feature 15; the Y-shaped connection mechanism has two branch rods and a bottom rod, the spherical feature 14 and the cubic feature 15 are respectively connected to the ends of the two branch rods of the Y-shaped connection mechanism, and the end of the bottom rod of the Y-shaped connection mechanism is a fixed end connected to the end of the industrial robot; the center point of the spherical feature 14 and the center point of the cubic feature 15 are symmetrical along the central axis of the bottom rod of the Y-shaped connection mechanism.

[0041] To optimize the above technical solutions, specific measures taken also include:

[0042] Furthermore, the mounting frame 7 is a triangular bracket, and a slide groove perpendicular to the ground is provided on one side of the triangular bracket. The vertical plate 6 is embedded in the slide groove and can slide up and down along the slide groove; the first grating scale 5 is horizontally installed on the lower edge of the vertical plate 6.

[0043] Furthermore, the second grating scale 3 is arranged parallel to the straight rod and is fixed to the magnetic ring encoder 2 , and can slide on the straight rod together with the magnetic ring encoder 2 .

[0044] Furthermore, the sensor bracket 13 is composed of three identical square plates that are perpendicular to each other; the origin of the posture measurement mechanism 1 is equidistant from the laser emission points of the X-axis laser ranging sensor 12, the Y-axis laser ranging sensor 11 and the Z-axis laser ranging sensor 10.

[0045] The present invention also protects a method for using the above-mentioned industrial robot positioning accuracy detection device, comprising the following steps:

[0046] Step (1): Install a dual-feature mechanism, a posture measurement mechanism, and a positioning device at the end of the industrial robot;

[0047] Step (2): Establish the system coordinate system: establish the world coordinate system, the industrial robot end coordinate system, the dual-feature mechanism coordinate system, the positioning device coordinate system and the posture measurement mechanism coordinate system;

[0048] Step (3): Setting the measurement point: by adjusting the posture measurement mechanism and the positioning device, the origin of the posture measurement mechanism is adjusted to an initial point, the initial point is recorded as the measurement point c1, and the position of the measurement point c1 in the world coordinate system is calculated;

[0049] Step (4): Calculation of robot end position: Figure 1 As shown, the robot is controlled by the teaching pendant, so that the industrial robot drives the dual-feature mechanism to move, so that the center point of the spherical feature 14 reaches the measurement point c1; according to the three points formed on the surface of the spherical feature 14 by the rays emitted by the three laser sensors of the posture measurement mechanism, the coordinates t1 of the center point of the spherical feature in the posture measurement mechanism coordinate system are calculated, and the posture measurement mechanism coordinate system is converted to the world coordinate system through the positioning device coordinate system, and the coordinates t1 of the posture measurement mechanism is obtained. W The coordinates of the center of the sphere in the coordinate system t W1 , as the robot end position value;

[0050] Step (5): Calculation of robot terminal posture: Figure 5 As shown, the robot is controlled by the teach pendant, so that the industrial robot drives the dual-feature mechanism to rotate 180 degrees, so that the center point of the cube feature 15 reaches the coordinate t1 in the pose measurement mechanism coordinate system. Based on the three points formed on the surface of the cube feature 15 by the rays emitted by the three laser sensors of the pose measurement mechanism, the normal vectors of the cube surface planes where the three points are located are calculated, and then converted from the pose measurement mechanism coordinate system to the world coordinate system via the positioning device coordinate system. The normal vector of one of the planes obtained by calculation is used as the robot end posture value;

[0051] Step (6): After completing the measurement and calculation of the robot end position value and the robot end posture value through steps (4) and (5), the industrial robot is made to move for a round, and the center point of the sphere feature 14 and the center point of the cube feature 15 are again made to reach the test point c1 in sequence, and the robot end position value and the robot end posture value are calculated again; repeat several times; and calculate the deviation value of the robot end position value and the deviation value of the robot end posture value.

[0052] like Figure 2 As shown, the world coordinate system is the world coordinate system established based on the industrial robot base coordinates {O WThe end coordinate system of the industrial robot is established with the center point of the connection between the bottom rod of the Y-shaped connection mechanism and the industrial robot as the origin. E}, industrial robot end coordinate system {O E The Z axis of the robot is perpendicular to the flange plane of the robot end; establish the industrial robot end coordinate system {O E The industrial robot needs to be calibrated before the dual-feature mechanism coordinate system includes a spherical feature coordinate system {O T1} and the cube feature coordinate system {O T2}, where the industrial robot end coordinate system {O E The directions of the three axes establish the spherical feature coordinate system {O T1}, cube feature coordinate system {O T2 The Z axis of the cube is in the same direction as the center axis of the branch rod where the cube feature 15 is located and is downward.

[0053] The positioning device coordinate system includes a mounting frame coordinate system {O0} established with a point on the bottom surface of the mounting frame 7 as the origin, a straight rod coordinate system {O1} established with the intersection point of the central axis of the straight rod and the vertical plate 6 as the origin, and a connecting rod mechanism coordinate system {O2} established with the intersection point of the central axis of the connecting rod mechanism and the central axis of the straight rod as the origin; the posture measurement mechanism coordinate system is a posture measurement mechanism coordinate system {O} established with the posture measurement mechanism 1 as the origin and the rays emitted by the X-axis laser ranging sensor 12, the Y-axis laser ranging sensor 11 and the Z-axis laser ranging sensor 10 as the direction.

[0054] The position of the measuring point c1 in the world coordinate system is calculated in step (3), which is the data of the magnetic ring encoder 2, the first grating scale 5 and the second grating scale 3, through the straight rod coordinate system {O1}, the connecting rod mechanism coordinate system {O2} and the mounting frame coordinate system {O0} and the world coordinate system {O W} is obtained by conversion.

[0055] In step (4), the industrial robot drives the dual-feature mechanism to move so that the center point of the spherical feature 14 reaches the measurement point c1, which is controlled by the spherical feature coordinate system {O T1}、Industrial robot terminal coordinate system {O E} and the world coordinate system {O W} after conversion, the instruction is issued through the teaching pendant; in step (5), the industrial robot drives the dual-feature mechanism to rotate 180° so that the center point of the cube feature 15 reaches the coordinate t1 in the coordinate system of the posture measurement mechanism. The control is carried out by the cube feature coordinate system {O T2}、Industrial robot terminal coordinate system {O E} and the world coordinate system {OW}, and then issue the instruction through the teaching pendant.

[0056] As a preferred solution, the position of the measuring point c1 can be changed by adjusting the positioning device to determine the deviation values ​​of the calculated robot end position value and the robot end posture value at different initial points.

[0057] The following is a specific measurement method embodiment combined with the calculation process:

[0058] Step 1: Install the positioning accuracy measurement device:

[0059] Install the dual-feature mechanism 8 on the end of the industrial robot 9 and install the various parts of the positioning device. After the installation is completed, test the motion space range of the industrial robot 9, calculate the approximate position where the positioning device needs to be installed, and after ensuring that it is within the working range of the industrial robot 9, fix the mounting frame 7 of the positioning device.

[0060] Step 2: Establish the system coordinate system:

[0061] The world coordinate system is established with the 9-base coordinates of the industrial robot as the origin. W}, calibrate the industrial robot 9 and establish the industrial robot terminal coordinate system {O E}; Establish the coordinate system of the positioning device, establish the mounting frame coordinate system {O0} with a certain point on the bottom surface of the tripod bracket 7 as the origin, establish the straight rod coordinate system {O1} with the intersection of the central axis of the straight rod and the plane of the vertical plate 6 as the origin, and establish the connecting rod mechanism coordinate system {O2} with the intersection of the central axis of the connecting rod and the central axis of the straight rod as the origin.

[0062] The intersection of the laser beams of the Z-axis laser ranging sensor 10, the Y-axis laser ranging sensor 11, and the X-axis laser ranging sensor 12 is taken as the origin, and the direction of the laser beam is taken as the positive direction to establish the coordinate system {O}. In the {O} coordinate system, the laser emission point a of the X-axis laser ranging sensor 12 is x (m x , 0, 0), Y-axis laser distance sensor 11 laser emission point a y (0, m y ,0), Z-axis laser ranging sensor 10 laser emission point a z (0, 0, m z ), the intersection point of the three-axis laser rays is O(0, 0, 0).

[0063] The spherical feature coordinate system {0 is established with the center point of the spherical feature 14 of the double feature mechanism 8 as the origin T1}, establish the cube feature coordinate system with the center point of the double feature mechanism 8 cube feature 15 as the origin {O T2}, where the industrial robot end coordinate system {OE The directions of the three axes establish the spherical feature coordinate system {O T1}, cube feature coordinate system {O T2 The Z axis of the cube is in the same direction as the center axis of the branch rod where the cube feature 15 is located and is downward.

[0064] Step 3: Set the measurement point.

[0065] Manually adjust the position of the posture measurement mechanism 1, translate along the straight rod direction and rotate around the straight rod through the connecting rod mechanism 4, and raise and lower the vertical plate 6, so that the origin of the posture measurement mechanism coordinate system {O} reaches an initial position in space, which is recorded as measurement point c1. Record the data of the magnetic ring encoder 2, the second grating scale 3, and the first grating scale 5. According to the structural characteristics of the device, the position in the world coordinate system {O} can be calculated. W}Measuring point c under W1 Position, the homogeneous transformation matrix is is the transformation matrix from coordinate system {O} to coordinate system {W}, is the transformation matrix from coordinate system {O} to coordinate system {O2}, is the transformation matrix from coordinate system {O2} to coordinate system {O1}, is the transformation matrix from coordinate system {O1} to coordinate system {O0}, is the transformation matrix from coordinate system {O0} to coordinate system {W}.

[0066] Step 4: Data measurement.

[0067] It is known that in the world coordinate system {O W}, the industrial robot 9 is controlled by the teaching pendant to move so that the center of the spherical feature 14 of the dual-feature mechanism 8 installed at the end of the industrial robot 9 reaches the measuring point c1. Here, the three laser sensors perform the first data acquisition. The data collected by the three laser sensors on the XYZ axes of the posture measurement mechanism 1 are x c 、y c 、z c .

[0068] Step 5: Calculate the robot end position.

[0069] In the {O} coordinate system, the c1 coordinate is (0, 0, 0), and the theoretical function expression of the surface of the spherical feature 14 is expressed as: sph 2 +y sph 2 +z sph 2 =R 2The radius of the spherical feature 14 is known to be R, and the center of the sphere theoretically coincides with c1. In the {O} coordinate system, three points (m x +x c ,0,0),(0,m y +y c ,0),(0,0,m z +z c ), and the radius of the sphere is R, let the actual coordinate of the center of the sphere be t1(t x , t y , t z ), list the function expression of sphere feature 14: (xt x ) 2 +(yt y ) 2 +(zt z ) 2 =R 2 , put the three known points on the sphere into the spherical equation and calculate the coordinate t1 of the center of the sphere in the {O} coordinate system. W}, the homogeneous transformation matrix is Find the value in {O W The coordinates of the center of the sphere in the coordinate system t W1 , and the calculated t W1 The ball center position data is used as the robot end value.

[0070] Step 6: Calculate the robot's terminal posture.

[0071] The industrial robot 9 is controlled to rotate the dual-feature mechanism 8 at the end 180 degrees, so that the cube feature 15 enters the measurement range of the posture measurement mechanism 1. According to the structural characteristics of the designed dual-feature mechanism 8 (the center point of the spherical feature and the center point of the cube feature are symmetrical along the central axis of the bottom rod of the Y-shaped connecting mechanism), the center point of the cube feature 15 coincides with the center point of the spherical feature 14 at coordinate t1. The laser ranging sensor can obtain the coordinates of the points on the three outer surfaces of the cube feature 15 in the {O} coordinate system, which are P and P respectively. O1 (x O ,0,0),P O2 (0,y O ,0)P O3 (0, 0, z O ), through homogeneous transformation Get the three points P corresponding to the coordinate system {W} W1 (x1, y1, z1), P W2 (x2, y2, z2), P W3(x3, y3, z3), according to the structural characteristics of the designed dual-feature mechanism 8 and the conversion between coordinate systems, the theoretical values ​​of the spatial plane expressions of the three outer surfaces are known.

[0072] At this time, in the coordinate system {O T2}, let P T2,1 The normal vector of the plane is P T2,2 The normal vector of the plane is P T2,3 The normal vector of the plane is Then P T2,1 With P T2,2 The relationship is expressed as P T2,1 With P T2,3 The relationship is expressed as

[0073] In the world coordinate system {O W}, the center point t of the regular cube feature 15 W2 and the center point t of the sphere feature 14 W1 coincident, and assuming that the side length of the known cube feature 15 is 2d, the transformation matrix For the coordinate system {O T2} to coordinate system {O W}'s transformation matrix, For the coordinate system {O T2} to coordinate system {O E}'s transformation matrix, For the coordinate system {O E} to coordinate system {O W}. Let the normal vector of the plane where P1 is located be Parallel to this plane and passing through the center point t W2 The plane is x P1 +Ay P1 +Bz P1 +C1=0, then the plane is represented by Π1:x P1 '+Ay P1 '+Bz P1 '+(C1+d)=0. After transformation, we get That is, the normal vector of the plane where P2 is located is Where a, b, c are represented by A and B, where a=α1A+β1B+γ1, b=α2A+β2B+γ2, c=α3A+β3B+γ3(α i , β i , γ i (i=1,2,3) are known quantities calculated by transformation), parallel to this plane and passing through the center point tW2 The plane is ax P2 +by P2 +cz P2 +C2=0, then the plane is represented by Π2:ax P2 '+by P2 '+cz P2 '+(C2+d)=0. After transformation, we get That is, the normal vector of the plane where P3 is located is Among them, m, n, and p are represented by A and B. is a known quantity calculated by transformation), which is parallel to this plane and passes through the center point t W2 The plane is mx P3 +ny P3 +pz P3 +C3=0, the plane is expressed as Π3:mx P3 '+ny P3 '+pz P3 '+(C3+d)=0. a, b, c, m, n, p are expanded with the expression of A and B, and t W2 The value of t is brought into the three passing through the center point W2 The plane of P1, P2, and P3 is substituted into Π1, Π2, and Π3 respectively, and the matrix equation is listed as follows:

[0074]

[0075] The above equation can be expressed as MX+D=0, where

[0076] Transform the above equation to: MX = -D, and use the least squares method to find X = (M T M) -1 M T (-D), that is, the unknown quantities A, B, C1, C2, and C3. From this, we get the normal vector The value of the normal vector direction data calculated this time is used as the robot end posture value (calculated Other normal vectors It can also be known, but only one needs to be used as the robot end posture value).

[0077] Step 7: After completing a measurement, before reaching the measurement point next time, make the industrial robot 9 perform a periodic motion with a specific posture, speed and trajectory (the periodic motion posture, speed and trajectory can be set to be the same before each return to the test point c1), then repeat the teaching content of the previous measurement, let the industrial robot 9 move the center point of the spherical feature 14 of the terminal double feature mechanism 8 to the test point c1 again, and record the data measured by the laser sensor at this time. Perform step 5 to obtain the sphere center t W1,i The coordinates are compared with the values ​​calculated in step 5 to obtain the deviation value Δx i , Δy i , Δz i ; Perform step 6 to find the normal vector Compare with the value calculated in step 6 to obtain the deviation value Δθ of each direction angle x,i , Δθ y,i , Δθ z,i Repeat the above operation to obtain the positioning accuracy test data for the i-th time, and calculate the position error and attitude error for the i-th time, where i = 1, 2, 3, ...

[0078] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modification, equivalent replacement and improvement made by any technician familiar with the profession to the above embodiment without departing from the scope of the technical solution of the present invention and based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An industrial robot positioning accuracy detection device, characterized by: It includes a posture measurement mechanism (1), a positioning device and a dual-feature mechanism (8); The posture measurement mechanism (1) includes a sensor bracket (13) and three laser sensors: an X-axis laser ranging sensor (12), a Y-axis laser ranging sensor (11), and a Z-axis laser ranging sensor (10); the three laser sensors are mounted on the sensor bracket (13) in a mutually perpendicular state; the rays emitted by the X-axis laser ranging sensor (12), the Y-axis laser ranging sensor (11), and the Z-axis laser ranging sensor (10) intersect at a point, which is the origin of the posture measurement mechanism (1); The positioning device comprises a mounting frame (7), a vertical plate (6), a straight rod, a magnetic ring encoder (2) and a connecting rod mechanism (4), wherein the vertical plate (6) is mounted on the mounting frame (7) and can slide up and down along the mounting frame (7), the vertical plate (6) is perpendicular to the ground, the straight rod is perpendicular to the plane where the vertical plate (6) is located, and one end of the straight rod is fixedly connected to the vertical plate (6); the magnetic ring encoder (2) is wrapped around the straight rod and can slide along the length direction of the straight rod; a first grating scale (5) is mounted on the vertical plate (6), and a second grating scale (3) is mounted on the magnetic ring encoder (2); the magnetic ring encoder (2) is connected to the sensor bracket (13) through the connecting rod mechanism (4); The dual-feature mechanism (8) includes a Y-shaped connection mechanism, a spherical feature (14) and a cubic feature (15); the Y-shaped connection mechanism has two branch rods and a bottom rod, the spherical feature (14) and the cubic feature (15) are respectively connected to the ends of the two branch rods of the Y-shaped connection mechanism, and the end of the bottom rod of the Y-shaped connection mechanism is a fixed end connected to the end of the industrial robot (9); the center point of the spherical feature (14) and the center point of the cubic feature (15) are symmetrical along the central axis of the bottom rod of the Y-shaped connection mechanism.

2. The industrial robot positioning accuracy detection device according to claim 1, characterized in that: The mounting frame (7) is a triangular bracket, and a slide groove perpendicular to the ground is provided on one side of the triangular bracket. The vertical plate (6) is embedded in the slide groove and can slide up and down along the slide groove; the first grating ruler (5) is horizontally installed on the lower edge of the vertical plate (6).

3. The industrial robot positioning accuracy detection device according to claim 1, characterized in that: The second grating ruler (3) is arranged parallel to the straight rod and is fixed to the magnetic ring encoder (2), and can slide on the straight rod together with the magnetic ring encoder (2).

4. The industrial robot positioning accuracy detection device according to claim 1, characterized in that: The sensor bracket (13) is composed of three identical square plates that are perpendicular to each other; the origin of the posture measurement mechanism (1) is equidistant from the laser emission points of the X-axis laser ranging sensor (12), the Y-axis laser ranging sensor (11), and the Z-axis laser ranging sensor (10).

5. A method for using the industrial robot positioning accuracy detection device according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: Install the dual-feature mechanism, posture measurement mechanism and positioning device at the end of the industrial robot; Step 2: Establish the system coordinate system: establish the world coordinate system, the industrial robot end coordinate system, the dual-feature mechanism coordinate system, the positioning device coordinate system and the posture measurement mechanism coordinate system; Step 3: Set the measurement point: Adjust the posture measurement mechanism and the positioning device so that the origin of the posture measurement mechanism reaches an initial point. This initial point is recorded as the measurement point c1, and the position of the measurement point c1 in the world coordinate system is calculated. Step 4: Calculation of the robot end position: Control the robot through the teaching pendant, so that the industrial robot drives the dual-feature mechanism to move, so that the center point of the spherical feature reaches the measurement point c1; Based on the three points formed on the surface of the spherical feature by the rays emitted by the three laser sensors of the posture measurement mechanism, the coordinates t1 of the center point of the spherical feature in the posture measurement mechanism coordinate system are calculated, and the coordinate system of the posture measurement mechanism is converted to the world coordinate system through the positioning device coordinate system to obtain the coordinates t of the center point of the spherical feature in the world coordinate system. W1 , as the robot end position value; Step 5: Calculate the robot's end-point posture: Control the robot using the teach pendant, causing the industrial robot to drive the dual-feature mechanism to rotate 180° until the center point of the cube feature reaches coordinate t1 in the pose measurement mechanism's coordinate system. Based on the three points formed on the cube feature surface by the rays emitted by the pose measurement mechanism's three laser sensors, calculate the normal vectors of the cube's surface planes where these three points lie. This is then converted from the pose measurement mechanism's coordinate system to the world coordinate system via the positioning device's coordinate system. The calculated normal vector of one of the planes is used as the robot's end-point posture value. Step 6: After completing the measurement and calculation of the robot's end position value and the robot's end posture value through steps 4 and 5, make the industrial robot move once again, and make the center point of the sphere feature and the center point of the cube feature reach the measurement point c1 in turn, and calculate the robot's end position value and the robot's end posture value again; repeat several times; calculate the deviation value of the robot's end position value and the deviation value of the robot's end posture value.

6. The method for using the industrial robot positioning accuracy detection device according to claim 5, characterized in that: The world coordinate system is established based on the industrial robot base coordinates. W The end coordinate system of the industrial robot is established with the center point of the connection between the bottom rod of the Y-shaped connection mechanism and the end of the industrial robot as the origin. E }, industrial robot end coordinate system {O E The Z axis of the robot is perpendicular to the flange plane of the robot end; establish the industrial robot end coordinate system {O E The industrial robot needs to be calibrated before it can be used; the dual-feature mechanism coordinate system includes a spherical feature coordinate system established with the center point of the spherical feature as the origin {O T1 } and the cube feature coordinate system {O T2 }, where the industrial robot end coordinate system {O E The directions of the three axes establish the spherical feature coordinate system {O T1 }, cube feature coordinate system {O T2 The Z axis of the cube is in the same direction as the center axis of the branch rod where the cube feature is located and is downward.

7. The method for using the industrial robot positioning accuracy detection device according to claim 6, characterized in that: The positioning device coordinate system includes a mounting frame coordinate system {O0} established with a point on the bottom surface of the mounting frame (7) as the origin, a straight rod coordinate system {O1} established with the intersection point of the central axis of the straight rod and the plane of the vertical plate (6) as the origin, and a connecting rod mechanism coordinate system {O2} established with the intersection point of the central axis of the connecting rod mechanism and the central axis of the straight rod as the origin; the posture measurement mechanism coordinate system is a posture measurement mechanism coordinate system {O} established with the intersection point of rays emitted by the X-axis laser ranging sensor (12), the Y-axis laser ranging sensor (11) and the Z-axis laser ranging sensor (10) as the origin and the rays emitted by the X-axis laser ranging sensor (12), the Y-axis laser ranging sensor (11) and the Z-axis laser ranging sensor (10) as the direction.

8. The method for using the industrial robot positioning accuracy detection device according to claim 7, characterized in that: In step 3, the position of the measuring point c1 in the world coordinate system is calculated by the data of the magnetic ring encoder (2), the first grating ruler (5) and the second grating ruler (3), through the straight rod coordinate system {O1}, the connecting rod mechanism coordinate system {O2} and the mounting frame coordinate system {O0} and the world coordinate system {O W } is obtained by conversion.

9. The method for using the industrial robot positioning accuracy detection device according to claim 6, characterized in that: In step 4, the industrial robot drives the dual-feature mechanism to move so that the center point of the spherical feature reaches the measurement point c1. The control is as follows: the spherical feature coordinate system in the dual-feature mechanism coordinate system {O T1 }、Industrial robot terminal coordinate system {O E } and the world coordinate system {O W }, the instruction is issued through the teaching pendant; in step 5, the industrial robot drives the dual-feature mechanism to rotate 180° so that the center point of the cube feature reaches the coordinate t1 in the coordinate system of the posture measurement mechanism. The control is carried out by the cube feature coordinate system {O T2 }、Industrial robot terminal coordinate system {O E } and the world coordinate system {O W }, and then issue the instruction through the teaching pendant.

10. The method for using the industrial robot positioning accuracy detection device according to claim 5, characterized in that: By adjusting the positioning device, the position of the measuring point c1 can be changed to measure the deviation of the robot end position value and the deviation of the robot end posture value at different initial points.

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