CN205466311U - Calibration system of robot based on terminal incomplete coordinate information - Google Patents

Abstract

The utility model relates to a calibration system of robot based on terminal incomplete coordinate information belongs to the robot and marks the field. The magnetism gauge stand passes through magnetic force to be installed on fixed platform, and the magnetism gauge stand links together through the connecting rod with cable sensor, and the end that cable sensor acted as go -between is installed on the universal joint, posts angular transducer on the universal joint, and angular transducer moves along with the universal joint, and the universal joint is installed in the robot, cable sensor, angular transducer pass through cable sensor cable, angular transducer cable and computer connecting communication respectively, and the robot passes through robot cable and computer connecting communication, through computer acquisition cable sensor's the length of acting as go -between, angular transducer's angle, the joint corner of robot. The utility model provides reliability and precision that high structural parameters resolved, the operating is simplified step has improved calibration efficiency.

Description

Robot calibration system based on terminal incomplete coordinate information

Technical Field

The utility model relates to a calibration system of robot based on terminal incomplete coordinate information belongs to the robot and marks the field.

Background

With the wide application of robots in various industries, the industries have strict requirements on the repeated positioning precision and the absolute positioning precision of the industrial robot in space during movement, and because the robot is a multi-degree-of-freedom device, the structural form has the defect of accumulated and amplified errors, and the structural parameter errors of all levels of joints can be amplified step by step, so that the precision of the robot is reduced.

Calibration is an effective method for eliminating errors of structural parameters of a robot, and currently, a commonly used robot calibration method generally uses a laser tracker, a laser interferometer, a three-coordinate measuring machine and other precision measuring instruments.

The common characteristics of the methods are that the coordinate value of the tail end of the robot is measured, the needed calibration equipment is high in cost, the operation steps are complex, the requirement on the technical level of operators is high, data acquisition is time-consuming and labor-consuming, and automation is difficult to realize.

Disclosure of Invention

The utility model provides a calibration system of robot based on terminal incomplete coordinate information to solve current equipment with high costs, the operating procedure is loaded down with trivial details, positioning accuracy low grade problem.

The technical scheme of the utility model is that: a robot calibration system based on terminal incomplete coordinate information comprises a fixed platform 1, a magnetic gauge stand 2, a connecting rod 3, a stay wire sensor 4, a tilt angle sensor 5, a universal joint 6, a robot 7, a stay wire sensor cable 8, a robot cable 9, a tilt angle sensor cable 10 and a computer 11;

The magnetic gauge stand 2 is installed on the fixed platform 1 through magnetic force, the magnetic gauge stand 2 is connected with the stay wire sensor 4 through the connecting rod 3, the tail end of a stay wire of the stay wire sensor 4 is installed on a universal joint 6, an inclination angle sensor 5 is attached to the universal joint 6, the inclination angle sensor 5 moves along with the universal joint 6, and the universal joint 6 is installed on a robot 7; the stay wire sensor 4 and the tilt angle sensor 5 are respectively connected and communicated with a computer 11 through a stay wire sensor cable 8 and a tilt angle sensor cable 10, and the robot 7 is connected and communicated with the computer 11 through a robot cable 9; the computer 11 is used for acquiring the length of the stay wire sensor 4, the angle of the inclination angle sensor 5 and the joint rotation angle of the robot 7.

The utility model discloses a theory of operation is: connecting a stay wire sensor 4, an inclination angle sensor 5, a universal joint 6 and a robot 7, acquiring the length of the stay wire sensor 4, the angle of the inclination angle sensor 5 and the joint rotation angle of the robot 7 through a computer 11, and changing the pose of the robot 7 according to a joint transformation sequence to acquire sufficient data; firstly, determining the direction vector of the stay wire according to the collected angle, secondly, calculating the included angle of the stay wire for any two times according to the direction vector, and finally, calculating the distance between two points of the tail end of the robot 7 in the space according to the calculated included angle and the stay wire length collected for any two times. And obtaining an equation with the structure parameters of the robot 7 as unknown quantity according to the distance between two points in space at the tail end of the robot 7 and a kinematic equation of the robot 7, and solving the equation to realize the calibration of the robot.

The method comprises the following specific steps:

step1, attaching the tilt angle sensor 5 to the universal joint 6, and mounting the universal joint 6 at the tail end of the robot 7;

step2, installing the pull sensor 4 on the magnetic meter base 2 through the connecting rod 3, fixing the magnetic meter base 2, and connecting the pull of the pull sensor 4 with the tail end of the universal joint 6;

step3, powering on, opening the tilt sensor 5, the pull sensor 4 and the robot 7, and moving the robot 7 to an initial pose and meeting the condition that an initialized counting variable v is 0;

step4, judging whether the data acquisition operation is finished or not;

if the data acquisition is finished, turning to Step7, and if the data acquisition is not finished, turning to Step 4;

step5, increment of the counting variable by 1: v ═ v + 1;

step6, acquiring the length of a stay wire of the stay wire sensor 4, the angle data of the inclination angle sensor 5 and the joint rotation angle data of the robot 7 through the computer 11;

step7, changing the pose of the robot 7, wherein the changing principle is as follows: sequentially transforming the rotation angle of each joint according to the sequence of the joints (for example, sequentially moving according to the principle that the joints are from small to large, the joints are transformed from 0 degrees to 20 degrees, then transformed from 20 degrees to 40 degrees, and so on, the angle of each transformed joint is increased by 20 degrees and is increased to 340 degrees all the time, namely the pose transformation of the joint is completed, and the other joints can also move according to the method, so that each joint of the robot 7 can fully move, and a user can also increase or reduce the number of times of pose transformation so as to obtain more data); wherein the times of all joint transformation are t, and the Step4 is returned to for judgment every time of transformation;

Step8, after data acquisition is finished, making t equal to v;

step9, calculating the distance between two continuous points i and j in the end space of the robot 7:

after the data acquisition is finished, the distance l between two continuous points i and j in the tail end space of the robot 7 can be calculated by using the acquired data_i,j(ii) a Because the stay wire of the stay wire sensor 4 is always vertical to the plane where the tilt angle sensor 5 is located, and the tilt angle sensor 5 and the stay wire move together along with the universal joint 6, the angles acquired by the tilt angle sensor 5 are the included angle alpha between the stay wire and the x axis of the horizontal plane and the included angle beta between the stay wire and the y axis: firstly, calculating a direction vector of a stay wire through the acquired angle, secondly, calculating an included angle between the stay wire at the position i and the stay wire at the position j according to the direction vector of the stay wire, and finally, calculating the distance between the two points i at the tail end of the robot 7 and j at the tail end of the robot 7 according to the included angle between the stay wire at the position i and the stay wire at the position j and the length of the stay wire at the position i and the stay wire at the position j;

calculation of the direction vector:

direction vector of the pull line at position i:

using the direction cosine cos alpha_i ²+cosβ_i ²+cosγ_i ²Calculate the angle γ as 1_iThus, the direction vector m of the wire at the i position is determined, m ═ cos α_i,cosβ_i,cosγ_i)；

The direction vector n of the pull line at position j is: n ═ cos α_j,cosβ_j,cosγ_j)；

The angle between the stay at the i position and the stay at the j position Comprises the following steps:

calculating the distance between the two points i and j at the tail end of the robot 7:

according toTheorem of cosinesFinding the distance l between two points i and j in space at the end_i,j(ii) a In the formula I_i、l_jThe length of the stay wire sensor 4 is shown when the tail end positions of the robot 7 are i and j respectively; alpha is alpha_i、β_i、γ_iRespectively showing the included angle between the stay wire and the x axis, the included angle between the stay wire and the y axis and the included angle between the stay wire and the z axis when the tail end position of the robot 7 is i; alpha is alpha_j、β_j、γ_jRespectively showing the included angle between the stay wire and the x axis, the included angle between the stay wire and the y axis and the included angle between the stay wire and the z axis when the tail end position of the robot 7 is j;

step10, solving the structural parameters of the robot 7 to be calibrated:

the distance l is calculated by using the collected joint rotation angle data of the robot 7_i,jAnd the kinematic equation for robot 7 lists t equations, each of the form:

$l_{i,j}=\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}$

wherein, $\begin{array}{c}{x}_i=f_x({\mathrm{\θ}}_{i,1},{\mathrm{\θ}}_{i,2},...,{\mathrm{\θ}}_{i,w},q)\\ y_i=f_y({\mathrm{\θ}}_{i,1},{\mathrm{\θ}}_{i,2},...,{\mathrm{\θ}}_{i,w},q)\\ z_i=f_z({\mathrm{\θ}}_{i,1},{\mathrm{\θ}}_{i,2},...,{\mathrm{\θ}}_{i,w},q)\end{array}$ coordinate value theta indicating that the end position of the robot 7 is at i_i,1,θ_i,2,…,θ_i,wRepresenting w joint rotation angle values when the tail end position of the robot 7 is located at i, and q is a structural parameter vector of the robot 7 to be identified;

$\begin{array}{c}{x}_j=f_x({\mathrm{\θ}}_{j,1},{\mathrm{\θ}}_{j,2},...,{\mathrm{\θ}}_{j,w},q)\\ y_j=f_y({\mathrm{\θ}}_{j,1},{\mathrm{\θ}}_{j,2},...,{\mathrm{\θ}}_{j,w},q)\\ z_j=f_z({\mathrm{\θ}}_{j,1},{\mathrm{\θ}}_{j,2},...,{\mathrm{\θ}}_{j,w},q)\end{array}$ coordinate value theta indicating that the end position of the robot 7 is at j_j,1,θ_j,2,…,θ_j,wW joint rotation angle values representing when the robot 7 end position is at j;

step10, solving an equation system consisting of t equations:

$\begin{array}{c}{l}_{1,2}=\sqrt{{(x_1-x_2)}^2+{(y_1-y_2)}^2+{(z_1-z_2)}^2}\\ l_{2,3}=\sqrt{{(x_2-x_3)}^2+{(y_2-y_3)}^2+{(z_2-z_3)}^2}\\ ...\\ l_{t-1,t}=\sqrt{{(x_{t-1}-x_t)}^2+{(y_{t-1}-y_t)}^2+{(z_{t-1}-z_t)}^2}\end{array}$

In the above equation set, only the structural parameter vector q of the robot 7 to be identified is uncertain, and the precise value of the structural parameter vector q can be obtained by solving by using a nonlinear least square method;

and Step11, substituting the structural parameter vector q into the kinematic equation of the robot 7, verifying the validity of the calibration result, and completing the calibration of the robot 7.

The utility model has the advantages that:

1. the stay wire sensor with variable length is adopted, so that the movement space of the robot is enlarged when data are collected, the movement of each joint of the robot is more sufficient, and the stronger data support of robustness is provided for structural parameter calculation, and the calibration operation is more flexible and portable.

2. The distance between two points of the tail end of the robot in the space can be accurately calculated according to the readings of the stay wire sensor and the inclination angle sensor, and the reliability and the precision of structural parameter calculation are improved.

3. The coordinate value of the robot tail end does not need to be measured, so that the operation steps are simplified, and the calibration efficiency is improved.

Drawings

FIG. 1 is a diagram of the pose of the device during data acquisition during calibration;

FIG. 2 is a schematic diagram of the length and angle of the robot end at poses i and j;

The reference numbers in the figures: 1-fixed platform, 2-magnetic gauge stand, 3-connecting rod, 4-stay wire sensor, 5-tilt sensor, 6-universal joint, 7-robot, 8-stay wire sensor cable, 9-robot cable, 10-tilt sensor cable, 11-computer.

Detailed Description

Example 1: as shown in fig. 1-2, a robot calibration system based on terminal incomplete coordinate information comprises a fixed platform 1, a magnetic gauge stand 2, a connecting rod 3, a stay wire sensor 4, a tilt sensor 5, a universal joint 6, a robot 7, a stay wire sensor cable 8, a robot cable 9, a tilt sensor cable 10 and a computer 11;

the magnetic gauge stand 2 is installed on the fixed platform 1 through magnetic force, the magnetic gauge stand 2 is connected with the stay wire sensor 4 through the connecting rod 3, the tail end of a stay wire of the stay wire sensor 4 is installed on a universal joint 6, an inclination angle sensor 5 is attached to the universal joint 6, the inclination angle sensor 5 moves along with the universal joint 6, and the universal joint 6 is installed on a robot 7; the stay wire sensor 4 and the tilt angle sensor 5 are respectively connected and communicated with a computer 11 through a stay wire sensor cable 8 and a tilt angle sensor cable 10, and the robot 7 is connected and communicated with the computer 11 through a robot cable 9; the computer 11 is used for acquiring the length of the stay wire sensor 4, the angle of the inclination angle sensor 5 and the joint rotation angle of the robot 7.

While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.

Claims (1)

1. A robot calibration system based on terminal incomplete coordinate information is characterized in that: the device comprises a fixed platform (1), a magnetic gauge stand (2), a connecting rod (3), a stay wire sensor (4), an inclination angle sensor (5), a universal joint (6), a robot (7), a stay wire sensor cable (8), a robot cable (9), an inclination angle sensor cable (10) and a computer (11);

the magnetic gauge stand (2) is installed on the fixed platform (1) through magnetic force, the magnetic gauge stand (2) is connected with the stay wire sensor (4) through the connecting rod (3), the tail end of a stay wire of the stay wire sensor (4) is installed on the universal joint (6), the inclination angle sensor (5) is attached to the universal joint (6), the inclination angle sensor (5) moves along with the universal joint (6), and the universal joint (6) is installed on the robot (7); the pull wire sensor (4) and the tilt angle sensor (5) are respectively connected with and communicated with a computer (11) through a pull wire sensor cable (8) and a tilt angle sensor cable (10), and the robot (7) is connected with and communicated with the computer (11) through a robot cable (9); the computer (11) is used for acquiring the stay wire length of the stay wire sensor (4), the angle of the inclination angle sensor (5) and the joint rotation angle of the robot (7).