CN115722978A

CN115722978A - Paraxial online correction method based on inverse kinematics

Info

Publication number: CN115722978A
Application number: CN202211420310.XA
Authority: CN
Inventors: 樊宜; 陆晓峰; 陈重义; 于仰韶
Original assignee: Xi'an Qinxuanhan Information Technology Co ltd
Current assignee: Xi'an Qinxuanhan Information Technology Co ltd
Priority date: 2022-11-15
Filing date: 2022-11-15
Publication date: 2023-03-03

Abstract

The application discloses a paraxial online correction method based on inverse kinematics, which belongs to the field of machine tool machining, and comprises the steps of firstly setting at least one paraxial vision system, secondly analyzing paraxial and obstacle avoidance in the machining process, selecting an optimal path, performing motion control through inverse kinematics in the machining process, setting a positioning calibration point for a machined object according to the paraxial vision system, performing error analysis by detecting the relation between the calibration point and the machined object in real time, and performing online correction and compensation on errors.

Description

Paraxial online correction method based on inverse kinematics

Technical Field

The application relates to the field of machine tool machining, in particular to an online paraxial correction method based on inverse kinematics.

Background

The invention provides a method for realizing an online correction function by a method of coordinate processing movement of a paraxial shaft and a main shaft, which aims to ensure that a processing technology meets processing requirements, improve processing precision and realize real-time online high-speed scanning and error compensation functions.

In the publication No. CN110640303A high-precision vision positioning system and the positioning calibration method thereof, a method for laser processing correction is designed, a paraxial vision system is arranged but fixed beside a processing spindle, and the problem is solved because the error caused by the uncalibrated galvanometer does not relate to the cooperative motion of the paraxial and the spindle.

Disclosure of Invention

Based on the defects of the prior art, the application provides an online paraxial correction method based on inverse kinematics, aiming at the problem of large deviation of the existing processing technology, which is characterized by comprising the following steps: and arranging at least one paraxial vision system beside the machining main shaft, planning the path of the paraxial motion, performing motion control on the machining process through inverse kinematics, and performing online correction according to the arranged paraxial vision system.

Optionally, the correction process includes setting a marker point and performing fixed-point target tracking on the marker point through the paraxial vision system.

Optionally, the real-time correction is determined by a change in distance to the index point and the processing object.

Further, the correction process may also be determined according to parameters such as the angle change of the mark point and the processing object.

Optionally, the process transmits data in real time via an industrial bus.

Optionally, the paraxial vision system comprises a paraxial motion device and a paraxial vision device.

Optionally, the paraxial vision device comprises at least one of a camera, a CCD camera, an LED lighting device.

Optionally, the path planning includes selecting the paraxial path that does not interfere with the main axis motion and an optimal path for obstacle avoidance.

Optionally, the path planning process includes automatically finding the index point by the paraxial according to the processing procedure.

Optionally, the inverse kinematics process includes setting an activation region of a calibration point near the object.

Optionally, the motion control includes setting the main axis as a constraint condition to calculate a motion parameter of the paraxial axis.

The beneficial effect of this application is: by arranging the paraxial vision system beside the main shaft for cooperative processing, under the condition of not interfering the main shaft processing, the positioning and online correction of a target point and a calibration point are realized by a paraxial vision positioning method and inverse kinematics algorithm motion control, and the processing precision is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a flow chart of an alternative paraxial online correction method according to an embodiment of the present application;

FIG. 2 is a schematic diagram of an alternative paraxial positioning architecture according to an embodiment of the present application;

FIG. 3 is a flow chart of a method for path planning according to an embodiment of the present application;

FIG. 4 is a flow chart of a method of performing motion based on inverse kinematics according to an embodiment of the present application;

FIG. 5 is a flow chart of a method for in-process error analysis according to an embodiment of the present application;

FIG. 6 is a schematic diagram of an online compensation process according to an embodiment of the present application;

wherein the figures include the following reference numerals:

1-a machine tool main shaft, 2-a paraxial motion device, 3-an image acquisition card, 4-an industrial personal computer, 5-a driving power supply, 6-a processing object and 7-a processing platform.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the described embodiments are merely exemplary of some, and not all, of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention provides an online paraxial correction method based on inverse kinematics, which comprises the following steps as shown in a flow chart of figure 1:

s101: determining a paraxial vision system, wherein the paraxial vision system comprises a paraxial motion device and a paraxial vision device;

s102: planning a processing path by calculating a paraxial motion path and analyzing an obstacle avoidance path;

s103: controlling the motion of the main shaft and the paraxial shaft through inverse kinematics;

s104: performing error analysis of the target point location according to a paraxial vision system;

s105: and compensating the real-time analysis error on line.

As shown in fig. 2, the system includes a machine tool spindle 1, a paraxial vision system 2, an image acquisition card 3, an industrial personal computer 4, a driving power supply 5, a processing object 6, and a processing platform 7, where the paraxial vision system 2 includes a paraxial motion device and a paraxial vision device. The system controls machining through the synergistic effect of the main shaft and the paraxial, a machining object is arranged on the machining platform, a paraxial A and a paraxial B are arranged beside the main shaft, a paraxial vision device CCD camera is arranged on the paraxial, a camera, an LED lighting device and the like can be arranged on the paraxial, and the system is not limited in the application. According to different processing technologies, a proper CCD camera is selected and matched, high-precision and ultrahigh-speed positioning is realized, and meanwhile, a plurality of CCD cameras can be loaded on a paraxial for identification, so that online high-speed real-time operation can be guaranteed. Real-time acquisition and transmission are transmitted to an industrial personal computer through an image acquisition card through a CCD camera on a paraxial, and a driving power supply is connected beside the industrial personal computer to supply power to the system and ensure the normal operation of the system.

The number of the paraxial shafts is set as required, and the embodiment of the application takes two shafts, namely the paraxial shaft A and the paraxial shaft B as an example, and is not particularly limited in the application.

Fig. 3 is a flowchart of a path planning method, in which, with the paraxial system shown in fig. 2, since the main shaft and the paraxial move cooperatively, in order to ensure that the main shaft is not interfered with for processing, and the paraxial vision system can keep detecting the processing process in real time during the movement of the main shaft, the movement trajectory has multiple paths, and in addition, during the processing, the shaft movement may encounter an obstacle, and at this time, path planning needs to be performed on the paraxial a and the paraxial B before the movement, so that the cooperative movement of the main shaft and the paraxial can be tracked to a fixed point target. And meanwhile, motion parameters such as speed, acceleration and the like are also considered, and the optimal path is selected by finally evaluating the motion time, wherein the path planning method is shown in fig. 3, only one path exists in the process of machining the spindle due to process requirements, N paths exist in the paraxial, the motion path of the paraxial is calculated, the obstacle avoidance is analyzed, the motion parameters of each path are calculated, M paths exist, the optimal path is selected by analyzing the factors such as the motion time and the like in the calculated path, and the path planning is finished at the moment, and the machining motion is performed according to the planned path.

FIG. 4 is a schematic diagram of controlling shaft motion via inverse kinematics according to an embodiment of the application, including the steps of: as shown in fig. 4, a plurality of calibration points are provided near the processing object, in the embodiment of the application, a circle is drawn on a 20 × 20mm board, firstly, the calibration point near the circular shape of the processing object is determined to be an active area, in the processing process of the area, the path of the main shaft is a unique path, in order to ensure that the motion of the paraxial shaft does not interfere with the processing of the main shaft and to realize the purpose of real-time detection and correction, the motion parameter of the main shaft is taken as the motion constraint condition, and the motion path of the calibration point of the paraxial shaft is planned, under the condition, the speed, the acceleration, the rotation angle of the motor and the like of the paraxial shaft are calculated by inverse kinematics, and the paraxial shaft is controlled to move by the inverse kinematics.

Fig. 5 is a flowchart of a method for performing error analysis by real-time detection of a paraxial motion CCD camera, wherein the method mainly realizes the identification of distortion and deviation of a calibration point, and mainly comprises the following steps: firstly setting a calibration point position and a calibration shape, secondly controlling a main shaft and a paraxial of a machine tool to process and control a current processing point according to an inverse kinematics algorithm, obtaining a calibration point parameter through analysis at the moment, identifying the deviation of the calibration point parameter and an actual processing object parameter in real time through a CCD camera, or comparing a required distance or a processing parameter by calculating whether the distance from the set calibration point to the processing object has the deviation, and correcting the deviation point in real time.

In order to ensure the instantaneity of the CCD paraxial positioning, an ethercat real-time industrial bus is adopted to transmit the acquired data.

In the embodiment of the application, the high-speed CCD camera is adopted, and the image data acquisition of millisecond level can be realized.

Fig. 6 is a schematic diagram of the basic application embodiment for performing online correction on real-time positioning errors, as shown in the figure, a circle needs to be drawn on a 10 × 10mm electronic board by using a laser processing technology, at this time, a calibration point is set by a paraxial vision system to obtain fig. 6a, where fig. 6a is a schematic diagram of requirements, and in an actual processing process, due to factors such as heating, a processing process deviation is caused, and the obtained circle cannot meet the requirements, that is, fig. 6b. At the moment, 4 calibration points are arranged, a circular shape is set according to a paraxial vision system, parameters of corresponding points are obtained according to coordinate axes, the distance from a calibration point to the circular shape is measured in real time according to a CCD paraxial system, when deviation occurs in the distance, the distance is transmitted to an industrial personal computer in real time, the processing process is controlled and corrected through calculation of the industrial personal computer, the processing process is returned to the track of a required processing path, similarly, the angle can be calculated, and in addition, real-time measurement and correction can be carried out through parameters such as the angle, and specific limitation is not imposed in the application. The machining process can be moved according to the set path plan based on the real-time correction to obtain fig. 6c.

The above-mentioned serial numbers of the embodiments of the present application are merely for description and do not represent the merits of the embodiments.

In the embodiments of the present application, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described apparatus embodiments are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or may be integrated into another system, or some features may be omitted, or may not be 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, units or modules, and may be in an electrical or other form.

The 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 position, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

The foregoing is only a preferred embodiment of the present application and it should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. An online paraxial correction method based on inverse kinematics is characterized by comprising the following steps: and arranging at least one paraxial vision system beside the machining main shaft, planning the path of the paraxial motion, performing motion control on the machining process through inverse kinematics, and performing online correction according to the arranged paraxial vision system.

2. The paraxial online correction method of claim 1, wherein the correction process comprises setting up a marker point and performing a fixed-point target tracking on the marker point by the paraxial vision system.

3. The calibration process according to claim 2, wherein the real-time calibration is determined by a change in distance between the calibration point and the processing object.

4. The paraxial online correction method of claim 1, wherein the process transmits data in real time over an industrial bus.

5. The paraxial online correction method of claim 1, wherein the paraxial vision system comprises a paraxial motion device and a paraxial vision device.

6. The paraxial vision system of claim 5, wherein the paraxial vision device comprises at least one of a camera, a CCD camera, an LED lighting device.

7. The paraxial online correction method of claim 1, wherein the path planning comprises selecting the paraxial path that does not interfere with the main axis motion and an optimal path for obstacle avoidance.

8. The path planning method according to claim 7, wherein the path planning process includes automatically finding the index point on the paraxial region according to the machining process.

9. The paraxial online correction method of claim 1, wherein the inverse kinematics control process comprises setting an activation region of a calibration point near the processing object.

10. The paraxial online correction method of claim 9, wherein the motion control comprises setting the principal axis to a constraint to calculate a motion parameter of the paraxial.