CN112497192A - Method for improving teaching programming precision by adopting automatic calibration mode - Google Patents

Abstract

The invention discloses a method for improving teaching programming precision by adopting an automatic calibration mode. And (3) carrying out simulated operation according to the scattered track, measuring an execution result when the simulation operation process moves to a measuring point, acquiring the deviation between the simulated operation result and the actual track, and calibrating the scattered track by using the deviation so as to acquire an actual operation track file which is calibrated and can fit the contour line of the machined workpiece with high precision. The invention has simple arrangement and simple and convenient operation; for workpiece teaching, only the point-to-point operation of key points (a straight line head and tail point, a head point, a middle point and a tail point of an arc) is needed to be completed, so that a large amount of manual operation is reduced; the actual measurement operation is automatically completed by the manipulator, so that the programming point aligning efficiency can be effectively improved; the machining precision can be greatly improved on the premise of ensuring the programming efficiency.

Description

Method for improving teaching programming precision by adopting automatic calibration mode

Technical Field

The invention relates to the technical field of teaching programming, in particular to a method for improving teaching programming precision by adopting an automatic calibration mode.

Background

Teach programming refers to the process of programming the robot to perform the desired actions and recording the key points to form the task program by manually guiding the robot end effector, or manually guiding the mechanical simulation device, or using a teach pendant (a hand held device connected to the control system to program or move the robot).

A task program is a set of motion and auxiliary function instructions that determine the particular intended task for the robot, and such programs are typically programmed by a user using teaching programming or generated off-line programming. During teaching programming, a frequently-adopted method is to place a product to be processed on a working table, then control movement of each movement axis of a manipulator, guide an end effector of the manipulator to move close to the surface of the product to be processed and collect key coordinate points of a track, approximately split the outer contour of a workpiece into a plurality of sections of straight lines, record the situation of the approximate outer contour track of the workpiece one by one in a point-to-point mode, and generate an operation program.

There are a number of repeated teaching point-to-point operations in forming a task program by teaching programming. Meanwhile, in the process that the end effector of the manual guide manipulator is close to the surface of a product to be processed, particularly when a workpiece rotates on an XOZ or YOZ plane to process the outer contour of the product, the teaching speed is set too slowly along with the rotation of the workpiece and the descending of a Z axis, the programming efficiency is influenced, and the teaching speed is set too fast, so that the accident that the end effector collides the workpiece is easily caused. Meanwhile, if the contour line of the workpiece is not split uniformly, the point alignment is not accurate, and the problem of insufficient precision can be caused because the cutter cannot be attached to the surface of the workpiece accurately during machining. Therefore, a method is needed, which obtains an approximate contour track through point-to-point operation as few as possible, then runs according to the approximate contour track, measures the actual deviation of the track running process through a distance measuring sensor in the running process, calibrates the approximate contour track generated by teaching programming by using measured deviation data, obtains the accurate track of the outer contour of the workpiece, and then performs actual processing control. By using the technology, the programming efficiency can be ensured, and the accurate processing of the workpiece can also be ensured.

During teaching programming, the machining trajectory is generally fitted to the workpiece contour in a teaching-to-point manner. It has the following disadvantages: (1) the higher the scattering precision of the outer contour line of the workpiece is, the closer the actual running track is to the actual contour of the workpiece, the higher the processing precision is; however, teaching is inefficient as the time cost for pointing is increased. (2) When the point-to-point operation is actually taught, if the end effector of the manipulator cannot be tightly attached to the outer contour of the workpiece or the selected teaching point cannot correctly select the key point of the track, the processing precision can be greatly reduced. (3) Because of the inconsistent proficiency of operators, the greater the number of point-aligning operations, the greater the probability of an end effector-product collision event.

Disclosure of Invention

In view of the above, in order to solve the above problems in the prior art, the present invention provides a method for improving teaching programming precision by using an automatic calibration method, which can greatly improve processing precision on the premise of ensuring programming efficiency.

The invention solves the problems through the following technical means:

a method for improving teaching programming precision by adopting an automatic calibration mode comprises the following steps:

s1, obtaining an approximate contour line track through teaching programming;

s2, scattering the track and generating a measuring point;

s3, performing simulated operation according to the scattered track, and measuring an execution result when the test object moves to a measuring point in the process of simulated operation to obtain the deviation between the simulated operation result and the actual track;

and S4, calibrating the scattered track by using the deviation to obtain an actual running track file which can be used for fitting the contour line of the workpiece with high precision after calibration.

Further, step S1 is specifically:

and manually carrying out profile teaching according to the end points of the straight line and the circular arc to obtain an approximate motion track.

Further, the breaking of the contour line in step S2 is divided into two main categories: straight lines and arcs; the straight line is scattered according to the set unit length, and the line segments which are less than the unit length are calculated according to the unit length; the arc is scattered according to the set unit angle, and a section of unit arc is formed when the unit angle is less than the unit angle; one unit circular arc is divided into two straight lines for calibration according to the scattered circular arc starting point, the scattered circular arc middle point and the scattered circular arc tail point.

Further, the process of breaking up the arc in step S2 is:

firstly, taking out a curve part in an approximate contour, and breaking the curve part into a series of unit arcs according to a set arc breaking angle; calculating the coordinates of the start point, the middle point and the tail point of the unit arc, and calculating to generate a broken Line segment approximation replacing an arc track consisting of Line1 and Line 2; and respectively calibrating the end points of the unit straight line and the circular arc as measuring points according to the scattered contour track.

Further, step S2 is specifically:

according to the unit scattering length of the straight line and the unit scattering angle of the circular arc, the approximate contour line is scattered into a set of the unit straight line and the circular arc; meanwhile, the relevant end points of the straight line and the circular arc are marked as measuring points.

Further, step S3 is specifically:

and controlling the manipulator to run according to the broken teaching track, and executing the measurement script and controlling the measurement sensor to obtain the deviation value between the approximate contour line of the measurement point and the actual contour line when the manipulator runs to the measurement point.

Further, step S4 is specifically:

the approximate contour line is a motion track of the manipulator after primary teaching; the actual contour line is the contour line of the workpiece; therefore, the actual motion track of the manipulator has certain deviation from the outer contour of the workpiece, and deviation calibration is required; when deviation calibration is carried out, firstly, the approximate contour line is scattered into a plurality of line segments, point-to-point measurement is automatically carried out on each end point of the scattered line segments in the simulation operation process to obtain a deviation value, and then according to a formula:

the actual coordinate of the workpiece at the point is the approximate contour line coordinate of the point plus the deviation value

And the measurement of the whole section of contour line is completed, so that the accurate fitting from the approximate contour line to the outer contour of the workpiece can be completed.

Compared with the prior art, the invention has the beneficial effects that at least:

1. the setting is simple, and the operation is simple and convenient.

2. For workpiece teaching, only the point-to-point operation of key points (the head and tail points of a straight line, the head point, the middle point and the tail point of an arc) is required to be completed, and a large amount of manual operation is reduced.

3. The actual measurement operation is automatically completed by the manipulator, and the programming point aligning efficiency can be effectively improved.

4. The machining precision can be greatly improved on the premise of ensuring the programming efficiency.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a general flow chart of the method of the present invention for improving teaching programming accuracy using auto-calibration;

FIG. 2 is a flow chart of the contour line break-up of the present invention;

FIG. 3 is a comparison of the approximate contour line after calibration and the actual contour line of the present invention;

FIG. 4 is a schematic diagram of the approximate contour line broken into segments according to the present invention;

FIG. 5 is a schematic view of the straight line break-up of the present invention;

FIG. 6 is a schematic view of the breaking up of the arc of the invention;

FIG. 7 is a flow chart of the present invention for breaking up the arc;

FIG. 8 is a flow chart of the invention calibrating as a measurement point.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments of the present invention belong to the protection scope of the present invention.

As shown in FIG. 1, the invention provides a method for improving teaching programming precision by adopting an automatic calibration mode, which obtains an approximate contour line track through teaching programming, and performs scattering operation on the track to generate a measuring point. And (3) carrying out simulated operation according to the scattered track, measuring an execution result when the simulation operation process moves to a measuring point, acquiring the deviation between the simulated operation result and the actual track, and calibrating the scattered track by using the deviation so as to acquire an actual operation track file which is calibrated and can fit the contour line of the machined workpiece with high precision.

The specific single-axis calibration flow comprises the following steps:

1. generation of approximate contour line: and manually carrying out profile teaching according to the end points of the straight line and the circular arc to obtain an approximate motion track.

2. Scattering of approximate contour lines and calibrating reference points: and (4) according to the unit scattering length of the straight line and the unit scattering angle of the circular arc, scattering the approximate contour line into a set of the unit straight line and the circular arc. Meanwhile, the relevant end points of the straight line and the circular arc are marked as measuring points, as shown in fig. 2.

3. Automatically measuring and acquiring deviation data in the simulation operation process: and controlling the manipulator to run according to the broken teaching track, and executing the measurement script and controlling the measurement sensor to obtain the deviation value between the approximate contour line of the measurement point and the actual contour line when the manipulator runs to the measurement point.

4. And (3) difference data operation: and fitting the approximate contour line by using the deviation data to obtain the accurate contour of the actual workpiece.

The actual calibration process is shown in fig. 3, wherein the approximate contour line is the motion track of the manipulator after the initial teaching; the actual contour line is the contour line of the workpiece. Therefore, the actual motion track of the manipulator has a certain deviation from the outer contour of the workpiece, and deviation calibration is required. When deviation calibration is performed, firstly, the approximate contour line is broken up into a plurality of line segments as shown in fig. 4, point-to-point measurement is automatically performed on each end point of the broken-up line segments in the simulation operation process to obtain a deviation value, and then according to a formula:

the actual coordinate of the workpiece at the point is the approximate contour line coordinate of the point plus the deviation value

And the measurement of the whole section of contour line is completed, so that the accurate fitting from the approximate contour line to the outer contour of the workpiece can be completed.

The breaking up of the contour lines can be divided into two main categories: straight line, circular arc. The straight line is scattered according to the set unit length, and the line segments which are less than the unit length are calculated according to the unit length. The straight line scattering process is not repeated herein, and is shown by the illustration only, as shown in fig. 5.

As shown in fig. 6, the arc is broken up according to the set unit angle, and a segment of unit arc is formed by calculating the unit angle less than the unit angle. One unit circular arc is divided into two straight lines for calibration according to the scattered circular arc starting point, the scattered circular arc middle point and the scattered circular arc tail point.

The arc breaking process is shown in fig. 7, and the arc breaking process comprises the following steps: firstly, the curve part in the approximate contour is taken out and is broken up into a series of unit arcs according to the set arc breaking angle. And the coordinates of the start point, the middle point and the tail point of the unit arc are obtained, and the approximate broken Line segment replacing arc tracks which are composed of Line1 and Line2 Line segments are calculated and generated. And respectively calibrating the end points of the unit straight line and the circular arc as measuring points according to the scattered contour track. The flow chart for calibrating the measurement points is shown in FIG. 8.

The invention has the following advantages:

1. the setting is simple, and the operation is simple and convenient.

2. For workpiece teaching, only the point-to-point operation of key points (the head and tail points of a straight line, the head point, the middle point and the tail point of an arc) is required to be completed, and a large amount of manual operation is reduced.

3. The actual measurement operation is automatically completed by the manipulator, and the programming point aligning efficiency can be effectively improved.

4. The machining precision can be greatly improved on the premise of ensuring the programming efficiency.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (7)

1. A method for improving teaching programming precision by adopting an automatic calibration mode is characterized by comprising the following steps:

s1, obtaining an approximate contour line track through teaching programming;

s2, scattering the track and generating a measuring point;

s3, performing simulated operation according to the scattered track, and measuring an execution result when the test object moves to a measuring point in the process of simulated operation to obtain the deviation between the simulated operation result and the actual track;

and S4, calibrating the scattered track by using the deviation to obtain an actual running track file which can be used for fitting the contour line of the workpiece with high precision after calibration.

2. The method for improving teaching programming accuracy by automatic calibration according to claim 1, wherein the step S1 is specifically as follows:

and manually carrying out profile teaching according to the end points of the straight line and the circular arc to obtain an approximate motion track.

3. The method for improving teaching programming accuracy by automatic calibration according to claim 1, wherein the break-up of the contour line in step S2 is divided into two categories: straight lines and arcs; the straight line is scattered according to the set unit length, and the line segments which are less than the unit length are calculated according to the unit length; the arc is scattered according to the set unit angle, and a section of unit arc is formed when the unit angle is less than the unit angle; one unit circular arc is divided into two straight lines for calibration according to the scattered circular arc starting point, the scattered circular arc middle point and the scattered circular arc tail point.

4. The method for improving teaching programming accuracy by automatic calibration according to claim 3, wherein the process of breaking up the circular arc in step S2 is as follows:

firstly, taking out a curve part in an approximate contour, and breaking the curve part into a series of unit arcs according to a set arc breaking angle; calculating the coordinates of the start point, the middle point and the tail point of the unit arc, and calculating to generate a broken Line segment approximation replacing an arc track consisting of Line1 and Line 2; and respectively calibrating the end points of the unit straight line and the circular arc as measuring points according to the scattered contour track.

5. The method for improving teaching programming accuracy by automatic calibration according to claim 1, wherein the step S2 is specifically as follows:

according to the unit scattering length of the straight line and the unit scattering angle of the circular arc, the approximate contour line is scattered into a set of the unit straight line and the circular arc; meanwhile, the relevant end points of the straight line and the circular arc are marked as measuring points.

6. The method for improving teaching programming accuracy by automatic calibration according to claim 1, wherein the step S3 is specifically as follows:

and controlling the manipulator to run according to the broken teaching track, and executing the measurement script and controlling the measurement sensor to obtain the deviation value between the approximate contour line of the measurement point and the actual contour line when the manipulator runs to the measurement point.

7. The method for improving teaching programming accuracy by automatic calibration according to claim 1, wherein the step S4 is specifically as follows:

the approximate contour line is a motion track of the manipulator after primary teaching; the actual contour line is the contour line of the workpiece; therefore, the actual motion track of the manipulator has certain deviation from the outer contour of the workpiece, and deviation calibration is required; when deviation calibration is carried out, firstly, the approximate contour line is scattered into a plurality of line segments, point-to-point measurement is automatically carried out on each end point of the scattered line segments in the simulation operation process to obtain a deviation value, and then according to a formula:

the actual coordinate of the workpiece at the point is the approximate contour line coordinate of the point plus the deviation value

And the measurement of the whole section of contour line is completed, so that the accurate fitting from the approximate contour line to the outer contour of the workpiece can be completed.

Images