CN102554710B

CN102554710B - Device and method for measuring rotation angle error of rotary table of machine tool

Info

Publication number: CN102554710B
Application number: CN201210046988.6A
Authority: CN
Inventors: 傅建中; 何振亚; 姚鑫骅
Original assignee: 浙江大学
Priority date: 2012-02-28
Filing date: 2012-02-28
Publication date: 2014-11-05
Also published as: CN102554710A

Abstract

The invention discloses a device for measuring rotation angle error of a rotary table of a machine tool. The device comprises a support fixed on the rotary table; a reflecting mirror keeping running fit with the support; a magnetic field generator for generating a magnetic field; a magnetic field sensing member fixedly mounted on the reflecting mirror for keeping the direction of the reflecting mirror under the action of the magnetic field; and a laser ranging device for transmitting/receiving a laser beam to/from the reflecting mirror, and transforming the distance change of the reflecting mirror to the actual rotation angle of the rotary table. The device is simple in structure, convenient in measurement and easy to implementation, and can guide the direction of the reflecting mirror without contacting the reflecting mirror through the magnetic field and the magnetic field sensing member so as to facilitate distance measurement by the laser ranging device. The invention also discloses a method for measuring the rotation angle error of the rotary table of the machine tool. The method is convenient and accurate in measurement, and can calculate the error according to the actual rotation angle and a preset angle so as to provide the basis for error compensation of the machine tool.

Description

A kind of measurement mechanism of rotation angle error of rotary table of machine tool and method

Technical field

The present invention relates to measurement mechanism and the method field of rotation angle error of rotary table of machine tool, be specifically related to a kind of measurement mechanism and method of 5-shaft linkage numerical control rotation angle error of rotary table of machine tool.

Background technology

Along with the development of Modern Manufacturing Technology, precision processing technology is proposed to requirements at the higher level.The precision index of evaluating Digit Control Machine Tool mainly contains geometric positioning accuracy and machining accuracy etc., and they are affected by the factors such as machine tool structure, assembly precision, servo-drive system performance and external environment all.The precise treatment of lathe is the just active demand of the industrial circle such as automobile, electronics, medicine equipment, especially the basis of the modernization national defense industry such as Aero-Space, guided missile satellite, new weapon.Therefore, how effectively to improve machine finish and become current key issue urgently to be resolved hurrily.

5-shaft linkage numerical control lathe is the important tool that realizes the processing of complex curved surface parts precise high-efficiency, and it is widely used in the Precision Machining of the complex component such as turbine, blade.With respect to traditional three axle lathes, five-axis linkage machine tools structure is more complicated, can cause the problem of more precision aspect, and except the geometric error that three linear translation axles bring, two gyroaxises also can bring extra geometric error.Accurately to lathe geometric error, measurement is the important prerequisite that improves machine finish.At present, it is ripe that the measuring method of the geometric error of translation shaft has been tending towards, but the measurement of gyroaxis geometric error but rests on the exploratory stage.

Publication number is that the Chinese patent application of CN101913103A discloses a kind of method for measuring angular errors of rotating table of numerical control machine, by high-precision standard ball as measuring basis, standard ball is supported by base bracket, be fixed on workbench, infrared three-dimension workpiece probe is arranged on main shaft of numerical control machine tool, in order to the centre of sphere movement locus position coordinates of measurement standard ball, and obtain the angular errors of NC rotary table.Although the measuring method of the disclosure can calculate angular errors by standard ball and infrared three-dimension workpiece probe, but the precision that this infrared three-dimension workpiece probe is measured is not high, there is certain error in the centre of sphere movement locus position coordinates measurement for standard ball, the accuracy of the angular errors of rotating table of numerical control machine that this measuring method calculates is on the low side.

Publication number is the measuring method that the Chinese patent application of CN102001021A discloses a kind of 5-shaft linkage numerical control lathe backswing axle geometric error parameter value, the translation shaft interlock coordinate providing taking five-axis machine tool RTCP center cutter point control function is as measuring basis, adopt ball bar to measure respectively at least three position X under the different corners of gyroscopic pendulum moving axis, Y, the displacement error of Z direction, and identification calculates the geometric error of the each corner of gyroscopic pendulum moving axis according to described displacement error data processing, although all ten binomial geometric error parameters that this measuring method can complete detection 5-shaft linkage numerical control machine tool rotary swinging axle, but in this measuring method, need the data of measurement more, the process of measuring is also comparatively complicated, its simplicity needs further to be improved.

Summary of the invention

The invention provides a kind of measurement mechanism of rotation angle error of rotary table of machine tool, it is simple in structure, it is easy, easy to implement to measure.

A measurement mechanism for rotation angle error of rotary table of machine tool, comprising:

Support, is fixed on described rotary table;

Speculum, is rotatably assorted with described support;

Magnetic field generator, for launching magnetic field;

Magnetic field induction parts, are fixedly mounted on described speculum, for keep the direction of speculum under the effect in magnetic field;

Laser ranging system, for the speculum transmitting to described, reception laser beam, is converted to the change of distance of speculum the actual rotation angle of rotary table.

In the time that rotary table rotates, support on rotary table and speculum be rotation thereupon also, utilize magnetic field and magnetic field induction parts to guide the direction of speculum, make laser ranging system become fixed angle with speculum, the distance of speculum and laser ranging system changes, and obtains the actual rotation angle of rotary table by the change of distance value employing antitrigonometric function measuring after calculating.

Speculum is fixed on rotary table and with described support and is rotatably assorted by support, as preferably, described support comprises the magnetic base that is fixed on eccentric position on described rotary table, and being fixedly mounted on the column on this magnetic base, described speculum and described column are rotatably assorted.The material of described magnetic base need to can attract each other with rotary table, by magnetic base is set, magnetic base is fixed on rotary table very convenient, greatly improved the convenience that support uses, support can be fixed on rotary table eccentric position arbitrarily as required.

In order more accurately and more easily to obtain the distance of laser ranging system and speculum, as preferably, the laser beam of described laser ranging system transmitting is vertical with the minute surface of described speculum.Further preferably, described magnetic field induction parts are bar magnet, and the minute surface of the length direction of described magnetic field induction parts, described speculum is all parallel with magnetic direction.Bar-shaped magnet can lead better in magnetic field, keep the direction of speculum, and the length direction of magnetic field induction parts, the minute surface of speculum are parallel with magnetic direction, the minute surface that can more be conducive to speculum is vertical with the laser beam of laser ranging system reflection.

As preferably, be provided with the picture frame with strip groove being rotatably assorted with described support, described speculum is arranged on the bottom surface of this strip groove.This speculum embeds strip groove, not only facilitates the installation of speculum, and can make speculum fixation.Further preferably, described magnetic field induction parts are arranged on the top of the described picture frame with strip groove.Magnetic field induction parts not only do not affect speculum reflection laser beam, but also can keep better the minute surface of speculum vertical with the laser beam of laser ranging system transmitting.

Described magnetic field generator is the group of magnets that is arranged on described rotary table top.There is magnetic field by simple group of magnets is set, in the accuracy rating that can reach in magnetic field, ensure the direction of speculum.The coverage in magnetic field is generally greater than the zone of action of speculum.

Described laser ranging system can adopt prior art, comprise for the laser head of Emission Lasers bundle, for receive speculum reflection laser beam condenser, to transmitting and receiving laser control system that laser beam controls and for receiving the computer of actual rotation angle of calculated signals rotary table of laser control system input.

The present invention also provides a kind of measuring method of rotation angle error of rotary table of machine tool, measure easy, measure accurately, easy operating.

A measuring method for rotation angle error of rotary table of machine tool, comprises the following steps:

1) a rotating speculum is set on rotary table;

2) launch and accept laser beam to speculum at fixing point, measuring the first vertical range of this fixing point and speculum;

3) rotary table rotates a preset angles, in the time that rotary table rotates, by the magnetic field of fixed-direction, keeps the direction of speculum;

4) utilize second vertical range of launching and accepting laser beam measuring fixing point and speculum;

5), according to the poor actual rotation angle of calculating rotary table of the first vertical range and the second vertical range, obtain the deviation of actual rotation angle and preset angles.

Step 3) and step 4) in, the minute surface of described speculum is vertical with laser beam, and this mode is found range from easy, accurate.

Compared with prior art, tool of the present invention has the following advantages:

In the measurement mechanism of rotation angle error of rotary table of machine tool of the present invention, utilize magnetic field and magnetic field induction parts to speculum without contacting, just can guide the orientation of speculum, ensure the direction of speculum, make laser ranging system in measuring process, the minute surface of speculum is vertical with the laser beam of laser ranging system reflection all the time, thereby facilitates laser ranging system measuring distance.

The measurement mechanism of rotation angle error of rotary table of machine tool of the present invention is easy to install location, easy operating, easy to use, just can realize the measurement of the angular errors of the polarizers of big angle scope of rotary table by shirtsleeve operation, be conducive to promote the use of, there is good application prospect.

The measuring method of rotation angle error of rotary table of machine tool of the present invention, measuring process is easy, the range difference recording is calculated and just can be obtained actual rotation angle by antitrigonometric function, the accuracy of the actual rotation angle of measuring is higher, then according to actual rotation angle and preset angles calculation deviation, be the error compensation of the lathe foundation that affords redress.

Brief description of the drawings

Fig. 1 is the structural representation that is arranged on the measurement mechanism of the rotation angle error of rotary table of machine tool of the present invention on rotary table;

Fig. 2 is the structural representation of measurement mechanism medium-height trestle, magnetic field induction parts and the speculum of rotation angle error of rotary table of machine tool of the present invention;

Fig. 3 is the principle schematic of the measuring method of rotation angle error of rotary table of machine tool of the present invention;

Fig. 4 is the poor variation schematic diagram of vertical range in the measuring method of rotation angle error of rotary table of machine tool of the present invention;

Fig. 5 is the movement locus schematic diagram at the measuring method central post center of rotation angle error of rotary table of machine tool of the present invention;

Fig. 6 is the steps flow chart schematic diagram of the measuring method of rotation angle error of rotary table of machine tool of the present invention.

Detailed description of the invention

Below in conjunction with accompanying drawing, the invention will be further described.

As shown in Figure 1, for being arranged on the measurement mechanism of the rotation angle error of rotary table of machine tool of the present invention on rotary table 3 (C axle turntable), taking the angular errors around C axle rotation of rotary table 3 as example, table base 1, the rotary table 3 (C axle turntable) that is arranged on the A axle oscillating table 2 on table base 1 and is arranged on A axle oscillating table 2 is the parts on 5-shaft linkage numerical control lathe, and convenient understanding and explanation, mark X, Y, Z coordinate system, an arrow in coordinate system is the direction of rotation of A axle around X-axis rotation, another arrow in coordinate system is the direction of rotation of C axle around Z axis rotation.Speculum 13 that the measurement mechanism of rotation angle error of rotary table of machine tool of the present invention comprises the support that is fixed on rotary table 3, be rotatably assorted with support, for launch magnetic field magnetic field generator 4, be fixedly mounted on magnetic field induction parts 12 and laser ranging system on speculum 13.Magnetic field generator 4 is for being arranged on the group of magnets of rotary table 3 tops, and the field region of this group of magnets transmitting is greater than the rotary area of support.Magnetic field induction parts 12 for keeping the direction of speculum 13 under the effect in magnetic field.Laser ranging system comprises for the laser head 8 of Emission Lasers bundle 6, for receiving the condenser 7 of the laser beam 6 that speculum 13 reflects the front end face place that is arranged on laser head 8, to transmitting and receiving laser control system 10 that laser beam 6 controls and for receiving the computer 11 of actual rotation angle of the calculated signals rotary table 3 that laser control system 10 inputs.Between computer 11 and laser control system 10, laser control system 10 and laser head 8, all adopt cable 9 to be connected.The minute surface of speculum 13 is vertical with the laser beam 6 of laser ranging system transmitting.

As shown in Figure 2, be support, magnetic field induction parts 12 and speculum 13, support comprises column 14 and is arranged on that on rotary table 3, eccentric position is for the magnetic base 15 of vertical columns 14, magnetic base 15 is provided with the switch that magnetic is opened and disconnected.Column 14 is provided with the picture frame with strip groove being rotatably assorted with column 14, and speculum 13 embeds the bottom surface that is arranged on this strip groove, facilitates installation the fixation of speculum 13.Magnetic base 15 is provided with and fixing hole, and column 14 is threaded connection mode with fixing hole and fixes.The picture frame of strip groove and column 14 are rotatably assorted, and specifically can connect by employing activity hinge type.Magnetic field induction parts 12 are bar magnet, and the length direction of magnetic field induction parts 12, the minute surface of speculum 13 are parallel with magnetic direction.Speculum 13 is arranged on the top of the picture frame with strip groove, does not only affect speculum 13 and reflects laser beam 6, can also guide the direction of speculum 13 better.

As shown in Fig. 1, Fig. 3, Fig. 4, Fig. 5 and Fig. 6, a kind of measuring method of rotation angle error of rotary table of machine tool, comprises the following steps:

1) a rotating speculum 13 is set on rotary table 3;

2) launch and accept laser beam 6 to speculum 13 at fixing point, measuring the first vertical range of this fixing point and speculum 13;

3) rotary table 3 rotates a preset angles, in the time that rotary table 3 rotates, by the magnetic field of fixed-direction, keeps the angle of speculum 13;

4) utilize transmitting and accept laser beam 6 the second vertical range of measuring fixing point and speculum 3;

Step 3) and step 4) in, the minute surface of speculum 13 is vertical with laser beam 6;

5) calculate according to the difference of the first vertical range and the second vertical range the actual angle that rotary table 3 rotates, obtain the deviation of actual rotation angle and preset angles.

As shown in Figure 1 and Figure 2, measure while installation, the laser beam 6 of laser ranging system transmitting is parallel to X-Y plane, convenient to light for laser measuring device for measuring, preferably makes the laser beam 6 of laser ranging system transmitting be parallel to X-axis or Y-axis.In this concrete measuring method of implementing rotation angle error of rotary table of machine tool, make the laser beam 6 of laser ranging system transmitting be parallel to X-axis.The installation of support makes column 14 at rotary table 3 pivot offset or dish R, install for convenient, preferential rotary table 3 around the initial corner of the corner of C axle in 0 degree, the installation that is initial corner support in the time that 0 spends makes column 14 centers in Y-axis, rotary table 3 pivots are R along Y direction to the offset or dish at column 14 centers, establish this point for measuring start position.Speculum 13 can be parallel to X-Y plane around column 14 and rotate.

This measuring method is measured in conjunction with measurement mechanism of the present invention, when measurement, 5-shaft linkage numerical control lathe corner drive motors makes rotary table 3 rotate around C axle, direction of rotation is pressed in Fig. 1 in coordinate system around shown in the direction of arrow of Z axis, rotary table 3 around C axle rotate initial angle, taking column 14 centers in Y-axis as initial angle 0 is spent.Wherein, θ _ifor the preset angles (unit is angle) that rotary table 3 rotates around C axle, θ ' _ifor rotary table 3 is around the actual rotation angle (unit is angle) of C axle rotation.

Rotary table 3 slewing areas [0 °, 360 °] are divided into N decile, each angle of rotation increment Delta θ=360/N, N can need to set according to difference; The every rotation Δ of rotary table 3 θ, suspends 4 seconds, and laser ranging system is measured vertical range, above-mentioned steps repeatedly, until complete the measurement of whole rotary table 3 slewing areas, above-mentioned measuring process repeats 3 times, averages.As shown in Figure 3, in Fig. 3, dotted line 16 represents the movement locus at column 14 centers to the rotary course of support, speculum 13 and the picture frame with strip groove on rotary table 3, is illustrated in figure 4 different preset angles θ _iunder speculum 13 along the actual motion distance, delta L of X-direction _i; As shown in Figure 5, dotted line 16 represents the movement locus at column 14 centers, utilizes the poor Δ L of vertical range measuring _i, column 14 centers movement locus and antitrigonometric function, calculate the actual rotation angle θ ' of rotary table 3 _i, with rotary table 3 preset angles θ _isubtract each other, draw actual rotation angle θ ' _iwith preset angles θ _ideviation (unit is angle).Its calculating formula is as follows:

θ _i＝i×Δθ(i＝0，1，…N)???????????????????????(1)

${ΔL}_{i} = L_{θ_{0}} - L_{θ_{i}} = R {\sin θ}_{i}^{'} - - - (2)$

ε _i＝θ′ _i-θ _i???????????????????????????????????(3)

represent that rotary table 3 is θ in preset angles in the time that C axle rotates _ithe vertical range (unit is millimeter) that Shi Liyong laser ranging system is measured. represent that rotary table 3 is the vertical range (unit is millimeter) of utilizing laser ranging system to measure at 0 o'clock in the preset angles of C axle, measures the vertical range of start position.Solve actual rotation angle θ ' _itime, relate to solving of antitrigonometric function, respectively to θ i in rectangular coordinate system in four quadrants and reference axis eight kinds of situations discuss:

One, θ _iin four quadrants of rectangular coordinate system:

(1) work as θ _iin the time of first quartile, as 0 ° of < θ _iwhen 90 ° of <,

(2) work as θ _iin the time of the second quadrant, as 90 ° of < θ _iwhen 180 ° of <,

(3) work as θ _iin the time of third quadrant, as 180 ° of < θ _iwhen 270 ° of <, $θ_{i}^{'} = 180 + \arcsin (- \frac{L_{θ_{0}} - L_{θ_{i}}}{R});$

(4) work as θ _iin the time of fourth quadrant, as 270 ° of < θ _iwhen 360 ° of <, $θ_{i}^{'} = 360 - \arcsin (- \frac{L_{θ_{0}} - L_{θ_{i}}}{R});$

Two, θ _iin reference axis time, judge in conjunction with interpolation method and measurement vertical range:

(5) work as θ _i=90 ° time, if $\frac{ϵ_{i - 1} + ϵ_{i + 1}}{2} &GreaterEqual; 0,$ ? $θ_{i}^{'} = 180 - \arcsin (\frac{L_{θ_{0}} - L_{θ_{i}}}{R});$ If $\frac{ϵ_{i - 1} + ϵ_{i + 1}}{2} < 0,$ ? $θ_{i}^{'} = \arcsin (\frac{L_{θ_{0}} - L_{θ_{i}}}{R});$

(6) work as θ _i=180 ° time, if $L_{θ_{0}} - L_{θ_{i}} &GreaterEqual; 0,$ ? $θ_{i}^{'} = 180 - \arcsin (\frac{L_{θ_{0}} - L_{θ_{i}}}{R});$ If $L_{θ_{0}} - L_{θ_{i}} < 0,$ ? $θ_{i}^{'} = 180 + \arcsin (- \frac{L_{θ_{0}} - L_{θ_{i}}}{R});$

(7) work as θ _i=270 ° time, if $\frac{ϵ_{i - 1} + ϵ_{i + 1}}{2} &GreaterEqual; 0,$ ? $θ_{i}^{'} = 360 - \arcsin (- \frac{L_{θ_{0}} - L_{θ_{i}}}{R});$ If $\frac{ϵ_{i - 1} + ϵ_{i + 1}}{2} < 0,$ ? $θ_{i}^{'} = 180 + \arcsin (- \frac{L_{θ_{0}} - L_{θ_{i}}}{R});$

(8) work as θ _i=360 ° time, if $L_{θ_{0}} - L_{θ_{i}} &GreaterEqual; 0,$ ? $θ_{i}^{'} = 360 + \arcsin (\frac{L_{θ_{0}} - L_{θ_{i}}}{R});$ If $L_{θ_{0}} - L_{θ_{i}} < 0,$ ? $θ_{i}^{'} = 360 - \arcsin (- \frac{L_{θ_{0}} - L_{θ_{i}}}{R});$

Wherein, (1), in (8), the angle obtaining by arcsin function is more than or equal to 0 ° and be less than or equal to 90 °, i.e. 0 °≤arcsinx≤90 °.Can solve actual rotation angle θ ' by above-mentioned discussion _ithereby, can obtain angular errors ε _i=θ ' _i-θ _i.In 8 kinds of above-mentioned situations, computational process can arrange corresponding program and realize in computer 11.

Claims

1. a measurement mechanism for rotation angle error of rotary table of machine tool, is characterized in that, comprising:

Support, be fixed on described rotary table (3), described support comprises the magnetic base (15) that is fixed on the upper eccentric position of described rotary table (3), and is fixedly mounted on the column (14) on this magnetic base (15);

Speculum (13), is rotatably assorted with described support, and described speculum (13) is rotatably assorted with described column (14);

Magnetic field generator (4), for launching magnetic field;

Magnetic field induction parts (12), be fixedly mounted on described speculum (13), for keep the direction of speculum (13) under the effect in magnetic field, described magnetic field induction parts (12) are bar magnet, and the minute surface of the length direction of described magnetic field induction parts (12), described speculum (13) is all parallel with magnetic direction;

Laser ranging system, for launching to described speculum (13), receive laser beam (6), the change of distance of speculum (13) is converted to the actual rotation angle of rotary table (3), described laser ranging system comprises for the laser head of Emission Lasers bundle (6) (8), be used for the condenser (7) of the laser beam (6) that receives speculum (13) reflection, to transmitting and receiving laser control system (10) that laser beam (6) controls and for receiving the computer (11) of actual rotation angle of calculated signals rotary table (3) of laser control system (10) input,

The laser beam (6) of described laser ranging system transmitting is vertical with the minute surface of described speculum (13).

2. the measurement mechanism of rotation angle error of rotary table of machine tool according to claim 1, is characterized in that, is provided with the picture frame with strip groove being rotatably assorted with described support, and described speculum (13) is arranged on the bottom surface of this strip groove.

3. the measurement mechanism of rotation angle error of rotary table of machine tool according to claim 2, is characterized in that, described magnetic field induction parts (12) are arranged on the top of the described picture frame with strip groove.

4. the measurement mechanism of rotation angle error of rotary table of machine tool according to claim 1, is characterized in that, described magnetic field generator (4) is for being arranged on the group of magnets of described rotary table (3) top.

5. for a measuring method for the measurement mechanism of rotation angle error of rotary table of machine tool described in claim 1, it is characterized in that, comprise the following steps:

1) a rotating speculum (13) is set on rotary table (3);

2) launch and accept laser beam (6) to speculum (13) at fixing point, measuring the first vertical range of this fixing point and speculum (13);

3) rotary table (3) rotates a preset angles, in the time that rotary table (3) rotates, by the magnetic field of fixed-direction, keeps the direction of speculum (13);

4) utilize transmitting and accept laser beam (6) the second vertical range of measuring fixing point and speculum (13);

5), according to the poor actual rotation angle of calculating rotary table (3) of the first vertical range and the second vertical range, obtain the deviation of actual rotation angle and preset angles.

6. measuring method according to claim 5, is characterized in that step 2) and step 4) in, the minute surface of described speculum (13) is vertical with laser beam (6).