CN101797702B - Device for measuring position precision of digital control turntable by using laser angle interferometer and measuring method - Google Patents

Abstract

The invention relates to a device for measuring the position precision of a digital control turntable by using a laser angle interferometer, which solves the problem of complex structure, labor consuming and time consuming of correcting a reflector constant in a traditional device. A main shaft (22) is fixedly connected with a terminal pad (21), a bearing seat (8) is fixedly connected with a tested digital control turntable, an attracting disk (16) and a disk gear (18), a magnet (6) is fixedly connected with the terminal pad (21) and is opposite to the attracting disk (16), a step motor seat (19) is fixedly connected with the terminal pad (21), the shaft end of a stepping motor (5) is fixedly connected with a gear (17) engaged with the disk gear (18), an angle reflector (3) is fixedly connected with the terminal pad (21), a laser beam emitted by a laser head (1) is divided into two paths through an angle interference module (2) and the two paths are respectively ejected to the angle reflector (3), the light beam returned by the angle reflector (3) is ejected to the laser head (1) through the angle interference module (2), a light beam signal is sent to a computer (12) through a control panel (11) and is converted to an angle value, a receiver (9) is connected with the computer (12) connecting the control panel (11), and the control panel (11) is connected with the stepping motor (5) and the magnet (6).

Description

The device of measuring position precision of digital control turntable by using laser angle interferometer and measuring method thereof

Technical field:

The present invention is the expanded application of laser angle interferometer for adopting the device of measuring position precision of digital control turntable by using laser angle interferometer, is used to detect the positional precision of Digit Control Machine Tool numerical control rotating platform.

Background technology:

Laser angle interferometer measuring principle such as Fig. 1; The laser beam that laser head 1 sends is divided into two-way in angle intervention module 2; Two angles idol prisms in the directive angled mirrors 3 respectively, when angled mirrors when E turns to the F position from the home position, corresponding corner is α; δ takes place the laser beam light path of two angle idol prisms changes, and the anglec of rotation α of angled mirrors can be obtained by following formula:

α＝arcsin(δ/A)

Following formula is the laser angle interferometer measure equation.A is the angled mirrors constant, is the distance of two angle idol prism awl points, and laser angle interferometer records optical path difference δ, calculates angle value α according to following formula.

With laser angle interferometer energy measurement numerical control rotating platform not, reason is following:

1, measurement category is little: in arcsin function, curvature tended towards stability when angle increased because of (1), and the resolution ratio of measurement reduces; (2) along with the departing from also of increase laser beam that take measurement of an angle strengthens, when increasing to laser beam disengaging angled mirrors when taking measurement of an angle, the laser angle interferometer cisco unity malfunction.The range of general laser angle interferometer is less than ± 10 °.

2, the error of angled mirrors constant A can cause big measure error, and is as shown in Figure 2, because the error (corresponding diagram 2 curves 1 and 2) of angled mirrors constant A makes identical change in optical path length δ obtain different angular surveying α as a result ₁And α ₂

The following formula differential is got:

$\mathrm{d\α}=\frac{-\mathrm{\δdA}}{A\sqrt{A^2-{\mathrm{\δ}}^2}}\≈\frac{-\mathrm{\αdA}}{A}$

If A=30mm, in the time of can calculating in α=10 °, if the error of angled mirrors constant A is dA=0.1mm, then causing measure error is d α=120 ".

The processing of angled mirrors and assembly precision, installation and use scene temperature etc. all can influence the variation of angled mirrors constant A value, and therefore this error effect is very important in measurement.

Need solve two problems with measuring position precision of digital control turntable by using laser angle interferometer: the one, range extension can be accomplished many circle complete cycles and detect; The 2nd, collimation angle speculum constant A is to improve certainty of measurement before each the measurement.

The method that Britain Renishaw company adopts multiteeth indexing table to combine with laser angle interferometer has been developed the annex of measuring position precision of digital control turntable by using; Operation dedicated program collimation angle speculum constant A before measuring; In measuring process; Adopt angled mirrors range infinitely to be enlarged, but, make and install the light difficulty because the last fluted disc of multiteeth indexing table need move up and down together with angled mirrors with the method that last fluted disc rotates with respect to the same speed of tested numerical control rotating platform rightabout; And complex structure, manufacturing cost is higher.

Relevant method Chengdu Tool Research Institute with measuring position precision of digital control turntable by using laser angle interferometer has declared two patents:

" laser angle interferometry system and the measuring method thereof that have standard angle rotating platform ", open (bulletin) number: CN101236076;

" the multiteeth indexing table device that table top does not go up and down ", open (bulletin) number: CN101561265.

The former proposes to have saved multiteeth indexing table with the method for standard angle as correction speculum constant A; The latter proposed the multiteeth indexing table that table top does not go up and down, and solved because last fluted disc moves up and down the installation that causes to the light difficulty.But the method for two patent propositions all needs before measurement, proofread and correct the speculum constant A, wastes time and energy.

Summary of the invention:

The objective of the invention is propose to adopt wholecircle error closure principle, efficiently solve the device of measuring position precision of digital control turntable by using laser angle interferometer of the instant calibration problem of angled mirrors constant A.

The present invention is achieved in that

The device of measuring position precision of digital control turntable by using laser angle interferometer of the present invention, main shaft 22 is connected with terminal pad 21, and main shaft 22 is positioned at the bearing 30 of bearing block 8; Main shaft 22 is concentric with tested numerical control rotating platform 10, and bearing block 8 is connected with tested numerical control rotating platform 10, is connected with adhesive disk 16; Be connected with dish gear 18, electromagnet 6 is connected with terminal pad 21, and is relative with adhesive disk 16; Stepper motor seat 19 is connected with terminal pad 21, and the axle head of stepper motor 5 and gear 17 are connected, gear 17 and 18 engagements of dish gear; Angled mirrors 3 is connected with terminal pad 21, and terminal pad 21 is connected with bearing block 8 through stop screw 32, laser head 1 and angle intervention module 2 fixed-site; The laser beam that laser head 1 sends is divided into two-way directive angled mirrors 3 respectively through angle intervention module 2, and angled mirrors 3 Returning beams are through angle intervention module 2 directive laser heads 1, and its signal send computer 12 again and converts angle value into through control electronic box 11; LASER Light Source 7 is fixed in bearing block 8, and receiver 9 is installed on the fixed position and aims at LASER Light Source 7, and the output of receiver 9 is connected with computer 12; The output of computer 12 is connected with control electronic box 11, and control electronic box 11 is connected with electromagnet 6 with stepper motor 5.

Adhesive disk 16 is connected with thin discs 15, and thin discs 15 is connected with bearing block 8.

Cushion cover 13 is connected with bearing block 8, and mid-game 29 is connected with cushion cover 13, and the location cylindrical of mid-game 29 is arranged in the hole of tested numerical control rotating platform 10 centres of gyration, and main shaft 22 is concentric with this hole.

The measurement device position precision of digital control turntable by using, its measuring process is following:

According to the examination criteria GB-17421.2-2000 of Digit Control Machine Tool regulation, to numerical control revolving table position accuracy detection need be suitable in complete cycle according to certain interval, counterclockwise measure several weeks.

If measure m week, the assay intervals Δ, then the detection number of times in weekly is the n=360/ Δ, measuring process is following in the direction of the clock.

(1) measurement mechanism that will be 4 by angled mirrors 3, main shaft, bearing block 8, stepper motor 5, electromagnet 6, LASER Light Source 7 etc. constitutes is fixed on the tested numerical control rotating platform 10, makes tested numerical control rotating platform 10 coaxial with the main shaft of measurement mechanism;

(2) in the fixed position receiver 9 is installed, when making tested numerical control rotating platform 10 rotations, the light beam that LASER Light Source 7 sends can inswept receiver 9;

(3) laser head 1, angle intervention module 2 are installed, rotating spindle is 4, makes the surface of angled mirrors 3 vertical with incoming laser beam, computer 12 zero clearings;

(4) measure beginning, it is 4 that electromagnet 6 unclamps main shaft, and stepper motor 5 control main shafts are 4 to be rotated counterclockwise Δ/2;

(5) electromagnet 6 again with main shaft be 4 with bearing block 8 locked, computer 12 is write down angular readings a (1,1);

(6) tested numerical control rotating platform 10 Δ that turns clockwise, computer 12 is write down angular readings b (1,1);

(7) electromagnet 6 unclamps main shaft 4 and bearing block 8, is rotated counterclockwise Δ by stepper motor 5 control main shafts 4;

(8) repeat (5)-(7) step n time, computer 12 write down the 1st circle value of taking measurement of an angle a (1, n) and b (1, n), accomplish the 1st and enclose measurement;

(9) in the 1st circle is measured, produce during the light beam that LASER Light Source 7 sends is inswept receiver 9 one full circle week pulse signal sampling with respect to this assay intervals starting point a (1, n ₀) angle value c (1,1).

(10) repeat (5)-(9) step m time, computer 12 write down three-dimensional array a (m, n), b (m, n) and c (m, s); Measurement finishes.

(11) counter-clockwise direction is measured and is undertaken by above-mentioned steps (4)-(10), and just direction of rotation is reverse.

M=1 wherein ... M, n=1 ... N, s=1 ... M-1,

n ₀Assay intervals position for full circle week pulse signal place.

After above-mentioned measurement, computer 12 obtains instantaneous pin, counter-clockwise two groups of three-dimensional array:

A (m, n): at the angle value of the starting point of m week n interval measurement;

B (m, n): at the angle value of the terminating point of m week n interval measurement;

(m, s): in m week s interval, the full circle pulse signal sampling that receiver 9 produces is with respect to this assay intervals starting point a (m, n for c ₀) angle value.

(12) computer carries out data, and step is following:

The measured value y of each assay intervals Δ (m, n):

y(m，n)＝b(m，n)-a(m，n) (1)

Angle and z between all pulse signals of per two adjacent full circle _s:

$z_s=\underset{n_0+1}{\overset{n}{\mathrm{\Σ}}}y(m,n-n_0)+\underset{1}{\overset{n_s}{\mathrm{\Σ}}}y(m+1,n_s-1)+y(m,n_0)-c(m,s)+c(m+1,s)---\left(2\right)$

N wherein _s=1 ... N ₀

Between two adjacent full circle week pulse signals angle and mean value z _s:

$\stackrel{\‾}{z_s}=\frac{\underset{1}{\overset{s}{\mathrm{\Σ}}}{z}_s}{s}---\left(3\right)$

According to wholecircle error closure principle, calculate the angle correct factor beta:

β＝3600×360/z _s (4)

The error amount e of each assay intervals Δ (m, n):

e(m，n)＝y(m，n)×β-Δ (5)

During complete cycle is measured, each assay intervals with respect to the error amount δ that measures starting point (m, n):

$\left\{\begin{array}{c}\mathrm{\δ}(m,n)=e(m,1)\\ \mathrm{\δ}(m,n)=\mathrm{\δ}(m,n-1)+e(m,n)\end{array}\right\}---\left(6\right)$

Computer (12) is according to the regulation of the examination criteria GB-17421.2-2000 of Digit Control Machine Tool; Calculate clockwise, the counter-clockwise every circle complete cycle of tested numerical control rotating platform (10) and measure each assay intervals with respect to the error amount δ (m that measures starting point; N) after, obtain the positioning accuracy and the repetitive positioning accuracy of numerical control rotating platform (10) again by standard code.

LASER Light Source 7 can be installed in the optional position of tested numerical control rotating platform 10 rotary table tops.

In measuring process, the initial measurement position is the half the of assay intervals, and promptly measuring initial point is Δ/2, makes the former point symmetry of measuring distance with respect to the laser angle interferometer measure equation.

Advantage of the present invention is following:

The present invention adopts the device of measuring position precision of digital control turntable by using laser angle interferometer, and the speculum constant A is calibrated immediately during measurement, and certainty of measurement is high, and apparatus structure is simple, and not restriction of range.

Description of drawings:

Fig. 1 is a laser angle interferometer measuring principle sketch map.

Fig. 2 changes the influence to measuring for the angled mirrors constant A.

Fig. 3 is a system diagram of the present invention.

Fig. 4 is this bright front view.

Fig. 5 is the right view of Fig. 4.

This embodiment of tool:

The device of laser angle interferometer measurement numerical control rotating platform is as shown in Figure 3.Main shaft be 4 and 8 of bearing blocks can coaxial relative rotation; Laser head 1 and angle intervention module 2 fixed-site; The laser beam that is sent by laser head 1 is divided into two-way directive angled mirrors 3 respectively through angle intervention module 2; Angled mirrors 3 Returning beams are through angle intervention module 2 directive laser heads 1, and its signal send computer (12) again and converts angle value into through control electronic box (11).

It is on 4 that angled mirrors 3 is installed on main shaft, and main shaft is 4 can be by the relative bearing block 8 coaxial rotations of stepper motor 5 control, also can be its and bearing block 8 is locked by electromagnet 6, and bearing block 8 is fixed with tested numerical control rotating platform 10.

LASER Light Source 7 is fixed in bearing block 8, when measuring, rotates with bearing block 8 and tested numerical control rotating platform 10;

Receiver 9 is installed on the fixed position, and aims at the light beam that LASER Light Source 7 sends, and during the light beam that sends when LASER Light Source 7 is inswept receiver 9, produces a full circle pulse signal;

The signal of control electronic box 11 receiving computers 12, and control step motor 5 and electromagnet 6;

Computer 12 receives laser head 1 through the signal of control electronic box 11 and the full circle pulse signal of receiver 9, and computing also shows measurement result.

Fig. 4 is the measurement mechanism front view of the employing measuring position precision of digital control turntable by using laser angle interferometer that proposes of the present invention, and Fig. 5 is the right cutaway view of Fig. 4.Axle system by two bearings 30, bearing cap () 14, bearing block 8, main shaft 22, terminal pad 21, bearing cap (two) 24, cover 26, cover 27 and trip bolt composition measuring apparatus.Laser angle speculum 3 usefulness screws are connected connecting plate 23 with screw with after connecting plate 23 is connected again with terminal pad 21; Stepper motor 5 usefulness screws are with after motor cabinet 19 is connected; With screw motor cabinet 19 and terminal pad 21 are connected again; The axle head of stepper motor 5 is connected with screw and gear 17, and gear 17 and dish gear 18 engagements that are fixed on screw on the bearing block 8 are when stepper motor 5 rotates; Gear 17 is made main shaft 22 rotations by dish gear 18 counter pushing away; Magnetic receiver 25 is connected with terminal pad 21; Be connected with electromagnet 6 with screw on the magnetic receiver 25; Be connected with screw and bearing block 8 after adhesive disk 16 usefulness screws and packing ring and thin discs 15 are connected, electromagnet 6 contacts with adhesive disk 16 again, sucks adhesive disk 16 during electromagnet 6 energisings; Main shaft 22 can not be rotated, and promptly angled mirrors 3 can be rotated with bearing block 8 synchronously; Cushion cover 13 usefulness screws and bearing block 8 are connected; Mid-game 29 is connected with cushion cover 13; The location cylindrical of mid-game 29 is put into the Kong Zhonghou of tested numerical control rotating platform 10 centres of gyration; Make the centre of gyration of measurement mechanism axle owner axle 22 coaxial with the centre of gyration of tested numerical control rotating platform 10, thus requirement that must be coaxial when guaranteeing 3 rotations of laser angle speculum with numerical control rotating platform; LASER Light Source 7 pack into laser light source(-)holder 33 and be screwed after; With screw laser light source(-)holder 33 and bearing block 8 are connected again; During measurement, LASER Light Source 7 remains energising, and the light beam that light source sends is received by the light source receiver that is installed in bearing 9; Produce all pulse signals of a full circle and send computer 12, thereby accurately confirm the complete cycle that tested numerical control rotating platform 10 turns over; With the screw presser feet 28 that is connected,, make its synchronous rotation on the bearing block 8 so that bearing block 8 is connected with tested numerical control rotating platform 10; Connector assembly 31 usefulness screws are reinforced on terminal pad 21, and the signal of control step motor 5 and electromagnet 6 is introduced thus; Stop screw 32 in the terminal pad 21 is used to limit the rotation of main shaft 22, must remove the restriction to main shaft 22 rotations before measuring; Outer cover 20 usefulness screws are connected with terminal pad 21, with the protection measurement mechanism.

LASER Light Source 7 also can be installed in the optional position of tested numerical control rotating platform 10 rotary table tops.

Measuring process:

If measure m week, the assay intervals Δ, then the detection number of times in weekly is the n=360/ Δ, measuring process is following in the direction of the clock.

(1) with measurement mechanism (by angled mirrors 3, main shaft be 4, bearing block 8, stepper motor 5, electromagnet 6, LASER Light Source 7 etc. constitute) be fixed on the tested numerical control rotating platform 10, tested numerical control rotating platform 10 is coaxial with the gyroaxis of measurement mechanism;

(2) in the fixed position recipient 9 is installed, when making tested numerical control rotating platform 10 rotations, the light beam that LASER Light Source 7 sends can inswept receiver 9;

(3) laser head 1, angle intervention module 2 are installed, rotating spindle is 4, makes the surface of angled mirrors 3 vertical with incoming laser beam, computer 12 zero clearings,

(4) measure beginning, it is 4 that electromagnet 6 unclamps main shaft, and stepper motor 5 control main shafts are 4 to be rotated counterclockwise Δ/2;

(5) electromagnet 6 again with main shaft be 4 with bearing block 8 locked, computer 12 is write down angular readings a (1,1);

(6) tested numerical control rotating platform 10 Δ that turns clockwise, computer 12 is write down angular readings b (1,1);

(7) electromagnet 6 is 4 to unclamp with bearing block 8 with main shaft, is 4 to be rotated counterclockwise Δ by stepper motor 5 control main shafts;

(8) repeat (5)-(7) step n time, computer 12 write down the 1st circle value of taking measurement of an angle a (1, n) and b (1, n), accomplish the 1st and enclose measurement;

(9) in the 1st circle is measured, produce during the inswept light source of light beam receiver 9 that LASER Light Source 7 sends one full circle week pulse signal sampling with respect to this assay intervals starting point a (1, n ₀) angle value c (1,1).

(10) repeat (5)-(9) step m time, computer 12 write down three-dimensional array a (m, n), b (m, n) and c (m, s); Measurement finishes.

(11) the counter-clockwise direction measurement is carried out (4)-(10) as stated above, and just direction of rotation is reverse.

M=1 wherein ... M, n=1 ... N, s=1 ... M-1,

n ₀Assay intervals position for full circle week pulse signal place.

After above-mentioned measurement, computer 12 obtains instantaneous pin, counter-clockwise two groups of three-dimensional array:

A (m, n): at the angle value of the starting point of m week n interval measurement;

B (m, n): at the angle value of the terminating point of m week n interval measurement;

(m, s): in m week s interval, the full circle pulse signal sampling that receiver 9 produces is with respect to this assay intervals starting point a (m, n for c ₀) angle value.

(12) computer carries out data, computing formula:

The measured value y of each assay intervals Δ (m, n):

y(m，n)＝b(m，n)-a(m，n) (1)

Angle and z between all pulse signals of per two adjacent full circle _s:

$z_s=\underset{n_0+1}{\overset{n}{\mathrm{\Σ}}}y(m,n-n_0)+\underset{1}{\overset{n_s}{\mathrm{\Σ}}}y(m+1,n_s-1)+y(m,n_0)-c(m,s)+c(m+1,s)---\left(2\right)$

N wherein _s=1 ... N ₀

Between two adjacent full circle week pulse signals angle and mean value z _s:

$\stackrel{\‾}{z_s}=\frac{\underset{1}{\overset{s}{\mathrm{\Σ}}}{z}_s}{s}---\left(3\right)$

According to wholecircle error closure principle, calculate the angle correct factor beta:

β＝3600×360/z _s (4)

The error amount e of each assay intervals Δ (m, n):

e(m，n)＝y(m，n)×β-Δ (5)

During complete cycle is measured, each assay intervals with respect to the error amount δ that measures starting point (m, n):

$\left\{\begin{array}{c}\mathrm{\δ}(m,n)=e(m,1)\\ \mathrm{\δ}(m,n)=\mathrm{\δ}(m,n-1)+e(m,n)\end{array}\right\}---\left(6\right)$

Computer (12) is according to the regulation of the examination criteria GB-17421.2-2000 of Digit Control Machine Tool; Calculate clockwise, the counter-clockwise every circle complete cycle of tested numerical control rotating platform (10) and measure each assay intervals with respect to the error amount δ (m that measures starting point; N) after, obtain the positioning accuracy and the repetitive positioning accuracy of numerical control rotating platform (10) again by standard code.

Claims (5)

1. the device of measuring position precision of digital control turntable by using laser angle interferometer, laser head (1) and angle intervention module (2) fixed-site, the laser beam that laser head (1) sends is divided into two-way directive angled mirrors (3) respectively through angle intervention module (2); Angled mirrors (3) Returning beam is through angle intervention module (2) directive laser head (1), and its signal send computer (12) again and converts angle value into through control electronic box (11), it is characterized in that main shaft (22) and terminal pad (21) are connected; Main shaft (22) is positioned at the bearing (30) of bearing block (8), and main shaft (22) is concentric with tested numerical control rotating platform, and bearing block (8) is connected with tested numerical control rotating platform; Bearing block is connected with adhesive disk (16), and bearing block is connected with dish gear (18), and electromagnet (6) is connected with terminal pad (21); Electromagnet and adhesive disk (16) are relative, and stepper motor seat (19) is connected with terminal pad (21), and the axle head of stepper motor (5) and gear (17) are connected; Gear (17) and dish gear (18) engagement; Angled mirrors (3) is connected with terminal pad (21), and terminal pad (21) is connected with bearing block (8) through stop screw (32), and LASER Light Source (7) is fixed in bearing block (8); Receiver (9) is installed on the fixed position and aims at LASER Light Source (7); Receiver (9) is connected with computer (12), and computer (12) is connected with control electronic box (11), and control electronic box (11) is connected with electromagnet (6) with stepper motor (5).

2. device according to claim 1; It is characterized in that cushion cover (13) and bearing block (8) are connected; Mid-game (29) is connected with cushion cover (13), the location cylindrical of mid-game (29) is arranged in the hole of tested numerical control rotating platform (10) centre of gyration, main shaft (22) is coaxial with this hole.

3. device according to claim 1 is characterized in that LASER Light Source (7) can be installed in the optional position of tested numerical control rotating platform (10) rotary table top.

4. the method for measurement device position precision of digital control turntable by using according to claim 1; Its measuring process is following: according to the examination criteria GB-17421.2-2000 of Digit Control Machine Tool regulation, to numerical control revolving table position accuracy detection need be suitable in complete cycle according to certain interval, counterclockwise measure several weeks;

If measure m week, the assay intervals Δ, then the detection number of times in weekly is a n=360 °/Δ, measuring process is following in the direction of the clock:

(1) will be fixed on the tested numerical control rotating platform (10) by the measurement mechanism that angled mirrors (3), main shaft system (4), bearing block (8), stepper motor (5), electromagnet (6), LASER Light Source (7) constitute, make tested numerical control rotating platform (10) coaxial with the main shaft of measurement mechanism;

(2) in the fixed position receiver (9) is installed, when making tested numerical control rotating platform (10) rotation, the light beam that LASER Light Source (7) sends can inswept receiver (9);

(3) laser head (1), angle intervention module (2) are installed, rotating spindle system (4) makes the surface of angled mirrors (3) vertical with incoming laser beam, computer (12) zero clearing;

(4) measure beginning, electromagnet (6) unclamps main shaft system (4), and stepper motor (5) control main shaft system (4) is rotated counterclockwise Δ/2;

(5) electromagnet (6) is locked with bearing block (8) with main shaft system (4) again, and computer (12) is write down angular readings a (1,1);

(6) tested numerical control rotating platform (10) Δ that turns clockwise, computer (12) is write down angular readings b (1,1);

(7) electromagnet (6) unclamps main shaft system (4), is rotated counterclockwise Δ by stepper motor (5) control main shaft system (4);

(8) repeating step (5)-(7) are n time, computer (12) write down the 1st circle value of taking measurement of an angle a (1, n) with b (1, n), accomplish the 1st and enclose measurement;

(9) in the 1st circle is measured, produce during the inswept receiver of light beam (9) that LASER Light Source (7) sends one full circle week pulse signal sampling with respect to assay intervals starting point a (1, n ₀) angle value c (1,1);

(10) repeating step (5)-(9) are m time, computer (12) write down three-dimensional array a (m, n), b (m, n) and c (m, s); The clockwise direction measurement finishes;

(11) counter-clockwise direction is measured and is undertaken by above-mentioned steps (4)-(10), and just direction of rotation is reverse;

M=1 wherein ... M, n=1 ... 360 °/Δ, s=1 ... M-1;

n ₀Assay intervals position for full circle week pulse signal place;

After above-mentioned measurement, computer (12) obtains clockwise, counter-clockwise two groups of three-dimensional array:

A (m, n): the angle value of measuring starting point in m week n assay intervals;

B (m, n): the angle value of measuring terminating point in m week n assay intervals;

(m, s): in m week s assay intervals, all pulse signal samplings of the full circle that receiver (9) produces are with respect to this assay intervals starting point a (m, n for c ₀) angle value;

(12) computer data is handled.

5. according to the said method of claim 4, its computer data treatment step is following:

The measured value y of each assay intervals Δ (m, n):

y(m，n)＝b(m，n)-a(m，n) (1)

Angle and z between all pulse signals of per two adjacent full circle _s:

$z_s=\underset{n_0+1}{\overset{n}{\mathrm{\Σ}}}y(m,n-n_0)+\underset{1}{\overset{n_s}{\mathrm{\Σ}}}y(m+1,n_s-1)+y(m,n_0)-c(m,s)+c(m+1,s)---\left(2\right)$

N wherein _s=1 ... N ₀,

Between two adjacent full circle week pulse signals angle and mean value

$\stackrel{\‾}{z_s}=\frac{\underset{1}{\overset{s}{\mathrm{\Σ}}}{z}_s}{s}---\left(3\right)$

According to wholecircle error closure principle, calculate the angle correct factor beta:

$\mathrm{\β}=3600\×360/\stackrel{\‾}{z_s}---\left(4\right)$

The error amount e of each assay intervals Δ (m, n):

e(m，n)＝y(m，n)×β-Δ (5)

During complete cycle is measured, each assay intervals with respect to the error amount δ that measures starting point (m, n):

$\left\{\begin{array}{c}\mathrm{\δ}(m,n)=e(m,1)\\ \mathrm{\δ}(m,n)=\mathrm{\δ}(m,n-1)+e(m,n)\end{array}\right\}---\left(6\right)$

Computer (12) is according to the regulation of the examination criteria GB-17421.2-2000 of Digit Control Machine Tool; Calculate clockwise, the counter-clockwise every circle complete cycle of tested numerical control rotating platform (10) and measure each assay intervals with respect to the error amount δ (m that measures starting point; N) after, obtain the positioning accuracy and the repetitive positioning accuracy of numerical control rotating platform (10) again by standard code.

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