CN105136076B - Large-stroke linkage mechanism two-dimensional plane roundness error calibration method - Google Patents

Abstract

A large-stroke linkage mechanism two-dimensional plane roundness error calibration method relates to work piece processing two-dimensional plane error. The method comprises the following steps: the overall linkage area of a mechanism is divided into multiple local areas, every two adjacent local areas overlap, the bar length of a ball bar is selected, and linkage error detection is carried out in all the local areas to obtain multiple pieces of local linkage error information based on the center of each local area; error separation is carried out on the local linkage error information based on the center of each local area to obtain the local motion error of two linkage linear axes in each detection area and further obtain the actual coordinates of the end of the ball bar at each motion position; an overall linkage trajectory based on all the local areas is spliced according to the fact that adjacent detection areas have the same error separation information in the overlapping portion; and the center of the whole detection area is set as a common base point, the radial error of each point on the overall linkage trajectory to the base point is calculated, and the overall motion error of each linear axis of motion is separated based on the least squares algorithm for mechanism linkage error compensation.

Description

Big stroke link gear two dimensional surface deviation from circular from scaling method

Technical field

The present invention relates to work processing two dimensional surface error, especially relate to a kind of big stroke link gear two dimensional surface circle Degree error calibrating method.

Background technology

Due to manufacturing the presence with rigging error, unavoidably there is certain error in mechanism itself.And the essence of mechanism itself Degree especially geometric error often greatly affects processing and the detection of workpiece.Over nearly 10 years, with manufacturing quick Exhibition, the size of part is increasing, and structure becomes increasingly complex, and geometric accuracy improves constantly, therefore to part processing and testing machine The required precision of structure also more and more higher.Correct error identification and error compensation, are to improve having of mechanism's processing or accuracy of detection Effect approach.

Typically conventional error identification method has two kinds: direct Detection Method and the indirect method of measurement, its typical equipments is respectively Laser interferometer and ball bar.Detected compared to using laser interferometer, ball bar have equipment cost cheap, operation letter The advantages of list, measurement efficiency are high, but simultaneously, its detection range is limited by club radius.Many scholars are to ball bar in lathe Error identification is conducted in-depth research with the application in compensation.(s.ibaraki, the w.knapp.indirect such as w.t.lei measurement of volumetric accuracy for three-axis and five-axis machine Tools:a review, j.int.j.of automation technology, 2012,6 (22): 110-124) utilize ball bar The be possible to movement combination of the linear axis to five-axis machine tool and rotary shaft is studied, so that it is determined that linear axes and rotary shaft Between dynamic differential.(w.t.lei, i.m.paung, the chen-chiyu.total ball bar such as masaomi tsutsumi dynamic tests for five-axis cnc machine tools,j.international journal of Machine tools＆manufacture, 2009,49:488-499) can be inclined to carrying by two kinds of different modes of ball bar 5 axle machining centers of rotary table carry out the demarcation of geometrical deviation, and by cutting the method validation scaling method of the frustum of a cone Effectiveness.(masaomi tsutsumi, the shintarotone etc.enhancement of geometric such as zhang, y accuracy of five-axis machining centers based on identification and compensation of geometric deviations,j.international journal of machine Tools＆manufacture, 2013,68:11-20) using ball bar, geometric error is carried out to five-axle number control machine tool turntable, lead to Cross Different Plane two kinds of ball bar path decomposings are cutting edge aligned and angular errors, and confirm that the method can effectively identify that turntable causes Geometric error.(y.y.zhang, j.g, the k.zhang.geometric error measurement and such as chen, jx compensation for the rotary table of five-axis machine tool with double ballbar,j.international journal of advanced manufacturing technology,2013,65 (1-4) ball bar: 275-281) is adopted to detect that the geometric error of rotation platform, it is proposed that 2 step error identification method, proposes simultaneously A kind of method correcting ball bar error in mounting position, and carry out experimental verification.But, current research is concentrated mainly on band rotation Turn the five-axle number control machine tool field of platform, the research to big stroke link gear two dimensional surface deviation from circular from is less.Although it is existing Research have certain reference and directive significance to the identification of big stroke link gear two dimensional surface deviation from circular from compensating, but Big stroke link gear is different from the rotation platform of Digit Control Machine Tool after all.Therefore, research a kind of based on ball bar loop test Stitching algorithm is significant with compensation with the identification realizing big stroke link gear two dimensional surface deviation from circular from.

Content of the invention

Present invention aims to measurement range during error calibration is carried out to big stroke link gear using ball bar By the long restricted problem of bar, provide a kind of high accuracy, the big stroke link gear two dimensional surface deviation from circular from scaling method of low cost.

The present invention comprises the following steps:

1) stroke according to link gear, the suitable ball bar bar of selection is long, and carries out region division, and mechanism is integrally joined Dynamic region division becomes a n regional area, n >=2, has lap between every adjacent part areas；

2) mobile ball bar magnetic bases are to regional area center o each in mechanism's xoy plane₁(x₀₁,y₀₁), o₂(x₀₂, y₀₂) ..., o_n(x_0n,y_0n), using ball bar, be circulated test in each regional area respectively, obtain multiple based on each local The local linkage control information δ r in the center of circle_1,i,δr_2,j,…；

3) error separate is carried out to the linkage information based on ball bar loop test by method of least square, obtain each local On region, each movement position is with respect to local motion control information (the δ x in the respective center of circle_1,i,δy_1,i),(δx_2,j,δ y_2,j) ..., and then obtain in each regional area ball bar end in the actual coordinate p ' of each movement position₁(x′_1,i,y′_1,i),p′₂ (x′_2,j,y′_2,j),…；

4) in lap, there is identical separation control information according to adjacent part areas, all regional areas are carried The linkage track of linkage control information is overlapped, and first, solves the intersection point between adjacent part areas, secondly with intersection point as boundary, Obtain the union in adjacent linkage region successively, be finally spliced into the Coupled motion track based on each local；

5) set Coupled motion regional center as public basic point o (x₀,y₀), will splice and be based on gained Coupled motion track The linkage control information in the local center of circle, is converted by corresponding, changes into the radial direction of each point p to basic point o on Coupled motion track by mistake Difference δ l, this error is link gear Coupled motion control information；

6) it is based on least-squares algorithm, error separate is carried out to big stroke link gear Coupled motion error, that is, obtain each Linear motion axis mass motion control information, carries out, further with this error information, the error compensation that links, that is, to link gear Can achieve the demarcation of big stroke link gear two dimensional surface deviation from circular from.

The linkage control information technology in local based on ball bar loop test for the present invention, by stitching algorithm and error separate Calculate, obtain each universal driving shaft mass motion control information, finally realize the big stroke link gear linkage convenient compensation of error.The party Method enables the efficient demarcation to big stroke link gear two dimensional surface deviation from circular from, and the method has the spy of low cost simultaneously Point.

The present invention is detected to the linkage error in multiple regions in big stroke link gear xoy plane using ball bar, Obtain the kinematic error information based on each regional area center, according to the lap separation error letter of adjacent local detection area Cease consistent principle, by stitching algorithm, obtain mechanism's Coupled motion track.Set mechanism Coupled motion central point is common base Point o, the linkage control information based on the respective center of circle on splicing gained Coupled motion track changes into each on Coupled motion track The radial error δ l of point p to basic point o, with obtaining means Coupled motion control information.It is finally based on least square to Coupled motion Control information carries out error separate, obtains each linear motion axis mass motion control information, finally realizes mechanism's linkage error and mends Repay.

Brief description

Fig. 1 is the ball bar subregion detection splicing principle of the embodiment of the present invention

Fig. 2 is the ball bar local detection result of the embodiment of the present invention

Fig. 3 is the ball bar local detection error map of the embodiment of the present invention

Fig. 4 is three testing results of ball bar after the error calibration of the embodiment of the present invention

Fig. 5 is three detection errors distributions of ball bar after the error calibration of the embodiment of the present invention

Specific embodiment

Below in conjunction with the accompanying drawings technical scheme is further elaborated.

Big stroke link gear 500mm × 500mm scope is carried out with two dimensional surface linkage error calibration, wherein x-axis stroke For 100～600mm, y-axis stroke is -600～-100mm.Magnetic in xoy plane monitoring-network, on one end and workbench for the ball bar Ball seat contacts, and the other end is contacted with the magnetic ball seat on machine tool chief axis.

It is 500mm × 500mm according to mechanism's Coupled motion region, a length of 150mm of selected ball bar bar, as shown in figure 1, will Overall region is divided into 4 regional areas, each local detection area center o₁(x₀₁,y₀₁),o₂(x₀₂,y₀₂),o₃(x₀₃, y₀₃),o₄(x₀₄,y₀₄) it is respectively (250, -250), (450, -250), (250, -450), (450, -450), mobile ball bar magnetic Property base to above 4 positions, be circulated test using the ball bar of a length of 150mm of bar respectively, obtain 4 be based on each justify The local linkage control information δ r of the heart_1,i,δr_2,j,δr_3,k,δr_4,l, as shown in Fig. 2 its error distribution situation such as Fig. 3 institute Show, now three coordinate measuring machine maximum deviation from circular from the range of 500mm × 500mm is 55 μm.

Using method of least square to δ r_1,i,δr_2,j,δr_3,k,δr_4,lCarry out separating, each motion bit on each regional area Put local motion control information (the δ x with respect to the respective center of circle_1,i,δy_1,i),(δx_2,j,δy_2,j),(δx_3,k,δy_3,k), (δx_4,l,δy_4,l), and then obtain in 4 regional areas ball bar end in the actual coordinate p ' of each movement position₁(x′_1,i, y′_1,i),p′₂(x′_2,j,y′_2,j),p′₃(x′_3,k,y′_3,k),p′₄(x′_4,l,y′_4,l), remember θ_mFor o_mp_mWith x-axis angle, concrete formula For

Set from each local detection area center, adjacent local detection area is in the overlap length in x, y direction It is 100mm.As shown in figure 1, the outside intersection point between adjacent local detection area is a (x_a,y_a),b(x_b,y_b),c(x_c,y_c),d (x_d,y_d), identical separation control information is had in lap according to adjacent detection area, connection is carried to all regional areas The linkage track of dynamic control information is overlapped, and obtains final productWith, complete 500mm × 500mm scope and be based on The splicing of the Coupled motion track of each local.Note r=150mm, θ_mFor o_mp_mAngle and between x-axis, then this Coupled motion track Theoretical coordinate p (x, y) of upper point and actual coordinate p ' (x ', y ') are represented by:

$\begin{array}{c}x=\left\{\begin{array}{cc}r\cos {\mathrm{\θ}}_1+x_{01}& x\≤x_b\∩y\≤y_c\\ r\cos {\mathrm{\θ}}_2+x_{02}& x\&greaterequal;x_b\∩y\≤y_d\\ r\cos {\mathrm{\θ}}_3+x_{03}& x\≤x_a\∩y\&greaterequal;y_c\\ r\cos {\mathrm{\θ}}_4+x_{04}& x\&greaterequal;x_a\∩y\&greaterequal;y_d\end{array}\right.\\ y=\left\{\begin{array}{cc}r\sin {\mathrm{\θ}}_1+y_{01}& x\≤x_b\∩y\≤y_c\\ r\sin {\mathrm{\θ}}_2+y_{02}& x\&greaterequal;x_b\∩y\≤y_d\\ {r\sin \mathrm{\θ}}_3+y_{03}& x\≤x_a\∩y\&greaterequal;y_c\\ r\sin {\mathrm{\θ}}_4+y_{04}& x\&greaterequal;x_a\∩y\&greaterequal;y_d\end{array}\right.\end{array}---\left(3\right)$

As basic point coordinate o (x₀,y₀) for (350, -350) when, will splice on gained Coupled motion track based on the local center of circle Linkage control information pass through corresponding convert, change into the radial error δ l of each point p to basic point o on profile, this error is connection Motivation structure Coupled motion control information, its concrete transformation for mula is

$\mathrm{\δl}=\sqrt{{(x^{\′}-x_0)}^2+{(y^{\′}-y_0)}^2}-\sqrt{{(x-x_0)}^2+{(y-y_0)}^2}---\left(5\right)$

Based on least-squares algorithm, error separate is carried out to big stroke link gear Coupled motion error, obtain each straight line fortune Moving axis mass motion control information, and carry out error compensation.

In the present embodiment, after each linear axis error compensation, mobile magnetic ball seat is to (350, -350), a length of using bar The ball bar of 250mm carries out repeated detection to 500mm × 500mm Coupled motion error, and testing result is as shown in figure 4, its error Error distribution situation after compensation as shown in figure 5, now, three coordinate measuring machine 500mm × 500mm scope maximum deviation from circular from by Before compensation 55 μm are reduced to 11 μm, therefore this error calibrating method is effective and feasible.

The present invention relates to big stroke link gear two dimensional surface deviation from circular from detection is realized based on ball bar loop test Method.First, mechanism's Coupled motion region division is become multiple regional areas, between every adjacent part areas, have certain length Lap, it is long to choose suitable ball bar bar, carries out, in each regional area, the error-detecting that links respectively, obtain multiple based on each The local linkage control information amount at regional area center.Secondly the local linkage control information based on each regional area center is entered Row error separate, obtains the local motion error in each detection zone for the two linkage linear axis, then obtains ball bar end each The actual coordinate of movement position.Again, identical separation control information is had in lap according to adjacent detection area, splicing Go out the Coupled motion track based on each local.Finally, set whole detection regional center as public basic point, calculate Coupled motion On track, each point to the radial error of this basic point, that is, obtains Coupled motion control information, and is based on least-squares algorithm, final point Separate out each linear motion axis mass motion error, for mechanism's linkage error compensation.The method can achieve to big stroke gear Efficient, the inexpensive deviation from circular from of structure is demarcated.

Claims (1)

1. big stroke link gear two dimensional surface deviation from circular from scaling method is it is characterised in that comprise the following steps:

1) stroke according to link gear, the suitable ball bar bar of selection is long, and carries out region division, by Coupled motion area of mechanism Domain is divided into n regional area, n >=2, has lap between every adjacent part areas；

2) mobile ball bar magnetic bases are to regional area center o each in mechanism's xoy plane₁(x₀₁,y₀₁), o₂(x₀₂, y₀₂) ..., o_n(x_0n,y_0n), using ball bar, be circulated test in each regional area respectively, obtain multiple based on each local The local linkage control information δ r in the center of circle_1,i,δr_2,j,…；

3) error separate is carried out to the linkage information based on ball bar loop test by method of least square, obtain each regional area Upper each movement position is with respect to local motion control information (the δ x in the respective center of circle_1,i,δy_1,i),(δx_2,j,δy_2,j) ..., enter And obtain in each regional area ball bar end in the actual coordinate p ' of each movement position₁(x′_1,i,y′_1,i),p′₂(x′_2,j,y ′_2,j),…；

4) in lap, there is identical separation control information according to adjacent part areas, linkage is carried to all regional areas The linkage track of control information is overlapped, and first, solves the intersection point between adjacent part areas, secondly with intersection point as boundary, successively Obtain the union in adjacent linkage region, be finally spliced into the Coupled motion track based on each local；

5) set Coupled motion regional center as public basic point o (x₀,y₀), will splice and local will be based on gained Coupled motion track The linkage control information in the center of circle, is converted by corresponding, changes on Coupled motion track each point to the radial error δ l of basic point, This error is link gear Coupled motion control information；

6) it is based on least-squares algorithm, error separate is carried out to big stroke link gear Coupled motion error, that is, obtains each straight line Kinematic axiss mass motion control information, carries out, further with this error information, the error compensation that links to link gear, you can real The now demarcation of big stroke link gear two dimensional surface deviation from circular from.