Embodiment
As shown in Figure 1, contact aspheric surface verifying attachment of the present invention comprises computing machine 1 and laser tracker 2; Described laser tracker 2 and computing machine 1 are connected by data line.
Laser tracker 2 is a kind of high precision, jumbo portable three coordinate measurment instruments, and this laser tracker uses two rotary angle encoders and a laser distance measuring system, with the position of tracking and measurement target drone ball 3.Target ball 3 is made up of hollow corner cube mirror, and this catoptron accurately is fixed in the processing spheroid.Outer surface of spheroid is to the distance at center known (being radius of sphericity), and the laser tracker Survey Software utilizes radius of sphericity to measure skew or compensating measure.Laser tracker emission also receives the red He-Ne Lasers that returns from the target ball, and two rotary angle encoders and Range Measurement System feedack that the direction of laser tracker mechanical axis can receive according to the location sensitive detector of its inside are constantly adjusted.Laser tracker is determined the coordinate of target by measuring two angles and distance.These angles are measured by the scrambler that is installed on angle, summit axle and the azimuth axis.Radial distance is to be measured by fringe count micrometer or a kind of phase deviation absolute distance measurement system (XtremeADM).Laser tracker generally is used for the relative position relation between the Measuring Object, and can the Direct Test plane and the face shape of sphere object, but but can not realize Direct Test for the face shape of non-spherical element.
As shown in Figure 2, the Survey Software of described computing machine 1 comprises device 11, the coordinate transformation device 12 of storing aspheric surface cad model to be measured, finds the solution the device 13 of position coordinates and finds the solution the device 14 that aspheric surface to be measured distributes.
Described coordinate transformation device 12 is searched aspheric cad model to be measured, extracts the unique point p that measures with laser tracker 2
1(x
1, y
1, z
1), p
2(x
2, y
2, z
2) and p
3(x
3, y
3, z
3) the position coordinates P of unique point on the corresponding cad model
1(X
1, Y
1, Z
1), P
2(X
2, Y
2, Z
2) and P
3(X
3, Y
3, Z
3), as shown in Figure 3; By the Nonlinear System of Equations of solution by iterative method formula (1) and formula (5) simultaneous, the translational movement d of coordinate system on x direction, y direction, z direction that to obtain aspheric physical coordinates to be measured be relative cad model
x, d
yAnd d
zAnd the aspheric physical coordinates to be measured coordinate system that is relative cad model is around angle of rotation tolerance α, the β and the γ of x axle, y axle, z axle, and then two coordinate systems are unified to the same coordinate system;
(x wherein
1, y
1, z
1, 1) and be p
1(x
1, y
1, z
1) the coordinate row matrix of point in aspheric physical coordinates to be measured is, (X
1, Y
1, Z
1, 1) be and p
1(x
1, y
1, z
1) put corresponding P
1(X
1, Y
1, Z
1) the coordinate row matrix of point in the cad model coordinate system; (x
2, y
2, z
2, 1) and be p
2(x
2, y
2, z
2) the coordinate row matrix of point in aspheric physical coordinates to be measured is, (X
2, Y
2, Z
2, 1) be and p
2(x
2, y
2, z
2) put corresponding P
2(X
2, Y
2, Z
2) the coordinate row matrix of point in the cad model coordinate system; (x
3, y
3, z
3, 1) and be p
3(x
3, y
3, z
3) the coordinate row matrix of point in aspheric physical coordinates to be measured is, (X
3, Y
3, Z
3, 1) be and p
3(x
3, y
3, z
3) put corresponding P
3(X
3, Y
3, Z
3) the coordinate row matrix of point in the cad model coordinate system; d
x, d
yAnd d
zBeing respectively aspheric physical coordinates to be measured is the translational movement of relative cad model coordinate system on x direction, y direction, z direction, and it is the angle of rotation tolerance of relative cad model coordinate system around x axle, y axle, z axle that α, β are respectively aspheric physical coordinates to be measured with γ.
Described unique point p
1(x
1, y
1, z
1), p
2(x
2, y
2, z
2) and p
3(x
3, y
3, z
3) be the lightweight circular hole at aspheric surface to be measured side or back, the center of circle of taper hole or tri-angle-holed center.Can measure the coordinate of any three points on circular hole or the taper hole edge by elder generation, and then calculate its central coordinate of circle; The coordinate at tri-angle-holed center can utilize the coordinate on an Atria summit by calculating.
Described device 13 of finding the solution position coordinates utilizes the position coordinates of multiple spot on the aspheric surface that measures, and calculates by cubic spline interpolation or Newton interpolation method and finds the solution the position coordinates that obtains each point on the aspheric surface.
As shown in Figure 4, the step of utilizing the present invention that aspheric surface is tested is as follows:
1) at first, sets up aspheric cad model to be measured, and this cad model is imported in the Survey Software of computing machine 1;
2) utilize laser tracker 2 to measure three unique point p at aspheric surface to be measured side or back
1, p
2And p
3Position coordinates p
1(x
1, y
1, z
1), p
2(x
2, y
2, z
2) and p
3(x
3, y
3, z
3);
3) search aspheric cad model, extract and the unique point p that measures
1(x
1, y
1, z
1), p
2(x
2, y
2, z
2) and p
3(x
3, y
3, z
3) the position coordinates P of unique point on the corresponding CAD digital-to-analogue
1(X
1, Y
1, Z
1), P
2(X
2, Y
2, Z
2) and P
3(X
3, Y
3, Z
3);
4), can find the solution and obtain two translational movement and rotation amounts between the coordinate system, thereby make that aspheric surface to be measured physical coordinates system at this moment is consistent with the coordinate system of cad model by coordinate transform;
The specific algorithm step is as follows:
Set p
1The coordinate representation of point in aspheric physical coordinates to be measured is is row matrix (x
1, y
1, z
1, 1), with p
1Corresponding P
1The coordinate representation of point in the cad model coordinate system is row matrix (X
1, Y
1, Z
1, 1); Suppose that the translational movement of coordinate system on x direction, y direction, z direction that aspheric physical coordinates to be measured is relative cad model is respectively d
x, d
yAnd d
zThe coordinate system that aspheric physical coordinates to be measured is relative cad model is respectively α, β and γ around the angle of rotation tolerance of x axle, y axle, z axle, then according to the coordinate transform theory, the position coordinates of character pair has following relation on feature locations coordinate that aspheric physical coordinates to be measured is fastened and the cad model:
Wherein V is two transformation matrixs between the coordinate system, and it is the product between translation transformation matrix T and the rotational transform matrix R, that is:
V=T·R (2)
T wherein
x, T
yAnd T
zBe respectively the translation matrix of two row matrixs on x direction, y direction and z direction.
R wherein
x, R
yAnd R
zBe respectively the rotation matrix of two row matrixs on x direction, y direction and z direction.
Then can being derived by (3)-(4), to obtain two transformation matrix V between the coordinate system be formula (5),
Because three unique points coordinate figure in two coordinate systems respectively are known, by the Nonlinear System of Equations of solution by iterative method formula (1) and formula (5) simultaneous, the translational movement d of coordinate system on x direction, y direction, z direction that can to obtain aspheric physical coordinates to be measured be relative cad model
x, d
yAnd d
zAnd the aspheric physical coordinates to be measured coordinate system that is relative cad model is around angle of rotation tolerance α, the β and the γ of x axle, y axle, z axle, thereby two coordinate systems can be come together;
5) after two coordinate system unanimities, utilize laser tracker 1 to measure under unified coordinate system the position coordinates of multiple spot on the aspheric surface to be measured;
6) utilize the position coordinates of multiple spot on the aspheric surface to be measured measure, calculate by cubic spline interpolation and find the solution the position coordinates that obtains each point on the aspheric surface to be measured;
7) analysis and solution obtains under the unified coordinate system on the aspheric surface to be measured the deviation of each point coordinate figure on the coordinate figure of each point and corresponding cad model, and deviation data is carried out match, is aspheric shape to be measured and distributes.