Summary of the invention
The technical matters that solves
For solving the problem that prior art exists, the present invention proposes a kind of cutter shaft swing five-coordinate numerally controlled machine tool pendulum length assay method, be under the different angles coordinate figure of reference point in lathe coordinate system (MCS) on the axis of swing by reading lathe turning axle A; And in conjunction with the geometric relationship of five-axis linkage machine tools each essential condition change in location in motion process, calculate the actual pendulum length of five-coordinate numerally controlled machine tool.
Technical scheme
Technical scheme of the present invention is:
Described a kind of cutter shaft swing five-coordinate numerally controlled machine tool pendulum length assay method is characterized in that: adopt following steps:
Step 1: select n different lathe A axle pendulum angle θ
_{i}, i=1,2 ..., n, and θ
_{i}∈ (0 °, 90) °; Described lathe A axle pendulum angle refers to that machine tool chief axis is around the pendulum angle of lathe coordinate system X-axis;
Step 2: the measured value of determining variable quantity:
Standard ball is clamped on the handle of a knife, and the ball centre of sphere that maintains the standard is put relative platen reference point and is maintained static, and measuring lathe A axle pendulum angle is 0 ° and θ
_{i}, i=1,2 ..., during n, standard ball centre of sphere coordinate figure on Y, Z two direction of principal axis in lathe coordinate system; Calculating lathe A axle pendulum angle respectively is θ
_{i}, i=1,2 ..., the coordinate figure of the standard ball centre of sphere on lathe coordinate system Y, Z two direction of principal axis during n, the variable quantity measured value of the coordinate figure of the standard ball centre of sphere on lathe coordinate system Y, Z two direction of principal axis when being 0 ° with lathe A axle pendulum angle
With
I=1,2 ..., n;
Step 3: the calculated value of determining variable quantity:
According to formula:
Determine that lathe A axle pendulum angle is θ
_{i}, i=1,2 ..., the coordinate figure of the standard ball centre of sphere on lathe coordinate system Y, Z two direction of principal axis during n, the variable quantity calculated value of the coordinate figure of the standard ball centre of sphere on lathe coordinate system Y, Z two direction of principal axis when being 0 ° with lathe A axle pendulum angle
With
Wherein
$L=\sqrt{{L}_{y}^{2}+{L}_{z}^{2}},$ $\mathrm{\β}=\mathrm{arctg}\left(\frac{{L}_{y}}{{L}_{z}+H}\right),$ H is machine tool length, L
_{y}And L
_{z}Be the pendulum length parameter, concrete L
_{y}For main shaft gyration center line on the lathe coordinate system Z-direction to the distance of main shaft gyration axis, L
_{z}For shank end face on the lathe coordinate system Y direction to the distance of main shaft gyration axis;
Step 4: determine pendulum length parameter iteration initial value:
Be axially perpendicular under the state of worktable upper surface at five coordinate machine tool chief axis, the cutter end face contacts with the worktable reference point, and machine tool numerical control system shows that the reading of Z direction is Z
_{1}, cutter Y-direction cylinder contacts with the worktable reference point, and machine tool numerical control system shows that the reading of Y-direction is Y
_{1}In under the state of worktable upper surface, the cutter cylinder contacts with the worktable reference point at five coordinate machine tool chief axis axially parallels, and machine tool numerical control system shows that the reading of Z direction is Z
_{2}The cutter end face contacts with the worktable reference point, and machine tool numerical control system shows that the reading of Y-direction is Y
_{2}, obtain pendulum length parameter iteration initial value L
_{Z0}With L
_{Y0}For:
${L}_{Z0}=\frac{1}{2}({Z}_{0}+{Y}_{0}),$
${L}_{y0}=\frac{1}{2}({Z}_{0}-{Y}_{0})$
Z wherein
_{0}=| (Z
_{1}-H)-(Z
_{2}-R) |, Y
_{0}=| (Y
_{1}-R)-(Y
_{2}-H) |, R is the machine tool radius;
Step 5: the pendulum length parameter iteration is optimized:
The pendulum length parameter iteration initial value that obtains with step 4 is the iteration codomain center of circle, with the radius of machine tool chief axis assembly accumulation error as the iteration codomain, with machining precision 1/10th as iteration step length, under corresponding pendulum length parameter, n group variable quantity calculated value
With
With n group variable quantity calculated value
With
The quadratic sum of corresponding deviation obtains one group of pendulum length parameter of judging quota value minimum for passing judgment on optimum pendulum length parameter index after the traversal iteration codomain.
Beneficial effect
A kind of cutter shaft swing five-coordinate numerally controlled machine tool pendulum length assay method that the present invention proposes shows that by cutter shaft digital control system under different pendulum angles relatively the variation (measured value) of Z axle and Y-axis coordinate figure measures with the variation (calculated value) that calculates by actual pendulum length and cutter shaft pendulum angle and determine five number of coordinates control milling machine pendulum lengths.This method can obviously improve machining precision than general 5-shaft linkage numerical control lathe pendulum length algorithm and detection method.
Embodiment
Below in conjunction with specific embodiment the present invention is described:
By the geometric position variation relation of physical construction in the lathe machine motion process, accurately determine the swing axial length of 5-shaft linkage numerical control lathe in the present embodiment, can reach the arbitrary accuracy requirement of regulation.This method can judge easily whether the pendulum length parameter satisfies requirement on machining accuracy simultaneously.
The 5-shaft linkage numerical control lathe has shifting axle X, Y, Z and turning axle A, C, and worktable rotates to be the C axle around the Z axle; Main shaft is the A axle around the X-axis swing.Keep tool length (being called for short the long H of cutter) and cutter heart point (or centre of sphere point) invariant position, in A axle hunting range (0 °～90 °), get n non-0 ° and non-90 ° angle, each non-0 ° and non-90 ° corresponding standard ball centre of sphere of angle be when coordinate figure is rocked to 0 ° with respect to the A axle on Y, Z two direction of principal axis, and the variable quantity of coordinate figure is designated as Δ Y, Δ Z on each non-0 ° and the non-90 ° of corresponding standard ball centre of sphere of angle Y, Z two direction of principal axis.
Above-mentioned variable quantity can obtain by two kinds of methods:
Method one: at first, read the lathe display panel when the A axle swings to except 0 ° and 90 ° arbitrarily angle, the coordinate figure of Y, Z two direction of principal axis; Corresponding coordinate figure asks poor when being rocked to 0 ° with the A axle again.Method two: ask for by the geometric relationship that the machine tool mechanical structure motion is followed.What method one drew is measured value; What method two drew is calculated value.If when calculating is asked for, the pendulum length of employing equates with actual value or is very approaching that then measured value and calculated value should be in very little error ranges.Present embodiment principle is accordingly measured pendulum length.Ignoring under the situation of measuring error, in the machine tool mechanical structure actual motion process, the geometric relationship that A gets the interior pendulum length of [0 °, 90 °-β] scope and machine coordinate values variation satisfies following identical relation:
ΔZ＝L
_{z}+H-L·sin(90°-θ-β)
ΔY＝L·cos(90°-θ-β)-L
_{Y}
Wherein
The measured value of coordinate figure variable quantity on Z axle, Y direction when formula equal sign left end is rocked to 0 ° for coordinate figure on the A axle the is rocked to arbitrarily angled back Z-direction with respect to the A axle; And the result of calculation of right of formula correspondence calculated value of coordinate figure variable quantity on Z axle, the Y direction when coordinate figure is rocked to 0 ° with respect to the A axle on the A axle is rocked to arbitrarily angled back Z axle, the Y direction.
In theory, the centre of gyration line of main shaft should be crossed main shaft gyration axle axle.But the mismachining tolerance when making owing to lathe often causes the center line of machine tool chief axis apart from the main shaft gyration axis certain distance to be arranged.Therefore, use the main shaft gyration center line on the distance (being defined as Lz) of main shaft gyration axis and the Z-direction of shank end face on the Y direction to describe pendulum length to the distance (being defined as Ly) of main shaft gyration axis, these two distance values are called as the pendulum length parameter.All be provided with the both direction parameter such as advanced digital control systems such as SIEMENS840D at pendulum length, to improve machine finish.
Concrete steps in the present embodiment are:
Step 1: select n different lathe A axle pendulum angle θ
_{i}, i=1,2 ..., n, and θ
_{i}∈ (0 °, 90) °; Described lathe A axle pendulum angle refers to that machine tool chief axis is around the pendulum angle of lathe coordinate system X-axis; Get θ in the present embodiment
_{i}=10 °, 25 °, 40 °, 55 °, 70 °.
Step 2: the measured value of determining variable quantity:
Standard ball is clamped in (error is less than 0.005 ㎜) on the handle of a knife, and the ball centre of sphere that maintains the standard is put relative platen reference point and is maintained static, and measuring lathe A axle pendulum angle is 0 ° and θ
_{i}, i=1,2 ..., during n, standard ball centre of sphere coordinate figure on Y, Z two direction of principal axis in lathe coordinate system; Calculating lathe A axle pendulum angle respectively is θ
_{i}, i=1,2 ..., the coordinate figure of the standard ball centre of sphere on lathe coordinate system Y, Z two direction of principal axis during n, the variable quantity measured value of the coordinate figure of the standard ball centre of sphere on lathe coordinate system Y, Z two direction of principal axis when being 0 ° with lathe A axle pendulum angle
With
I=1,2 ..., n;
A axle pendulum angle θ in the present embodiment
_{i}=10 °, 25 °, 40 °, 55 °, 70 ° is that 0 ° measured value table is as shown in the table with A axle pendulum angle:
The measured value table
Step 3: the calculated value of determining variable quantity:
According to formula:
Determine that lathe A axle pendulum angle is θ
_{i}, i=1,2 ..., the coordinate figure of the standard ball centre of sphere on lathe coordinate system Y, Z two direction of principal axis during n, the variable quantity calculated value of the coordinate figure of the standard ball centre of sphere on lathe coordinate system Y, Z two direction of principal axis when being 0 ° with lathe A axle pendulum angle
With
Wherein
$L=\sqrt{{L}_{y}^{2}+{L}_{z}^{2}},$ $\mathrm{\β}=\mathrm{arctg}\left(\frac{{L}_{y}}{{L}_{z}+H}\right),$ H is machine tool length, L
_{y}And L
_{z}Be the pendulum length parameter, concrete L
_{y}For main shaft gyration center line on the lathe coordinate system Z-direction to the distance of main shaft gyration axis, L
_{z}For shank end face on the lathe coordinate system Y direction to the distance of main shaft gyration axis;
Step 4: determine pendulum length parameter iteration initial value:
Be axially perpendicular under the state of worktable upper surface at five coordinate machine tool chief axis, the cutter end face contacts with the worktable reference point, and machine tool numerical control system shows that the reading of Z direction is Z
_{1}, cutter Y-direction cylinder contacts with the worktable reference point, and machine tool numerical control system shows that the reading of Y-direction is Y
_{1}In under the state of worktable upper surface, the cutter cylinder contacts with the worktable reference point at five coordinate machine tool chief axis axially parallels, and machine tool numerical control system shows that the reading of Z direction is Z
_{2}The cutter end face contacts with the worktable reference point, and machine tool numerical control system shows that the reading of Y-direction is Y
_{2}, obtain pendulum length parameter iteration initial value L
_{Z0}With L
_{Y0}For:
${L}_{Z0}=\frac{1}{2}({Z}_{0}+{Y}_{0}),$
${L}_{y0}=\frac{1}{2}({Z}_{0}-{Y}_{0})$
Z wherein
_{0}=| (Z
_{1}-H)-(Z
_{2}-R) |, Y
_{0}=| (Y
_{1}-R)-(Y
_{2}-H) |, R is the machine tool radius;
Pendulum length parameter iteration initial value is as shown in the table in the present embodiment:
Pendulum length initial parameter value list Wei ㎜
Then in the present embodiment, when the pendulum length parameter is got initial value, A axle pendulum angle θ
_{i}=10 °, 25 °, 40 °, 55 °, 70 ° is that 0 ° calculated value table is as shown in the table with A axle pendulum angle:
Pendulum length initial parameter value check list position ㎜
Step 5: the pendulum length parameter iteration is optimized:
The pendulum length parameter iteration initial value that obtains with step 4 is the iteration codomain center of circle, with the radius of machine tool chief axis assembly accumulation error as the iteration codomain, with machining precision 1/10th as iteration step length, under corresponding pendulum length parameter, n group variable quantity calculated value
With
With n group variable quantity calculated value
With
The quadratic sum of corresponding deviation obtains one group of pendulum length parameter of judging quota value minimum for passing judgment on optimum pendulum length parameter index after the traversal iteration codomain.
Recording used five coordinate lathe iteration radiuses in the present embodiment is 0.03 ㎜, and iteration step length is 0.001 ㎜.Iterative computation is as a result shown in the following table:
Interative computation is Dan Wei ㎜ as a result