A kind of structure parameter optimizing method of contactless R-test measuring instrument
Technical field
The invention belongs to contactless R-test five-axle number control machine tool rotation axis error measure instrument fields, especially a kind of
The structure parameter optimizing method of contactless R-test measuring instrument.
Background technique
With the increase of lathe service life, due to wearing, deforming etc., each component geometry precision of lathe is reduced, and makes
The decline of its machining accuracy.The error of accurate measurement lathe point of a knife point is the key that carry out error compensation to improve its machining accuracy,
And to the measurement of the geometric error of lathe rotation axis, there has been no dedicated fine measuring instrument and specifications, generally use laser interference
The problems such as instrument, ball bar etc. are measured indirectly, and low, measurement accuracy that there are measurement efficiencies is influenced by installation error;Compared to upper
State the deficiency of instrument, the RTCP of R-test measuring instrument combination five-axle number control machine tool RPCP linkage function, can directly measure identification and obtain
The geometric error of rotation axis, the kinematic error of main shaft, thermal deformation errors etc. are taken, realize that the geometry of easy measurement lathe rotation axis misses
Difference;R-test measuring instrument mainly uses two kinds of measurement methods to pass through tangent displacement sensor or non-contact displacement transducer
Measuring center ball sphere centre coordinate;Very few about its research in the prior art, the research about R-test measuring instrument, which concentrates on, to be connect
Touch measurement method, wherein big bright, Li Liangliang of Liu etc. proposes the measurement of the R-test instrument using tangent displacement sensor
Principle, and analysis is optimized to its structure;Contact R-test measuring instrument Measurement Algorithm is simple, and sensor mounting location
Deviation, which will not be constituted measurement result, to be influenced, but its mechanical structure causes the reading susceptibility of sensor not high, and contact brings mill
Damage, causes measurement accuracy low.The measurement error that contactless R-test measuring instrument can generate to avoid measurement abrasion, and can be
It being measured under the conditions of main shaft high-speed rotation, sensitivity of measurement and stability are more preferable, but in the prior art to contactless R-
The research of test measuring instrument is very few;Shadow of the main performance index of contactless R-test measuring instrument by the structural parameters of measuring instrument
Sound is larger, it is therefore desirable to which a kind of method optimizes the structural parameters of contactless R-test measuring instrument, realizes contactless R-test
The high sensitivity of measurement and biggish measurement space.
Summary of the invention
It is an object of the invention to: the present invention provides a kind of structure parameter optimizing sides of contactless R-test measuring instrument
Method solves existing contact R-test measuring instrument because contact wear and mechanical structure cause measurement sensitivity difference and measurement accuracy low
The problem of.
The technical solution adopted by the invention is as follows:
A kind of structure parameter optimizing method of contactless R-test measuring instrument, includes the following steps:
Step 1: establishing the structural model of the contactless R-test measuring instrument using eddy current displacement sensor, and to knot
The coordinate of structure model is pre-processed;
Step 2: the induced voltage building measurement measured according to pretreated structural model and eddy current displacement sensor
Sensitivity equation obtains sensitivity and maximizes corresponding sensor angle of elevation alpha;
Step 3: the measurement constraint equation of each eddy current displacement sensor is calculated based on the maximized structural model of sensitivity;
Step 4: calculate simultaneously meet measurement constraint equation measurement point number measure spatial volume after, acquisition measure sky
Between the corresponding center sensor spacing λ of volume maximization, complete structure parameter optimizing.
Preferably, the step 1 includes the following steps:
Step 1.1: establishing includes equally distributed three non-contact electric eddy shift sensors and a measurement ball
Structural model;
Step 1.2: plane Δ ABC where defining three sensor bottom center points is benchmark face, sensor axis and base
The angle in quasi- face is sensor angle of elevation alpha;
Step 1.3: establishing measurement coordinate system XYZ, coordinate system Z axis is overlapped with measuring instrument central axis, and the XOY of coordinate system is sat
Mark face is parallel with datum level.
Preferably, the step 2 includes the following steps:
Step 2.1: in conjunction with pretreated structural model, according to the principle of induction and transducer calibration of current vortex sensor
Test building sensor measurement characteristic curve equation one, equation one is as follows:
Wherein, k, t, m, n, q are sensor measurement characterisitic parameter, and δ is transducer range, LiIt is the measurement centre of sphere to i-th
The distance of sensor sensing end face, riFor the centre of sphere to the distance of i-th of center sensor axis, rmaxIt can be effective for sensor
Measure permitted maximum ri, UiFor the induced voltage that i-th of sensor measures, RBallTo measure the radius of a ball;
Step 2.2: assuming that the measurement characterisitic parameter of all the sensors is consistent, measurement coordinate origin is defined as in sensor
The intersection point of mandrel line, that is, sensor elevation angle is α, and the centre of sphere is to the distance r of center sensor axisi=0, obtain following sensing
Device measures characteristic curve equation two:
Step 2.3: calculating the centre of sphere and sensor end face distance Li:
Wherein, (x, y, z) is sphere centre coordinate, ai、bi、ci、diFor each sensor sensing end face equation coefficient;
Step 2.4: by LiThe variation delta U of induced voltage, meter are calculated after substitution sensor measurement characteristic curve equation two
It is as follows to calculate formula:
Step 2.5: the variation delta U of induced voltage is subjected to mathematical distortions and obtains following formula:
Step 2.6: due to ai、bi、ci、diFor each sensor sensing end face equation coefficient, and diValue will not influence Δ U with
Δ x, Δ y, the relationship between Δ z, therefore can be sweared with any one per unit system of sensor sensing end face indicate ai、bi、ciValue
AndIt answers one group of per unit system of end face to swear according to sensor elevation angle the sense of access of measuring instrument, calculates measuring instrument
Measurement sensitivity equation, equation be based on the face XOZ:
Wherein, Δ P is the measurement micro transformation matrices of ball sphere centre coordinateΔ U is the induction that sensor measures
Voltage variety, the matrix J about sensor angle of elevation alpha indicate that the measurement micro transformation matrices Δ P of ball sphere centre coordinate and sensor are surveyed
The mapping relations between induced voltage variation delta U obtained.
Step 2.7: the inverse for defining the conditional number of the matrix J about sensor angle of elevation alpha refers to as measurement sensitivity evaluation
Prec is marked, the relation curve of measuring instrument sensitivity evaluation index Prec and sensor elevation angle a are drawn according to measurement sensitivity equation,
The maximized sensor angle of elevation alpha of sensitivity is obtained according to curve.
Preferably, the step 3 includes the following steps:
Step 3.1: deriving that sensor can be surveyed effectively based on the maximized structural model of sensitivity (being based on XOZ plane)
Measure permitted maximum riThat is rmaxEquation:
Wherein, M (x, y, z) is sensor external cylindrical surface any point, and V is sensor sensing end face normal vector, Pi-0For
Each sensor sensing end face center point, rmaxPermitted maximum r can be effectively measured for each sensori;
Step 3.2: being based on the corresponding r of sensor 3maxThe survey of sensor 3 is obtained to sensor sensing end face distance with M point
Measure constraint equation:
Wherein, RIt visitsFor sensor end radius, RBallTo measure the radius of a ball, δ is transducer range, and λ is between center sensor
Away from i.e. measuring instrument central axis at a distance from the center of circle of sensor sensing end face;
Step 3.3: being based on the corresponding r of sensor 2maxThe survey of sensor 2 is obtained to sensor sensing end face distance with M point
Measure constraint equation:
Step 3.4: being based on the corresponding r of sensor 1maxThe survey of sensor 1 is obtained to sensor sensing end face distance with M point
Measure constraint equation:
Preferably, the step 4 includes the following steps:
Step 4.1: being calculated using monte-carlo search method and meet 3 measurement constraint sides under measurement spatial volume, that is, current λ
The measurement point number of range request;
Step 4.2: the measurement space S under different λ is calculated based on step 4.1j, wherein j=1 ..., m;M is a of taken λ
Number;
Step 4.3: drawing S- λ relation curve, obtain the corresponding center sensor spacing λ of measurement volume maximization, realize
Measurement sensitivity maximizes and measurement space maximizes, and completes structure parameter optimizing.
In conclusion by adopting the above-described technical solution, the beneficial effects of the present invention are:
1. the present invention is by establishing contactless R-test structural model, by optimum structural parameter sensor angle of elevation alpha and
Center sensor spacing λ realizes that measuring instrument measurement sensitivity and measurement space maximize, solves existing contact R-test and survey
Amount instrument has reached because contact wear and mechanical structure lead to measurement sensitivity difference and the low problem of measurement accuracy and has improved measuring instrument
The effect of measurement accuracy;
2. R-test measuring instrument susceptibility of the invention refers to that the minimum centre of sphere that can generate actual induction voltage signal is mobile
Amount is related to sensor angle of elevation alpha;Plan range formula, structure are arrived according to sensor sensing voltage measurement characteristic curve equation and point
Build induced voltage UiWith measurement ball sphere centre coordinate (x, y, z) functional relationship model, to establish the variation delta U of induced voltagei
With the measurement micro transformation matrices Δ P of ball sphere centre coordinate (Δ x, Δ y, Δ z)TMatrix equation;With one group about sensor angle of elevation alpha
Per unit system arrow matrix J replace Δ U- Δ P matrix equation in sensor sensing end face plane coefficient ai、bi、ciAnd di;According to
Matrix analysis is theoretical, using the inverse of the conditional number of matrix J as measurement sensitivity evaluation index Prec, determines pair of Prec and α
It should be related to, acquisition makes the maximum sensor angle of elevation alpha of measurement sensitivity evaluation index Prec, realizes that measuring instrument measurement sensitivity is maximum
Change;
3. the maximum measurement space of the contactless R-test measuring instrument of the present invention is measurement ball centre of sphere institute energy in measurement process
The maximum magnitude of movement is related to center sensor spacing λ;On the basis of guaranteeing that measuring instrument measurement sensitivity is maximum, establish
Measurement constraint equation of each eddy current displacement sensor about center sensor spacing λ defines monte-carlo search section, benefit
The point for meeting measurement constraint equation in the region of search is found with monte-carlo search method, is put under the spacing λ of different sensors center
Number is the measurement space S of respective sensor center spacing λ, and acquisition makes to measure the maximum center sensor spacing λ of space S,
Realize that measuring instrument measurement space maximizes.
Detailed description of the invention
In order to illustrate the technical solution of the embodiments of the present invention more clearly, below will be to needed in the embodiment attached
Figure is briefly described, it should be understood that the following drawings illustrates only certain embodiments of the present invention, therefore is not construed as pair
The restriction of range for those of ordinary skill in the art without creative efforts, can also be according to this
A little attached drawings obtain other relevant attached drawings.
Fig. 1 is flow chart of the method for the present invention;
Fig. 2 is contactless R-test measuring instrument structural model figure of the invention;
Fig. 3 is sensor of the invention-measurement ball spatial relationship schematic diagram;
Fig. 4 is the graph of relation of sensitivity evaluation index Prec and sensor angle of elevation alpha of the invention;
Fig. 5 is centre of sphere motion range schematic diagram of the invention;
Fig. 6 is sensor of the invention and measurement geometry of sphere positional diagram;
Fig. 7 is measurement space S calculation flow chart of the invention;
Fig. 8 is the graph of relation of measurement space S and center sensor spacing λ of the invention.
Appended drawing reference: 1- measures ball, and 2- sensor i, 3- sensor i incudes end face, and 4- measures ball centre of sphere motion range, 5-
Sensors A, 6- sensor B, 7- sensor C, A- sensors A bottom center point, B- sensor B bottom center point, C- sensor C
Bottom center point, A1Sensors A incudes end face central point, B1Sensor B incudes end face central point, C1Sensor C induction end
Face central point.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that described herein, specific examples are only used to explain the present invention, not
For limiting the present invention, i.e., described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is logical
The component for the embodiment of the present invention being often described and illustrated herein in the accompanying drawings can be arranged and be designed with a variety of different configurations.
Therefore, the detailed description of the embodiment of the present invention provided in the accompanying drawings is not intended to limit below claimed
The scope of the present invention, but be merely representative of selected embodiment of the invention.Based on the embodiment of the present invention, those skilled in the art
Member's every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
It should be noted that the relational terms of term " first " and " second " or the like be used merely to an entity or
Operation is distinguished with another entity or operation, and without necessarily requiring or implying between these entities or operation, there are any
This actual relationship or sequence.Moreover, the terms "include", "comprise" or its any other variant be intended to it is non-exclusive
Property include so that include a series of elements process, method, article or equipment not only include those elements, but also
Further include other elements that are not explicitly listed, or further include for this process, method, article or equipment it is intrinsic
Element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that including described
There is also other identical elements in the process, method, article or equipment of element.
Technical problem: existing contact R-test measuring instrument is solved because contact wear and mechanical structure lead to measurement sensitivity
The difference problem low with measurement accuracy;
Technological means:
A kind of structure parameter optimizing method of contactless R-test measuring instrument, includes the following steps:
Step 1: establishing the structural model of the contactless R-test measuring instrument using eddy current displacement sensor, and to knot
The coordinate of structure model is pre-processed;
Step 2: the induced voltage building measurement measured according to pretreated structural model and eddy current displacement sensor
Sensitivity equation obtains sensitivity and maximizes corresponding sensor angle of elevation alpha;
Step 3: the measurement constraint equation of each eddy current displacement sensor is calculated based on the maximized structural model of sensitivity;
Step 4: calculate simultaneously meet measurement constraint equation measurement point number measure spatial volume after, acquisition measure sky
Between the corresponding center sensor spacing λ of volume maximization, complete structure parameter optimizing.
Step 1 includes the following steps:
Step 1.1: establishing includes equally distributed three non-contact electric eddy shift sensors and a measurement ball
Structural model;Three non-contact electric eddy shift sensors are respectively sensors A, sensor B and sensor C;
Step 1.2: plane Δ ABC where defining three sensor bottom center points is benchmark face, sensor axis and base
The angle in quasi- face is sensor angle of elevation alpha;
Step 1.3: establishing measurement coordinate system XYZ, coordinate system Z axis is overlapped with measuring instrument central axis, and the XOY of coordinate system is sat
Mark face is parallel with datum level.
Step 2 includes the following steps:
Step 2.1: in conjunction with pretreated structural model, according to the principle of induction and transducer calibration of current vortex sensor
Test building sensor measurement characteristic curve equation one, equation one is as follows:
Wherein, k, t, m, n, q are sensor measurement characterisitic parameter, and δ is transducer range, LiIt is the measurement centre of sphere to i-th
The distance of sensor sensing end face, riFor the centre of sphere to the distance of i-th of center sensor axis, rmaxIt can be effective for sensor
Measure permitted maximum ri, UiFor the induced voltage that i-th of sensor measures, RBallTo measure the radius of a ball;
Step 2.2: the measurement characterisitic parameter for defining all the sensors is consistent, and measurement coordinate origin is defined as in sensor
The intersection point of mandrel line, that is, sensor elevation angle is α, and the centre of sphere is to the distance r of center sensor axisi=0, obtain following sensing
Device measures characteristic curve equation two:
Step 2.3: calculating the measurement ball centre of sphere and sensor end face distance Li:
Wherein, (x, y, z) is sphere centre coordinate, ai、bi、ci、diFor each sensor sensing end face equation coefficient;
Step 2.4: by LiThe variation delta U of induced voltage, meter are calculated after substitution sensor measurement characteristic curve equation two
It is as follows to calculate formula:
Step 2.5: the variation delta U of induced voltage is subjected to mathematical distortions and obtains following formula:
Step 2.6: due to ai、bi、ci、diFor each sensor sensing end face equation coefficient, and diValue will not influence Δ U with
Δ x, Δ y, the relationship between Δ z, therefore can be sweared with any one per unit system of sensor sensing end face indicate ai、bi、ciValue
AndIt answers one group of per unit system of end face to swear according to sensor elevation angle the sense of access of measuring instrument, calculates measuring instrument
Measurement sensitivity equation, equation be based on the face XOZ:
Wherein, Δ P is the measurement micro transformation matrices of ball sphere centre coordinateΔ U is the induction that sensor measures
Voltage variety, the matrix J about sensor angle of elevation alpha indicate that the measurement micro transformation matrices Δ P of ball sphere centre coordinate and sensor are surveyed
The mapping relations between induced voltage variation delta U obtained.
Step 2.7: the inverse for defining the conditional number of the matrix J about sensor angle of elevation alpha refers to as measurement sensitivity evaluation
Prec is marked, the relation curve of measuring instrument sensitivity evaluation index Prec and sensor elevation angle a are drawn according to measurement sensitivity equation,
The maximized sensor angle of elevation alpha of sensitivity is obtained according to curve.
Step 3 includes the following steps:
Step 3.1: deriving that sensor can be surveyed effectively based on the maximized structural model of sensitivity (being based on XOZ plane)
Measure permitted maximum riThat is rmaxEquation:
Wherein, M (x, y, z) is sensor external cylindrical surface any point, and V is sensor sensing end face normal vector, Pi-0For
Each sensor sensing end face center point, rmaxPermitted maximum r can be effectively measured for each sensori;
Step 3.2: being based on the corresponding r of sensor 3maxThe survey of sensor 3 is obtained to sensor sensing end face distance with M point
Measure constraint equation:
Wherein, RIt visitsFor sensor end radius, RBallTo measure the radius of a ball, δ is transducer range, and λ is between center sensor
Away from i.e. measuring instrument central axis at a distance from the center of circle of sensor sensing end face;
Step 3.3: being based on the corresponding r of sensor 2maxThe survey of sensor 2 is obtained to sensor sensing end face distance with M point
Measure constraint equation:
Step 3.4: being based on the corresponding r of sensor 1maxThe survey of sensor 1 is obtained to sensor sensing end face distance with M point
Measure constraint equation:
Step 4 includes the following steps:
Step 4.1: being calculated using monte-carlo search method and meet 3 measurement constraint sides under measurement spatial volume, that is, current λ
The measurement point number of range request;
Step 4.2: the measurement space S under different λ is calculated based on step 4.1j, wherein j=1 ..., m;M is a of taken λ
Number;
Step 4.3: drawing S- λ relation curve, obtain the corresponding center sensor spacing λ of measurement volume maximization, realize
Measurement sensitivity maximizes and measurement space maximizes, and completes structure parameter optimizing.
Technical effect: by establishing contactless R-test structural model, by optimum structural parameter sensor angle of elevation alpha and
Center sensor spacing λ realizes that measuring instrument measurement sensitivity and measurement space maximize, solves existing contact R-test and survey
Amount instrument has reached because contact wear and mechanical structure lead to measurement sensitivity difference and the low problem of measurement accuracy and has improved measuring instrument
The effect of measurement accuracy;
Feature and performance of the invention are described in further detail with reference to embodiments.
Embodiment 1
As shown in Fig. 2,3,5 and 6, establishing includes equally distributed three non-contact electric eddy shift sensors and one
Measure the structural model of ball 1;Three non-contact electric eddy shift sensors are respectively sensors A 5, sensor B6 and sensor
C7;As shown in figure 4, the measurement sensitivity index Prec of contactless R-test measuring instrument with the variation of sensor angle of elevation alpha and
Change, monotone decreasing after first monotonic increase is determined when α=33.69 °, and measurement sensitivity index Prec reaches maximum;Guaranteeing
(α=33.69 ° are taken) on the basis of measurement sensitivity, between the measurement space S and center sensor of contactless R-test measuring instrument
Relationship (r away from λmax=4mm, RIt visits=7mm, RBall=15mm, δ=4mm) as depicted in figure 8, it determines as λ=14mm, measures space S
Maximum, about 33mm3。
The calculation process for measuring spatial volume S is as follows, and flow chart is as shown in Figure 7:
(1) region of search: x [x is definedmin,xmax], y [ymin,ymax], z [zmin,zmax](xmin、xmax、ymin、ymax、zmin、
zmaxValue should ensure that can cover all point sections met the requirements);
(2) using unit length as step-length, the above-mentioned region of search is divided into n measurement point set, measurement point is defined as Pi
(i=1 ..., n);
(3) α=33.69 ° are set, in [RIt visits, RBall+ δ] in range with λ0λ (λ is successively taken for step-length0=1mm);
(4) by measurement point PiTogether with parameter rmax、RIt visits、RBall, δ, α substitute into the measurement constraint equation of sensor 1,2,3 together;
If meeting constraint equation (9), (10), (11) simultaneously, show PiIn effective centre of sphere motion range;
(5) measurement space S is equal to and meets the measurement point number that 3 measurement constraint equations require under current λ;
(6) the measurement space S under different λ can be obtained by repeating step (3)-(5)j(j=1 ..., m;M for taken λ number).
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention
Made any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.