Summary of the invention
This paper has proposed a kind of measuring method of the two-dimensional contour shape that does not rely on coordinate and has realized a kind of measurement mechanism that does not rely on the two-dimensional contour shape of coordinate based on the method, thus solve limit of range that the measurement range that exists in the above prior art is subjected to measurement mechanism, measure the preparatory stage long, the measurement mechanism volume is very big and carry inconvenience and measurement mechanism problem such as cost an arm and a leg.
Therefore, at first the present invention proposes a kind of measuring method that does not rely on the two-dimensional contour shape of coordinate, it is characterized in that comprising the steps:
On step a, the selection testee two-dimensional silhouette certain is a bit for measuring starting point;
Step b, measure the two-dimentional accumulated angular length of the described relatively measurement starting point of each point on the testee two-dimensional silhouette and approximate curvature that should two dimension accumulated angular length correspondence;
The two-dimensional contour shape that step C, the two-dimentional accumulated angular length that obtains according to step a and the relation between the approximate curvature thereof reconstruct Measuring Object.
The present invention proposes a kind of new measuring method of two-dimensional contour shape, can be by adopting based on the measurement mechanism of this method realization and the relative motion between the testee profile, obtain the arc length and the curvature data of position, go out the contour shape of Measuring Object by the parameter reconstruct of these two sign curve characteristics.Described approximate curvature is meant certain location bending degree of testee two-dimensional silhouette, and the structural parameters of the device of realizing by the local deformation of testee profile amount and based on this method are calculated, are the approximate values of physical location curvature.The core of this method is to realize a kind of mathematical model, the needed critical data in the process of reconstruct testee of this model is the arc length and the curvature data of testee profile, these two data are irrelevant with coordinate, can calculate the contour shape of object like this by these two data.
Secondly, the present invention proposes a kind of measurement mechanism based on this measuring method, comprising:
Measurement module is used for directly contacting with testee, obtains the arc length and the deflection of each measuring point;
Processing module is used to handle arc length and deflection, the shape of reconstruct testee, and provide corresponding analysis diagram.
Acquisition module is used for the interface between measurement module and the processing module, obtains data from measurement module, and the data that collect are sent to processing module, is made up of data collecting card or data acquisition instrument.
As a kind of possibility, described measurement module is made up of first sensory package, second sensor, first support, second support, base, described first support, second support are installed in described base two ends respectively, described first sensor assembly is installed in the described second support lower end, described second sensor is installed on the base between described first support, second support, and described first support, second support, second sensor are all on same surface level; Described first sensor assembly comprises angular transducer and roller, wherein roller is connected with the rotating shaft interference of sensor, when measuring, described roller contacts with the testee profile phase, and along doing the rotation of fricton-tight rolling drive angular transducer on the testee profile, described angular transducer is constantly sampled and is obtained the accumulated angular length value of each point on the profile; Described second sensor is a displacement transducer, is used to measure the approximate curvature of the accumulated angular length correspondence of each point.
As alternative dispensing means, described measurement module is made up of first sensory package, second sensor, first support, second support, base, described first support, second support are installed in described base two ends respectively, described second sensor is installed on the base between described first support, second support, described first sensor assembly is installed in the described second sensor lower end, and described first support, second support, second sensor are all on same surface level; Described first sensor assembly comprises angular transducer and roller, wherein roller is connected with the rotating shaft interference of sensor, when measuring, described roller contacts with the testee profile phase, and along doing the rotation of fricton-tight rolling drive angular transducer on the testee profile, described angular transducer is constantly sampled and is obtained the accumulated angular length value of each point on the profile; Described second sensor is a displacement transducer, is used to measure the approximate curvature of the accumulated angular length correspondence of each point.
As the third possibility, described measurement module is made up of first sensory package, second sensor, first support, second support, base, described first support, second support are installed in described base two ends respectively, described first sensor is installed on the base between described first support, second support, described second sensor module is installed in the described second support lower end, and described first support, second support, second sensor are all on same surface level; Described first sensor assembly comprises angular transducer and roller, wherein roller is connected with the rotating shaft interference of sensor, when measuring, described roller contacts with the testee profile phase, and along doing the rotation of fricton-tight rolling drive angular transducer on the testee profile, described angular transducer is constantly sampled and is obtained the accumulated angular length value of each point on the profile; Described second sensor is a displacement transducer, is used to measure the approximate curvature of the accumulated angular length correspondence of each point.
In above-mentioned three kinds of structures, described roller roller adopts friction factor bigger, thus the strong material of anti-pressure ability for example nylon make that the roller deflection is little when measuring, and move along testee surface pure rolling.
Described curvature is that the realtime deformation by the positional structure design between support, roller and the displacement transducer three and calibrating parameters and displacement transducer calculates; Arc length is to be calculated by the real-time measuring data that roller drive angular transducer rotates.The deflection of the displacement transducer that the spacing between roller, displacement transducer and the support three contacts fully by several groups of round standard components and three and the diameter inverse of circle standard component push away, and the diameter of roller adopts vernier caliper measurement to obtain simultaneously.
Described processing module is made of computing machine and corresponding Measurement and Data Processing software, and wherein computing machine can be desktop computer or notebook computer, and its configuration comprises processor, reservoir, input-output device and communication interface.
Described Measurement and Data Processing software package contains curvature calculating, arc length analysis, data smoothing, curve Reconstruction, outline, error analysis, location position, measuring object information and shows, revises, deletes and preserve these functions.By filter preprocessing to the magnitude of voltage of the displacement transducer gathered, the count value of magnitude of voltage and scrambler is converted to gauge head displacement and arc length, with the apparatus structure parameter of gauge head displacement and demarcation and the measurement diameter Simultaneous Equations of roller, thereby obtain radius-of-curvature information, radius-of-curvature is corresponding with the arc length that measures, thereby the shape to Measuring Object is carried out fitting reconfiguration, obtain actual contour shape, the center of gravity of the geometric configuration that match is obtained overlaps with the center of gravity of actual tested shape to be done shape and mates, thereby carries out correlation analysis and error analysis.This software has a display interface simultaneously, can show the measured shape data that obtains in real time.In addition, this software also contains the database that is useful on preservation measurement data and analysis result, thereby manages the metrical information and the analytical information of each measuring object.
Described acquisition module is connected with measurement module and processing module.The arc length data of the everywhere that measures and profile deflection all are to send to harvester in real time.And by RS232 serial ports or pci interface communication between the computing machine, arc length data and the profile deflection that collects is transmitted to computing machine in real time.
Therefore the present invention proposes a kind of measuring method and measurement mechanism of two-dimensional contour shape, make the size of measurand not be subjected to the limit of range of measurement mechanism, more convenient in two-dimensional contour shape is measured.
Embodiment:
Pass through to measure the arc length of testee profile and the method that curvature data comes the reconstruction of objects shape with what for example mode provided that the present invention determines below.
Be illustrated in figure 1 as based on the arc method of arc length and curvature and approach the reconstruct synoptic diagram.
Since circular arc to the degree of approximation of curve than the degree of approximation height of straight-line segment to curve, thereby circular arc is littler than straight-line segment to the approximate error of curve, chooses circular arc here as the minimum unit in the curve Reconstruction, thereby guarantee that curve is that G1 is continuous after the reconstruct.
It below is algorithm steps with the circular arc restructuring procedure.
Step 1. is set the coordinate system of restructuring procedure.
For reconstruct curve in data processing software, therefore measurement must be set up the reconstruct coordinate system, notice that the coordinate system here has no relation with measuring process, only be in order to satisfy the needs of data point location and the process of mapping in the software reconfiguration.
As shown in Figure 1, the curve that reconstructs is by n arc section o
0o
1, o
1o
2..., o
N-1o
nConstitute.To measure starting point O
0As the true origin of global coordinate system OXY, this is the reference origin of other all coordinate systems, and every section circular arc all has a local coordinate system o
ix
iy
i, wherein the starting point of local coordinate system is respectively o
ix
iy
iThe initial point o of coordinate system
i, and the x axle of local coordinate system is tangent with corresponding arc section.Global coordinate system OXY and local coordinate system o like this
0Xy (o wherein
0Xy is the local coordinate system of starting point) coincide i.e. O
0True origin in global coordinate system and local coordinate system.
Step 2. is calculated the coordinate figure of each arc section end points in global coordinate system, and the arc radius of each arc section.
By step 1 O as can be known
0Coordinate in global coordinate system and local coordinate system all is (0,0).
Other o
iCoordinate figure and o
I-1With o
iBetween arc radius computation process:
(1). the angular displacement that records by first sensor
iValue calculates the corresponding accumulated angular length S of i section
iValue.
ΔS
i=k
sθ
i(i=1,2,3,…,n) (1)
K wherein
sBe the conversion constant between angular displacement and the arc length, before measurement by the apparatus structure parameter calibration.
(2). by S
iWith S
I+1Calculate the corresponding arc length increment Delta of i section S
iValue.
Wherein: Δ S
i=S
I+1-S
i(i=1,2,3 ..., n-1) (2)
(3). the arc of each position of corresponding testee profile that is obtained by second sensor measurement is risen Δ h
iValue calculate the radius of curvature R that corresponding i is ordered
i
R
i=k
rΔh
i(i=1,2,3,…,n) (3)
K wherein
sBe arc rise and radius-of-curvature between conversion constant, before measurement, demarcate by standard component.
(4). the calculated value according to 1 and 2, utilize formula to obtain the camber line angle θ of i section
i
θ
i=R
iΔS
i (4)
(5). calculate circular arc terminal point coordinate (x in local coordinate system of i section
i, y
i), its result is as follows:
(6). the local coordinate that i is ordered is transformed into starting point O
0Global coordinate system in, its transition matrix is
Wherein
The reconstruct of step 3. arc method
The coordinate figure of the terminal point in global coordinate system according to i-1 section that obtains and i section circular arc, the arc radius of the i section that integrating step 2 obtains just can obtain the arc of i section.Successively these arcs are coupled together then, just obtain the contour of object shape of measuring.
Need to prove, only choosing circular arc above by way of example is example as a kind of mode of curve fitting reconstruct, can also be by passing through certain data-switching with other such as straight line by arc length and curvature data, the mode of two circular arcs, polynomial expression, B batten or NUBRUS SPL is come the fitting reconfiguration contour shape.
Illustrate the measurement mechanism of realizing based on this method below and measure embodiment.
Be illustrated in figure 2 as the structural representation and the instrumentation plan of photoelectric encoder forward type measurement mechanism.
This measurement mechanism is made up of three modules: measurement module 101, acquisition module 102 and processing module 103.
Wherein measurement module 101 comprises a base, be installed in the first sensor assembly 20 on this base, comprise photoelectric encoder and the coaxial with it roller that connects altogether, be installed in the support 30 on the firm banking, second sensor 10 that is installed on this base is linear movement pick-up, the roller on the first sensor assembly 20 wherein, support 30 and displacement transducer 10 threes are positioned at same plane, three's relative position is the centre that linear movement pick-up 10 is positioned at first sensor assembly 20 and support 30, and first sensor assembly 20 can be intercoursed with the position of support 30.
Acquisition module 102 is made up of an I/O interface board and data collecting card.
Processing module 103 can be a PC, and the software by the analysis data of installation on it reconstructs contour of object thereby carry out data processing, wherein the operation of software is carried out interactive operation by keyboard 70 or mouse 80 with the man-machine interface of data processing software.
Be that signal wire by the photoelectric encoder in linear movement pick-up 10 and the first sensor assembly 20 is connected between acquisition module 102 and the measurement module, can link to each other by pci interface or serial ports between acquisition module 102 and the processing module.
Measuring method under this photoelectric encoder forward type measurement structure pattern may further comprise the steps:
Step 1: calibrating parameters
For the electrical signal conversion of photoelectric encoder in the first sensor assembly 20 that measures and linear movement pick-up 10 being become corresponding radian that can characterize contour feature and curvature information, need demarcate the structural parameters and the conversion coefficient of device.Concrete grammar is as follows:
Spacing L1 between spacing L between first sensor assembly 20 and the support 30, linear movement pick-up 10 and the support 30 can demarcate respectively by the round standard component of several groups of different-diameters and draw.
Get the round standard component of one of them diameter, it is contacted with roller side, the top of top and linear movement pick-up 10 of support 30 on the first sensor assembly 20 simultaneously, note the reading of linear movement pick-up 10 of this moment and the diameter of employed round standard component.According to this method, demarcate with other several groups round standard components, by a series of record, set up the structural parameters that system of equations is come solving device.In addition with first sensor assembly 20 on roller diameter adopt vernier caliper measurement to obtain.
This calibration process only needs once get final product, need all not demarcate when Measuring Object at every turn, unless the structure of this measurement mechanism changes.
Step 2: measure shape
Measurement is to make testee and measurement mechanism produce relative motion, thereby obtains a process of measurement data continuously.According to the implementation of relative motion, following two kinds of methods are arranged:
A. measurement mechanism motion, measurand is static: for the bigger object of profile, generally adopt the method.Its operation steps is as follows:
Object 40 is maintained static, then with holding this measurement module 101, make the roller in photoelectric encoder 20 rotating shafts, the top three top, linear movement pick-up 10 of support 30 can contact object 40 simultaneously, apply certain pressure then, and measurement mechanism 101 is moved along body surface 40, the top moment that guarantees the top and linear movement pick-up 10 of support 30 simultaneously contacts with object 40 and moves in the mode of pure rolling with roller on the first sensor assembly 20 as far as possible.In the process of motion, when roller constantly rolls, photoelectric encoder 20 constantly obtains the distances that roller rolled across, and promptly with respect to the distance of the initial contact point of roller and curve, isochrone displacement transducer 10 constantly records the pairing arc value of rising of C point to the C point on curve.
B. measurand motion, measurement mechanism is static: for less object, such as general cam, generally adopt the method.The difference of its operation steps and method a is, when measuring, measurement mechanism is maintained static, manually controls testee 40, make its outline constantly with first sensor assembly 20 on roller, the top three top, linear movement pick-up 10 of support 30 contact constantly.
Step 3: data smoothing is handled
After measurement module 101 obtains data, give processing module by acquisition module 102 with data transfer, 103 pairs of data that collect of processing module will be carried out suitable processing, just can obtain comparatively ideal contour curve.
Because the fluctuating error that operational measure device and linear movement pick-up or photoelectric encoder bring need carry out The disposal of gentle filter to the data that measure, adopt polynomial expression or other wave filter to carry out smoothing processing in order to reduce in the measuring process here.
Step 4: reconstruct two-dimensional contour shape
Utilize the circular arc restructing algorithm of Fig. 1, choose certain section length, the data after handling through step 3 are carried out curve Reconstruction, the measurement shape after obtaining handling for the first time.The part that initial roller is not touched is utilized the position of the roller contact point on initial and the first sensor assembly 20 and is cut the reading of arrow, start line displacement transducer 10, parameter L, the L1 that structure is demarcated simultaneously, can determine.
Step 5: display result
By the shape after the reconstruct, directly be presented on the display 50 of processing module.
Be illustrated in figure 3 as the structural representation and the instrumentation plan of photoelectric encoder and linear movement pick-up superposing type measurement mechanism.
This measurement mechanism is made up of three modules: measurement module 101, acquisition module 102 and processing module 103.
Different among its structure and Fig. 1 is mobile top the linking to each other of roller wheel shaft with the linear movement pick-up 10 of first sensor assembly 20.Simultaneously compared to Figure 1, its support top about 30 is respectively one.The structure of other parts is identical with the roller forward type.
Measuring method under this photoelectric encoder and linear movement pick-up superposing type may further comprise the steps:
Step 1: calibrating parameters
For the electrical signal conversion of photoelectric encoder in the first sensor assembly 20 that measures and linear movement pick-up 10 being become corresponding radian that can characterize contour feature and curvature information, need demarcate the structural parameters and the conversion coefficient of device.Concrete grammar is as follows:
Spacing L1 between spacing L between left socle 30 and the right support 30, linear movement pick-up 10 (or first sensor assembly 20) and the support 30 can demarcate respectively by the round standard component of several groups of different-diameters and draw.
Its scaling method is identical with the preposition method of roller.
Step 2: measure shape
Measurement is to make testee and measurement mechanism produce relative motion, thereby obtains a process of measurement data continuously.According to the implementation of relative motion, following two kinds of methods are arranged:
A. measurement mechanism motion, measurand is static: for the bigger object of profile, generally adopt the method.Its operation steps is as follows:
Object 40 is maintained static, then with holding this measurement module 101, make the roller in the first sensor assembly 20, the top three top, right support 30 of left socle 30 can contact object 40 simultaneously, apply certain pressure then, and measurement mechanism 101 is moved along body surface 40, the top moment that guarantees left and right sides support 30 simultaneously contacts with object 40 and moves in the mode of pure rolling with roller in the first sensor assembly 20 as far as possible.In the process of motion, when roller constantly rolls, the distance that photoelectric encoder in the first sensor assembly 20 constantly obtains roller and rolled across, be C point distance with respect to the initial contact point of roller and curve on curve, isochrone displacement transducer 10 constantly records the pairing arc value of rising of C point.
B. measurand motion, measurement mechanism is static: for less object, such as general cam, generally adopt the method.The difference of its operation steps and method a is, when measuring, measurement mechanism is maintained static, and manually controls testee 40, and its outline is contacted constantly with the top three top, linear movement pick-up 10 of left and right sides support 30 constantly.
Step 3: smoothed data
Identical with the method for roller forward type structure.
Step 4: reconstruct shape
Different with the reconstruct of roller forward type is for the last measurement start-up portion and the boundary treatment of latter end in the reconstruct shape.The not contacted curved portion of roller that in this programme, needs two parts of completion head and the tail.
Step 5: the result shows
By the shape after the reconstruct, directly be presented on the display 50 of processing module.
Be illustrated in figure 4 as the structural representation and the instrumentation plan of linear movement pick-up forward type measurement mechanism.
This measurement mechanism is made up of three modules: measurement module 101, acquisition module 102 and processing module 103.
Different among its structure and Fig. 1 is that first sensor assembly 20 is exchanged with the position of linear movement pick-up 10, and the structure of other parts is identical with the roller forward type.
Measuring method under this linear movement pick-up superposing type may further comprise the steps:
Step 1: calibrating parameters
For the electrical signal conversion of photoelectric encoder in the first sensor assembly 20 that measures and linear movement pick-up 10 being become corresponding radian that can characterize contour feature and curvature information, need demarcate the structural parameters and the conversion coefficient of device.Concrete grammar is as follows:
Spacing L1 between spacing L between support 30 and the linear movement pick-up 10, support 30 and the first sensor assembly 20 can demarcate respectively by the round standard component of several groups of different-diameters and draw.
Its scaling method is identical with the preposition method of roller.
Step 2: measure shape
Identical with the method for roller forward type structure.
Step 3: smoothed data
Identical with the method for roller forward type structure.
Step 4: reconstruct shape
Different with the reconstruct of roller forward type is for the last measurement start-up portion and the boundary treatment of latter end in the reconstruct shape.The not contacted curved portion of roller that in this programme, needs the completion start-up portion.
Step 5: the result shows
By the shape after the reconstruct, directly be presented on the display 50 of processing module.
Only illustrated by way of example above according to two kinds of devices and measuring process separately based on testee profile arc length and curvature reconstruction of objects profile, but the insider be it is evident that, it is described that the measuring method of accumulated angular length or approximate curvature is not limited to said apparatus, but can adopt multiple sensors, multiple roller such as ball, multiple material etc. to reach desired measurement requirement according to the many indexs such as complexity, measuring accuracy and applied environment of the profile of measurand.In other words, the cited method of the foregoing description is illustrative rather than restrictive, under the condition that does not deviate from spirit and scope of the invention, can adopt multiple different measuring method, and these measuring methods is all within category of the present invention.