CN112525130B - Contact type local curvature characteristic measuring method and system - Google Patents
Contact type local curvature characteristic measuring method and system Download PDFInfo
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- CN112525130B CN112525130B CN202011144783.2A CN202011144783A CN112525130B CN 112525130 B CN112525130 B CN 112525130B CN 202011144783 A CN202011144783 A CN 202011144783A CN 112525130 B CN112525130 B CN 112525130B
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- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/20—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring contours or curvatures, e.g. determining profile
Abstract
The application discloses a method and a system for measuring contact type local curvature characteristics, wherein the method comprises the following steps: the contact type pressing ring surface is contacted with a specific position to be processed of the workpiece; acquiring distance information of a plurality of points to be measured around the current workpiece ring surface by using a distance sensor array, and calculating orientation characteristics of the current curved surface according to the distance information, wherein the orientation characteristics comprise local normal vector directions of the point positions to be measured; and calculating the curvature characteristics of the workpiece curved surface corresponding to the current compression ring surface by using the normal vector, the distribution characteristics of the distance sensors and the measurement indication values, wherein the curvature characteristics comprise a main curvature radius, a main curvature direction, an average curvature and a Gaussian curvature so as to fit a local curved surface by using a quadric surface. According to the method for measuring the contact type local curvature characteristics, the curvature characteristics of the workpiece are measured through the distance sensor array on the tail end mechanism, and the machining precision and efficiency of the existing automatic machining equipment under complex working conditions of weak rigidity of the workpiece, unknown appearance and the like can be improved.
Description
Technical Field
The application relates to the technical field of machining detection in automatic equipment and manufacturing, in particular to a method and a system for measuring contact type local curvature characteristics.
Background
In the modern automatic manufacturing equipment process, particularly in the aerospace field, the automobile field and the ship field, parts with complex curved surface shapes need to be processed, and an important problem for the parts with complex shapes is that the actual shape and the shape of the part may not accord with the theoretical shape in a digital-analog model, so that processing errors are caused; for parts with such features, shape detection is typically performed before machining and registered with the actual digital model to obtain the curved surface features of the machined locations. Furthermore, a detection system with a compact structure is directly attached to the front end of the machining mechanism, and the curved surface characteristics of the workpiece are measured before machining, so that the automatic manufacturing efficiency can be effectively improved, and meanwhile, the links of external measurement and registration are omitted, and the production is accelerated; meanwhile, when the machining mechanism is tightly pressed on the surface of the position to be machined of the workpiece, the influence of the flexural deformation of the workpiece with weak rigidity on the measured data is low, and the measurement precision is high, so that the precision is improved. In this process, the measurement system is required to be as compact as possible, can be attached to the front end of the machining system, and can be attached to a workpiece with a complex shape, and measurement can be rapidly completed. The tail end mechanism can finish measurement in the middle of the pressing process, does not need equipment to replace stations and the like, improves the processing efficiency, ensures the stability of the positioning process that the processing equipment partially presses the workpiece, and is beneficial to improving the precision of the processing position.
Content of application
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, a first objective of the present invention is to provide a method for measuring contact-type local curvature characteristics, which can fit local curved surfaces into a spatial two-dimensional curved surface with high accuracy and extract curvature to compensate for higher processing accuracy on the basis of the conventional normal vector orientation function of the measured curved surface.
A second object of the present invention is to provide a contact local curvature characteristic measuring system.
A third object of the invention is to propose an electronic device.
A fourth object of the invention is to propose a computer-readable storage medium.
In order to achieve the above object, an embodiment of the first aspect of the present application provides a method for measuring a contact-type local curvature characteristic, including the following steps:
the contact type pressing ring surface is contacted with a specific position to be processed of the workpiece;
acquiring distance information of a plurality of points to be measured around the current workpiece ring surface by using a distance sensor array, and calculating orientation characteristics of the current curved surface according to the distance information, wherein the orientation characteristics comprise local normal vector directions of the points to be measured;
and calculating curvature characteristics of the workpiece curved surface corresponding to the current compression ring surface by using the normal vector, the distribution characteristics of the distance sensors and the measured indication values, wherein the curvature characteristics comprise a main curvature radius, a main curvature direction, an average curvature and a Gaussian curvature so as to fit a local curved surface by using a quadric surface.
In addition, the method for measuring the contact local curvature characteristic according to the above embodiment of the present invention may further have the following additional technical features:
optionally, the contacting with the workpiece at the specific position to be processed by using the contact type pressing ring surface comprises:
controlling the pressing ring surface to be tightly attached to the surface of the workpiece under driving so that the pressing ring surface is stably contacted with the curved surface of the workpiece;
taking the measured data as a limiting condition, and taking the compaction ring surface as a reference to establish a measurement coordinate system;
and constructing a vector mapping relation of the measurement data in a measurement coordinate system space according to the mounting calibration information of the distance sensor on the tail end mechanism.
Optionally, the obtaining distance information of several points to be measured around the current workpiece ring surface by using the distance sensor array, and calculating the orientation feature of the current curved surface according to the distance information includes:
matching data of symmetrical distance sensor installation spaces in data measured by a distance sensor array for difference to obtain data points of sections of the curved surface to be measured in different distance sensor directions in the space;
obtaining the skew relation of a plurality of sections of the curved surface relative to a measurement coordinate system according to the distribution characteristics of the distance sensors and the data difference values;
and solving according to the deflection relation to obtain the data of the local normal vector of the position to be measured of the workpiece in the measuring coordinate system.
Optionally, the calculating the curvature characteristic of the curved surface of the workpiece corresponding to the current compression ring surface by using the normal vector, the distribution characteristic of the distance sensor and the measurement indication value includes:
and filtering the distance sensor deviation caused by the normal vector from the distance sensor measurement indicating value to reserve the deviation caused by the curvature characteristic, comparing the deviation with the calibration data, fitting to obtain a quadratic space curved surface through the deviation data caused by the curvature of the distance sensor array, and analyzing to obtain each curvature characteristic of the local space curved surface.
In order to achieve the above object, an embodiment of a second aspect of the present application provides a contact local curvature characteristic measurement system, including:
the pressing module is used for contacting the specific position to be processed of the workpiece by utilizing the contact type pressing ring surface;
the measuring module is used for acquiring distance information of a plurality of points to be measured around the current workpiece ring surface by using the distance sensor array and calculating the orientation characteristic of the current curved surface according to the distance information, wherein the orientation characteristic comprises the local normal vector direction of the point to be measured;
and the calculation module is used for calculating the curvature characteristics of the workpiece curved surface corresponding to the current compression ring surface by using the normal vector, the distribution characteristics of the distance sensors and the measurement indicating values, wherein the curvature characteristics comprise a main curvature radius, a main curvature orientation, an average curvature and a Gaussian curvature so as to fit the local curved surface by using a quadric surface.
Optionally, the pressing module is specifically configured to:
controlling the pressing ring surface to be tightly attached to the surface of the workpiece under driving so that the pressing ring surface is stably contacted with the curved surface of the workpiece;
taking the measured data as a limiting condition, and taking the compaction ring surface as a reference to establish a measurement coordinate system;
and constructing a vector mapping relation of the measurement data in a measurement coordinate system space according to the mounting calibration information of the distance sensor on the tail end mechanism.
Optionally, the measurement module is specifically configured to:
matching data of symmetrical distance sensor installation spaces in data measured by a distance sensor array for difference to obtain data points of sections of the curved surface to be measured in different distance sensor directions in the space;
obtaining the skew relation of a plurality of sections of the curved surface relative to a measurement coordinate system according to the distribution characteristics of the distance sensors and the data difference values;
and solving according to the deflection relation to obtain the data of the local normal vector of the position to be measured of the workpiece in the measuring coordinate system.
Optionally, the calculation module is specifically configured to:
and filtering the distance sensor deviation caused by the normal vector from the distance sensor measurement indicating value to reserve the deviation caused by the curvature characteristic, comparing the deviation with the calibration data, fitting to obtain a quadratic space curved surface through the deviation data caused by the curvature of the distance sensor array, and analyzing to obtain each curvature characteristic of the local space curved surface.
To achieve the above object, an embodiment of a third aspect of the present application provides an electronic device, including: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being configured to perform a method of measuring a contact local curvature characteristic as described in the above embodiments.
In order to achieve the above object, a fourth aspect of the present application provides a computer-readable storage medium storing computer instructions for causing a computer to execute the method for measuring a contact local curvature characteristic according to the above embodiment.
Therefore, the local part of the workpiece to be measured is tightly attached to the pressing ring surface, the point location information of the surface of the workpiece measured by the distance sensor array under the measurement coordinate system is used for calculating the curvature characteristic of the surface of the current workpiece, and the calculated data is used in the subsequent processing process, so that the processing precision of the automatic drilling equipment is improved.
Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.
Drawings
The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a flow chart of a method for measuring a contact local curvature characteristic according to an embodiment of the present application;
FIG. 2 is a flow chart of an implementation of a method of contact local curvature measurement according to one embodiment of the present application;
FIG. 3 is a schematic view of a measurement system according to one embodiment of the present application in which a contact local measurement method is developed;
FIG. 4 illustrates a distance sensor arrangement and a coordinate system construction according to one embodiment of the present application, as developed by a contact local measurement method;
FIG. 5 is an example of measurements on a secondary hyperboloid in a simulation environment according to one embodiment of the present application;
FIG. 6 is an exemplary diagram of a contact local curvature feature measurement device according to an embodiment of the present application;
FIG. 7 is an exemplary diagram of a contact local curvature feature measurement device according to one embodiment of the present application;
fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Detailed Description
Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.
The method and system for measuring a contact-type local curvature characteristic according to an embodiment of the present invention will be described below with reference to the accompanying drawings, and first, the method for measuring a contact-type local curvature characteristic according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Specifically, fig. 1 is a schematic flowchart of a method for measuring a contact local curvature feature according to an embodiment of the present disclosure.
As shown in fig. 1, the method for measuring the contact local curvature characteristic comprises the following steps:
in step S101, the contact type pressing ring surface is used to contact with a specific to-be-processed position of the workpiece.
Optionally, the contact type pressing ring surface is contacted with the specific position to be processed of the workpiece, and the contact type pressing ring surface comprises: the pressing ring surface is controlled to be tightly attached to the surface of the workpiece under driving, so that the pressing ring surface is stably contacted with the curved surface of the workpiece; taking the measured data as a limiting condition, and taking the compaction ring surface as a reference to establish a measurement coordinate system; and constructing a vector mapping relation of the measurement data in a measurement coordinate system space according to the mounting calibration information of the distance sensor on the tail end mechanism.
It is understood that, in conjunction with fig. 2 and 3, step S1 includes: the pressing ring surface 1 is tightly attached to the surface of a workpiece under driving, and the pressing ring surface is stably contacted with the curved surface of the workpiece; taking the measured data as a limiting condition, and taking the compaction ring surface as a reference to establish a measurement coordinate system; and constructing a vector mapping relation of the measurement data in a measurement coordinate system space according to the installation calibration information of the distance sensor 2 on the end mechanism 3.
It should be noted that the end mechanism of the embodiment is oriented to specific processing requirements, the compression ring surface 1 presents a concentric circle shape, and the non-contact distance sensor 2 array is adopted for measurement in consideration of the measurement requirements of specific materials. It should be emphasized at this time that this measuring method is not only applicable to the distance sensor array shown in fig. 3, but also applicable to various distance sensors including contact type length gauges, non-contact type laser sensors, electromagnetic sensors, and the like. At this time, the measurement coordinate system is established based on the compression ring surface 1, and in the embodiment, the position of the center of the compression ring surface 1. After the installation is finished, the position of the array of distance sensors 2 on the end mechanism 3 is calibrated to obtain the position of the measurement point in the measurement coordinate system referenced to the compression ring surface 1.
In step S102, distance information of several points to be measured around the current workpiece torus is acquired by using the distance sensor array, and an orientation feature of the current curved surface is calculated according to the distance information, wherein the orientation feature includes a local normal vector direction of a point to be measured.
Optionally, the step of obtaining distance information of several points to be measured around the current workpiece ring surface by using the distance sensor array, and calculating the orientation characteristic of the current curved surface according to the distance information includes: matching data of symmetrical distance sensor installation spaces in data measured by a distance sensor array for difference to obtain data points of sections of the curved surface to be measured in different distance sensor directions in the space; obtaining the skew relation of a plurality of sections of the curved surface relative to a measurement coordinate system according to the distribution characteristics of the distance sensors and the data difference values; and solving according to the deviation relation to obtain the data of the local normal vector of the position to be measured of the workpiece in the measuring coordinate system.
It is understood that, in conjunction with fig. 2 and 4, in an embodiment, step S2 includes: matching data which are symmetrical in installation space of the distance sensors in the data measured by the distance sensor array to obtain difference values, and obtaining data points of sections of the curved surface to be measured in different distance sensor directions in the space; and obtaining the skew relation of a plurality of sections of the curved surface relative to the measuring coordinate system according to the distribution characteristics of the distance sensors and the data difference values; and solving according to the deviation relation to obtain the data of the local normal vector of the position to be measured of the workpiece in the measuring coordinate system.
It should be noted that, in the embodiment, the distance sensor array includes six symmetrical distance sensors, the mounting controls of the distance sensor array symmetrically include three pairs of distance sensors, as shown in fig. 4, the distance sensors are 2.1 to 2.6, the pairing mode is 2.1 for 2.4, 2.2 for 2.5, and 2.3 for 2.6, the data of the distance sensors is the vertical distance of the distance sensors themselves perpendicular to the xy plane of the measurement coordinate system, and through conversion of calibration information, the three-dimensional coordinate vector of the measurement point of the distance sensor, that is, the corresponding point on the curved surface of the workpiece in the measurement coordinate system can be obtained, and further, the skew relationship between the cross section where the opposing distance sensor is located and the measurement coordinate system can be obtained. It should be noted that the cross-section of the sets of range sensor measurement points should be perpendicular to the xy-plane and pass through the z-axis of the coordinate system. The cross section deflection relation refers to an included angle between a connecting line of measuring points of the opposite distance sensors in a measuring coordinate system and an xy plane of the measuring coordinate system, and further, under the condition that deflection information of a plurality of groups of distance sensors is known, the normal vector direction and the space expression of the cross section can be calculated.
In step S103, curvature characteristics of the workpiece curved surface corresponding to the current compression ring surface are calculated using the normal vector, the distribution characteristics of the distance sensor, and the measurement indication, where the curvature characteristics include a principal curvature radius, a principal curvature orientation, an average curvature, and a gaussian curvature, so as to fit the local curved surface with a quadratic surface.
Optionally, calculating the curvature characteristic of the current packing annulus using the normal vector, the distance sensor distribution characteristic, and the measurement indication, comprises: and filtering the distance sensor deviation caused by the normal vector from the distance sensor measurement indicating value to reserve the deviation caused by the curvature characteristic, comparing the deviation with the calibration data, fitting to obtain a quadratic space curved surface through the deviation data caused by the curvature of the distance sensor array, and analyzing to obtain each curvature characteristic of the local space curved surface.
It is understood that, as shown in fig. 2, step S3 includes: and filtering the distance sensor deviation caused by the normal vector from the distance sensor measurement indicating value, keeping the deviation caused by the curvature characteristic, comparing the deviation with the calibration data, fitting to obtain a quadratic space curved surface through the deviation data caused by the curvature of the distance sensor array, and further analyzing each curvature characteristic of the local space curved surface.
Note that, compared to step S2, the normal vector feature of the curved surface focused on in step S2 is a first order term of the partially fitted curved surface of the workpiece, and the curvature feature of the curved surface focused on in step S3 is a second order term of the partially fitted curved surface of the workpiece. And further, fitting to obtain the curvature characteristic of the local curved surface of the workpiece, at the moment, after the correction process of the space vector, considering that the z axis of the measuring coordinate system of the compression ring is superposed with the normal vector of the corrected curved surface point to be measured, and after numerical analysis, the assumed error meets the precision requirement. At this time, after the measurement indication value of the distance sensor 2 array is corrected, the measurement indication value is only related to the curvature characteristic, calculation is carried out according to the data of the opposite distance sensors, curvature information of the fitting curved surface on three different sections can be obtained, and further, parameters and the curvature characteristic of the fitting curved surface are obtained through calculation.
In order to further understand the method for measuring the contact local curvature features according to the embodiments of the present application, the following detailed description is provided with reference to specific embodiments.
In connection with fig. 3 and 4, an embodiment of the present invention, when applied to the end of an automated processing machine, appears as an array of distance sensors in a compressed ring around the processing end. The processing mode of the processing mechanism applying the invention is as follows: firstly, the machining mechanism is gradually fed to enable the pressing ring to be tightly attached to and press the workpiece, so that the workpiece is prevented from moving and dislocating, and the workpiece is restrained from vibrating in the machining process. The machining mechanism can perform angle adjustment around an X rotating shaft and a Y rotating shaft in a rotating shaft of a measuring coordinate system shown in fig. 3 while providing feeding of the X, Y and Z axes, and the angle adjustment corresponds to the rotating shaft a and the rotating shaft C of the machining mechanism respectively, so that the Z axis of the machining coordinate system coincides with the normal vector of the machined position of the curved surface of the workpiece. Furthermore, the measuring system keeps the pressing state unchanged, the machining mechanism extends out of the inner ring surface of the pressing ring, and the curved surface of the machined workpiece is accurately machined along the z-axis direction.
The invention aims to improve the processing process to a certain extent and solve the measurement problem to a certain extent. Aiming at the measuring link in the processing process, the contact type local curvature measuring method comprises the following steps: s1, ensuring that the pressing ring is pressed on the workpiece and forms stable contact, and constructing a measurement coordinate system; s2, acquiring normal vectors and distance characteristics of the current workpiece under a measurement coordinate system by using a distance sensor array; and S3, calculating the current contact point position by using the normal vector, the distance information and the structural size of the compression ring, and further calculating the curvature characteristic of the current workpiece in the measurement coordinate system.
Taking the mechanism in the embodiment as an example, the specific implementation steps are demonstrated as follows:
the specific implementation steps of step S1 are:
s11, a pressing mechanism of the processing mechanism is used, so that the pressing ring surface 1 of the measuring system is in stable contact with the curved surface of the workpiece, and the curved surface of the workpiece and the pressing ring surface are considered to form a mathematical constraint relation. As shown in fig. 5, specifically, the mathematical constraint relationship is: and the highest point of the intersection line of the two cylindrical surfaces and the curved surface of the workpiece along the direction of the z axis is tangent to the xy plane of a measuring coordinate system.
Defining the radii of the inner ring surface and the outer ring surface of the compaction ring surface as R and R, and the spatial curved surface of the workpiece as z ═ f (x, y) in the measurement coordinate system, this constraint relationship can be expressed as:
s12, referring to the mechanism in the embodiment, taking the mechanism shown in fig. 4 as an example, referring to the end coordinate system forming form of the processing mechanism, a measurement coordinate system is established, and the distance sensor arrays 2.1 to 2.6 form three sets of corresponding relations as shown in fig. three, wherein the pairing mode is 2.1 for 2.4, 2.2 for 2.5, and 2.3 for 2.6. Wherein, the intersection line of the space plane where the measuring beam corresponding to 2.4 is positioned and the plane of the compression ring is defined as the x axis by 2.1, and the positive direction is defined as 2.1 pointing to 2.4. The plane of the compression ring is an xy plane, and the direction perpendicular to the x axis is defined as the y axis. Further, the z-axis is defined as being oriented perpendicular to the plane of the clamp ring, as defined by the three-dimensional coordinate system of the Cartesian coordinate system.
The specific implementation steps of step S2 are:
s21, obtaining the normal vector of the current workpiece under the measurement coordinate system by using the distance sensor array, wherein the specific implementation mode is that the indication value measured by the given distance sensor is calibrated to be verticalA distance of NH1～NH6(unit mm) corresponding to the measured readings of the distance sensors numbered 2.1 to 2.6 in FIG. 4, respectively, and the deviation angle theta of the normal vector at the ideal processing point on the processing curved surface along the x-axis directionx(in degrees) can be calculated by the formula:
wherein: rSThe radius of a distribution circle of measuring points of the distance sensor on an xy plane of a measuring coordinate system can be calculated by the design size of the clamp ring 1; α is the offset angle of the tilt mounting of the distance sensor, defined by the design dimensions of the end mechanism 3.
Furthermore, the deviation angle theta of the normal vector along the y-axis direction at the ideal processing point on the processing curved surfacey(in degrees) can be calculated by the formula:
and S22, acquiring the distance characteristic of the current workpiece by using the distance sensor array, and further judging the current curved surface type. In detail, in the processing process, especially the processing of the conventional thin plate workpiece in the industrial field, the curved surface of the plate mainly comprises the following components: a plane, a cylindrical surface or the like, a spherical surface or the like, a hyperboloid or the like, or the like. At least six points on the curved surface are measured by using the distance sensor array, and are compared with the plane data, so that the curved surface can be classified, and further, the position of each measuring point in the space is obtained. The position of the measuring point in space can be measured by
Is calculated to obtain wherein
Refers to the position vector of the measuring point in the measuring coordinate system space,
the finger distance sensor measures the corresponding position of the light spot at calibration time,
the finger distance sensor measures the space vector of the orientation.
The specific implementation steps of step S3 are:
and S31, calculating the current contact point position by using the normal vector, the distance information and the structural size of the compression ring. In detail, for the local characteristics of a complex curved surface, especially for a thin-wall curved surface workpiece applied in the industry, the high-order quantity coefficient in the mathematical description of the curved surface is small, and for the local curved surface, the fitting of a quadric surface can be carried out with high precision. For a quadratic fitting surface, when a normal vector of a compression ring surface, namely a z-axis of a measurement coordinate system, is coincident with a normal vector of a workpiece, the surface and the compression ring surface have the following conditions: firstly, two symmetrical points are in contact, and the device is suitable for paraboloids, cylindrical surfaces, hyperboloids, ellipsoids and the like; and the second is line contact, which is suitable for spherical surfaces. Further, in the presence of normal vector deviation, the contact condition is degraded to a single point contact. Theta after providing normal vector measurement datax，θyFurther, the position where the contact point exists can be calculated, and the position of the contact point is expressed as (Rcos α, Rsin α,0)T(concave, convex, hyperboloid, etc.) or (rcos α, rsin α,0)T(convex spherical, convex ellipsoidal, etc.).
And S32, finishing the deviation rectification of the normal vector by using the normal vector. In detail, the fitted quadric surface includes a second order quantity, a first order quantity and a zeroth order constant, for example, in the first case, the expression is as follows:
z＝f(x,y)＝ax2+bxy+cy2+tan(θx)x+tan(θy)y+h
the purpose of deviation rectification is to eliminate the influence of normal vector deflection on the curved surface, and simultaneously keep the constraint condition of the curved surface unchanged, at this time, after normal vector deviation rectification, the quadratic fitting function is degenerated into a function which is more convenient to calculate, and the form is as follows:
and S33, calculating the curvature characteristics of the surface of the workpiece which is pressed currently, and fitting to obtain a curved function. Specifically, the curvature characteristics referred to herein include principal radius of curvature, principal orientation of curvature, gaussian curvature, and mean curvature. Taking the arrangement situation of the distance sensors in the embodiment as an example, the point location data obtained by the current distance sensor is corrected and then is brought into the equation, and the curve coefficients a, b and c are further obtained by inverse solution. Furthermore, the distance of the actual processing position of the workpiece offset from the measuring coordinate system due to the workpiece curvature is obtained, i.e. the indication value of the actual processing position in the measuring coordinate system.
In conclusion, the application discloses a method for measuring contact type local curvature characteristics of a tail end mechanism suitable for drilling, spiral milling and automatic riveting machining, the principle is based on space solution of a curved surface, a measured curved surface is fitted by using a plurality of measuring points and curved surface constraint conditions, and finally, the curved surface curvature characteristics and normal vector characteristics are obtained for subsequent machining production, so that the machining precision is improved, and particularly the machining precision of a weak-rigidity thin-wall workpiece is improved. According to the contact type local curvature characteristic measuring method provided by the embodiment of the application, the local curvature characteristic of the curved surface workpiece can be analyzed when the processing equipment is in pressing contact, the normal vector deflection angle is provided, a quick and effective measuring method is provided for further normal vector adjustment and curvature compensation of subsequent processing equipment, and therefore the precision of the equipment is improved.
Next, a system for measuring a contact-type local curvature characteristic according to an embodiment of the present application will be described with reference to the drawings.
FIG. 6 is a block schematic diagram of a contact local curvature feature measurement system 10 according to an embodiment of the present application.
As shown in fig. 6, the contact local curvature feature measurement system 10 includes: a compression module 100, a measurement module 200 and a calculation module 300.
The pressing module 100 is used for contacting with a specific position to be processed of the workpiece by using a contact type pressing ring surface;
optionally, the compacting module 100 is specifically configured to: the pressing ring surface is controlled to be tightly attached to the surface of the workpiece under driving, so that the pressing ring surface is stably contacted with the curved surface of the workpiece; taking the measured data as a limiting condition, and taking the compaction ring surface as a reference to establish a measurement coordinate system; and constructing a vector mapping relation of the measurement data in a measurement coordinate system space according to the mounting calibration information of the distance sensor on the tail end mechanism.
The measuring module 200 is configured to acquire distance information of several points to be measured around the current workpiece torus by using the distance sensor array, and calculate an orientation feature of the current curved surface according to the distance information, where the orientation feature includes a local normal vector direction of a point location to be measured;
optionally, the measurement module 200 is specifically configured to: matching data of symmetrical distance sensor installation spaces in data measured by a distance sensor array for difference to obtain data points of sections of the curved surface to be measured in different distance sensor directions in the space; obtaining the skew relation of a plurality of sections of the curved surface relative to a measurement coordinate system according to the distribution characteristics of the distance sensors and the data difference values; and solving according to the deviation relation to obtain the data of the local normal vector of the position to be measured of the workpiece in the measuring coordinate system.
The calculation module 300 is configured to calculate curvature characteristics of the workpiece curved surface corresponding to the current compression ring surface by using the normal vector, the distance sensor distribution characteristics, and the measurement indication, where the curvature characteristics include a principal curvature radius, a principal curvature orientation, an average curvature, and a gaussian curvature, so as to fit the local curved surface by using a quadric surface.
Optionally, the computing module 300 is specifically configured to: and filtering the distance sensor deviation caused by the normal vector from the distance sensor measurement indicating value to reserve the deviation caused by the curvature characteristic, comparing the deviation with the calibration data, fitting to obtain a quadratic space curved surface through the deviation data caused by the curvature of the distance sensor array, and analyzing to obtain each curvature characteristic of the local space curved surface.
That is, as shown in fig. 6 and 7 in combination, the contact local curvature feature measurement system 10 includes: a compression module 100; a measurement module 200 and a calculation module 300.
The pressing module 100 is in contact with the surface of the workpiece by using a smooth rigid ring surface, and provides calibration information and a measurement coordinate system reference; the measuring module 200 is used for acquiring data of a plurality of measuring point positions with specific sizes on the surface of the workpiece; and the calculating module 300 is configured to calculate the parameters of the fitted surface function near the to-be-processed position, and further process the parameters to obtain the curvature characteristics.
Further, in an embodiment of the present invention, the compression module 100 includes: the smooth circular ring surface can protect the workpiece and provide stable compaction capability, and surface damage of some workpieces which are not wear-resistant is reduced as much as possible; providing stable compaction to prevent the workpiece from displacement or fluttering in the subsequent process; meanwhile, the center of the circular ring surface of the compaction module is regarded as the zero point of a measuring coordinate system, and a coordinate system is further established and is also the zero point of a processing coordinate system after the measurement is finished.
Further, in one embodiment of the present invention, the measurement module 200 includes: the fixed hardware module 201 specially provided with the distance sensor array uses a laser distance sensor in a non-contact measurement mode in the embodiment, and a contact type length meter also meets the requirement; the distance sensor is used for symmetrically measuring distance data of a plurality of specific measuring points on the surface of the workpiece in a specific form, and the measured data is compared with the calibration data in the distance sensor reading conversion module 202 to obtain the spatial position under the measuring coordinate system.
Further, in one embodiment of the present invention, the calculation module includes: the normal vector processing unit 301 is configured to perform plane fitting on data of the distance sensor array, obtain a normal vector deflection amount, and obtain a spatial solution of a normal vector in the measurement coordinate system; the normal vector deviation correcting unit 302 is configured to eliminate an indication deviation of the distance sensor caused by the normal vector deviation to obtain a corrected local curved surface feature that only includes a function quadratic term; and the curvature extraction unit 303 is configured to extract curvature characteristics from the result of the normal vector rectification unit, and further calculate to obtain each parameter of the curved surface for subsequent compensation.
It should be noted that the foregoing explanation of the embodiment of the method for measuring a contact local curvature feature is also applicable to the system for measuring a contact local curvature feature of the embodiment, and is not repeated here.
According to the contact type measuring system for the local curvature characteristics, the system is small in structure and suitable for automatic processing equipment of complex curved surface workpieces and narrow operation spaces, the processing coverage rate of the automatic processing equipment in the processing process is improved, the local curvature characteristics of the curved surface workpieces can be analyzed when the processing equipment is in pressing contact, a normal vector deflection angle is provided, a quick and effective measuring method is provided for further normal vector adjustment and curvature compensation of subsequent processing equipment, and therefore the precision of the equipment is improved.
Fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present application. The electronic device may include:
a memory 1201, a processor 1202, and a computer program stored on the memory 1201 and executable on the processor 1202.
The processor 1202, when executing the program, implements the method for measuring contact local curvature characteristics provided in the above-described embodiments.
Further, the electronic device further includes:
a communication interface 1203 for communication between the memory 1201 and the processor 1202.
A memory 1201 for storing computer programs executable on the processor 1202.
The memory 1201 may comprise high-speed RAM memory, and may also include non-volatile memory (non-volatile memory), such as at least one disk memory.
If the memory 1201, the processor 1202 and the communication interface 1203 are implemented independently, the communication interface 1203, the memory 1201 and the processor 1202 may be connected to each other through a bus and perform communication with each other. The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown in FIG. 8, but this is not intended to represent only one bus or type of bus.
Optionally, in a specific implementation, if the memory 1201, the processor 1202, and the communication interface 1203 are integrated on a chip, the memory 1201, the processor 1202, and the communication interface 1203 may complete mutual communication through an internal interface.
The present embodiment also provides a computer-readable storage medium on which a computer program is stored, wherein the program is implemented, when executed by a processor, to implement the method for measuring a contact local curvature characteristic as described above.
In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or N embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "N" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more N executable instructions for implementing steps of a custom logic function or process, and alternate implementations are included within the scope of the preferred embodiment of the present application in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of implementing the embodiments of the present application.
The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or N wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.
Claims (6)
1. A method for measuring a contact local curvature feature, comprising the steps of:
the contact-type pressing ring surface is contacted with a specific position to be processed of the workpiece, wherein the contact-type pressing ring surface is contacted with the specific position to be processed of the workpiece, and the contact-type pressing ring surface comprises the following steps: controlling the pressing ring surface to be tightly attached to the surface of the workpiece under driving so that the pressing ring surface is stably contacted with the curved surface of the workpiece; taking the measured data as a limiting condition, and taking the compaction ring surface as a reference to establish a measurement coordinate system; constructing a vector mapping relation of measurement data in a measurement coordinate system space according to the installation calibration information of the distance sensor on the tail end mechanism;
acquiring distance information of a plurality of points to be measured around the current workpiece ring surface by using a distance sensor array, and calculating orientation characteristics of the current curved surface according to the distance information, wherein the orientation characteristics comprise local normal vector directions of the points to be measured;
calculating curvature characteristics of the workpiece curved surface corresponding to the current compression ring surface by using the normal vector, the distribution characteristics of the distance sensors and the measurement indication values, wherein the curvature characteristics comprise a main curvature radius, a main curvature orientation, an average curvature and a Gaussian curvature, and the curvature characteristics of the workpiece curved surface corresponding to the current compression ring surface by using the normal vector, the distribution characteristics of the distance sensors and the measurement indication values comprise: and filtering the distance sensor deviation caused by the normal vector from the distance sensor measurement indicating value to reserve the deviation caused by the curvature characteristic, comparing the deviation with the calibration data, fitting to obtain a quadratic space curved surface through the deviation data caused by the curvature of the distance sensor array, and analyzing to obtain each curvature characteristic of the local space curved surface.
2. The method of claim 1, wherein the obtaining distance information of several points to be measured around the current workpiece ring surface by using the distance sensor array and calculating the orientation feature of the current curved surface according to the distance information comprises:
matching data of symmetrical distance sensor installation spaces in data measured by a distance sensor array for difference to obtain data points of sections of the curved surface to be measured in different distance sensor directions in the space;
obtaining the skew relation of a plurality of sections of the curved surface relative to a measurement coordinate system according to the distribution characteristics of the distance sensors and the data difference values;
and solving according to the deflection relation to obtain the data of the local normal vector of the position to be measured of the workpiece in the measuring coordinate system.
3. A contact local curvature feature measurement system, comprising:
the pressing module is used for pressing the annular surface to be contacted with a specific position to be processed of the workpiece by utilizing a contact mode, wherein the pressing module is specifically used for: controlling the pressing ring surface to be tightly attached to the surface of the workpiece under driving so that the pressing ring surface is stably contacted with the curved surface of the workpiece; taking the measured data as a limiting condition, and taking the compaction ring surface as a reference to establish a measurement coordinate system; constructing a vector mapping relation of measurement data in a measurement coordinate system space according to the installation calibration information of the distance sensor on the tail end mechanism;
the measuring module is used for acquiring distance information of a plurality of points to be measured around the current workpiece ring surface by using the distance sensor array and calculating the orientation characteristic of the current curved surface according to the distance information, wherein the orientation characteristic comprises the local normal vector direction of the point to be measured;
the calculation module is used for calculating the curvature characteristics of the workpiece curved surface corresponding to the current compression ring surface by using the normal vector, the distribution characteristics of the distance sensors and the measurement indicating values, wherein the curvature characteristics comprise a main curvature radius, a main curvature orientation, an average curvature and a Gaussian curvature, and the calculation module is specifically used for: and filtering the distance sensor deviation caused by the normal vector from the distance sensor measurement indicating value to reserve the deviation caused by the curvature characteristic, comparing the deviation with the calibration data, fitting to obtain a quadratic space curved surface through the deviation data caused by the curvature of the distance sensor array, and analyzing to obtain each curvature characteristic of the local space curved surface.
4. The system of claim 3, wherein the measurement module is specifically configured to:
matching data of symmetrical distance sensor installation spaces in data measured by a distance sensor array for difference to obtain data points of sections of the curved surface to be measured in different distance sensor directions in the space;
obtaining the skew relation of a plurality of sections of the curved surface relative to a measurement coordinate system according to the distribution characteristics of the distance sensors and the data difference values;
and solving according to the deflection relation to obtain the data of the local normal vector of the position to be measured of the workpiece in the measuring coordinate system.
5. An electronic device, comprising: a memory, a processor and a computer program stored on the memory and executable on the processor, the processor executing the program to implement the method of measuring a contact local curvature characteristic of any one of claims 1-2.
6. A computer-readable storage medium, on which a computer program is stored, the program being executable by a processor for implementing the method of contact local curvature feature measurement according to any of claims 1-2.
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