CN114117315B - Straightness estimation method and straightness estimation system based on minimum inclusion area - Google Patents
Straightness estimation method and straightness estimation system based on minimum inclusion area Download PDFInfo
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Abstract
The invention discloses a measured part object straightness estimation method based on a minimum containment area, which comprises the following steps: s1, acquiring a measured part object measurement sampling point set of a straightness measuring instrument and converting the measured part object measurement sampling point set into an ordered evaluation point set; s2, calculating a left envelope point set and a right envelope point set according to the ordered evaluation point set; s3, constructing a plurality of left envelope straight lines according to a left envelope point set, and calculating the distance from a point in a right envelope point set to the left envelope straight line for each left envelope straight line, wherein the maximum value of the distance is the inclusion region value of the left envelope straight line; s4, constructing a plurality of right envelope straight lines according to the right envelope points, and calculating the distance from a point in a right envelope point set to the right envelope straight lines for each right envelope straight line, wherein the maximum value of the distance is the inclusion region value of the right envelope straight lines; s5, taking the minimum inclusion area value as the minimum inclusion area, and adopting the normal distance between two minimum area linesStraightness error as a measured part object.
Description
Technical Field
The invention relates to the field of precision measurement, in particular to a method for calculating a straightness minimum inclusion area.
Background
The straightness is one of basic geometric elements representing the shape of a part, and three in-plane straightness error assessment methods are respectively a two-end point connection method, a least square method and a least inclusion region method in the national standard GB/T11336-2004 straightness error detection. The accuracy of the evaluation result of the minimum inclusion region method is higher than that of a two-end point connection method and a least square method which are widely applied, but only one high-low-high or low-high-low judgment method is given in the standard, no instructive algorithm implementation is given, and the practical application is limited.
Existing in-plane straightness error assessment mainThe straightness error is obtained by a numerical calculation method, and geometric characteristics of in-plane straightness error assessment are ignored to a certain extent. In addition, the time complexity of the existing minimum inclusion region algorithm is greater than that of O (N 2 ) It is not suitable to handle large data point sets.
Disclosure of Invention
The invention mainly aims to provide a high-efficiency reliable straightness evaluation method without model calculation errors.
The technical scheme adopted by the invention is as follows:
the straightness estimation method based on the minimum inclusion area comprises the following steps:
s1, acquiring a measurement sampling point set of a straightness measuring instrument and converting the measurement sampling point set into an ordered evaluation point set;
s2, calculating a left envelope point set and a right envelope point set according to the ordered evaluation point set;
s3, constructing a plurality of left envelope straight lines according to a left envelope point set, and calculating the distance from a point in a right envelope point set to the left envelope straight line for each left envelope straight line, wherein the maximum value of the distance is the inclusion region value of the left envelope straight line;
s4, constructing a plurality of right envelope straight lines according to the right envelope points, and calculating the distance from a point in a right envelope point set to the right envelope straight lines for each right envelope straight line, wherein the maximum value of the distance is the inclusion region value of the right envelope straight lines;
s5, the smallest containing region value in the containing region values of the left containing straight line and the right containing straight line is the smallest containing region, and the enveloping straight line corresponding to the smallest containing region is the smallest region line of the straightness.
According to the technical scheme, the ordered evaluation point set is a set of straightness measurement sampling points ordered along the straightness measurement direction.
In connection with the above technical solution, the calculating the left envelope point set in step S2 specifically includes:
taking a head end point of the ordered evaluation point set as an initial left envelope point, taking the initial left envelope point as a starting point, pointing to a point positioned behind the initial left envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new left envelope point; and searching the new left envelope point by taking the new left envelope point as an initial left envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the left evaluation point set.
In connection with the above technical solution, the calculating the right envelope point set in step S2 specifically includes:
taking a head end point of the ordered evaluation point set as an initial right envelope point, taking the initial right envelope point as a starting point, pointing to a point positioned behind the initial right envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new right envelope point; and searching the new right envelope point by taking the new right envelope point as an initial right envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the right envelope point set.
By adopting the technical scheme, the vector angle of the vector is obtained by the following method
Wherein x is k ，y k As the end point coordinates of the vector, x 1 ，y 1 Is the initial point coordinate of the vector, atan2 is the calculated vector (-pi, pi)]Arctangent function of azimuth angle in range.
In the above technical solution, the method of constructing a plurality of left envelope straight lines in step S3 is to construct straight lines according to two adjacent points in the left envelope point set.
In the above technical solution, the method for constructing a plurality of right envelope straight lines in step S4 is to construct straight lines according to two adjacent points in the right envelope point set.
The invention also provides a straightness estimation system based on the minimum inclusion area, which comprises:
the point set acquisition module is used for acquiring a measurement sampling point set of the straightness measuring instrument and converting the measurement sampling point set into an ordered evaluation point set;
the left envelope point set and right envelope point set calculation module is used for calculating a left envelope point set and a right envelope point set according to the ordered evaluation point set;
the left envelope straight line construction module is used for constructing a plurality of left envelope straight lines according to a left envelope point set, and calculating the distance from a point in a right envelope point set to the left envelope straight line for each left envelope straight line, wherein the maximum value of the distance is the inclusion area value of the left envelope straight line;
the right envelope straight line construction module is used for constructing a plurality of right envelope straight lines according to the right envelope points, and calculating the distance from a point in a right envelope point set to the right envelope straight line for each right envelope straight line, wherein the maximum value of the distance is the inclusion region value of the right envelope straight line;
the minimum region line determining module is used for taking the minimum inclusion region value in the inclusion region value of the left inclusion straight line and the inclusion region value of the right inclusion straight line as the minimum inclusion region, and the inclusion straight line corresponding to the minimum inclusion region is the minimum region line of the straightness.
With the above technical solution, the left and right envelope point set calculation module is specifically configured to:
taking a head end point of the ordered evaluation point set as an initial left envelope point, taking the initial left envelope point as a starting point, pointing to a point positioned behind the initial left envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new left envelope point; searching the new left envelope point by taking the new left envelope point as an initial left envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the left evaluation point set;
taking a head end point of the ordered evaluation point set as an initial right envelope point, taking the initial right envelope point as a starting point, pointing to a point positioned behind the initial right envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new right envelope point; and searching the new right envelope point by taking the new right envelope point as an initial right envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the right envelope point set.
The present invention also provides a computer storage medium executable by a processor, having stored therein a computer program for performing the minimum inclusion region based straightness estimation method according to any one of claims 1-7.
The invention has the beneficial effects that: the invention provides a quick calculation method based on the minimum straightness containing area of an envelope vector from the geometrical characteristics of the in-plane straightness error assessment, which can be realized by a method with high efficiency, reliability and no model calculation error and is suitable for processing a large data point set.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a flow chart of a method for estimating straightness based on a minimum inclusion region according to an embodiment of the present invention;
FIG. 2 is a minimum area envelope model based on envelope points according to an embodiment of the invention;
FIG. 3 is a schematic diagram of the output result of the minimum containment region algorithm according to an embodiment of the present invention;
FIG. 4 is a graph showing the relationship between the evaluation point set size (1 ten thousand points to 500 ten thousand points) and the algorithm time consumption and the number of envelope points according to the embodiment of the invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
As shown in fig. 1, the straightness estimation method based on the minimum inclusion area according to the embodiment of the invention includes the following steps:
s1, acquiring a measurement sampling point set of a straightness measuring instrument and converting the measurement sampling point set into an ordered evaluation point set;
s2, calculating a left envelope point set and a right envelope point set according to the ordered evaluation point set;
s3, constructing a plurality of left envelope straight lines according to a left envelope point set, and calculating the distance from a point in a right envelope point set to the left envelope straight line for each left envelope straight line, wherein the maximum value of the distance is the inclusion region value of the left envelope straight line;
s4, constructing a plurality of right envelope straight lines according to the right envelope points, and calculating the distance from a point in a right envelope point set to the right envelope straight lines for each right envelope straight line, wherein the maximum value of the distance is the inclusion region value of the right envelope straight lines;
s5, the smallest containing region value in the containing region values of the left containing straight line and the right containing straight line is the smallest containing region, and the enveloping straight line corresponding to the smallest containing region is the smallest region line of the straightness.
The ordered evaluation point set is a set of straightness measurement sampling points ordered along the straightness measurement direction.
The calculating the left envelope point set in step S2 specifically includes:
taking a head end point of the ordered evaluation point set as an initial left envelope point, taking the initial left envelope point as a starting point, pointing to a point positioned behind the initial left envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new left envelope point; and searching the new left envelope point by taking the new left envelope point as an initial left envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the left evaluation point set.
The calculating the right envelope point set in step S2 specifically includes:
taking a head end point of the ordered evaluation point set as an initial right envelope point, taking the initial right envelope point as a starting point, pointing to a point positioned behind the initial right envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new right envelope point; and searching the new right envelope point by taking the new right envelope point as an initial right envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the right envelope point set.
The method for constructing the plurality of left envelope straight lines in the step S3 is to construct straight lines according to two adjacent points in the left envelope point set.
The method for constructing the plurality of right envelope straight lines in the step S4 is to construct straight lines according to two adjacent points in the right envelope point set.
The definition of the straightness minimum inclusion area given in the straightness standard is a geometric description, namely the straightness minimum inclusion area refers to an area which is included in an actual straight line and has two parallel straight lines with the minimum width. The two parallel ideal straight lines that make up the minimum straightness containment region are called the minimum area lines. The invention gives the envelope model of the minimum inclusion area of the straightness in the plane from the geometrical point of view.
For an evaluation point set, fig. 2 shows the positional relationship of the point sets, an envelope line segment formed by sequentially connecting envelope points of the evaluation point set clockwise or counterclockwise forms a closed envelope region, and all points of the evaluation point set fall inside the envelope region or on the envelope line segment, and one of the envelope line segments and one of the envelope points must fall on the minimum region line.
The envelope model has a definite geometric meaning and no approximation exists. The key of the model solving is the determination of the envelope points in the evaluation point set, and the judgment principle of the envelope points in the evaluation point set is as follows according to the definition of the envelope model.
To evaluate any envelope point E of a point set n Constructing a vector for the vertex to the rest of the set of evaluation points if point E n And point E n+1 、E n-1 The sector formed (sector angle less than 180 °), i.e. as in fig. 2 +.e n+1 E n E n-1 A sector area covering all the points in the evaluation point setReferred to as envelope vector, point E n+1 、E n-1 Also the envelope points.
In the embodiment of the present invention, the algorithm for searching the envelope point in step S2 is mainly implemented by the following method:
for the measurement of the straightness in a plane, basically, unidirectional measurement is performed along the measurement direction, and from the measurement method, the obtained measurement point set is an ordered point set W along the measurement direction, namely:
wherein x is k ，y k Is the kth point P k Is defined by the coordinates of (a).
If the point set to be evaluated is not an ordered point set along the measurement direction, the point set needs to be ordered along the measurement direction first. For an ordered set of points, the initial and final points must be envelope points, and also the starting and ending points of the set of evaluation points for envelope point searching. The algorithm for searching the envelope points is implemented as follows, taking the head point of the evaluation point set as the starting point.
1) To evaluate the head point P of the point set 1 For initial envelope point, constructing head end point P 1 Vectors pointing to other points of the set of evaluation pointsAnd calculates the vector angle θ of the vector using atan2 k (-π＜θ k ＜π]The method comprises the following steps:
2) A left envelope point set L is constructed. First, a left envelope point set is initialized with the head point of the evaluation point set, i.e., l= { P 1 -end point P of vector corresponding to maximum vector angle constructed in step 1 L1 For a new left envelope point, and add the left envelope point set, i.e., l= { P 1 ，P L1 }. With P L1 Based on, build with P L1 Pointing to evaluation Point set P L1 Vector of subsequent points of the points, calculating vector angle, and point P corresponding to maximum vector angle Li For a new left envelope point, add to the left envelope point set, i.e. l= { P 1 ，P L1 ，P Li Continuously repeating until the end point P of the point set is evaluated N Adding the left envelope point set to obtain a left envelope point set L= { P 1 ，P L1 ，…，P N }。
3) A right set of envelope points R is constructed. First, a right envelope point set is initialized with the head point of the evaluation point set, i.e., r= { P 1 }，The end point P of the vector corresponding to the minimum vector angle constructed in the step 1 R1 For a new right envelope point, and add the right envelope point set, i.e., r= { P 1 ，P R1 }. With P R1 Based on, build with P R1 Pointing to evaluation Point set P R1 Vector of subsequent points of the points, calculating vector angle, and point P corresponding to minimum vector angle Ri For a new right envelope point, add to the right envelope point set, i.e. r= { P 1 ，P R1 ，P Ri Continuously repeating until the end point P of the point set is evaluated N Adding a left envelope point set, i.e. r= { P 1 ，P R1 ，…，P N }。
The simple flow of the envelope point set search is shown in fig. 3, and for each envelope pole, only a vector needs to be constructed for the subsequent evaluation points, so that the worst time complexity of the algorithm is O (N-1)/2), i.e. all the evaluation points are envelope points. In practical situations, the number Q of the envelope points of an evaluation point set is far smaller than the size N of the evaluation point set, so that the time complexity is about O (N), and the number Q of the evaluation point sets is approximately linear.
The method can also be used for searching the envelope points by constructing a straight line by using the head point and the tail point of the ordered point set, dividing the ordered point set into a straight line left part point and a straight line right part point, respectively calculating a left envelope point set for the left part point and a right envelope point set for the right part point, and further improving the calculation efficiency.
In step S3, an envelope straight line is constructed specifically through envelope points, and a left envelope point set l= { P 1 ，P L1 ，…，P N Sum right envelope point set r= { P 1 ，P R1 ，…，P N Based on the two adjacent points in the envelope point set, constructing an envelope straight line, traversing the envelope point set and then solving all the envelope straight lines. The invention adopts an inclined section type parameter set (k represents slope, b represents intercept) for constructing an envelope straight line, and respectively carries out envelope straight line parameter set calculation on a left envelope point set and a right envelope point set, wherein the calculation results are respectively marked as E L ＝{(k L1 ，b L1 )；…；(k Lm ，b Lm )}，E R ＝{(k R1 ，b R1 )；…；(k Rn ，b Rn )}。
In step S5, the value of the inclusion area of each envelope line is calculated based mainly on the obtained diagonal parameter set E of the envelope line L ＝{(k L1 ，b L1 )；…；(k Lm ，b Lm ) Sum E R ＝{(k R1 ，b R1 )；…；(k Rn ，b Rn ) Calculating the minimum area value of each envelope straight line by combining the envelope point sets, wherein E L Combined with the right envelope point set R, E R By combining the left envelope point set L, the calculated amount can be greatly reduced. The minimum area value of each envelope straight line is the maximum distance from the corresponding envelope point set to the distance of the envelope straight line, and then a containing area value set D= { D corresponding to all the envelope straight lines is constructed 1 ，…，d M Sum corresponding envelope pole set r= { P R1 ，…，R RM }. The minimum containment area value is calculated by using a point-to-line distance formula.
Where k and b are the slope and intercept of the envelope line, respectively, (x) E 、y E ) Is the coordinates of the envelope point.
When the minimum inclusion region is calculated, the value D= { D is calculated from the inclusion region value set 1 ，…，d M Finding the smallest containing region value d min And according to d min At a position in the set D, a parameter (k) corresponding to the envelope straight line is obtained min ，b min ) Envelope pole P min Straight line L determined by envelope straight line parameter 1 ：y＝k min ·x+b min And over-envelope pole P min At k min Straight line L with slope 2 ＝k min ·(x-x min )+y min I.e. the minimum area line, straight line L 1 ，L 2 The distance between the two lines is the minimum containment area, and the normal distance d between the two minimum area lines is adopted in the patent min As a straightness error.
In the specific implementation, the envelope straight line parameter set can be constructed by adopting the general equation coefficient of the straight line, and the minimum inclusion area is calculated.
Fig. 3 is a relative position of an example point set, where fig. 3 (a) gives a graphical representation of the result of the envelope point set search, and fig. 3 (b) shows the envelope line segment constructed from the envelope points, and the resulting minimum area line and straightness error.
The straightness estimation system based on the minimum inclusion area comprises:
the point set acquisition module is used for acquiring a measurement sampling point set of the straightness measuring instrument and converting the measurement sampling point set into an ordered evaluation point set;
the left envelope point set and right envelope point set calculation module is used for calculating a left envelope point set and a right envelope point set according to the ordered evaluation point set;
the left envelope straight line construction module is used for constructing a plurality of left envelope straight lines according to a left envelope point set, and calculating the distance from a point in a right envelope point set to the left envelope straight line for each left envelope straight line, wherein the maximum value of the distance is the inclusion area value of the left envelope straight line;
the right envelope straight line construction module is used for constructing a plurality of right envelope straight lines according to the right envelope points, and calculating the distance from a point in a right envelope point set to the right envelope straight line for each right envelope straight line, wherein the maximum value of the distance is the inclusion region value of the right envelope straight line;
the minimum region line determining module is used for taking the minimum inclusion region value in the inclusion region value of the left inclusion straight line and the inclusion region value of the right inclusion straight line as the minimum inclusion region, and the inclusion straight line corresponding to the minimum inclusion region is the minimum region line of the straightness.
Further, the left and right envelope point set calculation module is specifically configured to:
taking a head end point of the ordered evaluation point set as an initial left envelope point, taking the initial left envelope point as a starting point, pointing to a point positioned behind the initial left envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new left envelope point; searching the new left envelope point by taking the new left envelope point as an initial left envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the left evaluation point set;
taking a head end point of the ordered evaluation point set as an initial right envelope point, taking the initial right envelope point as a starting point, pointing to a point positioned behind the initial right envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new right envelope point; and searching the new right envelope point by taking the new right envelope point as an initial right envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the right envelope point set.
The modules of the straightness estimation system based on the minimum inclusion area are mainly used for implementing the method embodiments, and are not described in detail herein.
The present application also provides a computer readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card memory (e.g., SD or DX memory, etc.), a Random Access Memory (RAM), a Static Random Access Memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, a server, an App application store, etc., having stored thereon a computer program that when executed by a processor performs a corresponding function. The computer readable storage medium of the present embodiment is used for storing a linearity estimation system program based on a minimum inclusion region, which when executed by a processor implements the linearity estimation method based on a minimum inclusion region of the method embodiment.
With the improvement of the speed and the precision of the measuring equipment, the straightness measurement based on the scanning mode can generate a large amount of measurement data, so that an efficient straightness error assessment algorithm is required. In practical application, the number of the envelope points of each measuring point set has a great relation with the surface of the measured object, and for the same measured object, even if the number of the measuring points is increased, the number of the envelope points is basically unchanged. The model and the algorithm provided by the patent adopt a unidirectional searching method based on backward envelop point position, the average time complexity is O (N) level, and the model and the algorithm are particularly suitable for calculating the minimum area value of a large data point set.
In order to verify the efficiency of the algorithm, time-consuming experiments for analysis algorithms were designed. The detailed information of the experimental design is as follows:
1) The program runs in a hardware environment. TPN-C125 portable computer, the hardware is configured as Intel (R) Core (TM) i7-5500U CPU@2.40GHz,8.00GB memory;
2) The program runs a software environment. Windows 8.1-64 bit operating system, programming software is Matlab R2015b;
3) The x coordinate of the evaluation point set is 0 to 1000 (can be equivalent to the length of the measured object), N measuring points are taken at equal intervals, N random numbers meeting normal distribution, which are expected to be 0 and have a standard deviation of 1 (0.1% of the maximum value of the x coordinate) are generated by using random as measuring data, namely the y coordinate of the evaluation point set;
4) The number of the data points N is from 1 ten thousand points to 500 ten thousand points, the steps are 1 ten thousand points, 20 times of calculation are carried out for each point set, the time-consuming average value of the algorithm is obtained, meanwhile, the number of the envelope points in the envelope point set is calculated, and the influence of special distribution of the data in the point set on the algorithm can be eliminated through multiple times of average.
Fig. 4 is a graph showing the relationship between the size of the evaluation point set (1 ten thousand to 500 ten thousand) and the time consumption of the algorithm and the number of the envelope points, and as can be seen from fig. 4, the time consumption of the algorithm and the number of the evaluation point sets are approximately linear, and the data sets of millions of points can be calculated within 10 seconds. As can be seen from fig. 4, the number of the envelope points of the point set to be evaluated does not substantially change with the number of points of the point set to be evaluated, and the algorithm of the patent is based on backward unidirectional search of the positions of the envelope points, and the time complexity of the algorithm is verified to be approximately O (N).
In conclusion, the patent provides a model of the minimum inclusion area of the in-plane straightness based on the envelope point and an envelope point judging principle according to the definition of the minimum inclusion area according to the geometric characteristics of the in-plane straightness error assessment, and realizes the error-free in-plane minimum area straightness error assessment. The model is simple and visual, and the algorithm is efficient to realize, and has the following characteristics.
1) Based on the straightness minimum inclusion area algorithm of the model, the algorithm time complexity is in the O (N) level, and the algorithm is simple, accurate and efficient, is convenient to realize by using common programming languages such as C/C++, and can be rapidly integrated into the existing equipment;
(2) In practical application, it is not necessary to calculate vector angle of vector by using atan2, only according to y k -y 1 、x k -x 1 The sign and the ratio of the number of the symbols are judged, so that the calculated amount can be effectively reduced;
(3) The algorithm of the patent adopts a unidirectional searching method, adapts to a unidirectional measuring principle, can update the calculated parameters immediately every time new data is added, can complete searching of the envelope points of the measuring point set after the measurement is completed, and realizes real-time processing of the data.
It will be understood that modifications and variations will be apparent to those skilled in the art from the foregoing description, and it is intended that all such modifications and variations be included within the scope of the following claims.
Claims (10)
1. The measured part object straightness estimation method based on the minimum containment area is characterized by comprising the following steps of:
s1, acquiring a measured part object measurement sampling point set of a straightness measuring instrument and converting the measured part object measurement sampling point set into an ordered evaluation point set;
s2, calculating a left envelope point set and a right envelope point set according to the ordered evaluation point set;
s3, constructing a plurality of left envelope straight lines according to a left envelope point set, and calculating the distance from a point in a right envelope point set to the left envelope straight line for each left envelope straight line, wherein the maximum value of the distance is the inclusion region value of the left envelope straight line;
s4, constructing a plurality of right envelope straight lines according to the right envelope points, and calculating the distance from a point in a right envelope point set to the right envelope straight lines for each right envelope straight line, wherein the maximum value of the distance is the inclusion region value of the right envelope straight lines;
s5, the smallest inclusion region value in the inclusion region value of the left inclusion straight line and the inclusion region value of the right inclusion straight line is the smallest inclusion region, and the inclusion straight line corresponding to the smallest inclusion region is the smallest region of the straightnessA line using the normal distance between two minimum area linesStraightness error as a measured part object.
2. The method for estimating the straightness of a measured part object based on a minimum containment area according to claim 1, wherein the ordered evaluation point set is a set of straightness measurement sampling points ordered along a straightness measurement direction.
3. The method for estimating the straightness of a measured part object based on a minimum inclusion area according to claim 1, wherein the calculating of the left envelope point set in step S2 specifically includes:
taking a head end point of the ordered evaluation point set as an initial left envelope point, taking the initial left envelope point as a starting point, pointing to a point positioned behind the initial left envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new left envelope point; and searching the new left envelope point by taking the new left envelope point as an initial left envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the left evaluation point set.
4. The method for estimating the straightness of a measured part object based on a minimum containment area according to claim 1, wherein the calculating the right envelope point set in step S2 specifically includes:
taking a head end point of the ordered evaluation point set as an initial right envelope point, taking the initial right envelope point as a starting point, pointing to a point positioned behind the initial right envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new right envelope point; and searching the new right envelope point by taking the new right envelope point as an initial right envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the right envelope point set.
5. The method for estimating the straightness of a measured part object based on a minimum containment area according to claim 3 or 4, wherein the vector angle of the vector is obtained by
Wherein the method comprises the steps of，/>For the end point coordinates of the vector, +.>，/>For the head point coordinates of the vector,/>To calculate vectorsArctangent function of azimuth angle in range.
6. The method for estimating the straightness of a measured part object based on a minimum inclusion area according to claim 1, wherein the method for constructing a plurality of left envelope straight lines in the step S3 is to construct straight lines according to two adjacent points in a left envelope point set.
7. The method for estimating the straightness of a measured part object based on a minimum inclusion area according to claim 1, wherein the method for constructing a plurality of right envelope straight lines in the step S4 is to construct straight lines according to two adjacent points in a right envelope point set.
8. A measured part object straightness estimation system based on a minimum containment area, comprising:
the point set acquisition module is used for acquiring a measured sampling point set of a measured part object of the straightness measuring instrument and converting the measured sampling point set into an ordered evaluation point set;
the left envelope point set and right envelope point set calculation module is used for calculating a left envelope point set and a right envelope point set according to the ordered evaluation point set;
the left envelope straight line construction module is used for constructing a plurality of left envelope straight lines according to a left envelope point set, and calculating the distance from a point in a right envelope point set to the left envelope straight line for each left envelope straight line, wherein the maximum value of the distance is the inclusion area value of the left envelope straight line;
the right envelope straight line construction module is used for constructing a plurality of right envelope straight lines according to the right envelope points, and calculating the distance from a point in a right envelope point set to the right envelope straight line for each right envelope straight line, wherein the maximum value of the distance is the inclusion region value of the right envelope straight line;
the minimum region line determining module is used for taking the minimum inclusion region value in the inclusion region value of the left inclusion straight line and the inclusion region value of the right inclusion straight line as the minimum inclusion region, wherein the inclusion straight line corresponding to the minimum inclusion region is the minimum region line of the straightness, and the normal distance between the two minimum region lines is adoptedStraightness error as a measured part object.
9. The minimum containment region-based measured part object straightness estimation system according to claim 8, wherein the left and right envelope point set calculation module is specifically configured to:
taking a head end point of the ordered evaluation point set as an initial left envelope point, taking the initial left envelope point as a starting point, pointing to a point positioned behind the initial left envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new left envelope point; searching the new left envelope point by taking the new left envelope point as an initial left envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the left evaluation point set;
taking a head end point of the ordered evaluation point set as an initial right envelope point, taking the initial right envelope point as a starting point, pointing to a point positioned behind the initial right envelope point in the ordered evaluation point set, and constructing a vector set, wherein an end point of a vector with the minimum vector angle in the vector set is a new right envelope point; and searching the new right envelope point by taking the new right envelope point as an initial right envelope point until the end point of the ordered evaluation point set is reached, and completing the construction of the right envelope point set.
10. A computer storage medium, which is executable by a processor, in which a computer program is stored, the computer program executing the measured part object straightness estimation method based on the minimum containment area according to any one of claims 1 to 7.
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