阅读说明：本技术 一种基于弯制点角距比和的正畸弓丝变半径圆域划分方法 (Orthodontic arch wire variable-radius circular domain dividing method based on bending point-angular distance ratio sum ) 是由 姜金刚 吴殿昊 郭亚峰 张永德 闵兆伟 曾阳 于 2020-06-01 设计创作，主要内容包括：本发明公开了一种基于弯制点角距比和的正畸弓丝变半径圆域划分方法,它涉及正畸弓丝弯制技术领域,本发明针对弯制点密集程度较小的一类正畸弓丝曲线,基于正畸弓丝曲线弯制点信息集、弯制点的机器人弯制信息集,结合机器人弯制正畸弓丝的运动特点,建立一种基于弯制点角距比和的正畸弓丝变半径圆域划分方法。技术要点为：将正畸弓丝曲线T转换为平面曲线T′；圆域限制参数的设定及简化；确定划分圆域的半径和圆心；定义合理角距比弯制圆域；判断是否继续进行圆域划分；以圆域弯制点角距比<Image he="68" wi="135" file="DDA0002518964600000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>为指标,将各圆域降序排列,规定圆域的弯制点顺序,输出最终弯制点弯制顺序T<Sub>1</Sub>和R<Sub>1</Sub>。本发明以变半径圆域划分区域,将弯制点角距比和作为判断条件,可以提高正畸弓丝弯制规划的效率,避免了机器人弯制正畸弓丝过程中出现干涉的问题。(The invention discloses an orthodontic arch wire variable-radius circular domain dividing method based on bending point angular distance ratio and relates to the technical field of orthodontic arch wire bending. The technical points are as follows: converting the orthodontic arch wire curve T into a plane curve T'; setting and simplifying circle domain limiting parameters; determining the radius and the center of a circle to be divided; defining a bending circle domain with a reasonable angular distance ratio; judging whether to continue to divide the circular domain; bending point-angle distance ratio in circular area As an index, descending the order of each circle fieldArranging, defining bending point sequence of circular region, and outputting final bending point bending sequence T 1 And R 1 . The invention divides the area by the variable radius circular area, and takes the sum of the bending point and the angular distance as the judgment condition, thereby improving the efficiency of the bending planning of the orthodontic arch wire and avoiding the problem of interference in the process of bending the orthodontic arch wire by a robot.)

1. The method for dividing the variable-radius circular domain of the orthodontic arch wire based on the bending point-angular distance ratio is characterized by comprising the following steps of: the method comprises the following concrete implementation processes:

step one, dividing data import in a variable radius circular domain and orthodontic arch wire curve conversion:

according to the orthodontic arch wire curve with i bending points of a patient, calculating and inputting an orthodontic arch wire curve bending point information set T ═ T₁，t₂，t₃，...，t_i}，t_i＝(x_i，y_i，z_i) ' coordinates of each orthodontic archwire curve bending point, at each bending point t_iThe upper robot executes different bending movements, and each orthodontic arch wire curve bending point t_iAll correspond to a bending information unit r of a bending point robot_iThe bending information set of the robot for inputting the bending points is R ═ R₁，r₂，r₃，...，r_i}，r_i＝(x_i，y_i，z_i，α_i) ' denotes the coordinates of the bending point and the bending angle of the robot at the time of bending the point, α_iActing on bending points t for the robot_iAn upper bending angle;

centralizing the information of the individualized orthodontic arch wire curve forming control point into the coordinate t of each bending point_i＝(x_i，y_i，z_i) ' z in_iAssigned a value of 0, i.e. z_iObtaining an orthodontic arch wire curve conversion plane orthodontic arch wire curve T' which is equal to 0;

step two, setting of circle domain limiting parameters

Defining unit circle fields with the symbol a₀The unit circle domain represents any bending point t on the curve of the orthodontic arch wire_jCentered at a point l_jIncluding only one bending point t_jThe circular domain of (a); defining unit circle region bending point density by symbolExpressing, unit circle domain bending dot densityThe method is a quantitative description of the tightness degree between a single bending point and an adjacent bending point on a distorted arch wire curve, and specifiesWherein the value 1 in the formula represents a bending point in the unit circle domain,/_jIndicates the bending point t_jThe linear distance between the bending point and the bending point closest to the bending point is that j is greater than or equal to 1 and less than or equal to i; defining the number of bending points in the circular region by symbolsIndicating the number of bending points in the circleIs a radius ofRound area a of_nThe number of inner bending points; defining a bending point angular distance ratio, denoted by the symbol E, which is a quantitative description of the bending complexity of a single bending point, the bending point angular distance ratio of the ith bending point definingIn particular, due to the first bending point t₁Without bending, the bending point t is specified₁Bending point-angular distance ratio E of₁0; defining the sum of the angular distances of the bending points in the circle by symbolsIt is shown that,is to divide the circular domain a_nThe divided bending points are quantitatively described in the whole bending complexity,represents the nth variable radius dividing circular area a on the curve of the orthodontic arch wire_nThe sum of the bending point angular distance ratios of all the bending points in the circle area a is divided when the radius is changed_nThe inner bending points are respectivelyWhen it is prescribedα_mTo act on the bending point t_mThe bending angle of the part is formed,indicating action at bending point t_mAt a bending distance, i.e. bending point t_m-1And t_mThe length of the curve segment between, the value range of m isq represents the number of all bending points in a circular domain which is divided into a variable-radius circular domain on the curve of the orthodontic arch wire, namelyWhen the circular domain is not divided, q is 0, namely the initial value of q is 0, the value range of q is more than or equal to 0 and less than or equal to i, and the density of the bending points of the circular domain is adjustedRatio of angular distance of bending points in circular areaNumber of bending points in the harmony circle regionCollectively referred to as circular domain limiting parameters, the upper limit values of the circular domain limiting parameters are defined and setUpper limit value Q of_maxSetting upIs rho_maxSetting upUpper limit value of (∑ E)_maxDuring the whole circle division process Q_max、ρ_maxAnd (∑ E)_maxConstant, in particular Q_maxAccording to the obtained orthodontic arch wire curve with special bending point density, the arch wire curve is divided into 5 portionsCalculating the unit circle region bending point density of each bending point on the orthodontic arch wire curveNamely, it isIndicates the first bending point t₁The unit circle domain bending point density of (1), wherein_jIndicates the bending point t_jWhen the value range of j is 1 < j < i,when j is 1When j is equal to i Respectively represent line segments t_jt_j+1、t_j-1t_j、t₁t₂、t_i-1t_iCan be removed by comparisonMaximum value ofTo the conditionAnd (3) carrying out verification, specifically:

exist ofIf the information is satisfied, the information set T ═ T is satisfied at the bending point of the orthodontic arch wire curve₁，t₂，t₃，...，t_iThe maximum unit circle bending point density of the bending points in the structure is not more than the upper limit value of the set unit circle bending point densityEach bending point on the curve of the orthodontic arch wire conforms to the bending point density of the unit circular areaThe upper limit value of the bending point density of the unit circular region is less than or equal toIt can be known that on the orthodontic arch wire curve containing i bending points, under the limiting condition of the number of the bending points, no matter the divided circular domain has any number of the bending points, the divided circular domain can still ensure that the density degree of the bending points in the circular domain is within an acceptable range, and the requirement of a bending system on the density of the bending points can be met, so that the influence of the density factor of the bending points does not need to be considered in the process of dividing the circular domain of the orthodontic arch wire curve meeting the requirement, and the method only uses the number of the bending points in the circular domainSum of bending point and angular distance ratio of sum circleLimiting the divided circular domain according to the reference, and skipping to the third step;

step three, determining the radius and the circle center of the divided circle domain:

dividing the circular field to bend the point t_q+1Taking bending points t as starting points_q+1Andthe straight line segments between the two segments are sequentially marked as line segmentsSegment of lineThe line segment with the largest middle length is recorded asNamely, it is Respectively representing line segments The length of the n-th circle segment a to be generated on the curve of the orthodontic arch wire_nIs a line segmentThe radius of the midpoint of (1) is a line segmentHalf of the lengthAt this time, exactly two bending points fall on the boundary line of the circular area, and the newly formed circular area a_nCan just divide the bending points preset in the step threeAll bending points on the orthodontic arch wire curve segment intersected by the specified circle domain boundary line are divided by the circle domain, when the generated circle domain boundary line passes through the bending points, the bending points are also divided by the circle domain, and the orthodontic arch wire curve segment where the divided bending points are located can not be divided by other circle domains any more;is initially ofn is initially 1, i.e. the 1 st circular domain a is first divided₁The bending points divided by the circle area are preset to reach the upper limit value, and the bending points which can be divided at the moment are t₁、t₂、t₃、t₄、t₅And t is₁To divide a circular domain a₁A starting point of (a);

step four, defining a reasonable angular distance ratio bending circle domain:

according toCalculating by straight line segmentIs the center of a circle, toDividing a circular field by radius_nThe ratio of angular distances between the bending points of the circle anddetermine if there is

The method specifically comprises the following steps:

if it is notWhen it is true, straight line segments are used for explanationIs the center of a circle, toRadius-based radius-dividing circle bending point-to-angle ratio sumDoes not exceed the set circular region bending point angular distance ratio and the upper limit value (∑ E)_maxThen, the straight line segment will be usedIs the center of a circle, toThe circle dividing area containing the curve segment of the orthodontic arch wire is defined as a bending circle area a with a reasonable angular distance ratio_nCalculating the number q of all bending points on the orthodontic arch wire curve which are divided by the bending circular domain with the reasonable angular distance ratio, and skipping to the fifth step;

if it is notAre out of standing and existAt this time, the number of the circle domain bending points for dividing the circle domain is not less than 1, and then the number of the circle domain bending points is continuously reduced to divide the circle domain, so thatCalculating the number q of all bending points on the orthodontic arch wire curve which are divided by the bending circular domain with the reasonable angular distance ratio, and skipping to the third step;

if it is notAre out of standing and existTo explain this, the number of the circle bending points for dividing the circle is only 1, and will be represented by t_q+1As a circle center, with a bending point t_q+1To adjacent bending point t_q+2Half of the linear distance therebetweenThe circle dividing area generated for the radius and containing the curve segment of the orthodontic arch wire is defined as a bending circle area a with a reasonable angular distance ratio_nThen the reasonable angular pitch ratio bends the circular area a_nComprises only one bending point t_q+1Calculating the number q of all bending points on the orthodontic arch wire curve which are divided by the bending circular domain with the reasonable angular distance ratio, and skipping to the fifth step;

step five, judging whether to continue to divide the circle domain:

judging whether the number q of all bending points on the orthodontic arch wire curve divided by the bending circular domain with the reasonable angular distance ratio is equal to the number i of the bending points,

the method specifically comprises the following steps:

if the number q of all bending points divided by the bending circular domain by the reasonable angular distance ratio on the orthodontic arch wire curve is not equal to the number i of the bending points, the circular domain division is continued, and n is equal to n +1, namely, the next circular domain is divided, at the moment,

if i-q is more than or equal to 5, the number of the remaining undivided bending points is not less than 5, and then orderWhen the next circle domain is divided for the first time, the bending point which can be divided by the circle domain is preset to just reach the upper limit value, and the step III is skipped;

if i-q is less than 5 and i-q is not equal to 1, indicating that the number of remaining undivided bending points on the curve of the orthodontic arch wire is less than 5 but more than 1, and then controllingWhen the next circular area is divided for the first time, the number of bending points which can be divided by the circular area is equal to the number of remaining non-divided bending points on the orthodontic arch wire curve, and the step is skipped to the step three;

if i-q is less than 5 and i-q is 1, the bending points remained on the curve of the orthodontic arch wire and not divided at the moment are only the last 1 bending points t_iWill be given by t_iAs the center of circle, with t_i-1And t_iHalf of the linear distance therebetweenThe circle dividing area generated for the radius and containing the curve segment of the orthodontic arch wire is defined as a bending circle area a with a reasonable angular distance ratio_nThen the reasonable angular distance is bentCircle-making domain a_nComprises only one bending point t_iJumping to the step six;

if the number q of all bending points divided by the bending circular domain with the reasonable angular distance ratio on the orthodontic arch wire curve is equal to the number i of the bending points, the bending points are divided by the bending circular domain with the reasonable angular distance ratio, and a bending circular domain information set A with the reasonable angular distance ratio is output₁＝{a₁，a₂，...，a_nSkipping to the step six;

step six, outputting the final bending sequence

Calculating each reasonable angular distance ratio bending circle area (a)₁，a₂，...，a_n) The ratio of angular distances between the bending points of the circle andobtaining the angular distance ratio of the bending points in the circular domain and the information setComparing the angle-distance ratios of the circular bending points of the circular bending area with the reasonable angle-distance ratios, and obtaining the sum of the angle-distance ratios of the circular bending points on the assumptionWhereinRepresenting the sum of the angular distances of the bending points of the round area with the s-th reasonable angular distance ratio, s is more than or equal to 1 and less than or equal to n, and the sum of the angular distances of the bending points of the round areaArranging n circular domains in descending order for the index to obtain a descending order reasonable angular-distance ratio bending circular domain information set A₁＝{a₃，a₂，...，a_sIn any one bending circle, in unit bending point densitySorting down the bending points divided by the circle for the indexDefining the sequence of the bending points corresponding to the descending unit bending point density as the bending sequence of the bending points in the circular area, and further obtaining the coordinate matrix T of the orthodontic arch wire curve forming control point₁＝{t₇，t₆，t₅，...，t_mAnd robot bending information set R₁＝{r₇，r₆，r₅，...，r_mWhere t is_mThe bending point with the minimum density of the single bending point in the s-th reasonable angular distance ratio bending circle region is shown, and the final bending point bending sequence T is output₁＝{t₇，t₆，t₅，…，t_m}、R₁＝{r₇，r₆，r₅，...，r_mAnd the program is ended.

Technical Field

The invention relates to a method for dividing a variable-radius circular domain of an orthodontic arch wire based on bending point-angle distance ratio, and belongs to the technical field of bending of orthodontic arch wires.

Background

The malocclusion deformity is the third major oral disease endangering human health, has higher morbidity, and in modern oral medicine, the fixed correction is a common and effective orthodontic treatment means, while the bending of an orthodontic arch wire is the key of the fixed correction technology.

In the process of bending the personalized orthodontic arch wire by the robot, interference may occur between the personalized orthodontic arch wire and the robot bending paw, namely the personalized orthodontic arch wire collides with the robot bending paw, and after the interference occurs, the bending precision of the personalized orthodontic arch wire is greatly influenced, so that the correction effect is influenced, and the bent personalized arch wire cannot be applied to clinical treatment; research shows that in the process of forward bending the individual orthodontic arch wire, the forward bending is to bend the unbent orthodontic arch wire into a complex formed arch wire, interference is often caused by unreasonable bending sequence of forming control points, the reasonable bending sequence of the forming control points can effectively avoid the occurrence of interference, and the obtaining of the reasonable bending sequence of the forming control points is a necessary premise for realizing digital bending of the orthodontic arch wire.

For the research of the circular domain dividing method for the orthodontic arch wire bending planning, an equal-radius circular domain dividing method is provided in an invention patent with an authorized publication number of CN107647925B (a circular domain dividing method for the orthodontic arch wire bending planning) issued by the inventor, the zones are divided on an orthodontic arch wire curve, and finally each zone is sequenced, so as to obtain the bending sequence of the final bending point, although the method has a certain application value for the orthodontic arch wire bending planning, because the method only divides the orthodontic arch wire curve by an unboosted homogenization standard, the divided circular domain intervals usually have the condition that the bending point density is too large or too small, namely the divided intervals do not fully consider the personalized characteristics of the distribution information of the bending points on the orthodontic arch wire curve, for example, the bending points on the personalized orthodontics of patients often have relatively small unit bending point density, when the individual orthodontic arch wire is divided into circular areas, the existing orthodontic arch wire forming control point bending sequence planning method is poor in rationality, and efficient digital bending of the individual orthodontic arch wire cannot be achieved, so that idle stroke invalid actions, mutual interference actions in the bending process and complex actions of the bending motion of the bending robot caused by unreasonable bending sequence planning cannot be effectively avoided, the advantages of the bending robot cannot be maximized, and the bending efficiency cannot be obviously improved.

Disclosure of Invention

Aiming at the problems, the invention provides an orthodontic arch wire variable-radius circular domain dividing method based on bending point angular distance ratio, which solves the problem that the prior orthodontic arch wire bending technical field lacks an efficient bending sequence planning method aiming at an orthodontic arch wire with relatively low unit bending point density, so as to avoid the situation of too high bending difficulty when dividing the bending points of an orthodontic arch wire with special attributes, is beneficial to reasonably planning the bending sequence and further realizes the efficient digital bending of the orthodontic arch wire.

A method for dividing an orthodontic arch wire variable-radius circular domain based on bending point-angular distance ratio sum is specifically realized by the following steps:

step one, dividing data import in a variable radius circular domain and orthodontic arch wire curve conversion:

according to the orthodontic arch wire curve with i bending points of a patient, calculating and inputting an orthodontic arch wire curve bending point information set T ═ T₁，t₂，t₃，...，t_i}，t_i＝(x_i，y_i，z_i) ' coordinates of each orthodontic archwire curve bending point, at each bending point t_iThe upper robot executes different bending movements, and each orthodontic arch wire curve bending point t_iAll correspond to a bending information unit r of a bending point robot_iThe bending information set of the robot for inputting the bending points is R ═ R₁，r₂，r₃，...，r_i}，r_i＝(x_i，y_i，z_i，α_i) ' denotes the coordinates of the bending point and the bending angle of the robot at the time of bending the point, α_iActing on bending points t for the robot_iAn upper bending angle;

centralizing the information of the individualized orthodontic arch wire curve forming control point into the coordinate t of each bending point_i＝(x_i，y_i，z_i) ' z in_iAssigned a value of 0, i.e. z_iObtaining an orthodontic arch wire curve conversion plane orthodontic arch wire curve T' which is equal to 0;

step two, setting of circle domain limiting parameters

Defining unit circle fields with the symbol a₀The unit circle domain represents any bending point t on the curve of the orthodontic arch wire_jCentered at a point l_jIncluding only one bending point t_jThe circular domain of (a); defining unit circle region bending point density by symbolExpressing, unit circle domain bending dot densityThe method is a quantitative description of the tightness degree between a single bending point and an adjacent bending point on a distorted arch wire curve, and specifiesWherein the value 1 in the formula represents a bending point in the unit circle domain,/_jIndicates the bending point t_jThe linear distance between the bending point and the bending point closest to the bending point is that j is greater than or equal to 1 and less than or equal to i; defining the number of bending points in the circular region by symbolsIndicating the number of bending points in the circleIs a radius ofRound area a of_nThe number of inner bending points; defining a bending point angular distance ratio, denoted by the symbol E, which is a quantitative description of the bending complexity of a single bending point, the bending point angular distance ratio of the ith bending point definingIn particular, due to the first bending point t₁Without bending, the bending point t is specified₁Bending point-angular distance ratio E of₁0; defining the sum of the angular distances of the bending points in the circle by symbolsIt is shown that,is to divide the circular domain a_nQuantitative drawing of the whole bending complexity of the divided bending pointsIn the above-mentioned manner,represents the nth variable radius dividing circular area a on the curve of the orthodontic arch wire_nThe sum of the bending point angular distance ratios of all the bending points in the circle area a is divided when the radius is changed_nThe inner bending points are respectivelyWhen it is prescribedα_mTo act on the bending point t_mThe bending angle of the part is formed,indicating action at bending point t_mAt a bending distance, i.e. bending point t_m-1And t_mThe length of the curve segment between, the value range of m isq represents the number of all bending points in a circular domain which is divided into a variable-radius circular domain on the curve of the orthodontic arch wire, namelyWhen the circular domain is not divided, q is 0, namely the initial value of q is 0, the value range of q is more than or equal to 0 and less than or equal to i, and the density of the bending points of the circular domain is adjustedRatio of angular distance of bending points in circular areaNumber of bending points in the harmony circle regionCollectively referred to as circular domain limiting parameters, the upper limit values of the circular domain limiting parameters are defined and setUpper limit value Q of_maxSetting upIs rho_maxSetting upUpper limit value of (∑ E)_maxDuring the whole circle division process Q_max、ρ_maxAnd (∑ E)_maxConstant, in particular Q_maxAccording to the obtained orthodontic arch wire curve with special bending point density, the arch wire curve is divided into 5 portionsCalculating the unit circle region bending point density of each bending point on the orthodontic arch wire curveNamely, it isIndicates the first bending point t₁The unit circle domain bending point density of (1), wherein_jIndicates the bending point t_jWhen the value range of j is 1 < j < i,when j is 1When j is equal to iRespectively represent line segments t_jt_j+1、t_j-1t_j、t₁t₂、t_i-1t_iCan be removed by comparisonMaximum value ofTo the conditionAnd (3) carrying out verification, specifically:

exist ofIf the information is satisfied, the information set T ═ T is satisfied at the bending point of the orthodontic arch wire curve₁，t₂，t₃，...，t_iThe maximum unit circle bending point density of the bending points in the structure is not more than the upper limit value of the set unit circle bending point densityEach bending point on the curve of the orthodontic arch wire conforms to the bending point density of the unit circular areaThe upper limit value of the bending point density of the unit circular region is less than or equal toIt can be known that on the orthodontic arch wire curve containing i bending points, under the limiting condition of the number of the bending points, no matter the divided circular domain has any number of the bending points, the divided circular domain can still ensure that the density degree of the bending points in the circular domain is within an acceptable range, and the requirement of a bending system on the density of the bending points can be met, so that the influence of the density factor of the bending points does not need to be considered in the process of dividing the circular domain of the orthodontic arch wire curve meeting the requirement, and the method only uses the number of the bending points in the circular domainSum of bending point and angular distance ratio of sum circleLimiting the divided circular domain according to the reference, and skipping to the third step;

step three, determining the radius and the circle center of the divided circle domain:

dividing the circular field to bend the point t_q+1Taking bending points t as starting points_q+1Andthe straight line segments between the two segments are sequentially marked as line segmentsSegment of lineThe line segment with the largest middle length is recorded asNamely, it is Respectively representing line segments The length of the n-th circle segment a to be generated on the curve of the orthodontic arch wire_nIs a line segmentThe radius of the midpoint of (1) is a line segmentHalf of the lengthAt this time, exactly two bending points fall on the boundary line of the circular area, and the newly formed circular area a_nCan just divide the bending points preset in the step threeAll bending points on the orthodontic arch wire curve segment intersected by the specified circle domain boundary line are divided by the circle domain, when the generated circle domain boundary line passes through the bending points, the bending points are also divided by the circle domain, and the orthodontic arch wire curve segment where the divided bending points are located can not be divided by other circle domains any more;is initially ofn is initially 1, i.e. the 1 st circular domain a is first divided₁The bending points divided by the circle area are preset to reach the upper limit value, and the bending points which can be divided at the moment are t₁、t₂、t₃、t₄、t₅And t is₁To divide a circular domain a₁A starting point of (a);

step four, defining a reasonable angular distance ratio bending circle domain:

according toCalculating by straight line segmentIs the center of a circle, toDividing a circular field by radius_nThe ratio of angular distances between the bending points of the circle anddetermine if there is

The method specifically comprises the following steps:

if it is notWhen it is true, straight line segments are used for explanationIs the center of a circle, toRadius-based radius-dividing circle bending point-to-angle ratio sumDoes not exceed the set circular region bending point angular distance ratio and the upper limit value (∑ E)_maxThen, the straight line segment will be usedIs the center of a circle, toThe circle dividing area containing the curve segment of the orthodontic arch wire is defined as a bending circle area a with a reasonable angular distance ratio_nCalculating the number q of all bending points on the orthodontic arch wire curve which are divided by the bending circular domain with the reasonable angular distance ratio, and skipping to the fifth step;

if it is notAre out of standing and existAt this time, the number of the circle domain bending points for dividing the circle domain is not less than 1, and then the number of the circle domain bending points is continuously reduced to divide the circle domain, so thatCalculating the number q of all bending points on the orthodontic arch wire curve which are divided by the bending circular domain with the reasonable angular distance ratio, and skipping to the third step;

if it is notAre out of standing and existTo explain this, the number of the circle bending points for dividing the circle is only 1, and will be represented by t_q+1As a circle center, with a bending point t_q+1To adjacent bending point t_q+2Half of the linear distance therebetweenThe circle dividing area generated for the radius and containing the curve segment of the orthodontic arch wire is defined as a bending circle area a with a reasonable angular distance ratio_nThen the reasonable angular pitch ratio bends the circular area a_nComprises only one bending point t_q+1Calculating the number q of all bending points on the orthodontic arch wire curve which are divided by the bending circular domain with the reasonable angular distance ratio, and skipping to the fifth step;

step five, judging whether to continue to divide the circle domain:

judging whether the number q of all bending points on the orthodontic arch wire curve divided by the bending circular domain with the reasonable angular distance ratio is equal to the number i of the bending points,

the method specifically comprises the following steps:

if the number q of all bending points divided by the bending circular domain by the reasonable angular distance ratio on the orthodontic arch wire curve is not equal to the number i of the bending points, the circular domain division is continued, and n is equal to n +1, namely, the next circular domain is divided, at the moment,

if i-q is more than or equal to 5, the number of the remaining undivided bending points is not less than 5, and then orderWhen the next circle domain is divided for the first time, the bending point which can be divided by the circle domain is preset to just reach the upper limit value, and the step III is skipped;

if i-q is less than 5 and i-q is not equal to 1, indicating that the number of remaining undivided bending points on the curve of the orthodontic arch wire is less than 5 but more than 1, and then controllingI.e. when the first division of the next circular field is performedThe number of the bending points which can be divided in the circular area is the number of the remaining non-divided bending points on the orthodontic arch wire curve, and the step III is skipped;

if i-q is less than 5 and i-q is 1, the bending points remained on the curve of the orthodontic arch wire and not divided at the moment are only the last 1 bending points t_iWill be given by t_iAs the center of circle, with t_i-1And t_iHalf of the linear distance therebetweenThe circle dividing area generated for the radius and containing the curve segment of the orthodontic arch wire is defined as a bending circle area a with a reasonable angular distance ratio_nThen the reasonable angular pitch ratio bends the circular area a_nComprises only one bending point t_iJumping to the step six;

if the number q of all bending points divided by the bending circular domain with the reasonable angular distance ratio on the orthodontic arch wire curve is equal to the number i of the bending points, the bending points are divided by the bending circular domain with the reasonable angular distance ratio, and a bending circular domain information set A with the reasonable angular distance ratio is output₁＝{a₁，a₂，...，a_nSkipping to the step six;

step six, outputting the final bending sequence

Calculating each reasonable angular distance ratio bending circle area (a)₁，a₂，…，a_n) The ratio of angular distances between the bending points of the circle andobtaining the angular distance ratio of the bending points in the circular domain and the information setComparing the angle-distance ratios of the circular bending points of the circular bending area with the reasonable angle-distance ratios, and obtaining the sum of the angle-distance ratios of the circular bending points on the assumptionWhereinSum of angular distances of circle bending points representing the s-th rational angular distance ratio bending circle, 1S is less than or equal to n, and the sum of the angular distances of the bending points in the circular domainArranging n circular domains in descending order for the index to obtain a descending order reasonable angular-distance ratio bending circular domain information set A₁＝{a₃，a₂，…，a_sIn any one bending circle, in unit bending point densityThe bending points divided by the circular area are arranged in a descending order for the index, the order of the bending points corresponding to the density of the bending points in the descending order unit is defined as the bending order of the bending points in the circular area, and then the coordinate matrix T of the orthodontic arch wire curve forming control point is obtained₁＝{t₇，t₆，t₅，…，t_mAnd robot bending information set R₁＝{r₇，r₆，r₅，…，r_mWhere t is_mThe bending point with the minimum density of the single bending point in the s-th reasonable angular distance ratio bending circle region is shown, and the final bending point bending sequence T is output₁＝{t₇，t₆，t₅，…，t_m}、R₁＝{r₇，r₆，r₅，...，r_mAnd the program is ended.

The invention has the beneficial effects that:

1. the invention provides a unit circular domain bending point density aiming at a circular domain dividing methodThe concept of (1) quantitatively describing the density between a single bending point and an adjacent bending point, and the density of the bending points in a unit circle domainSet up as one of the circle domain limiting parametersUpper limit value ofVerifying maximum unit circle-domain bending point density of bending points on orthodontic arch wire curve in advance before dividing circle domainNo greater than the upper limit of the bending point density of unit circle regionThe unit circle region bending point density of each bending point on the curve of the orthodontic arch wire can be obtainedThe method meets the set requirement, avoids overlarge intensity of bending points on the divided circular areas caused by the fact that the density of the bending points of the unit circular areas does not meet the set requirement, provides the constraint of precondition for the method, and further improves the operability and accuracy of the method.

2. Compared with the invention patent 'a plane variable radius circular domain dividing method for orthodontic arch wire bending planning' filed by the inventor on the same day,the method is based on the premise that bending points on the individual orthodontic arch wire curve have the special attribute of low unit bending point density, and the bending point density of the unit circular region is increased before the divisionThe whole judgment is carried out, so that the bending point density of the circular domain is omitted in the process of dividing the circular domainSo that the circle division process is based entirely on the sum of the circle bending point-angular distance ratiosThe method not only meets the requirement of the bending movement of the robot, but also simplifies the dividing process, reduces the complexity of the bending planning algorithm and improves the planning efficiency of the bending sequence.

3. Compared with the method for dividing the variable-radius circular domain of the orthodontic arch wire based on the bending point density, which is filed on the same day by the inventor of the invention, although both methods are suitable for a class of individual orthodontic arch wire curves with special attributes, the method mentioned in the method for dividing the variable-radius circular domain of the orthodontic arch wire based on the bending point density is emphasized on the premise that the angular distance ratio of each bending point meets the set requirement, and further, the number of the bending points in the circular domain is only usedAnd circle bending point densityAs the basis for dividing the bending circular domain, the method emphasizes on the premise that the density of unit bending points meets the set requirement, and further, the number of the bending points in the circular domain is only usedSum of bending point and angular distance ratio of sum circleAs a basis for dividing the bending circular domain, the two methods have different application conditions when the orthodontic arch wire bending sequence planning is carried out, so that the method is mutually compensated with the other method, and further a series of methods for the orthodontic arch wire bending sequence planning are perfected.

4. After all bending points are divided, the invention uses the circle domain bending point density defined aiming at the circle domain divisionN circular domains are arranged in descending order for the index to obtain a descending order reasonable angular distance ratio bending circular domain information set, and the information set is specified in any bending circular domain according to the unit bending point densityThe bending points divided by the circular area are arranged in a descending order for indexes, the order of the bending points corresponding to the density of the bending points in the descending order unit is defined as the bending order of the bending points in the circular area, and the determined bending order of each bending point is ensured, so that the operability and the accuracy of the orthodontic arch wire bending planning are improved.

5. Compared with the invention patent of CN107647925B, the invention provides a circle domain dividing method for orthodontic arch wire bending planning, which is based on the division of the circle domain with variable radius, fully considers the individual characteristics of the distribution information of the bending points on the curve of the orthodontic arch wire for the arch wire with specific attributes, i.e. the density of the unit bending points on the individual orthodontic arch wire of the patient is relatively small, the density of the unit bending points of each bending point is smaller than the specified upper limit value, provides a circle domain limiting parameter for dividing the curve of the orthodontic arch wire, so that the dividing process is not divided by an unjustified homogenization standard, but the radius of the circle domain is continuously changed to adapt to the regulation of the parameters of the circle domain, generates a series of variable radius bending circle domains based on the bending point angular distance ratio and improves the rationality of the orthodontic shaping control point bending sequence planning method, the idle stroke invalid action, the mutual interference action in the bending process and the complex action of the bending motion of the bending robot are effectively avoided, the maximization of the advantages of the bending robot is fully exerted, and the bending efficiency is obviously improved.

Drawings

For ease of illustration, the invention is described in detail by the following detailed description and the accompanying drawings.

FIG. 1 is a flow chart of a method for dividing a variable-radius circular domain of an orthodontic arch wire based on a bending point-to-angular distance ratio;

fig. 2 is a schematic view of distribution of individual orthodontic arch wire bending points;

fig. 3 is a schematic diagram of a curve of an individual orthodontic arch wire divided by a variable radius circular domain based on a bending point angular distance ratio sum;

Detailed Description

For the purposes of promoting a clear understanding of the objects, aspects and advantages of the invention, reference will now be made to the following description of the preferred embodiments illustrated in the accompanying drawings, with the understanding that the description is illustrative only and is not intended to limit the scope of the invention, and that the following description will omit descriptions of well-known structures and techniques in order to avoid unnecessarily obscuring the concepts of the invention.