阅读说明：本技术 一种基于正畸弓丝弯制点单位角距比和的等角度划分角度确定方法 (Equal-angle division angle determination method based on orthodontics arch wire bending point unit angular distance ratio sum ) 是由 姜金刚 郭亚峰 姚亮 吴殿昊 张永德 曾阳 于 2020-06-01 设计创作，主要内容包括：一种基于正畸弓丝弯制点单位角距比和的等角度划分角度确定方法,它涉及正畸弓丝弯制技术领域,当正畸弓丝曲线上各弯制点的单位弯制点密度都相对较小且均小于设定的单位弯制点密度上限值的情况下,在应用等角度划分为此类正畸弓丝规划弯制顺序时,基于正畸弓丝曲线成形控制点信息集,成形控制点的机器人运动信息集,结合机器人弯制正畸弓丝的特点设定等角度域弯制点单位角距比和上限值,建立了一种基于正畸弓丝弯制点单位角距比和的等角度划分角度确定方法,在等角度划分的过程中根据等角度域的单位角距比和改变划分角度,最终确定划分角度并输出。本发明通过对划分区域弯制难度的定量约束,保证了划分角度确定的合理性,提高了规划效率。(An equal angle division angle determination method based on the orthodontics arch wire bending point unit angular distance ratio and the equal angle division angle is established when the unit bending point density of each bending point on an orthodontics arch wire curve is relatively small and is smaller than the set upper limit value of the unit bending point density, and when the equal angle division is applied to the orthodontics arch wire planning bending sequence, the equal angle division angle determination method based on the orthodontics arch wire bending point unit angular distance ratio and the equal angle division angle is finally determined and output according to the unit angular distance ratio and the change division angle of the equal angle domain in the equal angle division process. The method ensures the rationality of determining the division angle and improves the planning efficiency by the quantitative constraint of the bending difficulty of the divided area.)

1. An equal-angle division angle determination method based on the sum of unit angular distance ratios of orthodontic arch wire bending points is characterized in that: the method comprises the following concrete implementation processes:

step one, dividing data import at equal angles:

inputting an information set M ═ M of the forming control point of the personalized orthodontic arch wire curve according to the personalized orthodontic arch wire curve with i forming control points of the patient₁，m₂，m₃，...，m_i}，m_i＝(u_i，v_i，w_i) 'for each individual orthodontic archwire curve shaping control point's coordinates, each orthodontic archwire curve shaping control point m_iAll correspond to a forming control point robot motion information unit n_iSo the robot motion information set of the input shaping control point is N ═ N₁，n₂，n₃，...，n_i}，n_iRepresenting the coordinates of the forming control point and the bending angle, n, of the robot when bending the point_i＝(u_i，v_i，w_i，α_i)'，u_i、v_i、w_iFor the forming control point m_iα_iActing on forming control points m for robots_iThe upper bending angle is used for inputting an orthodontic arch wire curve forming control point information set M and a robot motion information set N of a forming control point into an orthodontic arch wire bending system, and the unit angular distance ratio and the upper limit value (∑ E) of the equal-angle-domain bending point are set according to the characteristics of the robot bending orthodontic arch wire⁰)_maxAnd setting an upper limit value of the bending point density of the bending point unit

The coordinates of two end points of the personalized orthodontic arch wire curve are m_s(u_s，v_s，w_s)，m_e(u_e，v_e，w_e) The left end point m of the curve of the arch wire is adjusted_sSet as a forming control point m₀The right end point m of the arch wire curve is adjusted_eSet as a forming control point m_i+1Using the middle point m of the left and right end points of the arch wire curve_o As a circle center O;

aiming at equal angle division, any bending point m on the curve of the orthodontic arch wire is defined_jHas a unit bending point density ofWherein R is_jIndicates a bending point m_jRadius formed by connecting line with circle center O and bending point m_j+1The larger radius value, phi, of the radii formed by lines connecting the centers of circles O_jIndicates a bending point m_jRadius formed by connecting line with circle center O and bending point m_j+1Calculating the unit bending point density of each bending point according to the angle value between the radius formed by the connecting line of the center of circle and the circle O, and when the unit bending point density of each bending point is smaller than the upper limit value of the unit bending point densityThen, jumping to the second step;

step two, performing orthodontic arch wire curve coordinate conversion and setting an initial value of equal-angle division parts a:

centralizing the information of the individual orthodontic arch wire forming control points into the coordinate m of each forming control point_i＝(u_i,v_i,w_i) ' w in_iAssigned a value of 0, i.e. order w_iObtaining an orthodontic arch wire conversion curve M' as 0;

aiming at equal angle division, any bending point m on the curve of the orthodontic arch wire is defined_jUnit angular distance ratio ofα therein_jIndicates a bending point m_jThe bending angle of the steel plate is adjusted,indicates a bending point m_jAnd bending point m_j+1The unit angular distance ratio of each bending point on the curve of the orthodontic arch wire is calculated, and the unit angular distance ratios of all the bending points are summed and recorded as (∑ E)⁰)_{General assembly}；

Dividing the curve of the orthodontic arch wire into equal angle domains with equal angle a by taking O as the center of a circle, namely forming an equal angle domain (b)₁，b₂，...，b_a) The initial part number a of the regular equal angle division is equal to the sum of all bending point unit angular distance ratios, and the ratio of the set equal angle domain unit angular distance ratio to the upper limit value is rounded and then added with one, namely the initial part number a is [ (∑ E)⁰)_{General assembly}/(∑E⁰)_max]+1；

Step three, calculating an angle beta of equal angle division:

an equal angle domain (b) formed by dividing the equal angle₁，b₂，...，b_a) The corresponding angles β are all equal, and the angle β divided by equal angles is equal to the ratio of the total angle pi of the arch wire curve to the part a divided by equal angles, namely

Will have equal angle domain b_kAs a start field for checking whether to increase the equal-angle division number a, initializing k to 1;

step four, judging whether the equal-angle division number a is increased:

calculate all belonging equianglesDegree domain b_kThe unit angular distance ratio of the bending points, i.e. in the equal angle domain b_kUnit angular distance ratio of all bending points inside the left and right borders, in particular if the bending points are located in the equal angular domain b_kOn the left boundary line of the bending point, the bending point belongs to the last equal angle domain b_k-1If the bending point is located in the equal angle domain b_kOn the right boundary line of (a), the bending point belongs to the current equal angle domain b_kWill be in equal angular domain b_kThe sum of the unit angular distances of all bending points in the curve is recorded

Judgment ofWhether the result is true or not;

if it is notIf yes, it indicates the equal angle domain b_kAccording with the equal angle division requirement, jumping to the fifth step;

if it is notIf not, the equal angle domain b is indicated_kDoes not meet the requirement of equal-angle division and is in an equal-angle domain b_kThe bending difficulty of the inner bending point is high, the current equal-angle division number cannot meet the division requirement, and the division number should be increased, so that a is a +1, and the step three is skipped;

step five, judging whether to continuously check the equal angle domain:

judging whether k is more than a;

if k is less than a, the a equal angle domains are not checked, and the next equal angle domain should be checked continuously, so that k is equal to k +1, and the step four is skipped;

if k is less than a, the a equal angle domains are verified, and the step six is skipped;

step six, determining an equal angle domain interval and outputting an equal angle division angle beta:

will be in equal angular domain (b)₁，b₂，...，b_a) The equal angle domain interval { b with equal angle is determined₁，b₂，...，b_aAnd (4) counting the sum of the unit angular distance ratios of all the equal-angle domain intervalsOutputting equal angle domain interval information set B ═ B₁，b₂，…，b_a}；

And when the orthodontic arch wire curve is divided at the equal angle, determining the division angle to be beta, outputting the division angle beta at the moment, and ending the program.

Technical Field

The invention relates to an equal-angle division angle determination method based on a unit angular distance ratio sum of orthodontic arch wire bending points, and belongs to the technical field of orthodontic arch wire bending.

Background

The malocclusion deformity is the third major oral disease which crisis the health of human body, the incidence rate is higher among people, in modern oral medicine, the fixed correction is a common and effective orthodontic treatment means, the bending of the orthodontic arch wire is the key of the fixed correction technology, in recent years, the fixed correction is deeply influenced by the digital manufacturing technology, the traditional oral manufacturing and processing technology is revolutionarily changed, the oral orthodontic field also benefits from the digital technology, the processing of the arch wire in the orthodontic appliance is developing towards digitization, however, the efficient planning of the bending point sequence is the premise of realizing the digital processing of the arch wire, improving the efficiency of bending the orthodontic arch wire by a robot and ensuring the bending precision.

When the sequence planning of the bending points of the individual arch wire is carried out, the equal angle division is a bending sequence planning method which is frequently used in the technical field of bending, the curve of the orthodontic arch wire is divided into a series of equal angle equal division domains with equal angles, so the determination of the division angles becomes the key step of the equal angle division when the equal angle division is carried out, in addition, the distribution of the bending points on the individual orthodontic arch wire is relatively dispersed, namely the density of the unit bending points of each bending point on the arch wire curve is relatively lower, when the density of the unit bending points of each bending point on the arch wire curve is smaller than the upper limit value of the density of the unit bending points set according to the bending orthodontic arch wire of a robot, due to the particularity of the distribution of the bending points, when the equal angle domain division is carried out on the individual orthodontic arch wire, the technical field of the existing orthodontic bending lacks a reasonable determination method for the equal angle division of the orthodontic arch wire, the angle is determined according to the convention and is set in advance according to the past experience, once the angle is set, the angle cannot be changed in the dividing process, the angle cannot be changed according to the bending difficulty of the bending points in the equal-angle domain, and the digital and accurate bending of the orthodontic arch wire is difficult to realize.

Disclosure of Invention

Aiming at the problems, the invention provides an equal angle division angle determination method based on the bending point unit angular distance ratio sum of the orthodontic arch wire, solves the problem that the prior orthodontic arch wire bending technical field lacks a determination method for the equal angle division of the orthodontic arch wire, realizes reasonable division of the orthodontic arch wire, avoids the interference in the bending process, and further realizes the efficient digital bending of the orthodontic arch wire.

An equal angle division angle determination method based on the unit angular distance ratio sum of orthodontic arch wire bending points comprises the following specific implementation processes:

step one, dividing data import at equal angles:

inputting an information set M ═ M of the forming control point of the personalized orthodontic arch wire curve according to the personalized orthodontic arch wire curve with i forming control points of the patient₁，m₂，m₃，...，m_i}，m_i＝(u_i，v_i，w_i) 'for each individual orthodontic archwire curve shaping control point's coordinates, each orthodontic archwire curve shaping control point m_iAll correspond to a forming control point robot motion information unit n_iSo the robot motion information set of the input shaping control point is N ═ N₁，n₂，n₃，...，n_i}，n_iRepresenting the coordinates of the forming control point and the bending angle, n, of the robot when bending the point_i＝(u_i，v_i，w_i，α_i)'，u_i、v_i、w_iFor the forming control point m_iα_iActing on forming control points m for robots_iThe upper bending angle is used for inputting an orthodontic arch wire curve forming control point information set M and a robot motion information set N of a forming control point into an orthodontic arch wire bending system, and the unit angular distance ratio and the upper limit value (∑ E) of the equal-angle-domain bending point are set according to the characteristics of the robot bending orthodontic arch wire⁰)_maxAnd setting an upper limit value of the density of the unit bending point

The coordinates of two end points of the personalized orthodontic arch wire curve are m_s(u_s，v_s，w_s)，m_e(u_e，v_e，w_e) The left end point m of the curve of the arch wire is adjusted_sSet as a forming control point m₀The right end point m of the arch wire curve is adjusted_eSet as a forming control point m_i+1Using the middle point m of the left and right end points of the arch wire curve_o As a circle center O;

aiming at equal angle division, any bending point m on the curve of the orthodontic arch wire is defined_jHas a unit bending point density ofWherein R is_jIndicates a bending point m_jRadius formed by connecting line with circle center O and bending point m_j+1The larger radius value, phi, of the radii formed by lines connecting the centers of circles O_jIndicates a bending point m_jRadius formed by connecting line with circle center O and bending point m_j+1Calculating the unit bending point density of each bending point according to the angle value between the radius formed by the connecting line of the center of circle and the circle O, and when the unit bending point density of each bending point is smaller than the upper limit value of the unit bending point densityThen, jumping to the second step;

step two, performing orthodontic arch wire curve coordinate conversion and setting an initial value of equal-angle division parts a:

centralizing the information of the individual orthodontic arch wire forming control points into the coordinate m of each forming control point_i＝(u_i,v_i,w_i) ' w in_iThe value is assigned to be 0 and,fast order w_iObtaining an orthodontic arch wire conversion curve M' as 0;

aiming at equal angle division, any bending point m on the curve of the orthodontic arch wire is defined_jUnit angular distance ratio ofα therein_jIndicates a bending point m_jThe bending angle of the steel plate is adjusted,indicates a bending point m_jAnd bending point m_j+1The unit angular distance ratio of each bending point on the curve of the orthodontic arch wire is calculated, and the unit angular distance ratios of all the bending points are summed and recorded as (∑ E)⁰)_{General assembly}；

Dividing the curve of the orthodontic arch wire into equal angle domains with equal angle a by taking O as the center of a circle, namely forming an equal angle domain (b)₁，b₂，...，b_a) The initial part number a of the regular equal angle division is equal to the sum of all bending point unit angular distance ratios, and the ratio of the set equal angle domain unit angular distance ratio to the upper limit value is rounded and then added with one, namely the initial part number a is [ (∑ E)⁰)_{General assembly}/(∑E⁰)_max]+1；

Step three, calculating an angle beta of equal angle division:

an equal angle domain (b) formed by dividing the equal angle₁，b₂，...，b_a) The corresponding angles β are all equal, and the angle β divided by equal angles is equal to the ratio of the total angle pi of the arch wire curve to the part a divided by equal angles, namely

Will have equal angle domain b_kAs a start field for checking whether to increase the equal-angle division number a, initializing k to 1;

step four, judging whether the equal-angle division number a is increased:

all the parameters belonging to the equal angle domain b are calculated_kThe unit angular distance ratio of the bending points, i.e. in the equal angle domain b_kUnit angular distance ratio of all bending points inside the left and right borders, in particular if the bending points are located in the equal angular domain b_kOn the left boundary line of the bending point, the bending point belongs to the last equal angle domain b_k-1If the bending point is located in the equal angle domain b_kOn the right boundary line of (a), the bending point belongs to the current equal angle domain b_kWill be in equal angular domain b_kThe sum of the unit angular distances of all bending points in the curve is recorded

Judgment ofWhether the result is true or not;

if it is notIf yes, it indicates the equal angle domain b_kAccording with the equal angle division requirement, jumping to the fifth step;

if it is notIf not, the equal angle domain b is indicated_kDoes not meet the requirement of equal-angle division and is in an equal-angle domain b_kThe bending difficulty of the inner bending point is high, the current equal-angle division number cannot meet the division requirement, and the division number should be increased, so that a is a +1, and the step three is skipped;

step five, judging whether to continuously check the equal angle domain:

judging whether k is more than a;

if k is less than a, the a equal angle domains are not checked, and the next equal angle domain should be checked continuously, so that k is equal to k +1, and the step four is skipped;

if k is less than a, the a equal angle domains are verified, and the step six is skipped;

step six, determining an equal angle domain interval and outputting an equal angle division angle beta:

will be in equal angular domain (b)₁，b₂，...，b_a) The equal angle domain interval { b with equal angle is determined₁，b₂，...，b_aAnd (4) counting the sum of the unit angular distance ratios of all the equal-angle domain intervalsOutputting equal angle domain interval information set B ═ B₁，b₂，...，b_a}；

And when the orthodontic arch wire curve is divided at the equal angle, determining the division angle to be beta, outputting the division angle beta at the moment, and ending the program.

The invention has the beneficial effects that:

1. in the process of determining the angles of the equiangular division of the orthodontics arch wire, the invention provides the concept of unit bending point density, the concentration degree of the distribution of the bending points on the orthodontics arch wire curve is quantitatively described through the provision of the unit bending point density, and the upper limit value of the unit bending point density is set according to the characteristics of the orthodontics arch wire bent by the robotTherefore, the concentration degree of distribution of bending points on the orthodontic arch wire curve is limited, and the determination of the angle during equal-angle division of the orthodontic arch wire curve is facilitated based on the comparison of the unit angular distance of the bending points.

2. When the initial value of the division number a is set, the invention considers the sum of the unit angular distance ratios of all bending points on the orthodontic arch wire curve (∑ E)⁰)_{General assembly}And a unit angular distance ratio and an upper limit value (∑ E) of the bending point in the equal angle domain⁰)_maxAnd after the ratio of the number of the division parts is rounded, one is used as an initial value of the division part number a, the setting of the initial part number reduces unnecessary circulation, reduces the calculation scale and improves the efficiency of equal-angle division.

3. Compared with the method for determining the equal angle division of the orthodontic arch wire bending sequence planning, which is invented by the inventor on the same day, the method judges the concentration degree of distribution of bending points on an orthodontic arch wire curve, namely judges that the unit bending point density of each bending point on the orthodontic arch wire curve meets the division requirement, and then determines the angle of the orthodontic arch wire when the orthodontic arch wire is divided by the equal angle, and only the sum of the unit angular distances of the bending points in the equal angle domain is needed during division, so that the cycle times are reduced, the calculation scale is reduced, and the division efficiency of the arch wires of the same type with specific attributes is improved.

4. Compared with the invention patent of an equiangular division orthodontic arch wire bending sequence planning method which is granted by the inventor and has the publication number of CN107714203B, the method proposes that the unit bending point density of the bending points on the orthodontics arch wire with specific attributes is relatively small, the unit bending point density of each bending point is smaller than the upper limit value of the specified unit bending point density, and proposes a concept based on the unit angular distance ratio sum of the bending points of the orthodontics arch wire for determining the division angle of equiangular division of the orthodontic arch wire, so that the equiangular division process is not divided by an unjustified homogenization standard, but the bending points in the divided equiangular domain meet the upper limit requirement of the bending difficulty, the angle values of the divided equiangular domain are continuously changed, and finally a series of equiangular domain intervals meeting the unit angular distance ratio and the requirement of the bending points in the equiangular domain are generated, therefore, the angles of the equal-angle domain intervals are determined, the rationality of the planning method of the bending sequence of the orthodontic arch wire forming control points is improved, idle stroke invalid actions generated by the bending robot, mutual interference actions in the bending process and complex bending movement actions are effectively avoided, the advantages of the bending robot are fully played to the maximum, and the bending efficiency is obviously improved.

5. Compared with the method for determining the equal angle division angle based on the density of the bending points of the orthodontic arch wire, which is invented by the inventor on the same day, although the two methods are both suitable for a type of individual orthodontic arch wire curves with special attributes, the premise of emphasizing the method mentioned in the method for determining the equal angle division angle based on the density of the bending points of the orthodontic arch wire is that the bending point of each bending pointThe unit angular distance ratio meets the set requirement, and the bending point density is only formed in an equal angular domainAs a basis for determining the equal-angle division angle, the method emphasizes on the premise that the unit bending point density of the bending points meets the set requirement, and further, the sum of the unit angular distance ratio of the bending points in the equal-angle domain is only usedAs the determination basis of the equal-angle division angle, the two methods have different application conditions when the equal-angle division angle is determined, so that the method is mutually compensated with the other method, and further a series of methods for determining the equal-angle division angle are perfected.

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 determining an equal angle division angle based on the sum of unit angular distance ratios of orthodontic arch wire bending points;

fig. 2 is a schematic diagram of distribution of individual orthodontic arch wire bending points and calculation of unit bending point density;

fig. 3 is a schematic diagram of equal angle initial division based on the sum of unit angular distance ratios of orthodontic arch wire bending points;

FIG. 4 is a schematic diagram of equal angle division completion and division angle determination based on orthodontic arch wire bending point unit angular distance ratio sum

The specific implementation mode is as follows:

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.