阅读说明：本技术 一种磨抛接触力实时规划方法及系统 (Grinding and polishing contact force real-time planning method and system ) 是由 杨吉祥 李鼎威 陈霖 谭超 赵欢 丁汉 于 2019-09-20 设计创作，主要内容包括：本发明属于磨抛接触力控制领域,并公开了一种磨抛接触力实时规划方法及系统,其根据材料去除模型及接触应力与接触力的关系式确定接触力初始规划模型；再确定接触面积与接触力的关系式及接触时间与刀具中心点速度的关系式；然后将两个关系式代入接触力初始规划模型中化简获得与待磨抛工件曲率相关的接触力规划模型；最后实时计算用于执行磨抛动作的刀具中心点走过的弧长,并根据刀具中心点轨迹弧长与待磨抛工件截面点曲率的映射关系确定对应的曲率,将该曲率代入接触力规划模型中计算获得对应的接触力,以此完成磨抛接触力的实时规划。本发明具有操作方便,可控性强等优点,适用于复杂自由曲面零件的磨抛接触力自动规划,实现自动化磨抛。(The invention belongs to the field of grinding and polishing contact force control, and discloses a grinding and polishing contact force real-time planning method and a grinding and polishing contact force real-time planning system, wherein a contact force initial planning model is determined according to a material removal model and a relation between contact stress and contact force; determining a relational expression of the contact area and the contact force and a relational expression of the contact time and the speed of the central point of the cutter; then substituting the two relational expressions into a contact force initial planning model for simplification to obtain a contact force planning model related to the curvature of the workpiece to be polished; and finally, calculating the arc length of the center point of the tool for executing grinding and polishing actions in real time, determining the corresponding curvature according to the mapping relation between the arc length of the path of the center point of the tool and the curvature of the cross section point of the workpiece to be ground and polished, and substituting the curvature into a contact force planning model to calculate and obtain the corresponding contact force so as to finish the real-time planning of the grinding and polishing contact force. The method has the advantages of convenience in operation, strong controllability and the like, is suitable for automatic planning of the grinding and polishing contact force of the complex free-form surface part, and realizes automatic grinding and polishing.)

1. A grinding and polishing contact force real-time planning method is characterized by comprising the following steps:

s1, determining a contact force initial planning model according to the material removal model and the relation between the contact stress and the contact force:wherein F is the contact force, psi is the material removal per unit contact area, A_cIs the contact area, k_wFor material removal coefficient, V_rThe linear speed of the cutter is shown, and T is the contact time;

s2 determining the contact area A_cRelation with contact force F, contact time T and tool center point speed V_cThe relational expression of (1);

s3 area A of contact_cRelation with contact force F, contact time T and tool center point speed V_cSubstituting the relation into a contact force initial planning model to simplify and obtain a contact force planning model related to the curvature of the workpiece to be polished;

s4, calculating the arc length of the tool center point for executing grinding and polishing actions in real time, determining the corresponding curvature according to the mapping relation between the arc length of the tool center point track and the curvature of the cross section point of the workpiece to be ground and polished, and substituting the curvature into the contact force planning model to calculate and obtain the corresponding contact force so as to complete the real-time planning of the grinding and polishing contact force.

2. The method for real-time planning of polishing contact force according to claim 1, wherein the contact area a is the contact area a_cThe relation with the contact force F is specifically as follows:

whereinF is contact force, S is tool width, v₁Is the Poisson ratio, v, of the tool₂As the poisson ratio of the part, E₁As the elastic coefficient of the tool, E₂Is the coefficient of elasticity, R, of the part₁And p is the radius of the cutter, and the curvature corresponding to the cross section point of the workpiece to be polished.

3. The method for real-time planning of contact force of polishing and grinding as claimed in claim 1, wherein the contact time T and the tool center point velocity V_cThe relation of (a) is specifically:

wherein r is_cIs the radius of curvature of the center point of the tool, S is the width of the tool, V_cThe speed of the center point of the cutter is shown, and r is the curvature radius corresponding to the cross section point of the workpiece to be ground and polished.

4. The method for real-time planning of contact force of grinding and polishing as claimed in claim 3, wherein the radius of curvature r of the center point of the tool_cThe method comprises the following steps:

when the contact surface of the cutter and the workpiece is a convex curved surface, r_c＝r+R₁；

When the contact surface of the cutter and the workpiece is a convex curved surface, r_c＝r-R₁；

When the contact surface of the cutter and the workpiece is a plane, r_cR is the curvature radius corresponding to the cross section point of the workpiece to be polished, R₁Is the tool radius.

5. The method for real-time planning of contact force of polishing and grinding as claimed in claim 2, wherein the curvature ρ corresponding to the cross-sectional point of the workpiece to be polished is represented by the formulaThe positive and negative values are determined by the included angle theta between the first normal vector and the second normal vector, wherein the first normal vector is the workpiece to be polishedThe second normal vector is a normal vector of the curvature circle center of the cross section point of the workpiece to be polished pointing to the cross section point of the workpiece.

6. A method for real-time planning of contact force of polishing and grinding as claimed in claim 5, wherein the angle θ between the first normal vector and the second normal vector is calculated by the following formula:

wherein, T_n1Is a first normal vector, T_n2Is the second normal vector.

7. A method for real-time planning of contact force of grinding and polishing according to any of claims 1-6, characterized in that the arc length travelled by the center point of the tool is calculated using the following formula:

L_k＝l₂+…+l_i+…+l_k

wherein L is_kIs the 1 st point t on the path of the center point of the cutter₁And the k-th point t_kArc length between, /)₂Is the 1 st point t on the path of the center point of the cutter₁And point 2 t₂Arc length between, /)_iIs the i-1 st point t on the path of the center point of the cutter_i-1And the ith point t_iArc length between, /)_kIs the k-1 st point t on the central point track of the cutter_k-1And the k-th point t_kThe arc length in between.

8. The grinding and polishing contact force real-time planning system is characterized by comprising the following modules:

the initial planning model determining module is used for determining a contact force initial planning model according to the material removal model and a relation between contact stress and contact force:wherein F is the contact force, psi is the material removal per unit contact area, A_cTo connect toContact area, k_wFor material removal coefficient, V_rThe linear speed of the cutter is shown, and T is the contact time;

a relational expression determination module for determining the contact area A_cRelation with contact force F, contact time T and tool center point speed V_cThe relational expression of (1);

a contact force planning model generation module for generating a contact area A_cRelation with contact force F, contact time T and tool center point speed V_cSubstituting the relation into a contact force initial planning model to simplify and obtain a contact force planning model related to the curvature of the workpiece to be polished;

and the contact force real-time planning module is used for calculating the arc length of the center point of the tool for executing grinding and polishing actions in real time, determining the corresponding curvature according to the mapping relation between the arc length of the center point track of the tool and the curvature of the cross section point of the workpiece to be ground and polished, and substituting the curvature into the contact force planning model to calculate and obtain the corresponding contact force so as to finish the real-time planning of the grinding and polishing contact force.

9. The system for real-time polishing contact force planning of claim 8 wherein said relational expression determining module determines the contact area a using the formula_cRelation to contact force F:

wherein F is the contact force, S is the cutter width, v₁Is the Poisson ratio, v, of the tool₂As the poisson ratio of the part, E₁As the elastic coefficient of the tool, E₂Is the coefficient of elasticity, R, of the part₁And p is the radius of the cutter, and the curvature corresponding to the cross section point of the workpiece to be polished.

10. The system for real-time planning of contact force of polishing and grinding of claim 8 wherein the relational expression determining module determines contact time T and tool center point velocity V using the formula_cThe relation of (1):

wherein r is_cIs the radius of curvature of the center point of the tool, S is the width of the tool, V_cThe speed of the center point of the cutter is shown, and r is the curvature radius corresponding to the cross section point of the workpiece to be ground and polished.

Technical Field

The invention belongs to the field of grinding and polishing contact force control, and particularly relates to a grinding and polishing contact force real-time planning method and system.

Background

With the development of science and technology, the application of the complex curved surface in the fields of aerospace, automobiles, ships and the like is increasingly wide. The curved surfaces cannot be composed of primary analytical curved surfaces, and an accurate analytical solution of a free complex curved surface is difficult to obtain, so that the finish machining of the complex curved surface is a manufacturing difficult problem to be solved urgently.

At present, the surface finish machining of the free-form curved surface mainly comprises a numerical control polishing technology and a manual grinding mode. The numerical control polishing technology has the defects of high price and poor universality of a numerical control machine, the labor intensity of manual polishing is high, the processing efficiency is low, the working environment is severe, meanwhile, the precision of a workpiece is greatly influenced by the skill level of workers, the consistency of the removal amount of materials is poor, and the surface quality of the workpiece is severely limited. Compared with the traditional processing mode, the robot system has the advantages of good flexibility, strong universality, easiness in expansion and the like, so that the robot system is widely applied to the field of grinding and polishing, and the contact force of the robot system needs to be planned and designed in order to realize effective grinding and polishing of workpieces.

Disclosure of Invention

Aiming at the defects or the improvement requirements of the prior art, the invention provides a grinding and polishing contact force real-time planning method and a grinding and polishing contact force real-time planning system.

In order to achieve the above object, according to one aspect of the present invention, a method for real-time planning of polishing contact force is provided, which comprises the following steps:

s1, determining a contact force initial planning model according to the material removal model and the relation between the contact stress and the contact force:wherein F is the contact force, psi is the material removal per unit contact area, A_cIs the contact area, k_wFor material removal coefficient, V_rThe linear speed of the cutter is shown, and T is the contact time;

s2 determining the contact area A_cRelation with contact force F, contact time T and tool center point speed V_cThe relational expression of (1);

s3 area A of contact_cRelation with contact force F, contact time T and tool center point speed V_cSubstituting the relation into a contact force initial planning model to simplify and obtain a contact force planning model related to the curvature of the workpiece to be polished;

s4, calculating the arc length of the tool center point for executing grinding and polishing actions in real time, determining the corresponding curvature according to the mapping relation between the arc length of the tool center point track and the curvature of the cross section point of the workpiece to be ground and polished, and substituting the curvature into the contact force planning model to calculate and obtain the corresponding contact force so as to complete the real-time planning of the grinding and polishing contact force.

More preferably, the contact area a_cThe relation with the contact force F is specifically as follows:

wherein F is the contact force, S is the cutter width, v₁Is the Poisson ratio, v, of the tool₂As the poisson ratio of the part, E₁As the elastic coefficient of the tool, E₂Is the coefficient of elasticity, R, of the part₁Is the radius of the tool, and rho is the cross section of the workpiece to be polishedThe curvature of the point correspondences.

Preferably, the contact time T and the tool center point speed V_cThe relation of (a) is specifically:

wherein r is_cIs the radius of curvature of the center point of the tool, S is the width of the tool, V_cThe speed of the center point of the cutter is shown, and r is the curvature radius corresponding to the cross section point of the workpiece to be ground and polished.

Further preferably, the tool center point radius of curvature r_cThe method comprises the following steps:

when the contact surface of the cutter and the workpiece is a convex curved surface, r_c＝r+R₁；

When the contact surface of the cutter and the workpiece is a convex curved surface, r_c＝r-R₁；

When the contact surface of the cutter and the workpiece is a plane, r_cR is the curvature radius corresponding to the cross section point of the workpiece to be polished, R₁Is the tool radius.

Preferably, the curvature rho corresponding to the cross-section point of the workpiece to be polished is represented by the formulaAnd calculating to obtain the positive and negative values of the workpiece, and determining the positive and negative values of an included angle theta between a first normal vector and a second normal vector, wherein the first normal vector is a unit normal vector of the path of the cross section point of the workpiece to be polished pointing to the center point of the tool, and the second normal vector is a normal vector of the curvature circle center of the cross section point of the workpiece to be polished pointing to the cross section point of the workpiece.

Preferably, the angle θ between the first normal vector and the second normal vector is calculated by the following formula:

wherein, T_n1Is a first normal vector, T_n2Is the second methodAnd (5) vector quantity.

As a further preferred, the arc length traveled by the center point of the tool is calculated using the following formula:

L_k＝l₂+…+l_i+…+l_k

wherein L is_kIs the 1 st point t on the path of the center point of the cutter₁And the k-th point t_kArc length between, /)₂Is the 1 st point t on the path of the center point of the cutter₁And point 2 t₂Arc length between, /)_iIs the i-1 st point t on the path of the center point of the cutter_i-1And the ith point t_iArc length between, /)_kIs the k-1 st point t on the central point track of the cutter_k-1And the k-th point t_kThe arc length in between.

According to another aspect of the invention, a grinding and polishing contact force real-time planning system is provided, which comprises the following modules:

the initial planning model determining module is used for determining a contact force initial planning model according to the material removal model and a relation between contact stress and contact force:wherein F is the contact force, psi is the material removal per unit contact area, A_cIs the contact area, k_wFor material removal coefficient, V_rThe linear speed of the cutter is shown, and T is the contact time;

a relational expression determination module for determining the contact area A_cRelation with contact force F, contact time T and tool center point speed V_cThe relational expression of (1);

a contact force planning model generation module for generating a contact area A_cRelation with contact force F, contact time T and tool center point speed V_cSubstituting the relation into a contact force initial planning model to simplify and obtain a contact force planning model related to the curvature of the workpiece to be polished;

and the contact force real-time planning module is used for calculating the arc length of the center point of the tool for executing grinding and polishing actions in real time, determining the corresponding curvature according to the mapping relation between the arc length of the center point track of the tool and the curvature of the cross section point of the workpiece to be ground and polished, and substituting the curvature into the contact force planning model to calculate and obtain the corresponding contact force so as to finish the real-time planning of the grinding and polishing contact force.

Further preferably, the relational expression determination module determines the contact area a using the following formula_cRelation to contact force F:

wherein F is the contact force, S is the cutter width, v₁Is the Poisson ratio, v, of the tool₂As the poisson ratio of the part, E₁As the elastic coefficient of the tool, E₂Is the coefficient of elasticity, R, of the part₁And p is the radius of the cutter, and the curvature corresponding to the cross section point of the workpiece to be polished.

Preferably, the relational expression determining module determines the contact time T and the tool center point speed V by using the following formula_cThe relation of (1):

wherein r is_cIs the radius of curvature of the center point of the tool, S is the width of the tool, V_cThe speed of the center point of the cutter is shown, and r is the curvature radius corresponding to the cross section point of the workpiece to be ground and polished.

Generally, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

1. according to the method, the initial planning model of the contact force is constructed through the material removal model and the relation between the contact stress and the contact force, so that direct influence factors influencing the contact force can be obtained, and then the values of the influence factors are controlled or measured to further calculate the corresponding contact force.

2. The contact force planning model is constructed based on the relation between the contact area and the contact force, the relation between the contact time and the speed of the central point of the cutter and the contact force initial planning model, the contact force planning model is related to the curvature of the workpiece to be polished, and the corresponding contact force can be calculated and obtained by obtaining the curvature of the workpiece to be polished.

3. The method determines the corresponding curvature through the mapping relation between the arc length of the central point track of the cutter and the curvature of the cross section point of the workpiece to be ground and polished, has the advantages of real-time convenience, reusability of curvature data, great reduction of workload and improvement of processing efficiency.

Drawings

Fig. 1 is a block flow diagram of a method for real-time planning of polishing contact force according to an embodiment of the present invention;

FIG. 2 is a schematic view showing the judgment of a convex curved surface and a concave curved surface;

FIG. 3 is a schematic of the tool center point speed and the touch speed;

FIG. 4 is a schematic view of the curved surface contact of the tool and the workpiece.

The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein:

1-cutter, 2-workpiece curved surface.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 1, an embodiment of the present invention provides a method for real-time planning of polishing contact force, which includes the following steps:

s1, first, a contact force initial planning model is determined according to the material removal model and the relation between the contact stress and the contact force, specifically, the material removal model is as follows:

and contact stress p_cThe contact force F is related toComprises the following steps:

thus, it is possible to obtain:

wherein F is the contact force and psi is the material removal per unit contact area (g/mm)²) (the amount of material removed per point is different, which is a predetermined parameter), A_cIs the contact area, k_wFor removing coefficients of material (preset, e.g. 1X 10)^-9)，V_rFor linear speed (m/s, preset, e.g. 2m/s) of the tool (e.g. grinding head), T is contact time, p_cIs contact stress (MPa);

s2 determining the contact area A_cRelation with contact force F, contact time T and tool center point speed V_cThe relational expression of (1);

specifically, the contact area A_cThe relationship with contact force F is:

wherein F is the contact force, S is the cutter width, v₁Is the Poisson ratio, v, of the tool₂As the poisson ratio of the part, E₁As the elastic coefficient of the tool, E₂Is the coefficient of elasticity, R, of the part₁The radius of the cutter is defined, and rho is the curvature corresponding to the cross section point of the workpiece to be polished;

contact time T and tool center point velocity V_cThe relation of (A) is as follows:

wherein r is_cIs the radius of curvature of the center point of the tool, S is the width of the tool, V_cThe speed of the center point of the cutter is used, and r is the curvature radius corresponding to the cross section point of the workpiece to be ground and polished;

s3 area A of contact_cRelation with contact force F, contact time T and tool center point speed V_cSubstituting the relation into the contact force initial planning model to simplify and obtain the contact force planning model related to the curvature of the workpiece to be polished:

s4, calculating the arc length of the tool center point for executing grinding and polishing actions in real time, determining the corresponding curvature according to the mapping relation between the arc length of the tool center point track and the curvature of the cross section point of the workpiece to be ground and polished, and substituting the curvature into the contact force planning model to calculate and obtain the corresponding contact force so as to complete the real-time planning of the grinding and polishing contact force.

Further, the contact area A_cThe relation to the contact force F is determined as follows:

specifically, the contact area A_cThe following relationship exists with respect to the tool width S:

A_c＝2b_cS

wherein the content of the first and second substances,

b is to_cSubstitution of w and Δ into A_c＝2b_cS is simplified to obtain:

wherein, b_cThe contact area half width, w is the stress per unit length (median), R₁Is the radius of the tool (measured), v₁Is the tool Poisson ratio (measured), v₂For the Poisson's ratio of the part (measured), E₁As the elastic coefficient (measured) of the tool, E₂The part spring constant (measured), S the tool width (measured) and F the contact force.

Further, the contact time T and the tool center point velocity V_cIs determined in the following manner:

first, a contact velocity V is established_tContact time T model:

wherein T is the contact time, b_cIs half-width of contact surface, V_tFor the contact velocity, A_cIs the contact area and S is the tool width.

Then, establishing a model between the contact velocity and the tool center point velocity:

V_t＝W_t*r

V_c＝W_c*r_c

W_t＝W_c

wherein, V_tFor contact velocity, V_cIs the speed of the center point of the tool, W_tFor cutting the angular velocity, W_cThe angular velocity of the center point of the tool, r is the contact curvature radius (i.e. the curvature radius r corresponding to the cross-section point of the workpiece), r_cThe radius of curvature of the center point of the cutter;

finally, the relation between the contact time and the speed of the center point of the tool (namely, the relation between the contact time and the speed of the center point of the tool) is calculated according to the contact speed and contact time model and the contact speed and speed model of the center point of the toolSubstitution intoThe following are added:

more specifically, the radius of curvature r of the center point of the tool_cThe method comprises the following steps:

when the contact surface of the cutter and the workpiece is a convex curved surface, r_c＝r+R₁；

When the contact surface of the cutter and the workpiece is a convex curved surface, r_c＝r-R₁；

When the contact surface of the cutter and the workpiece is a plane, r_cR is the curvature radius corresponding to the cross section point of the workpiece to be polished, R₁Is the tool radius.

Furthermore, the size of the curvature rho corresponding to the cross section point of the workpiece to be polished is represented by a formulaAnd calculating, and judging whether the curvature is positive or negative through an included angle theta between a first normal vector and a second normal vector, wherein the first normal vector is a unit normal vector of the cross section point of the workpiece to be polished pointing to the center point track of the tool, and the second normal vector is a normal vector of the center point of the curvature of the cross section point of the workpiece to be polished pointing to the cross section point of the workpiece. Specifically, when the curvature is 0 (i.e., r is infinite), the positive/negative determination is not required, and the contact surface is a plane, and when the curvature is not 0, the positive/negative determination is performed.

Wherein the first normal vector T_n1The calculation formula of (a) is as follows:

T_t＝[T_x，T_y]

T_n1＝[-T_y，T_x]

second normal vector T_n2The calculation formula of (a) is as follows:

T_n2＝(x,y)-(x_c,y_c)

the calculation formula of the included angle theta between the two vectors is as follows:

wherein, T_tIs a unit tangent vector of the cross section of the workpiece, T_xIs a unit tangent vector abscissa, T, of the cross section of the workpiece_yIs the ordinate of the unit tangent vector of the cross section of the workpiece, x, y are the abscissa and the ordinate of the point on the cross section of the workpiece, x_c,y_cIs the coordinate of the center point of curvature of the cross section of the workpiece, and theta is the included angle between the first normal vector and the second normal vector.

When θ is equal to 0, it means that the first normal vector and the second normal vector are in the same direction, the contact surface is a convex curved surface, and the curvature is positive, that is, the contact surface is a curved surfaceIf theta is equal to pi, the first normal vector and the second normal vector are opposite, the contact surface is a concave curved surface, and the curvature is negative, namely

In addition, the arc length traveled by the center point of the tool is calculated by the following formula:

L_k＝l₂+…+l_i+…+l_k

wherein L is_kIs the 1 st point t on the path of the center point of the cutter₁And the k-th point t_kArc length between, /)₂Is the 1 st point t on the path of the center point of the cutter₁And point 2 t₂Arc length between, /)_iIs the i-1 st point t on the path of the center point of the cutter_i-1And the ith point t_iThe arc length between (i is more than or equal to 2 and less than or equal to k), l_kIs the k-1 st point t on the central point track of the cutter_k-1And the k-th point t_kThe arc length in between.

Specifically, the method comprises the following steps:

wherein the content of the first and second substances,is the first point t on the path of the center point of the tool₁Is determined by the coordinate of (a) in the space,is a second point t on the path of the center point of the tool₂Is determined by the coordinate of (a) in the space,is the ith point t on the path of the center point of the cutter_iIs determined by the coordinate of (a) in the space,is the i-1 st point t on the path of the center point of the cutter_i-1Is determined by the coordinate of (a) in the space,is the kth point t on the path of the center point of the tool_kIs determined by the coordinate of (a) in the space,is the k-1 st point t on the central point track of the cutter_k-1The coordinates of (a).

The following mapping relationship exists between points on the path of the center point of the cutter and points on the section of the workpiece:

(x_t,y_t)＝(x,y)+R₁·T_n1

wherein x is_t,y_tIs the abscissa and ordinate of a point on the path of the center point of the tool, x, y are the abscissa and ordinate of the corresponding point on the cross-section of the workpiece, R₁Is a cutter halfDiameter, T_n1Is the first normal vector.

Because the starting point of the tool is known, the current position of the tool (for example, the position of the second point on the tool center point track) is measured in real time, that is, the arc length of the tool center point track can be obtained by calculating the coordinates of the starting point and the current position, and because the point on the tool center point track and the point on the workpiece section have a one-to-one mapping relation, the corresponding point on the workpiece section can be determined by the coordinates of the second point, and the corresponding point on the workpiece section is known (the parameters corresponding to each point are known, including the material removal psi, the curvature rho, the curvature radius r and the tool center point speed V of the unit contact area_cLinear velocity V of cutting tool_rEtc.) to know the curvature rho of the point, and substituting the curvature rho into a contact force planning model related to the curvature of the workpiece to be polishedIn the method, the corresponding contact force can be calculated, wherein psi and V_c、V_rAnd k_wPreset, S, v₁、v₂、E₁、E₂、R₁And r are known parameters, r_cAnd (6) calculating.

For example, the 1 st point t on the path of the center point of the tool is known₁And point 2 t₂Coordinates of (2), i.e. by formulaCalculating the 1 st point t on the path of the center point of the cutter₁And point 2 t₂Arc length between is l₂2 nd point t₂The coordinates of the point t and the 2 nd point t on the cross section of the workpiece can be obtained according to the mapping relation₂And after the corresponding point is confirmed, the parameters such as curvature, curvature radius, material removal amount and the like can be known, and the rest points are analogized in turn.

That is, the arc length between two points on the tool center point trajectory has a mapping relation with the curvature ρ, the curvature radius r and the material removal amount ψ:

wherein the content of the first and second substances,is the 1 st point t on the path of the center point of the cutter₁Curvature of r₁Is the 1 st point t on the path of the center point of the cutter₁The radius of curvature of (a) is,is the 1 st point t on the path of the center point of the cutter₁The amount of material to be removed of (c),is the kth point t on the path of the center point of the tool_kCurvature of r_kIs the kth point t on the path of the center point of the tool_kThe radius of curvature of (a) is,is the kth point t on the path of the center point of the tool_kAmount of material removal.

Namely, the arc length between two points on the central point track of the cutter is known, so that the corresponding curvature rho, curvature radius r and material removal amount psi can be known, and the corresponding contact force corresponding to the current point can be calculated by substituting the curvature radius r and the material removal amount psi into a contact force planning model, namely, the arc length and the contact force have a one-to-one mapping relation. The prior art generally determines the corresponding curvature directly through mapping the coordinate points with the curvature, the curvature radius and the material removal amount, and has the following disadvantages (for example, machining the blade, as shown in fig. 4): the workpiece is provided with a plurality of blades, the shape of each blade is the same, the coordinates of the tool center point track of each blade are different through coordinate mapping, each blade needs to be mapped independently, and the workload is large. The invention determines the corresponding curvature through the mapping relation of the arc length and the curvature, the curvature radius and the material removal amount, and has the advantages that the shape of each processed blade is the same, and the arc length of the center point of the cutter is also the same, so the mapping workload according to the arc length is much smaller, when the mapping relation of the arc length and the curvature, the curvature radius and the material removal amount of one blade is determined, the mapping data (the arc length and the contact force are mapped one by one) of the first blade is only needed to be called when the other blades are ground and polished, and the mapping and calculation are not needed to be carried out one by one, for example, when the second blade is processed (the processing starting point and the track are the same as the first blade), the arc length is measured in real time, the corresponding contact force is directly selected from the mapping data of the first blade according to the arc length, and the mapping matching of the point on the section of the workpiece and the, and the corresponding curvature is obtained again, and the contact force is calculated again, so that the efficiency can be greatly improved.

In addition, the invention also provides a grinding and polishing contact force real-time planning system, which comprises the following modules:

an initial planning model determining module for determining a contact force initial planning model according to the material removal model and the relation between the contact stress and the contact force

A relational expression determination module for determining the contact area A_cRelation with contact force F, contact time T and tool center point speed V_cThe relational expression of (1);

a contact force planning model generation module for generating a contact area A_cRelation with contact force F, contact time T and tool center point speed V_cSubstituting the relation into a contact force initial planning model to simplify and obtain a contact force planning model related to the curvature of the workpiece to be polished;

and the contact force real-time planning module is used for calculating the arc length of the center point of the tool for executing grinding and polishing actions in real time, determining the corresponding curvature according to the mapping relation between the arc length of the center point track of the tool and the curvature of the cross section point of the workpiece to be ground and polished, and substituting the curvature into the contact force planning model to calculate and obtain the corresponding contact force so as to finish the real-time planning of the grinding and polishing contact force.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.