CN104888999B - A kind of variable spray gun coating sedimentation model modeling method - Google Patents

Abstract

The invention discloses a modeling method of a variable spray gun paint deposition model. The variable spray gun paint deposition model established by the invention can be widely used in variable spraying operations of spraying robots with complex free-form surfaces, and is comparable to the traditional spray gun paint deposition model modeling method. Compared, when changing spray gun spraying height and spraying inclination angle in the spraying process, do not need to repeatedly do spraying experiment to set up spraying gun coating deposition model, use the model that the method of the present invention establishes to be able to predict the spraying gun coating deposition under different spraying gun parameters rapidly model, which effectively improves the spraying efficiency.

Description

A modeling method of variable spray gun paint deposition model

technical field

The invention relates to a deposition model modeling method, in particular to a variable spray gun coating deposition model modeling method.

Background technique

Due to the advantages of high spraying quality, low labor intensity and liberating workers from toxic environment, the off-line programming control method of spraying robot is more and more used in fields such as automobiles, ships and aerospace.

The modeling of robot spray gun coating deposition model is the key technical problem to be solved first in the construction of robot spraying off-line programming system. The traditional modeling method is only based on the premise of constant spray gun parameters, combined with static spraying experiments to complete the modeling, and the obtained spray gun coating deposition model It does not adapt to the requirements of the variable spraying process, such as changing the spraying height and changing the spraying angle during the spraying process, and cannot handle the spraying operations with complex free-form surfaces.

Contents of the invention

The purpose of the present invention is to provide a modeling method for variable spray gun paint deposition model, aiming at the needs of variable spray coating process, with spray height and spray angle as controllable variables, to realize fast and accurate modeling of variable spray gun paint deposition model, and finally to use The rapid acquisition of spray gun paint deposition model by robot variable spraying trajectory planning realizes the application of spray gun paint deposition model in variable automatic spraying.

The technical scheme of the present invention is: a kind of modeling method of variable spray gun paint deposition model, specifically comprises the following steps:

1) Determine the fan angle of the spray gun torch and the spraying height range, use the limited range model to simulate the deposition distribution of the spray gun coating on the flat plate, and do the vertical static spraying experiment of the spray gun on the flat plate with the standard spraying height per unit time. Inside, measure along the radial direction to obtain the coating thickness of several discrete points, and fit to obtain the initial spray gun coating deposition model during vertical spraying at the standard spraying height;

2) Based on the above-mentioned initial spray gun paint deposition model, use the differential geometric amplification theorem to establish a spray gun paint deposition theory model with the spray angle and spray height as variables;

3) Change the spraying height within the allowable range of the spraying height, and do a series of spraying experiments with the spray gun at a static angle on the flat plate under the condition of constant spraying height, measure the coating thickness of discrete points within the coating deposition range, and use the spraying angle The theoretical model of spray gun coating deposition with spraying height as variables is fitted to the coating thickness of a series of discrete points respectively, and the correction coefficient values of a series of models are obtained, and the correction coefficient of the model is established with the change of spraying inclination angle and spraying height by binary function fitting. The law model is used to correct the above theoretical model, so as to establish the spray gun paint deposition model with the spraying angle and spraying height as variables.

As preferred technical scheme, described step 1) in the modeling method of initial spray gun coating deposition model, specifically comprise the steps:

(1) Establish a Cartesian coordinate system with the center of the circular paint coverage as the coordinate origin, and make a series of circle diameter lines through the center of the circle to ensure that the angles between adjacent diameter lines are equal; draw a circle within the circular paint coverage A series of concentric circles to ensure that the line segments divided by these concentric circles are equal to the diameter line, and the intersection of the diameter line and the concentric circles is the measurement point;

(2) Measure the coordinates and coating thickness corresponding to the measurement points respectively, denoted as q _ij , where ij represents the jth measurement point on the i-th concentric circle, there are N concentric circles, and each concentric circle has M measuring points, take the average value of the coating thickness of the measuring points on each concentric circle, recorded as

(3) Suppose the finite range model used for fitting is q(r), r∈[-Htan(θ/2),-Htan(θ/2)], where θ represents the vertex angle of the spray gun torch fan angle, H represents the spraying height, and the fitting optimization function is established by using the least square method:

Relevant parameters of the initial spray gun paint deposition model are obtained by solving, so as to establish the initial spray gun paint deposition model, denoted as q ₁ (r).

As preferred technical scheme, described step 2) is the spray gun coating deposition theoretical model of variable with spraying inclination angle and spraying height, and its concrete model is as follows:

in: H _S =H+x sinα;

r _S is the vertical distance from a point on the line passing through the point S and the nozzle to the origin O;

λ is the angle between the axis of the spray gun and the line connecting the point S to the origin O;

H _S is the distance between the nozzle and point S projected on the spray gun axis, and H is the spray height when the spray gun is still spraying;

α represents the angle between the spray gun axis and the plane normal, and A(H, α) represents the model correction function related to the spraying height and spraying inclination.

As preferred technical scheme, in described step 3), the specific method of setting up the spray gun paint deposition model with spraying height and spraying inclination as variable is as follows:

(1) Let the range of spraying inclination α be [0, α _max ], and the range of spraying height H be [H _min , H _max ], and take different spraying heights within this range [H ₁ , H ₂ , ..., H _s ] Do the spraying experiments with different spraying angles [α ₁ , α ₂ ,..., α _t ] in sequence, and measure the coating thickness at discrete points within the coating coverage range, q _ijk represents the spraying gun at the spraying height of H _i The coating thickness of the kth point within the coating coverage range when the inclination angle is _αj ;

(2) Based on the established theoretical model of spray gun coating deposition considering the spraying angle and spraying height as variables, the least square method is used to fit the coating thickness at discrete points measured after each experiment, and the fitting function matrix is obtained as follows:

(3) By solving the above fitting function matrix, the model correction coefficient matrix is obtained as:

Where A _ij represents the correction coefficient value of the spray gun coating deposition model when the spray gun inclination angle is α _j at the spraying height of H _i ;

(4) With the spraying height H _i and spraying inclination α _j as variables, and A _ij as a function, use the binary function surface fitting method to fit them, and obtain the correction coefficient model A(H, α), so as to establish the spraying A spray gun paint deposition model with variables for inclination angle and spray height.

As a preferred technical scheme, the fan angle of the spray gun torch described in step 1) is aimed at the spray gun that the coating space is distributed as conical;

The spraying height refers to the distance from the axis of the spray gun to the surface of the workpiece to be sprayed, and the spraying height range refers to the adjustable spraying height range to ensure the coating effect;

The limited range model refers to a mathematical function expression assuming that the coating thickness outside the fan angle of the torch of the spray gun is zero.

As a preferred technical solution, the limited range model is a β distribution model, a Gaussian sum model or a piecewise function model.

The advantages of the present invention are: the variable spray gun paint deposition model established by the present invention can be widely used in the variable spraying operations of spraying robots with complex free-form surfaces. Compared with the traditional spray gun paint deposition model modeling method, when the spray gun spraying process is changed Height and spraying inclination, do not need to repeatedly do spraying experiments to establish a spray gun coating deposition model, use the model established by the method of the present invention to quickly predict the spray gun coating deposition model under different spray gun parameters, effectively improving the spraying efficiency.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment:

Fig. 1 is the modeling flowchart of variable spray gun paint deposition model;

Figure 2 is a discrete schematic diagram of the measurement points in the spraying area of the vertical spraying experiment;

Fig. 3 is the schematic diagram of spray gun spraying space model;

Fig. 4 is the discrete schematic diagram of measuring points in the spraying area of the inclination spraying experiment;

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:

A variable spray gun coating deposition model modeling method specifically includes the following steps:

Step 1) Under the premise of ensuring that the spray gun spraying can obtain a good spraying effect, measure the fan angle of the spray gun torch and the spraying height range, use the limited range model to simulate the deposition distribution of the spray gun coating on the flat plate, and use the standard spraying height on the flat plate Do the vertical static spraying experiment of the spray gun per unit time, measure the coating thickness of several discrete points along the radial direction within the circular coating coverage area, and obtain the initial spray gun coating deposition model when vertical spraying at the standard spraying height by fitting;

The specific method of the above-mentioned spray gun vertical static spraying experiment is as follows:

(1) For a type of spray gun, measure the torch fan angle θ and the spray height range [H _min , H _max ] when the spray gun can spray normally;

(2) Determine the finite range model for simulating the distribution of paint on the plane. The finite range model is a β distribution model, a Gaussian sum model or a piecewise function model, etc. Here, the widely used β distribution model is taken as an example, and its expression as follows:

(3) Do a static spraying experiment with the spray gun per unit time on the flat plate at a standard spraying height, usually with 1s as the time unit.

The spray torch fan angle of the spray gun is aimed at the spray gun whose paint space distribution is conical; the spray height refers to the distance from the axis of the spray gun to the surface of the workpiece to be sprayed, and the spray height range refers to the adjustable distance to ensure the coating effect. Spraying height range; the limited range model refers to a mathematical function expression that assumes that the coating thickness outside the fan angle of the spray gun torch is 0.

The modeling method of the above-mentioned initial spray gun paint deposition model specifically includes the following steps:

(1) After the spraying experiment, after the paint dries, establish a Cartesian coordinate system with the center of the circular paint coverage as the coordinate origin, as shown in Figure 2, and draw a series of circle diameter lines through the center of the circle to ensure that adjacent diameter lines The angles between them are equal; make a series of concentric circles within the coverage of the circular paint to ensure that the concentric circles divide the diameter lines into equal segments, and the intersection of the diameter line and the concentric circles is the measurement point;

(2) Measure the coordinates and coating thickness corresponding to the measurement points respectively, denoted as q _ij , where ij represents the jth measurement point on the i-th concentric circle, there are N concentric circles, and each concentric circle has M measuring points, take the average value of the coating thickness of the measuring points on each concentric circle, recorded as

(3) Suppose the finite range model used for fitting is q(r), r∈[-Htan(θ/2),-Htan(θ/2)], where θ represents the vertex angle of the spray gun torch fan angle, H represents the spraying height, based on the β distribution model, the least square method is used to establish a fitting optimization function:

Solve to obtain the β value of the β distribution model, so as to establish the initial spray gun paint deposition model, denoted as q ₁ (r).

Step 2) Based on the above-mentioned initial spray gun paint deposition model, use the differential geometric amplification theorem to establish a spray gun paint deposition theoretical model with spray angle and spray height as variables, as shown in Figure 3;

The above-mentioned theoretical model of spray gun coating deposition with spraying angle and spraying height as variables, its specific model is as follows:

in: H _S =H+x sinα;

r _S is the vertical distance from a point on the line passing through the point S and the nozzle to the origin O;

λ is the angle between the axis of the spray gun and the line connecting the point S to the origin O;

H _S is the distance between the nozzle and point S projected on the spray gun axis, and H is the spray height when the spray gun is still spraying;

α represents the angle between the spray gun axis and the plane normal, and A(H, α) represents the model correction function related to the spraying height and spraying inclination.

Step 3) Change the spraying height within the allowable range of the spraying height, and do a series of spray gun static angle spraying experiments on the flat plate under the constant spraying height, measure the coating thickness of discrete points within the coating deposition range, to spray The theoretical model of spray gun coating deposition with inclination angle and spray height as variables respectively fits the coating thickness of a series of discrete points, and obtains the correction coefficient values of a series of models, and uses binary function fitting to establish a model. The correction coefficient changes with the spray inclination angle and spray height Based on the law model, the above theoretical model is corrected with this law model, so as to establish the spray gun paint deposition model with the spraying angle and spraying height as variables.

The specific method of establishing the above-mentioned spray gun paint deposition model with spray height and spray angle as variables is as follows:

(1) Let the range of spraying inclination α be [0, α _max ], and the range of spraying height H be [H _min , H _max ], and take different spraying heights within this range [H ₁ , H ₂ , ..., H _s ] Do the spraying experiments with different spraying angles [α ₁ , α ₂ , ..., α _t ] in unit time in turn, and measure the coating of the discrete points within the coating coverage area according to the method of obtaining discrete points in the spraying area shown in Figure 4 Thickness, where q _ijk represents the coating thickness of the kth point in the coating coverage when the spray gun inclination angle is α _j at the spraying height of H _i ;

(2) Based on the established theoretical model of spray gun coating deposition considering the spray angle and spray height as variables, the least square method is used to fit the coating thickness of g discrete points measured after each experiment, and the fitting function matrix is obtained as :

(3) By solving the above fitting function matrix, the model correction coefficient matrix is obtained as:

Where A _ij represents the correction coefficient value of the spray gun coating deposition model when the spray gun inclination angle is α _j at the spraying height of H _i ;

(4) With the spraying height H _i and spraying inclination α _j as variables, and A _ij as a function, use the binary function surface fitting method to fit them, and obtain the correction coefficient model A(H, α), so as to establish the spraying A spray gun paint deposition model with variables for inclination angle and spray height.

The variable spray gun paint deposition model established by the present invention can be widely used in the variable spraying operation of the spraying robot with complex free-form surfaces. Compared with the traditional spray gun paint deposition model modeling method, when the spray gun spray height and spray angle are changed during the spray process, It is not necessary to repeatedly do spraying experiments to establish a spray gun paint deposition model, and the model established by using the method of the present invention can quickly predict the spray gun paint deposition model under different spray gun parameters, effectively improving the spraying efficiency.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims (3)

1. a kind of variable spray gun coating sedimentation model modeling method, it is characterised in that specifically include following steps：

1) spray gun spray torch segment angle and spraying altitude range are determined, with finite range model simulation spray gun coating on flat board Deposition distribution rule, does the vertical static spraying experiment of unit interval spray gun, in circular coating with standard spray height on flat board In coverage, radially measurement obtains the coating layer thickness of some discrete points, and fitting obtains the highly sagging direct-injection of standard spray and applies When initial spray gun coating sedimentation model；

2) based on above-mentioned initial spray gun coating sedimentation model, amplify theorem with Differential Geometry and set up high to spray inclination angle and spraying Spend for the spray gun coating of variable deposits theoretical model；

3) change spraying height in the range of spraying height is allowed, and one is done on flat board in the case where constant height is sprayed Serial spray gun it is static inclination angle spraying experiment, in coating range of deposition measure discrete point coating layer thickness, with spray inclination angle and Spraying height is fitted the coating layer thickness of series of discrete point for the spray gun coating deposition theoretical model of variable respectively, obtains a series of The correction factor value of model, correction factor is set up with spraying inclination angle and the rule of spraying height change with binary function fitting Rule model, with this rule Modifying model above-mentioned theory model, so that it is the spray gun of variable to set up to spray inclination angle and spraying height Coating sedimentation model；

The step 1) in initial spray gun coating sedimentation model modeling method, specifically include following steps：

(1) rectangular coordinate system is set up by the origin of coordinates of the center of circle of circular coating coverage, and crosses the center of circle and make a series of circles Diameter line, it is ensured that folded angle is equal between adjacent straight radial line；Make a series of concentric circles in circular coating coverage, it is ensured that this The line segment that a little concentric circles split diameter line is impartial, and diameter line is measurement point with the intersection point of concentric circles；

(2) the corresponding coordinate of measurement point and coating layer thickness are measured respectively, are designated as q_ij, wherein ij represents the jth on i-th concentric circles Individual measurement point, is provided with N number of concentric circles, there is M measurement point on each concentric circles, and measurement point coating layer thickness is taken on each concentric circles Average value, is designated as

(3) finite range model set for being fitted is q (r), r ∈ [- H tan (θ/2) ,-H tan (θ/2)], and wherein θ is represented Spray gun sprays the drift angle of torch segment angle, and H represents spraying height, and fitting majorized function is set up with least square method：

$E_1=min\underset{i=1}{\overset{N}{\Σ}}{({\stackrel{\‾}{q}}_i-q(r\left)\right)}^2$

The relevant parameter for obtaining initial spray gun coating sedimentation model is solved, so as to set up initial spray gun coating sedimentation model, q is designated as₁ (r)。

The step 2) in spray inclination angle and spraying height be variable spray gun coating deposit theoretical model, its concrete model is such as Under：

$q_2(x,y,H,\mathrm{\α})=A(H,\mathrm{\α})q_1\left(r_S\right){\left(\frac{H}{H_S}\right)}^{2}cos\mathrm{\α};$

Wherein：H_S=H+xsin α；

r_STo cross on point S and nozzle line a little to the vertical range of origin O；

λ is the angle of spray gun axis and point S to origin O lines；

H_SIt is distance of the nozzle to point S between subpoint on spray gun axis, spraying when H is spray gun static spraying is highly；

α represents the angle between spray gun axis and plane normal direction, and A (H, α) represents the mould related to spraying height and spraying inclination angle Type correction function.

The step 3) in set up with spray height and spraying inclination angle as the spray gun coating sedimentation model of variable specific method such as Under：

(1) it is [0, α to set spraying inclination alpha scope_max], spraying height H scopes are [H_min,H_max], take difference respectively within this range Spraying height [H₁、H₂、…、H_s] take turns doing different spraying inclination angle [α₁、α₂、…、α_t] spraying experiment in the unit interval, and The coating layer thickness of measurement discrete point, q in coating coverage_ijkRepresent in H_iSpraying height under spray gun inclination angle be α_jWhen coating cover K-th point of coating layer thickness in the range of lid；

(2) based on the consideration spraying inclination angle and spraying height set up for the spray gun coating of variable deposits theoretical model, with minimum Square law is fitted to the discrete point coating layer thickness measured after experiment every time, obtains fitting function matrix and is：

(3) by solving above-mentioned fitting function matrix, obtaining correction factor matrix is：

Wherein A_ijRepresent in H_iSpraying height under spray gun inclination angle be α_jWhen spray gun coating sedimentation model correction factor value；

(4) spraying height H_iWith spraying inclination alpha_jIt is variable, A_ijIt is function, with the method for binary function surface fitting to entering Row fitting, obtains revision coefficient model A (H, α), so as to set up to spray inclination angle and spraying height for the spray gun coating of variable sinks Product module type.

2. variable spray gun coating sedimentation model modeling method according to claim 1, it is characterised in that step 1) described in Spray gun spray torch segment angle is directed to the spray gun that coating spatial distribution is cone；

The spraying height refers to distance of the spray gun axis to workpiece surface to be sprayed, and the spraying altitude range refers to ensure to apply Material covers the adjustable spraying altitude range of effect；

The finite range model refers to the mathematical function expression formula that the coating layer thickness that hypothesis spray gun is sprayed beyond torch segment angle is 0.

3. variable spray gun coating sedimentation model modeling method according to claim 2, it is characterised in that the limited range Model is β distributed models, gaussian sum model or multi-stage model.