A method and system for controlling the paint thickness of a double helix superimposed spray on the inner wall of a cylinder

Abstract

The application discloses a paint thickness control method and system for double-helix superposition spraying of a cylinder inner wall, and relates to the technical field of spraying. The method comprises the following steps: a plane translation paint film thickness distribution model is constructed, and a cylinder inner wall paint film superposition thickness distribution model is further constructed; a trajectory interval value is determined according to the cylinder inner wall paint film superposition thickness distribution model, so that the paint film thickness distribution is more uniform; and the moving speed of a spraying walking mechanism and the rotating speed of a spray gun are adjusted according to the selected trajectory interval value, the spraying distance, the spraying flow and the speed relationship between the spraying walking mechanism and the spray gun, so that the thickness of the sprayed paint film is more uniform during the spraying process. The spraying time can be shortened and the spraying efficiency can be improved by adjusting and controlling the size of the spraying flow.

Description

Technical Field

[0001] This invention relates to the field of spraying technology, and in particular to a method and system for controlling paint thickness in double-helix superimposed spraying on the inner wall of a cylinder. Background Technology

[0002] Many large cylindrical components require internal surface coating before use, and the uniformity of the coating thickness significantly affects the corrosion protection effect. Furthermore, current internal coating methods commonly use linear spraying equipment instead of spiral spraying, preventing complete coating in a single pass and resulting in prolonged spraying time and low efficiency. For spiral spraying, adjusting the spray flow rate q, spray distance h0, and the spacing d between adjacent trajectories, as well as the moving speed v of the spraying equipment and the rotation speed ω of the spray gun, are crucial for adjusting the paint thickness distribution and improving spraying efficiency. Summary of the Invention

[0003] The technical problem solved by this invention is how to adjust the spray flow rate, spray distance and adjacent trajectory spacing to change the moving speed of the spraying travel mechanism and the rotation speed of the spray gun in spiral spraying. It provides a method and system for controlling the paint thickness of double spiral superimposed spraying on the inner wall of a cylinder, which can ensure a more uniform distribution of sprayed paint thickness and improve spraying efficiency.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] In a first aspect, this application provides a method for controlling paint thickness in a double-helix superimposed spraying process on the inner wall of a cylinder, comprising:

[0006] Obtain the basic dimensional parameters of the inner wall of the cylinder and the planar fixed-point spraying properties of the spray gun;

[0007] Based on the basic dimensional parameters of the inner wall of the cylinder and the planar fixed-point spraying properties of the spray gun, the double-helix spraying paint trajectory of the spraying device is analyzed. A relationship between the trajectory spacing and the cross-sectional angle is constructed, along with a planar translational paint film thickness distribution model of the double-helix spraying paint trajectory when the spray gun moves at a constant speed along the moving direction and the paint film accumulates directionally. The double-helix spraying paint trajectory is the spraying trajectory obtained when the spraying travel mechanism moves at a constant speed along the cylinder axis on the inner wall of the cylinder, and two spray guns symmetrically mounted on the spraying travel mechanism rotate around the cylinder axis with their rotation centers coinciding with the cylinder axis. The cross-sectional angle is the angle between the linear motion trajectory obtained by shearing and unfolding the double-helix spraying paint trajectory along the cylinder axis and the cylinder cross-section.

[0008] The coating thickness distribution model of the inner wall of the cylinder is obtained based on the planar translation coating thickness distribution model.

[0009] Under various trajectory spacing values, the cylinder inner wall paint film thickness distribution model considering the paint film superposition phenomenon of adjacent trajectories is obtained by superimposing the paint film superposition model of adjacent trajectories.

[0010] The coating process parameters are adjusted according to the coating thickness distribution model of the inner wall of the cylinder and the relationship between the trajectory spacing and the cross-sectional angle to control the coating thickness of the inner wall of the cylinder to be coated; the coating process parameters include the trajectory spacing, the spraying flow rate of the spray gun, the spraying distance, the spraying rotation speed and the moving speed of the spraying travel mechanism.

[0011] Optionally, the expression for the planar translational paint film thickness distribution model is:

[0012] Q0(x)=Q max (1-4x 2 / w 2 ) β-1

[0013] Where Q0(x) represents the paint thickness distribution across the cross-section of a uniformly sprayed linear section; Q max For maximum cumulative paint thickness, A is a constant; q is the spraying flow rate; w is the spraying width; β is an undetermined parameter in the double β distribution function; x is the horizontal distance between the projection point of the spraying area point O and point M on the spraying plane; the spraying area point O is the trajectory point on the plane where the linear motion trajectory obtained by shearing and unfolding the double helix spraying paint trajectory along the cylinder axis is located; the spray gun nozzle is point M.

[0014] Optionally, the expression for the paint film thickness distribution model on the inner wall of the cylinder is:

[0015]

[0016] Where h0 is the spraying distance; h1 is the distance from point M to plane K, plane K is the plane where point O′ is located, and point O′ is the projection of point O in the spraying area onto the arc surface of the inner wall of the cylinder; tanψ=x / h0; Let be the angle formed by the normal vectors of circular surface s3 and circular surface s4; circular surface s3 is a circular surface with center O′ and normal vector pointing to point M; circular surface s4 is a circular surface with center O′ and normal vector pointing to the center of the cylindrical cross-section passing through point O′.

[0017] Optionally, the expression for the coating thickness distribution model on the inner wall of the cylinder is:

[0018]

[0019] Where d is the distance between adjacent trajectories.

[0020] Optionally, the paint thickness on the inner wall of the cylinder is controlled by adjusting the spraying process parameters according to the coating thickness distribution model of the inner wall of the cylinder and the relationship between the trajectory spacing and the cross-sectional angle. Specifically, this includes:

[0021] Determine the spraying distance of the spray gun and set different trajectory spacing values; substitute the spraying distance and each trajectory spacing value into the cylinder inner wall paint film superposition thickness distribution model to obtain the maximum and minimum values ​​of the cylinder inner wall paint film superposition thickness distribution model function curve corresponding to each trajectory spacing value;

[0022] The maximum and minimum values ​​are used to obtain the extreme value deviation corresponding to each trajectory spacing value; the trajectory spacing value corresponding to the extreme value deviation being less than the maximum allowable deviation of the actual paint film thickness is selected.

[0023] The cross-sectional angle is determined based on the selected trajectory spacing value and the relationship between the trajectory spacing and the cross-sectional angle; the velocity relationship between the moving speed and the rotating speed is determined based on the cross-sectional angle.

[0024] The moving speed of the spraying walking mechanism and the rotation speed of the spray gun are adjusted according to the selected trajectory spacing value, the spraying distance, the spraying flow rate, and the speed relationship, so that the paint film thickness of the spraying trajectory on the inner wall of the cylinder to be sprayed satisfies the paint film superposition thickness distribution model of the inner wall of the cylinder; the spraying flow rate is determined according to the preset spraying time; the spraying flow rate and the moving speed of the spraying walking mechanism are positively correlated.

[0025] Secondly, this application provides a paint thickness control system for double-helix superimposed spraying on the inner wall of a cylinder, comprising:

[0026] The basic data acquisition module is used to acquire the basic dimensional parameters of the inner wall of the cylinder and the planar fixed-point spraying attributes of the spray gun.

[0027] A planar translational paint film thickness distribution model construction module is used to analyze the double-helix paint trajectory of the spraying device based on the basic dimensional parameters of the inner wall of the cylinder and the planar fixed-point spraying properties of the spray gun. It constructs the relationship between the trajectory spacing and the cross-sectional angle, and a planar translational paint film thickness distribution model of the double-helix paint trajectory when the spray gun moves at a constant speed along the moving direction and the paint film accumulates directionally. The double-helix paint trajectory is the spraying trajectory obtained when the spraying travel mechanism moves at a constant speed along the axial direction of the cylinder, and two spray guns symmetrically mounted on the spraying travel mechanism rotate around the cylinder axis with their rotation centers coinciding with the cylinder axis. The cross-sectional angle is the angle between the linear motion trajectory obtained by shearing and unfolding the double-helix paint trajectory along the axial direction of the cylinder and the cross-section of the cylinder.

[0028] A cylindrical inner wall paint film thickness distribution model construction module is used to obtain a cylindrical inner wall paint film thickness distribution model based on the planar translation paint film thickness distribution model.

[0029] The cylindrical inner wall paint film thickness distribution model construction module is used to obtain a cylindrical inner wall paint film thickness distribution model that considers the paint film superposition phenomenon of adjacent trajectories by superimposing the cylindrical inner wall paint film thickness distribution model corresponding to adjacent trajectories under various different trajectory spacing values.

[0030] The paint thickness control module is used to adjust the spraying process parameters to control the paint thickness of the inner wall of the cylinder to be sprayed based on the paint film thickness distribution model of the inner wall of the cylinder and the relationship between the trajectory spacing and the cross-sectional angle. The spraying process parameters include the trajectory spacing, the spraying flow rate of the spray gun, the spraying distance, the spraying rotation speed and the moving speed of the spraying travel mechanism.

[0031] Optionally, the expression for the planar translational paint film thickness distribution model is:

[0032] Q0(x)=Q max (1-4x 2 / w 2 ) β-1

[0033] Where Q0(x) represents the paint thickness distribution across the cross-section of a uniformly sprayed linear section; Q max For maximum cumulative paint thickness, A is a constant; q is the spraying flow rate; w is the spraying width; β is an undetermined parameter in the double β distribution function; x is the horizontal distance between the projection point of the spraying area point O and point M on the spraying plane; the spraying area point O is the trajectory point on the plane where the linear motion trajectory obtained by shearing and unfolding the double helix spraying paint trajectory along the cylinder axis is located; the spray gun nozzle is point M.

[0034] Optionally, the expression for the paint film thickness distribution model on the inner wall of the cylinder is:

[0035]

[0036] Where h0 is the spraying distance; h1 is the distance from point M to plane K, plane K is the plane where point O′ is located, and point O′ is the projection of point O in the spraying area onto the arc surface of the inner wall of the cylinder; tanψ=x / h0; Let be the angle formed by the normal vectors of circular surface s3 and circular surface s4; circular surface s3 is a circular surface with center O′ and normal vector pointing to point M; circular surface s4 is a circular surface with center O′ and normal vector pointing to the center of the cylindrical cross-section passing through point O′.

[0037] Optionally, the expression for the coating thickness distribution model on the inner wall of the cylinder is:

[0038]

[0039] Where d is the distance between adjacent trajectories.

[0040] Optionally, the paint thickness control module specifically includes:

[0041] The thickness distribution function maximum and minimum value determination unit is used to determine the spraying distance of the spray gun and set different trajectory spacing values; the spraying distance and each trajectory spacing value are substituted into the cylinder inner wall paint film superposition thickness distribution model to obtain the maximum and minimum values ​​of the cylinder inner wall paint film superposition thickness distribution model function curve corresponding to each trajectory spacing value;

[0042] The trajectory spacing optimization unit is used to obtain the maximum and minimum values ​​corresponding to each trajectory spacing value; and select the trajectory spacing value whose maximum and minimum values ​​are less than the maximum allowable deviation of the actual paint film thickness.

[0043] The velocity relationship determination unit is used to determine the cross-sectional angle based on the selected trajectory spacing value and the relationship between the trajectory spacing and the cross-sectional angle; and to determine the velocity relationship between the moving speed and the rotating speed based on the cross-sectional angle.

[0044] The paint thickness control unit is used to adjust the moving speed of the spraying travel mechanism and the rotation speed of the spray gun according to the selected trajectory spacing value, the spraying distance, the spraying flow rate, and the speed relationship, so that the paint film thickness of the spraying trajectory on the inner wall of the cylinder to be sprayed satisfies the paint film superposition thickness distribution model of the inner wall of the cylinder; the spraying flow rate is determined according to the preset spraying time; the spraying flow rate and the moving speed of the spraying travel mechanism are positively correlated.

[0045] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0046] This invention provides a method and system for controlling paint thickness during double-helix superimposed spraying of the inner wall of a cylinder. The method includes constructing a planar translational paint film thickness distribution model and further constructing a superimposed paint film thickness distribution model for the inner wall of the cylinder. Based on the superimposed paint film thickness distribution model, a trajectory spacing value is determined to make the paint film thickness distribution more uniform. Then, the moving speed of the spraying walking mechanism and the rotation speed of the spray gun are adjusted according to the selected trajectory spacing value, spraying distance, spraying flow rate, and the speed relationship between the spraying moving mechanism and the spray gun. This makes the paint film thickness more uniform during the spraying process. The spraying time can be reduced by adjusting the spraying flow rate, and the double-helix spraying of the inner wall of the cylinder can be effectively completed in one go, improving the spraying efficiency. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a flowchart of a method for controlling paint thickness in a double-helix superimposed spraying method for the inner wall of a cylinder, provided in Embodiment 1 of the present invention;

[0049] Figure 2 This is a schematic diagram of the spraying device structure provided in Embodiment 1 of the present invention;

[0050] Figure 3 This is a schematic diagram of the spraying trajectory of the cylindrical spraying device provided in Embodiment 1 of the present invention;

[0051] Figure 4 This is a schematic diagram of horizontal spraying accumulation provided in Embodiment 1 of the present invention;

[0052] Figure 5 This is a schematic diagram of the projection of point O on the plane onto the concave arc surface (the arc surface of the inner wall of the cylinder) provided in Embodiment 1 of the present invention;

[0053] Figure 6 This is a schematic diagram of the relationship between circular surfaces with different included angles provided in Embodiment 1 of the present invention;

[0054] Figure 7 This is a schematic diagram of the geometric relationship between the planar oil film projected onto the concave arc surface according to Embodiment 1 of the present invention;

[0055] Figure 8 This is a schematic diagram of the superposition of oil film thicknesses on adjacent paint tracks provided in Embodiment 1 of the present invention;

[0056] Figure 9 This is a block diagram of a paint thickness control system for double-helix superimposed spraying on the inner wall of a cylinder, provided in Embodiment 2 of the present invention.

[0057] Figure label:

[0058] 1. Spraying travel mechanism; 2. Spray gun; 3. Inner wall of cylinder; 4. Spray gun rotation center; 5. Center of the arc of the section where the projection point O′ is located (i.e., point N). Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] The purpose of this invention is to provide a method and system for controlling paint thickness in a double-helix superimposed spraying process on the inner wall of a cylinder, which can ensure a more uniform distribution of sprayed paint thickness and improve spraying efficiency.

[0061] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0062] Example 1

[0063] like Figure 1 As shown, this embodiment provides a method for controlling paint thickness in a double-helix superimposed spraying process on the inner wall of a cylinder. The method is based on... Figure 2 The spraying device shown includes a spraying travel mechanism 1 and two spray guns 2 symmetrically arranged on both sides of the spraying travel mechanism 1. The spraying travel mechanism 1 moves at a constant speed along the axial direction of the cylinder inside the cylinder wall 3. The rotation centers 4 of the two spray guns 2 coincide with the cylinder axis. The connecting rods between the two spray guns 2 and the rotation centers 4 are on the same straight line.

[0064] The spraying walking mechanism 1 moves along the cylinder axis at a speed of v. Two spray guns 2 are symmetrically installed. The distance between the spray guns 2 and the inner wall 3 of the cylinder is constant, i.e., the spraying distance is h0. The rotation center 4 of the two guns coincides with the cylinder axis. The angular velocity of the spray guns 2 is ω. When the two velocities are combined, the spraying path is in the form of a double helix.

[0065] The method includes:

[0066] S1: Obtain the basic dimensional parameters of the inner wall of the cylinder and the planar fixed-point spraying properties of the spray gun.

[0067] The basic dimensional parameters of the inner wall of the cylinder include the inner diameter R and length L. The planar fixed-point spraying attributes of the spray gun include the spray flow rate q, the spray distance h0, and the spray width.

[0068] S2: Based on the basic dimensional parameters of the inner wall of the cylinder and the planar fixed-point spraying properties of the spray gun, analyze the double-helix spraying paint trajectory of the spraying device, construct the relationship between the trajectory spacing and the cross-sectional angle, and construct the planar translational paint film thickness distribution model of the double-helix spraying paint trajectory when the spray gun moves at a constant speed along the moving direction and the paint film accumulates in a directional manner; the double-helix spraying paint trajectory is the spraying trajectory obtained by the spray gun spraying paint when the spraying travel mechanism moves at a constant speed along the cylinder axis on the inner wall of the cylinder, and the two spray guns symmetrically arranged on the spraying travel mechanism rotate around the cylinder axis and the rotation center of the two spray guns coincides with the cylinder axis; the cross-sectional angle is the angle between the straight motion trajectory obtained by shearing and unfolding the double-helix spraying paint trajectory along the cylinder axis and the cylinder cross-section.

[0069] Specifically, the spraying travel mechanism 1 moves at a constant speed along the axial direction of the cylinder, and the two spray guns on the spraying travel mechanism 1 rotate around the axis, resulting in a double helix pattern for the paint spraying. Figure 3 As shown, the double helix on the inner wall of the cylinder is sheared and unfolded axially. The spraying trajectory moves in a straight line at a uniform speed, with an angle α between the trajectory and the cylinder cross-section. The distance between adjacent paint trajectories is d. The rotation period of the two spray guns is T, i.e., T = 2π / ω.

[0070] like Figure 4 As shown, when the spray flow rate q and spray distance h0 are fixed, the cumulative thickness of the paint film sprayed by the spray gun 2 on the plane is determined by a double-β model, that is, the cumulative thickness of the paint film sprayed at fixed points on the plane follows a double-β distribution function. This is based on the theoretical formula of the double-β distribution function. A double-β distribution model for the cumulative paint film thickness during fixed-point spraying with a spray gun is constructed, where k is a constant, a, b, β1, and β2 are constants, and x and y are variables. The spray gun moves at a constant speed along the direction of movement, and the paint film accumulates directionally, thus constructing a planar translational paint film thickness distribution model: Q0(x) = Q max (1-4x 2 / w 2 ) β-1 For a single uniform linear spraying trajectory, a rectangular coordinate system is established based on its cross-section, where Q0(x) represents the paint film thickness at the corresponding x-position.

[0071] The planar translational paint film thickness distribution model can be obtained by integrating the cumulative double β model of paint film thickness at fixed points along the direction of movement or by fitting points to the cross section of the paint film when spraying at a constant speed in a straight line on the plane of the spray gun.

[0072] Among them, Q maxLet w be the maximum cumulative paint thickness, w be the spray width, and β be an undetermined parameter in the double β distribution function, which is a constant that can be calculated during integration or fitting. Let the spray gun nozzle be point M, and x be the horizontal distance from the spray area point O to the projection point of the spray gun M on the spray plane.

[0073] according to It can be seen that, keeping the spraying distance h0 and other conditions constant, the cumulative paint thickness can be changed by adjusting the spraying flow rate q; with the spraying flow rate q and other related conditions remaining constant, the spraying width w is positively correlated with the spraying distance h0. A is a constant.

[0074] S3: Obtain the coating thickness distribution model of the inner wall of the cylinder based on the planar translation coating thickness distribution model.

[0075] With spray flow rate q and other relevant conditions remaining constant, the spray width w is directly proportional to the spray distance h0. For example... Figure 5 As shown, during spraying, point O on plane J (the plane containing the linear motion trajectory obtained by shearing and unfolding the double-helix spray paint path along the cylinder axis) is projected onto the arc surface of the inner wall of the cylinder as point O′. Point O′ lies on plane K, and planes J and K are parallel. The distance from point M to plane K is h1 (i.e., the perpendicular distance from O′ to the spray gun M is h1). The smallest circular surface of point O on plane J is s1, the paint thickness on s1 is Q1, and the projection of s1 onto plane K is s2. s3 is a small circular surface passing through point O′ with its normal vector pointing to point M. The paint thickness on s3 is Q3, where Q3 = Q2 / cosψ and tanψ = x / h0. ψ is the angle between OM and the vertical direction of the spray gun. Let O′N be the angle between O′N and O′M, and N be the center of the circle passing through the O′ section.

[0076] like Figure 6 As shown, s4 is a small circular surface passing through point O′ with its normal vector pointing to the center of the circle, i.e. Let Q4 be the angle formed by the normal vectors of circular surface s3 and s4. That is, the paint thickness Q4 on circular surface s4 is the final projected paint thickness Q. s ,Right now:

[0077] like Figure 7 As shown, the projection of the paint film thickness from a point O on the planar spraying area onto the inner wall 3 of the cylinder satisfies the following geometric relationship. That is, the paint film thickness distribution model on the inner wall of the cylinder is:

[0078] According to geometric relationships, This can be derived using the Law of Cosines:

[0079]

[0080] l NO'=R;

[0081]

[0082]

[0083] h1 = h0 - (R - Rcosθ);

[0084] h1 tanψsinα=Rsinθ.

[0085] θ is the central angle formed by ON and the vertical direction of the center N.

[0086] S4: Under various trajectory spacing values, the cylinder inner wall paint film thickness distribution model is obtained by superimposing the paint film thickness distribution models corresponding to adjacent trajectories. This model considers the paint film superposition phenomenon of adjacent trajectories.

[0087] like Figure 8 As shown, to control the change in paint film thickness, the spacing d between adjacent paint tracks needs to be adjusted, where d ≥ w / 2. Therefore, there is an oil film superposition phenomenon between adjacent paint tracks, i.e., the paint film superposition thickness distribution model on the inner wall of the cylinder is: To minimize the variation in paint thickness within a certain spacing while still meeting usage requirements, i.e., |f max -f min |≤ε. According to |f max -f min |≤ε, where ε is the maximum allowable deviation. Adjust the spacing d between adjacent paint tracks to make the paint thickness distribution in the area between adjacent paint tracks more uniform.

[0088] S5: Adjust the spraying process parameters to control the paint thickness on the inner wall of the cylinder to be sprayed based on the coating thickness distribution model of the inner wall of the cylinder and the relationship between the trajectory spacing and the cross-sectional angle; the spraying process parameters include the trajectory spacing, the spraying flow rate of the spray gun, the spraying distance, the spraying rotation speed and the moving speed of the spraying travel mechanism.

[0089] The moving speed v of the spraying mechanism and the rotational speed ω of the spray gun are simultaneously affected by the spray flow rate q, the spray distance h0, and the trajectory spacing d. During the spraying process, a suitable spray flow rate q and spray distance h0 are selected and kept constant. An appropriate spacing d between adjacent paint trajectories is selected based on the paint thickness deviation. Simultaneously, the relationship between the moving speed of the spraying mechanism and the rotational speed of the spray gun can be calculated based on the spacing d between adjacent paint trajectories. For example: Where v is the moving speed of the spraying travel mechanism, and ω is the rotational speed of the spray gun.

[0090] Specifically, step S5 includes:

[0091] (1) Determine the spraying distance of the spray gun and set different track spacing values; substitute the spraying distance and each track spacing value into the film thickness superposition distribution model of the inner wall of the cylinder to obtain the maximum and minimum values of the function curve of the film thickness superposition distribution model of the inner wall of the cylinder corresponding to each track spacing value.

[0092] (2) Obtain the maximum-minimum deviation corresponding to each track spacing value according to the maximum value and the minimum value; select the track spacing value corresponding to the maximum-minimum deviation less than the maximum allowable deviation of the actual film thickness.

[0093] (3) Determine the cross-sectional angle according to the selected track spacing value and the relational expression between the track spacing and the cross-sectional angle; determine the speed relationship between the moving speed and the rotating speed according to the cross-sectional angle.

[0094] (4) Adjust the moving speed of the spraying walking mechanism and the rotating speed of the spray gun according to the selected track spacing value, the spraying distance, the spraying flow rate, and the speed relationship, so that the film thickness of the spraying track on the inner wall of the to-be-sprayed cylinder meets the film thickness superposition distribution model of the inner wall of the cylinder; the spraying flow rate is determined according to the preset spraying time; the spraying flow rate and the moving speed of the spraying walking mechanism are positively correlated. The spray gun flow rate and the spraying distance can be adjusted according to the pipe diameter.

[0095] In the spraying working condition, the inner diameter of the cylinder is R and the length is L. The spraying distance h0 < R, and the spraying time T = L / v. Thus, the spraying flow rate q, the spraying distance h0, and the track spacing d can be adjusted while maintaining the film thickness, and the moving speed v of the spraying walking mechanism and the rotating speed ω of the spray gun can be increased, thereby improving the spraying efficiency.

[0096] In this embodiment, according to the spraying conditions of the spraying walking mechanism, a fixed-point plane spraying film thickness accumulation model is constructed and further transformed into a uniform motion plane translation spraying film thickness distribution model; through the basic parameters in the cylinder, the plane translation film model is projected onto the inner wall of the cylinder to establish a film thickness accumulation model of the inner wall of the cylinder; the adjacent paint track spacing is adjusted to obtain a film thickness superposition distribution model of the inner wall of the cylinder, so that the film thickness distribution deviation in the overlapping area is minimized and the spraying effect is more uniform; the process parameters required for double-spiral spraying in the cylinder are readjusted while ensuring the film thickness uniformity and the spraying efficiency. The present invention adopts a double-spiral spraying method to achieve a one-time complete spraying of the inner wall of the cylinder while ensuring the spraying thickness, thereby improving the spraying efficiency.

[0097] Embodiment 2

[0098] As Figure 9 shown, this embodiment provides a paint thickness control system for double-spiral superposition spraying on the inner wall of a cylinder, including:

[0099] The basic data acquisition module 100 is used to acquire the basic dimensional parameters of the inner wall of the cylinder and the planar fixed-point spraying attributes of the spray gun.

[0100] The planar translational paint film thickness distribution model construction module 200 is used to analyze the double-helix paint trajectory of the spraying device based on the basic dimensional parameters of the inner wall of the cylinder and the planar fixed-point spraying attributes of the spray gun. It constructs the relationship between the trajectory spacing and the cross-sectional angle, and a planar translational paint film thickness distribution model of the double-helix paint trajectory when the spray gun moves at a constant speed along the moving direction and the paint film accumulates in a directional manner. The double-helix paint trajectory is the spraying trajectory obtained by the spray guns spraying paint when the spraying travel mechanism moves at a constant speed along the cylinder axis on the inner wall of the cylinder, and two spray guns symmetrically mounted on the spraying travel mechanism rotate around the cylinder axis with their rotation centers coinciding with the cylinder axis. The cross-sectional angle is the angle between the linear motion trajectory obtained by shearing and unfolding the double-helix paint trajectory along the cylinder axis and the cross-section of the cylinder.

[0101] The expression for the planar translational paint film thickness distribution model is as follows:

[0102] Q0(x)=Q max (1-4x 2 / w 2 ) β-1

[0103] Where Q0(x) represents the paint thickness distribution across the cross-section of a uniformly sprayed linear section; Q max For maximum cumulative paint thickness, A is a constant; q is the spraying flow rate; w is the spraying width; β is an undetermined parameter in the double β distribution function; x is the horizontal distance between the projection point of the spraying area point O and point M on the spraying plane; the spraying area point O is the trajectory point on the plane where the linear motion trajectory obtained by shearing and unfolding the double helix spraying paint trajectory along the cylinder axis is located; the spray gun nozzle is point M.

[0104] The cylindrical inner wall paint film thickness distribution model construction module 300 is used to obtain the cylindrical inner wall paint film thickness distribution model based on the planar translation paint film thickness distribution model.

[0105] The expression for the paint film thickness distribution model on the inner wall of the cylinder is as follows:

[0106]

[0107] Where h0 is the spraying distance; h1 is the distance from point M to plane K, plane K is the plane where point O′ is located, and point O′ is the projection of point O in the spraying area onto the arc surface of the inner wall of the cylinder; tanψ=x / h0; Let be the angle formed by the normal vectors of circular surface s3 and circular surface s4; circular surface s3 is a circular surface with center O′ and normal vector pointing to point M; circular surface s4 is a circular surface with center O′ and normal vector pointing to the center of the cylindrical cross-section passing through point O′.

[0108] The cylindrical inner wall paint film thickness distribution model construction module 400 is used to obtain a cylindrical inner wall paint film thickness distribution model that considers the paint film superposition phenomenon of adjacent trajectories by superimposing the cylindrical inner wall paint film thickness distribution model corresponding to adjacent trajectories under various different trajectory spacing values.

[0109] The expression for the thickness distribution model of the coating film superposition on the inner wall of the cylinder is as follows:

[0110]

[0111] Where d is the distance between adjacent trajectories.

[0112] The paint thickness control module 500 is used to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the paint film superposition thickness distribution model of the inner wall of the cylinder and the relationship between the trajectory spacing and the cross-sectional angle; the spraying process parameters include the trajectory spacing, the spraying flow rate of the spray gun, the spraying distance, the spraying rotation speed and the moving speed of the spraying travel mechanism.

[0113] Specifically, the paint thickness control module 500 includes:

[0114] The thickness distribution function extremum determination unit is used to determine the spraying distance of the spray gun and set different trajectory spacing values; the spraying distance and each trajectory spacing value are substituted into the cylinder inner wall paint film superposition thickness distribution model to obtain the maximum and minimum values ​​of the cylinder inner wall paint film superposition thickness distribution model function curve corresponding to each trajectory spacing value.

[0115] The trajectory spacing optimization unit is used to obtain the maximum and minimum values ​​corresponding to each trajectory spacing value; and select the trajectory spacing value corresponding to the maximum deviation of the maximum deviation of the actual paint film thickness.

[0116] The velocity relationship determination unit is used to determine the cross-sectional angle based on the selected trajectory spacing value and the relationship between the trajectory spacing and the cross-sectional angle; and to determine the velocity relationship between the moving speed and the rotating speed based on the cross-sectional angle.

[0117] The paint thickness control unit is used to adjust the moving speed of the spraying travel mechanism and the rotation speed of the spray gun according to the selected trajectory spacing value, the spraying distance, the spraying flow rate, and the speed relationship, so that the paint film thickness of the spraying trajectory on the inner wall of the cylinder to be sprayed satisfies the paint film superposition thickness distribution model of the inner wall of the cylinder; the spraying flow rate is determined according to the preset spraying time; the spraying flow rate and the moving speed of the spraying travel mechanism are positively correlated.

[0118] Each embodiment focuses on describing the differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for helping to understand the methods and core ideas of the present invention; furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for controlling the paint thickness of a double helix over spray on the inside wall of a cylinder, characterized by, The method comprises the following steps: acquiring the basic size parameters of the inner wall of the cylinder and the planar fixed-point spraying attributes of the spray gun; analyzing the double-helix spraying paint track of the spraying device according to the basic size parameters of the inner wall of the cylinder and the planar fixed-point spraying attributes of the spray gun, constructing a relationship between the track spacing and the cross-section angle, and a planar translation paint film thickness distribution model of the double-helix spraying paint track when the paint film is oriented and accumulated at a constant speed along the moving direction of the spray gun; the double-helix spraying paint track is obtained by spraying paint with the spray gun under the condition that the spraying walking mechanism moves at a constant speed along the axial direction of the cylinder, two spray guns symmetrically arranged on the spraying walking mechanism rotate around the cylinder axis, and the rotation centers of the two spray guns coincide with the cylinder axis; the cross-section angle is the angle between the straight-line motion track obtained by cutting and expanding the double-helix spraying paint track along the axial direction of the cylinder and the cross section of the cylinder; obtaining the paint film thickness distribution model of the inner wall of the cylinder according to the planar translation paint film thickness distribution model; under the condition of multiple different track spacing values, superimposing the paint film thickness distribution models of the inner wall of the cylinder corresponding to adjacent tracks to obtain a paint film superposition thickness distribution model of the inner wall of the cylinder considering the paint film superposition phenomenon of adjacent tracks; adjusting the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the paint film superposition thickness distribution model of the inner wall of the cylinder and the relationship between the track spacing and the cross-section angle; the spraying process parameters include the track spacing, the spraying flow, the spraying distance, the spraying rotation speed of the spray gun, and the moving speed of the spraying walking mechanism; wherein, adjusting the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the paint film superposition thickness distribution model of the inner wall of the cylinder and the relationship between the track spacing and the cross-section angle, specifically comprising: determining the spraying distance of the spray gun and setting different track spacing values; the spraying distance and each track spacing value are brought into the paint film superposition thickness distribution model of the inner wall of the cylinder to obtain the maximum value and the minimum value of the paint film superposition thickness distribution model function curve corresponding to each track spacing value; obtaining the maximum and minimum values corresponding to each track spacing value according to the maximum and minimum values; selecting the track spacing value corresponding to the maximum and minimum values smaller than the actual maximum allowed deviation of the paint film thickness; determining the cross-section angle according to the selected track spacing value and the relationship between the track spacing and the cross-section angle; determining the speed relationship between the moving speed and the rotation speed according to the cross-section angle; adjusting the moving speed of the spraying walking mechanism and the rotation speed of the spray gun according to the selected track spacing value, the spraying distance, the spraying flow, and the speed relationship, so that the paint film thickness of the spraying track of the inner wall of the cylinder to be sprayed satisfies the paint film superposition thickness distribution model of the inner wall of the cylinder; the spraying flow is determined according to the preset spraying time; the spraying flow and the moving speed of the spraying walking mechanism are positively correlated; wherein, the expression of the paint film superposition thickness distribution model of the inner wall of the cylinder is: in, d The distance between adjacent trajectories; This is a model of the paint film thickness distribution on the inner wall of a cylinder. ; This indicates the paint thickness distribution across a cross-section where the spray gun is used for uniform linear spraying. ; For maximum cumulative paint thickness, ; h 0 represents the spraying distance; Let M be the distance from point M to plane K, and let plane K be... The plane containing the point, the spraying area point O The projection onto the arc surface of the inner wall of the cylinder is point; ; Circular surface normal vector and circle The angle formed by the normal vectors; a circular surface Therefore The point is the center of the circle and the normal vector points to... M The circle of a point ； round surface For The point is the center of the circle and the normal vector points through it. The center of the cylindrical cross-section at the point; A is a constant; q is the spray flow rate; For spraying width; For double Undetermined parameters in the distribution function; The horizontal distance from point O to point M on the spraying plane is the projection of the spraying area point O onto the spraying plane; point O is the trajectory point on the plane where the linear motion trajectory of the double-helix spraying paint trajectory is obtained by shearing and unfolding along the axial direction of the cylinder; the spray gun nozzle is... M point; The angle between OM and the vertical direction of the spray gun.

2. A paint thickness control system for double helical over-the-cylinder- wall spray, characterized by The method comprises the following steps: acquiring the basic size parameters of the inner wall of the cylinder and the planar fixed-point spraying attributes of the spray gun; The plane translation paint film thickness distribution model construction module is configured to analyze a double helix paint spraying track of the spraying device according to the basic size parameters of the inner wall of the cylinder and the plane fixed-point spraying attribute of the spray gun, and to construct a relationship between a track spacing and a cross-section angle and a plane translation paint film thickness distribution model of the double helix paint spraying track when the spray gun moves at a constant speed along a moving direction and the paint film is accumulated in a directional manner. The double helix paint spraying track is obtained by spraying paint by the spray gun under the condition that the spraying walking mechanism moves at a constant speed along the axial direction of the cylinder, the two spray guns are symmetrically arranged on the spraying walking mechanism and rotate around the cylinder axis, and the rotation center of the two spray guns coincides with the cylinder axis. The cross-section angle is an angle between a straight line motion track obtained by cutting and developing the double helix paint spraying track along the axial direction of the cylinder and a cross section of the cylinder. The cylinder inner wall paint film thickness distribution model construction module is configured to obtain a cylinder inner wall paint film thickness distribution model according to the plane translation paint film thickness distribution model. The cylinder inner wall paint film superposition thickness distribution model construction module is configured to obtain a cylinder inner wall paint film superposition thickness distribution model considering the paint film superposition phenomenon of adjacent tracks by superimposing the cylinder inner wall paint film thickness distribution models corresponding to the adjacent tracks under the condition of multiple different track spacing values. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The spraying process parameters include the track spacing, the spraying flow, the spraying distance, the spraying rotation speed of the spray gun, and the moving speed of the spraying walking mechanism. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder to be sprayed by adjusting the spraying process parameters according to the cylinder inner wall paint film superposition thickness distribution model and the relationship between the track spacing and the cross-section angle. The paint thickness control module is configured to control the paint thickness of the inner wall of the cylinder wherein, d is the adjacent track spacing; is the inner wall paint film thickness distribution model of the cylinder, ; represents the paint thickness distribution of the cross section of the straight-line spraying of the spray gun at a constant speed, ; is the maximum paint cumulative thickness, ; h 0 is the spraying distance; is the distance from point M to plane K, and plane K is the plane on which point M is located, and the projection of the spraying area point O onto the circular arc surface of the inner wall of the cylinder is point; ; is the angle between the normal vector of the circular surface and the normal vector of the circular surface ; the circular surface is a circular surface with point as the center and the normal vector pointing to M point; ； circular surface is a circular surface with point as the center and the normal vector pointing to the center of the cylinder section passing through point; A is a constant; q is the spraying flow rate; is the spraying width; is the undetermined parameter in the double distribution function; is the horizontal distance from the spraying area point O to the projection point of point M on the spraying plane; the spraying area point O is a track point on the plane of the straight-line motion track obtained by shearing and developing the double helix paint spraying track along the axis of the cylinder; the spray gun nozzle is M point; is the angle between OM and the vertical direction of the spray gun.

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