Variable-flow continuous and uniform spraying control method for inner wall of circular-truncated-cone-shaped pipeline

Abstract

The invention discloses a variable-flow continuous and uniform spraying control method for the inner wall of a circular-truncated-cone-shaped pipeline. The method comprises the steps that parameters of the spatial shape of a spraying curved surface of the inner wall of a wind power tower drum are obtained; the spraying path is a spiral curve; on the basis of the spraying path, spraying process parameters of the spraying robot are calculated according to preset spraying production requirement data; and the spraying robot is controlled to spray the inner wall of the circular-truncated-cone-shaped pipeline according to the spraying process parameters and the spraying path. According to the invention, the spraying flow is increased in order to ensure the consistent spraying thickness under the condition that the inner diameter of the pipeline is increased, so that the spraying uniformity and the spraying efficiency can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of spraying, and particularly relates to a control method for continuously and uniformly spraying with variable flow on the inner wall of a frustum-shaped pipe. Background Art

[0002] Spraying is one of the important processes in the field of machine manufacturing. At present, manual spraying is mainly used in the field of spraying the inner wall of wind power tower barrels, and there is no automated spraying process. Manual spraying cannot accurately control the thickness of the paint film. It is necessary to wait for the paint film to dry and then use a steel film meter to measure the thickness of the paint film. If the paint film is too thick or too thin, it is necessary to adjust the spraying speed or the proportion of the diluent to control the corresponding thickness, resulting in low spraying efficiency; a large number of metal nail components are welded on the inner wall of the tower barrel before spraying operation, which further hinders the operation of workers; when the workers walk and spray on the inner wall of the tower barrel, it is easy to damage the already sprayed paint film; manual spraying cannot ensure that the spraying quality meets the production requirements. The air flow inside the tower barrel is poor, and when working manually, it is extremely easy to inhale toxic and harmful components such as formaldehyde, benzene, and VOC contained in the paint, which is not conducive to the health of the workers. The patent with the publication number CN114798255A discloses a spraying method for the inner wall of a pipe with variable diameter. This patent ensures uniform spraying by controlling the moving speed of the spraying robot and the linear speed of the nozzle, etc. However, during the spraying process, as the diameter of the pipe continuously increases, the surface area to be sprayed also increases accordingly. If the nozzle flow rate remains unchanged, the thickness of the sprayed surface cannot meet the actual requirements, and there is still the technical problem of inconsistent spraying thickness when the pipe diameter changes. Summary of the Invention

[0003] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides a control method for continuously and uniformly spraying with variable flow on the inner wall of a frustum-shaped pipe.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is: a control method for continuously and uniformly spraying with variable flow on the inner wall of a frustum-shaped pipe, which uses a spraying robot for spraying. The spraying robot includes a base, a nozzle support arm, a nozzle link arm, a nozzle rotating arm, and a spray gun. The base moves in a uniform linear motion on the inner wall of the frustum-shaped pipe; the nozzle support arm is connected to the base and moves up and down in a direction perpendicular to the base; the nozzle link arm is connected to the nozzle support arm, and the nozzle link arm rotates around one end of the nozzle support arm; the nozzle rotating arm is connected to the nozzle link arm, and the nozzle rotating arm makes a circular motion with the nozzle link arm as the rotation center; the spray gun is connected to the nozzle rotating arm, and the spray gun rotates around one end of the rotating arm; and the spray gun is telescopic. Its characteristics include the following steps:

[0005] Obtain the parameters of the spatial shape of the spraying curved surface on the inner wall of the frustum-shaped pipe;

[0006] Obtain the spraying production requirements according to the actual engineering needs;

[0007] Calculate the spraying process parameters of the spraying robot according to the preset spraying parameters; Calculate the spraying process parameters of the spraying robot according to the preset spraying parameters; The spraying process parameters are the base speed of the spraying robot, the telescopic speed of the support arm, the rotational angular velocity of the rotating arm, the telescopic speed of the nozzle, and the flow rate change function of the spraying robot; The formula for the flow rate change function of the spraying robot is:

[0008] where t is the spraying time; H is the spraying thickness; ω is the rotational angular velocity of the rotating arm; r1 is the radius of the small-area end face of the two end faces of the frustum-shaped pipe; L is the total length of the pipe; φ is the angle between the pipe bus and the axis; T is the total spraying time; is the length of the rotating arm; h is the distance between the nozzle and the sprayed surface; θ is the divergence angle of the nozzle spraying; d is the spraying width; Control the spraying robot to spray the inner wall of the frustum-shaped pipe according to the spraying process parameters and the spraying path.

[0009] Control the spraying robot to spray the inner wall of the frustum-shaped pipe according to the spraying process parameters and the spraying path.

[0010] Furthermore, the parameters of the sprayed curved surface space shape include the total length of the pipe, the radius of the small-area end face of the two end faces of the frustum-shaped pipe, and the inclination angle between the pipe axis and the bus.

[0011] Furthermore, the spraying path is a spiral curve;

[0012] Furthermore, the base speed of the spraying robot is:

[0013] ;

[0014] where L is the total length of the pipe; T is the total spraying time; φ is the angle between the pipe bus and the axis; V 轴 is the axial component speed when the spraying robot walks along the wall surface.

[0015] Furthermore, the telescopic speed of the support arm of the spraying robot is:

[0016] .

[0017] Furthermore, the rotational angular velocity of the rotating arm of the spraying robot is:

[0018] ; where n is the number of nozzles.

[0019] Furthermore, the telescopic speed of the nozzle of the spraying robot is:

[0020] 。

[0021] Advantages of the present invention:

[0022] Based on the area sprayed by the nozzle per unit time and the required thickness of the sprayed surface, the present invention establishes a flow rate change function, and controls the spraying robot to spray continuously and evenly according to the flow rate change function and other process parameters, greatly improving the spraying uniformity and spraying efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flowchart of the present invention.

[0024] Figure 2 is a spraying motion diagram of the spraying robot for the inner wall of the frustum-shaped pipe in the present invention.

[0025] Figure 3 is a projection relationship diagram of the same generatrix covered by two adjacent nozzles A and B within one rotation period in the present invention.

[0026] Figure 4 is a schematic diagram of the width of the nozzle and the actual width of the inner wall of the pipe to be sprayed in the present invention.

[0027] Figure 5 is a legend of each parameter in the formula derivation process of the present invention.

[0028] Figure 6 is a spraying trajectory diagram with two nozzles as an example in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0030] Refer to Figure 1 , Figure 1 which is a flowchart of the present invention. In the present invention, a spraying robot is used to realize the spraying of the inner wall of the frustum-shaped pipe. The movement of the spraying robot for the inner wall of the frustum-shaped pipe is as Figure 2As shown in the figure. The base 2 of the spraying robot moves on one side of the inner wall 1 by using tires, forming a moving pair to ensure the movement of the spraying robot; the support arm 3 can move up and down along the direction perpendicular to the bottom line, forming a moving pair to ensure that the connecting arm 4 always coincides with the pipeline axis; the connecting arm 4 is connected to the support arm 3 with a rotating pair and can rotate within a certain angle to ensure that when working in pipelines with different inner wall inclination angles (the angle between the pipeline axis and the generatrix), the connecting arm 4 coincides with the pipeline axis at the initial spraying position; the rotating arm 5 is connected to the connecting arm 4 with a rotating pair, enabling the rotating arm 5 to make a circumferential movement with the connecting arm 4 as the rotation center; the nozzle 6 is connected to the rotating arm 5 with a rotating pair, enabling the nozzle 6 to rotate a certain angle to ensure that the spraying direction of the nozzle 6 is always perpendicular to the inner wall; a moving pair is added to the nozzle 6 to allow the nozzle 6 to contract along the existing direction; the spraying robot with the above movable joints can maintain the position of the nozzle 6 within the working range of the spraying robot, spray the curved surface as required, and achieve continuous and uniform spraying of the pipeline inner wall.

[0031] A method for continuously and uniformly spraying the inner wall of a variable-diameter pipeline provided by the present invention includes the following steps:

[0032] Step 100: Obtain the parameters of the spatial shape of the spraying curved surface on the inner wall of the frustum-shaped pipeline; the parameters include the total length L of the pipeline, the radius r1 of the small-area end face at both ends of the frustum-shaped pipeline, and the angle φ between the generatrix and the axis.

[0033] Step 200: Determine the spraying production requirements according to the actual engineering needs, including determining the total spraying time T; the spraying thickness H; the number of nozzles n; the width d of the nozzle; the divergence angle θ of the nozzle during spraying; the distance h between the nozzle and the sprayed surface; the length of the rotating arm .

[0034] Step 300: Based on the spraying production requirements, calculate the spraying feed process parameters of the spraying robot, including: the base speed of the spraying robot, the telescopic speed of the support arm, the rotational angular velocity of the rotating arm, the telescopic speed of the nozzle, and the flow rate change function of the spraying robot. Specifically, establish formulas according to the corresponding projection relationships to obtain the corresponding motion parameters as follows: Figures 3 - 5 The corresponding projection relationships are used to establish formulas to obtain the corresponding motion parameters as follows:

[0035] To ensure uniform spraying, the rotation center of the rotating arm needs to always coincide with the pipeline axis, and the relative position between the nozzle and the inner wall also needs to be kept unchanged. Therefore, before the equipment runs, it is necessary to adjust the angle between the connecting arm and the support arm to , adjust the support arm to make the connecting arm coincide with the pipeline axis; adjust the angle between the nozzle and the rotating arm to .

[0036] Since the robot moves uniformly along one side of the pipeline, to ensure that the connecting arm always coincides with the pipeline axis and to meetFigure 3 For the projection relationship shown, it is necessary to constrain the motion parameters.

[0037] According to the formula and the velocity of the spraying robot moving in a uniform straight line along the generatrix on one side of the inner wall of the pipe can be obtained, where L is the total length of the pipe; T is the total spraying time; φ is the angle between the generatrix of the pipe and the axis; V 轴 is the axial component velocity when the spraying robot walks along the wall; V is the velocity when the spraying robot walks along the wall, that is, the base velocity of the spraying machine.

[0038] According to the formula the nozzle telescopic velocity can be obtained; where V 喷 is the nozzle telescopic velocity, L is the total length of the pipe; φ is the angle between the generatrix of the pipe and the axis, and T is the total spraying time.

[0039] According to the formula the telescopic velocity of the support arm can be obtained; where V 支 is the telescopic velocity of the support arm, and the direction is parallel to the support arm; φ is the angle between the generatrix of the pipe and the axis; T is the total spraying time.

[0040] As Figure 4 shown, after the spraying material is atomized by the nozzle, the actual width covered on the inner wall is greater than the nozzle width, so it is necessary to first obtain the actual spraying width of the nozzle on the wall. The preset nozzle width is d;

[0041] According to the formula ; where d0 is the actual spraying width on the wall; h is the distance between the nozzle and the wall; θ is the divergence angle of the nozzle spraying.

[0042] The nozzle shows periodic motion during spraying; therefore, on the premise of ensuring that the rotation center of the nozzle and the relative position between the nozzle and the wall remain unchanged, uniform spraying in one cycle ensures uniform spraying throughout the spraying process.

[0043] According to the formula the rotation period of the nozzle can be obtained, where T 旋 is the time required for the nozzle to rotate 2π; ω is the rotation angular velocity of the rotating arm.

[0044] To enhance the universality of this control, the number of nozzles is preset to n; and they are evenly distributed; that is, the angle between adjacent two nozzles is .

[0045] According to the formula the time difference when adjacent two nozzles spray on the same generatrix during a cycle of spraying process can be obtained, where T 差is the time difference between two adjacent nozzles passing through the same generatrix.

[0046] According to the formula derived above, it is known that .

[0047] According to the formula the time difference between two adjacent nozzles passing through the same generatrix is obtained, which is the distance moved by the axial direction of the spraying robot.

[0048] According to the formula the moving projection distance of the spraying robot in the wall direction is obtained.

[0049] Combining the above-derived formula and Figure 3 the nozzle projection relationship, it can be obtained that on the premise of ensuring that the rotation center of the nozzle always coincides with the axis and the spraying distance between the nozzle and the wall does not change, to meet the condition of uniform spraying, it is necessary to satisfy , then the design requirements are met.

[0050] According to the above formula, the parameter conditions for continuous spraying on the inner wall of the frustum-shaped pipe are obtained as follows: ;

[0051] where L is the total length of the pipe; n is the number of nozzles; ω is the angular velocity of the rotating arm; φ is the angle between the generatrix of the pipe and the axis; h is the distance between the nozzle and the wall; θ is the divergence angle of the nozzle spraying; d is the width of the nozzle.

[0052] Simplifying the formula, the angular velocity formula of the rotating arm can be obtained: , where n is the number of nozzles.

[0053] According to the parameters of the spraying curved surface space shape on the inner wall of the frustum-shaped pipe and the actual engineering requirements, the basic operating parameters of the spraying robot are obtained.

[0054] As known from the above, the distance between the nozzle and the wall has not changed, and the spraying width of the nozzle on the wall has also remained consistent. However, as the pipe diameter increases, with the angular velocity ω remaining constant, from the formula it can be seen that the linear velocity also changes with the pipe diameter. r represents the pipe diameter, which will cause the spraying thickness to decrease as the pipe diameter increases. Therefore, it is necessary to increase the nozzle flow rate according to the requirements to ensure the consistency of the spraying thickness.

[0055] Since the pipe diameters at different positions on the axis in the frustum-shaped pipe are different, the function represents the pipe diameter size at any position; where is the distance between a certain point on the axis and the end face of the small area end among the two end faces of the frustum-shaped pipe.

[0056] The function That is, it represents the rotation radius of the nozzle at any position; among them is the length of the rotating arm; h is the distance between the nozzle and the inner wall of the pipeline.

[0057] When the rotating arm rotates, the inner wall arc length function covered per unit time is: .

[0058] The area function covered per unit time is: .

[0059] The volume sprayed per unit time is the flow rate q, and this volume is equal to the area S(x) covered per unit time multiplied by the thickness H; that is, the nozzle flow rate change function is derived as: ; among them, the independent variable x of the function is represented by a certain time node t in the spraying process, that is ; Therefore, the flow rate change function is transformed into: .

[0060] The confirmation process of the spraying process parameters in the embodiment of the present invention is as follows:

[0061] First, determine the specific parameters of the spraying surface: the total length of the pipeline L = 30000mm, the angle φ between the generatrix and the axis = 30°, and the radius of the smaller end face is r1 = 5000mm.

[0062] Determine the spraying production requirements: the total spraying time T = 300s; the spraying thickness H = 1mm; the number of nozzles n = 2; the nozzle width d = 20m; the divergence angle θ of the nozzle during spraying = 30°; the distance h between the nozzle and the sprayed surface = 1000mm; the length of the rotating arm = 1000mm.

[0063] Then it can be calculated:

[0064] The base speed of the spraying robot is: .

[0065] The telescopic speed of the support arm of the spraying robot is: .

[0066] The rotation speed of the rotating arm of the spraying robot is: .

[0067] The telescopic speed of the nozzle of the spraying robot is: .

[0068] The flow rate change function formula of the spraying robot is as follows: .

[0069] Step 400: Control the spraying robot to spray the inner wall of the frustum-shaped pipe according to the spraying process parameters and the spraying path.

[0070] To ensure the complete spraying of the inner wall of the pipe and avoid the phenomenon that the material volumes at the center and the boundary of the area are different during the fan-shaped atomization spraying of the nozzle and avoid missed spraying, it is necessary to constrain the spraying projection relationship between two adjacent nozzles passing through the same generatrix within one rotation period.

Claims

1. A method for controlling continuous and uniform spraying with variable flow rate on the inner wall of a frustum-shaped pipeline, which uses a spraying robot for spraying. The spraying robot includes a base, a nozzle support arm, a nozzle connecting arm, a nozzle rotating arm, and a spray gun. The base moves in a uniform straight line on the inner wall of the frustum-shaped pipeline; the nozzle support arm is connected to the base and moves up and down in a direction perpendicular to the base; the nozzle connecting arm is connected to the nozzle support arm, and the nozzle connecting arm rotates around one end of the nozzle support arm; the nozzle rotating arm is connected to the nozzle connecting arm, and the nozzle rotating arm makes a circular motion with the nozzle connecting arm as the rotation center; the spray gun is connected to the nozzle rotating arm, and the spray gun rotates around one end of the rotating arm; and the spray gun is telescopic. Its characteristics are that, It includes the following steps: Obtain the parameters of the spraying curved surface space shape of the inner wall of the frustum-shaped pipeline; Obtain the spraying production requirements according to the actual engineering needs; Calculate the spraying process parameters of the spraying robot according to the preset spraying parameters; the spraying process parameters are the speed of the spraying robot base, the telescopic speed of the support arm, the rotational angular velocity of the rotating arm, the telescopic speed of the nozzle, and the flow rate change function of the spraying robot; the formula for the flow rate change function of the spraying robot is: ； where t is the spraying time; H is the spraying thickness; ω is the angular velocity of the rotating arm; r1 is the radius of the end face with a smaller area; L is the total length of the pipeline; φ is the angle between the pipeline bus and the axis; T is the total spraying time; is the length of the rotating arm; h is the distance between the nozzle and the surface to be sprayed; θ is the divergence angle of the nozzle spraying; d is the spraying width; Control the spraying robot to spray the inner wall of the frustum-shaped pipeline according to the spraying process parameters and the spraying path.

2. The method for controlling the continuously uniform spraying with variable flow rate on the inner wall of a frustum-shaped pipeline according to claim 1, wherein The parameters of the curved surface space shape include the total length of the pipeline, the radius of the smaller end face, and the inclination angle between the pipeline axis and the generatrix.

3. The variable-flow continuous and uniform spraying control method for the inner wall of a frustum-shaped pipeline according to claim 1, wherein The spraying path is a spiral curve.

4. The method for controlling continuous and uniform spraying with variable flow rate on the inner wall of a frustum-shaped pipe according to claim 1, characterized in that, The telescopic speed of the support arm of the spraying robot is: 。 5. The method for controlling the continuously uniform spraying with variable flow rate on the inner wall of a frustum-shaped pipe according to claim 4, wherein, The rotational angular velocity of the rotating arm of the spraying robot is: ； Where n is the number of nozzles.

6. The method for controlling the continuously uniform spraying with variable flow rate on the inner wall of a frustum-shaped pipe according to claim 4, wherein The telescopic speed of the nozzle of the spraying robot is: 。

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