Research on Optimization of Uniformity of Robot Spraying Coatings for Changing Positions on Convex and Concave Characteristic Surfaces

doi:10.3969/j.issn.1004-132X.2025.11.027

Abstract

Abstract:

Aiming at the problems of optimizing coating uniformity in surface spraying involving convex and concave features， a novel spraying trajectory optimization method was proposed based on incorporated posture changes during the spraying processes. The effects of geometric parameters associated with convex and concave surfaces on coating uniformity during both vertical and variable posture spraying were studied， suitable bulge heights and depression depth ranges for the vertical spraying technique were identified. Subsequently， for convex and concave features that were incompatible with vertical spraying， a continuous variable inclination angle spraying trajectory optimization method utilizing arc transitions was introduced. Finally， a continuously variable inclination angle coating thickness model and an optimization target model were developed to enhance coating uniformity on surfaces with convex and concave features. Simulation and experimental results demonstrate that， compared to the vertical spraying method， the applications of the proposed technique to surfaces with convex and concave features result in a 41.06% reduction in the standard deviation of film thickness and a 15.23% increase in the proportion of areas meeting the required film thickness accuracy.

Key words: spraying robot, variable inclination angle spraying, trajectory optimization, convex and concave feature, film thickness accuracy

摘要：

针对凸起凹陷特征表面喷涂的涂层均匀性优化问题，提出了一种基于变位姿喷涂工艺的喷涂轨迹优化方法。研究了垂直喷涂和变位姿喷涂时凸起凹陷几何参数对涂层均匀性的影响规律，并探讨了适用垂直喷涂方法的凸起高度和凹陷深度范围；针对不适用垂直喷涂的凸起凹陷特征，提出了一种采用圆弧过渡的连续变倾角喷涂轨迹优化方法；最后，建立连续变倾角涂层厚度模型和优化目标模型以提高凸起凹陷特征表面的涂层均匀性。仿真与实验结果表明，相较于垂直喷涂方法，所提出的方法应用于凸起凹陷特征表面时，膜厚标准差降低41.06%，能满足膜厚精度要求的区域占比提高15.23%。

关键词: 喷涂机器人, 变倾角喷涂, 轨迹优化, 凸起凹陷特征, 膜厚精度

CLC Number:

TP242

Yao DAI, Yong ZENG, Xueya ZHAO, Junhao WAN, Jintong GU, Xinyi ZHU. Research on Optimization of Uniformity of Robot Spraying Coatings for Changing Positions on Convex and Concave Characteristic Surfaces[J]. China Mechanical Engineering, 2025, 36(11): 2694-2703.

戴尧, 曾勇, 赵雪雅, 万俊豪, 顾金彤, 祝欣怡. 凸起凹陷特征表面的机器人变位姿喷涂涂层均匀性优化研究[J]. 中国机械工程, 2025, 36(11): 2694-2703.

Figures/Tables 17

Fig.1 Spray plume model and the coating growth rate model

Fig.2 Schematic diagram of the calculation model for the spray gun inclination angle

Fig.3 Schematic diagram of the protrusion and depression characteristics in vertical spraying

Fig.4 Schematic diagram of complex feature spraying with a continuously varying inclination angle trajectory

Fig.5 Schematic diagram of external corner spraying

Fig.6 Schematic diagram of internal corner spraying

Fig.7 Schematic diagram of the coating at the junction of external corners

Tab.1 Optimal spraying velocity at varying protrusion heights and depression depths

凹陷特征	d₂/mm	40	47	50	60
凹陷特征	v $c *$ /（mm·s^-1）	254.1	266.4	278.2	299.2
凸起特征	d₂/mm	50	52	60	70
凸起特征	v $c *$ /（mm·s^-1）	292.1	302.3	314.8	336.5

Tab.1 Optimal spraying velocity at varying protrusion heights and depression depths

凹陷特征	d₂/mm	40	47	50	60
凹陷特征	v $c *$ /（mm·s^-1）	254.1	266.4	278.2	299.2
凸起特征	d₂/mm	50	52	60	70
凸起特征	v $c *$ /（mm·s^-1）	292.1	302.3	314.8	336.5

Fig.8 Influence of varying protrusion heights and depression depths on coating thickness

Tab.2 Optimal spraying parameters for spray trajectories at varying protrusion heights and depression depths

d₂/mm	H_z0/mm	H_z1/mm	R₁/mm	R₂/mm	v₁/ （mm·s^-1）	v₂/ （mm·s^-1）	v₃/ （mm·s^-1）	v₄/ （mm·s^-1）	v₅/ （mm·s^-1）	v₆/ （mm·s^-1）
47	220	165	231	32	431.3	317.1	354.1	356.2	274.8	304.4
50	216	162	221	43	398.3	309.8	343.4	309.5	246.4	294.7
52	213	166	218	24	235.1	291.3	261.5	299.6	360.4	401.2
60	210	164	216	35	218.2	314.4	253.1	291.2	351.8	382.7

Fig.9 Optimized coating thickness distribution

Fig.10 Effects of vertical and positional variation spraying on minimum and maximum coating thickness

Fig.11 Schematic diagram of robotic spatial spraying trajectory

Fig.12 Spraying experiments on sheet materials

Fig.13 Measurement of coating thickness on sheet materials

Tab.3 Spraying experimental results using different trajectory planning methods

实验结果	凸起特征板材		凹陷特征板材
实验结果	垂直喷涂	连续变倾角喷涂	垂直喷涂	连续变倾角喷涂
满足膜厚精度要求的区域占比/%	86.1	100.0	87.5	100.0
平均膜厚/μm	46.2	48.9	46.2	48.2
膜厚标准差/μm	5.3	3.2	4.7	2.7

Fig.14 Comparison of coating thickness between spraying experiments and simulation studies

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