Spray Path Research Articles

Path Planning for Spray Painting Robot of Horns Surfaces in Ship Manufacturing

Generating paint gun path for complex free-form surfaces in shipbuilding industry to ensure uniform paint deposition is highly challenging due to their complex geometry, especially for horns surfaces. In this paper, a tool trajectory optimization method was proposed based on dip angle spray in order to solve the problems of poor coating uniformity and material waste for spraying horns surface with curved patches. A dip angle spray model was developed based on the Beta distribution model on the planar surface by principle of differential geometry. The spray path optimization models for dip angle spraying on cylindrical surfaces of three cases were proposed and compared first to define the best case which yields the best painting quality. Then we used the best strategy on a horns surface in a shipyard to evaluate the effectiveness and robustness of designed algorithm. This algorithm can also be extended to other applications.

Parameter Settings for an Automated Gantry-Robot Painting System using a 3-Gun Atomization Spray Method for an Anti- Static Coating Process

Dry film thickness and appearance are the main quality improvements that can be achieved by an automated painting system in the manufacturing process. This study presents the spray coating process for aircraft parts using a gantry robot with an automated spray-painting gun to control the spray path, thus achieving the desired coating layer thickness. The experimental results show that the 3-gun atomization spray method, with high capacity airflow and outstanding atomization characteristics, poses the challenge of achieving an even thickness of the overlapping spray pattern from three separate guns, minimizing the paint material consumption and controlling the dry film thickness within the given specification and standard. The optimization was performed to control the spray path and material consumption with a 3-gun spray method to achieve the optimum setting for the spray nozzle to workpiece height to obtain the target thickness. The results show that replacing the manual process with the automated painting process can increase the speed by up to 30-40%, reduce the setup time and increase the capacity of the painting booth. The development of this system can achieve the desired thickness specification, increase productivity and provide safer, more effective and ergonomic working conditions.

Research on Spray Trajectory Atomization Based on Mathematical Analysis

The most important part of the spraying process is the paint film thickness uniform and how to plan the spray path. The paper is optimize the trajectory of spray gun by establishing mathematical model. Based on the analysis of the factors affecting the thickness distribution of paint film, establishing the thickness of single-trajectory spraying model, and analysis the relationship and surface geometry invariant to simplified the model, getting the optimal solution by using overlapping thickness model based on the movable surface, useing MATLAB to establish model of the curve surface. Then using projection to establish the thickness distribution model of any curve surface. Then use cloud sectioning to optimize the curve surface and establish the thickness of paint film in double trajectory.

Optimized Combination of Spray Painting Trajectory on 3D Entities

In this research, a novel method of space spraying trajectory optimization is proposed for 3D entity spraying. According to the particularity of the three-dimensional entity, the finite range model is set up, and the 3D entity is patched by the surface modeling method based on FPAG (flat patch adjacency graph). After planning the spray path on each patch, the variance of the paint thickness of the discrete point and the ideal paint thickness is taken as the objective function and the trajectory on each patch is optimized. The improved GA (genetic algorithm), ACO (ant colony optimization), and PSO (particle swarm optimization) are used to solve the TTOI (tool trajectory optimal integration) problem. The practicability of the three algorithms is verified by simulation experiments. Finally, the trajectory optimization algorithm of the 3D entity spraying robot can improve the spraying efficiency.

Planning Method of Offset Spray Path for Patch considering Boundary Factors

To solve the problem of paint waste at the boundary of the patch when spraying, a planning method of offset spray path considering boundary of the patch is developed. By analyzing the causes of excessive paint waste at the boundary of the patch, a spray path planning method based on boundary curve of the patch is proposed, and the distance between the spray path and the boundary of the patch is optimized to reduce excessive paint waste. According to the allowable range of the spray height and the error range of the coating thickness, the variable range of the spacing distance is established; on this basis, the equal division method of plane intercept line is used to generate the discrete points of the spray path in the length direction of the patch, and a connection algorithm of the discrete points is used to generate the spray path of the patch. The simulation results show that the method can automatically generate a spray path based on the shape of the patch boundary; under the premise of meeting the uniformity requirements of the coating thickness, paint waste can be effectively reduced during spraying.

Fringe Pattern Based Plane-to-Plane Visual Servoing for Robotic Spray Path Planning

Robotic spray path planning is still a challenging task for large-scale structures because deformation is difficult to consider in conventional path planning, which can lead to the nonuniformity of paint film. To overcome this problem, a visual servoing approach based on fringe pattern projection is proposed to optimize the robotic spray path in this paper. In this method, the spray gun orientation is optimized to be perpendicular to the part surface at a desired distance during the spray procedure. Due to the textureless property of the surface of large-scale structures, the fringe pattern is shot onto the surface; thus, the deformed pattern directly reflects the position and orientation of the robot end-effector. Simulation experiments and real scenarios are used to demonstrate the validity and robustness of the proposed method. The results show that the proposed method would make automatic spray painting more feasible for large-scale structures.

Robotic Fire Suppression Through Autonomous Feedback Control

A computer vision-based autonomous fire suppression system with real-time feedback of fire size and spray direction is presented in this paper. The system has been developed for use in a firefighting robot for close-range, localized fire suppression tasks in enclosed environments. A probabilistic water classification method was developed for segmenting water spray in a pair of IR cameras. Stereo processing was performed to localize points along the spray path for use in yaw and pitch angle estimation. A Golden Section Search with linear least squares optimization was used to determine the optimal pitch angle of the spray position at each sampling time. Kalman filtering was used to remove noise from the angle measurements and obtain a better estimate of the current nozzle orientation. A decision tree was used to determine the correct nozzle positioning mode using image feedback to suppress the fire and accounts for errors in direction, fire size during suppression, and when to adjust the nozzle based on IR feedback. Through implementation of a PI controller, the system is able to correct for unknown disturbances causing erroneous targeting of a localized fire. Experiments are presented with the initial nozzle angled correctly and with forced offsets in the system to set the initial spray position incorrectly in order for the system to correct. Suppression times ranged from 7.2 s to 16.3 s with a standard deviation of 3.9 s and average time of 11.2 s. A total of 12 tests demonstrated performance of the system given a forced offset to the initial nozzle orientation resulting in an error between the spray location and the fire target. Suppression times ranged from 8.1 s to 27.9 s with a mean of 16.9 s and standard deviation of 6.2 s. The proposed system can be implemented on a robotic firefighting platform to autonomously detect a fire, choose a proper manipulation goal and suppress full scale fires given disturbances causing erroneous targeting.

基于虚拟仿真的热喷涂轨迹规划方法

热喷涂技术是表面工程领域内表面改性最有效的技术之一。本文在分析热喷涂系统组成与工艺参数的基础上，从虚拟环境构建、机器人建模及喷涂轨迹仿真等方面给出了面向工件表面热喷涂的机器人轨迹规划方法，并通过某型叶片表面轨迹规划的实例分析，验证了方法的有效性、可行性。 Thermal spray is one of the efficient technologies that is used for surface treatment. The parameters of thermal spray is analyzed, the virtual environment is established, the spray robot model is presented, the spay path is simulated and the approach for path planning of thermal spray is pro-posed based on virtual simulation. A case study of blade surface spray path planning is provided which indicates that the approach proposed is valid and feasible.

Damage evolution of a thermal barrier coating system with 3-dimensional periodic interface roughness: Effects of roughness depth, substrate creep strength and pre-oxidation

Damage evolution during thermocyclic loading of atmospheric plasma sprayed thermal barrier coating (TBC) systems with 3-dimensional (3-D) periodical quadratic, hexagonal and stochastical interface roughness was compared. Furthermore, effects of roughness depth, substrate creep strength and pre-oxidation were investigated. As substrates planar Fecralloy EisenChrom™ was used. The samples with periodical hexagonal roughness showed on average near cubic oxidation kinetics and faster oxidation at the roughness valleys than at the peaks. The coatings on all samples with 3-D quadratic roughness failed immediately after TBC-deposition. For the other profiles excessive segmentation and continuous crumbling of the TBCs occurred. However, the coatings mostly did not spall-off during 836 oxidation cycles. Thermography permitted to detect <1mm diameter spot-shaped initial delaminations (IDs) that formed during thermal cycling. With progressive cycling their number and area increased until they merge. The positions where IDs formed correlated with locally larger TBC thicknesses associated with the spray path during TBC deposition. Samples with pre-deposited oxide layer showed significant larger delamination areas after thermal cycling. Sample bending towards the TBC and deformation of the substrate below the TBC occurred, indicating stress relaxation. Despite the partially large delaminations, this relaxation led to the prevention of macroscopic TBC detachment and large area spallation till the end of the thermal cycling tests. Cross-sections of the 3-D periodic roughened samples revealed no effect of the roughness depth on the amount of cracking or on damage evolution after certain cycle numbers.

Aerial Method of Plant Protection with the Use of an Autogyro for Sustainable Agriculture

Abstract Despite the limitations in the use of aerial applications resulting from Directive 2009/128/EC of the European Parliament and of the Council and the Plant Protection Agents Act (OJ L item 455. 2013), scientific progress in engineering enables the development of new, environmentally safe technologies to expand the use of agroaviation. This paper proposes an innovative method of biological protection of corn against Ostrinia nubilalis with the use of an autogyro and presents the results of these operations. An autogyro adaptation for forest applications is proposed, and the preliminary results of a spray uniformity assessment are presented. Based on a two-year study (542.5 ha), the introduction of the Tricholet preparation against Ostrinia nubilalis was found to be highly effective (73.55%), which is a positive indication for the innovative autogyro method for introducing Trichogramma evanescens. Similarly, positive results were obtained for a liquid agent application using an autogyro-mounted installation: an even coverage of the area was achieved across the entire spray path width while maintaining the required dosing of the plant protection agent.

Evaluation of Cold and Thermal Fogging Spraying Methods for Mosquito Control.

The efficacy of three pyrethroid insecticides (lambda-cyhalothrin, deltamethrin, and cyphenothrin) in cold (CF) and thermal fogging (TF) applications against caged adults of Culex pipiens Linnaeus were evaluated under hot-dry conditions in Riyadh, Saudi Arabia. The efficacy of CF and TF at different distances from the release point (15, 30, 45, and 60m) and height (1 and 2m) was also investigated by evaluating adult mortality after 24h of exposure. Our data indicated that TF was more efficacious than CF. While the distance from the spray path did not affect TF efficacy, CF showed decreased efficacy with the increase in distance from the spray path. Deltamethrin efficacy was significantly affected by both the application method and distance from the spray path, whereas lambda-cyhalothrin was only affected by the spray method.

Path Optimization of Spray Painting Robot for Zigzag Path Pattern

in order to solve the coating uniformity of common border between two patches based on zigzag path pattern, an algorithm of zigzag path is developed. In this paper, a complex free surface is divided into several patches based on the constraint of coating thickness error. Based on optimized parameters of spray path on a patch, an algorithm that using variable path parameter is used to optimize zigzag path pattern by modifying the planning direction of paint gun path when satisfy parallel condition. The results of simulations have shown that the path planning algorithm achieves satisfactory performance.

Effect of Wall Configuration on Atomization of Rapeseed Oil Diesel Spray Impinging on the Wall

Fuel-air mixing is important process in diesel combustion. It has been well known that wall configuration of the piston affects spray atomization. Biomass fuel, that is viable alternative fuel for fossil one, needs great help of mixing to atomization because the fuel has high viscosity and high distillation temperature. This study investigates spray atomization characteristics of rapeseed oil (RO) when it impinges on the piston wall. Optical observation of RO spray was carried out using shadowgraph photography technique. The optical images and image analysis show that wall impingement effectively promotes RO spray atomization. Spray atomization is more sensitive to wall configuration for RO than diesel fuel. The wall that has flat floor at the bottom can improve atomization. It is necessary for RO spray to promote spray penetration followed by wall-impingement because long spray path offers wide spray boundary region to form droplets.

Liquid attachment and momentum transfer by collisions between free-fall solids and liquid spray droplets

Abstract Understanding solid wetting by collisions between flowing solids and spray droplets is essential to optimizing the design and operation of related industrial processes. This paper presents an innovative experimental method to identify the statistical distributions of liquid attachment and collision probability of the impingement of a liquid spray onto free-fall particles. To separate liquid attachment from other contributions to the mass measurements of particles and liquids, individual impingement experiment with hydrophobic or hydrophilic particles of the same otherwise properties is respectively performed under the same conditions. In addition, a series of collection bins are distributed along the spray path to determine the statistical probability of collision properties including coating thickness. Based on these measurements, the collision-induced momentum transfer and velocity redistribution of solids and droplets can be estimated with the aid of a Lagrangian trajectory model. Consequently a general two-parameter of collision probability density function is proposed.

Research on the Characteristic of Diesel Elastic-Plate Impingement Spray

A series of experimental research results on the characteristic of diesel elastic-plate impingement spray using High Speed Photography camera are presented in this paper. The experiments were carried out in a constant volume chamber specially designed, which can hold a high ambiance pressure. The special fixed device was designed so that the elastic-plate can be fixed on the spray path, meanwhile the spray incident angle and height can be changed. The free jet spray and elastic-plate impingement spray was compared under the same experimental condition including different injection pressure and different background pressure. Experimental research showed that impingement spray droplets diffuse more quickly than free jet spray.

Research on the Characteristic of Diesel Elastic-Plate Impingement Spray

A series of experimental research results on the characteristic of diesel elastic-plate impingement spray using High Speed Photography camera are presented in this paper. The experiments were carried out in a constant volume chamber specially designed, which can hold a high ambiance pressure. The special fixed device was designed so that the elastic-plate can be fixed on the spray path, meanwhile the spray incident angle and height can be changed. The free jet spray and elastic-plate impingement spray was compared under the same experimental condition including different injection pressure and different background pressure. Experimental research showed that impingement spray droplets diffuse more quickly than free jet spray.

Shop Primer의 다중 노즐 분사 스프레이 패턴 인자와 도막두께의 상관관계에 관한 연구

Multi-nozzle spray painting procedure of the inorganic zinc shop primer was established in order to obtain uniform film thickness. The shop primer paint prevents the corrosion of steel block during shipbuilding. When the dry film thickness of shop primer is insufficient, rust will be generated on the steel block. Otherwise, thick coating of shop primer may be a problem of weld defect. So, it is important to obtain the uniform film thickness of shop primer. The uniformity of dry film thickness is affected by spray speed, distance from spray gun to target surface and overlapping span of spray path. In order to uniformly maintain coating thickness of shop primer, the coating procedure was established based on the correlation of shop primer spray variables.

Impacts of Ultra-Low Volume Resmethrin Applications on Non-Target Insects

We studied the impacts of exposure to ultra-low volume (ULV) applications of resmethrin (Scourge) on monarch butterfly (Danaus plexippus) larvae and adults. In a series of 3 experiments, we measured short- and long-term survival of monarch larvae and adults, and the impacts of consuming previously exposed host plants on monarch larvae. We measured efficacy during all experiments with caged sentinel mosquitoes, and during Experiments 1 and 2 with pretreatment, treatment, and posttreatment measurements of mosquito abundance in CO2 traps. Downwind monarch larval and adult mortality were higher than upwind or control mortality up to 120 m, but not 170 m, from the spray path. In 1 experiment, monarchs exposed to spray as larvae developed into smaller adults, suggesting sublethal impacts. Milkweed host plants sprayed 1, but not 2 or 4 days previously, resulted in increased monarch larval mortality. Sentinel mosquito mortality was generally high, and CO2 traps revealed substantially lower mosquito abundance immediately after the treatment (>90% reduction) but <20% reduction 24 h after treatment. Our results suggest that ULV resmethrin applications will impact lepidopteran larvae and adults that are directly exposed to the spray but that generalizations about other nontarget taxa will require additional research. The magnitude of population-level impacts on monarchs will depend on the proportion of the population that is exposed.

Random discontinuous carbon fibre preforms: Permeability modelling and resin injection simulation

Abstract The distribution of fibre bundles in chopped carbon fibre preforms was described using a stochastic model, as a function of geometrical and preform processing parameters. Local permeability distributions were generated from this, based on Gebart’s model for the permeability of aligned fibres. Resin injection simulations were evaluated statistically based on these permeability distributions. Results indicate that, as expected, the macroscopic preform permeability decreases with increasing superficial density (i.e. the average fibre volume fraction). It is independent of the tow filament count and the fibre length within the ranges investigated. The observed coefficient of variation of the permeability increases with increasing filament count, fibre bundle length and superficial density. At constant preform superficial density, variation of the preform processing parameters (fibre spray path offset, spray tool elevation, and spray path pattern) affects the fibre bundle distribution and thus the flow front patterns. Different combinations of the processing parameters have different effects on the mould fill times.

Experimental study on macroscopic spray characteristics after impingement in a slit-type GDI injector

In this paper, an experimental study on the wall-impinging spray of the slit-type GDI injector is presented. To examine the effects of various factors on the development of a spray impinging on the wall, experiments were conducted at various injection pressures, ambient pressures, wall distances from the injector tip, wall temperatures, and wall inclination angles. Behavior of the impinging spray was visualized using a planar laser scattering method. It is shown that the spray path penetration of the wall-impinging spray increases with increases in injection pressure, wall distance, wall temperature, or wall angle. On the other hand, the spray path penetration of the wall-impinging spray decreases with increases in ambient pressure. The predicted spray path penetration calculated by the empirical equation estimates the spray path penetration in all cases, and the empirical equation is optimized for the total injection pressure.