In this paper, the profile of the bar is detected by laser vision technology. During the detection process, obvious isolated outliers can be observed in the profile data; dimension parameter and profile-fitting accuracy are seriously affected by these outliers. In order to eliminate these outliers and improve the measurement accuracy, this paper uses Hampel identifier and moving mean identifier to identify isolated outliers. At the same time, the profile data is fitted, and the fitting results and fitting accuracy were analyzed and compared between the original data and the renovated data. The experiment proves that the outliers in the data must be identified and processed in the data measurement process. The Hampel identifier has better recognition effect, its algorithm is simple, efficient, and robust, and it can play an important role in the preprocessing of profile data based on structured light.
1 September 2018 in Applied Mathematics and Computation
Section flattening often occurs in the hot bending process of magnesium alloy tube with large curvature. In order to control the forming quality of the tube, it is necessary to measure the section profile of the magnesium alloy pipe online. In this paper, the laser vision system is used to measure the profile of magnesium alloy tube. Due to the influence of the environment and the surface quality of the pipe, there are obviously isolated outliers in the profile data, which seriously affects the accuracy and precision of the tube measurement. An outlier identification algorithm based on robust locally weighted regression and PaйTa criterion is proposed. This algorithm is used to identify the typically isolated outliers in the measurement process and discuss its identification ability. Meanwhile, it is compared with the moving mean identifier and the Hampel identifier. Subsequently, the ellipse fitting of profile data was carried out, and the fitting ellipse parameters and fitting precision of the curved section were obtained. At the same time, the fitting results were compared before and after the outliers are eliminated. The experiment proves that the outlier identification method based on robust locally weighted regression and PaйTa criterion can effectively identify outliers in profile data, especially for spot outliers. This algorithm is a robust, accurate, and efficient outlier identification method, which can effectively improve the laser profile measurement accuracy of the pipe section and has great significance for the quality control of magnesium alloy tube.
Tunnel lighting cleaning is of significant practical importance for improving driving safety. To address the low operational efficiency of tunnel lighting cleaning tasks, a trajectory planning method based on the chaotic adaptive whale–particle swarm optimization (CAW-PSO) algorithm is proposed. Taking the SIASUN GCR16-2000 robotic arm as the research object, the trajectory is constructed using a 3-5-3 polynomial interpolation, with the objective of achieving time-optimal trajectory planning. In the CAW-PSO algorithm, a tent chaotic map is introduced to improve the quality of the population; a linearly decreasing inertia weight is designed to strike a balance between local and global search; dynamic learning factors are defined to strengthen the individual learning ability and global cognitive capability of particles; finally, the exploitation mechanism of the whale optimization algorithm is employed to avoid getting trapped in local optima and improve convergence accuracy. The simulation time is 3.661 s, a reduction of 69.94%. The experimental results yielded a mean relative error of 1.16%, indicating good agreement with the simulation results. The results of the simulation and experiment indicate that the CAW-PSO effectively reduces the motion time of the robotic arm, exhibiting superior applicability in trajectory planning for tunnel lighting cleaning robotic arms.
2 July 2025 in Highlights in Science, Engineering and Technology
As a core surface treatment process in modern industry, electrostatic powder spraying technology demands high coating quality; however, integrated spraying-plastering robots frequently encounter powder accumulation issues in electrostatic devices and nozzles, adversely affecting spraying efficiency, coating uniformity, and equipment lifespan. This study establishes a three-dimensional nozzle model using SolidWorks, and employs ANSYS FLUENT for multiphysics coupling simulations to analyze structural deficiencies in the original design and propose rational optimization schemes. By reconstructing the single-beam electrostatic device into three slender beams arranged in an equilateral triangular distribution (1 mm in width) and adopting a conical inner cylinder design, the gas flow characteristics and powder distribution uniformity are significantly improved. Static analysis shows that the maximum stress of the optimized nozzle is reduced from 0.2627 MPa to 0.1436 MPa, with deformation decreased by 59.8%, which is far below the material's safety threshold. Fluid dynamics simulations verify the airflow stability of the optimized structure; both single-phase flow and discrete phase models demonstrate a 31% improvement in the uniformity of outlet velocity distribution, with reduced powder retention. This study offers valuable insights for the high-efficiency and low-energy-consumption design and structural optimization of integrated spraying-plastering robot nozzles.