Flexible electronics are becoming the next generation of devices due to their advantages, such as mechanical flexibility, eco-friendliness, large-area applicability, and scalability for mass production. However, solution-based manufacturing processes are prone to defects like discontinuities and local smudging, which can significantly degrade both device quality and yield. To tackle these challenges, rapid and accurate defect classification is crucial for real-time diagnosis during manufacturing. This study investigates the impact of data scale and key training hyperparameters on the performance of deep learning–based defect diagnosis models, using a dataset of conductive pattern defects in flexible electronics. We specifically examine how the number of training images affects model accuracy and generalization, and we analyze how adjustments to hyperparameters—such as L2 regularization and dropout—influence model performance in data-limited scenarios. Our findings offer insights into optimal training strategies tailored to different data scales and learning constraints, providing practical guidelines for designing and developing AI-based defect diagnosis models for flexible electronic devices.
The use of environmentally friendly, lubricant-free plastic seals in the rotating parts of robots and machines is on the rise. However, variations in seal geometry and operating conditions can influence the contact pressure between the seal and shaft, potentially leading to poor sealing performance, premature wear, or debris ingress. Therefore, advanced design optimization is essential. In this study, we conduct a parametric study and sensitivity analysis to enhance the performance of plastic seals. Finite element analysis (FEA) is carried out using a 2D axisymmetric model with interference fit contact conditions to accurately simulate the behavior of the seal and shaft. We verify the reliability of the analysis by comparing the deformation of the seal diameter before and after shaft insertion with experimental measurements obtained using a 3D tactile measurement device. We analyze four design variables: pressure, temperature, seal diameter, and coefficient of friction, considering seal contact pressure as the objective function. Sensitivity analysis is performed to determine the impact of these design variables on contact pressure and to identify trends.
Industrial robot manipulators require high absolute position accuracy of the end effector to perform precise and complex tasks. However, manufacturing errors cause differences between nominal and actual parameters, and errors between the expected and actual positions of the end effector, resulting in undesired lower absolute position accuracy. Accordingly, to increase the absolute position accuracy of the end effector, kinematic calibration is required to correct the nominal parameters close to the actual parameters. However, in this study, redundancy of parameters may occur from the overlapping degrees of freedom of parameters in adjacent frames, which causes the problem of unnecessarily correcting many parameters in the optimization process. Thus, to solve this problem and use only the necessary parameters, this paper focuses on the linear relationship of redundant parameters and proposes a method of automatically discriminating and removing it through the Pearson Correlation Analysis. Additionally, through simulations on the two manipulator models, we verify the accuracy of redundancy of parameters determined by the proposed method, and demonstrate consistency and efficiency by comparing the results before and after redundancy removal.
Citations
Citations to this article as recorded by
Development of an Agile Robotic Fixture for Door Trim Fixation Jaesoon Lee, Sang Hyun Park, Jong-Geol Kim, Minseok Kang, Murim Kim Journal of Korea Robotics Society.2025; 20(3): 422. CrossRef
Robot Kinematic Calibration Using a 3D Scanner Won Bo Jang, Junyoung Lee, Jong Hoon Park, Seok Hyeon Yoon, Ui Hun Sagong, Myun Joong Hwang, Murim Kim Journal of Korea Robotics Society.2025; 20(3): 360. CrossRef
Shape memory alloy (SMA) has been widely used for many engineering and scientific applications, because it is largely deformable with high power density, and can be actuated easily by resistive heating. It is possible to reduce the size of the actuators by integrating or embedding SMA into the structures. While many applications have been reported regarding linear or bending actuators using the SMA wire, the development of a rotary actuator remains important and challenging for the engineering applications. Here, a new type of millimeter-scale rotary actuator is proposed based on the twisted SMA wires. SMA wires are twisted, folded, and integrated into the rotary actuator, and simple change of the twist direction enables the rotary actuator to rotate in the opposite direction. By integrating the oppositely twisted SMA wires into one rotary actuator unit, bidirectional rotary motions are possible. The actuation mechanism, design, and fabrication processes of the proposed rotary actuator are presented and demonstrated with its actuation performance. The fabricated actuators had average rotary working ranges from -38.68±4.92 deg to +45.37±8.79 deg in counterclockwise (CCW) and clockwise (CW) directions. This study will leverage the practical advances in the relevant engineering and scientific applications.
Citations
Citations to this article as recorded by
A Novel Force-Couple SMA Rotary Actuator for MEMS Safety and Arming Device Yun Cao, Zeyi Chai, Yikang Huang, Mo Yang, Hengbo Zhu, Weirong Nie, Zhanwen Xi IEEE Sensors Journal.2025; 25(19): 35879. CrossRef
Multi-field coupled dynamics for a movable tooth drive system integrated with shape memory alloys Lizhong Xu, Zhenglong Fu Heliyon.2023; 9(7): e17531. CrossRef
Design, Fabrication, and Control of a Rotary Manipulator driven by Twisted Shape Memory Alloy (SMA) Wires Gil-Yong Lee, Su-Yeon Lee Journal of the Korean Society for Precision Engineering.2023; 40(8): 665. CrossRef
Largely deformable torsional soft morphing actuator created by twisted shape memory alloy wire and its application to a soft morphing wing Su-Yeon Lee, Gil-Yong Lee Scientific Reports.2023;[Epub] CrossRef
The International System of Units (acronym: SI) is founded on seven base units (meter, kilogram, second, ampere, kelvin, mole, and candela) corresponding to seven base quantities (length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity). SI was formally established in 1960 by the 11th CGPM. It has been revised from time to time in response to requirements of users and advances in science and technology. However, the most significant revision is going to be done in November 2018 by the 26th CGPM. Four base units (kilogram, ampere, kelvin, and mole) will be given new definitions linking them to exactly defined values of Planck constant, elementary charge, Boltzmann constant, and Avogadro constant, respectively. In this paper, historical background for the revision of SI is described and scientific principle of redefinition is explained. The procedure used to redefine meter from the speed of light in a vacuum is used as an example. After this revision, uncertainties of many other fundamental constants will be eliminated or reduced. From May 20, 2019 (World Metrology Day), the revised SI will come to practice.
Citations
Citations to this article as recorded by
Time and Its Measure: Historical and Social Implications Paolo Vigo, Andrea Frattolillo Metrology.2023; 3(3): 294. CrossRef
Strategy Direction of the Quality Assurance System of Metrology according to the Change of Sensor and Measurement Technology Wan-Ho Cho, Sung Jung Joo, Hyung Kew Lee Journal of the Korean Society for Precision Engineering.2021; 38(12): 917. CrossRef
Three-axis magnetometers are widely used in various fields requiring azimuth information. However, accuracy of azimuth estimation based on magnetometer signals may be degraded because of errors such as offset, scale factor, nonorthogonality, hard-iron distortion, and soft-iron distortion. Recently, several ellipsoid-fitting calibration techniques have been proposed and have received much attention. However, comparative analysis of calibration accuracies between these techniques has not been conducted. This study compared and analyzed performance of four ellipsoid-fitting magnetometer calibration techniques such as the linear least square method, the two-step algorithm, and two different nonlinear least square methods. Our analysis and experimental results reveal superiority of the linear least square method compared to other methods in terms of calibration accuracy as well as ease of use in practice.
Citations
Citations to this article as recorded by
Real-time estimation of roll angles by magnetometer based on two-step adaptive Kalman filter Xiaofen Dong, Guoguang Chen, Xiaoli Tian, Xiaolong Yan Measurement.2022; 198: 111349. CrossRef
Dynamic Accuracy Improvement of a MEMS AHRS for Small UAVs Min-Shik Roh, Beom-Soo Kang International Journal of Precision Engineering and Manufacturing.2018; 19(10): 1457. CrossRef
This paper aims to verify the reliability of the creep-life assessment regarding the STS304H-Type tube for which the hardness method of H. Tanaka is used. For this purpose, the creep-rupture test and the hardness test were conducted with a new tube and used tubes that were exposed to 96,000 hr under a 650oC condition. The hardness value of the used tubes is higher than that of the new tube by approximately 12 Hv to 15 Hv. This test result was applied to the creep-life assessment of the STS304H-Type for which the H. Tanaka hardness method was used, and the life consumption of the used tubes was evaluated as 13%. The rupture times of the new and used tubes are 802 hr and 707 hr, respectively. The use of the test results as a substitution of the results of the Larson Miller Parameter for a life-assessment tool produced a life-consumption calculation of approximately 12%. Similar results can be confirmed between the Larson Miller Parameter method and the hardness method.
First
Prev
