In machining operations, dynamometers are typically used to directly measure the forces acting on cutting tools. However, their high cost and complex setup restrict their use to laboratory environments, making them unsuitable for real-time monitoring in general production settings. To overcome this limitation, this study proposes an autoencoder-based learning model for estimating cutting forces using only spindle vibration signals acquired during milling. The model features a deep neural network (DNN) that takes processed spindle vibration signals as input and predicts latent features derived from cutting force signals through an autoencoder. These predicted latent features are then fed into a pretrained decoder to reconstruct the corresponding cutting force signals. To enhance the model's accuracy and robustness, the raw vibration signals sampled at 20 kHz were filtered with a bandpass filter that spans the effective frequency range of 20–2500 Hz, effectively removing irrelevant noise. For validation, an accelerometer was mounted on the spindle head of a milling machine, and vibration data were collected during cutting. The estimated cutting forces were compared to ground truth measurements obtained from a dynamometer. The model achieved a Pearson correlation coefficient of 0.943, demonstrating that reliable cutting force estimation is achievable using only low-cost vibration sensors.
This study evaluates the structural design and safety of the CanSat in launch environments. The CanSat serves as an educational replica satellite, allowing users to experience the design and operation of small satellites. To ensure stable operation during launch, the structural analysis and design must consider external forces, including vibration and acceleration loads. We determined the material properties for the structure and conducted modal and random vibration analyses, comparing the results with launch environment data from NASA, ECSS, Falcon 9, and Soyuz-2. Additionally, we performed an acceleration load analysis using actual data from CanSat launches during competitions. The modal analysis indicated that the first natural frequency was 65.34 Hz, which exceeds the required threshold. The random vibration and acceleration load analyses further confirmed the structural safety of the design. While the data from NASA and ECSS were conservatively set, reflecting higher vibration intensities, the Falcon 9 and Soyuz-2 launch vehicles provided relatively lower vibration environments due to differences in their designs. Overall, the results demonstrate that the CanSat's structural integrity is maintained under the conditions analyzed for Falcon 9 and Soyuz-2.
With rapid growth of the global electric vehicle market, interest in the development of secondary batteries such as lithium batteries is also increasing. Core functional parts of secondary batteries are known to determine the performance of these batteries. Micro cracks, scratches, and markings that may occur during the manufacturing process must be checked in advance. As part of developing an automated inspection system based on machine vision, this study optimized the design of a linear feeder exposed to an environment with a specific operating frequency continuously to transfer parts at a constant supply speed. Resonance can occur when the natural frequency and the operating frequency of the linear feeder are within a similar range. It can negatively affect stable supply and the process of finding good or defective products during subsequent vision tests. In this study, vibration characteristics of the linear feeder were analyzed using mode analysis, frequency response analysis, and finite element analysis. An optimal design plan was derived based on this. After evaluating effects on vibration characteristics for structures in which vibrations or periodic loads such as mass and rails were continuously applied, the shape of the optimal linear feeder was presented using RSM.
Military equipment such as large radar system is difficult to transport because protecting each of inner components is mandatory. Therefore, a large radar system is basically transported by military vehicle and consider safety about transportation vibration during design procedure. However, in this paper, a large radar system which includes a large radar and cooling unit is transported by a commercial truck, not military, using different mounting methods so that analyzing acceleration is necessary in terms of verifying safety about transportation vibration. In addition, PSD data which is measured during a variety of transport environment explains that air suspension can absorb vibration efficiently and input vibration is small compared to the MIL-STD-810H, as such most amount of vibration from road can be damped and small energy would be transferred to upper equipment through load path, chassis to equipment. Furthermore, specific mounting method fasten a large radar system effectively. As a result, using a commercial truck with mounting methods during transportation large radar system is totally safe from transportation vibration.
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Structural Design and Analysis of a Quadcopter Type CanSat for Diverse Launch Conditions Yongseon Lee, Hyeongyu Lim, Hyeonchang Yang, Changbeom Choi, Jinsung Rho Journal of the Korean Society for Precision Engineering.2026; 43(1): 29. CrossRef
Inertial navigation technology originally designed for precise guidance of missiles is widely used in weapon systems. Guided missiles have become supersonic and high maneuverability with advancement of science and technology. Antivibration performance against high vibration and shock energy is accordingly required. Sensors of an Inertial Navigation System (INS) have a high sensitivity. Conversion coefficients for acceleration values and bias errors in signals must be minimized. A vibration isolator is generally applied to protect INS by attenuating the vibration and shock energy transmitted from dynamic disturbances. The stiffness and damping are changed using highly damped materials such as elastomers that must be protected from disturbances. A vibration isolator is widely used in various fields. However, it is important to understand characteristics of a vibration isolator composed of elastomer because it has nonlinearities such as hyperelasticity and viscoelastic as well as damping characteristics. In this study, a COTS vibration isolator suitable for INS was selected through theoretical approach. Response characteristics of the system in a vibration and shock environment were analyzed through FEM analysis and vibration and shock test. In addition, through repeated excitation test, reproducibility and structural stability were confirmed when the vibration isolator was installed in the system.
Development and research on electric vehicles in power transmission system are increasing as the demand for ecofriendly and autonomous vehicles increases across the industry. In order to reduce noise, research on high efficiency and low noise due to electrification of the gearbox system is being actively conducted, such as applying design technology to optimize the shape of the gear and increase rigidity. In particular, research on low noise is active because the noise of the electric gearbox could be easily recognized in a vehicle, even with small noise due to its frequency characteristics. Therefore, in this study, effects of main specifications of gears on noise and power loss were studied and analyzed through a Parametric Study. Characteristics of the proportional relationship between noise and power loss according to major specifications were analyzed. Based on study results, NVH analysis in the gear system was performed. After that, actual data were secured through test measurements and a noise reduction effect of 4.4 dB was confirmed.
This paper proposes a new rotary welding torch with a ball-jointed mechanical seal structure that simultaneously realizes the enclosure of CO₂ gas, the energization of welding current, and the insulation for system protection. In order to effectively compare the operation mechanism of the proposed device with the conventional rotary welding torch, a schematic technique is introduced to clearly visualize the operation and connection structure of the model. The kinematic state and constraint degrees of freedom of the tool are clearly shown, and it is easy to distinguish between the two designs that use different component parts and connection structures but result in the same final motion. In addition, the four dynamic characteristics of a rotary torch operating at 20 Hz (driving torque, vibration reaction force, natural frequency, and inertial mismatch) were analyzed to demonstrate superior performance to conventional products. The welding test showed that the tool normally operated even in a harsh welding environment, verifying its applicability in the field.
With advancements in the 3D printing technology, many industrial sectors are transitioning from traditional production methods, such as cutting processing, and casting, to utilizing 3D printers for manufacturing. For instance, in the automotive industry, the production of vehicle upright knuckle parts typically involves casting followed by machining processes, such as turning and milling, to achieve dimensional accuracy. However, this approach is associated with high processing costs and longer lead times. This study focuses on the production of vehicle upright knuckle parts using a selective laser melting (SLM)-type 3D printer, with SUS 630 as the material. To evaluate the feasibility of utilizing this method in industrial vehicles, this study conducts static and modal analyses, along with topology optimization. Additionally, experimental test drives are performed with the parts installed in KSAE BAJA vehicles, and modal frequency experiments are conducted. The objective of these analyses and experiments is to assess the performance, reliability, and applicability of utilizing SLM-based 3D printing for manufacturing vehicle upright knuckle parts by optimizing the design through topology optimization and evaluating the results through experiments and analysis.
As electrification trends for the automotive industry have accelerated and the demand for high efficiency has increased, hybrid transmissions have been pushed to enlarge the operating range of EOP. And in conventional transmissions, an Idle Stop and Go (ISG) EOP is becoming imperative. The operating conditions of the ISG EOP make it difficult to gain advantages by masking the effects of engine firing or drive noise. Thus, it is necessary to study noise in operating ISG EOPs. Also, the EOP inner components require precise processing and manufacturing because they should be made to a compact size owing to vehicle layout limitations. This paper first describes the results of an experimental study on the abnormal vibration phenomenon, which makes EOP operating noise worse. And secondly it was investigated the cause of abnormal vibration phenomenon which occurs due to processing and manufacturing problems in the process of developing the operating noise of the EOP for ISG on FF type automatic transmission. Finally, the verification results after improvement were described.
The purpose of the study was to evaluate the lumbar mobility and flexibility by the vertical vibration stimulation. The subjects were 21 young adults were divided into vibration group (n = 7) that applied 30 Hz vibration stimulation to the lumbar, foam roller group (n = 7) that relaxes the lumbar muscles with a foam roller, and good morning exercise group (n = 7) that stimulates the lumbar spine with the good morning exercise. The muscle strength, EMG and the sit & reach test were measured, to evaluate the lumbar mobility and flexibility before and after exercise intervention in each group. Results showed increasing in the vibrating group in muscle strength and EMG, and the good morning group and the vibrating group in the Sit & Reach test. This can be developed as a new alternative to exercise therapy for spine rehabilitation.
This paper presents an improved input shaping method to eliminate vibration during circular interpolation of a flexible 2-axis positioning system. Due to the time delay introduced by input shaping, simultaneous 2-axis positioning with circular interpolation results in a certain amount of errors from the intended track or trajectory. This study investigated the track errors associated with circular interpolation caused by input shaping for a flexible 2-axis positioning system. The following three strategies for reducing such errors were proposed: velocity reduction in circular interpolation, adjustment of the time delay between 2 axes commands, and employment of a velocity profile compensation function. Simulations were performed to discuss the pros and cons of the three proposed strategies. Experiments were also performed to validate the results. Simulation and experiments showed that the track errors due to input shaping can be sufficiently reduced by combined use of the proposed strategies.
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A Study on the Improvement of Machining Precision by Applying Input Shaping Method to Machining Center Kang-Ho Ko, Dong-Wook Lim, Seong-Wook Hong Journal of the Korean Society of Manufacturing Technology Engineers.2023; 32(4): 189. CrossRef
Input-shaping-based improvement in the machining precision of laser micromachining systems Dong-Wook Lim, Seong-Wook Hong, Seok-Jae Ha, Ji-Hun Kim, Hyun-Taek Lee The International Journal of Advanced Manufacturing Technology.2023; 125(9-10): 4415. CrossRef
Application of Input Shaping to a CNC Laser Processing Machine to Enhance Processing Precision Kang Ho Ko, Jin Uk Sim, Seong-Wook Hong Journal of the Korean Society of Manufacturing Technology Engineers.2022; 31(5): 346. CrossRef
Recently, large-scale accidents caused by minor damage from fatigue failure and impact on structures have been frequently reported. Therefore, a real-time damage monitoring system of structures is considered to be one of the most important technologies to ensure safety in various types of research. The piezoelectric sensor, which has an advantage of converting deformation of a structure into an electrical signal without using an additional power source, has been reported as one of the most suitable methods for real-time monitoring systems. This review aims to describe the structural monitoring system utilizing piezoelectric paint sensors. First, we present the concept of a piezoelectric paint sensor with the advantages of flexibility and piezoelectric performance. Then, factors affecting the performance of the piezoelectric paint sensor are introduced. Finally, an overview of piezoelectric paint sensors for structural monitoring, such as vibration detection and impact monitoring, are provided. The state-of-the-art of the application of the piezoelectric sensor is also introduced, providing feasibility in industrial fields.
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Evaluation of MWCNT/PU sponge-based triboelectric nanogenerator for harvesting mechanical energy Insik Jo, Byungchul Kim, Hyungsik Won, SunHee Kim, Kyungwho Choi, Dukhyun Choi Functional Composites and Structures.2025; 7(3): 035010. CrossRef
A theoretical and numerical FSI approach is used to predict the mass flow in a Coriolis flow meter. By comparing with the experimental results according to the relationship between mass flow and the time phase difference at the inlet and outlet of the tubes, the authors could determine the reliability of the present results from a theoretical and numerical approach in this paper. The mass flow has a linear relationship with the time phase difference, which is a unique parameter to measure true mass flow; therefore, for more precise measurement, it should be long enough to detect the signal within the given time resolution afforded by the detecting system and control system. Compact size and manufacturability, which are the important factors that decide the product competitiveness, should also be considered. In this paper, inversed triangle shaped and conventional U shaped Coriolis flow meters are designed, their time phase difference performances are predicted, and the results from experiments are well matched with the predicted results from the above-mentioned analysis.
The ultrasonic metal welding technique has been widely used because of the need to weld different materials for meeting high quality performance requirements. The key part in this type of welding is the horn, which plays an important role in the weld quality. Longitudinal vibration has so far been the most popular vibration mode for ultrasonic horns, but the longitudinal mode coupled with torsional mode is gaining a lot of attention these days owing to its better performance compared to the pure longitudinal mode. Although there are many studies on the performance of these two mode horns, comparative studies based on the performance of these two modes, particularly in ultrasonic metal welding, are very rare. This study focuses on the welding performance comparison of these two horns with 20 kHz resonant frequency. Experimental results show that the performance of the longitudinal-torsional horn is better than that of the longitudinal horn in terms of welding strength.
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Trade-off between dynamic recrystallization and material ejection during ultrasonic welding of cylindrical cell current collector plate and positive terminal Mounarik Mondal, Savyasachi Nellikode, Seong-Beom Park, Jun Mitsuyuki, Soomin Lee, Do-Hyeong Kim, Yeong-Do Park The International Journal of Advanced Manufacturing Technology.2025; 137(11-12): 5837. CrossRef
The application of ultrasound in Joining: Principles, processes and properties Zongkai Fan, Keran Bai, Chao Chen Journal of Manufacturing Processes.2023; 101: 269. CrossRef
In an environment where ultra-high-precision equipment is used, vibration inevitably occurs due to various factors. These vibrations generate fatal effects, such as defect generation and reduced production yield, on ultra-high-precision production equipment. Among the multiple methods for solving vibration problems, a Tuned Mass Damper (TMD) is a useful technique that reduces vibration without changing the existing structure by attaching a passive dynamic system consisting of additional mass, spring, and damper. However, it is difficult to realize fine-tuning of the system parameters for optimal performance because the passive elements have structural limitations. An active TMD, which has a form wherein sensors, actuators, and a control device are added to the passive TMD structure, was introduced. It has higher performance than passive TMD because dynamic characteristics can be induced to stable and highly damped by a well-designed control algorithm realized by software in the control device. In this study, an active TMD was developed utilizing passive TMD with a voice coil actuator and attached to the center of both end fixed beam that assumed a single-degree-of-freedom structure. A dual-loop control algorithm using a non-minimum phase system was designed for a high-damped response while retaining stability. The modal test was performed for experimental evaluation and excellent performance of active TMD was verified.
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Investigation on Vibration Reduction of Automotive Seat Using Dynamic Dampers Based Design of Experiment Soul Kim, Jaehyeon Nam, Dongshin Ko Transaction of the Korean Society of Automotive Engineers.2023; 31(12): 1045. CrossRef
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