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.

This study investigated the natural frequency of a self-excited vibrating workpiece and cutting tool using a hammer impact test to acquire vibration data. Time-domain cutting vibration data were converted to the frequency domain using FFT. The workpiece signal exhibited a high amplitude, peaking at 392 Hz, while the cutting tool signal presented a peak at 930 Hz. Stability Lobe Diagrams were constructed to assess dynamic stability. Cutting experiments revealed an obvious relationship between spindle speed and signal amplitude, with higher speeds leading to larger amplitudes. Frequency analysis revealed a peak near the cutting tool's 900 Hz natural frequency. Smoother surface finishes were observed at 0.15 mm cutting depth, while 0.2 mm resulted in a wavy surface, indicating chatter. To investigate chatter frequency and reduce noise, a multiple-denoising method combined Bior 3.7 and DB10 wavelets to reduce amplitude and improve signal representation, especially for non-smooth features. The proposed method aimed to reduce the 900 Hz cutting tool’s natural frequency. Results showed a clear chatter frequency at 450-480 Hz for 0.2 mm depth cuts at spindle speeds of 500, 1,000, and 1,400 rpm. The proposed method exhibited high efficiency, achieving the higher signal-to-noise ratio and lower mean-square error than Bior 3.7 and DB10 wavelet denoising techniques.

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.

This study proposed a method for simultaneously reducing mass imbalance and vibration in gimbal systems utilizing a tuned mass damper (TMD) as a balancing weight. Finite element analysis (FEA) and experiments were used for testing the method. Mass imbalance in gimbal systems generally causes external disturbance torque. To reduce this, a balancing weight can be used. However, weight increase due to balancing weight causes resonance in the gimbal system, which generates bias error in the gyroscope sensor. This study demonstrated that both mass imbalance reduction and vibration reduction effects could be achieved by utilizing a TMD as a balancing weight. FEA results showed that the mass imbalance reduction effect of the gimbal was not affected by TMD. The magnitude of vibration response at the resonance point was reduced by about 98% with TMD. When a TMD was applied, the magnitude of the vibration response at the resonance point was reduced by 98% to the same level as that of the gimbal. Bias error of the gyroscope sensor was reduced by about 95% or more. These results show that a TMD is useful for effectively reducing mass imbalance and vibration in gimbal systems while improving gyroscope sensor performance.

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.

The pneumatic vibration isolator is economical, has no risk of contamination, and attains high vibration isolation performance by lowering the natural frequency. Pressure feedback control is used to improve the response speed of the pneumatic vibration isolator and keep the internal pressure of the pneumatic actuator constant. In this paper, the vibration isolator was actively controlled by estimating the internal pressure of the pneumatic actuator with the displacement signal. A pneumatic actuator was modeled and its dynamic characteristics were identified through frequency response measurements. A pressure observer based on relative displacement was designed, and the observer control gain was adjusted with nominal model and experiments. Pressure estimation performance and active vibration suppression performance using a pressure observer were verified through experiments. The pressure of the pneumatic actuator was estimated by the observer, and measurement noise was eliminated effectively. In addition, vibration isolation performances of direct and estimated pressure feedback showed no difference, verifying the effectiveness of the pressure observer.

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.

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.

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.

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.

As interest in the quality of life has recently increased, there is a growing interest and demand for exercise equipment, such as indoor treadmills or cycles, which can be used at home. However, the use of such indoor exercise equipment has caused social problems by generating noise between floors and causing inconvenience to neighbors. In particular, treadmills that generate a lot of vibration during use cause more social problems in an assembly building, such as an apartment. The purpose of this study is to design dampers of various shapes and to develop dampers with high vibration damping effects through vibration analysis. The damper was installed at the lower end of the treadmill to reduce vibration from the product. Three types of dampers were designed by referring to the damper shape of the existing treadmill, and the vibration reduction effect of each damper shape was verified through structural analysis of the magnitude of vibration generated from the bottom surface of each damper.