An airborne black box should preserve the recorded data under the extreme environmental conditions such an aircraft crash. Through the recorded information from the black box, the cause of the aircraft crash can be analyzed. This requires the black box to safely protect its memory board inside from the external forces or heat generated by the aircraft crash. This paper is a case study conducted to develop the black box to satisfy the crash survival requirements of ED-112A, the standard of performance to develop the black box, and optimize its weight and size. Through the sequential design, analysis, and test process, the black box successfully demonstrated the optimized design, analysis and test subjected to crash survival requirements of ED-112A. The prototype of the black box was fabricated and tested for the verification of each analysis within the requirements of ED-112A.
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Study on the Design Method of Small Black Box for Aircraft that Satisfies Extreme Environment Requirements Dong-Hun Son, Kwang-Min Kim, Jong-Hak Lee, Gu-Hyun Ryu Transactions of the Korean Society for Noise and Vibration Engineering.2024; 34(4): 385. CrossRef
The assembly misalignment of a high maneuver precision guidance missile such as anti-air interceptor could have poor influence on the performance of the system and lead to fatal mission failure. Thus, several methods to minimize the assembly misalignment of missiles have been suggested, including assembly guiding tools and measuring devices. However, previously suggested solutions have disadvantages in versatility and cost. In this study, the low cost and universally applicable solution based on inclinometers for measuring assembly misalignment of a missile is introduced. The comparison between measurement data of the suggested system and a three-dimensional laser tracker for a missile assembly misalignment was conducted. The results show the suggested system can quantify a missile assembly misalignment with comparable precision and accuracy.
Actuators for exoskeleton robots comprise various types such as electric, hydraulic, and pneumatic and it is necessary to apply the correct actuator according to the purpose. Most exoskeleton robots mainly use electric actuators, and some special-purpose robots, such as for heavy-load transport requiring large force, use hydraulic actuators. In this paper, friction of the actuation module consisting of a harmonic drive and a brushless DC motor is measured through experiments. And the friction characteristics of the actuation module are analyzed. The harmonic drive transmission system has various advantages, but it also has hysteresis and nonlinear friction characteristics. The friction compensation control of the actuation module enables precise control of the exoskeleton robot, and improves the robot’s performance. Appropriate friction model selection and design affects friction compensation performance. In this study, static and dynamic friction models are designed and analyzed based on the friction data of the actuation module.
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Method for Radial Stiffness Measurement of Strain Wave Gear Flexspline Sangwoong Lee, Daegwon Koh, Jong-Geol Kim, Murim Kim Journal of the Korean Society for Precision Engineering.2024; 41(12): 923. CrossRef
A Recurrent Neural Network for 3D Joint Angle Estimation based on Six-axis IMUs but without a Magnetometer Chang June Lee, Woo Jae Kim, Jung Keun Lee Journal of the Korean Society for Precision Engineering.2023; 40(4): 301. CrossRef
Friction Compensation of Electric-Motor Driven Revolute Joint with Harmonic Gear Seong-Hee Cho, Young-Seog Kim, Jung-Yup Kim Journal of the Korean Society of Manufacturing Technology Engineers.2020; 29(3): 259. CrossRef
This study proposed the proper detonation delay time of a main warhead after a precursor warhead detonation in an arbitrary tandem shaped charge missile as 407 μsec. In addition, the available detonation delay time range of the main warhead was proposed to be between 396 μsec and 418 μsec. The proposed figures were based on the analysis of the target protection capability and the scattering reactor behaviors of the explosive reactive armor with dual reactive panels. By virtue of this work, the determination of main warhead detonation delay time is more effective and convenient. Finally, the tandem shaped charge missile with more effective penetration performance also could be developed in the future.
Since earth pressure changes depend on soil depth and surrounding situations, the construction of earth retaining temporary structures should be able to measure the change of the earth pressure and cope with the changes. When the underground excavation and construction of earth retaining temporary structure repeatedly occur, the excavation should be less interfered by the earth retaining structure. A PS synchronize wale measures the horizontal deflection of the structure and generates tension on the wire rope by controlling the hydraulic cylinder so that the wale is in safe range. Since the horizontal load is canceled by pre-stress bending moment, the number of struts the horizontal load is reduced making the excavation interference is small. We evaluated the horizontal deflection of the PS synchronize wale with increasing tension and verified that the deflection of the PS synchronize wale can cancel out the horizontal load in the safety range of 5 mm. This occurs through a universal testing machine experiment simulating earth pressure. We are in the process of applying the PS synchronize wale to a test bed and expect it to be safer and more efficient than existing methods.
Recently, improvement of productivity of the paper cup forming machine has being conducted by increasing manufacturing speed. However, rapid manufacturing speed imposes high load on cams and cam followers. It accelerates wear and cracking, and increases paper cup failure. In this study, a failure diagnosis algorithm was suggested using vibration data measured from cam driving parts. Among various paper cup forming processes, a test bed imitating the bottom paper attaching process was manufactured. Accelerometers were installed on the test bed to collect data. To diagnose failure from measured data, the K-NN (K-Nearest Neighbor) classifier was used. To find a decision boundary between normal and abnormal state, learning data were collected from normal and abnormal state, and normal and abnormal cams. A few representative features such as mean and variance were selected and transformed to the relevant form for the classifier. Classification experiments were performed with the developed classifier and data gathered from the test bed. According to assigned K values, a successful classification result was obtained which means appropriate failure recognition.
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A Study on 3D Printing Conditions Prediction Model of Bone Plates Using Machine Learning Song Yeon Lee, Yong Jeong Huh Journal of the Korean Society for Precision Engineering.2022; 39(4): 291. CrossRef
In recent years, the manufacture connector terminals of electronic devices require an accuracy of several microns and high productivity, thus the need to develop the ultra-high speed press technology. However, increased impulse and vibration of ultra-high speed press have reduced durability of stamping die and induced serious tool wear. To solve this problem, we investigate the changes of vibrations occurring in the die and press machine under ultra-high speed working condition by using a piezoelectric sensor. Moreover, by analyzing the design parameters such as stroke, stripper movement, and collision velocity of the die, impulse and vibration were decreased, thus improving the punch life by 50% under 2,000 SPM (stroke per minute) condition
From the past, productivity improvement has been a problem to be solved, and various methods have been continuously developed. Recently, the demand for electric vehicles has increased along with the domestic and international environmental policies. Researches on the electrode production facilities have been actively conducted to increase the productivity of secondary batteries. Dispensers required for bonding the separator of the secondary battery, the cathode material and the anode material are also increasing in demand. The dispensers that spray a certain amount of adhesive quickly contribute to productivity improvement. However, Piezo type, which is currently being developed and used widely, has a higher performance than some industry, and its more expensive. In this study, we design a dispenser with lower performance than the conventional piezo type and lower the unit price and analyze the results.
Industrial robots are widely used for part manufacturing besides simple task (welding, assembly). A parallel kinematic machine (PKM) with extending axes have been utilized in large volume machining because of their adequate stiffness and agility. Parallelism error in the PKM with an extending axis causes deterioration of dimensional accuracy of machined parts. This paper proposes a technique for compensating the parallelism error through measurement of the squareness error between the PKM with its extending axes using a laser interferometer. The four squareness errors are estimated to reduce the parallelism errors. The squareness error is calculated by measuring linearity of the extending axis and the PKM moving axis, and through the measurement of diagonal displacement error and position dependent geometric errors. Compensation of the parallelism error was done by transforming the basic coordinate system of the PKM. The parallelism error was significantly reduced from 0.735 to 0.022 mm and further verified experimentally.
Safe pre-operative traction applied and maintained to the fractured site in fracture reduction surgery is crucial. However, existing traction techniques performed by clinicians or manual traction devices are not elaborate and have no traction force information considering differences in patients’ bodies. The purpose of this study was to evaluate joint loads of fractured sites as pre-operative traction forces considering body mass index (BMI) during fracture reduction surgeries using a robotassisted device. We developed a lower-extremity dummy model to measure joint loads at hip, knee, ankle, and fractured sites. In 240 cases, four BMI types, six traction forces and two fractured sites were used. Results showed that joint load on major joints decreased as BMI increased. Additionally, joint load increased proportionally in the fractured tibia, but showed inverse tendency in the fractured femur. Control errors of up to 20% in repetitive control and approximately 30% in random control were measured, in comparison to estimated joint loads. Control error increased as traction force decreased. It is possible that applicability of robot systems to safe and precise surgical assistance can be validated. More precise traction control and real-time traction load monitoring technology will enable replacement of traction techniques in the near future.
The aim of the study is to create a method for selecting an asynchronous traction electric drive for an electric vehicle that enable the assessment of necessary technical, environmental and operational qualities. When choosing an electric motor for a traction electric drive, the methods for calculating electric machines, reducing the vibrations and electric drive theory were used. The economic and environmental characteristics of the car was analyzed and the use of a traction drive was deemed an effective solution to this problem. The analysis of advantages and disadvantages in traction electric drive were assessed and it was proved that an asynchronous frequency-controlled electric motor is well suited for a traction electric drive. This facilitates the minimization of the size and weight of the entire vehicle. To improve the reliability and service life of electric motors operating in automobiles with high rotational frequencies, a proposal to evaluate the quality of traction electric motors by the level of vibration in the frequency range of 5-10,000 Hz was made. For this study, three classes of vibration norms are offered and the means to achieve them are examined and the recommendations not to exceed them in electric and hybrid vehicles were determined.
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Requirements for vibroacoustic methods of the quality assessment of vehicles traction electric motors Vasiliy Migal, Shchasiana Arhun, Andrii Hnatov, Olha Ulianets, Igor Shevchenko Noise & Vibration Worldwide.2024; 55(4-5): 210. CrossRef
Analysis of the preferential effects of the use of asynchronous electric motors in the industrial sector G. S. Armashova-Telnik, T. A. Bobovich Proceedings of the Voronezh State University of Engineering Technologies.2022; 84(2): 329. CrossRef
Estimation of Excitation Current of a Synchronous Machine Using Machine Learning Methods Matko Glučina, Nikola Anđelić, Ivan Lorencin, Zlatan Car Computers.2022; 12(1): 1. CrossRef
Design optimization of vehicle asynchronous motors based on fractional harmonic response analysis Ao Lei, Chuan-Xue Song, Yu-Long Lei, Yao Fu Mechanical Sciences.2021; 12(1): 689. CrossRef
Reducing the vibration of bearing units of electric vehicle asynchronous traction motors Vasiliy Migal, Anatoliy Lebedev, Mykhailo Shuliak, Evgeniy Kalinin, Shchasiana Arhun, Vladimir Korohodskyi Journal of Vibration and Control.2021; 27(9-10): 1123. CrossRef
Choice of Parameters for the Electrodrive Diagnostic System of Hybrid Vehicle Traction S. Arhun, Yu. Borodenko, A. Hnatov, A. Popova, H. Hnatova, N. Kunicina, A. Ziravecka, A. Zabasta, L. Ribickis Latvian Journal of Physics and Technical Sciences.2020; 57(4): 3. CrossRef
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