• Journal of Ocean Engineering and Technology
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• v.11 no.1
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• pp.95-105
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• 1997

This paper presents a Inertial Measuring Unit(IMU) for motion measurement of an AUV. The IMU is composed of three parts: inertial sensors with three servo accelerometers and three rate gyros, an analog/digital interface board, and a signal processing board with TMS320C31 DSP processor. The IMU is a class of strap-down inwetial navigation system does not applicable directly to the navigation system in consequence of the AUV and integrated sensors for an integrated navigation system of the AUV. Fast calculstion of direction cosine matrix for the coordinate transformation body to reference is obtained through the DSP processor. A switching algotrithm is used to lessen the low frequency drift effect of the gyros in the vertical plane with use of low pass filtering of the signal of the accelerometers.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.1
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• pp.96-106
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• 2020

This study designed four types with a different halter-neck shoulder straps of an athleisure brassiere for women in their 20-40s as well as analyzed the shoulder strap pressure, shoulder strap position, subjective sensation, and design preference when wearing them. The design basis was to reduce the pressure at the back of the neck area, to allow the shoulder strap to pass down the neck as far as possible, and to send the anatomically sensitive side neck out as far as possible. As a result, H, which had the best subjective sensation and design preference, had the shoulder strap positioned more towards the shoulder point; in addition, the back of the neck did not pass. It was also found that the shoulder strap pressure near the neck was small. However, E, with the lowest subjective sensation, had the highest shoulder strap pressure and was placed up the neck. This confirmed that the position and pressure of the shoulder strap are variable when influencing the subjective sensation.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.1
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• pp.1-9
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• 2017

This paper proposes to improve the performance of a strap down inertial navigation system using a foot-mounted low-cost inertial measurement unit/magnetometer by configuring an attitude and heading reference system. To track position accurately and for attitude estimations, considering different dynamic constraints, magnetic measurement and a zero velocity update technique is used. A conventional strap down method based on integrating angular rate to determine attitude will inevitably induce long-term drift, while magnetometers are subject to short-term orientation errors. To eliminate this accumulative error, and thus, use the navigation system for a long-duration mission, a hybrid configuration by integrating a miniature micro electromechanical system (MEMS)-based attitude and heading detector with the conventional navigation system is proposed in this paper. The attitude and heading detector is composed of three-axis MEMS accelerometers and three-axis MEMS magnetometers. With an absolute algorithm based on gravity and Earth's magnetic field, rather than an integral algorithm, the attitude detector can obtain an absolute attitude and heading estimation without drift errors, so it can be used to adjust the attitude and orientation of the strap down system. Finally, we verify (by both formula analysis and from test results) that the accumulative errors are effectively eliminated via this hybrid scheme.

• Journal of Ocean Engineering and Technology
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• v.11 no.1
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• pp.96-96
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• 1997

This paper presents a Inertial Measuring Unit(IMU) for motion measurement of an AUV. The IMU is composed of three parts: inertial sensors with three servo accelerometers and three rate gyros, an analog/digital interface board, and a signal processing board with TMS320C31 DSP processor. The IMU is a class of strap-down inwetial navigation system does not applicable directly to the navigation system in consequence of the AUV and integrated sensors for an integrated navigation system of the AUV. Fast calculstion of direction cosine matrix for the coordinate transformation body to reference is obtained through the DSP processor. A switching algotrithm is used to lessen the low frequency drift effect of the gyros in the vertical plane with use of low pass filtering of the signal of the accelerometers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.1000-1003
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• 2014

The primary purpose of this study is to observe the dynamic behavior within a vehicle on chassis dynamometer throughout cleat impact testing with two different constraining setups (Tie-down strap and one point fixation). Throughout this empirical experiment, no outstanding dynamic behavior characteristics are observed between two setups and thus, the performance of the one point fixation device is validated. Neither the interior noise nor acceleration at driver seat rail and knuckle is heavily influenced by two different constraining methods. However, one point fixation is far more advantageous considering its shorter set up time and its capability of measuring traction force with its built in force sensor.

• International Journal of Control, Automation, and Systems
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• v.4 no.5
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• pp.615-623
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• 2006

The gyroscope free strap-down INS is composed only of accelerometers. Any gyroscope free INS navigation error is deeply affected by the accuracy of the sensor bias, scale factor, orientation and location error. However these parameters can be found by calibration. There is an important research issue about a multi-position calibration method in this paper. It provides a novel method to find the error parameters for the six-accelerometer INS. A superior simulation is shown that the multi-position calibration can find the specifications of a six-accelerometer INS in laboratory. From these parameters the six-accelerometer INS could apply in realistic navigation.

• International Journal of Control, Automation, and Systems
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• v.4 no.3
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• pp.351-358
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• 2006

The proposed inertial measurement unit (IMU) is composed of accelerometers only. It can determine a vehicle's position and attitude, which is the Gyro-free INS. The Gyro-free INS error is deeply affected by the sensor bias, scale factor and misalignment. However, these parameters can be obtained in the laboratory. After these misalignments are corrected, the Gyro-free strap-down INS could be more accurate. This paper presents a compensator design for the strap-down six-accelerometer INS to correct misalignment. A calibration experiment is taken to get the error parameters. A simulation results show that it will decrease the INS error to enhance the performance after compensation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.11
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• pp.911-920
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• 2018

In this study, we performed a study to track the angle between the guided weapon and the target by using the strap-down image seeker, and constructed a test bed that can simulate it visually. This paper describes a method to maintain high-performance feature distribution in the implementation of sparse feature tracking algorithm such as Lucas Kanade's optical flow algorithm for target tracking using image information. We have extended the feature tracking problem to the concept of feature management. To realize this, we constructed visual environment using Unity3D engine and developed image processing simulation using OpenCV. For the co-simulation, dynamic system modeling was performed with Matlab Simulink, the visual environment using Unity3D was constructed, and computer vision work using OpenCV was performed.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.295-297
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• 1986

In this study, the strap down INS on an earth satellite launch vehicle is simulated with different computing cycles between processing the IMU signals and the navigation computation. At the time of separation of booster, error are discussed. The acceptable computing cycles can be determined by simulation.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.1
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• pp.21-29
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• 2003

The Strap Down Inertial Measurement Unit(SDIMU) is recently used for the sensor package of the modern underwater vehicles such as torpedoes and unmanned underwater-vehicles. For using SDIMU, an initial alignment must be carried out before the fire or navigation stage. The general initial alignment methods require that a mother vehicle Is a stationary condition or the Inertial Navigation System(INS) of vehicle is received the specific of data navigation from the mother vehicle. But an underwater vehicle dropped from aircraft is hard to satisfy above both necessary conditions of the general initial alignment. So, we suggest a new strap down initial alignment method of an underwater vehicle dropped from aircraft without using any aided sensors. The highlight point of this method is that a period of initial alignment is not before the fire but during running stage to fix alignment error. And we verify it by analyzing various data of S/W simulations, Hardware In the Loop Simulation(HILS) tests and sea trials.