• Journal of the Korea Society of Computer and Information
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• v.21 no.3
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• pp.83-89
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• 2016

Internet of Things (IoT) is widely used for biomechanics in sports activities and AHRS(Attitude and Heading Reference System) is a more cost effective solution than conventional high-grade IMUs (Inertial Measurement Units) that only integrate gyroscopes. In this paper, we attach the AHRS to the snowboard to measure the motion data like Air To Fakie, Caballerial and Free Style. In order to reduce the measurement error, we have adopted the sensors equipped with Kalman filtering and also used Euler angle to quaternion conversion to reduce the Gimbal-lock effect. We have tested and evaluated the accuracy and execution time of the pattern recognition algorithms like PCA, ICA, LDA, SVM to show the recognition possibility of it on the basic motions of Snowboarding from the 9-axis trajectory information which is gathered from AHRS sensor. With the result, PCA, ICA have low accuracy, but SVM have good accuracy to use for recognition of basic motions of Snowboarding.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3800-3804
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• 2013

In this study, molecular dynamics simulations of SPC/E (extended simple point charge) model have been carried out in the canonical NVT ensemble over the range of temperatures 300 to 550 K with and without Ewald summation. The quaternion method was used for the rotational motion of the rigid water molecule. Radial distribution functions $g_{OO}(r)$, $g_{OH}(r)$, and $g_{HH}(r)$ and self-diffusion coefficients D for SPC/E water were determined at 300-550 K and compared to experimental data. The temperature dependence on the structural and diffusion properties of SPC/E water was discussed.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.62.3-62
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• 2001

The predictive control is one of the nonlinear three-axis rotation methods. The desired trace of a satellite is pre-determined, and the control inputs are designed so that the satellite follows the ´predictive´ trace. The predictive control has been adapted to the research for the three-axis attitude control. In that case, the control variables are the quaternion represented the angular rates and attitude angles of the body about the three-axes. The objective of this paper is to propose to design a predictive controller for the three-axis attitude control under external disturbances. In order to do that, this paper proposes how to construct a predictive control law including disturbances and to discern them. The basic algorithm of the existent predictive control is partially modified, and the presumption and modeling of disturbances are performed ...

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.115-118
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• 1995

This paper present an attitude control using quaternions as feedback attitude errors. The Euler's eigenaxis rotation provides the shortest angular path between two attitudes. This eigenaxis rotation can be achieved by using quaternions since quaternions are related with the eigenaxis. The suggested controller uses error quaternions and body angular rates and generates a decoupling control torque that counteracts the natural gyroscopic coupling torque. The momentum dumping strategy using the earth magnetic field is also applied in this paper to unload the angular momentum of the reaction wheels used in the attitude control.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.5
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• pp.674-679
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• 1998

In this paper, a new coarse alignment algorithm is proposed for roughly determining the initial attitude of the vehicle. The algorithm, referred as two-step coarse alignment algorithm, computes roll and pitch angle of the vehicle using accelerometer outputs, and then determines yaw angle with gyro outputs. With the geometric relation between sensor outputs and attitude angles, the algorithm error is analytically derived and compared with the previous coarse alignment algorithm that computes a transformation matrix using accelerometer md gyro outputs simultaneously. The simulation is also performed by varying the sensor errors. The results show that the proposed two-step coarse alignment algorithm has better performance for east tilt angle.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.3
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• pp.242-247
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• 1996

In this paper, an optimal coning compensation algorithm for strapdown system is proposed by minimizing the coning error. The proposed algorithm is derived as a generalized form in that it contains the class of the existing coning algorithms and allows the design of optimal algorithm for various combinations of gyro samples. It is shown the magnitude of resulting algorithm errors depends mainly on the total number of gyro samples including present and previous gyro samples. Based on the results, the proposed algorithm enables the algorithm designers to develop the effective coning compensation algorithm according to their attitude computation specifications with ease. In addition, the multirate method which can efficiently implement the algorithm is presented.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.3
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• pp.291-297
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• 2000

This paper presents an attitude determination algorithm for the local level strapdown inertial navigation where the body the earth and the transport rate can be calculated separately using a DCM computation scheme, Also presented is a velocity determination algorithm taking into account the attitude variation caused by he change of the navigation frame. The proposed algorithm are implemented using three samples of the velocity and the angle within the integration interval.

• International Journal of Control, Automation, and Systems
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• v.1 no.4
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• pp.520-526
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• 2003

In the case of a strapdown inertial navigation system (SDINS) with sizeable attitude errors, the uncertainty caused by linearization of the system degrades the performance of the filter. In this paper, a robust filter and various error models for the uncertainty are presented. The analytical characteristics of the proposed filter are also investigated. The results show that the filter does not require the statistical property of the system disturbance and that the region of the estimation error depends on a freedom parameter in the worst case. Then, the uncertainty of the SDINS is derived. Depending on the choice of the reference frame and the attitude error state, several error models are presented. Finally, various in-flight alignment methods are proposed by combining the robust filter with the error models. Simulation results demonstrate that the proposed filter effectively improves the performance.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.4
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• pp.369-373
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• 2001

This paper is concerned with a transfer alignment of SDINS under ship motions. To reduce alignment errors induced by the ship body flexure, an error compensation method is suggested based on velocity and DCM partial matching, and by interpreting the simulation results and comparing with the conventional velocity and quaternion partial matching, it is shown that the proposed method is effective enough to improve the azimuth alignment performance.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.4-4
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• 2000

In this paper, the backstepping control method that is useful for cascade systems is applied to the slew maneuver of the spacecraft. The quaternion is used for representing the attitude of the spacecraft, because the reference trajectory of angular velocity has simple mathematical form. The conventional backstepping control has severa] problems such as slow convergence, trivial cancelling of nonlinear terms, and excessive control input. To overcome these problems, the modified backstepping control method which is redesign of Lyapunov function is proposed. To design a tracking function for angular velocity, it is necessary to estimate the process of maximum angular velocity, and therefore the estimation procedure using Bellman-Gronwall inequality is developed. To verify the effectiveness of the proposed control law, numerical simulation is performed and the results are compared with the exiting control scheme.