• Journal of Astronomy and Space Sciences
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• v.27 no.4
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• pp.353-357
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• 2010

In general, the information of inertia properties is required to control a spacecraft. The inertia properties are changed by some activities such as consumption of propellant, deployment of solar panel, sloshing, etc. Extensive estimation methods have been investigated to obtain the precise inertia properties. The gyro-based attitude data including noise and bias needs to be compensated for improvement of attitude control accuracy. A modified estimation method based on the law of conservation of angular momentum is suggested to avoid inconvenience like filtering process for noise-effect compensation. The conventional method is modified and beforehand estimated moment of inertia is applied to improve estimation efficiency of product of inertia. The performance of the suggested method has been verified for the case of STSAT-3, Korea Science Technology Satellite.

• Structural Engineering and Mechanics
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• v.35 no.1
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• pp.53-65
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• 2010

The rigid body inertia properties of a structure including the mass, the center of gravity location, the mass moments and principal axes of inertia are required for structural dynamic analysis, modeling of mechanical systems, design of mechanisms and optimization. The analytical approaches such as solid or finite element modeling can not be used efficiently for estimating the rigid body inertia properties of complex structures. Several experimental approaches have been developed to determine the rigid body inertia properties of a structure via Frequency Response Functions (FRFs). In the present work two experimental methods are used to estimate the rigid body inertia properties of a frame. The first approach consists of using the amount of mass as input to estimate the other inertia properties of frame. In the second approach, the property of orthogonality of modes is used to derive the inertia properties of a frame. The accuracy of the estimated parameters is evaluated through the comparison of the experimental results with those of the theoretical Solid Work model of frame. Moreover, a thorough discussion about the effect of accuracy of measured FRFs on the estimation of inertia properties is presented.

• Journal of Drive and Control
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• v.14 no.3
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• pp.40-49
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• 2017

This study presents an online estimation of an excavator's rotational inertia by using recursive least square with forgetting. It is difficult to measure rotational inertia in real systems. Against this background, online estimation of rotational inertia is essential for improving safety and automation of construction equipment such as excavators because changes in inertial parameter impact dynamic characteristics. Regarding an excavator, rotational inertia for swing motion may change significantly according to working posture and digging conditions. Hence, rotational inertia estimation by predicting swing motion is critical for enhancing working safety and automation. Swing velocity and damping coefficient were used for rotational inertia estimation in this study. Updating rules are proposed for enhancing convergence performance by using the damping coefficient and forgetting factors. The proposed estimation algorithm uses three forgetting factors to estimate time-varying rotational inertia, damping coefficient, and torque with different variation rates. Rotational inertia in a typical working scenario was considered for reasonable performance evaluation. Three simulations were conducted by considering several digging conditions. Presented estimation results reveal the proposed estimation scheme is effective for estimating varying rotational inertia of the excavator.

• Asia pacific journal of information systems
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• v.26 no.2
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• pp.268-289
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• 2016

While most of studies have paid attention to the initial adoption of a specific application, research on applications has not focused on an individual's update decision process. This study draws upon both dual information processing and status quo bias perspectives as a comprehensive theoretical lens to explain why individuals do not update their applications. This study assumes that individuals' inertia could be the main reason for their reluctance to update the applications. Based on a survey of 186 smartphone users, this study demonstrated that both habit as an affective trigger of system 1 thinking and sunk cost as a cognitive trigger of system 2 thinking promoted the two types of inertia (i.e., affective and cognitive based inertia) in individuals, which have a negative effect on their willingness to update their applications. By grounding the research model in a theoretical view, such as dual information processing and status quo bias, this study provides a unique theoretical lens from which to view individuals' behaviors, thereby gaining a better understanding of their decision not to update to the current version of applications. This study also investigates the moderating effect of the types of applications on the relationships between affective/cognitive-based inertia and willingness to update. Results show that both habit and sunk cost decrease the willingness to update because they increase both affective and cognitive-based inertia. This study also found that the effects of affective/cognitive based inertia differed depending on the type of applications.

• Journal of Engineering Education Research
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• v.23 no.3
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• pp.32-40
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• 2020

A new moment of inertia experiment apparatus different from the existing one has been developed, which does not require deformation of a sample in order to fix it to the apparatus. This new experiment apparatus was able to experiment with constant-shaped objects that did not deform the samples, so that it enabled them for conducting an experiment which is close to an ideal rigid model dealt in the general physics course. The new experimental apparatus was easy and accurate in measuring the physical quantity by using the experimental principle of physical pendulum. In the results of the measurement of the moments of inertia of the six samples, all measurements were made to be accurate enough to measure with very small errors within 1%. In addition, it has been found to be useful as an experiment apparatus to understand the concept of the moment of inertia and to prove the formula for moment of inertia. Therefore, if the new moment of inertia experiment apparatus developed in this study is used in students' experiments, it is expected that students will be able to greatly increase their understanding of the concept of moment of inertia.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.4
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• pp.287-294
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• 2004

Dynamic Load/unload (L/UL) mechanism is an alternative to the contact start stop (CSS) technology which eliminates striction and wear failure modes associated with CSS. Inertia latch mechanism becomes important for mobile disk drives because of non operating shock performance. Various types of latch designs have been introduced in hard disk drives to limit a rotary actuator from sudden uncontrolled motion. In this paper, a single spring inertia latch is introduced for a small form optical disk drive, which uses a rotary actuator for moving an optical pick-up. A new small inertia latch with sin91e spring is designed to ensure both feasible and small size. The shock performance of the new inertia latch is experimentally verified.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.311-316
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• 2007

This paper proposes the algorithm which estimates moment of the inertia and friction coefficient of friction for high performance speed control of electric motor. The proposed algorithm finds the moment of inertia and friction coefficient of friction by observing the speed error signal generated by the speed observer and using Recursive Least-Mean-Square method(RLS). By feedbacking the estimated inertia and estimated coefficient of friction to speed controller and full order speed observer, then the errors of the inertia and coefficient of friction and speed due to the inaccurate initial value are decreased. Inertia and coefficient of friction converge to the actual value within several times of speed changing. Simulation and actual experiment results are given to demonstrate the effectiveness of the proposed parameter estimator.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1196-1201
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• 2014

This paper presents an exploration on the effect of wind turbine contribution to the frequency control of individual systems that can be used for efficient power production in India. The research includes the study of Permanent Magnet Synchronous Generator (PMSG), in wind farms. The WTs are tested for inertia and for droop responses with intelligent fuzzy logic controllers (FLC) that choose Double Input Single Output (DISO) strategy that automatically sets gain constants, as well as combined responses for the WTs. Quantitative analyses are presented for the WTs for benefits and drawbacks including appropriate selection parameters. The analysis includes inertia, droop and combined inertia, droop schemes. The reconnaissance also incorporates inertia with FLC, droop with FLC, inertia and droop with FLC schemes for detailed study of WTs, so as to forecast and achieve proper frequency control. Moreover, the analysis provides the best suited method for frequency control in PMSG.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.102-107
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• 1986

This paper presents a new idea to obtain moment of inertia values of an arbitrary shape body by applying inverse modal transformation technique. A multiaxes inertia pendulum apparatus was designed to measure 6 rigid body modes of a test body. A software was developed to calculate inertia properties as well as the location of center of gravity and total mass of the test body from the measured modal data. The developed method was applied to a simple body of which the inertia properties are known then the obtained values were compared with the known values.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.3
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• pp.55-60
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• 2003

In the controller design of position or velocity control system, the flexibility of the mechanical system is always the limiting factor to the higher performance. Most mechanical systems coupled with rotary shaft are 2-Inertia systems which are consist of motor and load inertia. These inertias make a torsion In rotary shaft and cause torsional vibration. To suppress vibration, various control strategies have been proposed mainly for controlling 2-inertia system. In this paper, a speed controller design for a 2-inertia system composed of voltage controlled DC motor and load inertia is made by using CDM(coefficient diagram method). First, the 2-inertia system model is derived. Then the CDM is used to design the proper controller. A validity of this approach is confirmed by simulation and experimental results.