• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.3
• /
• pp.231-239
• /
• 2004

A new scheme to estimate the moment of inertia in the motor drive system in very low speed is proposed in this paper. The simple estimation scheme, which is usually used in most servo system for low speed operation, is sensitive to the variation of the machine parameter, especially the moment of inertia. To estimate the motor inertia value, Reduced-Order Extended Luenberger Observer (ROELO) is applied. The effectiveness of the proposed inertia identification method using the RORLO is verified by simulation and experiment.

• Journal of Advanced Marine Engineering and Technology
• /
• v.21 no.5
• /
• pp.503-511
• /
• 1997

In 3 phase induction motor control system, the speed control using the load torque observer becomes robust against disturbances by means of a feed-forward control of the estimated load torque component. In case of variation of inertia moment, the estimated load torque has error because the observer uses the nominal inertia to estimate the load torque. And so, it is difficult to obtain good speed control characteristics. This paper has two study target strategy. First, we executes feed-forward control with the load torque observer when motor inertia has nominal value and compare it with conventional PI con¬trol. The second strategy estimates inertia moment error using the load torque observer when inertia moment change. The proposed two strategy is confirmed through the computer simulations and the experimental implementations by TMS320C31 microprocessor.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.2
• /
• pp.224-234
• /
• 1997

It was demonstrated earlier that for laminar, isothermal flow of the lubricant in long journal bearings, inertia has negligible effect on the load carrying capacity and influences only the stability characteristics of the bearing. The question in the present paper is: 'will these conclusions of the isothermal theory remain valid in the presence of significant dissipation, or will lubricant inertia and dissipation interact non-linearly to bring about qualitative changes in bearing performance\ulcorner' The results obtained here assert that the effect of lubricant inertia on load carrying capacity remains negligible, irrespective of the rate of dissipation. The stability of the bearing is, however, affected by lubricant inertia. These results, although obtained here for long bearings with Sommerfeld and Gumbel boundary conditions, are believed to be applicable to practical bearing operations and affirm that bearing load may be calculated from classical, i. e., non-inertial theory.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.15 no.6
• /
• pp.114-119
• /
• 2007

Because the small trailers do not have the main brake system, it is difficult to gain the effective braking performance of the trailers while driving them. Especially it is very hard to brake them on the slope road condition. So we have technically developed Inertia Braking System for the military trailers which have not main braking system. Inertia Braking System is designed to be activated by the inertia force of trailer. It consists of the brake rod, damping cylinder, hand brake lever and brake cables. We have tested the trailer's braking performance. As a result, we have showed that the trailer's braking performance of the trailer equipped with Inertia Braking System, the road driving performance and the braking safety capability are improved dramatically. And we hope that it is rare to happen the accident while driving.

• Journal of KSNVE
• /
• v.6 no.3
• /
• pp.287-296
• /
• 1996

A virtual work form of flexible multibody dynamic formulation with rotary inertia has been derived. For the analysis of large flexible multibody systems, deformation modal coordinates have been employed to represent coupled motion between gross and vibrational motion. For the efficient evaluation of the entries in the mass matrix, a flexible body has been treated as a collection of mass points. The rotary inertia was generated from the consistent mass matrix in a finite element model. Deformation mode shapes were obtained from finite element analysis. Bending and twisting vibration analyses of a cantilever have been carried out to see rotary inertia effects. A space flexible robot simulation has been also carried out to show effectiveness of the proposed formulation. This formulation is effective to the model that consists of beam, plate, or shell element that contains rotational degree of freedom at the nodal point. It is also effective to the flexible body model to which a large lumped rotary inertia is attached.

• Journal of KSNVE
• /
• v.8 no.2
• /
• pp.353-360
• /
• 1998

In this paper, a modeling method for the bending vibration analysis of rotating Timoshenko beams with concentrated mass and mass moment of inertia is presented. The shear and rotary inertia effects become critical for the accurate estimation of the natural frequencies and mode shapes as the slenderness ratio decreases. The natural frequencies obtained by using the Timoshenko beam theory are lower than those by using the Euler beam theory. The critical angular speed, which does not exist only with the concentrated mass, exists with the concentrated mass moment of inertia.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.155.4-155
• /
• 2001

This paper deals with the inertia property-based redundancy resolution in posture control of a mobile manipulator. As a measure for the redundancy resolution of a mobile manipulator, an effective inertia at the end effector in the operational space is proposed and investigated. The reduced effective inertia has a significant effect on reducing the impulse force in collision with environment. To find a posture satisfying both the reduced inertia and joint limit constraints, we propose a combined potential function method that can deal with multiple constraints. The proposed reduced inertia property algorithm is integrated into a damping controller to reduce the impulse force at collision and to regulate the contact force in mobile manipulation ...

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.1028-1032
• /
• 1996

Stabilization performance of a sight stabilization system can be improved by proper selection of control algorithm and mechanism. In that aspect, in this paper, effects of an inertia balancer are studied. Parameters of the inertia balancer were obtained from the governing equation by assuming there is no external force and friction. Simulation and experimental results show that the inertia balancer contributes significantly to the stabilization of the line of sight(LOS). In particular, it was found that the inertia balancer is more effective as frequency of the disturbance increases.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.542-545
• /
• 2005

This paper proposes an algorithm for the moment of inertia estimation. The algorithm finds the moment of inertia observing the position error signal, which contains an error information of moment of inertia, generated by speed observer. Moreover, the proposed algorithm is easily realized in the observer -based speed detection method. The experimental results are also presented to confirm the performance of moment of inertia estimation method. The results show that the moment of inertia converges to the actual value with the proposed method.

• Structural Engineering and Mechanics
• /
• v.55 no.4
• /
• pp.801-813
• /
• 2015

Flexural stiffness of bridge spans has become even more important parameter since Eurocode 1 introduced for railway bridges the serviceability limit state of resonance. For simply supported bridge spans it relies, in general, on accurate assessment of span moment of inertia that governs span flexural stiffness. The paper presents three methods of estimation of the equivalent moment of inertia for such spans: experimental, analytical and numerical. Test loading of the twin truss bridge spans and test results are presented. Recorded displacements and the method of least squares are used to find an "experimental" moment of inertia. Then it is computed according to the analytical method that accounts for joint action of truss girders and composite deck as well as limited span shear stiffness provided by diagonal bracing. Finally a 3D model of finite element method is created to assess the moment of inertia. Discussion of results is given. The comparative analysis proves efficiency of the analytical method.