• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.6
• /
• pp.148-159
• /
• 1999

A numerical method is presented for the dynamic analysis of spur gears rotating with very high angular speeds. For an efficient computation each gear is assumed to consist of a rotating rigid disk and an elastic tooth having mass, and finite element formulations are used for the equations of motion of the tooth. The geometric constraint is imposed between the rigid disk and the elastic tooth to fix them, and contact condition is imposed between the meshing teeth of the gears. At each iteration of each time step the Lagrange multiplier and contact force are revised by using the constraint error vector, and then the whole equations of motion are time integrated with the given Lagrange multiplier and contact force. For the accurate solution the velocity and acceleration constraints as well as the displacement constraint are satisfied by the monotone reductions of the constraint error vectors. Computing procedures associated with the iterative schemes are explained and numerical simulations are conducted with the spur gears.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.660-664
• /
• 2003

The optimal thickness distribution of an active damping layer is sought so that it satisfies a certain constraint on the dynamic performance of a system minimizing control efforts. To obtain a topologically optimized configuration, which includes size and shape optimization, thickness of the active damping layer is interpolated using linear functions. With the control energy as the objective function to be minimized, the state error energy is introduced as the dynamic performance criterion for the system and used lot a constraint. The optimal control gains are evaluated from LQR simultaneously as the optimization of the layer position proceeds. From numerical simulation, the topologically optimized distribution of the active damping layer shows the same dynamic performance and cost as the Idly covered counterpart, which is optimized only in terms of control gains, with less amount of the layer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.10a
• /
• pp.602-603
• /
• 2014

A gearbox can be regarded as a self-exciting dynamic system, which has a vibration source. Transmission error (TE) is considered to be an main excitation source for gear noise and vibration. The TE excitation is transmitted through the gears, shafts, bearings, and housings. Thus, an experimental approach to each mechanical parts is useful in order to understand and evaluate the dynamic behaviour of a gearbox. This study is focused on the transmission and vibration characteristics of a helical gear system in development stage. In addition, by considering the tolerance factors and resonance characteristics, the vibration response of actual dynamic system is analysed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.05a
• /
• pp.224-231
• /
• 2006

A six-degree-of-freedom dynamic model with time-varying mesh stiffness/damping and friction has been developed for the dynamic analysis of a gear driving system. This model includes a spur gear pair, bearing, friction and prime mover. Using Newton???s method, equations of motion for the gear driving system were derived. Two computer programs are developed to calculate mesh stiffness, transmission error and friction force and analyze the dynamics of the modeled system using a time integration method. The influences of mesh stiffness/damping, bearing, and friction affecting the system were investigated by performing eigenvalue analysis and time response analysis. It is found that the reduction of the maximum peak magnitude by friction is decided according to designing the positions of pitch point and maximum peak in the responses.

• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.335-340
• /
• 2001

It is important to model the mechanical structure precisely and reasonably in predicting the dynamic characteristics, controlling the vibration, and designing the structure dynamics. In the finite element modeling, the errors can be contained from the physical parameters, the approximation of the boundary conditions, and the element modeling. From the dynamic test, more precise dynamic characteristics can be obtained. Model updating using parameter modification is appropriate when the design parameter is used to analyze the input parameter like finite element method. Finite element analysis for cantilever and simply supported beams with uniform area and shape change are carried out as model updating examples. Mass and stiffness matrices are updated by comparing test and analytical modal frequencies. The result shows that the updated frequencies become closer to the test frequencies.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.9
• /
• pp.1589-1596
• /
• 2003

In this paper, we performed the improvement study for the dynamic characteristics enhancement of the motor stator coil vertical winding machine. The dynamic characteristics improvement was done by means of the optimized design and the weight reduction of the flyer configuration, modified design of the servo control system for the flyer and the former actuation, and the development of jump timing digital circuit for the reduction of former jumping error. As the results, the maximum winding speed pattern of the developed machine was attained up to 3000rpm and also reduced the jumping error. In conclusion, domestic design technology for manufacturing the motor coil vertical winding machine was established through this study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.05a
• /
• pp.103-105
• /
• 2002

Instantaneous following PWM control technique is pulsed nonlinear dynamic control method. This new control technique using analog integrator is proposed to control the duty ratio D of Cuk converter. In this control method, the duty ratio of a switch is exactly equal to or proportional to the control reference in the steady state or in a transient. Proposed control method compensates power source perturbation in one switching cycle, and the average value of the dynamic reference in one switching cycle. There is no steady state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with Cuk converter have demonstrated the robustness of the control method and verified theoretical prediction. The control method is very general and applicable to all type PWM.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.664-667
• /
• 1996

This paper presents the error parameter estimation technique for IMU(Inertial Measurement Unit) which is core sensor of INS(Inertial Navigation System) and verifies it via laboratory test. Firstly the error characteristic of gyroscope and accelerometer which is contained in IMU is examined and the error modelling is executed. The error of IMU can be divided into deterministic and random part, and the deterministic error can be divided into static and dynamic part. This paper consider the random part as constant. Secondly the error parameter estimation technique and following procedure for laboratory test is explained. Thirdly according to the test procedure the IMU test for static error is executed using 2-axis rate table and estimation result is presented with discussion about its validity.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.629-630
• /
• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.05a
• /
• pp.913-914
• /
• 2012