• 한국정밀공학회지
• /
• 제19권4호
• /
• pp.147-153
• /
• 2002

In the preceding research, the active balancing device, which is an electro-magnetic type, has been developed and active balancing method using influence coefficient method is also proposed. The stability of active balancing control is studied in this paper. A stable condition for active balancing control is derived by estimating errors of influence coefficients. A gain scheduling control using influence coefficients of the reference model is proposed when dynamic characteristic of rotor system is changed. The stability of the balancing method is verified by experiments.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 추계학술대회 논문집
• /
• pp.769-772
• /
• 1995

Most turbo machines, which operate at high speeds, such as gas turbines, jet engines, pumps, and compressors are prone to perrturbing vibrations. The best vibration control method for rotors is to eliminate destabilizing factors. Careful balancing application of "more stable" oil-lubricated bearing, such as tilting pad bearings or use of anti-swirl devices in seals, are examplse of passive vibration control methods. the use of magnetic bearing is an active control method. An obvious advantage of active control is that it provides damping (or modifies system stiffness or other parameters) only when there is a need for that, i.e., in emergency states, while not affecting the rotor normal operational conditions. Moreover, active control methods provide exact position control through on-line control. In this study, a magnetic actuator, digital contrliier using DSP, and bipolar operational power supply/amplifiers were developed to show the effectiveness of reducing robot vibration. Also the curve fitting procedure to obtain the transfer function of frequency dependent component was developed. Results presented in this dissertation will provide a well-defined technical parameters in designing magnetic damper system.er system.

• 대한기계학회논문집
• /
• 제17권12호
• /
• pp.3073-3082
• /
• 1993

A magnetically suspended robot joint is developed, which is free of dust and oil generation. Two radial bearings consisting of cone-shaped magnet cores control the rotor motion in the axial and radial directions. A linearized dynamic model is developed for active control of the magnetic bearing system. The control algorithm is constructed such that the axial displacement of the joint is controlled by radial control current to the pairs of facing radial bearings. The stability and control performance is tested through numerical simulation based on the nonlinear model. Experiments are also performed to verify the theoretical development.

• 한국정밀공학회지
• /
• 제25권3호
• /
• pp.83-92
• /
• 2008

This paper develops the theory for a fault-tolerant, permanent magnet biased, homopolar magnetic bearing. If some of the coils or power amplifiers suddenly fail, the remaining coil currents change via a novel distribution matrix such that the same magnetic forces are maintained before and after failure. Lagrange multiplier optimization with equality constraints is utilized to calculate the optimal distribution matrix that maximizes the load capacity of the failed bearing. Some numerical examples of distribution matrices are provided to illustrate the theory. Simulations show that very much the same dynamic responses (orbits or displacements) are maintained throughout failure events (up to any combination of 3 coils failed for the 6 pole magnetic bearing) while currents and fluxes change significantly. The overall load capacity of the bearing actuator is reduced as coils fail. The same magnetic forces are then preserved up to the load capacity of the failed.

• 한국소음진동공학회논문집
• /
• 제17권11호
• /
• pp.1102-1111
• /
• 2007

The theory for a fault-tolerant control of homopolar magnetic bearings is developed. New coil winding law is utilized such that control fluxes are isolated for an 8-pole homopolar magnetic bearing. Decoupling chokes are not required for the fault tolerant magnetic bearing since C-core fluxes are isolated. If some of the coils or power amplifiers suddenly fail, the remaining coil currents change via a distribution matrix such that the same magnetic forces are maintained before and after failure. Lagrange multiplier optimization with equality constraints is utilized to calculate the optimal distribution matrix that maximizes the load capacity of the failed bearing. Some numerical examples of distribution matrices are provided to illustrate the theory. Simulations show that very much the same dynamic responses (orbits or displacements) are maintained throughout failure events while currents and fluxes change significantly.

• 한국실천공학교육학회논문지
• /
• 제1권1호
• /
• pp.61-65
• /
• 2009

공학교육을 위한 실습장비가 다양하지 못함에 따라 특정 실습을 위해서 맞춤식 교육용 장비 개발이 절실한 경우가 많다. 특히 전공심층과목인 진동공학에 관련된 교육장비는 국내외 부족한 실정이다. 이에 따라 실제 현장에서 발생되는 진동현상을 구현하면서, 진동공학의 이론교육과 실습을 위한 교육용 장비들을 개발할 필요가 있다. 본 논문에서는 학부생 졸업연구작품 과제를 통해서 개발된 임계속도 측정용 회전체 교육장비, 밸런싱 머신 교육장비, 자석을 이용한 흡진기 교육장비 및 능동진동제어 교육장비를 각각 소개하고, 수업시간을 통해서 교육장비들의 활용성 및 실용성을 검증하였다. 또한 미래 교육장비의 개발 및 적용에 대한 개선안도 제안하였다.