• 한국소음진동공학회논문집
• /
• 제26권7호
• /
• pp.875-880
• /
• 2016

A new hybrid permanent magnet biased magnetic levitation actuator (maglev) is developed. This new maglev actuator is composed of two C-core electromagnetic cores separated with two permanent magnets. Compared to the conventional hybrid maglev actuators, the new actuator has unique flux paths such that bias flux paths are separated with control flux paths. The control flux paths have minimum reluctances only developed by air gaps, so the currents to produce control fluxes can be minimized. The gravity load can be compensated with the permanent magnet bias fluxes developed at off-centered air gap positions while external disturbances are controlled with control fluxes by currents. The consumed power to operate this levitation system can be minimized. 1-D magnetic circuit model is developed for this model such that the flux densities and magnetic forces are extensively analyzed. 3-D finite element model is also developed to analyze the performances of the maglev actuator.

• 대한기계학회논문집A
• /
• 제24권3호
• /
• pp.691-700
• /
• 2000

This paper presents a novel type of a semiactive damper featuring an electro-rheological(ER) fluid. Unlike conventional cylindrical ER damper, the proposed one has controllable orifices by the intensity of electric fields (We call it orifice type). The dynamic model of the orifice type ER damper is formulated by incorporating field-dependent Bingham properties of an arabic gum-based ER fluid. Design parameters such as electrode gap are subsequently determined on the basis of the dynamic model. After manufacturing the orifice type ER damper, field-dependent damping forces and damping force controllability are empirically evaluated. In the evaluation procedure, conventional cylindrical ER damper is adopted and its performance characteristics are compared with those of the orifice type ER damper. In addition, the proposed one is installed with a full-car model and its vibration control performance associated with a skyhook controller is investigated.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1998년도 춘계학술대회 논문집
• /
• pp.148-153
• /
• 1998

In order to control thermal deformation of machine origin of machine tools due to internal and external heat sources, the real-time compensation system has been developed. First, GMDH models were constructed to estimate thermal deformation of machine origin for a vertical machining center through the measurement of deformation data and temperature data of specific points on the machine tool. Thermocouples and gap sensors are used respectively for measurement. These models are nonlinear equations with high-order polynomials and implemented in a multilayered perceptron type network structure. Secondly, work origin shift method were developed by implementing digital I/O interface board between CNC controller and IBM-PC. The work origin shift method is to shift the work origin by the compensation amounts which is calculated by pre-established GMDH model. From the experimental result, thermal deformation of machine origin was reduced to below $\pm$5${\mu}{\textrm}{m}$.

• 한국철도학회논문집
• /
• 제9권4호
• /
• pp.455-460
• /
• 2006

본 논문에서는 자속 궤환을 포함하는 자기부상 시스템의 open-loop 특성에 대해서 다룬다. 훌륭한 외란 억제 특성을 포함하고 파라메타 변동에 대해서 둔감한 제어기를 설계하기 위해서 자속 궤환을 이용하는 것이 효과적일 수 있다. 적절한 센서에 의해서 측정 가능한 자속은 전류와 공극의 시간 변화에 대해서 선형적인 관계를 가지고 있으며, 자속의 궤한은 자기 부상시스템이 본질적으로 갖고 있는 전기적 엑츄에이터와 기계적 플랜트 사이의 간섭에 의해서 발생하는 비선형성을 감소시키는 역할을 한다. 모의시험 결과를 통해서 자속의 궤환이 자기부상 시스템의 부하변동에 대해서 Open-loop 성능 향상에 효과적임을 보인다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2006년도 추계학술대회 특별세미나 특별세션
• /
• pp.145-159
• /
• 2006

This paper describes the development of a clustering based fuzzy controller of an electromagnetic suspension vehicle using gain scheduling method and Kalman filter for a simplified single magnet system. Electromagnetic suspension vehicle systems are highly nonlinear and essentially unstable systems For achieving the levitation control of the DC electromagnetic suspension system, we considered a fuzzy system modeling method based on clustering algorithm which a set of input/output data is collected from the well defined Linear Quadratic Gaussian(LQG) controller. Simulation results show that the proposed clustering based fuzzy controller methodology robustly yields uniform performance with adequate gap response over the mass variation range.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1997년도 제26회 추계학술대회
• /
• pp.232-238
• /
• 1997

In this paper, a theoretical method is presented to design a hydraulic control valve system that consist of an important component in the hydraulic snubber. The hydraulic snubber is used essentially to support the piping systems at power plants. To calculate the force due to pressure drop and flow rate in the valve orifice and by-pass hole, Bernoulli equation is used. The Reynolds equation are numerically analyzed in the clearance gap between the valve cone and valve seat to estimate the friction force and leakage flow rate. Based on the detailed theoretical data, we developed successfully the hydraulic snubber for power plants.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.192-194
• /
• 2006

Backlash between meshing gear teeth causes impact, tracking error and undesired vibrations. It is usually minimized by precision gear, spring-loaded anti-backlash gears and precise mechanical adjustment. Although these techniques can help to reduce the backlash gap, its cost is relatively high and performance is limited. And the classic controller is insufficient to control the dynamic system with nonlinearity. For these reason, a fuzzy controller is proposed to compensate the backlash effect at a robot system. The input variables are position error and change in error. The output variable can be defined by input voltage of motor. The performance of a fuzzy controller is verified by comparing with a PID controller. The results show that the undesired vibration is suppressed. And then diminishing the position error is observed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 제39회 하계학술대회
• /
• pp.940-941
• /
• 2008

Recently, there are a great many research for magnetic levitation(Maglev) system. Maglev system is eco-friendly used in a place that is not friction. But Maglev is system that inductance is changed according to air-gap, so this is unstable system. In this paper, we simulate 1 Maglev actuator Control and we do an experience on 4 Maglev actuator system control. however, we get a problem of 4 maglev actuator control, because Maglev is 3 DOF(Degree of Freedom). so we control average err of 2 Maglev actuator in the rear.

• 한국안전학회지
• /
• 제12권4호
• /
• pp.47-56
• /
• 1997

This paper presents the vibration control of an engine mount featuring an ER(electro-rheological) fluid. The Bingham properties of the ER fluid to be employed to the ER engine mount are experimentally obtained through Coeutte type viscometer. The ER engine mount is devised ant its governing equation is derived. After evaluating the performance of the ER engine mount on the basis of the mathematical model, the novel type of the ER engine mount is then designed and manufactured. The electric field-dependent transmissibility of the ER engine mount is evaluated by changing the particle concentration and the electrode gap size. To investigate the control performance of the ER engine mount, neuro-control algorithm is adopted. It is shown that the proposed ER engine mount has prominent capabilities of controlling the damping force by tuning the electric fields and excellent vibration isolation performance.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제49권12호
• /
• pp.778-788
• /
• 2000

Chopper and sensors failures resulting from electric shock and mechanical vibration generated by rail irregularities are the serious problem deteriorating the performance in the electromagnetic suspension systems. Thus, this paper proposes a fault-tolerant control scheme with a dynamic compensator for the failure of the choppers, gap sensors and acceleration sensors in electromagnetic suspension system. The advantage of the proposed control method are demonstrated through simulation and experimental results for the levitation characteristics when the failures of the chopper and sensors occur, respectively.