• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.3
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• pp.39-50
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• 2009

In this paper, a method for reducing seismic responses of adjacent buildings is studied that involves connecting two buildings with energy-dissipating devices, such as MR dampers. For the vibration control of the adjacent buildings, a fuzzy control technique with semi-active MR dampers is proposed. A fuzzy controller, which can appropriately modulate the damping forces by controlling the input voltage in real time, is designed according to the proposed method. To verify the validity of the proposed method, numerical simulations are performed. In the numerical simulations, historical earthquake records with diverse frequency contents and different peak values are used. For the purpose of comparison, an uncontrolled system, a passive control system and a semi-active fuzzy control system are considered. The comparative results prove the effectiveness of the proposed control technique, i.e. the numerical results show that the fuzzy controlled semi-active MR dampers can effectively reduce the earthquake responses of the adjacent structures.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1929-1934
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• 2011

Recently the maximum speed becomes the most important performance in high speed train. But the speed up of train will not give the passenger good riding comfort. The semi-active suspension system by using variable damper with hydraulic solenoid valve is used to solve this problem. But the variable damper with hydraulic solenoid valve requires tank for supplying fluid. In this study, the MR(Magneto Rheological) damper was considered instead of hydraulic variable damper in order to improve riding comfort. Dynamic simulation was conducted for semi-active suspension system with MR damper was made by using Matlab-Simulink S/W. According to control strategy of MR damper for improving ride comfort in railway vehicle, The riding comfort of the railway vehicle with semi-active suspension system was analyzed and compared with conventional suspension system by using the program.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.438-441
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• 1997

This paper studies a semi-active suspension with ER damper controlled Fuzzy Net Controller designed GA(Genetic Algorithm). Apparent viscosity of ERF(Electro-Rheological Fluid) can be changed rapidly by applying electric field. Semi-active suspension for ground vehicles are expected to improve ride quality with less vibration. This paper deals with a two-degree -of-freedom suspension using the ER damper for a quarter vehicle system. In this paper, the GA is applied for generating Fuzzy Net Controllers. The GA designs the optimal structure and performance of Fuzzy Net Controller having hybrid structure. Computer simulation results show that the semi-active suspension with ER damper has good performances of ride quality.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.1
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• pp.17-23
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• 2004

The semi-active suspension system is getting widely adopted in passenger vehicles for its ability to improve ride comfort over the passive suspension system while not degrading driving safety. A key to the success is to develop practical controllers that yield performance enhancement over the passive damper under various driving conditions. To this end, several control strategies have been studied and evaluated in this research in consideration of practical aspects such as nonlinearity and dynamics of the damper. From simulation results. it has been observed that, with the proposed control schemes, ride comfort can be significantly upgraded while suppressing degradation of driving safety.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.452-457
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• 2000

This paper presents control response of a semi-active electro-rheological(ER) suspension. After showing dynamic characteristics of the ER damper, 1/4 car model is formulated by incorporating with the time constant of the damping force. $H_{\infty}$ controller compensating mass and time constant uncertainties is then designed in order to suppress vibration level of the suspension. The control responses such as vertical acceleration are presented.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.114-114
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• 2000

In this paper a self-tuning modified skyhook control for the semi-active suspension systems is investigated. The damping force generation mechanism is modeled We consider a 2 DOF time-varying quarter car model that permits parameter variations of the sprung mass and suspension spring coefficient. The modified skyhook control algorithm proposed in this paper requires only the measurement of body acceleration. The absolute velocity of the sprung mass and the relative velocity of the suspension deflection are estimated by using integral filters, according to parameter variations. The skyhook gains are designed in such a way that the body acceleration and the dynamic tire force are optimized. An ECU prototype will be discussed

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.104-111
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• 1999

A semi-active suspension system for a vehicle using an Electrorheological Fluid damper has been studied. Apparent viscosity of ERF(Electrorheological Fluid) can be changed rapidly by applying electric field. The damping force of ER damper can be selectively controlled by employing electric field to the ER fluid domain. This paper deals with a two-degree-of-freedom suspension using the ER damper for a quarter car model. An intelligent control method using fuzzy control with genetic algorithm has been employed to control the damping force of the ER damper. The GA designs the optimal structure and performance of Fuzzy Net Controller having hybrid structure. The designed fuzzy net controller has been compared with the skyhook type controller for a quarter car model. The computer simulation results show that the semi-active suspension with ER damper has a good performance in the sense of ride quality with less vibration for ground vehicle.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.449-456
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• 2003

Hybrid semi-active control system is applied to improve the seismic peformance of the building structure against earthquake excitation and the LQR-based semi-active control algorithm is developed to tune the integrated stiffness/damping characteristics of the hybrid system complementarily. Numerical simulation for a 8-story shear building has been carried out to verify the applicability and effectiveness of the proposed method. Analysis results showed that the hybrid system can be a compromising solution to the seismic response control problem, compared with conventional variable stiffness or variable damping systems. Comparison results proved that the proposed algorithm can perform refined tuning of the stiffness and damping coefficients of the hybrid semi-active control system better than sliding mode control algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.961-962
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• 2012

• Smart Structures and Systems
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• v.8 no.5
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• pp.501-524
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• 2011

Recent studies have discovered that a conventional passive isolation system may suffer from an excessive isolator displacement when subjected to a near-fault earthquake that usually has a long-period velocity pulse waveform. Semi-active isolation using variable friction dampers (VFD), which requires a suitable control law, may provide a solution to this problem. To control the VFD in a semi-active isolation system more efficiently, this paper investigates experimentally the possible use of a control law whose control logic is similar to that of the anti-lock braking systems (ABS) widely used in the automobile industry. This ABS-type controller has the advantages of being simple and easily implemented, because it only requires the measurement of the isolation-layer velocity and does not require system modeling for gain design. Most importantly, it does not interfere with the isolation period, which usually decides the isolation efficiency. In order to verify its feasibility and effectiveness, the ABS-type controller was implemented on a variable-friction isolation system whose slip force is regulated by an embedded piezoelectric actuator, and a seismic simulation test was conducted for this isolation system. The experimental results demonstrate that, as compared to a passive isolation system with various levels of added damping, the semi-active isolation system using the ABS-type controller has the better overall performance when both the far-field and the near-fault earthquakes with different PGA levels are considered.