• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1983-1989
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• 2005

Industrial robots are powerful, extremely accurate multi-jointed systems, but they are heavy and highly rigid because of their mechanical structure and motorization. Therefore, sharing the robot working space with its environment is problematic. A novel pneumatic artificial muscle actuator (PAM actuator) has been regarded during the recent decades as an interesting alternative to hydraulic and electric actuators. Its main advantages are high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks. The PAM is undoubtedly the most promising artificial muscle for the actuation of new types of industrial robots such as Rubber Actuator and PAM manipulators. However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. In addition, the nonlinearities in the PAM manipulator still limit the controllability. Therefore, it is not easy to realize motion with high accuracy and high speed and with respect to various external inertia loads in order to realize a human-friendly therapy robot To overcome these problems a novel controller, which harmonizes a phase plane switching control method with conventional PID controller and the adaptabilities of neural network, is newly proposed. In order to realize satisfactory control performance a variable damper - Magneto-Rheological Brake (MRB) is equipped to the joint of the manipulator. Superb mixture of conventional PID controller and a phase plane switching control using neural network brings us a novel controller. This proposed controller is appropriate for a kind of plants with nonlinearity uncertainties and disturbances. The experiments were carried out in practical PAM manipulator and the effectiveness of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase plane switching control using neural network and without regard for the changes of external inertia loads.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.550-559
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• 2006

This paper presents designs and performance investigations of two bypass-type MR (magneto-rheological) shock dampers for high impulsive force systems, one of which is with single rod and the other with double rod. First of all, on the basis of the Bingham properties of the MR fluid and the magnetic field analysis of the magnetic circuit, the MR shock dampers are designed and manufactured. After experimental investigations on their magnetic field-dependent damping forces and responses characteristics, dynamic models of the proposed dampers are formulated and compared. Then, a simple 1 degree-of-freedom mass-drop system is constructed, and the effective and practical control algorithm is designed by considering dynamic characteristics of the shock control system. The shock control performances of the proposed MR shock dampers are verified through the comparison study of experiment results with simulation ones.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.3 s.73
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• pp.233-238
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• 2006

In this paper, mixed mode magneto-rheological(MR) damper, which is applicable for vibration control of a small scale multi-story structure, is devised. First, the schematic configurations of the shear, flow, and mixed mode MR dampers are described with design constraints and then the analytical models to predict the field-dependent damping forces are derived for each type. Second, an appropriate size of the mixed mode MR damper is manufactured and its field-dependent damping characteristics are evaluated in time domain. Finally, the performance of the manufactured MR damper which is semi-actively applied to a small scale building excited by earthquake load, is numerically evaluated.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.69-76
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• 2000

Lots of semi-active control devices have been developed in recent years because they have the best features of passive and active system. Especially, controllable magneto-rheological(MR) fluid devices have received significant attention in these area of research. The MR fluid is the material that reversibly changes from a free-flowing, linear viscous fluid to a semisolid with a controllable yield strength in milliseconds when exposed to a magnetic field. If the magnetic field is induced by moving a permanent magnet instead of applying current to a solenoid, it is possible to design a MR damper consuming low power because the power consumption is reduced at steady state. This paper proposes valve mode MR damper using permanent magnetic circuit that has wide range of operation with low power consumption, a design parameter is adopted. The magnetic circuit, material of choke and choke type are selected experimentally with the design parameter. The behaviors of the damper are examined and torque tracking control using PID feedback controller is performed for step, ramp and sinusoidal trajectiories.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.248-253
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• 2013

The maximum speed is one of the most important performance in high speed railway vehicle. The higher the train speed is, the worse the ride comfort is, In order to solve this problem, a semi-active or active suspension can be applied to high speed railway vehicle. The variable damper with hydraulic solenoid valve is used in the semi-active suspension. But the variable damper with hydraulic solenoid valve requires tank for supplying fluid. The MR(Magneto Rheological) damper can be considered instead of hydraulic variable damper which needs additional device, i.e. reserver tank for fluid. In the case of active suspension, hydraulic actuator or electro-mechanical one is used to suppress the carbody vibration in railway vehicle. In this study the MR damper and electro-mechanical actuator was considered in secondary suspension system of high speed railway vehicle. The dynamic analysis was performed by using 10-DOF dynamic equations of railway vehicle. The performance of the semi-active suspension and active suspension system were reviewed by using MATLAB/Simulink S/W. The vibration suppression effect of semi-active and active suspension system were investigated experimentally by using 1/5-scaled railway vehicle model.

• Wind and Structures
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• v.21 no.5
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• pp.565-595
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• 2015

In recent years, high-rise buildings received a renewed interest as a means by which technical and economic advantages can be achieved, especially in areas of high population density. Taller and taller buildings are being built worldwide. These types of buildings present an asset and typically are built not to fail under wind loadings. The increase in a building's height results in increased flexibility, which can lead to significant vibrations, especially at top floors. Such oscillations can magnify the overall loads and can be annoying to the top floors' occupants. This paper shows that increased stiffness in high-rise buildings may not be a feasible solution and may not be used for the design for comfort and serviceability. High-rise buildings are unique, and a vibration control system for a certain building may not be suitable for another. Even for the same building, its behavior in the two lateral directions can be different. For this reason, the current study addresses the application of hybrid tuned mass and magneto-rheological (TM/MR) dampers that can work for such types of buildings. The proposed control scheme shows its effectiveness in reducing floors' accelerations for both comfort and serviceability concerns. Also, a dissipative analysis carried out shows that the MR dampers are working within the possible range of optimum performance. In addition, the design loads are dramatically reduced, creating more resilient and sustainable buildings. The purpose of this paper is to stimulate, shape, and communicate ideas for emerging control technologies that are essential for solving wind related problems in high-rise buildings, with the objective to build the more resilient and sustainable infrastructure and to optimally retrofit existing structures.

• Smart Structures and Systems
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• v.23 no.1
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• pp.1-14
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• 2019

Control algorithms are the most important aspects in successful control of structures against earthquakes. In recent years, intelligent control methods rather than classical control methods have been more considered by researchers, due to some specific capabilities such as handling nonlinear and complex systems, adaptability, and robustness to errors and uncertainties. However, due to lack of learning ability of fuzzy controller, it is used in combination with a genetic algorithm, which in turn suffers from some problems like premature convergence around an incorrect target. Therefore in this research, the introduction and design of the Fuzzy Cooperative Coevolution (Fuzzy CoCo) controller and Adaptive Neural-Fuzzy Inference System (ANFIS) have been innovatively presented for semi-active seismic control. In this research, in order to improve the seismic behavior of structures, a semi-active control of building using Magneto Rheological (MR) damper is proposed to determine input voltage of Magneto Rheological (MR) dampers using ANFIS and Fuzzy CoCo. Genetic Algorithm (GA) is used to optimize the performance of controllers. In this paper, the design of controllers is based on the reduction of the Park-Ang damage index. In order to assess the effectiveness of the designed control system, its function is numerically studied on a 9-story benchmark building, and is compared to those of a Wavelet Neural Network (WNN), fuzzy logic controller optimized by genetic algorithm (GAFLC), Linear Quadratic Gaussian (LQG) and Clipped Optimal Control (COC) systems in terms of seismic performance. The results showed desirable performance of the ANFIS and Fuzzy CoCo controllers in considerably reducing the structure responses under different earthquakes; for instance ANFIS and Fuzzy CoCo controllers showed respectively 38 and 46% reductions in peak inter-story drift ($J_1$) compared to the LQG controller; 30 and 39% reductions in $J_1$ compared to the COC controller and 3 and 16% reductions in $J_1$ compared to the GAFLC controller. When compared to other controllers, one can conclude that Fuzzy CoCo controller performs better.

• Smart Structures and Systems
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• v.19 no.4
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• pp.351-360
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• 2017

Protection of structures against natural hazards such as earthquakes has always been a major concern. Semi-active control combines the reliability of passive control and versatility and adaptability of active control. So it has recently become a preferred control method. This paper proposes an algorithm based on Uniform Deformation Theory to mitigate vulnerable buildings using magneto-rheological (MR) damper. Due to the successful performance of fuzzy logic in control of systems and its simplicity and intrinsically robustness, it is used here to regulate MR dampers. The particle swarm optimization (PSO) algorithm is also used as an adaptive method to develop a fuzzy control algorithm that is able to create uniform inter-story drifts. Results show that the proposed algorithm exhibited a desirable performance in reducing both linear and nonlinear seismic responses of structures. Performance of the presented method is indicated in compare with passive-on and passive-off control algorithms.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1170-1178
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• 2007

Repeated hardware tests and tuning, investing cost and time, are usually required to assure a satisfactory performance of the suspension seat. In this study, an EILS(ECU-in-the-loop) method was proposed to develop a controller for a semi-active suspension seat with a MR(magneto-rheological) damper. EILS system was developed using a real-time seat dynamics model communicating with ECU hardwares under a closed loop environment utilizing Matlab/Simulink and xPC $TargetBox^{TM}$. A sky-hook based control algorithm with optimized damping coefficients was verified to reduce the energy consumption and to improve the vibration response performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1159-1165
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• 2011

This paper presents ride comfort characteristics of a quarter-vehicle magneto-rheological(MR) suspension system with respect to different tire pressure. As a first step, controllable MR damper is designed and modeled based on both the optimized damping force levels and mechanical dimensions required for a commercial full-size passenger vehicle. Then, a quarter-vehicle suspension system consisting of sprung mass, spring, tire and the MR damper is constructed. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of the quarter-vehicle MR suspension system. Finally, the ride comfort analysis with respect to different tire pressure is undertaken in time domain. In addition, a comparative result between controlled and uncontrolled is provided by presenting vertical RMS displacement.