• 한국기계가공학회지
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• 제3권3호
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• pp.86-92
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• 2004

This paper describes the properties of temperature-viscosity characteristics of hydrous and anhydrous electro-rheological fluids containing starch and titanium particle in silicone oil ER effects arise from electrostatic forces between the starch particles and titanium particles dispersed to the electrically insulating silicone oil induced when electric field is applied ER fluids under electric field control have been found to provide resonable estimates of ER fluid viscosity variation characteristics. Yield shear stress of the ER fluids were measured the couette cell type rheometer as a function of electrlc fields. The outer cup is connected to positive electrode(+) and bob becomes ground(-). The electrie field is applied by high voltage DC power supply. In this experiment shear rates were increased from 0 to 200 $s^{-1}$ in 2 minutes. The ER fluid's viscosity change is very small and stable at the temperature range of $40^{\circ}C$ to $60^{\circ}C$. Therefore, applications of a new ER fluid to control systems application are suitable.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.357-360
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• 1997

This paper presents a new anti-lock brake system(ABS) using electro-rheological(ER) valve actuators for the wheel slip control. The hydraulic dynamic model of the automotive brake system is formulated by incorporating electric field-dependent Bingham properties of ER fluid obtained experimentally. The brake system designed by this hydraulic model is able to control wheel slip by controlling the intensity of electric field which tunes the braking torque. The control fields of the ER valve to command desired wheel slip are determined by a sliding mode controller. A comparison between the proposed brake system and the conventional brake system is made by providing with computer simulations of vehicle motions under ABS performance requirement condition.

• 대한기계학회논문집A
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• 제23권6호
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• pp.1055-1064
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• 1999

In this wort ER(electro-rheological) clutch and MR(magneto-rheological) clutch are devised and their performance characteristics such as response time and controllability are compared. As a first step, field-dependent yield stresses of ER and MR fluids are distilled in shear mode. For reasonable comparison between two clutches, a nondimensional design model is established by choosing same design parameters of gap size and number. Following the manufacturing of two clutches, field-dependent torque level, response time to step input, mechanical Power generation to electric power consumption are experimentally measured and compared. In addition, in order to investigate torque controllability of the clutches a sliding mode controller is formulated and experimentally realized. Control bandwidths of two clutches are identified and tracking control responses for desired torque trajectories are presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.595-600
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• 2007

This paper presents a new jetting dispenser driven by a piezoelectric actuator at high operating frequency to provide very small dispensing dot size of adhesive in modern semiconductor packaging processes. After describing the mechanism and operational principle of the dispenser, a mathematical model of the structured system is derived by considering behavior of each component such as piezostack and dispensing needle. In the fluid modeling, a lumped parameter method is applied to model the adhesive whose rheological property is expressed by Bingham model. The governing equations are then derived by integrating the structural model with the fluid model. Based on the proposed model, dispensing performances such as dispensing amount are investigated with respect to various input trajectories.

• International Journal of Precision Engineering and Manufacturing
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• 제2권2호
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• pp.48-56
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• 2001

This paper presents the position tracking control of a closed-loop cylinder system using electro-rheological (ER) valve actuators. After manufacturing three sets of cylindrical ER valves on the basis of Bingham model of ER fluid, a 3 dof(degree-freedom) closed-loop cylinder system having the heave, roll and pitch motions is constructed. The governing equations of motion are derived using Lagrange's equation and a control model is formulated by considering nonlinear characteristics of the system, Sliding mode controllers are the designed for these ER valve actuators in order to achieve position tracking control. The effectiveness of trajectory tracking control performance of the proposed cylinder system is demonstrated through computer simulation and experimental implementation of the sliding mode controller.

• 소음진동
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• 제11권1호
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• pp.41-48
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• 2001

This paper presents vibration control performance of a passenger vehicle featuring magneto-rheological (MR) suspension units. As a first step, a cylindrical shock absorber is designed and manufactured on the basis of Bingham Property of a commercially available MR fluid. After verifying that the damping force of the shock absorber can be controlled by the intensity of magnetic field(or input current), it is applied to a full-car model. An optimal controller is then formulated to effectively suppress unwanted vibration of the vehicle system. The control performances are evaluated via hardware-in-the-loop simulation(HILS), and presented in both time and frequency domains.

• 동력기계공학회지
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• 제16권6호
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• pp.92-97
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• 2012

In this study, ER fluids were working fluid and yield shear stress of attained dispersive ER fluids made by analyzed to adapt effectively at the practical equipment like three port ER valve. In addition, movement of ER particle was observed by using a microscope the same as the strength of electric field with Bingham characteristic. Basis material was presented to develop 3 port ER-Valve by quantitatively comparing and analyzing entrance, load and outlet flow's differences of 3 port rectangular tubes. This study, after designing and producing the 3port ER-Valve, considered the characteristic of pressure drop, outlet and load flow rate by changing the strength of electric field on ER fluids flowing between electrodes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.546-549
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• 1995

This paper presents a control of washing machine using ER clutch and brake actuators. After analyzing field- dependent torque of the actuators on the basis of Bingham model of the ER fluid, two sets of cylindrical ER clutch and brake are manufactured. The governing equation of motion for washing and dehydrating are derived by considering actuators' dynamics. Subsequently, PID controllers are designed to achieve desired rotational motions and tracking control results are provided to demonstrate the effectiveness of the proposed method.

• 한국소음진동공학회논문집
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• 제18권4호
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• pp.432-438
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• 2008

This paper presents a new jetting dispenser driven by a piezoelectric actuator at high operating frequency to provide very small dispensing dot size of adhesive in modern semiconductor packaging processes. After describing the mechanism and operational principle of the dispenser, a mathematical model of the structured system is derived by considering behavior of each component such as piezostack and dispensing needle. In the fluid modeling, a lumped parameter method is applied to model the adhesive whose rheological property is expressed by Bingham model. The governing equations are then derived by integrating the structural model with the fluid model. Based on the proposed model, dispensing performances such as dispensing amount are investigated with respect to various input trajectories.

• Tribology and Lubricants
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• 제19권2호
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• pp.72-77
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• 2003

Chitosan derivatives, Fluorinated chitosan, and N,N,N-Trimethyl chitosan iodide were synthesized as the disperse phases for the electrorheological fluid. The synthesis of these materials were confirmed by Fourier transform infrared spectroscopy (FT-lR). Chitosan derivative suspensions showed ER effect under the electric field. Especially, N,N,N-Trimethyl chitosan iodide suspension showed better electrorheological and electric properties than Fluorinated chitosan. It is due to difference in electron strength of polar groups composed derivatives. N,N,N-Trimethyl chitosan iodide suspension exhibited a linear dependence on an electric field power of 2.07.