• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.155-163
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• 1996

This paper presents vibration and position tracking control of a smart structure using shape memory alloy(SMA) actuators. A governing equation of motion of the proposed structure is obtained via Hamilton's princeple. The dynamic characteristics of the SMA actuator are experimentally identified and incorporated with the governing equation to furnish a control system model. Subsequently, a sliding mode controller which has inherent robustness to external disturbances is formulated on the basis of the sliding mode conplacement, and also for the position tracking control of desired trajectories with low-frequency sine and square waves.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.8
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• pp.146-154
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• 1997

Solenoid-folw control type ABS is used with a 'dump and reapply' pressure control arrangement instead of using 2/2 (normal open/close) solenoid valves in convensional systems(sol. -sol. control type), a flow control valve is used which replaces the (no) inlet valve. The flow control valve controls fluid flow providing a nearly constant reapply rate( .theta. ) after the dump plase of ABS operation. In this study, to investigate a characteristics of brake pressure by PWM control, test rig was consisted of ABS hydraulic modulator, digital controller, pneumatic power supply and brake master cylinder. For comparison with experi- mental results, system modelling and computer simulation were performed. As a result, experiment results showed fairly agreement with the simulation. Also, it is shown that the pressure gradient (tan .theta. ) is affected by pressure, frequency, duty ratio and expressed with an exponential funtion.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.25-33
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• 1997

This study deals with controlling the velocity of Electr-Hydraulic servo system through the non-stan-dard PIC control. This was done as follows. First, we modeled nonlinearised model and linearised model, second designed analytic program for electro-hydraulic servo system velocity control Lastly, to im- prove dynamic characteristics of system we designed non-standard PID contoller and verifed throughth experi- ment and MATLAB program, commercial used software.

• Journal of Auto-vehicle Safety Association
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• v.15 no.2
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• pp.13-20
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• 2023

This paper presents a fault tolerant control strategy for Steer-by-Wire (SbW) systems. Among many problems to be solved before commercialization of SbW systems, maintaining reliability and fault tolerance in such systems are the most pressing issues. In most previous studies, dual steering motors are used to achieve actuation redundancy. However, relatively few studies have been conducted to introduce fault tolerant control strategies using rear wheel steering system. In this work, an actuator fault in front wheel steering is compensated by active rear wheel steering. The proposed fault tolerant control algorithm consists of disturbance observer and sliding mode control. The fault tolerant control performance of the proposed approach is validated via computer simulation studies with Carsim vehicle dynamics software and MATLAB/Simulink.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1147-1154
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• 2012

In this study, a method for designing blade pitch and generator torque controllers for a wind turbine generator is presented. This method consists of two steps. First, the Lyapunov stability theory is used to obtain nonlinear control laws that can regulate the rotor speed and the power output at all operating ranges. The blade pitch controller is chosen such that it always decreases a positive definite function that represents the error in rotor speed control. Similarly, the generator torque controller always decreases a positive definite function that reflects the error in power output control. Then, the simulation-based optimization technique is used to tune the design parameters. The controller design procedure and simulation results are presented using the widely adopted two-mass model of the wind turbine.

• Journal of the KSME
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• v.57 no.10
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• pp.48-52
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• 2017

이 글에서는 공간적으로 형상 제어된 나노구조물의 자기조립화(self-assembly)를 이용하여 고용량의 이온흐름이 가능한 나노전기수력학 기술에 대한 소개와 더불어, 이를 활용한 이온 다이오드, 고효율 마이크로 믹서, 이온농도차 발전 응용 및 향후 생체 내 이온검출 센서, 인체 삽입형 디바이스, 뇌-기계 인터페이스 연구에 대한 전망을 소개하고자 한다.

• Journal of the Korean Society of Visualization
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• v.17 no.1
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• pp.3-9
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• 2019

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.55-56
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• 2012

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.2
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• pp.183-190
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• 1982

이 논문에서는 유압제어장치의 응답에 대하여 관성하중, 점성하중, 쿨룸(Coulomb)마찰 및 입력 신호의 주파수가 시스템에 미치는 영향을 고찰하였고, 이에 따른 속도와 압력파형을 주로 서 술하였다. 피스톤의 드리프트(drift)와 스프링하중을 제외한 대부분의 요소가 고려되었다. 추출된 방정식은 모두 무차원화 하였으며 입력 신호를 계단함수로 할 때에는 위치 피이드백 (feedback)이 삽입되었다.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.702-707
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• 2004

In this paper, we proposed the decoupling VSS controllers for a trajectory control of a two degrees of freedom SCARA type manipulator. We decoupled the position and velocity of a manipulator tip by using a nonlinear error functions. The reference inputs of the controller can be decided directly from the desired position and velocity. Simulation result is provided to verity the effectiveness of the proposed control scheme.