• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.2
• /
• pp.221-230
• /
• 1988

In the microcomputer-based velocity control for an electro-hydraulic servo system, the effects of control methods and control hardware on the performance of the system were investigated. Experiments were carried out with PID and deadbeat controllers using 8 or 16 bit microprocessor and 8 or 12 bit A/D and D/A converters. It is found that the transient response of the system is better with PID controller than with deadbeat controller. When the number of bits of the microprocessor and converters are small, it is also found that amplitude quantization due to limited word-length gives significant effects on transient responses of the system. Analytically predicted step responses are in good agreement with experimental ones.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.12
• /
• pp.89-95
• /
• 2003

A PID controller integrated with a velocity feedback is designed for fluid power elevator model system in this study. In this case, for outside disturbance load a hydraulic cylinder and a pressure control valve are used. In this method overshoot is reduced and settling time becomes also shorter than the values achieved from the PID controller system only In conclusion a PID controller integrated with a velocity feedback is considered a suitable control method for fluid power elevator system.

• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.452-454
• /
• 2008

본 논문에서는 실험적으로 구한 엔진 토크 참조 표를 이용하여 엔진의 비선형 모델을 구하고 이를 각각의 운전 점에 대해 선형화한 엔진 모델을 제시하였다. 이러한 선형화된 엔진 모델을 이용하여, 전기식 조속기를 사용한 디젤 엔진의 속도 제어에 있어 발생하는 안정성 문제를 해석하였다. 제시한 디젤 엔진 모델을 이용하여 속도제어기의 비례, 적분 미분 이득을 설정하고 이 값을 바탕으로 모의실험 및 실험을 통하여 제시한 모델의 타당성을 검증 하였다.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.7
• /
• pp.106-112
• /
• 2000

The purpose of this paper is to study on the control of the engine idle speed under sudden A/C load which is one of the most severe disturbances on engines. Three types of the closed-loop controller are developed for the stable engine idle speed control. The input of the controller is an error of rpm. The output of the controller is an ISCV duty cycle. The anticipation delay is considered to deal with the delay time of the air mass in engine. The PID, Fuzzy and PID-type Fuzzy controllers with the anticipation delay have improved the engine idle speed condition more than current ECU map table under the A/C load.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2001.05a
• /
• pp.225-230
• /
• 2001

In this paper, a method for optimal design of PID controller using the immune algorithm(IA) has been proposed to improve the stability of A.C.-D.C. power system. The process of this study is composed of formulation of basic controls on HVDC transmission system, mathematical model preparation for stability analysis, and supplementary signal control by an optimal PID controller using the IA. The dynamic property was verified through computer simulations regarding transient stability.

• Journal of Drive and Control
• /
• v.9 no.4
• /
• pp.58-61
• /
• 2012

The customers who used the hydroulic system desire the product that has more detailed specification quickly during the industrial technology is developed. Every researcher try to reduce the developed period and to satisfy the customers' desire. Lot's of simulation software and hardware already was used to be satisfied those purpose. But these kind of equipment need a lot of cost to set up and technical knowledge to drive that system. This paper concerns about analog PID controller that can be assembled with a few resistor, condenser and optional amplifier and doesn't need technical knowledge to drive. At the first, the plant was modeled mathematically to design the analog PID controller's circuit. After that, PID controller's parameter was selected by customers' desire. Finally, the analog PID controller's circuit was assembled from the control law. The circuit's availability was confirmed by step response test in the controlled system.

• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.146-151
• /
• 2001

The Grand-Touring is a game motion simulator that simulates the race-car driving motion with three hydraulic cylinders which connect the platform and base in parallel. Its motion control system consists of the PC-based main controller and micro-controller based sub-controller. The former one process the dynamic image of race-car in response to the driver's action and computes the reference command for each cylinder and the latter one is designed for the tracking control of hydraulic cylinder and interfacing the auxiliary signals between various sensors/actuator and main controller. In this research, we developed the sub-controller that implements the required functions of Grand-Touring and prove the overall performance with experiments.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.4
• /
• pp.332-337
• /
• 1997

디스크립터(Descriptor) 표현은 상태공간 표현을 확장시킨 일반적인 시스템의 기술방법으로 파라미터의 물리적인 구조를 보존하고 있으며, 임펄스를 포함한 현상을 기술할 수 있다. 또한, 대규모 시스템의 모델화가 용이하며, 프로퍼(Proper)이지 않은 시스템을 기술할 수 있고 구속조건을 가진 동적시스템의 기술이 가능하는 등의 특징을 지니고 있다. 그러나, 디스크립터 시스템의 해는 미분항을 포함하고 있으므로 노이즈 및 파라미터 변동에 대해서 매우 민감하여, 관측기설계시 강인(Robust)한 관측기설계가 요구된다. 본 논문에서는 디스크립터 시스템에 대해 로바스트 관측기의 일종인 비례적분(PI) 관측기의 설계에 대해서 논한다. 먼저, 디스크립터 시스템에 대한 PI 관측기의 존재조건을 유도하였으며, 체계적인 설계법을 보였다. 또한, PI 관측기의 존재조건이 Rosenbrock의 가관측 조건하에서 간단히 보여지며, 이것은 시스템 행렬의 Rank 조건에 의해 쉽게 구해질 수 있다.

• Proceedings of the KAIS Fall Conference
• /
• 2009.05a
• /
• pp.244-248
• /
• 2009

본 논문에서는 만타형상의 무인잠수정의 운동성능과 제어기설계에 대한 성능을 확인하기 위한 수학모델을 정립하여 시뮬레이션 프로그램을 개발하였다. 본 논문에 사용된 수학모델은 6자유도 운동방정식을 이용하여 Matlab / Simulink를 이용하여 시뮬레이션 프로그램을 개발하였다. 개발된 시뮬레이션 프로그램을 이용하여 만타형상무인잠수정(Manta-type unmanned underwater test vehicle)의 동역학적 운동성능을 해석하였으며, 무인잠수정의 제어성능을 해석하기 위하여 PID(비례-미분-적분)제어기와 슬라이딩모드(Sliding mode)제어기를 설계하여 만타형상무인잠수정의 제어 성능을 해석하였다. 설계된 제어기는 무인잠수정의 수심제어와 방향각제어에 사용되었다. 설계된 제어기의 성능을 확인하기 위하여 미국 해군대학원(Naval Postgraduate School)의 AUV II와 비교하였다. 설계된 수심제어와 방향각 제어기를 이용하여 만타형무인잠수정의 설계 목표에 부합하는 항해제어시뮬레이션을 실시하였다.

• Journal of Drive and Control
• /
• v.13 no.3
• /
• pp.15-23
• /
• 2016

The direct-drive servo valve(DDV) is a kind of one-stage valve because the main spool valve is directly driven by the dc motor. Since the DDV structure is simple, it is less expensive, more reliable, and offers a reduced internal leakage and a reduced sensitivity to fluid contamination. The control system of the DDV is highly nonlinear due to a current limiter, a voltage limiter, and the flow-force effect on the spool motion. The shape of the step response of the DDV-control system varies considerably according to the magnitudes of the step input and the load pressure. The system-design requirements mean that the overshoots should be less than 20%, and the errors at 0.02s should be less than 2%, regardless of the reference-step input sizes of 1V and 5V and the load-pressure magnitudes of 0MPa and 20.7MPa. To satisfy the system-design requirements, the PID-controller parameters of $K_c$, $T_i$ and $T_d$, and the derivative-feedback gain of $K_{der}$ are designed using the root locus and manual tuning.