• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1040-1043
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• 1996

The accuracy of the servo control in CNC system has a great influence on the duality of machine product. Tracking performance of the servo control is deteriorated mainly by the time delay of the servo system and the inertia of the work table or bed. Contouring errors occur in every interpolation steps by the effect of the tracking performance. In this paper, $H_{\infty}$ two-degree-of-freedom(TDF) controller is designed for improvement to improve the tracking performance. The designed controller is applied 3-axis machining center model and the cutting accuracy is simulated in case of corner cutting, circular and involute interpolation. Simulation results show that $H_{\infty}$ TDF controller designed in this paper has a good effect to improve tracking performance in CNC system.

• 로봇학회논문지
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• 제19권2호
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• pp.139-148
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• 2024

In this paper, we propose a two-degree-of-freedom snake robot head system and an I-PID (Intelligent Proportional-Integral-Derivative)-based controller utilizing RBF (Radial Basis Function) neural network and adaptive robust terms as a control strategy to reduce rotation occurring in the snake robot head. This study proposes a two-degree-of-freedom snake robot head system to avoid complex snake robot dynamics. This system has a control system independent of the snake robot. Subsequently, it utilizes an I-PID controller to implement a control system that can effectively manage rotation at the snake robot head, the robot's nonlinearity, and disturbances. To compensate for the time delay estimation errors occurring in the I-PID control system, an RBF neural network is integrated. Additionally, an adaptive robust term is designed and integrated into the control system to enhance robustness and generate control inputs responsive to signal changes. The proposed controller satisfies stability according to Lyapunov's theory. The proposed control strategy was tested using a 9-degreeof-freedom snake robot. It demonstrates the capability to reduce rotation in Lateral undulation, Rectilinear, and Sidewinding locomotion.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.569-572
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• 1996

Explicit state-space formulate for an H$_{.inf}$ based two-degrees-of-freedom robust controller are derived in discrete-time. The controller provides robust stability against coprime factor uncertainty, and a degree of robust performance in the sense of making the closed-loop system match a prespecified reference model. It is shown that the controller consists of a plant observer, the chosen reference model, and a generalized state feedback law associated with the plant and model states. The controller structure is shown to be relatively simple and thus may reduce the computational load on the digital control processor.

• 전자공학회논문지SC
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• 제38권1호
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• pp.14-26
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• 2001

본 논문에서는 다변수 시스템을 제어하는 경우 효율적인 제어를 어렵게 만드는 입력과 출력 사이의 결합 효과를 제거하는 비결합 제어기를 설계하였다. 설계된 제어기는 비결합 조건뿐만 아니라 제어계의 성능을 동시에 고려할 수 있는 2자유도 구조를 가지고 있다. 또한 제어기의 계산을 용이하게 하기 위하여 플랜트를 표준모델로 확장시킨 후 전달 행렬을 상태공간 계수로 표현하였다. 그리고 제어기의 계수값들은 선형 행렬 부등식을 이용하여 블록꼴 최적화 문제로 설정하여 구했기 때문에 비결합 및 성능 최적화에 초점을 둔 비결합 제어기의 $H_2$ 설계를 하는데 있어 효과적인 방법을 제시하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1110-1115
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• 2004

Water covers two-thirds of the earth and has a great influence on the future existence of all human being. Thailand has extensive coastline and near shore water that contain vast biological and mineralogical resources. The rivers and canals can be found around the country especially in the Bangkok, which once called the Venice of the East. Autonomous underwater robot (AUR) will be soon a tool to help us better understand water resources and other environmental issues. This paper presents the design and basic control of a six-degree of freedom AUR "Chalawan", which was constructed to be used as a testbed for shallow. It is a simple low cost open-frame design, which can be modified easily to supports various research areas in the underwater environment. It was tested with a conventional proportional-integral-derivative (PID) controller. After fine-tuning of the controller gains, the results showed the controller's good performances. In the future, the dynamic model of the robot will be analyzed and identified. The advanced control algorithm will be implemented based on the obtained model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.687-693
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• 1989

A robust deterministic control for a class of singularly perturbed uncertain systems, where uncertainties are characterized deterministically rather than stochastically, is developed based mainly on information available on an uncertain reduced-order system. The deterministic control scheme is applied to the motion control of a n degree of freedom robotic manipulator. The parasitic actuator and sensor dynamics of the manipulator are explicitly considered in the stability analysis of the deterministic controller using a singular perturbation model. Simulation and experimental studies for a two degree of freedom, direct drive SCARA manipulator are conducted to evaluate the effectiveness of the derived control scheme.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.395-398
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• 2001

본 논문에서는 직류 서보 전동기를 구동원으로 하는 위치 제어계에서 부하변동에 따른 파라메타 변화, 외란 둥에 강인한 2자유도 PID 제어기의 설계법을 제시하여 신경망으로 2자유도 PID 제어기를 구성하였다. 이 제어기의 계수들이 기동시나 계 응답의 변동시 신경망 역전파 알고리즘(Back-Propagation Algorithm)에 의해서도 수성 되도록 하였다. 그리고 이것을 실제의 위치 제어계에 적용하여 실험을 통해 그 성능을 검증하였다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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• pp.349-352
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• 2007

본 논문은 계층적 공정 경쟁 유전자 알고리즘(Hierarchical Fair Competition-based Genetic Algorithms : HFCGAs)을 이용한 회전형 역 진자 시스템의 최적 2-자유도 제어기 설계를 제안한다. 비선형이며 불안정한 운동을 하는 회전형 역 진자 시스템은 회전지렛대(rotating arm) 위의 폴(pole)이 적당한 제어력이 없는 상황에서 중력에 의해 어느 한 쪽 방향으로 넘어지려고 할 때, 외부에서 회전지렛대에 힘을 가하여 회전지렛대의 특정위치와 폴의 각도를 유지시키는 시스템으로, 본 논문에서는 두 개의 피드백 제어루프를 갖는 2-자유도 제어기를 구성한다. 각각의 제어기는 PD 제어기로 구성하고, 조기수렴 문제를 내재하고 있는 기존의 유전자 알고리즘의 해결방안중 하나인 HFCGAs를 이용하여 최적의 제어기 파라미터들을 구한다. 마지막으로 실제 공정에 적용하여 설계된 제어기의 성능을 평가한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.366-371
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• 1993

This paper gives a convenient parameterization for the clas of all stabilizing controllers in the presence of plant perturbation. The perturbations are constrained in such class as plants are stabilizable by a nominal controller. By using the controller stabilizing a given plant with perturbation, we can obtain a parametrization of all stable closed-loop transfer functions, which are affine in the free parameter of the controller. It is easy to extend the controller to the case of a two-degree-of-freedom controller.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.462-467
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• 2003

As for control systems, many researchers give optimal structures of the finite-word-length compensator. D. Williamson solved a fixed-point case against colored noise for the LQG problem. Recently, one of the authors derived an optimal filter against colored noise. And consequently, we apply the result to a twodegree-of-freedom control system in this paper. In addition the perturbation of the coefficients is considered. Furthermore, simulation results indicate this method gives better than other structures.