• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2046-2048
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• 2002

In this paper, I designed the inverter pendulum controller to controll the position of a wheel-chair. I used coefficient diagram method (CDM) to design the controller. The CDM is available, because it can make an engineer know all about the characteristic, stability, response time and robustness, of closed loop system. Writing this paper, I simulated the controller to know wheather is can controll the position of wheel-chair using the theorem of inverter pandulum controll, and I identified the usefulness of it.

• 전자공학회논문지SC
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• 제37권1호
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• pp.1-9
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• 2000

본 논문에서는 파라미터 변동 범위가 유한한 로봇 매니퓰레이터에 대한 출력궤환 강인제어기를 고이득 관측기를 사용하여 설계하였다. 적분제어를 포함하는 제안된 제어기는 이득제한에 따른 추종오차를 개선시키도록 하였다. 관절의 속도 측정치를 사용할 때의 문제점을 개선하기 위하여 고이득 관측기를 사용하였다. 미지의 파라미터 변동 범위에 대한 제한을 받지 않도록 제어기를 구성하였으며 전체 폐루프시스템의 상태궤적의 수렴성을 입증하였다. 제안된 방법을 2-링크 로봇 매니퓰레이터의 궤적제어에 적용하고 시뮬레이션을 통하여 성능을 확인하였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권1호
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• pp.111-118
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• 2004

In this paper, we present a novel approach for the structure of Fuzzy Neural Network(FNN) based on wavelet function and apply this network structure to the solution of the tracking problem for mobile robots. Generally, the wavelet fuzzy model(WFM) has the advantage of the wavelet transform by constituting the fuzzy basis function(FBF) and the conclusion part to equalize the linear combination of FBF with the linear combination of wavelet functions. However, it is very difficult to identify the fuzzy rules and to tune the membership functions of the fuzzy reasoning mechanism. Neural networks, on the other hand, utilize their learning capability for automatic identification and tuning. Therefore, we design a wavelet based FNN structure(WFNN) that merges these advantages of neural network, fuzzy model and wavelet transform. The basic idea of our wavelet based FNN is to realize the process of fuzzy reasoning of wavelet fuzzy system by the structure of a neural network and to make the parameters of fuzzy reasoning be expressed by the connection weights of a neural network. And our network can automatically identify the fuzzy rules by modifying the connection weights of the networks via the gradient descent scheme. To verify the efficiency of our network structure, we evaluate the tracking performance for mobile robot and compare it with those of the FNN and the WFM.

• 제어로봇시스템학회논문지
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• 제17권8호
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• pp.824-832
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• 2011

An essential consideration to differentiate prosthetic hand from robot hand is its convenience and usefulness rather than high resolution or multi-function of the robot hand. Therefore, this study proposes a myoelectric hand with a 2 DOF auto wrist module which has 6 essential functions of the human hand such as open, grasp, pronation, supination, extension, flexion, which improves the convenience of the daily life. It consists of the 3 main parts, the myoelectric sensor for input signal without additional attachment to operate the prosthetic hand, hand mechanism with high-torqued auto-transmission mechanism and self-locking module which guarantee the safety under the abrupt emergency and minimum power consumption, and dual threshold based controller to make easy for adopting the multi-DOF myoelectric hand. We prove the validity of the proposed system with experimental results.

• 제어로봇시스템학회논문지
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• 제16권8호
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• pp.780-785
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• 2010

The OPRoS (Open Platform for Robotic Services) framework is proposed as an application runtime environment for service robot systems. For the successful deployment of the OPRoS framework, fault tolerance support is crucial on top of its basic functionalities of lifecycle, thread and connection management. In the previous work [1] on OPRoS fault tolerance supports, we presented a framework-based fault tolerance architecture. In this paper, we extend the architecture with component-based fault tolerance techniques, which can provide more simplicity and efficiency than the pure framework-based approach. This argument is especially true for fault detection, since most faults and failure can be defined when the system cannot meet the requirement of the application functions. Specifically, the paper applies two widely-used fault detection techniques to the OPRoS framework: 'bridge component' and 'process model' component techniques for fault detection. The application details and performance of the proposed techniques are demonstrated by the same application scenario in [1]. The combination of component-based techniques with the framework-based architecture would improve the reliability of robot systems using the OPRoS framework.

• 대한전자공학회논문지
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• 제27권10호
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• pp.53-59
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• 1990

로보트 매니퓰레이터를 제어하는데 있어서, 토오크 계산법을 이용한 새로운 가변구조 모델 추종제어기를 설계한다. 슬라이딩 모드가 존재하기 위한 충부조건은 Lyapunov 함수에 의해 유도된다. 기준 모델은 이중 적분기를 사용하고 가속도 입력은 시스템의 안정성과 원하는 성능을 얻기 위하여 비례-미분 제어기로 구성한다. 제안된 제어기법은 매니퓰레이터 동력학 방정식 각 항들의 상한값과 추정값을 부여함으로써 정확한 매개변수의 지식과 역행렬 계산을 요구하지 않는다. 따라서 모의실험 결과 제어된 제어기가 목적궤적의 수렴성이 개선되었음을 보여준다.

• 제어로봇시스템학회논문지
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• 제10권10호
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• pp.869-877
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• 2004

This paper deals with motion planning algorithm for kinematically redundant manipulators that are not fixed to the ground. Differently from usual redundant manipulators fixed to the ground, the stability issue should be taken into account to prevent the robot from falling down. The typical ZMP equation, which is employed in human walking, will be employed to evaluate the stability. This work proposes a feed forward ZMP planning algorithm. The algorithm embeds the 'ZMP equations' indirectly into the kinematics of the kinematic model of a manipulator via a ZMP stability index The kinematic self motion of the redundant manipulator drives the system in such a way to keep or plan the ZHP at the desired position of the footprint. A sequential redundancy resolution algorithm exploiting the remaining kinematic redundancy is also proposed to enhance the performances of joint limit index and manipulability. In addition, the case exerted by external forces is taken into account. Through simulation for a 5 DOF redundant robot model, feasibility of the proposed algorithms is verified. Lastly, usual applications of the proposed kinematic model are discussed.

• 한국통신학회논문지
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• 제16권11호
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• pp.1186-1193
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• 1991

본 논문에서는 신경회로망을 사용한 로보트 매니퓰레이터의 궤적 제어 방법을 제안하였다. 매니퓰레이터에 가해지는 토크는 신경회로망이 출력인 feedforward 토크와 보조제어기로 사용되는 비례 미분 제어기PD 제어기의 출력인 feedback 토크의 합이다. 제안된 전경 회로망은 다층 신경회로로서 시간 지연 요소를 가지며 PD 제어기의 오차 토크를 사용하여 매니퓰레이터 이동력학 모델을 학습한다. errror backpropagation(BP) 학습 신경회로 제어기를 사용해보므로서 매니퓰레이터 동특성에 대한 정보를 미리 필요로 하지 않으며, 연결 가중치 값에 그러한 정보가 저장된다. 확인될 신경회로망의 특성을 컴퓨터 시뮬레이션을 통하여 입증한다.

• 제어로봇시스템학회논문지
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• 제14권3호
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• pp.236-241
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• 2008

This paper presents a method to recognize the plane regions for movement of walking robots. When the autonomous agencies using stereo camera or laser scanning sensor is under unknown 3D environment, the mobile agency has to detect the plane regions to decide the moving direction and perform the given tasks. In this paper, we propose a very fast method for plane detection using normal vector of a triangle by 3 vertices defined on a small circular region. To reduce the effect of noises and outliers, the triangle rotates with respect to the center position of the circular region and generates a series of triangles with different normal vectors based on different three points on the boundary of the circular region. The vectors for several triangles are normalized and then median direction of the normal vectors is used to test the planarity of the circular region. The method is very fast and we prove the performance of algorithm for real range data obtained from a stereo camera system.

• 제어로봇시스템학회논문지
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• 제22권6호
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• pp.411-416
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• 2016

This paper presents the design methodology of an unknown input observer for Lipschitz nonlinear systems with unknown inputs in the framework of convex optimization. We use an unknown input observer (UIO) to consider both nonlinearity and disturbance. By deriving a sufficient condition for exponential stability in the linear matrix inequality (LMI) form, existence of a stabilizing observer gain matrix of UIO will be assured by checking whether the quadratic stability margin of the error dynamics is greater than the Lipschitz constant or not. If quadratic stability margin is less than a Lipschitz constant, the coordinate transformation may be used to reduce the Lipschitz constant in the new coordinates. Furthermore, to reduce the maximum singular value of the observer gain matrix elements, an object function to minimize it will be optimally designed by modifying its magnitude so that amplification of sensor measurement noise is minimized via multi-objective optimization algorithm. The performance of UIO is compared to a nonlinear observer (Luenberger-like) with an application to a flexible joint robot system considering a change of load and disturbance. Finally, it is validated via simulations that the estimated angular position and velocity provide true values even in the presence of unknown inputs.