• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.270-273
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• 2002

복수구동장치를 사용하여 작업을 수행하는 시스템은 동기화를 위해 기계적인 제한조건을 두고 운용하는 경우 지속적인 유지보수가 요구되고 작업 정밀도가 떨어진다 이러한 단점을 보완하기 위해 개별적인 구동장치의 제어루프 외부에 동기화를 위한 제어루프를 추가하는 방법이 제안되었다. 본 논문에서는 CAN(Controller Area Network)으로 연결된 두 대의 서보앰프를 구동하여 주어진 작업을 수행하는 경우 외란과 내부 파라미터 변동에 강인한 $H^{\infty}$ 제어기를 설계하고 이를 이용하여 동기제어 알고리즘을 구현하고자한다.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.323-326
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• 2003

본 논문에서는 PID 제어기를 이용해 외란제거를 함은 물론 최적 제어가 될 수 있는 파라메터를 유전자 알고리즘을 통해 구하는 방법을 제안하였다. 외란제거를 위해 $H_\infty$-norm을 응용하여 제어시스템의 외란 제거 조건들을 제시하고 이 조건들을 만족하는 PID 제어기를 설계하였다. 설계된 PID제어기의 최적 파라메터를 구하기 위해 유전자 알고리즘을 이용하였고 최적 파라메터를 평가하기 위하여 ITSE(Integral of time weighted squared error)성능지수를 이용하였다. 위의 설계 기법들을 서보모터의 제어에 적용하여 만족할 만한 결과를 얻었다.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.6
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• pp.524-530
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement and skeletal muscle contract. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for- stimulation with horizontal, vortical and 3D patterns. The Off-vortical axis rotator is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1135-1141
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• 2004

In this study, this system makes use of the analog infrared rays sensor and converts the feature of fish outline when sensor is operating with CPU(80C196KC). Then, after signal processing, this feature is classified a special feature and a outline of fish by using the neural network, one of the artificial intelligence scheme. This neural network classifies fish pattern of very simple and short calculation. This has linear activation function and the error back propagation is used as a teaming algorithm. And the neural network is learned in off-line process. Because an adaptation period of neural network is too long when random initial weights are used, off-line teaming is induced to decrease the progress time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.161-164
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• 2008

A realization for EMG signal sensing and vertical control system of robotizing arm is presented in this paper. The system is realized that a fine EMG bio-signals of humans' arm muscle are detected by surface electrode sensor, making a high performance amplifier and filtering, converting analog into digital signal and driving a servomotor for robotizing arm. The system is experimented by monitoring multiple step vertical control angles of robotizing arm corresponding to EMG signals in moving arm muscles. The experimental result are that the vertical control level is measured to around 2 degrees and mean error is 5% approximately.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.92-101
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• 2010

Recently, the magnetic bearings which have many advantages such as no noise, less mechanical friction are widely applied to the suspension of rotors on the rotary machineries. However, the magnetic bearing system is inherently unstable, nonlinear and MIMO(multi-input-multi-output) system as well. In this paper, we design a state feedback controller using linear matrix inequality(LMI) to the multi-objective synthesis, for the magnetic bearing system with integral type servo system. The design objectives include $H_{\infty}$ performance, asymptotic disturbance rejection, and time-domain constraints on the closed-loop pole location. The results of computer simulation show the validity of the designed controller.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.5
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• pp.1-7
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• 1997

In this paper, a neuro-contouring control scheme for the high precision machining of CNC machine tools is descrihed. The proposed control system consists of a conventional controller for each axis and an additional neuro-controller. For contouring control, the contour error must be computed during realtime motion, but generally the contour error for nonlinear contours is difficult to he directly computed. We, therefore, propose a new contour error model to approximate real error more exactly, and here we also introduce a cost function for better contouring performance and derive a learning law to adjust the weights of the neuro-controller. The derived learning law guarantees good contouring performance. Usefulness of the proposed control scheme is demonstrated hy computer simulations.

• Journal of Navigation and Port Research
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• v.31 no.1 s.117
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• pp.55-64
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• 2007

In general mechanical servo systems, friction deteriorates the performance of controllers by its nonlinear characteristics. Especially, friction phenomenon causes steady-state tracking errors and limit cycles in position and velocity control systems, even though gains of controllers are tuned well in linear system model. Even if sensor is used higher accuracy level, it is difficult to improve tracking performance of the position to the same level with a general control method such as PID type. Therefore, many friction models were proposed and compensation methods have been researched actively. In this paper, we consider that the variation of mover's mass is various by loading and unloading. The normal force variation occurs by it and other parameters. Therefore, the proposed control system is composed of main position controller and a friction compensator. A parameter estimator for a nonlinear friction model is designed by adaptive control law and adaptive backstepping control method.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.6
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• pp.484-491
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• 2005

Using a disturbance observer is effective in enhancing the performance of dynamic system in presence of disturbances. Although various types of disturbance observers have been proposed to improve sensitivity of systems, there exist poor transient responses due to cross-couplings among disturbance observer loops. In this paper, dual disturbance observer (DOB) is proposed to reduce the effects of the cross-couplings. A different type of loop transfer function is proposed for external disturbance observer. While improving the sensitivity function by adding external DOB, it also provides improved complementary sensitivity function. The proposed dual DOB is applied to a commercial optical disk drive tracking system. It is shown that the dual DOB is an effective method in rejecting the effect of disturbance as well as improving the tracking performance.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.1
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• pp.47-53
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• 1999

CD-ROM(Compact Disk-Read Only Memory) is very attractive storage media because it has much storage space but is small size and portable. Optical pickup, one of the most important parts for reading data on a CD-ROM, is not produced tuned up. For the use of goods, we must tune up the optical pickup by adjusting the screw for adjustment. First, we developed analog servo system for optical pickup tuners. For eliminating some problems in analog servo system, this paper designed the modeling of digital servo system for optical pickup tuner. Though the characteristics of optical pickup are changed, the digital servo system for optical pickup tuner can easily apply to all pickup, and can reduce the measurement error among the optical pickup tuners. For the purpose of confirming the designed digital servo system, we produced data that specify the disk vibration and the disk eccentricity, and simulated servo system with MATLAB.