• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.189-194
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• 1994

Adaptive control systems based upon the command generator tracker(CGT) approach have attracted considerable interest because of the simple structure of its adaptive controller. Some attempts to such improve the adaptive control algorithm, for the sake of the application to broader class of plants, are made. Recently, Su and Sobel(1992) proposed that those schemes can be treated by an unified theory using a metasystem representation with some types of supplementary dynamics. However, in their method, it is difficult to find the dynamic compensator, which is proper and output feedback stabilizable, for the uncertain plant. This paper proposes a new design method of such supplementary dynamics and some parameters of adaptive control system for linear time invariant SISO plants. The method gives a concrete and systematic design method using only a few priori knowledge of the plant.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.8
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• pp.831-838
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• 2009

This paper proposes an IR (infrared) LED (Light Emitting Diode)-based tactile fingertip sensor that can independently measure the normal and tangential force between the hand and an object. The proposed IR LED-based tactile sensor has several advantages over other technologies, including a low price, small size, and good sensitivity. The design of the first prototype is described and some experiments are conducted to show output characteristics of the proposed sensor. Furthemore, the effectiveness of the proposed sensor is demonstrated through anti-slip control in a multifunction myoelectric hand, called the KNU Hand, which includes several novel mechanisms for improved grasping capabilities. The experimental results show that slippage was avoided by simple force control using feedback on the normal and tangential force from the proposed sensor. Thus, grasping force control was achieved without any slippage or damage to the object.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.60-66
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• 2012

This paper aims to constitute a feedback vibration control system using wireless sensor networks and experiment it on a model structure to verify its effectiveness. For the purpose, we set up a feedback vibration control system composed of a wireless input/output(I/O) sensor node based on bluetooth, a home-made shear type MR damper, a shaker which generates a constant size of sine wave, and a simple beam model structure. The vibration control experiment was performed by shaking the 1/4 point of beam with a shaker. At the moment of shaking, we controled the vibration with MR damper which was placed vertically on the center of beam. Simultaneously, by acquiring acceleration response at the 2/4 point of beam, we evaluated the effectiveness of control capability. The control command was set to send a voltage signal to MR damper when the acceleration response, acquired from the wireless I/O sensor node placed at the center of beam, was more than a certain amount. Although the realtime feedback vibration control system constituted in this paper is effective only within a limited command system, it has been proven that the system was able to effectively decrease the vibration of structure by generating a control command aimed for realtime purpose. The system also showed a possibility to be used as a structural response control system adapting a variety of semi-active control algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.3
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• pp.29-41
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• 1992

According to the recent increase of demands for multi-function and economics on hydraulic excavator, it is required that excavator should have simple operation, higher and operational efficiency, however the modeling of engine/pump system of excavator is not prescribed by the paper. So, in this paper the modeling of engine/pump system of excavator is suggested by identification method from step response and verified effectiveness of identification system by comparing with experimental results which was conducted using PID controller. To improve the problem of parameter variation and modeling error in the system, sliding mode control was introduced and new switching surface was designed. This control algorithm was applied to a hydraulic excavator by simulation, and its effectiveness was verified, and the results of variable structure system for the excavator system using a output component was compared with that of full state feedback when load disturbances and system paramenter variation exist.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_1
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• pp.889-896
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• 2020

We describe a new approach to the analyze the control performance of robotic manipulator based on the monitoring system. The structure of monitoring simulator is consist of seven modes such as control state mode, coordinate mode, input/output mode, program mode, parameters mode, and track mode. The applied control algorithme consists of an time varying feed-forward and feedback controller. The proposed scheme is simple in structure, fast in computation, and suitable for real-time implimemtation. Moreover, this scheme does not require any accurate dynamic modeling and values of parameters. Performance of the proposed monitoring system is illustrated by simulation and experiment for robot manipulator with six degrees of freedom.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.7
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• pp.1-8
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• 2004

A simple AMC (Adaptive Modulation and Coding) technique using ARQ (Automatic Repeat Request) for a MIMO (Multiple Input Multiple Output) system is proposed which does not require the additional feedback. In addition, the proposed AMC technique is different from the conventional technique in the aspect of considering the MCS (Modulation and Coding Scheme) level from the previous packet. The proposed technique can discard fewer amounts of unsuitable packets than the conventional technique. In the proposed system not only same rate control method for transmit antennas but also individual rate control method can be applied. The performance of the proposed technique is verified under a MIMO-OFDM (Orthogonal Frequency Division Multiplexing) system based on WLAN (Wireless Local Area Network), IEEE 802.11a. The results of the computer simulation show that a MIMO system with the proposed technique achieves higher throughput than one with a fixed transmission rate.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.103-108
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• 2007

Neural network is used in many fields of control systems currently. However, It is not easy to obtain input-output pattern when neural network is used for the system of a single feedback controller and it is difficult to get satisfied performance with neural network when load changes rapidly or disturbance is applied. To resolve these problems, this paper proposes a new mode to implement a neural network controller by installing a real object in place of activation function of Neural Network output node. As the Neural Network self adaptive control system is designed in simple structure neural network input-output pattern problem is solved naturally and real tin Loaming becomes possible through general back propagation algorithm. The effect of the proposed Neural Network self adaptive control algorithm was verified in a test of controlling the speed of a A.C. servo motor equipped with a high speed computing capable DSP (TMS320C32) on which the proposed algorithm was loaded.

• ETRI Journal
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• v.20 no.1
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• pp.28-36
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• 1998

A simple experimental method to design gain-flattened erbium-doped fiber amplifier is proposed and demonstrated based on the two linear relations between the output power and the pump power, and between the gain and the length of the eribium-doped fiber at the gain flattened state. The spectral gain variation of the eribium-doped fiber amplifiber constructed by this method was less than 0.4 dB over 12 nm (1,545~1,557nm) wavelength region. The gain flatness is also controlled within 0.4 dB over the input power range of -30~-15dBm/ch through the feedback control utilizing the amplified spontaneous emission power in the 1,530 nm region.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.582-587
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• 1987

In this paper, a controller design method for the DC motor driving system is described emphasizing the specified degree of accuracy undergoing large time varying disturbances, coulomb friction and arm-load resonance. A feedforward compensation technique using the current controller is proposed, and resulting in the performance improvement as well as the implementational simplicity. A time-weighted quadratic performance index is used in the optimization of the controller, which is a salient way of obtaining better closed-loop performance in a simple manner. Computer simulations are also given to show the usefulness of the proposed techniques.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.948-951
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• 1996

High-speed/high-accuracy control of robot manipulator becomes more and more stringent because of the external disturbance and nonlinear characteristics. To meet this ends, lots of control strategies were proposed in the past such as the computed torque control, the nonlinear decoupled feedback control, and adaptive control. These control methods need computations of the inverse dynamics and require much computational effort. Recently, a disturbance observer with unmodeled robot dynamics and simple algorithms to motion control have been widely studied. This paper proposes a motor control strategy based on the disturbance observer which estimate the disturbance of each joint from input-output relationship of the actuator and eliminate the estimated disturbance including the torque due to modeling errors, coupling force, nonlinear friction, and so on. To apply the disturbance observer to closedloop system like velocity servo pack, the modified control structure was constructed and shown that it is equivalent to a disturbance observer in open-loop system. Finally, using the proposed approach, simulation and experiments were carried out for a two-degree-of-freedom SCARA type direct drive robot, and show some results to verify the effectiveness of the proposed algorithms.