• International Journal of Control, Automation, and Systems
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• v.6 no.2
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• pp.234-242
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• 2008

The purpose of this paper is to verify the practical effectiveness of an interphalangeal coordination-based joint motion planning method for humanoid finger operations. For the purpose, several experiments have been performed and comparative experimental results are shown. Through the experimental works, it is confirmed that according to the employed joint motion planning method, the joint configurations for a finger's trajectory can be planned stably or not, and consequently the actual joint torque command for controlling the finger can be made moderately or not. Finally, this paper analyzes that the interphalangeal coordination-based joint motion planning method is practically useful for implementing a stable finger manipulation. It is remarkably noted that the torque pattern by the method is well-balanced. Therefore, it is expected that the control performance of humanoid or prosthetic fingers can be enhanced by the method.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.2
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• pp.207-216
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• 1991

In the case that the robot manipulator should respond to the variance and uncertainty of the environment in performing preforming precision tasks, it is indispensable that the robot utilizes the various sensors for intrlligence. In this paper, the robot force control method is implemented with a force/torque sensor, two personal computers, and a PUMA 560 manipulator for performing the various application tadks. The hybrid position/force control method is used to control the force and position axis separately. An interface board is designed to read the force/torque sensor output into the computer. Since the two computers should exchange the information quickly, a common memory board is designed. Before the algorithms of application tasks are developed, the basic force commands must be supplied. Thus, the MOVE-UNTIL command is used at the discrete time instant and, the MOVE-COMPLY is used at the continuous time instant for receiving the force feedback information. Using the two basic force commands, three application algorithms are developed and implemented for edge-following, insertion, and grinding tasks.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.340-345
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• 1998

A virtual reality system is implemented for the operator supervising a robot's operation at a remote site. For this implementation, a two D.O.F force-reflective joystick is designed to reflect the force/torque measured at the end of robotic manipulator and to generate the motion command for the robot by the operator using this joystick. In addition, the visual information that is captured by a CCD camera, is transmitted to the remote operator and is displayed on a CRT monitor. The operator who is holding the force reflective joystick and watching the CRT monitor can resolve unexpected problems that the robot confronts with. That is, the robot performs the tasks autonomously unless it confronts with unexpected events that can be resolved by only the operator. To demonstrate the feasibility of this system, a remote peg-in-hole operation is implemented and the experimental data are shown.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1410-1414
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• 1990

A method of speed sensorless vector control of induction motor is proposed in this paper. This method uses the slip frequency estimated by only the primary voltage and current. As this slip frequency accords with the command value of it, the commanded primary frequency is controlled. The validity of the method is confirmed by the simulation and experimental results.

• Journal of Electrical Engineering and information Science
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• v.1 no.2
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• pp.101-108
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• 1996

A new speed controller based on the fuzzy algorithm with hierarchical structure is presented. The input variables of the controller are speed error and its derivative(change of error), where the output variable is the change of torque current command. Several comparisons were performed with conventional PI (proportional plus integral) controller and proposed controller. These controllers are applied to the laboratory model drive system with 2.2kW induction motor. Some simulation and experimental results show that the speed controller using fuzzy algorithm is more robust than the conventional PI controller.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.10
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• pp.935-945
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• 2011

We study X-axis or Y-axis high agile attitude control method, using four reaction wheels and two control moment gyros. Since normal satellites use same actuators, researchers design an attitude controller first, and then allocate torque commands to each actuator. However, our satellite uses both control moment gyros and reaction wheels, whose torque output differences are very large. Therefore, we cannot apply normal attitude controller design procedure. In this paper, we solve this problem by combining actuator torque command and attitude controller. Through numerical simulations, we show that our method enables satellite high agility.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.266-273
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• 2003

A wind turbine simulator is developed for the emulation of variable input torque from the wind energy without actual rotor blades using motor-generator set. The torque command of dc motor is calculated from the characteristic equation of rotor blade during the change of wind speed. Especially the proposed control algorithm takes into account the fact that the moment of inertia of blade is much larger than that of driving motor. If you select the desired value of inertia, the stored/restored energy of the inertia during acceleration/deceleration can be compensated effectively resulting the only net torque is delivered to the generator. The simulator set-up has been designed and implemented using a do motor and drive. Feasibility of the proposed algorithm is verified by computer simulations and experiments.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.585-586
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• 2010

An induction motor operated with a conventional direct self controller(DSC) shows a sluggish response during startup and under changes of torque command. Fuzzy logic controller(FLC) is used in conjunction with DSC to minimize these problems. A FLC chooses the switching states based on a set of fuzzy variables. Flux position, error in flux magnitude and error in torque are used as fuzzy state variables. Fuzzy rules are determinated by observing the vector diagram of flux and currents. This paper proposes hybrid FLC for direct torque control(DTC) of induction motor drives. This controller is controlled speed using hybrid FLC. The performance of the proposed induction motor drive with hybrid FLC is verified by analysis results at various operation conditions.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.5
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• pp.361-368
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• 2010

This paper presents high speed position controller using stepping motor. The proposed position controller has close loop and open loop mode. In the high speed region, torque angle which is controlled by PI controller and memory based look-up table, is used to keep the reference position. The memory based look-up table produces a torque angle according to motor speed, and the PI controller can compensate the torque angle error. So, the fast dynamic response can be expected in the same position error. The open loop control mode which is divided by 3-modes control the actual position in the low speed and small position error. Each open loop modes are designed to reduce position error and dynamic brake in the stop command. The proposed position control scheme is verified by the practical stepping motor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.11
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• pp.934-943
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• 2018

In these days, demand for agile spacecraft is gradually increasing, due to the fact that agile spacecraft can improve mission capability. In this paper, an attitude control logic based on reaction wheels that can enhance agility of spacecraft is proposed. Three methods are suggested, and all three or part of them can be integrated to the existing attitude control system. First, a feedforward/feedback controller is introduced, and its pros and cons are provided, compared to the conventional feedback controller. Second, an attitude command generation method that fully utilizes torque/momentum capacities of reaction wheels is proposed. Third, a torque (current) control mode for internal wheel control is introduced. Numerical results verify that the settling time can be significantly reduced by employing the feedforward/feedback control method, especially for large angle maneuver.