• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.86-89
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• 1992

One of the most difficult problems in depth control for underwater vehicle is the effect of seaway disturbance. One component of the seaway forces is of large magnitude with a relatively narrow-band, first order component. The other component is generaly of somewhat smaller magnitude, second order component. Since the magnitude of the first order component is generally much greater than the compensating force that can be generating by the planes, it is undesirable for the controller to generate a control command. In this paper, we disigned adaptive notch filtering system using filter bank structure. Energies of each band-passed signal are obtained by MA(Moving Average) method and compared to produce center frequency. By adapting this parameter to notch filter, 1st order seaway disturbance can be removed, which lead to the improvement of automatic depth control system.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.2
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• pp.61-68
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• 2005

This paper is concerned with attitude control of 2 rotor 1 DOF aerial vehicle. The proposed controller consists of two parts: the attitude estimation filter part and PID controller part. For attitude estimation, performance of 3 different filters (complementary filters, Kalman filter, indirect Kalman filters) are tested and compared. For the PID controller, characteristic ratio assignment methods are used to assign PID coefficients. Through experiments, it is shown that attitude of the vehicle successfully follows the step command.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2067-2069
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• 1998

A prototype semiconductor switch for the command resonant charging system has been developed for a line type modulator, which charges parallel pulse forming network(PFN) up to voltage of 5 kV at repetition rates of 60 Hz. A phase controlled power supply provides charging of the 4.7 ${\mu}s$ filter capacitor bank to voltage up to 5 kV. A solid state module of series stack array of sixe matched SCRs(1.6 kV, 50 A) is used as a command charging switch to initiate the resonant charging cycle. Both resistive and RC snubber network are used across each stage of the switch assembly in order to ensure proper voltage division during both steady state and transient condition. A master trigger signal is generated to trigger circuits which are transmitted through pulse transformer to each of the 6 series switch stages. A pulse transformer is required for high voltage trigger or power isolation. This paper will discuss trigger method, protection scheme, circuit simulation, and test result.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.105-112
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• 2002

In this paper, a servo filter design for the gimbal engine actuator system of KSR-III(Korea Sounding Rocket-III) is considered. A reasonable filter structure is determined based on the actuator analytic models. The servo filter consists of a 2-nd order lowpass filter and a 1-st order compensator. The lowpass filter is required to protect the actuator from high frequency vibration, and the compensator to enhance the resulting stability. A Butterworth type servo filter is considered as the simplest one. The final servo filter type is determined by evaluating simultaneously both high frequency gain reduction performance and the corresponding KSR-III stability margin. Consequently it is revealed that a notch type servo filter located on the error between command signal and feedback signal in the control loop is very effective. Later, based on the proposed servo filter type, an onboard servo filter hardware of KSR-III will be designed and tested.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.5
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• pp.623-629
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• 2018

The acceleration and the angular velocity that include natural frequencies of a missile detected by Inertial Measurement Unit(IMU) are transmitted to the control loop of a missile. The control loop command that is calculated using above signals can cause the resonance of the missile while it flies. Hence it is common to adapt the filter and the control loop for attenuating or eliminating the undesired signals such as natural frequencies. This paper introduces the new test technique using a floating system for performance evaluation of the designed filter and the control loop prior to a flight test. The proposed scheme can check out the degradation property of vibration in the filter and the control loop, while the conventional hardware-in-the-loop simulation(HILS) scheme cannot.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.417-420
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• 2000

In order to the torque control the indirect flux control was performed by controlling the ratio of e/f and the q-axis flux was estimated by the slip command and q-axis flux was estimated by the slip command and q-axis current in the rotor circuits. Also the frequency was controlled to keep on the q-axis flux to be zero and the constant torque characteristics could be obtained by generation the preset torque. In the induction motor driven by the boltage source inverter with the constant voltage and frequency the speed variation is expressed as a slip So the speed control can be achieved by slip compensation The slip was calculated with a q-flux current filtered by first-order filter and as the result the error problem which may occur in current detection was eliminated

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.3
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• pp.259-265
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• 2012

This paper introduces a method for design and implementation of a current controller for boost converter operating in continuous conduction mode (CCM) using a digital signal processor (DSP). A Proportional-Integral (PI) type current controller outputs an average voltage command for inductor, used in the input side of the boost converter, and the duty-ratio of PWM (pulse width modulation) signal for switching device is directly calculated from the average voltage command. The gains of the PI current controller are selected such that the current response characteristics are the same as those of a first-order low-pass filter. The proposed current control scheme is implemented using a DSP based on fixed-point math operations and an experimental study has been performed to validate the proposed method.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.357-363
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• 2005

The non-minimum phase characteristic of a flexible manipulator makes tracking control of its tip difficult. The level of the tip tracking performance of a flexible manipulator is significantly affected by the characteristics of the tip reference trajectory as well as the characteristics of the flexible manipulator system. This paper addresses the question of how to best specify a reference trajectory for the tip of a flexible manipulator to follow in order to achieve the objectives of reducing : tip tracking error, residual tip vibration, and the required actuation effort at the manipulator joint. A novel method of tip-based learning controller for the flexible manipulator system is proposed in the paper, where a model of the flexible manipulator system with a command shaping filter is used to generate a smooth and realizable tip reference trajectory for a tip-based learning controller.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.287-292
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• 1998

This paper presents some results of performance evaluation test via actual machines of a new hybrid vector control utilizing a new indirect orientation scheme and stable filter embedded direct orientation scheme for induction motors without speed or position sensor. It is shown through the test by 0.3(kW) and 3.7(kW) motors that the proposed sensorless vector control has the following high potentialities: 1) speed range is 0 to 600(rad/s) or more, 2) zero-speed command is accepted and settles the machines at a stable standstill with no vibration 3) it can make machines to track variable command of acceleration and deceleration $\pm$6,000(rad/s2), 4) it can make machines to drive directly load of at least 26 times larger inertia than that of the machine, 5) it can make machines to produce much larger torque than the rating in torque control mode even at standstill. The performance confirmed by the test is far away for previous schemes or sensorless drive apparatuses.

• Journal of Power Electronics
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• v.11 no.2
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• pp.140-147
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• 2011

In this paper, a novel position controller based on state feedback and feed-forward is proposed. Traditional position and speed controllers are replaced by a single controller with the position and speed as state feedbacks, and the position command and load torque as feed-forwards. The feedback and feed-forward gains are obtained by analytic modeling and design. The load torque, rotor speed and position are estimated by an observer based on a Kalman filter (KF) with a low resolution mechanical position sensor. Feed-forward compensation by an estimated load torque is used to improve the dynamic performance during load torque changes.