• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.571-577
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• 2012

In this paper, we design a flight controller using a dynamic compensator for a small unmanned aerial vehicle. The proposed method ensures flight stability during altitude holding and waypoints passing by improving the transient response and steady state error. The control system consists of dual feedback loops with an inner loop and a outer loop. The inner loop has a PD controller to improves the transient response and the outer loop has a dynamic compensator to reduce overshoot in the transient response and improve the steady state error. The performance of the proposed method is evaluated by flight test on a small UAV.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.129-132
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• 2002

The practical virtual compensator, which uses a dynamic multi-leaf collimator (dMLC) and three-dimensional radiation therapy planning (3D RTP) system, was designed. And the feasibility study of the virtual compensator was done to verify that the virtual compensator acts a role as the replacement of the physical compensator. Design procedure consists of three steps. The first step is to generate the isodose distributions from the 3D RTP system (Render Plan, Elekta). Then isodose line pattern was used as the compensator pattern. Pre-determined compensating ratio was applied to generate the fluence map for the compensator design. The second step is to generate the leaf sequence file with Ma's algorithm in the respect of optimum MU-efficiency. All the procedure was done with home-made software. The last step is the QA procedure which performs the comparison of the dose distributions which are produced from the irradiation with the virtual compensator and from the calculation by 3D RTP. In this study, a phantom was fabricated for the verification of properness of the designed compensator. It is consisted of the styrofoam part which mimics irregular shaped contour or the missing tissues and the mini water phantom. Inhomogeneous dose distribution due to the styrofoam missing tissue could be calculated with the RTP system. The film dosimetry in the phantom with and without the compensator showed significant improvement of the dose distributions. The virtual compensator designed in this study was proved to be a replacement of the physical compensator in the practical point of view.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.1066-1071
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• 1992

A new scheme of OFVSC(Output Feedvack Variable Structure Controller) is proposed for the servo control system. The main structure of proposed control scheme is composed of servo compensator and dynamic switiching function. By the use of dynamic switiching function the assumption of full state availability can be removed and the disturbances which does not satisfy the matching condition cna be rejected. And the servo compensator which is designed for each output variable the robustness for the all type of disturbances. And the performances of proposed control system are evaluated through simulation studies for a numerical example.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.539-545
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• 2001

This paper proposes a static synchronous series compensator based on multi-bridge inverter. The proposed system consists of 6 H-bridge modules per phase, which generate 13 pulses for each half period of power frequency. The dynamic characteristic was analyzed by simulations with EMTP code, assuming that it is inserted in the 154-kV transmission line of one-machine-infinite-bus power system. The feasibility of hardware implementation was verified through experimental works using a scaled model. The proposed system does not require a coupling transformer for voltage injection, and has flexibility in expanding the operation voltage by increasing the number of H-bridge modules.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.66-69
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• 2008

In this paper, The author present a load current feed-forward compensator by method that improve voltage controller of Step-down Chopper to get stable output voltage to sudden change of load current. To confirm the characteristicsof a presented load current feed -forward compensator compared each transfer function of whole system that load current feed-forward compensator is added with transfer function of whole system that existent voltage controller is included using Mason gains formula in Root locus and Bode diagram. As a result the pole of system is improved, extreme point of the wave and system improves, and size of peak value and phase margin of break frequency in resonance frequency confirmed that is good. Therefore, presented control technique could confirm that reduce influence by perturbation and improves stationary state and dynamic characteristics in output of Step-down Chopper.

• Proceedings of the KIEE Conference
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• 2007.11c
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• pp.108-111
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• 2007

A novel voltage sag compensator with hi-directional DC/DC converter of Electric double layer capacitor is proposed. Recently, the double-layer capacitor which is drawn attention as a new energy storage element has a lot of advantage such as no maintenance, long lifetime and quick charge/discharge characteristics with large current. This DC/DC converter is used to control the charging current to the double-layer capacitor and also used to keep the DC link voltage constant for discharge of the double-layer capacitor. Therefore, the proposed DC/DC converter has the high-efficiency controller, dynamic compensator of voltage sag is driven by this converter. Finally, experimental results show the validity of the control scheme and the ability of the dynamic voltage compensator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.503-509
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• 2014

In this paper, a PID controller with adaptive neural network compensator is proposed to control the formations of mobile robot. The control system is composed of a kinematic controller based on the leader-following robot and dynamic controller for considering the dynamics of the mobile robot. The dynamic controller is constituted by a PID controller and the adaptive neural network compensator for improving the performance and compensating the change in dynamic characteristics. Simulation results show the performance of the PID controller and the neural network compensator for the circular trajectory and linear trajectory. And it is verified that by improving the performance of a PID controller via the adaptive neural network compensator, the following robot's tracking performance is improved.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.7
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• pp.688-694
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• 2010

This paper presents a gravity compensator for the manipulator of a service robot. The manipulator of a service robot is operated with low velocity for the safety reason in most cases. In this situation gravitational torques generated by the mass of links are often much greater than dynamic torques for motion. A gravity compensator can counterbalance the gravitational torques, thereby enabling to utilize relatively low power motors. In this paper the gravity compensation for the roll-pitch rotation is considered which is often used for the shoulder joints of the manipulator of a service robot or humanoid robot. A gimbals is implemented and two 1-dof gravity compensators are equipped at the base. One compensates the gravitational torque at the roll joint and another provides the compensational torque for the gimbals. Various analyses showed that the proposed compensator can counterbalance the gravitational torques of 87% at the pitch joint and 50% at the roll joint. It is verified from dynamic simulations that the proposed compensator effectively counterbalances the gravitational torques.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.299-302
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• 1997

This paper describes a dynamic var compensator to compensate the line reactance for power transmission and distribution system. The compensator consists of a voltage source inverter with dc capacitor, coupling transformers, and control circuit. The operation of compensator was verified by computer simulations with EMPT and experimental works with a scaled hardware model. The advantage of the proposed system is rapid and continuous regulation of the reactive power.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.680-683
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• 1999

A thyristor controlled shunt compensator, which is installed in the middle of the transmission line is adopted for controlling real power flow in a simple power transmission system. By means on the Fourier series representation of the thyristor switching action and the system parameters, the thyristor current equations are derived, which transmit the required real power of the simple power transmission system and inform the thyristor firing angle, the thyristor conduction angle, the power flows and the harmonic characteristics EMTP simulations at the various operating points show the dynamic characteristics of the thyristor controlled shunt compensator and correspond to the results calculated with the Fourier series representation.