• Journal of the Korean Society of Industry Convergence
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• v.3 no.2
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• pp.115-121
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• 2000

This paper presents reducing method of profile error on a mechanical tuning for multi-spindle control of NC machine tools. To reduce the profile error in the feed drive system, it is useful to adopt same transfer function of multi spindle machine tools. By selecting the correction vector of servo rigidity and natural vibration on JK map, multi spindle control can be tuned by mechanical parameters with small profile error.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.6
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• pp.524-532
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• 2002

This paper presents a new in-flight alignment method for an SDINS under large initial heading error. To handle large heading error, a new attitude error model is introduced. The attitude errors are divided into heading error and leveling errors using a newly defined horizontal frame. Some navigation error dynamic models are derived from the attitude error model for indirect feedback filtering of the in-flight alignment system. A Kalman filter with Position measurement is designed to estimate navigation errors as the indirect feedback filter Simulation results show that the proposed in-flight alignment method reduces the heading error very quickly from more than 40deg to about 5deg so as to apply a refined navigation filter. The total alignment process including leveling mode and navigation mode in addition to the proposed one allows large initial values not only in heading error but also in leveling errors.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.470-475
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• 2002

Instantaneous following PWM control technique is pulsed nonlinear dynamic control method. This new control technique using analog integrator is proposed to control the duty ratio D of do-dc converter. In this control method, the duty ratio of a switch is exactly equal In or proportional to the control reference in the steady state or in a transient. Proposed control method compensates power source perturbation in one switching cycle, and the average value of the dynamic reference in one switching cycle. There is no steady state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with buck converter have demonstrated the robustness of the control method and verified theoretical prediction. The control method is very general and applicable to all type PWM

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.3
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• pp.613-621
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• 2016

Since the error control problem is a critical and sensitive issue in the one-way network, we can adopt a forward error correction code method or data retransmission method based on the response of reception result. In this paper, we propose error control method and continuous data transmission protocol in the one-way network which has unidirectional data transmission channel and special channel to receive only the response of reception result. Furthermore we present data encryption and key update mechanism which is based on the pre-shared key distribution scheme and suggest some ASDU(Application Service Data Unit) formats to implement it in the one-way network.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.168-175
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• 2011

Contouring accuracy of CNC machine tools is very important for high-speed and high-precision machining. In particular, large contour error may occur during corner tracking. In order to reduce the corner contouring error, acceleration and deceleration control or tool-path planning methods have been suggested. However, they do not directly control the corner contouring error. In the meantime, network servo systems are widely used because of their easiness of building and cost effectiveness. Communication latency between the master controller and servo drives, however, may deteriorate contouring accuracy especially during corner tracking. This paper proposes a control strategy that can accurately calculate and directly control the corner contouring error. A prediction control is combined with the above control to cope with communication latency. The proposed control method is evaluated through computer simulation and experiments. The results show its validity and usefulness.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.190-200
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• 1996

Step-by-step time integration methods are widely used for solving structural dynamics problem. One difficult yet critical choice an analyst must make is to decide an appropriate time step size. The choice of time step size has a significant effect on solution accuracy and computational expense. The objective of this research is to derive error estimate for newly developed time integration method and develop automatic time step size control algorithm for structural dynamics. A formula for computing error tolerance is derived based on desired period resolution. An automatic time step size control strategy is proposed based on a normalized local error estimate for the generalized-α method. Numerical examples demonstrate the developed strategy satisfies general design criteria for time step size control algorithm for dynamic problem.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.160-163
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• 2005

This paper proposes a simple MPPT control scheme of a Current-Control-Loop Error system Based that can be obtains a lot of advantage to compare with another digital control method, P&O and IncCond algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. Therefore, it is applied a small home power generation system that required many expenses. But, a proposed method is easy to solve the cost reduction and power unbalance problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment on battery charger using PIC that is the microprocessor of a low price.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.12
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• pp.994-1000
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• 2003

A new relative motion control methodology for a following system to an independent leading system is proposed for controlling relative position, velocity, and tension etc. It is based on maintaining minimum relative error between two independent systems. The control command of the following system to a leading system is generated by adding the current command and the output of the relative error compensation. The proposed control method is implemented on the experimental equipment which is a wire winding-unwinding system to control the tension of the line. The results show the unwinding system(follower) following the independent motion of the winding system(leader) to control the constant tension of the line in order to keep the roller dancer in reference position. The relative motion control method proposed in this paper can be applied to high precision equipment for unwinding and winding fine wire, fine fiber, and tape etc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.103-105
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• 2002

Instantaneous following PWM control technique is pulsed nonlinear dynamic control method. This new control technique using analog integrator is proposed to control the duty ratio D of Cuk converter. In this control method, the duty ratio of a switch is exactly equal to or proportional to the control reference in the steady state or in a transient. Proposed control method compensates power source perturbation in one switching cycle, and the average value of the dynamic reference in one switching cycle. There is no steady state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with Cuk converter have demonstrated the robustness of the control method and verified theoretical prediction. The control method is very general and applicable to all type PWM.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.10
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• pp.962-967
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• 2006

Indoor positioning is highlighted recently, and various kinds of indoor positioning systems are under developments. Since positioning systems have their own characteristics, proper positioning scheme should be chosen according to the required specifications. Positioning methods are classified into time-based and angle-based one. This paper presents the error analysis of time-based and angle-based location methods. Because measurements of these methods are nonlinear, linearizations are needed in both cases to estimate the user position. In the linearization, Gauss-Newton method is used in both cases. To analyze the position error, we investigate the error ellipse parameters that include eccentricity, rotation angle, and the size of ellipse. Simulation results show that the major axes of TOA and AOA method lie in different quadrants at most region of workspace, especially where the geometry is poor. When the TOA/AOA hybrid is employed, it is found that the error ellipse is reduced to the intersection of ellipses of TOA and AOA.