• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.597-600
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• 1997

In this paper, the authors propose a new method for linearizing a nonlinear dynamical system by use of polynomial compensation. In this method, an M-sequence is applied to the nonlinear system and the crosscorrelation function between the input and the output gives us every crosssections of Volterra kernels of the nonlinear system up to 3rd order. We construct a polynomial compensation function from comparison between lst order Volterra kernel and high order kernels. The polynomial compensation function is, in this case, of third order whose coefficients are variable depending on the amplitude of the input signal. Once we can get compensation function of nonlinear system, we can construct a linearization scheme of the nonlinear system. That is. the effect of second and third order Volterra kernels are subtracted from the output, thus we obtain a sort of linearized output. The authors applied this method to a saturation-type nonlinear system by simulation, and the results show good agreement with the theoretical considerations.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1401-1404
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• 2008

Temperature Compensation Method of Local Dimming LED Backlight System is proposed. The luminance levels of the LED backlight are not stable over temperature and time due to the inherent characteristics of the LED. The characteristics of LED backlight are investigated and a temperature compensation method is presented. The image distortion caused by temperature variation of LED block can be effectively compensated by the proposed temperature compensation method.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.158-164
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• 1994

A volumetric error compensation method was stueide with measuring systematic error of a Coordinate Measuring Machine(CMM). The volumetric error equations were proposed for a Moving Bridge type CMM. Using the error equations, error vectors in the measuring volume were corrected by a software method. The CMM was controlled by the compensation program separately in the measuring and moving function of the CMM proving. The linear accuracy of the CMM was measured by the Laser Interferometer and compared with the data before the volumetric error compensation. This method was proved as low cost and effective to reduce the systematic error of the CMM, as no hardware modification is required.

• Journal of Mechanical Science and Technology
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• v.20 no.1
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• pp.51-58
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• 2006

To compensate for the motion errors in hydrostatic tables, a method to actively control the clearance of a bearing corresponding to the amount of error using actively controlled capillaries is introduced in this paper. The design method for an actively controlled capillary that considers the output rate of a piezo actuator and the amount of error that must be corrected is described. The basic characteristics of such a system were tested, such as the maximum controllable range of the error, micro-step response, and available dynamic bandwidth when the capillary was installed in a hydrostatic table. The tests demonstrated that the maximum controllable range was $2.4\;{\mu}m$, the resolution was 27 nm, and the frequency bandwidth was 5.5 Hz. Simultaneous compensation of the linear and angular motion errors using two actively controlled capillaries was also performed for a hydrostatic table driven by a ballscrew and a DC servomotor. An iterative compensation method was applied to improve the compensation characteristics. Experimental results showed that the linear and angular motion errors were improved to $0.12{\mu}m$ and 0.20 arcsec, which were about $1/15^{th}$ and $1/6^{th}$ of the initial motion errors, respectively. These results confirmed that the proposed compensation method improves the motion accuracy of hydrostatic tables very effectively.

• Journal of Sensor Science and Technology
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• v.28 no.5
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• pp.334-339
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• 2019

In this study, we propose a compensation method of raw LiDAR data with noise and noise filtering for signal processing of LiDAR sensors during the development phase. The raw LiDAR data include constant errors generated by delays in transmitting and receiving signals, which can be resolved by LiDAR signal compensation. The signal compensation consists of two stage. First one is LiDAR sensor calibration for a compensation of geometric distortion. Second is walk error compensation. LiDAR data also include fluctuation and outlier noise, the latter of which is removed by data filtering. In this study, we compensate for the fluctuation by using the Kalman filter method, and we remove the outlier noise by applying a Gaussian weight function.

• Journal of IKEEE
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• v.16 no.1
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• pp.34-44
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• 2012

This paper proposes a practical compensation method by using digital signal processing over the creep error which is representative in strain gauge loadcell. The signal compensation method carry out the simulation by deciding compensation constant (time constant) and coefficient measuring the loadcell output response. Then, compensation constant and coefficient are stored on the microprocessor. By using calculated on microprocessor creep error compensation values, weighting value is showed as a digital signal by reducing error values measured through output signals of loadcell. In addition, we apply error compensation method in order to have a dedicated software for loadcell electronic scale. This technique is useful because it has great influence on error rate reduction that has been produced by conventional electronic scales (0.03%). As a result our technique gives better accuracy (0.01%~0.003%) as what is given by digital electronic scale, while it has less complex operation processing.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.76.3-76
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• 2001

In this paper, an adaptive disturbance compensation technique is used in a tracking problem, under which the tracking reference is unknown. Based on a simple disturbance observer that effectively estimates the low frequency components of disturbance, the feedforward compensation is applied in addition to the conventional feedback control. Under the proposed compensation method, sensitivity analysis is given to illustrate the effectiveness. Finally, the proposed method is applied to the tracking problem in an optical storage system.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.164-167
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• 2001

In resent years, electric power quality has become an important issue in power system. Voltage variation and compensation countermeasures of KEPCO system in west Gyeongnam have been simulated using PSS/E. In this paper, in the abnormal power system, the adaption of SVC, high speed and continuous control are simulated for voltage compensation. It is shown that the SVC is the optimal voltage compensation method in loop power system or 2 lines radial system.

• 전기의세계
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• v.28 no.12
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• pp.41-45
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• 1979

Improvement of power factor is achieved by reactive-current compensation, connecting power condenser to the circuit. This paper describes a method of reactive-current compensation, employing thyristor switching of capacitor banks without any breaker. This method reduces supply transients to the minimum by means of connecting condenser, because thyristor is triggered at zero point in condenser current. The reactive current detection and the experimental system to trigger thyristor at appropriate moment are given. IThe results show the fast reactive-current compensation on the condition of minimum transient.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.196-199
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• 2001

This paper deals with current harmonics and unbalanced source voltages compensation using combined filter system. Filter system consists of a series active filter and parallel passive filters. Passive filters were a traditional method to compensate current harmonics, so those were installed in power system widely. The active filter can be a substitution to improve filtering characteristics and complement drawbacks of the passive filter. The combined system of the active power filter and passive filter can has a better compensation performances and economical goods. The series type active power filter injects compensation voltage into power system by transformers. It's compensation principle is able to applicate for voltage compensation. A new control algorithm for series active filter to compensate current harmonics and unbalanced source voltages is proposed. In the proposed algorithm, a compensation voltage for harmonic reduction is calculated directly by instantaneous reactive power theory, and a compensation voltage for unbalanced source voltage is calculated in based on a synchronous reference frame. By experiments, we show validity of proposed compensation method.