List of English Publication

@inproceedings{ParkShimKong16,

title = {Can Continuous-time Disturbance be Represented by Sampled Input Disturbance?},

author = {Gyunghoon Park and Hyungbo Shim and Kyungchul Kong},

doi = {10.1109/ICCAS.2016.7832474},

year  = {2016},

date = {2016-10-19},

booktitle = {Proc. of 2016 16th International Conference on Control, Automation and Systems},

pages = {1261-1266},

publisher = {IEEE},

address = {Gyeongju, Korea},

abstract = {Abstract:

In this paper, we study whether any continuous-time disturbance to a continuous-time plant can be equivalently represented by a sampled input disturbance to a sampled-data model. With the help of the sampled-data system theory, we show that such equivalent sampled disturbance exists for almost sampling period and even for mismatched continous-time disturbances. Moreover, it is also discussed that whether the equivalent sampled disturbance is bounded significantly depends on the zeros of the sampled-data system. Simulation results verify the validity of the stability analysis.},

keywords = {Continuous-time system, Sampled data system, Stability},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{YunChangShimSeo15,

title = {A Preliminary Result on Frequency-shaped Model Predictive Control},

author = {Hyeonjun Yun and H. J. Chang and Hyungbo Shim and Jin Heon Seo},

doi = {10.1109/CDC.2015.7402566},

year  = {2015},

date = {2015-12-15},

booktitle = {Proc. of 2015 IEEE 54th Conference on Decision and Control},

journal = {Proc. of 2015 IEEE 54th Conference on Decision and Control},

pages = {2395-2399},

publisher = {OEEE},

address = {Osaka, Japan},

abstract = {This paper introduces frequency-shaped model predictive control (FSMPC) by considering the cost function in the frequency domain, which applies for discrete-time linear systems. Borrowing from the idea of using Parseval's theorem in the technique of the frequency-shaped LQR, we show that FSMPC can be formulated as a standard form of MPC. The terminal cost of the proposed FSMPC is chosen such that, when there are no state/input constraints, the optimal cost of FSMPC becomes the same as that of the frequency-shaped LQR, from which two benefits are obtained. That is, the closed-loop stability is straightforwardly achieved, and the performance of frequency-shaped LQR is inherited while state/input constraints are taken into account. A few examples are included to illustrate the effectiveness of the proposed FSMPC.},

keywords = {Stability},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{HanKimJooJoSeo13,

title = {A Simple Noise Reduction Disturbance Observer and Q-filter Design for Internal Stability},

author = {Jerome Han and Hongkeun Kim and Youngjun Joo and Nam Hoon Jo and Jin Heon Seo},

doi = {10.1109/ICCAS.2013.6704014},

year  = {2013},

date = {2013-10-20},

booktitle = {Proc. of 13th International Conference on Control, Automation and Systems (ICCAS 2013)},

pages = {755-760},

publisher = {IEEE},

address = {Gwangju, South Korea},

abstract = {The noise reduction disturbance observer is an unconventional construction of disturbance observer which has the ability of attenuating the high frequency measurement noise as well as the low frequency input disturbance. While retaining the same capabilities, this paper explores a more concise and prevailing version of the noise reduction disturbance observer with a more relaxed almost necessary and sufficient condition for the closed-loop system to be internally stable without requiring the stability of the nominal plant. Moreover, the proposed version is reduced-order compared with the classical disturbance observers in the sense that the two low-pass filters, commonly set to be identical, are now distinct and, as a result, one of them can have order less than the relative degree of the nominal plant. All of which are the direct consequence of a simplified configuration, we additionally present a design method for the two distinct low-pass filters to guarantee the internal stability of the system.},

keywords = {Stability},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{LeeJooShim12,

title = {Analysis of Discrete-time Disturbance Observer and a New Q-filter Design Using Delay Function},

author = {Chanhwa Lee and Youngjun Joo and Hyungbo Shim},

year  = {2012},

date = {2012-10-17},

booktitle = {Proc. of 2012 12th International Conference on Control, Automation and Systems (ICCAS)},

pages = {556-561},

publisher = {IEEE},

address = {JeJu Island, South Korea},

abstract = {In industrial applications, the disturbance observer (DOB) approach has been widely used due to its robustness and simple structure, and its results in a continuous-time fashion are frequently encountered in many literatures. Although most of DOBs are implemented in a discrete-time form with digital devices, a rigorous analysis on the discrete-time DOB is still insufficient compared to the continuous-time DOB. Therefore, in this paper, we mainly focus on the application of the DOB to discrete-time systems and some phenomena that are not observed in continuous-time systems. In particular, the time constant of the discrete-time Q-filter should have a lower bound, while the continuous-time DOB does not have this constraint. The time constant to sampling time ratio of the discrete-time Q-filter plays a crucial role in the discrete-time DOB, and it is suggested that this ratio be one for stability. Based on the above analysis, a new design method of the discrete-time Q-filter using a delay function is proposed. Furthermore, a robust stability condition for discrete-time systems using the delay function Q-filter is presented. Finally, simulation with an optical disk drive (ODD) model demonstrates the effectiveness of the newly proposed Q-filter.},

keywords = {Continuous-time system, Stability},

pubstate = {published},

tppubtype = {inproceedings}

}