• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.388-391
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• 2003

Disturbance observer(DOB) is effective to enhance the performance of system in the presence of disturbances. Various types of disturbance observer have been proposed to improve sensitivity function of system. However, it has been observed that current DOBs tend to bring poor transient response due to cross-couplings. This paper proposes a new type of disturbance observer to reduce effect of cross-couplings and provide simpler structure than Dual DOB. Finally, we verify the performance of the proposed DOB through numerical simulations.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.3
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• pp.89-94
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• 2000

A novel observer design methodology for linear time-invariant systems named the dynamic observer is presented. Efficient and plausible design algorithms are also provided. The dynamic observer is an extension of the usual static observer. The concept of the dynamic observer enlarges the capacity of observer design so much that well-developed advanced linear controller design techniques can be utilized to design observers. Both the dynamic observers in the form of standard and Luenburger types are considered. The essential characteristics of the dynamic observer to be qualified as an effective observer design scheme are addressed.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.356-364
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• 2017

This paper presents a force control based on the observer without taking any force or torque measurement from the robot which allows realizing more stable and robust human robot interaction for the developed multi-functional upper limb rehabilitation robot. The robot has four functional training modes which can be classified by the human robot interaction types: passive, active, assistive, and resistive mode. The proposed observer consists of internal disturbance observer and external force observer for distinctive performance evaluation. Since four training modes can be quantitatively identified as impedance variation, position-based impedance control with feedback and feedforward controller was applied to the assistive training mode. The results showed that the proposed sensorless observer estimated cleaner and more accurate force compared to the force sensor and the impedance controller embedded with the proposed observer completed the assistive training mode safely and properly.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.6
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• pp.487-493
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• 2001

In this paper, a new reduced-order dynamic observer method is presented. Two types of observers are pronounced, namely, the model based reduced-order dynamic observer and the Luenburger type reduced-order dynamic observer. Useful design algorithms are also provided for each structure. The essential features of the proposed observed design methods are addressed to be qualified ad effective observers. The proposed method clarifies the duality between the controller and observer designs.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.6
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• pp.484-491
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• 2005

Using a disturbance observer is effective in enhancing the performance of dynamic system in presence of disturbances. Although various types of disturbance observers have been proposed to improve sensitivity of systems, there exist poor transient responses due to cross-couplings among disturbance observer loops. In this paper, dual disturbance observer (DOB) is proposed to reduce the effects of the cross-couplings. A different type of loop transfer function is proposed for external disturbance observer. While improving the sensitivity function by adding external DOB, it also provides improved complementary sensitivity function. The proposed dual DOB is applied to a commercial optical disk drive tracking system. It is shown that the dual DOB is an effective method in rejecting the effect of disturbance as well as improving the tracking performance.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.6
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• pp.311-317
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• 2023

This paper presents a sliding mode observer (SMO) for reconstructing cyber attacks affecting a system. The system is first re-expressed such that its design freedom is easier to manipulate. The SMO is then used to reconstruct the cyber attack affecting the system. A simulation example is used to verify the performance of the SMO under two types of cyber attacks, and its results demonstrate the effectiveness of our proposed scheme.

• Korean Journal of Culture and Social Issue
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• v.20 no.2
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• pp.107-131
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• 2014

This driving simulation study examined relative differences in driving anger as the functions of drivers' gender and driving experiences, and actor-observer perspectives when they were exposed in two anger-provoking driving scenarios(cutting-in and sudden stop). The results showed the followings. First, neither drivers' gender nor driving experience, when they were considered independently of the driving situation types and actor-observer perspectives, yielded significant difference in driving anger. Second, actor-observer effect on driving anger was observed only in the cutting-in condition where other driver's intension was emphasized. Third, the female drivers of low driving experience tended to show the strongest tendency of actor-observer bias in the cutting-in condition. These results suggested that the levels of driving anger as the functions of drivers' gender and driving experience can be differed by types of driving situation as well as perspectives of drivers' interpreting the situations.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.372-375
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• 2003

Using disturbance observer is effective to enhance tracking performance of system in the presence of disturbances. Various types of disturbance observers have been proposed to improve sensitivity of systems, but they tend to bring poor transient response due to cross coupling of inter-loops. In this paper, we propose dual disturbance observer(Dual DOB) which is designed to reduce the cross coupling. Dual DOB is consist of an internal DOB and an external DOB, that are designed for different object. The Dual DOB is applied to Optical Disk Drive tracking system. It is shown that the Dual DOB has improved performance over conventional DOB via experimental result. There is good agreement between simulation and experimental results.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.975-978
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• 2009

Even if auto-stereoscopic and polarization based 3D displays are not working with the same principles, their common aim is to provide two different images in the eyes of the observer. In this paper we show that Fourier optics instrument for viewing angle measurements can be applied to both types of displays. Luminance measurements are made at different locations and what will be seen by an observer in front of the display is predicted. Precise 3D characteristics can be derived and direct comparison becomes possible.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.5
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• pp.5-14
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• 2003

Tracking control schemes on the precise mechanical system in presence of nonlinear dynamic friction is proposed. A nonlinear dynamic friction is regarded as the bristle friction model to compensate fer effects of friction. The conventional SMC method often shows poor tracking performance in high-precision position tracking application since it cannot completely compensate for the friction effect below a certain precision level. Thus to improve the precise position tracking performance, we propose the SMC method combined with the disturbance observer having tunable transient performance. Then this control scheme has the high precise tracking peformance as well as a good transient response when it is compared with the conventional SMC method and the similar types of observers, The experiment on the XY ball-screw drive system with the nonlinear dynamic friction confirms the feasibility of the proposed control scheme.