• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.644-647
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• 1997

Asymmetric cylinders are usually used as an actuator of active suspensions. The conventional optimal controller design does not include actuator dynamics as a state and force controller is needed to track the desired force. But the actuator is not ideal, so performance of an active suspension system is degraded. In this paper, we take account nonlinear actuator dynamics and obtain a linear model using a feedback linearization technique then apply optimal control method. Effectiveness of proposed method is demonstrated by numerical simulation of 1/4 car model.

• 제어로봇시스템학회논문지
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• 제7권7호
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• pp.614-621
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• 2001

The controllers for a full car 7-DOF model with 4 active or semi-active suspension units are designed and evaluated in this research. The control algorithms for suspension systems, such as full state feedback active, full state feedback semi-active, sky-hook active, sky-hook semi-actvie, and on-off suspension systems, are analyzed and evaluated with respect to ride comfort. The vehicle dynamic performances are expressed by response curves to a bump input, performance indices for asphalt road input, and frequency characteristic curves. Heaving, rolling, and pitching inputs are applied to the vehicle dynamic system to evaluate frequency characteristics. The simulation results show that the ride quality of the sky-hook controller approaches that the full state feedback controller more closely in semi-active suspension system than in active suspension system. For the implementation of a vehicle with sky-hook suspension control systems in this paper, 7 velocity sensors are required to measure the states.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.457-462
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• 2006

This paper is concerned with the active vibration control experiment on cylindrical shell equipped with Macro Fiber Composite(MFC) actuators. The MFC actuators were glued to the cylindrical shell in circumferential directions. To verify the theoretical result, vibration test using impact hammer and accelerometer was carried out. It was found from experiments that theoretical result predicts experimental result to some extent. The positive position feedback controllers were designed and applied to the test article. It was observed that the resonant amplitude of the fundamental mode was reduced by 20dB thus achieving active vibration control. The active vibration control of the response subject to non resonant excitation has been of interest. We developed the combination of the positive position feedback controller which can cope with the fundamental mode and the positive position feedback controller which can counteract the external disturbance with non resonant frequency. It was found from experiments that the hybrid controller can suppress the vibration amplitude successfully.

• Journal of Power Electronics
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• 제16권4호
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• pp.1565-1577
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• 2016

For grid-connected LCL-filtered inverters, dual-loop current control with an inner-loop active damping (AD) based on capacitor current feedback is generally used for the sake of current quality. However, existing studies on capacitor current feedback AD with a control delay do not reveal the mathematical relation among the dual-loop stability, capacitor current feedback factor, delay time and LCL parameters. The robustness was not investigated through mathematical derivations. Thus, this paper aims to provide a systematic study of dual-loop current control in a digitally-controlled inverter. At first, the stable region of the inner-loop AD is derived. Then, the dual-loop stability and robustness are analyzed by mathematical derivations when the inner-loop AD is stable and unstable. Robust design principles for the inner-loop AD feedback factor and the outer-loop current controller are derived. Most importantly, ensuring the stability of the inner-loop AD is critical for achieving high robustness against a large grid impedance. Then, several improved approaches are proposed and synthesized. The limitations and benefits of all of the approaches are identified to help engineers apply capacitor current feedback AD in practice.

• 소음진동
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• 제4권4호
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• pp.497-505
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• 1994

This paper presents a design scheme of the active noise absorber that consists of the feedforward and feedback controller. The feedback controller aims to increase damping for the specific acoustic mode. The feedforward controller synthesizes the input signal coherent with the primary noise source in order to attenuate the noise field in the broad frequency range. The feedforward controller is adapted to the variation of acoustic plants using the proposed algorithm which compensates the effect of feedback link. Experimental results demonstrate that the proposed method is effective for the active control of band-limited noise fields in the enclosure.

• 스마트미디어저널
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• 제6권4호
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• pp.79-87
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• 2017

본 논문은 기존 노년층과는 다른 특성을 보이는 액티브 시니어의 사용자 경험 문제를 도출해 내기 위한 연구로 먼저 선행 연구분석을 통하여 'Visible', 'Desired Outcome', 'Immediate Feedback', 'Intuitiveness', 'Perceived Ease of Use'의 다섯 가지 요소를 사용자 interaction의 초기단계를 이루는 요소로 추출하였고 이를 기반으로 Interface 사용 중에 사용자의 행위와 인지 내용을 분석하였다. 이를 통해 사용과정에서 생기는 문제점을 도출하였으며, 다섯 가지 요소와 사용자의 주관 평가 간의 상관관계를 분석하였다. 사용자 경험의 주관 평가에는 PSSUQ를 사용하였으며 SPSS 22 버전을 사용하여 pearson 상관 분석을 실시하였다. 본 논문의 연구결과는 다음과 같다. 첫째, App 사용 시 액티브 시니어 사용자들이 겪는 가장 큰 문제는 desired outcome차원의 문제로 볼 수 있다. 둘째, interface assessment 다섯 가지 요소 중 'Desired Outcome', 'Perceived Ease of Use' 두 가지 요소만이 PSSUQ 설문 결과와 통계적으로 유의미한 상관관계를 보이는 것으로 나타났으며 나머지 'Visible', 'Immediate Feedback', 'Intuitiveness'의 세 요소는 사용자의 주관 평가와 상관관계를 보이지 않았다. 본 논문의 연구결과에 의하면 액티브 시니어는 기존의 노년층과는 다른 특징을 가지고 있어 'Desired Outcome'과 'Perceived ease of use'차원의 문제가 더 많은 영향을 미치는 요소로 볼 수 있으며 기존의 연구에서 중요한 요소로 거론한 'Visible', 'Immediate feedback', 'Intuitiveness'는 명확한 상관관계가 없는 것으로 볼 수 있다. 이는 기존 노년층과 달리 액티브 시니어의 경우 PC나 스마트폰 사용 경험의 누적으로 인하여 visible, immediate feedback, intuitiveness 등의 요소에 어려움을 적게 겪기 때문인 것으로 보인다. 본 논문의 연구 결과는 다양한 수요를 보이고 있는 액티브 시니어용 App의 개발에 의미 있게 활용될 것이다.

• 한국의류학회지
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• 제41권6호
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• pp.1022-1038
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• 2017

Wearable smart products contributed to expand the concept of modern clothing in terms of closer communication between wearers and the surrounding environment. This study investigated the concept of wearable smart actuators and characteristics of actuating feedback. The representative product development trends over the past 10 years are examined based on the method of actuating feedback. A first keyword search from Naver and Google reused to select the final 58 products based on the second key keyword actuating feedback. The wearable smart actuator system works in a similar way to a human body system such as those of the information processing process. Actuating feedback is delivered directly to the user as the last signal of the system, which has visual, auditory and tactile feedback. It works in complex at the device to be delivered to the user. Actuator feedback is divided into three types of active and passive, depending on the user situation, the overall purpose of the product, the collected information, and the device dependency. Active actuating feedback determines and actuates the situation on behalf of the user when the user is in an emergency or a disability situation. Passive actuating feedback plays a role in environmental monitoring to help in a healthy daily life.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.238-239
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• 2008

In this paper, active noise control (ANC) of a Volterra system with a nonlinear secondary path is proposed in the presence of a linear acoustic feedback, whereby the conventional ANC of a linear system with online acoustic feedback-path modeling is further extended to ANC of a Volterra system with a linear acoustic feedback path. In particular, the proposed ANC system consists of two adaptive Volterra filters (for nonlinear noise control and nonlinear adaptive noise cancellation) and one feedback-path modeling filter. Simulation results show that the proposed approach yields more effective reduction of disturbances arising from the acoustic feedback, in addition to high nonlinear ANC performance.

• 전기학회논문지
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• 제59권5호
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• pp.1001-1004
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• 2010

Acoustic feedback and background noise variation can degrade the performance of an active noise control (ANC) system. In this paper, nonlinear ANC using a non-parametric VSS-NLMS (or NPVSS-NLMS) algorithm and online feedback path modeling is proposed, whereby the conventional linear ANC with online acoustic feedback-path modeling is further extended to nonlinear Volterra ANC with a linear acoustic feedback path. In particular, the step-size of the NPVSS-NLMS algorithm is controlled to reduce the effect of background noise variation in the ANC system. Simulation results demonstrate that the proposed approach yields better nonlinear ANC performance compared with the conventional nonlinear ANC method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.310-313
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• 2005

This paper is concerned with the active vibration control of beam equipped with piezoceramic sensors and actuators. The single-input and single-output positive position feedback controller is considered as an active vibration controller for the beam. The proposed single-input and single-output positive position feedback controller can cope with many modes of interest by summing each positive position feedback controller designed for each mode. In this paper, theoretical formulation is first explained in detail. We discuss how to design the single-input and single-output positive position feedback controller for a target structure by considering Euler-Bemoulli beam. It is found that the theories developed in this study are capable of predicting the control system characteristics and its performance.