• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.491-492
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• 2016

This paper presents a robust feedback control design to mitigate the effect of grid voltage disturbances for three-phase grid-connected inverters in distributed generation systems. The proposed strategy consists of two major design steps. First, the controller is synthesized using the internal model principle to achieve a good reference tracking and disturbance rejection performance. Then, the feedback gain is systematically obtained by solving the linear matrix inequality conditions which are directly derived from the stability criteria. The main contribution of this paper is that the complexity of control structure can be substantially reduced and transient response is improved as compared with the existing robust control design methods. The simulation results are given to prove the validity of the proposed control scheme.

• Journal of Advanced Marine Engineering and Technology
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• 제24권2호
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• pp.50-56
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• 2000

This paper presents the design of an optimal state feedback controller for container cranes under some design specifications. To do this, the nonlinear equation of a container crane system is linearized and then augmented to eliminate the steady-state error, and some constraints are derived from the design specifications. Designing the controller involves a constrained optimization problem which classical gradient-based methods have difficulties in handling. Therefore, a real-coding genetic algorithm incorporating the penalty strategy is used. The responses of the proposed control system are compared with those of the unconstrained optimal control system to illustrate the efficiency.

• International Journal of Aeronautical and Space Sciences
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• 제15권1호
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• pp.74-81
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• 2014

This article documents the design of a novel two-loop acceleration autopilot based on $\mathcal{L}_1$ adaptive output feedback control for tail-controlled missiles. The inner loop is an adaptive angle-of-attack tracking loop and the outer loop is the traditional PI controller for error compensation. A systematic low-pass filter design procedure is provided for minimum phase system and is applied to the inner loop design while the parameters of the outer loop are obtained from the multi-objective optimization problem. The effectiveness of the proposed autopilot is verified through numerical simulations under various conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.510-512
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• 1999

In this paper, we present a method for the analysis and design of fuzzy controller for nonlinear systems. In the design procedure, we represent the dynamics of nonlinear systems using a Takagi-Sugeno fuzzy model and formulate the controller rules, which shares the same fuzzy sets with the fuzzy system, using parallel distributed compensation method. Then, after the feedback gain of each local state feedback controller is obtained using the existing optimal pole-placement scheme, we construct an overall fuzzy logic controller by blending all local state feedback controller. Finally, the effectiveness and feasibility of the proposed fuzzy-model-based controller design method has been evaluated through an inverted pendulum system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1943-1945
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• 2001

In this paper, we present an adaptive output feedback control scheme for a class of uncertain nonlinear output-feedback form with time-varying parameters to which adaptive observer backstepping technique may not be applicable directly. In observer design, with the introduction of design function, we can deal with time-varying parameters in a very effective way. By the presented scheme, estimation error can be tuned to a desired small region around the origin via the design constants. Consequently, the observer with the presented design functions and the backstepping methodology achieve a robust regulation of the output tracking error while maintaining boundedness of all the signals and states.

• 공학교육연구
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• 제21권6호
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• pp.44-53
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• 2018

The purpose of this paper is to develop a technical writing model suitable for engineering students based on the practice of technical writing using the patent application form for engineering students. The Dick & Carey model was used to design the teaching of technical writing using the patent application form. In particular, the instructor communicates with the learner and instructs the learner to produce and express students' own ideas. Instruction design in technical writing progresses consists of four steps, such as creating ideas by brainstorming, comprising contents, exercising writing, and feedback. Feedback occurs between an instructor and a learner and also does among students. As writing is proceeding step by step, instruction design for technical writing should come forth with specific methods to make students practice writing in work. Following these steps will help engineering school students to make up new products after graduating university.

• 자동차안전학회지
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• 제12권4호
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• pp.13-22
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• 2020

This paper presents an adaptive feedback based actuator fault detection and tolerant control algorithms for longitudinal functional safety of autonomous driving. In order to ensure the functional safety of autonomous vehicles, fault detection and tolerant control algorithms are needed for sensors and actuators used for autonomous driving. In this study, adaptive feedback control algorithm to compute the longitudinal acceleration for autonomous driving has been developed based on relationship function using states. The relationship function has been designed using feedback gains and error states for adaptation rule design. The coefficients in the relationship function have been estimated using recursive least square with multiple forgetting factors. The MIT rule has been adopted to design the adaptation rule for feedback gains online. The stability analysis has been conducted based on Lyapunov direct method. The longitudinal acceleration computed by adaptive control algorithm has been compared to the actual acceleration for fault detection of actuators used for longitudinal autonomous driving.

• Journal of Communications and Networks
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• 제15권6호
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• pp.589-600
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• 2013

In this paper, we propose a new feedback scheme called mode selection-based feedback by scheduling probability prediction (SPP-MF) for channel state feedback in OFDMA downlink system. We design the scheme such that it determines the more desirable feedback mode among selective feedback by scheduling probability prediction (SPP-SF) mode and bitmap feedback by scheduling probability prediction (SPP-BF) mode, by calculating and comparing the throughputs of the two modes. In both feedback modes, each user first calculates the scheduling probability of each subchannel (i.e., the probability that a user wins the scheduling competition for a subchannel) and then forms a feedback message based on the scheduling probability. Specifically, in the SPP-SF mode, each user reports the modulation and coding scheme (MCS) levels and indices of its best S subchannels in terms of the scheduling probability. In the SPP-BF mode, each user determines its scheduling probability threshold. Then, it forms a bitmap for the subchannels according to the scheduling probability threshold and sends the bitmap along with the threshold. Numerical results reveal that the proposed SPP-MF scheme achieves significant performance gain over the existing feedback schemes.

• 한국컴퓨터그래픽스학회논문지
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• 제26권3호
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• pp.79-86
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• 2020

코어운동의 운동 효과를 높이기 위해서는 정확한 자세로 운동 하는 것이 중요하다. 본 논문은 가상현실 환경에서 코어 운동을 하는 사용자가 정확한 자세를 취할 수 있도록 피드백을 제공하여 운동 자세를 트레이닝 할 수 있는 시스템을 소개한다. 스쿼트, 런지, 브릿지의 총 3가지 코어 운동 자세를 대상으로 하였으며, 정확한 자세를 취할 수 있도록 시각 피드백과 촉각 피드백을 사용자에게 제공한다. 전문가의 자세를 사용자의 신체 길이에 맞게 조정하여 기준 자세를 생성하며, 사용자의 운동 자세를 기준 자세와 비교하여 운동 자세의 정확도를 계산한다. 사용자 실험을 통해 피드백의 효과를 입증하였으며, 피드백의 설계에 따른 트레이닝 효과를 비교하였다.

• Physical Therapy Rehabilitation Science
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• 제10권2호
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• pp.147-155
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• 2021

Objective: This study is to investigate the effect of real-time feedback from the therapist on posture, muscle strength, pain of subjects with forward head posture based on a non-face-to-face complex exercise program. Design: Two-group pretest-posttest design. Methods: Thirty healthy men and women in their twenties with forward head posture with a Craniovertebral angle of 52° or less were targeted, the final selection was made as 15 experimental groups who performed the non-face-to-face intervention program while receiving real-time feedback and 15 control subjects who performed the non-face-to-face intervention program without providing feedback. Six of them were eliminated, and a total of 24 were conducted as subjects. All exercise groups performed an exercise program three times a week, 30 minutes each, for a total of two weeks. Before and after exercise, Craniovertebral angle (CVA), CranioRotation angle (CRA), muscle strength, and tenderness threshold were evaluated. Results: Significant differences were shown in both groups in CVA, and tenderness threshold before and after exercise (p<0.05), and CRA, the left middle trapezius muscle strength, only in the experimental group (p<0.05). In the comparison of theamount of change between exercise groups, the group that received feedback on CVA, CRA and tenderness threshold showed a significant change than the group without feedback (p<0.05). Conclusions: As a result of this study, it can be seen that the therapist's real-time feedback is more effective in improving the forward head posture. This requires feedback from the therapist on posture correction during non-face-to-face exercise intervention.