• Title/Summary/Keyword: feedback gains

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The determination of state feedback gains of XPTOS for disk drive servomechanism based on BESSEL filter prototype (XPTOS에 의한 디스크 드라이브 서보메커니즘의 구성시 BESSEL 필터 표준 함수에 근거한 상태피드백이득 결정)

  • Han, K.H.;Lee, J.S.
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.980-983
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    • 1996
  • This paper presents the method of determining state feedback gains of XPTOS for disk drive servomechanism based BESSEL filter prototype. A typical disk drive actuator can be modeled as second order dynamics for low frequencies. However, the response at higher frequencies shows resonant behavior which cannot be easily modeled. XPTOS consists of the nonlinear control region and the linear control region. In the linear control region, the poles of a second order nominal model of plant must be properly relocated by pole placement technique to attenuate resonant modes at high frequency and to attain minimum time state transition. It is difficult to select position to satisfy this object because velocity feedback gain is subjected to position feedback gain in XPTOS. Here poles of BESSEL filter prototype are selected to determine state feedback gains of XPTOS. Simulation results for disk drive servomechanism using XPTOS having state feedback gains by the proposed method are presented.

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Model updating using the feedback exciter : The decision of sensor location & feedback gain (궤환 제어를 이용한 모델 개선법 : 측정 센서 위치와 궤환 이득값 설정)

  • 정훈상;박영진
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.802-807
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    • 2002
  • The updating of FE model to match it with the experimental results needs the modal information. There are two cases where this methodology is ill-equip to deal with; under-determined and ill-conditioning problem. The feedback exciter that uses the summation of the white noise and the signals from the measurement sensors multiplied with feedback gains can deal with these problems as the new modal data from the closed loop system generate more constraints the updating parameters should obey. The new modal data from the closed loop system should be different to enhance the condition of the modal sensitivity matrix. In this research, a guide for the selection of the sensor locations and the decision of the corresponding output feedback gains is proposed. This method is based on the sensitivity of the modal data with respect to the feedback gains. Through the proper selection of the exciter and sensor locations and the feedback gain, the eigenvalue sensitivity of the updating parameters which cause the ill-conditioning of the modal sensitivity matrix can be modified and consequently the error contamination in updating parameters are reduced.

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Optimal Output P and PI Feedback for Discrete Time Systems (리산시스템을 위한 최적출력 P&PI궤환)

  • 신현철;변증남
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.17 no.6
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    • pp.38-43
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    • 1980
  • For linear discrete-time time-invariant multi-input mufti-output systems, a necessary condition which an optimal output Proportional feedback gains must satisfr is deiived. Quadratic performance index is used. The result is extended to the desi01 problem for determining optimal output proportional plus integral feedback gains. For illustration, an example problem is solved and discussed.

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Performance sensitivity analysis of feedback system for adaptive control of a vehicle suspension (자동차 현가장치의 적응제어를 위한 feedback 시스템의 성능감도 해석)

  • Park, H;Jeon, E. S.;Oh, J. E.
    • Journal of the korean Society of Automotive Engineers
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    • v.13 no.1
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    • pp.35-45
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    • 1991
  • A linear quarter model of a vehicle suspension system is built and simulated. Especially the so-called sensitivity analysis is conducted in order to show its applicability to design problems, and sensitivity function is determined in the frequency domain. The change of frequency response function is predicted, which depends on the design parameter variation and the property is verified by computer simulation. Typical performance measures, namely, sprung mass acceleration, suspension deflection, and tire deflection are examined. The vehicle model is analyzed for ist performance sensitivity as a function of the system's feedback gains. The variable feedback gains are selected as the spring and damping coefficients. Frequency response, RMS response, and performance index of the performance evaluation variables are considered and three-dimensional and contour plots of response surfaces are formed to examine output sensitivity to suspension feedback. Performance trade-offs over the entire frequency spectrum are identified from the FRF, and that between ride quality and handling characteristics are examined from the RMS responses.

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Design of a Auto-Tuning Digital PID Controller using Relay feedback and Time Delay (시간 지연 릴레이 피드백을 이용한 자동동조 디지털 PID 제어기의 설계)

  • 류경모;박정일
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.109-109
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    • 2000
  • In process industries, more than 90% of the control loops have PID controller. Futhermore, the most control systems are using classical PID controllers for their process control. Various auto-tuning methods of PID gains using relay-feedback are presented recently. In order to get the desired control performance, the correct tuning of PID controller is very important. This paper suggests how to tune of digital PID gains using information for both the Nyquist critical point by conventional method and another point by the relay feedback and hidden time-delay term. Simulation results show that the proposed controller has better performance than the conventional method.

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Development of an Adaptive Feedback based Actuator Fault Detection and Tolerant Control Algorithms for Longitudinal Autonomous Driving (적응형 되먹임 기반 종방향 자율주행 구동기 고장 탐지 및 허용 제어 알고리즘 개발)

  • Oh, Kwangseok;Lee, Jongmin;Song, Taejun;Oh, Sechan;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.12 no.4
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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.

A study on design and control of hydraulic test rig for performance evaluation of active suspension system (능동 현가시스템의 성능평가를 위한 유압식 시험기의 설계 및 제어에 관한 연구)

  • 손영준;이광희;이진걸
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.1445-1449
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    • 1996
  • To evaluate of active suspension, it is necessary for special equipment - so called Test Rig which can perfectly realize the road condition and the impact from the road. And most of the test rig systems controlling force accurately and rapidly consist of electro-hydraulic servo mechanism, and they need robust controller which can endure outer road change. But in the case of PID controller, we should choose its best gains by trial and error method, and once its gains are fixed, they cannot get changed, so we should reset PID controller gains respectively when the road is changed. Therefore based on the load pressure feedback compensation method, our aim at constructing electro-hydraulic test rig is not affected by various road disturbance.

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A New Auto-Tuning PI Controller by Pattern Recognition (패턴 인식에 의한 새로운 자동조정 PI제어기)

  • Park, Gwi-Tae;Lee, Kee-Sang;Park, Tae-Hong
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.40 no.7
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    • pp.696-705
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    • 1991
  • This paper describes the procedures for pre-tuning and re-tuning the gains of PI controller based on output patterns -output error integral- of the unknown process which may not have any information, for example, system order, deadtime, time constant, etc. The key ideas of the proposed adaptive scheme are as follows. The scheme determines the initial gains by using ZNM (Ziegler-Nichols Method) with relay feedback, and then the adaptive algorithms by pattern recognition are introduced for re-runing the PI gains with on-line scheme whenever control conditions are changed. Because, among the various auto-tuning procedures, ANM with relay feedback has the difficulty in re-tuning with on-line and Bristol method has no comment on initial settings and has variables to pre-determine, which makes the algorithm comples, the proposed methods have the combined scheme with above two procedures to recover those problems. And this paper proposes a simple way to determine adaptive constant in Bristol method. To show the validity of the proposed method, an example is illustrated by computer simulation and a laboratory process, heat exchanger, is experimented.

Control of Crane Systems by a Digital Redesign Method (디지탈재설계법에 의한 크레인계의 제어)

  • 이동철;신민생;하주식;김상봉
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.1
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    • pp.41-52
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    • 1992
  • An algorithm of transforming continuous-time state feedback gains into equivalent discrete-time feedback gains or vice versa is proposed using bilinear transformation. The proposed method is evaluated experimentally by an application control of a mobile crane system which is implemented by 16bits micro computer with A/D and D/A converters. It has been shown from the experimental result that the transformed feedback gains are virtually identical to the optimal discrete gain over range of significant sampling time. Since the transformed matrix is composed by a distinct relationship between continuous-time gain and discrete-time gain, it is noted that the proposed method can be regarded as an explicit gain transformation method compared to the other methods using series expansion.

Static output feedback pole assignment of 2-input, 2-output, 4th order systems in Grassmann space

  • Kim, Su-Woon;Song, Seong-Ho;Kang, Min-Jae;Kim, Ho-Chan
    • Journal of IKEEE
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    • v.23 no.4
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    • pp.1353-1359
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    • 2019
  • It is presented in this paper that the static output feedback (SOF) pole-assignment problem of some linear time-invariant systems can be completely resolved by parametrization in real Grassmann space. For the real Grassmannian parametrization, the so-called Plucker matrix is utilized as a linear matrix formula formulated from the SOF variable's coefficients of a characteristic polynomial constrained in Grassmann space. It is found that the exact SOF pole assignability is determined by the linear independency of columns of Plucker sub-matrix and by full-rank of that sub-matrix. It is also presented that previous diverse pole-assignment methods and various computation algorithms of the real SOF gains for 2-input, 2-output, 4th order systems are unified in a deterministic way within this real Grassmannian parametrization method.