• Title, Summary, Keyword: simplified adaptive control

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Slewing maneuver control of flexible space structure using adaptive CGT

  • Shimada, Yuzo
    • 제어로봇시스템학회:학술대회논문집
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    • pp.47-50
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    • 1995
  • This paper concerns an adaptive control scheme which is an extension of the simplified adaptive control. Originally, the SAC approach was developed based on the command generator tracker (CGT) theory for perfect model tracking. An attractive point of the SAC is that a control input can be synthesized without any prior knowledge about plant structure. However, a feedforward dynamic compensator of the CGT is removed from the basic structure of the SAC. This deletion of the compensator makes perfect model tracking difficult against even a step input. In this paper, an adaptive control system is redesigned to achieve perfect model tracking for as long as possible by reviving the dynamic compensator of the CGT. The proposed method is applied to slewing control of a flexible space structure and compared to the SAC responses.

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Nonlinear Adaptive Control based on Lyapunov Analysis: Overview and Survey (리아프노브 분석법 기반 비선형 적응제어 개요 및 연구동향 조사)

  • Park, Jin Bae;Lee, Jae Young
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.3
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    • pp.261-269
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    • 2014
  • This paper provides an overview of the basics and recent studies of Lyapunov-based nonlinear adaptive control, the aim of which is to improve or maintain the performance and stability of the closed-loop system by cancelling out the presumable uncertainties in the nonlinear system dynamics. The design principles are essentially based on Lyapunov's direct method. In this survey, we provide a comprehensive overview of Lyapunov-based nonlinear adaptive control techniques with simplified effective design examples, which are to be elaborated as related recent results are gradually shown. The scope of the survey contains research on singularity problems in adaptive control, the techniques to deal with linearly and nonlinearly parameterized uncertainties, robust neuro-adaptive control, and adaptive control methodologies combined with various nonlinear control techniques such as sliding-mode control, back-stepping, dynamic surface control, and optimal/$H_{\infty}$ control.

An Adaptive Fuzzy Sliding Mode Controller for Robot Manipulators

  • Seo, Sam-Jun;Park, Gwi-Tae;Kim, Dongsik
    • 제어로봇시스템학회:학술대회논문집
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    • pp.162.1-162
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    • 2001
  • In this paper, the adaptive fuzzy system is used as an adaptive approximator for robot nonlinear dynamic. A theoretical justification for the adaptive approximator is proving that if the representive point(RP or switching function) and its derivative in sliding mode control are used as the inputs of the adaptive fuzzy system, the adaptive fuzzy system can approximate robot nonlinear dynamics in the neighborhood of the switching surface. Thus the fuzzy controller design is greatly simplified and at the same time, the fuzzy control rule can be obtained easily by the reaching condition. Based on this, a new method for designing an adaptive fuzzy control system based on sliding mode is proposed for the trajectory tracking control of a robot with unknown nonlinear dynamics.

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Control of $NH_4-N$ in Wastewater Treatment Effluent According to Simplified ASM No. 1 (간략화된 활성슬러지 모델(ASM No. 1)을 이용한 유출수 중 암모니아성 질소의 제어에 관한 연구)

  • Kim, Shin-Geol;Choi, In-Su;Koo, Ja-Yong
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.5
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    • pp.548-555
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    • 2007
  • The control of wastewater treatment has two merits; one is to regulate water quality of effluent and the other is to reduce the cost of wastewater treatment. The purpose of this study was to control the ammonium nitrogen in effluent that is known to cause eutrophication. The control was based on simplified ASM No. 1 which had 3 component materials and 8 coefficients, and the control method was as following. Firstly the ammonium concentration of inflow was measured and the optimal aeration time in effluent was determined according to simplified ASM No. 1 to be 1.0 mg/L. If ammonium concentration of effluent was not equal to 1.0 mg/L, the influent ammonium was corrected by adaptive control. These processes above were repeatedly performed. The SBR running aerobic-anoxic phase had been controlled for 1 month with this method. As a result, the ammonium concentration of the effluent showed in the range of $0.22\sim3.1$ mg/L with an average concentration of 1.1 mg/L. The adaptive control method used in this study was found very useful to control and predict the effluent concentration of ammonium.

Robust Adaptive Control of A HexaSlide Type Parallel Manipulator

  • Kim, Jong-Phil;Kim, Sung-Gaun;Ryu, Jeha
    • Transactions on Control, Automation and Systems Engineering
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    • v.3 no.4
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    • pp.262-267
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    • 2001
  • Jeha Ryu Department of Mechatronics, Kwangju Institute of Science and Technology This paper presents an application of a robust adaptive control strategy to HexaSlide type six degrees-of-freedom parallel manipulators. The HexaSlide type parallel manipulators are characterized as an architecture with constant link lengths that are attached to moving sliders on the ground and to a mobile platform. The proposed control law is developed based on a simplified second order system dynamic equation in joint space with uncertain mass, damper, spring, and Coulomb friction terms. These uncertain parameters are updated by an adaptation law that is derived by Lyapunov stability theorem. A robust adaptive control law by using the boundary layer is designed for the purpose of compensating for the neglected dynamic effects of the mobile platform and the six moving links that are modeled as a disturbance term. Experimental results show good and fast tracking performance.

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Adaptive Hysteresis Band Current Control Independent of the Back EMFs (역기전력에 무관한 가변 히스테리시스 밴드 전류 제어)

  • Kim, Kyeong-Hwa;Cho, Kwan-Yuhl;Chung, Se-Kyo;Oh, Dong-Seong;Youn, Myung-Joong
    • Proceedings of the KIEE Conference
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    • pp.1172-1175
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    • 1992
  • The conventional adaptive hysteresis band current control technique has disadvantages such that on-line calculation of the hysteresis band is very complex, therefore, the adaptive hysteresis band must be stored in the look-up table. In this paper, a new simplified adaptive hysteresis band current control technique with phase decoupling is presented. The adaptive band is independent of the back EMFs. Using this adaptive band and the phase decoupled current error, the modulation frequency is fixed at nearly constant and the PWM inverter has optimal switching pattern.

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Control of Wastewater Treatment Removing Phosphate Based on ASM No. 2 Simplified Model and Investigation of Luxury Uptake Limitation (ASM No. 2 간략화 모델에 기초한 인산염의 제어 및 인섭취 제한현상에 대한 고찰)

  • Kim, Shin-Geol;Choi, In-Su;Koo, Ja-Yong
    • Journal of Korean Society of Environmental Engineers
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    • v.30 no.2
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    • pp.181-189
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    • 2008
  • Phosphate is the limiting factor leading to the eutrophication in nature and has been usually removed by the luxury uptake of PAOs(Phosphate accumulating organisms). The purpose of this study was the control of wastewater treatment removing phosphorus. The control of wastewater treatment process was performed by optimal and adaptive control. They were performed as followings. Firstly the inflow phosphate concentration was measured and the optimal aeration time was calculated by simplified ASM No. 2 for the phosphate to be 1.0 mg/L in effluent. It was optimal control. But when the phosphate concentration in effluent was not 1.0 mg/L, adaptive control was necessary to coincide the objective of control with real value. Then it was performed as the objective phosphate concentration in effluent was changed according to calculation of errors and it was adaptive control. The wastewater treatment process had been controlled by them for about one month. The range of phosphate concentration in effluent 0.2$\sim$3.2 mg/L and the average of it was 1.0 mg/L. The limitation of luxury uptake occurred two times while wastewater treatment process was running. After the analysis of laboratory tests, we knew the reasons were the shortage of ammonia nitrogen and the excessive aeration.

A Study on The Jump Error Smoothing Scheme by Fuzzy Logic

  • Lee, Tae-Gyoo;Kim, Kwang-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • pp.56.3-56
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    • 2001
  • This study describes the jump error smoothing scheme with fuzzy logic based on the scalar adaptive filter. The scalar adaptive filter is an useful algorithm for smoothing abrupt jump errors. However, the performances of scalar adaptive algorithm depend on the variance of real signal. So to design an effective algorithm, many informations of real and jump signal are required. In this paper, the fuzzy rules are designed by the analysis of scalar adaptive filter, and then the improved and simplified scheme is developed for smoothing the jump error. Simulations to INS/GPS integrated system show that the proposed method is effective.

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ADAPTIVE CHANDRASEKHAR FILLTER FOR LINEAR DISCRETE-TIME STATIONALY STOCHASTIC SYSTEMS

  • Sugisaka, Masanori
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1041-1044
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    • 1988
  • This paper considers the design problem of adaptive filters based an the state-space models for linear discrete-time stationary stochastic signal processes. The adaptive state estimator consists of both the predictor and the sequential prediction error estimator. The discrete Chandrasakhar filter developed by author is employed as the predictor and the nonlinear least-squares estimator is used as the sequential prediction error estimator. Two models are presented for calculating the parameter sensitivity functions in the adaptive filter. One is the exact model called the linear innovations model and the other is the simplified model obtained by neglecting the sensitivities of the Chandrasekhar X and Y functions with respect to the unknown parameters in the exact model.

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Adaptive control for two-link flexible robot arm (2-링크 유연한 로보트 팔에 대한 적응제어)

  • 한종길;유병국;임규만;함운철
    • 제어로봇시스템학회:학술대회논문집
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    • pp.8-13
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    • 1993
  • This paper presents deterministic and adaptive control laws for two-link flexible arm. The flexible arm has considerable structural flexibility. Because of its flexbility, dynamic equations are very complex and difficult to get, dynamic equations for two-link flexible arm are derived from Bernoulli-Euler beam theory and Lagrangian equation. Using the fact that matrix is skew symmetric, controllers which have a simplified structure with less computational burden are proposed by using Lyapunov stability theory.

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