Closed-Loop Input Shaping for Flexible Structures Using Time-Delay Control1

1999 ◽  
Vol 122 (3) ◽  
pp. 454-460 ◽  
Author(s):  
Vikram Kapila ◽  
Anthony Tzes ◽  
Qiguo Yan
Keyword(s):  
Time Delay ◽  
Closed Loop ◽  
Flexible Structures ◽  
System Stability ◽  
Structural Vibration ◽  
Delay Systems ◽  
Linear Matrix ◽  
Input Shaping ◽  
Closed Loop Control ◽  
Loop Control

Input shaping techniques reduce the residual vibration in flexible structures by convolving the command input with a sequence of impulses. The exact cancellation of the residual structural vibration via input shaping is dependent on the amplitudes and instances of impulse application. A majority of the current input shaping schemes are inherently open-loop where impulse application at inaccurate instances can lead to system performance degradation. In this paper, we develop a closed-loop control design framework for input shaped systems. This framework is based on the realization that the dynamics of input shaped systems give rise to time delays in the input. Thus, we exploit the feedback control theory of time delay systems for the closed-loop control of input shaped flexible structures. A Riccati equation-based and a linear matrix inequality-based frameworks are developed for the stabilization of systems with uncertain, multiple input delays. Next, the aforementioned framework is applied to two input shaped flexible structure systems. This framework guarantees closed-loop system stability and performance when the impulse train is applied at inaccurate instances. Two illustrative numerical examples demonstrate the efficacy of the proposed closed-loop input shaping controller. [S0022-0434(00)00103-9]

scholarly journals Robust LFC Strategy for Wind Integrated Time-Delay Power System Using EID Compensation

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3223 ◽  
Author(s):  
Liu ◽  
Zhang ◽  
Zou
Keyword(s):  
Time Delay ◽  
Power System ◽  
Closed Loop ◽  
Frequency Control ◽  
Loop System ◽  
Load Frequency Control ◽  
System Stability ◽  
Linear Matrix ◽  
Closed Loop System ◽  
The Stability

This paper presents an active disturbance rejection control (ADRC) technique for load frequency control of a wind integrated power system when communication delays are considered. To improve the stability of frequency control, equivalent input disturbances (EID) compensation is used to eliminate the influence of the load variation. In wind integrated power systems, two area controllers are designed to guarantee the stability of the overall closed-loop system. First, a simplified frequency response model of the wind integrated time-delay power system was established. Then the state-space model of the closed-loop system was built by employing state observers. The system stability conditions and controller parameters can be solved by some linear matrix inequalities (LMIs) forms. Finally, the case studies were tested using MATLAB/SIMULINK software and the simulation results show its robustness and effectiveness to maintain power-system stability.

scholarly journals Mixed H2/H∞ Control for Itô-type Stochastic Time-Delay Systems with Applications to Clothing Hanging Device

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yan Qi ◽  
Min Zhang ◽  
Zhiguo Yan
Keyword(s):  
Time Delay ◽  
Performance Index ◽  
Closed Loop ◽  
Delay Systems ◽  
Linear Matrix ◽  
Matrix Inequality ◽  
Time Delay Systems ◽  
Closed Loop Systems ◽  
Mean Square Stability ◽  
Stochastic Time

This paper deals with the problem of mixed H2/H∞ control for Itô-type stochastic time-delay systems. First, the H2/H∞ control problem for stochastic time-delay systems is presented, which considers the mean square stability, H2 control performance index, and the ability of disturbance attenuation of the closed-loop systems. Second, by choosing an appropriate Lyapunov–Krasoviskii functional and using matrix inequality technique, some sufficient conditions for the existence of state feedback H2/H∞ controller for stochastic time-delay systems are obtained in the form of linear matrix inequalities. Third, two convex optimization problems with linear matrix inequality constraints are formulated to design the optimal mixed H2/H∞ controller which minimizes the guaranteed cost of the closed-loop systems with known and unknown initial functions, and the corresponding algorithm is given to optimize H2/H∞ performance index. Finally, a numerical example is employed to show the effectiveness and feasibility of the proposed method.

Shaped Time-Optimal Feedback Controllers for Flexible Structures

2004 ◽  
Vol 126 (1) ◽  
pp. 173-186 ◽  
Author(s):  
Lucy Y. Pao ◽  
Chanat La-orpacharapan
Keyword(s):  
Phase Plane ◽  
Closed Loop ◽  
Flexible Structures ◽  
Input Shaping ◽  
Feedback Controllers ◽  
Control Laws ◽  
Loop Control ◽  
Flexible Mode ◽  
Time Optimal ◽  
Acceleration And Deceleration

This paper describes the design of closed-loop control laws for servomechanisms with one dominant flexible mode. An input shaping technique is employed to alter the rigid body phase-plane trajectory that is used in time-optimal servomechanisms. The resulting controllers lead to near time-optimal performance without unwanted residual vibrations. After the basic technique is outlined for a system with one undamped flexible mode, extensions are given considering different acceleration and deceleration capabilities, damping, and slew rate limits.

A sensitivity analysis of closed loop control systems on flexible structures

1991 ◽  
Author(s):  
STEVEN WEBB ◽  
JAMES SMITH ◽  
JEFFREY TURCOTTE ◽  
EPHRAHIM GARCIA
Keyword(s):  
Sensitivity Analysis ◽  
Control Systems ◽  
Closed Loop ◽  
Flexible Structures ◽  
Closed Loop Control ◽  
Loop Control

Increasing Robustness of Input Shaping Method to Parametric Uncertainties and Time-Delays

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
M. C. Pai ◽  
A. Sinha
Keyword(s):  
Time Delays ◽  
Closed Loop ◽  
Sliding Mode ◽  
Flexible Structures ◽  
System Stability ◽  
Flexible Structure ◽  
Input Shaping ◽  
Parametric Uncertainties ◽  
Residual Vibration ◽  
External Disturbances

The input shaping technique has proven to be highly effective in reducing or eliminating residual vibration of flexible structures. The exact elimination of the residual vibration via input shaping depends on the amplitudes and instants of utilized impulses. However, systems always have parametric uncertainties, which can lead to performance degradation. Furthermore, input shaping method does not deal with vibration excited by external disturbances and time-delays. In this paper, a closed-loop input shaping control scheme is developed for uncertain flexible structure and uncertain time-delay flexible structure systems. The algorithm is based on the sliding mode control and H∞/μ techniques. This scheme guarantees closed-loop system stability, and yields good performance and robustness in the presence of parametric uncertainties, time-delays and external disturbances as well. Also, it is shown that increasing the robustness to parametric uncertainties and time-delays does not lengthen the duration of the impulse sequence. Numerical examples are presented to verify the theoretical analysis.

scholarly journals Control Strategy of Photovoltaic Grid Connected System Based on PI and QPR Double Closed Loop Control

2021 ◽  
Vol 2136 (1) ◽  
pp. 012017
Author(s):  
Shengqing Li ◽  
Na Deng ◽  
Jian Zheng ◽  
Jiaxing Yu
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
System Stability ◽  
Closed Loop Control ◽  
Static Error ◽  
Loop Control ◽  
Phase Inverter ◽  
Suppression Effect ◽  
Three Phase ◽  
Three Phase Inverter

Abstract The traditional proportional integral (PI) controller in photovoltaic three-phase inverter system has the problems of no static error tracking and poor resonance suppression effect. In order to improve the resonance suppression effect and current control effect of photovoltaic three-phase inverter system, a control strategy of photovoltaic three-phase inverter system based on PI and quasi proportional resonance (QPR) double closed-loop control is proposed. The control strategy and control block diagram based on PI and QPR double closed-loop control are designed to realize no static error tracking of incoming current, which has better waveform of incoming current and resonance suppression effect, and improves system stability. Finally, the effectiveness of the control strategy are verified by simulation.

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