scholarly journals An identification algorithm for feedback active control

2000 ◽  
Vol 22 (4) ◽  
pp. 193-204
Author(s):  
Nguyen Dong Anh
Keyword(s):  
Time Delay ◽  
Control Algorithm ◽  
Opposite Sign ◽  
Control Law ◽  
Identification Algorithm ◽  
Control Force ◽  
Practical Application ◽  
External Excitation ◽  
Time Duration ◽  
Computing Capacity

The aim of the paper is to present a control law for feedback active controlled structures in which a control algorithm is proposed to identify the external excitation with a time delay. The time duration in which the external excitation acts on the structure is devised into subintervals. In each subinterval the external excitation is identified and is then selected with the opposite sign as the control force for the next subinterval. The realization of the identification control algorithm in the practical application mainly depends on the computing capacity of the involved computer. and requires an investigation with respect to its robustness and stabilization.

scholarly journals Vibration Reduction of the Nonlinearly Tufted Carpet Yarn by a Modified Sliding Mode Control Method

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Shuang Huang ◽  
Xin Wu ◽  
Peixing Li
Keyword(s):  
Sliding Mode Control ◽  
High Frequency ◽  
Control Algorithm ◽  
Control Method ◽  
Sliding Mode ◽  
Control Law ◽  
Control Force ◽  
Fuzzy Sliding Mode Control ◽  
Mode Control ◽  
Fuzzy Sliding Mode

The yarn vibration causes the yarn tension value to fluctuate, causing a change in the amount of yarn feed, thus causing a deviation of the carpet pile height from the predetermined value. To solve this problem, the sliding mode control algorithm is used to design the sliding mode function and the sliding mode control law. And four variables in the yarn vibration system are controlled by the MATLAB software. For solving the chattering problem of the control law, the sliding mode control law is improved. The fuzzy sliding mode control algorithm based on the quasisliding mode is adopted. The results show that the sliding mode control algorithm is effective, but the sliding mode control force needs to be switched at high frequency and there is severe chattering. The fuzzy sliding mode control algorithm based on quasisliding mode is adopted to achieve better control effect with a smaller force. In addition, the control force does not have high-frequency switching, and the change is relatively stable, which reduces the chattering phenomenon of sliding mode control.

Predictive Control of a Laboratory Time Delay Process Experiment

2013 ◽  
Vol 11 (1) ◽  
pp. 29-36
Author(s):  
S. Enev
Keyword(s):  
Time Delay ◽  
Predictive Control ◽  
Control Algorithm ◽  
Optimization Problem ◽  
Problem Formulation ◽  
Practical Implementation ◽  
Control Law ◽  
Design And Implementation ◽  
Optimization Problem Formulation ◽  
Laboratory Time

Abstract The paper presents the design and implementation of a Model Predictive Control (MPC) scheme of a laboratory heatexchange process with a significant time delay in the input-output path. The optimization problem formulation is given and an MPC control algorithm is designed, achieving integral properties. Details, related to the practical implementation of the control law are discussed and the first experimental results are presented.

On a Theory of Swings

2002 ◽  
Vol 8 (3) ◽  
pp. 311-319 ◽  
Author(s):  
M. F. Dimentberg
Keyword(s):  
Opposite Sign ◽  
Damping Ratio ◽  
Temporal Variations ◽  
Direct Application ◽  
Control Law ◽  
Viscous Damping ◽  
Steady State Response ◽  
External Excitation ◽  
State Response ◽  
Oscillation Energy

The dynamics of a pendulum with controllable length, or swings, is considered. Possible variations of length are of bounded magnitude and arbitrary otherwise. A particular law of feedback-controlled stepwise variations, considered by Magnus to illustrate the basic swings effect, is shown to be the optimal one, as long as the goal is to maximize the growth rate of the energy of oscillations. Similarly, these temporal variations of length with the opposite sign, i.e. the “reversed swings” law, provide the maximal decay rate of the oscillation energy. The efficiency of the latter control law is predicted analytically for the case of a white-noise random external excitation of the pendulum, by calculating explicitly the expected steady-state response energy through direct application of Stochastic Differential Equations Calculus. For the case of a small bound R on relative variations of the length, the reversed swings effect is shown to be asymptotically equivalent to a linear viscous damping with damping ratio 3 R/π. Potential extensions of the considered control law are indicated, that is, of the “generalized reversed swings law”.

scholarly journals Influence of Time Delay on Controlling the Non-Linear Oscillations of a Rotating Blade

Symmetry ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 85
Author(s):  
Yasser Salah Hamed ◽  
Ali Kandil
Keyword(s):  
Time Delay ◽  
Natural Frequency ◽  
Multiple Scales ◽  
Control Process ◽  
Control Force ◽  
Specific Level ◽  
Loop Control ◽  
Positive Displacement ◽  
Non Linear ◽  
Linear Vibrations

Time delay is an obstacle in the way of actively controlling non-linear vibrations. In this paper, a rotating blade’s non-linear oscillations are reduced via a time-delayed non-linear saturation controller (NSC). This controller is excited by a positive displacement signal measured from the sensors on the blade, and its output is the suitable control force applied onto the actuators on the blade driving it to the desired minimum vibratory level. Based on the saturation phenomenon, the blade vibrations can be saturated at a specific level while the rest of the energy is transferred to the controller. This can be done by adjusting the controller natural frequency to be one half of the blade natural frequency. The whole behavior is governed by a system of first-order differential equations gained by the method of multiple scales. Different responses are included to show the influences of time delay on the closed-loop control process. Also, a good agreement can be noticed between the analytical curves and the numerically simulated ones.

scholarly journals Robust-adaptive dynamic programming-based time-delay control of autonomous ships under stochastic disturbances using an actor-critic learning algorithm

2021 ◽  
Author(s):  
Hossein Nejatbakhsh Esfahani ◽  
Rafal Szlapczynski
Keyword(s):  
Dynamic Programming ◽  
Time Delay ◽  
Control Algorithm ◽  
Approximate Dynamic Programming ◽  
Robust Adaptive Control ◽  
Stochastic Disturbances ◽  
Time Delay Control ◽  
Model Free ◽  
Delay Control ◽  
Robust Adaptive

AbstractThis paper proposes a hybrid robust-adaptive learning-based control scheme based on Approximate Dynamic Programming (ADP) for the tracking control of autonomous ship maneuvering. We adopt a Time-Delay Control (TDC) approach, which is known as a simple, practical, model free and roughly robust strategy, combined with an Actor-Critic Approximate Dynamic Programming (ACADP) algorithm as an adaptive part in the proposed hybrid control algorithm. Based on this integration, Actor-Critic Time-Delay Control (AC-TDC) is proposed. It offers a high-performance robust-adaptive control approach for path following of autonomous ships under deterministic and stochastic disturbances induced by the winds, waves, and ocean currents. Computer simulations have been conducted under two different conditions in terms of the deterministic and stochastic disturbances and all simulation results indicate an acceptable performance in tracking of paths for the proposed control algorithm in comparison with the conventional TDC approach.

Adaptive Dynamic Surface Control of Bouc–Wen Hysteretic Systems

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Mansour Peimani ◽  
Mohammad Javad Yazdanpanah ◽  
Naser Khaji
Keyword(s):  
Sliding Mode ◽  
Dynamic Surface Control ◽  
Lyapunov Theory ◽  
Hysteretic Behavior ◽  
Control Law ◽  
Structural Systems ◽  
Control Force ◽  
Dynamic Surface ◽  
Adaptive Dynamic ◽  
Surface Control

This paper develops an adaptive dynamic surface algorithm for designing the control law for uncertain hysteretic structural systems with seismic disturbances that can be converted to a semi strict feedback form. Hysteretic behavior is usually described by Bouc–Wen model for hysteretic structural systems like base isolation systems. Adaptive sliding mode and adaptive backstepping algorithms are also studied and simulated for comparison purposes. The presented simulation results indicate the effectiveness of the proposed control law in reducing displacement, velocity and acceleration responses of the structural system with acceptable control force. Moreover, using dynamic surface control (DSC), the study analyzes the stability of the controlled system based on the Lyapunov theory.

scholarly journals LQR Control of Wind Excited Benchmark Building Using Variable Stiffness Tuned Mass Damper

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
S. N. Deshmukh ◽  
N. K. Chandiramani
Keyword(s):  
Linear Time ◽  
Variable Stiffness ◽  
Tuned Mass Damper ◽  
Nonlinear Static Analysis ◽  
Performance Criteria ◽  
Control Law ◽  
Control Force ◽  
Displacement Control ◽  
Lqr Control ◽  
Mass Damper

LQR control of wind induced motion of a benchmark building is considered. The building is fitted with a semiactive variable stiffness tuned mass damper adapted from the literature. The nominal stiffness of the device corresponds to the fundamental frequency of the building and is included in the system matrix. This results in a linear time-invariant system, for which the desired control force is computed using LQR control. The control force thus computed is then realized by varying the device stiffness around its nominal value by using a simple control law. A nonlinear static analysis is performed in order to establish the range of linearity, in terms of the device (configuration) angle, for which the control law is valid. Results are obtained for the cases of zero and nonzero structural stiffness variation. The performance criteria evaluated show that the present method provides displacement control that is comparable with that of two existing controllers. The acceleration control, while not as good as that obtained with the existing active controller, is comparable or better than that obtained with the existing semiactive controller. By using substantially less power as well as control force, the present control yields comparable displacement control and reasonable acceleration control.

scholarly journals Nonlinear Aeroelastic System Identification Based on Neural Network

2018 ◽  
Vol 8 (10) ◽  
pp. 1916
Author(s):  
Bo Zhang ◽  
Jinglong Han ◽  
Haiwei Yun ◽  
Xiaomao Chen
Keyword(s):  
Neural Network ◽  
Time Delay ◽  
System Identification ◽  
Control Surface ◽  
Identification Algorithm ◽  
Aeroelastic System ◽  
Structural Nonlinearity ◽  
Time Marching ◽  
Artificial Neural Network Ann ◽  
Trained Neural Network

This paper focuses on the nonlinear aeroelastic system identification method based on an artificial neural network (ANN) that uses time-delay and feedback elements. A typical two-dimensional wing section with control surface is modelled to illustrate the proposed identification algorithm. The response of the system, which applies a sine-chirp input signal on the control surface, is computed by time-marching-integration. A time-delay recurrent neural network (TDRNN) is employed and trained to predict the pitch angle of the system. The chirp and sine excitation signals are used to verify the identified system. Estimation results of the trained neural network are compared with numerical simulation values. Two types of structural nonlinearity are studied, cubic-spring and friction. The results indicate that the TDRNN can approach the nonlinear aeroelastic system exactly.

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