scholarly journals A Four-Stage Method for Active Control with Online Feedback Path Modelling Using Control Signal

2019 ◽  
Vol 9 (15) ◽  
pp. 2973
Author(s):  
Somanath Pradhan ◽  
Xiaojun Qiu ◽  
Jinchen Ji
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Control Signal ◽  
System Stability ◽  
Control Performance ◽  
Performance Simulation ◽  
Control Operation ◽  
Feedback Path ◽  
Path Modelling ◽  
Online Feedback

The presence of control signal feedback to the reference microphone in feedforward active control systems deteriorates the control performance. A four-stage method is proposed in this paper to carry out online feedback path modelling with the control signal. It consists of controller initialization, feedback path modelling using decorrelation filters, active control operation, and feedback path change detection for maintaining the control operation. In contrast to the existing auxiliary noise injection method, the proposed method uses five switches and three thresholds to control and maintain the system stability by avoiding the interference between control operation and feedback path modelling, and adaptive decorrelation filters are used to increase the feedback path modelling performance. Simulation results reveal that the proposed method is capable of tracking feedback path changes without injecting any auxiliary noise and maintaining the noise reduction performance and stability of the system.

Adaptive gain-order fractional control for network-based applications

2014 ◽  
Vol 17 (2) ◽  
Author(s):  
Inés Tejado ◽  
S. HosseinNia ◽  
Blas Vinagre
Keyword(s):  
Control Systems ◽  
Networked Control Systems ◽  
Adaptive Controller ◽  
System Stability ◽  
Switching Systems ◽  
Time Varying ◽  
Control Performance ◽  
Velocity Control ◽  
Fractional Control ◽  
Gain Scheduled

AbstractThis paper deals with the application of adaptive fractional order control to networked control systems (NCSs) to compensate the effects of time-varying network-induced delays. In essence, it adapts both the gains and the orders of a local PIαDμ controller in accordance with the current network condition in order to avoid a decreased control performance. A frequency domain framework is provided to analyze the system stability on the basis of the switching systems theory. The velocity control of a servomotor through the Internet is given to show the effectiveness of the proposed adaptive controller, including a comparison with non- and gain scheduled controllers.

Active Control of High Order Acoustical Modes in a Semi-Infinite Waveguide

1991 ◽  
Vol 113 (4) ◽  
pp. 523-531 ◽  
Author(s):  
J. D. Stell ◽  
R. J. Bernhard
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Noise Control ◽  
Active Noise Control ◽  
High Order ◽  
Control Methods ◽  
Control Performance ◽  
Secondary Sources ◽  
Active Noise ◽  
New Finding

This paper presents an analysis of the effectiveness of active noise control methods for control of high order modes in rigid-walled, semi-infinite waveguides. The waveguides examined in this investigation are terminated at one end with a rigid end. The case studies performed reconfirmed that n control actuators can control n propagating modes (including the plane wave) in a waveguide if the actuators are properly placed. The results also confirmed that the control actuators should be located at the node surfaces of the most significant evanescent modes to avoid various problems that evanescent modes cause active control systems. A significant new finding is the effect of the rigid waveguide termination on the active controller. The reflected energy from the termination causes standing waves in the region between the rigid termination and the secondary sources. At certain frequencies which correspond to resonant conditions, the standing wave amplitudes become large and the control actuator strength must be high. At these frequencies the effects of the evanescent modes become significant even when the mode is not close to its cut-on frequency. Similar resonant effects can be expected to affect active noise control performance for any case where there are significant reflections in the waveguide upstream of the control actuators.

Configuration of Control System for an Adaptive Tensegrity Structure

2010 ◽  
Author(s):  
Sinan Korkmaz ◽  
Nizar Bel Hadj Ali ◽  
Ian F. C. Smith
Keyword(s):  
Control System ◽  
Control Systems ◽  
Active Control ◽  
Damage Tolerance ◽  
Optimal Solution ◽  
Primary Concern ◽  
Control Performance ◽  
Tensegrity Structures ◽  
Damage Scenarios ◽  
Tolerance Strategy

Tensegrity structures are attractive due to their potential for deployability, ease of tuning and high precision control. Since tensegrity structures have highly coupled behavior, placement of actuators is a primary concern when designing active control systems. This study investigates the active control performance of cable members of a tensegrity bridge. The actuation efficiencies of cable members are evaluated through a multi-criteria approach. The configuration of the control system is thus identified through outranking candidate active members. A multi-objective damage tolerance strategy is then proposed and optimally directed control solutions are identified using stochastic search. Case studies for several damage scenarios are examined to validate results. The most efficient active cable configuration is compared with that needed for deployment. Results indicate that the control strategy for deployment is a near-optimal solution for damage tolerance.

Control of Vibration Using Compliant Actuators

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Sannia Mareta ◽  
Dunant Halim ◽  
Atanas A. Popov
Keyword(s):  
Vibration Control ◽  
Active Control ◽  
Passive Control ◽  
Performance Comparison ◽  
Control Performance ◽  
Frequency Bandwidth ◽  
Series Configuration ◽  
Compliant Actuators ◽  
Stiffness And Damping ◽  
Compliant Actuator

This work proposes a method for controlling vibration using compliant-based actuators. The compliant actuator combines a conventional actuator with elastic elements in a series configuration. The benefits of compliant actuators for vibration control applications, demonstrated in this work, are twofold: (i) vibration reduction over a wide frequency bandwidth by passive control means and (ii) improvement of vibration control performance when active control is applied using the compliant actuator. The vibration control performance is compared with the control performance achieved using the well-known vibration absorber and conventional rigid actuator systems. The performance comparison showed that the compliant actuator provided a better flexibility in achieving vibration control over a certain frequency bandwidth. The passive and active control characteristics of the compliant actuator are investigated, which shows that the control performance is highly dependent on the compliant stiffness parameter. The active control characteristics are analyzed by using the proportional-derivative (PD) control strategy which demonstrated the capability of effectively changing the respective effective stiffness and damping of the system. These attractive dual passive–active control characteristics are therefore advantageous for achieving an effective vibration control system, particularly for controlling the vibration over a specific wide frequency bandwidth.

Frequency Shaped Semi-Active Control for Magnetorheological Fluid-Based Vibration Control Systems

2013 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley ◽  
Gregory J. Hiemenz
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Active Control ◽  
Control Algorithm ◽  
Active Vibration Control ◽  
Control Algorithms ◽  
Model Parameters ◽  
Mr Fluid ◽  
Control Current ◽  
Active Vibration

Novel semi-active vibration controllers are developed in this study for magnetorheological (MR) fluid-based vibration control systems, including: (1) a band-pass frequency shaped semi-active control algorithm, (2) a narrow-band frequency shaped semi-active control algorithm. These semi-active vibration control algorithms designed without resorting to the implementation of an active vibration control algorithms upon which is superposed the energy dissipation constraint. These new Frequency Shaped Semi-active Control (FSSC) algorithms require neither an accurate damper (or actuator) model, nor system identification of damper model parameters for determining control current input. In the design procedure for the FSSC algorithms, the semi-active MR damper is not treated as an active force producing actuator, but rather is treated in the design process as a semi-active dissipative device. The control signal from the FSSC algorithms is a control current, and not a control force as is typically done for active controllers. In this study, two FSSC algorithms are formulated and performance of each is assessed via simulation. Performance of the FSSC vibration controllers is evaluated using a single-degree-of-freedom (DOF) MR fluid-based engine mount system. To better understand the control characteristics and advantages of the two FSSC algorithms, the vibration mitigation performance of a semi-active skyhook control algorithm, which is the classical semi-active controller used in base excitation problems, is compared to the two FSSC algorithms.

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