Preventing stroke saturation of inertial actuators used for active vibration control of floor structures

Ahmadi, M. Wasi

doi:10.1002/stc.2546

Cited by 9 publications

(4 citation statements)

References 17 publications

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“…Nonetheless, when the dynamics of the system are considered, the unconditional stability assumption no longer holds and a limit to the control gain exists. Several techniques have been proposed to increase the stability margin of VF including: the Acceleration Feedback Control (Diaz and Reynolds, 2010), the Inner Control Loop Approach (Díaz et al, 2012a), the Integral Resonant Control (Díaz et al, 2012b), the Virtual Mass Technique (Mao et al, 2020), the adaptive reduction of VF gain (Ahmadi, 2020), or the Independent Modal Space Phase-Lead VF Control (Xue et al, 2022). The SISO VF schemes may perform poorly when the target structure exhibits closely-spaced modes.…”

Section: Introductionmentioning

confidence: 99%

Active control of human-induced vibrations on lightweight structures via electrodynamic actuator dynamics inversion

Ramírez-Senent

Gallegos-Calderón

García‐Palacios

et al. 2022

Journal of Vibration and Control

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The active vibration absorber represents an effective means to mitigate excessive vibrations in low-damping structures. Nevertheless, the dynamics of the actuators employed in such systems may negatively affect their performance and stability restricting their operational frequency range. This article presents an application of dynamics inversion techniques to the force control of electrodynamic proof-mass actuators employed as active vibration absorbers in lightweight pedestrian structures. The dynamics inversion approach is applied to enhance the classical direct velocity feedback scheme. Additionally, a novel method relying on dynamics inversion is presented: the Broadband Force Cancellation Algorithm. This procedure consists in estimating, in real-time, the equivalent force acting on the system to later apply it back to the structure with the opposed sign. The effectiveness of the proposed methods is assessed via numerical simulations carried over a realistic model of an existing lightweight footbridge and an electrodynamic proof-mass actuator. Two load cases are analyzed: a fixed swept-sine force and a walking load. Both cases account for the actuator-structure interaction. The human-structure interaction is considered in the latter scenario due to its importance when dealing with lightweight pedestrian structures. Simulation results demonstrate that the dynamics inversion techniques effectively cancel out actuator dynamics leading to an excellent tracking of the reference force output by the suggested or other vibration control algorithm. The proposed schemes are proved promising since they substantially outperform the widespread direct velocity feedback approach. In particular, the Broadband Force Cancellation Algorithm minimizes the action of the external forces within their estimation frequency range, thus being especially suited to tackle broadband excitations, important in lively pedestrian structures, whereas the velocity feedback methodology performs best at the structural resonant frequencies.

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Section: Introductionmentioning

confidence: 99%

Active control of human-induced vibrations on lightweight structures via electrodynamic actuator dynamics inversion

Ramírez-Senent

Gallegos-Calderón

García‐Palacios

et al. 2022

Journal of Vibration and Control

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“…When an force actuator is combined with a displacement or a velocity sensor as well as when a torque actuator is combined with an angular position or an angular velocity sensor, DVF can be simply used as the control law. 10 For collocated piezoelectric patches used as sensor and actuator, the open-loop transfer function has no high frequency roll-off. Therefore, PPF is often used as the control law to avoid high risk of spill-over at high frequency.…”

Section: Introductionmentioning

confidence: 99%

“…The choice of the control law for a system depends on the type of sensor/actuator leading to different shapes of the open‐loop transfer function in terms of pole/zero pattern. When an force actuator is combined with a displacement or a velocity sensor as well as when a torque actuator is combined with an angular position or an angular velocity sensor, DVF can be simply used as the control law 10 . For collocated piezoelectric patches used as sensor and actuator, the open‐loop transfer function has no high frequency roll‐off.…”

Section: Introductionmentioning

confidence: 99%

Design and optimization of a novel resonant control law using force feedback for vibration mitigation

Paknejad

Zhao

Chesné

et al. 2022

Structural Contr & Hlth

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Summary Integral‐force‐feedback (IFF) is a popular control law in active vibration damping of mechanical system when a force sensor is collocated with a force actuator. While it is simple, robust to resonance uncertainty and stable for any feedback gains, its efficiency is limited by system's parameters and in particular the stiffness ratio between the structure and the actuator. Therefore, the control authority decreases at high frequency resonances or when the actuator is weakly coupled to the structure. It has been shown that the use of double integrator with a real zero, named α‐controller, can improve the control authority of a target mode. However, this technique like IFF cannot be easily implemented in practice because of low frequency saturation issue induced by significantly amplifying the low frequency content during the integration process. This paper proposes a new control law, named resonant‐force‐feedback (RFF), based on a second order low pass filter to damp a target mode resonance. Through the mechanical analogy of the proposed system, RFF can be seen as an active realization of an inerter‐spring‐damper (ISD) system. In addition, the parameters of RFF are optimized based on two methods, that is, maximum damping criterion and H∞ optimization which consists in minimizing the settling time of the impulse response and the peak amplitude in the frequency domain, respectively. It is shown that RFF always provides a higher control authority of a target mode in comparison to IFF for a given stiffness ratio and in particular when the stiffness ratio is low. Despite the fact that the performance of the system, in terms of the closed‐loop damping ratio or the amplitude reduction, obtained by RFF is very close to that of α‐controller, RFF requires less control effort in comparison to α‐controller. The stability of the proposed system is also assessed in terms of the gain margin and the phase margin although the system is unconditionally stable. Moreover, the robustness of the designed RFF is compared to that of IFF under stiffness uncertainty. Although IFF can tolerate a higher level of uncertainty, the performance of RFF is superior to that of IFF for almost 50% of changes in the stiffness of the primary system.

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“…More recently, a double inner loop was proposed alongside the VFC, where one loop is a PD controller of the proof mass and the other loop adapts the velocity feedback gain depending on the value of the stroke [27]. A solution using linear methods, specifically a notch filter, was also discussed in [28].…”

Section: Introductionmentioning

confidence: 99%

Active nonlinear control of a stroke limited inertial actuator: Theory and experiment

Borgo

Tehrani

Elliott

2020

Journal of Sound and Vibration

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This paper presents a theoretical and experimental study of a stroke limited inertial actuator when used for active vibration control. The active control system under investigation consists of the inertial actuator attached to a flexible structure, a collocated vibration sensor and a velocity feedback controller (VFC). Controlling low frequency motions or large amplitude vibrations requires a very long stroke for the proof mass. However, a physical limitation of inertial actuators is that the stroke length is finite. Stroke saturation results in impulse-like excitation, which is transmitted to the structure and may result in damage. Additionally, these impacts between the proof mass and the end-stops can be in phase with the velocity of the structure, reducing the overall damping of the system, which leads to instability and limit cycle oscillations. This paper examines the implementation of a nonlinear feedback controller (NLFC) to avoid collisions of the proof mass with the actuator's end-stops, thus preventing this instability. The nonlinear control strategy actively increases the internal damping of the actuator when the proof mass approaches the end-stops. The experimental implementation of the NLFC is investigated for the control of the first mode of a cantilever beam, and it is shown that the robustness of the VFC system to external perturbations is much improved with the NLFC. It is shown experimentally that larger velocity feedback gains can be used without

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Preventing stroke saturation of inertial actuators used for active vibration control of floor structures

Cited by 9 publications

References 17 publications

Active control of human-induced vibrations on lightweight structures via electrodynamic actuator dynamics inversion

Active control of human-induced vibrations on lightweight structures via electrodynamic actuator dynamics inversion

Design and optimization of a novel resonant control law using force feedback for vibration mitigation

Active nonlinear control of a stroke limited inertial actuator: Theory and experiment

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