Intelligent controlling microbubble radial oscillations by using Slave–Master Feedback control

Behnia, S.; Yahyavi, Mohammad; Mobadersani, F.

doi:10.1016/j.amc.2014.07.104

Cited by 6 publications

(8 citation statements)

References 68 publications

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“…As compared to direct controllers [21]- [24], we used experimental data rather than idealized models of bubble dynamics to train the controller, which allowed us to incorporate effects of complex bubble behaviors, as indicated by the robust performance of the controller for a range of bubble concentrations (Fig. 6), and via feedback to account for nonmodelled system changes.…”

Section: Discussionmentioning

confidence: 99%

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Closed-Loop Spatial and Temporal Control of Cavitation Activity With Passive Acoustic Mapping

Patel

Schoen

Arvanitis

2019

IEEE Trans. Biomed. Eng.

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Ultrasonically actuated microbubble oscillations hold great promise for minimally invasive therapeutic interventions. While several preclinical studies have demonstrated the potential of this technology, real-time methods to control the amplitude and type of microbubble oscillations (stable vs inertial acoustic cavitation) and ensure that cavitation occurs within the targeted region are needed for their successful translation to the clinic. In this paper, we propose a real-time nonlinear state controller that uses specific frequency bands of the microbubble acoustic emissions (harmonic, ultra-harmonic, etc.) to control cavitation activity (observer states). To attain both spatial and temporal control of cavitation activity with high signal to noise ratio, we implement a controller using fast frequency-selective passive acoustic mapping (PAM) based on the angular spectrum approach. The controller includes safety states based on the recorded broadband signal level and is able to reduce sensing inaccuracies with the inclusion of multiple frequency bands. In its simplest implementation the controller uses the peak intensity of the passive acoustic maps, reconstructed using the 3 rd harmonic (4.896 ± 0.019 MHz) of the excitation frequency. Our results show that the proposed real-time nonlinear state controller based on PAM is able to reach the targeted level of observer state (harmonic emissions) in less than 6 seconds and remain within 10 % of tolerance for the duration of the experiment (45 seconds). Similar response was observed using the acoustic emissions from single element passive cavitation detection, albeit with higher susceptibility to background noise and lack of spatial information. Importantly, the proposed PAM-based controller was able to control cavitation activity with spatial selectivity when cavitation existed simultaneously in multiple regions. The robustness of the controller is demonstrated using a range of controller parameters, multiple observer states concurrently (harmonic, ultra-harmonic, and broadband), noise levels (−6 to 12 dB SNR), and bubble concentrations (0.3 to 180 × 10 3 bubbles per microliter). More research in this direction under preclinical and clinical conditions is warranted.

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Section: Discussionmentioning

confidence: 99%

“…closed loop controllers). An additional class of direct controllers are controllers based on chaos theory [23], [24], which unlike the above controllers have the advantage that they do not require knowledge of the system states.…”

Section: Introductionmentioning

confidence: 99%

Closed-Loop Spatial and Temporal Control of Cavitation Activity With Passive Acoustic Mapping

Patel

Schoen

Arvanitis

2019

IEEE Trans. Biomed. Eng.

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“…It is clear that the chaotic oscillations of UCA appeared by increasing the values of applied pressure, the microbubble demonstrates more chaotic oscillations as the pressure is intensifying (adapted from ref. [16]).…”

Section: Isolated Uca Microbubblementioning

confidence: 99%

“…The nonlinear nature of above theoretical models need specialized tools for analysis due to the fact that linear and analytical solutions are not enough. When the motion of bubbles or UCAs gets chaotic, their theoretically observed behaviors with chaos theory tools such as bifurcation and Lyapunov diagrams [15,16,17,18] have been studied. For this reason, it is substantial to have appropriate information about the microbubbles dynamics, for finding an acceptable stability region in various applications in industry.…”

mentioning

confidence: 99%

Association schemes perspective of microbubble cluster in ultrasonic fields

Behnia¹,

Yahyavi²,

Habibpourbisafar³

2018

Ultrasonics Sonochemistry

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Dynamics of a cluster of chaotic oscillators on a network are studied using coupled maps. By introducing the association schemes, we obtain coupling strength in the adjacency matrices form, which satisfies Markov matrices property. We remark that in general, the stability region of the cluster of oscillators at the synchronization state is characterized by Lyapunov exponent which can be defined based on the N-coupled map. As a detailed physical example, dynamics of microbubble cluster in an ultrasonic field are studied using coupled maps. Microbubble cluster dynamics have an indicative highly active nonlinear phenomenon, were not easy to be explained. In this paper, a cluster of microbubbles with a thin elastic shell based on the modified Keller-Herring equation in an ultrasonic field is demonstrated in the framework of the globally coupled map. On the other hand, a relation between the microbubble elements is replaced by a relation between the vertices. Based on this method, the stability region of microbubbles pulsations at complete synchronization state has been obtained analytically. In this way, distances between microbubbles as coupling strength play the crucial role. In the stability region, we thus observe that the problem of study of dynamics of N-microbubble oscillators reduce to that of a single microbubble. Therefore, the important parameters of the isolated microbubble such as applied pressure, driving frequency and the initial radius have effective behavior on the synchronization state.

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“…Lauterborn and his colleagues [43][44][45] have made great contributions by introducing the method of chaos physics to a model of a driven spherical gas bubble in water to determine its dynamic properties, especially its resonance behavior and bifurcation structure. Also, based on the previous works, the chaotic behavior of free bubbles observed both theoretically and experimentally [46][47][48][49][50], but this is not investigated for the case of UCAs, and it will be helpful to survey from this point of view because the method of chaos physics provides extensive knowledge about rich nonlinear dynamical systems. Moreover, neglecting liquid compressibility is not suitable for high-pressure amplitudes where the wall velocity of the agent is equal to the speed of sound in liquid [31], so the effects of liquid compressibility on the microbubble dynamics should be considered [40,41].…”

Section: Introductionmentioning

confidence: 99%

Numerical study on a polymer-shelled microbubble submerged in soft tissue

et al. 2020

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Ultrasound contrast agents have been recently utilized in therapeutical implementations for targeted delivery of pharmaceutical substances. Radial pulsations of the encapsulated microbubbles under the action of an ultrasound field are complex and high nonlinear, particularly for drug and gene delivery applications with high acoustic pressure amplitudes. The dynamics of a polymer-shelled agent are studied through applying the method of chaos physics whereas the effects of the outer medium compressibility and the shell were considered. The stability of the ultrasound contrast agent is examined by plotting the bifurcation diagrams, Lyapunov exponent, and time series over a wide range of variations of influential parameters. The findings of the study indicate that by tuning the shear modulus of surrounding medium and shell viscosity, the radial oscillations of microbubble cluster undergoes a chaotic unstable region as the amplitude and frequency of ultrasonic pulse are increased mainly due to the period doubling phenomenon. Furthermore, influences of various parameters which present a comprehensive view of the radial oscillations of the microbubble are quantitatively discussed with clear descriptions of the stable and unstable regions of the microbubble oscillations for typical therapeutic ultrasound pulses.

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Intelligent controlling microbubble radial oscillations by using Slave–Master Feedback control

Cited by 6 publications

References 68 publications

Closed-Loop Spatial and Temporal Control of Cavitation Activity With Passive Acoustic Mapping

Closed-Loop Spatial and Temporal Control of Cavitation Activity With Passive Acoustic Mapping

Association schemes perspective of microbubble cluster in ultrasonic fields

Numerical study on a polymer-shelled microbubble submerged in soft tissue

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