Locomotion Principles for Microrobots Based on Vibrations

Becker, Felix; Lysenko, Victor; Minchenya, V. T.; Kunze, Oliver; Zimmermann, Klaus

doi:10.1007/978-3-319-45387-3_9

Cited by 5 publications

(1 citation statement)

References 30 publications

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“…Piezoelectric bimorph actuators [1] are a popular choice for driving aerial [2][3][4][5], ambulatory [6][7][8][9][10], aquatic [11,12], and amphibious [13][14][15] micro-robotic platforms due to their high bandwidth [16], high power density [17], and favorable scaling to small sizes [18]. However, the lack of reliable motion sensors makes closed-loop control of these actuators in a servomotor-like scheme challenging.…”

Section: Introductionmentioning

confidence: 99%

Concomitant sensing and actuation for piezoelectric microrobots

Jayaram

Jafferis

Doshi

et al. 2018

Smart Mater. Struct.

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Sensor fabrication for microrobots is challenging due to their small size and low mass. As a potential solution, we present a technique for estimating the velocity of piezoelectric bending bimorph actuators, a popular choice for driving such microscale devices, that requires simple electronics and no additional mechanical components. Our approach relies on the insight that motion of the actuators causes varying strains on the surface on the piezoelectric material, which via the direct piezoelectric effect, results in a current proportional to the actuator velocity. We propose that the actuator be electrically approximated as a parallel combination of a frequency and voltage dependent resistor and capacitor, and a velocity proportional current source. We develop an experimental procedure to measure these quantities, and are able to experimentally determine the actuator tip velocity to within 10% accuracy over a range of voltages (25–200 V) and frequencies (1–2000 Hz, well beyond actuator resonance). We successfully apply this sensing methodology to two microrobots, the RoboBee and the Harvard Ambulatory MicroRobot (HAMR), to estimate the wing and limb motion respectively. We further use sensor feedback to close the loop on HAMR’s leg phase and obtain desired leg trajectories near transmission resonance. The proposed sensor methodology is generic and can be applied to piezoelectric actuators of different geometries and configurations for uses in microrobotic applications.

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Section: Introductionmentioning

confidence: 99%

Concomitant sensing and actuation for piezoelectric microrobots

Jayaram

Jafferis

Doshi

et al. 2018

Smart Mater. Struct.

View full text Add to dashboard Cite

show abstract

Dynamics and motion control of a capsule robot with an opposing spring

et al. 2019

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Real-time imaging and tracking of microrobots in tissues using ultrasound phase analysis

Pane

Iacovacci

Sinibaldi

et al. 2021

Applied Physics Letters

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Ultrasound B-mode imaging has been employed to monitor single agents and collective swarms of microrobots in-vitro and ex-vivo, in controlled experimental conditions. However, low contrast and spatial resolution still limit the effective employment of such method in a medical microrobotic scenario. Dopplerbased ultrasound appears as a promising tool for tracking microrobots in echogenic and dynamic environments as biological tissues. In this letter we demonstrate that microrobot displacements can be used as a special signature for their visualization within echogenic media, where B-mode fails. To this aim, we induced vibrations of a magnetic soft microrobot through alternated magnetic fields and used ultrasound phase analysis to derive microrobot features such as size and position over time. By exploiting vibrations, we were able to perform imaging and tracking of a low contrast microrobot both in tissuemimicking phantom and in chicken breast. Axial resolution was 38µm, that is four times smaller than the B-mode resolution with the employed equipment. We also performed real-time tracking of the microrobot's positions along linear trajectories with a linear velocity up to 1mm/s. Overall, the reported results pave the way to the application of the proposed approach for the robust monitoring of medical microrobots in tissue.

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Locomotion Principles for Microrobots Based on Vibrations

Cited by 5 publications

References 30 publications

Concomitant sensing and actuation for piezoelectric microrobots

Concomitant sensing and actuation for piezoelectric microrobots

Dynamics and motion control of a capsule robot with an opposing spring

Real-time imaging and tracking of microrobots in tissues using ultrasound phase analysis

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