Optimization-based Feedback Manipulation Through an Array of Ultrasonic Transducers

Abstract

In this paper we document a novel laboratory experimental platform for noncontact planar manipulation (positioning) of millimeter-scale objects using acoustic pressure. The manipulated objects are either floating on a water surface or rolling on a solid surface. The pressure field is shaped in real time through an 8-by-8 array (matrix) of ultrasonic transducers. The transducers are driven with square voltages whose phase-shifts are updated periodically every few milliseconds based on the difference between the desired and true (estimated from video) position. Numerical optimization is used within every period of a discrete-time feedback loop to determine the phase shifts for the voltages. The platform can be used as an affordable testbed for algorithms for non-contact manipulation through arrays of actuators as all the design and implementation details for the presented platform are shared with the public through a dedicated git repository. The platform can certainly be extended towards higher numbers of simultaneously yet independently manipulated objects and larger manipulation areas by the expanding the transducer array.

Acousto-Pi: An Opto-Acoustofluidic System Using Surface Acoustic Waves Controlled With Open-Source Electronics for Integrated In-Field Diagnostics

“…For instance, handheld acoustofluidics [35] to combat hurdles such as removing the need for benchtop lab equipment, miniaturizing and running the platform with battery power but capable of mixing liquids, nebulization and particle alignment. One system in particular uses a Raspberry Pi to interface ultrasonic transducers [36] that are used to position small scale objects on water or free moving on a surface, however the feedback processing is made on a separate laptop running MATLAB software. We have chosen Raspberry Pi as a platform for several reasons: compromise between performance and cost; ease of use and availability of Python libraries; possibility to interface and control hardware with the General Purpose Input Output (GPIO) pins; the desktop operating environment (similar to a PC); remote access; embedded signal processing; data storage and transmission to the cloud; and access to a dedicated family of hardware that is periodically upgraded.…”

4D Printing: Enabling Technology for Microrobotics Applications

“…The untethered microrobot is a microscale object that is moved or deformed by external force fields. These external force fields can take many forms, such as magnetic, [101][102][103][104] light, [105,106] acoustic, [107][108][109][110][111][112] etc. These mobile microrobots, ranging in size from a few tens of micrometers to few millimeters, allow them to be used in very small environments and enable very good mobility at high speeds.…”

3D Printing Hydrogel-Based Soft and Biohybrid Actuators: A Mini-Review on Fabrication Techniques, Applications, and Challenges

“…Similar to magnetic actuation, acoustic energy can be utilized to remotely manipulate micro/nano objects in fluid with high precision ( Matouš et al, 2019 ; Guo et al, 2016 ; Ozcelik et al, 2018 ; Ren et al, 2019 ; Tao et al, 2019 ; Fornell et al, 2019 ). Hydrogel structures that are acoustically stimulated at their resonant frequency can manipulate fluids for mixing ( Orbay et al, 2018 ) or generating fluid flow ( Kaynak et al, 2020 ).…”