Acoustic Power Management by Swarms of Microscopic Robots

TL;DR

This paper analyzes how microscopic robots can harvest ultrasound energy within the body, addressing power limitations due to tissue attenuation and proposing swarm-based management to optimize energy collection.

Contribution

It introduces a collective energy management strategy for swarms of microscopic robots to mitigate tissue attenuation and optimize power harvesting.

Findings

Hundreds of picowatts can be delivered to a robot within 10cm in low-attenuation tissue.

Power decreases significantly in high-attenuation tissues like lungs.

Swarm coordination can maintain sufficient energy levels despite tissue attenuation.

Abstract

Microscopic robots in the body could harvest energy from ultrasound to provide on-board control of autonomous behaviors such as measuring and communicating diagnostic information and precisely delivering drugs. This paper evaluates the acoustic power available to micron-size robots that collect energy using pistons. Acoustic attenuation and viscous drag on the pistons are the major limitations on the available power. Frequencies around 100kHz can deliver hundreds of picowatts to a robot in low-attenuation tissue within about 10cm of transducers on the skin, but much less in high-attenuation tissue such as a lung. However, applications of microscopic robots could involve such large numbers that the robots significantly increase attenuation, thereby reducing power for robots deep in the body. This paper describes how robots can collectively manage where and when they harvest energy to mitigate this attenuation so that a swarm of a few hundred billion robots can provide tens of picowatts to each robot, on average.