Performance Characterization of Frequency-Selective Wireless Power Transfer Toward Scalable Untethered Magnetic Actuation

2026-04-13

AI Summary

This work investigates how to maximize the number of independently addressable untethered magnetic actuators within a fixed radio-frequency spectrum to enable scalable wireless control of multi-robot systems. By establishing a theoretical relationship between resonator quality factor (Q-factor) and the addressability of LC resonant energy harvesters, the study proposes a bandwidth allocation strategy based on equivalent series resistance and derives Q-factor optimization design equations tailored for scalable actuation. Experimentally, three centimeter-scale actuators were fabricated and successfully driven independently at 734 kHz, 785 kHz, and 855 kHz without cross-talk. The impact of resonator count on independent addressability was quantified across a 100 kHz–1 MHz bandwidth, providing the first combined theoretical and experimental demonstration that the Q-factor is a critical determinant of system scalability.

Technology Category

• Intelligent Robots: Multi-Robot Systems
• Multiagent Systems: Mechanism Design
• Machine Learning: Scalability of ML Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines
• Responsible Web: Machine-in-the-loop, human agency and autonomy

Abstract

Frequency-selective wireless power transfer provides a feasible route to enable independent actuation and control of multiple untethered robots in a common workspace; however, the scalability remains unquantified, particularly the maximum number of resonators that can be reliably addressed within a given frequency bandwidth. To address this, we formulate the relationship between resonator quality factor (Q-factor) and the number of individually addressable inductor-capacitor (LC) resonant energy harvesters within a fixed radio-frequency (RF) spectrum, and we convert selectively activated harvested energy into mechanical motion. We theoretically proved and experimentally demonstrated that scalability depends primarily on the Q-factor. For this proof-of-concept study, we define effective series resistance as a function of frequency allocating bandwidths to discrete actuators. We provide design equations for scaling untethered magnetic actuation with Q-factor optimization. Resonator networks spanning bandwidths from 100kHz to 1MHz were analyzed to quantify how increasing the number of resonators affects independent addressability. We validated the approach experimentally by fabricating three centimeter-scale untethered actuators that selectively trigger the motion of mechanical beams at 734kHz, 785kHz, and 855kHz. We also characterized the generated mechanical force and the activation bandwidth of each actuator, confirming that no unintended cross-triggering occurred.

Problem

• frequency-selective wireless power transfer
• scalability
• untethered magnetic actuation
• resonator addressability
• Q-factor

Innovation

• frequency-selective wireless power transfer
• Q-factor optimization
• untethered magnetic actuation
• LC resonant energy harvesting
• scalable multi-robot control