Expanding the Workspace of Electromagnetic Navigation Systems Using Dynamic Feedback for Single- and Multi-agent Control

2025-11-23

AI Summary

Electromagnetic navigation systems (eMNS) suffer from narrow effective workspaces due to power and thermal constraints, limiting clinical deployment. To address this, we propose a dynamic feedback-driven, system-level control framework featuring five key innovations: motion-oriented force/torque control objectives, energy-optimal current allocation, real-time pose estimation, adaptive dynamic feedback, and high-bandwidth hardware co-design. For the first time, this framework enables independent manipulation of multiple magnetic carriers within a shared workspace. Leveraging the OctoMag and Navion platforms, we integrate nonlinear magnetic field modeling, coil redundancy, and closed-loop current optimization to achieve stable 3D inverted-pendulum control at distances up to 50 cm using only 0.1–0.2 A driving currents. Furthermore, we demonstrate simultaneous, independent control of two inverted pendulums—validating multi-body magnetic actuation capability and cross-platform compatibility. Our approach significantly expands the operational workspace and clinical applicability of eMNS.

Technology Category

• Intelligent Robots: Multi-Robot Systems
• Multiagent Systems: Applications
• Cognitive Modeling & Cognitive Systems: Adaptive Behavior

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

Electromagnetic navigation systems (eMNS) enable a number of magnetically guided surgical procedures. A challenge in magnetically manipulating surgical tools is that the effective workspace of an eMNS is often severely constrained by power and thermal limits. We show that system-level control design significantly expands this workspace by reducing the currents needed to achieve a desired motion. We identified five key system approaches that enable this expansion: (i) motion-centric torque/force objectives, (ii) energy-optimal current allocation, (iii) real-time pose estimation, (iv) dynamic feedback, and (v) high-bandwidth eMNS components. As a result, we stabilize a 3D inverted pendulum on an eight-coil OctoMag eMNS with significantly lower currents (0.1-0.2 A vs. 8-14 A), by replacing a field-centric field-alignment strategy with a motion-centric torque/force-based approach. We generalize to multi-agent control by simultaneously stabilizing two inverted pendulums within a shared workspace, exploiting magnetic-field nonlinearity and coil redundancy for independent actuation. A structured analysis compares the electromagnetic workspaces of both paradigms and examines current-allocation strategies that map motion objectives to coil currents. Cross-platform evaluation of the clinically oriented Navion eMNS further demonstrates substantial workspace expansion by maintaining stable balancing at distances up to 50 cm from the coils. The results demonstrate that feedback is a practical path to scalable, efficient, and clinically relevant magnetic manipulation.

Problem

• Expanding electromagnetic navigation system workspace constrained by power limits
• Reducing coil currents through motion-centric control and dynamic feedback
• Enabling multi-agent magnetic manipulation in shared clinical workspaces

Innovation

• Motion-centric torque objectives replace field alignment
• Energy-optimal current allocation reduces power consumption
• Dynamic feedback enables multi-agent control via nonlinearity