Dual-Arm Platform for Control of Magnetically Actuated Soft Robots

Abstract

The present work discusses a novel approach for remote magnetic actuation. In the following, we present a full characterization of the dual External Permanent Magnet (dEPM) actuation system. Herein, we discuss how this system can be applied to fully control the magnetic field in a predefined workspace. We discuss how it can generate a homogeneous magnetic field, in every direc- tion and control every independent gradient in the same workspace. We prove how up to 8 Degrees of Freedom (DOF), 3 independent field components and 5 gradients directions, can be controlled fully independently. The rise in popularity of magnetic actuation comes from the fact that it allows for the control of wireless magnetic micro-robots and magnetic Soft Continuum Robots (SCRs), which bring about a reduction in size when compared to their non-magnetic counterparts. SCRs have a theoretical infinite number of DOFs and thus, can adapt to various nonlinear environments, min- imising contact and pressure on surrounding tissue. While successful multi-DOFs magnetic actuation has been demonstrated at small scale [1], by using systems of coils, large-scale manipulation is yet to be fully proven. In fact, it might require several independently- controlled coils [2] to be effective along any possible direction of motion. Despite their ability to generate both homogeneous fields [3] and gradients [2], systems of coils are less scalable, compared to permanent magnet- based magnetic field control systems [3]. In fact, due to lower field density, energy-consumption and need for high-performance cooling systems, they are generally characterized by limited workspace [4]. By further developing the idea of remotely actuating 1 Internal Permanent Magnet (IPM) (internal since, generally, inside the human body) with 1 External Per- manent Magnet (EPM) [5], we discuss how 2 robotically actuated EPMs are able to magnetically manipulate 2 IPMs, independently. This is achieved by independently controlling the torque (magnetic field) and the force (field gradients) applied to each IPM.