Independent Control of Two Magnetic Robots using External Permanent Magnets: A Feasibility Study

The ability to have multiple magnetic robots operate independently in the

same workspace would increase the clinical potential of these systems allowing

collaborative operation. In this work, we investigate the feasibility of

actuating two magnetic robots operating within the same workspace using

external permanent magnets. Unlike actuation systems based on pairs of

electromagnetic coils, the use of multiple permanent magnets comes with the

advantage of a large workspace which better suits the clinical setting. In this

work, we present an optimization routine capable of generating the required

poses for the external magnets in order to control the position and orientation

of two magnetic robots. We show that at a distance of 15cm, minimal coupling

between the magnetic robots can be achieved (3.9\% crosstalk) each embedded

with 5mm diameter, 5mm length NdFeB magnets. At smaller distances, we observe

that the ability to independently control the robot torques decreases, but

forces can still achieve independent control even with alignment of the robots.

We test our developed control system in a simulation of two magnetic robots

following pre-planned trajectories in close proximity (60 mm) showing a mean

positional error of 8.7 mm and mean angular error of 16.7 degrees.