Collaborative Magnetic Manipulation Via Two Robotically-Actuated Permanent Magnets

Magnetically actuated robots have proven effective in several applications, specifically in medicine. However, gener- ating high actuating fields with a high degree of manipulability is still a challenge, especially when the application needs a large workspace to suitably cover a patient. The presented work discusses a novel approach for the control of magnetic field and field gradients using two robotically actuated permanent magnets. In this case, permanent magnets - relative to coil- based systems - have the advantage of larger field density without energy consumption. We demonstrate that collaborative manipulation of the two permanent magnets can introduce up to three additional Degrees of Freedom (DOFs) when compared to single permanent magnet approaches (five DOFs). We char- acterized the dual-arm system through the measurement of the fields and gradients, and show accurate open loop control with 13.5% mean error. We then demonstrate how the magnetic DOFs can be employed in magneto-mechanical manipulation, by controlling and measuring the wrench on two orthogonal magnets within the workspace, observing a maximum cross- talk of 6.1% and mean error of 11.1%.