Fig. 2: Collective modes within the frequency parameter space.
From: Microrobot collectives with reconfigurable morphologies, behaviors, and functions
a The external magnetic field \({{{{{\bf{B}}}}}}\) modulated in 2D space by the axial magnetic oscillation frequencies, where \({\theta }_{{{{{{\bf{B}}}}}}}\) is the orientation of \({{{{{\bf{B}}}}}}\) with respect to the x-axis. b Specific linear relationships between the two axial magnetic oscillation frequencies enables the different collective behaviors: Rotation (blue), static (red), oscillation (green), X chains (black), Y chains (gray), oscillating chains (cyan), gas-like mode containing self-propelling pairs, GaSPP (magenta). \({\Omega }_{x}\) and \({\Omega }_{y}\) are the oscillation frequencies of the external magnetic field along the \(x\) and \(y\) axes, respectively.
