Fig. 4: Locomotion among bifurcating branches.
From: Adaptive wireless millirobotic locomotion into distal vasculature
a Snapshots for retrievable branch traversing among the bifurcation with angle θb of 60°. Only the leading forces and torques enabling the traversing are indicated on each time step. The composition of magnetic force-induced torque from Fmag, magnetic toque Tmag,zr, and reaction force-induced torque from Freact, bends and leads the robot into the desired branch. Scale bar: 4 mm. b Coordinate system and via-points discretization. c Strategies for branch traversing. d Experimental results of robot locomotion speed among various bifurcation angles in phantoms F – I from manual control and automatic trajectory (fmag = 0.5 Hz, lmag = 55 mm). The results are around 0.18 mm/s, the one acquired from phantom A. Thus, traversing among bifurcations does not sacrifice the locomotion speed. The data are presented as mean values ± standard deviation for the number of trials n = 5.
