Figure 4.

Simulation data of the rolling speed of the microrobots as a function of the distance between the bottom of the particle and the wall below

The microrobot is assumed to be horizontal. In one dataset, the particle rotates about its long axis with a fixed rotational frequency of 60 Hz at all distances and in the other dataset, the particle experiences a torque due to a magnetic field rotating with frequency 60 Hz; this frequency is above the step-out frequency when the particle is close to the wall because the rotational drag coefficient increases.