Newly established three dimensional magnetically controlling system

Realizing the programmable motion of micro-nano robots in three-dimensional(3D) space, especially using magnetic fields [1], has promising application in biomedical science. However, in the micro-nano field, previous three-dimensional control methods have many limitations, and are much complicated, making it difficult to carry out practical applications. Based on the newly established spatial four-coordinate system (SFC), we build a system consist of four electromagnetic coils that can produce complex nonuniform magnetic fields, realizing the magnetic manipulation of a fully untethered dexterous micro-robotic device in 3D space. The system uses the least coils which increases the operating space and enables precise control of multiple degrees of freedom. Here, we designed a robot with three legs which can swim underwater using uniform field or move itself using gradient field achieving three-dimensional motion.