Research On Driving Power Of Medical Micro Robot With Rotating Magnetic Field

Micro robot has the haracteristic of minor injury, painless and quick response, wireless micro in-pipe swimming robot controlled by external magnetic Field has a widespread prospect for applying in medical engineering. Direct Digital frequency Synthesis was advanced rapidly in early 1970s and has been developing owing to its entirely digital structure. With the two technologies and the flexible control ability of MCU, a new external rotating magnetic field driving power system based on Direct Digital frequency Synthesis technology is been developed. This system can produce a rotating magnetic field in a plane by drive two sets of Helmholtz windings, used to drive the wireless micro in-pipe swimming robot. The paper made a detailed introduction about design method and process of the system.Firstly, the paper present on the driving and the swimming mechanism of the micro robot, proposes a wireless driving method to actuate the capsule micro robot to swim by using a rotating magnetic field as the exterior driving magnetic field, which is produced by two sets of Helmholtz windings that is drived by two in quadrature current signal, the micro robot has a spiral structure and a permanent magnetic inner driver of NdFeB embedded in it.The development courses and characteristics of frequency Synthesis are presented in this paper, and this paper also introduces the principle and structure of DDS chip AD9854,it mainly depicts the hardware's and software's realization of the rotating magnetic field driving power, and designed a digital control magnetic field driving power Which is based on the AT89S52 and DDS chip AD9854 to drive two sets of Helmholtz windings. The hardware of the rotating magnetic field driving power consists of three blocks, those are signal generation module based on AD9854, low pass filter and amplifying circuit module, keyboard and LCD display module, and this paper designed each several part circuit of the system, at last the system can produce two in quadrature current signal to drive two sets of Helmholtz windings.By the systems debug and analysis, it has been proved that digital control rotate magnetic field system meet the subject's requirement, and this system have many advantages ,such as small in size, extremely accurate, handled easily, response quickly, which provides the basis for micro robot applying in medical engineering.