Research On Physical Properties And Applications Of Triaxial Helmholtz Coils

Since a long period of time, bowel diseases have made patients suffer a lot. With the improvement of people’s living standard, the gastrointestinal medical robots with minimally invasive ability gradually come into sight. Many countries around the world have invested heavily on the research for this advanced medical equipment. Currently, study on capsule robots is developing from cable and passive driven towards the direction of wireless and active driven. The future successful use of capsule robots will make great sense in people’s life and will be a significant leap in the history of clinical.Based on the previous study about magnetically driven spiral-shaped capsule robot, this paper has researched the generating mechanism of space universal magnetic field, then analyzed its uniformity, and at last discussed its gradient. Through numerical analysis, the paper obtained a pulling force applied on the robot by the magnetic field. Then the paper explained the reason for the robot’s vibration and uncertainty of start direction according to the above force.From the point of energy, the paper analyzed the generation and distribution principle of magnetic field energy. And then the paper discussed the process of energy conversion between several forms of energy, they are electrical energy, thermal energy, magnetic energy and mechanical energy. Next, the paper analyzed the factors that may lead to changes of the magnetic field energy, and derived the theoretical expression of the magnetic field energy. According to magnetic energy theory, the paper also conducted the energy expression of magnetic moment applied on the robot.The size of the coil used in prior test is too small for patients to get through, which can only be used in some vitro experiments. In order to make the magnetic field generation device capable of future clinical trials, at the same time minimum its power consumption, the paper optimized the structural parameters of the coil through multi-objective optimization methods referred to the theory of ergonomics. A kind of large-size three-dimensional coil suitable for size of most patients has been designed.After finding the intestinal lesion location, the capsule robot has to release drug in the lesion site. In order to achieve this purpose, an additional mechanism has been designed inside the robot in this paper, so that the robot can complete the task of drug releasing. The main feature of this design is that the robot obtained an additional DOF relying on changes of the magnetic field strength, without installing any additional complex mechanism or power. So it becomes easy to realize the process of drug release. The paper also conducted a theoretical derivation about the torsional moment applied on drugs storage containers. Finally, we analyzed the stress in permanent magnets and drug containers with the finite element analysis software-Ansys.