| The diagnosis and treatment of diseases in the alimentary canal have litter scar because of that the fiberscopes and videoscopes were widely used in clinic. The conventional endoscopes generate pains and discomfort to patients due to their stiffness and cannot reach to small intestines. The wireless capsule-type endoscope can overcome these shortcomings. However, the commercial capsule-type endoscopes move passively by peristaltic waves (and the gravity), which has limitation for doctors to diagnose more thoroughly and actively.In order to solve these problems, many kinds of driven method are proposed for wireless capsule-type endoscope system, such as, squirmy robot, inchworm-like microrobot, legal capsule, micro motor driving, electrical stimuli and magnetic field driving. The method of exterior driving magnetic field for locomotion in the gastrointestinal has been developed also for the capsule-type endoscope system, it has many advantages such as simple structure, easy controlling of speed and driving force, safety to human body, etc.A method of designing exterior coils which produce a reasonable magnetic field for driving the magnetic capsule-type endoscope is proposed in this thesis. According to the shape of the human body, the target magnetic field is decomposed in the cylindrical coordinates system. We obtain the relationship between current density and magnet field inversely by the target field method, and get the actual coil position and current sizes through discretization. A model is designed by this method, which is verified by FEA software. We analyze the feasibility of coils structure through comparing the calculative torque of the permanent magnet with ideal torque, analyzing the size of uniform magnetic field region. The result demonstrates that the permanent magnet capsule always can produce the uniform torque within the region of equipment inside.
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