Optimal Parametric Design Of A Spatial Universal Rotating Magnetic Field

With the development of wireless transmission system, micro medical capsule robot has achieved a breakthrough on the basis of it. The capsule robot of active driving detection can effectively realize the human gastrointestinal tract with security and efficacy at fixed point, will have an irreplaceable role in the gastrointestinal detection. Meantime, only a few capsule robots have been applied in clinical system, which still has some problems about energy supply and active control. Therefore, the problem that achieving better clinical application of capsule robot requires to be solved.Firstly, the actual magnetic flux density alternating components and the compensated current equations are introduced because of the mismatch between structural parameters and electrical parameters of the three pairs of Helmholtz coils. Then, according to the nonvisual movement of capsule robot, the bother and complexity of manipulating magnetic field and manipulated by a professional person, so the magnetic driving system based on the joystick is proposed. The direction of the rotation axes of the rotating magnetic field is controlled by the joystick to detect and observe orderly inside the intestinal environment according to the image feedback system. With the functions of tilting and rolling the bed, the robot is intelligently controlled, which lay the foundation for the clinical application of rotating magnetic field.Secondly, the energy of anyone of three coils balances with each other through the application of the concept of quality factor in the tri-axial Helmholtz coils is guaranteed. Considering the phase difference between current and voltage caused by inductance in each of three Helmholtz coils. The experiments have demonstrated that the mismatch between the structural coefficients of three pairs of Helmholtz coils and electrical parameters will cause the orientation errors on rotation axes of the rotating magnetic field. For eliminating the error of the amplitudes and the phases, a new technical scheme of spatial universal rotating magnetic field superimposed by feeding three sinusoidal currents to tri-axial Helmholtz coils is proposed in this paper, to analysis the influence rule of dynamic magnetic characteristics affected by electrical parameters which satisfies the conditions under which the same orientation angle of the three pairs of coils and matching the three different structural coefficients. The comprehensive evaluation function method for optimizing the coils' structure is presented based on two evaluation indexes including the active power and the total weight. The feasibility of the coils by studying the energy features between the magnetic field and the capsule robot is designed. In addition, the dynamic numerical equation of uniform magnetic field is derived and the homogeneous space of different dimension of Helmholtz coils is calculated.Finally, based on the new technical scheme of spatial universal rotating magnetic field, the Helmholtz coils that can accommodate the human body are designed. During the design of Helmholtz coils, comprehensively comparing the circle Helmholtz coils with the square ones, on the condition that their length, internal effective accommodation space and the alternating current are same, we obtain the results that compared to the circle coils. The magnetic flux density of three-axis square Helmholtz coils is larger, the uniformity is higher (approximately 1.1 times circle Helmholtz coils), and the power consumption is lower, The additional advantage is that the coils can be easily assembled, and the overall performance is better.