Drive And Control Method Of Capsule Robot In Spatial Universal Rotating Magnetic Field

Medical invasive therapy features safe, reliable and painless. Swallowable capsule robots able to actively move inside the gastrointestinal tract will play certain important roles in such diagnosis, drug delivery, and even surgical operations, resulting in the reduction of hospitalization time and related health-care costs.In this paper, we propose a general scheme to drive the capsule robot screwed forward by a NdFeB actuator embedded inside the robot coupled with the spatial universal outer rotational magnetic field generated by three axes Helmholtz coils. Capsule micro robot prototype with clearance compensation has been designed, manufactured and tested, by discovery of the critical gap phenomenon with the spiral-type capsule micro robot inside intestine, aimed to significantly improve the driving ablility of capsule robot in bending pipe.The structure and swimming principle of diameter self-adaptive compliance robot is introduced. Applying variational principle, fluid dynamic pressure mathmatics model of capsule micro robot in pipeline environment is established on the basis of Renault and Navier-Stokes equation. Analytical formula of simplified fluid dynamic pressure on the surface of compliance robot is deduced. The radial dynamic balance equation and kinematics equation of the capsule robot are derived according to fluid dynamics.Theoretical analysis and experimental researchs on critical gap phenomenon of capsule robot are carried out, then we propose the concept of micro robot startup speed, to analyze laws of startup speed affected by spiral blade parameters, resulting in propose of drive and control method of multiple capsule robots in the same magnetic field. Aiming at the resemble laws of capsule robot startup speed curve, the Genetic Algorithm is applied to optimize multiple capsule micro robots.A general scheme to drive the capsule robot to move inside bending intestine is proposed., in which the capsule robot is screwed forward by a NdFeB actuator embedded inside the robot coupled with the spatial universal outer rotational magnetic field generated by three axes Helmholtz coils. According to vector addition and the theories of Helmholtz coils generate uniform magnetic field, three axes orthogonal square coil system applied alternating current provides uniform rotating magnetic field. Electromagnetic mathematical model of three axes thick walled Helmholtz is built, to analyze laws of electromagnetic quality be affected by coil configuration parameters. Three axes square Helmholtz coils are optimization desighed. Theoretical research and simulations show that the axial orientation of rotating magnetic field can be adjusted in response to the change of coordinate angle, and combined magnetic field has good uniformity and directivity.The technology for generating spatial universal rotating magnetic field provides a possible solution for the locomotion of capsule robot inside bending intestine, which makes it possible for capsule robot to realize endoscopic diagnosis and non-invasive therapy inside human body.