| The capsule robot is a specially designed swallowable capsule endoscope.The subject only needs to swallow the capsule robot,and through the continuous camera system inside the capsule robot,it can clearly take images of morphological characteristics of diseased tissues in organs such as the esophagus,stomach and small intestine,and transmit the collected images to outside the body.Doctors can make diagnosis based on the captured images,which is important for the diagnosis of early gastric and intestinal cancers.The capsule robot has the advantage of being minimally invasive and less painful to the patient during the examination,making it more acceptable to the patient than traditional gastroenteroscopy,which uses a tube inserted into the mouth or nasal cavity for examination.However,after capsule robots are swallowed into the human body,most of them can only rely on gastrointestinal peristalsis to travel through the human body organs for examination,which may result in missed diagnosis because the capsule robot fails to capture images of critical lesions.Therefore,active actuation of capsule robots is one of the important issues of current research.This topic studies the magnetic positioning and magnetic driving methods of capsule robot.Firstly,the magnetic fields generated by permanent magnets and electromagnetic coils are analyzed,and an integral model is established to describe the magnetic field distribution of permanent magnets and electromagnetic coils.Considering that the calculation formula of the integral model contains the integral equation which is difficult to calculate,the numerical integration method is used to simplify the integral equation and accelerate the calculation speed.The integral model is combined with the magnetic dipole model to establish the error function,and the particle swarm algorithm and L-M(Levenberg-Marquardt)algorithm are used to optimize the error function to realize the effect of individual permanent magnet positioning.Secondly,the electromagnetic coils are introduced to design the coil structure and driving method to achieve directional control of the capsule robot using magnetic moment at the central control point of the coil,and position control using magnetic force to drive the capsule to roll.When the external magnetic field is used to drive the capsule robot,the positioning accuracy of the permanent magnet is seriously affected,and the positioning results of the capsule robot cannot be used for position feedback.Therefore,based on the superposition principle,a permanent magnet positioning strategy under the influence of external driving magnetic field is proposed.The magnetic field strength of the electromagnetic coil at the magnetic sensor position is calculated,and the magnetic field of the electromagnetic coil is removed from the magnetic sensor measurement to obtain the exact magnetic field strength measurement at the permanent magnet,which is calculated using an optimization algorithm to achieve the magnetic positioning effect under the interference of the driving magnetic field.Finally,an active drive system for the capsule robot is built,consisting of a magnetic sensor array and an electromagnetic coil.The host computer program is designed on the PC,the software interface is designed using PyQt,the magnetic positioning and magnetic driving algorithms are run in the host computer,and the data are interacted with the embedded processor controlling the magnetic sensor array and the electromagnetic coil through the serial port.Design positioning experiments and drive experiments to verify the feasibility of the algorithms and achieve the active drive effect of the capsule robot. |
