Study On Structural Design Of Capsule Robot For Gastrointestinal Targeted Drug Delivery

Gastrointestinal diseases have become one of the most common diseases that threaten human health.Traditional gastrointestinal endoscopy has great damage to human body and is not acceptable.With the appearance of capsule robot,it opens the door of early detection and treatment of gastrointestinal diseases.The capsule robot enters the digestive tract orally by the patient,and the doctor can remotely control the capsule robot in the patient’s body to complete the examination,sampling,drug application,etc.,which not only reduces discomfort in the whole process,but also avoids cross infection and secondary injury.However,although the capsule robot has a good development prospect,how to accurately administer drugs and reduce drug residues has become an urgent problem to be solved.Based on the previous cooperation with Nankai Hospital and the actual needs of clinicians,a targeted drug application capsule robot was designed in this paper.The targeted drug application capsule robot uses the rotation of the threaded shell to generate power,and uses the external magnetic field to control the axial and radial rotation of the embedded single O-shaped radial permanent magnet to realize flexible movement and drug release in the intestine.Firstly,the electromagnetic drive system with three axes Helmholtz coil is analyzed,and the principle of magnetic field rotation was expounded,and the electromagnetic simulation was carried out to verify the movement and feasibility of the targeted drug application capsule robot.Secondly,the structure of the targeted drug application capsule robot is introduced,and the CAM mechanism,the overall motion and the principle of drug application of the capsule robot are expounded.The axial and radial motion of a single permanent magnet can switch two states of motion and application,realizing one input signal to control two output modes.Then,the motion analysis of the targeted drug application capsule robot was carried out.A dynamic model was established,two modes of motion and application were analyzed,and an energy conversion equation was constructed to optimize screw parameters in combination with the principle of screw mechanism in mechanical design basis,and verified by fluid simulation.Finally,the motion performance of the targeted drug application capsule robot was evaluated.The feasibility of optimizing the energy conversion rate of screw thread parameters was verified by the motion characteristic experiments of capsule robot with different parameters at different frequencies.Appropriate frequency and motion speed were selected to simulate medical tasks in human body,and the feasibility of two modes of motion control and drug application by a single permanent magnet was verified.Multiple targeted drug application to diseased areas was realized,providing technical support for the clinical application of capsule robot.