Control strategy for multiple capsule robots in intestine

Abstract

Based on the critical gap phenomenon of the intestinal capsule robot, a variable-diameter capsule robot with radial gap self-compensation is developed in this paper. With the functional variation principle, a fluid dynamic pressure model satisfying the boundary conditions of the outer surface of capsule robot with screw blades is derived. The critical gap phenomenon is studied theoretically and experimentally based on the end effect and the dynamic balance characteristics of the fluid on the surface of capsule robot. The concept of start-up rotation speed is defined, the relationship between the start-up rotation speed and the spiral parameters of capsule robot is investigated. The strategy for implementing drive and control on several capsule robots under the same rotational magnetic field is proposed, and by defining the start-up curves of several capsule robots with the similar motion regulation as the objective functions, genetic algorithm is employed to optimize the spiral parameters of several capsule robots. Experiments have shown that the proposed drive and control strategy for several capsule robots can be implemented effectively. It has a good prospect of application inside intestine to realize the drive and control on several capsule robots for different medical purposes.variable-diameter capsule robot, radial gap compensation, critical gap phenomenon, start-up rotation speed, multiple capsule robot control Citation:Zhang Y S, Wang D L, Ruan X Y, et al. Control strategy for multiple capsule robots in intestine.

Performance Evaluation of a Magnetically Driven Microrobot for Targeted Drug Delivery

“…In order to facilitate the calculation, pressure analysis is carried out only within one pitch range of the outer surface of microrobot. Since the pressure in the Y direction does not change, i.e., dP/dy = 0, according to the Reynolds equation, it can be obtained [24]:…”

“…As shown in Figure 4b, the targeted drug delivery microrobot locates in the uniform magnetic field generated by the three-axis Helmholtz coil, the coordinate system (OXYZ) is consolidated in its center, and n is the normal vector of the rotating magnetic field plane; α, β and γ are the included angles between n and the X axis, Y axis and Z axis, respectively, and n can be expressed as (cosα, cosβ, cosγ). The current driving method of the targeted drug delivery microrobot in the three-axis Helmholtz coil can be as follows [24]:…”

Development of Multiple Capsule Robots in Pipe

“…However, it is hard for magnetic fields to steer individual robots independently, because the drive frequencies of individual robots have the same range (i.e., one robot is out of control as the operator guides the other one, and they can only move in opposite directions). Zhang et al [ 27 ] studied the start-up curves of different robots and employed genetic algorithms to optimize screw structures to drive several capsule robots. However, the cooperative locomotion of multiple robots has not been implemented in the real world.…”

A Variable-Diameter Intestinal Capsule Robot Based on X Bars

“…Its disadvantage was rigid structure of robot body not to compensate itself's radial clearance. Zhang et al [7,8] researched the capsule robot widely and deeply based on three axes Helmholtz coils driven principle, studied radial clearance compensation , and obtained some achievement.…”