Simulation and experimental studies of a vibro-impact capsule system driven by an external magnetic field

Abstract

This paper studies the electromagnetic field used for driving a vibro-impact capsule prototype for small bowel endoscopy. Mathematical models of the electromagnetic field and the capsule system are introduced, and analytical solution of the magnetic force applied on the capsule is derived and verified by experiment. The impact force between the inner mass of the capsule and the capsule body is also compared via numerical simulation and experimental testing. By comparing the capsule’s progressions under different control parameters (e.g. the excitation frequency and duty cycle), the merits of using the vibro-impact propulsion are revealed. Based on the experimental results, the optimised speed of the prototype can achieve up to 3.85 mm/s. It is therefore that the potential feasibility of using the external electromagnetic field for propelling the vibro-impact capsule system is validated.

A Dielectric Elastomer Actuator-Driven Vibro-Impact Crawling Robot

“…It is worth noting that our robot has a peak velocity of 0.71 BL/s. Compared with the vibro-impact robots reported in the literature [ 28 , 30 , 51 , 52 , 53 ], the proposed robot has a clear advantage in its maximum velocity, which offers potential advantages in applications such as disaster search and rescue. In addition, it is noteworthy that when D = 1.6 mm, the robot exhibits noticeable backward locomotion near the impact frequency band, as highlighted in the red box in Figure 9 d. At 73 Hz, the maximum backward velocity of the robot reaches 16.9 mm/s.…”

Design and Experimental Investigation of a Vibro-Impact Capsule Robot for Colonoscopy

“…The dynamic behaviour of the robot will be greatly affected by its complex environmental conditions, such as in the intestinal tract [20]. A miniaturised capsule prototype adopting external magnetic actuation was studied in [21]. Earlier studies on vibrational capsule [22] revealed that vibrations could be a potential means to reduce capsule-intestine resistances.…”

“…As a successive design adopted from [21], the main contributions of this work are summarised as follows. (1) The focus of this letter is to demonstrate the effectiveness of using vibro-impact method to drive the capsule robot for colonoscopy.…”

“…Thus an external electromagnet system was developed to control the robot's internal permanent magnet (IPM). (2) The external coil in this design was placed on top of the capsule, rather than in front of the capsule as studied in [21]. By doing this the coil can be flexibly placed along the patient's abdomen, either above or beneath the capsule robot; while in the previous design, the coil should be strictly placed at the concentric position of the capsule which is difficult to maneuver.…”

Dynamic and steady-state performance analysis of a linear solenoid parallel elastic actuator (LSPEA) with nonlinear stiffness

“…MMAs adopt permanent magnets as movers, with compact structures and high power density. Zhang et al [20] introduced nonlinear models of the electromagnetic field and capsule system based on the Biot-Savart law and Charge model. Qin et al [21] established the dynamic model of a magnetic micromirror based on the Lorentz force on the mover.…”