A Novel and Compatible Sensing Coil for a Capsule in Wireless Capsule Endoscopy for Real Time Localization

Abstract—Three orthogonal sensing-coils for six degrees of freedom (DOF) localization, translation (x, y, z) and rotation (α, β, γ), are designed and experimentally verified. The sensing method is intended for the use in Wireless Capsule Endoscopy (WCE). The coils are rectangular-shaped rather than conven-tional cylindrical and are compatible with existing commercial WCE capsules. The rectangular-shaped coils require less space but provide a larger area to induce higher voltages, which consequently increases the sensing range. They can also be used for locomotion and wireless power harvesting. Three orthogonal transmitting-coils (9.5 cm in diameter and with 60 turns are used to generate electromagnetic fields. They are energized sequentially with a 0.6A sinusoidal wave of 7.7 kHz. Non-linear relationships are developed between the induced voltages in the sensing-coils and the six variables (x, y, z, α, β, γ) which are estimated with a non-linear solver. I