Abstract
Capsule robot has emerged as a non-invasive and painless diagnostic tool for gastrointestinal examination. However, the growing demand for high-definition video and advanced functionalities significantly increases power consumption, while the capsule's compact size imposes stringent battery constraints. Wireless power transfer (WPT) offers a promising solution to overcome this energy bottleneck. This paper presents a wearable three-dimensional transmitting coil (3DTC) and a one dimensional receiving coil (1DRC) to enable omnidirectional and uninterrupted wireless charging for capsule robots. By acquiring attitude data from the capsule, the magnetic field of the wearable 3DTC is adaptively controlled to maximise receiving efficiency despite changes in the capsule's position and orientation. The capsule's built-in thermal and charging management circuits monitor the device's temperature, battery voltage, and stop charging when necessary to ensure safety. Beyond demonstrating a maximum received power of 1690 mW and a peak efficiency of 16.09%, this work further examines a range of practical challenges including, the effects upon the flexible coil bending in garment, charging robustness under various capsule motions, and thermal safety. These evaluations contribute to safer, more efficient, and more sustainable ingestible biomedical devices.