Unified Magnetic 5-DoF Localization Framework for Capsule Robots Via PMMN-DBO: From Single to Multi-Robot Scenarios with Real-Time Control–Localization Co-Design
Zijin Zeng, Chan Li, Zaiyang Chen, Shunxiao Huang, Wenyan Niu, Hongyan Sun, Menglu Tan, Yingjian Guo
Abstract
Motivated by clinical needs for precise navigation and safety, low-latency and high-precision localization has become a key enabler for capsule robots. A unified magnetic 5-DoF high-precision localization framework for capsule robots is presented. Building on layered multi-source magnetic field modeling, online external-field compensation, and global optimization-based inversion, the framework achieves real-time decoupling between control and localization fields, while providing a unified interface compatible with diverse hardware configurations and operation modes. On this basis, the PMMN-DBO algorithm is proposed, delivering high-accuracy and efficient localization in single- and multi-capsule scenarios, and supports synchronized control–localization. Experimentally, for single-capsule localization, mean errors are 0.59 mm/0.69° with a 20.2 ms computation time, surpassing conventional methods. In multi-capsule settings, localization errors remain low with stable convergence: mean errors are 1.28 mm/1.13° for two capsules and 2.56 mm/2.83° for three capsules. Under synchronized control–localization, trajectory-tracking errors reach 1.33 mm/1.85°. Overall, the proposed framework is unified, high-precision, efficient, and flexible, laying a general and reusable foundation for clinical-grade precise navigation and closed-loop magnetic control.