Integrated Fully-Over Actuated Multi-electromagnet Collaborative Nonlinear Controller for Maglev Microgravity Experimental Capsule

The Maglev Microgravity Experimental Capsule (MMEC) possesses advantages such as high precision, low cost, and strong controllability, making it as a crucial scientific instrument for future ground-based microgravity experiments. However, the intricate coupling and collaboration among multiple electromagnets for levitation in MMEC are unexplored, and the impact of the varying number of electromagnets on the control system, along with the significant mass changes and interference from the separation/combination of internal and external capsules in the microgravity phase, pose challenges to its microgravity performance improvement. To address these issues, this study proposes an Integrated Fully-Over Actuated Multi-electromagnet Collaborative Nonlinear (MCN) Controller. By leveraging the established comprehensive state-extended nonlinear model of MMEC and analyzing the relationships among multiple electromagnets, this controller enables effective control of fully-actuated and over-actuated systems, addressing the challenge posed by the variable number of electromagnets resulting from payload fluctuations. A stability analysis for capsule separation and combination in the microgravity phase is also carried out to overcome the issues of sudden mass changes and external interference. Experiments on a ground-based platform verify the effectiveness of the proposed method, providing a theoretical basis and practical experience for enhancing MMEC’s microgravity performance.