Design, Control, and Testing of Intelligent Electromagnetic Footwear for Astronautical Applications

This paper revisits a classic concept from science fiction, the electromagnetic shoe. The ability to effortlessly attach, detach, and walk in weightlessness would open up a wide range of quality-of-life improvements for astronauts during their everyday tasks inside upcoming large space habitats. To demonstrate this, a prototype shoe was developed and tested in microgravity under operational conditions on a parabolic flight. The key to the prototype’s functionality is for it to be solely controlled by natural human gait movements, allowing the user to walk without needing to focus on the system’s actuation. Therefore, the prototype entails a sensor package to measure each foot’s dynamics and deformation, allowing for accurate control of the electromagnets on the outside sole of the shoe. The sensor outputs are read and processed by a low-cost and low-power embedded system based around off-the-shelf microcontrollers, offering an extensive range of capabilities to the system that enable different control algorithms and the use of wireless communication between its components. Two control methods are proposed and investigated: a sensor-based state machine and a neural network approach, both running in real time onboard the on-shoe embedded microcontrollers. The system was tested successfully on the ground and during the conducted parabolic flight, providing an assessment of the prototype's performance, power efficiency, and user experience in standard-, low- and microgravity environments.