Self-Reconfiguring Robotic Gantries Powered by Modular Magnetic Lead Screws

Abstract

This paper outlines the design, specifications, and algorithms for a new modular self-reconfigurable robotic system; at its foundation is a novel modular magnetically geared linear actuator paired with a kinematic coupling connector. Motivating this work is the core idea that high performance actuators as well as inexpensive, precise and repeatable connectors are the key ingredients required for useful real-world self-reconfiguring machines. This work builds upon existing research in the areas of modular self-reconfigurable robots, magnetic lead screws, modular machine tools and kinematic couplings. Magnetic lead screws (MLS) have many desirable characteristics applicable to modular robots, including a tolerance for slight misalignments, high efficiency, zero backlash, robustness, inherent series elasticity, high force capability, and the ability to gracefully separate and reattach. Due to their high mechanical efficiency, MLS actuators are able to be combined in parallel to provide for increased forces and stiffness. Our system implements a MLS through two separable elements: brushless motor powered actuators called carts which pair with modular passive tracks which constrain the carts' movement to a line. This paper also explores the design for a connector which is able to precisely align modules through the use of a 4-way symmetric kinematic coupling.