Design and Control of Rapid In-Air Reconfiguration for Modular Quadrotors With Full Controllable Degrees of Freedom

Abstract

This letter introduces a novel reconfigurable modular aerial robot capable of in-air self-disassembly and achieving full-actuation control. The proposed robot utilizes a unique modular design, each module incorporates a vector tilting structure and an active undocking mechanism. The design of the vector tilting structure amplifies the possibilities of control, allowing the introduced control algorithms to realize full-actuation control of the robot. The active undocking mechanism employs electromagnets for active and controllable reconfiguration. We redesigned the feedforward angle calculation and control assignment to enable the full-actuation controller in reconfigurable modular robots. Furthermore, we proposed a distributed framework to alleviate the burden on the communication system. Real-world experiments demonstrate that the reconfiguration process' ability to control maximum Euler angle oscillation within <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol {4\mathrm{^{\circ }}}$</tex-math></inline-formula> and reduce in-air reconfiguration time to under <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol {{\text{3}} \,\mathrm{s}}$</tex-math></inline-formula>. Additionally, experiments on full DoF hovering for both a single module and a reconfigurable robot confirm the stability of the proposed controller.