Designing a braille reader using the snap buckling of bistable magnetic shells

TL;DR

This paper presents a novel design for a braille dot actuator using bistable magnetic shells, combining simulations and experiments to achieve reversible, fast switching suitable for programmable braille readers.

Contribution

Introduces a new bistable magnetic shell design for braille dots, validated through simulations and experiments, enabling reversible and rapid state switching.

Findings

Design parameters meet geometric and force requirements

Magnetic actuation enables reversible bistability

Pneumatic loading facilitates state switching

Abstract

A design concept is introduced for the building block, a dot, of programmable braille readers utilizing bistable shell buckling, magnetic actuation, and pneumatic loading. The design process is guided by Finite Element simulations, which are initially validated through precision experiments conducted on a scaled-up, single-shell model system. Then, the simulations are leveraged to systematically explore the design space, adhering to the standardized geometric and physical specifications of braille systems. The findings demonstrate the feasibility of selecting design parameters that satisfy both geometric requirements and blocking forces under moderate magnetic fields, facilitated by pneumatic loading to switch between the two stable states. The advantages of the proposed design include the reversible bistability of the actuators and fast state-switching via a transient magnetic field. While the study is focused on experimentally validated numerical simulations, several manufacturing challenges that need to be resolved for future physical implementations are identified.