Magnetically Actuated Millimeter-Scale Biped

TL;DR

This paper presents a magnetically actuated millimeter-scale biped robot, Big Foot, demonstrating its ability to perform stable gait, navigate complex terrains, and explore actuation schemes, providing a cost-effective platform for studying bipedal locomotion.

Contribution

The study introduces a miniature magnetically actuated biped robot and analyzes its gait stability and performance, comparing actuation schemes, which is a novel approach in bipedal robotics research.

Findings

Pure hip actuation successfully generates gait on uphill surfaces.

Heel Strike actuation offers better stability and faster gait.

Constant Pulse Wave actuation enables navigation on steeper slopes.

Abstract

This paper introduces a new approach to studying bipedal locomotion. The approach is based on magnetically actuated miniature robots. Building prototypes of bipedal locomotion machines has been very costly and overly complicated. We demonstrate that a magnetically actuated 0.3~gm robot, we call Big Foot, can be used to test fundamental ideas without necessitating very complex and expensive bipedal machines. We explore analytically and experimentally two age old questions in bipedal locomotion: 1. Can such robots be driven with pure hip actuation. 2. Is it better to use continuous or impulsive actuation schemes. First, a numerical model has been developed in order to study the dynamics and stability of a magnetically actuated miniature robot. We particularly focus on stability and performance metrics. Then, these results are tested using Big Foot. Pure hip actuation has been successful in generating gait on uphill surfaces. In addition, complex tasks such as following prescribed gait trajectories and navigating through a maze has been successfully performed by the experimental prototype. The nature and timing of hip torques are also studied. Two actuation schemes are used: Heel Strike Actuation and Constant Pulse Wave Actuation. With each scheme, we also vary the time duration of the applied magnetic field. Heel Strike actuation is found to have superior stability, more uniform gait generation, and faster locomotion than the Constant Pulse Wave option. But, Constant Pulse Wave achieves locomotion on steeper slopes.