An 88-milligram insect-scale autonomous crawling robot driven by a catalytic artificial muscle

Area of Science:

• Robotics and Micro-engineering
• Materials Science
• Chemical Engineering

Background:

• Autonomous microrobots face challenges due to low energy density of batteries, limiting untethered operation.
• Existing microrobots often rely on external power sources, hindering complex behaviors and mobility.
• High specific energy fuels are needed to match biological systems and enable sustained microrobot function.

Purpose of the Study:

• To design and build an autonomous, subgram microrobot capable of complex behaviors.
• To overcome the power limitations of current microrobots using a novel fuel source.
• To demonstrate untethered locomotion and functionality in various environments.

Main Methods:

• Developed RoBeetle, an 88-milligram insect-sized robot powered by catalytic combustion of methanol.
• Integrated NiTi-Pt-based catalytic artificial micromuscles with a millimeter-scale mechanical control mechanism (MCM).
• Characterized thermomechanical properties of artificial muscles and optimized MCM design through tethered experiments.

Main Results:

• Achieved autonomous crawling using methanol as fuel, offering high specific energy (20 MJ/kg).
• Demonstrated successful locomotion tests including crawling on rough surfaces, climbing inclines, and payload transportation.
• Validated the robot's functionality and performance in diverse conditions, including outdoor environments.

Conclusions:

• RoBeetle represents a significant advancement in autonomous microrobotics, powered by a high-energy-density fuel.
• The developed artificial micromuscle and MCM system enables untethered, complex robotic behaviors.
• This work paves the way for future microrobots with enhanced mobility and operational capabilities.