Springtail-inspired compliant hinge enables terrain-adaptable takeoff in insect-scale robots.

Area of Science:

• Biomechanics
• Robotics
• Evolutionary Biology

Background:

• Springtails (Collembola) exhibit remarkable millisecond-scale escape jumps using their furca.
• Furca length varies bimodally across 15 families, suggesting diverse jumping strategies.
• Previous research has not fully elucidated the biomechanical principles behind springtail jumping and furca morphology.

Purpose of the Study:

• To investigate the biomechanics of springtail escape jumps.
• To determine the role of furca morphology and joint compliance in jump performance.
• To translate biological principles into the design of a novel insect-scale jumping robot.

Main Methods:

• High-speed video and confocal imaging of springtail jumps.
• Analysis of furca length variation across taxonomic families.
• Development and testing of a biomimetic jumping robot with an elastic robo-furca hinge.

Main Results:

• Compliant, resilin-rich joints in long-furca springtails prolong push-off, suppress pitch, and bias takeoff forward.
• Rigid joints result in backward launches with rapid body rotation.
• The elastic robo-furca hinge significantly reduced body rotation (~90%) on flat ground compared to rigid designs.
• The robot maintained takeoff speed across varied terrains (gravel, leaves, etc.).

Conclusions:

• Furca joint compliance is crucial for controlled, forward-biased jumps in springtails.
• Biomimetic design of compliant hinges enables passive, terrain-adaptable locomotion in insect-scale robots.
• This research offers a pathway for developing robust, sensorless robots inspired by insect biomechanics.