Viscoelastic legs for open-loop control of gram-scale robots

Area of Science:

• Robotics
• Biomechanical Engineering
• Insect Locomotion

Background:

• Gram-scale robots face computational and resource limitations, hindering high-speed locomotion.
• Insects like cockroaches achieve robust running through inherent musculoskeletal mechanics.

Purpose of the Study:

• To investigate embedding control into leg mechanics for resource-constrained robots.
• To explore how material properties influence robot leg dynamics and locomotion.
• To reduce reliance on active control for stable, high-speed running in small robots.

Main Methods:

• Utilized a torque-driven damped spring-loaded inverted pendulum model for leg analysis.
• Developed design maps to analyze trade-offs between speed, efficiency, and stability.
• Experimentally tested magnetically actuated quadrupedal robots with viscoelastic legs.

Main Results:

• Tuning leg mechanics promotes high-speed, stable running with reduced active control.
• Design maps revealed performance trade-offs sensitive to leg properties and control inputs.
• Demonstrated experimental speeds up to 11.7 body lengths per second.

Conclusions:

• Embedding control into leg mechanics is a viable strategy for insect-scale robots.
• Material choice and mechanical tuning are crucial for optimizing robot locomotion.
• Bio-inspired mechanical design can overcome limitations in small, resource-constrained robots.