Bioinspired additive manufacturing material optimization for increased stiffness and improved strain sensing in...

Area of Science:

• Robotics
• Bio-inspired Engineering
• Materials Science

Background:

• Robots navigating complex terrain need accurate limb kinematics and force sensing for adaptive control.
• Current robotic limbs often use rigid segments and load cells, creating a trade-off between stiffness for kinematics and sensitivity for force sensing.
• Insects achieve this balance using heterogeneous exoskeletons with embedded strain sensors.

Purpose of the Study:

• To investigate localized Kevlar® fiber reinforcement in 3D printed robotic limbs.
• To balance structural stiffness for kinematics with strain sensitivity for force sensing, inspired by insect leg structures.
• To enhance the mechanical and sensing performance of robotic limbs through bio-inspired design.

Main Methods:

• Fabrication of 3D printed robotic limbs with varying degrees of Kevlar® fiber reinforcement (none, partial, full).
• Evaluation using beam bending, robot stepping, and fatigue tests to assess endpoint stiffness, strain sensitivity, and structural integrity.
• Analysis of localized reinforcement effects on mechanical properties and sensing capabilities.

Main Results:

• Partial Kevlar® fiber reinforcement effectively balanced limb stiffness and amplified strain signals, improving signal-to-noise ratio.
• Partially reinforced limbs exhibited superior fatigue resistance, maintaining sensing function after extensive cyclic loading.
• Localized, heterogeneous reinforcement mimics insect structures to enhance robotic limb performance.

Conclusions:

• Partial reinforcement is optimal for robotic limbs requiring both kinematic accuracy and sensitive force feedback.
• Bio-inspired heterogeneous reinforcement strategies can significantly improve robotic locomotion and sensing.
• This approach offers a pathway to more adaptable and robust robotic systems for challenging environments.