Deflected Versus Preshaped Soft Pneumatic Actuators: A Design and Performance Analysis Toward Reliable Soft Robots

Area of Science:

• Robotics
• Materials Science
• Mechanical Engineering

Background:

• Soft pneumatic actuators (SPAs) are crucial for soft robot motion but susceptible to defects.
• Defects in SPAs can cause stress concentrations and inconsistent performance, impacting reliability.

Purpose of the Study:

• To model and characterize SPA performance with varying chamber shapes and geometries.
• To compare SPA expansion consistency, repeatability, and stress under different conditions.
• To establish design principles for enhancing SPA reliability.

Main Methods:

• Modeling and characterization of SPAs with different chamber shapes (straight, helical) and cross-sections (squared, circular).
• Analysis of SPA performance under variable loading conditions.
• Comparison of expansion homogeneity, repeatability, and time-wise consistency.

Main Results:

• Straight chambers in SPAs exhibit high repeatability (0.06 mm deviation) and significantly lower stress.
• Preshaped helical chambers offer 500% more homogeneous and 300% more efficient expansion than deflected ones.
• Squared cross-sections provide over 1000 times more time-wise consistent expansion than circular ones.

Conclusions:

• SPAs with lower potential energy or less susceptibility to its effects are more reliable.
• Design principles derived from this study help mitigate common SPA reliability issues.
• Informed design decisions before fabrication are key to improving soft robot reliability.