Redundancy and overactuation in cephalopod-inspired soft robot arms

Area of Science:

• Robotics
• Biomimetics
• Mechanical Engineering

Background:

• Current soft robotic arms often adopt traditional hard-robot design principles.
• Minimalist actuator designs (three parallel longitudinal actuators) limit the soft arm design space.
• Cephalopod arms, inspiring soft robotics, feature numerous distributed muscle fiber bundles.

Purpose of the Study:

• Investigate performance implications of soft robotic arm architectures with many actuators (up to 12).
• Mimic the redundant and distributed nature of cephalopod appendages.
• Explore overactuation possibilities in soft robots.

Main Methods:

• Analysis of fluid-driven soft arm architectures using a generalizable simulation model.
• Construction and testing of a subset of examined many-actuator architectures.
• Investigation of non-circular cross-section designs, including elliptical.

Main Results:

• Many-actuator soft arms achieve higher strokes under equivalent load and pressure without sacrificing reach.
• These arms demonstrate quasi-omnidirectionality and constant-curvature turns with simple actuation.
• Non-circular cross-sections enable tunable load capacity and reach in multiple directions.

Conclusions:

• Overactuated, many-actuator soft arms significantly expand the design space for soft robots.
• These designs offer improved performance and novel tailoring options compared to minimalist arms.
• Biomimetic, distributed actuation offers a promising avenue for advanced soft robotic systems.