Redundancy and overactuation in cephalopod-inspired soft robot arms

Area of Science:

• Robotics
• Biomimetics
• Mechanical Engineering

Background:

• Current soft robotic arms often mimic traditional hard robot designs, using minimal actuators (three per segment) for omnidirectional bending.
• This minimalist approach, while efficient, limits the design space and doesn't fully leverage the potential of soft robotics.
• Cephalopod arms, with their numerous distributed muscle fibers, offer an alternative, more redundant and flexible model.

Purpose of the Study:

• To analyze fluid-driven soft robotic arm architectures with an increased number of actuators (up to 12).
• To investigate designs that mimic the distributed and redundant nature of cephalopod appendages.
• To explore the performance benefits of over-constrained designs in soft robots.

Main Methods:

• Utilized a previously developed generalizable model for simulating soft arm architectures.
• Analyzed designs with up to 12 actuators, considering over-constrained configurations.
• Constructed and tested a subset of the simulated many-actuator soft arm architectures.

Main Results:

• Many-actuator soft arms demonstrated higher stroke performance under equivalent load without compromising no-load reach.
• These advanced designs were capable of executing near constant-curvature turns using simple actuation patterns.
• The developed framework allows for cross-section variations not feasible in minimalist soft arm designs.

Conclusions:

• Soft robotic arms with a higher, distributed number of actuators, inspired by cephalopods, offer superior performance and design flexibility.
• Over-constrained designs are viable and beneficial in soft robotics due to their tolerance for conflicting constraints.
• This research expands the design possibilities for soft robotic arms, moving beyond traditional limitations.