Hardware Sequencing of Inflatable Nonlinear Actuators for Autonomous Soft Robots

Area of Science:

• Robotics
• Materials Science

Background:

• Soft robots offer advantages over rigid robots for delicate interactions.
• Pneumatic actuators are preferred for soft robots due to safety and softness.
• Current pneumatic soft robots require individual pressure supplies and valves, leading to bulky tethering.

Purpose of the Study:

• To develop a method for controlling multiple actuators in soft robots without individual valves.
• To embed hardware intelligence in soft robots for sequential actuation.
• To demonstrate a practical application of this approach in a multi-degree-of-freedom soft robot.

Main Methods:

• Utilizing the interaction between nonlinear actuators and passive flow restrictions to program actuation sequences.
• Modeling the hardware sequencing mechanism.
• Implementing the approach on an 8-degree-of-freedom walking soft robot with two actuators per limb.

Main Results:

• Successfully demonstrated hardware-based sequential actuation for multiple pneumatic actuators.
• The 8-DOF walking robot achieved locomotion with payloads up to 800g.
• The robot reached travel speeds of 3 body lengths per minute.

Conclusions:

• The proposed method effectively embeds hardware intelligence in soft robots, enabling complex actuation sequences.
• This approach significantly reduces the need for complex on-board electronics and bulky tethers.
• The developed technique offers a practical solution for untethered, multi-DOF soft robotic systems.