Millimeter-Scale Soft Continuum Robots for Large-Angle and High-Precision Manipulation by Hybrid Actuation

Area of Science:

• Biomedical Engineering
• Robotics
• Materials Science

Background:

• Existing small-scale soft continuum robots face limitations in achieving simultaneous large-angle steering, high precision, and minimal dynamic error due to conflicting design constraints.
• The development of miniature robots for intricate biomedical procedures is hindered by the actuation challenges in current technologies.

Purpose of the Study:

• To design and develop a novel millimeter-scale soft continuum robot with enhanced actuation capabilities for biomedical applications.
• To overcome the limitations of existing continuum robots in terms of size, precision, and range of motion.

Main Methods:

• Fabrication of a 3D-printed millimeter-scale soft continuum robot featuring an ultrathin hollow skeleton (300 μm) and a high inner-to-outer ratio (0.8).
• Application of a thin ferromagnetic elastomer layer (100–150 μm) for hybrid actuation.
• Integration of tendon- and magnetic-driven modes for controlled movement.

Main Results:

• The robot achieved large-angle steering (up to 100°) and high-precision micromanipulation (static positioning accuracy of 2 μm).
• Demonstrated an ultralow dynamic tracking error of approximately 10 μm, representing a ~30-fold improvement over state-of-the-art robots.
• Successfully integrated with microneedles/knives and nasopharyngeal swabs for potential applications.

Conclusions:

• The developed millimeter-scale soft continuum robot offers significant advances in large-range and high-precision actuation, addressing key limitations in miniature robotic systems.
• This novel design provides a new approach for miniature continuum robot development with broad potential in drug delivery, tissue ablation, and diagnostic sampling.