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

Abstract

Developing small‐scale soft continuum robots with large‐angle steering capacity and high‐precision manipulation offers broad opportunities in various biomedical settings. However, existing continuum robots reach the bottleneck in actuation on account of the contradiction among small size, compliance actuation, large tender range, high precision, and small dynamic error. Herein, a 3D‐printed millimeter‐scale soft continuum robot with an ultrathin hollow skeleton wall (300 μm) and a large inner‐to‐outer ratio (0.8) is reported. After coating a thin ferromagnetic elastomer layer (≈100–150 μm), the proposed soft continuum robot equipped with hybrid actuation (tendon‐ and magnetic‐driven mode) achieves large‐angle (up to 100°) steering and high‐precision (low to 2 μm for static positioning) micromanipulation simultaneously. Specifically, the robot implements an ultralow dynamic tracking error of ≈10 μm, which is ≈30‐fold improved than the state of art. Combined with a microneedle/knife or nasopharyngeal swab, the robot reveals the potential for versatile biomedical applications, such as drug injection on the target tissue, diseased tissue ablation, and COVID‐19 nasopharyngeal sampling. The proposed millimeter‐scale soft continuum robot presents remarkable advances in large‐range and high‐precise actuation, which provides a new method for miniature continuum robot design and finds broad applications in biomedical engineering.

A Survey on Design, Actuation, Modeling, and Control of Continuum Robot

“…By integrating the pneumatic and tendon actuation methods, the robot exhibited great characteristics and achieved bending angles greater than 90 ° [65,66]. In order to achieve the interventional treatment of human stenosis, a continuum robot integrating magnetic-and tendondriven methods is proposed [51]. The robot can achieve relatively large angle steering under tendon actuation and highprecision position control of 10 μm under the external magnetic field.…”

Multicomponent and multifunctional integrated miniature soft robots

“…Medical catheter and guidewire technology place an important role in minimally invasive surgery which could reduce surgical risks and shorten recovery times. [160][161][162][163][164][165][166][167][168][169][170] The catheter-based interventions have a wide range of applications in the treatment of cardiovascular diseases. 6,100,164 In addition to delivering the catheter to the designated location, a variety of challenging tasks need to be accomplished, such as monitoring physiological environment (electrophysiological parameters, temperature, and pressure, etc), applying electrical or thermal stimulation to soft tissue, delivering therapeutic drugs and cells, embolization and clot removal.…”

Heat‐Mitigated Design and Lorentz Force‐Based Steering of an MRI‐Driven Microcatheter toward Minimally Invasive Surgery

“…Most commercial systems such as Sensei X and Magellan (Hansen Medical, Mountain View, CA, USA) use tendon‐based force transmission. [ 8 , 9 , 10 ] However, researchers have proposed many different alternative actuation mechanisms, such as multi‐backbone, [ 11 ] concentric tubes, [ 12 , 13 ] pneumatics, [ 14 ] smart materials, [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ] hydraulics, [ 22 , 23 , 24 , 25 , 26 , 27 ] magnetics, [ 28 , 29 , 30 , 31 , 32 , 33 ] or hybrid approaches [ 34 , 35 ] to overcome certain drawbacks of tendon‐based systems.…”