Microrobotic tentacles with spiral bending capability based on shape-engineered elastomeric microtubes

Abstract

Microscale soft-robots hold great promise as safe handlers of delicate micro-objects but their wider adoption requires micro-actuators with greater efficiency and ease-of-fabrication. Here we present an elastomeric microtube-based pneumatic actuator that can be extended into a microrobotic tentacle. We establish a new, direct peeling-based technique for building long and thin, highly deformable microtubes and a semi-analytical model for their shape-engineering. Using them in combination, we amplify the microtube’s pneumatically-driven bending into multi-turn inward spiraling. The resulting micro-tentacle exhibit spiraling with the final radius as small as ~185 μm and grabbing force of ~0.78 mN, rendering itself ideal for non-damaging manipulation of soft, fragile micro-objects. This spiraling tentacle-based grabbing modality, the direct peeling-enabled elastomeric microtube fabrication technique, and the concept of microtube shape-engineering are all unprecedented and will enrich the field of soft-robotics.

Mechanically Programmable Dip Molding of High Aspect Ratio Soft Actuator Arrays

“…These open face molds can be used to create functional soft robotic actuators that are mechanically programmed to bend in the same uniform direction or to bend in an arbitrary predefined vector field of directions. As mentioned earlier, actuators made from a form of dip coating have also been demonstrated by Paek et al [21] We extend these principles to achieve higher aspect ratio actuators as well as larger arrays of actuators. Through the use of modular open face mold forms, we are able to rapidly and inexpensively make new molds, various sizes, and custom arrangements of soft actuators.…”

“…In a prior demonstration of this mechanical programming strategy in the microtentacle created by Paek et al, the soft actuator was formed by curing rubber on a horizontal rod and later sealed after removal from the rod. [21] In this work, curing angles ranging from 5° to 60° offset from vertical successfully produced bending actuators, though we focused on 30° to 60°. The open face mold creates a sealed actuator tip while also pneumatically coupling the actuators to the rest of the array.…”

“…Once cured, the rod coating is removed, sealed on one end, and used as a soft pneumatic bending actuator. [21] The fabrication methods presented in this paper are most closely related to our dip coating method and expand it further to larger arrays, longer actuators, and additional strategies to mechanically program a bending motion into the actuators.…”

A multi-jointed underactuated robot hand with fluid-driven stretchable tubes

“…Excellent examples are the Multi-Choice Gripper [12], the Flexible Shape Gripper [13], the soft tentacles [14] and so on. However, the grasping force of these hands is too small to grasp a heavier object.…”

Development of a Multi-functional Soft Robot (SNUMAX) and Performance in RoboSoft Grand Challenge

“…There are a lot of different kinds of previous researches from continuum robots to soft robotic manipulators, and from micro scale to meter scale (Renda et al, 2012;Martinez et al, 2013;Paek et al, 2015;Ranzani et al, 2015). Also, there are efforts to control stiffness of the manipulator to improve versatility of continuum and soft manipulators (Jiang et al, 2012;Kim et al, 2013b;Santiago et al, 2015).…”