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Twisted-and-Coiled Actuators with Free Strokes Enable Soft Robots with Programmable Motions
Jiefeng Sun1, Brandon Tighe1, Yingxiang Liu2
1Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado, USA.
Soft Robotics
|June 26, 2020
Summary
Researchers developed advanced twisted-and-coiled actuators (TCAs) capable of 48% free stroke, enabling centimeter-scale soft robots to perform complex 3D motions like gripping and twisting for manipulation tasks.
Area of Science:
- Robotics
- Materials Science
- Mechanical Engineering
Background:
- Soft robots are typically actuated by pneumatics, cables, or dielectric elastomers.
- Twisted-and-coiled actuators (TCAs) offer a low-cost, high-work-density alternative for soft robotics.
- Conventional TCAs require preloading, limiting their motion capabilities to simple bending.
Purpose of the Study:
- To present an upgraded fabrication technique for TCAs enabling significant free stroke (contraction without preloading).
- To characterize the performance of these novel TCAs and the influence of fabrication parameters.
- To demonstrate the application of these enhanced TCAs in actuating centimeter-scale soft robots with programmable motions.
Main Methods:
- Fabrication of TCAs using an upgraded technique to achieve free strokes.
- Comparative static performance analysis of free-stroke TCAs versus conventional TCAs.
- Characterization of fabrication parameters' impact on TCA stroke and force.
- Demonstration of centimeter-scale soft robots actuated by free-stroke TCAs performing gripping, twisting, and 3D bending.
- Integration of motions to create a soft robotic arm for a pick-and-place task.
Main Results:
- The upgraded TCA fabrication technique yields a 48% free stroke capability.
- Free-stroke TCAs exhibit superior performance compared to conventionally fabricated TCAs.
- Fabrication parameters significantly influence the stroke and force output of TCAs.
- Demonstrated programmable motions including gripping, twisting, and 3D bending in centimeter-scale soft robots.
- A soft robotic arm capable of a pick-and-place task was successfully demonstrated.
Conclusions:
- Free-stroke TCAs overcome limitations of conventional TCAs, enabling complex 3D motions in soft robots.
- This advancement facilitates the development of miniature soft robots for diverse locomotion and manipulation applications.
- Electrically driven, free-stroke TCAs pave the way for untethered soft robots with onboard power and control.
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