Soft continuum manipulators, inspired by squid tentacles and elephant trunks, show promise in allowing robots to safely interact with complex environments. One ongoing problem for these manipulators is torsional stiffness, as continuum manipulators are naturally compliant and cannot actively resist torsional strain. A hybrid actuator that combines molded silicone actuators with 3D printed flexible wave springs is used to overcome this problem. It is shown that the inclusion of the 3D printed wave spring increases actuator torsional stiffness by up to a factor of 10. Further investigation of these structures is performed using both experimentation and simulation. Finally, this hybrid actuator design is used to create a nine‐degree‐of‐freedom soft continuum manipulator, which is used to perform a cantilevered pick‐and‐place task impossible for a traditional soft manipulator of similar size.
AFREEs: Active Fiber Reinforced Elastomeric Enclosures
Soft continuum manipulators provide a safe alternative to traditional rigid manipulators, because their bodies can absorb and distribute contact forces. Soft manipulators have near infinite potential degrees of freedom, but a limited number of control inputs. This underactuation means soft continuum manipulators often lack either the controllability or the dexterity to achieve desired tasks. In this work, we present an extension of McKibben actuators, which have well-known models, that increases the controllable degrees of freedom using active reconfiguration of the constraining fibers. These Active Fiber Reinforced Elastomeric Enclosures (AFREEs) preform some combination of length change and twisting, depending on the fiber configuration. Experimental results shows that by changing the fiber angles within a range of -30 to 30 degrees and actuating the resulting configuration between 10.3 kPa and 24.1 kPa, we can achieve twists between ± 60 degrees and displacements between -2 and 4 mm. By additionally controlling the fiber lengths and pressure, we can modify the AFREE kinematics further, creating dynamic behaviors and trajectories of actuation. The presented actuator creates the possibility to reconFigure actuator kinematics to meet desired soft robot motions.
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- Award ID(s):
- 1830163
- NSF-PAR ID:
- 10168490
- Date Published:
- Journal Name:
- IEEE International Conference on Soft Robotics (RoboSoft)
- Page Range / eLocation ID:
- 305 to 311
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/RoboSoft48309.2020.9115988
