20 research outputs found
Self-Propelled Soft Everting Toroidal Robot for Navigation and Climbing in Confined Spaces
There are many spaces inaccessible to humans where robots could help deliver
sensors and equipment. Many of these spaces contain three-dimensional
passageways and uneven terrain that pose challenges for robot design and
control. Everting toroidal robots, which move via simultaneous eversion and
inversion of their body material, are promising for navigation in these types
of spaces. We present a novel soft everting toroidal robot that propels itself
using a motorized device inside an air-filled membrane. Our robot requires only
a single control signal to move, can conform to its environment, and can climb
vertically with a motor torque that is independent of the force used to brace
the robot against its environment. We derive and validate models of the forces
involved in its motion, and we demonstrate the robot's ability to navigate a
maze and climb a pipe.Comment: 7 pages and 8 figures. Accepted to IEEE Conference on Intelligent
Robots and Systems (IROS 2022). Video available at
https://youtu.be/R0TlKPLbM9
Soft Wrist Exosuit Actuated by Fabric Pneumatic Artificial Muscles
Recently, soft actuator-based exosuits have gained interest, due to their
high strength-to-weight ratio, inherent safety, and low cost. We present a
novel wrist exosuit actuated by fabric pneumatic artificial muscles that can
move the wrist in flexion/extension and ulnar/radial deviation. We derive a
model representing the torque exerted by the exosuit and introduce a
model-based optimization methodology for the selection of placement parameters
of the exosuit muscles. We evaluate the accuracy of the model by measuring the
exosuit torques throughout the full range of wrist flexion/extension. When
accounting for the displacement of the mounting points, the model predicts the
exosuit torque with a mean absolute error of 0.279 Nm, which is 26.1% of the
average measured torque. To explore the capabilities of the exosuit to move the
human body, we measure its range of motion on a passive human wrist; the
exosuit is able to achieve 55.0% of the active biological range in flexion,
69.1% in extension, 68.6% in ulnar deviation, and 68.4% in radial deviation.
Finally, we demonstrate the device controlling the passive human wrist to move
to a desired orientation in the flexion/extension plane and along a
two-degree-of-freedom trajectory.Comment: 16 pages, 15 figure
Haptic Guidance and Haptic Error Amplification in a Virtual Surgical Robotic Training Environment
Teleoperated robotic systems have introduced more intuitive control for
minimally invasive surgery, but the optimal method for training remains
unknown. Recent motor learning studies have demonstrated that exaggeration of
errors helps trainees learn to perform tasks with greater speed and accuracy.
We hypothesized that training in a force field that pushes the operator away
from a desired path would improve their performance on a virtual reality
ring-on-wire task.
Forty surgical novices trained under a no-force, guidance, or
error-amplifying force field over five days. Completion time, translational and
rotational path error, and combined error-time were evaluated under no force
field on the final day. The groups significantly differed in combined
error-time, with the guidance group performing the worst. Error-amplifying
field participants showed the most improvement and did not plateau in their
performance during training, suggesting that learning was still ongoing.
Guidance field participants had the worst performance on the final day,
confirming the guidance hypothesis. Participants with high initial path error
benefited more from guidance. Participants with high initial combined
error-time benefited more from guidance and error-amplifying force field
training. Our results suggest that error-amplifying and error-reducing haptic
training for robot-assisted telesurgery benefits trainees of different
abilities differently.Comment: 11 pages, 7 Figure, Under Revie
A database of marine phytoplankton abundance, biomass and species composition in Australian waters
There have been many individual phytoplankton datasets collected across Australia since the mid 1900s, but most are unavailable to the research community. We have searched archives, contacted researchers, and scanned the primary and grey literature to collate 3,621,847 records of marine phytoplankton species from Australian waters from 1844 to the present. Many of these are small datasets collected for local questions, but combined they provide over 170 years of data on phytoplankton communities in Australian waters. Units and taxonomy have been standardised, obviously erroneous data removed, and all metadata included. We have lodged this dataset with the Australian Ocean Data Network (http://portal.aodn.org.au/) allowing public access. The Australian Phytoplankton Database will be invaluable for global change studies, as it allows analysis of ecological indicators of climate change and eutrophication (e.g., changes in distribution; diatom:dinoflagellate ratios). In addition, the standardised conversion of abundance records to biomass provides modellers with quantifiable data to initialise and validate ecosystem models of lower marine trophic levels