6,941 research outputs found
Discrete Cosserat Approach for Multi-Section Soft Robots Dynamics
In spite of recent progress, soft robotics still suffers from a lack of
unified modeling framework. Nowadays, the most adopted model for the design and
control of soft robots is the piece-wise constant curvature model, with its
consolidated benefits and drawbacks. In this work, an alternative model for
multisection soft robots dynamics is presented based on a discrete Cosserat
approach, which, not only takes into account shear and torsional deformations,
essentials to cope with out-of-plane external loads, but also inherits the
geometrical and mechanical properties of the continuous Cosserat model, making
it the natural soft robotics counterpart of the traditional rigid robotics
dynamics model. The soundness of the model is demonstrated through extensive
simulation and experimental results for both plane and out-of-plane motions.Comment: 13 pages, 9 figure
Analysis and Experiments for Tendril-Type Robots
New models for the Tendril continuous backbone robot, and other similarly constructed robots, are introduced and expanded upon in this thesis. The ability of the application of geometric models to result in more precise control of the Tendril manipulator is evaluated on a Tendril prototype. We examine key issues underlying the design and operation of \u27soft\u27 robots featuring continuous body (\u27continuum\u27) elements. Inspiration from nature is used to develop new methods of operation for continuum robots. These new methods of operation are tested in experiments to evaluate their effectiveness and potential
Static kinematics for an antagonistically actuated robot based on a beam-mechanics-based model
Soft robotic structures might play a major role in
the 4th industrial revolution. Researchers have successfully
demonstrated advantages of soft robotics over traditional
robots made of rigid links and joints in several application
areas including manufacturing, healthcare and surgical
interventions. However, soft robots have limited ability to exert
higher forces when it comes to interaction with the
environment, hence, change their stiffness on demand over a
wide range. One stiffness mechanism embodies tendon-driven
and pneumatic air actuation in an antagonistic way achieving
variable stiffness values. In this paper, we apply a beammechanics-based
model to this type of soft stiffness controllable
robot. This mathematical model takes into account the various
stiffness levels of the soft robotic manipulator as well as
interaction forces with the environment at the tip of the
manipulator. The analytical model is implemented into a
robotic actuation system made of motorised linear rails with
load cells (obtaining applied forces to the tendons) and a
pressure regulator. Here, we present and analyse the
performance and limitations of our model
Design, fabrication and control of soft robots
Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.National Science Foundation (U.S.) (Grant IIS-1226883
Rate-independent soft crawlers
This paper applies the theory of rate-independent systems to model the
locomotion of bio-mimetic soft crawlers. We prove the well-posedness of the
approach and illustrate how the various strategies adopted by crawlers to
achieve locomotion, such as friction anisotropy, complex shape changes and
control on the friction coefficients, can be effectively described in terms of
stasis domains. Compared to other rate-independent systems, locomotion models
do not present any Dirichlet boundary condition, so that all rigid translations
are admissible displacements, resulting in a non-coercivity of the energy term.
We prove that existence and uniqueness of solution are guaranteed under
suitable assumptions on the dissipation potential. Such results are then
extended to the case of time-dependent dissipation
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