Abstract Conventional approaches in prescribing controls for locomoting robots assume control over all input degrees of freedom (DOFs). Many robots, such as those with non-holonomic constraints, may not require or even allow for direct command over all DOFs. In particular, a snake robot with more than three links with non-holonomic constraints cannot achieve arbitrary configurations in all of its joints while simultaneously locomoting. For such a system, we assume partial command over a subset of the joints, and allow the rest to evolve according to kinematic chained and dynamic models. Different combinations of actuated and passive joints, as well as joints with dynamic elements such as torsional springs, can drastically change the coupling interactions and stable oscillations of joints. We use tools from nonlinear analysis to understand emergent oscillation modes of various robot configurations and connect them to overall locomotion using geometric mechanics and feedback control for robots that may not fully utilize all available inputs. We also experimentally verify observations and motion planning results on a physical non-holonomic snake robot
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Dynamics of a circular cylinder with a passive degree of freedom interacting with an inviscid fluid containing a point vortex
In the recent past the design of many aquatic robots has been inspired by the motion of fish. Actuated internal rotors or moving masses have been frequently used either for propulsion and or the control of such robots. However the effect of internal passive degrees of freedom or passive appendages on the motion of such robots is poorly understood. In this paper we present a minimal model that demonstrates the influence of passive degrees of freedom on an aquatic robot. The model is of a circular cylinder with a passive internal rotor, immersed in an inviscid fluid interacting with point vortices. We show through numerics that the motion of the cylinder containing a passive degree of freedom is significantly different than one without. These results show that the mechanical feedback via passive degrees of freedom could be a useful way to control the motion of aquatic robots.
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- Award ID(s):
- 1563315
- PAR ID:
- 10026102
- Date Published:
- Journal Name:
- ASME Dynamic Systems and Control Conference
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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