A flexible, reaction-wheel-driven fish robot: Flow sensing and flow-relative control

2016 ◽  
Author(s):  
Feitian Zhang ◽  
Patrick Washington ◽  
Derek A. Paley
Keyword(s):  
Reaction Wheel ◽  
Fish Robot ◽  
Flow Sensing

Distributed Flow Sensing Using Bayesian Estimation for a Flexible Fish Robot

2015 ◽  
Author(s):  
Feitian Zhang ◽  
Francis D. Lagor ◽  
Derrick Yeo ◽  
Patrick Washington ◽  
Derek A. Paley
Keyword(s):  
Flow Model ◽  
Pressure Sensors ◽  
Estimation Algorithm ◽  
Flow Speed ◽  
The Body ◽  
Fish Robot ◽  
Flow Estimation ◽  
Flow Sensing ◽  
Time Flow ◽  
Recursive Bayesian Filter

Flexibility plays an important role in fish behaviors by enabling high maneuverability for predator avoidance and swimming in turbulence. In this paper, we present a novel, flexible fish robot equipped with distributed pressure sensors for flow sensing. The body of the robot is made of a soft, hyperelastic material that provides flexibility. The fish robot features a Joukowski-foil shape conducive to modeling the fluid analytically. A quasisteady potential-flow model is adopted for real-time flow estimation, whereas a discrete-time vortex-shedding flow model is used for higher-fidelity simulation. The dynamics for the flexible fish robot are presented, and a reduced model for one-dimensional swimming is derived. A recursive Bayesian filter assimilates pressure measurements for estimating the flow speed, angle of attack, and foil camber. Simulation and experimental results are presented to show the effectiveness of the flow estimation algorithm.

Distributed flow sensing for closed-loop speed control of a flexible fish robot

2015 ◽  
Vol 10 (6) ◽  
pp. 065001 ◽  
Author(s):  
Feitian Zhang ◽  
Francis D Lagor ◽  
Derrick Yeo ◽  
Patrick Washington ◽  
Derek A Paley
Keyword(s):  
Closed Loop ◽  
Speed Control ◽  
Fish Robot ◽  
Flow Sensing

scholarly journals Electric signal synchronization as a behavioural strategy to generate social attention in small groups of mormyrid weakly electric fish and a mobile fish robot

2021 ◽  
Author(s):  
Martin Worm ◽  
Tim Landgraf ◽  
Gerhard von der Emde
Keyword(s):  
Small Groups ◽  
Electric Fish ◽  
Social Attention ◽  
Weakly Electric Fish ◽  
Electric Signal ◽  
Fish Robot ◽  
Wide Range ◽  
Signal Synchronization ◽  
Weakly Electric ◽  
Attention Hypothesis

AbstractAfrican weakly electric fish communicate at night by constantly emitting and perceiving brief electrical signals (electric organ discharges, EOD) at variable inter-discharge intervals (IDI). While the waveform of single EODs contains information about the sender’s identity, the variable IDI patterns convey information about its current motivational and behavioural state. Pairs of fish can synchronize their EODs to each other via echo responses, and we have previously formulated a ‘social attention hypothesis’ stating that fish use echo responses to address specific individuals and establish brief dyadic communication frameworks within a group. Here, we employed a mobile fish robot to investigate the behaviour of small groups of up to four Mormyrus rume and characterized the social situations during which synchronizations occurred. An EOD-emitting robot reliably evoked social following behaviour, which was strongest in smaller groups and declined with increasing group size. We did not find significant differences in motor behaviour of M. rume with either an interactive playback (echo response) or a random control playback by the robot. Still, the robot reliably elicited mutual synchronizations with other fish. Synchronizations mostly occurred during relatively close social interactions, usually when the fish that initiated synchronization approached either the robot or another fish from a distance. The results support our social attention hypothesis and suggest that electric signal synchronization might facilitate the exchange of social information during a wide range of social behaviours from aggressive territorial displays to shoaling and even cooperative hunting in some mormyrids.

Reaction wheel attitude control for space vehicles

1959 ◽  
Vol 4 (3) ◽  
pp. 139-149 ◽  
Author(s):  
R. Froelich ◽  
H. Papapoff
Keyword(s):  
Attitude Control ◽  
Space Vehicles ◽  
Reaction Wheel
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