Active visual tracking of free-swimming robotic fish based on automatic recognition

Author(s):  
Feihu Sun ◽  
Junzhi Yu ◽  
Shifeng Chen ◽  
De Xu
Author(s):  
Paul Phamduy ◽  
Jayhwan Cheong ◽  
Maurizio Porfiri

The operation of autonomous underwater vehicles is often hindered by their battery capacity, limiting the duration of its use. Here, we propose an integrated solution for autonomous charging of a robotic fish via direct contact through a novel claw mechanism for docking guidance. To assist the robotic fish in the docking process, the system incorporates a charging station designed with form-fit claws. A controller is designed to monitor the battery level of the robotic fish during free swimming and coordinate the docking process with respect to the maneuvers of both the robot and form-fit claws. Upon recognizing a low battery level, the controller commands the robotic fish to begin the docking process, and video feedback from an overhead camera is used to inform the autonomous navigation toward the charging station. After reaching a battery level threshold, the robotic fish is then released back in the water and returns to free swimming until the battery is discharged again. Through a series of experiments, we demonstrate the possibility of prolonged operation, consisting of repeated cycles of autonomous charging. Our proposed charging method enables prolonged autonomous swimming with minimal human supervision, opening the door for new, transformative applications of robotic fish in laboratory research and field deployment.


PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e76123 ◽  
Author(s):  
Sachit Butail ◽  
Tiziana Bartolini ◽  
Maurizio Porfiri

Author(s):  
Jianxun Wang ◽  
Philip K. McKinley ◽  
Xiaobo Tan

In this paper, we develop a new dynamic model for a robotic fish propelled by a flexible tail actuated at the base. The tail is modeled by multiple rigid segments connected in series through rotational springs and dampers, and the hydrodynamic force on each segment is evaluated using Lighthill's large-amplitude elongated-body theory. For comparison, we also construct a model using linear beam theory to capture the beam dynamics. To assess the accuracy of the models, we conducted experiments with a free-swimming robotic fish. The results show that the two models have almost identical predictions when the tail undergoes small deformation, but only the proposed multisegment model matches the experimental measurement closely for all tail motions, demonstrating its promise in the optimization and control of tail-actuated robotic fish.


Author(s):  
Paul Phamduy ◽  
Miguel Angel Vazquez ◽  
Changsu Kim ◽  
Violet Mwaffo ◽  
Alessandro Rizzo ◽  
...  

10.5772/62887 ◽  
2016 ◽  
Vol 13 (2) ◽  
pp. 62 ◽  
Author(s):  
Junzhi Yu ◽  
Shifeng Chen ◽  
Zhengxing Wu ◽  
Weibing Wang

Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.


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