Biology subjects

Jusufi, A.

Publications and source records attributed to Jusufi, A..

3 recordsLinked to original sources

bioRxiv2024

Asymmetric Fin Shape changes Swimming Dynamics of Ancient Marine Reptiles' Soft Robophysical Models

Animals have evolved highly effective locomotion capabilities in terrestrial, aerial, and aquatic environments. Over lifes history, mass extinctions have wiped out unique animal species with specialized adaptations, leaving paleontologists to reconstruct their locomotion through fossil analysis. Despite advancements, little is known about how extinct megafauna, such as the Ichthyosauria one of the most successful lineages of marine reptiles, utilized their varied morphologies for swimming. Traditional robotics struggle to mimic extinct locomotion effectively, but the emerging soft robotics field offers a promising alternative to overcome this challenge. This paper aims to bridge this gap by studying Mixosaurus locomotion with soft robotics, combining material modeling and biomechanics in physical experimental validation. Combining a soft body with soft pneumatic actuators, the soft robotic platform described in this study investigates the correlation between asymmetrical fins and buoyancy by recreating the pitch torque generated by extinct swimming animals. We performed a comparative analysis of thrust and torque generated by Carthorhyncus, Utatsusaurus, Mixosaurus, Guizhouichthyosaurus, and Ophthalmosaurus tail fins in a flow tank. Experimental results suggest that the pitch torque on the torso generated by hypocercal fin shapes such as found in model systems of Guizhouichthyosaurus, Mixosaurus and Utatsusaurus produce distinct ventral body pitch effects able to mitigate the animals non-neutral buoyancy. This body pitch control effect is particularly pronounced in Guizhouichthyosaurus, which results suggest would have been able to generate high ventral pitch torque on the torso to compensate for its positive buoyancy. By contrast, homocercal fin shapes may not have been conducive for such buoyancy compensation, leaving torso pitch control to pectoral fins, for example. Across the range of the actuation frequencies of the caudal fins tested, resulted in oscillatory modes arising, which in turn can affect the for-aft thrust generated.

biophysics↗

bioRxiv2024

Repetitive Learning Control for Body Caudal Undulation with Soft Sensory Feedback

Soft bio-inspired robotics is a growing field of research that seeks to close the gap with animal robustness and adaptability where conventional robots fall short. The embedding of sensors with the capability to discriminate between different body deformation modes is a key technological challenge in soft robotics to enhance robot control - a difficult task for such kinds of systems with high degrees of freedom. The recently conceived Linear Repetitive Learning Estimation Scheme (LRLES) - to be included in the traditional Proportional Integral Derivative (PID) control - is proposed here as a way to compensate for uncertain dynamics on a soft swimming robot, which is actuated with soft pneumatic actuators and equipped with soft sensors providing proprioceptive information pertaining to lateral body caudal bending akin to a goniometer. The proposed controller is derived in detail and experimentally validated, with the experiment consisting of tracking a desired trajectory for bending angle while continuously oscillating with a constant frequency. The results are compared vis a vis those achieved with the traditional PID controller, finding that the PID endowed with the LRLES outperforms the PID controller (though the latter has been separately tuned) and experimentally validating the novel controllers effectiveness, accuracy, and matching speed.

bioinformatics↗

bioRxiv2022

Tail wags the dog is unsupported by biomechanical Modeling of Canidae Tails Use during Terrestrial Motion

Dogs and other members of Canidae utilize their tails for different purposes, including agile movements, such as running and jumping. In this study, we utilized motion capture biomechanical data of a border collie executing an agile rotational jump maneuver. This data created a 17-segment biomechanical model of the border collies (Canis familiaris) limb movement during agile jumps. This model was verified by comparing it to the biomechanical movement and fitting the dogs agile task with an RMSE less than 2.5%. Using this joint model, we held specific segments constant to view their inertial impact on the dog during the aerial phase of jumping. Results suggest that the tail, hind limbs, and fore limb provides little to no inertial advantage during these rotational jump maneuvers. The tail of dogs likely does have a minimal impact on inertia, the opposite of animals like the gecko. This work could alleviate unknown biomechanical use of the tails to understand the behavioral biomechanics of lesser-known species in their ability to use their tail for rapid and taxing behaviors, including sprinting or climbing.

biophysics↗