Intelligent Systems
Note: This research group has relocated.


2022


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Gliding lizards crashing-landing head-first into tree trunks emulated by soft robots with active tail reflexes

Siddall, R., Byrnes, G., Jusufi, A.

In Integrative and Comparative Biology, 62, pages: S288-S289, Society of Integrative and Comparative Biology, Phoenix, AZ, 2022, Society for Integrative and Comparative Biology 2022 Annual Meeting (SICB 2022) (inproceedings)

DOI [BibTex]

2022

DOI [BibTex]


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Study on the role of body and tail orientation in dynamic running Locomotion of lizards using a bioinspired robot

Chellapurath, M., Jusufi, A.

In Integrative and Comparative Biology, 62, pages: S54-S55, Society of Integrative and Comparative Biology, Phoenix, AZ, 2022, Society for Integrative and Comparative Biology 2022 Annual Meeting (SICB 2022) (inproceedings)

DOI [BibTex]

DOI [BibTex]

2021


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Cheetah tail behavior during pursuit

Patel, A., Jericevich, R., Knemeyer, A., Jusufi, A.

In Integrative and Comparative Biology, 61(Supplement 1):S5-5, Oxford University Press, Society for Integrative and Comparative Biology Annual Meeting (SICB Annual Meeting 2021), January 2021 (inproceedings)

Abstract
Rapid maneuvers are critical for animal survival in predator-prey interactions and these behaviors are more likely to apply selective pressure on performance, stability and mechanical limits compared to the extensively studied steady-state motion. Maneuvers such as jumping (eg. lemurs, mantises and jumping spiders) or aerial righting (eg. lizards or bats) often introduce instability which need to be actively compensated for. The cheetah (Acinonyx jubatus) is not only the fastest terrestrial animal but also one of the most maneuverable. These rapid maneuvers are often accompanied by dramatic swinging of its lengthy tail. However, these tail motions are under-explored. Here, we present an overview of stabilization behaviors for animals maneuvering using wings, limbs, and tails. We show kinematic simulations comparing various stabilization strategies and propose a maneuver template. We also present whole-body kinematic data obtained from captive-bred cheetahs in South Africa during 94 enrichment exercises. We analyzed over 60 tail flicks measured rotations of over 800 deg/s which further imply its use as a stabilizing element.

link (url) DOI Project Page [BibTex]

2021

link (url) DOI Project Page [BibTex]


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Tail responses facilitate lizard reorientation during directed aerial maneuverability

Siddall, R., Ibanez, V., Byrnes, G., Full, R. J., Jusufi, A.

In Integrative and Comparative Biology, 61(Supplement 1):S5-4, Oxford University Press, Society for Integrative and Comparative Biology Annual Meeting (SICB Annual Meeting 2021), January 2021 (inproceedings)

Abstract
Arboreal animals face numerous challenges when negotiating complex three dimensional terrain. Directed aerial descent and gliding flight allows for rapid traversal of arboreal environments, but presents control challenges. Some animals, such as birds or gliding squirrels, have specialized structures to modulate aerodynamic forces while airborne. However, many arboreal animals do not possess these specializations but still control posture and orientation in mid-air. One of the largest inertial segments in lizards is their tail. Inertial reorientation can be used to attain postures appropriate for controlled aerial descent. Here we discuss the role of tail inertia in a range of mid-air reorientation behaviors using experimental data from geckos in combination with general mathematic and physical models. Geckos can self-right in mid-air by tail rotation alone. Equilibrium glide behavior of geckos in a vertical wind tunnel show that they can steer towards a landing surface using rapid, circular tail rotations to control pitch and yaw. Multiple coordinated tail responses are required for the most effective terminal velocity gliding. A mathematical model allows us to explore the relationship between morphology and the capacity for inertial reorientation by conducting sensitivity analyses. Physical models further define the limits of performance and generate new control hypotheses. Such comparative analysis allows predictions about the diversity of performance across a range of lizard morphologies and provides insights into the evolution of aerial behaviors.

link (url) DOI Project Page [BibTex]

link (url) DOI Project Page [BibTex]


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Body and tail undulation measured and emulated by soft sensors provides insight on stiffness control through co-contraction

Lin, Y., Siddall, R., Banerjee, H., Schwab, F., Jusufi, A.

In Integrative and Comparative Biology, 61(Supplement 1):7-1, Oxford University Press, Society for Integrative and Comparative Biology Annual Meeting (SICB Annual Meeting 2021), January 2021 (inproceedings)

Abstract
The primary approach to measure hyper-redundant animal body structures is the use of high speed cameras in a laboratory environment, which can deprive locomotion of its proper context. Challenging conditions and complex three dimensional (e.g. rainforest or aquatic) environments make the collection of field data difficult, and prevents a complete analysis of an animal’s motion. We have developed liquid metal (eGaIn) based, hyper-elastic silicone strain sensors to measure local tail curvature with minimal impact on environment, mobility and body stiffness and therefore hope to enhance in situ biomechanics data collection without requiring manipulation of conditions. By not relying on imaging systems, long-duration data can be collected at very low latencies with minimal power and processing, and intricate movements can be measured in field experiments. This includes rapid tail surface righting, one of the first movement patterns observed in neonatal development. We propose utilizing soft sensors to measure subtle movements in aquatic animals as well as patterns of autotomized gecko tails. Ultimately, new insights into behavior, neuromuscular control and mechano-sensory receptivity can be gained. When connected to a soft undulating robotic fish with a tail beat frequency of 0.8-1.2 Hz, our sensor response is linear (R2(/sup) = 0.952) with a relative error that is well modeled by Gaussian noise (st. dev. of 0.4%). We additionally produce a data-driven model of the soft fish biorobot, which tracks experimental data to 1% mean error in displacement. We use this model to offer broader insight into the efficacy of eGaIn strain sensing to record biological movement of body caudal appendages in animals.

link (url) DOI Project Page [BibTex]

link (url) DOI Project Page [BibTex]


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Self-righting in squirrels during unexpected falls – towards the crucial function of bushy tails in arboreal mammals

Fukushima, T., Siddall, R., Byrnes, G., Nyakatura, J. A., Toussaint, S., Ardian, J.

In Integrative and Comparative Biology, 61(Supplement 1):P11-2, Oxford University Press, Society for Integrative and Comparative Biology Annual Meeting (SICB Annual Meeting 2021), January 2021 (inproceedings)

Abstract
Arboreal mammals navigate a highly three dimensional and discontinuous terrain. Tail use has been observed in many species and despite specializations, fractures from falls have been observed for example in primates. Among arboreal mammals, squirrels are widely observed to be among the most maneuverable. A recent video on YouTube went viral that showed squirrels (Sciurus carolinensis) voluntarily visiting the YouTuber's garden cross a parcour to earn a food reward. When 'failing' one of the tasks, the squirrels were catapulted off the track inducing an initially uncontrolled rotation of the body. We preliminary analyzed from the video that firstly the squirrels rotate their tails to stabilize the head to visually fix the landing site. Then, the tail starts to rotate to induce a counter moment to slow down and eventually stop the body rotation preparing the squirrel for the landing. To test the hypothesis that squirrels could utilize tails during mid-air reorientation, and gain insight into tail function essential to the mechanics of this remarkable self-righting behavior, and based on basic spatio-temporal information that we extracted from preliminary observations of Sciurus carolinensis, we use an analytical model to predict squirrel kinematics on unexpected ballistic trajectories. Righting maneuvers are optimized in a multibody model which computes tail trajectories. This model is also used to explore the limits of inertial aerial righting. To further substantiate this model and demonstrate the underlying mechanics, we developed an abstracted squirrel robot completed with an actuated tail to replicate self-righting behavior. The squirrel-inspired physical model uses two high speed brushless motors to create a 2-DoF tail capable of rapid impulsive movements to test mid-air righting in a physical model.

link (url) DOI Project Page [BibTex]

link (url) DOI Project Page [BibTex]

2020


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Modulation of Cranio-Caudal mass distribution facilitates obstacle traversal in a cursorial biorobotic model

Siddall, R. J. D., Jusufi, A.

In Integrative and Comparative Biology, 60(Supplement 1):E214-E214, Society for Integrative and Comparative Biology Annual Meeting (SICB Annual Meeting 2020), 2020 (inproceedings)

link (url) DOI [BibTex]

2020

link (url) DOI [BibTex]

2019


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Soft Sensors for Curvature Estimation under Water in a Soft Robotic Fish

Wright, Brian, Vogt, Daniel M., Wood, Robert J., Jusufi, Ardian

In 2019 2nd IEEE International Conference on Soft Robotics (RoboSoft 2019), pages: 367-371, IEEE, Piscataway, NJ, 2nd IEEE International Conference on Soft Robotics (RoboSoft 2019), 2019 (inproceedings)

DOI Project Page [BibTex]

2019

DOI Project Page [BibTex]


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Co-Contraction facilitates Body Stiffness Modulation during Swimming with Sensory Feedback in a Soft Biorobotic Physical Model

Jusufi, A., Vogt, D., Wood, R. J.

In Integrative and Comparative Biology, 59(Supplement 1):E116-E116, Society for Integrative and Comparative Biology Annual Meeting (SICB Annual Meeting 2019), 2019 (inproceedings)

link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Heads or Tails? Cranio-Caudal Mass Distribution for Robust Locomotion with Biorobotic Appendages Composed of 3D-Printed Soft Materials

Siddall, R., Schwab, F., Michel, J., Weaver, J., Jusufi, A.

In Biomimetic and Biohybrid Systems, 11556, pages: 240-253, Lecture Notes in Artificial Intelligence, (Editors: Martinez-Hernandez, Uriel and Vouloutsi, Vasiliki and Mura, Anna and Mangan, Michael and Asada, Minoru and Prescott, Tony J. and Verschure, Paul F. M. J.), Springer, Cham, Living Machines 2019: 8th International Conference on Biomimetic and Biohybrid Systems, 2019 (inproceedings)

DOI [BibTex]

DOI [BibTex]