74 research outputs found

    Fast Sensing and Adaptive Actuation for Robust Legged Locomotion

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    Robust legged locomotion in complex terrain demands fast perturbation detection and reaction. In animals, due to the neural transmission delays, the high-level control loop involving the brain is absent from mitigating the initial disturbance. Instead, the low-level compliant behavior embedded in mechanics and the mid-level controllers in the spinal cord are believed to provide quick response during fast locomotion. Still, it remains unclear how these low- and mid-level components facilitate robust locomotion. This thesis aims to identify and characterize the underlining elements responsible for fast sensing and actuation. To test individual elements and their interplay, several robotic systems were implemented. The implementations include active and passive mechanisms as a combination of elasticities and dampers in multi-segment robot legs, central pattern generators inspired by intraspinal controllers, and a synthetic robotic version of an intraspinal sensor. The first contribution establishes the notion of effective damping. Effective damping is defined as the total energy dissipation during one step, which allows quantifying how much ground perturbation is mitigated. Using this framework, the optimal damper is identified as viscous and tunable. This study paves the way for integrating effective dampers to legged designs for robust locomotion. The second contribution introduces a novel series elastic actuation system. The proposed system tackles the issue of power transmission over multiple joints, while featuring intrinsic series elasticity. The design is tested on a hopper with two more elastic elements, demonstrating energy recuperation and enhanced dynamic performance. The third contribution proposes a novel tunable damper and reveals its influence on legged hopping. A bio-inspired slack tendon mechanism is implemented in parallel with a spring. The tunable damping is rigorously quantified on a central-pattern-generator-driven hopping robot, which reveals the trade-off between locomotion robustness and efficiency. The last contribution explores the intraspinal sensing hypothesis of birds. We speculate that the observed intraspinal structure functions as an accelerometer. This accelerometer could provide fast state feedback directly to the adjacent central pattern generator circuits, contributing to birds’ running robustness. A biophysical simulation framework is established, which provides new perspectives on the sensing mechanics of the system, including the influence of morphologies and material properties. Giving an overview of the hierarchical control architecture, this thesis investigates the fast sensing and actuation mechanisms in several control layers, including the low-level mechanical response and the mid-level intraspinal controllers. The contributions of this work provide new insight into animal loco-motion robustness and lays the foundation for future legged robot design

    2023- The Twenty-seventh Annual Symposium of Student Scholars

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    The full program book from the Twenty-seventh Annual Symposium of Student Scholars, held on April 18-21, 2023. Includes abstracts from the presentations and posters.https://digitalcommons.kennesaw.edu/sssprograms/1027/thumbnail.jp

    Non-inertial Undulatory Locomotion Across Scales

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    Locomotion is crucial to behaviors such as predator avoidance, foraging, and mating. In particular, undulatory locomotion is one of the most common forms of locomotion. From microscopic flagellates to swimming fish and slithering snakes, this form of locomotion is a remarkably robust self-propulsion strategy that allows a diversity of organisms to navigate myriad environments. While often thought of as exclusive to limbless organisms, a variety of locomotors possessing few to many appendages rely on waves of undulation for locomotion. In inertial regimes, organisms can leverage the forces generated by their body and the surrounding medium's inertia to enhance their locomotion (e.g., coast or glide). On the other hand, in non-inertial regimes self-propulsion is dominated by damping (viscous or frictional), and thus the ability for organisms to generate motion is dependent on the sequence of internal shape changes. In this thesis, we study a variety of undulating systems that locomote in highly damped regimes. We perform studies on systems ranging from zero to many appendages. Specifically, we focus on four distinct undulatory systems: 1) C. elegans, 2) quadriflagellate algae (bearing four flagella), 3) centipedes on terrestrial environments, and 4) centipedes on fluid environments. For each of these systems, we study how the coordination of their many degrees of freedom leads to specific locomotive behaviors. Further, we propose hypotheses for the observed behaviors in the context of each of these system's ecology.Ph.D

    Design and control of a novel bionic mantis shrimp robot

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    This article presents the development of a novel bionic robot, which is inspired by agile and fast mantis shrimp in the ocean. The developed bionic mantis shrimp robot has ten rigid-flexible swimming feet (pleopods) for swimming propulsion and a rope-driven spine for its body bending. By studying the motion trajectory of biological mantis shrimp, the kinematic gait planning of the bionic pleopod is completed and the central pattern generator controller of the bionic mantis shrimp robot applicable to the coupled motion of multiple pleopods is proposed. The controller is experimentally verified to effectively simulate the swimming motion of mantis shrimp, which enables the robot to reach a maximum swimming velocity of 0.28 m/s (0.46 body length per second) and a minimum turning radius of 0.36 m.The influence of control parameters on the robot's swimming performance is then investigated. Experiments are conducted to show that the oscillation frequency of the bionic pleopod plays a major positive role in the robot's swimming speed. This article has demonstrated the effectiveness of the proposed mechanism design and motion control method for a bionic mantis shrimp robot and laid the foundation for the further exploration of bionic mantis shrimp robots in rugged seabed environments

    Neuromorphic Computing for Interactive Robotics: A Systematic Review

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    Modelling functionalities of the brain in human-robot interaction contexts requires a real-time understanding of how each part of a robot (motors, sensors, emotions, etc.) works and how they interact all together to accomplish complex behavioural tasks while interacting with the environment. Human brains are very efficient as they process the information using event-based impulses also known as spikes, which make living creatures very efficient and able to outperform current mainstream robotic systems in almost every task that requires real-time interaction. In recent years, combined efforts by neuroscientists, biologists, computer scientists and engineers make it possible to design biologically realistic hardware and models that can endow the robots with the required human-like processing capability based on neuromorphic computing and Spiking Neural Network (SNN). However, while some attempts have been made, a comprehensive combination of neuromorphic computing and robotics is still missing. In this article, we present a systematic review of neuromorphic computing applications for socially interactive robotics.We first introduce the basic principles, models and architectures of neuromorphic computation. The remaining articles are classified according to the applications they focus on. Finally, we identify the potential research topics for fully integrated socially interactive neuromorphic robots

    Using reconstructed visual reality in ant navigation research

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    Insects have low resolution eyes and a tiny brain, yet they continuously solve very complex navigational problems; an ability that underpins fundamental biological processes such as pollination and parental care. Understanding the methods they employ would have profound impact on the fields of machine vision and robotics. As our knowledge on insect navigation grows, our physical, physiological and neural models get more complex and detailed. To test these models we need to perform increasingly sophisticated experiments. Evolution has optimised the animals to operate in their natural environment. To probe the fine details of the methods they utilise we need to use natural visual scenery which, for experimental purposes, we must be able to manipulate arbitrarily. Performing physiological experiments on insects outside the laboratory is not practical and our ability to modify the natural scenery for outdoor behavioural experiments is very limited. The solution is reconstructed visual reality, a projector that can present the visual aspect of the natural environment to the animal with high fidelity, taking the peculiarities of insect vision into account. While projectors have been used in insect research before, during my candidature I designed and built a projector specifically tuned to insect vision. To allow the ant to experience a full panoramic view, the projector completely surrounds her. The device (Antarium) is a polyhedral approximation of a sphere. It contains 20 thousand pixels made out of light emitting diodes (LEDs) that match the spectral sensitivity of Myrmecia. Insects have a much higher fusion frequency limit than humans, therefore the device has a very high flicker frequency (9kHz) and also a high frame rate (190fps). In the Antarium the animal is placed in the centre of the projector on a trackball. To test the trackball and to collect reference data, outdoor experiments were performed where ants were captured, tethered and placed on the trackball. The apparatus with the ant on it was then placed at certain locations relative to the nest and the foraging tree and the movements of the animal on the ball were recorded and analysed. The outdoor experiments proved that the trackball was well suited for our ants, and also provided the baseline behaviour reference for the subsequent Antarium experiments. To assess the Antarium, the natural habitat of the experimental animals was recreated as a 3-dimensional model. That model was then projected for the ants and their movements on the trackball was recorded, just like in the outdoor experiments Initial feasibility tests were performed by projecting a static image, which matches what the animals experienced during the outdoor experiments. To assess whether the ant was orienting herself relative to the scene we rotated the projected scene around her and her response monitored. Statistical methods were used to compare the outdoor and in-Antarium behaviour. The results proved that the concept was solid, but they also uncovered several shortcomings of the Antarium. Nevertheless, even with its limitations the Antarium was used to perform experiments that would be very hard to do in a real environment. In one experiment the foraging tree was repositioned in or deleted from the scene to see whether the animals go to where the tree is or where by their knowledge it should be. The results suggest the latter but the absence or altered location of the foraging tree certainly had a significant effect on the animals. In another experiment the scene, including the sky, were re-coloured to see whether colour plays a significant role in navigation. Results indicate that even very small amount of UV information statistically significantly improves the navigation of the animals. To rectify the device limitations discovered during the experiments a new, improved projector was designed and is currently being built

    Towards understanding of climbing, tip-over prevention and self-righting behaviors in Hexapoda

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    Die vorliegende Dissertation mit dem Titel “Towards understanding of climbing, tip-over prevention and self-righting behaviors in Hexapoda” untersucht in drei Studien exemplarisch, wie (i) Wüstenameisen ihre Beine einsetzen um An- und Abstiege zu überwinden, wie (ii) Wüsten- und Waldameisen ein Umkippen an steilen Anstiegen vermeiden, und wie sich (iii) Madagaskar-Fauchschaben, Amerikanische Großschaben und Blaberus discoidalis Audinet-Servill, 1839 aus Rückenlagen drehen und aufrichten. Neuartige biomechanischen Beschreibungen umfassen unter anderem: Impuls- und Kraftwirkungen einzelner Ameisenbeine auf den Untergrund beim Bergauf- und Bergabklettern, Kippmomente bei kletternden Ameisen, Energiegebirge-Modelle (energy landscapes) zur Quantifizierung der Körperform für die funktionelle Beschreibung des Umdrehens aus der Rückenlage

    Selected Papers from IEEE ICASI 2019

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    The 5th IEEE International Conference on Applied System Innovation 2019 (IEEE ICASI 2019, https://2019.icasi-conf.net/), which was held in Fukuoka, Japan, on 11–15 April, 2019, provided a unified communication platform for a wide range of topics. This Special Issue entitled “Selected Papers from IEEE ICASI 2019” collected nine excellent papers presented on the applied sciences topic during the conference. Mechanical engineering and design innovations are academic and practical engineering fields that involve systematic technological materialization through scientific principles and engineering designs. Technological innovation by mechanical engineering includes information technology (IT)-based intelligent mechanical systems, mechanics and design innovations, and applied materials in nanoscience and nanotechnology. These new technologies that implant intelligence in machine systems represent an interdisciplinary area that combines conventional mechanical technology and new IT. The main goal of this Special Issue is to provide new scientific knowledge relevant to IT-based intelligent mechanical systems, mechanics and design innovations, and applied materials in nanoscience and nanotechnology
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