327 research outputs found
Development of a framework to link functional activity and circuit wiring diagrams in the zebrafish larva brain
No full textIn recent years, there has been a significant increase in the developing of techniques to study the brain, both in terms of the function and of the connectivity organization. Whole brain dense anatomical reconstruction at synaptic resolution have provided insight into the brain architecture and how the information is transmitted. However, these reconstructions, even when the synaptic input/output relationship are known, are still far from revealing the general connectivity patterns of the neuronal circuits across the brain and their functional organization in networks. On the other hand, light based techniques allow the functional characterization of the neuronal activity associated with resting state activity or sensory-driven dynamics. Here, we present two methods to analyze the circuit mechanisms on the zebrafish larvae, a small vertebrate with a completely optical accessible brain. First, a tool for identifying functionally relevant networks based on their structural connectivity patterns which is adaptable to different anatomical datasets with or without identified synapses. Second, an alternative optical layout for high resolution whole-brain imaging which can be used to reconstruct the brain dynamics during sensory stimulation. The combination of these two tools can provide a deeper understanding on how the structure of the nervous system supports the flow of information and offer a more accurate basis for the formulation of models of the circuit working principles.In recent years, there has been a significant increase in the developing of techniques to study the brain, both in terms of the function and of the connectivity organization. Whole brain dense anatomical reconstruction at synaptic resolution have provided insight into the brain architecture and how the information is transmitted. However, these reconstructions, even when the synaptic input/output relationship are known, are still far from revealing the general connectivity patterns of the neuronal circuits across the brain and their functional organization in networks. On the other hand, light based techniques allow the functional characterization of the neuronal activity associated with resting state activity or sensory-driven dynamics. Here, we present two methods to analyze the circuit mechanisms on the zebrafish larvae, a small vertebrate with a completely optical accessible brain. First, a tool for identifying functionally relevant networks based on their structural connectivity patterns which is adaptable to different anatomical datasets with or without identified synapses. Second, an alternative optical layout for high resolution whole-brain imaging which can be used to reconstruct the brain dynamics during sensory stimulation. The combination of these two tools can provide a deeper understanding on how the structure of the nervous system supports the flow of information and offer a more accurate basis for the formulation of models of the circuit working principles
Manipolatore robotico cartesiano a giunti flessibili per la automazione di operazioni su parti di piccole dimensioni
No full textResearch activities of the Applied Mechanics group of the University of Genova
No full textWithin the Italian academic system, the sector of Applied Mechanics (“Meccanica Applicata alle Macchine”) represents one of the engineering disciplines with the most significant historical background. It encompasses scientific, technological, and educational aspects related to the mechanics of machines, both from the perspective of their components and their operation as complex systems. The methodological approaches employed are varied: theoretical, numerical, and
experimental. Regarding the educational aspects, the sector of Applied Mechanics is fundamental (characterizing) for Bachelor’s Degrees in Mechanical Engineering (L-9 class) and for Master’s Degrees in Mechanical Engineering (LM-33 class) and Automation Engineering (LM-25 class). Additionally, it is essential for the PhD Degree in Mechanical, Energy, and Management Engineering at the DIME Department of the University of Genova. The professors of the Applied Mechanics group at the University of Genova are actively engaged in research projects funded at the regional, national, European, and industrial levels. Collaborations are ongoing with Stellantis, Ansaldo Energia, Fincantieri, Leonardo, Hitachi, among others. In this context, the Applied Mechanics sector advances both innovative theoretical contributions and experimental studies aimed at practical applications and technology transfer. The research topics are highly interdisciplinary and include: - modelling, design, prototyping, and control of innovative industrial robotic systems (two robotic
lines developed in collaboration with Stellantis are currently operational in final car assembly); - modelling, design, and prototyping of service robots for inspection, agriculture, and demining; - modelling and analysis of micromechanical systems, including compliant mechanisms optimized
through analytical and numerical approaches; - dynamic analysis of systems characterized by vibrations, variable contacts and impacts (e.g., gear trains); - numerical analysis techniques for mechanical and aeromechanical systems; - definition and application of methodologies for dynamical analysis, model identification, diagnostics, and monitoring of structural integrity (a monitoring system for turbomachinery rotor blades, developed in collaboration with Ansaldo Energia, is currently in use in several plants)
Simulation of crisis affecting critical infrastructures and industrial plants
No full textThis paper proposes a model for reproducing human behaviors and it is devoted to evaluate the operation performance in case of crisis with special attention to cases involving multiple actors such as fire-fighters, police, ambulances, civil protection and national reserve. The paper present the general scheme and the data structure used to conduct experiments related to cases of flooding and hazardous material spills in industrial and urban areas
Dynamic model and performance assessment of the natural motion of a SCARA-like manipulator in pick-and-place tasks
No full textThe energy efficiency of manipulators performing cyclic motions can be enhanced by utilizing the so-called natural motion, namely, the natural oscillations that occur when elastic elements are placed in series or parallel with the actuators. In this paper, the natural motion of the RR-4R-R robot is discussed. This manipulator exhibits a 4-DOF mobility similar to that of the widespread SCARA robot, but the vertical prismatic joint is replaced by a four-bar mechanism. This modification, along with the adoption of a direct-drive actuator for the four-bar mechanism, makes it easier to achieve the elastic balancing of the robot, allowing the exploitation of its natural motion. The robot dynamics is analysed using the Lagrangian approach. Two types of elastic balancing are considered: one using a torsional spring and one using a linear coil spring. A simplified model of the vertical motion is then proposed, decoupled from the inertial effects of the horizontal motion, and used to estimate the vertical natural period. The behaviour of the manipulator with natural elastic balancing is compared with that obtained with exact elastic balancing, which provides an indifferent equilibrium in any robot position. This comparison is first carried out in the time domain, and then the space of the robot operating conditions is sampled through multibody simulations, performed to investigate the threshold of convenience between exact and natural balancing. Simulation results indicate that exploiting the natural motion of the RR-4R-R manipulator can significantly reduce energy consumption in a wide range of industrial applications involving pick-and-place tasks
HYPERBARIC PLANT SIMULATION FOR INDUSTRIAL APPLICATIONS
No full textSeveral industrials sectors require to extend underwater capabilities by adopting alternative and multiple solutions both involving human divers as well as robotic technologies such as ROVs & AUVs. In general the main mandate is to improve performance reducing costs and risks. On the other side, new technologies and advancements are enabling to further develop the potential of the above mentioned solutions; for instance the authors propose a new generation of computer based Hyperbaric Plant Simulators that are pretty promising for improving training & education without rising costs of underwater man based operations. This paper proposes an innovative approach in M&S for the Hyperbaric Life Support Supervisors (LSS) as well as other operators active into diving activities
Position analysis of a class of translational parallel mechanisms
No full textThe formulation of the forward position analysis of parallel kinematics mechanisms (PMs) is in most cases very complex. The authors propose a general explicit solution to the problem for a wide class of 3-DOF translational architectures, the tetrahedral mechanisms. The class gathers pure translational parallel mechanisms satisfying three hypotheses on geometry and mobility. No assumption is made about symmetry; the actuation can be redundant or nonredundant. Explanatory examples are discussed
Innate visual discrimination abilities of zebrafish larvae
No full textThe ability to discriminate between objects visually plays a key role in animals’ interactions with their environment because it enables them to recognise companions, prey, and predators. In the zebrafish, Danio rerio, hatching occurs early on during development (48–72 h post fertilisation), and the larvae must forage and evade predators despite their immature sensory and cognitive systems. Using a preference paradigm, we investigated whether larval zebrafish are nonetheless capable of discriminating between visual stimuli. We found that larvae discriminated not only between figures with different colours or different shapes, but also between two identical figures with different orientations and between sets of figures with different numerosities. By manipulating larvae’s exposure to objects before the test, we demonstrated that their discrimination abilities are innate and do not depend upon experience. This study highlighted that zebrafish possess relatively sophisticated visual discrimination abilities even at the larval stage. These abilities likely improve larval survival via the recognition of biologically relevant stimuli
Mechanical modelling and control layout of a Mini-PKM for assembly applications
No full textThe paper deals with a parallel robot for miniaturized assembly applications. The machine is based on the cartesian-parallel scheme and it is equipped with flexure revolute joints, in order to avoid stick-slip phenomena and reach high positioning accuracy (better than I mu m).
Its workspace volume is a cube of side 30 mm. The three flexible robot arms have internal non-actuated degrees of freedom, which can be passively damped or, if needed, actively controlled; the vibrational behaviour of the arms has been analyzed by means of a Pseudo-Rigid Body model, and the results suggests the adoption of passive damping.
The actuation is based on linear cog-free motors; the actuation and control layout of the prototype is discussed
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