The seismic events occurred in recent years have highlighted the extreme vulnerability of a large part of existing Italian highway infrastructure. The principal skeleton of Italian highway network was built during the...
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The seismic events occurred in recent years have highlighted the extreme vulnerability of a large part of existing Italian highway infrastructure. The principal skeleton of Italian highway network was built during the mid-century, where the knowledge of seismic engineering was still limited. Also, the old age of structures with the need of seismic assessment, is forcing highway stakeholders to give an answer to a strategic query: should thousands of highway bridges be destroyed and re-built with in force regulations, or do they just need a retrofit? The objective of this work is to reply concretely to that issue, investigating the combined use of a dissipative smart-passive control strategy and an innovative isolation system to protect seismically excited structures. It is based on the use of seismic early warning information (SEWI) to optimally calibrate variable dampers for a higher reduction of the structural response. In particular, the adoption of dissipative magnetorheological (MR) dampers calibrated according to the forecasted value of the seismic peak ground acceleration, and a new adaptive control algorithm, are herein proposed. Moreover, to reduce the influence of support devices in the global viaduct behavior, a prototype of double concave friction pendulum (DCFP), with a very low value of friction coefficient, is implemented. The effectiveness and robustness of the DCFPs system with smart-passive MR dampers driven by the SEWI, are demonstrated with reference to an existing Italian highway viaduct for the first time. The results of non-linear time history analysis using seismic registrations of natural events are then compared with a consolidate passive technique characterized by lead rubber bearings (LRB), applied to the same structure. The control technique results were promising for the ease of implementation for structures, effectiveness, even compared with a widespread passive system and robustness, given an estimate of the incoming earthquake by a s
Multi-wheel vehicles are extensively utilized in civil and military fields,since they are powerful in complex environment,originating from over-actuated multi-wheel driven *** is necessary that the kinematics and dyna...
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Multi-wheel vehicles are extensively utilized in civil and military fields,since they are powerful in complex environment,originating from over-actuated multi-wheel driven *** is necessary that the kinematics and dynamics of all wheels have to be coordinated *** this paper,the optimized torque allocation strategy on skid steering multi-wheel vehicle driven by independent in-wheel motors has been proposed based on vehicle dynamical model and wheel torque distribution ***,weighting control allocation error and control energy as the optimization target,wheel torque control allocation was solved using quadratic programming *** with wheel slip control and actuator fault redundancy control schemes,the optimization algorithm is correspondingly implemented,which improved the dynamic performance and safety of steering *** effectiveness of wheel torque distribution strategy was validated in Matlab/Simulink which demonstrated that torque can be redistributed among the effective motors when one wheel motor fails.
The Caenorhabditis elegans (C. elegans) worm is a well-studied biological organism model. The nervous system of C. elegans is particularly appealing to study, since it is a tractable fully functional neuronal network ...
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The Caenorhabditis elegans (C. elegans) worm is a well-studied biological organism model. The nervous system of C. elegans is particularly appealing to study, since it is a tractable fully functional neuronal network for which electro-physical connectivity map (connectome) is fully resolved [1,2]. In this work, we use a recently established computational dynamical model of the C. elegans nervous system, which incorporated the static connectome data with intrinsic properties of neurons and their interactions. With this model, it has been demonstrated that robust oscillatory movements in motor neurons along the body can be invoked by constant current excitation of command sensory neurons (e.g., PLM neurons associated with forward crawling), and that their activation corresponds to low-dimensional Hopf bifurcation [3]. While these first results validated the model, it is exciting to learn and visualize how the nervous system transforms its oscillatory dynamics to the muscles to support robust full body movements (e.g., forward crawling) [4]. Moreover, it is intriguing to understand the optimal sensory stimulations that cause these movements to persist. We explore these questions by developing methods to visualize network activity in a physical space and creating a model for C. elegans musculature as a viscoelastic rod with discrete rigid segments [5]. We map the neuronal dynamics such that they activate the muscles and deform the rod. When motor neuron activity stimulates muscles [2], this activation is translated into force applied to the rod, which moves in accordance with the physical properties of C. elegans. By stimulating the command PLM neurons, we establish for the first time that motor neuron dynamics are indeed producing coherent oscillatory full body movements that resemble forward crawling. We utilize our computational full body model to determine the appropriate sensory input for behavior, such as crawling, to persist after explicit external stimulation (
The artificial pancreas (closed-loop system) addresses the unmet clinical need for improved glucose control whilst reducing the burden of diabetes self-care in type 1 diabetes. Glucose-responsive insulin delivery abov...
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The artificial pancreas (closed-loop system) addresses the unmet clinical need for improved glucose control whilst reducing the burden of diabetes self-care in type 1 diabetes. Glucose-responsive insulin delivery above and below a preset insulin amount informed by sensor glucose readings differentiates closed-loop systems from conventional, threshold-suspend and predictive-suspend insulin pump therapy. Insulin requirements in type 1 diabetes can vary between one-third-threefold on a daily basis. Closed-loop systems accommodate these variations and mitigate the risk of hypoglycaemia associated with tight glucose control. In this review we focus on the progress being made in the development and evaluation of closed-loop systems in outpatient settings. Randomised transitional studies have shown feasibility and efficacy of closed-loop systems under supervision or remote monitoring. Closed-loop application during free-living, unsupervised conditions by children, adolescents and adults compared with sensor-augmented pumps have shown improved glucose outcomes, reduced hypoglycaemia and positive user acceptance. Innovative approaches to enhance closed-loop performance are discussed and we also present the outlook and strategies used to ease clinical adoption of closed-loop systems.
Today the increased competitiveness of global market forces companies to provide products and services with quality standards ever higher at lower costs. In this sense, both technological development and innovation, a...
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Today the increased competitiveness of global market forces companies to provide products and services with quality standards ever higher at lower costs. In this sense, both technological development and innovation, as strategic factor, drive companies to invest in development of smart applications that allows to increase global efficiency and improves the quality, understood as satisfaction of the client. In Continuous Casting Production (CCP), for example, this means Slag Sensing System (SSS) improvement in order to obtain better purity of molten steel and at the same time to reduce the maintenance costs associated with the implantation of casting. After an overview of SSS currently used in industry, this paper deals with vibrational analysis and characterization of the process of CCP to develop an on-line real-time application of vibrational method for slag detection. At first time domain and frequency domain analysis is performed to characterize the vibrations associated with the plant, subsequently, on the base of obtained results, a control algorithm is developed and the related software is coded, in order to drive the closing of the nozzle valve in a real industrial application. (C) 2016, IFAC (International Federation of Automatic control) Hosting by Elsevier Ltd. All rights reserved.
In this paper, we propose a novel linear matrix inequality-based nonlinear adaptive robust control algorithm to design the attitude and position controllers for an X-configuration quadrotor helicopter. The inner loop ...
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In this paper, we propose a novel linear matrix inequality-based nonlinear adaptive robust control algorithm to design the attitude and position controllers for an X-configuration quadrotor helicopter. The inner loop of the autopilot controls the attitude and altitude of the quadrotor, and the outer loop controls its position in the Earth-fixed coordinate frame. By assuming knowledge of the bounds of the quadrotor's uncertain parameters (e.g., mass and moments of inertia) and predetermined bounds on the external and unstructured disturbances (e.g., wind gusts and unmodeled dynamics), we attain a guaranteed transient and steady-state tracking performance. We demonstrate the performance of the controllers via two illustrative examples. In the first example mission, the quadrotor follows an altitude reference trajectory in the presence of wind gusts and delivers a package of uncertain mass midflight. The second example presents an autonomous waypoint flight in the presence of wind disturbances. The results of our simulations indicate that our controller design is useful for a variety of quadrotor applications, including precise trajectory tracking, autonomous waypoint navigation in the presence of disturbances, and package delivery without loss of performance.
A multiple electrodynamic tether (multi-EDT) propulsion system is especially apt for chip-scale spacecraft near Earth or other bodies with magnetic fields and ionospheres. Multiple electrodynamic tethers acting on one...
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A multiple electrodynamic tether (multi-EDT) propulsion system is especially apt for chip-scale spacecraft near Earth or other bodies with magnetic fields and ionospheres. Multiple electrodynamic tethers acting on one spacecraft allow instantaneous action in five degrees of freedom (5 DOFs). Specific configurations of multiple tethers can guarantee control in any orientation, allowing simpler and more agile control than a traditional single EDT. The advantage of a multi-EDT system is that there are multiple directions of action available at a single time. This allows more precise control and removes some of the controller dependence on orbital geometry.
A motor controller based on STM32F103 MCU, which is designed for the patient transfer apparatus is presented. Firstly, according to the working principle of the apparatus, the power of the motor is calculated, and the...
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ISBN:
(纸本)9781509041022
A motor controller based on STM32F103 MCU, which is designed for the patient transfer apparatus is presented. Firstly, according to the working principle of the apparatus, the power of the motor is calculated, and the selection of the motor is carried out. According to the chosen motor, the controller's hardware circuit design is carried out. According to the need of apparatus control, the controller adopts the double loop speed control algorithm which is added with the speed forward feed control. The controller has two operation modes, torque mode and speed mode, and the two modes can be switched flexibly during the work process. The controller uses CAN bus communication, makes the network control more easily. A controller parameters debug software programed with QT makes it easy to setup the controller parameters. The software can greatly shorten the time of parameter adjustment. Finally, the related experiment is carried out, and the result indicates that the controller can complete the control task well.
One of the most important factors in the successful application of unmanned vehicles is the ability to determine where a vehicle is in relation to its local environment. While GPS technology works well in most locatio...
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ISBN:
(纸本)9781509009701
One of the most important factors in the successful application of unmanned vehicles is the ability to determine where a vehicle is in relation to its local environment. While GPS technology works well in most locations, the satellite coverage necessary for this technology to function is not available in cluttered environments and inside buildings. Current technological workarounds involve high resolution image processing, which is expensive in terms of both monetary and computational cost. Our project team is working to develop an alternative localization solution for drones that uses low cost lasers and off-the-shelf components. The technique involves setting up two or more "lighthouse" beacons in a controlled environment. The beacons will pulse invisible infrared light from LEDs and sweep vertical sheets of infrared lasers around the environment. Photodiodes installed on the UGV will respond to these light sources and pass this information to a processor. Based on the timing of the diode response, the angle between the lighthouse and the diodes can be determined. When combined with ultrasonic altitude data, these angles can be processed to determine the location of the diodes and subsequently the location and orientation of the UGV. The accuracy and precision of the final lighthouse system will be assessed to determine its usefulness for localizing drones in a controlled environment. The end goal of the technical project is to design a system that will facilitate the automated driving of a UGV based on localization data from the lighthouse system while being scalable for future implementation in 3D applications.
The paper describes new engineering solutions at developing a test bench for studying experimental models of reciprocating electrical machines, as well as the hardware-software control system. A crank mechanism was us...
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ISBN:
(纸本)9781509013227
The paper describes new engineering solutions at developing a test bench for studying experimental models of reciprocating electrical machines, as well as the hardware-software control system. A crank mechanism was used when developing the bench to create hydraulically driven reciprocating motion. The designed hardware-software system allows for controlling the bench and the test subject due to a large number of inputs and outputs of various applications. The sensors integrated into the bench enable a complete test picture and sufficient amount of high-precision data. A high flexibility of the bench and the test subject control algorithm allows for conducting a wide range of various tests of electrical products.
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