Search results for "Biot"
showing 10 items of 8384 documents
Advances on mechanics, design engineering and manufacturing
2018
The theme of the present editorial is dedicated to the“Advances on Mechanics, Design Engineering and Manufac-turing” that emerge in different engineering and architecturalfields.The theme has been chosen as leitmotiv of a series ofevents that have been organized by three societies operatingin Italy, Spain and France, respectively: ADM (Associ-azione nazionale Disegno e Metodi dell’ingegneria indus-triale), INGEGRAF (Asociación Española de IngenieríaGráfica and AIP-PRIMECA (Ateliers Inter-établissementsde Productique—Pôles de Resources Informatiques pour laMECAnique). Since 2014, a series of JCM conferences havebeen organized. JCM is the acronym of “Joint Conference onMechanics, Design Engin…
Consensus-Based Distributed State Estimation of Biofilm in Reverse Osmosis Membranes by WSNs
2017
The appearance of biofilm has become a serious problem in many reverse osmosis based systems such as the ones found in water treatment and desalination plants. In these systems, the use of traditional techniques such as pretreatment or dozing biocides are not effective when the biofilm reaches an irreversible attachment phase. In this work, we present a framework for the use of a WSN as an estimator of the biofilm evolution in a reverse osmosis membrane so that effective solutions can be applied before the irreversible phase is attained. This design is addressed in a complete distributed and decentralized fashion, and subject to realistic constraints where cooperation between nodes is perfo…
Load Torque Estimation Method to Design Electric Drivetrains for Offshore Pipe Handling Equipment
2016
One of the main design objectives for electric drivetrains operating in offshore drilling equipment is to keep them as small, yet as effective, as possible, to minimize space they occupy on drill floor and maximize their performance. However, practical experience shows that typically choices made by design engineers are too conservative due to the lack of enough data characterizing load conditions. This results in too costly and too heavy selected components. Therefore, in the current paper we present a method to estimate required full-scale motor torque using a scaled down experimental setup and its computational model. A gripper arm of an offshore vertical pipe handling machine is selecte…
SHEAR COMPLIANCE AND SELF WEIGHT EFFECTS ON TRACTION BELT MECHANICS
2007
The transverse elastic deflection of a traction belt along the free span depends mainly on the flexural stiffness, but may be significantly influenced by the distributed weight and the shear compliance, which affect together the width of the arc of contact. In particular, the shear compliance yields a virtual decrease of the flexural stiffness, flattens the free span and increases the wound regions, to the advantage of the transmissible torque. Moreover, the tensioning of a given belt may be somewhat larger, in comparison with the ideal circular-straight path with the same centre distance, because of the increased length of the deflected belt trajectory due to gravity. The present paper ad…
Novel concept for stabilising a hydraulic circuit containing counterbalance valve and pressure compensated flow supply
2016
In this paper, a novel concept for stabilising a hydraulic system containing a counterbalance valve and a pressure compensated flow supply is presented. The concept utilizes a secondary circuit where a low-pass filtered value of the load pressure is generated and fed back to the compensator of the flow supply valve. The novel concept has been investigated theoretically and experimentally. A linear model has been developed to verify the improved stability conditions. The novel concept has been implemented on a single boom actuated by a cylinder. The results show that the pressure oscillations in an otherwise unstable system can be suppressed with the novel concept. This happens without any c…
On break-away forces in actuated motion systems with nonlinear friction
2017
The phenomenon of so-called break-away forces, as maximal actuation forces at which a sticking system begins to slide and thus passes over to a steady (macro) motion, is well known from engineering practice but still less understood in its cause-effect relationship. This note analyzes the break-away behavior of systems with nonlinear friction, which is analytically well-described by combining the Coulomb friction law with rate-independent presliding transitions and, when necessary, Stribeck effect of the velocity-weakening steady-state curve. The break-away conditions are harmonized with analytic form of the system description and shown to be in accord with a relationship between the varyin…
Learning of Cooperative Behaviour in Robot Populations
2016
This paper addresses convergence and equilibrium properties of game theoretic learning algorithms in robot populations using simple and broadly applicable reward/cost models of cooperation between robotic agents. New models for robot cooperation are proposed by combining regret based learning methods and network evolution models. Results of mean-field game theory are employed in order to show the asymptotic second moment boundedness in the variation of cooperative behaviour. The behaviour of the proposed models are tested in simulation results, which are based on sample networks and a single lane traffic flow case study.
Regularized LMS methods for baseline wandering removal in wearable ECG devices
2016
The acquisition of electrocardiogram (ECG) signals by means of light and reduced size devices can be usefully exploited in several health-care applications, e.g., in remote monitoring of patients. ECG signals, however, are affected by several artifacts due to noise and other disturbances. One of the major ECG degradation is represented by the baseline wandering (BW), a slowly varying change of the signal trend. Several BW removal algorithms have been proposed into the literature, even though their complexity often hinders their implementation into wearable devices characterized by limited computational and memory resources. In this study, we formalize the BW removal problem as a mean-square…
Trends in Metal Cutting Theory and Practice
2017
This chapter provides the state-of-the-art manufacturing systems that utilize various machining technologies in different manufacturing sectors. It highlights the challenges of the 21st-century manufacturing environment and characterizes numerous driven factors in modern machining technologies. They include more-established technologies, such as High-Speed Machining/Cutting, High-Performance Machining/Cutting, High-Efficiency Machining or currently developed ones, such as resource- and energy-efficient (generally sustainable) and hybrid machining. Practical examples and charts that document their importance in modern manufacturing are provided. Finally, some important future trends are over…
Identification and control design for path tracking of hydraulic loader crane
2017
The controlled operation of hydraulic machines with multiple degrees of freedom is challenging due to complex nonlinear dynamics of cylinder actuators, in addition to multibody dynamics like in the case of hydraulic manipulators. This paper addresses the system identification and control design for path tracking of a standard hydraulic loader crane. The kinematics of the crane is solved for operation in the vertical plane and generation of trajectories for the tool tip to be followed. A frequency response measurements and analysis have been done for dynamics modeling of both hydraulic cylinders actuating main boom and jib. The static dead-zone type input non-linearity has been identified an…