Search results for "automatic"
showing 10 items of 730 documents
Peak Power Demand and Energy Consumption Reduction Strategies for Trains under Moving Block Signalling System
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/940936 Open Access In the moving block signalling (MBS) system where the tracking target point of the following train is moving forward with its leading train, overload of the substations occurs when a dense queue of trains starts (or restarts) in very close distance interval. This is the peak power demand problem. Several methods have been attempted in the literature to deal with this problem through changing train's operation strategies. However, most existing approaches reduce the service quality. In this paper, two novel approaches - …
Neural based MRAS sensorless techniques for high performance linear induction motor drives.
2010
This paper proposes a neural based MRAS (Model reference Adaptive System) speed observer suited for linear induction motors (LIM). Starting from the dynamical equation of the LIM in the synchronous reference frame in literature, the so-called voltage and current models of the LIM in the stationary reference frame, taking into consideration the end effects, have been deduced. Then, while the inductor equations have been used as reference model of the MRAS observer, the induced part equations have been discretized and rearranged so to be represented by a linear neural network (ADALINE). On this basis, the so called TLS EXIN neuron has been used to compute on-line, in recursive form, the machi…
Minimum Losses Reconfiguration of MV Distribution Networks through Local Control of Tie Switches
2002
This paper deals with the problem of optimal reconfiguration of radial distribution networks for minimum loss operation. The proposed control strategy of the open-closed status of the tie-switches is distributed, since every MV/LV node is provided with local controllers having some measured entities as input. It also does not prevent the system from the future implementation of centralized control; instead it may represent the first step toward a complete automation of the distribution system. The proposed strategy is indeed organized in hierarchic levels, the highest of which may be in the future a central control. After introducing the general problem of networks reconfiguration, a review…
Experimental analysis of occupational whole-body vibration exposure of agricultural tractor with large square baler
2015
Abstract This study investigates longitudinal whole-body vibration in agricultural tractors powering a large square baler. The aim is to test the hypothesis that four-wheel drive has an influence on the longitudinal dynamic response. A number of experimental measurements are carried out on a specific vehicle combination driving uphill and downhill. The whole-body vibration exposure is measured at the operator seat under different conditions. The statistic results show a significant difference on the whole-body vibration exposure depending on operating conditions. Driving uphill and downhill with four-wheel drive activated showed the highest difference with increased vibration level at downh…
Design and control of a novel 3D casting manipulator
2010
This paper focuses on casting manipulation and presents an innovative mechanism that allows objects placed in a three-dimensional space to be reached with a relatively small robot. Casting manipulation is a technique by which a robotic end-effector is thrown and its ballistic flight is controlled through a tether cable so as to reach a target object. Previous work presented a solution that is viable only when the position of the target object is perfectly known or aligned with the throwing plane. Our work extends the technique by use of a novel mechanical design of the arm, and a suitable control scheme for the flight of the end-effector, which makes it applicable for objects placed at gene…
A Rough-Terrain Casting Robot for the ESA Lunar Robotics Challenge
2009
This paper describes the design and implementation of DAVID, a lunar vehicle developed for the European Space Agency (ESA) Lunar Robotics Challenge, presenting severe terrain negotiation and sample acquisition challenges. We discuss in some detail two of the main innovative aspects of our entry to the challenge, i.e. the locomotion system and the sample acquisition system. Motivated by the challenge specifications, a range of different locomotion systems were considered, among which we chose a simple, rugged and effective wheeled system. We provide an account of the choice of five different types of wheels, which were designed, analyzed and experimentally tested in conditions similar to the…
Visual-based Feedback Control of Casting Manipulation
2006
In this paper, we present a method to control casting manipulation by means of real-time visual feedback. Casting manipulation is a technique to deploy a robotic end-effector at large distances from the robot’s base, by throwing the end-effector and controlling its ballistic flight using forces transmitted through a light tether connected to the end-effector itself. The tether cable can also be used to retrieve the end-effector and exert forces on the robot’s environment. Previous work has shown that casting manipulation is able to catch objects at a large distance, proving it viable for applications such as sample acquisition and return, rescue, etc. In previous experiments, the position o…
Dynamic Distributed Intrusion Detection for Secure Multi-Robot Systems
2009
A general technique to build a dynamic and distributed intrusion detector for a class of multi–agent systems is proposed in this paper, by which misbehavior in the motion of one or more agents can be discovered. Previous work from the authors has focused on how to distinguish the behavior of a misbehaving agent in a completely distributed way, by developing a solution where agents act as local monitors of their neighbors and use locally sensed information as well as data received from other monitors at a particular time. In this work, we improve the system detection capability by allowing monitors to use information collected at different instants and thus realizing a dynamic state observer…
Frequency stability in microgrid: control strategies and analysis of BESS aging effects
2016
In order to ensure a thorough analysis, all components placed in a microgrid would have to be considered to guarantee an effective energy management. To this aim, various algorithms are used both to preserve and restore power systems after significant disturbances. However, these models frequently do not evaluate components performance decline with the age and, consequently, they don't consider actual values during microgrid analysis, potentially affecting obtained results. In particular, evaluating energy storage systems aging and their effects has rarely been addressed in prior works. The present article proposes a model to maintain power system/microgrid stability after disturbances usin…
Speed and rotor flux estimation of induction motors via on-line adjusted extended kalman filter
2006
This paper deals with the estimation of speed and rotor flux of induction motors via Extended Kalman Filter (EKF) with on-line adjusting of the system noise covariance matrix. The predictor of EKF consists of a discrete time model obtained by means of a second order discretization of the original nonlinear model of the induction motor. In order to obtain accurate estimation of the above mentioned variables, the load torque is included in the state variables and then estimated. Three different system noise models are also illustrated and compared each other by simulations carried out in Matlab/Simulink environment. For one of these models, EKF is adjusted on-line by means of an additional PI…