Search results for " vibration"
showing 10 items of 296 documents
PVDF based vibration measurements and their correlation with torque estimation in a FOC induction motor drive
2008
This paper presents a study concerning the vibrations generated by an induction motor drive controlled by field oriented control algorithm (FOC). The aim of the study is to identify suitable measurement points and analysis techniques in order to achieve information about vibration generated by an electric drive. Vibrations take origin both by the torque generated by the motor and the motor supply through an inverter, then they are transmitted to neighbouring structures. Torque is estimated on the basis of the estimated flux linkage; vibrations have been both measured and analysed numerically by FEM at two points of the cradle. The numerical and experimental analysis have been carried out fo…
Vibration analysis for bearing fault detection and classification using an intelligent filter
2014
Abstract This paper proposes an intelligent method based on artificial neural networks (ANNs) to detect bearing defects of induction motors. In this method, the vibration signal passes through removing non-bearing fault component (RNFC) filter, designed by neural networks, in order to remove its non-bearing fault components, and then enters the second neural network that uses pattern recognition techniques for fault classification. Four different categories include; healthy, inner race defect, outer race defect, and double holes in outer race are investigated. Compared to the regular fault detection methods that use frequency-domain features, the proposed method is based on analyzing time-d…
Fatigue life under non-Gaussian random loading from various models
2004
Fatigue test results on the 10HNAP steel under constant amplitude and random loading with non-Gaussian probability distribution function, zero mean value and wide-band frequency spectrum have been used to compare the life time estimation of the models proposed by Bannantine, Fatemi–Socie, Socie, Wang–Brown, Morel and Łagoda–Macha. Except the Morel proposal which accumulates damage step by step with a proper ethodology, all the other models use a cycle counting method. The rainflow algorithm is used to extract cycles from random histories of damage parameters in time domain. In the last model, where a strain energy density parameter is employed, additionally spectral method is evaluated for …
Laws, Regulations, Standards, and Guidelines for the Protection of Man Against Mechanical Vibration
1986
Regulations that serve to protect workers from the dangers arising from mechanical vibration have been established by the legislators and agencies responsible for work protection, such as ministries of labor and social affairs and industrial insurance organizations. Furthermore, international agreements have also established such protective measures. The corresponding laws, rules or agreements relate to: 1. Occupational diseases 2. Criteria for the evaluation of risk from mechanical vibration and the establishment of exposure limit values 3. Guidelines for the measurement and evaluation of vibration 4. Medical examinations before employment and regular health examinations 5. Technical and o…
Vibration control for adjacent structures using local state information
2014
In this paper, a novel strategy for structural vibration control of multi-structure systems is presented. This strategy pays particular attention to mitigating negative interstructure interactions. Moreover, it is based on recent advances in static output–feedback control, which make possible the efficient computation of decentralized velocity-feedback controllers by solving a single-step optimization problem with Linear Matrix Inequality constraints. To illustrate the main ideas, a local velocity-feedback energy-to-peak controller is designed for the seismic protection of a two-building system. This controller is remarkably effective and extremely simple. Moreover, it can also be implement…
Passive-damping design for vibration control of large structures
2013
In this work, a systematic strategy to design passive damping systems for structural vibration control is presented. The proposed design methodology is based on the equivalence between decentralized static velocity-feedback controllers and passive damping systems. By using recent developments in static output-feedback control, the design of passivedamping systems can be formulated as a single optimization problem with Linear Matrix Inequality constraints. Moreover, this optimization problem can be efficiently solved with standard numerical tools, even for large dimension systems. Due to its computational effectiveness, the proposed methodology can be applied to the design of passive damping…
ARIANNA: a smartphone-based navigation system with human in the loop
2014
In this paper we present a low cost navigation system, called ARIANNA, primarily designed for visually impaired people. ARIANNA (pAth Recognition for Indoor Assisted NavigatioN with Augmented perception) permits to find some points of interests in an indoor environment by following a path painted or sticked on the floor. The path is detected by the camera of the smartphone which also generates a vibration signal providing a feedback to the user for correcting his/her direction. Some special landmarks can be deployed along the path for coding additional information detectable by the camera. In order to study the practical feasibility of the ARIANNA system for human users that want to follow …
Monte Carlo simulation for the response analysis of long-span suspended cables under wind loads
2004
This paper presents a time-domain approach for analyzing nonlinear random vibrations of long-span suspended cables under transversal wind. A consistent continuous model of the cable, fully accounting for geometrical nonlinearities inherent in cable behavior, is adopted. The effects of spatial correlation are properly included by modeling wind velocity fluctuation as a random function of time and of a single spatial variable ranging over cable span, namely as a one-variate bi-dimensional (1V-2D) random field. Within the context of a Galerkin`s discretization of the equations governing cable motion, a very efficient Monte Carlo-based technique for second-order analysis of the response is prop…
Investigation of motor current signature and vibration analysis for diagnosing rotor broken bars in double cage induction motors
2012
This paper investigates the detectability of rotor broken bars in double cage induction motors using current signature and vibration analysis techniques. Double cage induction motors are commonly used for applications where successive loaded starts-up are mandatory. Experimental results were performed under healthy and faulty cases, and for different load conditions using each technique. Rotor broken bars fault detection based on sideband current components may fails due to the presence of inter bar currents that reduce the degree of rotor asymmetry, yielding to a decrease of the magnitude of these spectral components. But inter bar currents produce core vibrations in the axial direction, w…
Vibration signature analysis for rotor broken bar diagnosis in double cage induction motor drives
2013
The paper investigates the diagnosis of rotor broken bars in field oriented controlled (FOC) double cage induction motor drives, using current and vibration signature analysis techniques. The Impact of the closed loop control system cannot be neglected when the detection of asymmetries in the machine are based on the signature analysis of electrical variables. The proposed diagnosis approach is based on optimized use of wavelet analysis by a pre-processing of phase current or axial/radial vibration signals. Thus, the time evolution of the tracked rotor fault components can be effectively analyzed. This paper shows also the relevance of the fault components computed from axial vibration sign…