This paper investigates the use of dyadic wavelets for the control of multifrequency rotor vibration. A scheme for real-time control of rotor vibration using an adaptive wavelet decomposition and reconstruction of time-varying signals is proposed. Quasi-periodic control forces are constructed adaptively in real-time to optimally cancel vibration produced by nonsmooth disturbance forces. Control...

A computational study of helicopter vibration and rotor shaft power reduction is conducted using activelycontrolled trailing-edge flaps (ACFs), implemented in both single and dual flap configurations. Simultaneous vibration reduction and performance enhancement is demonstrated under level flight condition at high advance ratios, where dynamic stall effects are significant. Power reduction is ac...

H∞ controller for active magnetic bearings (AMBs) with flexible rotor system was designed in this paper. The motion equations of AMBs and flexible rotor system are built based on finite element methods (FEM). Weighting function matrices of H∞ controller for AMBs are studied for both the sensitivity and the complementary sensitivity of H∞ control theory. The simulation shows that the H∞ control ...

Abstract: The proposed method allows determining the level of wear of the bearings of electric machines by means of rotor radial displacement during operation. Measurement is effected by non-contact method and optoelectronic sensor which converts the rotor mechanical motion into electric signal. Received informational signal is recorded and processed by computer system. Based on the processed i...

This report contains the results of a full-scale experimental feasibility study of rotor isolation employing the Dynamic Antiresonant Vibration Isolator (DAVI) . The full-scale experiments were performed on a UH-2 helicopter fuselage isolated from a simulated rotor and transmission. Tests were conducted for three directions of vibratory input at the hub on the nonisolated vehicle and then compa...

An aeroelastic model of a smart rotor system (which incorporates blade-mounted trailing-edge flap actuators and conventional root pitch actuation) is presented in linear time invariant state space form. The servo-flap deflections are modeled as producing incremental lift and moment variations, so that any linear aerodynamic actuator can be evaluated. This smart rotor model is used to conduct pa...

different methods for detecting broken bars in induction motors can be found in literature. many of these methods are based on evaluating special frequency magnitudes in machine signals spectrums. current, power, flux, etc are among these signals. frequencies related to broken rotor fault depend on slip. in industrial environment due to some phenomena - such as load oscillation, other faults an...

The Active Vibration and Noise Reduction (AVINOR) aeroelastic simulation code for helicopter rotor blades is described. AVINOR is a research code that has been developed at UCLA and the University of Michigan for the purpose of conducting computationally efficient aeroelastic response analyses while maintaining a level of fidelity so as to be suitable for preliminary design of helicopter rotor ...

Abstract: Bottom-fixed vertical rotating devices are widely used in industrial and civilian fields. The free upside of the rotor will cause vibration and lead to noise and damage during operation. Meanwhile, parameter uncertainties, nonlinearities and external disturbances will further deteriorate the performance of the rotor. Therefore, in this paper, we present a rotor orientation control sys...

Misalignment and unbalance is the most cause of machine vibration. An unbalanced rotor always cause more vibration and generates excessive force in the bearing area and reduces the life of the machine. Understanding and practicing the fundamentals of rotating shaft parameters is the first step in reducing unnecessary vibration, reducing maintenance costs and increasing machine uptime. In this p...