Fluid film forces are generated in multirecess journal bearings by two types of lubrication mechanism: the hydrostatic lubrication in the bearing recesses and hydrodynamic lubrication in the bearing lands, when operating in rotation. The combination of both lubrication mechanism leads to hybrid journal bearings (HJB). When part of hydrostatic pressure is also dynamically modified by means of hy...

The increasing size of wind farms requires power system stability analysis including dynamic models of wind Power generation. Nowadays, the most widely used generator type for units above 1MW is the doubly-fed induction machine. The behavior of these machines during grid failure is an important issue. In this paper, a theoretical analysis of the dynamic behavior of the doubly fed induction gene...

Strain measurement and vibration analysis of a rotating blade are critical for the progress in improvements of the performance of machines. Since traditional sensors and measurement methods have difficulty measuring the rotor blade’s dynamic strain and vibration, the search for new measurement methods has become an urgent task in rotor machine monitoring and diagnosis. This paper presents a new...

Small unmanned four-rotor helicopter (four-rotor) is a kind of noncoaxial, multirotor, dished vehicle with vertical take off and landing (VTOL) ability. Due to the complexity, strong coupling and sensitivity effects on the environment of four-rotor’s dynamic model, the controller must have high quality of robust and adaptive. According to these requirements, a lot of control theory have been pr...

Accurate positioning of the motor requires high control performance for low-speed operation and motor’s parameter perturbation. In the AC motor vector control technology, the nonsingular higher-order terminal sliding mode observer of Insertion Permanent Magnet Synchronous Motor (IPMSM) is put forward based on the object current and voltage values to obtain the rotor position and speed signa. Th...

In this study, dynamic behavior of safety mechanism of a mechanical controller is investigated using 3D-FE simulation. This paper is concentrated on controller of a high acceleration projectile. The controller is located in the top of the projectile. Safety mechanism is divided to deformable and rigid parts. Deformable and rigid parts are simulated in Abaqus and Adams commercial soft wares; res...

In practice, it is usually difficult to obtain the physical model of nonlinear, rotor-bearing systems due to uncertain nonlinearities. In order to solve this issue to conduct the analysis and design of nonlinear, rotor-bearing systems, in this study, a data driven NARX (Nonlinear Auto-Regressive with exogenous inputs) model is identified. Due to the lack of the random input signal which is requ...

This paper describes an active control method to prevent unwanted nonlinear vibration response modes of a rotordynamic system. Nonlinear stiffness of components that support or surround a machine rotor can cause a response branch that extends critical vibration (resonance) over a wide interval of rotational speeds. Within this interval, jump transitions between alternative low amplitude and hig...

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...

This paper presents the study of a single-phase synchronous motor with permanent magnets (PM) using some computer programs. This motor type is used especially in household applications, and it has a low power. It is known that PM synchronous motors have a great advantage consisting in the lack of rotor losses. For this motor the starting problem has been solved performing a variable air gap und...