Multi rotor UAVs offer great potential wide range of challenging applications due to the high manoeuvrability and to the potential to hover, take off and fly in small areas. Nevertheless, their design is in some way critical. The main concern is their inadequate level of handling qualities due to the intrinsic instabilities of this type of small size vehicles. A specific hardware with a control...

Squeeze Film Dampers (SFD) are commonly used for passive vibration control of rotor-bearing systems. The Magnetorheological (MR) and Electrorheological (ER) fluids in SFDs give a varying damping characteristic to the bearing that can provide active control schemes for the rotor-bearing system. A common way to model an MR bearing is implementing the Bingham plastic model. Adding this model to th...

This paper presents a new adaptive Sliding-Mode flux observer for speed sensorless and rotor flux control of three-phase induction motor (IM) drives. The motor drive is supplied by a three-level space vector modulation (SVM) inverter. Considering the three-phase IM Equations in a stator stationary two axis reference frame, using the partial feedback linearization control and Sliding-Mode (SM) c...

All single-rotor helicopters require an antitorque device (usually a tail-rotor system) to counter the fuselage’s reaction to the rotation of the main-rotor system. From 1988 through 1993, there were 74 U.S. civil turbine-engine helicopter accidents involving the helicopter’s tail-rotor system, according to statistics from the U.S. National Transportation Safety Board (NTSB) and the U.S. Federa...

Since many rotor systems normally operate above their critical speeds, the problem of accelerating the machine through its critical speeds without excessive vibration draws increasing attention. This paper provides an analytical imbalance response of the Jeffcott rotor under constant acceleration. The response consists of three parts: transient vibration due to the initial condition of the roto...

Direct torque control (DTC) of induction motors (IMs) requires an accurate knowledge on the amplitude and angular position of the controlled flux in addition to the information related to angular velocity for velocity control applications. However, unknown load torque and uncertainties related to stator/rotor resistances due to operating conditions constitute major challenges for the performanc...