A discrete-time sliding mode with block control aided design is applied to a nonlinear discrete-time induction motor model where the load torque is considered as unknown perturbation. With full state measurements, both rotor speed and rotor flux amplitude tracking objectives are satisfied. Then, a reduced order observer is implemented where speed and current measurements provide the observation...

This paper investigates a novel direct torque control (DTC) for a sensorless interior permanent magnet synchronous motor (PMSM) based on a sliding mode technique (SMC). The speed and position of the interior PMSM are estimated online based on active flux concept. To overcome the large ripple content associated with the direct torque, a torque/flux sliding mode controller has been employed. Two ...

Stick-slip friction was observed in articular cartilage under certain loading and sliding conditions and systematically studied. Using the Surface Forces Apparatus, we show that stick-slip friction can induce permanent morphological changes (a change in the roughness indicative of wear/damage) in cartilage surfaces, even under mild loading and sliding conditions. The different load and speed re...

This paper discusses the nonlinear control problem for variable-speed wind energy conversion system. Due to the stochastic operating conditions and the inevitable uncertainties inherent in the system, linear control method comes at the price of poor system performance and low reliability. So, it first develops a detailed model of variable-speed wind energy conversion system, which incorporated ...

The friction and wear performance of ultra high molecular weight polyethylene(UHMWPE) and pure poly-ether-etherketone(PEEK) polymers were comparatively evaluated under dry sliding and cacao drops lubrication. The sliding experiments were carried out on a pin-on-disc tribometer. The contact configuration used was a polymer pin on a rotating stainless steel disc. Wear tests were carried out at ro...

Observation of a tribo-induced transition from solid to liquidlike behavior is reported for a scanning tunneling microscope tip in sliding contact with an indium electrode of a quartz crystal microbalance (QCM). In particular, at a sufficiently high asperity sliding speed (about 1 m/s) and/or sample temperature, a change in the contact mechanics is observed that is consistent with melting in te...

This paper presents a sliding mode controller for a narrow tilting three wheeled vehicle. A dynamic model of eighteenth order is presented for simulation purposes only. Design and analysis are based on a simpler third order model of a bicycle. The validity of this simplification is verified through simulations. Because of the flatness of the bicycle, trajectories given by a presumed driver are ...

Models predict that dynamic shear ruptures during earthquake faulting occur as either sliding cracks, where a large section of the interface slides behind a fast-moving rupture front, or self-healing slip pulses, where the fault relocks shortly behind the rupture front. We report experimental visualizations of crack-like, pulse-like, and mixed rupture modes propagating along frictionally held, ...

To satisfy with the high-power control of the asynchronism motor control drive system, this paper devised a novel reaching law of sliding mode variable structure control strategy and analysed this control strategy for vector control system of asynchronism motor and the high-frequency chattering phenomenon in traditional sliding mode controllers. The simulation results demonstrate that the contr...

Novel induction motor control optimizing both torque response and efficiency is proposed in the paper. The main contribution of the paper is a new structure of rotor flux observer aimed for the speed-sensorless operation of induction machine servo-drive at both, low and high speed, where rapid speed changes can occur. The control differs from the conventional field-oriented control. Stator and ...