This dissertation presents a control law for helicopters to reduce vibration and to increase damping using individual blade control. control synthesis is used to develop a robust controller usable in different operating conditions with different helicopter flight speeds. The control design is applied in simulation to the four-blade BO 105 helicopter rotor, which is equipped with an individual b...

An iterative approach for the determination of an input-output inversion feedforward control law for residual vibration reduction is proposed in this paper. In particular, point-topoint motion planning of vibratory servosystems is considered. The method aims at estimating recursively the parameters of the system in order to determine the exact command input to be applied to the control system i...

This paper derives a jerk-shaped profile to address the vibration reduction of underdamped flexible dynamics of motion system. The jerk-limited profile is a widespread smooth command pattern used by modern motion systems. The ability of the jerk-limited profile to cancel the residual vibration of an undamped flexible mode is clearly explained using an equivalent continuous filter representation...

Equal channel angular pressing (ECAP) is one of the most prominent procedures for achieving ultra-fine grain (UFG) structures among the various severe plastic deformation (SPD) techniques. In this study, the effect of ultrasonic vibration on deformation behavior of commercial pure aluminum in the ECAP process is analyzed successfully using three dimensional (3D) by finite element methods (FEMs)...

Some near-regular mechanical systems involve global deviations from their corresponding regular system. Despite extensive research on vibration analysis (eigensolution) of regular and local near-regular mechanical systems, the literature on vibration analysis of global near-regular mechanical systems is scant. In this paper, a method for vibration analysis of such systems was developed using Kr...

Diffusion tensor imaging is widely used in research and clinical applications, but still suffers from substantial artifacts. Here, we focus on vibrations induced by strong diffusion gradients in diffusion tensor imaging, causing an echo shift in k-space and consequential signal-loss. We refined the model of vibration-induced echo shifts, showing that asymmetric k-space coverage in widely used P...

Due to the periodic movement of the piston in the reciprocating pump, the fluid will cause 8 pressure pulsation, and the vibration of the pipeline will lead to instrument distortion, pipe failure 9 and equipment damage. Therefore, it is necessary to study the vibration phenomena of the 10 reciprocating pump pipeline based on the pressure pulsation theory. This paper starts from the 11 reciproca...

In this article, the H∞ optimization design of a hybrid vibration absorber (HVA), including both passive and active elements, for the minimization of the resonant vibration amplitude of a single degree-of-freedom (SDOF) vibrating structure is derived by using the fixed-points theory. The optimum tuning parameters are the feedback gain, the tuning frequency, damping and mass ratios of the absorb...

natural vibration analysis of plates represents an important issue in engineering applications. in this paper, a new and simplify method for vibration analysis of circular and rectangular plates is presented. the design of an effective robust controller, which consistently attenuates transverse vibration of the plate caused by an external disturbance force, is given. the dynamics of the plate i...

Vibration was applied to the tendon of flexor carpi radialis while recording the EMG of the wrist flexors in 29 Parkinsonian patients. Cessation of the vibration led to a small short-latency (approximately 25 ms) reduction in the level of activity which did not differ in magnitude from the normal. Moreover, there was no sign of any subsequent long-latency reduction of activity. Thus the maintai...