Aeroelastic qualification requirements are typically met by sizing aircraft to achieve adequate stability margins and keep peak gust responses below specified thresholds. A possible alternative approach is delaying flutter alleviating response embedding dissipative materials into structural components. This requires accurate damping models applicable the analysis of complex configurations. In t...

Momentum is a simple and widely used trick which allows gradient-based optimizers to pick up speed in low curvature directions. Its performance depends crucially on a damping coefficient β. Large β values can potentially deliver much larger speedups, but are prone to oscillations and instability; hence one typically resorts to small values such as 0.5 or 0.9. We propose Aggregated Momentum (Agg...

Force control implemented by a passive mechanical device (perhaps a wrist) has inherent advantages over active implementations. A passive mechanical device can regain some of the versatility of its active counterpart if it incorporates mechanical elements with programmable parameters, e.g. damping coefficients or spring stiffnesses. We wish to characterize the range of accommodation matrices th...

In this paper an optimal damped input filter is designed based on a Genetic Algorithm (GA) for an electrolytic capacitor-less AC-AC converter. Sufficient passive damping and minimum losses in passive damping elements, minimization of the filter output impedance at the filter cut-off frequency, minimization of the DC-link voltage and input current fluctuations, and minimization of the filter cos...

In this paper, the advantage of an adaptive damping system is presented. A damper with variable stiffness is tuned based on estimates of the real-time frequency response, facilitating optimal vibration mitigation. The performance of the developed routines is investigated on an existing tied arch railway bridge. Based on previous field measurements, resonant behaviour of several hangers was foun...

additional dampers are employed in order to decrease the dynamic response of structure against the earthquake and wind loading recently. in this study, two types of systems related to waste of inactive energy, i.e. frictional damper which is categorized in dampers dependent on movement and viscoelastic damper which is categorized in dampers dependent on velocity, in making steel structures resi...

This paper studies the feedback structure associated with piezoelectric shunt damping systems and introduces a new impedance structure for multi-mode piezoelectric shunt damping. The impedance is shown to be realizable using passive circuit components and digital implementation of the associated admittance transfer function is discussed. (Some figures in this article are in colour only in the e...

The biomechanical properties of an animal's locomotor structures profoundly influence the relationship between neuromuscular inputs and body movements. In particular, passive stability properties are of interest as they may offer a non-neural mechanism for simplifying control of locomotion. Here, we hypothesized that a passive stability property of animal flight, flapping counter-torque (FCT), ...

We consider here passive mechanical wrists, capable of imparting a desired dumping matrix to a grasped workpiece. Previous work 112. 131 has shown how to select a dumping matrix such that an assembly operatwn can be modc force-guided Thc passive mechanical wrist is to be progmnvnable it can adopt a widc range of damping matrices by virtue of a number of t u d e dampers which inrcrconneet the jo...