This paper summarizes a research in the field of active damping space structures. The test facility consists truss structure provided with two elements that can be placed various locations. Each linear piezoelectric actuator collocated force transducer. element is controlled decentralized manner, an integral feedback on voltage applied to piezoactuator. control law always stable and has been found very effective; ratio first mode increased from 0.003 (open loop) 0.09 one actuator.

This paper analyzes in detail the enhancement of piezoelectric stack transducers by means well known 'negative' capacitive shunting. The stability is thoroughly studied: starting from electrical admittance curve transducer, a method introduced that quantifies margins shunted structure. Two different implementations (series vs parallel) are investigated, and lack robustness parallel one demonstrated.

This article focuses on the modeling of structures equipped with Macro Fiber Composite (MFC) transducers. Based uniform field method under plane stress assumption, we derive analytical mixing rules in order to evaluate equivalent properties for d 31 and 33 MFC In particular, are derived longitudinal transverse piezoelectric coefficients MFCs. These validated using finite element computations experimental results available from literature.

This paper describes the results of a six-year project aiming at designing and constructing flapping twin-wing robot size hummingbird ( Colibri in French) capable hovering. Our prototype has total mass 22 g, wing span 21 cm frequency Hz; it is actively stabilized pitch roll by changing camber with mechanism known as twist modulation. The proposed design modulation effectively alters mean lift vector respect to center gravity reorganization airflow. modulated an onboard control board which...

Flapping wing micro air vehicles (MAVs) take inspiration from natural fliers, such as insects and hummingbirds. Existing designs manage to mimic the motion of fliers a certain extent; nevertheless, differences will always exist due completely different building blocks biological man-made systems. The same holds true for design wings themselves, engineering materials differ significantly. This paper presents results experimental optimization shape flexible hummingbird-sized flapping MAV....

Hovering flapping flight is inherently unstable and needs to be stabilized actively. We present a control mechanism that modulates independently the wing amplitude offset by displacing joints of linkage mechanism. demonstrate its performance high speed camera recordings motion as well direct measurements pitch moment lift force. While at 17 Hz prototype produces 90 mN generates moments from −0.7 N.mm 1.1 N.mm. The shows low level cross-coupling in combined roll commands.

This paper considers the active vibration control of cables and cable/structure systems with an tendon controlling axial displacement cable anchor point. It is demonstrated that a force feedback based on collocated sensor measuring tension in feasible this configuration can be associated laws guaranteed stability properties. Experimental results are presented small sag system. They show algorithm provide structure several percent damping parametric resonance does not occur when natural...

Abstract Based on the main features of computer program THGE, paper reviews techniques which are available for construction an accelerogram whose response spectrum matches a design spectrum. First, sample is generated as product stationary random sequence by deterministic shape function. It assumed that spectral properties process have been determined in previous step, order to lead expected maximum responses set single degree freedom oscillators. The principal Fast Fourier Transform used...

This paper extends the classical theory of random fatigue to multiaxial stress fields, using a quadratic criterion. An equivalent uniaxial process is constructed by combining power spectral densities normal and tangential stresses according von Mises process, that we call stress, used evaluate damage with model fatigue. A finite element implementation proposed.

This aricle presents a novel, computer controlled, magneto-rheological (MR) brake actuated, muscular rehabilitation, and evaluation device. The first part discusses various MR architectures compares them. Simple analytical formulae are developed for set of figures merit, which point out the role played by parameters. Based on this analysis, prototype with T-shaped rotor has been designed, built integrated into portable rehabilitation In second article, exercise modes device its control...