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An improved accurate Beam Steering piezoelectric Mechanism for ATlid instrument
19 June 2023
A new tip tilt mechanism based on low voltage piezoelectric actuators has been designed by Cedrat Technologies to answer the high level of stability required for the Earthcare satellite. The Beam Steering Assembly aims to deviate a pulsed high energy UV laser beam to compensate for misalignment between the emission and reception paths of ATLID [1] with a very high stability and resolution. In this paper, the authors points out the BSM development with the main mechanism design issues including performances, mechanical and thermal stability; low power consumption; high integration level; high reliability and safety; cleanliness requirements and give the results of the qualification campaign done at Cedrat Technologies’ to establish the final functional performances in preparation of the Flight Models deliveries for the BSM.
Analysis of Needle–Tissue Friction during Vibration-Assisted Needle Insertion
19 June 2023
In this paper, a vibration-assisted needle insertion technique has been proposed in order to reduce needle–tissue friction. The LuGre friction model was employed as a basis for the current study and the model was extended and analyzed to include the impact of high-frequency vibration on translational friction. Experiments were conducted to evaluate the role of insertion speed as well as vibration frequency on frictional effects. In the experiments conducted, an 18 GA brachytherapy needle was vibrated and inserted into an ex-vivo soft tissue sample using a pair of amplified piezoelectric actuators. Analysis demonstrates that the translational friction can be reduced by introducing a vibratory low-amplitude motion onto a regular insertion profile, which is usually performed at a constant rate.
ATLID Beam Steering Mechanism and derived new piezoelectric based devices for optical applications
19 June 2023
In Space & Defence (as well as in many others fields), there is a trend for miniaturisation in active optics requiring new actuators. Applications also often require the ability to withstand high vibrations and shocks levels, as well as vacuum
compatibility for space applications. A new generation of small and smart actuators such as piezoelectric (piezo) actuators, are resolving this trend, thanks to their capacity to offer high energy density and to support both extreme and various requirements. This paper first presents the BSM mechanism and its requirements, the technologies involved in
the design and the validation campaign results. Secondly, a derived XY piezoelectric positioning stage based on the same APA® and associated Strain Gage sensing technology is presented with its associated performances. Finally, a new piezoelectric motor based on the APA® technology, which allows the combination of long stroke while maintaining high
resolution positioning of optical elements, is presented with experimental performances.
Actionneurs piezoélectriques pour positionnement rapide et précis
19 June 2023
Several classes of low voltage piezo actuators have been developed by CEDRAT TECHNOLOGIES to cover precise positioning needs and / or fast. This paper discusses the ability of these actuators to cover these needs and illustrates this through
various applications (mechanisms, shock absorbers, valves) in the fields of instrumentation, space, aeronautics and automotive.
Active control of vibrations of a space truss using amplified piezoelectric actuators
19 June 2023
The new piezo actuators manufactured by Cedrat Technologies have been developed for the positioning control of space optics but they are spreading widely in various engineering fields such as precise positioning, intelligent control of shapes and generation or control of vibrations. Their ability for the control or active damping of vibrations has been successfully demonstrated at the lab scale in space applications. In a first case, the piezo actuators were used for both for the control of launching vibrations and the positioning control in orbit of a telescope mirror. In a second set of space applications, these piezo actuators have been successfully integrated in a space truss using active tendons for control of micro vibrations, as publicly released at the Industry Space Days (ISD2001, Noordwijk, 9-10 Mai 2001) and as presented in this paper.
Active damping of vibrations applied on ski structures
19 June 2023
Since many years the field of active controls of vibration is growing up and a lot of new applications using smart actuators are developed. In the following study, these concepts are adapted and applied on a general structure of ski to damp the large modes of vibrations keeping the robustness of the control and the static loads during the ride.. Simulations integrating FEM models coupling to electromechanical model were elaborated to obtain the principal performances and to study the stability of the loop.
