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A new amplified piezoelectric actuator for precise positioning and active damping
19 June 2023
Two typical characteristics of direct piezoelectric actuators are displacements of ten micrometers and high stiffnesses. recently, multilayers actuators have been improved, and they now display strains of approximately 1200ppm at low excitation levels (less than two hundred volts). Thus, they are well suited to perform precise positioning of optical devices. But for industrial needs, this performances is still insufficient for positioning devices with larger displacements (in the range of several hundred micrometers).
Cardiolock: an Active Cardiac Stabilizer
19 June 2023
Off-pump Coronary Artery Bypass Grafting (CABG) is still today a technically difficult procedure. In fact, the mechanical stabilizers used to locally suppress the heart excursion have been demonstrated to exhibit significant residual motion. We therefore propose a novel active stabilizer which is able to compensate for this residual motion. The interaction between the heart and a mechanical stabilizer is first assessed in vivo on an animal model. Then, the principle of active stabilization, based on the high speed vision-based control of a compliant mechanism, is presented. In vivo experimental results are given using a prototype which structure is compatible with a minimally invasive approach.
Smart actuators for aircraft applications
4 January 2003
Smart actuators and intelligent structures receive a considerable interest in the fields of Air & Space, to realise new functions or more efficient functions than passive structures. In these fields, there are needs for actuation means offering high mechanical energy density (product of stroke and force divided by the mass), a low power consumption, a resistance to severe environment (such as vibrations) as well as other case by case needs : High resolution (embedded active optics for cameras and telescopes), fast response (active control of structures shape, active damping of vibration)…
A new Rotating Voice Coil Motor for Meteosat Third Generation satellites
19 June 2023
In the frame of the Meteosat Third Generation project (MTG), the future European Operational Geostationary Meteorological Satellites system, Cedrat Technologies has developed a dedicated actuator for the Scan Assembly mechanism (SCA) made by SENER. Such motors are needed to actuate the SCA on the north/south (N/S) and east/west (E/W) axes. The requirement of precise pointing of the SCA induces very specific characteristics for the motorisation. The motor needed characteristics are: to be free from any cogging, high constant motor [N.m/vW] to have a constant torque over full stroke range, to have a very low hysteresis and to have redundant coils. To meet these stringent requirements, the choice was made to develop a specific Rotating Voice Coil Motor.
Rotating step by step piezomotor for nanopositioning and space applications
19 June 2023
Piezomotors are well known in various applications where high precision actuation is required like AFM or handling equipment for semiconductor production. Their specific low speed in direct drive and high torque characteristics combined with high holding torque in off power conditions make them very attractive for any positioning application and especially space mechanisms where low electrical consumption is always sought. A new concept of rotating stepping piezomotor has been developed in the frame of the LISA space project where the mechanism of the telescope orientation was addressed.
Large Stroke Fast Steering Mirror for Space Free-Space Optical communication
2 March 2020
Free-Space Optics and Deep Space Optical Communication request new compact low-power high-stroke high-bandwidth Fast Steering Mirrors. To address this need, CEDRAT TECHNOLOGIES has developed a Magnetically-actuated Fast Steering Mirror called M-FSM, taking heritage of its MICA™ technology. This mechanism offers Rx Ry strokes larger than +/-2° with a 250Hz bandwidth when tilting a 10mm-diameter mirror. Closed loop control is achieved using integrated eddy current sensors. Requested power is reduced leading to low heating and allowing high duty cycle. Vibration tests allow to define first limits and conditions for the M-FSM to bear external vibrations.
