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Actuators in adaptronics: piezoelectric actuators
19 June 2023
Piezoelectric actuators have increased their number of application in adaptronics over the past decade [1]. They can be used with several drive and control strategies and they are more adapted to mechatronics applications requiring bandwidth, accuracy and/or lightweightness. The purpose of this paper is to recall the different existing piezo actuators, the different drive and control techniques and finally review several applications in machine tools, optics.
Actuators, transducers and motors based on giant magnetostrictive materials
19 June 2023
Rare earth-iron magnetostrictive alloys, especially Terfenol-D, feature “giant” magnetostrains: static strains of 1000-2000 ppm and dynamic strains of 3500 ppm are reported.
Advantages of large piezo actuators and high power drivers for fatigue and fretting test
19 June 2023
Constant expansion of new materials requires fretting or fatigue machines in order to test their failure. In many cases tests must be performed in severe conditions and at high frequency. These requirements come from the use of the materials in highly demanding applications. At the same time it is expected to reduce the time required to characterise such materials. Piezoelectric actuators are more and more common in testing machines, but they still reach limitations in terms of maximum displacement, cycling frequency or power. In order to cope with these issues, Cedrat Technologies has been investigating solutions. In this paper long stroke and high frequency actuators, coupled with powerful driving control are introduced. These actuators are based on piezoelectric materials and can be easily integrated into the fatigue machines. In order to improve precision of these tests, two of the most common displacement sensors used in smart actuators are also presented in this paper.
A bistable piezoelectric harvester for wideband mechanical frequency excitation
19 June 2023
The developments of autonomous systems such as for self health monitoring, embedded systems are increasingly used in industrial applications. The energy supply is a key point for the development of such systems. Solutions based on battery have limited life time and the power supplies through wires aren’t always appropriate and easy to install. Furthermore, the battery recycling is complex and an expensive process. The researches on power supply through harvesting systems are increasing in the same way the autonomous systems.
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).
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.
