Cedrat Technologies, innovation in mechatronics

In Inertia Drive Motors, generated motion is based on stick-slip principle. Current analytical models are predictive enough to calculate qualitatively their optimal performances, such as maximal step size and speed, with relatively few input parameters. Butn they do not take into account the contact life and temporal evolution of parameters as friction factor all along lifetime of IDM. So analytical models reach their limitswhen precise predictions are necessary.

To introduce in vivo multifrequency single‐shot magnetic resonance elastography for full‐FOV stiffness mapping of the mouse brain and to compare in vivo stiffness of neural tissues with different white‐to‐gray matter ratios. Brain mechanical properties influence many vital neurological functions including brain development, metabolism, and tissue repair. However, studying brain mechanical properties in a noninvasive fashion encounters a number of challenges including the fact that the brain is protected by the skull as well as the heterogeneous and complex geometry of the brain. At present, magnetic resonance elastography (MRE) is the sole modality allowing noninvasive measurement of in vivo brain mechanical properties in patients and small animals.

In many cases piezoelectric actuators reach limitations in terms of maximum displacement and cycling frequency. Most amplified actuator technologies struggle to go over the millimeter of stroke. Furthermore certain closed-loop applications demand stroke measurement integrated into the actuator. While few amplifiers on the market can offer 20Amps current over a few 100ms, development of high power supply units runs parallel with actuator improvements. However with the introduction of high power supplies comes the problem of self-heating of the piezo ceramic. Finally extreme environmental conditions in terms of harsh conditions and high temperatures need to be addressed in order to open these markets for piezo actuators. Cedrat Technologies has been heavily investigating in solutions to overcome all of these drawbacks and these solutions are presented here.

Synchrotrons need robust products. That’s why the association of piezo actuator technology and CEDRAT TECHNOLOGIES (CTEC) know-how has been successful for synchrotron mechanisms projects. The technological brick is the “Amplified Piezo Actuator” (APA®) tested and widely used in space applications, it is often implemented in CTEC piezo mechanisms and provides a high level of robustness. Modifying the layout and the number of APA® allows several needs to be addressed within beamlines. Three applications developed in collaboration with the EMBL, PAL and SOLEIL will be presented in this paper. The first application consists of cutting a beam with a piezo shutter. The maximum beam diameter is 3 mm. The second mechanism allows the energy of a beam to be modified by using a series of piezo actuated filters. And the last mechanism aims at modifying the beam section shape with an active piezo micro-slits mechanism.

Many applications and more specifically space projects would have use of a stable sub-micrometre positioning actuator. In order to meet this need, Cedrat Technologies has designed the new FSPA brand. This linear stepping actuator offers sub-micrometric positioning resolution along 5mm stroke combined with high actuation force (>100N) and the ability to hold its position without power. Starting from the FSPA, a special version is being developed for the IASI-NG space instrument. This light (500g), fully redundant actuator is designed to achieve 150μm stroke with locking at rest, 60 N force with a 25-50 nm step resolution and resistance to launching. The paper presents the base FSPA actuator and the new high performance space variant.

Modular Stepping Piezo Actuators (MSPA) use the stick-slip principle to combine high resolution positioning (<μm) with long stroke (>cm). These motors provide unlimited motion in both rotation and translation. Fine mode allows precise positioning (<10nm). Since it is a module, it easily fits any existing devices requiring up to 25N of driving force with a speed up to 50mm/s. This motor module benefits the use of space qualified Amplified Piezo Actuators (APA®). It is then deemed a good candidate for severe environments such as vacuum, cryo, vibrations, nonmagnetic etc… This paper presents three technical challenges encountered for the development of MSPA product. The first one is the issue of noise resulting from stick-slip actuation below ultrasonic frequencies. The second is the miniaturization at low voltage: One is macro size (sugar cube) working at 45V is characterized, the other is micro size (grain of rice) powered at low voltage below 60V. The third challenge is the successful and reliable integration of the module within new customer applications and new Cedrat Technologies’ products.

In the framework of a French National Program, the project ASPIC aims at using synthetic jet actuators to improve aerodynamic performance of aircrafts. The partnership between Cedrat Technologies (CTEC) and the French Aerospace Lab (ONERA) in this project has led to design, manufacture and test a high efficiency innovative synthetic jet actuator. This device relying in part on an ONERA patent is actuated by a CTEC amplified piezoactuator (APA). Its aim is to provide a high speed synthetic jet compatible with flow control application on aircrafts or any other vehicle. Latest available test results and experimental performances of the ASPIC synthetic actuator are presented in this document: in particular, a peak exit velocity of 135m.s-1 during suction, and of 150m.s-1 during blowing, with an optimal actuation frequency bandwidth between 200 and 300Hz.