Publications

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.

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.

Aero India 2003 Piezo actuators air & space

19 June 2023

Several classes of Piezo Actuators based on low voltages piezo ceramics have been developed by CEDRAT TECHNOLOGIES in order to cover needs for long stroke, precise and/or fast positioning in the fields of air & space applications. A specific class of Amplified Piezo Actuators, so called APA has been patented, developed and qualified. Their applications concern subjects as various as Scientific Instruments for Space payloads (Telescopes, Microscopes), Micro-Satellites Propulsion Valves or Active flaps of Helicopter Blades.