Cedrat Technologies, innovation in mechatronics

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.

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.

Implementation of 3D capabilities on ultrasonic imaging systems tantalizingly proves the high interest for this diagnosing modality. However, to become a clinical tool, 3D ultrasound has to spend further technological efforts in acquisition performance and probe size to deliver on the fly, quality volumetric images as well as current functionalities.

Existing piezo motors such as travelling wave motors present several technical limitations, they are not useable for linear drive, they cannot be easily adapted to specific rotational needs and the development of customised solution is expensive. The proposed Ultrasonic Piezo Drive (UPD) aims at overcoming these limitations. It is a shell-based stator using multilayered piezoceramics in d33 mode. Excited at only 1-10V, it produces an ultrasonic elliptical vibration large enough to direct drive any type of second body by friction. Tangential driving properties of UPD20 are typically in the range of 100-200mm/s max speed and 15-30N max force.

After the development of switching amplifier SA75 for piezoelectric actuator driving, CEDRAT RECHERCHE has developed linear amplifiers. The LA75 electronics are presented in the form of a 19" rack, and are proposed into various version.

The method of fault positions has been used to study the post-fault voltage sags in the supply to a large chemical industry. the main concern are fault in the on-site distribution systems.

We are delighted in announcing the successful test of our LPM20 linear piezoelectric motor, carried out in June this year at the CNES (French Agency Space), Toulouse in vacuum conditions.Developed for positioning applications, the piezoelectric motor has proved to be a very interesting solution thanks to its high massive force, its zero consumption at rest and its high precision. For space applications, it is a question of obtaining an identical behaviour in ambient and in vacuum conditions. However, the friction drive that is the key to the functioning of the piezoelectric motor, limits the lifespan and poses tribology problems.