Cedrat Technologies, innovation in mechatronics

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.

Amplified Piezo Actuators (APA®) from CEDRAT TECHNOLOGIES are known to be compact and especially performing in dynamic applications. The recent evolutions realized on the APA® and drive electronics allow them to address active damping better than magnetic proof mass in terms of the Force to Volume ratio above some 10Hz. The dynamic capability of the APA® has been improved thanks to preload method enhancement. Research has successfully shown the possibility to achieve a high dynamic force level similar to the static blocked force of the piezo actuator. This technical progress coupled with an amplified motion makes possible the generation of high mechanical proof mass load at relatively low frequency. It produces a force higher than 100N in a volume of Ø40x75mm within a range of [100-300Hz]. This paper presents relevant uses of APA® for active damping in machining applications. Several machining case studies are reported integrating Amplified Piezo Actuators within the spindle head, inside the cutting tool or beside the workpiece clamp.

The MICATM linear actuator family (Moving Iron Controllable Actuator) is being continuously improved at CEDRAT TECHNOLOGIES (CTEC) for applications needing high controllable stroke, force, and power. The MICA300CM is a new actuator model, having improved configuration based on cylindrical shape. A first version based on plain bearing offers up to 12mm stroke and 300N continuous force with a weigh of only 3kg. A second version is based on new frictionless flexure bearings. The former one is especially designed to achieve zero maintenance over several years of operation, with high efficiency, infinite resolution, and high controllability performance. This version of the MICA300CM has been derived to offer a proof mass configuration, for vibrationcancellation applications on machining processes. A latest version is also currently under design, and prototyping, specifically for reciprocating power piston applications, such as compressors, pressure wave generators, and pumps. Its high efficiency, ultra-long lifetime capability, and compactness, makes it perfectly suitable for embedded thermal machines based on Stirling, Joules Thomson, and Rankin Thermodynamic cycles. This paper presents this 4 design concepts, their test results and perspective for applications.

A project called RPA (Rotor à Pales Actives) was launched three years ago to study the possible benefits of implementing active trailing edge flaps on a helicopter main rotor. The main objectives of this project are to decrease BVI noise in descent flight and improve the dynamic behavior of the rotor throughout the largest possible flight domain. After a first phase dedicated to the design of the best flap configuration at scale 1, the second phase of the project deals with the design of a wind-tunnel scale model of a rotor equipped with active flaps. An off-the-shelf piezo-electric actuator is used together with a specific patented flap-driving mechanism. Such an active device was tested under centrifugal loads as well as under aerodynamic loads in order to prepare future wind-tunnel tests. The results obtained under centrifugal loads allowed to clear the active device but the aerodynamic testing showed that some improvements were needed. Corresponding modifications are under way to fully clear the active device to be used on a complete rotor model.

Fast growing Laser and new optic applications drive more and more needs for beam steering mirrors (BSM) and Fast Steering Mirror (FSM). For space optic instruments, CEDRAT TECHNOLOGIES has developed for 20 years several piezoelectric tip-tilt mechanisms. Presented recent examples include the ATLID BSA small tit tilt for quasi static nano pointing and MEFISTO, a large tit tilt for fast micro positioning. These space mechanisms perform high precision functions while being compact, lightweight and resistant to external vibrations and shocks. As shown in the paper, these advantages allow these technologies addressing several needs for other optronic applications than space, such as active stabilisation, micro scanning, disturbance compensation in IR imagers or telescopes.