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.
The piloting of APA's composite shell by SA75D power amplifier offers new opportunities for dynamic new applications. Two in particular were received and are being studied: the design of a compact table tensile micro machine for characterizing stress-strain laws at high strain rate of wires, fibers, strands and textile samples that will usefully complete the fleet of dynamic testing machines available, the generation of synthetic jets of air pulsed also studied at ONERA. The energy capacity (displacement, force) without or with an external linear load were modeled versus the rise time using the Simulink code and experimentally measured using a very light device. Other identified improvements remain to be implemented both at the APA's actuators as the Amplifier SA75D to get some gains.
Future matrix sensors will acquire an area on ground and are then susceptible to image shift due to satellite movement during acquisition. Design, Build and Test a breadboard mechanism that could shift telescope line of sight and freeze observed area during image acquisition.
The objective of the European Cleansky project is to develop new technologies for future aircraft enabling a 20-30% fuel burn reduction and related CO2 emissions and a similar reduction in noise levels compared to current aircraft. One of the ways to reach this goal is to improve the aerodynamic performances of current high lift devices. Active flow control is unanimously seen as the best mean to reach this objective. By suppressing flow separation and/or delaying stall, active flow control will increase wing aerodynamic performances. The partnership between CTEC and ONERA in the framework of the VIPER project has led to the design, manufacturing and test of an innovative pulsed jet actuator based on a CTEC amplified piezo-actuator (APA). Its aim is to provide a pulsed sonic jet up to 500Hz with a mass flow around 34 g/s through a slot 1mm wide and 80mm long. Coupled with CTEC SA75D switching power amplifier this actuator produces the expected sonic jet with an electrical consumption around 40W thanks to energy recovery. The results of the actuator characterisation (mechanical, fluidic) are presented in this paper.
This paper presents research and development results of the high performances piezoelectric actuators. Performed studies were concentrated on the improvement of three major parameters: stroke, maximum driving frequency and operational temperature. Two, new actuators were presented and described in this paper. First presented actuator has increased maximum displacement. This actuator has doubled the stroke of standard, long stroke actuators. Improvement of the second actuator was concentrated on increase of constant driving frequency. Finally, special encapsulations designed for both actuators allow using them at high temperatures. Development of these two, new actuators was done simultaneously to the improvement of the electronics. High power amplifier presented in this paper provides sufficient current to drive both actuators at high frequencies.
Many applications require long-term position stability, which relates to the notion of absolute precision over time. Until now, the long-term stability of strain gages (SG) for position measurement was questionable. Using its extensive know-how of strain gages integration and new instrumentation equipment, Cedrat Technologies has managed to demonstrate nanometric position stability of a closed-loop piezo-mechanism with integrated strain gages sensors. This technology opens a wide range of new possibilities for industrial, aeronautical, and space applications.