Cedrat Technologies, innovation in mechatronics

High Power Synthetic Jet Actuator (SJA) based on compact piezoelectric actuators, have been developed and tested by CEDRAT TECHNOLOGIES (CTEC) and ONERA, under French National funding RAPID from DGA. This publication presents the modelling approach with early breadboarding results, the final design chosen for integration onto an aircraft airfoil mock-up, the performance test results on the SJA device prior integration, and the final aerodynamic performance test demonstration achieved at ONERA wind tunnel test facility.

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.

ABC is the acronym for ‘’Active Blade Concept’’ and represents a 38% Mach scaled model rotor of the Advanced Technology Rotor (ATR) of Eurocopter Germany (ECD, [4]). In contrast to the ATR the model rotor is fully articulated. Specifically, it is equipped with a flap at the trailing edge of each blade, which is driven by a piezoelectric actuator. The ABC project is a cooperation between the French ONERA and the German DLR within the research concept ‘’The Active Rotor’’.

Actuators are key elements of air- and spacecrafts. In the recent years the concept of the more-electric aircraft pushed the development of electrical actuation systems to substitute hitherto used hydraulic actuators in a broad range of applications such as flight control, landing gear and brake actuation.

Smart actuators and intelligent structures receive a considerable interest in the fields of Air & Space, to realise new functions or more efficient functions than passive structures. In these fields, there are needs for actuation means offering high mechanical energy density (product of stroke and force divided by the mass), a low power consumption, a resistance to severe environment (such as vibrations) as well as other case by case needs : High resolution (embedded active optics for cameras and telescopes), fast response (active control of structures shape, active damping of vibration)…