Actuators for aeronautical applications
- Written by Paul Sente
Electromechanical converters engineering has evolved continuously during the last decades due to availability of :
• new materials, notably rare-earth magnets for affordable prices;
• more and more performing software tools for field calculation and optimization.
The activities in this domain concern essentially the design of high performances actuators for a wide range of areas : going from aerospace (in cooperation with industrial partners working in the field) to robotics and medical applications.
For the aeronautic industry, for example, a study has been recently carried out for estimating the possibility to install electric generators in a civil aircraft engine nacelle. Other studies, conducted in the field of European projects, concernes the the design and the control of electrical actuators used in thrust vector control, direct drive servovalves, steering systems.
It is clear that power electronic converters play an important role in such mechatronic systems as they act as interface between the control, an electrical energy source and the controlled mechatronic system. But this is the subject of another theme among our research projects.
European Union : DRESS Project
Design, modelling and control of an electromechanical steering system for a nose landing gear (in cooperation with SAAB Avitronics) :
The goal of this project is to research, develop and validate a distributed and redundant electrical steering system technology for an aircraft nose landing gear, that will provide improved competitiveness and improved aircraft safety by:
- reduced system weight at the aircraft level, replacing the current hydraulic actuation by electrical actuation.
- improved aircraft safety provided by the higher reliability, the higher levels of safety objectives with associated redundancies that will be imposed to the new system, beyond the current technology capabilities.
- subsequent ability of the steering system, with its improvements on safety, to be integrated in a future fully automated aircraft ground guidance system providing the aircraft with a true all-weather (true zero visibility) capability, hence offering significant aircraft operation gains and enabling a more efficient Air Transport System. The current steering system is the weak link of the ground guidance system.
DRESS is composed of four technology research work-packages (WP), two prototype manufacture and evaluation testing work-packages and one management work-package :
- Specifications and assessment criteria
- Research on optimised system architecture
- Electro-mechanical technologies research <= our group
- Components manufacture
- Technology Integration
- Technology evaluation
DRESS will achieve this technology breakthrough, investigating in both fields of system architecture and electro-mechanical actuation, by bringing together 13 actors of the European aeronautics industry including an aircraft manufacturer (Airbus UK), a landing gear manufacturer (Messier-Dowty), two Systems and Equipment manufacturers (SAAB, Messier-Bugatti), a Research Institute (IA), five universities (INSA, UHA, UCL, UCV, BUTE), and three SMEs (TTTech, EAT, SPAB) with their own specific expertise. DRESS is a 3-year STREP led by Messier-Bugatti with an overall budget of 4M.
Our team is in charge of the work package WP430 : "Modelling and thermal analysis" within the WP400 (upper level) group : Electro-mechanical technologies.
Description of our work package
- Modelling of motor and associated electronics (UCv in cooperation with UCL)
- Functional simulation models for motor, power electronics and motor torque and/or speed control
- Modelling, simulation and evaluation of different motor, motor control electronics architectures ( simple, dual, active-active, active-standby). Especially evaluation of SPAB patents,/ patent pending regarding control electronics redundancy architectures. Simulation and analysis of electrical failure modes and failure modes effects.
- Simulations of solutions identified in WP 420 (“Electric motor / power card technology study”).
- Inclusion of thermal models.
- Interface with the control laws issued by WP320 ("System control laws").
- Interface for inclusion in the lumped parameters virtual prototype of the actuator developed by INSA in WP 410 (“Actuator architectures studies and sizing”).
- Thermal Analysis of Motor and associated electronics (UCL in cooperation with UCv)
- Analysis and calculation of the thermal properties of the selected designs (motor magnetic and ohmic losses, power electronics losses), thermal flow between heat sources (motor/electronics) and heat sinks (mechanical structure).
- Survey and analysis of potential use of new high temperature semiconductors
- Study of power electronics thermal and electrical stress as a function of duty cycle
Francis Labrique (WP430 Task Leader), Vincent Defosse, Sergiu Ivanov (UCv), Ernest Matagne, Paul Sente.
European Union : Elac, EPICA, ELISA and POA Projects
Modelling and control of electromechanical (EMA) and electro hydraulic actuators (EHA) for flight surface control (past projects; in cooperation with S.A.B.C.A.)
Conventional aircraft architectures comprise a combination of systems dependent on mechanical, hydraulic, pneumatic and electrical sources. These systems do not typically consume or distribute power efficiently, a problem that grows more acute with rising on-board operational and passenger demands for electrical energy.
The POA (Power Optimised Aircraft) project is looking for novel ways of generating, distributing, and using onboard aircraft power. Its ultimate goal is to achieve a ‘more electrical aircraft’ that better distributes power and uses it only when needed.
The optimised, full electric aircraft architecture would eliminate the need for a mechanical gearbox, while equipment such as the cabin air conditioning system and the flight controls would use more electrical power.
(extracts from European Commission pages on Research & innovation - Transport)
Contracts with S.A.B.C.A.
Electromechanical actuators for thrust vector control (Vega and Ariane launchers)
In many areas, particularly in regard to critical functions in space and aviation applications, reliability is a major constraint. To achieve the required level, a double or triple redundancy devices will often be choosen, which increases the size and cost.
A less restrictive way to meet the safety requirements is to design fault-tolerant converters, in that they could still provide a functioning, albeit with reduced performance, even after a power converter or its associated electronics.
This will achieve the required level of reliability while reducing the level of redundancy and service constraints.
The research presently done in cooperation with SA.B.C.A. deals with the design of such actuators: high performance and fault tolerant.
Power and control electronics
Power and control electronics for Direct Drive servo-Valves powered by a piezo-electric motor
This subject is handled in the "Power Electronics" section of the research projects.