Overview
ESTERA project objective was to develop and deliver prototype of Closed-Loop Control System optimized for Active Flow Control actuation applied at the wing’s trailing edge or wing’s body and used for drag reduction / buffeting control in high-lift and high-speed aircraft operations. The project objective was achieved by:
- acquiring requirements imposed on CLC-System (particularly in terms of working conditions, wing geometry and sensors / actuators location);
- numerical simulations of air flow speed and pressure at wing surface (without and with working actuators) to define regulation goals (pressure values that shall be achieved) and to select the best control strategy;
- building system-under-control mathematical model;
- selection of control techniques to be tested (PID, LQR, adaptive, hybrid, others);
- definition of test cases and scope of tests;
- construction CLC-System Mock-up from already available parts;
- testing of selected control techniques on wing model in wind tunnel provided by Consortium and their iterative improvement / efficiency optimization due to test results with support of MATLAB tool (applying stochastic and evolutionary algorithms);
- finally production and delivery of CLC-System prototype to SFWA.
Multi–level distributed CLC-System was proposed, constructed of signal conditioning units embedded in sensors, sub-controllers embedded in actuators and main controller, connected in digital communication network (e.g. ARINC 429). This construction improved CLC-System efficiency by separation of tasks performed at high and low level as well as improve CLC-System reliability by independency of local sub-controllers. CLC-System Prototype was miniaturised using FPGA/CPLD technologies to be embedded in AFC actuators and sensors. CLC-System prototype was designed, developed, documented and tested (EMC & climatic tests) according to required standards (DO-160F, DO-178B, DO-254, EMC, etc.) to ensure possibility of obtainment of EASA certificate.
Funding
Results
Executive summary:
The ESTERA project covers issues related to flow control. The objective of this project was to develop, test and deliver prototype of closed-loop control (CLC) system optimised for active flow control (AFC) actuation. This CLC system was designed to be applied at the wing trailing edge and used for aerodynamic characteristics improvement (drag reduction, lift enhance) in high-lift aircraft operations. The project objective was achieved by constructing and experimental examination of the CLC system of blowing an air on the upper flap surface during its deflection and retraction.
Numerical simulations were conducted to develop a general aerodynamic concept of the proposed CLC system for fluidic AFC. Several different concepts were considered. Finally, as a subject of the research, the high-lift wing segment, based on airfoil NACA0012 with the 30 % slotted flap and equipped with air blowing system situated at the airfoil main body trailing edge, has been chosen. In proposed, developed and tested CLC system as a fluidic actuators the electromagnetic valves were applied and a pressure on flap trailing edge as a control parameter was used.
The numerical simulation as well as experimental test of the proposed CLC system for fluidic AFC were performed in IOA (Wasaw, Poland) while control unit (hardware and software) was designed and manufactured by Techdesign (Wroclaw, Poland).