Final Report Summary - ESTERA (Multilevel embedded closed-loop control system for fluidic active flow control actuation applied in high-lift and high-speed aircraft operations) 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 design and manufactured by Techdesign (Wroclaw, Poland). Project context and objectives: Implementation of the ESTERA project required a number of analyses and solution of the many technical problems. ESTERA was divided into multiple tasks with their own objectives. All the tasks were included in 6 work packages (WPs). The work plan of project is presented below. WP1: Pre-design analysis and report: CLC system requirements, model and concept Task 1.1: Capturing and analysis of requirements imposed on CLC system (1) Capturing requirements imposed on CLC system such as: (a) technical parameters of sensors; (b) technical parameters of actuators; (c) weight, size and power consumption; (d) integrated modular avionic / distance measuring equipment (IMA / DME) standard adopted and other technical standards (DO-254, DO-160F, DO-178B, MIL-217F, etc.) that have to be fulfilled by CLC system; (e) communication interfaces; (f) wing model; (g) AFC optimisation goals; (h) scope of required wind tunnel tests; (i) location of sensors and actuators; (j) preferences for design, development and validation tools. (2) Analysis of requirements imposed on CLC system: (a) definition of possible constrains and trade-offs in equipment design and development; (b) analysis of changes in wing geometry and possible air flow stream velocity changes associated with pressure sensors and actuators location; (c) initial determination of AFC regulation goals in terms of pressure values that need to be achieved in different working conditions. Task 1.2: Development of CLC system model (1) numerical calculations of air flow pressure changes at the wing surface after introduction of working actuators for different working conditions associated with possible aircraft operations; (2) development of mathematical model of the system under control (actuators coupled with sensors) by description of transmittance (transfer function); (3) analysis and selection of available control techniques (proportional-integral-derivative (PID), linear-quadratic regulator (LQR), predictive, adaptive, hybrid, others) basing on created mathematical model; (4) selection of the best control strategy. Task 1.3: Development of CLC system construction concept (1) Assessment of required CLC system efficiency: - Numerical calculations of air flow pressure changes after introduction of working actuators for different working conditions associated with possible aircraft operations. (2) Review, analysis and selection of available electronic technologies: (a) revision, analysis and ranking of available electronic technologies; (b) revision of communication standards approved by aeronautic industry; (c) technology selection. (3) Definition of main components of CLC system including technologies and standards applied: (a) development of f block diagram of CLC system mock-up; (b) development of block diagram of CLC system prototype; (c) description of communication standards. WP2: CLC system mock-up construction - design and assembly Task 2.1: Development of CLC system construction concept (1) development of CLC system mock-up design in form of technical documentation describing all components, their functionality, technical parameters, communication interfaces, predicted data exchange rates, components interconnection diagram; (2) specification of all measurement equipment and software tools required for wind-tunnel tests. Task 2.2: CLC system mock-up components development and delivery (1) delivery of commercial off-the-shelf (COTS) analogue-to-digital (A / D) converter board required for connection of signals from sensors; (2) delivery of powerful field-programmable gate array (FPGA) board equipped with powerful FPGA circuits; (3) development and delivery of embedded software (VHSIC hardware description language (VHDL) / C++ language) responsible for processing of all CLC system control algorithms; (4) development of specific software applications (testing tool); (5) delivery of cabling system. Task 2.3: CLC system mock-up assembly and integration WP3: CLC system concept testing and optimisation Task 3.1:Preparation of wind tunnel tests model (1) design and production of wing model; (2) installation of wing model, assembly of CLC system sensors and actuators. Check of sensors and actuators functionality and operation correctness. Task 3.2: Initial CLC system testing in wind tunnel (1) Initial tests of CLC system in wind tunnel, confrontation of numerical calculations with measurements, adequate modification of mathematical model, adaptation of CLC system control algorithms (i.e. including se-lection of initial values of control parameters characteristic for specific control techniques). Task 3.3: Main testing - proof of CLC system concept (1) wind tunnel tests of all selected control techniques, gathering and archiving data, CLC system optimisation and efficiency improvement. Multidimensional optimisation of CLC system control algorithms; (2) iterative optimisation of CLC system and selection of the best control parameters specific for selected control techniques. Task 3.4: Final analysis of results of tests performed in wind tunnel and conclusions WP4: CLC system prototype design, production and tests Task 4.1: Design of CLC system prototype (1) Design of CLC system prototype as a multilevel system composed of: electronic units embedded in pressure sensors, electronic units embedded in fluidic actuators responsible for low-level CLC as well as CLC system controller connected with group of sub-controllers and reference sensors responsible for fast synchronisation of sub-controllers matrix system activities. Task 4.2: Production of CLC system prototype Task 4.3: Wind tunnel tests of CLC system prototype (1) naccomplishment of CLC system prototype wind tunnel tests to prove its correct functionality and deterministic behaviour. Task 4.4: Environmental tests of CLC system prototype in IoA laboratory (1) Accomplishment of environmental tests of CLC system prototype required by DO-160 standard including temperature tests, pressure tests, humidity tests and vibration tests. Task 4.5: Final conclusions on the ESTERA project realisation results WP5: Exploitation and dissemination Task 5.1: Development of exploitation plan (1) Description of intellectual property derived from the project realisation, signature of agreements defining and protecting intellectual property rights. Task 5.2: Dissemination of research results (1) preparation and submission of publications; (2) preparation of the ESTERA project graphical material (logo, tem-plates, etc.), dissemination leaflets and presentations; (3) designing, implementation and maintenance of the ESTERA project website. WP6: Management Project results: (1) Aerodynamic concept of the CLC system The CLC system for fluidic AFC was proposed to improve the wing high lift devices performance (especially to delay the flow separation and increase the lift coefficient). The CLC system has been tested experimentally on a two dimensional airfoil model equipped with movable flap. Wind tunnel tests were preceded by numerical calculation. Numerical simulations were conducted to develop a general concept of aerodynamic object being a basis for the proposed CLC system for fluidic AFC. Several different concepts were considered. Finally, the concept described below has been chosen. As a subject of the research, the high-lift wing segment, built based on airfoil NACA0012 and equipped with the 30 % slotted flap, has been used. The flap is deflected usually in take-off and landing flight conditions to increase a lift force of the wing. Description of the CLC system Prototype Introduction to the CLC system - Prototype description A typical CLC system is a control system which uses sensor measurement F of the system output y(t) to compare it to the reference value r(t). The con-troller C then takes the error e (difference between the reference and the output) to change the inputs u to the system under control P. Such system is called a single-input-single-output (SISO) control system; multi-input-multi-output (MIMO) systems, with more than one input / output, are common. In such cases variables are represented through vectors instead of simple scalar values. For some distributed parameter systems the vectors may be infinite-dimensional (typically functions). Every control system must guarantee first the stability of the closed-loop behaviour. Controllability and observability are main issues in the analysis of a system before deciding the best control strategy to be applied, or whether it is even possible to control or stabilise the system. Controllability is related to the possibility of forcing the system into a particular state by using an appropriate control signal. If a state is not controllable, then no signal will ever be able to control the state. If a state is not controllable, but its dynamics are stable, then the state is termed stabilisable. Observability instead is related to the possibility of 'observing', through output measurements, the state of a system. If a state is not observable, the controller will never be able to determine the behaviour of an unobservable state and hence cannot use it to stabilise the system. However, similar to the stabilisability condition above, if a state cannot be observed it might still be detectable. Several different control strategies have been devised in the past years. These vary from extremely general ones (PID controller), to others devoted to very particular classes of systems (especially robotics or aircraft cruise control). A control problem can have several specifications. Stability, of course, is always present: the controller must ensure that the closed-loop system is stable, regardless of the open-loop stability. A poor choice of controller can even worsen the stability of the open-loop system, which must normally be avoided. Another typical specification is the rejection of a step disturbance; including an integrator in the open-loop chain (i.e. directly before the system under control) easily achieves this. Other classes of disturbances need different types of sub-systems to be included. Other 'classical' control theory specifications regard the time response of the closed-loop system: these include the rise time (the time needed by the control system to reach the desired value after a perturbation), peak overshoot (the highest value reached by the response before reaching the desired value) and others (settling time, quarter-decay). Frequency domain specifications are usually related to robustness. Modern performance assessments use some variation of integrated tracking error (IAE, ISA, CQI). For linear systems, this can be obtained by directly placing the poles. Non-linear control systems use specific theories (normally based on Aleksandr Lyapunov's Theory) to ensure stability without regard to the inner dynamics of the system. The possibility to fulfil different specifications varies from the model considered and the control strategy chosen. The PID controller is probably the mostly used feedback control design. PID is referring to the three terms operating on the error signal to produce a control signal. If u(t) is the control signal sent to the system, y(t) is the measured output and r(t) is the desired output, and tracking error e(t) = r(t) - y(t), a PID controller has the general form. The desired closed loop dynamics is obtained by adjusting the three parameters KP, KI and KD, often iteratively by 'tuning' and without specific knowledge of a plant model. Stability can often be ensured using only the proportional term. The integral term permits the rejection of a step disturbance (often a striking specification in process control). The derivative term is used to provide damping or shaping of the response. PID controllers are the most well established class of control systems: however, they cannot be used in several more complicated cases, especially if MIMO systems are considered. CLC system hardware This section contains description of all major parts of the designed hardware plat-form. All major parts of the controller are presented and cover: (a) 4 inputs for pressure sensors (analog or digital interface); (b) 2 outputs for electromagnetic valves: - 2 modes of operation: ON / OFF or pulse-width modulation (PWM), - feedback signal - control output current; (c) CAN interface; (d) universal serial bus (USB) 2.0 diagnostic interface; (e) single supply operation (15 - 36 VDC), typical supply voltage 28 VDC. The block diagram of the CLC system prototype architecture is similar to the mock-up concept that was verified against experience gained during mock-up testing and acquired wind tunnel results. Processor The design is based on CY8C55xx series controller. It is a family of programmable embedded system-on-chip (PSOC) from Cypress. PSOC architecture features: (a) integrated high-precision 20-bit resolution analogue subsystem; (b) programmable PLD-based logic subsystem; (c) 32-bit ARM Cortex - M3 CPU up to 67 MHz; (d) power and clock management subsystems; (e) integrated debug and tracing mechanisms. PSOC is clocked using 24-MHz crystal resonator. Apart from USB link circuitry, an on board programming and debugging connector has been installed which employs MiniProg3 programmer from Cypress. Communication interfaces The module has been equipped with two interfaces: controller area network (CAN) for communication between modules and host computer and USB link which enables data transmission to host computer (dedicated for service and diagnostic). Pressure sensors inputs The circuit is designed for two types of sensors: analog voltage and digital (SPI inter-face) output. For analog sensors voltage output signal is fed to the input of the ADC through the operational amplifier as a buffer and resistive divider. Transil and Zener diode protects the ADC against voltage surges. Digital sensors use SPI interface (common lines master input slave output (MISO) and serial clock (SCLK)). Each sensor has its own signal chip select (CS). There are three sources of power the sensors: (1) 5 VDC from VDDA - dedicated for digital sensors; (2) high precision 3.3 or 5 VDC from reference voltage source; (3) VCCADJ from direct current (DC)-DC converter - when you need a voltage greater than 5 VDC. Electromagnetic valves outputs The module has two solenoid outputs. There are two modes of operation: control the ON / OFF or PWM signal. For this reason, the actuators used are fast MOSFET transistors. Transistors used work well with TTL control signal and require no additional signal forming circuit. A small resistance Rds(on) and high speed switching allow to work this transistors without additional heat sink, Figure 7. Power supplies The circuit is designed to supply the DC voltage range from 15 to 36VDC. The power supply consists of two DC-DC converters and one linear regulator, Figure 8. Provides supply voltages: (a) +12 VDC for operational amplifier and for linear regulator; (b) DC from 5 to 15 V for pressure sensors (optional); (c) +5 V for digital and analog parts, processor and communication circuit. CLC system Embedded software CLC system prototype hardware differs from the mock-up solution significantly and as a result the software designed for the prototype offers much more functionality. The controller can operate in three main modes: (i) idle; (ii) manual control; and (iii) automatic control. Idle mode is dedicated to all measurement and control parameters monitoring and logging. It is intended for system diagnostic and maintenance purposes and does not enable actuator control / activation. Manual control mode is intended for output power stage and actuator circuitry testing and calibration. Automatic control mode is the most important, normal (AFC algorithm based) operation mode. In this mode the system executes selected control algorithm with its parameters established at the set-up stage. Cycle time of the control loop has been established to the value which assures all tasks are fully completed during one cycle. On the other hand, the cycle time should be constant to collect measured parameters and execute algorithm using the same base time period. The software is implemented using PSOC 2.2 Creator IDE provided by Cypress semiconductors, which consists of two parts: (a) graphical design editor where MCU peripherals are configured and connected; (b) C language programming editor for MCU. MCU program is divided into four modules: - ADC manager module - responsible for data acquisition and computing converted ADC values to voltage and pressure. Analog to Digital conversion is triggered by periodic timer interrupt. - Algorithm module - contains group of algorithms that may be used for output control. There are three output control types: (i) regular 8-bit PWM with fixed period set to 768 ms (resolution of about 3 ms) - pulse width depends on value computed by the module; (ii) duty cycle set to 50 % with configurable period (2 - 20 ms) and output counter which kills the PWM block when configured counting value is reached; (iii) bi-state output - sets output to high when computed output value is larger than 0, otherwise sets output to 'low' state; - USB module - connects the controller with PC (ServiceApp), sends voltage / pressure values and computed results to PC and receives and sets parameters defined in ServiceApp. - CAN module - communicates with MCP2515 CAN controller chip via SPI inter-face which is capable of transmitting and receiving data over CAN interface. Functionality of this module is quite similar to the USB module. The following values are sent over CAN interface: pressure, output value, Cp. ServiceApp Service application is an interface that gives an opportunity to configure, gather and present current data received from Estera controller. The programme is written in Python 2.7 language with two additional packages: xwPython (cross platform graphical user interface (GUI) toolkit) and pySerial (serial port encapsulation for Python) consists of two parts which graphically will be presented by tabs. Configuration is the first one that contains several elements gives opportunity to set firmware parameters mentioned in previous chapter. The tab provides two actions read and write which may be triggered using corresponding buttons. The second tab is responsible for data logging. One may choose folder and file name where all received data is stored using .csv format (data values separated by semicolon). The data logging process may be started and stopped by the Start / Stop button. Moreover, all recently received values are presented in the window providing easy data monitoring. USB2CAN USB2CAN firmware may be used to program dedicated controller prepared for this purposes and regular ESTERA controller as well. Main and most important part of this program is to transcode data received from CAN interface (MCP2515 controller chip) and send it to PC over USB. This programme is written for testing purposes. USB2CANApp Usb2CanApp is a standalone application written in C# using MS Visual C# 2010 Express IDE and MS .Net Framework 3.0. Prepared for testing purposes the programme is used to configure and present all data sent by ESTERA controller via CAN interface. This application displays data from up to four ESTERA controllers. Communication with USB2CAN controller is implemented based on drivers and Cypress Suite USB 3.4.7 framework provided by Cypress Semiconductors. Wind tunnel tests of the CLC system prototype Experimental setup and instrumentation The tests were performed in the low speed wind tunnel T-1 (with 1.5 m diameter test section) in the IoA Warsaw for Mach numbers M = 0.1 0.075 and 0.05. The NACA 0012 airfoil segment model of 0.5 m chord, 1 m span and 30 % flap (without optimisation of the gap between flap and airfoil main body) was used. The model was mounted vertically in the test section between two stationary endplates. The airfoil aerodynamic characteristics were determined by measuring pressure distribution on the model surface. Approximately one hundred measurement orifices of 0.5 mm diameter were distributed on the upper and lower surfaces of the airfoil along its chord (on the flap in four cross sections). Based on the obtained pressure distribution the value of aerodynamic characteristics (lift and moment coefficients) were determined. To calculate the total drag coefficient of the airfoil wake rake measurements were taken. All the pressures (from airfoil and rake) were measured by pressure system 'INITIUM' which consists of the three pressure electronic scanners ESP-32HD. The main airfoil section was equipped with the row of the 12 triple nozzles situated in its trailing edge. The nozzles' outlet had a rectangular geometric shape with rounded corners (5.6 mm x 1 mm). They were arranged in a such way that blowing was directed straight into the boundary layer flow on the flap nose. Additional blowing increased the energy in the boundary layer making it more stable and resistant to separation. The flow through the nozzles was controlled by set of the twelve double position electromagnetic valves (MHE4-MS1H type with controlled operating frequency) mounted inside the model. The coefficient of the pressure measured in the point close to flap trailing edge ( as the average of 20 samples) was a parameter defining the state of the flow on the upper flap surface (for the separated flow the pressure value was negative while for attached flow was positive or close to zero). This parameter was analysed by control system which opened or closed the valves. During the tests the total volume flow rate of the blown out air was measured by flow-meter. Wind tunnel tests programme Wind tunnel tests programme of the CLC system prototype assumed to investigate the following issues: (a) influence of the value of pressure coefficient (Cpc) used by the CLC system as a signal for opening or closing the valves on the pressure distribution along the airfoil chord, on the airfoil aerodynamic characteristics and on the air jets volume flow rate; (b) influence of the airfoil NACA 0012 model angle of attack on the pressure distribution along the airfoil chord, on the airfoil aerodynamic characteristics and on the air jets volume flow rate(with using the CLC system); (c) influence of the undisturbed flow velocity on the pressure distribution on the model surface, on the airfoil aerodynamic characteristics and on the air jets volume flow rate (with using the CLC system). All the wind tunnel test were performed with the same sequence of changes in the angle of flap deflection, i.e. initially the flap was deflected from the d = 0 deg up to d = 40 deg with angular speed of 1.4 - 1.5 deg / s, then was kept deflected (d= 40 deg ) for about 20 seconds and finally restored to the starting position (d = 0 deg) with approximately same angular speed. During all these studies CLC system operated and control the opening or closing the valves. With a fully open electromagnetic valves, the proportional valve (contained in air supplying system, Fig.5) was so positioned that total (from 36 nozzles) air volume flow rate was Ù 120 m3 / h (Vj 90 m / s). Wind tunnel test results The wind tunnel result of each run includes one plot which presents the influence of the angle of flap deflection on the total airfoil lift coefficient and also 33 small plots, which present the changes in the pressure distribution on the upper and lower surface of the flap and rear part of the airfoil main body over time (during the CLC system operation at d = 40 deg) . These plots are shown at such order that first presents the moment, when due to CLC system operation, it begins the growth of the negative pressure on the upper flap surface in the area close it leading edge. They end approximately in the same moment including one full cycle of the CLC system operation. These small figures do not present the full airfoil pressure distribution along the chord because the pressure changes in the airfoil front part are insignificant. Environmental tests of CLC system prototype Introduction to the environmental tests This chapter is presenting an approach, test system architecture and results of the tests performed during the realisation of WP4 CLC system Prototype Design, Production and tests. Typical airborne equipment application and specification is described in MOPS. As a result of analysis of equipment application the range and type of environmental tests are established and specified using environmental qualification form. These tests cover over twenty different areas of environmental conditions including temperature, humidity, pressure, vibration, EMC susceptibility and radiation, immunity to volt-age spike and magnetic effect, fire, icing, lightning and many more. Taking on account that the prototype of the CLC system is connected with actuator and sensor systems which are regular off-the-shelf industrial products, the final application conditions cannot be fully specified at this stage. Therefore the scope and the program of the tests is intended to check basic environmental behaviour of the CLC system prototype. In order to perform the environmental tests the prototype has been installed into an industrial grade enclosure and connected with sensors, actuators, power supply and communication link using specialised connectors. Finally, the CLC system prototype was tested according to the procedures covered in the next chapter. The tests were performed between 18 February and 11 March 2013 in environmental testing laboratory located in IOA in Warsaw. Scope of environmental tests of CLC system prototype The CLC system prototype was tested according to the following standard procedures: (a) temperature and Altitude - section 4 of RTCA/DO-160; (b) humidity - section 6 of RTC /DO-160; (c) vibration - section 8 of RTCA/DO-160. Each of the testing procedures were carried out according to the established equipment category. The following information defines equipment categories and corresponding procedure steps as well as parameters of the procedures (temperatures, pressures etc.) according to the sections of the RTCA/DO-160 standard. Temperature and altitude Tests were carried out as for the Category A1 equipment, i.e. equipment intended for installation in a controlled temperature and pressurised location, on an aircraft where pressures are normally no lower than the altitude equivalent of 4 600 m MSL. Humidity Humidity test procedure were performed according to the Category A equipment requirements, i.e. standard humidity environment. This category is defined for equipment intended for installation in civil aircraft, non-civil transport aircraft and other classes, within environmentally controlled compartments of aircraft in which the severe humidity environment is not normally encountered. Vibration Vibration test procedure were carried out as for the Category S equipment, This category is intended to demonstrate that equipment will meet its functional performance requirements in the vibration environment experienced during normal operating conditions of aircraft. CLC system prototype environmental test results Tests of the CLC system prototype were performed according to the sections of the DO-160 specified in section 2 of this document. Tests were carried out according to conditions specified in particular sections of DO-160 using test temperature curves, humidity and pressure values and applying vibration stresses. The controller was operating in all the periods specified in the applicable time slots described in the reference document sections. During the tests all required data were recorded using the data logging station. Further analysis of the recorded data proved that controller functionality encompassing switching outputs, input signals measurements and communication data ex-change operated properly during the whole test period. Conclusions In the project ESTERA complete CLC system for fluidic AFC actuation at the wings trailing edge was designed and manufactured together with the necessary controller unit. The CLC system prototype has been tested experimentally on a two dimensional airfoil model NACA 0012 equipped with movable flap. During the tests the coefficient of the pressure measured in the point close to flap trailing edge was a parameter defining the state of the flow on the upper flap surface. This parameter was analysed by control system which opened or closed the valves. The tests were performed in the low speed wind tunnel T-1 (with 1.5 m diameter test section) in the IOA, Warsaw for Mach numbers M = 0.1 0.075 and 0.05. Wind tunnel tests were preceded by numerical calculation. Performed wind tunnel tests of the CLC system prototype have fully confirmed the correctness of the assumptions made for the model design as well as the correctness of its manufacturing. Tests showed the following: - Blowing is an effective way to increase the lift coefficient achieved by the airfoil with strongly deflected slotted flap - the increase was maximally 30% of the lift coefficient without blowing. The lift increases not only due to reduction a separation zone on the flap but also due to increasing a negative pressure on the upper surface of the main airfoil. - The tests confirmed hypothesis that the measurement of the pressure on upper-aft part of the flap (in one point only) allows on detecting the separation. - The investigation confirmed an efficiency of the CLC system as a way to increase lift with relatively low volume flow rate of the compressed air. Using a pulsed jets controlled by CLC system the volume flow rate was diminished from Ù 120 m3/h (steady blowing) to Ù 68 m3 / h (for Cpc = 0.0 ) and to Ù 33 m3 / h (for Cpc = -0.4). - The increase in airfoil CL value due to CLC system operation was generally independent of the value of pressure coefficient used by the CLC system as a signal for opening or closing the valves i.e. Cpc. - Duration of the one complete cycle of the CLC system operation was about dt 65 ms. Since the opening of the valves to the full flow attachment on the flap passes about 12 / 14 ms. On the other hand since the closing of the valves to the full flow separation on the flap passes about 27 / 28 ms. - During the flap deflection (the increase of the flap deflection from d = 0 to d = 40 deg and decreasing from d = 40 to d = 0 was tested) the angle of attack significantly affects the beginning and end of the CLC system operation. The increase in the airfoil angle of attack delays the start of the CLC system operation. - The change of the undisturbed flow velocity (in the range M = 0.05 / 0.1) does not really effect on the qualitative changes in the flow around airfoil flap associated with the CLC system operation (the changes are quantitative and only in the aerodynamic characteristic values). The decrease of the undisturbed flow velocity results in the decrease of the pressure coefficient in the nose part of the flap This decrease of the pressure coefficient is caused by a higher ratio of the air jet velocity to undisturbed flow velocity. The environmental tests of the CLC system prototype was performed in IoA Environmental Laboratory according to the standard procedures (temperature, altitude, humidity and vibration). The environmental tests (curried out according to RTCA/DO-160 document) and within the scope specified in Section 2 of this document show that CLC system prototype passed the test procedures. Potential impact: (1) reduction of air transport costs; (2) reduction of environmental pollutions related to aircrafts exploitation by lowering of fuel usage; (3) fostering cooperation between SMEs and large aviation industry players leading to proven subcontracting models; (4) building confidence based on real task / project execution among research centres, SMEs and large companies; (5) popularisation of air transport as economic and safe way of travelling and transportation. Exploitation plan for ESTERA - project results Description of intellectual property In accordance with the grant agreement signed by ESTERA Consortium all intellectual property created during project realisation belongs to the Partner that has created each particular portion of IP. In case the IP is a result of common work of the partners it should be managed and exploited according to Section II.26 of the Grant Agreement. Regulations related to intellectual property management are also included in the implementation agreement however, it follows rules described in the grant agreement mentioned above. Apart from these two documents the consortium did not create any other agreements governing intellectual property rights of Partners. Intellectual Property created during ESTERA project realisation by the project participants (IOA, TECHD): - Trailing-Edge Triple Mini-Nozzle - Triple Mini-Nozzles (TMN), located at the trailing edge of the main wing, are used to control the flow on the single-slotted flap, particularly to prevent the flow on the flap against a strong separation. This shape was optimised taking into account requirements of: (a) minimisation of pressure losses in the nozzle ducts; (b) uniform distribution of mass flow rate along the span of TMN, through all three outlets. - Pressure coefficient as a CLC system parameter - the concept that coefficient of the pressure measured in the point close to flap trailing edge was a parameter defining the state of the flow on the upper flap surface (for the separated flow the pressure value was negative while for attached flow was positive or close to zero). This parameter was analysed by control system which opens or closes the valves (IOA). - Control algorithm of CLC system - although the control strategy is typical, there are important factors and optimisation techniques developed during wind tunnel tests which ended up with control algorithm that is effective and constitutes significant IP in a form of know-how (Techdesign). - CLC system control hardware - design and further tests of the controller proved that the hardware platform is highly integrated and versatile control engine, suitable for tasks in demanding conditions and can be applied in the whole range of control systems (Techdesign). The project consortium proposed to protect Intellectual Property generated during ESTERA project realisation by patent (where possible and economically justifiable). Proposed patent claim refers to CLC system of blowing on wing flap. CLC system can be a subject to further research and development works with industrial and academic partners from aeronautic industry. Analysis of the market potential Aviation industry is expanding rapidly and potential demand for AFC solutions shall grow accordingly. Although needs concerning new aircraft orders fluctuate with varying gross domestic product (GDP) growth and differ geographically, most of the market forecasts estimate annual rate of fleet growth for at least 2 %. The number may look moderate but apart from new deliveries, this process will also involve constant exchange of existing fleet. Costs of CLC System production currently may be estimated at the level of EUR 1 500 and it includes: (a) costs of materials; (b) costs of CLC system manufacturing and start-up; (c) cost of system testing and qualification processes. The above estimation cannot be precise at this stage and shall be verified further if potential users shall be interested in industrialisation. There are numerous customers that can be potentially interested in CLC systems. Certainly, natural and most important group of customers / users of the system are members of smart fixed wing aircraft (SFWA) consortium. Preparation to industrialisation As a research and development (R&D) performing SME, Techdesign is definitely interested in further industrialisation of CLC system controller. Discussions concerning possible development actions of current prototype have been started with the topic manager. These actions should be focused on controller ability to drive other types of actuators than tested and applicability for functional tests to be performed in real aircraft conditions. Conclusions In general, the results of the ESTERA project are promising. Achieved improvement of lift coefficient is substantial and the AFC solution employed in the project is a good base for further development. It takes common efforts of IOA, Techdesign and SFWA consortium members to exploit fully the results and experience gained during project execution. Directions of next possible activities were highlighted during meetings of project partners and SFWA topic manager but any decisions in this area should be based on final project evaluation. Dissemination of ESTERA project research results Publications and conferences There are several scientific papers, presentations and other documents created during ESTERA project realisation. Some of them were presented at conferences and other events organised within the time cycle of the project, some others are in preparation for presentation during upcoming conferences and meetings. List of conferences where ESTERA project results was presented: (1) 'XV Mechanics in Aeronautics' 28 - 31 May 2012, Kazimierz Dolny, Poland - PhD Andrzej Krzysiak - 'Design of the Flow Control on the Wing Flap Working in the Closed Loop Control System'. (2) '52 Symposium Modeling in Mechanics' 23 - 27 February 2013, Ustron, Poland - PhD Andrzej Krzysiak - 'Flow Control on the Wing Flap Working in the Closed Loop Control System'. - MS Pawel Ruchala 'Autonomic System of the Detection and Preventing of Flow Separation on the Airfoil Equipped with Flap'. List of conferences where ESTERA project results shall be presented: (1) 'CEAS 2013' 16 - 19 September 2013, Linköping, Sweden - PhD Andrzej Krzysiak - 'An Experimental Study of a Separation Control on the Wing Flap Controlled By Close Loop System' - PhD Wienczyslaw Stalewski - 'Computational Design and Investigations of Closed-Loop, AFC Systems Based on Fluidic Devices, Improving a Performance of Wing High-Lift Systems. Published technical papers: - PhD Andrzej Krzysiak - 'Design of the Flow Control on the Wing Flap Working in the Closed Loop Control System' , Mechanics in Aeronautics ML-XV, pp. 149-158, Warsaw 2012. Dissemination materials For dissemination purposes a set of PowerPoint presentations has been prepared. Partner websites were supplemented by the information and further links describing ESTERA project. List of websites: http://www.ilot.edu.pl/estera Contact details: Andrzej Krzysiak IOA Al. Krakowska 110/114 02-256 Warsaw Poland Email: andrzej.krzysiak@ilot.edu Tel: +48-228-46 0011 ext. 363, Fax: +48-228-685107 Related documents Final Report - ESTERA (Multilevel embedded closed-loop control system for fluidic active flow control actuation applied in high-lift and high-speed aircraft operations)
