Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G5/00—Traffic control systems for aircraft, e.g. air-traffic control [ATC]
  • G08G5/0004—Transmission of traffic-related information to or from an aircraft
  • G08G5/0013—Transmission of traffic-related information to or from an aircraft with a ground station
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T7/00—Brake-action initiating means
  • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
  • B60T7/16—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger operated by remote control, i.e. initiating means not mounted on vehicle
  • B60T7/18—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger operated by remote control, i.e. initiating means not mounted on vehicle operated by wayside apparatus
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/17—Using electrical or electronic regulation means to control braking
  • B60T8/1701—Braking or traction control means specially adapted for particular types of vehicles
  • B60T8/1703—Braking or traction control means specially adapted for particular types of vehicles for aircrafts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/17—Using electrical or electronic regulation means to control braking
  • B60T8/172—Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
  • B60T8/321—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration deceleration
  • B60T8/325—Systems specially adapted for aircraft
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64F—GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
  • B64F1/00—Ground or aircraft-carrier-deck installations
  • B64F1/36—Other airport installations
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G5/00—Traffic control systems for aircraft, e.g. air-traffic control [ATC]
  • G08G5/0017—Arrangements for implementing traffic-related aircraft activities, e.g. arrangements for generating, displaying, acquiring or managing traffic information
  • G08G5/0021—Arrangements for implementing traffic-related aircraft activities, e.g. arrangements for generating, displaying, acquiring or managing traffic information located in the aircraft
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G5/00—Traffic control systems for aircraft, e.g. air-traffic control [ATC]
  • G08G5/0017—Arrangements for implementing traffic-related aircraft activities, e.g. arrangements for generating, displaying, acquiring or managing traffic information
  • G08G5/0026—Arrangements for implementing traffic-related aircraft activities, e.g. arrangements for generating, displaying, acquiring or managing traffic information located on the ground
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G5/00—Traffic control systems for aircraft, e.g. air-traffic control [ATC]
  • G08G5/0073—Surveillance aids
  • G08G5/0091—Surveillance aids for monitoring atmospheric conditions
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G5/00—Traffic control systems for aircraft, e.g. air-traffic control [ATC]
  • G08G5/02—Automatic approach or landing aids, i.e. systems in which flight data of incoming planes are processed to provide landing data
  • G08G5/025—Navigation or guidance aids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T2210/00—Detection or estimation of road or environment conditions; Detection or estimation of road shapes
  • B60T2210/10—Detection or estimation of road conditions
  • B60T2210/12—Friction
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C25/00—Alighting gear
  • B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface 
  • B64C25/42—Arrangement or adaptation of brakes
  • B64C25/426—Braking devices providing an automatic sequence of braking
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06N—COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
  • G06N20/00—Machine learning

Definitions

• TITLE Method and system for determining the coefficient of friction of an airplane on a landing strip
• the present invention relates, in general, to the optimization of airport traffic and the reduction in the number of runway closures which can have very significant financial consequences for airport operators.
• the invention relates to the determination of the conditions of the landing strips of an airport in order to optimize the use of the strips, while satisfying the safety requirements.
• the object of the invention is therefore to overcome these drawbacks and to provide a state of the conditions of landing strips for aircraft which is of increased reliability and relevance and which can be used for the optimization of the use of runways by airport operators.
• the subject of the invention is therefore a method for determining a coefficient of friction of an aircraft on a landing strip which comprises the steps of:
• the data used to determine the landing runway conditions is the coefficient of friction extracted from a database in which are stored coefficients of friction simulated from various braking scenarios using representative models of the braking of the aircraft on the runway, the coefficient of friction of the aircraft landing on a runway being predicted from the actual data of the aircraft downloaded and from the data stored in the database.
• the actual data recorded in the aircraft's onboard computers is retrieved, decoded and filtered.
• the data is filtered by comparing the geolocation of the aircraft with corresponding runway geolocation data
• a weighting is assigned to the data according to the type of airplane and/or the frequency of acquisition of the data.
• the filtered data comprises geolocated and weighted data relating to the dynamics of the airplane, the type of airplane and braking, and a runway segment.
• the coefficients of friction are normalized in pressure, in braking energy and in speed.
• the method may further comprise a step of storing data relating to predicted coefficients of friction affected by a coefficient of friction.
• the invention also relates to a system for determining a coefficient of friction of an airplane on a landing strip, comprising a set of models representative of the braking of airplanes, during their landing, a database of simulated friction coefficients for various types of aircraft and various runway conditions and a model for predicting a braking coefficient from real data of the aircraft for which the friction coefficient is determined and from data stored in the database of simulated friction coefficients.
• FIG 1 is a diagram showing an airport landing strip equipped with a system for determining a coefficient of friction of the aircraft on the runway;
• FIG 2 illustrates the main phases of a method for determining a coefficient of friction of an airplane on a landing strip according to the invention;
• FIG 3 shows the simulation architecture of the system of figure 2
• FIG 4 is a diagram showing the different training phases of the models.
• FIG 5], [Fig 6], [Fig 7], and [Fig 8] illustrate the calculation of normalized friction coefficients used for runway characterization.
• figure 1 illustrates the general principle of the determination of a coefficient of friction of an airplane A during its landing on an airstrip P.
• the coefficient of friction is intended to be predicted from real data downloaded from the on-board computer of the airplane in which data are recorded during the flight, and in particular from data representative of the dynamics of the airplane , these data being compared with data from learning models to predict the evolution of the coefficient of friction as a function of time and of the position of the aircraft on the runway.
• airplanes are equipped with a braking control unit 1 which communicates with on-board maintenance aid systems 2 in order, in particular, to deliver data relating to the operation of the braking system. These data are recorded in the aircraft's on-board computer.
• the maintenance aid systems 2 communicate with a telecommunications interface 3, in order to transmit remotely, wirelessly, during landing, the data recorded in the on-board computer and supply them to a computing platform 4, comprising a server S in which the coefficient of friction of the aircraft is calculated then is transmitted to a local platform 5 hosted by the airport operator
• the data recovered from the on-board computers are for example downloaded at the end of the braking phase, in real time and delayed, for example after the plane has reached the arrival gate of the airport.
• the onboard data stored in the computer of the aircraft are transferred to the airline (step 8) and are stored on a server of the company (step 9).
• the data retrieved is the data which is recorded in the computer for the purposes of certification.
• QAR for "Quick Access Recorder”
• SAR for "Quick Access Recorder”
• step 12 these data can then be transferred from the airline's server directly to the calculation server 4 dedicated to calculating the runway conditions (step 10) and are stored there (step 11).
• this data is decoded.
• the raw data extracted from the server of the airline company can be decoded before their transfer to the calculation platform 4 so as to extract parameters relating to a precise flight phase (step 13) and a file is sent to the server of platform 4 (step 14).
• step 15 the data decoded during step
• step 16 After transfer to platform 4 or transferred during step 14 after decoding, are stored in the server of platform 4 then are filtered (step 16).
• the raw, undecoded data or the decoded data are transmitted to the server S of the platform 4 preferably using an SLTP link.
• uploaded data may include aircraft weight, aircraft center of gravity, aircraft type, wheel speed, throttle angle, airspeed aircraft, aircraft deceleration, brake system status, reverser status, spoiler status, brake pedal depression, brake system pressure, and brake piston displacement , wheel weight status, inertial data, aircraft GPS geolocation data, brake type, phase of flight, timestamp data, auto-braking status and pressure command of the braking system.
• the decoding carried out during step 12 includes the temporal cutting of the data frames to include only the phase of flight from touchdown to an aircraft speed of less than 20 knots (37 km/hour).
• the decoding delivers the landing data as long as the aircraft speed is above 20 knots or in the absence of an indicator indicating that the braking phase is complete.
• a time file with all of these parameters is stored on the server S of the computing platform 4.
• the server of the computing platform first proceeds to a sampling of the data, at a frequency for example comprised between 1 hertz and several hundred hertz depending on the different types of aircraft and configurations.
• the data transferred to the server of the local platform 5 are filtered, during step 16, so as, in particular, to recover the data relating to the dynamics and the geolocation of the aircraft.
• the decoded GPS data is compared with geolocation data for runway/airport pairs available in the airport operator's database. If the location does not match, the data is discarded.
• a general weighting is assigned for each set of flight data according to the type of aircraft and the type of frame (QAR, SAR, etc.) using a configurable configuration table and recorded on the calculation platform 4
• This table assigns a coefficient adjusted according to the type of aircraft and the frequency of acquisition. For example, for a type of aircraft whose data frame includes a limited number of data, for example for an aircraft type whose frame only has data relating to the braking pressure but does not include data relating at wheel speed, the weighting is lower than if the full data set is available.
• a frame sampled at 1 hertz such as a QAR frame, is assigned a lower coefficient than a SAR frame at 4 hertz.
• a vector of the various braking segments with their type and their weighting coefficient is generated, discarding the phases before touchdown and after the aircraft has reached a speed less than 20 knots.
• Filtered_data (runway_ID; aircraft_type; segment n; braking type; weighting coefficient), and Segment n (data for m; time; position) in which
• Filtered_data is the filtered output data; aircraft_type is the type of aircraft; runway_ID is a runway geolocation identifier; segment n corresponds to a segment of the runway data for m includes the following dynamic data: aircraft deceleration; aircraft speed; wheel speed; braking system pressure; brake pedal control; self-braking (step 10).
• the platform 4 includes a number of models 18 representative of braking. It is in particular a model of the aircraft representing its dynamics according to its aerodynamic characteristics, simulating its flight controls, its mass, its center of gravity, the thrust of its engine, the effect of the reverse thrust and spoiler, a model of the braking system and its regulation, and a runway model representing the maximum allowable friction and the friction resulting from the braking efforts.
• models 18 constitute a closed-loop simulation environment.
• braking simulation scenarios are also developed (step 19) and the simulation data is transmitted to the platform 4 (step 20) to be stored on a database of simulated friction coefficients 35a of the platform calculation server (step 21).
• the platform 4 thus comprises a simulation database 22 corresponding to various braking scenarios by varying different test conditions linked to the dynamics of the aircraft, to its characteristics, to the pilot's orders, to runway conditions, bearing in particular on the maximum admissible coefficient of friction,
• These data include, for example, simulation data relating to the type of aircraft, in particular to different aircraft masses or different landing speeds, to braking, in particular to different braking profiles, to different brake pedal controls , autobraking, thrust reverser and spoilers, different maximum allowable friction coefficients. Some of these scenarios are the result of a configuration as close as possible to real flights.
• the data from the simulation scenarios are used to train models representative of the braking of airplanes during their landing, for various braking scenarios.
• the trained models are then stored in the platform 4 server (step 24)
• simulation data relating to runway conditions stored in database 22 is provided to a runway model 25.
• the simulation data relating to the type of airplane are transmitted to an airplane model 26 while the simulation data relating to the braking are transmitted to a model 27 of the braking system.
• the models are therefore implemented, trained and tested according to a phase which therefore begins with a simulation data loading phase 30, for various braking scenarios, a flight breakdown phase 31, by decoding for retaining the data from the touch or “touch down” up to a limit speed value fixed for example at 20 knots and a data processing step 32 in which these data are digitized and additional variables are calculated.
• the next step 33 corresponds to training the models with the simulation data so as to obtain, at the output, simulated friction coefficient values.
• step 34 the real data of the airplane is recovered, which are decoded then filtered and injected into a prediction module 35 of the platform 4.
• the prediction compares the real data file to those corresponding to the training model scenario, in time series, to reconstruct the friction value at each time step.
• the values of the friction coefficients are then stored in memory in a database 35a of simulated friction coefficients, for various types of aircraft and various runway conditions (step 36).
• the prediction algorithm uses either a random forrest type algorithm, for example with a smoothing effect over a range of 100 to 300 samples depending on the refresh rate of the input data, or on a neural network, for example eight floors.
• step 33 of training the models is followed by a phase 37 of evaluating the models.
• model evaluation is implemented, for example by regression, classification or real-time prediction.
• MAE mean absolute error
• n number of time steps of the scenario
• t no time
• yt value of theoretical m
• the shape of the resulting friction curve is compared with the result of the scenarios of the training model to define whether or not the maximum friction coefficient admissible by the track has been reached. If this maximum coefficient of friction value is not reached, a characterization of the maximum coefficient of friction seen by the aircraft is defined.
• the maximum value of the coefficient of friction m Pac is however in practice difficult to obtain without implementing powerful and complex means of calculation on the one hand; and on the other hand actually available in less than 1% of cases. This is in particular the case when the coefficient p max is calculated as a function of the slip.
• a normalized braking coefficient value m h is thus calculated, in order to make comparisons between aircraft and between braking points.
• braking energy which is the average of the energy during a given period of time - here experienced at one second (E).
• the normalization of the coefficient of friction is carried out in braking gain (figure 5), in braking pressure (figure 6), in braking energy (figure 7).
• the coefficient m is first of all increased by homothety of the average profile of braking gain to pass from the aircraft considered (Aircraft 1 or Aircraft 2) to a reference aircraft (Reference Aircraft).
• This normalization step thus consists in processing the coefficient of friction so as to characterize it in a reference frame of values of pressure, braking energy and predetermined speeds, so that the frictional effort is only related to the track.
• This normalized friction coefficient value is then used to make the acquisitions comparable and to implement a characterization of the track or of track segments.
• the result of the predictions assigned a weighting coefficient is stored in a file and then stored in a server.
• the method further comprises a step 38 of transferring the results of the calculations of the coefficients of friction.
• They can thus be used by other applications, such as that which is implemented by the platform 5 for calculating runway conditions of the airport, or other tools for optimizing operational costs, or even for on-board applications for anticipating braking procedures.

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• Engineering & Computer Science (AREA)
• Aviation & Aerospace Engineering (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Transportation (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Life Sciences & Earth Sciences (AREA)
• Atmospheric Sciences (AREA)
• Regulating Braking Force (AREA)
• Traffic Control Systems (AREA)
• Braking Arrangements (AREA)

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• 2021
  • 2021-07-27 FR FR2108133A patent/FR3125800A1/fr active Pending
• 2022
  • 2022-07-25 CN CN202280053145.0A patent/CN117716407A/zh active Pending
  • 2022-07-25 EP EP22755266.8A patent/EP4377941A1/de active Pending
  • 2022-07-25 WO PCT/FR2022/051492 patent/WO2023007083A1/fr active Application Filing

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