Method for controlling the braking of aircraft wheels and associated wheel braking control device - Patents.com

Abstract

The present invention relates to a method for monitoring aircraft wheel braking, in which an aircraft wheel braking controller 14 controls aircraft wheel braking by actuating wheel brakes 10 based on both a deceleration modulation request 16 and a thrust reverser deployment request 24.

Description

[Technical field]

[0001] The present invention relates to the field of aircraft braking, and more particularly to an improved braking method for aircraft. [Background technology]

[0002] In an aircraft, several sources can cause the aircraft to brake during the landing phase or during an aborted takeoff.

[0003] As shown in Fig. 6, there are mainly two sources dedicated to this braking function, the triggering of which is independent of the cockpit for different actions of the pilot: the braking system with the wheel brakes 10 and the thrust reverser system with the thrust reversers 12. The wheel brakes 10 are controlled from a wheel braking controller 14, which receives a deceleration regulation request 16 coming from the cockpit 18 and issues a deceleration regulation command 20 for the wheel brakes 10. The thrust reversers 12 are controlled from a thrust reverser controller 22, which receives a thrust reverser deployment request 24 coming from the cockpit 18, from which the actions of the pilot 26 arrive, and issues a thrust reverser deployment command 28 for the thrust reversers 12.

[0004] The wheel braking system included in the landing gear of an aircraft is capable of ensuring the braking function of the aircraft by itself. In fact, the certification of the braking distance applies only to the wheel braking system. It is the only system taken into account to determine whether an aircraft can land on a particular runway. However, to facilitate this certification, the thrust reverser system included in the turbojet engine of the aircraft is very often considered as an option to be used to reduce the wear of the wheel braking system, especially since these two systems are developed completely independently, since each of them relates to very different aircraft subsystems (landing gear and turbojet engine).

[0005] One of the main functions of the wheel braking system is to slow the aircraft evenly (without jolts), to accommodate and overrun the runway (the "brake relief" function) and to ensure coordinated deceleration (the "autobrake" function).

[0006] FIG. 7, for example, shows a typical case of a coordinated landing with a constant deceleration level with thrust reversers deployed during braking.

[0007] The time of the wheels' contact with the ground is first observed at reference 1, allowing the initialization of the wheel braking algorithms. At reference 2, once these wheel braking algorithms are initialized, the deceleration adjustments are activated when a certain wheel speed value is reached. The wheel brakes start their operation and the aircraft is servo-controlled to a certain deceleration setpoint. At a predetermined time 3, unknown to the wheel braking system, the thrust reversers are deployed at the action of the pilot. This deployment of the thrust reversers causes a strong deceleration that is considered by the wheel braking system as an external disturbance, which must then be adapted in real time to eliminate (remove) this disturbance. This entire period creates a short period during which the deceleration is not equal to the setpoint, thus causing jerks in the aircraft that significantly reduce passenger comfort. At reference 4, once the thrust reversers are deployed, the wheel braking adjustments manage to eliminate the disturbance caused by the deployment of the thrust reversers, again regulating the aircraft to the certain deceleration setpoint. The desired (zero or non-zero) speed is reached at reference number 5 and the pilot deactivates the automatic deceleration function of the wheel braking system, thereby cancelling deceleration.

[0008] However, the comfort problem associated with this recurrent jerk poses a substantial problem that must be solved, which is in particular dimensioned to the amplitude of the jerk as a corrector that allows deceleration adjustment, causing loss of performance of the wheel braking system. In fact, to correctly eliminate this relatively large disturbance (up to 50% of the deceleration), a very dynamic corrector is needed to guarantee the comfort of the rest of the braking. However, conversely, to filter out what may be felt as a "jolt", a rather less dynamic corrector is needed. The compromise between these two constraints therefore makes it difficult to find and leads to finding other solutions to guarantee better comfort for these passengers. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to propose an alternative solution making it possible to ensure a smoother deceleration of the aircraft. It is also an object of the present invention to provide more freedom in the design of the wheel braking system, and in particular to facilitate the compromise of the adjustment of the aforementioned collectors. [Means for solving the problem]

[0010] These objects are achieved by a method for monitoring aircraft wheel braking in which the braking of the aircraft wheels is controlled by a wheel braking control device which actuates the aircraft wheel brakes based on both a deceleration modulation request and a thrust reverser deployment request.

[0011] In this manner, thrust reverser behavior is communicated to the wheel braking control system, facilitating the compromise of adjustable correction required in the prior art.

[0012] According to contemplated embodiments, a thrust reverser deployment request is received from the aircraft cockpit directly by the wheel braking controller, or directly by the wheel braking controller and relayed to a thrust reverser controller which actuates thrust reverser deployment, or directly by a thrust reverser controller which relays to the wheel braking controller.

[0013] Advantageously, in order to eliminate disturbances caused by the deployment of the thrust reverser, the deceleration regulation command issued by the wheel braking control is kept substantially constant by adapting the deceleration setpoint proportional to the disturbances caused by the deployment of the thrust reverser or by adapting a gain in the transfer function of the wheel braking regulation loop proportional to the disturbances caused by the deployment of the thrust reverser.

[0014] The present invention also relates to a wheel braking control device capable of activating the brakes of an aircraft's wheels based on a deceleration adjustment request, the wheel braking control device being configured to activate the brakes of the aircraft's wheels also based on a thrust reverser deployment request.

[0015] Preferably, the controller is further configured to receive information regarding the actual state of the thrust reverser from a thrust reverser controller.

[0016] Other characteristics and advantages of the present invention will become apparent from the following description, with reference to the attached drawings which illustrate exemplary embodiments thereof, without in any way limiting said exemplary embodiments. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 shows a simplified basic concept of a wheel braking and thrust reverser system according to a first embodiment of the present invention. [Diagram 2] FIG. 2 shows a simplified basic concept of a wheel braking and thrust reverser system according to a second embodiment of the present invention. [Diagram 3]FIG. 3 shows a simplified basic concept of a wheel braking and thrust reverser system according to a third embodiment of the present invention. [Figure 4] FIG. 4 shows in detail the structure of the wheel braking control device of the present invention. [Diagram 5] FIG. 5 shows the deceleration curve obtained with the wheel braking control device of FIG. [Figure 6] FIG. 6 shows a simplified conceptual wheel braking and thrust reverser system of the prior art. [Figure 7] FIG. 7 shows the deceleration curve of the wheel braking system of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Three embodiments of the invention shown in succession in FIGS. 1 to 3 are envisaged for securing information from a wheel braking control device.

[0019] In the embodiment of FIG. 1, it is merely proposed that, in accordance with the known basic concept, a thrust reverser deployment request 24 sent exclusively to the thrust reverser controller 22 directly from the aircraft cockpit 18 is also sent in parallel to the wheel braking controller 14.

[0020] However, with this basic concept, the deceleration profile is not optimal, since the wheel braking control has no control over the time at which the thrust reversers are deployed and therefore does not know their actual state. It only reacts in relation to the deployment request made by the pilot and can presume that the deployment is actually taking place. As a result, there is a risk of taking into account a command to deploy the thrust reversers while they are not deployed, which causes transient phenomena that are very detrimental to braking comfort and performance (deceleration of lower effectiveness than commanded). However, this risk can be eliminated by receiving information 30 about the actual state of the thrust reversers from the thrust reverser control, making it possible to verify that the thrust reversers are properly deployed.

[0021] It should be noted that this basic concept allows very simply to return to the previous basic concept where wheel braking and thrust reverser deployment are managed independently of each other in a degraded mode where deployment requirements are not taken into account.

[0022] In the embodiment of FIG. 2, it is proposed that the thrust reverser controller 22 relays thrust reverser deployment requests 24 received directly from the cockpit 18 to the wheel braking controller 14 .

[0023] As mentioned before, in this basic concept, the deceleration profile is not optimal either, since the wheel braking control has no control over the time at which the thrust reversers are deployed and therefore does not know their actual state. It reacts only with respect to the deployment request received from the thrust reverser control and can only deduce that the deployment has actually taken place. As a result, there is a risk of taking into account a command to deploy the thrust reversers while they are not deployed, which would cause transient phenomena very detrimental to braking comfort and performance. However, as before, this risk can be eliminated by receiving information 30 about the actual state from the thrust reverser control, making it possible to verify that the thrust reversers are properly deployed.

[0024] This basic concept also allows a very simple return to the typical basic concept where wheel braking and thrust reverser deployment are managed independently of each other, by selecting in degraded mode not to take into account the deployment requirements and possible state of the thrust reversers.

[0025] 3, the deceleration adjustment request 16 and the thrust reverser deployment request 24 are both sent to the wheel brake controller 14, which can then choose to relay the thrust reverser deployment request to the thrust reverser controller 22, for example, only when it is ready to take effect. Once the request has been relayed to the thrust reverser controller 22, the thrust reverser controller 22 can acknowledge successful receipt to the wheel brake controller and send back information 30 regarding the actual status of the thrust reversers, such as not deployed, deployed, or deployed.

[0026] This master (for brakes)-slave (for thrust reversers) type of operation allows the deceleration adjustment algorithm to be fully adapted from the actual state of the thrust reversers, optimizing the aircraft deceleration as much as possible. It is also possible to recreate the thrust reverser induced deceleration (for example, by an inverse model delivering back the instantaneous deceleration delta, or predicted at some step earlier than the wheel brake controller) and directly integrate it into the deceleration adjustment, to make it easier to eliminate disturbances due to thrust reverser deployment. This can be done by the thrust reverser controller or the wheel brake controller, which receive the model data needed for the adjustment.

[0027] 4 shows an exemplary embodiment of a wheel braking control device 14 which issues a deceleration regulation command 20 for the wheel brakes 10 from a deceleration regulation request 16. This control device has a collector 32 acting in a known manner on the regulation deviation between a setpoint 34 and the measured value of this deceleration 21. However, this setpoint is not a nominal deceleration setpoint 36 but an adapted deceleration setpoint delivered by a setpoint adaptation module 38 which receives a thrust reverser deployment request 24 and possibly information 30 on the actual state of the thrust reversers 12. This setpoint adaptation module 38 thus allows a switchover from the nominal deceleration setpoint to an adapted deceleration setpoint. The wheel braking control device can thus directly change its deceleration setpoint in line with the thrust reverser deployment request so that the braking effect of the thrust reversers and the wheel braking setpoint correspond to the values ​​requested in the aircraft cockpit.

[0028] The progression from the nominal deceleration setpoint to the adaptive deceleration setpoint that allows to guarantee a jolt-free deceleration regulation command 20 is shown in FIG. 5. In FIG. 5, the ideal case is shown in which the adaptive deceleration setpoint 34 is reduced as soon as it is known that the thrust reversers are moving (received thrust reverser deployment request 24) at time T1. This setpoint then changes exactly inversely to the deceleration effect generated by the thrust reversers (the hatched area 40 corresponds to the compensation for the aerodynamic effect of the thrust reversers). Naturally, the objective is to have a constant deceleration corresponding to the value requested by the pilot. Once the deployment of the thrust reversers is completed at time T2, the deceleration setpoint returns to the constant value of the nominal deceleration setpoint 36 in order not to accelerate too much and to have minimal oscillations during the transient.

[0029] It should be noted that there are other types of adaptations that can have the same result as the setpoint adaptation described above. For example, an adaptation of the gain of the transfer function of the closed loop system is also possible. For this, the gain of the regulation loop is modified at the time of an event defined by the thrust reverser deployment request and the state of these thrust reversers.

[0030] The main advantage of this solution is therefore to obtain a very smooth aircraft deceleration and thus increase passenger comfort during the landing phase.The transfer of data between the two control systems therefore allows the aircraft behavior to be predicted.

[0031] Each of these three embodiments involves an increase in the number of signals transmitted between the cockpit and the two control devices, and therefore in particular an increase in wiring. However, this drawback must be kept in perspective, since it essentially depends on the communication network present in the aircraft. However, with current AFDX type (avionics full duplex) networks, the need for additional wiring tends to disappear. The present disclosure also includes the following inventions. The first aspect is 1. A method for monitoring wheel braking of an aircraft, comprising: A method in which braking of an aircraft's wheels is controlled by a wheel braking control system (14) that actuates wheel brakes (10) of the aircraft based on both a deceleration modulation request (16) and a thrust reverser deployment request (24). The second aspect is In a first aspect, the method further comprises receiving a thrust reverser deployment request (24) directly from the aircraft cockpit (18) by the wheel braking control device. The third aspect is In a second aspect of the method, the thrust reverser deployment request (24) received directly by the wheel braking control is relayed to a thrust reverser controller (22) which activates deployment of a thrust reverser (12). The fourth aspect is In a first aspect of the method, the thrust reverser deployment request (24) is received directly by the thrust reverser controller (22), which relays the thrust reverser deployment request (24) to a wheel braking controller (14). The fifth aspect is The method according to any one of the first to fourth aspects, wherein the deceleration adjustment command (20) issued by the wheel braking control device (14) to the wheel brakes (10) is kept substantially constant by adapting a deceleration setpoint (36) proportional to the disturbance caused by the deployment of the thrust reverser (12) to eliminate the disturbance caused by the deployment of the thrust reverser. The sixth aspect is The method according to any one of the first to fourth aspects, wherein the deceleration regulation command (20) issued by the wheel braking control device (14) to the wheel brakes (10) is kept substantially constant by adapting a gain in a transfer function of the wheel braking regulation loop in proportion to the disturbance caused by the deployment of the thrust reverser (12) to remove the disturbance caused by the deployment of the thrust reverser. The seventh aspect is The method according to any one of the first to sixth aspects, wherein information (30) about an actual state of the thrust reverser is sent to the wheel braking control device (14). The eighth aspect is A wheel braking control device (14) capable of actuating wheel brakes (10) of an aircraft based on a deceleration adjustment request (16), comprising: The wheel braking control system (14) is characterized in that it is configured to actuate the aircraft wheel brakes (10) based also on a thrust reverser deployment request (24). The ninth aspect is The control device according to an eighth aspect, wherein the wheel braking control device (14) is further configured to receive information (30) regarding the actual state of the thrust reverser from the thrust reverser control device (22). A tenth aspect is An aircraft having a wheel braking control device (14) according to an eighth or ninth aspect.

Claims

1. 1. A method for monitoring wheel braking of an aircraft, comprising:

1. A method in which braking of an aircraft's wheels is controlled by a wheel braking control (14) that activates wheel brakes (10) of the aircraft when both a deceleration modulation request (16) and a thrust reverser deployment request (24) are input to the wheel braking control (14).

2. 2. The method of claim 1, wherein the thrust reverser deployment request (24) is received by the wheel braking control directly from a cockpit (18) of the aircraft.

3. 3. The method of claim 2, wherein the thrust reverser deployment request (24) received directly by the wheel braking control is relayed to a thrust reverser controller (22) which actuates deployment of thrust reversers (12).

4. 4. The method of claim 3, wherein the thrust reverser deployment request (24) is received directly by the thrust reverser controller (22), which relays the thrust reverser deployment request (24) to a wheel braking controller (14).

5. 5. The method according to claim 3 or 4, wherein the deceleration adjustment commands (20) issued by the wheel braking control (14) to the wheel brakes (10) are kept substantially constant by adapting a deceleration setpoint (36) proportional to the disturbances caused by the deployment of the thrust reversers (12) in order to eliminate disturbances caused by the deployment of the thrust reversers (12).

6. 5. The method according to claim 3 or 4, wherein the deceleration modulation commands (20) issued by the wheel braking control (14) to the wheel brakes (10) are kept substantially constant by adapting a gain in a transfer function of a wheel braking modulation loop in proportion to the disturbance caused by the deployment of the thrust reverser (12) in order to eliminate the disturbance caused by the deployment of the thrust reverser (12).

7. 7. The method according to claim 3, 4 or 6, wherein information (30) about the actual state of the thrust reverser is sent to the wheel braking control (14).

8. A wheel braking control device (14) capable of activating brakes (10) of wheels of an aircraft based on a deceleration adjustment request (16), comprising:

1. A wheel braking control system (14) configured to activate wheel brakes (10) of an aircraft when both a deceleration adjustment request (16) and a thrust reverser deployment request (24) are input to the wheel braking control system (14).

9. 9. The wheel brake control system (14) according to claim 8, characterized in that the wheel brake control system (14) is further configured to receive information (30) regarding the actual state of the thrust reverser from the thrust reverser control system (22).

10. An aircraft comprising a wheel braking control device (14) according to claim 8 or 9.

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