FR3017848A1 - SPEED LIMITATION METHOD FOR AEROPORTUARY VEHICLE - Google Patents

Abstract

The vehicle, preferably an airport vehicle, comprises: a traction engine (10); - a gearbox (11) transmitting the rotation of the engine to the wheels (14) of the vehicle; - a control system (15) of the gearbox (11); a sensor for measuring the speed of movement of the vehicle; wherein the control system applies a method of limiting the speed of movement of the vehicle by automatically shifting the gearbox to neutral when the speed of movement of the vehicle exceeds a threshold.

Description

The present invention relates to the field of airport assistance equipment, in particular aircraft ground equipment which is also commonly referred to by the abbreviation GSE (Ground Support Equipment). The invention relates more particularly to the ground equipment for aircraft of the motor vehicle type such as belt luggage loaders, catering vehicles, etc ...

These airport vehicles provide service for aircraft, particularly aircraft, on the airport service area between flights and are therefore required to evolve in their immediate vicinity. Some of these vehicles are brought to dock the aircraft, which is particularly the case of aircraft bandgage loaders. However, these vehicles should not come into contact too hard with the fuselage of the aircraft so as not to damage it. In order to secure the docking of the vehicles to the aircraft, the procedures provide that their approach speed is limited step by step in order to reduce or eliminate any risk of damage to the fuselage of the aircraft in case of accidental contact.

In the case of airport vehicles including a heat engine to ensure their movement, the gearboxes usually have the particularity of having an automatic disengagement device provided by a hydraulic torque converter. In other words, the torque converter automatically disengages when the engine is idling - that is to say, the driver does not request the accelerator pedal - while a speed is engaged in accordance with that selected by the driver. manual gear selector. However, when a gear is engaged and the engine is idling, the torque converter can maintain a slight residual drive, which keeps the transmission kinematics moving. The vehicle moves forward or backward - depending on the direction of travel applied - then at a traveling speed, commonly known as "box drag". If the can drag speed is greater than the desired travel speed, the driver shall apply the service brake to reduce the speed of travel to that desired. Similarly, the driver must request the service brake if he wishes to completely stop the vehicle.

In practice, the can drag speed is often greater than 5 km / h, or sometimes 10 km / h Such speed is greater than that tolerated in areas close to aircraft, including aircraft. Indeed, the speed of movement C: \ Users \ Yves \ Desktop \ Documents \ 1- Customers \ HIRS \ HIRS-R2-35516TLDE-TLD Regulation speed slow on gearbox \ 35516 TLDERegulation-speed limitation - 250214 version depot. The maximum allowed docx of the vehicle is generally less than or equal to 7 km / h in a first zone close to the aircraft and less than 1 km / h in an area even closer to it. The effect of box drag has the disadvantage that the vehicle can reach a speed of travel greater than that allowed, particularly in areas close to the aircraft, despite the fact that the driver has lifted his foot from the accelerator pedal. Indeed, the driver may not be aware of the exceeding of the authorized speed and for this reason or for any other reason, omit to ask the service brake to limit its speed or stop the vehicle. In the extreme case, it can result in an impact with the fuselage of the aircraft with sufficient brutality to damage the latter. The object of the present invention is to provide a solution at least partially overcoming this disadvantage. More particularly, the invention aims to prevent the vehicle from exceeding the maximum travel speeds allowed in the areas close to the aircraft. To this end, the present invention proposes a method for limiting the speed of movement of a motor vehicle, preferably an airport vehicle, which vehicle comprises a traction engine and a gearbox to transmit the rotation of the engine to vehicle wheels, the method comprising a step a) of automatically switching the gearbox to neutral when the speed of movement of the vehicle exceeds a first threshold. According to a first preferred embodiment, the method further comprises a step b) after step a), step b) of automatically recommitting the transmission of the rotation of the engine to the wheels by the gearbox when the speed the vehicle moves below a second threshold below the first threshold. Advantageously, in step b), the automatic reengagement of the transmission is operated by again passing the speed that was selected when the gearbox was automatically switched to neutral in step a). Furthermore, it is advantageous if step b) is performed provided that the rotational speed of the motor is below a given threshold; According to a second preferred embodiment, step a) comprises the following successive substeps: al) automatically reversing the direction of travel on the gearbox when the speed of movement of the vehicle exceeds the first threshold; and a2) automatically shifting the gearbox to neutral when the vehicle traveling speed falls below a second threshold lower than the first threshold.

In this second preferred embodiment, the method can be advantageously used to stop the vehicle, in which, in the sub-step a2), the passage of the gearbox in neutral is performed when the speed of movement of the vehicle is zero. Furthermore, it is advantageous that step a2) further comprises inhibiting the reengagement of a speed by the gearbox until the manual speed selector of the gearbox has been previously passed. manually in neutral. More generally, according to the invention it is advantageous to ensure the transmission by the gearbox of the rotation of the engine to the wheels of the vehicle through a hydraulic torque converter ensuring automatic disengagement of the automatic transmission. The invention also proposes an airport vehicle, comprising: - a heat engine (for traction of the vehicle - wheels supporting the vehicle - a gearbox transmitting the rotation of the engine to the wheels supporting the vehicle - a control system of the gearbox - a sensor for measuring the speed of movement of the vehicle which sensor is connected to the control system of the gearbox, in which the control system is arranged to apply the method according to the invention described above Advantageously, the gearbox comprises an automatic hydraulic clutch torque converter and the gearbox control system can advantageously be provided to selectively apply a first operating mode and a second operating mode, in which: the first mode of operation consists in applying the method according to the first embodiment preferred embodiment described above wherein the first threshold is set to a first predetermined value; and the second mode of operation consists in applying the method according to the second preferred embodiment described above in which the first threshold is set at a second predetermined value less than the first predetermined value. Advantageously, the first predetermined value is between and 7 km / h and the second predetermined value is between 0.5 and 0.9 km / h. Furthermore, it is advantageous for the vehicle to comprise a proximity detector of the vehicle with an aircraft, in which the vehicle control system the gearbox applies the second mode of operation when the proximity of the vehicle with an aircraft is detected by the proximity detector. The proximity detector may advantageously comprise a three-dimensional vision device with shape and object recognition, the predetermined parameters comprising at least one operating state diagnostic of the vision device. Other characteristics and advantages of the invention will appear on reading the following description of a preferred embodiment of the invention, given by way of example and with reference to the appended drawing. Figure 1 shows schematically an airport vehicle according to the invention, in this case a belt loader bag, in position in front of an aircraft to load or unload baggage. FIG. 2 schematically represents an example of zoning around an aircraft defining different maximum authorized speed levels for the movement of the airport vehicle of FIG. 1.

Figure 3 schematically illustrates the main hardware elements of the vehicle involved in the implementation of the method according to a preferred embodiment of the invention. FIG. 4 represents diagrams illustrating the method of limiting and regulating the speed of the vehicle of FIG. 1 in an area close to an airplane.

Figure 5 shows diagrams illustrating the method of limiting and braking the vehicle of Figure 1 in an area even closer to the aircraft. The method of the invention is advantageously applicable to a motor vehicle comprising a traction engine and a gearbox to transmit the rotation of the engine to the wheels of the vehicle to move the vehicle.

According to the method, the speed of movement of the vehicle is limited by automatically shifting the gearbox to neutral when the speed of movement of the vehicle exceeds a threshold that can be predetermined. By shifting it to neutral, the gearbox ceases. to transmit the rotation of the engine to the wheels of the vehicle. No longer subject to traction, the vehicle will decelerate as soon as it is on flat ground or in a climb instead of continuing to increase as was the case before passage to neutral. According to a preferred embodiment, not only is the speed of movement of the vehicle limited, but it is regulated. For this, after having automatically switched to the neutral position of the gearbox, the transmission of the rotation of the engine to the wheels by the gearbox is automatically reengaged when the speed of movement of the vehicle falls below a second threshold lower than first threshold. As a result, the speed of travel tends to increase again as a result of the transmission of the rotation of the motor to the wheels. When the speed of movement of the vehicle reaches the first speed threshold again, the transmission is again in neutral and so on. The difference between the first threshold and the second threshold therefore defines a hysteresis. The hysteresis value is chosen to provide the desired control flexibility. According to another preferred embodiment, it is not enough to pass the gearbox in neutral to limit the speed when the speed of movement of the vehicle exceeds the chosen threshold, but we will actively force the limitation of the speed to a value below the threshold considered. For this, when the threshold is detected, it automatically reverses automatically the direction of travel on the gearbox, which has the effect of actively decelerating the vehicle due to the motor soliciting it in the direction opposite movement. When the speed of movement of the vehicle passes below a second threshold below the first threshold, the gearbox is automatically shifted into neutral. According to this preferred embodiment, it can be advantageously provided to automatically switch the gearbox to neutral when the speed of movement of the vehicle has become zero. Thus, the vehicle is stopped without restarting in the opposite direction of travel. The method according to the invention is particularly suitable for airport vehicles serving the aircraft in order to limit the risks of too abrupt collision of the vehicle with the fuselage of an aircraft, since they operate on a flat and horizontal ground in the proximity of the aircraft. aircraft. We will in the following describe in more detail an example of implementation of an airport vehicle vehicle according to the invention with reference to the figures.

As illustrated in FIG. 1, it is in this case a vehicle 1 constituting a belt loader for the service of an aircraft A, but it can be any other type of airport vehicle intended for the ground service of an aircraft It includes a driving position 4 which may optionally include a closed cabin or not. But as will be seen, the control system according to the invention is independent of the sensitive bumper 3. FIG. 2 illustrates an example of zoning around the aircraft A defining different maximum speed levels authorized for the movement of the airport vehicle . In an area remote from the aircraft (commonly referred to as a ramp area) which is referenced 5, the vehicle is authorized to move, either without limitation of its traveling speed, or with a speed limited to a maximum authorized speed relatively depending on the country and the practice of the airport concerned.

For example, European legislation imposes a maximum permissible speed of 25 km / h Respect for this speed limitation is generally obtained by clamping the engine at the factory by the manufacturer of the airport vehicle. This zone 5 called ramp area usually corresponds to any point remote from the aircraft at least a minimum distance defined generally between 6 and 9 m. Below this minimum distance from the aircraft, the vehicle enters a so-called danger zone (commonly referred to as a safety area) referenced 6. In this zone, the speed of movement is limited to a maximum authorized speed which is less than to that applicable where applicable in zone 5 called ramp area. The maximum authorized speed is generally between 4 and 7 km / h depending on the type of vehicle concerned. In order to enforce this speed limit, the airport vehicle includes a system for limiting the speed of movement of the vehicle. When the vehicle is in zone 5 called ramp area, the speed limitation system is inactive, except for the case of vehicles also using the speed limit system to impose a maximum speed allowed in the area 5 called ramp area. When the vehicle enters danger zone 6, the speed limitation system is activated. Generally, the speed limitation system is activated manually by the driver by actuating a corresponding controller, for example by pressing a button arranged on the dashboard of the vehicle. Alternatively, it is activated automatically by a system for measuring the distance from the vehicle to the aircraft that can be equipped with the vehicle. Once the speed limitation system is activated, it enters a mode of operation called "danger zone" mode in which it prevents the vehicle from moving at a speed greater than that authorized in the danger zone. Of course, in the case of vehicles that also use the speed limitation system to impose a maximum authorized speed in zone 5 called ramp area, the aforementioned manual or automatic activation corresponds in fact to the passage of the speed limitation system. an operating mode called "ramp area" mode in which it imposes a limitation on the maximum speed allowed in zone 5, in the "danger zone" mode mentioned above, in which it imposes a limitation on the maximum authorized speed in the zone 6. In addition, light and / or sound signals (not shown) provided on the vehicle are activated at the same time as the system. me speed limit. The light signals are located on the one hand on the dashboard 4 or in the vehicle cabin (if provided) and on the other hand outside the vehicle. These signals inform the driver of the vehicle and an airport watchdog that the speed limitation system is activated and imposes on the vehicle the speed limit applicable in the danger zone 6. When the vehicle is closer to the airplane , ie at a distance from the aircraft lower than a value generally defined between 1.5 and 2.5 m, the vehicle enters a so-called docking area (commonly referred to as dock area) referenced 7. In this In this zone, the speed of movement of the vehicle is limited to a maximum authorized speed lower than that defined for the danger zone 6. The maximum authorized speed in the approach zone 7 is set to a value for which the vehicle's contact with the plane does not cause damage to the fuselage of the aircraft. The maximum speed allowed in docking area (commonly called safe docking speed) is generally between 0.5 and 0.9 km / h depending on the weight of the vehicle. Here again, the system for limiting the speed of movement of the vehicle is provided to enforce this maximum authorized speed. For this, the speed limitation system changes from the "danger zone" mode in which it applies the speed limitation applicable to the danger zone 6 to another mode - called "docking zone" mode - in which it applies the speed limit applicable to the landing zone 7. The passage of the speed limitation system from the "danger zone" mode to the "docking zone" mode is preferably automatic. For this, the vehicle comprises a proximity detector which detects whether the vehicle is at a distance from the aircraft less than or equal to that defining the docking area 7. When the proximity of the aircraft is thus detected, the system of speed limit switches to "docking zone" mode. The proximity detector may advantageously comprise a three-dimensional vision device with recognition of shape and object to detect the aircraft. Alternatively or in a complementary manner, the passage of the speed limit system from the "danger zone" mode to the "docking zone" mode is manually caused by the driver by actuating a corresponding control member. When the speed limitation system is in the "docking zone" mode, the lights and / or sound signals, different from those of the "danger zone" mode, are activated on the vehicle to inform the driver. Finally, in case of contact of the vehicle with the fuselage of the aircraft, which corresponds to the area referenced 8 in Figure 2, a vehicle control system causes the immediate stop of the vehicle and prevents the activation of walking before the latter. As illustrated in FIG. 1, the contact of the vehicle 1 with the fuselage F of the aircraft A can be detected by a sensitive bumper 3 arranged at the front end of the vehicle. In our example, the sensitive bumper 3 is arranged at the front end of the conveyor system 2. The sensory bumpers are known per se, an example being described in US 7,268,676 B2. But as will be seen, the displacement speed limitation system according to the invention is independent of the sensitive bumper 3.

The system for limiting the speed of movement of the vehicle 1 which implements a method according to the invention is explained in more detail below with reference to FIG. 3. The vehicle 1 comprises a heat engine 10 for the traction of the vehicle of which the shaft is coupled to a gearbox 11. The gearbox 11 comprises a hydraulic torque converter providing an automatic disengagement function. The gearbox 11 transmits the rotation of the motor 10 on its output shaft 12 with a transmission ratio. The rotational movement of the output shaft 12 is transmitted to the wheels 14 of an axle 13. For convenience, only the traction wheels of the vehicle 1 have been shown. The gearbox is controlled by a control system 15. The control system 15 is able to move the gearbox to neutral, also commonly called neutral point, position in which the gearbox no longer transmits the rotation of the gearbox. at its output shaft 12. The control system 15 is also able to move forward of the gearbox. In the case where the gearbox 11 has several transmission ratios, the control system 15 is able to engage any ratio - still commonly called speed - of the gearbox 11. Similarly, the control system 15 is able to pass the reverse gearbox. The vehicle includes a manual gear selector 21 at the driving position 20 of the vehicle 1. The manual gear selector 21 allows the driver to select reverse gear, neutral or forward gear or any of the speeds forward if the gearbox has multiple speeds, that is, several discrete transmission ratios. The speed selector information of the selector 21 is supplied to the control system 15, which is shown schematically by the line referenced 19. In the non-speed limiting operating mode, the control system 15 operates the gearbox 11. in correspondence with the speed selection information of the selector 21. The vehicle speed control system 1 comprises the control system 15 of the gearbox 11. The control system 15 also receives the speed of travel of the 1, which is shown schematically by the line referenced 17. The speed of movement of the vehicle 1 can be determined from the signal provided by a sensor, not shown, measuring the rotational speed of the output shaft 12 of the gearbox 11.

When the vehicle 1 leaves the zone 5 called ramp area to enter the danger zone 6, the vehicle speed limitation system 1 is activated manually or automatically as appropriate and applies the "danger zone" mode, as explained above with reference to FIG. 2. This activation takes place by the fact that the manual or automatic activation device supplies the control system 15 with a corresponding signal (not symbolized in FIG. 3) as a result of which the control system control 15 will limit the movement speed to the maximum speed allowed in the danger zone as follows and illustrated in FIG. 4.

In FIG. 4, the curve of diagram (a) illustrates the speed 'V' of displacement of vehicle 1 along the ordinate as a function of time 't' on the abscissa while the curve of diagram (b) gives the operating mode, noted 'BV', of the gearbox 15 in ordinate according to the same axis of time 't' in abscissa as for the diagram (a).

At the instant t = 0, the speed of the gearbox 11 is engaged, which is represented by the position marked '1' on the ordinate of the diagram (b) .The fact that the first gear is engaged. is the consequence of the fact that the control system 15 has applied it to the gearbox 11 in accordance with the speed selection at the manual gear selector 21.

As illustrated, it may happen that the traveling speed V of the vehicle 1 increases and reaches the maximum speed allowed in the danger zone 6, noted V1 in the diagram (a) of FIG. 4. In particular, the increase speed may be due to the drag effect of box when the gearbox 11 includes a torque converter for the automatic disengagement of the transmission of the engine to the wheels and that the driver fails to request the service brake to limit the speed of the vehicle 1 although it has stopped pressing the accelerator pedal. But as soon as the moving speed V of the vehicle 1 exceeds the maximum authorized speed V1, the control system 15 puts the gearbox 11 in neutral, noted N in the diagram (b). As a result, the speed of movement of the vehicle 1 decreases because it is no longer driven by the engine 10, including a residual drive related to the box drag effect, it being recalled that the vehicle 1 is moving on a horizontal terrain in the proximity of aircraft. Then, when the speed of movement of the vehicle 1 passes below another speed threshold, noted V2 in the diagram (a), and which is lower than the speed V1, the control system 15 re-engages the speed which was previously engaged at the moment when the control system 15 passed to neutral because of the exceeding of the speed V 1. If the moving speed V of the vehicle 1 again exceeds the speed V1, the control system 15 returns the gearbox 11 in neutral and so on. Thus, the moving speed V of the vehicle 1 is not only limited substantially to the speed V1, but also regulated with a hysteresis H = V1 V2.

As already mentioned, the maximum authorized speed V1 in the danger zone 6 is generally between 4 and 7 km / h. The speed threshold V2 will be chosen in such a way as to obtain an appropriate control flexibility, notably in consideration of the driver's driving comfort. . From this point of view, it is preferable that the hysteresis H be less than 10% of V1, and more preferably less than 5%. But it is preferable to choose a sufficient value for the hysteresis H to avoid cycles of activation / deactivation of the gearbox 11 too fast to avoid premature aging of the latter. It is advantageous to provide that the automatic reengagement of the speed by the control system 15 when the traveling speed V of the vehicle 1 passes below V2 is only done if the rotation speed of the motor 10 is below a threshold given. This threshold will be chosen low enough to re-engage the speed under satisfactory conditions. Indeed, reengaging the speed while the rotation speed of the engine is high may have the disadvantage of causing an advance with jolts that can be detrimental to the fuselage of the aircraft in case of contact. For this, the control system 15 receives the signal, symbolized by the line 18 in FIG. 3, of a sensor for the speed of rotation of the engine 10. When the vehicle 1 leaves the danger zone 6 to enter the zone 7, the speed limitation system of the vehicle 1 goes into "docking zone" mode, as explained above with reference to Figure 2.

As mentioned, the transition to "danger zone" mode is preferably automatic, but can also be manual. For this purpose, the control system 15 receives a signal from the proximity detector or the corresponding manual activation device (not symbolized in FIG. 3) as a result of which the control system 15 will apply the "docking zone" mode. ". The operation of the speed limitation system of the "docking zone" mode may be identical to that of the "danger zone" mode described above in relation to Figure 4, except to replace the speed thresholds V1 and V2 by thresholds lower, in particular by replacing V1 by a threshold V3 which is the maximum authorized speed in the berthing zone 7. As a reminder, this is generally between 0.5 and 9 km / h. the very close proximity of the vehicle with the aircraft, it is more advantageous to apply a different operation which is detailed below with reference to FIG.

In FIG. 5, the curve of the diagram (a) illustrates the speed 'V' of displacement of the vehicle 1 in the ordinate as a function of time 't' on the abscissa while the curve of the diagram (b) gives the operating mode of the gearbox 15 on the ordinate, denoted 'BV', according to the same axis of time 't' on the abscissa as for the diagram (a). The curve of the diagram (c) gives the position of the manual speed selector 21 on the y-axis, denoted 'SV', according to the same time axis 't' on the abscissa as for diagrams (a) and (b). At the instant t = 0, the speed of the gearbox 11 is engaged, which is represented by the position marked '1' on the ordinate of the diagram (b) .The vehicle therefore moves forward with a The fact that the speed is engaged is the consequence of the fact that the control system 15 has applied it to the gearbox 11 in accordance with the selection made by the driver with the manual gear selector 21 : cf. selecting the "speed noted '1' on the diagram (c).

As illustrated, it can happen that the traveling speed V of the vehicle 1 increases and reaches the maximum speed allowed in the docking area 7, denoted V3 in the diagram (a). As in danger zone 6, the speed increase may be due to the box drag effect since the gearbox 11 includes a torque converter for the automatic disengagement of the transmission from the engine to the wheels and that the driver fails to apply the service brake to limit the speed of the vehicle 1 even though he has stopped depressing the accelerator pedal. But as soon as the traveling speed V of the vehicle 1 exceeds the maximum authorized speed V3, the control system 15 changes the reverse, denoted 'R' on the diagram (b), to the gearbox 11 instead of the move to neutral 'N' as was the case in the 'danger zone' mode. Therefore, the engine 10 will fight the movement of movement forward of the vehicle 1. The passage in reverse while the vehicle 1 is moving forward is not harmful, given the viscous coupling in the transmission kinematic chain of the motor 10 to the wheels 14 provided by the hydraulic torque converter of the gearbox 11. Then, when the speed of movement of the vehicle 1 becomes zero, the control system 15 passes the box of speed 11 in neutral: cf. 'N' on the diagram (b). As a result, the vehicle 1 remains at a standstill, which makes it possible to avoid any risk of collision of the vehicle 1 with the aircraft, for example if the exceeding of the maximum authorized travel speed is due to driver discomfort. . Once the vehicle 1 thus stopped, it is particularly advantageous to provide that it can not restart just because the driver presses the accelerator pedal of the vehicle 1 because it could happen accidentally in case of discomfort of the driver or also in case of inattention of it. For this, the control system 15 can advantageously be provided to keep the gearbox in neutral until the gear selector 21 has been placed in neutral - cf. 'N'on the diagram (c). The control system 15 causes the gearbox 11 to recommit the speed newly selected by the speed selector 21 cf instant t2 in FIG. 5 after it has been placed in the neutral position - cf. 5. In the "docking zone" mode previously described, a variant may consist in not applying the braking of the vehicle 1 by reversing the direction of transmission of the gearbox 11 until the the speed of movement of the vehicle 1 is zero, but until it is reduced below an acceptable threshold, lower than the maximum authorized speed V3. More generally, it is advantageous for the gearbox 11 to be electrically controlled, which makes it possible to implement the speed limitation method simply and effectively by means of an electronic control system, for example an automaton. programmable, electrically controlling the gearbox 11. Of course, the present invention is not limited to the examples and the embodiment described and shown, but it is capable of many variants accessible to those skilled in the art.

Claims (14)

REVENDICATIONS1. A method of limiting the traveling speed of a motor vehicle, preferably an airport vehicle, which vehicle comprises a traction engine and a gearbox for transmitting the rotation of the engine to the wheels of the vehicle, the method comprising a step a ) of automatically switching the gearbox to neutral when the speed of movement of the vehicle exceeds a first threshold. The method of claim 1, further comprising a step b) after step a), wherein step b) automatically recommitting the transmission of the rotation of the engine to the wheels by the gearbox when the traveling speed. vehicle passes below a second threshold below the first threshold. 3. A method according to claim 2, wherein, in step b), the automatic reengagement of the transmission is operated by passing again the speed that was selected when the gearbox was automatically passed to dead point in step a). The method of claim 2 or 3, wherein step b) is performed provided that the rotational speed of the engine is below a given threshold. 4. The method of claim 1, wherein step a) comprises the following successive substeps: al) automatically reverse the direction of travel on the gearbox when the speed of movement of the vehicle exceeds the first threshold; and a2) automatically shifting the gearbox to neutral when the vehicle traveling speed falls below a second threshold lower than the first threshold. 5. The method of claim 5 implemented to stop the vehicle, wherein, in the sub-step a2), the passage of the gearbox in neutral is operated when the speed of movement of the vehicle is zero. The method of claim 5 or 6, wherein step a2) further comprises inhibiting reengagement of a speed by the gearbox (11) as long as 7. the manual gear selector (21) of the gearbox has not been previously manually moved into neutral. 8. A method according to any one of claims 1 to 7 wherein it ensures the transmission by the gearbox of the rotation of the engine to the wheels of the vehicle through a hydraulic torque converter ensuring automatic disengagement of the box automatic. Airport vehicle, comprising: - a heat engine (10) for traction of the vehicle; wheels (14) supporting the vehicle; - a gearbox (11) transmitting the rotation of the engine to the wheels supporting the vehicle; - a control system (15) of the gearbox (11); a sensor for measuring the speed of movement of the vehicle, which sensor is connected to the control system (15) of the gearbox (11); wherein the control system is arranged to apply the method according to any one of claims 1 to 8. 10. Vehicle according to claim 9, wherein the gearbox (11) comprises an automatic hydraulic clutch torque converter. Airport vehicle according to claim 9 or 10, wherein the control system (15) of the gearbox is provided for selectively applying a first mode of operation and a second mode of operation, wherein: - the first mode method of operation is to apply the method according to any one of claims 2 to 4 wherein the first threshold is set to a first predetermined value (V1); and the second mode of operation comprises applying the method according to any one of claims 5 to 7 wherein the first threshold is set to a second predetermined value (V3) less than the first predetermined value (V1). 35 12. Vehicle according to claim 11, wherein the first predetermined value (V1) is between 4 and 7 km / h and the second predetermined value (V3) is between 0.5 and 0.9 km / h. Vehicle according to claim 11 or 12, comprising a proximity sensor (14) of the vehicle with an aircraft, wherein the control system (15) of the gearbox applies the second mode of operation when the proximity of the vehicle with an aircraft is detected by the proximity detector. A vehicle according to claim 13, wherein the proximity detector (14) comprises a three-dimensional vision device with shape and object recognition, the predetermined parameters including at least one operating state diagnostic of the vision device.