CONTROL SYSTEM FOR CONTROLLING A LANDING GEAR DRIVE SYSTEM

Abstract

A control system for controlling a landing gear drive system for driving rotation of an aircraft wheel is disclosed having a control panel with a controller having a forward motion setting and a zero speed setting, a control unit for receiving a control input from the controller, and for providing a torque command to be applied to the wheel, and a speed sensor for sensing an aircraft taxi speed and for providing an indication of the aircraft taxi speed to the control unit. When the controller is moved from the forward motion setting to the zero speed setting, the control unit provides a torque command to the drive system to provide zero forwards driving torque to the wheel, and a braking command to apply a braking torque to the wheel.

Claims

1. A control system for controlling a landing gear drive system on an aircraft, the drive system being capable of driving rotation of a wheel of the aircraft, the control system comprising: a control panel, provided with a controller, the controller having at least two settings: i) a forward motion setting, and ii) a zero speed setting, a control unit for receiving a control input from the controller, and for providing a torque command to be applied to the wheel, and a speed sensor for sensing an aircraft taxi speed and for providing an indication of the aircraft taxi speed to the control unit, wherein the control unit is arranged such that, when the controller is moved from the forward motion setting to the zero speed setting: a) the control unit provides a torque command to the drive system to provide zero forwards driving torque to the wheel, and b) the control unit provides a braking command to apply a braking torque to the wheel to slow rotation of the wheel while the aircraft taxi speed is above zero.

2. A control system as claimed in claim 1, wherein the drive system comprises a pinion gear driveable by a motor, the pinion gear being arrangeable to drive rotation of the wheel, and wherein the torque command to provide zero forwards driving torque to the wheel includes a command to reduce the driving torque provided by the motor to the pinion gear to zero.

3. A control system as claimed in claim 2, wherein the command to reduce the driving torque provided by the motor to the pinion gear to zero is given when the indication of the aircraft taxi speed is below a predetermined lowness threshold.

4. A control system as claimed in claim 1, wherein the braking command to apply a braking torque to the wheel to slow rotation of the wheel includes a command to a braking system of the aircraft to apply a braking torque to the wheel.

5. A control system as claimed in claim 4, wherein the command to the braking system of the aircraft is given when the indication of the aircraft taxi speed is low.

6. A control system as claimed in claim 1, wherein the braking command to apply a braking torque to the wheel to slow rotation of the wheel includes a command to the drive system of the aircraft to apply a braking torque to the wheel, wherein the drive system is commanded to provide a regenerative braking torque.

7. A control system as claimed in claim 6, wherein the command to the drive system of the aircraft is given when the indication of the aircraft taxi speed is low.

8. A control system for controlling a landing gear drive system on an aircraft, the drive system being capable of driving rotation of a wheel of the aircraft, the control system comprising: a control panel, provided with a controller, the controller having at least two forward motion settings: i) a low forward speed setting, and ii) a high forward speed setting, a control unit for receiving a control input from the controller, and for providing a torque command to be applied to the wheel, and a speed sensor for sensing an aircraft taxi speed and for providing an indication of the aircraft taxi speed to the control unit, wherein the control unit is arranged such that, when the controller is in the low forward speed setting, the control unit provides a torque command to the drive system, based on the indication of the aircraft taxi speed, to maintain the aircraft taxi speed at or near a desired speed.

9. A control system as claimed in claim 8, wherein the desired speed is within the range between 1 and 3 knots, preferably 1.5 to 2.5 knots and more preferably 1.75 to 2.25 knots.

10. A control system for controlling a landing gear drive system on an aircraft, the drive system being capable of driving rotation of a wheel of the aircraft, the control system comprising: a control panel, provided with a controller, the controller having at least two power settings: i) a normal power setting, and ii) a boost power setting, and a control unit for receiving a control input from the controller, and for providing a torque command to be applied to the wheel, wherein the control unit is arranged such that, when the controller is in the normal power setting, the control unit provides a torque command to the drive system to provide a driving torque to the wheel up to a first power level, and wherein the control unit is arranged such that, when the controller is in the boost power setting, the control unit provides a torque command to the drive system to provide a driving torque to the wheel at a second power level, higher than the first power level, and wherein the controller is biased away from the boost power setting and towards the normal power setting.

11. A control system as claimed in claim 10, wherein the control unit is arranged to reduce the torque command to the first power level, if the controller is in the boost power setting and if an indication of the additional power provided to the drive system in the boost power setting has reached a set limit.

12. A control system for controlling a landing gear drive system on an aircraft, the drive system being capable of driving rotation of a wheel of the aircraft, the control system comprising: a control panel, provided with a controller, the controller having a backwards motion setting, a control unit for receiving a control input from the controller, and for providing a torque command to be applied to the wheel, and a speed sensor for sensing an aircraft taxi speed and for providing an indication of the aircraft taxi speed to the control unit, wherein the control unit is arranged such that, when the controller is in the backwards motion setting, the control unit provides a backwards driving torque command to the drive system, based on the indication of the aircraft taxi speed, to maintain the backwards aircraft taxi speed at or near a desired speed.

13. A control system as claimed in claim 12, wherein the desired speed is within the range between 1 and 3 knots, preferably 1.5 to 2.5 knots and more preferably 1.75 to 2.25 knots.

14. A control system for controlling a landing gear drive system on an aircraft, the drive system being capable of driving rotation of a wheel of the aircraft, the control system comprising: a control panel, provided with a controller, the controller having at least two settings: i) a backwards motion setting, and ii) a zero speed setting, a control unit for receiving a control input from the controller, and for providing a torque command to be applied to the wheel, and a speed sensor for sensing an aircraft taxi speed and for providing an indication of the aircraft taxi speed to the control unit, wherein the control unit is arranged such that, when the controller is moved from the backwards motion setting to the zero speed setting: a) the control unit provides a torque command to the drive system to provide zero backwards driving torque to the wheel, and b) the control unit provides a braking command to apply a braking torque to the wheel to slow rotation of the wheel while the aircraft taxi speed is above zero.

15. A control system as claimed in claim 14, wherein the drive system comprises a pinion gear driveable by a motor, the pinion gear being arrangeable to drive rotation of the wheel, and wherein the torque command to provide zero backwards driving torque to the wheel includes a command to reduce the backwards driving torque provided by the motor to the pinion gear to zero.

16. A control system as claimed in claim 14, wherein the braking command to apply a braking torque to the wheel to slow rotation of the wheel includes a command to a braking system of the aircraft to apply a braking torque to the wheel.

17. A control system as claimed in claim 14, wherein the braking command to apply a braking torque to the wheel to slow rotation of the wheel includes a command to the drive system of the aircraft to apply a braking torque to the wheel, wherein the drive system is commanded to provide a regenerative braking torque.

18. An aircraft comprising an aircraft landing gear, having at least one wheel provided with a drive system for driving rotation of the wheel, the drive system comprising a motor, wherein the aircraft also comprises the control system of claim 1, the control system or control panel being arranged to control the drive system.

19. A method of controlling an aircraft landing gear drive system capable of driving rotation of a wheel of an aircraft, the method comprising the step of using a control system of claim 1.

20. A control panel of an aircraft, the control panel provided with a controller in the form of a rotary dial and having a forward motion setting for controlling forwards driving rotation of a wheel of the aircraft, wherein the forward motion setting is located at least partially between 9 o'clock and 12 o'clock on the rotary dial.

Description

DESCRIPTION OF THE DRAWINGS

[0129] Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:

[0130] FIG. 1 shows a front schematic view of an example controller;

[0131] FIG. 2a shows a front schematic view of a controller according to a first embodiment of the invention;

[0132] FIG. 2b shows a front schematic view of the controller of FIG. 2a, also showing a dial switch;

[0133] FIG. 3 shows a schematic diagram of a control system including the controller of FIGS. 2a and 2b;

[0134] FIG. 4 shows a schematic diagram of a controller according to a second embodiment of the invention; and

[0135] FIG. 5 shows a front view of an aircraft including the control system of FIG. 3.

DETAILED DESCRIPTION

[0136] FIG. 1 shows a front schematic view of an example controller 10, as described above.

[0137] FIG. 2a shows a front schematic view of a controller 20 according to a first embodiment of the invention.

[0138] In a similar way to the controller 10 of FIG. 1, the controller 20 has a backwards speed setting 21 and a (normal power) forward speed setting region 23. When in the forward speed setting region 23, the system provides an amount of torque to the drive system based on the position of a controller within the forward speed setting region 23. In other words, the controller 20 dictates how much torque is provided.

[0139] Also similar to FIG. 1, in the backwards speed setting 21, the amount of backwards driving torque supplied (and regenerative braking) is based on the speed of the aircraft, such that the speed is maintained to be at or near 2 knots (backwards). This enables the aircraft to be taxied at a speed similar to walking speed, without a pilot, for example, having to actively manage the backwards speed.

[0140] When the controller is moved from the backwards speed setting to a zero speed setting 27, the torque supplied is adjusted, and brakes applied, so as to slow the aircraft down to zero speed.

[0141] The controller has a maximum normal power setting 24. This is the maximum setting at which torque at that level can be continuously supplied. This is 55 kVA.

[0142] However, the controller 20 can be placed in a (forwards) boost power setting 30. In this setting, an additional torque level is available, of 18% more (65 kVA as opposed to 55 kVA). A spring (shown by arrow 31) biases the controller back to the maximum normal power setting 24.

[0143] The additional torque level is only available for a limited time, in this embodiment, for 1 minute. After that, the torque level provided is at the same level as for the maximum normal power setting 24, even if the controller is held, for example by the pilot, against the spring 31, in the boost power setting 30.

[0144] The additional power in the boost power setting is provided by the same power source that supplies the power of the normal power setting. This is from an APU (Auxiliary Power Unit) (not shown).

[0145] The additional torque can be used, temporarily, for example if the aircraft is going uphill or crossing a runway. This enables the aircraft to be effectively driven at a suitable speed, but does not generally overburden a power source of the landing gear drive system, or affect the health of the power source equipment.

[0146] There is also a (normal power) low forwards speed setting 28. In this setting, the amount of forwards driving torque supplied (by a landing gear drive system), and the amount of regenerative braking, is based on the speed of the aircraft (sensed by a sensor), such that the speed is maintained to be at or near 2 knots (forwards). This enables the aircraft to be taxied at a speed similar to walking speed, without a pilot, for example, having to actively manage the forwards speed. This makes parking the aircraft (nose in) at an aircraft gate much easier and will likely prevent damage/risk from a low speed impact occurring between an aircraft and an aircraft gate.

[0147] When the controller 20 is moved from the low forwards speed setting 28 to the zero speed setting 27, the driving torque supplied is adjusted (for example by reducing the forwards driving torque to zero, by reducing the torque supplied to the drive system or by disengaging the drive system from an aircraft wheel), and brakes may be applied, so as to slow the aircraft down to zero speed.

[0148] Hence, when the controller 20 is moved from the backwards speed setting 21 or low forwards speed setting 28 to the zero speed setting 27, the aircraft is actively slowed to have zero speed. Hence, the zero speed setting 27 always acts as a supplement to a park brake system of the aircraft.

[0149] FIG. 2b shows a front schematic view of the controller 200 of FIG. 2a, also showing a dial switch 32.

[0150] It is this dial switch 32 that is rotated into and out of the different settings 21, 27, 28, 23, 24, 30.

[0151] FIG. 3 shows a schematic diagram of a control system 200 including the controller 20 of FIGS. 2a and 2b.

[0152] The controller 20 is part of a control panel 40. The control panel 40 has a control signal line 41 to a control unit 60. This is how the setting of the controller 20 is sent to the control unit 60.

[0153] There is also an aircraft speed sensor 50 that has a speed indication signal line 51 to the control unit 60. This is how the control unit has an indication of the aircraft taxi speed, during use.

[0154] The control unit 60 includes a computer to calculate and provide two outputs; an output command for the landing gear drive system and an output command for the friction brake system.

[0155] The output command for the drive system is provided to the drive system (represented by box 72) by the drive system command line 71. This may be a disengagement command, a re-engagement command, a regenerating braking torque command (i.e. a command for the drive system to remain engaged with no driving torque provided), a forwards driving torque command or a backwards driving torque command.

[0156] The output command for the friction brake system is provided to the brake system (represented by box 82) by the brake system command line 81. This is a braking torque command.

[0157] The drive system 72 (not shown in detail) comprises a drive system similar to as shown in GB 2528966 A. It has a drive pinion driven by a torque controlled motor and a driven gear attached to a wheel of the aircraft. The drive pinion can be selectively moved in and out of meshing engagement with the driven gear. It is this engagement that is controlled by the disengagement and re-engagement commands, for example.

[0158] The control unit 60 is provided with two sets of input values.

[0159] Firstly, a speed threshold set of values (Vt) represented by box 61. In this example, this is just one speed value. Above this threshold taxi speed value (here, 30 knots), the control unit will command the drive system to disengage the pinion gear and driven gear (disengagement command), as will be described below. Below this threshold taxi speed value, the control unit will command the drive system to remain engaged, as will be described below.

[0160] Secondly, a set of target speed values, represented by box 62. Here, these are a low forwards speed setting of 2 knots and a backwards speed setting of 2 knots. In other words, these are the desired aircraft taxi speeds in settings 28 and 21 respectively.

[0161] FIG. 5 shows a front view of an aircraft 2000 including the control system 200 of FIG. 3.

[0162] The aircraft 2000 is provided with a nose landing gear 2100 with two wheels 2101, 2102. The aircraft also has a right hand (viewed from the forwards direction of the aircraft) landing gear 2200 with two wheels 2201, 2202. The aircraft also has a left hand landing gear 2300 with two wheels 2301, 2302.

[0163] The aircraft 2000 is also provided with the control system 200 described above (not shown in FIG. 5), a drive system 72 (not shown in FIG. 5) for driving one or more main landing gear wheels 2201, 2202, 2301, 2302 and a braking system 82 (not shown in FIG. 5).

[0164] In use, a pilot uses the controller 20 to adjust the taxi speed of the aircraft 2000, through use of the drive system 72 and brake system 82. The required commands of the drive system 72 and brake system 82 are decided by the control unit 60, based on the controller 20 setting (from signal line 41) and the aircraft taxi speed (from line 51).

[0165] For example, when the controller 20 is in the backwards speed setting 21, the control unit 60 commands the drive system 72 provide a backwards driving torque, and regenerative braking, to achieve the target speed (here, 2 knots backwards) provided in box 62. This is done as a feedback loop, based on the taxi speed detected by the aircraft speed sensor 50.

[0166] When the controller 20 is moved to the zero speed setting 27, the control unit 60 commands the drive system to stop providing a backwards driving torque. In addition, the control unit 60 will command the friction brake system 82 to apply the friction brakes to apply a braking torque to reduce the backwards speed of the aircraft to zero.

[0167] When the controller 20 is moved to the low forwards speed setting 28, the control unit 60 will command the drive system 72 to apply a forwards driving torque, and provide regenerative braking. This will be done to achieve the target speed (here, 2 knots forwards) provided in box 62. This is done as a feedback loop, based on the taxi speed detected by the aircraft speed sensor 50.

[0168] When the controller 20 is then moved into the high forwards speed region 23, the torque commanded from the drive system 72 is not related or constrained by the aircraft speed. Instead, the drive system 72 is commanded to provide a torque level corresponding to the relative position of the controller dial 32 within the region 23. For example, if the dial 32 is only just above the low speed setting 28, the torque demanded will be low (but generally enough to provide an aircraft speed of more than 2 knots). If the dial 32 is just below the maximum normal power setting 24, the torque demanded will be high (almost at the maximum normal torque available).

[0169] If the pilot wishes to increase the torque demanded further, they may actively apply pressure to the dial switch 32 against the spring 31 to hold the dial switch in the boost power setting 30. If the pilot releases the dial switch 32 it will be urged back (by the spring 31) to the maximum normal power setting 24. The boost power setting 30 is able to provide 18% more power than in the maximum normal power setting 24.

[0170] When the dial switch 32 is in the boost power setting 30, the torque demanded corresponds to the boost power setting (65 kVA).

[0171] However, if the dial switch 32 has been in the boost power setting for 1 minute (60 seconds), the torque demanded from the drive system 72 will be reduced to that of the maximum normal power level 24 by the control unit 60. This can then be re-increased after 1 minute (60 seconds) has passed.

[0172] When the controller 20 is moved from a relatively higher speed setting to a relatively lower speed setting in region 23, the control unit commands that the drive system 72 provides an appropriate lower torque, based on the position of the dial within the region 23. No friction braking command is given and so the aircraft slows naturally, or with manual braking by the pilot.

[0173] When the controller 20 is moved to the low speed setting 28, from a setting in the high forwards speed setting region 23 (or boost power setting 30), the control unit 60 commands the drive system 72 and the brake system 82 such that the aircraft reduces speed to, and then maintains the target speed, of 2 knots.

[0174] Initially, if the aircraft speed is below 3 knots, for example, the brake system 82 will be commanded to provide a braking torque to reduce the aircraft speed.

[0175] Once the aircraft speed has reduced to 2 knots, the drive system 72 provides a driving torque and a regenerative braking torque to maintain the aircraft speed at 2 knots.

[0176] If the initial aircraft speed is above 3 knots, for example, the pilot may have to actively use the brake pedals to reduce the aircraft speed to 3 knots. After this, the brake system 82 will be commanded to provide a braking torque to reduce the aircraft speed further.

[0177] When the controller 20 is moved to the zero speed setting 27 from the low forwards speed setting 28, the control unit 60 commands such that the aircraft speed reduces to zero.

[0178] The brake system 82 is commanded to provide a friction braking torque to do so.

[0179] FIG. 4 shows a schematic diagram of a controller 20′, on a control panel 40′, according to a second embodiment of the invention. The controller 20′, and its use, is similar to that described for controller 20. However, the differences, in relation to the setting positions, will be described.

[0180] Here, the dial switch 32′ has the different settings arranged at different angles about the dial. The maximum normal power setting 24′ is located at “12 o'clock” on the dial. The boost power setting 30′ is located 25 degrees further round (clockwise). The low forward speed setting 28′ is located at 90 degrees anti-clockwise (i.e. at “9 o'clock”) from the maximum normal power setting 24′. The zero speed setting 27′ is located 20 degrees further anti-clockwise (i.e. 110 degrees anti-clockwise from the maximum normal power setting 24′). Finally, the backward speed setting 21′ is located 25 degrees further anti-clockwise (i.e. 135 degrees anti-clockwise from the maximum normal power setting 24′).

[0181] These setting positions provide that substantially all of the forward settings are in a forward facing position (i.e. between “9 o'clock” and “3 o'clock” on the dial) and that, for most scenarios, moving to a greater forward speed (e.g. within the region 23′) involves movement of the dial to a more forward position (i.e. moving from 9 o'clock” to 12 o'clock”).

[0182] Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described.

[0183] The reduction of torque level to that of the maximum normal power setting 24 may occur after a different length of time, for example 30 seconds or 90 seconds. The reduction may instead occur when a certain amount of additional torque has been employed.

[0184] The re-increase of torque level to that of the boost power setting 30 may occur after a different length of time, for example 30 seconds or 90 seconds. The re-increase may instead occur when a certain amount of reduction is torque has been achieved. For example, it may be equivalent to when the torque provided has been at a mid-power level (half way in region 23) for 30 seconds or at the maximum power level 24 for 1 minute.

[0185] The re-increase and/or cutting off of boost power level may be based on the overall power consumption/demand of the drive system over a period of time, for example, the previous 2 or 3 minutes.

[0186] The additional torque level associated with the boost power setting 30 may instead be provided by a different power source from that which supplies the power of the normal power setting. For example, this may be by a battery, if the normal torque is provided by an APU.

[0187] The normal torque level may be provided by one or more power sources, other than an APU, for example a battery. Here, if the additional torque level is provided by a different power source, it may be from an APU.

[0188] When the controller 20 is moved so as to reduce the aircraft speed (i.e. from a forwards speed setting to a lower speed setting or the zero speed setting 27), a regenerative braking torque may be provided by the landing gear drive system so as to slow the aircraft down to zero speed, or a braking torque from a brake system of the aircraft may be provided, or both.

[0189] Different braking methods may be employed at different aircraft speeds.

[0190] For example, at a low speed (e.g. under 2 knots) friction braking and regenerative braking may be commanded.

[0191] The speed threshold(s) may be any suitable, appropriate speed, chosen to prevent appropriate damage to the drive system. They may be variable, provided to the control unit 60 by a further input.

[0192] The target speed values (low forwards speed setting and backwards speed setting) may be any suitable, appropriate speed, for example 1 knot, 1.5 knots, 2.5 knots, 3 knots etc. They may be variable, provided to the control unit 60 by a further input.

[0193] The brake system of the aircraft may also or instead of friction brakes, include other braking means.

[0194] Any suitable drive system may be used.

[0195] The drive system may drive any number of wheels of the aircraft, including one or more of nose or main landing gear wheels.

[0196] Any suitable controller may be used. If a dial switch 32 like described here is used, any suitable angles may be used for the different settings.

[0197] The control system 200 may not include the brake system and instead, the pilot may command the brake system directly from brake pedals, or other controls, in the cockpit, for example.

[0198] As a further alternative, the command to the brake system 82 may come via the drive system 72 (i.e. not directly from the control unit 60).

[0199] Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

[0200] It should be noted that throughout this specification, “or” should be interpreted as “and/or”.