Braking system for a dual-landing gear aircraft, aircraft and method for braking an aircraft

Abstract

A braking system for a dual landing gear aircraft, an aircraft and a method for braking an aircraft. The braking system pairs an outboard brake control into an outboard brake system control unit (BSCU) and pairs an inboard brake control into a second inboard brake system control unit (BSCU). Each BSCU is designed with two independent control channels, in which the front wheel set is paired in one control channel and the rear wheels are paired on the other control channel. Backup braking is provided via a backup brake module installed in the front and rear wheel pairings.

Description

Technical Field

[0001] The present disclosure relates generally to aircraft braking systems and, more particularly, to a brake pairing scheme for a dual landing gear aircraft that creates a direct and robust braking system. Background Art

[0002] The aircraft may include a dual landing gear structure including a plurality of wheel sets. Each wheel set includes a plurality of wheels arranged as two or more inner wheels and two or more outer wheels. The wheels are further arranged as a front wheel set closer to the front of the aircraft and a rear wheel set towards the rear of the aircraft.

[0003] Conventional braking systems divide the aircraft into a left braking system and a right braking system. Failures in these conventional systems result in an asymmetric loss of brakes with the brakes only applying along one side of the aircraft. This results in increased pilot workload and may also hinder subsequent dispatch of the aircraft. These conventional systems also typically include complex and expensive redundancy and monitoring systems.

[0004] Therefore, there is a need for an aircraft braking system that reduces and / or prevents asymmetric loss of braking. Summary of the invention

[0005] The present application is directed to a braking system for an aircraft. The braking system is configured to provide symmetrical braking of the wheels of the aircraft.

[0006] One aspect is directed to a braking system for a dual-landing gear aircraft, the dual-landing gear aircraft including a left landing gear and a right landing gear, the left landing gear and the right landing gear each having a front inner wheel and a rear inner wheel and a front outer wheel and a rear outer wheel. The braking system includes an outer brake system control unit, the outer brake system control unit having at least a first processing circuit, the first processing circuit generating a brake control signal in response to a pilot input to symmetrically control the braking of a first wheel pair including only the front outer wheel and a second wheel pair including only the rear outer wheel. The inner brake system control unit includes at least a second processing circuit, the second processing circuit generating a brake control signal in response to the pilot input to symmetrically control the braking of a third wheel pair including only the front inner wheel and a fourth wheel pair including only the rear inner wheel. The inner brake system control unit is independent of the outer brake system control unit. A hydraulic system applies a braking force to the wheels in response to the brake control signal.

[0007] In one aspect, the outboard brake system control unit sends the brake control signal along a first control lane to brake only the front outboard wheels of both the left landing gear and the right landing gear, and sends the brake control signal along a second control lane to brake only the rear outboard wheels of both the left landing gear and the right landing gear, and the first control lane is independent of the second control lane.

[0008] In one aspect, the inner brake system control unit sends the brake control signal along a third control channel to brake only the front inner wheels of both the left landing gear and the right landing gear, and sends the brake control signal along a fourth control channel to brake only the rear inner wheels of both the left landing gear and the right landing gear, and the third control channel is independent of the fourth control channel.

[0009] In one aspect, the inboard brake system control unit and the outboard brake system control unit further include an input interface configured to receive the pilot input, and the pilot input includes separate first and second inputs.

[0010] In one aspect, the hydraulic system includes: a first hydraulic line and a backup line, the first hydraulic line and the backup line supplying hydraulic fluid to the brakes at the wheels; a servo valve positioned along the first hydraulic line and the backup line, the servo valve regulating the pressure of the hydraulic fluid supplied to the brakes in response to the brake control signals received from the first brake system control unit and the second brake system control unit; a shuttle valve operatively connecting the first hydraulic line and the backup line, and the shuttle valve being configured to supply hydraulic fluid from one of the first hydraulic line and the backup line.

[0011] In one aspect, each of the servovalves located along the first hydraulic line regulates pressure to one of the brakes, and the servovalves located along the backup supply line regulate a pair of the brakes on one of the left and right landing gears.

[0012] In one aspect, a first module houses each servo valve that regulates the pressure of hydraulic fluid along the first hydraulic line to a brake of one of the left and right landing gears, and a second module houses each servo valve that regulates the pressure of hydraulic fluid along the second hydraulic line to a brake of the other of the left and right landing gears.

[0013] In one aspect, each of the first module and the second module includes a shutoff valve to reduce leakage of hydraulic fluid.

[0014] In one aspect, the outer brake system control unit controls a servo valve that supplies hydraulic fluid to each of the front outer wheel and the rear outer wheel, and the inner brake system control unit controls a servo valve that supplies hydraulic fluid to each of the front inner wheel and the rear inner wheel.

[0015] One aspect is directed to an aircraft having a braking system, the braking system comprising an outboard braking system control unit having at least a first processing circuit, the first processing circuit generating a braking control signal in response to a pilot input to symmetrically control braking of a first wheel pair including only the front outboard wheel and a second wheel pair including only the rear outboard wheel. The braking system comprises an inboard braking system control unit including at least a second processing circuit, the second processing circuit generating a braking control signal in response to the pilot input to symmetrically control braking of a third wheel pair including only the front inboard wheel and a fourth wheel pair including only the rear inboard wheel. The inboard braking system control unit is independent of the outboard braking system control unit. The braking system comprises a hydraulic system to apply braking forces to the wheels in response to the braking control signals.

[0016] One aspect is directed to providing a braking system for a dual-landing gear aircraft having a left landing gear and a right landing gear, each of which has a front inner wheel and a rear inner wheel and a front outer wheel and a rear outer wheel. The braking system includes a hydraulic system having a plurality of supply lines, each of which supplies hydraulic fluid to control the braking of one of the wheels. Each of the supply lines includes a plurality of valves and a brake for applying a braking force to one of the wheels. The braking system includes an outer brake system control unit having a first processing circuit that generates a brake control signal in response to a pilot input to control a valve of a first wheel pair having only the front outer wheel and a valve of a second wheel pair having only the rear outer wheel. The inner brake system control unit includes a second processing circuit that generates a brake control signal to control a valve of a third wheel pair having only the front inner wheel and a valve of a fourth wheel pair having only the rear inner wheel. The outboard brake system control unit and the inboard brake system control unit receive pilot input and control valves of each of the wheelsets to apply symmetrical braking forces to the wheels of each of the wheelsets.

[0017] In one aspect, a first control channel extends between the outer brake system control unit and one of the valves on one of the supply lines for the front outer wheel, a second control channel extends between the outer brake system control unit and one of the valves on one of the supply lines for the rear outer wheel, a third control channel extends between the inner brake system control unit and one of the valves on one of the supply lines for the front inner wheel, and a fourth control channel extends between the inner brake system control unit and one of the valves on one of the supply lines for the rear inner wheel, and each of the control channels is independent of one another.

[0018] In one aspect, the hydraulic system includes a first hydraulic supply line and a backup hydraulic supply line, and each of the supply lines further includes a shuttle valve that selectively delivers the hydraulic fluid from one of the first hydraulic supply line and the backup hydraulic supply line to the brake based on the pilot input.

[0019] In one aspect, each of the inboard brake system control unit and the outboard brake system control unit receives pilot input from both the first pilot and the second pilot.

[0020] One aspect is directed to a method of braking an aircraft. The method includes the steps of receiving pilot input at both an outboard brake system control unit and an inboard brake system control unit. The method includes the steps of sending a first braking signal from the outboard brake system control unit based on the pilot input and symmetrically braking a first pair of front outboard wheels of a right landing gear and a left landing gear and a second pair of rear outboard wheels on the right landing gear and the left landing gear. The method includes the steps of sending a second braking signal from the inboard brake system control unit based on the pilot input and symmetrically braking a third pair of rear inboard wheels of the right landing gear and the left landing gear and a fourth pair of rear inboard wheels on the right landing gear and the left landing gear.

[0021] In one aspect, the method comprises the steps of sending the first braking signal from the outboard brake system control unit to the first pair of front outboard wheels via a first control channel, and sending the first braking signal from the outboard brake system control unit to the second pair of rear outboard wheels via an independent second control channel.

[0022] In one aspect, the method includes the steps of sending the second braking signal from the inner brake system control unit to the third pair of front inner wheels via a third control channel, and sending the second braking signal from the inner brake system control unit to the fourth pair of rear inner wheels via an independent fourth control channel.

[0023] In one aspect, the method includes the steps of determining a larger input of a first input and a second input based on the pilot input, and based on the larger input of the first input and the second input, sending the first braking signal from the outer brake system control unit to symmetrically brake the first pair of outer wheels and the second pair of outer wheels, and based on the larger input of the first input and the second input, sending the second braking signal from the inner brake system control unit to symmetrically brake the third pair of inner wheels and the fourth pair of inner wheels.

[0024] In one aspect, the method includes the steps of determining a smaller of the braking commands between the front and rear wheel pairs based on pilot input, and controlling backup braking based on the smaller of the braking commands between the front and rear wheel pairs.

[0025] In one aspect, the method includes the steps of sending the braking signal to a servo valve and regulating the flow of hydraulic fluid to regulate the braking of the plurality of pairs of brakes. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of the braking system.

[0027] Figure 2 is a schematic diagram of a twin landing gear having a pair of wheelsets on opposite sides of a longitudinal axis.

[0028] Figure 3 is a schematic diagram of the braking system that receives pedal input and controls the braking of the wheels on the landing gear.

[0029] Figure 4 is a schematic diagram of one of the inner brake system control unit and the outer brake system control unit.

[0030] Figure 5 is a schematic diagram for generating brake commands in the brake system control unit.

[0031] Figure 6 It is a schematic diagram of the hydraulic system.

[0032] Figure 7 is a flow chart of a method for braking an aircraft. DETAILED DESCRIPTION

[0033] The present application is directed to a braking system for use with a dual landing gear aircraft. The braking system pairs the outboard brake control into an outboard brake system control unit (BSCU) and pairs the inboard brake control into a second inboard brake system control unit (BSCU). Each BSCU is designed with two independent control channels, in which the front wheel set is paired in one control channel and the rear wheels are paired on the other control channel. Locking wheel and watercraft protection are provided by communication between control channels within a given BSCU. Backup braking is provided via a backup brake module installed in a front and rear wheel pairing manner and is commanded via a controlled channel shared with each BSCU. This architecture optimally incorporates the preferred inboard / outboard architecture while keeping the control valve close to the brake.

[0034] Each BSCU receives brake control signals from the pedals from the first pilot and the second pilot. The BSCU logic is such that the larger of the first pilot command and the second pilot command is selected when a pressure below the slip pressure of the tire is applied to the brake. In the case of a pressure above the slip pressure of the tire, the brake command is generated via the anti-skid function. The backup brake control command is generated using the smaller of the brake commands between the front wheel pair and the rear wheel pair.

[0035] Figure 1 is a schematic representation of a braking system 10 for an aircraft having a pair of wheelsets 60. The braking system 10 includes an outboard BSCU 20 and an inboard BSCU 30. Each of the outboard BSCU 20 and the inboard BSCU 30 receives input from a pilot's brake pedal 65. The outboard BSCU 20 and the inboard BSCU 30 independently generate brake actuator control signals and apply the brake actuator control signals to the hydraulic system 40 to independently control the brakes on the wheels 69 of the wheelsets 60 of the aircraft.

[0036] The braking system 10 is configured for use with an aircraft having a landing gear having a dual wheel set 60, such as Figure 2 As shown. The wheel groups 60 can be positioned on opposite sides (i.e., right and left sides) of the longitudinal centerline C of the aircraft. Additionally or alternatively, the wheel groups 60 can be positioned on the same side of the longitudinal centerline C. Each wheel group 60 is depicted in a two-dimensional array having a row 61 including two or more front wheels 69 and a row 62 including two or more rear wheels 69. The wheel groups 60 are also aligned to include an inner row 63 having two or more wheels 69, which is closer to the centerline C than the outer row 64 that is further away from the centerline C. The wheel groups 60 can include a variety of arrangement architectures, including but not limited to one or more rows of three or more wheels 69.

[0037] Figure 3 1 illustrates a more detailed schematic representation of the braking system 10 within the context of an aircraft. The braking system 10 is positioned to receive signals from the pilot's brake pedal 65 and control the braking of the wheels 69 of the wheelset 60. The outboard BSCU 20 and the inboard BSCU 30 receive input from the pilot's brake pedal 65. Figure 3 As shown, a pedal input from a first pilot's brake pedal 65 is received by the outboard BSCU 20. A pedal input from a second pilot's brake pedal 65 is received by the inboard BSCU 30. Additionally or alternatively, the BSCUs 20, 30 may receive different pedal inputs, such as each BSCU 20, 30 receiving one input from each pilot (e.g., the BSCU 20 receives right pedal inputs from both pilots, and the BSCU 30 receives left pedal inputs from both pilots).

[0038] Each of the outer BSCU 20 and the inner BSCU 30 directly receives the first signal and indirectly receives the second signal through the other BSCU 20, 30. Figure 3 As shown, each pilot is provided with two brake pedals 65, such as a left brake pedal 65 and a right brake pedal 65. The pilot pedals 65 may include a first pair of pedals 65 provided for a first pilot (e.g., captain) and a second pair of pedals 65 provided for a second pilot (e.g., co-pilot). The pilot physically manipulates the pedals 65 to generate pilot pedal physical inputs. The physical inputs of both the first pilot pedal 65 and the second pilot pedal 65 are measured from their natural positions by sensors or equivalent components, and the physical inputs are converted into first pilot command control signals and second pilot command control signals by transducers or equivalent components. The signal from the first pilot brake pedal 65 is received at the outer BSCU 20, and the signal from the second pilot brake pedal 65 is received at the inner BSCU 30.

[0039] The inner BSCU 20 and the outer BSCU 30 are configured to receive signals from the brake pedal 65, process the signals, and control valves in the hydraulic system 40. Each of the inner BSCU 20 and the outer BSCU 30 may be identical and include the same Figure 4Each of the inboard BSCU 20 and the outboard BSCU 30 includes a processing circuit 21 having one or more general and / or special purpose processors (including but not limited to one or more microprocessors, microcontrollers, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other circuits configured with appropriate software and / or firmware) that controls the various components according to program instructions stored in a memory circuit 22. The memory circuit 22 stores processing logic, programming code, and operating information for use by the processing circuit 21. According to various embodiments, the memory circuit 22 may include volatile memory, non-volatile memory, or both.

[0040] Each BSCU 20, 30 includes a shared control channel with an independent activation circuit that provides power to a hydraulic activation solenoid to control a shutoff valve 47 within the hydraulic brake system. The circuit may also control backup brake command drivers, which are isolation valve driver circuits that select the smaller of the two normal system brake commands.

[0041] The input interface 23 is configured to receive pilot input via a wired connection, such as a serial port, USB, micro USB, FIREWIRE, Lightning, and / or Thunderbolt connection. The input interface 23 may also be configured to receive pilot input via radio signals, electrical signals, and / or optical signals. The input interface 23 may also receive signals from one or more other sources, such as a flight controller that monitors the operation of the aircraft. Each BSCU 20, 30 may include a digital-to-analog converter 24 to convert a digital enable signal.

[0042] like Figure 4 As shown, each of the outboard BSCU 20 and the inboard BSCU 30 initially receives input signals from certain of the brake pedals 65. An analog signal based on the received digital signal is sent to the opposing BSCU 20, 30, indicating that the brake pedal 65 is activated. A digital position signal is also received, which indicates the position of the brake pedal 65 and the degree to which the pilot is applying the brakes. Figure 4 As shown, each BSCU 20, 30 shares with the other BSCU (20, 30) an analog enable signal indicating brake pedal activation and a digital position signal indicating the degree to which the pilot has activated the pedal. Thus, each BSCU 20, 30 is able to analyze each brake signal.

[0043] Each BSCU 20, 30 analyzes the inputs and selects the larger of the two pilot pedal inputs. The larger of the two pilot brake commands is selected to be applied to the brake 50 using the first brake module 41 of the hydraulic system 40. The smaller of the two front or rear brake commands is used for backup braking using the backup brake module 42.

[0044] like Figure 3 As shown, each BSCU 20, 30 includes two independent control channels to control the servo valve 46 in the first brake module 41. The outboard BSCU 20 includes: a first control channel 91 that pairs the brakes 50 of a pair of front outboard wheels 69a, 69b; and a second control channel 92 that pairs the brakes 50 of the rear outboard wheels 69c, 69d. Similarly, a first control channel 93 from the inboard BSCU 30 pairs the brakes 50 of the front inboard wheels 69e, 69f, and a second control channel 94 pairs the brakes 50 of the rear inboard wheels 69g, 69h.

[0045] Each BSCU 20 , 30 also includes a shared controlled channel to control backup braking. The BSCU 20 includes a shared control channel 95 leading to the backup brake module 42 , and likewise, the BSCU 30 includes a shared control channel 96 leading to the backup brake module 42 .

[0046] Figure 5 The brake command processing of each BSCU 20, 30 is illustrated. The brake pedal command is received by the BSCU 20, 30, which determines the larger of the two pilot brake signals (box 180). In the case of less than the slip pressure, the brake pressure is determined based on the angle of pedal deployment (box 182). The brake pressure can be determined via a lookup table. The determined brake pressure is then compared to the automatic brake pressure command (box 190), and the larger of the two is used to control the first brake module 41 (box 184).

[0047] In the event that the brake pressure is higher than the slip pressure, a brake command is generated via the normal anti-skid function. The anti-skid command (block 192 ) causes the brake pressure to be released (block 186 ) to prevent slipping in the event of a brake command being issued, thereby controlling the first brake module 41 .

[0048] For backup braking, the smaller of the front brake command and the rear brake command is sent to the shared channel. The shared channel also receives the smaller of the front brake command and the rear brake command from another BSCU 20, 30 (block 194). These signals are sent through the backup control channel to control the backup brake module 42.

[0049] The outboard BSCU 20 includes a control passage 95 to the backup brake module 42, which controls the servo valve 46 that controls the brakes 50 of the outboard wheels (69a, 69c) of the first wheelset 60 and the servo valve 46 that controls the brakes 50 of the outboard wheels (69b, 69d) of the second wheelset 60. The inboard BSCU 30 includes a control passage 96 for the servo valve 46 that controls the brakes 50 of the inboard wheels (69e, 69g) of the first wheelset 60 and the brakes 50 of the inboard wheels (69f, 69h) of the second wheelset 60.

[0050] like Figure 3 As shown, each wheelset 60 of the undercarriage shares a first brake module 41. The single first brake module 41 comprises a servo valve 46 which controls the braking on each wheel of the wheelset 60.

[0051] like Figure 3 and Figure 6 The hydraulic system 40 shown includes a first brake module 41 and a backup brake module 42. The first brake module 41 is supplied with hydraulic fluid via one or more first lines 43. The backup brake module 42 is supplied with hydraulic fluid via one or more second lines 70. These lines (43, 70) may include separate hydraulic fluid supplies to provide a redundant system in the event of a failure of one part of the hydraulic system 40. The brake 50 may be supplied with hydraulic fluid via a fail-safe supply to ensure braking of the wheel 69.

[0052] Line 43 provides hydraulic fluid to the first brake module 41, and line 70 provides hydraulic fluid to the backup brake module 42. Feed line 49 extends from the first brake module 41 to the shuttle valve module. Feed line 75 extends from the backup brake module 42 to the shuttle valve module 80. Feed line 82 extends from the shuttle valve module 80 to the brakes 50 of each wheel 69.

[0053] The first brake modules 41 each include an outer portion 44 and an inner portion 45. The outer portion 44 includes a servo valve 46 associated with the brake 50 of each outer wheel 69 of the wheel set 60. The inner portion 45 includes a servo valve 46 associated with the brake 50 of each inner wheel 69 of the wheel set 60. The servo valve 46 of the outer portion 44 is controlled by the outer BSCU 20, and the servo valve 46 of the inner portion 45 is controlled by the inner BSCU 30. A fuse 48 is positioned along the pipeline 49 to prevent the hydraulic system from being exhausted and causing downstream leakage. Each of the outer portion 44 and the inner portion 45 includes a shutoff valve 47 to reduce leakage of hydraulic fluid. The shutoff valve 47 can also prevent a single solenoid failure from inadvertently braking the wheel 69.

[0054] The backup brake module 42 includes a pair of servo valves 46. The first servo valve 46 is associated with a first line 75 through which hydraulic fluid is supplied to a pair of outboard brakes 50, and the second servo valve 46 is associated with a second line 75 that supplies hydraulic fluid to the inboard brake 50. Unlike the first brake module 41, which includes a servo valve dedicated to each brake 50, the backup brake module 42 includes a single servo valve 46 for both brakes 50. For each backup brake module 42, the servo valve 46 associated with the outboard brake 50 is controlled by the outboard BSCU 20, and the servo valve 46 associated with the inboard brake 50 is controlled by the inboard BSCU 30. A fuse 48 is positioned along each line 75 to prevent exhaustion of the hydraulic system and cause downstream leakage. The backup brake module 42 may include a shutoff valve 47 to prevent the flow of hydraulic fluid, such as Figure 3 shown.

[0055] The shuttle valve module 80 includes a shuttle valve 81 associated with each brake 50. Each shuttle valve 81 connects the hydraulic line 49 from the first brake module 41 with the line 75 from the backup brake module 42. Each shuttle valve 81 allows hydraulic fluid to flow from one of the lines (49, 75) through the shuttle valve and into the line 82 to control the associated brake 50. Hydraulic sensors 89 that detect fluid pressure can be positioned at various locations along the hydraulic system 40. This can include pressure sensors 89 positioned along each line 82, such as Figure 5 shown.

[0056] The hydraulic system 40 includes a plurality of supply lines, each supplying hydraulic fluid to control the braking of one of the wheels 69. Each supply line includes lines 49, 75, 82 and one or more of valves 46, 47, 81. Each supply line also includes a brake 50 to apply a braking force to one of the wheels 69.

[0057] In response to the pilot input, the outboard BSCU 20 generates brake control signals to control two sets of lines including valves 46, 47, 81 of a first wheelset having only the front outboard wheel 69 and two sets of lines including valves 46, 47, 81 of a second wheelset having only the rear outboard wheel 69. The inboard BSCU 30 generates brake control signals in response to the pilot input to control two sets of lines including valves 46, 47, 81 of a third wheelset having only the front inboard wheel 69 and two sets of lines including valves 46, 47, 81 of a fourth wheelset having only the rear inboard wheel 69.

[0058] Braking system 10 is configured to receive braking input from a pilot and apply a corresponding braking force. Figure 7A method of braking an aircraft is illustrated. Initially, a braking input is received from a brake pedal 65 (block 200). The braking input may include inputs from two or more pilots. Furthermore, the braking input may include one or more inputs from each pilot. Figure 3 In an embodiment, the braking input comprises a pair of inputs from each of the two pilots.

[0059] Braking inputs are received from the pilots at the BSCU 20, 30. The BSCU 20, 30 calculates which pilot input is greater (block 202). This calculation may include each BSCU 20, 30 calculating the magnitude of each pilot input based on the different pedal inputs. Figure 3 In the embodiment of the present invention, the calculation includes the outer BSCU 20 determining the extent of the input based on a first set of pedal inputs from each pilot, and the outer BSCU 30 determining the extent of the input based on a second set of pilot inputs. The BSCUs 20, 30 may share their calculations and both determine the maximum input. The determination of the extent of pilot input may also be calculated in other ways.

[0060] Once the greater input is determined, the BSCU 20, 30 uses the greater pilot input to control the first brake module 41 to control braking (block 204). For example, if the captain input is greater than the first officer input, the pilot input is used to control braking using the first brake module 41. This step includes the outboard BSCU 20 sending a braking command to the servo valve 46 of the first brake module 41 associated with the outboard wheel 69. This step also includes the inboard BSCU 30 sending a braking command to the servo valve 46 of the first brake module 41 associated with the inboard wheel 69. These commands are used to brake the aircraft.

[0061] The smaller of the braking commands between the front wheel pair and the rear wheel pair is used for backup braking (block 206). This step includes sending a braking command from the BSCU 20 to the servo valve 46 of the backup brake module 42 associated with the outer wheel 69, and sending a braking command from the BSCU 30 to the servo valve 46 associated with the inner wheel 69.

[0062] The above described braking system also provides braking of the aircraft in the event of a failure of one of the BSCUs 20, 30. In this case, the operational BSCU 20, 30 is able to control the braking to stop the aircraft.

[0063] The braking system 10 can be used in a variety of different aircraft. One aircraft includes a commercial aircraft that includes multiple rows of seats, each seat being configured to accommodate a passenger. Other aircraft include, but are not limited to, manned aircraft, unmanned aircraft, manned spacecraft, unmanned spacecraft, manned rotorcraft, unmanned rotorcraft, satellites, rockets, missiles, manned ground vehicles, unmanned ground vehicles, and combinations thereof.

[0064] The present disclosure may be implemented in other ways than those specifically set forth herein without departing from the essential features of the present disclosure. The present aspects are to be considered illustrative rather than restrictive, and all changes falling within the meaning and equivalent range of the appended claims are encompassed herein.

[0065] Furthermore, the present disclosure includes implementations according to the following clauses:

[0066] Clause 1. A braking system (10) for a dual-landing gear aircraft, the dual-landing gear aircraft comprising a left landing gear and a right landing gear, the left landing gear and the right landing gear each having a front inner wheel and a rear inner wheel and a front outer wheel and a rear outer wheel, the braking system comprising:

[0067] an outboard brake system control unit (20) comprising at least a first processing circuit (21) that generates brake control signals in response to pilot input to symmetrically control braking of a first wheel pair including only the front outboard wheel (69) and a second wheel pair including only the rear outboard wheel (69);

[0068] an inboard brake system control unit (30), the inboard brake system control unit comprising at least a second processing circuit (21), the second processing circuit generating a brake control signal in response to the pilot input to symmetrically control braking of a third wheel pair including only the front inboard wheel (69) and a fourth wheel pair including only the rear inboard wheel (69), the inboard brake system control unit (30) being independent of the outboard brake system control unit (20); and

[0069] A hydraulic system (40) applies a braking force to the wheel (69) in response to the brake control signal.

[0070] Clause 2. A braking system according to Clause 1, wherein: the outer braking system control unit (20) sends the braking control signal along a first control channel (91) to brake only the front outer wheels (69) of both the left landing gear and the right landing gear, and sends the braking control signal along a second control channel (92) to brake only the rear outer wheels (69) of both the left landing gear and the right landing gear, and the first control channel (91) is independent of the second control channel (92).

[0071] Clause 3. A braking system according to Clause 2, wherein: the inner braking system control unit (30) sends the braking control signal along a third control channel (93) to brake only the front inner wheels (69) of both the left landing gear and the right landing gear, and sends the braking control signal along a fourth control channel (94) to brake only the rear inner wheels (69) of both the left landing gear and the right landing gear, and the third control channel (93) is independent of the fourth control channel (94).

[0072] Clause 4. A braking system according to clause 1, wherein: the inner brake system control unit (20) and the outer brake system control unit (30) further include an input interface (23) for receiving the pilot input, the pilot input including a separate first input and a second input.

[0073] Clause 5. The braking system according to clause 1, wherein: the hydraulic system (40) comprises:

[0074] a first hydraulic line (49) and a backup line (75) supplying hydraulic fluid to a brake (50) at the wheel (69);

[0075] a servo valve (46) positioned along the first hydraulic line (49) and the backup line (75), the servo valve regulating the pressure of hydraulic fluid supplied to the brake (50) in response to the brake control signals received from the inboard brake system control unit (20) and the outboard brake system control unit (30);

[0076] A shuttle valve (81) operatively connects the first hydraulic line (49) and the backup line (75), the shuttle valve (81) supplying hydraulic fluid from one of the first hydraulic line (49) and the backup line (75).

[0077] Clause 6. A braking system according to Clause 5, wherein: each servo valve (46) positioned along the first hydraulic line (49) regulates the pressure for one of the brakes (50), and the servo valve (46) positioned along the backup supply line (75) regulates a pair of brakes (50) on one of the left landing gear and the right landing gear.

[0078] Clause 7. A braking system according to Clause 5, wherein the braking system further comprises: a first module (41), the first module accommodating each servo valve (46) for regulating the pressure of the hydraulic fluid along the first hydraulic line (49) to the brake (50) of one of the left landing gear and the right landing gear; and a second module (42), the second module accommodating each servo valve (46) for regulating the pressure of the hydraulic fluid along the second hydraulic line (75) to the brake (50) of the other of the left landing gear and the right landing gear.

[0079] Clause 8. The brake system according to clause 7, wherein each of the first module (41) and the second module (42) comprises a shut-off valve (47) for reducing leakage of the hydraulic fluid.

[0080] Clause 9. A braking system according to Clause 5, wherein: the outer brake system control unit (20) controls a servo valve (46) that supplies hydraulic fluid to each of the front outer wheel and the rear outer wheel (69), and the inner brake system control unit (30) controls a servo valve (46) that supplies hydraulic fluid to each of the front inner wheel and the rear inner wheel (69).

[0081] Clause 10. An aircraft having a braking system (10) according to clause 1.

[0082] Clause 11. A braking system (10) for a dual-landing gear aircraft, the dual-landing gear aircraft comprising a left landing gear and a right landing gear, the left landing gear and the right landing gear each having a front inner wheel and a rear inner wheel and a front outer wheel and a rear outer wheel, the braking system comprising:

[0083] A hydraulic system (40) comprising a plurality of supply lines (49, 75, 82), each of the plurality of supply lines supplying hydraulic fluid to control braking of one of the wheels (69), each of the plurality of supply lines (49, 75, 82) comprising:

[0084] a plurality of valves (46, 47, 81);

[0085] a brake (50) that applies a braking force to one of the wheels (69);

[0086] an outboard brake system control unit (20) comprising a first processing circuit (21) that generates brake control signals in response to pilot input to control valves (46, 47, 81) of a first wheelset including only the front outboard wheel (69) and valves (46, 47, 81) of a second wheelset including only the rear outboard wheel (69); and

[0087] an inner brake system control unit (30), the inner brake system control unit comprising a second processing circuit (21), the second processing circuit generating a brake control signal to control the valves (46, 47, 81) of a third wheel pair including only the front inner wheel (69) and the valves (46, 47, 81) of a fourth wheel pair including only the rear inner wheel (69);

[0088] The outboard brake system control unit (20) and the inboard brake system control unit (30) receive pilot input and control valves (46, 47, 81) of each of the wheelsets (69) to apply symmetrical braking forces to the wheels (69) of each of the wheelsets.

[0089] Clause 12. The braking system according to clause 11, further comprising:

[0090] a first control channel (91) extending between the outer brake system control unit (20) and one of the valves (46) on one of the supply lines (49) of the front outer wheel (69);

[0091] a second control channel (92) extending between the outer brake system control unit (30) and one of the valves (46) on one of the supply lines (49) to the rear outer wheel (69);

[0092] a third control channel (93) extending between the inner brake system control unit (30) and one of the valves (46) on one of the supply lines (49) to the front inner wheel (69); and

[0093] a fourth control channel (94) extending between the inner brake system control unit (30) and one of the valves (46) on one of the supply lines (49) for the rear inner wheel (69);

[0094] Each of the first control channel (91), the second control channel (92), the third control channel (93) and the fourth control channel (94) is independent of each other.

[0095] Clause 13. A braking system according to clause 11, wherein: the hydraulic system (40) includes a first hydraulic supply line (43) and a backup hydraulic supply line (70), and each of the supply lines (43, 70) also includes a shuttle valve (81), which selectively delivers the hydraulic fluid from the first hydraulic supply line (43) and one of the backup hydraulic supply lines (70) to the brake (50) based on the pilot input.

[0096] Clause 14. The braking system of clause 11, wherein: each of the inboard brake system control unit (20) and the outboard brake system control unit (30) receives pilot input from both the first pilot and the second pilot.

[0097] Clause 15. A method of braking an aircraft, the method comprising the steps of:

[0098] receiving pilot input at both the outboard brake system control unit (20) and the inboard brake system control unit (30);

[0099] Based on the pilot input, a first braking signal is sent from the outboard brake system control unit (20), and a first pair of front outboard wheels (69) of the right and left landing gears and a second pair of rear outboard wheels (69) on the right and left landing gears are symmetrically braked; and

[0100] Based on the pilot input, a second braking signal is sent from the inner brake system control unit (30), and the third pair of front inner wheels (69) of the right landing gear and the left landing gear and the fourth pair of rear inner wheels (69) on the right landing gear and the left landing gear are symmetrically braked.

[0101] Clause 16. The method according to Clause 15 further comprises the following steps: sending the first braking signal from the outer brake system control unit (20) to the first pair of front outer wheels (69) via a first control channel (91), and sending the first braking signal from the outer brake system control unit (20) to the second pair of rear outer wheels (69) via an independent second control channel (92).

[0102] Clause 17. The method according to Clause 16 further comprises the following steps: sending the second braking signal from the inner brake system control unit (30) to the third pair of front inner wheels (69) via a third control channel (93), and sending the second braking signal from the inner brake system control unit (30) to the fourth pair of rear inner wheels via an independent fourth control channel (94).

[0103] Clause 18. The method according to Clause 15 further comprises the following steps: determining the larger input of the first input and the second input based on the pilot input, and based on the larger input of the first input and the second input, sending the first braking signal from the outer brake system control unit (20) to symmetrically brake the first pair of outer wheels and the second pair of outer wheels (69), and based on the larger input of the first input and the second input, sending the second braking signal from the inner brake system control unit (30) to symmetrically brake the third pair of inner wheels and the fourth pair of inner wheels (69).

[0104] Clause 19. The method according to Clause 18 further comprising the steps of determining a smaller braking command between the front wheel pair and the rear wheel pair based on pilot input, and controlling backup braking based on the smaller braking command between the front wheel pair and the rear wheel pair.

[0105] Clause 20. The method of clause 15, further comprising the step of sending the braking signal to a servo valve (46) and regulating the flow of hydraulic fluid to regulate braking of the plurality of pairs of brakes (50).

Claims

1. A braking system (10) for a dual-landing gear aircraft, the dual-landing gear aircraft comprising a left landing gear and a right landing gear, the left landing gear and the right landing gear each having a front inner wheel and a rear inner wheel and a front outer wheel and a rear outer wheel, the braking system comprising: an outboard brake system control unit (20) comprising at least a first processing circuit (21) that generates a brake control signal in response to a pilot input to symmetrically control braking of a first wheel pair including only the front outboard wheel and a second wheel pair including only the rear outboard wheel; an inner brake system control unit (30), the inner brake system control unit comprising at least a second processing circuit (21), the second processing circuit generating a brake control signal in response to the pilot input to symmetrically control braking of a third wheel pair including only the front inner wheel and a fourth wheel pair including only the rear inner wheel, the inner brake system control unit (30) being independent of the outer brake system control unit (20); and a hydraulic system (40) that applies braking force to the front inner wheel, the rear inner wheel, the front outer wheel, and the rear outer wheel in response to the brake control signal, The inner brake system control unit (30) and the outer brake system control unit (20) further include an input interface (23) for receiving the pilot input, wherein the pilot input includes a separate first input and a second input.

2. The braking system according to claim 1, wherein: The outboard brake system control unit (20) sends the brake control signal along a first control channel (91) to brake only the front outboard wheels of both the left landing gear and the right landing gear, and sends the brake control signal along a second control channel (92) to brake only the rear outboard wheels of both the left landing gear and the right landing gear, the first control channel (91) being independent of the second control channel (92).

3. The braking system according to claim 2, wherein: The inner brake system control unit (30) sends the brake control signal along the third control channel (93) to brake only the front inner wheels of both the left landing gear and the right landing gear, and sends the brake control signal along the fourth control channel (94) to brake only the rear inner wheels of both the left landing gear and the right landing gear, and the third control channel (93) is independent of the fourth control channel (94).

4. The braking system according to claim 1, wherein: The hydraulic system (40) comprises: a first hydraulic line (49) and a backup line (75) supplying hydraulic fluid to brakes (50) at the front inside wheel, the rear inside wheel, the front outside wheel, and the rear outside wheel; a servo valve (46) positioned along the first hydraulic line (49) and the backup line (75) to regulate the pressure of hydraulic fluid supplied to the brake (50) in response to the brake control signals received from the inboard brake system control unit (30) and the outboard brake system control unit (20); A shuttle valve (81) operatively connects the first hydraulic line (49) and the backup line (75), the shuttle valve (81) supplying hydraulic fluid from one of the first hydraulic line (49) and the backup line (75).

5. The braking system according to claim 4, wherein: Each servo valve (46) located along the first hydraulic line (49) regulates pressure for one of the brakes (50), and the servo valve (46) located along the backup line (75) regulates pressure for a pair of brakes (50) on one of the left and right landing gears.

6. The braking system according to claim 4, further comprising: A first module (41) accommodating each servo valve (46) regulating the pressure of hydraulic fluid along the first hydraulic line (49) to the brake (50) of one of the left and right landing gears; and a second module (42) accommodating each servo valve (46) regulating the pressure of hydraulic fluid along the backup line (75) to the brake (50) of the other of the left and right landing gears.

7. The braking system according to claim 6, wherein: Each of the first module (41) and the second module (42) includes a shutoff valve (47) for reducing leakage of hydraulic fluid.

8. The braking system according to claim 4, wherein: The outer brake system control unit (20) controls a servo valve (46) that supplies hydraulic fluid to each of the front outer wheel and the rear outer wheel, and the inner brake system control unit (30) controls a servo valve (46) that supplies hydraulic fluid to each of the front inner wheel and the rear inner wheel.

9. An aircraft having a braking system (10) according to any one of claims 1 to 8.

10. A braking system (10) for a dual-landing gear aircraft, the dual-landing gear aircraft comprising a left landing gear and a right landing gear, the left landing gear and the right landing gear each having a front inner wheel and a rear inner wheel and a front outer wheel and a rear outer wheel, the braking system comprising: A hydraulic system (40), the hydraulic system comprising a plurality of supply lines, each of the plurality of supply lines supplying hydraulic fluid to control braking of one of the front inner wheel, the rear inner wheel, the front outer wheel and the rear outer wheel, each of the plurality of supply lines comprising: a plurality of valves (46, 47, 81); a brake (50) that applies a braking force to one of the front inner wheel, the rear inner wheel, the front outer wheel, and the rear outer wheel; an outboard brake system control unit (20) comprising a first processing circuit (21) that generates brake control signals in response to pilot input to control valves (46, 47, 81) of a first wheelset including only the front outboard wheel and valves (46, 47, 81) of a second wheelset including only the rear outboard wheel; and an inner brake system control unit (30), the inner brake system control unit comprising a second processing circuit (21), the second processing circuit generating a brake control signal to control the valves (46, 47, 81) of a third wheel pair including only the front inner wheel and the valves (46, 47, 81) of a fourth wheel pair including only the rear inner wheel; The outboard brake system control unit (20) and the inboard brake system control unit (30) receive pilot input and control valves (46, 47, 81) of each wheelset to apply symmetrical braking forces to the front inboard wheel, the rear inboard wheel, the front outboard wheel and the rear outboard wheel of each wheelset, Wherein, each of the inboard brake system control unit (30) and the outboard brake system control unit (20) receives pilot input from both the first pilot and the second pilot.

11. The braking system according to claim 10, further comprising: a first control channel (91) extending between the outer brake system control unit (20) and one of the valves (46) on one of the supply lines to the front outer wheel; a second control channel (92) extending between the outer brake system control unit (20) and one of the valves (46) on one of the supply lines to the rear outer wheel; a third control channel (93) extending between the inner brake system control unit (30) and one of the valves (46) on one of the supply lines to the front inner wheel; as well as a fourth control channel (94) extending between the inner brake system control unit (30) and one of the valves (46) on one of the supply lines to the rear inner wheel; The first control channel (91), the second control channel (92), the third control channel (93) and the fourth control channel (94) are independent of each other.

12. The brake system according to claim 10, wherein: The hydraulic system (40) includes a first hydraulic supply line (43) and a backup hydraulic supply line (70), and each of the first hydraulic supply line (43) and the backup hydraulic supply line (70) further includes a shuttle valve (81) that selectively delivers the hydraulic fluid from one of the first hydraulic supply line (43) and the backup hydraulic supply line (70) to the brake (50) based on the pilot input.

13. A method for braking an aircraft, the method comprising the following steps: receiving pilot input at both the outboard brake system control unit (20) and the inboard brake system control unit (30); Based on the pilot input, a first braking signal is sent from the outboard brake system control unit (20), and a first pair of front outboard wheels on the right landing gear and the left landing gear and a second pair of rear outboard wheels on the right landing gear and the left landing gear are symmetrically braked; Based on the pilot input, a second braking signal is sent from the inner brake system control unit (30), and the third pair of front inner wheels of the right landing gear and the left landing gear and the fourth pair of rear inner wheels on the right landing gear and the left landing gear are symmetrically braked; as well as A larger input of a first input and a second input is determined according to the pilot input, and based on the larger input of the first input and the second input, the first braking signal is sent from the outer brake system control unit (20) to symmetrically brake the first pair of front outer wheels and the second pair of rear outer wheels, and based on the larger input of the first input and the second input, the second braking signal is sent from the inner brake system control unit (30) to symmetrically brake the third pair of front inner wheels and the fourth pair of rear inner wheels.

14. The method according to claim 13, further comprising the steps of: The first braking signal is sent from the outer brake system control unit (20) to the first pair of front outer wheels via a first control channel (91), and the first braking signal is sent from the outer brake system control unit (20) to the second pair of rear outer wheels via an independent second control channel (92).

15. The method according to claim 14, further comprising the steps of: The second braking signal is sent from the inner brake system control unit (30) to the third pair of front inner wheels via a third control channel (93), and the second braking signal is sent from the inner brake system control unit (30) to the fourth pair of rear inner wheels via an independent fourth control channel (94).

16. The method according to claim 13, further comprising the steps of: A lesser of braking commands between the front wheel pair and the rear wheel pair is determined based on the pilot input, and backup braking is controlled based on the lesser of the braking commands between the front wheel pair and the rear wheel pair.

17. The method according to claim 13, further comprising the steps of: The braking signal is sent to a servo valve (46) and the flow of hydraulic fluid is adjusted to adjust the braking of multiple pairs of brakes (50).

Images