Parking brake system, method for operating a parking brake system, and aircraft

Abstract

Disclosed are a parking brake system, a method for operating a parking brake system, and an aircraft. A parking brake system includes: one or more pressure transducers that monitor fluid pressure of the parking brake system; and a brake selection device configured to indicate whether the parking brake system is in an engaged state or a disengaged state. The parking brake system includes one or more processors and a memory coupled to the one or more processors. The memory stores data including a database and program code that, when executed by the one or more processors, causes the parking brake system to determine that the fluid pressure of the parking brake system is less than a threshold pressure. In response to determining that the fluid pressure of the parking brake system is less than the threshold pressure, the parking brake system commands the brake selection device to indicate that the parking brake system is in a disengaged state.

Description

Technical Field

[0001] The present disclosure relates to a parking brake system. More particularly, the present disclosure is directed to a brake selection device that indicates the actual position of a parking brake system. Background Art

[0002] Aircraft include a parking brake lever or other selector mechanism that the pilot uses to engage the parking brake. Specifically, in at least some systems, the pilot can depress the brake pedal and then activate the parking brake lever, which in turn closes the hydraulic parking brake valve. When the parking brake valve is closed, pressurized hydraulic fluid is trapped within the brake. In other words, there is no mechanical linkage that holds the aircraft's parking brake in place.

[0003] In operation, the parking brake lever is pulled upward by the pilot into the engaged position, trapping fluid within the brake. However, it should be understood that the parking brake lever only reflects the commanded position of the parking brake, not the actual state of the braking system. Therefore, in the event that the parking brake valve is unable to maintain sufficient pressure to keep the parking brake system engaged, the parking brake lever remains in the engaged position. Summary of the Invention

[0004] According to several aspects, a parking brake system is disclosed. The parking brake system includes: one or more pressure transducers that monitor the fluid pressure of the parking brake system; a brake selection device configured to indicate that the parking brake system is in an engaged state or a disengaged state; one or more processors in electronic communication with the brake selection device and the one or more pressure transducers; and a memory coupled to the one or more processors. The memory stores data including a database and program code that, when executed by the one or more processors, causes the parking brake system to receive multiple brake signals indicating that the parking brake system is in an engaged state. In response to receiving the multiple brake signals, the parking brake system monitors the one or more pressure transducers to determine the fluid pressure of the parking brake system. The parking brake system determines that the fluid pressure of the parking brake system is less than a threshold pressure. In response to determining that the fluid pressure of the parking brake system is less than the threshold pressure, the brake control system commands the brake selection device to indicate that the parking brake system is in a disengaged state.

[0005] In another aspect, a method for operating a parking brake system is disclosed, wherein the parking brake system includes a brake selector configured to indicate whether the parking brake system is in an engaged state or a disengaged state. The method includes receiving, via a computer, a plurality of brake signals indicating that the parking brake system is in an engaged state. In response to receiving the plurality of brake signals, the method includes monitoring one or more pressure transducers to determine a fluid pressure of the parking brake system. The method also includes determining that the fluid pressure at the parking brake system is less than a threshold pressure. In response to determining that the fluid pressure at the parking brake system is less than the threshold pressure, the method includes commanding the brake selector to indicate that the parking brake system is in a disengaged state.

[0006] In another aspect, an aircraft having a parking brake system is disclosed. The aircraft includes: a plurality of pedals configured to generate a brake signal, wherein the brake signal indicates that the plurality of pedals are depressed; a parking brake valve configured to regulate the hydraulic pressure supplied to the parking brake system; one or more pressure transducers that monitor the hydraulic pressure of the parking brake system; and a brake selector configured to generate a setting signal in response to being placed in an engaged state. The brake selector indicates whether the parking brake system is engaged or disengaged. The aircraft also includes: one or more processors in electronic communication with the brake selector, the parking brake valve, the plurality of pedals, and the one or more pressure transducers; and a memory coupled to the one or more processors. The memory stores data, including a database and program code, which, when executed by the one or more processors, causes the parking brake system to receive the setting signal from the brake selector and the brake signals from the plurality of pedals. In response to receiving the setting signal from the brake selector and the brake signals from the plurality of pedals, causes the parking brake system to monitor the one or more pressure transducers to determine the hydraulic pressure of the parking brake system. The parking brake system also causes the parking brake system to determine whether the hydraulic pressure of the parking brake system is less than a threshold pressure. In response to determining that the hydraulic pressure of the parking brake system is less than a threshold pressure, the parking brake system is caused to command a brake selector to indicate that the parking brake system is in a disengaged state.

[0007] The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments; further details of these features, functions, and advantages can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0009] Figure 1 is a schematic diagram of a parking brake system for a vehicle according to an exemplary embodiment;

[0010] Figure 2 yes Figure 1 A schematic diagram of a brake selection device according to an exemplary embodiment is shown;

[0011] Figure 3 It shows the operation Figure 1 A process flow chart of a method of a parking brake system according to an exemplary embodiment is shown;

[0012] Figure 4 yes Figure 1 An alternative embodiment of a parking brake system according to an exemplary embodiment is shown, the embodiment including a bistable control valve shown in a closed position;

[0013] Figure 5 A bistable control valve is shown in an open position according to an exemplary embodiment to maintain pressure within a parking brake system when the brake control valve is not operated;

[0014] Figure 6 It shows the operation Figures 4 and 5 A process flow chart of a method of a parking brake system according to an exemplary embodiment is shown.

[0015] Figure 7 is a computer control system for operating the disclosed parking brake system according to an exemplary embodiment. DETAILED DESCRIPTION

[0016] The present invention is directed to a fault-tolerant parking brake system for a vehicle. The parking brake system includes: a parking brake valve configured to maintain fluid pressure in the parking brake system; one or more pressure transducers that monitor the fluid pressure of the brake system; and a brake selection device. The brake selection device is configured to indicate whether the parking brake system is in an engaged state or a disengaged state. The parking brake system also includes one or more processors that monitor the pressure transducers. If the one or more processors determine that the fluid pressure of the brake system is less than a threshold pressure, the processor instructs the brake selection device to indicate that the parking brake system is in a disengaged state. Therefore, the disclosed brake selection device reflects the actual position of the parking brake, rather than the commanded position.

[0017] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0018] Now refer to Figure 1 , shows a schematic diagram of a parking brake system 12 for a vehicle 10. The parking brake system 12 includes a brake selection device 20, a plurality of brake pedals 22 (in Figure 1 Only one brake pedal 22 is visible), a control module 24, a plurality of wheels 26 (in Figure 12, a plurality of brake pedals 22, a brake control valve 28, and a parking brake valve 30. As described below, the brake selector device 20 indicates the actual state of the parking brake system 12, not the commanded state of the parking brake system 12.

[0019] The brake selection device 20 is configured to indicate whether the parking brake system 12 is in an engaged state or a disengaged state. Figure 1 In the non-limiting embodiment shown, the brake selection device 20 includes a lever 38 that indicates the state of the parking brake system 12. Specifically, when the lever 38 is in the position shown, Figure 1 In the lowered position shown, the parking brake system 12 is in the disengaged state. However, when the lever 38 is moved to the raised position (shown in phantom), the parking brake system 12 is in the engaged state. Figure 1 Rod 38 is shown, but it should be understood that Figure 1 This is merely exemplary in nature and the brake selection device 20 may be any other type of selection device. For example, in an alternative embodiment, the brake selection device 20 is a button. The brake selection device 20 is configured to generate a setting signal 36 in response to being placed in an engaged state, wherein the setting signal 36 is sent to the control module 24. The control module 24 also provides power to the solenoid valve 35 of the brake selection device 20 (see FIG. 1 ) via a power line 37. Figure 2 ).

[0020] In an embodiment, the vehicle 10 is an aircraft. However, it should be understood that the disclosed parking brake system 12 can be used in any vehicle that utilizes a brake-by-wire system. In one non-limiting embodiment, the parking brake system 12 utilizes hydraulic brake fluid. However, the parking brake system 12 is not limited to a hydraulic system. For example, in another embodiment, the parking brake system 12 is a pneumatic system. It should also be understood that although Figure 1 Only a single parking brake system 12 is shown, but the aircraft may actually include multiple parking brake systems 12. For example, the aircraft may include separate brake systems corresponding to the left and right wheels of the aircraft.

[0021] Figure 2is an exemplary schematic diagram of the brake selection device 20. The brake selection device 20 includes a first switch SW1 and a solenoid valve 35 that are in electronic communication with the control module 24. In the embodiment shown in the figure, the first switch SW1 is a single-pole double-throw switch, however, it should be understood that other types of switches can also be used. The first switch SW1 includes two positions, "set" and "unset". The rod 38 is operably connected to both the first switch SW1 and the solenoid valve 35. Therefore, raising the rod 38 to the engaged state causes the first switch SW1 to be actuated to the "set" position, and the set signal 36 is sent to the control module 24. Similarly, lowering the rod 38 causes the first switch SW1 to be actuated to the "unset" position. The control module 24 provides power to the solenoid valve 35 via the power line 37, wherein the solenoid valve 35 is energized by the power provided by the power line 37 to lock the rod 38 in the raised position ( Figure 1 shown).

[0022] Reference Figure 1 , parking brake system 12 also includes a supply pressure conduit 40, a return pressure conduit 42, and a brake line conduit 44. Supply pressure conduit 40 is fluidly connected to brake control valve 28, return pressure conduit 42 is fluidly connected to parking brake valve 30, and brake line conduit 44 is fluidly connected to piston-cylinder assembly 32. Brake control valve 28 is configured to actuate between a closed position and an open position. When brake control valve 28 is in the closed position, brake control valve 28 fluidly connects brake line conduit 44 with return pressure conduit 42. When brake control valve 28 is in the open position, brake control valve 28 fluidly connects brake line conduit 44 with supply pressure conduit 40, and pressurized brake fluid is supplied to piston-cylinder assembly 32.

[0023] The parking brake valve 30 is configured to maintain fluid pressure within the parking brake system 12. Specifically, the parking brake valve 30 is configured to maintain fluid pressure at the piston-cylinder assembly 32 of the parking brake system 12. In an embodiment, if the parking brake system 12 is a hydraulic brake system, the parking brake valve 30 is configured to maintain hydraulic pressure within the parking brake system 12. The parking brake system 12 also includes a check valve 48 disposed in a conduit 46 connecting the brake control valve 28 and the parking brake valve 30. The check valve 48 prevents brake fluid from flowing out of the return pressure conduit 42 and into the brake control valve 28. When the parking brake valve 30 moves from the open position to the closed position, pressurized brake fluid remains in the brake line conduit 44. In other words, when the parking brake valve 30 is in the closed position, pressurized brake fluid remains in the brake line conduit 44 at a threshold pressure for a limited amount of time, and the parking brake system 12 is engaged, as discussed in more detail below.

[0024] The brake pack 34 includes one or more rotors 50 and one or more stators 52, wherein the rotors 50 rotate in conjunction with the wheels 26. The piston-cylinder assembly 32 includes a piston or force member 54, a cylinder 56, and a biasing element 66, wherein the force member 54 is configured to translate back and forth in a linear motion within the cylinder 56. In the illustrated embodiment, the biasing element 66 is a coil spring. When the brake control valve 28 is opened to fluidly connect the supply pressure conduit 40 with the brake line conduit 44, pressurized brake fluid is supplied to the piston-cylinder assembly 32, causing the force member 54 to overcome the biasing force applied by the biasing element 66. Once the force member 54 overcomes the biasing force, it translates within the cylinder 56 toward the brake pack 34. The force member 54 continues to travel toward the brake pack 34 until the end 60 of the force member 54 abuts the brake pack 34 and applies a compressive force on the brake pack 34. When the brake pack 34 is compressed, friction is generated between the rotor 50 and the stator 52 that resists rotation of the wheel 26 .

[0025] Continue to refer Figure 1 , the plurality of brake pedals 22 are operably coupled to a force member 54 located within a cylinder 56. Thus, when an operator depresses the plurality of brake pedals 22, this causes the force member 54 to translate within the cylinder 56 in a direction toward the brake group 34 to apply a compressive force on the brake group 34. Figure 1 As shown, the plurality of brake pedals 22 are in communication with the control module 24. The plurality of brake pedals 22 are configured to generate a depression signal 68 in response to being depressed. Specifically, the plurality of brake pedals 22 generate a depression signal 68 that is sent to the control module 24 in response to being depressed by an operator.

[0026] The parking brake system 12 also includes one or more pressure transducers 62 in electronic communication with the control module 24. The pressure transducers 62 monitor the fluid pressure of the parking brake system 12 and generate a proportional electrical signal referred to as a brake pressure signal 64. Specifically, the brake pressure signal 64 represents the fluid pressure at the piston-cylinder assembly 32 of the parking brake system 12.

[0027] The operator may attempt to place the parking brake system 12 in the engaged state. However, sometimes there is a fault in the parking brake system 12 that may prevent the parking brake system 12 from maintaining the engaged state because the parking brake system 12 cannot maintain sufficient pressure to maintain the engaged state. One example of a fault is when the parking brake valve 30 is not functioning and cannot remain in the closed position to maintain brake fluid pressure. Some other examples of faults that may prevent the parking brake system 12 from maintaining the engaged state include fluid escaping from the parking brake system 12 due to problems such as, for example, leaks in the pipes. Therefore, in the event that there is a fault in the parking brake system 12 that prevents the parking brake system 12 from maintaining the engaged state, the brake selector device 20 returns to the disengaged state. Therefore, the operator is informed of the actual state of the parking brake system 12, rather than the commanded state.

[0028] The operation of the parking brake system 12 will now be described. First, the control module 24 receives a plurality of brake signals indicating that the parking brake system 12 is being engaged. The parking brake signals indicate that an operator (such as a pilot) is attempting to engage the parking brake system 12. Specifically, in an embodiment, the plurality of brake signals include a set signal 36 generated by the brake selector 20 and a depressed signal 68 generated by the plurality of brake pedals 22.

[0029] In response to receiving the plurality of brake signals, the control module 24 instructs the parking brake valve 30 to move from an open position to a closed position. In other words, the control module 24 commands the parking brake valve 30 to close and block the return pressure conduit 42 of the parking brake system 12. As described above, when the parking brake valve 30 is in the closed position, pressurized brake fluid remains in the brake line conduit 44. In addition to closing the parking brake valve 30, in response to receiving the plurality of brake signals, the control module 24 monitors one or more pressure transducers 62 to determine the fluid pressure of the parking brake system 12. The control module 24 then compares the fluid pressure of the parking brake system 12 to a threshold pressure.

[0030] The threshold pressure represents the fluid pressure required to maintain the parking brake system 12 in the engaged state. Therefore, if the fluid pressure of the parking brake system 12 is less than the threshold pressure, this indicates that there is a fault in the parking brake system 12 that may prevent the parking brake system 12 from maintaining the engaged state. Specifically, if Figure 1 As shown, the parking brake valve 30 is fluidly connected to the cylinder 56. The threshold pressure indicates that the fluid pressure at the piston-cylinder assembly 32, as measured by the one or more pressure transducers 62, is sufficient to maintain the force member 54 in position within the cylinder 56 for a predetermined amount of time.

[0031] The predetermined amount of time varies between different types of parking brake systems. However, it should be understood that it is not expected that the parking brake system 12 maintain the threshold pressure for an infinite amount of time. In other words, because the parking brake valve 30 cannot maintain fluid pressure in the parking brake system for an infinite amount of time, the parking brake system 12 generally loses pressure over time. The predetermined amount of time is based on the parking brake valve 30. In one non-limiting embodiment, if the vehicle 10 is an aircraft, the predetermined amount of time ranges from approximately 12 hours to approximately 24 hours.

[0032] In one embodiment, the control module 24 determines that the fluid pressure of the parking brake system 12 is less than a threshold pressure. In response to determining that the fluid pressure of the parking brake system 12 (i.e., at the piston-cylinder assembly 32) is less than the threshold pressure, the control module 24 commands the brake selector 20 to indicate that the parking brake system 12 is in the disengaged state. For example, the control module 24 commands the brake selector 20 to move the lever 38 from the raised position (shown in dashed lines) to the lowered position. Furthermore, in response to determining that the fluid pressure of the parking brake system 12 is less than the threshold pressure, the control module 24 also commands the parking brake valve 30 to move back to the open position. Opening the parking brake valve 30 resets the parking brake system 12.

[0033] Alternatively, in another embodiment, the control module 24 determines that the fluid pressure of the parking brake system 12 is equal to or greater than a threshold pressure. In other words, the parking brake system 12 is capable of maintaining an engaged state. In response to determining that the fluid pressure of the parking brake system 12 is equal to or greater than the threshold pressure, the control module 24 continues to command the brake selector 20 to indicate that the parking brake system 12 is in the engaged state. For example, the control module 24 commands the brake selector 20 to maintain the lever 38 in the raised position (shown in dashed lines).

[0034] Figure 3 It shows the operation Figure 1 A process flow chart of an exemplary method 200 for the parking brake system 12 is shown. Figure 1 and Figure 3 In both embodiments, the method 200 begins at block 202. In block 202, the control module 24 receives a plurality of brake signals indicating that the parking brake system 12 is being engaged. For example, as shown in block 202A, in one embodiment, the plurality of brake signals include a set signal 36 generated by the brake selector 20 and a depressed signal 68 generated by the plurality of brake pedals 22. The method 200 may then proceed to blocks 204A and 204B.

[0035] In response to receiving the plurality of brake signals, the control module 24 monitors the one or more pressure transducers 62 to determine the fluid pressure of the parking brake system 12 in block 204A. In response to receiving the parking brake signals, the control module 24 commands the parking brake valve 30 to move from an open position to a closed position in block 202B. It should be understood that blocks 204A and 204B may be executed approximately simultaneously. The method 200 may then proceed to decision block 206.

[0036] In decision block 206 , the control module 24 compares the fluid pressure of the parking brake system 12 to a threshold pressure. In response to the control module 24 determining that the fluid pressure of the parking brake system 12 is less than the threshold pressure, the method 200 proceeds to block 208 .

[0037] In response to determining that the fluid pressure of the parking brake system 12 is less than the threshold pressure, the control module 24 commands the brake selector 20 to indicate that the parking brake system 12 is in the disengaged state in block 208. The method 200 may then terminate.

[0038] Referring back to decision block 206 , in response to the control module 24 determining that the fluid pressure of the parking brake system 12 is equal to or greater than the threshold pressure, the method 200 may proceed to block 210 .

[0039] In response to determining that the fluid pressure of the parking brake system 12 is equal to or greater than the threshold pressure, the control module 24 continues to command the brake selector 20 to indicate that the parking brake system 12 is in the engaged state in block 210. The method 200 may then terminate.

[0040] Figure 4 yes Figure 1 An alternative embodiment of the parking brake system 12 is shown in which the brake control valve 28 is a bistable control valve 128. The bistable control valve 128 is any type of control valve that is configured to maintain its last switched state even after the input signal is no longer available. In other words, if the control module 24 were to lose power, the bistable control valve 128 would still maintain its last switched state.

[0041] The bistable control valve 128 includes two switching states, namely a closed position and an open position. Figure 4 In the closed position shown, the fluid is connected to the return pressure conduit 42 of the parking brake system 12. The bistable control valve 128 is placed in the closed position as shown. Figure 5In the open position shown, the fluid is connected to the supply pressure conduit 40. Thus, when the bistable control valve 128 is in the open position, pressurized brake fluid from a supply source (not shown) is provided to the piston-cylinder assembly 32. In the embodiment, the bistable control valve 128 is a mechanically operated hydraulic control valve, however, it should be understood that other types of bistable control valves may be used instead.

[0042] In such Figure 4 In the embodiment shown, the parking brake valve 30 is not operated and the bistable control valve 128 is in the closed position. In other words, the parking brake valve 30 cannot be moved to the open position to block the supply of brake fluid to the return pressure conduit 42. Figure 4 As shown, unpressurized brake fluid is present in return pressure conduit 42, brake line conduit 44, and conduit 46 connecting bistable control valve 128 to parking brake valve 30. As a result, unpressurized brake fluid flows to return pressure conduit 42 of parking brake system 12.

[0043] When the parking brake valve 30 is not operated, the one or more pressure transducers 62 indicate that the fluid pressure of the parking brake system 12 is less than the threshold pressure. The control module 24 receives the fluid pressure of the parking brake system 12 as an input. The control module 24 then compares the fluid pressure of the parking brake system 12 with the threshold pressure and determines that the fluid pressure of the parking brake system 12 is less than the threshold pressure. In response to determining that the fluid pressure of the parking brake system 12 is less than the threshold pressure, the control module 24 commands the bistable control valve 128 to be actuated to the threshold pressure. Figure 5 Shown in the open position.

[0044] Figure 5 yes Figure 4 FIGURE 1 is an illustration of the parking brake system 12 in which the bistable control valve 128 has been actuated from a closed position to an open position. Figure 5 As shown, the bistable control valve 128, when in the open position, fluidly connects the brake line conduit 44 with the supply pressure conduit 40. As a result, pressurized brake fluid is present in the brake line conduit 44, and the parking brake system 12 is in the engaged state. Thus, even if the parking brake valve 30 is inoperative, the parking brake system 12 can still be placed in the engaged state.

[0045] Figure 6 It shows the operation Figure 4 and Figure 5 A process flow chart of an exemplary method 300 for the parking brake system 12 is shown. Figure 4 、 Figure 5 and Figure 6The method 300 begins at block 302. In block 302, the control module 24 receives a plurality of brake signals indicating that the parking brake system 12 is being engaged. For example, in one embodiment, the plurality of brake signals includes a set signal 36 generated by the brake selector 20 and a depressed signal 68 generated by the plurality of brake pedals 22. The method 300 may then proceed to blocks 304A and 304B.

[0046] In block 304A, in response to receiving the plurality of brake signals, the control module 24 monitors the one or more pressure transducers 62 to determine the fluid pressure of the parking brake system 12. In block 302B, in response to receiving the parking brake signal, the control module 24 commands the parking brake valve 30 to close and block the return pressure conduit 42. It should be understood that blocks 304A and 304B may be performed approximately simultaneously. The method 300 may then proceed to decision block 306.

[0047] In decision block 306 , the control module 24 compares the fluid pressure of the parking brake system 12 to a threshold pressure. In response to the control module 24 determining that the fluid pressure of the parking brake system 12 is less than the threshold pressure, the method 300 proceeds to block 308 .

[0048] In response to determining that the fluid pressure of the parking brake system 12 is less than the threshold pressure, the control module 24 commands the bistable control valve 128 from the closed position ( Figure 4 shown) is actuated to the open position ( Figure 5 ). Method 300 may then terminate.

[0049] Referring back to decision block 306 , in response to the control module 24 determining that the fluid pressure of the parking brake system 12 is equal to or greater than the threshold pressure, the method 300 may proceed to block 310 .

[0050] In response to determining that the fluid pressure of the parking brake system 12 is equal to or greater than the threshold pressure, the control module 24 continues to command the bistable control valve 128 to remain in the closed position in block 310 . The method 300 may then terminate.

[0051] With reference generally to the accompanying drawings, the disclosed parking brake system includes various technical effects and benefits. Specifically, the disclosed system provides an indication to the operator regarding the actual state of the parking brake system, rather than a commanded state. Thus, if a fault exists in the parking brake system that would cause the system to disengage, the operator will be aware of that state. Furthermore, the disclosed parking brake system provides a method for maintaining a desired brake fluid pressure to keep the parking brake system engaged, even when the parking brake valve is inoperative. Finally, unlike some other methods for keeping a parking brake system engaged, the bistable control valve does not require a mechanical connection between the brake pedal and the brake system.

[0052] Now refer to Figure 7 , the control module 24 is implemented on one or more computer devices or systems, such as an exemplary computer system 1030. The computer system 1030 includes a processor 1032, a memory 1034, a mass storage memory device 1036, an input / output (I / O) interface 1038, and a human-machine interface (HMI) 1040. The computer system 1030 is operatively coupled to one or more external resources 1042 via the network 1026 or the I / O interface 1038. The external resources may include, but are not limited to, servers, databases, mass storage devices, peripheral devices, cloud-based network services, or any other suitable computer resources that can be used by the computer system 1030.

[0053] The processor 1032 includes one or more devices selected from a microprocessor, a microcontroller, a digital signal processor, a microcomputer, a central processing unit, a field programmable gate array, a programmable logic device, a state machine, a logic circuit, an analog circuit, a digital circuit, or any other device that manipulates signals (analog or digital) based on operating instructions stored in the memory 1034. The memory 1034 includes a single memory device or multiple memory devices, including but not limited to read-only memory (ROM), random access memory (RAM), volatile memory, non-volatile memory, static random access memory (SRAM), dynamic random access memory (DRAM), flash memory, cache memory, or any other device capable of storing information. The mass storage memory device 1036 includes a data storage device such as a hard drive, an optical drive, a tape drive, a volatile or non-volatile solid-state device, or any other device capable of storing information.

[0054] The processor 1032 operates under the control of an operating system 1046 residing in the memory 1034. The operating system 1046 manages computer resources so that computer program code, embodied as one or more computer software applications, such as the application 1048 residing in the memory 1034, may have instructions executed by the processor 1032. In an alternative example, the processor 1032 may directly execute the application 1048, in which case the operating system 1046 may be omitted. One or more data structures 1049 also reside in the memory 1034 and may be used by the processor 1032, the operating system 1046, or the application 1048 to store or manipulate data.

[0055] The I / O interface 1038 provides a machine interface that operatively couples the processor 1032 to other devices and systems, such as the network 1026 or external resources 1042. The applications 1048 thus work in conjunction with the network 1026 or external resources 1042 by communicating via the I / O interface 1038 to provide various features, functions, applications, processes, or modules that comprise examples of the present disclosure. The applications 1048 also include program code that is executed by one or more external resources 1042, or that relies on functions or signals provided by other systems or network components external to the computer system 1030. In fact, given the nearly endless number of possible hardware and software configurations, one of ordinary skill in the art will appreciate that examples of the present disclosure may include applications that are external to the computer system 1030, distributed among multiple computers or other external resources 1042, or provided by computing resources (hardware and software) provided as a service (e.g., cloud computing services) via the network 1026.

[0056] The HMI 1040 is operatively coupled to the processor 1032 of the computer system 1030 in a known manner to allow a user to interact directly with the computer system 1030. The HMI 1040 may include a video or alphanumeric display, a touch screen, speakers, and any other suitable audio and visual indicators capable of providing data to the user. The HMI 1040 also includes input devices and controls such as an alphanumeric keyboard, pointing device, keypad, buttons, control knobs, microphone, etc., capable of accepting commands or input from the user and transmitting the typed input to the processor 1032.

[0057] The database 1044 can reside on the mass storage memory device 1036 and can be used to collect and organize data used by the various systems and modules described herein. The database 1044 can include data and supporting data structures for storing and organizing the data. Specifically, the database 1044 can be arranged with any database organization or structure, including but not limited to a relational database, a hierarchical database, a network database, or a combination thereof. A database management system in the form of a computer software application executed as instructions on the processor 1032 can be used to access information or data stored in records of the database 1044 in response to queries, wherein the queries can be dynamically determined and executed by the operating system 1046, other applications 1048, or one or more modules.

[0058] Furthermore, the present disclosure includes embodiments according to the following items:

[0059] Item 1. A parking brake system comprising one or more pressure transducers configured to monitor fluid pressure of the parking brake system, the parking brake system comprising:

[0060] a brake selection device configured to indicate whether the parking brake system is in an engaged state or a disengaged state;

[0061] one or more processors in electronic communication with the brake selection device and the one or more pressure transducers; and

[0062] A memory, coupled to the one or more processors, storing data including a database and program code that, when executed by the one or more processors, causes the parking brake system to:

[0063] receiving a plurality of brake signals indicating that a parking brake system is being engaged;

[0064] monitoring one or more pressure transducers to determine a fluid pressure of a parking brake system in response to receiving the plurality of brake signals;

[0065] determining that a fluid pressure of the parking brake system is less than a threshold pressure; and

[0066] In response to determining that the fluid pressure of the parking brake system is less than a threshold pressure, a brake selector is commanded to indicate that the parking brake system is in a disengaged state.

[0067] Item 2. The parking brake system of Item 1, further comprising a parking brake valve configured to maintain fluid pressure in the parking brake system, wherein the one or more processors execute instructions to:

[0068] In response to receiving the plurality of brake signals, the parking brake valve is commanded to move from an open position to a closed position.

[0069] Item 3. The parking brake system of Item 2, wherein the one or more processors execute instructions to:

[0070] In response to determining that the fluid pressure of the parking brake system is less than a threshold pressure, the parking brake valve is instructed to move back to the open position.

[0071] Item 4. The parking brake system of Item 1, wherein the one or more processors execute instructions to:

[0072] determining that a fluid pressure of the parking brake system is equal to or greater than a threshold pressure; and

[0073] In response to determining that the fluid pressure of the parking brake system is equal to or greater than the threshold pressure, the brake selector device is continuously commanded to indicate that the parking brake system is in the engaged state.

[0074] Item 5. The parking brake system of Item 1, further comprising a force member positioned within the cylinder.

[0075] Item 6. The parking brake system of Item 5, wherein the threshold pressure indicates that the fluid pressure of the parking brake system is sufficient to maintain the force member in position within the cylinder for a predetermined amount of time.

[0076] Item 7. The parking brake system of Item 1 , further comprising a plurality of brake pedals in communication with the one or more processors, wherein the plurality of brake pedals are configured to generate a depression signal in response to being depressed.

[0077] Item 8. The parking brake system of Item 7, wherein the brake select device is configured to generate a setting signal in response to being placed in an engaged state.

[0078] Item 9. The parking brake system according to Item 8, wherein the plurality of brake signals include a set signal generated by a brake selection device and a depression signal generated by a plurality of brake pedals.

[0079] Item 10. A method of operating a parking brake system, wherein the parking brake system includes a brake selection device configured to indicate whether the parking brake system is in an engaged state or a disengaged state, the method comprising:

[0080] receiving, by the computer, a plurality of brake signals indicating that the parking brake system is being engaged;

[0081] monitoring one or more pressure transducers to determine a fluid pressure of a parking brake system in response to receiving the plurality of brake signals;

[0082] determining that a fluid pressure at the parking brake system is less than a threshold pressure; and

[0083] In response to determining that the fluid pressure of the parking brake system is less than a threshold pressure, a brake selector is commanded to indicate that the parking brake system is in a disengaged state.

[0084] Item 11. The method according to Item 10, further comprising:

[0085] In response to receiving the plurality of brake signals, a parking brake valve is commanded to move from an open position to a closed position, wherein the parking brake valve is configured to maintain fluid pressure of the parking brake system.

[0086] Item 12. The method according to Item 10, further comprising:

[0087] determining, by the computer, that a fluid pressure of the parking brake system is equal to or greater than a threshold pressure; and

[0088] In response to determining that the fluid pressure of the parking brake system is equal to or greater than the threshold pressure, the brake selector device is continuously commanded to indicate that the parking brake system is in the engaged state.

[0089] Item 13. The method of Item 10, wherein the plurality of brake signals include a set signal generated by a brake selection device and a depression signal generated by a plurality of brake pedals as part of a parking brake system.

[0090] Item 14. The method of Item 10, wherein the parking brake system further comprises a force member positioned within the cylinder, and wherein the threshold pressure indicates that the fluid pressure of the parking brake system is sufficient to maintain the force member in position within the cylinder for a predetermined amount of time.

[0091] Item 15. An aircraft having a parking brake system, wherein the aircraft comprises:

[0092] a plurality of pedals configured to generate a brake signal, wherein the brake signal indicates that the plurality of pedals are depressed;

[0093] a parking brake valve configured to regulate hydraulic pressure supplied to the parking brake system;

[0094] one or more pressure transducers to monitor the hydraulic pressure of the parking brake system;

[0095] a brake select device configured to generate a setting signal in response to being placed in an engaged state, wherein the brake select device indicates whether the parking brake system is in an engaged state or a disengaged state;

[0096] one or more processors in electronic communication with the brake selection device, the parking brake valve, the plurality of pedals, and the one or more pressure transducers; and

[0097] A memory, coupled to the one or more processors, storing data including a database and program code, the program code, when executed by the one or more processors, causing the parking brake system to:

[0098] receiving a setting signal from a brake selection device and a brake signal from a plurality of pedals;

[0099] monitoring one or more pressure transducers to determine a hydraulic pressure of a parking brake system in response to receiving a setting signal from a brake selector device and a brake signal from a plurality of pedals;

[0100] determining that the hydraulic pressure of the parking brake system is less than a threshold pressure; and

[0101] In response to determining that the hydraulic pressure of the parking brake system is less than a threshold pressure, a brake selection device is commanded to indicate that the parking brake system is in a disengaged state.

[0102] Clause 16. The aircraft of clause 15, wherein the one or more processors execute instructions to:

[0103] The parking brake valve is commanded to move from an open position to a closed position in response to receiving a set signal from a brake selector device and a brake signal from a plurality of pedals.

[0104] Clause 17. The aircraft of clause 16, wherein the one or more processors execute instructions to:

[0105] In response to determining that the hydraulic pressure of the parking brake system is less than a threshold pressure, the parking brake valve is commanded to move back to the open position.

[0106] Clause 18. The aircraft of clause 15, wherein the one or more processors execute instructions to:

[0107] determining that the hydraulic pressure of the parking brake system is equal to or greater than a threshold pressure; and

[0108] In response to determining that the hydraulic pressure of the parking brake system is equal to or greater than the threshold pressure, the brake selector device is continuously commanded to indicate that the parking brake system is in the engaged state.

[0109] Item 19. The aircraft of Item 15, further comprising a force member positioned within the cylinder, wherein the parking brake valve is fluidly connected to the cylinder.

[0110] Item 20. The aircraft of Item 19, wherein the threshold pressure indicates that the hydraulic pressure at the parking brake valve is sufficient to maintain the force member in position within the cylinder for a predetermined amount of time.

[0111] Item 21. A parking brake system comprising a parking brake valve configured to maintain fluid pressure of the parking brake system and one or more pressure transducers that monitor the fluid pressure of the parking brake system, the parking brake system comprising:

[0112] a bistable control valve fluidly connected to the parking brake valve, wherein the bistable control valve is configured to actuate between an open position and a closed position;

[0113] one or more processors in electronic communication with the bistable control valve, the parking brake valve, and the one or more pressure transducers; and

[0114] A memory, coupled to the one or more processors, storing data including a database and program code, the program code, when executed by the one or more processors, causing the parking brake system to:

[0115] receiving a plurality of brake signals indicating that a user is engaging a parking brake system;

[0116] monitoring one or more pressure transducers to determine a fluid pressure of a parking brake system in response to receiving the plurality of brake signals;

[0117] determining that a fluid pressure of the parking brake system is less than a threshold pressure; and

[0118] In response to determining that the fluid pressure of the parking brake system is less than a threshold pressure, the bistable control valve is commanded to actuate to an open position.

[0119] Item 22. The parking brake system of Item 21, further comprising a return pressure conduit fluidly connected to the parking brake valve.

[0120] Item 23. The parking brake system of Item 22, wherein the bistable control valve is fluidly connected to a return pressure conduit of the parking brake system when placed in the closed position.

[0121] Item 24. The parking brake system of Item 21, further comprising a supply pressure conduit fluidly connected to the bistable control valve.

[0122] Item 25. The parking brake system of Item 24, further comprising a brake line conduit, wherein the bistable control valve fluidly connects the brake line conduit to the supply pressure conduit when the bistable control valve is in the open position.

[0123] Item 26. The parking brake system of Item 21, wherein the one or more processors execute instructions to:

[0124] In response to receiving the plurality of brake signals, the parking brake valve is commanded to close and block a return pressure conduit of the parking brake system.

[0125] Item 27. The parking brake system of Item 21, wherein the bistable control valve is a mechanically operated hydraulic control valve.

[0126] Item 28. The parking brake system of Item 21, further comprising a force member positioned within the cylinder, wherein the parking brake valve is fluidly connected to the cylinder.

[0127] Item 29. The parking brake system of Item 28, wherein the threshold pressure indicates that the fluid pressure at the parking brake is sufficient to hold the force member in position for a predetermined amount of time.

[0128] Item 30. The parking brake system of Item 21, further comprising a plurality of brake pedals in communication with the one or more processors, wherein the plurality of brake pedals are configured to generate a depression signal in response to being depressed.

[0129] Item 31. The parking brake system of Item 30, further comprising a brake select device, wherein the brake select device is configured to generate a set signal in response to being placed in an engaged state.

[0130] Item 32. The parking brake system of Item 31, wherein the plurality of brake signals include a set signal generated by a brake selection device and a depression signal generated by a plurality of brake pedals.

[0131] Item 33. A method of operating a parking brake system, wherein the parking brake system includes a parking brake valve and a bistable control valve fluidly connected to the parking brake valve, wherein the method comprises:

[0132] receiving, by the computer, a plurality of brake signals indicating that the parking brake system is being engaged;

[0133] monitoring one or more pressure transducers to determine a fluid pressure of a parking brake system in response to receiving the plurality of brake signals, wherein the one or more pressure transducers monitor the fluid pressure of the parking brake system;

[0134] determining that a fluid pressure of the parking brake system is less than a threshold pressure; and

[0135] In response to determining that the fluid pressure of the parking brake system is less than a threshold pressure, the bistable control valve is commanded to actuate from a closed position to an open position.

[0136] Item 34. The method according to Item 33, further comprising:

[0137] In response to receiving the plurality of brake signals, the parking brake valve is commanded to close and block a return pressure conduit of the parking brake system.

[0138] Item 35. The method of Item 33, further comprising:

[0139] determining, by the computer, that a fluid pressure of the parking brake system is equal to or greater than a threshold pressure; and

[0140] In response to determining that the fluid pressure of the parking brake system is equal to or greater than the threshold pressure, the bistable control valve continues to be commanded to remain in the open position.

[0141] Clause 36. An aircraft having a parking brake system, wherein the aircraft comprises:

[0142] a parking brake valve configured to maintain hydraulic pressure in a parking brake system;

[0143] one or more pressure transducers to monitor the hydraulic pressure of the parking brake system;

[0144] a bistable control valve fluidly connected to the parking brake valve, wherein the bistable control valve is configured to actuate between an open position and a closed position;

[0145] one or more processors in electronic communication with the bistable control valve, the parking brake valve, and the one or more pressure transducers; and

[0146] A memory, coupled to the one or more processors, stores data including a database and program code, which, when executed by the one or more processors, causes the parking brake system to:

[0147] receiving a plurality of brake signals indicating that a user is engaging a parking brake system;

[0148] monitoring one or more pressure transducers to determine a hydraulic pressure of a parking brake system in response to receiving the plurality of brake signals;

[0149] determining that the hydraulic pressure of the parking brake system is less than a threshold pressure; and

[0150] In response to determining that the hydraulic pressure of the parking brake system is less than a threshold pressure, the bistable control valve is commanded to actuate to an open position.

[0151] Item 37. The aircraft of Item 36, further comprising a return pressure conduit fluidly connected to the parking brake valve, wherein the bistable control valve is fluidly connected to the return pressure conduit of the parking brake system when placed in the closed position.

[0152] Clause 38. The aircraft of clause 36, wherein the one or more processors execute instructions to:

[0153] In response to receiving the plurality of brake signals, the parking brake valve is commanded to close and block a return pressure conduit of the parking brake system.

[0154] Item 39. The aircraft of Item 36, wherein the bistable control valve is a mechanically operated hydraulic control valve.

[0155] Item 40. The aircraft of Item 36, further comprising a force member positioned within the cylinder, wherein the parking brake valve fluid is connected to the cylinder, and wherein the threshold pressure indicates that the hydraulic pressure of the parking brake system is sufficient to maintain the force member in the proper position within the cylinder for a predetermined amount of time.

[0156] The description of the present disclosure is merely exemplary in nature and variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.

Claims

1. A parking brake system (12), comprising: one or more pressure transducers (62) for monitoring fluid pressure in the parking brake system (12); a brake selection device (20) configured to provide a visual indication to an operator of the parking brake system (12) that the parking brake system (12) is in an engaged state or a disengaged state, wherein the brake selection device indicates an actual state of the parking brake system rather than a commanded state, and wherein the actual state of the parking brake system is determined based on a fluid pressure of the parking brake system monitored by the one or more pressure transducers; one or more processors (1032) in electronic communication with the brake selection device (20) and the one or more pressure transducers (62); and A memory (1034) is coupled to the one or more processors (1032), wherein the memory (1034) stores data including a database and program code, wherein the program code, when executed by the one or more processors (1032), causes the parking brake system (12) to perform the following: receiving one or more brake signals indicating that the parking brake system (12) is being placed in the engaged state, wherein the engaged state is the commanded state; In response to receiving the one or more brake signals, monitoring the one or more pressure transducers (62) to determine the fluid pressure of the parking brake system (12); determining that the fluid pressure of the parking brake system (12) is less than a threshold pressure; and In response to determining that the fluid pressure of the parking brake system (12) is less than the threshold pressure, the brake selection device (20) is commanded to indicate that the parking brake system (12) is in the disengaged state, wherein the disengaged state is the actual state.

2. The parking brake system (12) of claim 1, further comprising a parking brake valve (30), the parking brake valve (30) being configured to maintain the fluid pressure of the parking brake system (12), wherein The one or more processors (1032) execute instructions to: In response to receiving the one or more brake signals, commanding the parking brake valve (30) to move from an open position to a closed position, and In response to determining that the fluid pressure of the parking brake system (12) is less than the threshold pressure, the parking brake valve (30) is commanded to move back to the open position.

3. The parking brake system (12) according to claim 1, wherein: The one or more processors (1032) execute instructions to: determining that the fluid pressure of the parking brake system (12) is equal to or greater than the threshold pressure; and In response to determining that the fluid pressure of the parking brake system (12) is equal to or greater than the threshold pressure, the brake selection device (20) is continued to be commanded to indicate that the parking brake system (12) is in the engaged state.

4. The parking brake system (12) of claim 1, further comprising a force member (54) positioned within the cylinder (56), and wherein The threshold pressure indicates that the fluid pressure of the parking brake system (12) is sufficient to hold the force member (54) in place within the cylinder (56) for a predetermined amount of time.

5. The parking brake system (12) of claim 1, further comprising a plurality of brake pedals (22), the plurality of brake pedals (22) being in communication with the one or more processors (1032), wherein: The plurality of brake pedals (22) are configured to generate a depression signal (68) in response to being depressed.

6. The parking brake system (12) according to claim 1, wherein: The brake select device (20) is configured to generate a set signal (36) in response to being placed in the engaged state.

7. An aircraft (10) having a parking brake system (12) according to claim 1.

8. A method of operating a parking brake system (12), wherein: The parking brake system (12) includes a brake selection device (20) configured to indicate whether the parking brake system (12) is in an engaged state or a disengaged state, wherein the brake selection device provides a visual indication to an operator of the parking brake system that the parking brake system is in an engaged state or a disengaged state and indicates an actual state of the parking brake system rather than a commanded state, and wherein the actual state of the parking brake system is determined based on a fluid pressure of the parking brake system monitored by one or more pressure transducers, the method comprising: receiving, by a computer, one or more brake signals instructing the parking brake system (12) to be placed in the engaged state, wherein the engaged state is the commanded state; In response to receiving the one or more brake signals, monitoring one or more pressure transducers (62) to determine a fluid pressure of the parking brake system (12); determining that the fluid pressure at the parking brake system (12) is less than a threshold pressure; and In response to determining that the fluid pressure of the parking brake system (12) is less than the threshold pressure, the brake selection device (20) is commanded to indicate that the parking brake system (12) is in the disengaged state, wherein the disengaged state is the actual state.

9. The method according to claim 8, further comprising: In response to receiving the one or more brake signals, a parking brake valve (30) is commanded to move from an open position to a closed position, wherein the parking brake valve (30) is configured to maintain the fluid pressure of the parking brake system (12).

10. The method according to claim 8, further comprising: determining, by the computer, that the fluid pressure of the parking brake system (12) is equal to or greater than the threshold pressure; and In response to determining that the fluid pressure of the parking brake system (12) is equal to or greater than the threshold pressure, a brake selection device (20) is continued to be commanded to indicate that the parking brake system (12) is in the engaged state.

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