Abstract: A method for providing anti-skid braking control for a vehicle having a plurality of wheels, each wheel including a corresponding wheel speed sensor and brake, wherein when velocity data from at least one wheel speed sensor is lost, velocity data from a wheel speed sensor coupled to a different wheel is used as the wheel speed for the wheel with the non-operational sensor.

Abstract: A differential brake control system is provided for a vehicle having first and second wheels on respective sides of a vertical axis of the vehicle. The system includes processing logic for computing a wheel brake command based on an input brake command indicative of a desired amount of braking. In addition, the system includes differential logic for adjusting the wheel brake command by first and second amounts to produce first wheel and second wheel brake commands, respectively, the first amount being different from the second amount.

Abstract: The method for reducing aircraft carbon brake wear involves monitoring the commanded initiation of braking, and setting a residual brake clamping force to a predetermined minimum residual brake clamping force, which is maintained following the commanded initiation of braking to prevent release of braking during taxiing of the aircraft. The minimum residual brake clamping force is applied despite a commanded release of braking until at least one predetermined control logic condition occurs.

Abstract: Methods and systems are provided for improving brake performance, including extending the life of carbon brakes on aircraft. One embodiment of the method comprises measuring the speed of the aircraft and the intensity of braking and comparing these to predetermined maximum values for each. If the values are both lower than the maximum values, one or more of the brakes are selectively disabled.

Abstract: The method for reducing aircraft carbon brake wear involves monitoring the commanded initiation of braking, and setting a residual brake clamping force to a predetermined minimum residual brake clamping force, which is maintained following the commanded initiation of braking to prevent release of braking during taxiing of the aircraft. The minimum residual brake clamping force is applied despite a commanded release of braking until at least one predetermined control logic condition occurs.

Abstract: A brake controller function to optimally brake a wheel of a vehicle in motion, such as an aircraft. The brake pressure control self regulates by means of applying brake pressure in accordance with vehicle acceleration information and the change in acceleration over time in the horizontal plane. Vehicle acceleration and information about its change enable a brake pressure control function to determine the brake pressure associated with maximum obtainable retardation for a vehicle at that given point in time. By continuously monitoring acceleration change and detecting retardation pinnacles, the culmination and turning points of retardation, with their associated brake pressure, maximum braking ability is assured at any given time. By applying acceleration data in real time as a controls reference in a brake logic control function to increase or reduce brake pressure, such a brake control function will assure a brake pressure perfectly fit with net of all the forces that a vehicle is subjected to.

Abstract: Improved anti-lock brake systems (ABS) employed on aircraft and land vehicles and methods of operating same employing a sliding mode observer (SMO) incorporated into an ABS algorithm requiring only measurement of wheel speed to regulate the application of braking torque are disclosed. Braking is optimized simply by maintaining an SMO estimate of differential wheel torque (road/tire torque minus applied brake torque) derived from wheel speed at an extremum via applying or releasing the brakes as the extremum is passed through.

Abstract: A method of distribution braking between the brakes of an aircraft. The method includes a first step of estimating a braking force objective and a steering torque objective to be achieved by the brakes of the aircraft. It also includes the steps of defining at least two groups of brakes (12, 13) and determining, for each group, a braking level that is to be achieved by the group. The braking levels being calculated in such a manner that braking performed in application of the braking levels is, at least under normal operating conditions of the brakes, in compliance with a braking force objective and with a steering torque objective.

Abstract: An electric brake system for an aircraft as described herein electrically actuates brake mechanisms in a seamless manner when a power interrupt condition is experienced. While operating in an autobraking mode and in response to a power interrupt condition, the electric brake system preserves the last brake actuation command generated by the autobrake function. After normal operating power is reestablished, the last brake actuation command is retrieved and processed by the electric brake system. While operating in a pedal braking mode and in response to a power interrupt condition, the electric brake system discards the last brake actuation command generated from brake pedal interaction. After normal operating power is reestablished, the brake pedal data is refreshed to generate a new brake actuation command. These procedures reduce lurching and unexpected brake actuation levels following a power interrupt in the electric brake system.

Abstract: An anti-skid brake control system for a multi-wheeled vehicle includes both a paired function and an individual function. The paired function controls the wheels of the vehicle in unison. The individual function controls the wheels of the vehicle individually. A paired/individual logic circuit alternatively activates and deactivates the paired function and the individual function. A method for controlling the skid of a vehicle utilizing a paired function and a individual function is also provided.

Abstract: A system and methods for an electric autobrake function suitable for use with an aircraft is disclosed. The system includes a single master autobrake channel configured to generate a master autobrake command and a plurality of slave autobrake channels configured to receive the autobrake master command. The methods receive autobrake command actuation data, compute a common autobrake master command based upon the autobrake command actuation data, and synchronize brake application by utilizing the common autobrake master command to actuate all brake actuators.

Abstract: The method for reducing aircraft carbon brake wear involves monitoring the commanded initiation of braking, and setting a residual brake clamping force to a predetermined minimum residual brake clamping force, which is maintained following the commanded initiation of braking to prevent release of braking during taxiing of the aircraft. The minimum residual brake clamping force is applied despite a commanded release of braking until at least one predetermined control logic condition occurs.

Abstract: An electric brake system for an aircraft employs a brake control process to alleviate high dynamic structural loading of the aircraft landing gear caused by braking maneuvers. The system obtains and processes real-time data—which may include the current aircraft speed, the current brake pedal deflection position, and the current brake pedal deflection rate—to determine how best to control the onset of the brakes. The braking control scheme delays the onset of the desired braking condition to reduce high dynamic loading and lurching of the aircraft.

Abstract: A method for providing anti-skid braking control for a vehicle having a plurality of wheels, each wheel including a corresponding wheel speed sensor and brake, wherein when velocity data from at least one wheel speed sensor is lost, velocity data from a wheel speed sensor coupled to a different wheel is used as the wheel speed for the wheel with the non-operational sensor.

Abstract: An electric brake system for an aircraft employs a brake control process to alleviate high dynamic structural loading of the aircraft landing gear caused by braking maneuvers. The system obtains and processes real-time data—which may include the current aircraft speed, the current brake pedal deflection position, and the current brake pedal deflection rate—to determine how best to control the onset of the brakes. The braking control scheme delays the onset of the desired braking condition to reduce high dynamic loading and lurching of the aircraft.

Abstract: A braking system (1) for an aircraft which includes a by-pass control system (9) for activation when undemanded braking or loss of braking is detected.

Abstract: The method of maintaining optimal braking and skid protection for a two-wheeled vehicle wheel with a wheel speed sensor failure involves providing pulsed braking pressure to the affected wheel with the wheel speed sensor failure. If an incipient or initial skid on another wheel with a functioning wheel speed sensor has occurred, the pulsed braking pressure to the affected wheel is limited to the brake pressure command that caused the last incipient or initial skid on the other wheel, scaled by a factor for safety. Otherwise the pulsed braking pressure to the affected wheel is limited to be no greater than the greatest commanded brake pressure to the other wheel. The pulsed braking pressure is also limited to be less than the brake pressure commanded to the affected wheel.

Abstract: An electric brake system for an aircraft includes a power interlock mechanism that prevents inadvertent (uncommanded) application of brakes. The interlock removes operating power from the brake mechanisms whenever the brake system sensor data does not indicate a legitimate brake application condition. The interlock processing occurs in parallel with the brake command processing such that even if an inadvertent brake command is generated, the brake mechanisms will be unable to act upon the inadvertent brake command.

Abstract: The method for reducing aircraft carbon brake wear involves monitoring the commanded initiation of braking, and setting a residual brake clamping force to a predetermined minimum residual brake clamping force, which is maintained following the commanded initiation of braking to prevent release of braking during taxiing of the aircraft. The minimum residual brake clamping force is applied despite a commanded release of braking until at least one predetermined control logic condition occurs.

Abstract: A system and procedures for controlling a brake status indicator for an aircraft having an electric brake system are disclosed. Electric activation and deactivation of the brake status indicator mimics that of legacy hydraulic brake systems. The control methodology obtains brake force data that indicates actual clamping force of the electric brake actuators, parking brake lever status data that indicates whether the parking brake lever is raised or lowered, and parking brake activation data that indicates whether the parking brake mechanisms are active or inactive. The individual indicator elements of the brake status indicator are independently and concurrently controlled using multiple processing modules/channels of the electric brake system.

Abstract: The method and system for increasing accuracy of clamping force of electric aircraft carbon brakes, once braking has been commenced, provides a first pair of electric brake actuators with a range of low brake clamping force responsive to low brake clamping force commands, and a second pair of electric brake actuators with a range of high brake clamping force responsive to high brake clamping force commands. The first pair of electric brake actuators is actuated to apply a minimum residual braking force once wheel braking is commenced, and the second pair of electric brake actuators is actuated only when the commanded braking force is in the high range of brake clamping force.

Abstract: The method for reducing aircraft carbon brake wear involves monitoring the commanded initiation of braking, and setting a residual brake clamping force to a predetermined minimum residual brake clamping force, which is maintained following the commanded initiation of braking to prevent release of braking during taxiing of the aircraft. The minimum residual brake clamping force is applied despite a commanded release of braking until at least one predetermined control logic condition occurs.

Abstract: The method and system for increasing accuracy of clamping force of electric aircraft carbon brakes, once braking has been commenced, provides a first pair of electric brake actuators with a range of low brake clamping force responsive to low brake clamping force commands, and a second pair of electric brake actuators with a range of high brake clamping force responsive to high brake clamping force commands. The first pair of electric brake actuators is actuated to apply a minimum residual braking force once wheel braking is commenced, and the second pair of electric brake actuators is actuated only when the commanded braking force is in the high range of brake clamping force.

Abstract: The invention relates to an architecture for a braking system for an airplane fitted with a plurality of undercarriages each carrying a plurality of wheels, at least some of which are fitted with brakes, the architecture comprising at least two braking computers each having two modules such that in each computer, one of the modules controls a first fraction of the brakes and the other module controls a second fraction of the brakes complementary to the first. According to the invention, the architecture is configured to operate in any one of the following modes of operation: a first normal mode in which both modules of one of the braking computers are active for controlling all of the brakes; a second normal mode in which both modules of the other braking computer are active for controlling all of the brakes; and an alternative mode in which one module of one of the braking computers and one module of the other braking computer are active for controlling all of the brakes.

Abstract: An electric autobrake interlock system for an aircraft includes an autobrake power interlock mechanism that prevents inadvertent (uncommanded) application of brakes. The autobrake power interlock removes operating power from the brake actuators whenever the autobrake actuation data does not indicate a legitimate autobrake application condition. The interlock processing occurs in parallel with the autobrake command processing such that even if an inadvertent autobrake command is generated, the brake actuators will be unable to act upon the inadvertent autobrake command. In this regard, the brake actuators are unable to apply brakes automatically unless the following two actions happen concurrently: the operating power is provided to enable the electric brake actuators and autobrake actuation control is commanded in response to the legitimate autobrake application condition.

Abstract: An anti-skid brake control system for a multi-wheeled vehicle includes both a paired function and an individual function. The paired function controls the wheels of the vehicle in unison. The individual function controls the wheels of the vehicle individually. A paired/individual logic circuit alternatively activates and deactivates the paired function and the individual function. A method for controlling the skid of a vehicle utilizing a paired function and a individual function is also provided.

Abstract: The adaptive brake application and initial skid detection system allows rapid brake application and prevents deep initial skids. Brake pressure is compared with a predetermined threshold brake pressure. Wheel velocity error signals are also generated to mediated/indicate the difference between the wheel velocity and a reference velocity signal. A pressure bias modulator integrator responsive to brake pressure signals adjusts the wheel velocity error signals to provide an anti-skid control signal. The pressure bias modulator integrator can also be initialized to the value of the measured brake pressure when the wheel velocity error signals indicate the beginning of a skid. Brake pressure difference signals are generated to indicate the difference between brake pressure and a commanded brake pressure, and an adjusted brake pressure error signal is generated in response to the brake pressure difference signals.

Abstract: The invention relates to a system to control the deceleration of an aircraft during the taxiing phase on a landing strip, the system has a detector of the current position of the aircraft on the strip, and of the current speed of the aircraft on the strip, a calculator receiving position and speed values from the detector, to define, as a function of the desired final speed of the aircraft at the so-called final position on the strip, a deceleration set-point modification time, after the current time, and a new deceleration set-point to apply from the modification time, to reach the final position at the desired speed.

Abstract: A valve for controlling an emergency brake system on an aircraft. The valve has separate poppets for controlling the flow of fluid from a supply line to the brake cylinders and from the brake cylinders to a tank return line. The poppets act on each other. A dampening orifice restricts fluid flow around one of the poppets thereby limiting the rate at which that poppet opens and closes. An actuator applies an externally generated control force to the poppets to activate and de-active the emergency brake system.

Abstract: The adaptive brake application and initial skid detection system allows rapid brake application and prevents deep initial skids. Brake pressure is compared with a predetermined threshold brake pressure. Wheel velocity error signals are also generated to indicated the difference between the wheel velocity and a reference velocity signal. A pressure bias modulator integrator responsive to brake pressure signals adjusts the wheel velocity error signals to provide an anti-skid control signal. The pressure bias modulator integrator can also be initialized to the value of the measured brake pressure when the wheel velocity error signals indicate the beginning of a skid. Brake pressure difference signals are generated to indicate the difference between brake pressure and a commanded brake pressure, and an adjusted brake pressure error signal is generated in response to the brake pressure difference signals.

Abstract: Improved methods and systems for controlling hydraulically or electrically actuated anti-lock brake systems (ABS) on air and land vehicles requiring only measurement of wheel angular speed although brake torque measurements can also be employed if available. A sliding mode observer (SMO) based estimate of net or different wheel torque (road/tire torque minus applied brake torque) derived from the measured wheel speed is compared to a threshold differential wheel torque derived as a function of a “skid signal” also based on wheel speed only to generate a braking control signal. The braking control signal can be employed to rapidly and fully applying and releasing the brakes in a binary on-off manner and, as an additional option, possibly modulating the maximum available brake hydraulic pressure or electrical current when the brakes are in the “on” state in a continuous manner.

Abstract: Methods and systems for controlling wheel brakes on aircraft and other vehicles. In one embodiment, a method for slowing a vehicle on the ground can include applying a first brake to a first wheel and a second brake to a second wheel. The method can further include determining if a first speed sensor associated with the first wheel and a second speed sensor associated with the second wheel are operative. When the first and second speed sensors are operative, the first and second brakes can be controlled according to a first routine. Conversely, when at least one of the first and second speed sensors is inoperative, the first and second brakes can be controlled according to a second routine.

Abstract: The sliding, integral, and proportional controller for providing aircraft antiskid braking control includes a reference velocity subsystem, a velocity error ratio subsystem, and a main controller subsystem generating a control command output signal indicative of a command braking pressure. The main controller subsystem includes a one dimensional sliding mode controller subsystem to determine an estimated net wheel torque signal, an adaptive threshold subsystem for generating an adaptive threshold based upon the modified slip ratio signal and a clock signal, integral gain subsystems, a proportional controller subsystem, and a pressure limiter. A method for determining braking efficiency of an aircraft braking system independent of the specific conditions is also provided.

Abstract: The adaptive brake application and initial skid detection system allows rapid brake application and prevents deep initial skids. Brake torque is compared with a predetermined threshold brake torque. Wheel velocity error signals are also generated to indicated the difference between the wheel velocity and a reference velocity signal. A torque bias modulator integrator responsive to brake torque signals adjusts the wheel velocity error signals to provide an anti-skid control signal. The torque bias modulator integrator can also be initialized to the value of the measured brake torque when the wheel velocity error signals indicate the beginning of a skid. Brake torque difference signals are generated to indicate the difference between brake torque and a commanded brake torque, and an adjusted brake torque error signal is generated in response to the brake torque difference signals.

Abstract: The invention relates to a system to control the deceleration of an aircraft during the taxiing phase on a landing strip, the system comprising:

Abstract: A combination brake and anti-lock system for a wheeled vehicle such as an aircraft includes an operator controlled source of pressurized hydraulic fluid for selectively applying hydraulic pressure to a hydraulically actuated wheel rotation braking device which responds to the applied hydraulic pressure to apply a braking force to a wheel of the vehicle to thereby arresting wheel motion. There is a low pressure hydraulic fluid return with a normally open hold valve in circuit between the source and the braking device for selectively opening and closing a fluid flow path from the source to the braking device and a normally closed decay valve in circuit between the braking device and the return for selectively opening and closing a fluid flow path from the braking device to the return.

Abstract: An electrically actuated braking system (30) of the type having a plurality of brake actuators (35, 37, 39, 41, 43, 45, 47, 49) disposed on a carrier housing (13) to selectively apply a braking force to effect the restraint of wheel rotation has the particular actuators employed during a braking event determined, at least in part, by monitored wheel motion. The system (30) reduces brake energy consumption and heat generation during slow speed operations, reduces braking induced vibration, and compensates for individual actuator failure.

Abstract: An electrically actuated braking system (30) of the type having a plurality of brake actuators (35, 37, 39, 41, 43, 45, 47, 49) disposed on a carrier housing (13) to selectively apply a braking force to effect the restraint of wheel rotation has the particular actuators employed during a braking event determined, at least in part, by monitored wheel motion. The system (30) reduces brake energy consumption and heat generation during slow speed operations, reduces braking induced vibration, and compensates for individual actuator failure.

Abstract: The adaptive brake application and initial skid detection system allows rapid brake application and prevents deep initial skids. Brake pressure is compared with a predetermined threshold brake pressure. Wheel velocity error signals are also generated to indicated the difference between the wheel velocity and a reference velocity signal. A pressure bias modulator integrator responsive to brake pressure signals adjusts the wheel velocity error signals to provide an anti-skid control signal. The pressure bias modulator integrator can also be initialized to the value of the measured brake pressure when the wheel velocity error signals indicate the beginning of a skid. Brake pressure difference signals are generated to indicate the difference between brake pressure and a commanded brake pressure, and an adjusted brake pressure error signal is generated in response to the brake pressure difference signals.

Abstract: A redundant brake control and anti-skid system is described for providing braking to a vehicle. The system includes a primary brake control assembly for performing brake control and anti-skid functions, and a secondary brake control assembly for performing brake control and anti-skid functions. A bus is provided for enabling communications between the primary brake control assembly and the secondary brake control assembly. At least one brake actuator controlled by the primary brake control assembly and at least one other brake actuator controlled by the secondary brake control assembly are included for providing braking force to wheels of the vehicle.

Abstract: The adaptive brake application and initial skid detection system allows rapid brake application and prevents deep initial skids. Brake pressure is compared with a predetermined threshold brake pressure. Wheel velocity error signals are also generated to indicated the difference between the wheel velocity and a reference velocity signal. A pressure bias modulator integrator responsive to brake pressure signals adjusts the wheel velocity error signals to provide an anti-skid control signal. The pressure bias modulator integrator can also be initialized to the value of the measured brake pressure when the wheel velocity error signals indicate the beginning of a skid. Brake pressure difference signals are generated to indicate the difference between brake pressure and a commanded brake pressure, and an adjusted brake pressure error signal is generated in response to the brake pressure difference signals.

Abstract: In a braking system including a plurality of independently operable hydraulic brake assemblies, a controller is provided for monitoring the hydraulic pressure at at least some of the brake assemblies and for comparing that pressure with a brake control demand signal so that all or substantially all brake assemblies can be brought into operation if that comparison indicates a requirement for additional or full braking operation.

Abstract: The invention relates to apparatus for braking a set of aircraft wheels, the apparatus comprising a normal hydraulic circuit and an emergency hydraulic circuit, both circuits leading to each of the various brakes via associated brake valves. According to the invention, the brake valves of the normal circuit and/or of the emergency circuit are constituted by direct drive valves that are electrically controlled by an associated electronic control unit.

Abstract: A brake-by-wire control system for aircraft brakes is presented. The system includes a hardware based discrete component control path and a software control path, the two operating in parallel. Each of the paths monitors the same input, with the hardware path being configured to enable the shutoff valve driver and the software path being configured to inhibit the shutoff valve driver, depending upon the status of the inputs. As a consequence, a failure in a single path in the braking system cannot enable the brake system so as to allow for inadvertent braking.

Abstract: An antiskid brake controller which utilizes measured wheel speed in order to provide brake control for a vehicle such as an aircraft. The measured wheel speed is differentiated to determine the deceleration of the wheel, and the controller then compares the deceleration to a predefined deceleration threshold. If the wheel decelerates faster than the deceleration threshold, the controller reduces the command pressure provided to the brakes by a scaling factor. Full command pressure may eventually be applied otherwise. The controller is capable of operating based only on measured wheel speed.

Abstract: At low speeds, an antiskid/autobrake control system applies a brake release current to the antiskid valves of the brake system associated with selected wheels of an airplane to prevent brake shudder caused by gear walk. The control system obtains a measured wheelspeed value from each of the selected wheels and calculates a reference wheelspeed based the measured wheelspeed. Tests are made to determine if the reference wheelspeed is below some predetermined magnitude, e.g., 15 knots, and if the airplane ground speed is below some predetermined magnitude, e.g., 50 knots. If the tests are passed, the value of a low-speed brake release current to be applied to the antiskid valves of the airplane's brake system is determined. In order to prevent an abrupt change in braking, the low-speed brake release value ramps off as the airplane slows to a stop. Releasing some of the brakes results in the pilot increasing pressure on the remaining brakes, thereby eliminating brake shudder due to gear walk.

Abstract: An antiskid control system for aircraft braking consisting of an iterative system having inputs including wheel speed, time since touchdown and the value of the control current generated by the previous iteration. Utilizing the previous value and applying fuzzy logic rules, the system modifies itself to adjust for variations in the coefficient of friction between the wheels and the runway.

Abstract: A brake system and torque feedback controller is provided which utilizes low torque cutout rather than low speed cutout. The low torque cutout is further improved by gradually transitioning between torque feedback and open loop control over a range of torque. The controller allows torque compensation operation to zero wheel speed, and avoids discontinuities in braking regardless of time or torque level. The controller allows a brake to fill and engage the wheel before the full feedback signal is presented to the controller so as to eliminate the phenomena of grabby brakes.

Abstract: In an aircraft braking system comprising a plurality of carbon brakes a brake control system is provided whereby the number and/or proportion of brakes that may be disabled at each stage of a flight spectrum (i.e. taxi-out, take-off, in-flight, landing, taxi-in or stationary on the ground) and also the number and/or proportion applicable during each stage is further adjusted in response to the specific conditions applicable to the aircraft status at any given time thereby to ensure that the overall safety of the aircraft is not hazarded. The operation of the brake control system may be controlled at least in part by an on-board brake control implementation device actuated by a remote, land-based signal. The brake control system providing for use of less than the total number of available brakes during the landing stage of the flight spectrum.

Abstract: Enhanced directional stability in an aircraft anti-skid braking system is achieved by using one common deceleration command (16) which is a selected one of left and right brake pedal deceleration commands (19, 119). The individual brake pedal deceleration commands (19, 119) are used to modify (34, 134) the common or selected deceleration command (16) and provide respective side wheel velocity commands to retain a differential braking capability (36, 136), and thereby avoid the potential for instability inherent when utilizing individual deceleration commands for the left and right wheel brakes of an aircraft.