Abstract: A system for determining brake wear based on hydraulic fluid volume may comprise a brake actuator and a fluid supply line fluidly coupled to the brake actuator. The brake actuator may include a brake ram configured to translate in response to changes in fluid pressure in the brake actuator. A piston may be fluidly coupled between a first portion of the fluid supply line and a second portion of the fluid supply line. The piston may include a cylinder and a ram configured to translate within the cylinder. A first sensor may be operably coupled to the piston.

Abstract: A method for active brake selection, in accordance with various embodiments is disclosed. The method comprises detecting an outbound taxiing event for an aircraft. The method further comprises determining whether an inboard or outboard brake has less wear than a respective inboard or outboard brake on a respective landing gear. The method may further comprise selecting an inboard or outboard brake to use during the outbound taxiing event.

Abstract: A system for determining brake wear based on hydraulic fluid volume may comprise a brake actuator and a fluid supply line fluidly coupled to the brake actuator. The brake actuator may include a brake ram configured to translate in response to changes in fluid pressure in the brake actuator. A piston may be fluidly coupled between a first portion of the fluid supply line and a second portion of the fluid supply line. The piston may include a cylinder and a ram configured to translate within the cylinder. A first sensor may be operably coupled to the piston.

Abstract: Systems and methods for tuning power transmission circuits may sweep a power frequency applied to a transmission coil across a plurality of frequencies. The transmission coil may be inductively coupled to a receiving coil and separated from the receiving coil by an air gap. A current and/or voltage at the transmission coil may be measured in response to the power frequency being at each frequency of the plurality of frequencies. A transmission frequency may be selected based at least in part on the measured current and/or the measured voltage.

Abstract: Systems and methods for a bi-stable valve are provided. The bi-stable valve may comprise a housing including an input port, a first output port, and a second output port, a spool disposed within the housing and configured to translate in response to a first magnetic force, wherein the spool is further configured to selectively enable fluid communication between the input port and each of the first output port and the second output port in response to translating the spool between a first position and a second position, a spring disposed within the housing and coupled to the spool, an electromagnet coupled to the housing and configured to apply the first magnetic force to the spool, and a permanent magnet configured to apply a second magnetic force to the spool.

Abstract: A method for active brake selection, in accordance with various embodiments is disclosed. The method comprises detecting an outbound taxiing event for an aircraft. The method further comprises determining whether an inboard or outboard brake has less wear than a respective inboard or outboard brake on a respective landing gear. The method may further comprise selecting an inboard or outboard brake to use during the outbound taxiing event.

Abstract: Systems and methods for a bi-stable valve are provided. The bi-stable valve may comprise a housing including an input port, a first output port, and a second output port, a spool disposed within the housing and configured to translate in response to a first magnetic force, wherein the spool is further configured to selectively enable fluid communication between the input port and each of the first output port and the second output port in response to translating the spool between a first position and a second position, a spring disposed within the housing and coupled to the spool, an electromagnet coupled to the housing and configured to apply the first magnetic force to the spool, and a permanent magnet configured to apply a second magnetic force to the spool.

Abstract: A method of performing prognostics on a hydraulic brake system of an aircraft may include determining, during primary braking mode and by a hydraulic brake controller, a first status of a first brake pressure sensor adjacent a brake assembly. The method may also include, in response to determining that the first status of the first brake pressure sensor is valid, determining, during park braking mode and by the hydraulic brake controller, a second status of a second brake pressure sensor adjacent a park valve assembly. In response to determining that the first status of the first brake pressure sensor is degraded, the method may include outputting, by the hydraulic brake controller, at least one of an inspection indicator and a maintenance indicator.

Abstract: Braking control systems and methods, such as for an aircraft, use a dump valve to rapidly decrease hydraulic pressure applied to a brake actuator during a wheel skid condition. In response to the wheel speed recovering, the dump valve is commanded closed and the brake control system returns to normal braking. The dump valve and a servo-valve may work harmoniously for locked wheel brake control.

Abstract: A wheel speed sensor may comprise a magnet; an induction coil coupled to the magnet; a rotor comprising a plurality of teeth, wherein the magnet is disposed proximate the plurality of teeth; a gear system coupled to the rotor comprising an initial gear, wherein the initial gear may be configured to be coupled to a wheel and configured to rotate at a speed equal to a wheel rotational speed of the wheel. The gear system may be configured to cause a rotor rotational speed of the rotor to be greater than the wheel rotational speed in response to the wheel rotating.

Abstract: Systems and methods for detecting wheel speed are provided. An electric circuit for detecting a speed of a wheel may comprise: a transducer in electronic communication with an operational amplifier (OP-AMP), the transducer configured to output a variable signal in response to an angular velocity of a rotatable member of a wheel assembly; a constant voltage source in electronic communication with the OP-AMP; and a sensor in electronic communication with an output terminal of the OP-AMP configured to monitor an output signal of the OP-AMP, the output signal including a period; and a controller configured to receive the output signal and configured to calculate the speed of the wheel according to a pre-determined ratio of the wheel speed and the period. In various embodiments, the circuit may allow for slow wheel speed detection.

Abstract: Braking control systems and methods, such as for an aircraft, use a dump valve to rapidly decrease hydraulic pressure applied to a brake actuator during a wheel skid condition. In response to the wheel speed recovering, the dump valve is commanded closed and the brake control system returns to normal braking. The dump valve and a servo-valve may work harmoniously for locked wheel brake control.

Abstract: A brake control system may comprise an inertial sensor coupled to an axle and configured to measure a linear acceleration of the axle and an antiskid control (ASK) in electronic communication with the inertial sensor, wherein at least one of the inertial sensor or the ASK calculate a linear velocity of the axle based on the linear acceleration, and the ASK uses the linear velocity to calculate a wheel slip speed.

Abstract: Systems and methods for tuning power transmission circuits may sweep a power frequency applied to a transmission coil across a plurality of frequencies. The transmission coil may be inductively coupled to a receiving coil and separated from the receiving coil by an air gap. A current and/or voltage at the transmission coil may be measured in response to the power frequency being at each frequency of the plurality of frequencies. A transmission frequency may be selected based at least in part on the measured current and/or the measured voltage.

Abstract: Braking control systems and methods, such as for an aircraft, use a first pressure sensor and a second pressure sensor from a non-primary braking system to validate the first pressure sensor. In response to the first pressure sensor being validated, a health status of a servo valve is monitored based on predetermined characteristics about the servo valve, including electrical current input into the servo valve and hydraulic pressure output from the servo valve.

Abstract: Systems and methods for tuning power transmission circuits may sweep a power frequency applied to a transmission coil across a plurality of frequencies. The transmission coil may be inductively coupled to a receiving coil and separated from the receiving coil by an air gap. A current and/or voltage at the transmission coil may be measured in response to the power frequency being at each frequency of the plurality of frequencies. A transmission frequency may be selected based at least in part on the measured current and/or the measured voltage.

Abstract: A method of performing prognostics on a hydraulic brake system of an aircraft may include determining, during primary braking mode and by a hydraulic brake controller, a first status of a first brake pressure sensor adjacent a brake assembly. The method may also include, in response to determining that the first status of the first brake pressure sensor is valid, determining, during park braking mode and by the hydraulic brake controller, a second status of a second brake pressure sensor adjacent a park valve assembly. In response to determining that the first status of the first brake pressure sensor is degraded, the method may include outputting, by the hydraulic brake controller, at least one of an inspection indicator and a maintenance indicator.

Abstract: A BCU for determining a health status of a LRU having a coil includes a non-transitory memory configured to store instructions and a controller coupled to the non-transitory memory. The controller is designed to receive a temperature from a temperature sensor, to receive a direct current (DC) voltage that is applied to the coil of the LRU, and to receive a detected current corresponding to an amount of current flowing through the coil. The controller is further designed to determine a calculated resistance of the coil based on the detected current and the DC voltage and to determine a compensated resistance of the coil based on the temperature and the calculated resistance of the coil. The controller is further designed to determine the health status of the LRU by comparing the compensated resistance of the coil to a nominal resistance of the coil.

Abstract: Braking control systems and methods, such as for an aircraft, use a first pressure sensor and a second pressure sensor from a non-primary braking system to validate the first pressure sensor. In response to the first pressure sensor being validated, a health status of a servo valve is monitored based on predetermined characteristics about the servo valve, including electrical current input into the servo valve and hydraulic pressure output from the servo valve.

Abstract: A BCU for determining a health status of a LRU having a coil includes a non-transitory memory configured to store instructions and a controller coupled to the non-transitory memory. The controller is designed to receive a temperature from a temperature sensor, to receive a direct current (DC) voltage that is applied to the coil of the LRU, and to receive a detected current corresponding to an amount of current flowing through the coil. The controller is further designed to determine a calculated resistance of the coil based on the detected current and the DC voltage and to determine a compensated resistance of the coil based on the temperature and the calculated resistance of the coil. The controller is further designed to determine the health status of the LRU by comparing the compensated resistance of the coil to a nominal resistance of the coil.