Abstract: An aircraft brake control system accommodates desired yaw for steering, while substantially eliminating undesired yaw. The system assesses brake command signals from the pilot, signals corresponding to aircraft parameters, and signals based on brake control parameters, and determines therefrom an amount of yaw desired by the pilot. The instantaneous yaw rate is monitored and compared to the desired yaw rate. An error signal corresponding to the difference between instantaneous and actual yaw rates is calculated and that error signal is employed to modify a braking differential between right and left brakes to eliminate or substantially reduce the undesired yaw.

Abstract: A system and associated method for achieving both force and position control of motor-driven electrical brake actuators for a brake disc stack that has, and seeks to maintain, a characteristic built-in clearance among the discs. The system employs both force feedback and motor turns position feedback associated with the actuator during a braking operation in order to obtain a motor turns position that achieves the characteristic built-in clearance following braking action or the like.

Abstract: A method of diagnosis and prognosis for various operative systems is provided so that maintenance can be efficiently and effectively scheduled and provided. The invention is applicable to a broad range of systems, but particularly to aircraft brake systems and tires. An aircraft brake may be modeled by attributing brake wear factor values to various parameters associated with the aircraft brake that impact wear. Over the course of time and during braking events, the brake wear factor values are summed and a running total of that sum is kept over the life of the brake. At a point in time when the sum of weighted factors exceeds a preset threshold, an indicia is generated that service is required.

Abstract: Various embodiments of aircraft brake assembly structures are provided for achieving noise reduction during braking activity. In certain embodiments of the invention, the actual application of force to the pressure plate is regulated such that a different number of actuator pistons are used during low-energy stops than during high-energy stops. In other embodiments of the invention, the pressure plate or endplate is augmented as to surface area in some instances and as to a taper angle in others, again to achieve a desired increase in effective pressure application during low-energy stops. In other embodiments of the invention, the stator and/or rotor disks are characterized by slots to break up the propagation of noise waves.

Abstract: A flexible wheel drive for aircraft onboard taxi systems is provided. In association with an aircraft wheel assembly there is provided a drive gear assembly that is adapted to be driven by a motor mounted to an aircraft. A flexible drive flange is secured about an inboard rim of the aircraft wheel assembly and a flexible ring is interconnected between the drive gear assembly and the flexible drive flange. Preferably, the flexible ring is made of a metal textile or high-temperature composite and the drive flange is of a high-strength stainless steel.

Abstract: An electric brake power conversion and distribution system for use in aircraft is provided. An array of DC-DC converters is interposed between a DC power source and a plurality of aircraft electric brake actuators. Each of the DC-DC converters has a characteristic output voltage. The DC-DC converters are interconnected in an additive series of connections to provide an output voltage to the plurality of aircraft electric brake actuators that comprises the sum of the characteristic voltages of the DC-DC converters that are enabled at a particular point in time. A controller manipulates an array of switches interconnected with the array of DC-DC converts, such that the controller can selectively enable or inhibit selected ones of the DC-DC converters, as desired. Accordingly different voltages can be made available for the electric brake actuators depending upon aircraft activity, such as landing, taxiing, parking, or in flight.

Abstract: An electric aircraft brake control system has a plurality of wheel and brake assemblies, each having a wheel, wheel speed transducer, brake assembly and a brake actuator. Electromechanical control units are uniquely associated with and connected to certain of the wheel and brake assemblies, and each of the electromechanical control units is provided with an antiskid system as an integral portion thereof. Brake data concentrators are provided for receiving data corresponding to various aircraft operational parameters, including brake pedal position, and provide operational signals to the electromechanical control unit as a function thereof. A controller for emergency and park braking is connected to the electromechanical actuator controllers through one of the brake data concentrators to effect emergency braking action on the brake assemblies, such emergency braking action having incident antiskid control.

Abstract: A heat shield segment includes at least one tab extending from an outboard end, the tab adapted to secure the heat shield segment against radial and axial movement. The at least one tab is received over a retaining ring positioned within a tube well of a wheel. The retaining ring is received in recesses formed in the inner surface of drive keys spaced around the interior of the tube well. The heat shield segment is secured at the inboard end by a fastener, and is spaced from the tube well by a spacer positioned between the heat shield segment and the tube well. The at least one tab of the heat shield segment allows for easy assembly and maintenance of the heat shield assembly formed by a plurality of the heat shield segments.

Abstract: A balanced brake control system is provided for use in aircraft. An embodiment of the invention is presented for an aircraft having struts with both inboard and outboard braked wheels on the struts. In the detailed embodiment, an equalizer circuit is interposed between right and left brake pedals on an input side thereof and right and left inboard and outboard brakes on an output side thereof. This equalizer circuit ensures a first equal application of brake pressure to the right inboard and outboard brakes and a second equal application of brake pressure to the left inboard and outboard brakes, dependent upon pilot control of brake pedals. The first and second equal applications of brake pressure may differ to accommodate differential braking.

Abstract: A brake housing and torque tube assembly for a vehicle such as an aircraft is presented. The interface between the brake housing and the torque tube is accommodated by a thermal composite material insulator that is located adjacent the brake housing and a metallic spacer adjacent the torque tube. The metallic spacer provides stiffness to the joint therebetween to prevent fatigue failure of the bolts interconnecting the brake housing and the torque tube. The metallic spacer also protects the insulator ring from sharp edges and small bearing area that are typically present at the ends of the torque tube.

Abstract: An electric brake actuator for the brake system of an aircraft is presented. A brake actuator includes a piston driven by a cylindrical nut and screw arrangement, driven by an appropriate motor of the actuator. Application of brake force results in a reactionary force that deflects the top cover of the actuator. The axial component of this deflection correlates directly with the brake force applied. A beam is interposed between this cover and a top cap, such that deflection of the beam correlates to applied brake face. Piezo-resistive devices are connected to the beam and, through a whetstone bridge, provide an electrical output signal correlating to applied brake force.

Abstract: A method and apparatus for making carbon/carbon composite disks for braking applications that employs a continuous feeding of fiber strands into a mold. The fibers are then compressed to form a mat or preform. The fibers are then needled such that the fibers within the mat interlock and extend in various directions. The mat or preform is then subjected to densification processing. In order to enhance the effectiveness of the densification process and/or to speed up the processing time, a filler is added to the preform during the manufacturing process. The fillers are added by way of a dry powder or as a liquid slurry. The filler may be aluminum oxide, boron carbide, silicon carbide, pitch, or a variety of carbonic or noncarbonic performance enhancers.

Abstract: A process for fabricating a carbon composite structure that is lightweight, structurally sound, and characterized by high heat capacity. A carbon structure is devised with cavities therein receiving a phase change medium. The phase change medium demonstrates both high energy absorption capacity and high thermal conductivity and is formed from a carbon fiber to establish a high porosity medium having a large volume fraction. The surface energy of the carbon fibers is enhanced in various ways as by deposition of a carbide former, a metallurgical coating or a precursor liquid or by electroplating or etching the surfaces of the carbon fibers. The enhanced surface energy allows for the retention of phase change material.

Abstract: A brake control system for a wheeled vehicle includes a field programmable gate array configured to perform the algorithm of brake control subsystems in a typical brake control system for a wheeled vehicle. The brake control subsystems typically include anti-skid control, brake temperature monitoring, built-in tests, and, in the case of an aircraft, nose wheel steering. The system also includes wheel speed sensors, brake temperature monitors, brake valves and associated control circuits, and brake valve monitors respecting brake valve current and voltage. The use of field programmable gate arrays to configure a brake control system avoids the obsolescence and shortened life of control systems previously dependent upon microprocessors and the like.

Abstract: A torque tube and conical back plate for aircraft brakes including a torque tube having a truncated back plate of thin metal construction extending from the outboard end thereof. The conical back plate is characterized by inner and outer reinforcing rings, such rings providing a compressive force at opposite ends of the truncated cone of the back plate, thus allowing the back plate to resist bending and deflection. In accordance with the invention, the cross sectional centers of mass of the inner and outer reinforcing rings are shifted outboard from a projection of the center plane of the conical back plate, such positioning enhancing the stiffening and reinforcing capabilities of the reinforcing rings.

Abstract: A torque tube and conical back plate for aircraft brakes including a torque tube having a truncated back plate of thin metal construction extending from the outboard end thereof. The conical back plate is characterized by inner and outer reinforcing rings, such rings providing a compressive force at opposite ends of the truncated cone of the back plate, thus allowing the back plate to resist bending and deflection. In accordance with the invention, the cross sectional centers of mass of the inner and outer reinforcing rings are shifted outboard from a projection of the center plane of the conical back plate, such positioning enhancing the stiffening and reinforcing capabilities of the reinforcing rings.

Abstract: Apparatus for aircraft brake thermal management including heat shields made of one or more insulating pouches of metallic foil having ceramic fibers or other appropriate insulation therein. The pouches are either vacuum sealed or provided with pin hole breathing apertures to eliminate expansion forces, while precluding the entry of cleaning fluids, moisture and the like into the cavity thereof. The invention further provides for brake rotor and stator disks having lugs of increased shear strength, while providing cooling apertures or slots therein. Finally, the invention includes a heat shield interposed between an aircraft wheel and the brake disk stack, and wherein the heat shield is flared at an end thereof to maximize the ingress and egress of cooling air to optimize aircraft turnaround time.

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: A method and apparatus for making carbon/carbon composite discs for an aircraft brake employs a continuous feeding of fiber strands into a mold. Water is then combined with the fibers and the fibers are compressed to form a moisturized mat or preform. The fibers are then needled such that the fibers within the mat or preform extend in radial, circumferential, and axial directions. The mat or preform is then subjected to densification. The resulting disc is of total carbon construction. The water introduced into the mat during the processing serves as both a sacrificial binder and a lubricant during the fabrication.

Abstract: A beam key and wheel assembly for aircraft brakes is presented. A beam key is pinned at one end to the aircraft wheel and is engaged proximate an opposite end to a pad on an outrigger flange of the wheel. The pad has a milled arcuate surface which is congruent with and nestingly receives a similar arcuate surface of a foot member. The foot has a channel formed therein on a side opposite the arcuate surface, the channel matingly receiving a base on a bottom surface of the beam key. A bolt passes through the beam key, foot, and pad on the outrigger flange to secure the elements together.