Abstract: In one embodiment, a system determines activation parameters for an autonomous driving vehicle (ADV), where the activation parameters include historical usages of a primary brake system or a secondary brake system. In response to determining that a brake is to be applied, the system determines whether to activate a primary or a secondary brake system based on the activation parameters. The system sends an activation flag to activate the primary or the secondary brake system based on the determining whether to activate the primary or the secondary brake system. The system sends a brake command to the primary and the secondary brake system to activate either the primary or the secondary brake system according to the activation flag.

Abstract: A method of controlling torque in an all-wheel-drive vehicle limits the duration of loss of traction. During wheel slip events, a controller reduces the commanded torque from a driver demanded level. The controller calculates a normalized wheels speed for each wheel based on a measured yaw rate, measured wheel speeds, and calculated wheel diameters. The controller determines the end of the wheel slip event by comparing the normalized speeds of each while to one another.

Abstract: Method and apparatus for wheel speed estimation include an electrical powertrain having an electric motor providing a motor speed, a wheel, and a mechanical coupling between the motor and the wheel, and an electronic control unit calculating an estimated wheel speed based on the motor speed and mechanical dynamic models of the electrical powertrain.

Abstract: An apparatus and a method for estimating a road surface friction coefficient relate to an apparatus of estimating a road surface friction coefficient including an additional power control module that arbitrarily adds a braking force, which causes a wheel speed difference, to an axle of the vehicle to which the braking force is applied, and together adds a driving force that cancels the braking force to an axle of the vehicle to which the driving force is applied, when it is determined that a driving state of the vehicle is an inertial driving state, and a road surface friction coefficient estimation module that estimates the road surface friction coefficient by the wheel speed difference caused by a newly added braking force.

Abstract: A device for a hydraulic braking system of a vehicle. The device includes a processing unit, which is programmed to determine at least one brake characteristic value of the hydraulic braking system, the processing unit being programmed to determine the at least one brake characteristic value as a vehicle axle-specific brake characteristic value, which in each case corresponds to a ratio between a brake pressure in all wheel brake cylinders assigned to a shared vehicle axle of the vehicle and a vehicle axle braking torque exerted on the shared vehicle axle with the aid of the wheel brake cylinders. A method for determining at least one brake characteristic value of a hydraulic braking system of a vehicle, and a method for decelerating a vehicle with a hydraulic braking system and an electric motor usable as a generator, are also described.

Abstract: A method for processing friction data for vehicle tires on road segments, implemented by a processing system including at least one computer and an interface for remote communication with a plurality of vehicles, the method including: acquiring, from the plurality of vehicles, friction data for tires of the vehicles on a plurality of road segments, each friction datum including at least: a maximum coefficient of friction available to the vehicle on the road segment, and information relating to the road segment; establishing, for each road segment, a distribution of the friction data obtained from the plurality of vehicles for the road segment; and determining a plurality of road types, each road type comprising a set of road segments, from a measurement of similarity between the distributions of friction data obtained for each road segment.

Abstract: A highly reliable vehicle brake system that includes an electric brake and achieves redundancy at low cost is provided. A vehicle brake system (1) is provided to a wheel (Wa) of a vehicle (VB), and includes an electric brake (16a) provided with a motor (80), a driver (60) that drives the motor (80), and a first control device (10) provided with a master controller (30) and a first sub-controller (40) connected to each other. The electric brake (16a) is controllable by both the master controller (30) and the first sub-controller (40).

Abstract: A method for estimating the temperature of a component being monitored is described herein, comprising: inputting data related to the component being monitored into a brake thermal model; using the brake thermal model to predict a temperature of the component based on the input data; inputting a) actual temperature sensor measurement data of the component and b) the predicted temperature into an estimation algorithm, wherein the estimation algorithm combines the a) actual temperature sensor data and b) predicted temperature and generates an estimated brake temperature of the component based on the combined inputs. A computer-implemented system is also described.

Abstract: A brake actuator comprising a DC motor, a computer configured for: measuring, over time, a current drawn by the motor and a voltage between the terminals of the motor; implementing a Kalman filter in order to compute, from the measured current and voltage, a filtered current drawn by the motor and a filtered rotational speed of a shaft of the motor; computing, from the value of the filtered current and the value of the filtered rotational speed, a clamping force that is produced by the actuator; controlling the motor such that it stops when the computed value of the clamping force reaches a predetermined setpoint value.

Abstract: An autonomous driving control device includes: a plurality of control devices that each have a first storage unit and a processing unit; a load control unit; a second storage unit; and a failure detection unit. The programs include autonomous driving programs and other programs. When a failure is detected, the load control unit unloads at least some of the other programs from the first storage unit of a normal control device, and loads the autonomous driving program corresponding to that loaded in the first storage unit of a failed control device from the second storage unit into the first storage unit of the normal control device.

Abstract: A rewriting process of data stored in a control device is performed while executing a normal process. In a control system including a plurality of control devices in which data have been stored, each of which is a device for controlling an electric component of an automobile, a first communication line interconnecting the plurality of control devices, and a second communication line interconnecting the plurality of control devices for hacking up the first communication line, a rewriting device in which rewriting data have been stored is connected to the second communication line, and the rewriting device rewrites data stored in the control device to be rewritten with the rewriting data based on the rewriting data using the second communication line.

Abstract: Systems and methods are provided for generating data indicative of a friction associated with a driving surface, and for using friction data as part of controlling autonomous vehicle operations. In one example, a computing system can detect an event including at least one of an acceleration, a deceleration, or a stop associated with an autonomous vehicle and obtain, in response to detecting the event, operational data associated with the autonomous vehicle during the event. The computing system can determine, based at least in part on the operational data, data indicative of a friction associated with a surface upon which the autonomous vehicle is traveling during the event. The computing system can control the autonomous vehicle based at least in part on the data indicative of the friction associated with the surface.

Abstract: A system and method for estimating a wheel speed of a vehicle are provided. The system includes a wheel speed sensor that detects a rotation speed of a wheel of the vehicle and a longitudinal acceleration sensor that detects a longitudinal acceleration of the vehicle. A controller converts the longitudinal acceleration to a wheel acceleration, compensates for the converted wheel acceleration based on a compensation value obtained using wheel speed information, integrates the compensated wheel acceleration, and calculates a wheel speed estimation value based on the integrated wheel acceleration.

Abstract: The invention i.a. relates to a load transfer arrangement (10) for a vehicle (12) including a chassis (14) with at least one braked axle (16), the arrangement (10) comprising: a non-driven load axle (18), and an air suspension assembly (20) including at least one air cushion (22) arranged between the chassis (14) and the non-driven load axle (18) in order to transfer load from the braked axle(s) (16) to the non-driven load axle (18), wherein the non-driven load axle (18) is unbraked, and wherein the arrangement (10) further comprises: an evacuation controller (24) configured to provide a pressure release trigger in response to a current or predicted braking event of the vehicle (12), and at least one evacuation valve (26) configured to, in response to receiving the pressure release trigger, evacuate pressure from the at least one air cushion (22) in order to remove load from the non-driven load axle (18) and increase load on the braked axle(s) (16).

Abstract: A vehicle control device includes sensors that detect pulse signals corresponding to rotation of front wheels and of rear wheels of a vehicle, and a controller that increases a count at a rise and a fall of the pulse signals. The controller estimates a road surface friction coefficient based on a time rate of change of a difference between a value counted up using the front wheels and a value counted up using the rear wheels.

Abstract: Method and apparatus are disclosed for traction control based on friction coefficient estimation. An example vehicle includes a plurality of sensors to measure qualities of a surface of a road and an anti-lock brake system module. The anti-lock brake system module (a) estimates confidence values for different road surface types based on the qualities of the surface of the road, (b) estimates a coefficient of friction between the road and tires of the vehicle based on the confidence values, and (c) adapt a traction control system by altering a target slip based on the coefficient of friction.

Abstract: A brake control system for a landing gear of an aircraft is provided. The system includes a first control channel for providing brake control signals to one or more brakes on the landing gear, and a second control channel for providing brake control signals to another one or more brakes on the landing gear. At least one of the first control channel and the second control channel is configured to act as an executive in monitoring braking efforts applied by the one or more brakes as compared to braking efforts applied by the another one or more brake, and to cause the braking efforts of at least one of the one or more brakes or the another one or more brakes to be modified in an effort to equalize the braking efforts.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A drive system includes a power converter and a motor powered from the power converter via supply leads. An electromagnetically actuatable brake is disposed on the motor. The brake is able to be supplied and is therefore controllable from an AC/DC converter, which is powered via lines from a DC/AC converter that is powered and/or controlled by signal electronics of the power converter.

Abstract: An outboard motor includes an outboard motor main body, a mount, a turning mechanism, an electric actuator, and a controller. The mount attaches the outboard motor main body to a hull. The outboard motor is turnable around a tilt shaft. The turning mechanism turns the outboard motor main body around the tilt shaft to incline the outboard motor main body. The electric actuator supplies a driving force to the turning mechanism. The outboard motor includes an inclination angle sensor that detects an inclination angle of the outboard motor main body. The controller energizes the electric actuator in response to an operation switch and performs energization limiting control to limit energization of the electric actuator when a magnitude of a rate of change of the inclination angle is equal to or less than a predetermined determination threshold for a predetermined duration of time.

Abstract: An in-vehicle production lighting system includes: an acceleration sensor configured to detect an acceleration of a vehicle; light emitters arranged at a prescribed position in a cabin of the vehicle and capable of changing light intensity and light color in a prescribed lighting pattern; and a controller configured to generate or select the prescribed lighting pattern depending on a detection result obtained by the acceleration sensor and control the light emitters.

Abstract: A road load module is configured to determine a road load torque to maintain zero vehicle acceleration. An initialization module is configured to determine an initial torque based on the road load torque. A closed loop (CL) module is configured to: when a CL state transitions from an inactive state to an active state, set a CL torque to the initial torque; and when the CL state is in the active state after transitioning to the active state, adjust the CL torque based on a difference between a target vehicle speed and a vehicle speed. A motor torque module is configured to determine a motor torque command based on the CL torque and a motor torque request determined based on an accelerator pedal position. A switching control module is configured to, based on the motor torque command, control switching of an inverter and apply power to an electric motor.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A driver assistance apparatus for a vehicle may be provided with Idle Stop and Go (ISG), and the driver assistance apparatus may include: an interface configured to receive information; and a processor. The processor may be configured to: receive, through the interface, driving information of the vehicle; and based on a determination that the vehicle is stopped in a first state in which the ISG is enabled or that the vehicle is stopped in a second state in which a gearshift of the vehicle is engaged in a Park (P) mode and an engine of the vehicle is turned on, perform a stopping operation for the vehicle based on the driving information of the vehicle.

Abstract: An embedded modem communicates over a vehicle bus with controllers that each include data storage. The embedded modem queries the controllers over the bus to identify controllers having available storage, such that if the available storage is located on a priority controller, the embedded modem sends received data over the bus to the priority controller. Otherwise, if the available storage is available on a non-priority controller, the embedded modem send the data over the bus to the non-priority controller. The embedded modem queries the controllers over the bus to confirm that the controllers storing the received data are available for data offload, and responsive to the confirmation, requests the stored data over the bus and transmits the stored data over a wide-area network to a telematics server.

Abstract: Various embodiments of an apparatus and method for monitoring a brake operation are disclosed. In accordance with one aspect, the brake operation monitoring system comprises a plurality of wheel speed sensors, a brake demand sensor; a plurality of stability sensors and a controller. The controller comprises wheel speed ports; a brake demand port; stability sensor ports; a communication port for receiving a plurality of messages; and a processing unit comprising control logic. The control logic receives a brake demand signal, at least one stability signal indicative of the cornering of the vehicle, and individual wheel speeds. The control logic calculates a master value to compare to individual wheel speed signals if the brake demand signal indicates no braking.

Abstract: The vehicular brake system includes a hydraulic brake device and an electromechanical brake device. The electromechanical brake device includes: an electric motor; a braking force application mechanism to apply, to wheels, a braking force having a value based on an output from the electric motor; and a control device to control the electric motor. A brake operation input detector to detect an input of a brake operation is provided. The control device includes: determination section to determine whether a vehicle speed detected by vehicle speed detector is less than or equal to a predetermined vehicle speed; and operation limiter to limit or halt an output from the electric motor even when the brake operation input detector detects an input of a brake operation in a case where the determination section determines that the vehicle speed is less than or equal to the predetermined vehicle speed.

Abstract: A hill-hold control system for a vehicle. The hill-hold control system includes a first wheel brake (120A, 120B), a second wheel brake (120C, 120D), a braking indicator (brake pedal), a drive away indicator (accelerator), and a controller (130). The controller is configured to determine that the vehicle is at standstill, detect from the braking indicator that braking is no longer desired, adjust a braking pressure at the first wheel brake, adjust a braking pressure at the second wheel brake, detect from the drive away indicator an operator's desire to drive away, and when the operator's desire to drive away is detected, removing the braking pressure at the first wheel brake and the braking pressure at the second wheel brake.

Abstract: A vehicle electric braking device wherein: a first degree of contribution associated with the actual pressing force value and a second degree of contribution associated with an estimated pressing force value, are determined based on operation amount of a braking operation member; the second degree of contribution is determined to be larger than the first degree when the operation amount is small; the first degree of contribution is determined to be larger than the second when the operation amount is large; a combined pressing force is calculated based on a value obtained by accounting for the first degree of contribution in the actual pressing force value and a value obtained by accounting for the second degree of contribution in the estimated pressing force value; and an electric motor target power supply amount is calculated based on the combined pressing force and a target pressing force calculated from the operation amount.

Abstract: A braking system for a machine includes a first valve assembly having a first electronically actuated proportional valve, and a second valve assembly having a second electronically actuated proportional valve. The braking system includes a first pressure sensor and a second pressure sensor disposed downstream of the first and second valve assemblies, respectively. The first and second pressure sensors are configured to determine a first pressure and a second pressure of a braking fluid from the first and second valve assembly. The braking system also includes a controller configured to receive a signal indicative of the first pressure and the second pressure of the braking fluid and compare the first pressure and the second pressure. The controller is configured to selectively actuate at least one of the first electronically actuated proportional valve and the second electronically actuated proportional valve to substantially equalize the first pressure and the second pressure.

Abstract: Various embodiments of an apparatus and method for monitoring a brake operation are disclosed. In accordance with one aspect, the brake operation monitoring system comprises a plurality of wheel speed sensors, a brake demand sensor; a plurality of stability sensors and a controller. The controller comprises wheel speed ports; a brake demand port; stability sensor ports; a communication port for receiving a plurality of messages; and a processing unit comprising control logic. The control logic receives a brake demand signal, at least one stability signal indicative of the cornering of the vehicle, and individual wheel speeds. The control logic calculates a master value to compare to individual wheel speed signals if the brake demand signal indicates no braking.

Abstract: The object of the present invention is to provide a vehicle brake system capable of appropriately setting an upper limit value of hydraulic pressure of a by-wire brake during stopping of a vehicle in accordance with conditions. When the vehicle is stopped, a maximum allowable drive voltage calculation unit sets a maximum allowable drive voltage to V2, and sets a brake pressure generated by a motor to P2. When the vehicle is stopped, if a duration time of stopping of the vehicle or a duration time of generation of the brake pressure exceeds a reference value, the maximum allowable drive voltage calculation unit sets the maximum allowable drive voltage to V3, and sets the brake pressure generated by the motor to P3 which is lower than P2.

Abstract: A control system for a machine having a transmission system is provided. The control system includes a wheel speed sensor and a controller. The wheel speed sensor is configured to generate a signal indicative of a wheel speed. The controller is in communication with the wheel speed sensor. The controller is configured to modulate a parameter of a power source based, at least in part, on a comparison of the wheel speed and a localized speed of the machine near the wheel.

Abstract: A method for efficiently decelerating a vehicle having front and rear wheel brakes by isolating the rear wheel brakes and applying pressurized brake fluid only to the front wheel brakes.

Abstract: A device and a method for triggering passenger protection systems, the passenger protection systems being triggered as a function of a rollover process. A signal which characterizes a road grip coefficient (coefficient of friction) is received via an interface. An evaluation circuit is provided which triggers the passenger protection systems as a function of the signal and a stability factor, the evaluation circuit determining the stability factor as a function of at least one kinematic variable.

Abstract: A system and method for controlling an automatic stop-start system of an automotive vehicle is disclosed. The system monitors the status of the parking brake to determine if the parking brake is in a state of transition between an applied state and a released state (in either direction). If the parking brake is in a state of transition, then the automatic re-starting of the engine is inhibited until the parking brake is no longer in a state of transition.

Abstract: A brake control system and method for motor vehicles is provided with an electronic control unit, by which, when the motor vehicle is stationary, a parking brake function can be activated manually or automatically. Its deactivation occurs upon reaching a predefined release condition. In the presence of a release condition the brake pressure, which was built up for the parking brake function, is released in a time offset manner at least in relation to the axles of the vehicle by way of the control unit.

Abstract: A drive controller of an operating machine configured to drive a structure by a hydraulic motor and an electric motor includes: a remote control valve configured to determine the operation amount of the structure; an electric motor torque calculation portion configured to calculate torque of the electric motor; a hydraulic motor torque calculation portion configured to calculate torque of the hydraulic motor; a controller configured to transmit an opening position control signal to the control valve based on the operation amount determined by the remote control valve such that torque necessary to drive the structure is obtained from the torque of the electric motor and the torque of the hydraulic motor; and solenoid-operated reducing valves and each configured to reduce a pilot pressure, to be applied to the control valve, based on the opening position control signal output from the controller.

Abstract: A disk brake device for rail vehicles includes a brake disk for attachment to a chassis and a brake assembly for providing a braking force. The brake assembly has a brake cylinder and a brake caliper that carries a brake pad for cooperating with the brake disk. A sensor is provided on a force transmission path from the brake cylinder to the brake pad. The sensor is configured and arranged to detect a force transfer to the brake disk.

Abstract: A brake control apparatus is provided with a frictional braking unit configured to generate frictional braking force, a regenerative braking unit configured to generate regenerative braking force, a fluid pressure control valve configured to adjust an operating fluid pressure, and a controlling unit configured to execute regenerative control to cover entire required braking force required by a driver by the regenerative braking force and executing switching control to cover the required braking force by the frictional braking force in place of the regenerative braking force by adjusting to increase the operating fluid pressure by the fluid pressure control valve when a predetermined condition is satisfied. By covering the entire required braking force by regenerative braking force and executing the switching control to adjust to increase the operating fluid pressure by the fluid pressure control valve to cover the required braking force when a predetermined condition is satisfied.

Abstract: Systems and methods are provided that may he useful for testing braking systems for use in, for example, an aircraft. A system is disclosed that allows for built in testing. For example, a method if provided comprising sending, from a brake controller, a test command set to at least one of an electromechanical actuator (EMAC) and a brake servo valve (BSV) in response to a landing gear retraction, receiving, at the brake controller, feedback from the at least one of the EMAC and the BSV in response to the test command set, and comparing, at the brake controller, the feedback with a predetermined signature.

Abstract: A torque applying device is provided for applying a driving torque to at least a pair of wheels, and a torque restraining device is provided for restraining the torque created on the wheels to be applied with the torque by the torque applying device. A friction braking device is provided for applying a braking torque to each wheel in response to operation of a brake pedal. An automatic braking control device automatically actuates the friction braking device independently of operation of the brake pedal, to apply the braking torque to each wheel. And, a torque restraining cancellation device is provided for cancelling the torque restraining operation for a time period determined in response to a vehicle speed decreasing state, after a condition for initiating the automatic braking control was fulfilled.

Abstract: A hill start assistance method for a user of a vehicle having a braking system and an electronic braking control, provided with at least one master cylinder pressure sensor, whereby the pressure on each caliper of the vehicle can be controlled. The method includes: estimating the torque transmitted by the clutch, recording information corresponding to the value of the master cylinder pressure resulting from a user's actuation of the brake pedal, and recording the information recorded corresponding to the value of the master cylinder pressure when the user actuates the brake pedal again by pressing harder on the pedal or partially releasing same. When the user releases the brake pedal fully, the braking system maintains the pressure on the calipers for a predetermined period of time, as a function of a pressure set value equal to the value of the last item of information recorded.

Abstract: A device for decelerating or braking a moving mass includes a movably guided coupling member for pressing a brake lining against a braking surface and a brake actuator, filled with hydraulic liquid and connected to the coupling member, for generating a pressure force that can be passed into the brake lining through the coupling member. The brake lining is connected to a pressure transducer that can be fastened on a frame of the mass to be decelerated or braked through a connecting device. The pressure transducer has a hydraulic liquid-filled supporting cylinder and a supporting piston interacting therewith. The supporting cylinder communicates with a brake cylinder through hydraulic lines. This allows an improved adjustment of deceleration or braking. For this purpose, a regulating device adjusts the brake force depending on a predetermined theoretical value.

Abstract: The present invention provides an improved method and apparatus for regulating active damping in a hybrid vehicle powertrain. The method includes: monitoring the damping command sent to the active damping system; determining a mean reference point, which may be a filtered value of the damping torque command; determining if the unfiltered damping torque command value switches from one side to the other of the mean reference point; if a switch is detected, determining if the size of the switch exceeds a predetermined minimum; if it does, then increasing a total number of switches; determining if the total number of switches exceeds a switch threshold; if the total number of switches exceeds the switch threshold, determining if the current damping torque exceeds a damping torque threshold; and decreasing the damping torque if the total number of switches exceeds the switch threshold and the current damping torque exceeds the damping torque threshold.

Abstract: A control method of the torque of a road vehicle having a powertrain system provided with an engine and a driveline which transmits the torque generated by the engine to the road surface; the method contemplates the steps of: determining a target torque; modeling the powertrain system as a single physical component which presents a characteristic mechanical inertia and a characteristic torsional elasticity; determining a current load torque of the vehicle; determining a target torsion of the powertrain system according to the target torque and the current load torque; determining a current torsion of the powertrain system and a current torsion speed of the powertrain system; determining a requested torque on the basis of the energy balance according to the target torsion, the current torsion, the current torsion speed, and the current load torque; and using the requested torque on the basis of the energy balance to control the torque generation of the engine.

Abstract: To provide a brake device for a motor vehicle that can suppress variation in braking force applied to a wheel regardless of variation in friction coefficient between a rotator and a braking means in a fluid pressure brake. A brake device for a motor vehicle is provided with a fluid pressure brake 2 (braking means) that applies brake force according to brake fluid pressure to a brake disk (rotator) 20 fixed to a driving wheel (wheel) 3, and has a first feedback mechanism (pressure-reducing means) 15-1 that applies reaction force inputted from the brake disk 20 to the fluid pressure brake 2 in brake operation in a reducing direction of the brake fluid pressure.

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: 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 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.