Abstract: A device and method are provided for determining a longitudinal force (Fx) exerted on a wheel of a motor vehicle by a ground surface supporting the wheel, the vehicle including connections means which connect the wheel to a body of the vehicle. An actual force (FAX) is measured at the level of at least one measurement point in the connection means. A force (FDx, Fx) is calculated which results from a transmission via the connection means from the at least one measurement point to the wheel, of a body-associated force (FADX, FAX), which depends at least on the actual force. The longitudinal force (Fx) exerted on the wheel by the ground surface is calculated as a function at least of the force (FDx; Fx) resulting from the transmission of the body-associated force.

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 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: A system is presented for controlling the stability of a vehicle. The system includes a controller using a slip parameter GOPT corresponding to a predetermined value of the coefficient of friction ? or a controller maintaining the functioning of the tire at an optimal value ?OPT of the drift angle corresponding to the maximum value of the draft thrust Ftarget. The controller performs the following operations (where X is either the slip G or the drift angle ?, and Y is either ? or F). Estimations or measurements are determined for at least one pair of values (Xi, Yi). The corresponding values of the slope ?i are determined for the straight line passing through the origin (Xi, Yi). Coefficients Ap are calculated by direct calculation or by a regression from a sufficient number of pairs with (?i, Xi) so as to model a variation curve ?i=f(Xi, Ap). A target value XTarget is calculated by using a predetermined invariant “Invt”.

Abstract: A vehicle movement stabilizing device is provided which in effectively functioning braking, acceleration and turning movement during travel of the vehicle by activating the frictional force adding device, reliably controls the start and end of the operation of the frictional force adding device and prevents repetition of unnecessary operations. The vehicle movement stabilizing device is provided with frictional force adding device for increasing the frictional force of the wheels to the road surface by scattering particles and a controller. The controller is structured to start the operation of the frictional force adding device when it detects the operation start conditions based on signals from wheel speed sensors, a hydraulic pressure sensor and a step-in force sensor during braking, and to stop its operation if signals indicating disappearance of the state are detected, thereby preventing repetition of unnecessary operations.

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: In a method of improving the control behavior of a motor vehicle with anti-lock control, in particular for improving the brake performance on a homogeneous ground, where forces or pressures that act on wheels and tires are determined by sensors and used as control quantities for a motor vehicle control system, both front wheels are adjusted to their brake force maximums, and the front wheel with the lower instantaneously measured brake force or brake pressure is adjusted by a specific brake pressure build-up to its brake force maximum, whereas the other front wheel and the rear wheels are operated by means of a significantly decelerated brake pressure build-up.

Abstract: A method for cyclically controlling the braking of a vehicle includes the following steps: (a) detecting a road surface frictional force of said vehicle, (b) detecting a brake fluid pressure, and (c) controlling the brake fluid pressure in response to detected values including the brake fluid pressure and the road surface frictional force, the controlling including decreasing the brake fluid pressure in response to the road surface frictional force declining during an increase of the brake fluid pressure and increasing the brake fluid pressure in response to the road surface frictional force declining during fall-off of the brake fluid pressure.

Abstract: A braking force control device, wherein wheel speed is detected and a slope of a braking force with respect to slip speed of the wheel is estimated on the basis of the detected wheel speed, a braking operation by which a brake pedal is depressed is detected and, on the basis of the detected braking operation conditions and estimated slope of the braking force, braking of the braking device to brake the wheels by a braking force generated in response to the braking operation by which the brake pedal is depressed is assisted.

Abstract: A system for controlling the stability of a vehicle having tires, the system including a controller using at least the parameter slip GOpt corresponding to a predetermined value of the coefficient of friction &mgr;, or the system including a controller maintaining the functioning of the tire at an optimum value &dgr;Opt of the drift angle corresponding to the maximum value of the drift thrust Ftarget, the controller including means for performing the following operations (where X is either the slip G or the drift angle &dgr;, and Y is either &mgr; or F):

Abstract: The invention provides a brake control device for a vehicle, a brake control method and a recording medium having a program causing a computer to perform the brake control method. A tire friction characteristic with respect to a vehicle velocity or a wheel velocity is memorized in advance. When a brake is put on to the vehicle, a current slip ratio or a current slip velocity is found and an optimum slip ratio or an optimum slip velocity is calculated using the tire friction characteristic. Then, a difference between the optimum slip ratio and the found current slip ratio or a difference between the optimum slip velocity and the found current slip velocity is compared with a predetermined value. According to a result of the comparison, a braking force applied to the vehicle is controlled.

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: A method for variably setting the braking force in a hydraulic brake system of a motor vehicle with a brake pressure is produced which is applied to a wheel-braking device. In order to compensate a diminishing braking effect in hydraulic brake systems in wide ranges, the real actual friction factor between the brake disc and brake pad of at least one wheel brake is determined and compared with a prescribable desired friction factor, in the event of an impermissible undershooting of the actual friction factor by comparison with the desired friction factor, the brake pressure or a variable correlated with the brake pressure being increased to a value multiplied by a correction factor if the actual friction factor is within a defined friction factor stabilization range which comprises a plurality of friction factors below the desired friction factor.

Abstract: A method for improving the traction between a road surface and a motor vehicle having a pair of front wheels and a pair of rear wheels which engage the road, each front wheel mounted on a front axle, each rear wheel mounted on a rear axle, one of the axles being a driven axle, and a two-part undercarriage roll stabilizer system including a front and a rear undercarriage stabilizer, each the undercarriage stabilizer comprising an actuating drive operatively coupled to a the pair of wheels, and for reducing the stopping distance along the road in which the motor vehicle can be stopped. The method includes: determining a coefficient of friction between at least two wheels and the road surface; comparing the coefficients of friction; and tensioning the actuating drives diagonally, the wheel contact forces between diagonally opposite wheels and the road surface thereby being one of increased and decreased in response to the determined coefficient of friction between a wheel and the road surface.

Abstract: In an anti-lock brake system mounted on a vehicle wherein when the vehicle is braked in an emergency during running, an increase in the road surface friction force or road surface friction coefficient owing to an increase in the brake pressure is detected by a road surface friction force detecting device or road surface friction coefficient detecting device. The optimum control start point associated with an increase in the signal value of the road surface friction force F or road surface friction coefficient &mgr; provided by the road surface friction force detecting device or road surface friction coefficient detecting device is decided by using a decrease in the wheel speed, i.e., by using the wheel speed &ohgr; or d&ohgr;/dt. Thereafter, from the point where the specified value of control based on F or &mgr;, or dF/dt or d&mgr;/dt, the brake pressure is moved from the pressure increasing mode to the pressure retaining or decreasing mode.

Abstract: The invention provides a brake control device for a vehicle, a brake control method and a recording medium having a program causing a computer to perform the brake control method. A tire friction characteristic with respect to a vehicle velocity or a wheel velocity is memorized in advance. When a brake is put on to the vehicle, a current slip ratio or a current slip velocity is found and an optimum slip ratio or an optimum slip velocity is calculated using the tire friction characteristic. Then, a difference between the optimum slip ratio and the found current slip ratio or a difference between the optimum slip velocity and the found current slip velocity is compared with a predetermined value. According to a result of the comparison, a braking force applied to the vehicle is controlled.

Abstract: A vehicular braking control apparatus and method controls frictional braking performed by a frictional braking device, controls regenerative braking performed by a regenerative braking device, and controls shifting between a cooperative braking mode, realized by the frictional braking and the regenerative braking, and a single braking mode, realized by only the frictional braking. A correction coefficient for one of a frictional braking control amount and a regenerative braking control amount is calculated on the basis of an actual degree of vehicle deceleration and a reference degree of vehicle deceleration based on an amount of braking operation performed by a driver during braking in the single braking mode. The control amount is corrected based on the correction coefficient.

Abstract: A slip angle calculating unit calculates a slip angle of a vehicle body corresponding to a steering wheel angle and a vehicle speed, based on a vehicle wheel angle and the vehicle speed, by an observer of a preset vehicle motion model under a motion equation of a vehicle. A front wheel slip angle calculating unit calculates a front wheel slip angle based on the steering wheel angle, a vehicle speed, a yaw rate, and the calculated vehicle body slip angle. A self-aligning torque calculating unit calculates the self-aligning torque based on the hydraulic chamber pressure of the left side and the hydraulic chamber pressure of the right side in a power cylinder. The vehicle speed, an estimated front wheel slip angle, and the self-aligning torque are inputted to a road friction coefficient setting unit, and the road friction coefficient setting unit sets a road friction coefficient by referring to a map based on the input to output the set value.

Abstract: A control section of a road friction coefficient estimating apparatus inputs a vehicle speed, a steering wheel angle and a yaw rate from a vehicle speed sensor, a steering wheel angle sensor and a yaw rate sensor, respectively. The control section comprises a reference yaw rate calculating section, a yaw rate deviation calculating section, a yaw rate deviation dispersion calculating section and a road friction coefficient establishing section. The reference yaw rate calculating section calculates a reference yaw rate based on vehicle speed and steering angle in accordance with a vehicle motion model. The yaw rate deviation calculating section calculates a yaw rate deviation based on the reference yaw rate and the actual yaw rate. The yaw rate deviation dispersion calculating section calculates a dispersion of the yaw rate deviation for a specified sampling number.

Abstract: The present invention provides a method of estimating a coefficient of adhesion between a road surface and a plurality of tires disposed on a vehicle. An estimated coefficient of adhesion for each of the plurality of tires is provided. First values of longitudinal and lateral forces on the tires are determined from a first set of vehicle dynamic parameters requiring no explicit knowledge of the coefficient of adhesion; and second values of the same forces are determined from a second set of vehicle parameters in an analytic tire model including the estimated value of the coefficient of adhesion. Differences between the first and the second values of the forces on the tires are determined in the longitudinal and lateral directions. Longitudinal and lateral adaptation speeds are determined for each of the plurality of tires; and a coefficient of adhesion adjustment for each of the plurality of tires is estimated from the differences and the adaptation speeds.

Abstract: The invention relates to an arrangement for a vehicle which incorporates powered wheels (1a-b) arranged on a first axle, unpowered wheels (1c-d) arranged on at least one second axle, an engine unit for the vehicle's propulsion and a brake configuration which includes brake devices which are wheels. The arrangement is designed to estimate the level of friction between the vehicle's wheels and running surfaces.

Abstract: An improved anti-lock brake control method adaptively determines exit criteria for terminating anti-lock brake control based on rate of brake pedal release and estimates of the brake torque and road surface coefficient of friction. The brake torque and road surface coefficient of friction are estimated based on a periodically updated characterization of the relationship between brake pedal position and vehicle deceleration.

Abstract: A vehicular antilock brake control system does not require a lengthy extension piping from its actuator. The system provides for an accurate controlling method for maximizing a calculated road surface friction coefficient. Each wheel has a control unit consisting of a stress sensor, a controller and an actuator installed at the respective wheel. A stress value is detected, representative of road surface friction value or road surface friction coefficient value, for the corresponding wheel independently of the other wheels. In response to the output signal of the sensor, the controller regulates the actuator which controls brake fluid pressure applied to the respective wheel.

Abstract: An improved anti-lock brake control method in which the brake pressure reduction initiated upon detection of insipient wheel lock is adaptively determined based on a periodically updated characterization of the relationship between brake pedal position and vehicle deceleration. The brake torque and vehicle weight are estimated based on the characterization data, corrected for variation in brake heating, and used to compute the surface coefficient of friction, which in turn, is used to schedule the initial anti-lock brake pressure reduction for optimal braking system performance.

Abstract: An apparatus and method that determines a maximum road friction coefficient for each wheel regardless of whether the tire is in a predetermined drive slip state, and whether the wheel is a driving wheel. The braking force of each wheel is calculated, and the longitudinal force of the tire of each wheel is calculated. Then, the driving force of the vehicle is calculated, and the lateral force of the tire of each wheel is calculated. Next, the reaction force of the road to each wheel is calculated, and the vertical load of each wheel is calculated. Finally, the ratio of variation in reaction force of the road to variation in composite slip ratio is calculated for each wheel. The sum of the ratio of the reaction force of the road to the vertical load, and the product of a predetermined coefficient and the ratio of variation in reaction force of the road to variation in composite slip ratios is calculated for each wheel as the maximum road friction coefficient.

Abstract: A wheel velocity signal for each wheel detected by a wheel velocity sensor is input to a bandpass filter. Signals from frequency bands unrelated to the unsprung resonance are then removed from the wheel velocity signal and only signals from frequency bands related to the unsprung resonance are output. A road surface &mgr; gradient estimation device uses an online identification method to identify an damping ratio of a second order resonance model similar to a suspension—tire resonance model from the signal output from the bandpass filter. The road surface &mgr; gradient is then estimated from the identified damping ratio. The damping ratio of the second order resonance model corresponds to the road surface &mgr; gradient in the following manner: when the damping ratio is identified as being small, the road surface &mgr; gradient is estimated as being large; and when the road surface &mgr; gradient is identified as being large, the damping ratio is estimated as being small.

Abstract: In an adaptive speed control system for a vehicle, a method and system for automatically adjusting a selected following interval for the vehicle based on driving conditions is provided. The method includes determining a driving surface coefficient of friction based on a driven wheel speed of the vehicle, and adjusting the selected following interval for the vehicle based on the driving surface coefficient of friction. The system includes a receiver capable of receiving a signal indicative of a driven wheel speed of the vehicle, and a controller capable of determining a driving surface coefficient of friction based on the driven wheel speed, and capable of adjusting the selected following interval for the vehicle based on the driving surface coefficient of friction.

Abstract: The braking effect in a vehicle is set in the sense of preventing a tendency to lock-up with at least two wheels which are arranged on at least one axle on the right and left and whose motion characteristics are detected. The braking effect on the two wheels is set jointly, with at least two operating modes (select low, select high) being provided; they can be selected depending on the coefficients of friction prevailing on the wheels and/or depending on the vehicle speed. An operating mode is selected according to the value of the prevailing coefficients of friction when there are coefficient of friction differences of a preselectable lower value. As an alternative or in addition, an operating mode is selected according to the detected vehicle speed when there are coefficient of friction differences of a preselectable greater value.

Abstract: A braking force control device is provided in which wheel speeds of respective wheels of a vehicle are detected. On the basis of detected wheel speeds, a road surface &mgr; slope, which is a slope of a coefficient of friction &mgr; between a wheel and a road surface, is estimated for each wheel. On the basis of the road surface &mgr; slope estimated for each wheel, a braking force of each wheel is controlled such that the braking force of each wheel is adjusted.

Abstract: An ABS apparatus according to the present invention has an arbitrary number of first sensors (15, 16) capable of obtaining road frictional force information according to road frictional force F acting between a wheel of a car and a road on which the car is moving and braking torque information according to braking torque T acting between the wheel of the car and a braking equipment, a differential parameter calculating means (21) for calculating a differential parameter M according to the road frictional force information and the braking torque information from these first sensors (15, 16), and a solenoid valve controlling means (23) for starting and then stopping a pressure reducing operation when the differential parameter M calculated by the differential parameter calculating means (21) reaches a first threshold provided according to a peak value of the differential parameter M or a second threshold having an absolute value slightly smaller than that of the first threshold while the barking equipment is in

Abstract: A vehicle brake control device includes a brake member, a wheel brake cylinder mounted on a wheel, and a master cylinder. The master cylinder generates a master cylinder hydraulic pressure in response to an operating force applied to the brake member. The brake control device also includes an automatic pressure increasing control device, a braking force control device, a coefficient of friction detecting device that detects a coefficient of friction of the road, and an automatic pressure increasing restraining device. The automatic pressure increasing control device controls automatic pressure increasing operation of the master cylinder based on the operating force applied to the brake member. The braking force control device controls the increased master cylinder hydraulic pressure supplied to the wheel brake cylinder.

Abstract: A braking force control device, wherein wheel speed is detected and a slope of a braking force with respect to slip speed of the wheel is estimated on the basis of the detected wheel speed, a braking operation by which a brake pedal is depressed is detected and, on the basis of the detected braking operation conditions and estimated slope of the braking force, braking of the braking device to brake the wheels by a braking force generated in response to the braking operation by which the brake pedal is depressed is assisted.

Abstract: A vehicular antilock brake control system does not require a lengthy extension piping from its actuator. The system provides for an accurate controlling method for maximizing a calculated road surface friction coefficient. Each wheel has a control unit consisting of a stress sensor, a controller and an actuator installed at the respective wheel. A stress value is detected, representative of road surface friction value or road surface friction coefficient value, for the corresponding wheel independently of the other wheels. In response to the output signal of the sensor, the controller regulates the actuator which controls brake fluid pressure applied to the respective wheel.

Abstract: In an anti-lock brake system mounted on a vehicle wherein when the vehicle is braked in an emergency during running, an increase in the road surface friction force or road surface friction coefficient owing to an increase in the brake pressure is detected by a road surface friction force detecting device or road surface friction coefficient detecting device. The optimum control start point associated with an increase in the signal value of the road surface friction force F or road surface friction coefficient &mgr; provided by the road surface friction force detecting device or road surface friction coefficient detecting device is decided by using a decrease in the wheel speed, i.e., by using the wheel speed &ohgr; or d&ohgr;/dt. Thereafter, from the point where the specified value of control based on F or &mgr;, or dF/dt or d&mgr;/dt, the brake pressure is moved from the pressure increasing mode to the pressure retaining or decreasing mode.

Abstract: A vehicle running condition judgment device for accurately detecting a change in a road surface condition and a vehicle's limit running condition. With substitution of respective tire characteristics and a detected state quantity into a vehicle motion model, vehicle slip angles are estimated for respective assumed road surface conditions. Based on the current state quantity and the last estimated vehicle slip angle, currently estimated vehicle slip angles for the respective assumed road surface conditions are compensated. A differential operation section calculates an estimation value of a vehicle slip angular velocity for each of the assumed road surface conditions based on the compensated vehicle slip angles for the respective assumed road surface conditions. Meanwhile, an operation section calculates a detection value of a vehicle slip angular velocity based on the detected state quantity.

Abstract: The present invention is directed to a system for detecting a difference in level on a road, wherein an acceleration sensor is provided for detecting an acceleration of a vehicle, and a wheel speed sensor is provided for detecting a wheel speed of at least one wheel of the vehicle. A wheel acceleration is calculated continuously on the basis of the wheel speed detected by the wheel speed sensor. It is determined if a variation of the signal output from the acceleration sensor is greater than a predetermined range. And, it is determined if the calculated wheel acceleration varied in the same direction as that of the variation of the signal output from the acceleration sensor, and then varied in the reverse direction to exceed a predetermined reference value. On the basis of the result of each determination, it is determined if the wheel ran over the difference in level on the road. If the affirmative result is obtained in each determination, the difference in level on the road can be detected.

Abstract: In an adaptive speed control system for a vehicle, a method and system for automatically adjusting a selected following interval for the vehicle based on driving conditions is provided. The method includes determining a driving surface coefficient of friction based on a driven wheel speed of the vehicle, and adjusting the selected following interval for the vehicle based on the driving surface coefficient of friction. The system includes a receiver capable of receiving a signal indicative of a driven wheel speed of the vehicle, and a controller capable of determining a driving surface coefficient of friction based on the driven wheel speed, and capable of adjusting the selected following interval for the vehicle based on the driving surface coefficient of friction.

Abstract: A system is provided wherein road surface friction is sensed by measuring strain on a structure of a vehicle in a vicinity of a wheel of the vehicle. A road surface friction coefficient is determined by measuring strain on a structure of the vehicle in the vicinity of the wheel to produce signal outputs proportional to road surface frictional force and vertical load, and calculating the road surface friction coefficient from the outputs.

Abstract: In an anti-lock brake system mounted on a vehicle wherein when the vehicle is braked in an emergency during running, an increase in the road surface friction force or road surface friction coefficient owing to an increase in the brake pressure is detected by a road surface friction force detecting device or road surface friction coefficient detecting device. The optimum control start point associated with an increase in the signal value of the road surface friction force F or road surface friction coefficient &mgr; provided by the road surface friction force detecting device or road surface friction coefficient detecting device is decided by using a decrease in the wheel speed, i.e., by using the wheel speed &ohgr; or d&ohgr;/dt. Thereafter, from the point where the specified value of control based on F or &mgr;, or dF/dt or d&mgr;/dt, the brake pressure is moved from the pressure increasing mode to the pressure retaining or decreasing mode.

Abstract: According to one aspect of the invention, a brake controller is provided for controlling an amount of braking force applied to a plurality of wheels of a vehicle running on a surface. Each of the plurality of wheels has a sensor for providing an output signal indicative of a corresponding speed of the wheel. The controller includes a state estimator which estimates an amount of friction between each of the plurality of wheels and the surface based on the output signals of the sensors, the estimated amount of friction for each wheel being based on the estimated amount of friction for the other wheels. The controller further includes a control output which adjusts the amount of braking force applied to the plurality of wheels based on the estimated amount of friction.

Abstract: In an adaptive speed control system for a vehicle, a method and system for automatically adjusting a selected following interval for the vehicle based on driving conditions is provided. The method includes determining a driving surface coefficient of friction based on a driven wheel speed of the vehicle, and adjusting the selected following interval for the vehicle based on the driving surface coefficient of friction. The system includes a receiver capable of receiving a signal indicative of a driven wheel speed of the vehicle, and a controller capable of determining a driving surface coefficient of friction based on the driven wheel speed, and capable of adjusting the selected following interval for the vehicle based on the driving surface coefficient of friction.

Abstract: The present invention is directed to an apparatus for estimating the peak of a coefficient of friction in a coefficient of friction—slip rate characteristic, wherein a wheel acceleration of each wheel of a vehicle is detected, and a vehicle acceleration of the vehicle is detected. A peak estimation device is provided for estimating the peak of the coefficient of friction, and adapted to determine that the coefficient of friction is the peak when the wheel acceleration is lower than the vehicle acceleration, by more than a predetermined difference. An anti-skid control system for an automotive vehicle may be formed to include the coefficient of friction peak estimation apparatus, and a reference speed setting device for setting a reference speed for initiating a pressure decrease mode on the basis of a wheel speed and a vehicle speed detected when the peak was detected.

Abstract: An improved active brake control method which compensates for the effects of a banked road surface under both steady state and transient operating conditions of the vehicle. The control includes an observer for estimating the lateral velocity of the vehicle as a means of determining vehicle slip angle, and a time derivative of the estimated lateral velocity is used along with measured values of lateral acceleration, vehicle speed and yaw rate to compute the lateral acceleration component due to the banked road surface, referred to as the bank acceleration. The bank acceleration, in turn, is then used to correct the values of measured steering angle and the measured lateral acceleration used (1) to develop the desired yaw rate, slip angle and lateral acceleration, and (2) to estimate the surface coefficient of adhesion and slip angle. Partial compensation can be achieved by applying suitable gain factors to the computed bank acceleration, if desired.

Abstract: A method is provided for generating a vehicle lateral acceleration signal for use in an active tilt control system in a vehicle having a sprung mass center of gravity. A single lateral accelerometer is mounted at the sprung mass center of gravity of the vehicle to generate a first lateral acceleration signal (acg). A second lateral acceleration signal (aLapprox) is generated representative of a vehicle lateral acceleration at a point spaced from the sprung mass center of gravity based upon the first lateral acceleration signal for use in the active tilt control system.

Abstract: An anti-skid control system includes a hydraulic pressure generator for generating hydraulic brake pressure, hydraulic pressure control valves which control the brake hydraulic pressure of the wheel cylinders, wheel speed sensors for detecting the rotational speed of the wheels, and a controller for controlling the hydraulic pressure control valves to decompress or pulse-boost the brake hydraulic pressure in the wheel cylinders based on the output signal of the wheel speed sensors. A brake pedal depression amount detecting device detects the amount of depression of the brake pedal. The controller includes a road surface change judging device for judging that the road surface has shifted from a surface having a low coefficient of friction to a surface having a high coefficient of friction when a continuous run pulse number or a continuous run time of the pulse boost control exceeds a preset value.

Abstract: A brake system control method, comprising the steps of: determining a maximum acceleration of a vehicle on a high coefficient of adhesion road surface; measuring an acceleration of the vehicle; determining a ratio between the measured acceleration of the vehicle and the maximum acceleration of the vehicle on the high coefficient of adhesion road surface; responsive to the ratio, determining a signal indicative of present coefficient of adhesion; determining a brake actuator command responsive to the signal; and providing the brake actuator command to a brake actuator, wherein an accurate estimation of coefficient of friction between the vehicle wheels and the road surface is used in the brake system control.

Abstract: An antiskid brake controller utilizes measured wheel speed in order to provide brake control for a vehicle such as an aircraft. The controller estimates the speed of the vehicle via approximation based on the measured wheel speed and a model of the mu-slip ratio curve representing the wheel to running surface friction characteristics. The controller then predicts the slip ratio based on the measured wheel speed and estimated vehicle speed. The difference between the predicted slip ratio and a predefined desired slip ratio is used to drive a modified integral controller segment to achieve maximum obtainable friction. In another embodiment, the controller measures and integrates the applied braking torque in order to estimate the vehicle speed. The estimated vehicle speed is again combined with the measured wheel speed to determine an estimated slip ratio. The controller compares the estimated slip ratio with a predefined desired slip ratio which again drives a modified integral controller.

Abstract: A braking force control system and method of a vehicle comprises a steering angle detecting section for detecting a steering angle, a vehicle speed detecting section for detecting a vehicle speed, an actual yaw rate detecting section for detecting an actual yaw rate, a target yaw rate calculating section for calculating a target yaw rate, a target yaw rate restricting section for restricting the target yaw rate to an upper limit value, a yaw rate deviation calculating section for calculating a yaw rate deviation of the actual yaw rate and the target yaw rate, a target braking force calculating section for calculating a target braking force, a braking wheel determining section for determining a braking wheel, an output judging section for judging whether the yaw rate deviation is in a control zone or in a noncontrol zone.

Abstract: An antilock brake control system for a vehicle includes a control start determining device for determining that an antilock brake control should be started, in response to a slip rate calculated based on a wheel speed and a presumed vehicle speed exceeding a start determination threshold value determined as a function of the presumed vehicle speed. The control start determining device changes the function of the presumed vehicle speed for calculating the start determination threshold value, based on the state of the antilock brake control for a wheel other than a wheel which is subjected to the determination by the control start determining device, and the results of the determinations by the road surface friction coefficient determining device and the bad-road determining device. Thus, appropriate antilock brake control for the situation of a road surface is conducted.

Abstract: Electrical, continuously acting wheel brake actuators are individually controlled. The following calculation and control procedures are carried out in a control unit: the wheel slip and the wheel acceleration are calculated for each wheel; if the wheel slip or the wheel acceleration exceed a predefined first threshold value, then the respective actual value of the brake pressure is stored; the quotient of the stored actual value and a pressure value which is characteristic of the vehicle is formed for the respective wheel, and the coefficient of friction .mu. is thus estimated; and an ABS brake-pressure closed-loop control operation is carried out at the individual wheels using the value.