Abstract: The trunnion (23) of a vehicle toroidal continuously variable transmission is displaced by a step motor (52) via a control valve (56) and oil pressure servo cylinder (50) in order to vary a speed ratio of the transmission. A controller (80) calculates a target value (z*) of a control variable (z) based on an accelerator pedal depression amount (APS) and output disk rotation speed (&ohgr;co) (S5). Further, a time-variant coefficient (f) showing the relation between the trunnion displacement (y) and variation rate ({dot over (&phgr;)}) of the gyration angle (&phgr;) of the power roller, is calculated (S10). The error between the speed change response of the transmission and a target linear characteristic can be decreased by determining a command value (u) to the step motor (52) under a control gain determined based on a time differential ({dot over (f)}) of the coefficient (f) (S20).

Abstract: A system for monitoring the properties of at least one tire (12) on a vehicle (36) is described, means being provided on the tire to store information representing properties of the tire (12) and sensors (20, 22) being provided for acquiring the information. A method for monitoring properties of at least one tire is also described.

Abstract: A method of detection of the limited slip differential device, wherein it is detected whether a vehicle is mounted with a limited slip differential device on the basis of a relationship between a lateral directional acceleration of a vehicle calculated by using rotational information obtained from tires attached to the vehicle or on the basis of a turning radius of the vehicle, and a specified judged value. It is possible to improve performance and safety of the vehicle since it is possible to accurately judge decrease in internal pressure of a tire.

Abstract: A movement of a vehicle is detected, using tire sensors, by evaluating detected, measured signals in an evaluating unit in such a manner, that the polarity of the measured signals, starting from the measured signals at vehicle standstill, is used as an indicator of the vehicle moving direction.

Abstract: Wheel slip is determined for individual wheels of a vehicle. Minor wheel slippage of wheels is evaluated to determine information concerning wheel performance. This information may provide an early indication of wheel problems. Wheel problems or faults may be displayed or otherwise indicated in response to minor wheel slippage conditions.

Abstract: A method and device that determines a quantity describing a speed of a vehicle. In this method, for at least two wheels, the speeds of these wheels are ascertained, and the quantity describing the speed of the vehicle is ascertained at least as a function of the speed of one selected wheel. The selection of the wheel required for determining the quantity describing the speed of the vehicle takes place at least as a function of an operating state of the vehicle, which is described at least by the speeds of at least two wheels or the quantity ascertained as a function at least of these speeds.

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: A device for estimating a road friction state in which a friction state of a wheel with respect to a road surface can be estimated accurately. A bandpass filter extracts, from a wheel speed signal detected by a wheel speed detecting unit, a portion of the wheel speed signal in a predetermined range which includes a torsion resonance point at which a frequency is greater than a low frequency regions. A vibration level computing unit computes a vibration level of the wheel speed signal. A road friction state estimating unit estimates the friction state of the wheel with respect to the road surface on the basis of a vibration level computed by the vibration level computing unit and an estimated value of a road &mgr; slope computed by a &mgr; slope computing unit, and on the basis of a relationship between the two determined for each road surface state.

Abstract: A system and method for ABS stability control is provided, the method comprising the steps of determining whether a first wheel is in an ABS mode; determining whether the first wheel is in an apply mode; determining whether a second parallel wheel is in the release mode; calculating an adjusted wheel slip if the first wheel is in the ABS mode, the first wheel is in the apply mode, and the second parallel wheel is in the release mode; and determining a control mode for the first wheel using the adjusted wheel slip.

Abstract: A method of coordinating intervention measures into the driving performance of a motor vehicle has the steps of: determining a wheel slip angle &agr;v of a front axle, determining a coefficient of friction &mgr; on the front axle, and determining a wheel slip angle threshold value &agr;v′, where the wheel slip angle &agr;v is compared with the wheel slip angle threshold value &agr;v′ and in the case of an absolute wheel slip angle |&agr;v| which is greater than an absolute wheel slip angle threshold value |&agr;v′|, an intervention measure through the brake system and/or the drive system of the vehicle is implemented. A device for coordinating intervention measures into the driving performance of a vehicle is also described.

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: In an antiskid brake control system, an ECU is constructed to calculate a pseudo vehicle-body speed in accordance with a sensed wheel speed, calculate a target wheel speed in view of a predetermined slip ratio obtained in accordance with a calculated pseudo vehicle-body speed, carry out pressure reducing control by reducing the fluid pressure within a hydraulic unit when the sensed wheel speed is smaller than the calculated target wheel speed, estimate an amount of fluid stored in a reservoir, and correct the target wheel speed to lessen the slip ratio when the estimated fluid amount is greater than a predetermined value.

Abstract: An apparatus and a method for estimating a vehicle speed of a vehicle in which a driving state can be switched between a four-wheel drive (4WD) state and a two-wheel drive (2WD) state. The driving state of the vehicle can be determined based on one or more pieces of information. A controller calculates the vehicle speed based on a wheel speed of at least one non-driven wheel when it is determined that the vehicle is in the 2WD state. When it is determined that the vehicle is not in the 2WD state or when it cannot be determined that the vehicle is in the 2WD state, the controller calculates the vehicle speed based on the lowest one and/or the second lowest one of the wheel speeds of all of the wheels. Further, an apparatus and method for performing predetermined control, such as behavior control or traction control, that perform the control by using the estimated vehicle speed.

Abstract: A system and method of controlling a multi-wheel drive vehicle is provided. The invention is preferably applicable to the steering of such a vehicle and determines the individual velocities for each wheel drive. In this regard, the invention includes two general steps. The first step includes determining the distance of each wheel drive and a vehicle velocity reference point from a turning reference point. The second step includes ratioing each wheel drive's distance from the turning reference point with the vehicle velocity reference point's distance from the turning reference point. The ratios are then applied to a vehicle velocity associated with the vehicle velocity reference point to determine the velocity of each respective wheel drive. Once determined, the velocities are output to each wheel drive.

Abstract: A method and a device for controlling slippage of a vehicle wheel are proposed. A traction controller, which intervenes in a drive torque of a drive unit of the vehicle in response to incipient slippage at at least one driven wheel, is provided. Moreover, it is ascertained whether the vehicle is located in an exit area of a curve. If this is the case, the traction controller is influenced so that improved traction of the vehicle results as compared to cornering designed for stability. Furthermore, at least one quantity determining the intervention is modified in response to cornering or straight-ahead driving.

Abstract: A control system, for use in a vehicle, that influences at least one quantity representing tire slip, and which includes a control unit for controlling at least the drive unit of the vehicle. A traction controller for influencing the engine torque may be implemented in the control unit, and may be used to generate a value for a regulated quantity (or manipulated variable) for the torque of the drive unit based on at least a characteristic map that depends on the slippage and on the slip gradient.

Abstract: A method and device for detecting cornering of a vehicle, or for ascertaining the transverse acceleration (ay) of a vehicle, where a signal indicating cornering of the vehicle, a measure of the curve radius, or the transverse acceleration (ay) of the vehicle is detected, using a reference speed (vS, vSL, vSR) for at least each side of the vehicle; and where a reference speed (vS, vSL, vSR) of one side of the vehicle is determined as a function of the deceleration of at least one wheel on this side of the vehicle.

Abstract: The invention consists in the determination of road conditions during unbraked or partially braked ride of a vehicle through a time derivative of characteristics which are detected on at least one wheel of the vehicle and whose averages are created.

Abstract: In a vehicle attitude control apparatus, a steering actuator is controlled so that a steering angle matches a target steering angle. In an understeer condition; the braking force on the inside wheels is increased and drive power applied to the outside wheels is larger than applied to inside wheels. In an oversteer condition, the braking force on the outside wheels is increased and drive power applied to the inside wheels is larger than applied to outside wheels. The steering actuator is controlled so that a behavior index value corresponding to the change in the vehicle'behavior, that occurs based on the change in the steering angle, matches a target behavior index value that reflects the amount of operation of an operation member. A vehicle yaw moment and an amount of control of the steering actuator vary due to steer conditions, wheel lateral slip angle and brake force control.

Abstract: The present invention is directed to an apparatus for determining a state of braking operation of a vehicle. Wheel speed sensors are provided for detecting wheel speeds of a front wheel and a rear wheel. A wheel speed difference is calculated between the wheel speed of the front wheel and the wheel speed of the rear wheel detected by the wheel speed sensors. A braking operation detection device is provided for detecting an operation of a brake pedal. Based upon the calculated wheel speed difference and the operation of the brake pedal detected by the braking operation detection device, it is determined whether the brake pedal was rapidly depressed. In accordance with this result, and in response to the wheel speeds detected by the wheel speed sensors, the braking force applied to the front wheel can be adjusted in a predetermined relationship with the braking force applied to the rear wheel.

Abstract: The invention describes an apparatus and method for determining at least one wheel slip of a vehicle and at least one of a pitch angle, a road angle, a roll angle for use in at least one vehicle control system. The method and apparatus are characterized in that at least three deflection displacements are determined, and then at least one wheel slip of the vehicle and at least one of the pitch angle, the road angle, the roll angle of the vehicle are determined based on the at least three deflection displacements. The wheel slip(s) of the vehicle and at least one of the pitch angle, the road angle, and the roll angle of the vehicle may be provided or otherwise made available to the at least one vehicle control system.

Abstract: Provided is rotational-state-of-wheel detecting apparatus that can avoid output of an incorrect rotational direction during a halt of a wheel. In ECU 10, a signal input section 10a accurately detects wheel speeds and rotational directions of respective wheels 12, 14, 16, 18, and, based on the results, respective computers 10b, 10c, 10d execute ABS control, TC control, and VSC control. On this occasion, switching of the rotational direction is restricted with a computation result of wheel speed of zero, and it is thus feasible to prevent occurrence of a malfunction or state hunting being repetitive switching of signs, due to an external magnetic field during halts of the wheels 12, 14, 16, 18. This further optimizes the state control of a vehicle.

Abstract: Disclosed a vehicle speed control system using wireless communications, the system including a driving state detecting unit for detecting a driving state and outputting corresponding signals; a transmitter/receiver for outputting low-strength signals; an electronic control unit for receiving the signals of the transmitter/receiver and establishing an ISA mode if necessary, determining if a present driving state corresponds to a first driving state, determining if the driver has performed deceleration operations and performing control into the first driving state if needed; an engine control unit for outputting signals for control of the throttle valve opening; a throttle valve electronic control unit for outputting electrical signals to a throttle valve to control the same; and a display for displaying a present mode and a vehicle state.

Abstract: A device for changing the speeds of the front and rear wheels in a four-wheel-drive vehicle, which is equipped with a continuously variable speed-changing mechanism for the front wheels which changes the input rotational speed and outputs it to the front wheel drive shafts and a continuously variable speed-changing mechanism for the rear wheels which changes the input rotational speed and outputs it to the rear wheel drive shafts. The device for changing the speeds of the front and rear wheels comprises a detector means for detecting the operation conditions of the vehicle and a controller for variably controlling the speeds of said continuously variable speed-changing mechanism for the front wheels and of said continuously variable speed-changing mechanism for the rear wheels based on the operation conditions of the vehicle detected by said detector means.

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: A method and device for detecting cornering of a vehicle, or for ascertaining the transverse acceleration (ay) of a vehicle, where a signal indicating cornering of the vehicle, a measure of the curve radius, or the transverse acceleration (ay) of the vehicle is detected, using a reference speed (vS, vSL, vSR) for at least each side of the vehicle; and where a reference speed (vS, vSL, vSR) of one side of the vehicle is determined as a function of the deceleration of at least one wheel on this side of the vehicle.

Abstract: A moving behavior control device for a vehicle calculates first target braking forces to be applied to the respective wheels for stabilizing the vehicle against a turn instability, second target braking forces to be applied to the respective wheels for stabilizing the vehicle against a roll instability, and target overall braking forces to be applied to the respective wheels by integrating the first and second target braking forces, and applies braking forces to the respective wheels according to the target overall braking forces, wherein the applied braking forces are decreased according to a first rate schedule by which the applied braking forces are decreased at a first rate according to an excess of the applied braking forces relative to the target overall braking forces when the vehicle is running at no probability of rolling beyond a predetermined threshold roll, and according to a second rate schedule by which the braking forces are lowered at a second rate smaller than the first rate according to the

Abstract: A control device for controlling the running behavior of a four wheeled vehicle has a mathematical tire model of each wheel defining a relationship between longitudinal and lateral forces vs.

Abstract: A method for detecting slippery ground in a vehicle with automatic transmission includes detecting the instantaneous running conditions, with the aid of at least one parameter that represents the existence of slippery ground; on the basis of this detection, generating, by counting, a value that represents the change in running conditions as a function of time; comparing the value with reference conditions; as a function of the result of the said comparison, deciding whether or not the instantaneous running conditions correspond to slippery ground.

Abstract: In a process for control of an automatic transmission (3) in a vehicle, it is proposed to set an electronic transmission control (4) for a driving state low friction value when slip is detected on the input gears of the vehicle or an ACS deceleration is detected. In an ACS deceleration a meter is determined, via an ACS evaluation function, from the actual acceleration of the vehicle or a parameter (e.g., gear speed increase) corresponding to the actual acceleration. When slip occurs, a meter is determined, via a slip evaluation function, from the theoretical/actual comparison of the vehicle acceleration or a parameter (e.g., torque reserve) corresponding to said comparison. In both an ACS deceleration or when a slip occurs, a winter operation mode is then activated when the meter count exceeds a limit value.

Abstract: A controller for an electric brake system in a vehicle. The brake system utilizes switched reluctance electric motors to apply braking force to wheels. Such motors have non-ideal torque-speed characteristics, wherein excessive amounts of time and current are required to change torque delivered. The invention reduces the times, and currents, by adjusting the phase angle, and durations, of current pulses delivered to the coils of the motor. The adjustment is based on several parameters, including presently demanded torque, speed of the electric motor, deviation of vehicle system voltage from a norm, and deviation of motor temperature from a norm.

Abstract: A device to monitor sensors in a motor vehicle, with the sensors generating signals that each represent different physical variables is provided. The device has a first arrangement with which identically defined comparison variables for the sensors are determined for at least two sensors on the basis of at least the signals generated by them. Furthermore, the device has a second arrangement with which monitoring is performed for at least one sensor, with the monitoring being performed at least as a function of a sensor reference variable determined for the sensor, the signal generated with the sensor and a respective threshold value. In addition, this device has a second arrangement with which a variable is determined at least as a function of at least two of the identically defined comparison variables and is taken into account in forming the threshold value.

Abstract: The coefficient of friction &mgr;s between the wheels of the vehicle and the road surface is identified as a function of the slip, and the maximum drive torque MAmax which can be transmitted is determined as a function of this slip-dependent coefficient of friction &lgr;. &lgr; is corrected when there is an increased slip requirement &lgr;erf as a result of the speed of the vehicle and/or the tire mixture used.

Abstract: An automotive brake control system with an ABS system employing a hydraulic modulator, wheel-speed sensors, and a skid control unit. A vehicle deceleration &Dgr;Vi is calculated on the basis of a first speed V0 corresponding to the pseudo vehicle speed calculated at a time when the vehicle starts to decelerate and a second speed Vp corresponding to the pseudo vehicle speed calculated at a time when the pseudo vehicle speed is changed from an increasing state to a decreasing state at each cycle of the skid control, from a predetermined expression &Dgr;Vi=(V0−Vp)/T, where T denotes a derivative time.

Abstract: Provided are a method and system for computing a vehicle body slip angle in the vehicle movement control so as to allow the vehicle movement to be controlled with an adequate response and stability for practical purposes even without directly detecting or accurately estimating the frictional coefficient between the road surface and the tire. A tire slip angle is computed from a yaw rate, a vehicle speed, a vehicle body slip angle and a road wheel steering angle; a cornering force is computed from a dynamic model of the tire by taking into account at least the tire slip angle; and a hypothetical vehicle body slip angle is computed from the cornering force, the vehicle speed and the yaw rate; the tire slip angle being computed by feeding back the hypothetical vehicle body slip angle in a recursive manner.

Abstract: A continuously variable transmission of an automobile which varies the drive ratio arbitrarily between an input axis and an output axis is combined with a traction control device for example which performs braking corresponding to vehicle running conditions and irrespective of the accelerator pedal depression. A microprocessor calculates the vehicle speed from the rotation speed of the output axis, calculates the target drive ratio depending on the vehicle speed, and controls the drive ratio of the continuously variable transmission to be equal to the target ratio. When the brake operation device performs braking, fluctuation of the drive ratio based on the rotation variation of the output axis is prevented by the correction of the drive ratio in the upshift direction.

Abstract: A travel state of a vehicle is detected by a travel-state detecting device. A lateral slip angle of a vehicle body is calculated as a first lateral slip angle in a first lateral slip angle calculating device by integrating a differentiated value of lateral slip angle determined based on a non-linear four-wheel vehicle's motion model. A lateral slip angle of the vehicle body is calculated as a second lateral slip angle in a second lateral slip angle calculating device by a calculation in a linear two-wheel vehicle's motion model. One of the first and second lateral slip angles is selected alternatively in a selecting device in accordance with the travel state detected by the travel-state detecting device such that the second lateral slip angle is selected when the travel-state detecting device detects a state in which the vehicle is traveling straightforwardly at a low speed.

Abstract: A device to monitor sensors in a motor vehicle, with the sensors generating signals, each representing different physical is provided. The device includes first arrangement with which identically defined comparison variables for the sensors are determined for at least two sensors on the basis of at least the signals generated by them. Furthermore, the device includes a second arrangement with which a reference variable is determined on the basis of at least two of the identically defined comparison variables and is taken into account in monitoring performed in a third arrangement for at least one sensor. To form the reference variable, a variable describing the difference between the identically defined comparison variable and the other identically defined comparison variables of the minimum of two identically defined comparison variables is determined for each of the minimum of two identically defined comparison variables. The identically defined comparison variable is evaluated using this variable.

Abstract: A wheel module for the control of the braking force on a wheel of a vehicle with an electrically controlled braking system (EBS), in which the need for data transfer to other wheel modules, or to a central module, if present, is reduced considerably. All magnitudes required for an ABS regulation of a wheel such as, for example, vehicle reference speed, are calculated directly in the wheel module according to the invention, so that these magnitudes need not be transmitted from a central module via a data bus.

Abstract: In a vehicle with an active brake control system a control method comprising to the steps of: determining individual wheel speeds of the vehicle wheels responsive to sensor output signals (1016, 1018); determining a vehicle reference velocity responsive to the individual wheel speeds (1002-1012); measuring vehicle yaw rate (1128); determining a delta velocity for each wheel responsive to the individual wheel speed for the wheel and the vehicle reference velocity (326); and when the active brake control system is in the active state for at least one of the wheels, (a) setting a base delta velocity for the one wheel equal to the delta velocity for the one wheel immediately prior to the active brake control obtaining the active state for the one wheel (200); (b) determining a control term responsive to the measured vehicle yaw rate (806), wherein the control term represents a desired delta velocity for the one wheel; (c) setting a first target change in delta velocity responsive to the base delta velocity and th

Abstract: An automotive brake control system with an ABS system employing a hydraulic modulator, wheel-speed sensors, a longitudinal acceleration sensor, and a skid control unit. The skid control unit includes a lateral acceleration dependent offset-value arithmetic-calculation section which arithmetically calculates an offset value based on lateral acceleration exerted on the vehicle. Also provided is a pseudo-vehicle-speed compensation section which decreasingly compensates for a pseudo vehicle speed (an estimated vehicle speed value) by compensating for a signal value of input information data from the longitudinal acceleration sensor by the offset value based on the lateral acceleration exerted on the vehicle owing to the turn, when the vehicle is decelerating.

Abstract: In a method of improving the control behavior of an anti-lock control system, in particular, of the steerability and driving stability during deceleration in a curve, the slip condition of the individual wheels, by determining a slip differential value (SDI) , namely the difference between the momentary wheel slip (&Dgr;v) and the filtered wheel slip (fwsi) and a slip integral or slip summation value (SIi) are detected. The said slip summation value (SIi) is formed by integration of the difference between the momentary wheel slip (&Dgr;vi) and a predetermined permissive slip value (Serl.). Based on these quantities, a wheel condition value is determined which represents the angular slip of the wheel or the transverse dynamics of the wheel. By comparing the values of angular slip of the individual vehicle wheels it is possible to determine the vehicle condition, in particular, an “understeering” or “oversteering” situation.

Abstract: An adhesion control system for a locomotive is provided for achieving and maintaining a maximum adhesion value.

Abstract: In a method of improving the control behavior of an anti-lock control system, criteria for identifying a cornering situation and the direction of curve are obtained from the rotating behavior of the vehicle wheels. For cornering identification, the wheel slip values (&lgr;i) are filtered by way of a first order, low pass and the filtered values are compared. The time constant (T) of the low pass filter is varied as a function of the acceleration (ai) of the respective wheel (i). The time constant (Ti) of the filter starting from a minimum value (Tmin), is increased according to the relation Ti=Tmin+(agrenz−ai)/k1 as soon as the acceleration (ai) of the respective wheel (i) drops below a predetermined limit value (agrenz).

Abstract: A vehicle velocity detecting device is provided for detecting vehicle velocity of a vehicle. In the device, an average of driving wheels' speeds Vw.sub.Dave and an acceleration/deceleration V'w.sub.i of each wheel are calculated. When the average Vw.sub.Dave is less than a designated high wheel speed Vw.sub.Hi of 20 km/h or so and at least one of driving wheels' acceleration/deceleration V'w.sub.DL and V'w.sub.DR is more than a designated low-frequency noise value V'w.sub.LO of 1G or so, the third wheel speed Vw.sub.3rd from the largest wheel speed is set as the vehicle velocity V.sub.SP. When three or more acceleration/deceleration V'w.sub.i are together more than a designated high-frequency noise value V'w.sub.Hi of 5G or so, the wheel speed detected in the past is set as the vehicle velocity V.sub.SP. In either case, the vehicle velocity detecting method by the device is not withdrawn unless the wheel speed Vw.sub.i is less than a designated high wheel speed Vw.sub.LO or unless the average Vw.sub.

Abstract: A signal (S) has a value at every point in time. The values may change in time and may lie within or outside a predetermined basic value range (BVMIN, BVMAX). The signal (S) is processed so that control steps associated with the values of the signal (S) are carried out when certain values of the signal (S) occur outside the basic value range (BVMIN, BVMAX). It may then occur that the carrying out of the control steps may be triggered in an undesirable manner because of implausible values of the signal (S). Such an implausible signal behavior must be recognized rapidly and the undesirable effects of the implausible signal behavior must be decreased or totally prevented at an early moment. For this purpose a value of the signal (S) occurring with relative frequency is determined as a dominant value (DV) as well as a frequency value (FV), which indicates frequency of occurrence of values of the signal (S) situated in the vicinity of the dominant value (DV).

Abstract: An antilock brake control device of this invention includes a electronic control device 30 to operate antilock brake control and the hydraulic unit 20 which operates by a control signal from the electronic control device 30, wherein the maximum target amount of slip is preset, the rate of pressure reduction is determined so as to vary the amount of slip along a quadratic curve which regards the predetermined maximum target amount of slip as a extreme value, and the fluid pressure of the wheel cylinder is reduced at the rate of pressure reduction.

Abstract: A vehicle velocity detecting device is provided for a vehicle. In the device, velocity range in which a difference among respective wheel speeds is caused due to brake noise is defined as a range of speed smaller than a designated velocity V.sub.0. When an average of driving wheels' speeds Vw.sub.Dave is smaller than the designated velocity V.sub.0 and the vehicle is under a great turning condition containing the straight traveling condition, then the smallest wheel speed Vw.sub.MIN is set to a vehicle velocity V.sub.sp in order to exclude the wheel speed being influenced by noise. While, when the vehicle is under a small turning condition where the wheel speed of turning inside wheel is smaller in spite of the same velocity range, the third wheel speed from the largest one is set to the vehicle velocity V.sub.sp to exclude the turning wheel speed. In the velocity range besides both turning conditions, the average of driving wheels' speeds Vw.sub.Dave is set to the vehicle velocity V.sub.

Abstract: An anti-lock braking system includes a friction torque gradient estimating unit for estimating, from a small number of parameters, the gradient of friction torque with respect to a slip speed, and controls a braking force acting on wheels on the basis of the friction torque gradient estimated by the friction torque gradient estimating unit. The friction torque gradient estimating unit may employ several types of estimating methods; e.g.

Abstract: In a four wheel drive vehicle, when rear wheels which are principal drive wheels skid, first a traction control system is operated so as to reduce the drive power to the rear wheels. Thereafter the proportion of drive power apportioned to the front wheels which are auxiliary drive wheels is increased by a torque splitting control system. By doing this, skidding of a wheel due to delay in application of traction control is prevented.