Abstract: A turning motion control system for a vehicle includes an actuator, and an actuator control device for controlling the actuator so that an actual turning motion state of the vehicle becomes close to a target turning motion state. The actuator control device is designed so that its control-permitted state and its control-stopped state can be switched from one to another through a switching device operated by a driver. When an air-pressure decreased state detecting device has detected an air-pressure decreased state, the actuator control device carries out the control of the operation of the actuator, irrespective of a switching mode of the switching device. Thus, even if an air-pressure decrease or an abnormality is generated in any of wheels in a state in which the turning motion control by the actuator has been stopped, the stability of the vehicle can be ensured.

Abstract: A turning motion control system for a vehicle includes an actuator, and an actuator control device for controlling the actuator so that an actual turning motion state of the vehicle becomes close to a target turning motion state. The actuator control device is designed so that its control-permitted state and its control-stopped state can be switched from one to another through a switching device operated by a driver. When an air-pressure decreased state detecting device has detected an air-pressure decreased state, the actuator control device carries out the control of the operation of the actuator, irrespective of a switching mode of the switching device. Thus, even if an air-pressure decrease or an abnormality is generated in any of wheels in a state in which the turning motion control by the actuator has been stopped, the stability of the vehicle can be ensured.

Abstract: A turning motion control system for a vehicle includes an actuator, and an actuator control device for controlling the actuator so that an actual turning motion state of the vehicle becomes close to a target turning motion state. The actuator control device is designed so that its control-permitted state and its control-stopped state can be switched from one to another through a switching device operated by a driver. When an air-pressure decreased state detecting device has detected an air-pressure decreased state, the actuator control device carries out the control of the operation of the actuator, irrespective of a switching mode of the switching device. Thus, even if an air-pressure decrease or an abnormality is generated in any of wheels in a state in which the turning motion control by the actuator has been stopped, the stability of the vehicle can be ensured.

Abstract: In a vehicle behavior control system, a failure of a wheel speed sensor is detected by a wheel speed sensor failure detecting device based on the mutual comparison of wheel speeds detected by wheel speed sensors, respectively. When the failure of the wheel speed sensor is detected, a preselected fail-safe operation is carried out by a fail-safe device. A fail-safe operation prohibiting signal is output only for a predetermined time from the establishment of a state in which the operation of a parking brake is detected by a parking brake operation detecting device and a during-traveling signal is output from a during-traveling signal generated device. When the fail-safe operation prohibiting signal is output, the fail-safe operation by the fail-safe device is prohibited by a fail-safe operation prohibiting device.

Abstract: In an anti-lock brake control system, an actuator is controlled based on at least a slip rate determined in a slip rate calculating device and an output from a low-pass filter for filtering a wheel acceleration determined in a wheel acceleration calculating device, thereby switching-over the braking-pressure reducing, maintaining and increasing modes from one to another. The braking pressure-reduction control provided by an operation control device is terminated in response to the wheel acceleration determined in the wheel acceleration calculating device becoming equal to or larger than a preset value. Thus, it is possible to prevent an excessive pressure reduction during an anti-lock brake control on a road surface having a high coefficient of friction.

Abstract: In an anti-lock brake control system for a vehicle, first presumed vehicle speeds are calculated in first vehicle speed calculating devices for every wheel based on wheel speeds detected by wheel speed detecting sections. A second presumed vehicle speed is calculated in a second vehicle speed calculating device based on the value of a lower one of the first presumed vehicle speeds calculated in the first vehicle speed calculating devices corresponding to the left and right rear wheels. A higher one of the first presumed vehicle speeds calculated in each of the first vehicle speed calculating devices and the second presumed vehicle speed calculated in the second vehicle speed calculating device is selected as a presumed vehicle speed corresponding to the wheel in a high-select device. The operations of actuators are controlled based on results of calculation of slip rates of wheels based on presumed vehicle speeds and wheel speeds for every wheel.

Abstract: A method of controlling the driving state of a vehicle in which an antilock brake control for eliminating a locking tendency of a wheel during braking can be carried out, and a four-wheel drive state and a two-wheel drive state can be switched from one to another. A monitored estimated vehicle speed is calculated on the basis of highest one of wheel speeds of the vehicle wheels and a value is detected by a longitudinal acceleration/deceleration sensor for detecting a longitudinal acceleration or deceleration of a vehicle speed, and a judgement speed is determined at a value lower than the monitored estimated vehicle speed. The vehicle speed is also independently determined based upon the speed of each of the vehicle wheels. The four-wheel drive state is switched to the two-wheel drive state in response to highest one of vehicle speeds independently calculated on the basis of the wheel speeds becoming equal to or less than the judgement speed in the four-wheel drive state.

Abstract: A process for calculating estimated vehicle speeds on the basis of wheel speeds of the vehicle wheels and a value resulting from addition of an offset value corresponding to an output error including a dispersion component and a slope component of an output from a longitudinal acceleration/deceleration sensor to a detection value detected by the longitudinal acceleration/deceleration sensor. In a condition in which it is determined that a vehicle is traveling at a substantially constant speed for a relatively long period of time, a first correction amount is calculated from an average value of variations in wheel speeds and an average value of outputs from the longitudinal acceleration/deceleration sensor during the long period of time.

Abstract: An antilock brake control method for a four-wheel drive vehicle including calculating an estimated vehicle speed on the basis of a wheel speed of a wheel and a value obtained by adding an offset value to an output from a longitudinal acceleration/deceleration sensor for detecting a longitudinal acceleration or deceleration of the vehicle. When it is detected that all of the four wheels are in their spinning state, the addition of the offset value to the output from the longitudinal acceleration/deceleration sensor is stopped, and the estimated vehicle speed is calculated on the basis of the wheel speed and the output from the longitudinal acceleration/deceleration sensor.

Abstract: A traction control method for a vehicle, comprising the steps of: judging an excessive slipping state of a plurality of driving wheels by taking into account, as at least one judgment requirement, whether or not a driving-wheel speed exceeds a braking-force controlling target wheel speed determined by taking into account a predetermined slip rate of a vehicle speed, and controlling a braking force for the driving wheels in accordance with the result of the judgment, wherein the intensity of a slipping tendency for every one of the driving wheels is determined on the basis of a judgment value which is set larger than the vehicle speed and smaller than the braking-force controlling target wheel speed, and the smaller the number of the driving wheels determined to have a large slipping tendency, the more the braking-force controlling target wheel speed is increased. This prevents the occurrence of an excessive control of braking force, when the slipping tendency of only a part of the driving wheels is large.

Abstract: A data communication system transmits a first data signal from a first control unit to a second control unit. The data communication system includes a clock signal line for transmitting a clock signal between the first and second control units. In performing data communication, the first control unit first transmits a first trigger signal via a first trigger signal line to the second control unit for informing the second control unit of the start of transmission of the first data signal. The first control unit then transmits the first data signal via a first data signal line to the second control unit. A second trigger signal line transmits a second trigger signal from the second control unit to the first control unit for informing the first control unit of the start of transmission of the second data signal. The second control unit then transmits the second data signal via a second data signal line to the first control unit in synchronization with the clock signal.

Abstract: A method for traction control of a vehicle, includes the steps of detecting a slipping tendency of a driving wheel in a driving state and controlling a suppression of driving torque of the driving wheel in accordance with the slipping tendency of the driving wheel, such that, when the vehicle is being reduced in speed, the control of the suppression of driving torque has a reduced control sensitivity. Further, the reduced control sensitivity may actually inhibit the suppression of driving torque.

Abstract: A pressure source for a pressure device includes a pump for pumping fluid from fluid tank, an accumulator connected to the pump and a pressure device, a device for detecting the pressure in the accumulator, and a controller for controlling the operation of the pump in an ON-OFF manner on the basis of a result of detection by the pressure detecting device. In this pressure source, the controller includes first and second drive signal generating circuits each capable of independently generating a drive signal for determining the on-off operation of the pump, and a judging circuit which has a calculating function therein and to which at least the pressure detecting device is connected. The judging circuit is connected to the first drive signal generating circuit, and the pressure detecting device is connected to the second drive signal generating circuit.

Abstract: A first vehicle body speed is calculated based on a wheel rotational speed detected in a speed sensor for an object wheel. The largest value of speeds based on the wheel rotational speeds detected in speed sensors for four wheels is corrected by a correction value based on an inner and outer wheel speed difference during the turning of a vehicle so as to calculate a second vehicle body speed for every object wheel. A higher one of the first and second vehicle body speeds is selected as an estimated vehicle body speed for use in the anti-lock control for the object wheel. This enables a substantially accurate estimation of an estimated vehicle body speed during the turning of the vehicle.

Abstract: An anti-lock control system includes wheel speed detecting device, wheel acceleration/deceleration detecting device, vehicle pseudo-speed calculating device for calculating a vehicle pseudo-speed on the basis of a wheel speed detected by the wheel speed detecting device, storing device for storing a wheel speed or vehicle pseudo-speed at a sampling time at which the wheel acceleration/deceleration has become equal to or less than preset acceleration set at a value near "0" (zero), including "0" (zero), after passing a peak in the course of increasing of the wheel speed, speed difference calculating device for calculating a speed difference between wheel speeds or vehicle pseudo-speeds stored currently and last time in the storing device, lapsed-time counting device for counting the time lapsed from the last sampling time to the current sampling time, and division device for dividing the speed difference by the lapsed time to provide a value corresponding to a friction coefficient of a road surface.

Abstract: A traction control method for a vehicle according to the present invention for generating braking forces in the brake devices for driving wheels when excessive slipping has occurred in the drive wheels involves an independent control mode for independently controlling respective braking forces of the plurality of drive-wheel brake devices and a collective control mode for collectively controlling the braking forces. These two control modes are interchangeable with each other. This enables traction control which can insure both reliable driving force and high stability.

Abstract: A traction control method for a vehicle which includes the steps of generating a braking force in drive wheel brake devices when it is determined that a drive wheel shows a slipping tendency, wherein the control mode for left and right drive wheel brake devices is switchable between an independent mode for independently controlling braking forces in the left and right drive wheel brake devices and a collective control mode for collectively controlling braking forces of these brake devices, and controlling the braking forces of the brake devices in the independent control mode in response to a condition in which the absolute value of a difference between left and right drive wheel speeds exceeds a predetermined value.

Abstract: A traction control method for a vehicle, includes the steps of comparing the amount of driven wheel speed (V.sub.W) changed per unit time with a reference deceleration (.DELTA.V.sub.R-) determined in correspondence to the lowest deceleration on a road surface of a lowest frictional coefficient which can be usually supposed, setting the vehicle speed (V.sub.R) equal to the driven wheel speed (V.sub.W), if the amount of driven wheel speed (V.sub.W) changed per unit time indicates a deceleration less than a reference deceleration (V.sub.R-); setting the vehicle speed (V.sub.R) equal to the last determined vehicle speed (V.sub.R(n-1)) corrected by the reference deceleration, if the amount of driven wheel speed (V.sub.W) changed per unit time indicates a deceleration greater than or equal to the reference deceleration (.DELTA.V.sub.R-); determining a slipping tendency of a driving wheel in a driving state at least in part by comparing a reference speed (V.sub.RH, V.sub.

Abstract: The present invention relates to a method for estimating vehicle speeds independently on front and rear wheels of a four-wheel motor vehicle on the basis of front wheel speeds and rear wheel speeds, for use as a basis for determining slip rates for front and rear wheels. According to the first method of the invention, a reference wheel speed determined by the vehicle speed as estimated from the left and right wheel speeds cannot be unnecessarily increased during turning of the vehicle. According to the second and third methods of the invention, the estimated vehicle speed largely does not deviate from the actual vehicle speed in the event of a phase difference of variants produced between the left and right wheels due to an anti-lock control during the turning of the vehicle.

Abstract: The present invention is a method for estimating the speed of a vehicle with antilock brake devices by obtaining a vehicle speed as a reference value for determining a slip ratio of a wheel based upon a wheel speed, an acceleration and a deceleration. At least the deceleration is based upon a differentiated value of a highest wheel speed from all wheels. In a vehicle in which the drive wheels are rigidly coupled, at least the deceleration is based upon a differentiated value of a highest value of the lowest wheel speed of the drive wheels and the wheel speeds of the driven wheels.