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: An antilock brake control system for a vehicle includes a PID calculating device for carrying out a PID calculation based on a deviation between a target slip rate determined based on a presumed vehicle speed and a slip rate, and the operation of a braking liquid pressure regulating device is controlled based on the result of the calculation in the PID calculating device. The PID calculating device is arranged to limit the PID calculation value within a predetermined limit value. Thus, it is possible to enhance the control followability in carrying out the control of a braking pressure based on the PID calculation.

Abstract: For cornering identification in an anti-lock control system and/or traction slip control system, wherein the rotational behavior of the wheels is measured and evaluated to determine a vehicle reference speed, and wherein criteria for cornering identification are derived from the wheel slip, the slip signals of the individual wheels are filtered and the signals sent are compared. Cornering is identified when simultaneously the filtered wheel slip on both front wheels is in excess of a predetermined maximum value and the filtered wheel slip values of one rear wheel exceed and that of the other rear wheel fall below a predetermined value. The threshold values depend on the vehicle reference speed. The direction of cornering is also identified.

Abstract: A brake control system which employs an antiskid control and wheel lock protection differential reference controller to provide antiskid and antilock brake control. The differential reference controller is capable of estimating both wheel velocity and vehicle velocity based on a single wheel speed sensor input. To reduce the effects of wheel speed noise, the differential reference controller estimates the wheel velocity and vehicle velocity by carrying out parallel processes using identical processing functions. The estimated wheel velocity and vehicle velocity are subtracted providing a differential output indicative of the slip velocity. Only unique parameters for each process, derived from physical constants, are different. In this way, the wheel speed noise is introduced into both processes and canceled when the results are subtracted to obtain the slip velocity.

Abstract: An anti-skid control device for braking a vehicle safely and quickly comprises a wheel speed sensor, a computer and an actuator for controlling brake fluid pressure in a wheel cylinder. The computer calculates, based on the wheel speed detected by the sensor, a wheel slip ratio relative to a road surface, a wheel speed acceleration and a gradient of the wheel speed acceleration, and controls the actuator so that it increases, decreases or holds the brake fluid pressure according to the data calculated. The brake fluid pressure is decreased to avoid locking of the wheel when the slip ratio exceeds a predetermined value, the wheel speed acceleration is below a predetermined value and the gradient of the wheel speed acceleration becomes lower than the predetermined level. In this manner, the brake fluid pressure is not decreased unnecessarily, and a desirable anti-skid control is achieved for braking the vehicle quickly and safely.

Abstract: An antilock brake control system in a vehicle includes a PID calculating device for carrying out a PID calculation based on a deviation between a target slip rate determined based on a presumed vehicle speed and a slip rate, so that the operation of braking fluid pressure regulating device is controlled based on the result of the calculation in the PID calculating device. In the antilock brake control system, a braking pressure control mode is decided based on the result of comparison of a PID calculation value calculated in the PID calculating device with a predetermined threshold value, so that the operation of braking fluid pressure regulating device is controlled in such control mode. When the amount of variation in PID calculation value within a predetermined time exceeds a predetermined value, a control mode different from a control mode decided from a current PID calculation value is selected.

Abstract: The present invention is directed to a vehicle motion control system for maintaining vehicle stability by controlling the braking force applied to at least one wheel of a vehicle. A vehicle condition monitor is provided for monitoring a condition of the vehicle in motion. The braking force is applied by a braking apparatus to each wheel in response to depression of a brake pedal, and on the basis of an output of the monitor and irrespective of depression of the brake pedal. A control variable is provided for actuating the braking apparatus and set in accordance with at least a first parameter (e.g., wheel acceleration) and a second parameter (e.g., slip rate) which are provided on the basis of the output of the monitor, respectively, so that the control variable is varied in response to the output of the monitor. The control variable is integrated during the braking apparatus is actuated.

Abstract: A brake control system for controlling an amount of braking force applied to a wheel of a vehicle running on a surface, comprising a sensor for measuring a speed of the wheel and for providing an output signal indicative of the speed; and a controller, operatively coupled to the sensor, which implements a Kalman filter to estimate an amplitude and location of a peak in a mu-slip curve representative of a coefficient of friction between the wheel and the surface based on the output signal of the sensor, and which controls the amount of braking force applied to the wheel based on the amplitude and location of the peak.

Abstract: A vehicle chassis system control method, comprising the steps of: measuring vehicle yaw rate, vehicle speed, and vehicle lateral acceleration; determining, responsive to the yaw rate, vehicle speed and lateral acceleration, an index ratio; comparing the index ratio to a predetermined threshold indicating a limit above which active chassis control is not desired; and responsive to the comparison, setting a signal indicating termination of active chassis control if the index ratio is above the predetermined threshold.

Abstract: In an antilock brake device, a determining function of which the sign varies when a wheel slip ratio is identical to a target value, and a switching function comprising an integral term which is a time integral of the determining function, are set, and a brake torque target value is determined so that it is proportional to the switching function. Alternatively, the brake torque target value computed according to the determining function is corrected according to a wheel angular acceleration. In this way, a brake torque or the wheel slip ratio between a road surface and tires is precisely controlled.

Abstract: A turn behavior control system continually modifies its control performance by itself so as to adapt itself to varying external conditions such as curving and surface conditions of the road and the driving skill of the driver, according to study of the turn behavior of the vehicle controlled thereby under the influence of those external conditions, such that an anti-spin moment is generated according to a spin parameter estimating the spinning condition of the vehicle when the spin parameter exceeds a standard value which is reviewed by each unit period to be lowered as the frequency of operation of the control system during the unit period increases or to be raised as the time based integration of the spin value during the unit period increases, or the anti-spin moment is increased as the friction coefficient of the road surface lowers.

Abstract: A technique to indicate a different-diameter wheel such as a temporary tire and to accurately correct the wheel speed of the different-diameter wheel is determined. Wheel speeds of a pair of left and right driven wheels are detected by wheel speed sensors and wheel speeds of a pair of left and right follower wheels are detected by wheel speed sensors. Yaw rates are calculated from the wheel speeds of the left and right wheels, and yaw rates are calculated from the wheel speeds of the wheels located diagonally. Which wheel of the four wheels is a different-diameter wheel is determined based on the magnitudes of the four yaw rates and the wheel speed of the different-diameter wheel is corrected based on a ratio in wheel speed between the different-diameter wheel and the other wheels.

Abstract: The invention is directed to an arrangement for controlling a braking force applied to each of front and rear road wheels of a vehicle depending upon a braking condition, with a hydraulic braking pressure supplied to each of the wheel brake cylinders through an actuator. The actuator is controlled by a braking force controller into which output signals of wheel speed sensors are fed. On the basis of the wheel speeds detected by the sensors, an estimated vehicle speed is calculated, and then a varying rate of the estimated vehicle speed is calculated. Furthermore, a wheel speed differential between the front and rear road wheels (or, a wheel slip rate differential therebetween) is calculated. Only when the wheel speed differential (or, the wheel slip rate differential) exceeds a predetermined value, the varying rate of the estimated vehicle speed is compared with a standard rate to estimate a coefficient of friction of the road surface.

Abstract: A brake system control for use in a vehicle that calculates a wheel slip for at least one wheel, wherein the brake system control comprises the steps of: monitoring the calculated wheel slip; imposing a discriminating criteria on the monitored wheel slip wherein the discriminating criteria determines whether or not the calculated wheel slip accurately reflects an actual operating condition of the wheel; implementing ABS control using an adjusted wheel slip for the wheel when the discriminating condition determines that the calculated wheel slip does not accurately reflect an actual operating condition of the wheel; and implementing ABS control utilizing the calculated wheel slip when the discriminating condition determines that the calculated wheel slip accurately reflects an actual operating condition of the wheel.

Abstract: A control system for use with an electronically-controlled automatic transmission provides for accurate determination of a full stop of a vehicle. The control system includes a device for computing the vehicle speed on the basis of a signal from a vehicle speed sensor, a device for determining whether or not the brake pedal is depressed, a device for computing deceleration from a first predetermined vehicle speed to a second predetermined, extremely low vehicle speed when the brake has been determined to be depressed, and a device for determining an estimated vehicle stop time starting with detection of the extremely low vehicle speed and ending with full stop of the vehicle, the estimated vehicle stop time corresponding to the above-computed deceleration.

Abstract: An ABS which evaluates slip values prescribes pressure values for the wheel brakes. In order to improve the driving stability, these pressure values are varied by a brake controller using the deviation of the yawing speed from a set value and the front-axle steering angle as input variables. The brake controller determines its output values (variation values) with the aid of the fuzzy logic. Additionally, rear-axle steering is integrated into the system, the system partially also using fuzzy logic. Subsequently, an adaptation which is based on fuzzy logic and uses the brake controller and the rear-axle steering controller in a weighted fashion is proposed.

Abstract: A braking force acting on the wheel is actuated by a very small amount at a resonant frequency of a vibrating system comprised of a vehicle body, a wheel, and road surface, and the amplitude of the resonant-frequency component of the wheel speed is detected. A gain in the amplitude of the resonant-frequency component of the wheel speed with respect to the amplitude of the very small actuation of the braking force is determined. A mean braking force is controlled to decrease when the gain is smaller than a reference value, and to increase when the gain is greater than the reference value.

Abstract: The ABS is provided with a modulator, and when the ABS is activated, control of the caliper pressure by the driver, is modified by the operation of the modulator having the aforementioned inlet valve (normally closed to a pressurized fluid source) and aforementioned outlet valve (normally open to a fluid exit), both controlled by the above-described control logic circuit. The modulator increases or decreases the caliper pressure, in response to changes in the pressurized fluid, regulated by such valves. Depending on the operation of the control logic circuit described above, three events may occur. When the inlet and outlet valves are not operated (i.e. their normal state), the modulator releases pressurized fluid through the output valve, and increases caliper pressure, to increase braking up to a predetermined maximum. If only the outlet valve is operated (i.e. both the inlet and outlet valves are closed), the modulator remains in a constant state and likewise, the caliper pressure is kept constant.

Abstract: A vehicle yaw control for a vehicle having wheel brakes wherein the wheel brakes complement driver controlled steering efforts by establishing a maximum steering angle that can be used for any given coefficient of friction at the wheel-road interface and for any given speed, thereby achieving optimum lateral control during turning maneuvers by compensating for under-steering and over-steering for each driving condition.

Abstract: A slip rate at a time when a wheel deceleration corresponding to the difference between the road-surface reactive torque and the braking torque has become greater than or equal to a predetermined value set on the basis of a vehicle deceleration is computed. An offset amount between the slip rate computed on the basis of the wheel deceleration and a targeted slip rate at which a coefficient of braking friction becomes maximum is computed. A wheel speed at the targeted slip rate is calculated as a targeted wheel speed on the basis of the calculated slip rate, the calculated offset amount, and a vehicle speed. Then, the braking torque of the wheel is controlled such that the wheel speed becomes equal to the targeted wheel speed.

Abstract: A method and system for damping wheel speed oscillation during an anti-lock braking event. The method includes the initial step of sensing the wheel speed and determining a wheel slip based on the sensed wheel speed and a vehicle speed reference. Next, the method continues with the step of determining whether the wheel slip has exceeded a predetermined slip threshold. If the wheel slip has not exceeded a predetermined slip threshold, the method performs normal or unmodified anti-lock brake control. If the wheel slip has exceeded the predetermined slip threshold, the method continues with the step of determining whether an acceleration feedback condition representative of a high mu surface has been satisfied. If an acceleration feedback condition has been satisfied, the method continues with the step of increasing brake pressure applied to the wheel from a steady-state level in a step-wise function during acceleration of the wheel before the wheel speed reaches the vehicle speed reference.

Abstract: The invention relates to a method for controlling vehicle brake pressure as a function of the deviation of the actual slip of wheels relative to a prescribed desired slip. The desired slip is determined from the wheel speeds in such a way that the cornering forces occurring between wheel and roadway given the specific desired slip values and the adhesion conditions occurring, ensure stable handling.

Abstract: A brake pressure controller, responsive to a wheel speed sensor and coupled to a brake, performs a cyclic control of pressure applied to the brake. A brake pressure cycle includes a pressure apply stage and a pressure dump stage having activation conditions based upon a slip threshold parameter. A predetermined base threshold quantity is modified in dependence upon a measured time duration of the pressure dump stage and/or a slip depth error quantity so that a greater amount of slip is added to the base slip threshold when braking on a deformable surface than when braking on a non-deformable surface.

Abstract: In an electric control apparatus for a hydraulic brake control system of a vehicle, a feedback control portion is provided to produce a feedback control pulse signal indicative of a difference between a target slip ratio and an actual slip ratio. A feedforward control portion is provided to successively convert the target slip ratio in relation to a required braking force, a hydraulic braking pressure and an amount of hydraulic braking fluid, in sequence, and to convert the amount of hydraulic braking fluid into a feedforward control pulse signal. A pulse mixing circuit is connected to control portions to mix the control pulse signals for producing a mixed control pulse signal as a distinct control pulse signal. A driving circuit is connected to the pulse mixing circuit to control a hydraulic braking pressure applied to each wheel of the vehicle in accordance with the control pulse signal, regardless of the extent to which a brake pedal of the vehicle is depressed.

Abstract: An anti-skid braking method is provided for controlling, on the basis of a slip ratio of a wheel and an acceleration of the wheel, braking force to be applied to the wheel. The anti-skid braking method comprises the following steps: where the slip ratio is found to fall outside an appropriate range during slip ratio computation, adding differences between a limit defining the appropriate range and the respective slip ratio values so computed; and when the integral of the differences is at least equal to a predetermined value and the acceleration of the wheel is detected to be low, enhancing the control of the braking force, the control being performed based on the wheel acceleration and the slip ratio, so that the slip ratio is brought back into the appropriate range. An anti-skid braking system suitable for use in practicing the anti-skid braking method is also described.

Abstract: An anti-skid control system for use in an automotive vehicle comprises a brake detecting device for detecting a braking operation of the vehicle, a deceleration detecting device for detecting an deceleration of a road-wheel during the braking operation, and a control device for controlling the braking operation in order to establish the maximum value of the deceleration. Independent of a surface of a road, the minimum braking distance is obtained.