Abstract: A vehicular anti-skid control apparatus comprises a differential pressure detector for detecting the pressure difference inside brake lines of separate brake channels, a brake failure detector for detecting failure in one of the brake channels based on the anti-skid control state of each brake channel, a brake failure evaluator for evaluating failure of the brake system based on both output signals of the differential pressure detector and brake failure detector wherein the anti-skid control method is changed from normal anti-skid control to a particular anti-skid control when a brake failure occurs.

Abstract: An antiskid control apparatus for vehicles having a part-time four-wheel drive mode. The antiskid control apparatus calculates an average front wheel speed and an average rear wheel speed. A difference between the average front wheel speed and average rear wheel speed is determined, and is filtered to obtain a smoothed wheel speed difference value. Based on the value of the smoothed wheel speed difference value, a determination is made whether the vehicle drive state is the two-wheel drive state or four-wheel drive state. The antiskid control of the vehicle is switched between two-wheel control and four-wheel control in accordance with the determined vehicle drive state.

Abstract: An apparatus for detecting wheel speed in a motor vehicle. The apparatus includes first, second, and third sensors for outputting pulse signals in response to rotations of rotary shafts of front left and right wheels and a drive shaft, respectively, and a rotational angular velocity calculating member for calculating first, second, and third rotational angular velocities of the first and second rotary shafts and the drive shaft from the pulse signals, respectively.

Abstract: A zero-point correction device for a gravity-type accelerometer employed in a vehicle having wheels, includes a calculator for calculating an estimated vehicle acceleration Aw based on the wheel speed, and a detector for detecting a gravitationally detected acceleration Am based on said gravity-type accelerometer. A subtractor is provided for subtracting a correction amount Ao obtained in each operation cycle from the gravitationally detected acceleration Am to produce a corrected acceleration Ac which is a corrected version of said gravitationally detected acceleration Am. The correction amount Ao for the present operation cycle is obtained by adding to the correction amount Ao obtained in the previous cycle, a value commensurate with a difference between the estimated vehicle acceleration Aw and the corrected acceleration Ac.

Abstract: A vehicle travel direction estimating device is provided which has a wheel speed calculating device for calculating the speed and acceleration Aw of a vehicle. In addition, a gravity-type accelerometer is provided for producing a gravitationally detected acceleration Am. When both Aw and Am increase or decrease simultaneously, it is determined that the vehicle is travelling forward, and when one of Aw and Am increases while the other decreases, it is determined that the vehicle is travelling in reverse. To detect this feature, a calculating system is provided to form differential values Daw and Dam from accelerations Aw and Am. The vehicle travel direction is estimated using the differential values Daw and Dam.

Abstract: A device for calculating estimated vehicle acceleration and speed for use in estimating vehicle speed Vv and vehicle acceleration Av, such that a subservient acceleration Az based on the wheel speed is used when As>Az during acceleration or when As<Az during deceleration, while the substitute acceleration As based on the gravity-type accelerometer is used in place of Az when As<Az during acceleration or when As>Az during deceleration.