Toyota Jidosha Kabushiki Kaisha

Aisin Seiki Kabushiki Kaisha

Masaki Yamamoto

Kenji Tozu

Shoji Inagaki

Takayuki Itoh

Norio Yamazaki

Noriaki Hattori

Jun Mihara

Shingo Sugiura

Takaji Umeno

Katsuhiro Asano

Shoji Ito

Yasushi Amano

Satoru Onozawa

Shusaku Fujimoto

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.

Device for estimating road friction state

A brake force distribution control system comprising wheel speed sensing means S1, S3 which detect wheel speeds VWFR, VWRR of a front right wheel FR and a rear right wheel RR respectively, standard speed calculating means M1 calculating first speed value B and second speed value C from each of the wheel speeds VWFR, VWRR, and figuring out front medium value of VWFR, B and C and rear medium value of VWFR, B and C as standard wheel speeds VWSFR, VWSRR respectively, comparison means M2 calculating a difference between the standard wheel speeds VWSRR and VWSFR and driving means M3 operating a pressure control valve unit FV depending on the differences so as to modulate brake force of the rear right wheel RR relative to that of the front right wheel FR.

Distribution system for selectively controlling and supplying brake

A vehicle speed control apparatus includes a detecting unit for detecting that a road holding ability relating to tires of an automotive vehicle during running operation has changed to be lower than a reference value, and a control unit for performing a vehicle speed control process when the change of the road holding ability is detected by the detecting unit, so as to prevent the vehicle speed from being excessively increased when the road holding ability is reduced.

Apparatus for controlling vehicle speed in response to a road holding

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.

Brake control apparatus for automotive vehicle that includes

An apparatus for estimating a slip angle in a wheeled vehicle having a set of front road wheels and a set of rear road wheels, including the same kind of wheel speed sensors arranged to detect each rotation speed of the road wheels for producing wheel speed signals respectively indicative of the detected rotation speeds of the road wheels, and a microcomputer responsive to the wheel speed signals from the sensors for calculating a first difference in speed between the front and rear road wheels and a second difference in speed between the left and right road wheels and for calculating a ratio of the first difference in speed relative to the second difference in speed for estimating the calculated ratio as a slip angle of the vehicle.

Electric control apparatus for control of the running characteristic of

Growing community of inventors

Kakegawa, Japan

Masaki Yamamoto