Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Kabushiki Kaisha Toyota Chuo Kenkyusho

Kabushiki Kaisha Toyota Toyota Jidosha Kabushiki Kaisha

Osamu Takeda

Shuuichi Buma

Nobutaka Ohwa

Toshio Aburaya

Hajime Kamimae

Shunichi Doi

Takashi Yonekawa

Hideo Inoue

Hiroaki Tanaka

Kaoru Ohashi

Yoshihiko Tsuzuki

Mizuho Sugiyama

Satoshi Haseda

Shingo Urababa

Shin Koike

Masaru Ishikawa

Hitoshi Iwata

Akira Fukushima

Hideki Kusunoki

Kozo Fujita

Ichiro Akahori

Hiroyuki Hirano

A yaw-rate-sensor's anomaly detecting apparatus of the invention comprises a road-surface-condition determining device for determining a road surface condition and a yaw-rate-sensor's anomaly determining device for determining that a yaw rate sensor is abnormal, when a change amount of yaw rate outputted from the yaw rate sensor exceeds an anomaly determination threshold, wherein the yaw-rate-sensor's anomaly determining device sets one of different anomaly determination thresholds varying according to determination results by the road-surface-condition determining device. This can suppress erroneous determination of anomaly of the yaw rate sensor due to running on a bad road.

Apparatus for detecting anomaly of yaw rate sensor, and vehicle equipped

A steering angle detecting apparatus for accurately and surely detecting a steering angle of a motor vehicle. The apparatus is equipped with a turning angle detector for detecting a turning angle of a steering wheel of the motor vehicle. In addition, the apparatus estimates a turning angle of the steering wheel on the basis of the difference in speed between left and right wheels of the motor vehicle so as to calculate the difference in phase between the detection turning angle and the estimation turning angle. For detecting the accurate vehicle steering angle, the detection turning angle is corrected on the basis of the calculated phase difference therebetween.

Steering angle detecting apparatus for motor vehicles based on the phase

In a four-wheel steering system for an automotive vehicle, a travel speed of the vehicle is detected to determine parameter related to the detected vehicle speed, and lateral deviation of the vehicle is further detected to determine a steering angle of rear road wheels on a basis of the detected lateral deviation of the vehicle and the determined parameter. When the detected vehicle speed becomes unreliable due to skid condition of either one of the road wheels, the steering angle of the rear road wheels is determined on a basis of the detected lateral deviation and the fixed parameter.

Four-wheel steering system for automotive vehicle

A signal processing circuit for removing a noise component from a detection signal of a yaw-rate sensor for detecting a yaw rate generated in a motor vehicle. The processing circuit detects the magnitude of variation of the detection signal of the yaw-rate sensor so as to compare the magnitude of the detection signal with a predetermined reference value. In accordance with the comparison result, the processing circuit outputs a limitation detection signal to limit the variation to below the predetermined reference value. Further, when the magnitude of variation of the detection signal exceeds the predetermined reference value, the processing circuit outputs as the limitation detection signal the yaw rate detection signal immediately before the exceeding, and the predetermined reference value is corrected on the basis of the steering angular velocity of the steering wheel of the motor vehicle. This arrangement allows effectively eliminating a spear-like noise from the detection signal of the yaw-rate sensor.

Signal processing circuit for yaw-rate sensor

In an electric control apparatus for a four-wheel steering system including an electric motor the rotary angle of which is electrically controlled in accordance with a target steering angle of rear road wheels, and a hydro-mechanical tracer mechanism having a fluid control valve the valve element of which is drivingly connected to the electric motor to be displaced in proportion to the rotary angle of the electric motor, the tracer mechanism being arranged to steer the rear road wheels in proportion to a displacement amount of the valve element, the target steering angle is converted into a control value for rotation of the electric motor, and a drive signal indicative of the control value is applied to the electric motor. The electric control apparatus is designed to greatly change the control value to and from zero when the target steering angle is less than a predetermined small angle and to change the control value in proportion to the target steering angle when the target steering angle is more than the predetermined small angle.

Electric control apparatus for four-wheel steering system

An electric control apparatus for a four-wheel steering system is designed to calculate a rear wheel steering angle on a basis of a control rule corresponding with a steering mode selected from a plurality of rear wheel steering modes thereby to steer a set of dirigible rear road wheels at the calculated steering angle. The electric control apparatus is further designed to calculate a difference between new and old steering angles calculated when the selected steering mode has been changed to another one of the steering modes and immediately after change of the selected steering mode, to gradually decreasing an absolute value of the calculated difference at a predetermined time interval, to correct the new steering angle in accordance with the absolute value of the calculated difference until the absolute value becomes zero after change of the selected steering mode and to control an actual steering angle of the rear road wheels in accordance with the corrected new steering angle.

An electronic fluid suspension system having longitudinal acceleration sensor, acceleration difference calculation means and vehicle attitude control means in addition to other fluid flow control components known in the conventional suspension system. In this system, the vehicle attitude is controlled responsive to the difference between a maximum acceleration and a minimum acceleration detected within a predetermined time interval. When dive or squat of the vehicle body is anticipated by the difference, vehicle attitude control is performed, without inappropriately responding to a momentary change in the acceleration. After the vehicle attitude control, a return control is performed to restore the original attitude and, further, a vehicle attitude correction control is performed responsive to a difference in actual front/rear heights and corresponding original heights.

Electronic controlled fluid suspension system

An electronic controlled fluid suspension system in which a change in a vehicle attitude is expected in advance by an advance control means responsive to a driving state detected by a driving state detection means, and the current vehicle attitude is feedback-controlled by a feedback control means. The shares of the advance control amount and the feedback control amount are calculated by a share determination means so that final control amount is determined based on the shares. Fluid flow to and from the fluid suspension is controlled by a fluid flow control means in response to the final control amount. In such control system, the advance control and the feedback control are smoothly switched, which results in improved maneuverability and stability of the vehicle.

Electronic controlled fluid suspension system with an advance control

An electronic controlled suspension system detects a load on the fluid actuators and calculates a torsional load on the vehicle. Responsive to the calculated torsional load, corrective control is executed on the fluid flow to and from the fluid actuators, eliminating torsional load on the vehicle. Therefore, the driving characteristic is prevented from changing due to an unbalanced load on the vehicle. On the other hand, the electronic controlled suspension system detects a vehicle's cornering state. Responsive to the cornering state detected, control signals are output to increase the roll stiffness distribution to the front wheels. As a result, the roll stiffness distribution to the front wheels while the vehicle is about to corner becomes larger than that while the vehicle is steadily cornering. Responsive to the control signals, the vehicle attitude is controlled by supplying and discharging fluid to and from fluid actuators. Consequently, when the vehicle is just starting to corner, laterally moving load is controlled, and quick-responsive steering is realized.

An air pressure circuit comprising a compressor cylinder which is divided into two chambers by a slidable piston, a suction port and an exhaust port each, having a valve and mounted on one chamber of the cylinder, inhaling air of a pressure higher than that of atmospheric air form the suction port and exhausting the piston-compressed air from the exhaust port. The air pressure in the side of suction port is introduced from the other chamber of the cylinder.

Air pressure circuit

In controlling roll and pitch of a vehicle body responsive to a displacement signal produced at each wheel of the vehicle, each signal is low-pass-filtered with a certain threshold frequency to prevent hunting of the control due to an excessively high frequency component (such as noise or a component corresponding to road irregularities) of the signal. According to this invention, the threshold frequency is changed to a higher value in order to get quick attitude control when the roll or pitch of the body is expected, while it is set at a lower value when no such attitude change is expected in order to prevent hunting of the control.

Electronic controlled fluid suspension system for controlling roll and

An electronically controlled fluid suspension system for preventing the lateral roll of a vehicle computes a predetermined estimated lateral acceleration based on the running speed and the difference between the maximum steering angle and the minimum steering angle within a predetermined period. The supply and discharge of the air to and from the air springs is rapidly controlled corresponding to the estimated lateral acceleration so as to prevent the vehicle from rolling due to the steering operation. Moreover, the electronically controlled fluid suspension system computes a predetermined target vehicle height based on the lateral acceleration. After the air is supplied and discharged to and from the air springs and the increase of the lateral acceleration is stopped, the vehicle height is restored regardless of the external disturbance, by controlling the supply and discharge of the air corresponding to the vehicle height difference between the target vehicle height and the actual vehicle height.

Electronically controlled fluid suspension system

A vehicle fluid suspension circuit has an efficient cross-sectional area of the high pressure supply line is smaller than that of the low pressure exhaust line. The fluid supply and discharge speed can be equalized so that the vehicle height increasing speed and the vehicle height decreasing speed are equalized with each other, and the ride comfort is improved. Furthermore, the vehicle suspension circuit has two lines from fluid suspension to low pressure reserve tank are provided during fluid exhaust. A simplified construction can vary a speed of exhausted fluid from fluid suspension. Feeding and exhausting speeds, computation for the valve opening and closing time intervals is improved to be quite simple, and quick control is attained.

Vehicle fluid suspension circuit with equalized supply and discharge

An electronically controlled fluid suspension system detects an average longitudinal or lateral acceleration within a predetermined period, computes an acceleration difference between a maximum average acceleration and a minimum average acceleration. Based on the acceleration difference, an estimated longitudinal or lateral acceleration is computed. In response to the estimated longitudinal or lateral acceleration, computed are a height-raising quantity of a lowered portion of a vehicle and a height-lowering quantity of a raised portion thereof. The supply and release of a fluid to and from fluid springs is rapidly controlled so that the height-raising quantity of the lowered portion of the vehicle is less than the height-lowering quantity of the raised portion thereof. The electronically controlled fluid suspension system, thus, prevents the vehicle from inclining due to changes in driving status, and enhances a road-adherence ability on an uneven road as well as a steering stability.

An electronically controlled fluid suspension system for adjusting a vehicle's attitude rapidly controls the vehicle height: by providing and blocking the fluid communication between fluid springs and reserve tanks; and by shifting the damping force of shock absorbers to a higher degree in response to the change of the vehicle height. As a result, it can avoid the late control of the vehicle height and prevent the vibration of the vehicle body due to the vehicle height's adjustment, thereby enhancing riding comfort.

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Susono, Japan

Osamu Takeda