Toyota Jidosha Kabushiki Kaisha

Aisin Seiki Kabushiki Kaisha

Olympus Optical Company, Ltd.

Kaoru Ohashi

Shuuichi Buma

Toshio Onuma

Ken Asami

Masami Itou

Kazumasa Nakamura

Takahiro Nogami

Yoshihisa Nomura

Toshio Aburaya

Takashi Yonekawa

Hiroyuki Ikemoto

Akira Shirai

Kunihito Sato

Toshiaki Hamada

Masaki Kawanishi

Ikuya Kobayashi

Hiroaki Tanaka

Masakazu Ishikawa

Mizuho Sugiyama

Yuji Yokoya

Osamu Takeda

Hiroshi Miyata

Shin Koike

Hitoshi Araki

Masaru Ishikawa

Shinichi Tagawa

Kouichi Kokubo

Masanori Hirose

Hitoshi Iwata

Nobuyasu Suzumura

Hideki Kusunoki

Hiroshi Kawakami

Yutaka Hirano

Chiaki Hamada

Zensaku Murakami

Toshio Oonuma

Takami Sugiyama

Kinihito Sato

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.

In a hydraulic active suspension system, a plurality of actuators having working fluid chambers are provided corresponding to vehicle wheels. Each actuator is adapted to increase or decrease vehicle height in response to the hydraulic pressure within its working fluid chamber. The hydraulic pressures within the working fluid chambers are controlled to their desired pressure by associated pressure control devices. A desired pressure computing device is further provided. The computing device calculates the actual values of roll, pitch, heave and warp of a vehicle body from the vehicle heights detected by detecting devices and calculates the differences between the actual values and the associated values of roll, pitch, heave and warp determined by a desired attitude of the vehicle body to compute the desired pressures for the actuators. The degrees of the roll and/or pitch differences are set to be higher than that of the warp difference in contributing to the determination of the desired pressures.

Hydraulic active suspension system for a vehicle capable of enhancing

In a hydraulic active suspension system, a plurality of actuators having working fluid chambers are provided corresponding to vehicle wheels. Each actuator is adapted to increase and decrease vehicle height as the results of the supply and the discharge of working fluid to and from its working fluid chamber, respectively. Supplying and discharging devices supply working fluid to and discharge from the working fluid chamber. Vehicle height sensors detect the vehicle heights at the locations corresponding to the vehicle wheels. A control device is further provided. The control device controls the supplying and discharging devices so that the pressure within the working fluid chamber in each actuator may be a value corresponding to the sum of a basic pressure determined according to the running conditions of the vehicle and a compensating pressure determined based upon the integral value of the difference between a standard vehicle height and an actual vehicle height. When the integral value of the difference is larger in magnitude than a predeterminate value, it is reduced in magnitude by the control device so as to prevent the control with the compensating pressure from overriding the control with the basic pressure.

Hydraulic active suspension system for a vehicle capable of positively

A suspension pressure control system applies a pressure which is proportional to a current level supplied to a solenoid of a pressure control valve to a shock absorber associated with a suspension from the valve. When a pressure in a high pressure line which feeds a high pressure to the pressure control valve falls (rises), the pressure applied to the suspension is decreased (increased). Accordingly, the pressure in the high pressure line is detected by a sensor, and if it is low (high), the current level of the pressure control valve is corrected to a high value (low value). In order to prevent an abnormal pressure rise in the suspension which may be caused by an excessive pressure rise in the high pressure line during an idling operation of an engine, a correction which responds to the pressure of the high pressure line is chosen large when a vehicle speed is equal to zero or very low. In order to prevent an abnormality from occurring in the correction of the pressure which is attributable to an errorneous detected value during a failure of operation of sensor, such detected value is determined to be faulty, and in the event a fault occurred, the correction is modified to a given volume (0) which is allocated to a standard pressure in the high pressure line.

Pressure control system for suspension

In a system for controlling the US-OS characteristic of a vehicle having front and rear suspensions, a device for changing the US-OS characteristic is provided which is adapted to alter the roll stiffness distribution between the front and the rear suspensions. A turning state quantity is detected and the changing rate of a turning state quantity is determined. A control device is further provided which is adapted to respond to the turning state quantity and the changing rate of the turning state quantity, and to control the US-OS characteristic changing device so that the higher the changing rate of the turning state quantity is, the more the US-OS characteristic may be shifted toward higher over-steer, and for the same changing rate the higher the turning state quantity is, the more the US-OS characteristic may be shifted toward higher under-steer.

US-OS characteristic control system for a vehicle responding to turning

In a hydraulic suspension system, a plurality of actuators having working fluid chambers are provided. Each actuator is adapted to increase and decrease vehicle height as the results of the supply and the discharge of working fluid to and from its working fluid chamber, respectively. Working fluid supply passages supply working fluid at supply pressure to the working fluid chambers and working fluid discharge passages discharge working fluid from the working fluid chambers. Cut-off valves and pressure control devices are provided in the supply passages and the discharge passages. Each cut-off valve is adapted to remain in its closed position whenever the supply pressure is not more than a predetermined value. Each pressure control device is adapted to control the supply of the working fluid to and the discharge from the associated working fluid chamber to adjust the pressure within the chamber. The system further comprises devices for detecting the pressures within the working fluid chambers and a device for determining the supply pressure. The pressure control devices are controlled so that their controlling pressures may substantially be equal to the pressures within the associated working fluid chambers determined by the pressure determining devices at least until the cut-off valves are opened.

Hydraulic suspension system for a vehicle with less abrupt change in

Provided is a suspension controller which has a plurality of control sections in a control mechanism and which has the order of priority among the suspension controls when two or more different suspension controls are simultaneously instructed from the control sections, so as to optimally control the suspension characteristic according to both the road condition and the running condition of the vehicle. The suspension controller of the invention includes a preference mechanism or logic for preferentially altering the suspension characteristic to a harder state in order to reduce the vibration of the vehicle body and to prevent an abrupt change of the vehicle attitude, thus providing good control, high stability and riding comfort.

Suspension controller

Provided is a so-called active suspension controller for a vehicle especially effective during turning. The controller comprises: an actuator provided between the body and every wheel of the vehicle; sensors for a turning condition of the vehicle, here the turning condition including a steering angle, vehicle speed, yaw rate and others; and a control apparatus responsive to the sensed turning condition for driving the actuators in order to control the allotment ratio between the front and the rear axles of the load shift between the right and the left wheels. The allotted load shift realizes stable turning under various circumstances.

Suspension controller for improved turning

A suspension control system which provides a vehicle height signal representative of a vehicle height, a vehicle height data signal responsive to said vehicle height signal, and a first determination signal representative of a suspension characteristic alteration if a difference between a maximum and minimum value of said vehicle height data signal within a predetermined suspension characteristic alteration determination time interval exceeds a first value thereof, and which alters said suspension characteristic in response to said first determination signal. A suspension system which has a similar operation as said suspension system except that it provides a second determination signal representative of suspension characteristic restoration instead of a first determination signal if a difference between a maximum and minimum value of said vehicle height data signal within a first time interval of restoring determination is less than a second reference value thereof for a predetermined number of consecutive times, and which alters vehicle height.

Suspension control system

A suspension controller of a vehicle having a suspension between a body and a wheel, includes: a vehicle height detection means for detecting a vehicle height at a front wheel and for generating a vehicle height signal according to the detected height; a determination means for receiving the vehicle height signal, and for generating height data responsive to the vehicle height signal, for determining whether the difference between the maximum and the minimum value of the height data during a predetermined period is greater than a reference value, the period being determined within a cycle time of sprung mass vibration, and for generating a suspension control signal, and a suspension characteristic alteration means for altering characteristics of the suspension in response to the suspension control signal.

A suspension controller for a vehicle is provided to effectively absorb vibrations such as resonant vibration of the mass of the wheel when the wheel is not on the ground, namely, 'resonant vibration of unsprung mass'. The suspension controller includes: a vehicle height detection means at a front wheel; a vehicle height determination means for comparing the vehicle height with a predetermined reference value; a cycle time determination means for detecting the cycle time of the vehicle height signal and for comparing the detected cycle time with a predetermined reference value; a control means for generating a suspension characteristic alteration signal based upon the vehicle height determination result and the cycle time determination result; and a suspension characteristic alteration means for altering a suspension characteristic of the vehicle in response to the suspension characteristic alteration signal.

A near rear suspension controller for a vehicle having a suspension between a vehicle body and a rear wheel includes: a front height detection section for measuring a distance between the vehicle body and a front wheel for generating a front height signal; a judgement section for generating a judgment result signal when the front height signal exceeds a predetermined range; and a rear height control section for increasing the rear vehicle height when it receives the judgment result signal.

Rear suspension controller

When a sporadic shock due to a protrusion or sinking of a road surface is detected at front wheels of a vehicle during its cruising on the road surface, the characteristic of the rear wheel suspension of the vehicle is immediately altered to improve the controllability and the stability of the vehicle or the feel of the ride thereof. For that purpose, a height sensor for detecting the distance between the body of the vehicle and each of the right and left front wheels thereof, a judgement section by which a front wheel vehicle height signal generated by the height sensor is compared with a predetermined reference range signal, and a controller for altering the characteristic of the rear wheel suspension of the vehicle depending on the result of the comparison are provided. In addition, a returning control of the characteristic of the suspension to the original state immediately after the rear wheels of the vehicle have passed over the protrusion or sinking which causes a sporadic shock may be performed. More effective control can be performed if these section are provided for the right and left wheels of the front and rear of the vehicle, respectively.

Rear wheel suspension controller

A rear suspension controller for controlling the suspension characteristic of a vehicle having a suspension which supports a vehicle body on plural wheels, wherein the acceleration of the vertical movement of at least one of the front wheels is measured and a corresponding signal is produced for detecting sporadic irregularities on a road surface. This acceleration signal is compared against preset reference signals and the characteristic of the rear suspension is altered, e.g., the suspension is made harder or softer, in dependence on the comparison in order to keep the controllability and stability or to maintain a good ride comfort according to demand. Additionally, the preset reference signals themselves are changed depending upon the vehicle speed because the influence of the shock caused by the irregularities changes according to the vehicle speed.

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Okazaki, Japan

Kaoru Ohashi