Mazda Motor Corporation

Mazada Motor Corporation

Tetsuro Butsuen

Tohru Yoshioka

Yasunori Yamamoto

Hiroki Uemura

Ayumu Doi

Tomohiko Adachi

Hiroshi Uchida

Kenichi Okuda

Satoshi Morioka

Tadayuki Niibe

Toshihiro Hara

Naotsugu Masuda

Kazuki Fujise

Ken-ichi Okuda

Norihiko Nakao

Takeshi Takagi

Satoru Matsuoka

Shinichiro Yamashita

Naoyuki Hikida

A suspension control system for feedback-controlling the sprung mass acceleration signal y.sub.m and a method for introducing the unsprung mass acceleration signal y.sub.L into a tuning circuit to tune gain of an FIR filter. In this system, tuning is performed so as to cancel the road surface input y.sub.m close to a reference frequency (around 10-12 Hz). As a result, the sprung mass acts as a dynamic damper upon the road surface input y.sub.m close to the reference frequency (around 10-12 Hz), however, frequency bands other than the reference frequency band do not receive the contribution of the second term in the equation (6). That is, output from the tuning circuit to an adder becomes almost zero, and normal sky-hook control is performed. Though the sprung mass system acts as a dynamic damper, the unsprung mass system exceeds the sprung mass system in mass, and excessive resonance does not occur.

Suspension apparatus with driving state feedback for vehicles

An automatic brake control system produces a warning before automatically making the braking action of a driving vehicle according to the velocities of the driving vehicle and the vehicle ahead. The system calculates the desired vehicle distance according to the velocities of the driving vehicle and the vehicle ahead, and sets a warning distance which is longer than the desired vehicle distance. The warning distance is set in accordance with the driver's feeling. According to the present invention, the system is prevented from producing undesirable warning.

Automatic brake control system

An integrated controller for a vehicle comprises a contact preventive device for detecting a distance between a vehicle and an obstacle and a relative speed, and deciding whether the vehicle may come in contact with the obstacle based on the results of detection so as to perform automatic braking or automatic steering, and a characteristic changing device for causing the suspension or steering characteristic of the vehicle to be changed. The control part of the characteristic changing device changes the suspension or steering characteristic based on information from the control part of the contact preventive device when operating the contact preventive device. In case the characteristic changing device is an active suspension device, the control part changes the suspension characteristic so as to increase a control gain when performing automatic braking and to inhibit the vehicle from being rolled when performing automatic steering. Consequently, it is possible to early change the suspension characteristic when operating the contact preventive device. Thus, the running stability of the vehicle can be enhanced.

Integrated controller for vehicle

The vehicle is provided with a radar unit for detecting an obstacle existing ahead in the course of the running way along which the vehicle is running. When the radar unit detects a variation in its detectable region, such as a detectable distance or a detectable area range in left and right directions, from the detectable region to be detectable during ordinary running, a safety unit such as an alarm unit or an automatic brake unit is operated. A control logic for operating a collision-avoiding system for avoiding a collision with the obstacle existing ahead, such as an alarm unit or an automatic brake unit, is altered to a safe side on which safety in driving the vehicle is improved, when the detectable region is varied.

Running-safety system for an automotive vehicle

Periodic first vibrations generated from the engine are reduced by the interference with the second vibrations generated from the speakers disposed in the vehicle compartment of the vehicle. The second vibrations are set in a cycle unit of the first vibrations, and they are corrected (optimized) on the basis of the signals from the microphones detecting the vibrations within the vehicle compartment and the transmission characteristic between the microphones and the speakers. During a transient period of time during which the cycles vary (during which the data lengths of the data of the second vibrations vary), such as by acceleration or deceleration, the data on the vibration wave form of the previous vibrations is corrected in anticipation (i.e. the data length is corrected), the current vibration wave form is set. The correction of the data length is made by inserting a given number of estimated data values into the previous data length or by deleting a given number of the data values from the previous data length. Further, the data length can be corrected by extending or contracting the previous vibration wave form as a whole so as to provide the data length in accordance with the current vibration wave form.

Vibration control system for an automotive vehicle

When the vehicle has deviated or is deviating from a lane on which the vehicle has been or is running, the deviation of the vehicle from the lane can be suppressed, for example, by allowing the steering wheel to be operatively rotated prior to an intention of the operator. The timing of suppressing the deviation of the vehicle can be altered in accordance with conditions including, for example, the existence of a lane in the direction of deviation of the vehicle on which another vehicle is running in the same direction, the existence of an obstacle in the direction of deviation of the vehicle, the existence of an adjacent lane in the direction of deviation of the vehicle on which another vehicle is running in the opposite direction, a state of the lane on which the vehicle is running, such as a curved lane or a straight lane, a direction of deviation is outside or inside the curved lane or a lane width, a vehicle speed, a steering angle of a steering wheel, an extent of vision, and so on.

Navigation control system with adaptive characteristics

An obstacle sensing apparatus for vehicles is provided in which detection of obstacles is performed efficiently by predicting the traveling path of the vehicle appropriately when detection of obstacles by a radar unit is limited to a region along the traveling path. The apparatus is provided with a radar unit for transmitting radar waves ahead of the vehicle and sensing obstacles present ahead of the vehicle, a steering angle sensor for sensing the steering angle of the vehicle, and a yaw rate sensor for sensing the yaw rate produced by the vehicle. First traveling-path predicting device predicts a traveling path of the vehicle based upon the steering angle, and second traveling-path predicting device predicts a traveling path of the vehicle based upon the yaw rate. One of these traveling paths is selected in dependence upon the operating state of the vehicle and detection of articles by the radar unit is carried out within a limited region along the traveling path selected.

Obstacle sensing apparatus for vehicles

A vehicle suspension device includes a shock absorber disposed between a sprung portion and an unsprung portion of a vehicle for each of the vehicle wheels, a damping force changing device for changing a damping characteristic of the shock absorber, a detecting device for detecting a difference in a damping force among the shock absorbers for respective wheels, and a control device for controlling the damping characteristic of the shock absorber so as to restrict the difference in the damping force among the wheels when the vehicle is in a specific running condition. Through the use of such a vehicle suspension device, diagonal vibration can be suppressed, improved running stability can be obtained and riding comfort can be improved.

Vehicle suspension device for stabilizing steering characteristics

A suspension system of a vehicle for calculating a product of the absolute speed zs of the sprung member and the relative speed zs-zu between the sprung member and the unsprung member and for controlling the damping force characteristic of the shock absorber to be higher if that product is more than the predetermined value and to be lower if the product is less than that value. An insensible range is formed for restricting switching of the damping force characteristic when .vertline.zs.vertline. and .vertline.zs-zu.vertline. are less than the predetermined value .delta.z, .delta.r, so that the damping force characteristic of the shock absorber is kept lower if .vertline.zs.vertline.&gt;.delta.z and .vertline.zs-zu.vertline. or .vertline.zs-zu.vertline.&lt;.delta.r and it is kept higher if .vertline.zs.vertline.&gt;.delta.z and .vertline.zs-zu.vertline. or .vertline.zs-zu.vertline.&lt;.delta.r. Through the above structure, unnecessary switching of the damping force characteristic of the shock absorber can be prevented without lowering the riding comfort and running stability. Also, a sensor for detecting oscillation frequency is not required, resulting in lesser cost.

Shock absorber having controlled damping force characteristics for use

A contact preventive system for vehicles using an automatic braking device and an automatic steering device together. Contact forecasting mechanism forecasts the contact of a vehicle with an obstacle. When the contact of the obstacle is forecasted, automatic braking control mechanism operates the automatic braking device. Environment detecting mechanism detects the change of environment such as a friction coefficient of a road. Automatic steering control mechanism operates the automatic steering device to alter the advance direction of the vehicle when a possibility of contact is caused by the change of environment during automatic braking. Thus, contact can be avoided.

Contact preventive apparatus for vehicles

A suspension system for a vehicle has shock absorbers, each provided so as to be associated with one wheel and between sprung parts and unsprung parts, step motors, each being adapted for changing damping force characteristics of one of the shock absorbers by open loop control, and a controller for outputting control signals to the step motors. The controller is adapted for outputting control signals every predetermined time interval so as to make the damping force characteristics of the shock absorbers harder. According to the thus constituted suspension system for a vehicle, it is possible to prevent the driving stability from being lowered even when at least one of the step motors is thrown out of synchronism.

Suspension system for vehicle

Disposed between a sprung element and an unsprung element is a shock absorber of multi-degree variable-damping-coefficient type. The change control of the damping coefficient is carried out so that an actual damping force generated by the shock absorber can harmonize with a target damping force, Fa. The foregoing target damping force, Fa, as functions of the sprung vertical displacement velocity Xs and the unsprung vertical displacement velocity Xu, is obtained by the formula: Fa=-Xs.multidot.gs-Xu.multidot.gu, wherein both gs and gu are coefficients and the relations of gs&gt;0; gu.gtoreq.0 hold. Thus, while controlling the sprung vertical motion, cushioning action of the wheels can be enhanced to improve traveling stabilization.

Automobile suspension including control of variable damping coefficient

In a suspension system for a vehicle comprising a shock absorber of which damping force characteristics can be changed into four or more characteristics, detecting means detect the oscillation frequency range of the sprung member of the vehicle and a bumpy road. From the four or more damping force characteristics of the shock absorber, the number of characteristics on the higher level side are limited to two or so when the sprung member is in a low frequency oscillation range, that of the characteristics on the lower level side are limited to two or so when the sprung member is in a high frequency oscillation range, and that of the characteristics on the medium level side are limited to two or so when a road is bumpy. The damping force characteristic of the shock absorber is selected and changed on the basis of a given control rule only within the limited damping force characteristics. Thus, it is possible to prevent noise and oscillation from being caused by the large change of the damping force characteristic. Furthermore, there can be obtained comfortableness to ride in and stability on a high level.

Suspension system for a vehicle

Disposed between a sprung element and an unsprung element is a shock absorber of multi-degree variable-damping-coefficient type. A damping coefficient of the shock absorber is changed so that an actual damping force generated by the shock absorber becomes equal to a target damping force that causes no sprung vertical motion. Such a change is inhibited when the difference between the damping force and the target force falls in the range of a predetermined value. The value is changed according to the magnitude of an damping coefficient now in selection of the shock absorber. This allows the shock absorber to effectively produce damping forces while at the same time preventing the damping coefficient from being changed too often to avoid the occurrence of chattering. Additionally, control delay due to the presence of a dead band zone is lessened. Traveling stabilization and riding comfort is improved.

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Hiroshima, Japan

Tetsuro Butsuen