JP3779441B2 - Vehicle collision avoidance control device - Google Patents

Vehicle collision avoidance control device Download PDF

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Publication number
JP3779441B2
JP3779441B2 JP19808897A JP19808897A JP3779441B2 JP 3779441 B2 JP3779441 B2 JP 3779441B2 JP 19808897 A JP19808897 A JP 19808897A JP 19808897 A JP19808897 A JP 19808897A JP 3779441 B2 JP3779441 B2 JP 3779441B2
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Prior art keywords
vehicle
tire
collision
actuator
load
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JP19808897A
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JPH1134629A (en
Inventor
圭 忍田
正樹 伊沢
秀明 渋江
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Honda Motor Co Ltd
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Honda Motor Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
    • B60G2202/40—Type of actuator
    • B60G2202/41—Fluid actuator
    • B60G2202/413—Hydraulic actuator
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
    • B60G2202/40—Type of actuator
    • B60G2202/41—Fluid actuator
    • B60G2202/414—Fluid actuator using electrohydraulic valves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/60—Load
    • B60G2400/61—Load distribution
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/80—Exterior conditions
    • B60G2400/82—Ground surface
    • B60G2400/823—Obstacle sensing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2500/00—Indexing codes relating to the regulated action or device
    • B60G2500/30—Height or ground clearance
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
    • B60G2600/18—Automatic control means
    • B60G2600/182—Active control means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
    • B60G2600/18—Automatic control means
    • B60G2600/187—Digital Controller Details and Signal Treatment
    • B60G2600/1875—Other parameter or state estimation methods not involving the mathematical modelling of the vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
    • B60G2800/22—Braking, stopping
    • B60G2800/222—Braking, stopping during collision
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
    • B60G2800/70—Estimating or calculating vehicle parameters or state variables
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
    • B60G2800/90—System Controller type
    • B60G2800/91—Suspension Control
    • B60G2800/914—Height Control System

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  • Fluid-Damping Devices (AREA)
  • Control Of Driving Devices And Active Controlling Of Vehicle (AREA)
  • Regulating Braking Force (AREA)
  • Vehicle Body Suspensions (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、自車と進路上の障害物との間の距離に応じて自動的に制動装置を作動させることのできる車両衝突回避制御装置に関するものである。
【０００２】
【従来の技術】
自車と進路上の障害物との間の距離をレーダー手段にて計測し、この計測データに応じて車両の制動装置を自動制御して衝突を回避するようにしたレーダーブレーキシステムが既に提案されている（特開平８−３１８８００号公報参照）。
【０００３】
【発明が解決しようとする課題】
一方、タイヤのグリップ力Ｆは、タイヤと路面との間の摩擦係数μとタイヤの接地面に加わる垂直荷重Ｗとの積（Ｆ＝μＷ）で与えられる。すなわち制動力の限界は、本質的にタイヤと路面間の摩擦係数で定まってしまう。そのため、上記のレーダーブレーキシステムにおいて、乾燥路面を基準に制動距離を設定すると、例えば氷結路や砂利道などのようにタイヤのグリップ力が著しく低下する路面では制動距離が不十分となり、衝突回避能力が低下してしまう。しかしながら、走行する機会が圧倒的に少ない低μ路を制動距離の設定基準にすることは、通常走行時の車間距離が過大となることに繋がり、ひいては渋滞の原因となりかねないので好ましくはない。
【０００４】
本発明は、このような従来技術の問題点を解消するべく案出されたものであり、その主な目的は、特定の状態時に制動距離をより一層短縮化することの可能な車両衝突回避制御装置を提供することにある。
【０００５】
【課題を解決するための手段】
このような目的を果たすために、本発明においては、自車と進路上の障害物との間の距離に応じて自動的に制動装置を作動させた際に制動距離が不足すると判断された場合には、車体とタイヤとの間を連結するアクチュエータの伸張加速度で車体に上下方向の慣性力を発生させ、その反力により、タイヤのグリップ力を決定する１つのファクターである接地荷重を一時的に増大させるものとした。これにより、低μ路におけるタイヤのグリップ力が増大するので、より大きな制動力を加えることができることとなり、制動距離の短縮化が可能となる。
【０００６】
【発明の実施の形態】
以下に添付の図面を参照して本発明の構成について詳細に説明する。
【０００７】
図１は、本発明が適用される能動型懸架装置の要部の概略構成を模式的に示している。タイヤ１は、上下のサスペンションアーム２・３により、車体４に対して上下動可能に支持されている。そして下サスペンションアーム３と車体４との間には、油圧駆動によるリニアアクチュエータ５が設けられている。
【０００８】
リニアアクチュエータ５は、シリンダ／ピストン式のものであり、シリンダ内に挿入されたピストン６の上下の油室７・８に可変容量型油圧ポンプ９から供給される作動油圧をサーボ弁１０で制御することにより、ピストンロッド１１に上下方向の推力を発生させ、これによってタイヤ１の中心（車軸）と車体４との間の相対距離を自由に変化させることができるようになっている。
【０００９】
ポンプ９からの吐出油は、ポンプ脈動の除去および過渡状態での油量を確保するためのアキュムレータ１２に蓄えられた上で、各輪に設けられたアクチュエータ５に対し、各アクチュエータ５に個々に設けられたサーボ弁１０を介して供給される。
【００１０】
この油圧回路には、公知の能動型懸架装置と同様に、アンロード弁１３、オイルフィルタ１４、逆止弁１５、圧力調整弁１６、およびオイルクーラ１７などが接続されている。
【００１１】
なお、サーボ弁１０は、電子制御ユニット（ＥＣＵ）１８から発せられる制御信号をサーボ弁ドライバ１９を介してソレノイド１０ａに与えることにより、油圧アクチュエータ５に与える油圧と方向とが連続的に制御されるものであり、車体４とピストンロッド１１との接続部に設けられた荷重センサ２０、車体４と下サスペンションアーム３との間に設けられたストロークセンサ２１、車体側の上下加速度を検出するばね上加速度センサ２２、およびタイヤ側の上下加速度を検出するばね下加速度センサ２３の信号をＥＣＵ１８で処理した信号に基づき、図２に示す制御アルゴリズムに従って制御される。
【００１２】
次に本発明の制御アルゴリズムについて説明する。先ず、公知のレーダー手段２７にて自車の進路を走査する（ステップ１）。これによって障害物の存在を検知した場合は、その時の車速を車速センサ２８から読み込み（ステップ２）、障害物までの距離と車速とから衝突懸念度演算手段２９にて衝突の可能性を判断する（ステップ３）。ここでそのままの速度で進行すると衝突すると判断された場合は、制動装置３０を作動させて減速させる（ステップ４）。次いで例えば車速を微分するか或いは加速度センサにて減速度を求め（ステップ５）、予め設定しておいた標準路面上で制動装置３０が発生し得る基準減速度と実際に得られた減速度とを比較し、現状の減速度で衝突を回避し得るか否かを判断する（ステップ６）。乾燥路面ならば基準減速度と実減速度とは概ね一致するが、路面μが小さい場合は実減速度が基準減速度を下回るので、基準減速度と実減速度とを比較することにより、衝突を回避し得るか否かを判断できる。ここで衝突懸念が解消されていないと判断された場合は、各タイヤの懸架装置に設けられたばね上加速度センサ２２とばね下加速度センサ２３との目標荷重演算部２４への入力信号を参照して仮の目標荷重を内部的に発生させ、この値と荷重センサ２０の信号（実荷重）との偏差を演算し、この差分を安定化演算部２５で処理した後、変位制限比較演算部２６でストロークセンサ２１の信号を参照してアクチュエータ５のストロークの限界内での制御が行われるようにサーボ弁ドライバ１９に与える指令値を調整する。そしてこの調整された信号により、目標荷重と実荷重とが等しくなるようにサーボ弁１０を駆動してアクチュエータ５に伸張加速度を発生させ、車体に上下方向の慣性力を発生させる（ステップ７）。これにより、タイヤの接地荷重が増大してタイヤのグリップ力が一時的に増大するので（図３参照）、ロック限界が引き上げられて制動距離が短縮される。
【００１３】
なお、図３は、タイヤの接地荷重（＝グリップ力）分布を概念的に示し、静荷重の範囲での接地荷重を実線の円で表し、アクチュエータ５のストローク制御で増大した接地荷重を二点鎖線の円で表している。図３は、全輪の接地荷重を増大させた場合を例示しているが、これはその時の状況に応じて最も安定に停止し得ると判断される車輪に対応するアクチュエータを個々に制御すれば良いことは言うまでもない。
【００１４】
次に本発明の原理について説明する。図４のモデルにおいて、
Ｍ2：ばね上質量
Ｍ1：ばね下質量
Ｚ2：ばね上座標
Ｚ1：ばね下座標
Ｋt：タイヤのばね定数
Ｆz：アクチュエータ推力
とし、下向きを正方向とすると、ばね上質量Ｍ2並びにばね下質量Ｍ1の運動方程式は、それぞれ次式で与えられる。ただし式中の＊マークは一階微分を表し、＊＊マークは二階微分を表す。
Ｍ2・Ｚ2＊＊＝−Ｆz
Ｍ1・Ｚ1＊＊＋Ｋt・Ｚ1＝Ｆz
【００１５】
従って、タイヤ接地荷重Ｗは次式で与えられる。
Ｗ＝−Ｋt・Ｚ1＝−Ｆz＋Ｍ1・Ｚ1＊＊
＝Ｍ2・Ｚ2＊＊＋Ｍ1・Ｚ1＊＊
【００１６】
つまり接地荷重Ｗは、ばね上慣性力とばね下慣性力との和となるので、アクチュエータ５の伸縮加速度を制御してばね上質量とばね下質量との少なくともいずれか一方の慣性力を変化させることにより、接地荷重Ｗを変化させることができる。従って、アクチュエータ５の伸張加速度を制御することにより、接地荷重Ｗをタイヤ毎に一時的に増大させることが可能となる。なお、サスペンションストロークを２００mmとしてアクチュエータ５に１トンの推力を発生させた場合、約０．２秒間作動させることができる。
【００１７】
一般的には、アクチュエータの消費エネルギを節約するために車両重量を支持する懸架スプリングと減衰力発生用ダンパとを併用するが（図５参照）、その場合は、
Ｋs：懸架スプリングのばね定数
Ｃ：ダンパの減衰係数
とすると、ばね上質量Ｍ2並びにばね下質量Ｍ1の運動方程式は、それぞれ次式で与えられる。
Ｍ2・Ｚ2＊＊＋Ｃ・（Ｚ2＊−Ｚ1＊）＋Ｋs・（Ｚ2−Ｚ1）＝−Ｆz
Ｍ1・Ｚ1＊＊＋Ｃ・（Ｚ1＊−Ｚ2＊）＋Ｋs・（Ｚ1−Ｚ2）＋Ｋt・Ｚ1＝Ｆz
【００１８】
従って、タイヤ接地荷重Ｗは次式で与えられる。
Ｗ＝−Ｋt・Ｚ1
＝−Ｆz＋Ｍ1・Ｚ1＊＊＋Ｃ・（Ｚ1＊−Ｚ2＊）＋Ｋs・（Ｚ1−Ｚ2）
＝Ｍ2・Ｚ2＊＊＋Ｍ1・Ｚ1＊＊
【００１９】
つまり接地荷重Ｗは、上記と同様に、アクチュエータの伸縮加速度を制御することによって変化させることができることが分かる。
【００２０】
なお、上記実施例においては、アクチュエータとして油圧駆動のシリンダ装置を用いるものを示したが、これはリニアモータ或いはボイスコイルなどの如きその他の電気式の推力発生手段を用いても、あるいはカム機構やばね手段を用いて加速度を発生させても、同様の効果を得ることができる。
【００２１】
これに加えて、本発明の要旨を逸脱しない範囲で使用センサを簡略化することができる。例えば、ばね下、ばね上両加速度センサの出力差を二階積分することでも位置検出信号を得ることができるので、ストロークセンサを廃止することができるし、ばね上、ばね下両重量の実測値と、ばね下、ばね上両加速度センサの出力値とを演算することでアクチュエータが発生する力を求めることができるので、荷重センサを廃止することもできる。さらに、荷重センサと変位センサとの信号に基づいて状態推定器を構成し、ばね下、ばね上両加速度を間接的に求めることもできる。また、ＥＣＵについても、ディジタル、アナログ、並びにハイブリッドのいずれでも実現可能なことは言うまでもない。
【００２２】
【発明の効果】
このように本発明によれば、接地荷重を動的に増大させることでタイヤのグリップ力の発生限界を高めることができるので、路面の摩擦係数が低かったりして車輪の制動装置だけでは停止し得ないような場合でも制動距離を短縮化し得る。これに加えて、摩擦円の理論から言うと、タイヤの横力と前後力との総和は一定のため、旋回のために横力が費やされると、制動のための前後力が減少する傾向となるが、本発明によれば、制動力が不足ぎみなタイヤの接地荷重を増大させることができるので、旋回を含む時の衝突回避性能の向上にも効果的である。
【図面の簡単な説明】
【図１】本発明が適用される能動型懸架装置の概略システム構成図。
【図２】本発明の制御フロー図。
【図３】急制動時の概念的な接地荷重分布図。
【図４】本発明の原理を説明するためのモデル図。
【図５】一般的な能動型懸架装置のモデル図。
【符号の説明】
１ タイヤ
２ 上サスペンションアーム
３ 下サスペンションアーム
４ 車体
５ アクチュエータ
６ ピストン
７・８ 油室
９ 油圧ポンプ
１０ サーボ弁
１１ ピストンロッド
１２ アキュムレータ
１３ アンロード弁
１４ オイルフィルタ
１５ 逆止弁
１６ 圧力調整弁
１７ オイルクーラ
１８ 電子制御ユニット（ＥＣＵ）
１９ サーボ弁ドライバ
２０ 荷重センサ
２１ ストロークセンサ
２２ ばね上加速度センサ
２３ ばね下加速度センサ
２４ 目標荷重演算部
２５ 安定化演算部
２６ 変位制限比較演算部
２７ レーダー手段
２８ 車速センサ
２９ 衝突懸念度演算部
３０ 制動装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle collision avoidance control device capable of automatically operating a braking device in accordance with a distance between an own vehicle and an obstacle on a course.
[0002]
[Prior art]
A radar brake system has already been proposed in which the distance between the vehicle and the obstacle on the route is measured by radar means, and the braking device of the vehicle is automatically controlled according to the measured data to avoid a collision. (See JP-A-8-318800).
[0003]
[Problems to be solved by the invention]
On the other hand, the grip force F of the tire is given by the product (F = μW) of the coefficient of friction μ between the tire and the road surface and the vertical load W applied to the ground contact surface of the tire. That is, the limit of the braking force is essentially determined by the coefficient of friction between the tire and the road surface. Therefore, in the above radar brake system, when the braking distance is set based on the dry road surface, the braking distance becomes insufficient on the road surface where the grip force of the tire remarkably decreases, such as an icy road or a gravel road, and the collision avoidance ability Will fall. However, it is not preferable to use a low μ road that has an overwhelmingly low chance of driving as a reference for setting the braking distance, because it leads to an excessively large inter-vehicle distance during normal driving and may cause traffic jams.
[0004]
The present invention has been devised to solve such problems of the prior art, and the main object of the present invention is vehicle collision avoidance control capable of further shortening the braking distance in a specific state. To provide an apparatus.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, in the present invention, when it is determined that the braking distance is insufficient when the braking device is automatically operated according to the distance between the vehicle and the obstacle on the course. In this case, the inertial force in the vertical direction is generated in the vehicle body by the extension acceleration of the actuator that connects the vehicle body and the tire, and the ground load, which is one factor that determines the grip force of the tire, is temporarily generated by the reaction force. To be increased. As a result, the grip force of the tire on the low μ road increases, so that a larger braking force can be applied, and the braking distance can be shortened.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a configuration of the present invention will be described in detail with reference to the accompanying drawings.
[0007]
FIG. 1 schematically shows a schematic configuration of a main part of an active suspension device to which the present invention is applied. The tire 1 is supported by upper and lower suspension arms 2 and 3 so as to be movable up and down with respect to the vehicle body 4. A hydraulic actuator linear actuator 5 is provided between the lower suspension arm 3 and the vehicle body 4.
[0008]
The linear actuator 5 is of the cylinder / piston type, and the hydraulic pressure supplied from the variable displacement hydraulic pump 9 to the upper and lower oil chambers 7 and 8 of the piston 6 inserted in the cylinder is controlled by the servo valve 10. As a result, a vertical thrust is generated in the piston rod 11, whereby the relative distance between the center (axle) of the tire 1 and the vehicle body 4 can be freely changed.
[0009]
The oil discharged from the pump 9 is stored in an accumulator 12 for removing pump pulsation and securing the oil amount in a transient state, and then individually to each actuator 5 with respect to the actuator 5 provided on each wheel. It is supplied via a provided servo valve 10.
[0010]
An unload valve 13, an oil filter 14, a check valve 15, a pressure adjustment valve 16, an oil cooler 17, and the like are connected to this hydraulic circuit as in a known active suspension system.
[0011]
The servo valve 10 continuously controls the hydraulic pressure and direction applied to the hydraulic actuator 5 by providing a control signal generated from an electronic control unit (ECU) 18 to the solenoid 10a via the servo valve driver 19. A load sensor 20 provided at a connection portion between the vehicle body 4 and the piston rod 11, a stroke sensor 21 provided between the vehicle body 4 and the lower suspension arm 3, and a sprung for detecting vertical acceleration on the vehicle body side. Control is performed according to a control algorithm shown in FIG. 2 based on signals obtained by processing the signals of the acceleration sensor 22 and the unsprung acceleration sensor 23 for detecting the vertical acceleration on the tire side by the ECU 18.
[0012]
Next, the control algorithm of the present invention will be described. First, the course of the own vehicle is scanned by the known radar means 27 (step 1). When the presence of an obstacle is detected by this, the vehicle speed at that time is read from the vehicle speed sensor 28 (step 2), and the possibility of a collision is judged by the collision concern degree calculation means 29 from the distance to the obstacle and the vehicle speed. (Step 3). If it is determined that a collision occurs when the vehicle travels at the same speed, the braking device 30 is operated to decelerate (step 4). Next, for example, the vehicle speed is differentiated or the deceleration is obtained by an acceleration sensor (step 5), and the reference deceleration that can be generated by the braking device 30 on the standard road surface set in advance and the actually obtained deceleration are obtained. Are compared to determine whether or not a collision can be avoided with the current deceleration (step 6). If the road surface is dry, the standard deceleration and the actual deceleration are almost the same, but if the road surface μ is small, the actual deceleration is lower than the standard deceleration. It can be determined whether or not it can be avoided. Here, when it is determined that the concern about the collision has not been resolved, the input signals to the target load calculation unit 24 of the sprung acceleration sensor 22 and the unsprung acceleration sensor 23 provided in the suspension device of each tire are referred to. A temporary target load is generated internally, and a deviation between this value and the signal (actual load) of the load sensor 20 is calculated. After the difference is processed by the stabilization calculation unit 25, the displacement limit comparison calculation unit 26 The command value given to the servo valve driver 19 is adjusted so that the control within the stroke limit of the actuator 5 is performed with reference to the signal of the stroke sensor 21. Based on the adjusted signal, the servo valve 10 is driven so that the target load and the actual load are equal to generate an extension acceleration in the actuator 5, and an inertial force in the vertical direction is generated in the vehicle body (step 7). Thereby, the ground contact load of the tire increases and the grip force of the tire temporarily increases (see FIG. 3), so that the lock limit is raised and the braking distance is shortened.
[0013]
FIG. 3 conceptually shows the distribution of tire contact load (= grip force), the contact load in the static load range is indicated by a solid circle, and the contact load increased by the stroke control of the actuator 5 is two points. It is represented by a chain line circle. FIG. 3 exemplifies the case where the ground contact load of all the wheels is increased. This is because the actuators corresponding to the wheels that are judged to be able to stop most stably according to the situation at that time are individually controlled. It goes without saying that it is good.
[0014]
Next, the principle of the present invention will be described. In the model of FIG.
M2: Unsprung mass M1: Unsprung mass Z2: Unsprung coordinate Z1: Unsprung coordinate Kt: Spring constant of tire Fz: Actuator thrust, where the downward direction is positive, the motion of unsprung mass M2 and unsprung mass M1 Each equation is given by the following equation. However, the * mark in the formula represents the first derivative, and the ** mark represents the second derivative.
M2 ・ Z2 ** = −Fz
M1 / Z1 ** + Kt / Z1 = Fz
[0015]
Therefore, the tire ground contact load W is given by the following equation.
W = -Kt · Z1 = -Fz + M1 · Z1 **
= M2 / Z2 ** + M1 / Z1 **
[0016]
That is, since the ground load W is the sum of the sprung inertia force and the unsprung inertia force, the inertial force of the sprung mass or the unsprung mass is changed by controlling the expansion / contraction acceleration of the actuator 5. As a result, the ground load W can be changed. Therefore, the ground load W can be temporarily increased for each tire by controlling the extension acceleration of the actuator 5. When the suspension stroke is 200 mm and a thrust of 1 ton is generated in the actuator 5, it can be operated for about 0.2 seconds.
[0017]
Generally, in order to save energy consumption of the actuator, a suspension spring that supports the vehicle weight and a damper for generating a damping force are used in combination (see FIG. 5).
When Ks is the spring constant of the suspension spring and C is the damping coefficient of the damper, the equations of motion for the sprung mass M2 and the unsprung mass M1 are given by the following equations, respectively.
M2 · Z2 ** + C · (Z2 * -Z1 * ) + Ks · (Z2-Z1) = -Fz
M1 · Z1 ** + C · (Z1 * -Z2 * ) + Ks · (Z1-Z2) + Kt · Z1 = Fz
[0018]
Therefore, the tire ground contact load W is given by the following equation.
W = -Kt · Z1
= -Fz + M1 · Z1 ** + C · (Z1 * -Z2 * ) + Ks · (Z1-Z2)
= M2 / Z2 ** + M1 / Z1 **
[0019]
That is, it can be seen that the ground load W can be changed by controlling the expansion / contraction acceleration of the actuator, as described above.
[0020]
In the above embodiment, an actuator using a hydraulically driven cylinder device is shown. However, this may be achieved by using other electric thrust generating means such as a linear motor or a voice coil, a cam mechanism, The same effect can be obtained even if acceleration is generated using the spring means.
[0021]
In addition, the sensor used can be simplified without departing from the scope of the present invention. For example, the position detection signal can also be obtained by second-order integration of the output difference between the unsprung and unsprung acceleration sensors, so the stroke sensor can be eliminated, and the actual measured values of both the unsprung and unsprung weights can be used. Since the force generated by the actuator can be obtained by calculating the output values of the unsprung and unsprung acceleration sensors, the load sensor can be eliminated. Furthermore, a state estimator can be configured based on signals from the load sensor and the displacement sensor, and both unsprung and sprung accelerations can be obtained indirectly. Needless to say, the ECU can be realized by any of digital, analog, and hybrid.
[0022]
【The invention's effect】
As described above, according to the present invention, since the generation limit of the grip force of the tire can be increased by dynamically increasing the ground contact load, the road surface friction coefficient is low, and the wheel braking device alone stops. Even in such a case, the braking distance can be shortened. In addition to this, according to the theory of friction circles, the sum of the lateral force and longitudinal force of the tire is constant, and when lateral force is consumed for turning, the longitudinal force for braking tends to decrease. However, according to the present invention, since the ground contact load of the tire can be increased even when the braking force is insufficient, the collision avoidance performance when turning is also effective.
[Brief description of the drawings]
FIG. 1 is a schematic system configuration diagram of an active suspension device to which the present invention is applied.
FIG. 2 is a control flow diagram of the present invention.
FIG. 3 is a conceptual grounding load distribution diagram during sudden braking.
FIG. 4 is a model diagram for explaining the principle of the present invention.
FIG. 5 is a model diagram of a general active suspension system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tire 2 Upper suspension arm 3 Lower suspension arm 4 Car body 5 Actuator 6 Piston 7/8 Oil chamber 9 Hydraulic pump 10 Servo valve 11 Piston rod 12 Accumulator 13 Unload valve 14 Oil filter 15 Check valve 16 Pressure adjustment valve 17 Oil cooler 18 Electronic control unit (ECU)
19 servo valve driver 20 load sensor 21 stroke sensor 22 sprung acceleration sensor 23 unsprung acceleration sensor 24 target load calculation unit 25 stabilization calculation unit 26 displacement limit comparison calculation unit 27 radar means 28 vehicle speed sensor 29 collision fear degree calculation unit 30 braking apparatus

Claims (1)

車両の制動力を制御する制動力制御手段と、
自車と進路上の障害物との間の距離を計測し、該計測値から衝突懸念度を判断する衝突懸念度判断手段と、
車体と車軸との間の上下方向相対距離を能動的に変化させるアクチュエータの伸張加速度で車体に上下方向の慣性力を発生させ、その反力をタイヤの接地荷重に加える接地荷重制御手段とを有し、
前記衝突懸念度判断手段の判断に基づいて前記制動力制御手段を作動させた際に所望の減速度が得られない場合に前記接地荷重制御手段を作動させることを特徴とする車両衝突回避制御装置。Braking force control means for controlling the braking force of the vehicle;
A collision concern degree determination means for measuring a distance between the own vehicle and an obstacle on the course and determining a collision concern degree from the measured value;
There is a ground load control means that generates vertical inertial force on the vehicle body by the extension acceleration of the actuator that actively changes the vertical relative distance between the vehicle body and the axle and applies the reaction force to the tire ground load. And
A vehicle collision avoidance control device that activates the ground load control means when a desired deceleration cannot be obtained when the braking force control means is actuated based on the judgment of the collision concern degree judgment means. .
JP19808897A 1997-07-24 1997-07-24 Vehicle collision avoidance control device Expired - Fee Related JP3779441B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP19808897A JP3779441B2 (en) 1997-07-24 1997-07-24 Vehicle collision avoidance control device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19808897A JP3779441B2 (en) 1997-07-24 1997-07-24 Vehicle collision avoidance control device

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Publication number Priority date Publication date Assignee Title
JP3633284B2 (en) * 1998-06-11 2005-03-30 トヨタ自動車株式会社 Vehicle equipped with a vehicle height adjustment device
DE19923708B4 (en) * 1999-05-22 2012-03-08 Volkswagen Ag Motor vehicle with suspension and damping device and combined safety device
DE102006037428B4 (en) * 2006-08-09 2011-11-17 Benteler Automobiltechnik Gmbh Wheel suspension for a motor vehicle
JP4915268B2 (en) 2006-12-22 2012-04-11 株式会社エクォス・リサーチ Vehicle control device
US8814279B2 (en) 2009-10-14 2014-08-26 Toyota Jidosha Kabushiki Kaisha Brake system
KR101194152B1 (en) * 2010-10-05 2012-10-26 주식회사 만도 METHOD AND SySTEM FOR AVOIDING PEDESTRIAN COLLISION
JP7021959B2 (en) * 2018-01-18 2022-02-17 Ｋｙｂ株式会社 Hydraulic shock absorber

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