JP2591236B2 - Rear wheel steering system for front wheel drive vehicles - Google Patents
Rear wheel steering system for front wheel drive vehiclesInfo
- Publication number
- JP2591236B2 JP2591236B2 JP2076699A JP7669990A JP2591236B2 JP 2591236 B2 JP2591236 B2 JP 2591236B2 JP 2076699 A JP2076699 A JP 2076699A JP 7669990 A JP7669990 A JP 7669990A JP 2591236 B2 JP2591236 B2 JP 2591236B2
- Authority
- JP
- Japan
- Prior art keywords
- front wheel
- steering angle
- component
- rear wheel
- wheel steering
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は前輪駆動車の後輪操舵装置に関するものであ
る。Description: TECHNICAL FIELD The present invention relates to a rear wheel steering device for a front wheel drive vehicle.
（従来の技術） 後輪操舵装置は、前輪操舵時車両の小廻り性能や旋回
安定性を向上させるために後輪も操舵するものである。
この種装置としては従来より種々のものが提案されてき
たが、例えば特開昭63−287676号公報に記載の如く次式
が満足されるような後輪舵角δｒを与える技術がある。(Related Art) A rear wheel steering device also steers rear wheels in order to improve small turning performance and turning stability of a vehicle during front wheel steering.
This as a seed devices have been proposed are various conventionally, there is a technique to provide a wheel steering angle [delta] r after that for example the following equation as described in JP 63-287676 JP is satisfied.
但し δf:前輪舵角 T:後輪操舵系の１次遅れ時定数 K:比例定数 τ:1次微分定数 τ′:2次微分定数 S:ラプラス演算子 かかる後輪舵角制御において、比較定数Ｋは定常旋回
安定性の向上に寄与する後輪の同相（前輪と同方向の転
舵）成分（比例成分）を決定し、微分定数τ，τ′は夫
々過渡旋回応答性の向上に寄与する後輪の逆相（前輪と
逆方向の転舵）成分（微分成分）を決定する。 Where δ f : front wheel steering angle T: primary delay time constant of rear wheel steering system K: proportional constant τ: primary differential constant τ ': secondary differential constant S: Laplace operator The constant K determines the in-phase (steering in the same direction as the front wheel) component (proportional component) of the rear wheels that contributes to the improvement of the steady turning stability, and the differential constants τ and τ ′ contribute to the improvement of the transient turning response, respectively. A component (differential component) of the reverse phase (steering in the direction opposite to that of the front wheel) of the rear wheel is determined.
（発明が解決しようとする課題） ところで後輪操舵制御定数K,τ，τ′は夫々、例えば
第９図に示す前後輪舵角比δr/δｆが得らえるような車
速Ｖのみの関数として設定するものであり、前輪舵角に
対しては固定であったため、以下の問題を生ずる。(Problems to be Solved by the Invention) By the way, the rear wheel steering control constants K, τ, and τ ′ are, for example, only the vehicle speeds V at which the front and rear wheel steering angle ratio δ r / δ f shown in FIG. 9 is obtained. Since it is set as a function and is fixed with respect to the front wheel steering angle, the following problem occurs.
すなわち、車両の前輪舵角が大きいということは、そ
れだけ車両の回頭性を要求していることであり、それに
もかかわらずこの前輪大操舵状態で上記の後輪操舵がそ
のまま実施されるのでは、前記比例成分が後輪の同相転
舵分で車両の回頭性を抑制することとなり、運転者の要
求に逆行して操舵しずらくする。That is, the fact that the front wheel steering angle of the vehicle is large means that the turning performance of the vehicle is required accordingly. Nevertheless, if the rear wheel steering is performed as it is in this large front wheel steering state, The proportional component suppresses the turning performance of the vehicle by the in-phase turning of the rear wheels, which makes it difficult to steer against the driver's request.
特に前輪駆動車の場合、加速しながらの旋回中、駆動
される前輪のタイヤ接地円が加速にともなう前輪荷重の
減少で小さくなり、また前輪に駆動力がかかっているこ
とから旋回にともなう前輪タイヤのサイドフォースが相
対的に小さくなるため、アンダーステア傾向となること
が知られている。Especially in the case of a front-wheel drive vehicle, during turning while accelerating, the tire contact circle of the driven front wheel becomes smaller due to the decrease in front wheel load accompanying acceleration, and the front wheel tire accompanying turning due to the driving force applied to the front wheel It is known that the side force is relatively small, resulting in an understeer tendency.
しかして前記後輪操舵は、基本的に比例成分により同
相成分を大きくして後輪を同相転舵することであり、こ
の後輪同相転舵は前輪駆動車の加速旋回中における上記
アンダーステア傾向を更に助長することとなる。従っ
て、前輪大操舵状態で前輪駆動車を加速旋回させる時著
しいアンダーステアにより、この車両をはなはだ操舵し
にくくする。Thus, the rear wheel steering is basically to increase the in-phase component by a proportional component to steer the rear wheels in phase, and this rear wheel in-phase steering reduces the above-described understeer tendency during the acceleration turning of the front wheel drive vehicle. It will further encourage. Therefore, when the front wheel drive vehicle is accelerated and turned in the large front wheel steering state, the vehicle is hardly steered due to remarkable understeer.
なお、従来、特開昭２−18171号公報により、大きな
前輪舵角域では、前輪操舵角速度に応じた後輪舵角（微
分成分）を前輪操舵角の増大につれ大きくする技術が示
されている。しかしこの技術は、前輪操舵角を変化させ
ている間の過度時における車両の初期回答性を改善する
ものであり、加速旋回中の前輪駆動車に特有な、前輪操
舵角を一定にしたもとでの、上記アンダーステアに関す
る問題を、当該技術では解消することができない。Conventionally, Japanese Patent Application Laid-Open No. 2-18171 discloses a technique in which, in a large front wheel steering angle range, a rear wheel steering angle (differential component) corresponding to a front wheel steering angular velocity increases as the front wheel steering angle increases. . However, this technology is intended to improve the initial response of the vehicle in an excessive period while changing the front wheel steering angle, and to maintain a constant front wheel steering angle peculiar to a front wheel drive vehicle during acceleration turning. However, the above-described problem relating to understeer cannot be solved by the technology.
本発明は、高車速域で旋回安定性の向上を狙って与え
る後輪の同相舵角を前輪操舵角が大きい状態のもとで減
少させ、更なる大操舵角のもとで後輪舵角を逆相に転ず
ることにより、前輪駆動車の全ての前輪操舵角に亘って
前記アンダーステアに関する問題を解消することを目的
とする。The present invention reduces the in-phase steering angle of the rear wheels, which aims to improve turning stability in a high vehicle speed range, in a state where the front wheel steering angle is large, and reduces the rear wheel steering angle in a further large steering angle. Is turned to the opposite phase to solve the problem related to the understeer over all the front wheel steering angles of the front wheel drive vehicle.
（課題を解決するための手段） この目的のため第１発明は第１図に概念を示す如く、 車速が予め設定された値以上の走行時に後輪を、前輪
の操舵角に応じた比例成分で前輪と同じ方向の同相に操
舵するようにした前輪駆動車の後輪操舵装置において、 前輪操舵角が設定値以上となったのを検出する前輪大
操舵角検出手段と、 該前輪大操舵角検出手段からの検出信号に基づき、前
輪が大舵角操舵された状態では前記比例成分を、前輪操
舵角の増大につれて大きく減じる比例成分減少手段と、 前記比例成分が０になった時の前輪操舵角以上の舵角
域で該比例成分を、前輪操舵角の増大につれて後輪が大
きく前輪と逆方向の逆相に転舵されるよう極性反転させ
る比例成分極性反転手段とを設けたことを特徴とするも
のである。(Means for Solving the Problems) For this purpose, the first invention, as shown in the concept of FIG. 1, uses a proportional component corresponding to the steering angle of the front wheels when the vehicle speed is equal to or higher than a predetermined value. A front wheel large steering angle detecting means for detecting that the front wheel steering angle has become equal to or greater than a set value in a rear wheel steering device of a front wheel drive vehicle in which the steering is performed in the same direction in the same direction as the front wheel; A proportional component decreasing means for greatly reducing the proportional component when the front wheel is steered at a large steering angle based on a detection signal from the detecting means; and a front wheel steering when the proportional component becomes zero. A proportional component polarity reversing means for reversing the polarity of the proportional component in a steering angle range equal to or larger than the angle so that the rear wheel is steered in the opposite phase in the opposite direction to the front wheel as the front wheel steering angle increases. It is assumed that.
又第２発明は上記第１発明において、 前記比例成分と、後輪を前輪の操舵角の微分値に応じ
前輪とは逆方向の逆相に操舵する微分成分との和に対応
した角度で後輪を操舵することを特徴とするものであ
る。In a second aspect based on the first aspect, the rear component is rearwardly formed at an angle corresponding to a sum of the proportional component and a differential component that steers the rear wheel in the opposite phase to the front wheel in a direction opposite to that of the front wheel in accordance with the differential value of the steering angle of the front wheel. It is characterized by steering wheels.
更に第３発明は上記第２発明において、 前記前輪大操舵角検出手段からの検出信号に基づき、
前輪が大舵角操舵された状態では、前記微分成分を増加
させる微分成分増加手段を設けたことを特徴とするもの
である。In a third aspect based on the second aspect, based on a detection signal from the front wheel large steering angle detection means,
When the front wheels are steered by a large steering angle, a differential component increasing means for increasing the differential component is provided.
（作 用） 第１発明において後輪操舵装置は、前輪駆動車が設定
車速以上の高車速で走行する間、前輪操舵角に応じた比
例成分で後輪を同相方向に転舵し、これにより高車速で
の旋回安定性を向上させる。(Operation) In the first invention, the rear wheel steering device steers the rear wheels in the same phase direction with a proportional component corresponding to the front wheel steering angle while the front wheel drive vehicle runs at a high vehicle speed equal to or higher than the set vehicle speed. Improves turning stability at high vehicle speeds.
ところで、かかる後輪の同相転舵は前輪駆動車特有の
加速旋回走行中におけるアンダーステア傾向を助長す
る。By the way, the in-phase turning of the rear wheels promotes an understeer tendency during the acceleration turning operation peculiar to the front wheel drive vehicle.
しかして、前輪大操舵角検出手段が設定値以上の前輪
操舵角を検出する時、比例成分減少手段が上記の比例成
分を減少させて、これによる後輪同相舵角を減ずるた
め、また、上記比例成分が０になった時の前輪操舵角以
上の舵角域で比例成分極性反転手段が当該比例成分を、
前輪操舵角の増大につれて後輪が大きく前輪と逆方向の
逆相に転舵されるよう極性反転させるため、前輪駆動車
の上記アンダーステア傾向が助長されるといった問題
を、前輪駆動車の全ての前輪操舵角に亘って確実に改善
することができる。Thus, when the front wheel large steering angle detecting means detects the front wheel steering angle equal to or larger than the set value, the proportional component reducing means reduces the above proportional component, thereby reducing the rear wheel in-phase steering angle. In a steering angle range equal to or larger than the front wheel steering angle when the proportional component becomes 0, the proportional component polarity reversing means converts the proportional component into:
As the front wheel steering angle increases, the polarity of the rear wheel is reversed so that the rear wheel is steered in a direction opposite to that of the front wheel, so that the understeer tendency of the front wheel drive vehicle is promoted. It is possible to improve reliably over the steering angle.
又第２発明においては、後輪を上記比例成分によるだ
けでなく、これと、前輪操舵角の微分値に応じた逆相方
向微分成分との和値に対応した舵角だけ操舵するから、
第１発明の上記作用効果に加え、微分成分の付加により
前輪駆動車の過渡旋回応答性を向上させることもでき
る。In the second invention, the rear wheels are steered not only by the proportional component but also by the steering angle corresponding to the sum of the proportional component and the negative differential component corresponding to the differential value of the front wheel steering angle.
In addition to the above operation and effect of the first invention, the transient turning response of the front wheel drive vehicle can be improved by adding a differential component.
更に第３発明では、前輪大操舵角検出手段により前輪
操舵角が設定値以上であると検出される時、微分成分増
加手段が上記の微分成分を増加させるから、第２発明の
効果に加えて更に、大操舵時の過渡旋回応答性の更なる
向上を図ることができる。Further, in the third invention, when the front wheel large steering angle detecting means detects that the front wheel steering angle is equal to or larger than the set value, the differential component increasing means increases the above differential component. Further, the transient turning response at the time of large steering can be further improved.
（実施例） 以下、本発明の実施例を図面に基づき詳細に説明す
る。Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
第２図は本発明後輪操舵装置のシステムを示し、図中
1L,1Rは夫々駆動輪でもある左右前輪、2L,2Rは夫々左右
後輪である。前輪1L,1Rを夫々ステアリングホイール３
によりステアリングギヤ４を介して転舵可能とし、トラ
ンスバースリンク5L,5R及びアッパアーム6L,6Rを含むリ
ヤサスペンション装置により車体のリヤサスペンション
メンバ７に懸架された後輪2L,2Rも転舵可能とするた
め、後輪のナックルアーム8L,8R間をアクチュエータ９
及びその両端におけるサイドロッド10L,10Rにより相互
に連結する。FIG. 2 shows a system of the rear wheel steering device according to the present invention.
Reference numerals 1L and 1R denote left and right front wheels which are also drive wheels, and reference numerals 2L and 2R denote left and right rear wheels, respectively. Steering wheel 3 for front wheels 1L and 1R respectively
, The rear wheels 2L, 2R suspended on the rear suspension member 7 of the vehicle body by the rear suspension device including the transverse links 5L, 5R and the upper arms 6L, 6R can also be steered. Therefore, an actuator 9 is installed between the rear wheel knuckle arms 8L and 8R.
And are connected to each other by side rods 10L and 10R at both ends thereof.
アクチュエータ９はスプリングセンタ式復動液圧シリ
ンダとし、その２室を夫々管路11L,11Rにより電磁比例
式圧力制御弁12に接続する。この制御弁12には更にポン
プ13及びリザーバタンク14を含む液圧源の液圧管路15及
びドレン管路16を夫々接続する。制御弁12はスプリング
センタ式３位置弁とし、両ソレノイド12L,12RのOFF時管
路11L,11Rを無圧状態にし、ソレノイド12LのON時通電量
iLに比例した圧力を管路11Lに供給し、ソレノイド12Rの
ON時通電量iRに比例した圧力を管路11Rに供給するもの
とする。管路11Lからの圧力はその値に応じた舵角だけ
後輪をアクチュエータ９により左転舵し、管路11Rから
の圧力はその値に応じた舵角だけ後輪をアクチュエータ
９により右転舵する。The actuator 9 is a spring-centered backward hydraulic cylinder, and its two chambers are connected to the electromagnetic proportional pressure control valve 12 by pipe lines 11L and 11R, respectively. The control valve 12 is further connected to a hydraulic line 15 and a drain line 16 of a hydraulic source including a pump 13 and a reservoir tank 14, respectively. The control valve 12 is a spring-centered three-position valve. When both solenoids 12L and 12R are OFF, the lines 11L and 11R are in a non-pressure state, and when the solenoid 12L is ON, the amount of electricity is ON.
The pressure proportional to i L supplied to the conduit 11L, the solenoid 12R
The pressure proportional to the energization amount i R ON and supplies the pipe 11R. The pressure from the pipe 11L turns the rear wheel to the left by the actuator 9 by the steering angle corresponding to the value, and the pressure from the pipe 11R turns the rear wheel to the right by the actuator 9 by the steering angle according to the value. I do.
ソレノイド12L,12RのON,OFF及び通電量はコントロー
ラ17により電子制御し、このコントローラ17は第３図に
示す如くデジタル演算回路17aと、デジタル入力検出回
路17bと、記憶回路17cと、D/A変換器17dと、駆動回路17
eとで構成する。コントローラ17には、ステアリングホ
イール３の操舵角θを検出する操舵角センサ18からの信
号及び車速Ｖを検出する車速センサ19からの信号を夫
々、デジタル入力検出回路17bを経て入力する。コント
ローラ17のデジタル演算回路17aはこれら入力情報及び
記憶回路17cの格納情報から第４図の制御プログラムを
実行して後輪を操舵する。The ON / OFF and energizing amounts of the solenoids 12L and 12R are electronically controlled by a controller 17, and the controller 17 includes a digital operation circuit 17a, a digital input detection circuit 17b, a storage circuit 17c, and a D / A as shown in FIG. Converter 17d and drive circuit 17
and e. A signal from a steering angle sensor 18 for detecting the steering angle θ of the steering wheel 3 and a signal from a vehicle speed sensor 19 for detecting the vehicle speed V are input to the controller 17 via a digital input detection circuit 17b. The digital operation circuit 17a of the controller 17 executes the control program shown in FIG. 4 from the input information and the information stored in the storage circuit 17c to steer the rear wheels.
第４図中ステップ31では、操舵角θ及び車速Ｖを読込
み、次のステップ32で前輪舵角δｆをステアリングホイ
ール操舵角θ及びステアリングギヤ比Ｎから の演算により求める。そしてステップ33では車速Ｖから
例えば第９図に例示した比例定数Ｋ及び微分定数τ，
τ′を演算又はルックアップする。比例定数Ｋは後輪舵
角の比例成分を決定し、本例ではこれを常時正とする。
従って前記（１）式に照らして明らかな如く前輪舵角δ
ｆに応じた比例成分は同相後輪舵角量となる。又微分定
数τ，τ′は後輪舵角の微分成分を決定し、本例ではこ
れを負の値とする。従って前記（１）式に照らして明ら
かな如く前輪舵角δｆの変化速度及び変化加速度に応じ
た微分成分は逆相後輪舵角量なる。又ステップ34では、
操舵角θから第５図に対応したテーブルデータを基に重
み付け係数f1をルックアップする。この重み付け係数f1
は次のステップ35における式から明らかなように、比例
定数Ｋに応じた比例成分を修正するもので、第５図中θ
０で示す設定値以上の操舵角域で、つまり前輪大操舵状
態において操舵角θが大きくなるにつれ１から漸減さ
せ、θ≧θ１の領域でf1を負とするようにする。従っ
て、ステップ34が本発明における前輪大操舵角検出手段
に相当し、ステップ34,35における重み付け係数f1が本
発明における比例成分減少手段に相当する。In Figure 4 in step 31, the steering angle θ and the vehicle speed V read, a front wheel steering angle [delta] f in the next step 32 from the steering wheel steering angle θ and the steering gear ratio N Is calculated by the following calculation. Then, in step 33, from the vehicle speed V, for example, a proportional constant K and a differential constant τ, as illustrated in FIG.
τ ′ is calculated or looked up. The proportional constant K determines a proportional component of the rear wheel steering angle, and in this example, this is always positive.
Therefore, as apparent from the above equation (1), the front wheel steering angle δ
The proportional component corresponding to f is the in-phase rear wheel steering angle amount. The differential constants τ and τ ′ determine the differential component of the rear wheel steering angle, which is a negative value in this example. Thus the (1) differential component after reverse phase wheel steering angle amount corresponding to the change velocity and change acceleration apparent as the front wheel steering angle [delta] f the light of expressions. In step 34,
To look up the weighting factor f 1 based on the table data corresponding to FIG. 5 from the steering angle theta. This weighting factor f 1
Is to correct the proportional component according to the proportionality constant K, as is clear from the equation in the next step 35. In FIG.
In more than the set value of the steering angle range indicated by 0, that is, in front large steering state is gradually decreased from 1 as the steering angle theta is increased, so as to negative f 1 at theta ≧ theta 1 region. Thus, step 34 corresponds to the front wheel larger steering angle detecting means in the present invention, the weighting factor f 1 at step 34 and 35 corresponds to the proportional component reducing means in the present invention.
ちなみに第５図の重み付け係数f1はθ≧θ０の前輪大
操舵域で操舵角θの関数 として表わされる。Incidentally, the weighting coefficient f 1 in FIG. 5 is a function of the steering angle θ in the large front wheel steering region where θ ≧ θ 0. Is represented as
ステップ35では、前記（１）式に重み付け係数f1を付
加した の式を演算することにより後輪舵角δｒを求める。次に
ステップ36で、この演算舵角δｒに応じた電流iL又はiR
を第２図の弁12へ出力して後輪を演算通りに操舵する。In step 35, by adding a weighting factor f 1 in the expression (1) Determining the rear wheel steering angle [delta] r by computing equation. In step 36, the current i L or i R corresponding to the operation steering angle [delta] r
Is output to the valve 12 in FIG. 2 to steer the rear wheels as calculated.
ところで、比例定数Ｋにより決まる後輪舵角の比例成
分δrk＝δｆ・Ｋに重み付け係数f1を乗じ、この係数f1
を第５図の如くに定めるから、操舵角θを設定値θ０以
上となす前輪大操舵状態で、第６図中実線により示す通
り操舵角θを大きくするほど後輪舵角の比例成分δrkが
同相舵角量を破線で示す従来のものより小さくされ、θ
＞θ１では遂に比例成分δrkが逆相舵角量に転ずる。ち
なみに、第６図の実線で示す比例成分δrkは で表わされる。By the way, the proportional component δ rk = δ f · K of the rear wheel steering angle determined by the proportional constant K is multiplied by a weighting coefficient f 1 , and this coefficient f 1
As shown in FIG. 5, in the large front wheel steering state in which the steering angle θ is equal to or larger than the set value θ 0 , the proportional component δ of the rear wheel steering angle increases as the steering angle θ increases as shown by the solid line in FIG. rk is smaller than the conventional one shown by the broken line for the in-phase rudder angle, and θ
> In the theta 1 finally proportional component [delta] rk is starts to reverse phase steering angle amount. Incidentally, the proportional component δ rk shown by the solid line in FIG. Is represented by
よってθ＞θ０の前輪大操舵状態では、前輪舵角に体
する比例成分δrkの同相舵角量が前輪舵角の増大につれ
小さくなり、比例成分δrkが更なる前輪舵角の増大時遂
に逆相に転ずることから、車両の回頭性を要求して前輪
操舵量を大きくするにつれ、前記（２）式により与えら
れる後輪舵角δｒが同相舵角を小さくされ、遂には逆相
舵角にされることとなる。このため前輪大操舵状態で後
輪操舵が車両の回頭性を要求に反して犠牲にし、これに
より車両が操縦しずらくなるのを防止することができ
る。Therefore, in the large front wheel steering state where θ> θ 0 , the in-phase steering angle amount of the proportional component δ rk representing the front wheel steering angle decreases as the front wheel steering angle increases, and the proportional component δ rk decreases when the front wheel steering angle further increases. since the last turn in the opposite phase, as to increase the front wheel steering amount requesting turning property of the vehicle, the (2) wheel steering angle [delta] r after given by formula is reduced phase steering angle, it is finally reversed phase The steering angle is set. Therefore, it is possible to prevent the rear wheel steering from sacrificing the turning performance of the vehicle against the request in the large front wheel steering state, thereby making it difficult for the vehicle to steer.
特に前輪駆動車の加速旋回中は前記したようにアンダ
ーステア傾向となり、これが比例成分δrkにより助長さ
れて、前輪駆動車をはなはだ操縦しにくくするが、比例
成分を上記のように大操舵角域で操舵角の上昇につれ減
少させることにより、この操縦しにくさを緩和すること
ができる。Especially during the acceleration turning of the front wheel drive vehicle, the vehicle tends to understeer as described above, and this is promoted by the proportional component δ rk , which makes it difficult to steer the front wheel drive vehicle very much, but the proportional component in the large steering angle range as described above. This difficulty in maneuvering can be reduced by decreasing the steering angle as the steering angle increases.
しかして、この問題を生じないθ＜θ０では、f1＝１
であるから、後輪舵角δｒは比例成分を修正されること
なく、前記（１）式によると同じ値にされ、所定通りに
旋回安定性の向上を達成することができる。Therefore, when θ <θ 0 which does not cause this problem, f 1 = 1
Since it is, the rear wheel steering angle [delta] r is without being corrected proportional component, is the same value according to the equation (1), it is possible to achieve an improvement of cornering stability in a predetermined manner.
なお、比例成分δrkを前記の目的で修正するに当り、
第６図の如き放物線形状に修正する場合、設計自由度が
低く、車両諸元や車両の性格付けによっては、狙い通り
の作用効果を達成し得ないことが考えられる。従って、
重み付け係数f1は第５図に示す如き直線特性にする代り
に曲線にしてもよく、この場合曲線の与え方次第で後輪
舵角の比例成分δrkは第７図中実線（イ）、１点鎖線
（ロ）、２点鎖線（ハ）で示すように修正の仕方を要求
に合せて自由に選択することができる。In correcting the proportional component δ rk for the above purpose,
When the parabolic shape is modified as shown in FIG. 6, the degree of freedom in design is low, and it is conceivable that the intended effect cannot be achieved depending on the vehicle specifications and the characteristics of the vehicle. Therefore,
Weighting factor f 1 may be a curve instead of a straight line characteristic as shown in FIG. 5, the proportional component [delta] rk of the rear wheel steering angle depending on how applied in this case curve in FIG. 7 the solid line (b), As shown by the one-dot chain line (b) and the two-dot chain line (c), the method of correction can be freely selected according to the requirements.
なお上述の例では、重み付け係数f1により比例成分δ
rkを補正して、前輪大操舵状態で後輪操舵が前輪駆動車
を操縦しずらくしたり、そのアンダーステア傾向が助長
されるのを防止する構成としたが、これと同時に微分定
数τ，τ′で決まる逆相成分を付加したり増大させて、
過渡旋回応答性をも向上させることができる。Note in the above example, the weighting factor f 1 proportional component δ
rk is corrected to prevent the rear wheel steering from making it difficult to steer the front wheel drive vehicle in the large front wheel steering state, and to prevent the understeer tendency from being promoted, but at the same time, the differential constants τ, τ ′ By adding or increasing the negative phase component determined by
Transient turning response can also be improved.
これらの事実に基づき第８図は第４図中のステップ3
4,35をステップ74,75に置換したものである。Based on these facts, FIG. 8 shows step 3 in FIG.
Steps 4 and 35 are replaced with steps 74 and 75.
第８図の例は、重み付け係数f1,f2,f3を全て用いるも
ので、ステップ74において操舵角θから第５図に対応す
るテーブルデータを基に重み付け係数f1,f2,f3をルック
アップする。ここでこれら係数f2,f3は夫々θ＞θ０域
で操舵角θの増大につれ１より漸増するものとする。従
って本例では、ステップ74が本発明における前輪大操舵
角検出手段に相当する。次のステップ75では、前記
（１）式に重み付け係数f1,f2,f3を付加した の式を演算することにより後輪舵角δｒを求める。この
場合も、θ＞θ０域で後輪舵角の比例成分が、前輪駆動
車の回頭性を向上してアンダーステアを緩和するよう減
少される。更に本例では、微分成分の付加により車両の
旋回応答性を向上させ得るだけでなく、該微分成分に重
み付けを行ったことで、θ＞θ０とする大操舵時の過渡
応答性を一層向上させることができる。従って、ステッ
プ74,75における重み付け係数f2,f3が本発明における微
分成分増加手段に相当する。The example of Figure 8 is intended to use all the weighting coefficients f 1, f 2, f 3, the weighting factor f 1 based on table data corresponding to FIG. 5 from the steering angle θ in step 74, f 2, f Look up 3 Here, it is assumed that these coefficients f 2 and f 3 gradually increase from 1 as the steering angle θ increases in the range of θ> θ 0 . Therefore, in this example, step 74 corresponds to the front wheel large steering angle detecting means of the present invention. In the next step 75, weighting coefficients f 1 , f 2 and f 3 are added to the above equation (1). Determining the rear wheel steering angle [delta] r by computing equation. Again, the proportional component of the rear wheel steering angle theta> theta 0 area is reduced so as to mitigate the understeer to improve the front-wheel drive vehicle turning property. Further in this embodiment, not only can improve the turning responsiveness of a vehicle by the addition of the differential component, by performing the weighted fine fraction component, theta> theta 0 to further improve the transient response of large steering when Can be done. Therefore, the weighting coefficients f 2 and f 3 in steps 74 and 75 correspond to the differential component increasing means in the present invention.
（発明の効果） かくして本発明の後輪操舵装置は、高車速での旋回安
定性を目的とし、前輪操舵角に応じた比例成分で後輪を
同相に転舵するに際し、 前輪大操舵角域では上記の比例成分を、前輪操舵角の
増大につれ大きく減少させて、これによる後輪同相舵角
を減ずる構成とし、 更に、上記比例成分が０になった時の前輪操舵角以上
の舵角域で該比例成分を、前輪操舵角の増大につれて後
輪が大きく逆相転舵されるよう極性反転させる構成とし
たら、 前輪駆動車の前記アンダーステア傾向が助長されると
いった問題を、前輪駆動車の全ての前輪操舵角域におい
て確実に改善することができる。(Effect of the Invention) Thus, the rear wheel steering apparatus of the present invention aims at turning stability at a high vehicle speed, and when turning the rear wheels in phase with a proportional component corresponding to the front wheel steering angle, the front wheel large steering angle range The above proportional component is greatly reduced as the front wheel steering angle is increased, thereby reducing the rear wheel in-phase steering angle. Further, a steering angle range equal to or larger than the front wheel steering angle when the proportional component becomes 0 is obtained. If the proportional component is configured to reverse the polarity so that the rear wheels are largely reversed in phase with an increase in the front wheel steering angle, the problem that the understeer tendency of the front wheel drive vehicle is promoted is reduced in all front wheel drive vehicles. In the front wheel steering angle range.
又第２発明においては、後輪を上記比例成分によるだ
けでなく、これと、前輪操舵角の微分値に応じた逆相方
向微分成分との和値に対応した舵角だけ操舵するから、 第１発明の上記作用効果に加え、微分成分の付加によ
り前輪駆動車の過渡旋回応答性を向上させることもでき
る。In the second invention, the rear wheel is steered not only by the proportional component but also by the steering angle corresponding to the sum of the proportional component and the negative differential component in accordance with the differential value of the front wheel steering angle. In addition to the above operation and effect of the first invention, the transient turning response of the front wheel drive vehicle can be improved by adding a differential component.
更に第３発明では、前輪大操舵角域で、上記の微分成
分を増加させる構成としたから、 第２発明の効果に加えて更に、大操舵時の過渡旋回応
答性の更なる向上を図ることができる。Further, in the third invention, the above-described differential component is increased in the large front wheel steering angle range. In addition to the effect of the second invention, the transient turning response during large steering is further improved. Can be.
第１図は本発明後輪操舵装置を示す概念図、 第２図は本発明装置の一実施例を示す４輪操舵車両の操
舵システム図、 第３図は同システムにおけるコントローラのブロック線
図、 第４図は同コントローラの制御プログラムを示すフロー
チャート、 第５図は後輪操舵の比例成分及び微分成分に関する重み
付け係数の変化特性図、 第６図は同例における後輪舵角の比例成分補正具合を示
す特性図、 第７図は比例成分補正具合の他の３例を示す特性図、 第８図は本発明の他の例を示す第４図と同様なフローチ
ャート、 第９図は一般的な後輪操舵制御定数の変化特性図であ
る。 1L,1R……前輪 2L,2R……後輪 ３……ステアリングホイール ４……ステアリングギヤ 5L,5R……トランスバースリンク 6L,6R……アッパアーム ７……リヤサスペンションメンバ ９……アクチュエータ 12……電磁比例式圧力制御弁 17……コントローラ 18……操舵角センサ 19……車速センサ1 is a conceptual diagram showing a rear wheel steering device of the present invention, FIG. 2 is a steering system diagram of a four-wheel steering vehicle showing one embodiment of the present invention device, FIG. 3 is a block diagram of a controller in the system, FIG. 4 is a flowchart showing a control program of the controller. FIG. 5 is a diagram showing a change characteristic of a weighting coefficient relating to a proportional component and a differential component of rear wheel steering. FIG. FIG. 7 is a characteristic diagram showing three other examples of the proportional component correction condition, FIG. 8 is a flowchart similar to FIG. 4, showing another example of the present invention, and FIG. FIG. 7 is a diagram illustrating a change characteristic of a rear wheel steering control constant. 1L, 1R Front wheel 2L, 2R Rear wheel 3 Steering wheel 4 Steering gear 5L, 5R Transverse link 6L, 6R Upper arm 7 Rear suspension member 9 Actuator 12 Electromagnetic proportional pressure control valve 17 Controller 18 Steering angle sensor 19 Vehicle speed sensor
Claims (3)
輪を、前輪の操舵角に応じた比例成分で前輪と同じ方向
の同相に操舵するようにした前輪駆動車の後輪操舵装置
において、 前輪操舵角が設定値以上となったのを検出する前輪大操
舵角検出手段と、 該前輪大操舵角検出手段からの検出信号に基づき、前輪
が大舵角操舵された状態では前記比例成分を、前輪操舵
角の増大につれて大きく減じる比例成分減少手段と、 前記比例成分が０になった時の前輪操舵角以上の舵角域
で該比例成分を、前輪操舵角の増大につれて後輪が大き
く前輪と逆方向の逆相に転舵されるよう極性反転させる
比例成分極性反転手段とを設けたことを特徴とする前輪
駆動車の後輪操舵装置。1. A rear-wheel steering system for a front-wheel drive vehicle in which a rear wheel is steered in the same phase in the same direction as a front wheel with a proportional component corresponding to the steering angle of the front wheel when the vehicle speed is equal to or higher than a predetermined value. In the above, the front wheel large steering angle detecting means for detecting that the front wheel steering angle has become greater than or equal to a set value, and the proportional control is performed in a state where the front wheels are steered by a large steering angle based on a detection signal from the front wheel large steering angle detecting means. A proportional component decreasing means for greatly reducing the component as the front wheel steering angle increases; and a rear wheel as the front wheel steering angle increases, the proportional component in a steering angle range equal to or larger than the front wheel steering angle when the proportional component becomes 0. A rear wheel steering device for a front wheel drive vehicle, comprising: a proportional component polarity reversing means for reversing the polarity so that the front wheels are largely turned in the opposite phase to the opposite direction.
分値に応じ前輪とは逆方向の逆相に操舵する微分成分と
の和に対応した角度で後輪を操舵することを特徴とする
請求項１記載の前輪駆動車の後輪操舵装置。The steering of the rear wheel at an angle corresponding to the sum of the proportional component and a differential component for steering the rear wheel in the opposite phase to the front wheel in a direction opposite to that of the front wheel according to the differential value of the steering angle of the front wheel. The rear wheel steering device according to claim 1, wherein the rear wheel steering device is a front wheel drive vehicle.
に基づき、前輪が大舵角操舵された状態では、前記微分
成分を増加させる微分成分増加手段を設けたことを特徴
とする請求項２記載の前輪駆動車の後輪操舵装置。3. A differential component increasing means for increasing the differential component when a front wheel is steered by a large steering angle based on a detection signal from the front wheel large steering angle detecting means. 3. The rear wheel steering device according to claim 2, wherein
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/676,120 US5186273A (en) | 1990-03-28 | 1991-03-27 | Rear wheel steering system for automotive vehicle |
| GB9106555A GB2243127B (en) | 1990-03-28 | 1991-03-27 | Rear wheel steering system for automotive vehicle |
| DE4110107A DE4110107C2 (en) | 1990-03-28 | 1991-03-27 | Rear wheel steering system for a motor vehicle |
| FR9103793A FR2660275A1 (en) | 1990-03-28 | 1991-03-28 | REAR WHEEL ROTATION SYSTEM FOR A MOTOR VEHICLE. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12450389 | 1989-05-19 | ||
| JP1-124503 | 1989-05-19 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0374283A JPH0374283A (en) | 1991-03-28 |
| JP2591236B2 true JP2591236B2 (en) | 1997-03-19 |
Family
ID=14887105
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2076699A Expired - Lifetime JP2591236B2 (en) | 1989-05-19 | 1990-03-28 | Rear wheel steering system for front wheel drive vehicles |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2591236B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60166561A (en) * | 1984-02-08 | 1985-08-29 | Mazda Motor Corp | Four wheel steering device for vehicle |
| JPS62146783A (en) * | 1985-12-23 | 1987-06-30 | Toyota Motor Corp | Control device for front and rear wheel steered car |
-
1990
- 1990-03-28 JP JP2076699A patent/JP2591236B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0374283A (en) | 1991-03-28 |
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