JPS6280174A - Four wheel steering device - Google Patents
Four wheel steering deviceInfo
- Publication number
- JPS6280174A JPS6280174A JP22151685A JP22151685A JPS6280174A JP S6280174 A JPS6280174 A JP S6280174A JP 22151685 A JP22151685 A JP 22151685A JP 22151685 A JP22151685 A JP 22151685A JP S6280174 A JPS6280174 A JP S6280174A
- Authority
- JP
- Japan
- Prior art keywords
- steering
- mode
- steering ratio
- vehicle speed
- vehicle
- 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.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D7/00—Steering linkage; Stub axles or their mountings
- B62D7/06—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
- B62D7/14—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
- B62D7/15—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels
- B62D7/1509—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels with different steering modes, e.g. crab-steering, or steering specially adapted for reversing of the vehicle
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D7/00—Steering linkage; Stub axles or their mountings
- B62D7/06—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
- B62D7/14—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
- B62D7/15—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels
- B62D7/1581—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels characterised by comprising an electrical interconnecting system between the steering control means of the different axles
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
Abstract
Description
四輪操舵装置を備えた自動車において、最高のドライバ
ビリティを実現するには、遠心力の影響が少ない低速時
と、遠心力を考慮する必要がある高速時とのいずれであ
っても車両のすべり角を0に近付けるために、前輪の転
舵角に対する後輪の転舵角の比を表わす転舵比kを車速
に応じて変化させる必要があり、車速と転舵比との関係
は、概ね第2図に示す関係であることが好ましいことが
知られている。ここで転舵比が正の領域は前輪の転舵方
向と後輪の転舵方向が互いに逆方向の、いわゆる逆位相
であることを示し、転舵比が負の領域は、前輪の転舵方
向と後輪の転舵方向が互いに同位相の、いわゆる同位相
であることを示す。
低速時には、後輪が逆位相に転舵されるので、車体の旋
回中心が車体中心を通る線上に近づき、しまたがって車
体のすべり角がOに近付くとともに、旋回半径が前輪の
み転舵する場合に比べて小さくなる。一方、高速時には
、遠心力の影響により前輪と路面との間にすべり角が生
じ、これにより旋回中心が前方に移行する傾向が生じる
が、この傾向を後輪を前輪と同位相に転舵することによ
り相殺し、旋回中心を車体中心を通る車幅方向線上に近
付けることができる。低速時および高速時のいずれであ
っても車体旋回中心が車体中心を通る車幅方向線上に来
ることは、車体のすべり角がなくなることを意味し、こ
れにより旋回時でのドライバビリティが著しく向上する
。
ところで、このような四輪操舵装置を備える車両におい
ては、第2図に示すような車速と転舵比との関係で後輪
を自動的に制御するAUTO・モードと、低速時である
ことを条件として後輪を前輪に対して同位相に同角度(
すなわち転舵比=−1)転舵する同位相モードとを選択
するようにすることがある。この同位相モードは、たと
えば車速か5km/h以下であることを条件に、車体を
平行に幅寄せして縦列駐車する場合にとくに選択される
べきモードであるから、車速か所定値を超えたとき自動
的にAUTO・モードに復帰させる必要がある。In order to achieve the best drivability in a car equipped with a four-wheel steering system, it is important to avoid vehicle slippage at both low speeds, where the influence of centrifugal force is small, and at high speeds, where centrifugal force must be taken into account. In order to bring the angle close to 0, it is necessary to change the steering ratio k, which represents the ratio of the rear wheel steering angle to the front wheel steering angle, according to the vehicle speed, and the relationship between the vehicle speed and the steering ratio is roughly as follows. It is known that the relationship shown in FIG. 2 is preferable. Here, the region where the steering ratio is positive indicates that the front wheel steering direction and the rear wheel steering direction are opposite to each other, so-called antiphase, and the region where the steering ratio is negative indicates that the front wheel steering direction and the rear wheel steering direction are opposite to each other. This indicates that the direction and the steering direction of the rear wheels are in the same phase with each other, so-called in-phase. At low speeds, the rear wheels are steered in the opposite phase, so the turning center of the vehicle approaches the line passing through the center of the vehicle, the slip angle of the vehicle approaches O, and the turning radius is such that only the front wheels are steered. becomes smaller compared to . On the other hand, at high speeds, a slip angle occurs between the front wheels and the road surface due to the influence of centrifugal force, which tends to shift the turning center forward, but this tendency can be avoided by steering the rear wheels in the same phase as the front wheels. By doing so, the turning center can be brought closer to the vehicle width direction line passing through the center of the vehicle body. Regardless of whether the vehicle is running at low or high speeds, the fact that the center of rotation of the vehicle is on the line passing through the center of the vehicle in the vehicle width direction means that there is no slip angle of the vehicle, which significantly improves drivability when turning. do. By the way, in a vehicle equipped with such a four-wheel steering system, there is an AUTO mode that automatically controls the rear wheels depending on the relationship between vehicle speed and steering ratio, as shown in Figure 2, and an AUTO mode that automatically controls the rear wheels at low speeds. The conditions are that the rear wheels are in the same phase and at the same angle as the front wheels (
In other words, the same phase mode for steering (steering ratio=-1) may be selected. This in-phase mode is a mode that should be selected especially when parallel parking with the vehicle body parallel to each other, provided that the vehicle speed is 5 km/h or less, so if the vehicle speed exceeds a predetermined value It is necessary to automatically return to AUTO mode.
ところで、単に同位相モードがAUTO・モードに復帰
されるようにするだけでは、第6図に示すように、AU
TO・モードにおける低速領域での転舵比kが逆位相、
すなわち1に近くなっていることがら、所定車速を超え
た時点で運転者の操舵感覚と無関係に後輪が急激に左か
ら右へ、または右から左へと転舵されて車両の進行方向
が変化するという状況が現出する場合があり、危険であ
る。
この発明は、同位相モードが自動的にAUTO・モード
に切換わる場合における上記の問題を解消することをそ
の課題とする。By the way, simply returning the in-phase mode to the AUTO mode will result in the AU
The steering ratio k in the low speed region in TO mode is in opposite phase,
In other words, since the value is close to 1, when the vehicle speed exceeds a predetermined speed, the rear wheels are suddenly steered from left to right or from right to left, regardless of the driver's steering sense, and the direction of travel of the vehicle is changed. Changing situations may emerge and are dangerous. An object of the present invention is to solve the above-mentioned problem when the in-phase mode is automatically switched to the AUTO mode.
上記の問題を解決するため、この発明の四輪操舵装置は
、次のように構成されている。
すなわち、この発明の四輪操舵装置は、ステアリングシ
ャフトの回転に応じて前輪を転舵される前輪転舵機構と
、
制御手段によって制御され、かつ後輪を各転舵比データ
にしたがって転舵しうる後輪転舵機構と、AUTO・モ
ードから同位相モードに切換える同位相スイッチと、
AUTO・モード時に選択されて、後輪の前輪に対する
転舵比が車速に応じて最適となるように設定された転舵
比データを制御手段に送出する、AUTO・モード用転
舵比データ送出手段と、
同位相スイッチがオンされ、かつ車速か所定以下である
ときに選択されて、同位相としての転舵比データを制御
手段に送出する、同位相モード用転舵比データ送出手段
と、
同位相スイッチがオンされ、かつ車速が所定以上である
ときに選択されて、転舵比を同位相状態からなめらかに
Oに遷移させる、遷移時用転舵比データ送出手段と、
上記遷移時用転舵比データにしたがって後輪舵角が中立
位置に復帰後、前輪舵角がO復帰したときAUTO・モ
ードを選択するAUTO・モード復帰手段とを備えてい
る。In order to solve the above problem, the four-wheel steering system of the present invention is configured as follows. That is, the four-wheel steering device of the present invention includes a front wheel steering mechanism that steers the front wheels according to the rotation of a steering shaft, and a front wheel steering mechanism that is controlled by a control means and that steers the rear wheels according to each steering ratio data. The rear wheel steering mechanism is equipped with an in-phase switch that switches from AUTO mode to in-phase mode, and when in AUTO mode, the steering ratio of the rear wheels to the front wheels is set to be optimal depending on the vehicle speed. A steering ratio data sending means for AUTO/mode that sends steering ratio data to a control means, and a steering ratio that is selected when the same phase switch is turned on and the vehicle speed is below a predetermined value and is set as the same phase. In-phase mode steering ratio data sending means that sends data to the control means; selected when the in-phase switch is turned on and the vehicle speed is above a predetermined value, and smoothly changes the steering ratio from the in-phase state; A means for transmitting steering ratio data for transition to make the transition to O, and selecting an AUTO mode when the front wheel steering angle returns to O after the rear wheel steering angle returns to the neutral position according to the above steering ratio data for transition. AUTO/mode return means is provided.
同位相スイッチがオンされない限り、四輪操舵装置はA
UTO・モードにあり、後輪は、前輪舵角および車速に
応じてAUTO・モード用転舵比データから演算される
最適な転舵角に自動制御される。
車速か所定以下であるときに同位相スイッチがオンされ
ると、同位相モード用転舵比データ送出手段が制御手段
に同位相モード用転舵比データを送出し、これにしたが
って後輪は、前輪の転舵方向と同方向に所定量転舵され
る。
そして同位相モードが選択された状態で車両が所定車速
を超えると、遷移時用転舵比データ送出手段が制御手段
にデータを送出し、これにしたがい後輪は、滑らかな動
きで転舵比0となるように、すなわち舵角が中立位置と
なるように転舵される。
そして次に、前輪が中立位置に戻った時点で、四輪操舵
装置は再びAUTO・モードに復帰し、それ以降におい
て後輪は、AUTO・モード用転舵比データにしたがい
、車速および前輪転舵角に応じた最適な転舵角に自動制
御される。Unless the in-phase switch is turned on, the four-wheel steering system will
The vehicle is in the UTO mode, and the rear wheels are automatically controlled to the optimum steering angle calculated from the AUTO mode steering ratio data according to the front wheel steering angle and vehicle speed. When the same-phase switch is turned on when the vehicle speed is below a predetermined value, the same-phase mode steering ratio data sending means sends the same-phase mode steering ratio data to the control means, and the rear wheels accordingly The vehicle is steered by a predetermined amount in the same direction as the front wheels. When the vehicle exceeds a predetermined vehicle speed with the same phase mode selected, the transition steering ratio data transmission means sends data to the control means, and according to this, the rear wheels smoothly move to adjust the steering ratio. 0, that is, the steering angle is turned to the neutral position. Next, when the front wheels return to the neutral position, the four-wheel steering system returns to AUTO mode, and from then on, the rear wheels adjust the vehicle speed and front wheel steering according to the steering ratio data for AUTO mode. The steering angle is automatically controlled to be optimal depending on the angle.
以上の結果、本発明の四輪操舵装置では、同位相モード
で前輪が転舵された状態で車速か所定車速を超えた場合
、まず、後輪のみが滑らかな動きで中立位置に戻され、
そして車体が直進状態となってはじめてAUTO・モー
ドに復帰することになる。
したがって、たとえば同位相状態で所定車速を超えた場
合に急激にAUTO・モードに復帰させる場合のように
、後輪が前輪に対して同位相状態がら逆位相状態に急激
に方向転換することはなく、少なくとも前輪を直進状態
に戻すまでに、車体が運転者の意図する方向と逆方向に
旋回するという違和感はなくなる。As a result of the above, in the four-wheel steering system of the present invention, when the vehicle speed exceeds a predetermined vehicle speed with the front wheels being steered in the same phase mode, only the rear wheels are returned to the neutral position with smooth movement,
The vehicle returns to AUTO mode only when the vehicle is in a straight-ahead state. Therefore, the rear wheels will not suddenly change direction from the same phase state to the opposite phase state relative to the front wheels, such as when suddenly returning to AUTO mode when the vehicle speed exceeds a predetermined speed while in the same phase state. At least by the time the front wheels return to the straight-ahead state, the driver no longer feels the discomfort of the vehicle body turning in the opposite direction to the direction intended by the driver.
以下、本発明の実施例を図面を参照して具体的に説明す
る。
第1図は、本発明の四輪操舵装置の一例の全体構成図で
ある。ここで前輪転舵機構1は、従来公知のものが使用
される。すなわち、ランク・ビニオン式の転舵機構の場
合、ステアリングホイール2とともに軸転するステアリ
ングシャフト3の回転は、ギヤボックス4でたとえばラ
ック杆5の車幅方向の往復動に変換され、さらにこのラ
ック杆5の往復動は、両端のタイロッド6.6を介して
ナックルアーム7.7の軸8.8を中心とした回動に変
換され、このナックルアーム7.7の回動により、前輪
9.9は上記軸8.8を中心として転舵されるようにな
っている。
一方、本例における後輪転舵機構10は、マイクロコン
ピュータで構成される制御手段11によって制御される
ステッピングモータ12と、このステッピングモータ1
2の回転出力が減速装置13を介して入力される公知の
パワーステアリング装置14によって構成される。マイ
クロコンピュータ11には、前輪舵角センサ15、車速
センサ16および同位相スイッチ17からの信号が入力
され、かつ上記ステッピングモータへの制御線が延びる
でいる。
上記パワーステアリング装置14は、公知のラック゛ビ
ニオン式のパワーステアリング装置を使用することがで
きる。すなわち、ギヤボックス18の入力部に付設され
たコントロールバルブ部19は、ポンプ20からの圧油
を、入力軸21の回転方向に応じて、ギヤボックス18
内に形成される複動パワーシリンダ部22に圧油を送り
、このパワーシリンダ部22がラック杆23の動きを支
援する。ラック杆23の動きは、その両端に連結された
タイロッド24.24によってナックルアーム25,2
5に伝達されてこのナックルアーム25.25を軸26
.26を中心として回転させ、これにより後輪27.2
7は上記軸26.26を中心として所定方向に転舵され
る。
上記マイクロコンピュータ内には、AUTO・モード時
に選択されて車速に応じた最適な転舵比情報を送出する
AUTO・モード用転舵比データ送出手段28が形成さ
れる。このAUTO・モード用転舵比データとしては、
たとえば、第2図に示すような車速■と転舵比にの関係
が選択され、これがデータテーブルとしてROMあるい
は不揮発性RAMなどに格納される。
また、上記マイクロコンピュータ内には、同位相スイッ
チ17がオンされ、かつ車速か所定以下であるときに選
択されて、同位相としての転舵比データを送出する、同
位相モード用転舵比データ送出手段29が形成される。
同位相モード用転舵比データとしては、通常転舵比に=
−1が選択される。
さらに、上記マイクロコンピュータ内には、同位相スイ
ッチ17がオンされ、かつ車速か所定以上であるときに
選択されて、転舵比を同位相状態からなめらかにOに遷
移させる、遷移時用転舵比データ送出手段30が形成さ
れる。この遷移時用転舵比データとしては車速■に対す
る転舵比にの関係を、たとえば第3図に示すように、比
較的低速領域において車速■が増加するにしたがって転
舵比kが同位相状態である−1からなめらかなカーブで
0に移るようにしてもよいし、第4図に示すように、車
速か所定車速を超えた時点からの時間Tの経過にしたが
って転舵比kを漸次0に移行させるようにしてもよい。
そしてさらにマイクロコンピュータ内には、上記の状況
においてステアリング操作により前輪が中立状態に戻さ
れたことを検知して、AUTO・モードを選択するAU
TO・モード復帰手段31が形成される。
以上の構成を備える四輪操舵装置の動作を、第5図に示
す制御フローチャートにしたがって説明する。
車速センサ16からの車速信号が設定車速、たとえば5
km/h以下であって(S 101でYES)、同位相
スイッチ17がオンされていないとき(S I O6で
No) 、および設定車速以上であって(S 101で
NO)、同位相スイッチ17がオンされていないとき(
S 102でNo)には、四輪操舵装置は通常のAUT
O・モードにあり(S105)、後輪27は、第 図に
示すAt1TO・モード時用転舵比データにしたがって
制御手段11により制御される。具体的には、車速セン
サ16からの車速情報■に応じた転舵比kが読み出され
、この転舵比にと前輪舵角センサ15からの前輪舵角情
報Gこしたがって後輪27の目標転舵角が演算され、こ
れによりステッピングモータ12を回転させるべき方向
およびパルス数が決定され、この制御情報がステッピン
グモータ12に送られるというルーチンが繰り返される
ことになる。なお、第2図うこ示すA[ITO・モーど
用転舵比データの意味は前に説明した通りであり、車速
Vと転舵比にとの関係がこのデータに示される通りに制
御されると、車両は高速、低速の両頭域においてすべり
角のない最適な状態で旋回することができる。
設定車速以下であって同位相スイッチ17がオンされた
場合には(S 106でYES)、AUTO・モードが
キャンセルされて転舵比kが−1となり、この転舵比に
したがって後輪27が制御される。
具体的には、後輪27の目標転舵角が前輪の転舵角と同
方向同角度に算定され、これにしたがって上記と同様に
ステッピングモータ12が回転制御されることにりなる
。この同位相モードにおいてたとえばステアリング操作
により前輪9を右いっばい!二転舵させると、これに応
じて後輪27も右いっばいに転舵される。これにより車
両は、右斜め前方に平行移動することができる。
さらに同位相スイッチ17がオンされたまま車両が設定
車速を超えると(S107−3IOIでNOlおよび、
5102でYES) 、第3図または第4図の遷移時用
転舵比データが選択され、低 ゛速領域における車速増
加にしたがい後輪27がなめらかに転舵比O1すなわち
中立位置に戻されるか、または、一定の短時間をかけて
後輪27がなめらかに中立位置に戻される。このとき、
たとえば前輪9および後輪27が右いっばいに転舵され
た状態から所定車速を超えると、車速増加にしたがい後
輪だけがなめらかに中立位置に戻される。
かりに同位相モードが急激にAUTO・モードに切換ね
る場合を想定すると、後輪が同位相状態から逆位相状態
まで急激に転舵され、設定車速を超えた時点で車体の進
行方向が運転者の意志と無関係に大きく転換されるが、
本発明によればそのようなことはなく、前輪操舵状態に
なめらかに移行するだけである。
さらに、前輪9が中立に戻された時点で、すなわち、車
両が直進状態となった時点で(S 104でYES)
、AUTO・モードに復帰する(S 105)。その後
は、前輪の転舵角と、車速■との関係で最適に選択され
た転舵比にで、後輪27の転舵方向が自動制御される。
以上説明したように、本発明によれば、同位相モード制
御後、車速増加にしたがって自動的に同位相モードがキ
ャンセルされるので、運転者が八〇To・モード選択を
する必要がなくなり、操縦が非常に楽になる。しかも、
同位相モードからAUTO・モードへの転換を、まず後
輪のみを中立にもどし、かつステアリング操作によって
前輪が中立にもどされた時点をもって行なっているので
、運転者にとって違和感がなく、かつ安全性を確保でき
る。Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an example of a four-wheel steering system of the present invention. Here, a conventionally known front wheel steering mechanism 1 is used. That is, in the case of a rank-binion type steering mechanism, the rotation of the steering shaft 3 that rotates together with the steering wheel 2 is converted by the gear box 4 into reciprocating motion of a rack rod 5 in the vehicle width direction, and further The reciprocating motion of the knuckle arm 7.5 is converted into a rotation about the axis 8.8 of the knuckle arm 7.7 via the tie rods 6.6 at both ends, and this rotation of the knuckle arm 7.7 causes the front wheel 9.9 to rotate. is adapted to be steered about the axis 8.8. On the other hand, the rear wheel steering mechanism 10 in this example includes a stepping motor 12 controlled by a control means 11 constituted by a microcomputer;
The power steering device 14 is configured by a known power steering device 14 into which the rotational output of 2 is inputted via a reduction gear device 13. The microcomputer 11 receives signals from a front wheel steering angle sensor 15, a vehicle speed sensor 16, and a same-phase switch 17, and has a control line extending to the stepping motor. As the power steering device 14, a known rack-and-binion type power steering device can be used. That is, the control valve section 19 attached to the input section of the gear box 18 directs the pressure oil from the pump 20 to the gear box 18 according to the rotational direction of the input shaft 21.
Pressure oil is sent to a double-acting power cylinder section 22 formed inside, and this power cylinder section 22 supports the movement of the rack rod 23. The movement of the rack rod 23 is controlled by the knuckle arms 25, 2 by tie rods 24, 24 connected to both ends of the rack rod 23.
5 to rotate this knuckle arm 25.25 to shaft 26.
.. 26, thereby rear wheel 27.2
7 is steered in a predetermined direction about the axis 26.26. In the microcomputer, an AUTO mode steering ratio data sending means 28 is formed which is selected in the AUTO mode and sends out optimum steering ratio information according to the vehicle speed. This steering ratio data for AUTO/mode is as follows:
For example, the relationship between the vehicle speed (2) and the steering ratio as shown in FIG. 2 is selected, and this is stored as a data table in the ROM or non-volatile RAM. The microcomputer also contains steering ratio data for in-phase mode, which is selected when the in-phase switch 17 is turned on and the vehicle speed is below a predetermined value, and sends out steering ratio data as in-phase. Delivery means 29 are formed. As for the same phase mode steering ratio data, the normal steering ratio =
-1 is selected. Furthermore, in the microcomputer, there is a steering wheel for transition, which is selected when the in-phase switch 17 is turned on and the vehicle speed is above a predetermined value to smoothly transition the steering ratio from the in-phase state to O. A ratio data sending means 30 is formed. As the steering ratio data for this transition, the relationship between the steering ratio and the vehicle speed ■ is shown, for example, as shown in FIG. Alternatively, as shown in FIG. 4, the steering ratio k may be gradually changed from -1 to 0 as time T elapses from the time when the vehicle speed exceeds a predetermined vehicle speed. It may also be possible to shift to . Furthermore, in the microcomputer, there is an AU that detects that the front wheels have been returned to the neutral state by steering operation in the above situation and selects the AUTO mode.
TO/mode return means 31 is formed. The operation of the four-wheel steering system having the above configuration will be explained according to the control flowchart shown in FIG. The vehicle speed signal from the vehicle speed sensor 16 is the set vehicle speed, for example 5.
km/h or less (YES in S 101) and the in-phase switch 17 is not turned on (No in S I O6), and if the vehicle speed is above the set vehicle speed (NO in S 101), the in-phase switch 17 is turned on. is not turned on (
S102: No), the four-wheel steering system is a normal AUT.
The vehicle is in the O mode (S105), and the rear wheels 27 are controlled by the control means 11 according to the At1TO mode steering ratio data shown in FIG. Specifically, the steering ratio k corresponding to the vehicle speed information (■) from the vehicle speed sensor 16 is read out, and based on this steering ratio and the front wheel steering angle information G from the front wheel steering angle sensor 15, the target of the rear wheels 27 is determined. The steering angle is calculated, the direction and number of pulses in which the stepping motor 12 should be rotated is determined, and this control information is sent to the stepping motor 12. This routine is repeated. The meaning of the A[ITO/mode steering ratio data shown on the side of Figure 2] is as explained above, and the relationship between the vehicle speed V and the steering ratio is controlled as shown in this data. This allows the vehicle to turn in an optimal state with no slip angle at both high and low speeds. If the vehicle speed is below the set vehicle speed and the in-phase switch 17 is turned on (YES in S106), the AUTO mode is canceled and the steering ratio k becomes -1, and the rear wheels 27 are rotated according to this steering ratio. controlled. Specifically, the target steering angle of the rear wheels 27 is calculated to be the same direction and angle as the steering angle of the front wheels, and the stepping motor 12 is rotationally controlled in the same manner as described above. In this same phase mode, for example, by steering the front wheel 9, turn it to the right! When the vehicle is steered twice, the rear wheels 27 are also steered all the way to the right. This allows the vehicle to move in parallel diagonally forward to the right. Furthermore, if the vehicle exceeds the set vehicle speed with the in-phase switch 17 turned on (NOl and
5102), the steering ratio data for transition shown in FIG. 3 or 4 is selected, and as the vehicle speed increases in the low speed region, the rear wheels 27 are smoothly returned to the steering ratio O1, that is, the neutral position. Alternatively, the rear wheels 27 are smoothly returned to the neutral position over a certain period of time. At this time,
For example, when the front wheels 9 and the rear wheels 27 are steered all the way to the right and the vehicle speed exceeds a predetermined value, only the rear wheels are smoothly returned to the neutral position as the vehicle speed increases. Assuming that the in-phase mode suddenly switches to the AUTO mode, the rear wheels will be abruptly steered from the in-phase state to the anti-phase state, and when the set vehicle speed is exceeded, the direction of travel of the vehicle will change to the driver's direction. Although it changes drastically regardless of the will,
According to the present invention, such a situation does not occur, and there is only a smooth transition to the front wheel steering state. Further, when the front wheels 9 are returned to neutral, that is, when the vehicle is traveling straight (YES in S104)
, returns to AUTO mode (S105). Thereafter, the steering direction of the rear wheels 27 is automatically controlled using a steering ratio that is optimally selected based on the relationship between the front wheel steering angle and the vehicle speed (2). As explained above, according to the present invention, after the same phase mode control, the same phase mode is automatically canceled as the vehicle speed increases, so the driver does not need to select the 80 To mode, and becomes very easy. Moreover,
The transition from same-phase mode to AUTO mode is performed by first returning only the rear wheels to neutral, and then at the point when the front wheels are returned to neutral by steering operation, so there is no discomfort for the driver and safety is maintained. Can be secured.
第1図は本発明の四輪操舵装置の全体構成図、第2図は
AUTO・モード時用転舵比データの一例を示すグラフ
、第3図および第4図は遷移時用転舵比データの例を示
すグラフ、第5図は本発明の四輪操舵装置の制御の流れ
の一例を示すフローチャート、第6図は本発明以外の四
輪操舵装置における問題を説明するためのグラフである
。
l・・・前輪転舵機構、3・・・ステアリングシャフト
、10・・・後輪転舵機構、11・・・制御手段、17
・・・同位相スイッチ、28・・・A11TO・モード
用転舵比デーク送出手段、29・・・同位相モード用転
舵比デーク送出手段、30・・・遷移時用転舵比データ
送出手段、31・・・^UTO・モード復帰手段。Figure 1 is an overall configuration diagram of the four-wheel steering system of the present invention, Figure 2 is a graph showing an example of steering ratio data for AUTO/mode, and Figures 3 and 4 are steering ratio data for transition. FIG. 5 is a flowchart showing an example of the control flow of the four-wheel steering system of the present invention, and FIG. 6 is a graph for explaining problems in a four-wheel steering system other than the present invention. l... Front wheel steering mechanism, 3... Steering shaft, 10... Rear wheel steering mechanism, 11... Control means, 17
. . . same phase switch, 28 . . . steering ratio data transmission means for A11TO mode, 29 . . . steering ratio data transmission means for same phase mode, 30 . . . steering ratio data transmission means for transition. , 31...^UTO mode return means.
Claims (1)
させる前輪転舵機構と、 制御手段によって制御され、かつ後輪を各転舵比データ
にしたがって転舵しうる後輪転舵機構と、 AUTO・モードから同位相モードに切換える同位相ス
イッチと、 AUTO・モード時に選択されて、後輪の前輪に対する
転舵比が車速に応じて最適となるように設定された転舵
比データを制御手段に送出する、AUTO・モード用転
舵比データ送出手段と、 同位相スイッチがオンされ、かつ車速が所定以下である
ときに選択されて、同位相としての転舵比データを制御
手段に送出する、同位相モード用転舵比データ送出手段
と、 同位相スイッチがオンされ、かつ車速が所定以上である
ときに選択されて、転舵比を同位相状態からなめらかに
0に遷移させる、遷移時用転舵比データ送出手段と、 上記遷移時用転舵比データにしたがって後輪舵角が中立
位置に復帰後、前輪舵角が0復帰したときAUTO・モ
ードを選択するAUTO・モード復帰手段とを備えるこ
とを特徴とする、四輪操舵装置。(1) A front wheel steering mechanism that steers the front wheels according to the rotation of the steering shaft; a rear wheel steering mechanism that is controlled by a control means and that can steer the rear wheels according to each steering ratio data; An in-phase switch that switches from mode to in-phase mode, and steering ratio data that is selected in AUTO mode and is set so that the steering ratio of the rear wheels to the front wheels is optimal according to the vehicle speed is sent to the control means. AUTO/mode steering ratio data sending means, which is selected when the same phase switch is turned on and the vehicle speed is below a predetermined value, and sends steering ratio data as the same phase to the control means. A phase mode steering ratio data sending means, and a transition time switch that is selected when the in-phase switch is turned on and the vehicle speed is above a predetermined value to smoothly transition the steering ratio from the in-phase state to 0. A steering ratio data sending means; and an AUTO/mode return means for selecting an AUTO mode when the front wheel steering angle returns to 0 after the rear wheel steering angle returns to the neutral position in accordance with the transition steering ratio data. A four-wheel steering device characterized by:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60221516A JPH0637178B2 (en) | 1985-10-03 | 1985-10-03 | Four-wheel steering system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60221516A JPH0637178B2 (en) | 1985-10-03 | 1985-10-03 | Four-wheel steering system |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6280174A true JPS6280174A (en) | 1987-04-13 |
JPH0637178B2 JPH0637178B2 (en) | 1994-05-18 |
Family
ID=16767936
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP60221516A Expired - Lifetime JPH0637178B2 (en) | 1985-10-03 | 1985-10-03 | Four-wheel steering system |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0637178B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5379220A (en) * | 1991-07-29 | 1995-01-03 | Caterpillar Inc. | Electronic steering control |
GB2461290A (en) * | 2008-06-26 | 2009-12-30 | One80 Ltd | Rear wheel steering system. |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5981271A (en) * | 1982-10-30 | 1984-05-10 | Mazda Motor Corp | 4-wheel steering device of vehicle |
-
1985
- 1985-10-03 JP JP60221516A patent/JPH0637178B2/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5981271A (en) * | 1982-10-30 | 1984-05-10 | Mazda Motor Corp | 4-wheel steering device of vehicle |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5379220A (en) * | 1991-07-29 | 1995-01-03 | Caterpillar Inc. | Electronic steering control |
GB2461290A (en) * | 2008-06-26 | 2009-12-30 | One80 Ltd | Rear wheel steering system. |
GB2461290B (en) * | 2008-06-26 | 2012-12-05 | One80 Ltd | Rear wheel steering system |
Also Published As
Publication number | Publication date |
---|---|
JPH0637178B2 (en) | 1994-05-18 |
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