JP2619657B2 - Control method of four-wheel steering device for automobile - Google Patents
Control method of four-wheel steering device for automobileInfo
- Publication number
- JP2619657B2 JP2619657B2 JP62269908A JP26990887A JP2619657B2 JP 2619657 B2 JP2619657 B2 JP 2619657B2 JP 62269908 A JP62269908 A JP 62269908A JP 26990887 A JP26990887 A JP 26990887A JP 2619657 B2 JP2619657 B2 JP 2619657B2
- Authority
- JP
- Japan
- Prior art keywords
- wheel steering
- rear wheel
- steering
- pressure difference
- hydraulic
- 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
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
- B62D7/159—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 computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は自動車用４輪操舵装置の制御方法に関するも
のである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a four-wheel steering device for an automobile.
従来の技術 自動車において、前輪の操舵に応じて後輪を転舵させ
るようにした４輪操舵装置は従来より種々開発され、例
えば特開昭61−57466号公報にて公開されている。2. Description of the Related Art In a motor vehicle, various four-wheel steering devices in which the rear wheels are steered according to the steering of the front wheels have been conventionally developed, and are disclosed, for example, in Japanese Patent Application Laid-Open No. 61-57466.
上記のような４輪操舵装置は、従来は一般にハンドル
操作角等により検出した前輪舵角と車速センサにて検出
した車速とから後輪操舵角（転舵方向を含む）目標値を
決定し、後輪操舵用アクチュエータ（油圧アクチュエー
タ或は電動モータ等）を作動させて上記目標値通りに後
輪を転舵させるようになっており、例えば低車速域では
後輪を前輪とは逆方向に転舵させて旋回性の向上をはか
り、中，高車速域では後輪を前輪と同方向に転舵させて
安定性の向上をはかると言う制御を行っているのが普通
である。Conventionally, such a four-wheel steering device generally determines a rear wheel steering angle (including a steering direction) target value from a front wheel steering angle detected by a steering wheel operation angle or the like and a vehicle speed detected by a vehicle speed sensor. The rear wheel steering actuator (hydraulic actuator or electric motor, etc.) is operated to steer the rear wheel according to the target value. For example, in a low vehicle speed range, the rear wheel rotates in the opposite direction to the front wheel. In general, control is performed to steer the steering wheel so as to improve turning performance, and to steer the rear wheel in the same direction as the front wheel in the middle and high vehicle speed ranges to improve the stability.
又後輪舵角をハンドル操作トルク等により検出した前
輪舵力と車速センサにより検出した車速とから制御する
ようにしたものも近年開発されている。In recent years, a rear wheel steering angle is controlled based on a front wheel steering force detected by a steering wheel operating torque or the like and a vehicle speed detected by a vehicle speed sensor.
発明が解決しようとする問題点 上記のような４輪操舵装置は、車速に応じて変化する
前輪舵角（又は舵力）−後輪舵角の特性を予じめコント
ロールユニットに設定しておき、前輪舵角（又は舵力）
情報と車速情報とからコントロールユニットが上記設定
特性に基づき後輪操舵角目標値を決定し、この目標値通
りに後輪を転舵させると言う制御を行うものである。Problems to be Solved by the Invention In the four-wheel steering device as described above, the characteristic of front wheel steering angle (or steering force) -rear wheel steering angle that changes according to the vehicle speed is set in the control unit in advance. , Front wheel steering angle (or steering force)
The control unit determines the rear wheel steering angle target value based on the information and the vehicle speed information based on the set characteristics, and performs control to turn the rear wheel according to the target value.
しかし車両の運動性能は路面状態によって大きく影響
され、特に荒れた路面（例えば砂利路等）ではドライバ
の予期しない挙動を示すことがあり安定性が悪くなる。However, the kinetic performance of the vehicle is greatly affected by the road surface condition, and particularly on a rough road surface (for example, a gravel road), the driver may behave unexpectedly, and the stability is deteriorated.
本発明は上記の点に対処することを主目的とするもの
である。The present invention has as its main object to address the above points.
問題点を解決するための手段 本発明は、油圧式パワステアリング装置を装備した自
動車の４輪操舵装置において、油圧式パワステアリング
装置のパワシリンダの左右油圧室の油圧差を検出する手
段を設け、該油圧差検出手段からの油圧差信号の変動周
波数のうちの所定値より大きい変動周波数における変動
成分の振幅の平方和が所定時間内に設定値以上となった
場合悪路と判断し、後輪の同相方向操舵量を増大させる
制御を行うことを特徴とするものである。Means for Solving the Problems The present invention provides, in a four-wheel steering system of an automobile equipped with a hydraulic power steering device, means for detecting a hydraulic pressure difference between left and right hydraulic chambers of a power cylinder of the hydraulic power steering device, If the sum of the squares of the amplitudes of the fluctuation components at a fluctuation frequency larger than a predetermined value among the fluctuation frequencies of the oil pressure difference signal from the oil pressure difference detection means becomes equal to or larger than a set value within a predetermined time, it is determined that the road is bad. The control for increasing the in-phase direction steering amount is performed.
作用 上記により、例えば砂利路等の荒れた路面を走行する
ときはコントロールユニットが油圧式パワステアリング
装置の油圧差変動から路面の荒さを的確に推定し、標準
的な設定特性にて後輪を転舵させる場合より後輪に同相
方向の大なる舵角を与えることによって、車両挙動の変
化を少くし、操縦安定性の向上をはかることができる。Effect As described above, when traveling on rough roads such as gravel roads, the control unit accurately estimates the road surface roughness from the hydraulic pressure difference fluctuation of the hydraulic power steering device and turns the rear wheels with standard setting characteristics. By giving a larger steering angle in the in-phase direction to the rear wheels than in the case of steering, changes in vehicle behavior can be reduced and steering stability can be improved.
又、油圧式パワステアリング装置にもともと装備され
ているパワシリンダの左右油圧室の油圧差を用いて路面
状態を判断する構成を採っているので、例えば車体の上
下動を検出するセンサ等の新規な路面状態検出手段の追
加なしに、精度のよい路面状態の検出が可能となり、構
成の簡略化及びコストの低廉化をはかることができる。In addition, since the road surface condition is determined using the hydraulic pressure difference between the left and right hydraulic chambers of the power cylinder originally provided in the hydraulic power steering device, a new road surface such as a sensor for detecting the vertical movement of the vehicle body is employed. The road surface condition can be detected with high accuracy without adding a state detecting means, and the configuration can be simplified and the cost can be reduced.
実施例 以下本発明の実施例を附図を参照して説明する。Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.
第１図において、１はハンドル、２は前輪であり、該
ハンドル１から前輪２に至る公知の前輪操舵系統にはハ
ンドル１の操舵トルクに応じて作動するコントロールバ
ルブ３と、該コントロールバルブ３の作動により油圧ポ
ンプ４の吐出油圧が左右いずれか一方に導入される左右
の油室をもったパワシリンダ５とからなる公知の油圧式
パワステアリング装置が設けられている。In FIG. 1, reference numeral 1 denotes a steering wheel, 2 denotes a front wheel, and a known front wheel steering system extending from the steering wheel 1 to the front wheel 2 includes a control valve 3 that operates according to the steering torque of the steering wheel 1; There is provided a known hydraulic power steering device including a power cylinder 5 having left and right oil chambers into which the discharge hydraulic pressure of the hydraulic pump 4 is introduced into one of the right and left by operation.
6a,6bは上記パワシリンダの左右の油室の油圧を検出
する左右の油圧センサであり、該油圧センサ6a,6bが検
出した左右の油圧信号は演算増幅装置７に入力されこゝ
で左右の油圧差を演算し、その油圧差に応じた信号をコ
ントロールユニット９に入力する。Reference numerals 6a and 6b denote left and right oil pressure sensors for detecting the oil pressure in the left and right oil chambers of the power cylinder. Left and right oil pressure signals detected by the oil pressure sensors 6a and 6b are input to the operational amplifier 7, and the left and right oil pressure signals The difference is calculated, and a signal corresponding to the oil pressure difference is input to the control unit 9.
上記において、油圧式パワステアリング装置はハンド
ル１の操舵トルクに応じた油圧補助力を発生させるもの
であるから上記油圧差はハンドル１の操舵トルクに対応
しており、従って演算増幅装置７からコントロールユニ
ット９に入力される信号は前輪舵力に対応した舵力信号
である。In the above description, the hydraulic power steering device generates a hydraulic assisting force in accordance with the steering torque of the steering wheel 1, and thus the hydraulic pressure difference corresponds to the steering torque of the steering wheel 1. The signal input to 9 is a steering force signal corresponding to the front wheel steering force.
８は車速に応じた車速信号を発する車速センサであ
り、該車速信号もコントロールルユニット９に入力され
る。Reference numeral 8 denotes a vehicle speed sensor that emits a vehicle speed signal corresponding to the vehicle speed. The vehicle speed signal is also input to the control unit 9.
コントロールユニット９は、予じめ設定されている車
速−舵力−後輪舵角特性に基づき、上記入力された舵力
信号および車速信号から後輪操舵角目標値を決定し、そ
れに基づきモータ等の後輪操舵用アクチュエータ10に出
力信号を発し、電磁クラッチ11,例えばリンク機構等よ
りなる後輪操舵機構12を介して後輪13を転舵させ、後輪
は後輪舵角を検出する後輪舵角センサ14の後輪舵角信号
によるフィードバック制御により上記目標値通りの舵角
に転舵される。The control unit 9 determines a rear wheel steering angle target value from the input steering force signal and the vehicle speed signal based on a vehicle speed-steering force-rear wheel steering angle characteristic set in advance, and based on the determined value, a motor or the like is used. An output signal is issued to the rear wheel steering actuator 10, and the rear wheel 13 is steered via an electromagnetic clutch 11, for example, a rear wheel steering mechanism 12 including a link mechanism, and the rear wheel detects the rear wheel steering angle. By the feedback control based on the rear wheel steering angle signal of the wheel steering angle sensor 14, the steering is turned to the steering angle according to the target value.
尚第１図において15はモータ回転速度センサであり、
後輪操舵用アクチュエータ10として図示のようにモータ
を用いたときは該モータ回転速度センサ15の信号により
モータ速度は制御される。In FIG. 1, reference numeral 15 denotes a motor rotation speed sensor,
When a motor is used as the rear wheel steering actuator 10 as shown in the figure, the motor speed is controlled by the signal of the motor rotation speed sensor 15.
コントロールユニット９には、第２図に示すように演
算増幅装置７より入力される油圧差信号と車速センサ８
から入力される車速信号とから後輪操舵角目標値を決定
する後輪操舵角演算部91が設けられていると共に、上記
油圧差信号部から悪路かどうかを判断する悪路判定部92
が設けられている。As shown in FIG. 2, the control unit 9 includes a hydraulic pressure difference signal input from the operational amplifier 7 and a vehicle speed sensor 8.
A rear wheel steering angle calculation unit 91 for determining a rear wheel steering angle target value from a vehicle speed signal input from the vehicle speed signal is provided, and a rough road determination unit 92 for determining whether the road is a rough road from the hydraulic pressure difference signal unit.
Is provided.
即ち、油圧差信号はローパスフィルタLPFにて平滑処
理されて後輪操舵角演算部91に入力され、例えばそのと
きの車速での油圧差（舵力）−後輪舵角設定特性が第３
図実線示Ａであったとすると、その設定特性Ａに基づい
て後輪操舵角目標値を決定し、モータ等の後輪操舵用ア
クチュエータ10に出力信号を発し後輪を決定した目標値
通りに転舵させるものである。That is, the oil pressure difference signal is smoothed by the low-pass filter LPF and input to the rear wheel steering angle calculation unit 91. For example, the oil pressure difference (steering force) at the vehicle speed at that time-the rear wheel steering angle setting characteristic is the third.
If it is indicated by a solid line A in the figure, a rear wheel steering angle target value is determined based on the set characteristic A, an output signal is issued to a rear wheel steering actuator 10 such as a motor, and the rear wheel is rotated according to the determined target value. To steer.
油圧差信号はハイパスフィルタHPFを介して悪路判定
部92にも入力され、第４図に示すような方法で走行路面
が悪路であるかどうかを判定し、悪路であると判断した
ときは後輪操舵角演算部91に信号を発して油圧差−後輪
舵角設定特性を例えば第３図実線示Ａより点線示Ｂの如
く同相方向操舵量を大とする方向に変更させ、後輪操舵
角演算部91は点線示Ｂの特性に基づき後輪操舵角目標値
を決定することにより後輪の同相方向操舵量を良路の場
合に比し増大させる。The hydraulic pressure difference signal is also input to the rough road determination unit 92 via the high-pass filter HPF, and it is determined whether or not the traveling road surface is a rough road by a method as shown in FIG. Sends a signal to the rear wheel steering angle calculation unit 91 to change the hydraulic pressure difference-rear wheel steering angle setting characteristic from the solid line A in FIG. The wheel steering angle calculation unit 91 determines the rear wheel steering angle target value based on the characteristic indicated by the dotted line B, thereby increasing the in-phase steering amount of the rear wheels as compared with the case of a good road.
荒れた路面では路面の影響を受けて、例えば砂利路で
のスラローム試験での油圧センサ6a,6bの各センサ信号
を示す第５図（イ）のように、油圧信号の変動が細かく
なり、従ってコントロールユニット９に入力される油圧
差信号も第５図（ロ）に示すように高周波数成分が混在
するようになる。On rough roads, under the influence of the road surface, for example, as shown in FIG. 5 (a) showing each sensor signal of the hydraulic sensors 6a and 6b in a slalom test on a gravel road, the fluctuation of the hydraulic signal becomes fine, The hydraulic pressure difference signal input to the control unit 9 also contains high frequency components as shown in FIG.
そこで、油圧差信号が入力されたとき、先ずハイパス
フィルタHPFにて油圧差信号の周波数ｆが所定値f0より
大である変動周波数における変動成分だけ取り出し、次
にｆ＞f0の変動成分の振幅の平方和ａを求める。そして
所定時間内の振幅の平方和ａと設定値a0とを比較し、ａ
＞a0であった場合悪路であると判断し、前述したように
後輪操舵角演算部91に後輪操舵量変更指令を発し、後輪
操舵量を安定側（同相方向）に増加させることにより、
荒れた路面での車両挙動の変化を減少させ、操縦安定性
の向上をはかることができるものである。Therefore, when the hydraulic pressure difference signal is input, first, only the fluctuation component at the fluctuation frequency where the frequency f of the hydraulic pressure difference signal is larger than the predetermined value f 0 is extracted by the high-pass filter HPF, and then the fluctuation component of f> f 0 Find the sum of squares a of the amplitude. Then, the square sum a of the amplitude within a predetermined time is compared with the set value a 0, and a
> Determined to be bad road if was a 0, increased to emit the rear wheel steering amount change command to the rear wheel steering angle calculation section 91 as described above, the rear wheel steering amount stable side (in-phase direction) By doing
It is intended to reduce changes in vehicle behavior on a rough road surface and improve steering stability.
尚後輪操舵用アクチュエータ10,後輪操舵機構12等は
図示実施例に限らず、従来より公知の任意のものを採用
できる。Note that the rear wheel steering actuator 10, the rear wheel steering mechanism 12, and the like are not limited to the illustrated embodiment, and any conventionally known ones can be adopted.
発明の効果 以上のように本発明によれば、油圧式パワステアリン
グ装置のパワシリンダの左右の油圧室の油圧差を検出
し、該油圧差と車速とから後輪操舵角目標値を決定しそ
の目標値通りに後輪を転舵作動させる自動車の４輪操舵
装置において、上記油圧差の変動から路面が悪路である
かどうかを極めて的確に判断し、悪路であると判断した
とき後輪の同相方向の操舵量を増大させると言う制御を
行うことにより、悪路走行時の車両挙動の変化を減少さ
せ操縦安定性の著しい向上をはかることができるもので
ある。Effects of the Invention As described above, according to the present invention, a hydraulic pressure difference between left and right hydraulic chambers of a power cylinder of a hydraulic power steering device is detected, and a rear wheel steering angle target value is determined from the hydraulic pressure difference and the vehicle speed to determine the target value. In a four-wheel steering system for an automobile that steers the rear wheels according to a value, it is extremely accurately determined whether or not the road surface is a rough road based on the fluctuation of the hydraulic pressure difference. By performing control to increase the amount of steering in the same phase, it is possible to reduce changes in vehicle behavior when traveling on a rough road and significantly improve steering stability.
更に、本発明では、油圧式パワステアリング装置にも
ともと装備されているパワシリンダの左右油圧室の油圧
差を用いて路面状態の判断を行う構成を採っているの
で、路面状態判断のための新たな検出手段の追加は全く
不要であり、構成の簡略化及びコストの低廉化をはかる
ことができるもので、実用上多大の効果をもたらし得る
ものである。Further, the present invention employs a configuration in which the road surface state is determined using the hydraulic pressure difference between the left and right hydraulic chambers of the power cylinder originally provided in the hydraulic power steering device, so that a new detection for determining the road surface state is performed. No additional means is required at all, and the structure can be simplified and the cost can be reduced, and a great effect can be obtained in practical use.
第１図は本発明の一実施例を示す平面説明図、第２図は
コントロールユニット部における制御系統のブロック
図、第３図は油圧差−後輪舵角特性の一例を示す図、第
４図は悪路判定方法を示すフローチャート、第５図
（イ），（ロ）は砂利路でのスラローム試験における油
圧センサ信号波形図及び油圧差信号波形図である。 １……ハンドル、２……前輪、５……パワシリンダ、6
a,6b……油圧センサ、７……演算増幅装置、８……車速
センサ、９……コントロールユニット、10……後輪操舵
用アクチュエータ、12……後輪操舵機構、13……後輪、
14……後輪舵角センサ。FIG. 1 is an explanatory plan view showing one embodiment of the present invention, FIG. 2 is a block diagram of a control system in a control unit, FIG. 3 is a diagram showing an example of a hydraulic pressure difference-rear wheel steering angle characteristic, FIG. Fig. 5 is a flowchart showing a method for determining a rough road, and Figs. 5 (a) and 5 (b) are a waveform diagram of a hydraulic pressure sensor signal and a waveform diagram of a hydraulic pressure difference signal in a slalom test on a gravel road. 1 ... handle, 2 ... front wheel, 5 ... power cylinder, 6
a, 6b: hydraulic pressure sensor, 7: operational amplifier, 8: vehicle speed sensor, 9: control unit, 10: rear-wheel steering actuator, 12: rear-wheel steering mechanism, 13: rear wheel,
14 ... Rear wheel steering angle sensor.
Claims (1)
動車の４輪操舵装置において、油圧式パワステアリング
装置のパワシリンダの左右油圧室の油圧差を検出し、該
油圧差と車速とから後輪操舵角制御を行うと共に、上記
油圧差の変動周波数のうちの所定値より大きい変動周波
数における変動成分の振幅の所定時間内の平方和が設定
値より大であったとき悪路と判断し後輪の同相方向の操
舵量を増大させる制御を行うことを特徴とする自動車用
４輪操舵装置の制御方法。In a four-wheel steering system of an automobile equipped with a hydraulic power steering device, a hydraulic pressure difference between left and right hydraulic chambers of a power cylinder of the hydraulic power steering device is detected, and a rear wheel steering angle is determined from the hydraulic pressure difference and a vehicle speed. When the sum of squares of the amplitude of the fluctuation component within a predetermined time at a fluctuation frequency larger than a predetermined value among the fluctuation frequencies of the hydraulic pressure difference is larger than a set value, it is determined that the road is a bad road and the rear wheel is in phase. A control method for a four-wheel steering apparatus for an automobile, wherein control is performed to increase a steering amount in a direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62269908A JP2619657B2 (en) | 1987-10-26 | 1987-10-26 | Control method of four-wheel steering device for automobile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62269908A JP2619657B2 (en) | 1987-10-26 | 1987-10-26 | Control method of four-wheel steering device for automobile |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01111572A JPH01111572A (en) | 1989-04-28 |
| JP2619657B2 true JP2619657B2 (en) | 1997-06-11 |
Family
ID=17478898
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62269908A Expired - Lifetime JP2619657B2 (en) | 1987-10-26 | 1987-10-26 | Control method of four-wheel steering device for automobile |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2619657B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5967170A (en) * | 1982-10-09 | 1984-04-16 | Nippon Seiko Kk | Steering device of car |
| JPS62131881A (en) * | 1985-12-04 | 1987-06-15 | Toyota Motor Corp | Rear wheel steering control device for front and rear wheel steering vehicle |
-
1987
- 1987-10-26 JP JP62269908A patent/JP2619657B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01111572A (en) | 1989-04-28 |
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