JP2699585B2 - Auxiliary steering angle control device for front wheel drive vehicles - Google Patents
Auxiliary steering angle control device for front wheel drive vehiclesInfo
- Publication number
- JP2699585B2 JP2699585B2 JP1273190A JP27319089A JP2699585B2 JP 2699585 B2 JP2699585 B2 JP 2699585B2 JP 1273190 A JP1273190 A JP 1273190A JP 27319089 A JP27319089 A JP 27319089A JP 2699585 B2 JP2699585 B2 JP 2699585B2
- Authority
- JP
- Japan
- Prior art keywords
- steering angle
- angle control
- auxiliary steering
- control amount
- value
- 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
Landscapes
- 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、前輪操舵時に前輪または後輪の少なくとも
一方を補助転舵することで最適な旋回性能を得る前輪駆
動車用補助舵角制御装置に関する。Description: BACKGROUND OF THE INVENTION The present invention relates to an auxiliary steering angle control device for a front wheel drive vehicle that obtains an optimum turning performance by auxiliary steering of at least one of a front wheel and a rear wheel during front wheel steering. About.
(従来の技術) 従来、駆動輪スリップを制御入力とする前後輪操舵車
両の後輪舵角制御装置としては、例えば、特開昭62−71
761号公報に記載されている装置が知られている。2. Description of the Related Art Conventionally, as a rear wheel steering angle control device for a front-rear-wheel steering vehicle using a drive wheel slip as a control input, for example, Japanese Patent Application Laid-Open No. Sho 62-71
An apparatus described in Japanese Patent No. 761 is known.
この従来出典には、車両加速時に発生する駆動輪スリ
ップ状態を駆動輪と非駆動輪との回転速度差により検出
し、該回転速度差に応じて後輪を補助転舵制御し、旋回
時に駆動スリップ(コーナリングフォースの低下)に起
因したステア特性の変化を防止する技術が示されてい
る。According to this conventional source, a driving wheel slip state occurring at the time of vehicle acceleration is detected based on a rotational speed difference between a driving wheel and a non-driving wheel, and the rear wheels are subjected to auxiliary steering control in accordance with the rotational speed difference to drive the vehicle during turning. There is disclosed a technique for preventing a change in steer characteristics due to slip (reduction in cornering force).
具体的には、前後輪回転速度差の増加に従って後輪を
同相又は逆相側に補助転舵するもので、その目標舵角比
は、 K*=K*f(g)=K*(α*g) 但し、K*;目標舵角比 K ;車速対応舵角比 α ;比例定数 g ;前後回転速度差 で与えられ、前後輪回転速度差の発生と同時に前後輪舵
角比を変更する構成となっている。Specifically, the rear wheels are auxiliary-steered to the same phase or opposite phase according to the increase in the front and rear wheel rotation speed difference, and the target steering angle ratio is K * = K * f (g) = K * (α * G) However, K * ; target steering angle ratio K; vehicle speed corresponding steering angle ratio α; proportionality constant g; given by front / rear rotation speed difference, and changes front / rear wheel steering angle ratio at the same time as occurrence of front / rear wheel rotation speed difference. It has a configuration.
(発明が解決しようとする課題) しかしながら、上記従来制御によると、車速により目
標舵角比のゲインは変わるものの全車駆動車の場合に
は、駆動スリップ時に後輪を逆相側に修正し、後輪駆動
車の場合には駆動スリップ時に後輪を同相側に修正する
事になる。However, according to the conventional control described above, although the gain of the target steering angle ratio changes depending on the vehicle speed, in the case of an all-vehicle drive vehicle, the rear wheels are corrected to the opposite phase during the drive slip, In the case of a wheel drive vehicle, the rear wheels are corrected to the same phase during a drive slip.
ここで、後輪を同相側に修正する事と逆相側に修正す
る事とを比較すると、後者の逆相修正場合にはオーバス
テア方向のモーメントを与えることになり、車両を不安
定側にする事になるのは言うまでもない。Here, comparing the correction of the rear wheels to the in-phase side and the correction of the rear wheels to the opposite phase, when the latter is reversed, a moment in the oversteer direction is given, and the vehicle is made unstable. Needless to say,
また、車両の操安性は車速が大になる程、要求される
事も言うまでもない。Needless to say, the higher the vehicle speed, the higher the maneuverability of the vehicle.
以上の点から上記従来技術を評価してみると、駆動輪
スリップに逆相性が要求される前輪駆動車の場合、駆動
スリップ量を実際よりも大きく誤検出した場合には、必
要以上に逆相修正されてしまい、車両が不安定になる。
特に、操安性が重視される高速時には、上記逆相修正に
より車両スピンを発生させることがあり、好ましくな
い。From the above points, when evaluating the above-described conventional technology, in the case of a front-wheel drive vehicle in which the drive wheel slip is required to have the opposite phase, when the drive slip amount is erroneously detected larger than the actual amount, the reverse phase is more than necessary. Corrected and the vehicle becomes unstable.
In particular, at high speeds in which maneuverability is important, the above-described reverse phase correction may cause a vehicle spin, which is not preferable.
尚、駆動スリップ量を実際よりも大きく誤検出する場
合としては、例えば、一般のフロントヘビーの前輪駆動
車では、前後タイヤ動半径のうち前側タイヤ径が輪荷重
で小さくなり、駆動スリップ量の検出値が真の駆動スリ
ップ量に比べて大きな値として誤検出してしまう。In the case where the drive slip amount is erroneously detected larger than the actual one, for example, in a general front heavy front wheel drive vehicle, the front tire diameter of the front and rear tire radius becomes smaller due to the wheel load, and the drive slip amount is detected. The value is erroneously detected as a value larger than the true drive slip amount.
本発明は、上述のような問題に着目してなされたもの
で、前輪操舵時に前輪または後輪の少なくとも一方を補
助転舵する前輪駆動車用補助舵角制御装置において、過
大なドリフトアウトの発生を防止しながら、低速旋回時
における小回り性の確保と、高速旋回時における安定性
の確保とを達成する事を課題とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem. In an auxiliary steering angle control device for a front wheel drive vehicle that assists steering of at least one of a front wheel and a rear wheel during front wheel steering, excessive drift-out occurs. It is an object of the present invention to secure small turnability during low-speed turning and to ensure stability during high-speed turning while preventing the occurrence of a vehicle.
(課題を解決するための手段) 上記課題を解決するために本発明の前輪駆動車用補助
舵角制御装置では、前後輪駆動回転速度差により検出し
た駆動スリップ量と、高車速ほど大きな値に設定される
オフセット値との差によりドリフト防止の補助舵角制御
を行なう手段とした。(Means for Solving the Problems) In order to solve the above problems, the front wheel drive vehicle auxiliary steering angle control device of the present invention increases the drive slip amount detected by the difference between the front and rear wheel drive rotation speeds, and increases the value as the vehicle speed increases. A means for performing auxiliary steering angle control for preventing drift based on a difference from the set offset value.
即ち、第1図のクレーム対応図に示すように、前輪を
駆動輪とする前輪駆動車であって、ドライバーによるハ
ンドル操作に応じて前輪を操舵する前輪操舵機構aと、 外部からの駆動指令に応じて前輪または後輪の少なく
とも一方に補助舵角制御量を与える補助転舵機構bと、 前輪操舵量を検出する前輪操舵量検出手段cと、 前輪操舵量に応じて与える基本補助舵角制御量を決定
する基本補助舵角制御量決定手段dと、 前輪回転速度と後輪回転速度との差を検出する前後輪
回転速度差検出手段eと、 車速を検出する車速検出手段fと、 前後輪回転速度差のオフセット値を、低速時はオーバ
ステア側に舵角修正され易い小さな値に設定し、車速の
増大に従って次第に大きくなる値により設定し、高速時
はオーバステア側に舵角修正されにくい大きな値に設定
するオフセット値設定手段gと、 前後輪回転速度差検出値と車速対応オフセット設定値
との差が増加するに従ってオーバステア側に修正する修
正補助舵角制御量を決定する修正補助舵角制御量決定手
段hと、 前記基本補助舵角制御量と修正補助舵角制御量との和
により補助舵角制御量を決定する補助舵角制御量決定手
段iと、 決定した補助舵角制御量が得られる駆動指令を前記補
助転舵機構bに出力する出力手段jと、 を備えていることを特徴とする。That is, as shown in the claim correspondence diagram of FIG. 1, a front wheel drive vehicle having front wheels as drive wheels, a front wheel steering mechanism a for steering the front wheels in response to a steering operation by a driver, and a drive command from outside An auxiliary steering mechanism b for providing an auxiliary steering angle control amount to at least one of the front wheel and the rear wheel, a front wheel steering amount detecting means c for detecting the front wheel steering amount, and a basic auxiliary steering angle control for providing a front wheel steering amount. Basic auxiliary steering angle control amount determination means d for determining the amount, front and rear wheel rotation speed difference detection means e for detecting a difference between the front wheel rotation speed and the rear wheel rotation speed, vehicle speed detection means f for detecting the vehicle speed, The offset value of the wheel rotational speed difference is set to a small value at which the steering angle is easily corrected to the oversteer side at low speed, and is set to a value that gradually increases as the vehicle speed increases, and the steering angle is hardly corrected to the oversteer side at high speed. An offset value setting means g for setting a correct auxiliary steering angle control amount for correcting the oversteer side as the difference between the front and rear wheel rotational speed difference detection value and the vehicle speed corresponding offset setting value increases. Angle control amount determining means h; auxiliary steering angle control amount determining means i for determining an auxiliary steering angle control amount based on a sum of the basic auxiliary steering angle control amount and the corrected auxiliary steering angle control amount; And output means j for outputting a drive command for obtaining the amount to the auxiliary turning mechanism b.
(作 用) ドライバーによるハンドル操作で前輪操舵機構aを介
して前輪を操舵すると、前輪操舵量検出手段cにより前
輪操舵量が検出され、基本補助舵角制御量決定手段dに
おいて、前輪操舵量に応じて与える基本補助舵角制御量
が決定される。(Operation) When the front wheels are steered through the front wheel steering mechanism a by the driver's steering operation, the front wheel steering amount is detected by the front wheel steering amount detecting means c, and the basic auxiliary steering angle control amount determining means d determines the front wheel steering amount. The basic auxiliary steering angle control amount to be given is determined accordingly.
一方、前後輪回転速度差検出手段eによる前後輪回転
速度差検出値とオフセット値設定手段gによる車速対応
オフセット設定値とに差が生じた場合には、修正補助舵
角制御量決定手段hにおいて、両値の然が増加するに従
ってオーバステア側に修正する修正補助舵角制御量が決
定される。On the other hand, if there is a difference between the front and rear wheel rotational speed difference detection means e and the vehicle speed corresponding offset set value by the offset value setting means g, the correction auxiliary steering angle control amount determining means h As the two values increase, the correction auxiliary steering angle control amount to be corrected to the oversteer side is determined.
そして、補助舵角制御量決定手段iでは、前記基本補
助舵角制御量と修正補助舵角制御量との和により補助舵
角制御量が決定され、出力手段jからは、決定した補助
舵角制御量が得られる駆動指令が補助転舵機構bに出力
される。In the auxiliary steering angle control amount determining means i, the auxiliary steering angle control amount is determined by the sum of the basic auxiliary steering angle control amount and the corrected auxiliary steering angle control amount, and the determined auxiliary steering angle is output from the output means j. A drive command for obtaining the control amount is output to the auxiliary steering mechanism b.
従って、低速スリップ旋回時においては、車速対応オ
フセット設定値が小さな値であり、この値を超える小さ
い前後輪回転速度差が発生した時点から補助転舵輪がオ
ーバステア側に舵角修正される為、ステア特性がオーバ
ステア方向に変化し、小回り旋回が可能となる。Accordingly, during low-speed slip turning, the vehicle speed corresponding offset setting value is a small value, and the steering wheel is corrected to the oversteer side from the time when a small difference between the front and rear wheel rotation speeds exceeding this value is generated. The characteristics change in the oversteer direction, and a small turn is enabled.
また、高速スリップ旋回時においては、車速対応オフ
セット設定値が大きな値であり、この値を超える大きな
前後輪回転速度差が発生しないことには、補助転舵輪が
オーバステア側に舵角修正されない為、オフセット設定
値を超えないスリップ発生域ではステア特性の変化が抑
えられ、高速旋回時の安定性が確保されるし、オフセッ
ト設定値を超えるスリップ発生域では駆動スリップによ
るコーナリングフォース低下を原因とする過大なドリフ
トアウトの発生が防止される。Also, at the time of high-speed slip turning, the vehicle speed corresponding offset setting value is a large value, and if a large difference in front and rear wheel rotation speed exceeding this value does not occur, the auxiliary steered wheels are not corrected to the oversteer side because the steering angle is not corrected. In the slip range where the offset does not exceed the set value, the change in the steering characteristics is suppressed, ensuring stability during high-speed turning.In the slip range exceeding the offset set value, excessive cornering caused by cornering force reduction due to drive slip is caused. Drift-out is prevented from occurring.
(実施例) 以下、本発明の指令を図面に基づいて説明する。(Examples) Hereinafter, instructions of the present invention will be described with reference to the drawings.
まず、構成を説明する。 First, the configuration will be described.
第2図は実施例の後輪舵角制御システム(補助舵角制
御装置)が適用された前輪駆動車の全体図で、システム
搭載の前輪駆動車は、ドライバーによるハンドル操作に
応じてエンジン駆動輪である前輪1,1を操舵するフロン
トステアリングユニット2(前輪操舵機構)と、前輪操
舵時に外部からの駆動指令に応じて非駆動輪である後輪
3,3に後輪舵角δr(補助舵角制御量)を与える油圧ア
クチュエータ4(補助転舵機構)とが設けられている。FIG. 2 is an overall view of a front wheel drive vehicle to which a rear wheel steering angle control system (auxiliary steering angle control device) according to the embodiment is applied. Front steering unit 2 (front wheel steering mechanism) for steering front wheels 1 and 1, and rear wheels that are non-drive wheels in response to an external drive command during front wheel steering.
A hydraulic actuator 4 (auxiliary steering mechanism) that provides the rear wheel steering angle δ r (auxiliary steering angle control amount) to 3, 3 is provided.
尚、前記油圧アクチュエータ4は、加圧作動油を供給
するオイルポンプ41と、油圧遮断時にはスプリングによ
る付勢力で後輪3,3を舵角中立位置に保持する油圧シリ
ンダ42と、前記オイルポンプ41と油圧シリンダ42とを連
結する油路43,44の途中に設けられた制御バルブ45と、
前記油圧シリンダ42のピストンストロークを後輪舵角δ
rに変換するステアリングリンケージ46,46を有して構
成されている。The hydraulic actuator 4 includes an oil pump 41 for supplying pressurized hydraulic oil, a hydraulic cylinder 42 for holding the rear wheels 3, 3 at a steering angle neutral position by a biasing force of a spring when the hydraulic pressure is cut off, and an oil pump 41. A control valve 45 provided in the middle of oil passages 43 and 44 connecting the hydraulic cylinder 42 and
The piston stroke of the hydraulic cylinder 42 is changed to the rear wheel steering angle δ.
It has steering linkages 46, 46 for converting into r .
前記制御バルブ45を作動制御する後輪舵角制御システ
ムは、必要情報を電気信号により検出するセンサとし
て、前輪操舵角θ(前輪操舵量)を検出する前輪操舵角
センサ5(前輪操舵量検出手段)と、前輪回転速度Nfを
検出する前輪回転速度センサ6と、後輪回転速度Nfを検
出する後輪回転速度センサ7と、車速Vを検出する車速
センサ8と、フィードバック情報として用いられる後輪
舵角δrをシリンダストロークにより検出する後輪舵角
センサ9とが設けられている。A rear wheel steering angle control system for controlling the operation of the control valve 45 includes a front wheel steering angle sensor 5 (front wheel steering amount detecting means) for detecting a front wheel steering angle θ (front wheel steering amount) as a sensor for detecting necessary information by an electric signal. and), a front wheel rotational speed sensor 6 for detecting a front wheel rotational speed N f, a wheel rotation speed sensor 7 after detecting a rear wheel rotational speed N f, a vehicle speed sensor 8 for detecting a vehicle speed V, used as feedback information A rear wheel steering angle sensor 9 for detecting a rear wheel steering angle δr based on a cylinder stroke is provided.
また、これらのセンサ5,6,7,8,9からの検出信号を入
力し、所定の演算処理により後輪舵角目標値δr *を求
めると共にこの後輪舵角目標値δr *が得られる出力信
号を制御バルブ45に印加する手段として、後輪舵角コン
トローラ10が設けられている。Further, inputs the detection signals from these sensors 5, 6, 7, 8, this rear wheel steering angle target value [delta] r * with determining the rear wheel steering angle target value [delta] r * by a predetermined calculation process As means for applying the obtained output signal to the control valve 45, a rear wheel steering angle controller 10 is provided.
そして、前記後輪舵角コントローラ10には、前後輪回
転速度差演算部(前後輪回転速度差検出手段)と、前輪
操舵角速度演算部と、前輪操舵角θに対する車速対応ゲ
インK1を設定する第1ゲイン設定部と、前輪操舵角速度
に対する車速対応ゲインK2を設定する第2ゲイン設定
部と、前後輪回転速度差ΔNのオフセット値を車速Vの
増大に従って大きな値に設定するオフセット値設定部
(オフセット値設定手段)と、K1,θ,K2,に応じて与
える基本後輪舵角δroを決定する基本後輪舵角決定部
(基本補助舵角制御量決定手段)と、前後輪回転速度差
ΔNと車速対応オフセット設定値NOFFとの差Nが増加す
るに従ってオーバステア側に修正する修正後輪舵角
δr′を決定する修正後輪舵角決定部(修正補助舵角制
御量決定手段)と、前記基本後輪舵角δroと修正後輪舵
角δr′との和により後輪舵角目標値δr *を決定する
後輪舵角目標値決定部(補助舵角制御量決定手段)と、
決定した後輪舵角目標値δr *が得られる駆動指令を制
御バルブ45に出力する出力部(出力手段)とが制御プロ
グラムとして組込まれている。Then, the rear wheel steering angle controller 10 sets the front and rear wheel rotational speed difference calculating section (front and rear wheel rotational speed difference detection means), a front wheel steering angular velocity calculating section, a vehicle speed corresponding gain K 1 for front-wheel steering angle θ a first gain setting unit, a front wheel and a second gain setting unit that sets a vehicle speed corresponding gain K 2 to the steering angular velocity, an offset value setting unit that sets a larger value to the offset value of the front and rear wheels rotational speed difference ΔN with increasing vehicle speed V (Offset value setting means), a basic rear wheel steering angle determining section (basic auxiliary steering angle control amount determining means) for determining a basic rear wheel steering angle δ ro given according to K 1 , θ, K 2 , A corrected wheel steering angle determination unit (corrected auxiliary steering angle control) that determines a corrected wheel steering angle δ r ′ to be corrected to oversteer as the difference N between the wheel rotation speed difference ΔN and the vehicle speed corresponding offset set value N OFF increases. Amount determining means) and the basic rear wheel steering angle δ wheel steering angle target value determiner after determining the rear wheel steering angle target value [delta] r * by the sum of the ro and modification rear wheel steering angle [delta] r 'and (the auxiliary steering angle control quantity determining means),
An output unit (output means) for outputting a drive command to obtain the determined rear wheel steering angle target value δ r * to the control valve 45 is incorporated as a control program.
次に、作用を説明する。 Next, the operation will be described.
第3図は後輪舵角コントローラ10で所定の制御時間を
周期として繰り返し行なわれる後輪舵角制御処理作動の
流れを示すフローチャートで、以下、各ステップについ
て述べる。FIG. 3 is a flowchart showing a flow of a rear wheel steering angle control process operation repeatedly performed by the rear wheel steering angle controller 10 with a predetermined control time as a cycle. Each step will be described below.
ステップ31では、車速V,前輪操舵角θ,前輪回転速度
Nf,後輪回転速度Nfが入力される。In step 31, the vehicle speed V, the front wheel steering angle θ, the front wheel rotation speed
N f and the rear wheel rotation speed N f are input.
ステップ32では、前後輪回転速度差ΔNが下記の式に
より演算される。In step 32, the front and rear wheel rotational speed difference ΔN is calculated by the following equation.
ΔN=Nf−Nr ステップ33では、前輪操舵角θを時間微分した単位時
間当たりの舵角変化量によ操舵角速度が演算される。In ΔN = N f -N r step 33, by the steering angle change per unit time obtained by differentiating the front wheel steering angle θ time steering angular speed is calculated.
θ0;1周期前のθ Δt:制御時間 ステップ34では、前輪操舵角θに対する車速対応ゲイ
ンK1が演算される。 theta 0; 1 cycle before theta Delta] t: the control time step 34, the vehicle speed corresponding gain K 1 for the front wheel steering angle theta is calculated.
尚、演算式は、K1=f1(V)であり、第4図に示すよ
うに、低車速域は逆相側にゲインK1が設定され、中速域
ではゲインK1がほぼ0に設定され、高速域では同相側に
ゲインK1が設定される。The arithmetic expression is K 1 = f 1 (V). As shown in FIG. 4, the gain K 1 is set to the opposite phase in the low vehicle speed range, and the gain K 1 is almost 0 in the middle speed range. It is set to the gain K 1 is set to the in-phase side in the high speed range.
即ち、低速小回り性と高速安定性を確保するようにゲ
インK1は設定される。That is, the gain K 1 to ensure low speed maneuverability and fast stability is set.
ステップ35では、前輪操舵角速度に対する車速対応
ゲインK2が演算される。In step 35, the vehicle speed-basis gain K 2 for the front wheel steering angular speed is calculated.
尚、演算式は、K2=f2(V)であり、第5図に示すよ
うに、低中車速域ではゲインK2が0に設定され、高速域
では逆相側にゲインK2が設定される。即ち、高速走行時
に旋回初期の車両回頭性を向上させるように設定され
る。The calculation formula is K 2 = f 2 (V) , as shown in FIG. 5, in the low middle speed range gain K 2 is set to 0, the gain K 2 in the opposite phase side in the high speed range Is set. That is, the setting is made so as to improve the turning performance of the vehicle at the beginning of a turn when traveling at high speed.
ステップ36では、前後輪回転速度差ΔNの車速対応オ
フセット設定値NOFFが演算される。In step 36, a vehicle speed corresponding offset set value N OFF of the front and rear wheel rotation speed difference ΔN is calculated.
尚、演算式は、NOFF=f3(V)であり、第6図に示す
ように、NOFFは車速Vの増大に従って徐々に大きな値に
設定される。The operation formula is N OFF = f 3 (V), and N OFF is gradually set to a larger value as the vehicle speed V increases, as shown in FIG.
ステップ37では、後輪舵角目標値δr *が、δrZ*=
f4(K1,θ,K2,θ,ΔN,NOFF)の式により演算される。In step 37, the rear wheel steering angle target value [delta] r * is, [delta] r Z * =
It is calculated by the formula of f 4 (K 1 , θ, K 2 , θ, ΔN, N OFF ).
この後輪舵角目標値δr *は、基本後輪舵角δroと修
正後輪舵角δr′との和による塩山で求められるもの
で、基本後輪舵角δroは、下記の式で与えられる。Rear wheel steering angle target value [delta] r * this, those obtained by Enzan by the sum of the base rear-wheel steering angle [delta] ro the corrected wheel steering angle [delta] r ', the base rear-wheel steering angle [delta] ro, the following Given by the formula.
δro=K1*θ+K2* また、前後輪回転速度差ΔNの絶対値|ΔN|と車速対
応オフセット設定値NOFFの絶対値|NOFF|との差Nが増加
するに従って逆相側(オーバステア側)に修正する修正
後輪舵角δr′は、下記の式で与えられる。 δ ro = K 1 * θ + K 2 * , and the absolute value of the front and rear wheel rotational speed difference .DELTA.N | .DELTA.N | and the vehicle speed corresponding offset setting value N absolute value of the OFF | N OFF | opposite phase side according to the difference N increases the ( The corrected wheel steering angle δ r ′ to be corrected to the oversteer side is given by the following equation.
δr′=−K3*N 但し、N=MAX(|ΔN|−|NOFF|,0) K3は比例定数 であり、K3*Nを特性図としてあわらすと、第7図に示
す特性となり、K3*N>0は同相方向を示し、修正後輪
舵角δr′はこれにマイナスが付けられることで逆相方
向の値となる。δ r ′ = −K 3 * N where N = MAX (| ΔN | − | N OFF |, 0) K 3 is a proportionality constant, and when K 3 * N is shown as a characteristic diagram, FIG. K 3 * N> 0 indicates the in-phase direction, and the corrected wheel steering angle δ r ′ becomes a value in the opposite phase direction by adding a minus to this.
尚、|ΔN|及び|NOFF|としているのは、アクレル踏み
込み等による駆動力過剰で前輪1,1が過回転している加
速スリップの時も、アクセル足離し等による減速により
前輪1,1がロック傾向にある減速スリップの時も共に駆
動スリップに含めて制御するためである。Note that | ΔN | and | N OFF | mean that the front wheels 1,1 are also decelerated by decelerating the accelerator pedals, etc., even when the front wheels 1,1 are excessively rotating due to excessive driving force due to depression of the accelerator. Is also included in the drive slip when performing a deceleration slip that tends to lock.
ステップ38では、ステップ37で求められた後輪舵角目
標値δr *が得られる出力信号が制御バルブ45に印加さ
れる。In step 38, the output signal-wheel steering angle target value [delta] r * is obtained after being calculated in step 37 is applied to the control valve 45.
次に、グリップ旋回時とスリップ旋回時とに分けて作
用を述べる。Next, the operation will be described separately for grip turning and slip turning.
(イ)グリップ旋回時 定速旋回時やレーンチェンジ時等のグリップ旋回時に
は、通常、駆動クリップをあらわす前後輪回転速度差Δ
Nが車速対応オフセット設定値NOFFに達せず、修正後輪
舵角δr′は0となり、後輪舵角目標値δr *は、基本
後輪舵角δroのみにより下記の式で与えられる。(A) When turning the grip When turning the grip, such as when turning at a constant speed or when changing lanes, the difference between the rotational speeds of the front and rear wheels, usually representing the drive clip, Δ
N does not reach the vehicle speed corresponding offset set value N OFF , the corrected rear wheel steering angle δ r ′ becomes 0, and the rear wheel steering angle target value δ r * is given by the following equation using only the basic rear wheel steering angle δ ro. Can be
δr *=K1*θ+K2* …… 従って、低速旋回時には、第4図に示すゲインK1の特
性により、後輪3,3が逆相に転舵される為、低速小回り
性が得られる。 δ r * = K 1 * θ + K 2 * ...... Therefore, during low speed turning, the characteristic of the gain K 1 shown in FIG. 4, since the rear wheels 3 are steered in opposite phase, the low-speed maneuverability properties obtained Can be
また、高速旋回時には、旋回初期にハンドルに切り込
み操作を行なうと、第5図に示すゲインK2の特性により
瞬間的に逆相に後輪3,3が転舵される為、旋回初期の車
両回頭性が向上するし、その後、保舵状態にすると、第
4図に示すゲインK1の特性により、後輪3,3が前輪1,1に
対して同相に転舵される為、高速安定性が確保される。Further, at the time of high speed turning, when the operation incision in the handle pivot initial, since the rear wheels 3 are steered momentarily reversed phase the characteristics of the gain K 2 shown in FIG. 5, turning the initial vehicle When the turning performance is improved and the steering is maintained, the rear wheels 3, 3 are steered in phase with respect to the front wheels 1, 1 by the characteristic of the gain K1 shown in FIG. Nature is secured.
(ロ)スリップ旋回時 加減速操作を伴なう旋回時やタイトコーナ旋回時等の
スリップ旋回時であって、駆動スリップをあらわす前後
輪回転速度差ΔNが車速対応オフセット設定値NOFFに達
しない領域では上記で示す式に基づいて後輪舵角目標
値δr *が与えられるが、前後輪回転速度差ΔNが車速
対応オフセット設定値NOFFを超える領域では、後輪舵角
目標値δr *は、基本後輪舵角δroが修正後輪舵角
δr′により逆相方向に修正された値、つまり、下記の
式で与えられる。(B) Slip turning An area where the difference between the front and rear wheel rotation speeds ΔN representing the driving slip does not reach the vehicle speed corresponding offset setting value N OFF during a slip turning such as a turning accompanied by an acceleration / deceleration operation or a tight corner turning. in Although the rear wheel steering angle target value [delta] r * is given based on the equation shown above, in a region where the front and rear wheel rotational speed difference ΔN is greater than the vehicle speed corresponding offset setting value N OFF, the rear wheel steering angle target value [delta] r * Is a value obtained by correcting the basic rear wheel steering angle δ ro in the opposite phase direction by the corrected rear wheel steering angle δ r ′, that is, given by the following equation.
δr *=δro+δr′ =K1*θ+K2*−K3*(|ΔN|−|NOFF|) …… (低速スリップ旋回時) 低速スリップ旋回時においては、第6図のオフセット
設定値特性に示すように、NOFFの値がN0または−N2の小
さな値であり、この値を超える小さい前後輪回転速度差
ΔNが発生した時点から後輪3,3が逆相側に修正される
為、ステア特性がオーバステア側となり小回り旋回が可
能となる。 δ r * = δ ro + δ r '= K 1 * θ + K 2 * -K 3 * (| ΔN | - | N OFF |) ...... during (low speed slip turning) slow slip turning offset of Figure 6 As shown in the set value characteristics, the value of N OFF is a small value of N 0 or −N 2 , and the rear wheels 3, 3 are in the opposite phase from the time when a small front and rear wheel rotational speed difference ΔN exceeding this value occurs. , The steer characteristic becomes the oversteer side, and a small turn is possible.
例えば、30km/h以下程度のタイトコーナ旋回時には、
前後輪の旋回奇跡差によ前輪回転速度Nfが後輪回転速度
Nrよりも速くなり、オフセット値NOFFの値を超える前後
輪回転速度差ΔNが発生するが、この時、後輪3,3が逆
相側に修正される為、アンダーステアによる旋回の膨ら
みが防止されて小回り旋回が可能となる。For example, when turning around a tight corner at about 30 km / h or less,
The front wheel rotation speed N f is changed to the rear wheel rotation speed due to the difference in turning miracle between the front and rear wheels.
Faster than N r, although the front and rear wheel rotational speed difference ΔN exceeds the value of the offset value N OFF is generated, this time, since the rear wheels 3 is corrected in the opposite phase side, the bulging of the swivel according to understeer This makes it possible to make a small turn.
また、前輪操舵量に応じて同相に後輪転舵角を与える
制御を行なう四輪操舵車と比べた場合には、コーナーラ
インのトレース性が増す。Further, as compared with a four-wheel steering vehicle that performs control to give a rear wheel turning angle to the same phase according to the front wheel steering amount, traceability of a corner line is improved.
即ち、コーナーの旋回加速立上がり時等で前輪加速ス
リップが発生した時や氷雪路等の低摩擦係数路のコーナ
ー進入時等においてアクセルOFF操作により前輪減速ス
リップが発生した時には、加減速スリップによりフロン
トのコーナリングフォースが減少する為、ハンドルを切
り増す操作が行なわれる。しかし、後輪同相制御の場合
には前輪操舵量を増すとより同相側へ舵角修正されるこ
とでよりアンダーステア傾向が強くなり、狙い通りのラ
インを旋回できない。That is, when the front wheel deceleration slip occurs due to the accelerator OFF operation when the front wheel acceleration slip occurs at the time of turning acceleration of a corner or when entering a corner on a low friction coefficient road such as an icy road, acceleration / deceleration slip causes the front wheel to slip. In order to reduce the cornering force, an operation of turning the steering wheel more is performed. However, in the case of the rear-wheel in-phase control, when the front wheel steering amount is increased, the steering angle is corrected to the in-phase side, so that the understeer tendency becomes stronger, so that the line cannot be turned as intended.
これに対し、本制御では、加減速スリップ量が大きい
時には後輪が逆相側に大きく修正される為、この逆相修
正によるオーバモーメントで狙い通りのラインを旋回す
ることができる。On the other hand, in the present control, when the acceleration / deceleration slip amount is large, the rear wheels are largely corrected to the opposite phase side, so that the desired line can be turned by the over-moment due to the opposite phase correction.
(高速スリップ旋回時) 高速スリップ旋回時においては、第6図のオフセット
設定値特性に示すように、NOFFの値がN1または−N3の大
きな値であり、この値を超える大きな前後輪回転速度差
ΔNが発生しないことには、後輪3,3が逆相側に修正さ
れることがない為、NOFFの値を超えるまでは上記の式
に基づく高速グリップ旋回時の後輪同相制御が維持さ
れ、高速旋回時の安定性が確保される。In (fast when slipping turn) at high slip turning, as shown in the offset setting value characteristic of FIG. 6, the value of N OFF is of a large value of N 1 or -N 3, a large front and rear wheels to exceed this value The fact that the rotation speed difference ΔN does not occur means that the rear wheels 3, 3 are not corrected to the opposite phase, so the rear wheel in-phase during high-speed grip turning based on the above equation until the value exceeds N OFF Control is maintained, and stability during high-speed turning is ensured.
即ち、一般のフロントヘビーの前輪駆動車では、前述
タイヤ動半径のうち前側タイヤ径が輪荷重で小さくな
り、駆動スリップ量の検出値が真の駆動スリップ量に比
べて大きな値として誤検出する事が考え得る。その時、
高速旋回時に同相側の基本後輪舵角より前記駆動スリッ
プ量の検出値に基づいた逆相側の修正後輪舵角が大きく
なってしまった場合には、旋回走行に伴なう加減速スリ
ップにより前輪のコーナリングフォースが低下している
のに加えて、車両にオーバモーメントが作用することに
なり、車両スピンに至ってしまうが、オフセット値NOFF
を越える前後輪回転速度差ΔNが発生しない限り前記後
輪の逆相側への修正を中止する為、該修正による車両ス
ピンが防止できる。That is, in a general front heavy front-wheel drive vehicle, the front tire diameter of the above-described tire dynamic radius becomes smaller due to the wheel load, and the detection value of the drive slip amount is erroneously detected as a larger value than the true drive slip amount. Can be considered. At that time,
If the corrected rear wheel steering angle on the opposite phase based on the detected value of the drive slip amount becomes larger than the basic rear wheel steering angle on the same phase during high-speed turning, acceleration / deceleration slip accompanying turning In addition to this, the cornering force of the front wheels is reduced, and in addition, an over-moment acts on the vehicle, leading to vehicle spin, but the offset value N OFF
Unless a front-rear wheel rotation speed difference ΔN exceeding ΔN occurs, the correction of the rear wheels to the opposite phase is stopped, so that the vehicle spin due to the correction can be prevented.
また、NOFFの値を超える大きな前後輪回転速度差ΔN
が発生すると、上記の式に基づいて後輪舵角目標値δ
r *が与えられることで、後輪3,3の逆相修正が加えら
れ、過大なドリフトアウトの発生は防止される。In addition, a large front and rear wheel rotational speed difference ΔN exceeding the value of N OFF
Occurs, the rear wheel steering angle target value δ is calculated based on the above equation.
By giving r *, a reverse phase correction of the rear wheels 3, 3 is added, and occurrence of excessive drift out is prevented.
即ち、前輪に大きなスリップ量が発生し、前輪のコー
ナリングフォースが大幅に低下しているにもかかわら
ず、同相の後輪舵角を与えた状態のままとしておくと、
過大なドリフトアウトが発生してしまうことになるが、
その時に限り後輪を逆相修正する事で、前記過大なドリ
フトアウトは防止される。That is, despite the fact that a large amount of slip occurs on the front wheels and the cornering force of the front wheels has been greatly reduced, if the same-phase rear wheel steering angle is given,
Excessive drift out will occur,
Excessive drift-out is prevented by correcting the rear wheels in reverse phase only at that time.
つまり、高速旋回時には、前後輪回転速度差ΔNに対
する舵角修正不感帯を大きく設定することにより、過大
なドリフトアウト防止と安定性確保とを両立する制御と
している。That is, at the time of high-speed turning, by setting a large steering angle correction dead zone for the front and rear wheel rotation speed difference ΔN, control is performed to prevent both excessive drift out and ensure stability.
また、舵角修正不感帯の設定により前後輪回転速度差
ΔNの検出誤差もその大半が吸収され、舵角制御に与え
る影響が非常に小さく抑えられることになり、前後輪回
転速度差ΔNの検出値を、旋回半径やタイヤ径等により
補正する演算処理等を要しない。Also, by setting the steering angle correction dead zone, most of the detection error of the front and rear wheel rotation speed difference ΔN is absorbed, and the influence on the steering angle control is suppressed to a very small value. Does not need to be subjected to a calculation process or the like that corrects the turning angle based on the turning radius, the tire diameter, and the like.
以上、実施例を図面に基づいて説明してきたが、具体
的な構成はこの実施例に限られるものではない。Although the embodiments have been described with reference to the drawings, the specific configuration is not limited to the embodiments.
例えば、実施例では駆動スリップ時に後輪のみを逆相
修正する後輪舵角制御システムの例を示したが、前後輪
を共に補助転舵するシステムにも適用できるし、また、
前輪のみを補助転舵するシステムにも適用できる。尚、
前輪を補助転舵するものにおいては、駆動スリップ時に
オーバモーメントを増すべく前輪を同相修正することに
なる。For example, in the embodiment, the example of the rear wheel steering angle control system in which only the rear wheels are subjected to the reverse phase correction at the time of the driving slip has been described.
The present invention can also be applied to a system in which only the front wheels are turned. still,
In the case where the front wheels are steered, the front wheels are in-phase corrected so as to increase the over-moment during a drive slip.
(発明の効果) 以上説明してきたように、本発明にあっては、前輪操
舵時に前輪または後輪の少なくとも一方を補助転舵する
前輪駆動車用補助舵角制御装置において、前後輪回転速
度差のオフセット値を、低速時はオーバステア側に転舵
修正され易い小さな値に設定し、車速の増大に従って次
第に大きくなる値により設定し、高速時はオーバステア
側に舵角修正されにくい大きな値に設定し、前後輪回転
速度差により検出した駆動スリップ量と車速対応オフセ
ット設定値との差によりドリフト防止の補助舵角制御を
行なう手段とした為、課題なドリフトアウトの発生を防
止しながら、低速旋回時における小回り性の確保と、高
速旋回時における安定性の確保とを達成することが出来
るという効果が得られる。(Effects of the Invention) As described above, according to the present invention, in a front-wheel drive vehicle auxiliary steering angle control device that performs auxiliary steering of at least one of a front wheel and a rear wheel during front-wheel steering, a front-rear wheel rotational speed difference is provided. The offset value is set to a small value at which the steering is easily corrected to the oversteer side at low speed, and is set to a value that gradually increases as the vehicle speed increases, and is set to a large value at which the steering angle is hardly corrected to the oversteer side at high speed. Means for performing auxiliary steering angle control for drift prevention based on the difference between the drive slip amount detected from the front and rear wheel rotational speed difference and the vehicle speed corresponding offset setting value. In this case, it is possible to achieve the effect of ensuring the small turning performance and the stability during high-speed turning.
第1図は本発明の前輪駆動車用補助舵角制御装置を示す
クレーム対応図、第2図は実施例の後輪舵角制御システ
ムが適用された前輪駆動車を示す全体図、第3図は実施
例システムの後輪舵角コントローラでの後輪舵角演算処
理作動の流れを示すフローチャート、第4図は前輪舵角
の車速対応ゲイン特性図、第5図は前輪操舵角速度の車
速対応ゲイン特性図、第6図は車速対応オフセット設定
値特性図、第7図は修正後輪舵角特性図である。 a……前輪操舵機構 b……補助転舵機構 c……前輪操舵量検出手段 d……基本補助舵角制御量決定手段 e……前後輪回転速度差検出手段 f……車速検出手段 g……オフセット値設定手段 h……修正補助舵角制御量決定手段 i……補助舵角制御量決定手段 j……出力手段FIG. 1 is a claim correspondence diagram showing an auxiliary steering angle control device for a front wheel drive vehicle of the present invention, FIG. 2 is an overall view showing a front wheel drive vehicle to which a rear wheel steering angle control system according to an embodiment is applied, FIG. Is a flowchart showing a flow of a rear wheel steering angle calculation processing operation in a rear wheel steering angle controller of the embodiment system, FIG. 4 is a gain characteristic diagram of a front wheel steering angle corresponding to a vehicle speed, and FIG. 5 is a vehicle speed corresponding gain of a front wheel steering angular velocity. FIG. 6 is a characteristic diagram of the offset set value corresponding to the vehicle speed, and FIG. 7 is a characteristic diagram of the corrected wheel steering angle. a front wheel steering mechanism b auxiliary steering mechanism c front wheel steering amount detection means d basic auxiliary steering angle control amount determination means e front and rear wheel rotational speed difference detection means f vehicle speed detection means g ... Offset value setting means h ... Correction auxiliary steering angle control amount determination means i ... Auxiliary steering angle control amount determination means j ... Output means
Claims (1)
ドライバーによるハンドル操作に応じて前輪を操舵する
前輪操舵機構と、 外部からの駆動指令に応じて前輪または後輪の少なくと
も一方に補助舵角制御量を与える補助転舵機構と、 前輪操舵量を検出する前輪操舵量検出手段と、 前輪操舵量に応じて与える基本補助舵角制御量を決定す
る基本補助舵角制御量決定手段と、 前輪回転速度と後輪回転速度との差を検出する前後輪回
転速度差検出手段と、 車速を検出する車速検出手段と、 前後輪回転速度差のオフセット値を、低速時はオーバス
テア側に舵角修正され易い小さな値に設定し、車速の増
大に従って次第に大きくなる値により設定し、高速時は
オーバステア側に舵角修正されにくい大きな値に設定す
るオフセット値設定手段と、 前後輪回転速度差検出値と車速対応オフセット設定値と
の差が増加するに従ってオーバステア側に修正する修正
補助舵角制御量を決定する修正補助舵角制御量決定手段
と、 前記基本補助舵角制御量と修正補助舵角制御量との和に
より補助舵角制御量を決定する補助舵角制御量決定手段
と、 決定した補助舵角制御量が得られる駆動指令を前記補助
転舵機構に出力する出力手段と、 を備えていることを特徴とする前輪駆動車用補助舵角制
御装置。1. A front wheel drive vehicle having front wheels as drive wheels,
A front wheel steering mechanism that steers the front wheels according to the steering wheel operation by the driver, an auxiliary steering mechanism that applies an auxiliary steering angle control amount to at least one of the front wheels or the rear wheels in response to an external drive command, and detects the front wheel steering amount Front wheel steering amount detecting means, basic auxiliary steering angle control amount determining means for determining a basic auxiliary steering angle control amount to be given according to the front wheel steering amount, and front and rear wheels for detecting a difference between the front wheel rotation speed and the rear wheel rotation speed. The rotational speed difference detecting means, the vehicle speed detecting means for detecting the vehicle speed, and the offset value of the front and rear wheel rotational speed difference is set to a small value at which the steering angle is easily corrected to the oversteer side at low speed, and gradually increases as the vehicle speed increases. Offset value setting means that sets a large value that is difficult to correct the steering angle to the oversteer side at high speed, and a front and rear wheel rotational speed difference detection value and a vehicle speed corresponding offset setting value. Correction auxiliary steering angle control amount determining means for determining a correction auxiliary steering angle control amount to be corrected to the oversteer side as the difference in the steering angle increases, and assist steering by a sum of the basic auxiliary steering angle control amount and the correction auxiliary steering angle control amount. Front wheel, comprising: an auxiliary steering angle control amount determining unit that determines an angle control amount; and an output unit that outputs a drive command for obtaining the determined auxiliary steering angle control amount to the auxiliary steering mechanism. Auxiliary steering angle control device for driving vehicles.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1273190A JP2699585B2 (en) | 1989-10-20 | 1989-10-20 | Auxiliary steering angle control device for front wheel drive vehicles |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1273190A JP2699585B2 (en) | 1989-10-20 | 1989-10-20 | Auxiliary steering angle control device for front wheel drive vehicles |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH03135874A JPH03135874A (en) | 1991-06-10 |
JP2699585B2 true JP2699585B2 (en) | 1998-01-19 |
Family
ID=17524355
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1273190A Expired - Lifetime JP2699585B2 (en) | 1989-10-20 | 1989-10-20 | Auxiliary steering angle control device for front wheel drive vehicles |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2699585B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5119306B2 (en) * | 2010-09-22 | 2013-01-16 | トヨタ自動車株式会社 | Vehicle travel control device |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6271761A (en) * | 1985-09-25 | 1987-04-02 | Toyota Motor Corp | Rear-wheel steering controller for four-wheel steering vehicle |
JP2707551B2 (en) * | 1987-08-25 | 1998-01-28 | 株式会社デンソー | Vehicle propulsion control device |
-
1989
- 1989-10-20 JP JP1273190A patent/JP2699585B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPH03135874A (en) | 1991-06-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4003627B2 (en) | Steering control device for vehicle | |
US6931313B2 (en) | Vehicular steering device | |
JPH10138785A (en) | Yaw moment control device for vehicle | |
JPH0392483A (en) | Rear wheel steering control device | |
JPH01309879A (en) | Control method for steering rear wheel of automobile | |
JPH05155349A (en) | Rear wheel steering control method of vehicle | |
JP3590608B2 (en) | Vehicle turning control device and steering limit determination method | |
JP2000118429A (en) | Rear wheel steering device for rear wheel drive vehicle | |
JP2699585B2 (en) | Auxiliary steering angle control device for front wheel drive vehicles | |
JP2707574B2 (en) | Vehicle turning control device | |
JP2011126334A (en) | Turning behavior control device of vehicle | |
JP7348262B2 (en) | Step-by-step detection of the appearance of torque steer | |
JP3019466B2 (en) | Road friction coefficient detector | |
JP2018161943A (en) | Vehicle deceleration-time posture control device | |
JPS62238171A (en) | Four wheel steering device for vehicle | |
JPH0640051B2 (en) | Road condition determination device | |
JPS6212471A (en) | Four-wheel steering device for car | |
JP2746002B2 (en) | Driving force distribution device for four-wheel drive vehicle with four-wheel steering device | |
JPH01262264A (en) | Four-wheel steering control device of vehicle with differential limiting device | |
JP3132695B2 (en) | Vehicle yawing momentum control device | |
KR20190034831A (en) | Rear wheel steering apparatus of vehicle and control method thereof | |
JPH05185859A (en) | Control device of driving system clutch for vehicle | |
JPH072130A (en) | Method for controlling rear wheel steering device | |
JP2553702Y2 (en) | Power steering device | |
JP3076429B2 (en) | Vehicle rear wheel steering system |