JPH06127405A - Detecting method for friction coefficient of road surface - Google Patents
Detecting method for friction coefficient of road surfaceInfo
- Publication number
- JPH06127405A JPH06127405A JP28173292A JP28173292A JPH06127405A JP H06127405 A JPH06127405 A JP H06127405A JP 28173292 A JP28173292 A JP 28173292A JP 28173292 A JP28173292 A JP 28173292A JP H06127405 A JPH06127405 A JP H06127405A
- Authority
- JP
- Japan
- Prior art keywords
- friction coefficient
- road surface
- vehicle
- slip
- lateral acceleration
- 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.)
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- Steering Control In Accordance With Driving Conditions (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、自動車のタイヤと路面
の間の摩擦係数を検出する方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a friction coefficient between a tire of an automobile and a road surface.
【０００２】[0002]
【従来の技術】従来、特開平１−１０１４３４号公報、
特開平１−１０１４３６号公報に開示されるように、車
両諸元とハンドル角と運動状態を表す値（車速、横加速
度）と運動方程式に基づいて、路面摩擦係数を演算し検
出するものがある。2. Description of the Related Art Conventionally, Japanese Unexamined Patent Publication No. 1-101434,
As disclosed in JP-A-1-101436, there is one that calculates and detects a road surface friction coefficient on the basis of vehicle specifications, a steering wheel angle, a value (vehicle speed, lateral acceleration) representing a motion state, and a motion equation. .
【０００３】[0003]
【発明が解決しようとする課題】この従来の方法による
と、本来均一路面では一定な筈の路面摩擦係数が、車両
の運動状態に応じて時々刻々変動するものとして検出さ
れるという問題点が生じる。本発明は、摩擦係数の本来
の定義により摩擦係数を検出し、精度の良い摩擦係数検
出を行うことを目的とする。According to this conventional method, there arises a problem that a road surface friction coefficient, which should be constant on an originally uniform road surface, is detected as a momentary fluctuation depending on the motion state of the vehicle. . It is an object of the present invention to detect a friction coefficient according to the original definition of the friction coefficient and to detect the friction coefficient with high accuracy.
【０００４】[0004]
【課題を解決するための手段】本発明は上記目的を達成
するため、車両がスリップした状態を検知し、検知直前
と検知中の車両に発生している加速度より路面の摩擦係
数を検出する。In order to achieve the above object, the present invention detects a slipping state of a vehicle and detects a friction coefficient of a road surface from accelerations occurring immediately before and during the detection.
【０００５】[0005]
【作用】車両がスリップした状態での加速度が路面摩擦
係数であるから、上記手段により本来の定義の摩擦係数
が検出できる。Since the acceleration when the vehicle is slipping is the road surface friction coefficient, the originally defined friction coefficient can be detected by the above means.
【０００６】[0006]
【実施例】本発明の摩擦係数検出方法の実施例を、図
１、図２を用いて説明する。始めに、スリップ判定の具
体的方法について説明をする。ハンドル角、車速、後輪
舵角、車両諸元（定数）とに基づいてヨーレート、横加
速度を計算する。これらは規範ヨーレート、規範横加速
度と呼ばれ、グリップ走行時に本来発生するヨーレー
ト、横加速度を表す。EXAMPLE An example of the friction coefficient detecting method of the present invention will be described with reference to FIGS. First, a specific method of slip determination will be described. The yaw rate and lateral acceleration are calculated based on the steering wheel angle, the vehicle speed, the rear wheel steering angle, and the vehicle specifications (constants). These are called the standard yaw rate and the standard lateral acceleration, and represent the yaw rate and the lateral acceleration that originally occur during grip traveling.
【０００７】規範ヨーレートおよび規範横加速度の具体
的計算方法を説明すると、ハンドル操舵時の車両運動を
モデル化した２輪モデルの運動方程式は、次の〔数１〕
〜〔数４〕で与えられる。A specific method of calculating the standard yaw rate and the standard lateral acceleration will be described. The motion equation of the two-wheel model that models the vehicle motion during steering of the steering wheel is as follows.
~ Is given by [Equation 4].
【０００８】[0008]
【数１】 [Equation 1]
【０００９】[0009]
【数２】 [Equation 2]
【００１０】[0010]
【数３】 [Equation 3]
【００１１】[0011]
【数４】 [Equation 4]
【００１２】上記〔数１〕〜〔数４〕について、入力を
ハンドル角、出力をヨーレート、横加速度とする伝達関
数でそれぞれ表現すると、次の〔数５〕〔数６〕のとお
りである。In the above [Equation 1] to [Equation 4], the following equations (5) and (6) are used to represent the transfer function with the steering wheel angle as the input and the yaw rate and the lateral acceleration as the outputs.
【００１３】[0013]
【数５】 [Equation 5]
【００１４】[0014]
【数６】 [Equation 6]
【００１５】車両諸元からＭ，ａ，ｂ，ＩZ を、またド
ライアスファルト路でグリップ走行した時のハンドル
角、車速、後輪舵角、ヨーレート、横加速度データに基
づいてＣf ，Ｃr をある定数に決めた上で〔数５〕〔数
６〕の値をハンドル角と車速に応じて計算するとグリッ
プ走行であれば、車両に発生すべき規範ヨーレート、規
範横加速度が求まる。なお、前記Ｃf ，Ｃr は、ドライ
アスファルト路でグリップ走行した時の、ハンドル角、
車速、後輪舵角、ヨーレート、横加速度のデータに基づ
いてある値に決めたものである。この計算をソフトウェ
アにより実現するために〔数５〕〔数６〕を状態表現
し、双一次変換を用いてハンドル角と車速信号のサンプ
リング周期に応じた離散化、漸化式化の手段をとってい
る。Based on vehicle specifications, M, a, b, I Z , and C f , C r based on steering wheel angle, vehicle speed, rear wheel steering angle, yaw rate, lateral acceleration data when grip traveling on a dry asphalt road. When the values of [Equation 5] and [Equation 6] are calculated according to the steering wheel angle and the vehicle speed after determining a certain constant, the standard yaw rate and the standard lateral acceleration to be generated in the vehicle can be obtained in the case of grip traveling. The C f and C r are steering wheel angles when grip traveling on a dry asphalt road,
It is set to a certain value based on the data of the vehicle speed, the rear wheel steering angle, the yaw rate, and the lateral acceleration. In order to realize this calculation by software, [Equation 5] and [Equation 6] are expressed as states, and a means for discretization and recurrence formulation is taken according to the steering angle and the sampling period of the vehicle speed signal using bilinear transformation. ing.
【００１６】次に、スリップ判定は、これら規範ヨーレ
ート、規範横加速度と、実際にセンサから得た実ヨーレ
ート、実横加速度の値との差をとり、次の３つの条件が
同時に成立し、この成立状態が１００ミリ秒以上に渡っ
て継続した時にスリップが発生したと判定される。 （１） 実ヨーレート−規範ヨーレートの値が正または
負の方向に連続して大きくなっていった。 （２） 実ヨーレート−規範ヨーレートの絶対値がある
値以上となった。 （３） 実横加速度−規範横加速度の絶対値がある値以
上となった。 これら各条件は、車両がドリフト、スピン状態あるいは
完全にコントロールを失った状態で発生する車両挙動を
実ヨーレート、実横加速度と規範ヨーレート、規範横加
速度を用いて説明したものである。Next, in the slip determination, the difference between these standard yaw rate and standard lateral acceleration and the values of the actual yaw rate and the actual lateral acceleration actually obtained from the sensor is taken, and the following three conditions are satisfied at the same time. When the established state continues for 100 milliseconds or more, it is determined that slip has occurred. (1) The value of the actual yaw rate minus the standard yaw rate continuously increased in the positive or negative direction. (2) The absolute value of the actual yaw rate-the standard yaw rate is above a certain value. (3) Absolute value of actual lateral acceleration-normative lateral acceleration exceeds a certain value. Each of these conditions describes the vehicle behavior that occurs when the vehicle drifts, spins, or completely loses control, using the actual yaw rate, the actual lateral acceleration, the reference yaw rate, and the reference lateral acceleration.
【００１７】次に、スリップ判定がなされた状態での加
速度が路面摩擦係数であるから、横加速度および前後加
速度を次の〔数７〕により計算して路面摩擦係数μを得
る。Next, since the acceleration in the state where the slip determination is made is the road surface friction coefficient, the lateral acceleration and the longitudinal acceleration are calculated by the following [Equation 7] to obtain the road surface friction coefficient μ.
【００１８】[0018]
【数７】 [Equation 7]
【００１９】具体的実施装置を図１を用いて説明する。
１は規範運動状態演算手段であり、ハンドル角検出手段
２からの信号と、後輪舵角検出手段３からの信号と、車
速検出手段４からの信号が入力される。また、演算手段
１は、定数Ｍ（車重），ａ（前軸から車両重心点までの
距離），ｂ（後軸から車両重心点までの距離），ｌ（ホ
イールベース長），Ｉz （ヨー慣性モーメント）と変数
Ｃf ，Ｃr を記憶部に記憶している。A concrete implementation device will be described with reference to FIG.
Reference numeral 1 is a reference motion state calculating means, to which a signal from the steering wheel angle detecting means 2, a signal from the rear wheel steering angle detecting means 3 and a signal from the vehicle speed detecting means 4 are input. Further, the calculation means 1 has constants M (vehicle weight), a (distance from front axis to vehicle center of gravity), b (distance from rear axle to vehicle center of gravity), l (wheelbase length), I z ( The yaw moment of inertia) and variables C f and C r are stored in the storage unit.
【００２０】演算手段１は、これらの値から線形の伝達
関数に基づいて、前記〔数５〕〔数６〕により車両に発
生すべき規範ヨーレートおよび規範横加速度を時々刻々
演算し、規範ヨーレートおよび規範横加速度をスリップ
検出手段８へ出力する。スリップ検出手段８では、ヨー
レート検出手段５からの信号と規範ヨーレートとの差お
よび横加速度検出手段６からの信号と規範横加速度との
差をとり、その差に基づいて前記のスリップ判定を行
い、スリップ判定信号を路面摩擦係数演算手段９へ出力
をだす。The computing means 1 momentarily computes the standard yaw rate and the standard lateral acceleration to be generated in the vehicle by the above-mentioned [Equation 5] and [Equation 6] on the basis of the linear transfer function, and the reference yaw rate and The reference lateral acceleration is output to the slip detecting means 8. The slip detecting means 8 takes the difference between the signal from the yaw rate detecting means 5 and the standard yaw rate and the difference between the signal from the lateral acceleration detecting means 6 and the standard lateral acceleration, and performs the slip determination based on the difference. The slip determination signal is output to the road surface friction coefficient calculation means 9.
【００２１】路面摩擦係数演算手段９では、横加速度検
出手段６と前後加速度検出手段７からの信号に基づい
て、常に前記〔数７〕の横加速度の２乗と前後加速度の
２乗の和の平方根を計算しており、スリップ検出手段８
からスリップ判定信号が出されたら、スリップ検出中の
値を路面の動摩擦係数、スリップ検出直前の値を静摩擦
係数とする。なお、前後加速度の検出にはセンサにより
方法と車速信号の微分もしくは差分に基づく方法があ
る。In the road surface friction coefficient calculating means 9, based on the signals from the lateral acceleration detecting means 6 and the longitudinal acceleration detecting means 7, the sum of the square of the lateral acceleration and the square of the longitudinal acceleration of [Equation 7] is always calculated. The square root is calculated, and the slip detection means 8
When the slip determination signal is output from, the value during the slip detection is the dynamic friction coefficient of the road surface, and the value immediately before the slip detection is the static friction coefficient. There are a method for detecting the longitudinal acceleration by a sensor and a method based on the differentiation or difference of the vehicle speed signal.
【００２２】次に、この摩擦係数検出手順についての基
本フローを図２に基づいて説明する。ステップ２１にお
いて、規範運動状態演算手段１に、ハンドル角検出手段
２からの信号、後輪舵角検出手段からの信号および、車
速検出手段からの信号を読み込む。Next, a basic flow of the friction coefficient detecting procedure will be described with reference to FIG. In step 21, the reference motion state calculating means 1 reads the signal from the steering wheel angle detecting means 2, the signal from the rear wheel steering angle detecting means, and the signal from the vehicle speed detecting means.
【００２３】ステップ２２において、演算手段１は、ス
テップ２１により得られた各信号の値と、記憶部に記憶
していた定数Ｍ（車重），ａ（前軸から車両重心点まで
の距離），ｂ（後軸から車両重心点までの距離），ｌ
（ホイールベース長），Ｉz （ヨー慣性モーメント），
Ｃf （前輪コーナリングパワ），Ｃr （後輪コーナリン
グパワ）を用いて、前記〔数５〕〔数６〕により規範ヨ
ーレートおよび規範横加速度の計算を行う。そして、計
算結果の規範ヨーレートと規範横加速度をスリップ検出
手段８へ出力する。In step 22, the calculating means 1 calculates the value of each signal obtained in step 21, and the constants M (vehicle weight) and a (a distance from the front axle to the center of gravity of the vehicle) stored in the storage section. , B (distance from the rear axle to the center of gravity of the vehicle), l
(Wheelbase length), I z (yaw moment of inertia),
Using C f (front wheel cornering power) and C r (rear wheel cornering power), the standard yaw rate and the standard lateral acceleration are calculated according to [Equation 5] and [Equation 6]. Then, the standard yaw rate and the standard lateral acceleration of the calculation result are output to the slip detecting means 8.
【００２４】ステップ２３において、ヨーレート検出手
段５からの信号および横加速度検出手段６からの信号を
スリップ検出手段８に読み込み、横加速度検出手段６か
らの信号と前後加速度検出手段７からの信号を路面摩擦
係数演算手段９に読み込む。ステップ２４において、ス
リップ検出手段８はヨーレート−規範ヨーレートと横加
速度−規範横加速度の計算を行う。ステップ２５におい
て、路面摩擦係数演算手段９は、前記〔数７〕の摩擦係
数μ（加速度）の計算を行う。In step 23, the signal from the yaw rate detecting means 5 and the signal from the lateral acceleration detecting means 6 are read into the slip detecting means 8, and the signal from the lateral acceleration detecting means 6 and the signal from the longitudinal acceleration detecting means 7 are read on the road surface. It is read into the friction coefficient calculation means 9. In step 24, the slip detecting means 8 calculates yaw rate-standard yaw rate and lateral acceleration-standard lateral acceleration. In step 25, the road surface friction coefficient calculating means 9 calculates the friction coefficient μ (acceleration) of the above [Formula 7].
【００２５】ステップ２６において、この計算結果か
ら、前記（１）〜（３）の３つのスリップ判定条件が成
立したか否かの判定を行う。成立しないときは、ステッ
プ２１へ戻り、成立した時にはステップ２７へ進む。ス
テップ２７において、１００ミリ秒が経過したか否かを
判定する。経過していなければ、ステップ２１へ戻り、
経過した時は、スリップが生じたと判定して、ステップ
２８へ進む。ステップ２８において、μの急変を防ぐた
め、次の〔数８〕のフィルタ処理を行う。In step 26, it is determined from the calculation result whether or not the three slip determination conditions (1) to (3) are satisfied. If not established, the process returns to step 21, and if established, the process proceeds to step 27. In step 27, it is determined whether 100 milliseconds have elapsed. If not, return to step 21,
When the time has elapsed, it is determined that slip has occurred, and the routine proceeds to step 28. In step 28, the following filter processing of [Equation 8] is performed in order to prevent a sudden change in μ.
【００２６】[0026]
【数８】 [Equation 8]
【００２７】ステップ２９では、スリップ判定直前のμ
値を静摩擦係数、スリップ判定中のμ値を動摩擦係数と
して検出する。At step 29, μ just before the slip judgment is made.
The value is detected as a static friction coefficient, and the μ value during slip determination is detected as a dynamic friction coefficient.
【００２８】[0028]
【発明の効果】本発明によれば、スリップ中すなわち車
両挙動が全て路面摩擦係数により左右される領域で本来
の定義により摩擦係数検出をしているので精度の良い摩
擦係数検出が行われる。そして、精度のよい摩擦係数が
得られることにより、路面摩擦係数情報に基づく各種足
廻り制御が正確に行われることとなる。According to the present invention, since the friction coefficient is detected according to the original definition in a region where the vehicle behavior is slipping, that is, the vehicle behavior is entirely influenced by the road surface friction coefficient, the friction coefficient can be detected with high accuracy. Then, by obtaining an accurate friction coefficient, various underbody control based on the road surface friction coefficient information can be accurately performed.
【図１】本発明の実施例のブロック図。FIG. 1 is a block diagram of an embodiment of the present invention.
【図２】図１のブロックの動作を説明するフローチャー
ト。FIG. 2 is a flowchart illustrating the operation of the blocks in FIG.
１…規範運動状態演算手段 ２…ハンドル角検出手段 ３…後輪舵角検出手段 ４…車速検出手段 ５…ヨーレート検出手段 ６…横加速度検出手段 ７…前後加速度検出手段 ８…スリップ検出手段 ９…路面摩擦係数演算手段 DESCRIPTION OF SYMBOLS 1 ... Normative motion state calculation means 2 ... Steering wheel angle detection means 3 ... Rear wheel steering angle detection means 4 ... Vehicle speed detection means 5 ... Yaw rate detection means 6 ... Lateral acceleration detection means 7 ... Longitudinal acceleration detection means 8 ... Slip detection means 9 ... Road friction coefficient calculation means
───────────────────────────────────────────────────── フロントページの続き (72)発明者 ▲高▼見 雅之 愛知県刈谷市昭和町１丁目１番地 日本電 装株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Taka ▼ Masayuki 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.
Claims (1)
ップが検知される直前に車両に発生している加速度と、
スリップ検知中の車両に発生している加速度を路面の摩
擦係数として検出することを特徴とする路面摩擦係数検
出方法。1. An acceleration occurring in the vehicle immediately before the slip is detected, the acceleration being detected immediately before the slip is detected,
A road surface friction coefficient detecting method, characterized in that an acceleration occurring in a vehicle during slip detection is detected as a road surface friction coefficient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28173292A JPH06127405A (en) | 1992-10-20 | 1992-10-20 | Detecting method for friction coefficient of road surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28173292A JPH06127405A (en) | 1992-10-20 | 1992-10-20 | Detecting method for friction coefficient of road surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06127405A true JPH06127405A (en) | 1994-05-10 |
Family
ID=17643216
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28173292A Pending JPH06127405A (en) | 1992-10-20 | 1992-10-20 | Detecting method for friction coefficient of road surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06127405A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11731638B2 (en) | 2020-07-15 | 2023-08-22 | Toyota Jidosha Kabushiki Kaisha | Driving assistance apparatus, driving assistance method, and non-transitory storage medium |
-
1992
- 1992-10-20 JP JP28173292A patent/JPH06127405A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11731638B2 (en) | 2020-07-15 | 2023-08-22 | Toyota Jidosha Kabushiki Kaisha | Driving assistance apparatus, driving assistance method, and non-transitory storage medium |
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