JP2004001624A - Travel speed control device and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly start vehicle speed control with preceding vehicle follow-up control even in the case of providing a function of performing throttle initial control of once increasing the throttle opening at the start of the preceding vehicle follow-up control. <P>SOLUTION: This travel speed control device has the throttle initial control function of once increasing the throttle opening at the start of vehicle speed control for controlling the travel speed of an own vehicle to allow the own vehicle to follow the preceding vehicle. The travel speed control device is provided with a correction part 47 obtaining an increase/decrease rate corresponding to vehicle-to-vehicle distance deviation ▵L and relative speed ▵V, from a map prepared beforehand at an increase/decrease rate map part 48 and multiplying the original throttle opening value implemented in throttle initial control, by the increase/decrease rate. <P>COPYRIGHT: (C)2004,JPO

Description

ここで、ａは係数であり、Ｌ_ｏｆはオフセット値である。なお、（２）式の関係からわかるように、車間距離指令値Ｌ^＊を自車速Ｖの関数として演算するようにしてもよい。この場合、（４）式により演算する。
【００３２】
Ｌ^＊＝ａ’・Ｖ＋Ｌ_ｏｆ　・・・（４）
ここで、ａ’は係数である。また、車間距離指令値Ｌ^＊は乗員が設定した設定値であってもよい。
車間距離指令値演算部２１は、算出した車間距離指令値Ｌ^＊を目標車間距離演算部２２に出力する。
【００３３】
一方、目標車間距離演算用定数決定部３０は、車間距離指令値演算部２１からの車間距離指令値Ｌ^＊を入力とし、車間距離センサ３により検出された車間距離Ｌを出力とする車間距離制御系において、車間距離Ｌが車間距離指令値Ｌ^＊に到達するまでの車間距離制御の応答特性を車間距離偏差△Ｌと相対速度△Ｖとに応じた最適な応答特性（以下、目標車間距離制御応答特性という。）とするために、車間距離制御系の減衰係数ζ_Ｔと固有振動数ω_Ｔとを車間距離偏差△Ｌと相対速度△Ｖとに応じて決定している。
【００３４】
ここで、車間距離偏差△Ｌは下記（５）式となる。
△Ｌ＝Ｌ−Ｌ^＊　・・・（５）
具体的には、種々の追従場面において最適な車間距離制御の応答特性が得られるように、車間距離偏差△Ｌと相対速度△Ｖとに応じた車間距離制御系の減衰係数ζ_Ｔと固有振動数ω_Ｔとを予めマップとして設定し、追従制御時の車間距離偏差△Ｌと相対速度△Ｖとに対応する減衰係数ζ_Ｔと固有振動数ω_Ｔとを目標車間距離演算用定数として決定する。
【００３５】
図４は、そのような処理を実現する目標車間距離演算用定数決定部３０の構成例を示す。この目標車間距離演算用定数決定部３０は、車間距離Ｌ、車間距離指令値Ｌ^＊に基づいて車間距離偏差ΔＬを算出する車間距離偏差演算部３１と、減衰係数ζ_Ｔ及び固有振動数ω_Ｔの算出用のマップが格納されているマップ部３２と、相対速度ΔＶと車間距離偏差ΔＬとをもとにマップ部３２のマップに基づいて固有振動数ω_Ｔを算出する固有振動数算出部３３と、相対速度ΔＶと車間距離偏差ΔＬとをもとにマップ部３２のマップ部に基づいて減衰係数ζ_Ｔを算出する車間距離指令値演算部３４とを備えている。
【００３６】
このように構成されている目標車間距離演算用定数決定部３０は、決定した減衰係数ζ_Ｔと固有振動数ω_Ｔとを目標車間距離演算部２２に出力する。
目標車間距離演算部２２は、車間距離指令値演算部３４からの減衰係数ζ_Ｔ及び固有振動数ω_Ｔを用いて、車間距離指令値Ｌ^＊を下記（６）式に示す二次形式のフィルターを通して目標車間距離Ｌ_Ｔと目標相対速度△Ｖ_Ｔとを演算する。なお、先行車を認識した直後の車間距離Ｌ_０と相対速度△Ｖ_０とを初期値にする。
【００３７】
【数１】

【００３８】
この（６）式により演算される目標車間距離Ｌ_Ｔと目標相対速度△Ｖ_Ｔとは、実車間距離Ｌが目標車間距離制御応答特性を経て車間距離指令値Ｌ^＊に収束するように、車間距離偏差ΔＬと相対速度ΔＶとの時間的推移を規定した最終車間距離指令値を示す。
この（６）式を展開してラプラス変換すると下記（７）式のように表すことができる。
【００３９】
Ｌ_Ｔ（ｓ）／Ｌ^＊（ｓ）＝ω_Ｔ ^２／（ｓ^２＋２ζ_Ｔω_Ｔｓ＋ω_Ｔ ^２）　・・・（７）
この（７）式は車間距離指令値Ｌ^＊に対する目標車間距離Ｌ_Ｔの伝達関数であり二次式で表される。この実施の形態では、車間距離制御系において、実車間距離Ｌが前記（７）式で表される目標車間距離Ｌ_Ｔ（最終車間距離指令値）となるようにフィードバック制御を行う。前述したように、車間距離制御系の減衰係数ζ_Ｔ及び固有振動数ω_Ｔに、車間距離偏差△Ｌと相対速度△Ｖとに応じた目標車間距離制御応答が得られる値を設定したので、種々の追従場面において望ましい車間距離制御応答を実現できる。
【００４０】
なお、目標車間距離制御応答特性としては、割り込み場面や追い抜き場面等において、先行車両との車間距離が車間距離指令値を下回っているときでも、先行車両との相対速度が小さい場合は急な減速を行わず、実車間距離が車間距離指令値にゆっくりと収束するような応答が望ましい。また、接近場面等において相対速度が大きいときでも車間距離が長い場合は急な減速を行わず、車間距離が指令値にゆっくりと収束するような応答が望ましい。このような追従場面では、実車間距離が指令値をオーバーシュート又はアンダーシュートしてから収束するような二次の応答特性となり、そのような応答を前記（６）式及び（７）式で表す二次のフィルターにより実現することかできる。
【００４１】
目標車間距離演算部２２は、このようにして得た車間距離偏差△Ｌと相対速度△Ｖとを車速指令値演算部２３に出力する。
車速指令値演算部２３は、所定の定数ｆ_Ｖ，ｆ_Ｌを用いて下記（８）式により車速指令値Ｖ^＊を演算し、求めた車速指令値Ｖ^＊を車速制御部４０に出力する。
Ｖ^＊＝Ｖ（ｔ）＋△Ｖ（ｔ）−｛ｆ_Ｖ（△Ｖ_Ｔ（ｔ）−△Ｖ（ｔ））＋ｆ_Ｌ（Ｌ_Ｔ（ｔ）−Ｌ（ｔ））｝　　・・・（８）
ここで、ｆ_Ｖは目標相対速度偏差（目標相対速度△Ｖ_Ｔ（ｔ）と相対速度検出値△Ｖ（ｔ）との差、（△Ｖ_Ｔ（ｔ）−△Ｖ（ｔ）））　に乗ずる定数であり、ｆ　_Ｌは目標車間距離偏差（目標車間距離Ｌ_Ｔ（ｔ）と車間距離検出値Ｌ（ｔ）との差、（Ｌ_Ｔ（ｔ）−Ｌ（ｔ）））に乗ずる定数である。
【００４２】
以上が先行車追従制御部２０の構成の詳細である。なお、先行車追従制御部２０は、車間距離センサ３により先行車両を検出できない場合は、乗員が目標車速として設定した車速を車速指令値Ｖ^＊として車速制御部４０へ出力する。
次に、車速制御部４０の詳細を説明する。
車速制御部４０は、車速指令値Ｖ_ＣＯＭ（ｔ）と自車速Ｖ_Ａ（ｔ）を入力し駆動トルク指令値ｄ_ＦＣ（ｔ）を演算する。ここで、車速指令値Ｖ_ＣＯＭ（ｔ）は、前記車速指令値Ｖ^＊の各時刻ｔにおける値に対応し、自車速Ｖ_Ａ（ｔ）は、前記自車速Ｖの各時刻ｔにおける値に対応している。
【００４３】
図５は、車速制御部４０の構成例を示す。この車速制御部４０は、モデルマッチング補償器部４１、外乱推定器部４２、ブレーキ圧指令値算出部４３、エンジントルク指令値算出部４４、スロットル開度指令値算出部４５、変速比指令値算出部４６、補正部４７及び増減率マップ部４８を備えている。
この車速制御部４０では、車速指令値Ｖ_ＣＯＭ（ｔ）を入力とし、自車速Ｖ_Ａ（ｔ）を出力としており、この場合、その伝達特性Ｇ_Ｖ（ｓ）を下記（９）式で表すことができる。
【００４４】
Ｇ_Ｖ（ｓ）＝１／（Ｔ_Ｖ・ｓ　＋１）・ｅ^{−Ｌｖ・ｓ}　・・・（９）
ここで、Ｔ_Ｖは１次遅れ時定数であり、Ｌ_Ｖはパワートレイン系の遅れによる無駄時間である。
また、制御対象の車両モデルを駆動トルク指令値ｄ_ＦＣ（ｔ）を操作量とし、自車速Ｖ_Ａ（ｔ）を制御量としてモデル化することによって、車両のパワートレインの挙動を下記（１０）式に示す簡易線形モデルとして表すことができる。
【００４５】
Ｖ_Ａ（ｔ）＝１／（ｍ_Ｖ・Ｒｔ　・ｓ）・ｅ^{−Ｌｖ・ｓ}・ｄ_ＦＣ（ｔ）　・・・（１０）
ここで、Ｒｔはタイヤの有効回転半径であり、ｍ_Ｖは車両質量である。
この（１０）式に示すような駆動トルク指令値ｄ_ＦＣ（ｔ）を入力とし、自車速Ｖ_Ａ（ｔ）を出力とする車両モデルは、１／ｓの形となるので積分特性を有することになる。
【００４６】
なお、制御対象の特性にはパワートレイン系の遅れにより無駄時間Ｌ_Ｖも含まれ、かつ、使用するアクチュエータやエンジンによって無駄時間Ｌ_Ｖの値が変化する非線形特性に、後述するように、近似ゼロイングモデルによる外乱推定器を用いることで、駆動トルク指令値ｄ_ＦＣ（ｔ）を入力とし、自車速Ｖ_Ａ（ｔ）を出力とする車両モデルを上記と同じ式で表すことができる。
【００４７】
ここで、車速指令値Ｖ_ＣＯＭ（ｔ）を入力とし、自車速Ｖ_Ａ（ｔ）を出力とした場合の制御対象の応答特性を、予め定めた一次遅れＴ_Ｈと無駄時間Ｌ_Ｖという要素をもつ伝達特化Ｇ_Ｖ（ｓ　）の特定に一致させると、前記図５に示すモデルマッチング補償器部４１を構成する補償器Ｃ_３（ｓ）、外乱推定器部４２を構成する補償器Ｃ_１（ｓ），Ｃ_２（ｓ）を用いて次のように定めることができる。なお、補償器Ｃ_１（ｓ），Ｃ_２（ｓ）は近似ゼロイング手法を採用して外乱推定器部４２を構成し、これら補償器Ｃ_１（ｓ），Ｃ_２（ｓ）は外乱やモデル変化誤差による影響を抑制するように機能し、また、補償器Ｃ_３（ｓ）は、モデルマッチング手法を採用してモデルマッチング補償器部４１を構成している。
【００４８】
外乱推定器部４２を構成する補償器Ｃ_１（ｓ），Ｃ_２（ｓ）をそれぞれ下記（１１）式及び（１２）式として表すことができる。
Ｃ_１（ｓ）＝ｅ^{−Ｌｖ・ｓ}／（Ｔ_Ｖ・ｓ＋１）　・・・（１１）
Ｃ_２（ｓ）＝（ｍ_ｖ・Ｒｔ・ｓ）／（Ｔ_Ｖ・ｓ＋１）　・・・（１２）
このような補償器Ｃ_１（ｓ），Ｃ_２（ｓ）である場合、外乱推定値ｄ_Ｖ（ｔ）は、下記（１３）式となる。
【００４９】
ｄ_Ｖ（ｔ）＝Ｃ_２（ｓ）・Ｖ_Ａ（ｔ）−Ｃ_１（ｓ）・ｄ_ＦＣ（ｔ）・・・（１３）
また、制御対象の無駄時間を無視して、規範モデルＧ_Ｖ（ｓ）を時定数Ｔ_Ｖの１次ローパスフィルタとすると、モデルマッチング補償器部４１を構成する補償器Ｃ_３（ｓ）を下記（１４）式として表すことができる。
【００５０】
Ｃ_３（ｓ）＝ｍ_Ｖ・Ｒｔ／Ｔ_Ｖ　・・・（１４）
以上のような補償器Ｃ_１（ｓ）、Ｃ_２（ｓ）、Ｃ_３（ｓ）により、駆動トルク指令値ｄ_ＦＣ（ｔ）が下記（１５）式として算出される。
ｄ_ＦＣ（ｔ）＝Ｃ_３（ｓ）・｛ＶＣ_ＣＯＭ（ｔ）−Ｖ_Ａ（ｔ）｝−｛Ｃ_２（ｓ）・Ｖ_Ａ（ｔ）−Ｃ_１（ｓ）・ｄ_ＦＣ（ｔ）｝　・・・（１５）
エンジントルク指令値算出部４４では、この駆動トルク指令値ｄ_ＦＣ（ｔ）と実変速比ＲＡＴＩＯ（ｔ）とに基づいてエンジントルク指令値ＴＥ_ＣＯＭ（ｔ）を下記（１６）により算出する。
【００５１】
ＴＥ_ＣＯＭ（ｔ）＝ｄ_ＦＣ（ｔ）／｛Ｇｆ・ＲＡＴＩＯ（ｔ）｝・・・（１６）
ここで、Ｇｆはファイナルギヤ比である。
そして、スロットル開度指令値算出部４５は、このエンジントルク指令値ＴＥ_ＣＯＭ（ｔ）とエンジン回転速度Ｎｅ（ｔ）とに基づいてエンジン全性能マップより目標スロットル開度ＴＶＯ_ＣＯＭ（ｔ）を算出する。図６は、エンジン全性能マップの一例であるエンジン非線形定常特性マップであり、エンジントルクとスロットル開度との関係をエンジン回転速度をパラメータとして示しており、このようなエンジン全性能マップよりエンジントルク指令値ＴＥ_ＣＯＭ（ｔ）とエンジン回転速度Ｎｅ（ｔ）とに基づいて目標スロットル開度ＴＶＯ_ＣＯＭ（ｔ）を得る。そして、スロットル開度指令値算出部４５は、目標スロットル開度ＴＶＯ_ＣＯＭ（ｔ）をスロットル制御部６０に出力する。
【００５２】
なお、補正部４７及び増減率マップ部４８は、先行車追従制御の開始時において、その開始時に実施するスロットルイニシャル制御を補正するための構成であり、後で詳述する。
以上が車速制御部４０の構成の詳細である。
次に、スロットル制御部６０の詳細を説明する。スロットル制御部６０は、目標スロットル開度ＴＶＯ_ＣＯＭ（ｔ）が入力され、その入力に応じた駆動信号指令値Ｄｕｔｙ（ｔ）をスロットルアクチュエータ７０へ出力する。図７は、そのような処理を実現するスロットル制御部６０の構成例を示す。このスロットル制御部６０は、モデルマッチング補償器部６１、外乱推定器部６２及び非線形補償器６３を備えている。
【００５３】
ここで、制御対象であるスロットルアクチュエータ７０の制御モデルは、補償前駆動信号（Ｄｕｔｙ比）指令値Ｄｕｔｙ＿Ｒ（ｔ）を操作量とし、スロットル開度相当量ＴＶＯ（ｔ）を制御量としてモデル化することによって、下記（１７）式に示す簡易線形モデルとして表される。
ＴＶＯ（ｔ）＝（ｋａ／ｓ）．ｅ^{−Ｌａ・ｓ}・Ｄｕｔｙ＿Ｒ（ｔ）・・・（１７）
ここで、ｋａは積分ゲイン（Ｄｕｔｙ１００％時の開閉速度）であり、Ｌａは無駄時間である。
【００５４】
このように補償前駆勤信号（Ｄｕｔｙ比）指令値Ｄｕｔｙ＿Ｒ（ｔ）を入力とし、スロットル開度相当量ＴＶＯ（ｔ）を出力とする制御モデルは、１／ｓの形となるので積分特性を有することがわかる。
なお、制御対象の特性には、使用するスロットルアクチュエータ７０により無駄時間Ｌａが変わる非線形特性を有するが、後述するように、近似ゼロイング手法による外乱推定器を用いることにより、補償前駆動信号（Ｄｕｔｙ比）指令値Ｄｕｔｙ＿Ｒ（ｔ）を入力とし、スロットル開度相当量ＴＶＯ（ｔ）を出力とする制御モデルを上式と同じ式で表すことができる。
【００５５】
ここで、補償前駆動信号（Ｄｕｔｙ比）指令値Ｄｕｔｙ＿Ｒ（ｔ）を入力とし、スロットル開度相当量ＴＶＯ（ｔ）を出力とした場合の制御対象の応答特性を、予め定めた一次遅れＴａや無駄時間Ｌａといった要素をもつ伝達特性Ｇａ（ｓ）の特性に一致させると、前記図７に示すモデルマッチング補償器部６１を構成する補償器Ｃ_６（ｓ）、外乱推定器部６２を構成する補償器Ｃ_４（ｓ），Ｃ_５（ｓ）を用いて次のように定めることができる。なお、補償器Ｃ_４（ｓ），Ｃ_５（ｓ）は近似ゼロイング手法を採用して外乱推定器部６２を構成し、これら補償器Ｃ_４（ｓ），Ｃ_５（ｓ）は外乱やモデル変化誤差による影響を抑制するように機能し、また、補償器Ｃ_６（ｓ）は、モデルマッチング手法を採用してモデルマッチング補償器部６１を構成している。
【００５６】
外乱推定器部６２を構成する補償器Ｃ_４（ｓ），Ｃ_５（ｓ）をそれぞれ下記（１１）式及び（１２）式として表すことができる。
Ｃ_４（ｓ）＝ｅ^{−Ｌａ・ｓ}／（Ｔ_ａ・ｓ＋１）　　・・・（１８）
Ｃ_５（ｓ）＝ｓ／｛（ｋａ・（Ｔ_ａ・ｓ＋１）｝　・・・（１９）
このような補償器Ｃ_４（ｓ），Ｃ_５（ｓ）である場合、外乱推定値ｄ_Ｖａ（ｔ）は、下記（２０）式となる。
【００５７】

また、制御対象の無駄時間を無視して、規範モデルを時定数Ｔ_ｂの１次ローパスフィルタとすると、モデルマッチング補償器部６１を構成する補償器Ｃ_６（ｓ）を下記（２１）式として表される。
【００５８】
Ｃ_６（ｓ）＝１／（ｋａ・Ｔ_ｂ）　・・・（２１）
以上のような補償器Ｃ_４（ｓ），Ｃ５（ｓ），Ｃ６（ｓ）により、補償前駆動信号（Ｄｕｔｙ比）指令値Ｄｕｔｙ＿Ｒ（ｔ）が下記（２２）式として算出される。

さらに、スロットルアクチュエータ７０に負圧式アクチュエータを用いた場合、負圧を作るバキュームモータのＯＮ／ＯＦＦ時やベントバルブ開閉時の摩擦など非線形要素の影響を受け易い。そのため、非線形補償部６３で、そのようにようにして算出した補償前駆動信号（Ｄｕｔｙ比）指令値Ｄｕｔｙ＿Ｒ（ｔ）に対して図８に示すようなマップを用いて非線形補償を施したバキューム（ＶＡＣ）／ベント（ＶＥＮＴ）駆動信号Ｄｕｔｙ（ｔ）を得て、この値をスロットルアクチュエータ７０に出力する。
【００５９】
ここで、非線形補償マップは、図８に示すように、補償前駆動信号（Ｄｕｔｙ比）指令値Ｄｕｔｙ＿Ｒ（ｔ）からＶＡＣ／ＶＥＮＴ駆動信号Ｄｕｔｙ（ｔ）を算出するためのマップである。例えば、Ｄｕｔｙ＿Ｒ（ｔ）≧０の場合はバキュームモータ駆動信号を出力し、Ｄｕｔｙ＿Ｒ（ｔ）＜０の場合はベントバルブ駆動信号を出力するようなマップになっている。
【００６０】
なお、負圧式アクチュエータは、負圧を動力源として動作するものであるが、そのための負圧をバキュームモータを駆動して作ってもよいし、吸気管負圧を利用して発生させてもよい。また、負圧式アクチュエータにおいては、バキューム（ＶＡＣ）のときはスロットルを開き、ベント（ＶＥＮＴ）のときはスロットルを閉じるように駆動する。
【００６１】
ここで、負圧式アクチュエータとしてのスロットルアクチュエータ７０の構成を説明する。図９は、そのスロットルアクチュエータ７０の構成例を示す。
スロットルアクチュエータ７０は、大別して、アクチュエータ７１、バキュームポンプ７２、ベントバルブ７３及びセーフティバルブ７４から構成されており、アクチュエータ７１とバキュームポンプ７２とが接続されている管路途中にベントバルブ７３及びセーフティバルブ７４が配置されている。
【００６２】
アクチュエータ７１は、負圧室７１ａをダイヤフラム７１ｂにより区画して形成しており、ダイヤフラム７１ｂにスロットルバルブに接続されているアクセルワイヤ７１ｃが取り付けられている。また、バキュームポンプ７２は、モータ７２ａによりダイヤフラム７２ｂを駆動して、前記アクチュエータ７１の負圧室７１ａを負圧にするように構成されている。そして、ベンドバルブ７３及びセーフティバルブ７４はアクチュエータ７１の負圧室７１ａの負圧を抜いて大気圧にするためのものであり、ベントバルブ７３はベントバルブソレノイド７３ａが制御されることで駆動し、また、セーフティバルブ７４はバキュームポンプモータ７４ａが制御されることで駆動するようになっている。なお、セーフティバルブ７４は大気に連通しており、車速制御を解除したり、何らかの異常を検出した場合に車速制御を停止させるものとして機能している。
【００６３】
このようなスロットルアクチュエータ７０では、バキュームポンプ７２、ベントバルブ７３を適宜駆動することにより、負圧に応じてアクチュエータ７１のダイヤフラム７１ｂを移動（図９において左右方向に移動）させ、ダイヤフラム７１ｂに接続されているアクセルワイヤ７１ｃを介してスロットルバルブの開閉を行っている。
【００６４】
これにより、コントロールユニット１００を構成している車速制御部４０は、スロットル開度指令値をスロットル制御部６０に出力して、スロットル制御部６０及び信号線１０１を介して、このように構成されているスロットルアクチュエータ７０のバキュームポンプ７２、ベントバルブ７３及びセーフティバルブ７４を適宜制御し、エンジンのスロットルバルブを調節している。スロットル制御部６０が信号線１０１を介して出力するスロットル開度指令値は、前記バキューム（ＶＡＣ）駆動信号Ｄｕｔｙ（ｔ）或いはベント（ＶＥＮＴ）駆動信号Ｄｕｔｙ（ｔ）に対応する。
【００６５】
以上が走行速度制御装置の全体構成、及び走行速度制御装置を構成する先行車追従制御部２０、車速制御部４０及びスロットル制御部６０、及びスロットルアクチュエータ７０の説明である。
そして、この走行速度制御装置は、本発明を適用することによるスロットルイニシャル制御を補正することが可能になっており、次にこれについて説明する。
【００６６】
スロットルイニシャル制御とは、前述したように、例えば特開平９−２０７６１６号公報に開示されているように、スロットル全閉状態から設定車速に対応するスロットル開度に円滑に繋がるようにするための車速制御の初期制御である。本発明の適用により、走行速度制御装置は、このようなスロットルイニシャル制御を先行車追従制御の開始時に実行するようにし、自車両が先行車両に近づいている状態（車間距離が比較的短い）或いは車間距離はあるが相対速度がマイナス側に非常に大きい状態（自車両が先行車両に接近していく状態）である場合、またその逆に、自車両が先行車両からかなり離れている状態或いは相対速度がプラス側に非常に大きい状態（自車両が先行車両から離れていく状態）である場合、実施するスロットルイニシャル制御を適宜補正している。具体的には、次のように補正している。
【００６７】
前述したように、先行車追従制御部２０により車間距離Ｌや相対速度ΔＶを計測しているが、スロットルイニシャル制御の補正として、この車間距離Ｌ及び相対速度ΔＶに応じてスロットルイニシャル制御のための制御信号を補正している。ここでは、前記車速制御部４０のスロットル開度指令値算出部４５が算出したスロットルイニシャル制御時の制御信号である目標スロットル開度（以下、目標スロットル開度初期値Ｔ_ｖｏｒｉという。）を補正する場合について複数の例を挙げて説明する。
【００６８】
先ず、第１の補正方法では、車間距離Ｌや相対速度ΔＶから自車両が先行車両に近づいている状態或いは車間距離はあるが相対速度がマイナス側に非常に大きい状態である場合に、前記目標スロットル開度初期値Ｔ_ｖｏｒｉを０にしている。すなわち、スロットルイニシャル制御を行わずに、通常の車速制御を開始させるようにする。
【００６９】
具体的な構成として説明すると、図５に示す車速制御部４０の補正部４７が、スロットル開度指令値算出部４５が通常のスロットルイニシャル制御を行うために算出した目標スロットル開度ＴＶＯ_ＣＯＭ（ｔ）である目標スロットル開度初期値Ｔ_ｖｏｒｉを０することになる。
或いは、第２の補正方法として、車間距離Ｌ及び相対速度ΔＶに基づいて所定のマップを用いて増減率（Ｔ_{ｖｏｒｉａｄｊ}）を求め、下記（２３）式に示すように、それを目標スロットル開度初期値Ｔ_ｖｏｒｉに乗じて、新たな目標スロットル開度初期値する方法が挙げられる。
【００７０】
Ｔ_ｖｏｒｉ＝Ｔ_ｖｏｒｉ×Ｔ_{ｖｏｒｉａｄｊ}　・・・（２３）
例えば、前記所定のマップとしては、図１０に示すように、車間距離偏差ΔＬ（＝Ｌ−Ｌ^＊）と相対速度ΔＶとから増減率Ｔ_{ｖｏｒｉａｄｊ}を決定することができるマップが挙げられる。このマップでは、相対速度ΔＶが大きい程、又は車間距離偏差ΔＬが大きい程、高い増減率Ｔ_{ｖｏｒｉａｄｊ}になるようになっており、また、相対速度ΔＶが小さい程（マイナス側に大きい程）、又は車間距離偏差ΔＬが小さい程（マイナス側に大きい程）、低い増減率Ｔ_{ｖｏｒｉａｄｊ}になる。
【００７１】
このようなマップを利用すれば、自車両が先行車両に近づいている状態或いは車間距離はあるが相対速度がマイナス側に非常に大きい状態である場合には、増減率Ｔ_{ｖｏｒｉａｄｊ}が低くなる或いは０になるので、元の目標スロットル開度初期値Ｔ_ｖｏｒｉに比べて新たな目標スロットル開度初期値Ｔ_ｖｏｒｉが小さい値或いは０に決定される。その逆に、自車両が先行車両からかなり離れている状態或いは相対速度がプラス側に非常に大きい状態である場合には、増減率Ｔ_{ｖｏｒｉａｄｊ}が高くなるので、元の目標スロットル開度初期値Ｔ_ｖｏｒｉに比べて新たな目標スロットル開度初期値Ｔ_ｖｏｒｉが大きな値に決定される。
【００７２】
この第２の補正方法を具体的な構成として説明すると、図５に示す車速制御部４０の補正部４７が、増減率マップ部４８に保持されている前記マップに基づいて、スロットル開度指令値算出部４５が算出した目標スロットル開度初期値Ｔ_ｖｏｒｉを増減率Ｔ_{ｖｏｒｉａｄｊ}で補正することになる。
以上のような第１及び第２の補正方法により、車間距離が基準距離よりも小さいとき又は相対速度に基づいて自車両が先行車両に近づいていると検出したときには、スロットルイニシャル制御で実施するスロットル開度の増加量を抑える補正をし、その逆に、車間距離が基準距離よりも大きいとき又は相対速度に基づいて自車両が先行車両から遠ざかっていると検出したときには、スロットルイニシャル制御で実施するスロットル開度の増加量を増やす補正をしている。ここで、基準距離は車間距離指令値Ｌ^＊である。
【００７３】
以上のように、走行速度制御装置では、スロットルイニシャル制御を適宜補正している。
次に、走行速度制御装置の車速制御の際の処理手順を説明する。図１１は、その車速制御のメインルーチンのフローチャートを示す。この実施の形態では、走行速度制御装置の制御をコントロールユニットのマイクロコンピュータにより実現しており、コントロールユニットのマイクロコンピュータが所定時間（例えば、１００ｍｓｅｃ）で図１１に示す処理手順をメインルーチンとして実行している。
【００７４】
先ず、ステップＳ１において、走行速度センサ４と図示しないエンジン回転数センサの計測値に基づいて実車速Ｖｓｐとエンジン回転速度Ｎｅを演算するとともに、図示しないスロットルセンサによりスロットル実開度を計測する。
続いてステップＳ２において、ステアリングホイール等に設けられているＡＳＣＤ制御（オートスピードコントロール）のキャンセルスイッチが操作されたか否かを判定する。ここで、キャンセルスイッチが操作されている場合、ステップＳ１９に進み、セーフティバルブ７４を閉にして当該処理をリターンし、キャンセルスイッチが操作されていない場合、ステップＳ３に進む。
【００７５】
なお、キャンセルスイッチの操作状態を判定をするとともに、フットブレーキが操作されたか否かをブレーキスイッチにより判定してもよい。すなわち、ブレーキスイッチによりフットブレーキが操作されたか否かを判定し、フットブレーキが操作されている場合、ステップＳ１９に進み、セーフティバルブ７４を閉にして当該処理をリターンする。
【００７６】
ここで、キャンセルスイッチが操作されている場合、或いはフットブレーキが操作されている場合にする処理は、具体的には、定速走行制御の解除を決定し、定速走行制御中を示すＡＳＣＤ制御中フラグと各種変数とを初期化する処理である。
一方、ステップＳ３では、ステアリングホイール等に設けられているＡＳＣＤ制御のセットスイッチが操作されたか否かを判定する。ここで、セットスイッチが操作されている場合、すなわち先行車追従制御の実行開始命令がなされた場合、ステップＳ４に進み、セットスイッチが操作されていない場合、ステップＳ９に進む。
【００７７】
ステップＳ４〜ステップＳ８に示す処理は、スロットルイニシャル制御のための処理であり、すなわちここでは、前述したようなスロットルイニシャル制御の補正処理も行う。
先ず、ステップＳ４では、設定車速を目標車速Ｖｓｐｒに設定して記憶し、続くステップＳ５において、予めメモリに記憶したマップから前記目標車速Ｖｓｐｒで平坦路を走行した場合の走行抵抗Ｒを求め、これを目標駆動力初期値Ｆ_ｏｒｉとして記憶する。
【００７８】
そして、目標駆動力初期値（或いは目標駆動トルク初期値）Ｆ_ｏｒｉを得るのに必要なバキュームポンプ７２への出力パルス幅初期値であるアクチュエータ出力幅初期値Ｔ_ｖａｃｉを次のように求める。
先ず、ステップＳ６において、目標駆動力初期値Ｆ_ｏｒｉを用いて目標エンジントルク初期値Ｔ_ｅｒｉを下記（２４）式により演算する。ここでの演算は、前記車速制御部４０のエンジントルク指令値算出部４４におけるエンジントルク指令値ＴＥ_ＣＯＭ（ｔ）の演算に対応する。
【００７９】
Ｔ_ｅｒｉ＝（Ｆ_ｏｒｉ・Ｒｔ）／Ｇｍ・Ｇｆ　・・・（２４）
ここで、Ｇｍはトランスミッションのギヤ比であり、Ｒｔはタイヤの回転有効半径である。
さらに、このようにして算出した目標エンジントルク初期値Ｔ_ｅｒｉとエンジン回転速度Ｎｅから前記図６に示したエンジン非線形定常特性マップを用いて、目標スロットル開度初期値Ｔ_ｖｏｒｉを演算する。ここでの演算は、前記車速制御部４０のスロットル開度指令値算出部４５における目標スロットル開度ＴＶＯ_ＣＯＭ（ｔ）の演算に対応する。
【００８０】
そして、前述したような、第１の補正方法或いは第２の補正方法により、車間距離Ｌや相対速度ΔＶに基づいて、目標スロットル開度初期値Ｔ_ｖｏｒｉを補正することによるスロットルイニシャル制御の補正処理を行う。
すなわち、車間距離Ｌや相対速度ΔＶの検出結果が、自車両が先行車両に近づいている状態或いは車間距離はあるが相対速度がマイナス側に非常に大きい状態であることを示す場合、目標スロットル開度初期値Ｔ_ｖｏｒｉをゼロにする。或いは、マップを利用して、元の目標スロットル開度初期値Ｔ_ｖｏｒｉに比べて新たな目標スロットル開度初期値Ｔ_ｖｏｒｉを小さな値にする。これにより、スロットルイニシャル制御が実施されず、通常の車速制御が開始される。
【００８１】
その逆に、車間距離Ｌや相対速度ΔＶの検出結果が、自車両が先行車両からかなり離れている状態或いは相対速度がプラス側に非常に大きい状態であることを示す場合、マップを利用して、元の目標スロットル開度初期値Ｔ_ｖｏｒｉに比べて新たな目標スロットル開度初期値Ｔ_ｖｏｒｉを大きな値にする。
そして、ステップＳ７において、下記（２５）式により目標スロットル開度初期値Ｔ_ｖｏｒｉからアクチュエータ出力パルス幅初期値Ｔ_ｖａｃｉを演算する。
【００８２】
Ｔ_ｖａｃｉ　＝　Ｔ_ｖｏｒｉ　／　Ｋａ　＋　Ｌａ　・・・（２５）
ここで、ｋａは積分ゲイン（Ｄｕｔｙ１００％時の開閉速度）であり、Ｌａは無駄時間である。
このように、ステップＳ６及びステップＳ７において、目標駆動力初期値Ｆ_ｏｒｉを得るのに必要なバキュームポンプ７２への出力パルス幅初期値であるアクチュエータ出力幅初期値Ｔ_ｖａｃｉを求め、その後、ステップ８において、定速走行制御中を示すＡＳＣＤ制御中フラグ及びスロットルイニシャル制御の実行を示すイニシャルフラグをセットし、当該処理をリターンする。
【００８３】
一方、ステップ３でセットスイッチが操作されていない場合に進むステップ９では、ＡＳＣＤ制御中フラグがセットされているか否かを判定する。ここで、ＡＳＣＤ制御中フラグがセットされていない場合、前記ステップＳ１９に進み、セーフティバルブ７４を閉にして当該処理をリターンし、前記ＡＳＣＤ制御中フラグがセットされている場合、ステップＳ１０に進む。
【００８４】
ステップＳ１０では、前記イニシャルフラグがセットされているか否かを判定する。ここで、イニシャルフラグがセットされている場合、ステップＳ１５に進み、イニシャルフラグがセットされていない場合、ステップＳ１１に進む。
ステップＳ１１では、車速フィードバック制御を行い、車速制御演算としての目標駆動力を演算し、続くステップＳ１２において、その目標駆動力から目標スロットル開度を演算し、さらに続くステップＳ１３において、そのスロットル開度を目標値とするアクチュエータ出力パルス幅を演算する。そして、続くステップＳ１４において、このアクチュエータ出力パルス幅に基づいて前記バキューム（ＶＡＣ）バルブ駆動信号Ｔ_ｖａｃやベント（ＶＥＮＴ）バルブ駆動信号Ｔ_ｖｅｎｔをスロットルアクチュエータ７０のバキュームポンプ７２やベントバルブ７３に出力する。
【００８５】
ここで、このステップＳ１１〜ステップＳ１４の処理は、前記図３〜図９を用いて具体的に説明した演算式により実現している。また、このステップＳ１１〜ステップＳ１４の処理は、イニシャルフラグがセットされていない場合の処理であり、すなわち、スロットルイニシャル制御の実施後の先行車追従制御における処理になる。
【００８６】
一方、ステップＳ１０でイニシャルフラグがセットされている場合に進むステップＳ１５ではセーフティバルブ７４を閉じ、ステップＳ１６に進む。
ステップＳ１６では、前記アクチュエータ出力パルス幅Ｔ_ｖａｃｉが１００ｍｓ以下か否かを判定する。ここで、アクチュエータ出力パルス幅Ｔ_ｖａｃｉが１００ｍｓ以下の場合、ステップ１６に進み、スロットルイニシャル制御であるスロットル開度の初期設定が完了したと判断してイニシャルフラグをクリアし、前記ステップＳ１４に進む。一方、アクチュエータ出力パルス幅Ｔ_ｖａｃｉが１００ｍｓより大きい場合、ステップ１８に進み、アクチュエータ出力パルス幅Ｔ_ｖａｃｉから１００ｍｓを引いて、この値をアクチュエータ出力パルス幅Ｔ_ｖａｃｉとして新たに設定し、前記ステップＳ１４に進む。そして、アクチュエータ出力パルス幅Ｔ_ｖａｃｉに基づいてバキューム（ＶＡＣ）バルブ駆動信号Ｔ_ｖａｃやベント（ＶＥＮＴ）バルブ駆動信号Ｔ_ｖｅｎｔを得て、この信号をスロットルアクチュエータ７０のバキュームポンプ７２やベントバルブ７３に出力する。
【００８７】
以上が、走行速度制御装置の構成及びその処理内容（動作内容）である。
本発明を適用した走行速度制御装置は、前述したように、先行車追従制御の開始時に、車間距離Ｌや相対速度ΔＶに基づいて自車両が先行車両に近づいている状態或いは車間距離はあるが相対速度がマイナス側に非常に大きい状態を検出したとき、目標スロットル開度初期値を小さくし或いは０にして、またその逆に、車間距離Ｌや相対速度ΔＶに基づいて自車両が先行車両からかなり離れている状態或いは相対速度がプラス側に非常に大きい状態を検出したとき、目標スロットル開度初期値を大きくしている。
【００８８】
このように、スロットルイニシャル制御のパラメータである目標スロットル開度初期値を、車間距離Ｌや相対速度ΔＶに応じて適宜補正することで、先行車追従制御の開始時の不必要な加速又は二段階の加速をなくすことができるので、先行車追従制御を円滑に開始することができ、ドライバーの違和感をなくすことができる。
【００８９】
その効果について、図１２乃至図１４を用いて具体的に説明する。
図１２は、スロットルイニシャル制御を説明するための図である。また、図１３は、自車両が先行車両に近づいている場合或いは車間距離はあるが相対速度がマイナス側に非常に大きい場合における、本発明と従来例との効果の比較を示す図であり、さらに、図１４は、自車両が先行車両からかなり離れている場合或いは相対速度がプラス側に非常に大きい場合における、本発明と従来例との効果の比較を示す図である。
【００９０】
図１２に示すように、スロットルイニシャル制御では、車速制御の開始時に、設定速度を維持するために必要なスロットル開度までアクチュエータの最大開速度でスロットルバルブを開くことで（図１２中（Ａ−１）に示すスロットル開度のＡ点）、その操作以降の制御が円滑に開始されるようになる（図１２中（Ａ−２））。
【００９１】
しかし、自車両が先行車両に近づいている場合或いは車間距離はあるが相対速度がマイナス側に非常に大きい場合において、セットスイッチのＯＮ（図１３中（Ａ−３））により先行車追従制御の開始直後にスロットルイニシャル制御をそのまま実施し、本来のスロットル開度までスロットルバルブを一旦開いてしまうと（図１３中（Ａ−２）のＢ点）、先行車追従制御を開始した直後から減速する必要があるのにもかかわらず、不要な加速を呈してしまう（図１３中（Ａ−１）のＣ点）。
【００９２】
これに対して、本発明を適用した走行速度制御装置では、同様な状況において、セットスイッチのＯＮが検出されても（図１３中（Ｂ−３））、先行車追従制御の開始直後にはスロットルイニシャル制御を行わない、或いはスロットルイニシャル制御を行うがその影響を抑えるので（図１３中（Ｂ−２））、先行車追従制御の開始直後から減速するようになる（図１３中（Ｂ−１））。
【００９３】
また逆に、自車両が先行車両からかなり離れている場合或いは相対速度がプラス側に非常に大きい場合において、セットスイッチのＯＮ（図１４中（Ａ−３））により先行車追従制御の開始直後にスロットルイニシャル制御をそのまま実施し、本来のスロットル開度までスロットルバルブを一旦開いてしまうと（図１４中（Ａ−２）のＤ点）、車速制御により再び加速するため（図１４中（Ａ−２）のＥ点）、加速が二段階になってしまう図１４中（Ａ−１））。
【００９４】
これに対して、本発明を適用した走行速度制御装置では、同様な状況において、セットスイッチのＯＮが検出されても（図１４中（Ｂ−３））、その状況（車間距離や相対車速）に応じて先行車追従制御の開始直後のスロットルイニシャル制御を補正するので（図１４中（Ｂ−２））、先行車追従制御の開始直後から円滑に加速していくようになる（図１４中（Ｂ−１））。
【００９５】
以上、本発明の実施の形態を具体的に説明したが、前述の実施の形態に限定されないことはいうまでもない。
すなわち、前述の実施の形態では、スロットルイニシャル制御の補正を、目標スロットル開度初期値Ｔ_ｖｏｒｉを補正することにより実施している場合について説明したが、これに限定されるものではない。例えば、スロットルイニシャル制御の他の制御目標値、例えば目標駆動力初期値Ｆ_ｏｒｉや目標エンジントルク初期値Ｔ_ｅｒｉを補正することで、スロットルイニシャル制御の補正を実施するようにしてもよい。これによっても、同様な効果を得ることができる。
【００９６】
また、前述の実施の形態では、車間距離及び相対速度の両方の情報に基づいてスロットルイニシャル制御を補正する場合について説明したが、車間距又は相対速度のうちの少なくとも一方の情報に基づいてスロットルイニシャル制御を補正するようにしてもよい。
また、前述の実施の形態では、スロットルイニシャル制御についてする補正を第１の補正方法及び第２の補正方法として具体的に説明したが、この具体例に限定されないことはいうまでもない。さらに、その補正の実現手段である補正部４７及び増減率マップ部４８を車速制御部４０に設けた場合を説明したが、他の構成内に設けてもよく、或いはコントロールユニット内において独立して構成してもよい。
【００９７】
さらに、スロットルイニシャル制御の設定については、スロットルイニシャル制御で使用する本来の制御目標値を補正して実現することに限定されるものではない。例えば、車間距離や相対速度に基づいて何らかの演算式により、本来の制御目標値とは無関係に新たな制御目標値を得て、この制御目標値に基づいてスロットルイニシャル制御を実施してもよい。
また、各種処理部は回路として実現してもよく、マイクロコンピュータのソフトウェア形態により実現してもよい。
【図面の簡単な説明】
【図１】本発明の実施の形態の走行速度制御装置の一例を示す車両概略構成図である。
【図２】前記走行速度制御装置の構成を示すブロック図である。
【図３】前記走行速度制御装置の先行車追従制御部の構成を示すブロック図である。
【図４】前記先行車追従制御部の目標車間距離演算用定数決定部の構成を示すブロック図である。
【図５】前記走行速度制御装置の車速制御部の構成を示すブロック図である。
【図６】エンジン非線形定常特性マップを示す特性図である。
【図７】前記走行速度制御装置のスロットル制御部の構成を示すブロック図である。
【図８】補償前駆動信号（Ｄｕｔｙ比）指令値Ｄｕｔｙ＿Ｒ（ｔ）とバキューム（ＶＡＣ）／ベント（ＶＥＮＴ）駆動信号Ｄｕｔｙ（ｔ）との関係からなるマップを示す特性図である。
【図９】スロットルアクチュエータの構成を示す図である。
【図１０】車間距離偏差ΔＬ及び相対速度ΔＶに基づいてスロットル初期化量増減率を求めことができるマップを示す図である。
【図１１】走行速度制御装置の処理手順を示すフローチャートである。
【図１２】スロットルイニシャル制御の説明に使用した図である。
【図１３】自車両が先行車両に近づいた状態或いは車間距離は離れているが相対速度がマイナス側に非常に大きい状態である場合の本発明の効果の説明に使用した図である。
【図１４】自車両が先行車両からかなりはなれた状態或いは相対速度がプラス側に非常に大きい状態である場合の本発明の効果の説明に使用した図である。
【符号の説明】
１　エンジン
２　自動変速機
３　車間距離センサ
４　走行速度センサ
５　走行速度コントロールユニット
７　スロットルアクチュエータ
８　ブレーキアクチュエータ
１１　測距信号処理部
１２　走行速度信号処理部
１３　ブレーキ制御部
１４　変速比制御部
２０　走行車追従制御部
４０　車速制御部
４５　スロットル開度指令値算出部
４７　補正部
４８　増減率マップ部
６０　スロットル制御部
７０　スロットルアクチュエータ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a traveling speed control device and a traveling speed control method for controlling the traveling speed of a host vehicle so that the host vehicle follows a preceding vehicle.
[0002]
[Prior art]
As a traveling speed control device, there is a traveling speed control device described in JP-A-9-207616. The running speed control device described in Japanese Patent Application Laid-Open No. 9-207616 discloses a traveling speed control device which is connected to a throttle valve via a wire so that a throttle opening corresponding to a set vehicle speed is changed from a fully closed state at the start of constant speed control. The throttle initial control for driving the connected throttle actuator is performed. When using a negative pressure actuator as the throttle actuator, this throttle initial control opens the throttle valve at the maximum opening speed of the throttle actuator up to the throttle opening required for initialization processing at the start of control to maintain the set vehicle speed. However, smooth start of vehicle speed control has been realized.
[0003]
[Problems to be solved by the invention]
By the way, in the preceding vehicle following control device, the vehicle speed of the own vehicle is controlled according to the inter-vehicle distance between the preceding vehicle and the own vehicle or the relative speed that is a difference between the running speed of the preceding vehicle and the running speed of the own vehicle. Things are known. By combining the preceding vehicle follow-up control with the above-described throttle initial control technique, the following becomes possible.
[0004]
At the start of the preceding vehicle following control, the own vehicle is approaching the preceding vehicle (the inter-vehicle distance is relatively short) or the inter-vehicle distance is present but the relative speed is very large in the negative direction (the own vehicle approaches the preceding vehicle). In such a case, it is possible to execute the throttle initial control, then perform the deceleration control by the vehicle speed control, and then follow the preceding vehicle by the constant speed control.
[0005]
Conversely, when the host vehicle is far away from the preceding vehicle or the relative speed is very large on the plus side (the host vehicle is moving away from the preceding vehicle), the throttle initial control is performed, and It is possible to perform acceleration control by vehicle speed control and then follow a preceding vehicle by constant speed control.
However, simply combining the above-described throttle initial control and preceding vehicle follow-up control has the following problems.
[0006]
If the host vehicle is approaching the preceding vehicle or the inter-vehicle distance is present but the relative speed is extremely large on the negative side, the throttle valve will be once opened to the required throttle opening degree by executing the throttle initial control. Thus, there is a problem in that although the vehicle needs to be decelerated immediately after starting the vehicle speed control for the preceding vehicle following control, unnecessary acceleration is exhibited. For example, such behavior gives the driver an uncomfortable feeling.
[0007]
On the other hand, when the host vehicle is far away from the preceding vehicle or the relative speed is extremely large in the positive direction, the throttle valve is once opened to a necessary throttle opening degree by performing the throttle initial control, so that the vehicle is accelerated. After the acceleration by the throttle initial control, the vehicle is accelerated again by the original control of the preceding vehicle following control, so that there is a problem that the acceleration is performed in two stages. In addition, such behavior also gives the driver an uncomfortable feeling.
[0008]
As described above, the preceding vehicle follow-up control performs a specific control at the time of the start thereof, so that a problem occurs if the throttle initial control is simply combined.
Therefore, the present invention has been made in view of the above problem, and even when a function of performing a throttle initial control for temporarily increasing the throttle opening at the start of the preceding vehicle following control is provided, the preceding vehicle following control is smoothly performed. It is an object of the present invention to provide a traveling speed control device and a driving speed control method capable of starting the vehicle speed control by the vehicle.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the traveling speed control device according to the first aspect of the present invention increases the throttle opening once at the start of vehicle speed control that controls the traveling speed of the own vehicle so that the own vehicle follows the preceding vehicle. A travel speed control device having a throttle initial control function for causing the vehicle to run based on at least one of a distance between the preceding vehicle and the own vehicle or a relative speed that is a difference between the running speed of the preceding vehicle and the running speed of the own vehicle. And setting means for setting the throttle initial control.
[0010]
A traveling speed control device according to a second aspect of the invention is the traveling speed control device according to the first aspect, wherein the setting means corrects a control target value of the throttle initial control. I have.
Further, in the traveling speed control device according to the third aspect of the present invention, in the traveling speed control device according to the first aspect of the invention, the setting means may be configured such that when the inter-vehicle distance is smaller than a reference distance or when the relative speed is reduced. The throttle initial control is not performed when it is detected that the own vehicle is approaching the preceding vehicle based on the throttle initial control.
[0011]
Further, in the traveling speed control device according to the fourth aspect of the present invention, in the traveling speed control device according to the first aspect of the invention, when the inter-vehicle distance is smaller than a reference distance or when the relative speed is increased. When it is detected that the own vehicle is approaching the preceding vehicle based on this, the amount of increase in the throttle opening executed by the throttle initial control is suppressed.
[0012]
Also, in the traveling speed control device according to the invention described in claim 5, in the traveling speed control device according to the invention described in claim 1, the setting means determines whether the inter-vehicle distance is larger than a reference distance or the relative speed. When it is detected that the own vehicle is moving away from the preceding vehicle based on this, the amount of increase in the throttle opening executed by the throttle initial control is increased.
[0013]
According to a sixth aspect of the present invention, in the traveling speed control apparatus according to any one of the first to fifth aspects, the setting means is configured to determine the distance between the vehicles based on a map prepared in advance. The throttle initial control is set by obtaining an increase / decrease rate corresponding to the distance or the relative speed, and multiplying the obtained increase / decrease rate by a throttle opening performed by the throttle initial control.
[0014]
According to a seventh aspect of the present invention, there is provided a running speed control method for controlling the running speed of the own vehicle to perform a throttle initial control for once increasing the throttle opening at the start of the vehicle speed control for causing the own vehicle to follow the preceding vehicle. In the running speed control method, the throttle initial control is set based on at least one of an inter-vehicle distance between the preceding vehicle and the own vehicle or a relative speed that is a difference between the running speed of the preceding vehicle and the running speed of the own vehicle. It is characterized by:
[0015]
Further, in the running speed control method according to the invention described in claim 8, in the running speed control method according to the invention described in claim 7, the setting of the throttle initial control is performed by correcting a control target value of the throttle initial control. It is characterized by doing.
Further, the traveling speed control method according to the ninth aspect of the present invention is the traveling speed control method according to the seventh aspect, wherein the own vehicle is controlled based on the relative speed when the inter-vehicle distance is smaller than a reference distance. When it is detected that the vehicle is approaching the preceding vehicle, the throttle initial control is set by not performing the throttle initial control.
[0016]
The traveling speed control method according to a tenth aspect of the present invention is the traveling speed control method according to the seventh aspect of the present invention, wherein the vehicle is controlled based on the relative speed when the inter-vehicle distance is smaller than a reference distance. When it is detected that the vehicle is approaching the preceding vehicle, the throttle initial control is set by suppressing the amount of increase in the throttle opening performed in the throttle initial control.
[0017]
The traveling speed control method according to the invention of claim 11 is the traveling speed control method according to the invention of claim 7, wherein the own vehicle is arranged based on the relative speed when the inter-vehicle distance is larger than a reference distance. When it is detected that the vehicle is moving away from the preceding vehicle, the throttle initial control is set by increasing the amount of increase in the throttle opening performed in the throttle initial control.
[0018]
According to a twelfth aspect of the present invention, there is provided the traveling speed control method according to any one of the seventh to eleventh aspects, wherein the inter-vehicle distance or the relative speed is obtained from a map prepared in advance. And setting the throttle initial control by multiplying the increase / decrease rate by the throttle opening executed by the throttle initial control.
[0019]
Here, in vehicle speed control for controlling the traveling speed of the own vehicle to follow the preceding vehicle, that is, so-called preceding vehicle follow-up control, the traveling speed of the own vehicle is determined to be an optimum value based on the inter-vehicle distance and the relative speed.
According to the first and sixth aspects of the invention, the throttle initial control to be performed at the start of the preceding vehicle following control is set based on the inter-vehicle distance and the relative speed for determining the traveling speed in the preceding vehicle following control. are doing. According to the second and seventh aspects of the present invention, the setting is realized by correcting the control target value used in the throttle initial control.
[0020]
At the start of the preceding vehicle following control, control is performed to reduce the speed when the following distance is short or the own vehicle approaches the preceding vehicle, and conversely, when the following distance is long or the own vehicle moves away from the preceding vehicle. In such a case, acceleration control is performed.
According to the third, fourth, ninth and tenth aspects of the present invention, when the inter-vehicle distance is smaller than the reference distance, the throttle initial control is performed under such characteristics of the preceding vehicle following control. When it is detected that the own vehicle is approaching the preceding vehicle based on the relative speed, the throttle initial control is not performed, and even when the throttle initial control is performed, the amount of increase in the throttle opening is suppressed. I have. On the other hand, in the inventions according to claims 5 and 11, when the inter-vehicle distance is larger than the reference distance or when it is detected that the own vehicle is moving away from the preceding vehicle based on the relative speed, the increase amount of the throttle opening is increased. I try to increase.
[0021]
【The invention's effect】
As described above, according to the present invention, by setting the throttle initial control based on at least one of the inter-vehicle distance and the relative speed, the throttle initial control is effectively performed at the start of the preceding vehicle follow-up control, and unnecessary acceleration is performed. Can be eliminated. As a result, the driver does not feel uncomfortable when starting the preceding vehicle following control.
[0022]
In particular, according to the third, fourth, fifth, ninth, tenth, and eleventh aspects of the invention, the effect is achieved by setting the throttle initial control in accordance with the specific control characteristic at the start of the preceding vehicle following control. Can be more effective.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram showing a traveling speed control device to which the present invention is applied. In the figure, reference numeral 1 denotes an engine as a driving source, and reference numeral 2 denotes an automatic transmission for converting the driving force of the engine. Reference numeral 3 denotes an inter-vehicle distance sensor capable of detecting an object in front of the host vehicle by using a laser, a radio wave, or the like and detecting a distance to the object. Reference numeral 4 denotes a traveling speed sensor that detects the traveling speed of the vehicle. For example, the vehicle speed sensor 4 detects the output shaft rotation speed of the automatic transmission 2. Reference numeral 5 also controls the traveling speed of the host vehicle, that is, the driving force and the braking force, such that the inter-vehicle distance detected by the inter-vehicle distance sensor 3 becomes, for example, a target inter-vehicle distance corresponding to the traveling speed of the own vehicle. Running speed control unit. Reference numeral 6 denotes a throttle actuator for controlling the operation state of the engine 1, reference numeral 7 denotes a transmission actuator for controlling a speed ratio of the automatic transmission 2, and reference numeral 8 denotes a depression of a brake pedal. Are brake actuators for individually controlling the braking force of each wheel, and the operation state is controlled in accordance with a command value (command signal) from the traveling speed control unit 5, respectively.
[0024]
FIG. 2 is a block diagram showing a configuration of the traveling speed control device. The traveling speed control device inputs a traveling speed and an inter-vehicle distance, and outputs a traveling speed.
That is, the inter-vehicle distance detected by the inter-vehicle distance sensor 3 is signal-processed by the distance measurement signal processing unit 11 and is calculated as the inter-vehicle distance (L) from the own vehicle to the front object, more specifically, to the preceding vehicle. . Further, the ranging signal processing unit 11 calculates a relative speed (ΔV) which is a difference between the traveling speed of the host vehicle and the traveling speed of the preceding vehicle. Here, the relative speed is calculated by differentiating the calculated inter-vehicle distance, or the inter-vehicle distance is obtained through a band-pass filter. Then, the ranging signal processing unit 11 outputs the calculated inter-vehicle distance and relative speed to the preceding vehicle following control unit 20 and the vehicle speed control unit 40, respectively.
[0025]
On the other hand, the traveling speed detected by the traveling speed sensor 2 is signal-processed by the traveling speed signal processing unit 12, and is calculated as the traveling speed (V) of the own vehicle. The traveling speed signal processing unit 12 outputs the calculated traveling speed to each of the preceding vehicle following control unit 20 and the vehicle speed control unit 40.
The preceding vehicle following control unit 20 sets a target inter-vehicle distance based on the inter-vehicle distance, the traveling speed, and the relative speed, and sets a target traveling speed from the target inter-vehicle distance, inter-vehicle distance, and traveling speed. A control signal is output to the vehicle speed control unit 40 so as to perform the control. The configuration of the preceding vehicle following control unit 20 will be described later in detail.
[0026]
The vehicle speed control unit 40 calculates a target driving force (including a target braking force) based on the target traveling speed and the actual traveling speed, divides the target driving force into a driving force and a braking force, and uses them for throttle control. Output to the unit 60 and the brake control unit 13. The vehicle speed control unit 40 can be configured using various methods such as a feedback control method and a robust model matching control method disclosed in Japanese Patent Application Laid-Open No. 10-272963. The configuration of the vehicle speed control unit 40 will be described later in detail.
[0027]
The throttle control unit 60 is configured to adjust the throttle actuator 70 in accordance with the throttle opening command value. The throttle control unit 60 controls the throttle actuator 70 so that a given driving force (or braking force by an engine brake) is achieved. Output drive signal. Further, the brake control unit 13 is configured to adjust the brake fluid pressure according to the brake fluid pressure command value, and outputs a drive signal to the brake actuator 8 so that the given braking force is achieved. Further, the speed ratio control unit 14 is configured to adjust the speed ratio of the transmission according to the speed ratio command value, and outputs a drive signal to the transmission actuator 7 to set the speed ratio to a predetermined value. . The transmission may be a stepped transmission or a continuously variable transmission.
[0028]
Next, details of the preceding vehicle following control unit 20, the vehicle speed control unit 40, the throttle control unit 60, and the throttle actuator 70 shown in FIG. 2 will be described.
First, the details of the preceding vehicle following control unit 20 will be described. In this embodiment, the vehicle speed command value V from the preceding vehicle following control unit 20 is used.^*Is input, and the transmission characteristic Gv (s) of the vehicle speed control system that outputs the own vehicle speed V detected by the traveling vehicle speed sensor 4 is approximated to a first-order lag system as shown in the following equation (1).
[0029]
Gv (s) = ωv / (s + ωv) (1)
Here, ωv is the corner angle frequency of the transfer coefficient of the vehicle speed control unit 40.
FIG. 3 is a block diagram illustrating a configuration of the preceding vehicle following control unit 20 that realizes such transfer characteristics. The preceding vehicle following control unit 20 includes an inter-vehicle distance command value calculation unit 21, a target inter-vehicle distance calculation unit 22, a vehicle speed command value calculation unit 23, and a target inter-vehicle distance calculation constant determination unit 30.
[0030]
As described above, the inter-vehicle distance L and the relative speed ΔV from the distance measurement signal processing unit 11 and the own vehicle speed V from the traveling speed signal processing unit 12 are input to the preceding vehicle following control unit 20 having such a configuration. Have been.
The inter-vehicle distance command value calculation unit 21 calculates the inter-vehicle distance command value L based on the own vehicle speed V and the relative speed ΔV.^*Is calculated. Specifically, as a function of the traveling speed Vt of the preceding vehicle represented by the following equation (2), the following distance command value L^*Is calculated by the following equation (3).
[0031]
Vt = V + {V} (2)

Where a is a coefficient and L_ofIs an offset value. As can be seen from the relationship of equation (2), the following distance command value L^*May be calculated as a function of the vehicle speed V. In this case, the calculation is performed by the equation (4).
[0032]
L^*= A '· V + L_of・ ・ ・ (4)
Here, a 'is a coefficient. The inter-vehicle distance command value L^*May be a set value set by the occupant.
The following distance command value calculating unit 21 calculates the following distance command value L^*Is output to the target inter-vehicle distance calculation unit 22.
[0033]
On the other hand, the target inter-vehicle distance calculation constant determining unit 30 calculates the inter-vehicle distance command value L from the inter-vehicle distance command value calculation unit 21.^*Is an input and the inter-vehicle distance control system outputs the inter-vehicle distance L detected by the inter-vehicle distance sensor 3.^*In order to make the response characteristics of the inter-vehicle distance control until the vehicle arrives at an optimum response characteristic (hereinafter referred to as target inter-vehicle distance control response characteristic) according to the inter-vehicle distance deviation △ L and the relative speed △ V, Damping coefficient of the system ζ_TAnd natural frequency ω_TAre determined according to the inter-vehicle distance deviation ΔL and the relative speed ΔV.
[0034]
Here, the inter-vehicle distance deviation ΔL is given by the following equation (5).
ΔL = LL^*・ ・ ・ (5)
Specifically, the damping coefficient of the inter-vehicle distance control system according to the inter-vehicle distance deviation △ L and the relative speed △ V so that the optimal inter-vehicle distance control response characteristic is obtained in various following situations._TAnd natural frequency ω_TAre set in advance as a map, and a damping coefficient 対 応 corresponding to the inter-vehicle distance deviation △ L and the relative speed △ V during the follow-up control ζ_TAnd natural frequency ω_TAre determined as constants for calculating the target inter-vehicle distance.
[0035]
FIG. 4 shows a configuration example of a target inter-vehicle distance calculation constant determining unit 30 that realizes such processing. The target inter-vehicle distance calculation constant determining unit 30 calculates the inter-vehicle distance L and the inter-vehicle distance command value L.^*An inter-vehicle distance deviation calculating unit 31 that calculates an inter-vehicle distance deviation ΔL based on_TAnd natural frequency ω_TAnd a natural frequency ω based on the map of the map unit 32 based on the relative speed ΔV and the inter-vehicle distance deviation ΔL._TAnd a damping coefficient ζ based on the map unit of the map unit 32 based on the relative speed ΔV and the inter-vehicle distance deviation ΔL._TAnd an inter-vehicle distance command value calculation unit 34 for calculating
[0036]
The target inter-vehicle distance calculation constant determining unit 30 having the above-described configuration determines the determined damping coefficient ζ_TAnd natural frequency ω_TIs output to the target inter-vehicle distance calculation unit 22.
The target inter-vehicle distance calculation unit 22 calculates the attenuation coefficient ζ from the inter-vehicle distance command value calculation unit 34._TAnd natural frequency ω_T, The inter-vehicle distance command value L^*Is passed through a secondary type filter shown in the following equation (6) to obtain the target following distance L_TAnd target relative speed ΔV_TIs calculated. In addition, the following distance L immediately after recognizing the preceding vehicle₀And relative speed ΔV₀And are set to initial values.
[0037]
(Equation 1)

[0038]
The target inter-vehicle distance L calculated by the equation (6)_TAnd target relative speed ΔV_TMeans that the actual inter-vehicle distance L becomes the inter-vehicle distance command value L through the target inter-vehicle distance control response characteristic.^*The final inter-vehicle distance command value that defines the temporal transition of the inter-vehicle distance deviation ΔL and the relative speed ΔV so as to converge to the following is shown.
When this equation (6) is expanded and Laplace transformed, it can be expressed as the following equation (7).
[0039]
L_T(S) / L^*(S) = ω_T ²/ (S²+ 2ζ_Tω_Ts + ω_T ²) ・ ・ ・ (7)
This equation (7) is used to calculate the inter-vehicle distance command value L.^*Target inter-vehicle distance L_TAnd is represented by a quadratic equation. In this embodiment, in the inter-vehicle distance control system, the actual inter-vehicle distance L is the target inter-vehicle distance L expressed by the above equation (7)._T(The final inter-vehicle distance command value) is subjected to feedback control. As described above, the damping coefficient of the inter-vehicle distance control system ζ_TAnd natural frequency ω_TSince a value at which a target inter-vehicle distance control response is obtained according to the inter-vehicle distance deviation △ L and the relative speed △ V is set, a desired inter-vehicle distance control response can be realized in various following situations.
[0040]
Note that the target inter-vehicle distance control response characteristic includes a sudden deceleration when the relative speed with the preceding vehicle is small even when the inter-vehicle distance with the preceding vehicle is smaller than the inter-vehicle distance command value in an interrupting scene, an overtaking scene, or the like. And a response is desired such that the actual inter-vehicle distance slowly converges to the inter-vehicle distance command value. In addition, even when the relative speed is large in an approaching scene or the like, if the inter-vehicle distance is long, rapid response is not performed, and a response in which the inter-vehicle distance slowly converges to the command value is desirable. In such a following situation, the actual inter-vehicle distance has a secondary response characteristic such that the command value converges after overshooting or undershooting the command value, and such a response is expressed by the above equations (6) and (7). It can be realized by a secondary filter.
[0041]
The target inter-vehicle distance calculation unit 22 outputs the inter-vehicle distance deviation ΔL and the relative speed ΔV obtained in this way to the vehicle speed command value calculation unit 23.
The vehicle speed command value calculator 23 calculates a predetermined constant f_V, F_LAnd the vehicle speed command value V by the following equation (8).^*Is calculated, and the obtained vehicle speed command value V^*Is output to the vehicle speed control unit 40.
V^*= V (t) + △ V (t)-｛f_V(△ V_T(T)-△ V (t)) + f_L(L_T(T) -L (t))｝ (8)
Where f_VIs the target relative speed deviation (target relative speed △ V_T(T) and the relative speed detection value ΔV (t), (ΔV_T(T)-{V (t)))} and f_LIs the target inter-vehicle distance deviation (the target inter-vehicle distance L_T(T) and a difference between the detected inter-vehicle distances L (t), (L_T(T) -L (t))).
[0042]
The above is the details of the configuration of the preceding vehicle following control unit 20. If the preceding vehicle cannot be detected by the inter-vehicle distance sensor 3, the preceding vehicle following control unit 20 sets the vehicle speed set by the occupant as the target vehicle speed to the vehicle speed command value V.^*Is output to the vehicle speed control unit 40.
Next, details of the vehicle speed control unit 40 will be described.
The vehicle speed control unit 40 calculates the vehicle speed command value V_COM(T) and own vehicle speed V_A(T) and input the drive torque command value d_FC(T) is calculated. Here, the vehicle speed command value V_COM(T) is the vehicle speed command value V^*Corresponding to the value at each time t,_A(T) corresponds to the value of the vehicle speed V at each time t.
[0043]
FIG. 5 shows a configuration example of the vehicle speed control unit 40. The vehicle speed controller 40 includes a model matching compensator 41, a disturbance estimator 42, a brake pressure command value calculator 43, an engine torque command value calculator 44, a throttle opening command value calculator 45, and a gear ratio command value calculator. A unit 46, a correction unit 47, and an increase / decrease rate map unit 48 are provided.
In the vehicle speed control unit 40, the vehicle speed command value V_COM(T) as input, and own vehicle speed V_A(T) as an output, and in this case, its transfer characteristic G_V(S) can be represented by the following equation (9).
[0044]
G_V(S) = 1 / (T_V・ S +1) ・ e^{-Lv · s}・ ・ ・ (9)
Where T_VIs the first-order lag time constant, and L_VIs a dead time due to a delay in the power train system.
Further, the vehicle model to be controlled is changed to a drive torque command value d._FC(T) is the operation amount, and the vehicle speed V_ABy modeling (t) as a control amount, the behavior of the vehicle power train can be represented as a simplified linear model represented by the following equation (10).
[0045]
V_A(T) = 1 / (m_V・ Rt ・ s) ・ e^{-Lv · s}・ D_FC(T) ... (10)
Here, Rt is the effective turning radius of the tire, and m_VIs the vehicle mass.
The drive torque command value d as shown in the equation (10)_FC(T) as input, and own vehicle speed V_AA vehicle model that outputs (t) has an integral characteristic because it has a form of 1 / s.
[0046]
It should be noted that the characteristic of the control object has a dead time L due to the delay of the power train system._VAnd the dead time L depends on the actuator and engine used._VBy using a disturbance estimator based on an approximate zeroing model for the nonlinear characteristic in which the value of_FC(T) as input, and own vehicle speed V_AThe vehicle model that outputs (t) can be expressed by the same equation as above.
[0047]
Here, the vehicle speed command value V_COM(T) as input, and own vehicle speed V_AThe response characteristic of the control target when (t) is output is determined by a predetermined primary delay T_HAnd dead time L_VSpecialized G with element_V(S 特定), the compensator C constituting the model matching compensator 41 shown in FIG.₃(S) Compensator C constituting disturbance estimator section 42₁(S), C₂Using (s), it can be determined as follows. Note that compensator C₁(S), C₂(S) employs an approximate zeroing technique to constitute the disturbance estimator 42, and these compensators C₁(S), C₂(S) functions to suppress the effects of disturbances and model change errors.₃(S) configures the model matching compensator unit 41 by employing the model matching method.
[0048]
Compensator C constituting disturbance estimator section 42₁(S), C₂(S) can be expressed as the following equations (11) and (12), respectively.
C₁(S) = e^{-Lv · s}/ (T_V・ S + 1) ・ ・ ・ (11)
C₂(S) = (m_v・ Rt · s) / (T_V・ S + 1) ・ ・ ・ (12)
Such a compensator C₁(S), C₂(S), the disturbance estimate d_V(T) is represented by the following equation (13).
[0049]
d_V(T) = C₂(S) · V_A(T) -C₁(S) · d_FC(T) ... (13)
Further, ignoring the dead time of the control object, the reference model G_V(S) is the time constant T_V, A compensator C constituting the model matching compensator section 41₃(S) can be expressed as the following equation (14).
[0050]
C₃(S) = m_V・ Rt / T_V・ ・ ・ (14)
Compensator C as described above₁(S), C₂(S), C₃(S), the drive torque command value d_FC(T) is calculated as the following equation (15).
d_FC(T) = C₃(S) · ｛VC_COM(T) -V_A(T)｝-｛C₂(S) · V_A(T) -C₁(S) · d_FC(T)｝ ... (15)
In the engine torque command value calculation unit 44, the drive torque command value d_FC(T) and the actual gear ratio RATIO (t) based on the engine torque command value TE._COM(T) is calculated by the following (16).
[0051]
TE_COM(T) = d_FC(T) / {Gf · RATIO (t)} (16)
Here, Gf is a final gear ratio.
Then, the throttle opening command value calculation unit 45 calculates the engine torque command value TE._COMTarget throttle opening TVO from the full engine performance map based on (t) and the engine speed Ne (t)._COM(T) is calculated. FIG. 6 is an engine non-linear steady-state characteristic map, which is an example of the full engine performance map, showing the relationship between the engine torque and the throttle opening using the engine rotation speed as a parameter. Command value TE_COM(T) and the target throttle opening TVO based on the engine speed Ne (t)._COM(T) is obtained. Then, the throttle opening command value calculation unit 45 calculates the target throttle opening TVO_COM(T) is output to the throttle control unit 60.
[0052]
The correction unit 47 and the increase / decrease rate map unit 48 are configured to correct the throttle initial control performed at the start of the preceding vehicle following control, and will be described later in detail.
The above is the details of the configuration of the vehicle speed control unit 40.
Next, details of the throttle control unit 60 will be described. The throttle control unit 60 controls the target throttle opening TVO_COM(T) is input, and a drive signal command value Duty (t) corresponding to the input is output to the throttle actuator 70. FIG. 7 shows a configuration example of the throttle control unit 60 that realizes such processing. The throttle control unit 60 includes a model matching compensator 61, a disturbance estimator 62, and a non-linear compensator 63.
[0053]
Here, the control model of the throttle actuator 70 to be controlled is modeled using the pre-compensation drive signal (duty ratio) command value Duty_R (t) as an operation amount and the throttle opening equivalent TVO (t) as a control amount. Thus, it is represented as a simple linear model represented by the following equation (17).
TVO (t) = (ka / s). e^{-La · s}-Duty_R (t) (17)
Here, ka is an integral gain (opening / closing speed at 100% duty), and La is a dead time.
[0054]
As described above, the control model that receives the compensation precursor signal (duty ratio) command value Duty_R (t) and outputs the throttle opening equivalent TVO (t) has a 1 / s form, and thus has an integral characteristic. You can see that.
The characteristic of the control target has a non-linear characteristic in which the dead time La changes depending on the throttle actuator 70 used. As will be described later, by using a disturbance estimator using an approximate zeroing method, the drive signal before compensation (duty ratio ) A control model in which the command value Duty_R (t) is input and the throttle opening equivalent TVO (t) is output can be expressed by the same equation as the above equation.
[0055]
Here, the response characteristic of the control target when the pre-compensation drive signal (Duty ratio) command value Duty_R (t) is input and the throttle opening equivalent TVO (t) is output is a predetermined first order delay Ta or When matched with the transfer characteristic Ga (s) having an element such as the dead time La, the compensator C constituting the model matching compensator 61 shown in FIG.₆(S) Compensator C constituting disturbance estimator unit 62₄(S), C₅Using (s), it can be determined as follows. Note that compensator C₄(S), C₅(S) configures the disturbance estimator section 62 by employing the approximate zeroing method, and these compensators C₄(S), C₅(S) functions to suppress the effects of disturbances and model change errors.₆(S) configures the model matching compensator unit 61 by employing the model matching method.
[0056]
Compensator C constituting disturbance estimator unit 62₄(S), C₅(S) can be expressed as the following equations (11) and (12), respectively.
C₄(S) = e^{-La · s}/ (T_a・ S + 1) ・ ・ ・ (18)
C₅(S) = s / ｛(ka · (T_a・ S + 1)｝ ・ ・ ・ (19)
Such a compensator C₄(S), C₅(S), the disturbance estimate d_Va(T) is represented by the following equation (20).
[0057]

Further, ignoring the dead time of the control object, the reference model is set to have the time constant T_b, The compensator C that constitutes the model matching compensator 61₆(S) is represented by the following equation (21).
[0058]
C₆(S) = 1 / (ka · T_b) ・ ・ ・ (21)
Compensator C as described above₄Based on (s), C5 (s), and C6 (s), the pre-compensation drive signal (duty ratio) command value Duty_R (t) is calculated as the following equation (22).

Further, when a negative pressure type actuator is used as the throttle actuator 70, it is easily affected by non-linear factors such as friction at the time of ON / OFF of a vacuum motor for generating a negative pressure and at the time of opening / closing of a vent valve. Therefore, the non-compensation drive signal (Duty ratio) command value Duty_R (t) calculated as described above is subjected to non-linear compensation using the map shown in FIG. A VAC / vent drive signal Duty (t) is obtained, and this value is output to the throttle actuator 70.
[0059]
Here, the non-linear compensation map is a map for calculating the VAC / VENT drive signal Duty (t) from the pre-compensation drive signal (Duty ratio) command value Duty_R (t), as shown in FIG. For example, the map is such that a vacuum motor drive signal is output when Duty_R (t) ≧ 0, and a vent valve drive signal is output when Duty_R (t) <0.
[0060]
Although the negative pressure type actuator operates using a negative pressure as a power source, the negative pressure may be generated by driving a vacuum motor, or may be generated by using a negative pressure of an intake pipe. . Further, in the negative pressure type actuator, the drive is performed so that the throttle is opened at the time of vacuum (VAC) and the throttle is closed at the time of vent (VENT).
[0061]
Here, the configuration of the throttle actuator 70 as a negative pressure type actuator will be described. FIG. 9 shows a configuration example of the throttle actuator 70.
The throttle actuator 70 is roughly composed of an actuator 71, a vacuum pump 72, a vent valve 73, and a safety valve 74, and a vent valve 73 and a safety valve are provided in the middle of a pipe connecting the actuator 71 and the vacuum pump 72. 74 are arranged.
[0062]
In the actuator 71, a negative pressure chamber 71a is defined by a diaphragm 71b, and an accelerator wire 71c connected to a throttle valve is attached to the diaphragm 71b. The vacuum pump 72 is configured to drive a diaphragm 72b by a motor 72a to make a negative pressure in a negative pressure chamber 71a of the actuator 71. The bend valve 73 and the safety valve 74 are for releasing the negative pressure of the negative pressure chamber 71a of the actuator 71 to the atmospheric pressure, and the vent valve 73 is driven by controlling the vent valve solenoid 73a. The safety valve 74 is driven by controlling the vacuum pump motor 74a. The safety valve 74 communicates with the atmosphere, and functions to release the vehicle speed control or stop the vehicle speed control when any abnormality is detected.
[0063]
In such a throttle actuator 70, by appropriately driving the vacuum pump 72 and the vent valve 73, the diaphragm 71b of the actuator 71 is moved (moves in the left-right direction in FIG. 9) according to the negative pressure, and is connected to the diaphragm 71b. The throttle valve is opened and closed via the accelerator wire 71c.
[0064]
Accordingly, the vehicle speed control unit 40 constituting the control unit 100 outputs the throttle opening command value to the throttle control unit 60, and is configured as described above via the throttle control unit 60 and the signal line 101. The vacuum pump 72, vent valve 73, and safety valve 74 of the throttle actuator 70 are appropriately controlled to adjust the throttle valve of the engine. The throttle opening command value output by the throttle control unit 60 via the signal line 101 corresponds to the vacuum (VAC) drive signal Duty (t) or the vent (VENT) drive signal Duty (t).
[0065]
The above is the description of the overall configuration of the traveling speed control device and the preceding vehicle follow-up control unit 20, the vehicle speed control unit 40, the throttle control unit 60, and the throttle actuator 70 that constitute the traveling speed control device.
The traveling speed control device is capable of correcting the throttle initial control by applying the present invention, which will be described below.
[0066]
The throttle initial control is, as described above, a vehicle speed for smoothly connecting a throttle fully closed state to a throttle opening corresponding to a set vehicle speed, as disclosed in, for example, JP-A-9-207616. This is the initial control of the control. According to the application of the present invention, the traveling speed control device executes such a throttle initial control at the start of the preceding vehicle following control, so that the own vehicle is approaching the preceding vehicle (inter-vehicle distance is relatively short) or When there is an inter-vehicle distance, but the relative speed is extremely large on the minus side (state in which the own vehicle approaches the preceding vehicle), and conversely, when the own vehicle is far away from the preceding vehicle, or When the vehicle speed is extremely high on the plus side (the vehicle is moving away from the preceding vehicle), the throttle initial control to be performed is appropriately corrected. Specifically, the correction is performed as follows.
[0067]
As described above, the inter-vehicle distance L and the relative speed ΔV are measured by the preceding vehicle follow-up control unit 20, but as a correction of the throttle initial control, the throttle initial control for the throttle initial control is performed according to the inter-vehicle distance L and the relative speed ΔV. The control signal is being corrected. Here, a target throttle opening (hereinafter referred to as a target throttle opening initial value T) which is a control signal at the time of the throttle initial control calculated by the throttle opening command value calculating unit 45 of the vehicle speed control unit 40 is described._voriThat. ) Will be described with reference to a plurality of examples.
[0068]
First, in the first correction method, when the own vehicle is approaching the preceding vehicle based on the inter-vehicle distance L or the relative speed ΔV, or when the inter-vehicle distance is present but the relative speed is extremely large on the minus side, the target Throttle opening initial value T_voriIs set to 0. That is, normal vehicle speed control is started without performing the throttle initial control.
[0069]
Specifically, the correction unit 47 of the vehicle speed control unit 40 shown in FIG. 5 calculates the target throttle opening TVO calculated by the throttle opening command value calculation unit 45 for performing the normal throttle initial control._COM(T) the target throttle opening initial value T_voriTo 0.
Alternatively, as a second correction method, the change rate (T) is determined using a predetermined map based on the following distance L and the relative speed ΔV._voriaj), And as shown in the following equation (23), the target throttle opening initial value T is calculated._vori, And a method of setting a new initial target throttle opening value.
[0070]
T_vori= T_vori× T_voriaj・ ・ ・ (23)
For example, as the predetermined map, as shown in FIG. 10, an inter-vehicle distance deviation ΔL (= L−L^*) And the relative speed ΔV, the change rate T_voriajCan be determined. In this map, the larger the relative speed ΔV or the larger the inter-vehicle distance deviation ΔL, the higher the change rate T_voriajThe smaller the relative speed ΔV (the larger the negative value) or the smaller the inter-vehicle distance deviation ΔL (the larger the negative value), the lower the change rate T_voriajbecome.
[0071]
If such a map is used, when the vehicle is approaching the preceding vehicle or when there is an inter-vehicle distance but the relative speed is very large on the negative side, the change rate T_voriajBecomes low or becomes zero, so that the original target throttle opening initial value T_voriNew target throttle opening initial value T_voriIs determined to be a small value or 0. Conversely, if the host vehicle is far away from the preceding vehicle or the relative speed is very large on the positive side, the change rate T_voriajBecomes higher, the original target throttle opening initial value T_voriNew target throttle opening initial value T_voriIs determined to be a large value.
[0072]
Explaining this second correction method as a specific configuration, the correction unit 47 of the vehicle speed control unit 40 shown in FIG. 5 uses the throttle opening command value based on the map held in the increase / decrease rate map unit 48. Target throttle opening initial value T calculated by calculation unit 45_voriIs the change rate T_voriajWill be corrected.
According to the first and second correction methods as described above, when the inter-vehicle distance is smaller than the reference distance or when it is detected that the own vehicle is approaching the preceding vehicle based on the relative speed, the throttle executed by the throttle initial control. The correction is performed to suppress the amount of increase in the opening, and conversely, when the inter-vehicle distance is larger than the reference distance or when it is detected that the own vehicle is moving away from the preceding vehicle based on the relative speed, the adjustment is performed by the throttle initial control. A correction is made to increase the amount of increase in the throttle opening. Here, the reference distance is the inter-vehicle distance command value L.^*It is.
[0073]
As described above, in the traveling speed control device, the throttle initial control is appropriately corrected.
Next, a processing procedure at the time of vehicle speed control of the traveling speed control device will be described. FIG. 11 shows a flowchart of a main routine of the vehicle speed control. In this embodiment, the control of the traveling speed control device is realized by the microcomputer of the control unit, and the microcomputer of the control unit executes the processing procedure shown in FIG. 11 as a main routine for a predetermined time (for example, 100 msec). ing.
[0074]
First, in step S1, the actual vehicle speed Vsp and the engine speed Ne are calculated based on the measured values of the traveling speed sensor 4 and an engine speed sensor (not shown), and the actual throttle opening is measured by a throttle sensor (not shown).
Subsequently, in step S2, it is determined whether or not the cancel switch of the ASCD control (auto speed control) provided on the steering wheel or the like has been operated. Here, if the cancel switch has been operated, the process proceeds to step S19, the safety valve 74 is closed, and the process returns. If the cancel switch has not been operated, the process proceeds to step S3.
[0075]
The operation state of the cancel switch may be determined, and whether the foot brake is operated may be determined by the brake switch. That is, it is determined whether or not the foot brake is operated by the brake switch. If the foot brake is operated, the process proceeds to step S19, the safety valve 74 is closed, and the process returns.
[0076]
Here, the processing when the cancel switch is operated or when the foot brake is operated is, specifically, the release of the cruise control and the ASCD control indicating that the cruise control is being performed. This is a process for initializing the middle flag and various variables.
On the other hand, in step S3, it is determined whether an ASCD control set switch provided on the steering wheel or the like has been operated. Here, when the set switch is operated, that is, when the execution start command of the preceding vehicle following control is issued, the process proceeds to step S4, and when the set switch is not operated, the process proceeds to step S9.
[0077]
The processing shown in steps S4 to S8 is processing for throttle initial control, that is, here, correction processing of the throttle initial control as described above is also performed.
First, in step S4, the set vehicle speed is set and stored in the target vehicle speed Vspr, and in the following step S5, a running resistance R when the vehicle runs on a flat road at the target vehicle speed Vspr is obtained from a map previously stored in a memory. To the target driving force initial value F_oriTo be stored.
[0078]
Then, a target driving force initial value (or a target driving torque initial value) F_oriThe actuator output width initial value T which is the output pulse width initial value to the vacuum pump 72 necessary to obtain_vaciIs determined as follows.
First, in step S6, the target driving force initial value F_oriTarget engine torque initial value T using_eriIs calculated by the following equation (24). The calculation here is performed by the engine torque command value TE in the engine torque command value calculation section 44 of the vehicle speed control section 40._COMThis corresponds to the calculation of (t).
[0079]
T_eri= (F_ori・ Rt) / Gm ・ Gf ・ ・ ・ (24)
Here, Gm is the gear ratio of the transmission, and Rt is the effective radius of rotation of the tire.
Further, the target engine torque initial value T calculated in this way is_eriUsing the engine non-linear steady-state characteristic map shown in FIG._voriIs calculated. The calculation here is performed by the target throttle opening TVO in the throttle opening command value calculator 45 of the vehicle speed controller 40._COMThis corresponds to the calculation of (t).
[0080]
Then, based on the inter-vehicle distance L and the relative speed ΔV, the target throttle opening initial value T is obtained by the first correction method or the second correction method as described above._voriOf the throttle initial control by compensating.
That is, if the detection result of the inter-vehicle distance L and the relative speed ΔV indicates that the own vehicle is approaching the preceding vehicle or that the inter-vehicle distance is present but the relative speed is very large on the negative side, the target throttle opening Degree initial value T_voriTo zero. Alternatively, using the map, the original target throttle opening initial value T_voriNew target throttle opening initial value T_voriTo a small value. As a result, the throttle initial control is not performed, and the normal vehicle speed control is started.
[0081]
Conversely, if the detection result of the inter-vehicle distance L or the relative speed ΔV indicates that the own vehicle is far away from the preceding vehicle or the relative speed is extremely large on the positive side, the map is used. , The original target throttle opening initial value T_voriNew target throttle opening initial value T_voriTo a large value.
Then, in step S7, the target throttle opening initial value T is calculated by the following equation (25)._voriFrom the actuator output pulse width initial value T_vaciIs calculated.
[0082]
T_vaci= T_vori/ Ka + La (25)
Here, ka is an integral gain (opening / closing speed at 100% duty), and La is a dead time.
Thus, in steps S6 and S7, the target driving force initial value F_oriThe actuator output width initial value T which is the output pulse width initial value to the vacuum pump 72 necessary to obtain_vaciAfter that, in step 8, an ASCD control flag indicating that constant-speed running control is being performed and an initial flag indicating execution of throttle initial control are set, and the process returns.
[0083]
On the other hand, in step 9 which proceeds when the set switch has not been operated in step 3, it is determined whether or not the ASCD control flag is set. Here, if the ASCD control flag is not set, the process proceeds to step S19, the safety valve 74 is closed, and the process returns. If the ASCD control flag is set, the process proceeds to step S10.
[0084]
In step S10, it is determined whether or not the initial flag has been set. Here, if the initial flag has been set, the process proceeds to step S15, and if the initial flag has not been set, the process proceeds to step S11.
In step S11, a vehicle speed feedback control is performed to calculate a target driving force as a vehicle speed control calculation. In the following step S12, a target throttle opening is calculated from the target driving force. In the following step S13, the target throttle opening is calculated. Calculate the actuator output pulse width with the target value as. Then, in the following step S14, the vacuum (VAC) valve drive signal T is generated based on the actuator output pulse width._vacAnd vent (VENT) valve drive signal T_ventIs output to the vacuum pump 72 and the vent valve 73 of the throttle actuator 70.
[0085]
Here, the processing of steps S11 to S14 is realized by the arithmetic expressions specifically described with reference to FIGS. The processing in steps S11 to S14 is performed when the initial flag is not set, that is, the processing in the preceding vehicle following control after the execution of the throttle initial control.
[0086]
On the other hand, in step S15 where the initial flag is set in step S10, the safety valve 74 is closed, and the flow proceeds to step S16.
In step S16, the actuator output pulse width T_vaciIs not longer than 100 ms. Here, the actuator output pulse width T_vaciIs less than or equal to 100 ms, the routine proceeds to step 16, where it is determined that the initial setting of the throttle opening as the throttle initial control has been completed, the initial flag is cleared, and the routine proceeds to step S14. On the other hand, the actuator output pulse width T_vaciIs greater than 100 ms, the routine proceeds to step 18, where the actuator output pulse width T_vaciFrom the actuator output pulse width T_vaciAnd the process proceeds to step S14. And the actuator output pulse width T_vaci(VAC) valve drive signal T based on_vacAnd vent (VENT) valve drive signal T_ventAnd outputs this signal to the vacuum pump 72 and the vent valve 73 of the throttle actuator 70.
[0087]
The above is the configuration of the traveling speed control device and the processing contents (operation contents).
As described above, the traveling speed control device to which the present invention is applied has a state in which the own vehicle is approaching the preceding vehicle based on the inter-vehicle distance L and the relative speed ΔV at the time of starting the preceding vehicle following control, or there is a following distance. When a state where the relative speed is extremely large on the negative side is detected, the initial value of the target throttle opening is reduced or set to 0, and conversely, based on the following distance L and the relative speed ΔV, the own vehicle moves from the preceding vehicle. When a state where the vehicle is far away or a state where the relative speed is extremely large on the positive side is detected, the initial value of the target throttle opening is increased.
[0088]
In this way, by correcting the initial target throttle opening value, which is a parameter of the throttle initial control, appropriately according to the following distance L and the relative speed ΔV, unnecessary acceleration or two steps at the start of the preceding vehicle following control is performed. Therefore, the preceding vehicle following control can be started smoothly, and the driver's uncomfortable feeling can be eliminated.
[0089]
The effect will be specifically described with reference to FIGS.
FIG. 12 is a diagram for explaining the throttle initial control. FIG. 13 is a diagram showing a comparison between the effects of the present invention and the conventional example when the own vehicle is approaching the preceding vehicle or when there is an inter-vehicle distance but the relative speed is very large on the minus side. FIG. 14 is a diagram showing a comparison between the effects of the present invention and the conventional example when the host vehicle is far away from the preceding vehicle or when the relative speed is very large on the positive side.
[0090]
As shown in FIG. 12, in the throttle initial control, at the start of the vehicle speed control, the throttle valve is opened at the maximum opening speed of the actuator up to the throttle opening required to maintain the set speed ((A- At point A of the throttle opening shown in 1), the control after that operation is started smoothly ((A-2) in FIG. 12).
[0091]
However, when the own vehicle is approaching the preceding vehicle or when there is an inter-vehicle distance but the relative speed is extremely large on the minus side, the set switch is turned ON ((A-3) in FIG. 13) to control the following of the preceding vehicle. Immediately after the start, the throttle initial control is performed as it is, and if the throttle valve is once opened to the original throttle opening (point B in FIG. 13 (A-2)), the speed is reduced immediately after the preceding vehicle following control is started. Despite the necessity, unnecessary acceleration is exhibited (point C in FIG. 13 (A-1)).
[0092]
On the other hand, in the traveling speed control device to which the present invention is applied, in the same situation, even if the ON of the set switch is detected ((B-3) in FIG. 13), immediately after the start of the preceding vehicle following control, The throttle initial control is not performed, or the throttle initial control is performed, but the effect is suppressed ((B-2) in FIG. 13), so that the vehicle starts to decelerate immediately after the start of the preceding vehicle follow-up control ((B- 1)).
[0093]
Conversely, when the host vehicle is far from the preceding vehicle or when the relative speed is very large to the plus side, the set switch is turned ON ((A-3) in FIG. 14) immediately after the start of the preceding vehicle following control. When the throttle initial control is executed as it is and the throttle valve is once opened to the original throttle opening (point D in FIG. 14 (A-2)), the vehicle is accelerated again by the vehicle speed control ((A in FIG. 14). (Point E of -2)), (A-1) in FIG. 14 in which acceleration is performed in two stages.
[0094]
On the other hand, in the traveling speed control device to which the present invention is applied, even if ON of the set switch is detected in the same situation ((B-3) in FIG. 14), the situation (inter-vehicle distance or relative vehicle speed) The throttle initial control immediately after the start of the preceding vehicle following control is corrected ((B-2) in FIG. 14), so that the vehicle smoothly accelerates immediately after the start of the preceding vehicle following control (FIG. 14). (B-1)).
[0095]
Although the embodiments of the present invention have been specifically described above, it is needless to say that the present invention is not limited to the above embodiments.
That is, in the above-described embodiment, the correction of the throttle initial control is performed using the target throttle opening initial value T._voriHas been described as being corrected, but the present invention is not limited to this. For example, another control target value of the throttle initial control, for example, the target driving force initial value F_oriAnd target engine torque initial value T_eri, The throttle initial control may be corrected. With this, a similar effect can be obtained.
[0096]
Further, in the above-described embodiment, the case where the throttle initial control is corrected based on the information on both the inter-vehicle distance and the relative speed has been described. However, the throttle initial control is performed based on at least one of the information on the inter-vehicle distance or the relative speed. The control may be corrected.
Further, in the above-described embodiment, the correction for the throttle initial control is specifically described as the first correction method and the second correction method, but it is needless to say that the present invention is not limited to this specific example. Further, the case has been described in which the correction unit 47 and the increase / decrease rate map unit 48, which are means for realizing the correction, are provided in the vehicle speed control unit 40. You may comprise.
[0097]
Further, the setting of the throttle initial control is not limited to correcting and realizing the original control target value used in the throttle initial control. For example, a new control target value may be obtained by some arithmetic expression based on the inter-vehicle distance or the relative speed irrespective of the original control target value, and the throttle initial control may be performed based on this control target value.
Further, the various processing units may be realized as a circuit, or may be realized by a software form of a microcomputer.
[Brief description of the drawings]
FIG. 1 is a schematic vehicle configuration diagram illustrating an example of a traveling speed control device according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of the traveling speed control device.
FIG. 3 is a block diagram showing a configuration of a preceding vehicle following control unit of the traveling speed control device.
FIG. 4 is a block diagram showing a configuration of a target inter-vehicle distance calculation constant determining unit of the preceding vehicle following control unit.
FIG. 5 is a block diagram showing a configuration of a vehicle speed control unit of the traveling speed control device.
FIG. 6 is a characteristic diagram showing an engine non-linear steady-state characteristic map.
FIG. 7 is a block diagram showing a configuration of a throttle control unit of the traveling speed control device.
FIG. 8 is a characteristic diagram showing a map including a relationship between a pre-compensation drive signal (duty ratio) command value Duty_R (t) and a vacuum (VAC) / vent (VENT) drive signal Duty (t).
FIG. 9 is a diagram showing a configuration of a throttle actuator.
FIG. 10 is a diagram showing a map from which a throttle initialization amount increase / decrease rate can be obtained based on an inter-vehicle distance deviation ΔL and a relative speed ΔV.
FIG. 11 is a flowchart illustrating a processing procedure of the traveling speed control device.
FIG. 12 is a diagram used for describing throttle initial control.
FIG. 13 is a diagram used to explain the effect of the present invention when the own vehicle is approaching the preceding vehicle or the inter-vehicle distance is large but the relative speed is extremely large on the negative side.
FIG. 14 is a diagram used to explain the effect of the present invention when the host vehicle is far from the preceding vehicle or the relative speed is very large on the positive side.
[Explanation of symbols]
1 engine
2 automatic transmission
3 Inter-vehicle distance sensor
4 running speed sensor
5 running speed control unit
7 Throttle actuator
8 brake actuator
11 distance measurement signal processing unit
12 running speed signal processing unit
13 Brake control unit
14 gear ratio control unit
20 Traveling vehicle tracking control unit
40 vehicle speed control unit
45 ° throttle opening command value calculation unit
47 ° correction unit
48 change rate map
60 ° throttle control
70 ° throttle actuator

Claims (12)

In a traveling speed control device having a throttle initial control function for temporarily increasing the throttle opening at the start of vehicle speed control for controlling the traveling speed of the own vehicle so that the own vehicle follows the preceding vehicle,
Setting means for setting the throttle initial control based on at least one of an inter-vehicle distance between the preceding vehicle and the own vehicle or a relative speed that is a difference between the running speed of the preceding vehicle and the running speed of the own vehicle. A traveling speed control device characterized by the above-mentioned. The travel speed control device according to claim 1, wherein the setting unit corrects a control target value of the throttle initial control. The setting means does not execute the throttle initial control when the inter-vehicle distance is smaller than a reference distance or when it is detected that the own vehicle is approaching a preceding vehicle based on the relative speed. Item 2. The traveling speed control device according to Item 1. When the inter-vehicle distance is smaller than a reference distance or when it is detected that the own vehicle is approaching a preceding vehicle based on the relative speed, the setting means increases the throttle opening degree executed by the throttle initial control. The travel speed control device according to claim 1, wherein the amount is reduced. When the inter-vehicle distance is greater than a reference distance or when it is detected that the host vehicle is moving away from the preceding vehicle based on the relative speed, the setting means increases the throttle opening degree performed by the throttle initial control. The travel speed control device according to claim 1, wherein the amount is increased. The setting means obtains an increase / decrease rate corresponding to the inter-vehicle distance or the relative speed from a map prepared in advance, and multiplies the increase / decrease rate by a throttle opening implemented by the throttle initial control. The traveling speed control device according to any one of claims 1 to 5, wherein the setting is performed. In a traveling speed control method of performing a throttle initial control for temporarily increasing a throttle opening at a start of a vehicle speed control for controlling a traveling speed of the own vehicle and following the own vehicle with a preceding vehicle,
A travel speed, wherein the throttle initial control is set based on at least one of an inter-vehicle distance between the preceding vehicle and the own vehicle or a relative speed that is a difference between a travel speed of the preceding vehicle and a travel speed of the own vehicle. Control method. 8. The traveling speed control method according to claim 7, wherein the setting of the throttle initial control is performed by correcting a control target value of the throttle initial control. When the inter-vehicle distance is smaller than a reference distance or when it is detected that the own vehicle is approaching a preceding vehicle based on the relative speed, the throttle initial control is set by not performing the throttle initial control. The running speed control method according to claim 7, wherein: When the inter-vehicle distance is smaller than a reference distance or when it is detected that the own vehicle is approaching the preceding vehicle based on the relative speed, by suppressing the increase amount of the throttle opening executed by the throttle initial control. The running speed control method according to claim 7, wherein the setting of the throttle initial control is performed. When the inter-vehicle distance is larger than a reference distance or when it is detected that the own vehicle is moving away from the preceding vehicle based on the relative speed, by increasing the amount of increase in the throttle opening performed by the throttle initial control, The running speed control method according to claim 7, wherein the setting of the throttle initial control is performed. Setting the throttle initial control by obtaining an increase / decrease rate corresponding to the inter-vehicle distance or the relative speed from a map prepared in advance, and multiplying the increase / decrease rate by a throttle opening executed by the throttle initial control. The running speed control method according to any one of claims 7 to 11, wherein:

Images