JP3680701B2 - Vehicle speed control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle speed control device capable of accurately and rapidly determining constant speed travel control interruption due to temporary acceleration. SOLUTION: Throttle opening is estimated from a drive signal of a throttle actuator using a control model of the throttle actuator. The actual throttle opening taking account of the response characteristic (integrating characteristic and dead time) of the throttle actuator included in the control model can thereby be obtained, and constant speed travel control interruption (whether temporary acceleration or not) is determined on the basis of the obtained actual throttle opening. As a result, whether temporary acceleration or not can be determined with accuracy, and there is no possibility of a conventional delay in determining temporary acceleration by a driver.

Description

さらに、スロットルアクチュエータ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ため、補償前駆動信号Ｄｕｔｙ比指令値Ｄｕｔｙ＿Ｒ(ｔ）に対して図１５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）をスロットルアクチュエータ６０に出力する。
ここで補償前駆動信号Ｄｕｔｙ比指令値Ｄｕｔｙ＿Ｒ(ｔ）からＶＡＣ／ＶＥＮＴ駆動信号Ｄｕｔｙ(ｔ）を算出する非線形補償マップは、図１５に示すようにＤｕｔｙ＿Ｒ(ｔ）≧０の場合はＶＡＣモータ駆動信号を、Ｄｕｔｙ＿Ｒ(ｔ）＜０の場合はＶＥＮＴバルブ駆動信号を出力する。
【００６２】
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り、そのための負圧はバキュームモータを駆動して作ってもよいし、吸気管負圧を用いることも出来る。なお、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。
【００６３】
次に、図１のブレーキ圧指令値算出部６３０は、エンジン回転数Ｎ_Ｅ(ｔ）に基づいて、図１１に示すエンジン全性能マップからスロットル全閉時のエンジンブレーキトルクＴＥ_ＣＯＭ’を求め、エンジンブレーキトルクＴＥ_ＣＯＭ’とエンジントルク指令値ＴＥ_ＣＯＭ(ｔ）から次式によってブレーキ圧指令値ＲＥＦ_ＰＢＲＫ(ｔ）を算出し、ブレーキアクチュエータ５０へ出力する。
ＲＥＦ_ＰＢＲＫ(ｔ）＝(ＴＥ_ＣＯＭ−ＴＥ_ＣＯＭ’)・Ｇｍ・Ｇｆ／｛４・(２・ＡＢ・ＲＢ・μＢ)｝
ただし、Ｇｍは自動変速機の変速比、ＡＢはホイルシリンダ力（シリンダ圧×面積）、ＲＢはディクスロータ有効半径、μＢはパッド摩擦係数である。
【００６４】
次に、本発明の要点の一部である車速制御の中断処理について説明する。
図１の車速制御中断判定部６２０は、アクセルペダルセンサ９０で検出されたアクセル操作量ＡＰＯを入力し、アクセル操作量ＡＰＯと所定値とを比較する。
【００６５】
この所定値は、スロットルアクチュエータの制御モデルを用いてスロットルコントローラ５７５にて演算されたスロットル開度相当値ＴＶＯ(ｔ）であり、アクセル操作量ＡＰＯ（前記のようにスロットル開度に換算した値）が、スロットル開度相当値ＴＶＯ(ｔ）よりも大きくなった場合、つまり、運転者がアクセルペダルを踏んだことによりスロットルアクチュエータ６０によるスロットル開度以上にスロットルが開いた場合には、車速制御中断信号を出力する。
前記のように、スロットル開度相当値ＴＶＯ(ｔ）は駆動信号からスロットルアクチュエータの制御モデルを使って推定演算したスロットル開度であるから、制御モデルに含まれるスロットルアクチュエータの応答特性（積分特性や無駄時間）を考慮した現実のスロットル開度を得ることが出来る。そして、この値を用いて定速走行制御中断の判断（一時加速か否かの判断）を行うので、一時加速か否かを精度良く判定することが出来、かつ、従来の所定値以上の差を条件とした場合のように運転者による実際の一時加速の判定が遅れるおそれもない。
また、スロットルアクチュエータが負圧式アクチュエータである場合には、前記のように制御応答の遅れがより顕著（大きい）であるため、本発明の効果がより大きい。
【００６６】
以上の制御に続いて、車速制御中断信号により、駆動トルク指令値演算部５３０、目標スロットル開度算出部５７０は、それまでの演算を初期化する。
【００６７】
次に、図１３に戻って、無段変速機７０内の構成を説明する。無段変速機７０は、例えばいわゆるＣＶＴ（Continuously Variable Transmission）である。そして変速マップ７３は自車速Ｖ_Ａ(ｔ）、アクセル操作量ＡＰＯを入力としてエンジン回転数指令値Ｎ_{ＩＮ＿ＣＯＭ}を出力するものであり、車速コントローラ５００内の変速マップ５４４と同一特性のマップである。
【００６８】
回転数ＬＩＭＩＴ部７４は、変速マップ７３から出力されたエンジン回転数指令値Ｎ_{ＩＮ＿ＣＯＭ}に対して、上限回転数制限処理（例えば、Ｎ_{ＩＮ＿ＣＯＭ＿ＤＥＣ}≦６４００［ｒｐｍ］）を行い、エンジン回転数指令値Ｎ_{ＩＮ＿ＣＯＭＣＶＴ}を出力する。
【００６９】
変速比指令値演算部７５は、自車速Ｖ_Ａ(ｔ）とエンジン回転数指令値Ｎ_{ＩＮ＿ＣＯＭＣＶＴ}を入力して、下式によって変速指令値ＤＲＡＴＩＯ_ＣＶＴ(ｔ）を求める。
ＤＲＡＴＩＯ_ＣＶＴ(ｔ）
＝Ｎ_{ＩＮ＿ＣＯＭＣＶＴ}・２π・Ｒｔ／(６０・Ｖ_Ａ(ｔ）・Ｇｆ）
切替スイッチ７１は、定速走行時に車速制御コントローラ５００から送られてくる変速比指令値ＤＲＡＴＩＯ_ＬＰＦ(ｔ）と通常走行時に無段変速機７０内で演算される変速比指令値ＤＲＡＴＩＯ_ＣＶＴ(ｔ）とを切替えるものであり、この切替えは、図１のセットスイッチ２０が押された際に車速指令最大値設定部５２０でセットされる車速制御中フラグ（セットスイッチ２０が押されたとき通常走行から定速走行に切替る）に応じて行われる。
【００７０】
ローパスフィルタ部７２は、切替スイッチ７１で選択された変速比指令値と車速制御中フラグおよび車速制御中断判定部６２０から出力される車速制御中断中信号を入力して、以下に示すように、走行状態に応じてローパスフィルタの時定数を切替え、その結果の出力信号をサーボ部７６へ送って変速機を制御する。 なお、変速比指令値ＤＲＡＴＩＯ(ｔ）を入力とし、実変速比を出力とした場合の変速比制御の伝達特性は、下式のように、一次遅れ系の伝達特性Ｇｒ(ｓ）で表すことができる。
Ｇｒ(ｓ）＝１／(Ｔ_ＣＶＴ・ｓ＋１）
ただし、Ｔ_ＣＶＴは無段変速機７０の変速時の応答特性を決める時定数（所定範囲内の可変値）である。
上記のＴ_ＣＶＴが前記走行状態に応じて切替えられるローパスフィルタの時定数に相当する。
【００７１】
切替の内容は次のとおりである。
（１）定速走行中、すなわち、車速指令最大値設定部５２０で判定される車速制御中フラグが制御中側で、かつ、車速制御中断判定部６２０で判定される車速制御中断フラグが中断中止側の場合。
この場合には或る決まった一定の緩やかな応答特性としたいため、無段変速機制御時定数Ｔ_ＣＶＴを一定（例えばＴ_ＣＶＴ＝０.５ｓｅｃ）に設定する。
【００７２】
（２）運転者が自らの操作で加速するため、アクセルペダルを踏み込み、車速制御が中断された場合、すなわち、車速指令最大値設定部５２０で判定される車速制御中フラグが制御中側で、かつ、車速制御中断判定部６２０で判定される車速制御中断フラグが中断中止側から中断側へ切り替わった場合。
この場合は、加速のため無段変速機コントローラは一旦急激にダウンシフト変速を行う。これは一般に、キックダウン変速と呼ばれ、その際、無段変速機制御時定数Ｔ_ＣＶＴを０.５ｓｅｃよりも速い０.２ｓｅｃに設定する。
【００７３】
（３）運転者が車速指令値最大値Ｖ_ＳＭＡＸを越える自ら希望する車速まで加速し、車速制御中断状態のまま、その車速で巡航した後、運転者によりアクセルペダルが戻された場合、すなわち、車速指令最大値設定部５２０で判定される車速制御中フラグが制御中側で、かつ、車速制御中断判定部６２０で判定される車速制御中断フラグが中断側で、かつ、アクセルペダルが閉じる側に操作された場合。
この場合は、変速によるショックを防止するため、無段変速機コントローラは無段変速機制御時定数Ｔ_ＣＶＴは０.５ｓｅｃよりも遅い０.８ｓｅｃに設定する。
【００７４】
以上のように、無段変速機制御時定数Ｔ_ＣＶＴを走行状態に応じて切替えることにより、運転者の感覚にあった変速特性を提供することができる。また、変速機の動特性を決定する時定数Ｔ_ＣＶＴを切り替えることによって定速走行制御中断時と再開時における応答性を向上させ、変速機の変速ショックを軽減するように構成しているので、変速制御マップが定速走行用の１種だけで済むため、従来のように定速走行用と中断時用（通常走行用）との２種を切り替えて使用するのに比べて、メモリが少なくて済み、かつ、変速機用のマップと車速制御装置用のマップ５４４として同一特性のマップを使用できるので、設計が容易になる。
【００７５】
また、車速制御中断判定部６２０は、アクセル操作量ＡＰ０が所定値未満に戻ったときに車速制御中断信号の出力を停止し、かつ、自車速Ｖ_Ａ(ｔ）が車速指定最大値Ｖ_ＳＭＡＸよりも大きい場合には、減速要求を駆動トルク指令値算出部５３０に出力する。そして、駆動トルク指令値算出部５３０は、車速制御中断判定部６２０からの車速制御中断信号の出力が停止され、かつ減速要求を入力した場合には、演算した駆動力指令値ｄ_ＦＣ(ｔ）を、スロットルで実現するように、目標スロットル開度算出部５７０で算出されたスロットル開度で減速制御されるが、スロットル全閉だけでは制動力が足りない場合は、スロットルと変速比で実現するように、降坂路、平坦路の別に関わらず、変速比指令値算出部５４０から変速比指令値ＤＲＡＴＩＯ（シフトダウン要求）を出力して、無段変速機７０のシフトダウン制御を行い、制動力不足を補うように制御する。
【００７６】
また、駆動（この場合は制動）力指令値ｄ_ＦＣ(ｔ）が大きく、無段変速機のシフトダウンによる制動力でも上限にある場合には、平坦路では通常ブレーキにより制動力を補うが、降坂路では、駆動トルク指令値算出部５３０からブレーキ圧指令値算出部６３０へのブレーキ制御禁止信号Ｂ_Ｐを出力し、それによって降坂路でのブレーキ制御を禁止している。このように制御する理由は次のとおりである。すなわち、降坂路ではブレーキで減速を行うと連続してブレーキをかけることが必要になり、ブレーキフェード等の問題を生じるおそれがある。そのため、上記のように降坂路ではスロットル開度と無段変速機のシフトダウン制御による減速のみで必要な制動力を得るように制御することにより、ブレーキを用いずに制動するように構成している。
【００７７】
以上のような方法により、運転者が一時的にアクセルペダルを踏んで加速することによって定速走行制御が中断した後、再び定速走行制御に復帰した場合においても、変速機のシフトダウンによって、スロットル開度全閉制御のみの減速度よりも大きな減速度を得られるようになるため、目標車速への収束時間を短くすることができる。また、無段変速機を使うことによって、長い下り坂でも変速ショックが発生することなく、スロットル開度全閉制御のみの減速度よりも大きく、かつ、車速指令値変化量ΔＶ_ＣＯＭ(ｔ）に基づいた駆動トルクを実現するようにスロットルおよび変速比が制御されるため、所定の減速度を保ったまま、スムーズに減速できるようになる。なお、通常の有段変速機ではシフトダウン時にショックが生じるので、従来は上記のように減速制御要求が大きい場合でもスロットル制御のみを行い、変速機のシフトダウン制御はしていなかった。しかし、無段変速機を用いればスムーズにシフトダウン出来るので、上記のごとき制御を行うことにより、スロットル開度全閉制御のみの減速度以上の大きな減速度で円滑に減速することができる
次に、車速制御の中止処理について説明する。
図１の駆動輪加速度算出部６００は、自車速Ｖ_Ａ(ｔ）を入力し、下式によって駆動輪加速度α_ＯＢＳ(ｔ）を演算する。
α_ＯＢＳ(ｔ）＝〔Ｋ_ＯＢＳ・ｓ／（Ｔ_ＯＢＳ・ｓ^２＋ｓ＋Ｋ_ＯＢＳ）〕・Ｖ_Ａ(ｔ）
ただし、Ｋ_ＯＢＳは定数、Ｔ_ＯＢＳは時定数である。
なお、上記の自車速Ｖ_Ａ(ｔ）は、前記のようにタイヤ（駆動輪）の回転速度から算出した値であるから、この値自体が駆動輪の回転速度に対応した値であり、上記の駆動輪加速度α_ＯＢＳ(ｔ）は駆動輪速度Ｖ_Ａ(ｔ）から車速の変化量（駆動輪加速度）を求めた値になっている。
【００７８】
そして車速制御中止判定部６１０は、駆動輪加速度演算部６００で求めた駆動輪加速度α_ＯＢＳ(ｔ）と所定の加速度制限値α（この加速度は車速の変化量に対応する値であり、例えば０.２Ｇ）とを比較し、駆動輪加速度α_ＯＢＳ(ｔ）が加速度制限値αを超えた場合に、車速制御中止信号を出力する。この車速制御中止信号により、駆動トルク指令値算出部５３０および目標スロットル開度算出部５７０は、その演算を初期化する。なお、車速制御が一旦中止されると、セットスイッチ２０を再度オンにするまで、車速制御は復帰しない。
【００７９】
図１の装置は、車速指令値変化量決定部５９０で決定した車速指令値変化量ΔＶ_ＣＯＭ(ｔ）に基づいた車速指令値で車速を制御するシステムであるため、通常の状態では前記の車速指令値変化量制限値〔例えば０.０６Ｇ＝０.０２１（ｋｍ／ｈ）／１０（ｍｓ）〕を超える車速変化は生じない。したがって駆動輪加速度α_ＯＢＳ(ｔ）が上記の車速指令値変化量制限値に対応した値よりも大きい所定の加速度制限値α（例えば０.２Ｇ）を超えた場合というのは、駆動輪にスリップが発生した可能性が高い。このように駆動輪加速度α_ＯＢＳ(ｔ）と予め定めた所定の加速度制限値αを比較することにより、スリップ発生を検出することができる。そのため、ＴＣＳ(トラクションコントロールシステム）等のスリップ抑制装置等で加速度センサを別途設けたり、駆動輪と従動輪との回転数差を検出したりすることなく、通常の車速センサ（駆動輪の回転速度を検出するセンサ）からの出力で駆動輪加速度α_ＯＢＳを求めることにより、スリップ判断と、制御の中止判断を行うことができる。また、車速指令値変化量ΔＶ_ＣＯＭ(ｔ）を大きくすることで目標車速への応答性を向上させることができる。なお、駆動輪加速度α_ＯＢＳ(ｔ）と所定値との比較から定速走行制御中止を判断する代わりに、車速指令値変化量決定部５９０で演算している車速指令値変化量ΔＶ_ＣＯＭ(ｔ）と駆動輪加速度α_ＯＢＳ(ｔ）との差が所定値以上になった場合に制御を中止させるようにしても良い。
【００８０】
また、図１０の車速指令値決定部５１０において、自身で演算した車速指令値Ｖ_ＣＯＭ(ｔ）が、入力した自車速Ｖ_Ａ(ｔ）よりも高く、かつ、減速方向に変化した場合（Ｖ_ＳＭＡＸ＜Ｖ_Ａか否か）を判定する。そして、車速指令値Ｖ_ＣＯＭ(ｔ）を自車速Ｖ_Ａ(ｔ）もしくはそれ以下の所定の速度Ｖ_ＣＯＭ(ｔ）(例えば自車速から５ｋｍ／ｈを引いた値）に設定するとともに、図７に示した駆動トルク指令値算出部５３０における、Ｃ_２(ｓ）・Ｖ_Ａ(ｔ）−Ｃ_１(ｓ）・ｄ_ＦＣ(ｔ）＝ｄ_Ｖ(ｔ）の出力をゼロにするように、Ｃ_２(ｓ）とＣ_１(ｓ）の積分器の初期値を自車速Ｖ_Ａ(ｔ）とする。この結果Ｃ_１(ｓ）の出力もＣ_２(ｓ）の出力もＶ_Ａ(ｔ）となり、結果として外乱推定値ｄ_Ｖ(ｔ）は、ゼロとなる。
さらに、上述の制御を行うタイミングとして、Ｖ_ＣＯＭ(ｔ）の変化率であるΔＶ_ＣＯＭ(ｔ）が所定値(０.０６Ｇ）より減速側に大きかった場合とする。これにより、不要な初期化（Ｖ_Ａ(ｔ）→Ｖ_ＣＯＭ(ｔ）の初期化と積分器の初期化）が減少するので、減速ショックが少なくなる。
上記のように車速指令値（目標車速に到達するまでの時々刻々の制御指令値）が実車速よりも大きく、かつ、車速指令値の時間的変化が減速方向に変化した場合に、車速指令値を実車速もしくはそれ以下の所定の車速に変更することにより、迅速に目標車速に収束させることが出来る。また、前記の設定した実車速もしくはそれ以下の車速を用いて駆動トルク指令値算出部５３０を初期化することにより、制御の継続性を保つことができる。
【００８１】
なお、運転者が設定した先行車との目標車間距離を保って走行するように、実車間距離を目標車間距離に一致させるように制御する車速制御装置においては、上記車速指令値が上記目標車間距離を保つように設定されるが、この場合には、実車間距離が所定値以下で、かつ、車速指令値変化量ΔＶ_ＣＯＭ(ｔ）が減速側に所定値（０.０６Ｇ）より大きかった場合に、車速指令値Ｖ_ＣＯＭ(ｔ）の変更〔Ｖ_Ａ(ｔ）→Ｖ_ＣＯＭ(ｔ）〕と駆動トルク指令値算出部５３０（具体的にはその中の積分器）の初期化を行う。このように構成することにより、迅速に目標車間距離に収束させることが出来るので、先行車に近寄り過ぎるというおそれがなくなり、かつ、制御の継続性を保つことができる。また、これにより、不要な初期化〔Ｖ_Ａ(ｔ）→ΔＶ_ＣＯＭ(ｔ）の初期化と積分器の初期化）が減少するので、減速ショックが少なくなる。
【図面の簡単な説明】
【図１】本発明の車速制御装置の全体の構成を示すブロック図。
【図２】横Ｇ車速補正量算出部５８０の構成を示すブロック図。
【図３】自車速Ｖ_Ａとローパスフィルタのカットオフ周波数ｆｃと関係を示す特性図。
【図４】車速補正量Ｖ_ＳＵＢ(ｔ）を計算するための補正係数と横Ｇの値Ｙ_Ｇ(ｔ）との関係を示す特性図。
【図５】固有振動数ω_ｎＳＴＲと自車速Ｖ_Ａとの関係を示す特性図。
【図６】自車速Ｖ_Ａ(ｔ）と車速指令最大値Ｖ_ＳＭＡＸとの偏差の絶対値と、車速指令値変化量ΔＶ_ＣＯＭ(ｔ）との関係を示す特性図。
【図７】駆動トルク指令値演算部５３０の構成を示すブロック図。
【図８】エンジン非線形定常特性マップの一例を示す図。
【図９】スロットル開度推定マップの一例を示す図。
【図１０】ＣＶＴ変速マップの一例を示す図。
【図１１】エンジン全性能マップの一例を示す図。
【図１２】駆動トルク指令値演算部５３０の他の構成例を示すブロック図。
【図１３】変速比指令値算出部５４０と無段変速機７０の内容を示すブロック図。
【図１４】スロットルコントローラ５７５の内容を示すブロック図。
【図１５】バキューム(ＶＡＣ）／ベント(ＶＥＮＴ）駆動信号Ｄｕｔｙ(ｔ）を求める際に用いるマップ。
【符号の説明】
１０…車速センサ ２０…セットスイッチ
３０…コーストスイッチ ４０…アクセラレートスイッチ
５０…ブレーキアクチュエータ ６０…スロットルアクチュエータ
７０…無段変速機 ７１…切替スイッチ
７２…ローパスフィルタ部 ７３…変速マップ
７４…回転数ＬＩＭＩＴ部 ７５…変速比指令値演算部
７６…サーボ部 ８０…エンジン回転センサ
９０…アクセルペダルセンサ １００…操舵角センサ
５００…車速制御部 ５１０…車速指令値決定部
５２０…車速指令最大値設定部 ５３０…駆動トルク指令値算出部
５４０…変速比指令値算出部 ５４１…スロットル開度推定マップ
５４２…制動用エンジン回転数指令値算出マップ
５４３…切替スイッチ ５４４…変速マップ
５４５…回転数ＬＩＭＩＴ部 ５４６…回転数ＬＩＭＩＴ部
５４７…切替スイッチ ５４８…変速比指令値演算部
５４９…ローパスフィルタ部 ５５０…実変速比算出部
５６０…エンジントルク指令値算出部 ５７０…目標スロットル開度算出部
５７５…スロットルコントローラ ５８０…横Ｇ車速補正量算出部
５８１…操舵角信号ＬＰＦ部 ５８２…横Ｇ算出部
５８３…車速補正量算出マップ ５９０…車速指令値変化量決定部
６００…駆動輪加速度算出部 ６１０…車速制御中止判定部
６２０…車速制御中断判定部 ６３０…ブレーキ圧指令値算出部
Ｖ_Ａ(ｔ）…自車速 Ｖ_ＳＭＡＸ…車速指令最大値
θ(ｔ）…操舵角 Ｖ_ＳＵＢ(ｔ）…車速補正量
θ_ＬＰＦ(ｔ）…操舵角ＬＰＦ値 Ｖ_ＣＯＭ(ｔ）…車速指令値
ΔＶ_ＣＯＭ(ｔ）…車速指令値変化量 ｄ_ＦＣ(ｔ）…駆動トルク指令値
ｄ_Ｖ(ｔ）…外乱推定値
ｄ_Ｖ(ｔ)’…駆動トルク指令値補正量
ｄ_ＦＡ(ｔ）…実駆動トルク Ｃ_Ｆ(ｓ）…前置補償器
Ｃ_Ｒ(ｓ）…規範モデル演算部
ｄ_ＦＣ１(ｔ）…基準駆動トルク指令値
Ｃ_１(ｓ）、Ｃ_２(ｓ）、Ｃ_３(ｓ）…補償器
Ｃ_３(ｓ)’…フィードバック補償器
ｓ…微分演算子 ｆｃ…ＬＰＦのカットオフ周波数
Ｙ_Ｇ(ｔ）…横Ｇの値 ψ…ヨーレイト
ω_ｎＳＴＲ…操舵角に対する車両応答の固有振動数
α_ＯＢＳ(ｔ）…駆動輪加速度
ＴＶＯ_ＥＳＴＩ…スロットル開度推定値
ＴＶＯ_ＣＯＭ…目標スロットル開度 ＡＰＯ…アクセル操作量
Ｎ_{ＩＮ＿ＣＯＭ}…エンジン回転数指令値
ＤＲＡＴＩＯ(ｔ）…変速比指令値 Ｔ_ＣＶＴ…無段変速機制御時定数
ＴＥ_ＣＯＭ(ｔ）…エンジントルク指令値
ＴＥ_ＣＯＭ’…エンジンブレーキトルク
ＲＥＦ_ＰＢＲＫ(ｔ）…ブレーキ圧指令値 Ｂ_Ｐ…ブレーキ制御禁止信号[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle speed control device that controls the speed of a vehicle, for example, a device that performs control so as to automatically run at a constant speed at a set target vehicle speed.
[0002]
[Prior art]
Conventionally, in a constant speed traveling device, when the actual value corresponding to the actual throttle opening becomes larger than the command value for controlling the throttle opening at that time (the calculated value in the vehicle speed control system), the driver By depressing the accelerator pedal, it is determined that the vehicle is temporarily accelerated (temporarily accelerated) through a route other than the vehicle speed control system, and the constant speed traveling control is interrupted.
[0003]
[Problems to be solved by the invention]
However, the actual value of the throttle opening during constant speed traveling control is delayed from the command value. That is, the actuator is operated in accordance with the command value to change the throttle opening, and the result of the change becomes an actual value. Therefore, there is always a slight delay between the command value and the actual value. For this reason, when shifting from acceleration to deceleration during constant speed traveling control, for example, when controlling to decrease because the speed exceeds the set value during constant speed traveling control, the actual value is more than the command value. May temporarily increase, and in such a case, there is a problem that it is determined that the acceleration is temporarily accelerated and the constant speed traveling control may be interrupted.
In addition, in order to solve the above-described problems, if the determination of interruption of constant speed traveling control is set when the actual value of the throttle opening is larger than the command value of the throttle opening by a predetermined value or more, This causes a problem that the determination of the temporary acceleration is delayed.
[0004]
The present invention has been made to solve the problems of the prior art as described above, and provides a vehicle speed control device capable of accurately and promptly performing determination of constant speed traveling control interruption due to temporary acceleration. With the goal. Another object of the present invention is to provide a vehicle speed control device that can reflect the driver's acceleration intention at the time of interruption of constant speed traveling control with good responsiveness and can reduce the shift shock of the transmission during the interruption. It is to be.
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention is configured as described in the claims. That is, in claim 1, the throttle opening command value is calculated so as to eliminate the deviation between the actual vehicle speed and the target vehicle speed, the drive signal is calculated based on the throttle opening command value, and the throttle opening is adjusted. In a vehicle speed control apparatus that performs constant speed traveling control so as to travel at the target vehicle speed by driving the throttle actuator with the drive signal, the throttle actuator drive signal isConsidering responsivenessUsing the control model,Compensated for response delay in throttle actuatorCalculate the throttle opening equivalent value corresponding to the actual throttle opening, and the amount of accelerator pedal operationCorresponded toThrottle openingofWhen the value becomes larger than the value corresponding to the throttle opening, the constant speed traveling control is interrupted.
  According to a second aspect of the present invention, a negative pressure actuator is used as the throttle actuator.
[0006]
  According to a third aspect of the present invention, when the driving force for eliminating the deviation between the actual vehicle speed and the target vehicle speed is insufficient in the control based on the throttle opening command value, the first shift control map is set based on the predetermined first shift control map. Means for calculating one shift command;Response characteristics during shifting determined by a variable time constant within a specified rangeA transmission having a second shift control map having the same characteristics as the first shift control map,
  The transmission includes the first shift command and the first shift command during constant speed running control.responseWhen the constant speed traveling control is interrupted, the second shift command is calculated from the second shift control map based on the accelerator pedal depression amount, and theresponseDetermine characteristicsSaidSwitching the time constant, the second shift command and the time constant are switched.responseIt is configured to be controlled by characteristics.
[0007]
According to a fourth aspect of the present invention, in the third aspect, the switching of the time constant is performed so that the time constant is made smaller during the interruption than during the constant speed traveling control.
According to a fifth aspect of the present invention, the switching of the time constant is performed based on an input of an interruption time signal indicating an interruption time of constant speed traveling control and an accelerator pedal operation direction.
Further, according to the sixth aspect of the present invention, the accelerator pedal operation direction is a direction in which the accelerator pedal is depressed and the direction in which the accelerator pedal is depressed. The time constant is switched so that the time constant is increased and the time constant is increased when the accelerator is returned at the time of interruption.
[0010]
【The invention's effect】
In the present invention, since the throttle opening is estimated from the throttle actuator drive signal using the throttle actuator control model, the throttle actuator response characteristics (integration characteristics and dead time) included in the control model are actually considered. The throttle opening degree can be obtained, and constant speed running control interruption (temporary acceleration or not) is determined based on the throttle opening degree. Therefore, it is possible to accurately determine whether or not it is temporary acceleration, and there is no risk that the determination of actual temporary acceleration by the driver is delayed as in the case where the difference is equal to or more than the conventional predetermined value. Is obtained.
In addition, as described in claim 2, when the throttle actuator is a negative pressure type, the delay is most likely to occur, so the present invention is more effective.
[0011]
According to the third aspect of the present invention, the acceleration intention of the driver when the constant speed traveling control is interrupted can be reflected with good responsiveness by switching the time constant for determining the dynamic characteristics of the transmission, and the transmission control map is fixed. Since only one type for high-speed driving is required, compared to using two types of switching for constant speed driving and for interruption (normal driving) as in the past, less memory is required, and Since the maps having the same characteristics can be used in the transmission and the vehicle speed control device, the design is facilitated.
Further, according to claims 4 to 6, when the time constant for determining the dynamic characteristics of the transmission is switched, the acceleration intention of the driver at the time of interruption of the constant speed traveling control is reflected with good responsiveness and is interrupted. The shift shock of the transmission can be reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the overall configuration of the vehicle speed control device will be described.
FIG. 1 is a block diagram showing the overall configuration of the vehicle speed control apparatus of the present invention. The configuration and operation of each block in FIG. 1 will be described below.
First, when a system switch (not shown) is turned on, the entire apparatus is powered on and enters a standby state. In this state, when the set switch 20 is turned on, control is started.
The vehicle speed control unit 500 (portion surrounded by a broken line) is composed of a microcomputer and its peripheral components. The block inside the vehicle speed control unit 500 displays the calculation contents of the computer divided into blocks.
[0015]
In the vehicle speed control unit 500, the vehicle speed command value determination unit 510 has a vehicle speed command value V every control cycle 10ms._COM(t) is calculated. In addition, the code | symbol which attached | subjected (t) means that it is a value which changes with time. However, (t) may be omitted in the drawing.
[0016]
The vehicle speed command maximum value setting unit 520 displays the vehicle speed V when the set switch 20 is pressed._A(t) is the vehicle speed command maximum value V_SMAXSet as (target vehicle speed). In addition, own vehicle speed V_A(t) is the actual speed of the host vehicle detected by the vehicle speed sensor 10 from the number of rotations of the tire. In addition, the vehicle speed command maximum value V is set by the set switch 20 as described above._SMAXIs set, every time the coast switch 30 is pressed once, the vehicle speed command maximum value setting unit 520 displays the vehicle speed command maximum value V_SMAXIs set to a low value by 5 km / h. That is, when it is pressed n times, it is set to a value that is lower by n × 5 km / h [if the button is kept pressed, if the pressing time is t, for example, t (s) / 1 (s) × 5 (km / h)]. . In addition, the vehicle speed command maximum value V is set by the set switch 20 as described above._SMAXAfter the acceleration is set, the vehicle speed command maximum value setting unit 520 displays the vehicle speed command maximum value V each time the accelerator switch 40 is pressed once._SMAXIs set to a higher value by 5 km / h. That is, when it is pressed n times, it is set to a value higher by n × 5 km / h [if the key is kept pressed, if the time of pressing is t, for example, t (s) / 1 (s) × 5 (km / h)]. .
[0017]
Next, the lateral G vehicle speed correction amount calculation unit 580 determines the steering angle θ (t) of the steering wheel output from the steering angle sensor 100 and the own vehicle speed V._A(t) is input, and a vehicle speed correction amount V for correcting a vehicle speed command value, which will be described later, according to a lateral acceleration (hereinafter referred to as a lateral G)._SUB(t) is calculated. Specifically, as shown in FIG. 2, the lateral G vehicle speed correction amount calculation unit 580 includes a steering angle signal low-pass filter (hereinafter referred to as a steering angle signal LPF unit) 581, a lateral G calculation unit 582, and a vehicle speed correction amount. The calculation map 583 is used.
[0018]
First, the steering angle signal LPF 581 is calculated based on the vehicle speed V_A(t) and the steering angle θ (t) are input, and the steering angle LPF value θ_LPF(t) is calculated. θ_LPFIs represented by the following equation.
θ_LPF(t) = θ (t) / (TSTR · s + 1)
Where s is a differential operator (the same applies to the following formulas)
Here, the time constant TSTR of the LPF is TSTR = 1 / (2π · fc)
The cut-off frequency fc of the LPF is represented by the own vehicle speed V as shown in FIG._AIt is determined by a map of the cutoff frequency fc with respect to (t). In this map, the cut-off frequency fc is set lower as the vehicle speed increases. For example, 100 km / h takes a lower value than 50 km / h.
[0019]
The lateral G calculation unit 582 calculates the steering angle LPF value θ._LPF(t) and own vehicle speed V_A(t) is input, and the lateral Y value Y according to the following formula_G(t) is calculated.
Y_G(t) = {V_A(t)²・ Θ_LPF(t)} / {N · W · [1 + A · V_A(t)²]}
Where W is the wheel base of the vehicle, N is the steering gear ratio, and A is the stability factor.
[0020]
Although the above formula shows the case where the lateral G is detected from the steering angle, the following formula is used when the lateral G is detected by applying a low-pass filter to the yaw rate ψ (t) using the yaw rate sensor. That's fine.
Y_G(t) = V_A(t) ・ ψ_LPF
ψ_LPF= Ψ (t) / (T_YAW・ S + 1)
T_YAWIs the time constant of the low-pass filter._AThe larger the value (t), the larger the value.
[0021]
The vehicle speed correction amount calculation map 583 is a vehicle speed correction amount V for correcting the vehicle speed command value according to the lateral G._SUB(t) is calculated. Vehicle speed correction amount V_SUB(t) is calculated by multiplying a correction coefficient determined by the lateral G by a predetermined vehicle speed command value change amount limit value [for example, 0.021 (km / h) / 10 (ms) = 0.06 G]. Note that the value of the vehicle speed command value change amount limit value is the vehicle speed command value change amount ΔV shown in FIG._COMIt is equal to the maximum value of (t).
V_SUB(t) = correction coefficient × 0.021 (km / h) / 10 (ms)
As will be described later, a vehicle speed command value V that finally becomes a value for controlling the vehicle speed._COMWhen calculating (t), the vehicle speed correction amount V described above is used._SUB(t) is added as a subtraction term. Therefore, the vehicle speed correction amount V_SUBAs the value of (t) is larger, the vehicle speed command value V_COM(t) will be limited.
[0022]
The correction coefficient is the value Y of the lateral G as shown in FIG._GThe larger (t), the larger. This is because the vehicle speed command value V increases as the lateral G increases._COMThis is to provide a great restriction on the change in (t). However, as shown in FIG. 4, when the lateral G is 0.1 G or less, it is determined that there is no need to correct the vehicle speed command value, and the correction coefficient is set to zero. Further, when the lateral G is 0.3 G or more, it is a value that does not occur in normal use, and in order to prevent the correction amount from becoming excessive when the lateral G detection value increases accidentally, The correction coefficient is constant (for example, 2) for .3G or more.
[0023]
As will be described in detail later in the vehicle speed command value determination unit 510, when the target vehicle speed increases due to the operation of the acceleration switch 40, that is, when acceleration is requested, the current host vehicle speed V_A(t), vehicle speed command value change amount ΔV_COM(t) is added and the vehicle speed correction value V_SUBBy subtracting (t), the vehicle speed command value V_COM(t) is calculated. Therefore, the vehicle speed command value change amount ΔV_COM(t) is the vehicle speed correction value V_SUBIf it is larger than (t), it will accelerate, and if it is smaller, it will decelerate. As described above, the vehicle speed correction value V_SUBSince (t) is obtained by multiplying the vehicle speed command value change amount limit value (maximum value of the vehicle speed command value change amount) by a correction coefficient as shown in FIG. 4, for example, vehicle speed command value change amount limit value = vehicle speed. In the case of the command value change amount, when the correction coefficient is 1 (in the example of FIG._GWhen (t) = 0.2), the acceleration and deceleration are equal and the current vehicle speed is maintained. That is, in this example, the value Y of the lateral G_GWhen (t) is smaller than 0.2, the vehicle is accelerated, and when it is large, the vehicle is decelerated. Further, when the target vehicle speed is reduced by the operation of the coast switch 30, that is, when deceleration is requested, the current host vehicle speed V_AFrom (t), vehicle speed command value change amount ΔV_COM(t) and vehicle speed correction value V_SUBBy subtracting (t), the vehicle speed command value V_COM(t) is calculated. Therefore, in this case, the vehicle always decelerates, but the degree of deceleration depends on the vehicle speed correction value V_SUBThe larger (t), that is, the larger the lateral G, the larger. The above value 0.021 (km / h) / 10 (ms) for the vehicle speed command value variation limit value is a value assumed to be used on an expressway.
[0024]
As described above, the vehicle speed correction value V_SUB(t) is obtained by the product of the correction coefficient corresponding to the lateral G and the vehicle speed command value change limit value. When the lateral G increases, the value of the subtraction term (vehicle speed correction value) increases and the lateral G does not increase. The vehicle speed is controlled. However, as described in the steering angle signal LPF unit 581 in FIG. 2, the higher the vehicle speed region, the lower the cutoff frequency fc, so the time constant TSTR of the LPF increases and the steering angle LPF value θ_LPF(t) is reduced, and the lateral G estimated by the lateral G calculation unit 582 is also reduced. As a result, the vehicle speed correction value V obtained via the vehicle speed correction amount calculation map 583 is obtained._SUBSince (t) becomes small, it becomes difficult to apply correction to the vehicle speed command value by the steering angle (correction in the acceleration decreasing direction).
[0025]
To explain this point in detail, the natural frequency ω of the vehicle response to the steering angle_nSTRThe characteristic of is shown by the following formula.
ω_nSTR= (2W / V_A) √ [Kf · Kr · (1 + A · V_A ²) / M_V・ I]
However, Kf and Kr are front and rear tire cornering power (for one wheel), W is a wheelbase, m_VIs the vehicle mass, A is the stability factor, and I is the vehicle yaw moment of inertia.
Natural frequency ω_nSTRThe characteristic of the natural frequency ω is as the vehicle speed increases as shown in FIG._nSTRDecreases and the vehicle responsiveness to the steering angle deteriorates, but as the vehicle speed decreases, the natural frequency ω_nSTRIt becomes clear that the vehicle response to the steering angle is improved. That is, the lateral G is less likely to be generated even when steering is performed in the higher vehicle speed range, and the lateral G is more likely to be generated even if the steering is slightly performed in the lower vehicle speed range. Therefore, as shown in FIG. 3, the cut-off frequency fc is lowered in the higher vehicle speed region, so that the response is delayed and the vehicle speed command value due to the steering angle is less likely to be corrected.
[0026]
Next, the vehicle speed command value change amount determination unit 590 in FIG._A(t) and vehicle speed command maximum value V_SMAXBased on the absolute value of the deviation from the vehicle speed command value change amount ΔV according to the map shown in FIG._COM(t) is calculated. In this map, when the absolute value of the deviation is within a certain range (range B in FIG. 6), the vehicle speed command value changes as the absolute value increases so as not to exceed the acceleration limit value α described in the vehicle speed control stop determination unit 610. Amount ΔV_COMIncrease (t) to accelerate or decelerate as quickly as possible. And the smaller the absolute value of the deviation, the more the vehicle speed command value change ΔV is such that the acceleration feeling is not impaired._COM(t) is reduced and the vehicle speed command maximum value V_SMAXTry not to overshoot. In a range where the absolute value of the deviation is large (range A in FIG. 6), a value that does not exceed the acceleration limit value α is set to a constant value (for example, 0.06G). In addition, a small value (range C in FIG. 6) is a constant value (for example, 0.03 G).
[0027]
Further, the vehicle speed command value change amount determination unit 590 outputs the vehicle speed correction value V output from the lateral G vehicle speed correction amount calculation unit 580._SUB(t) is monitored and the vehicle speed correction value V_SUBIf the value of (t) once returns from zero to zero and then returns to zero, it is determined that traveling on the curved road has ended and the vehicle speed V_A(t) and vehicle speed command maximum value V_SMAXIt is detected whether is equal.
If it is determined that the curve has ended, the vehicle speed V described above is used._A(t) and vehicle speed command maximum value V_SMAXBased on the absolute value of the deviation from the vehicle speed command value variation ΔV using FIG._COMInstead of determining (t), the vehicle speed V when it is determined that the curve has ended._AFrom (t), vehicle speed command value change amount ΔV_COM(t) is determined. As the characteristic at that time, a characteristic showing the same tendency as in FIG. 6 is used. That is, the horizontal axis of FIG._A(t) -V_SMAXVehicle speed V instead of |_AUsing the map (not shown) changed to (t), the vehicle speed V_AAs (t) is smaller, the vehicle speed command value change amount ΔV_COM(t) has a characteristic set to be a small value. And this processing is the vehicle speed V_A(t) and vehicle speed command maximum value V_SMAXThe process ends when becomes equal.
[0028]
The actual vehicle speed V when it is determined that the curve has ended._AFrom (t), vehicle speed command value change amount ΔV_COMInstead of the above-described example for determining (t), the vehicle speed correction value V_SUBWhen (t) becomes a value other than zero, it is determined that traveling on a curved road has started, and the vehicle speed V at that time_A(start) is stored in advance, and the vehicle speed V when it is determined that the curved road has ended_ADifference from (end) ΔV_A= V_A(start) -V_A(end) (that is, the vehicle speed command value change amount ΔV from the magnitude of the vehicle speed command value correction)_COM(t) may be determined. As the characteristic at this time, a characteristic showing a tendency opposite to that in FIG. 6 is used. That is, the horizontal axis of FIG._A(t) -V_SMAXVehicle speed difference ΔV instead of |_AVehicle speed difference ΔV using a map (not shown) changed to_AIs larger, the vehicle speed command value change amount ΔV_COM(t) is set to take a small value. Note that this processing is based on the vehicle speed V_A(t) and vehicle speed command maximum value V_SMAXThe process ends when becomes equal.
[0029]
When traveling on a curved road, the vehicle speed command value is corrected so that the value of the lateral G does not become excessive, so the vehicle speed generally decreases. Therefore, as described above, after running on the curved road and the vehicle speed has dropped, the vehicle speed V at the end of the curved road_A(t) or vehicle speed difference ΔV at the start and end of a curve road (before and after the vehicle speed drops due to correction of the vehicle speed command value)_ADepending on the magnitude of the vehicle speed command value change amount ΔV_COM(t) is configured to be changed.
[0030]
Note that the vehicle speed is low at the end of the curve road or the vehicle speed difference ΔV_AWhen is large, it is estimated that the vehicle speed has dropped because the radius of curvature of the curved road is small (the curve is tight). If the curved road is continuous (for example, an S-shaped curve), there is a high possibility that the above situation will occur. Therefore, the vehicle speed at the end of the curve road is low or the vehicle speed difference ΔV_AIs larger, the vehicle speed command value change amount ΔV_COM(t) is reduced to reduce the acceleration of the vehicle speed control by the vehicle speed command value. Thereby, in a continuous curve (S-shaped road), a large acceleration is not performed every time the curve is turned. Similarly, the vehicle speed is high at the end of the curved road or the vehicle speed difference ΔV_AIs small, it is determined that the curve is a single curve, and the vehicle speed command value change amount ΔV_COMIncrease (t). As a result, the vehicle is accelerated immediately after the end of a single curve, so there is no risk that the acceleration will slow down and give the driver a sense of discomfort.
[0031]
Next, the vehicle speed command value determination unit 510 in FIG._A(t), vehicle speed correction value V_SUB(t), vehicle speed command value change amount ΔV_COM(t) and vehicle speed command maximum value V_SMAXAnd input the vehicle speed command value V as follows:_COM(t) is calculated.
(1) Vehicle speed command maximum value V_SMAXIs own vehicle speed V_AWhen larger than (t), that is, when an acceleration request is made by operating the acceleration switch 40 (or resume switch).
V_COM(t) = min [V_SMAX, V_A(t) + ΔV_COM(t) -V_SUB(t)]
That is, vehicle speed command maximum value V_SMAXAnd V_A(t) + ΔV_COM(t) -V_SUBSelect the smaller of (t) and the vehicle speed command value V_COM(t).
(2) V_SMAXAnd V_AWhen (t) is equal, that is, when a constant vehicle speed is maintained
V_COM(t) = V_SMAX-V_SUB(t)
That is, vehicle speed command maximum value V_SMAXTo vehicle speed correction value V_SUBBy subtracting (t), the vehicle speed command value V_COM(t).
(3) Maximum vehicle speed command value V_SMAXIs own vehicle speed V_AWhen smaller than (t), that is, when there is a deceleration request by operating the coast switch 30
V_COM(t) = max [V_SMAX, V_A(t) -ΔV_COM(t) -V_SUB(t)]
That is, vehicle speed command maximum value V_SMAXAnd V_A(t) -ΔV_COM(t) -V_SUBSelect the larger of (t) and vehicle speed command value V_COM(t).
Vehicle speed command value V as described above_COM(t) is determined, and the vehicle speed is controlled accordingly.
[0032]
Next, the drive torque command value calculation unit 530 reads the vehicle speed command value V_COM(t) and own vehicle speed V_A(t) is input, and a drive torque command value d as shown below_FC(t) is calculated. FIG. 7 is a block diagram illustrating an example of the configuration of the drive torque command value calculation unit 530.
First, the vehicle speed command value V_COM(t) as input, own vehicle speed V_ATransfer characteristic G when (t) is output_V(s) can be expressed by the following formula.
G_V(s) = 1 / (T_V・ S + 1) ・ e^{(-Lv · s)}
T_VIs the first-order lag time constant, L_VIs a dead time due to a delay in the powertrain system.
[0033]
Further, the vehicle model to be controlled is determined by the drive torque command value d_FCUsing (t) as the manipulated variable,_ABy modeling (t) as a controlled variable, the behavior of the power train of the vehicle can be expressed by a simple linear model expressed by the following equation.
V_A(t) = 1 / (m_V・ Rt ・ s) e^{(-Lv · s)}・ D_FC(t)
Where Rt is the effective turning radius of the tire, m_VIs the vehicle mass.
Thus, the drive torque command value d_FC(t) as input, own vehicle speed V_AThe vehicle model that outputs (t) has the form of 1 / s and thus has an integral characteristic.
[0034]
It should be noted that the characteristics of the control target include dead time L due to the delay of the powertrain system._VIn addition, the dead time L depends on the actuator and engine used._VBy using a disturbance estimator using an approximate zeroing method as described later, the nonlinear characteristic that changes the value of the drive torque command value d_FC(t) as input, own vehicle speed V_AThe vehicle model whose output is (t) can be expressed by the same equation as above.
[0035]
Here, the vehicle speed command value V_COM(t) as input, own vehicle speed V_AThe response characteristic of the control object when (t) is output is the predetermined first order delay T_VAnd dead time L_VTransfer characteristic G with elements_VWhen matched with the characteristic of (s), C as shown in FIG.₁(s), C₂(s) and C₃Using (s), it can be determined as follows. However, C₁(s), C₂(s) shows a disturbance estimator using an approximate zeroing method, which is a compensator that works to suppress the influence of disturbances and modeling errors.₃(s) shows a compensator using a model matching method.
Compensator C₁(s) = e^{(-Lv · s)}/ (T_H・ S + 1)
Compensator C₂(s) = (m_V・ Rt ・ s) / (T_H・ S + 1)
At this time, the estimated disturbance value d_V(t)
d_V(t) = C₂(s) ・ V_A(t) -C₁(s) ・ d_FC(t)
It becomes.
[0036]
In addition, ignoring the dead time of the controlled object,_V(s) is the time constant T_VIf the first-order low-pass filter of the compensator C₃(s) is a constant as follows.
Compensator C₃(s) = m_V・ Rt / T_V
C above₁(s), C₂(s), C₃The drive torque command value d is obtained by the compensator (s)._FC(t) is calculated by the following equation.
d_FC(t) = C₃(s) ・ {V_COM(t) -V_A(t)}-{C₂(s) ・ V_A(t) -C₁(s) ・ d_FC(t)}
The above drive torque command value d_FCThe drive torque is controlled based on (t). That is, using the engine non-linear steady state characteristic map measured in advance as shown in FIG._FC(t) shows actual driving torque d_FAA throttle opening command value that matches (t) is calculated, and if the negative driving torque of the engine is insufficient, it is distributed so as to be compensated by a transmission or a brake. In this way, the engine nonlinear steady-state characteristic can be linearized by controlling the throttle opening, the transmission, and the brake.
[0037]
When the continuously variable transmission 70 has a fluid converter with a lockup, a lockup state signal LU is sent from the controller of the continuously variable transmission 70._SIs input, and when it is determined that the lock-up state is established, the time constant T_H(C in FIG. 7₁(s), C₂(Described in the denominator of (s)). As a result, the vehicle speed control feedback correction amount (the feedback loop correction coefficient for maintaining a desired response characteristic) is reduced and can be adjusted to the response characteristic of the controlled object that is delayed when unlocked compared to when locked up. The stability of the vehicle speed control system is ensured both when the vehicle is up and unlocked.
[0038]
Further, in the drive torque command value calculation unit 530 shown in FIG. 7, a compensator C for compensating the transfer characteristic of the controlled object.₁(s) and compensator C₂Compensator C for achieving the response characteristic defined by (s) and the designer₃(s), but as shown in FIG. 12, a precompensator C for compensating for an arbitrary response characteristic determined by the designer._F(s), normative model calculation unit C for calculating an arbitrary response characteristic determined by the designer_R(s) and reference model calculation unit C_RFeedback compensator C for compensating for the deviation (target vehicle speed−own vehicle speed) from the response characteristic of (s).₃(s) 'can also be used.
[0039]
Precompensator C_F(s) is the vehicle speed command value V_COMActual vehicle speed V for (t)_ATransfer function G of (t)_VIn order to achieve (s), a reference drive torque command value d using a filter represented by the following equation:_FC1(t) is calculated.
d_FC1(t) = m_V・ Rt ・ s ・ V_COM(t) / (T_V・ S + 1)
Reference model calculation unit C_R(S) is the target response V of the vehicle speed control system._T(t) is the transfer function G_V(s) and vehicle speed command value V_COMCalculate from (t). Ie
V_T(t) = G_V(s) ・ V_COM(t)
It is.
[0040]
Feedback compensator C₃(s) ′ is the target response V_T(t) and actual vehicle speed V_AWhen a deviation occurs in (t), the drive torque command value correction amount d is set so as to eliminate this deviation._V(t) 'is calculated. D_V(t) 'is represented by the following equation.
d_V(t) ’= [(K_P・ S + K_I) / S] [V_T(t) -V_A(t)]
However, K_PIs the feedback compensator C₃(S) 'proportional control gain, K_IIs the feedback compensator C₃(S) 'is an integral control gain. Driving torque command value correction amount d_V(t) 'is the disturbance estimated value d described in FIG._VThis corresponds to (t).
At this time, the lockup state signal LU_SIf it is determined that the unlock-up state is present, the correction amount d_V(t) 'is calculated. That is,
d_V(t) ’= [(K_P′ ・ S + K_I′) / S] [V_T(t) -V_A(t)]
It is. However,
K_P‘<K_P
K_I‘<K_I
Therefore, the feedback gain becomes small. Therefore, the drive torque command value d_FC(t) is the reference drive torque command value d_FC1(t) and drive torque command value correction amount d_V(t) ’
d_FC(t) = d_FC1(t) + d_V(t) ’
Is calculated. In this way, the feedback gain is reduced during unlock-up compared to lock-up, so the change rate of the drive torque command value correction amount is reduced, resulting in a response characteristic of the controlled object that is delayed during unlock-up compared to lock-up. Therefore, the stability of the vehicle speed control system can be ensured both when locked up and when unlocked.
[0041]
Next, an actuator drive system that is a part of the main points of the present invention will be described.
The transmission ratio command value calculation unit 540 is configured to generate a drive torque command value d._FC(t), own vehicle speed V_A(t), the vehicle speed control interruption signal, the output of the coast switch 30 and the output of the accelerator pedal sensor 90 are input, the gear ratio command value DRATIO (t) is calculated as follows, and output to the continuously variable transmission 70 To do.
Here, the detailed operation of the gear ratio command value calculation unit 540 will be described using FIG. 13 separately for the coast switch-off state and the coast switch-on state. FIG. 13 is a block diagram showing the detailed contents of the gear ratio command value calculation unit 540 and the continuously variable transmission 70 in FIG. 1, and parts other than the gear ratio command value calculation unit 540 and the continuously variable transmission 70 are necessary. Only blocks are shown.
[0042]
(1) When coast switch 30 is off
(1-1) Driving engine speed command value calculation
Own vehicle speed V_A(t) and drive torque command value d_FC(t) is used as an input, and the throttle opening estimated value TVO is temporarily calculated from the driving throttle opening estimation map 541 as shown in FIG._ESTIIs calculated. Next, the changeover switch 543 estimates the throttle opening estimated value TVO calculated above._ESTIAnd the accelerator pedal sensor 90 output APO (the value converted into the throttle opening), and while the vehicle speed control interruption signal output from the vehicle speed control interruption determination unit 620 is being interrupted, the output of the accelerator pedal sensor 90 is output. While APO is not outputting the vehicle speed control interruption signal (interruption is interrupted), the estimated throttle opening TVO_ESTIIs output as the throttle opening.
[0043]
Further, the throttle opening and the vehicle speed V output via the changeover switch 543_A(t) is input, and the engine speed command value N obtained from the shift map 544 as shown in FIG._{IN_COM_ACC}In response to the upper limit rotational speed limiting process (for example, N_{IN_COM_ACC}≦ 6400 [rpm]), and drive engine speed command value N_{IN_COM_ACC}Is calculated and output to the changeover switch 547.
[0044]
(1-2) Calculation of braking engine speed command value
Own vehicle speed V_A(t) and drive torque command value d_FCThe engine speed command value N obtained from the braking engine speed command value calculation map 542, which is created based on the engine characteristics when the throttle is fully closed, using (t) as an input and different from the driving (541)._{IN_COM_DEC}In addition, an upper limit rotational speed limiting process (for example, N_{IN_COM_DEC}≦ 5000 [rpm]), the engine speed command value N for braking_{IN_COM_DEC}Is calculated and output to the changeover switch 547.
[0045]
(1-3) Gear ratio command value calculation
In the changeover switch 547, the drive torque command value d_FCWhen the sign of (t) is positive, the driving engine speed command value N_{IN_COM_ACC}Is negative, the braking engine speed command value N_{IN_COM_DEC}And select the final engine speed command value N_{IN_COM}And Then, in the gear ratio command value calculation unit 548, the host vehicle speed V_A(t) and final engine speed command value N_{IN_COM}Is input, and the shift command value DRATIO (t) is obtained from the following equation.
DRATIO (t) = N_{IN_COM}・ 2π ・ Rt / [60 ・ V_A(t) ・ Gf]
However, Gf is a final gear ratio.
[0046]
(1-4) Drive torque command value d_FC(t) When braking drive is switched
The low-pass filter unit 549 generates a drive torque command value d_FC(t) is input, and the drive torque command value d_FCIn order to prevent a sudden torque fluctuation, that is, a sudden change in the gear ratio when the gear shift control is executed, both when the sign of (t) is switched from positive to negative and when switched from negative to positive, the gear ratio command value DRATIO (t ) Is subjected to the low pass filter processing shown in the following equation.
[0047]
DRATIO_LPF(t) = DRATIO (t) / (T_nc・ S + 1)
T_ncIs the time constant of the low-pass filter (0 to 0.35 sec: T_ncVariable).
[0048]
here,
(A) Drive torque command value d_FCWhen (t) switches from positive (driving) to negative (braking)
Time constant T_ncSwitching (0 → 0.35 sec) is performed faster than when switching from braking to driving (B) below. That is, the time constant T is set to 530 ms so that the effect of the low-pass filter starts to be effective as soon as possible._ncFrom 0 sec (zero: no low-pass filter activated) to 0.35 sec.
[0049]
(B) Drive torque command value d_FCWhen (t) is switched from negative (braking) to positive (driving)
Time constant T_ncIs slowly switched (0.35 → 0 sec). In other words, in order to keep the effect of the low-pass filter as long as possible, the time constant T is taken over 800 ms._ncFrom 0.35 sec to 0 sec (zero: a state in which the low-pass filter is not activated).
[0050]
Thus, the drive torque command value d_FCAt the time of switching between positive and negative signs of (t), the time constant T of the low-pass filter_ncHas changed. Thus, in positive (driving), the low-pass filter time constant is set to 0 so that the low-pass filter is not effective, and in negative (braking), the low-pass filter time constant is set to 0.35 and the low-pass filter is enabled. If it is positive (drive), the torque control by the transmission is performed after the torque control by the throttle opening reaches the limit, so even if the drive torque command value changes greatly, the throttle control side Since the drive torque is shared with the transmission side, the drive torque at the transmission does not increase, but in negative (braking), the throttle is fully closed, so the drive torque command value If there is a large change, the transmission torque must be shared on the transmission side, and in order to prevent an increase in shift shock, a negative (braking) I try to make the filter work. Therefore, drive torque command value d_FCWhen (t) switches from positive (driving) to negative (braking), downshifting is performed, but the response speed of the continuously variable transmission 70 during constant speed traveling (a time constant T described later)._CVT= 0.5 sec), since the response speed is too fast, the engine speed may increase rapidly. However, the effect of the low-pass filter starts to take effect early, that is, with respect to the gear ratio command value DRATIO (t). By slowing down the response speed, it is possible to prevent the generation of noise due to a sudden increase in engine speed.
[0051]
Further, the drive torque command value d_FCWhen (t) switches from negative (braking) to positive (driving), a shift-up is performed, but even if the gear ratio command value DRATIO (t) changes abruptly, the effect of the low-pass filter is long effective. Therefore, the gear ratio command value DRATIO_LPFSince the change in (t) can be made smooth, the occurrence of a shift shock can be prevented.
[0052]
(2) When the coast switch 30 is on
The vehicle speed command maximum value V when the coast switch 30 is turned on._SMAXIs reduced, the previous gear ratio command value DRATIO (t-1) is held as the gear ratio command value DRATIO (t). For this reason, even when the coast switch 30 is continuously turned on, the gear ratio command value maintains the previous value, that is, the value immediately before the coast switch 30 is turned on, until the coast switch 30 is turned off. Therefore, when the set vehicle speed is returned by the acceleration switch 40 after greatly reducing the set vehicle speed, the engine speed is rapidly increased in the state where the throttle opening is controlled to open but the gear is not downshifted. Therefore, it is possible to prevent the generation of noise given to the driver.
[0053]
The actual gear ratio calculation unit 550 in FIG. 1 is configured to detect the engine speed N detected by the engine speed sensor 80 from the engine ignition signal._E(t) and own vehicle speed V_AFrom (t), the actual gear ratio RATIO (t) is calculated according to the following equation.
RATIO (t) = N_E(t) / [V_A(t) · Gf · 2π · Rt]
The engine torque command value calculation unit 560 of FIG._FCFrom (t) and RATIO (t), the engine torque command value TE_COM(t) is calculated.
TE_COM(t) = d_FC(t) / [Gf.RATIO (t)].
[0054]
The target throttle opening degree calculation unit 570 in FIG._COM(t) and engine speed N_EBased on (t), the target throttle opening TVO is calculated from the engine performance map as shown in FIG._COMIs output to the throttle controller 575.
[0055]
The throttle controller 575 has a target throttle opening TVO._COM(t) is input, and the drive signal command value Duty (t) is output to the throttle actuator 60 and the throttle opening equivalent value TVO (t) is output to the vehicle speed control interruption determination unit 620 as shown below. The throttle opening equivalent value TVO (t) is a value corresponding to the actual throttle opening, and is an estimated value calculated using a model as will be described later.
[0056]
Hereinafter, the throttle controller 575 will be described with reference to the block diagram of the throttle controller 575 shown in FIG.
The control model of the throttle actuator to be controlled is modeled by modeling the pre-compensation drive signal (Duty ratio) command value Duty_R (t) as an operation amount and the throttle opening equivalent value TVO (t) as a control amount. Can be represented by a simple linear model shown in FIG.
TVO (t) = (ka / s) · e^{-La · s}・ Duty_R (t)
However, ka: integral gain (opening / closing speed at Duty 100%), La: dead time.
As described above, the control model having the pre-compensation drive signal (Duty ratio) command value Duty_R (t) as an input and the throttle opening equivalent value TVO (t) as an output has an integral characteristic because it takes the form of 1 / s. I understand that.
[0057]
The characteristic to be controlled has a non-linear characteristic in which the dead time La varies depending on the actuator to be used. However, by using a disturbance estimator by an approximate zeroing method described later, a pre-compensation drive signal (Duty ratio) command value Duty_R ( A control model having t) as an input and a throttle opening equivalent value TVO (t) as an output can be expressed by the same equation as the above equation.
[0058]
Here, the response characteristic of the controlled object when the pre-compensation drive signal (Duty ratio) command value Duty_R (t) is input and the throttle opening equivalent value TVO (t) is output is the predetermined first order delay Ta. When matched with the characteristic of the transfer characteristic Ga (s) having the element of dead time La, C as shown in FIG.₄(s), C₅(s) and C₆Using (s), it can be determined as follows. However, C₄(s), C₅(s) shows a disturbance estimator using an approximate zeroing method, which is a compensator that works to suppress the influence of disturbances and modeling errors.₆(s) shows a compensator using a model matching method.
[0059]
Compensator C₄(s) = e^{-La · s}/ (Ta · s + 1)
Compensator C₅(s) = s / {ka · (Ta · s + 1)}
At this time, the estimated disturbance value d_va(t)
d_va(t) = C₅(s) ・ TVO (t) -C₄(s) ・ Duty_R (t)
It becomes.
[0060]
Further, if the dead time of the controlled object is ignored and the reference model is a first-order low-pass filter with a time constant Tb, the compensator C₆(s) is a constant as shown below.
[0061]
Compensator C₆(s) = 1 / (ka · Tb)
C above₄(s), C₅(s), C₆The precompensation drive signal (Duty ratio) command value Duty_R (t) is calculated by the following equation by the compensator (s).

Further, when a negative pressure type actuator is used as the throttle actuator, it is easily affected by non-linear factors such as friction at the time of ON / OFF of the vacuum motor for generating negative pressure and opening / closing of the vent valve, so that the pre-compensation drive signal duty ratio command value Duty_R A vacuum (VAC) / vent (VENT) drive signal Duty (t) subjected to nonlinear compensation using a map as shown in FIG. 15 with respect to (t) is output to the throttle actuator 60.
Here, the non-linear compensation map for calculating the VAC / VENT drive signal Duty (t) from the pre-compensation drive signal Duty ratio command value Duty_R (t) is VAC motor drive when Duty_R (t) ≧ 0 as shown in FIG. If the signal is Duty_R (t) <0, a VENT valve drive signal is output.
[0062]
Note that the negative pressure type actuator operates using negative pressure as a power source, and the negative pressure for that purpose may be generated by driving a vacuum motor, or intake pipe negative pressure may be used. Note that the negative pressure actuator is driven to open the throttle when vacuuming (VAC) and to close the throttle when venting (VENT).
[0063]
Next, the brake pressure command value calculation unit 630 in FIG._EBased on (t), the engine brake torque TE when the throttle is fully closed is determined from the engine total performance map shown in FIG._COM′ For the engine brake torque TE_COM'And engine torque command value TE_COMFrom (t), the brake pressure command value REF_PBRK(t) is calculated and output to the brake actuator 50.
REF_PBRK(t) = (TE_COM-TE_COM′) · Gm · Gf / {4 · (2 · AB · RB · μB)}
Where Gm is the gear ratio of the automatic transmission, AB is the wheel cylinder force (cylinder pressure × area), RB is the effective radius of the disk rotor, and μB is the pad friction coefficient.
[0064]
Next, the vehicle speed control interruption process, which is a part of the main points of the present invention, will be described.
The vehicle speed control interruption determination unit 620 in FIG. 1 inputs the accelerator operation amount APO detected by the accelerator pedal sensor 90, and compares the accelerator operation amount APO with a predetermined value.
[0065]
This predetermined value is the throttle opening equivalent value TVO (t) calculated by the throttle controller 575 using the throttle actuator control model, and the accelerator operation amount APO (the value converted into the throttle opening as described above). However, when the throttle opening equivalent value TVO (t) becomes larger, that is, when the throttle is opened more than the throttle opening by the throttle actuator 60 when the driver steps on the accelerator pedal, the vehicle speed control is interrupted. Output a signal.
As described above, the throttle opening equivalent value TVO (t) is the throttle opening estimated from the drive signal using the throttle actuator control model, and therefore the response characteristics (integration characteristics and It is possible to obtain the actual throttle opening considering the dead time). Since this value is used to determine whether the constant speed running control is interrupted (determining whether or not it is temporary acceleration), it is possible to accurately determine whether or not it is temporary acceleration, and a difference that is equal to or greater than the conventional predetermined value. There is no possibility that the determination of the actual temporary acceleration by the driver is delayed as in the case where the above condition is satisfied.
Further, when the throttle actuator is a negative pressure actuator, the delay of the control response is more noticeable (large) as described above, so the effect of the present invention is greater.
[0066]
Following the above control, the drive torque command value calculation unit 530 and the target throttle opening calculation unit 570 initialize the calculation so far by the vehicle speed control interruption signal.
[0067]
Next, returning to FIG. 13, the configuration in the continuously variable transmission 70 will be described. The continuously variable transmission 70 is, for example, a so-called CVT (Continuously Variable Transmission). The shift map 73 shows the vehicle speed V_A(t) Engine speed command value N with accelerator operation amount APO as input_{IN_COM}Is a map having the same characteristics as the shift map 544 in the vehicle speed controller 500.
[0068]
The engine speed limit unit 74 outputs an engine speed command value N output from the shift map 73._{IN_COM}To the upper limit rotational speed limiting process (for example, N_{IN_COM_DEC}≦ 6400 [rpm]), engine speed command value N_{IN_COMCVT}Is output.
[0069]
The gear ratio command value calculation unit 75 determines the vehicle speed V_A(t) and engine speed command value N_{IN_COMCVT}And input the shift command value DRATIO by the following formula_CVT(t) is obtained.
DRATIO_CVT(t)
= N_{IN_COMCVT}・ 2π ・ Rt / (60 ・ V_A(t) ・ Gf)
The changeover switch 71 is a gear ratio command value DRATIO sent from the vehicle speed controller 500 during constant speed running._LPF(t) and a gear ratio command value DRATIO calculated in the continuously variable transmission 70 during normal travel_CVT(t) is switched. This switching is performed when the vehicle speed control flag (set switch 20 is pressed) set by the vehicle speed command maximum value setting unit 520 when the set switch 20 of FIG. 1 is pressed. Switching from normal travel to constant speed travel).
[0070]
The low-pass filter unit 72 inputs the speed ratio command value selected by the changeover switch 71, the vehicle speed control in-progress flag, and the vehicle speed control interruption signal output from the vehicle speed control interruption determination unit 620, and travels as shown below. The time constant of the low-pass filter is switched according to the state, and the resulting output signal is sent to the servo unit 76 to control the transmission. Note that the transmission characteristic of the transmission ratio control when the transmission ratio command value DRATIO (t) is input and the actual transmission ratio is output is expressed by the first-order delay system transmission characteristic Gr (s) as shown in the following equation. Can do.
Gr (s) = 1 / (T_CVT・ S + 1)
T_CVTIs a time constant (variable value within a predetermined range) that determines the response characteristics of the continuously variable transmission 70 during shifting.
T above_CVTCorresponds to the time constant of the low-pass filter that is switched according to the running state.
[0071]
The contents of switching are as follows.
(1) During constant speed traveling, that is, the vehicle speed control flag determined by the vehicle speed command maximum value setting unit 520 is on the control side, and the vehicle speed control interrupt flag determined by the vehicle speed control interrupt determination unit 620 is interrupted. If on the side.
In this case, in order to obtain a certain constant and gentle response characteristic, the continuously variable transmission control time constant T_CVTIs constant (for example, T_CVT= 0.5 sec).
[0072]
(2) When the driver depresses the accelerator pedal to accelerate by his / her own operation and vehicle speed control is interrupted, that is, the vehicle speed control flag determined by the vehicle speed command maximum value setting unit 520 is on the control side. And the vehicle speed control interruption flag determined by the vehicle speed control interruption determination unit 620 is switched from the interruption interruption side to the interruption side.
In this case, the continuously variable transmission controller temporarily performs a downshift in order to accelerate. This is generally called a kickdown shift, and at that time, the continuously variable transmission control time constant T_CVTIs set to 0.2 sec, which is faster than 0.5 sec.
[0073]
(3) The driver sets the maximum vehicle speed command value V_SMAXIf the accelerator pedal is returned by the driver after cruising at the vehicle speed while suspending the vehicle speed control in an interrupted state, that is, the vehicle speed control determined by the vehicle speed command maximum value setting unit 520 When the middle flag is operated, the vehicle speed control interruption flag determined by the vehicle speed control interruption determination unit 620 is operated on the interruption side, and the accelerator pedal is closed.
In this case, in order to prevent a shock caused by a shift, the continuously variable transmission controller is controlled by a continuously variable transmission control time constant T._CVTIs set to 0.8 sec, which is slower than 0.5 sec.
[0074]
As described above, the continuously variable transmission control time constant T_CVTBy switching the switch according to the running state, it is possible to provide a speed change characteristic suitable for the driver. Also, a time constant T that determines the dynamic characteristics of the transmission_CVTIs configured to improve the responsiveness when the constant speed running control is interrupted and resumed and to reduce the shift shock of the transmission, so only one type of shift control map is required for constant speed running. Therefore, as compared with the conventional switching between two types for constant speed driving and for interruption (normal driving), less memory is required, and the transmission map and vehicle speed control device Since a map having the same characteristics can be used as the map 544 for design, the design is facilitated.
[0075]
Further, the vehicle speed control interruption determination unit 620 stops the output of the vehicle speed control interruption signal when the accelerator operation amount AP0 returns below a predetermined value, and the vehicle speed V_A(t) is the vehicle speed specified maximum value V_SMAXIf greater than, a deceleration request is output to the drive torque command value calculation unit 530. When the output of the vehicle speed control interruption signal from the vehicle speed control interruption determination unit 620 is stopped and a deceleration request is input, the driving torque instruction value calculation unit 530 calculates the calculated driving force instruction value d._FC(t) is controlled to decelerate at the throttle opening calculated by the target throttle opening calculation unit 570 so as to be realized by the throttle, but when the braking force is insufficient only by fully closing the throttle, the throttle and the gear ratio The gear ratio command value DRATIO (shift down request) is output from the gear ratio command value calculation unit 540 regardless of whether it is a downhill road or a flat road, so that the downshift control of the continuously variable transmission 70 is performed. Control to compensate for the lack of braking force.
[0076]
Also, a driving (braking in this case) force command value d_FCWhen (t) is large and the braking force due to the downshift of the continuously variable transmission is at the upper limit, the braking force is supplemented by normal braking on a flat road, but on the downhill road, the braking torque is calculated from the drive torque command value calculation unit 530. Brake control prohibition signal B to command value calculation unit 630_PIs output, thereby prohibiting brake control on downhill roads. The reason for controlling in this way is as follows. That is, on a downhill road, if the brake is decelerated, it is necessary to continuously apply the brake, which may cause problems such as brake fade. For this reason, as described above, on downhill roads, braking is performed without using a brake by controlling to obtain the required braking force only by throttle opening and deceleration by downshift control of the continuously variable transmission. Yes.
[0077]
Even if the driver temporarily decelerates the accelerator pedal and accelerates the constant speed running control by the above method and then returns to the constant speed running control again, the transmission shifts down, Since it becomes possible to obtain a deceleration larger than the deceleration of only the throttle opening fully closed control, the convergence time to the target vehicle speed can be shortened. Further, by using a continuously variable transmission, there is no shift shock even on a long downhill, and the vehicle speed command value change amount ΔV is greater than the deceleration of only the throttle opening fully closed control._COMSince the throttle and the gear ratio are controlled so as to realize the drive torque based on (t), the vehicle can be smoothly decelerated while maintaining a predetermined deceleration. Since a shock occurs at the time of downshifting in an ordinary stepped transmission, conventionally only throttle control is performed even when the deceleration control request is large as described above, and transmission downshift control is not performed. However, if the continuously variable transmission is used, the downshift can be performed smoothly. Therefore, by performing the control as described above, it is possible to smoothly decelerate with a large deceleration greater than the deceleration only for the throttle opening fully closed control.
Next, vehicle speed control stop processing will be described.
The driving wheel acceleration calculation unit 600 of FIG._A(t) is input, and the driving wheel acceleration α_OBS(t) is calculated.
α_OBS(t) = [K_OBS・ S / (T_OBS・ S²+ S + K_OBS)] ・ V_A(t)
However, K_OBSIs a constant, T_OBSIs a time constant.
The above vehicle speed V_ASince (t) is a value calculated from the rotation speed of the tire (drive wheel) as described above, this value itself is a value corresponding to the rotation speed of the drive wheel, and the drive wheel acceleration α described above._OBS(t) is the drive wheel speed V_AThis is a value obtained by determining the amount of change in vehicle speed (drive wheel acceleration) from (t).
[0078]
Then, the vehicle speed control stop determination unit 610 determines the driving wheel acceleration α obtained by the driving wheel acceleration calculation unit 600._OBS(t) is compared with a predetermined acceleration limit value α (this acceleration is a value corresponding to the amount of change in the vehicle speed, for example, 0.2 G), and the driving wheel acceleration α is compared._OBSWhen (t) exceeds the acceleration limit value α, a vehicle speed control stop signal is output. In response to the vehicle speed control stop signal, the drive torque command value calculation unit 530 and the target throttle opening calculation unit 570 initialize the calculation. Note that once the vehicle speed control is stopped, the vehicle speed control does not return until the set switch 20 is turned on again.
[0079]
The apparatus of FIG. 1 has a vehicle speed command value change amount ΔV determined by a vehicle speed command value change amount determination unit 590._COMSince the vehicle speed is controlled by the vehicle speed command value based on (t), the vehicle speed command value change amount limit value [for example, 0.06G = 0.021 (km / h) / 10 (ms )] Does not change. Therefore, driving wheel acceleration α_OBSWhen (t) exceeds a predetermined acceleration limit value α (for example, 0.2 G) that is larger than the value corresponding to the vehicle speed command value change amount limit value, there is a possibility that slip has occurred in the drive wheels. high. Thus, driving wheel acceleration α_OBSThe occurrence of slip can be detected by comparing (t) with a predetermined acceleration limit value α. For this reason, a normal vehicle speed sensor (the rotational speed of the driving wheel) can be used without separately providing an acceleration sensor with a slip suppression device such as a TCS (traction control system) or detecting the difference in rotational speed between the driving wheel and the driven wheel. Drive wheel acceleration α with the output from the sensor_OBSTherefore, it is possible to make a slip determination and a control stop determination. Further, the vehicle speed command value change amount ΔV_COMBy increasing (t), the response to the target vehicle speed can be improved. Drive wheel acceleration α_OBSInstead of determining whether to stop the constant speed traveling control from the comparison between (t) and a predetermined value, the vehicle speed command value change amount ΔV calculated by the vehicle speed command value change amount determination unit 590 is calculated._COM(t) and driving wheel acceleration α_OBSThe control may be stopped when the difference from (t) exceeds a predetermined value.
[0080]
Further, in the vehicle speed command value determination unit 510 of FIG._COM(t) is the input vehicle speed V_AWhen it is higher than (t) and changes in the deceleration direction (V_SMAX<V_AWhether or not). And vehicle speed command value V_COM(t) is the vehicle speed V_A(t) or lower predetermined speed V_COM(t) (for example, a value obtained by subtracting 5 km / h from the own vehicle speed) and C in the drive torque command value calculation unit 530 shown in FIG.₂(s) ・ V_A(t) -C₁(s) ・ d_FC(t) = d_VC so that the output of (t) is zero.₂(s) and C₁The initial value of the integrator in (s)_A(t). This result C₁The output of (s) is also C₂The output of (s) is also V_A(t), resulting in disturbance estimate d_V(t) is zero.
Furthermore, as a timing for performing the above-described control, V_COMΔV which is the rate of change of (t)_COMAssume that (t) is larger than the predetermined value (0.06G) on the deceleration side. As a result, unnecessary initialization (V_A(t) → V_COMSince (t) initialization and integrator initialization) are reduced, deceleration shock is reduced.
As described above, when the vehicle speed command value (incremental control command value until reaching the target vehicle speed) is larger than the actual vehicle speed and the temporal change of the vehicle speed command value changes in the deceleration direction, the vehicle speed command value Can be quickly converged to the target vehicle speed by changing to a predetermined vehicle speed equal to or less than the actual vehicle speed. Further, the continuity of the control can be maintained by initializing the drive torque command value calculation unit 530 using the set actual vehicle speed or a vehicle speed lower than that.
[0081]
In the vehicle speed control device that controls the actual inter-vehicle distance to match the target inter-vehicle distance so that the vehicle travels with the target inter-vehicle distance set by the driver, the vehicle speed command value is the target inter-vehicle distance. In this case, the actual inter-vehicle distance is equal to or less than a predetermined value, and the vehicle speed command value change amount ΔV is set._COMWhen (t) is larger than the predetermined value (0.06G) on the deceleration side, the vehicle speed command value V_COMChange of (t) [V_A(t) → V_COM(t)] and a drive torque command value calculation unit 530 (specifically, an integrator therein) are initialized. With this configuration, it is possible to quickly converge to the target inter-vehicle distance, so that there is no possibility of being too close to the preceding vehicle, and continuity of control can be maintained. This also eliminates unnecessary initialization [V_A(t) → ΔV_COMSince (t) initialization and integrator initialization) are reduced, deceleration shock is reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the overall configuration of a vehicle speed control device of the present invention.
FIG. 2 is a block diagram showing a configuration of a lateral G vehicle speed correction amount calculation unit 580;
[Fig. 3] Vehicular speed V_AAnd FIG. 6 is a characteristic diagram showing the relationship between the low-pass filter cutoff frequency fc.
FIG. 4 Vehicle speed correction amount V_SUBCorrection coefficient for calculating (t) and lateral Y value Y_GThe characteristic view which shows the relationship with (t).
FIG. 5: Natural frequency ω_nSTRAnd own vehicle speed V_AThe characteristic view which shows the relationship.
[Fig. 6] Own vehicle speed V_A(t) and vehicle speed command maximum value V_SMAXThe absolute value of the deviation from the vehicle speed command value change amount ΔV_COMThe characteristic view which shows the relationship with (t).
7 is a block diagram showing a configuration of a drive torque command value calculation unit 530. FIG.
FIG. 8 is a diagram showing an example of an engine nonlinear steady characteristic map.
FIG. 9 is a diagram showing an example of a throttle opening degree estimation map.
FIG. 10 is a diagram showing an example of a CVT shift map.
FIG. 11 is a diagram showing an example of an overall engine performance map.
12 is a block diagram showing another configuration example of the drive torque command value calculation unit 530. FIG.
13 is a block diagram showing the contents of a gear ratio command value calculation unit 540 and a continuously variable transmission 70. FIG.
14 is a block diagram showing the contents of a throttle controller 575. FIG.
FIG. 15 is a map used when obtaining a vacuum (VAC) / vent (VENT) drive signal Duty (t).
[Explanation of symbols]
10 ... Vehicle speed sensor 20 ... Set switch
30 ... coast switch 40 ... accelerate switch
50 ... Brake actuator 60 ... Throttle actuator
70 ... continuously variable transmission 71 ... changeover switch
72: Low-pass filter unit 73: Shift map
74 ... Rotation speed LIMIT part 75 ... Speed ratio command value calculation part
76 ... Servo unit 80 ... Engine rotation sensor
90 ... accelerator pedal sensor 100 ... steering angle sensor
500: Vehicle speed control unit 510: Vehicle speed command value determination unit
520 ... Vehicle speed command maximum value setting unit 530 ... Drive torque command value calculation unit
540 ... Transmission ratio command value calculation unit 541 ... Throttle opening degree estimation map
542 ... Brake engine speed command value calculation map
543 ... changeover switch 544 ... shift map
545 ... Number of revolutions LIMIT part 546 ... Number of revolutions LIMIT part
547 ... changeover switch 548 ... gear ratio command value calculation unit
549 ... Low-pass filter unit 550 ... Actual gear ratio calculation unit
560 ... Engine torque command value calculation unit 570 ... Target throttle opening calculation unit
575 ... Throttle controller 580 ... Lateral G vehicle speed correction amount calculation unit
581: Steering angle signal LPF unit 582 ... Lateral G calculation unit
583 ... Vehicle speed correction amount calculation map 590 ... Vehicle speed command value change amount determination unit
600: Driving wheel acceleration calculation unit 610: Vehicle speed control stop determination unit
620 ... Vehicle speed control interruption determination unit 630 ... Brake pressure command value calculation unit
V_A(t) ... Vehicle speed V_SMAX... Maximum vehicle speed command
θ (t): Steering angle V_SUB(t) ... Vehicle speed correction amount
θ_LPF(t) Steering angle LPF value V_COM(t) ... Vehicle speed command value
ΔV_COM(t) ... Vehicle speed command value change amount d_FC(t) ... Drive torque command value
d_V(t) ... Disturbance estimate
d_V(t) ′: Driving torque command value correction amount
d_FA(t) ... Actual drive torque C_F(s): Precompensator
C_R(s) ... Standard model calculation unit
d_FC1(t) ... Reference drive torque command value
C₁(s), C₂(s), C₃(s) ... Compensator
C₃(s) ’… Feedback compensator
s ... Differential operator fc ... LPF cutoff frequency
Y_G(t): Horizontal G value ψ: Yaw rate
ω_nSTR... Natural frequency of vehicle response to steering angle
α_OBS(t) ... Drive wheel acceleration
TVO_ESTI... Throttle opening estimated value
TVO_COM... Target throttle opening APO ... Accelerator operation amount
N_{IN_COM}... Engine speed command value
DRATIO (t) ... Gear ratio command value T_CVT... Continuous transmission control time constant
TE_COM(t) ... Engine torque command value
TE_COM′… Engine brake torque
REF_PBRK(t) ... Brake pressure command value B_P... Brake control prohibition signal

Claims (6)

A throttle opening command value is calculated so as to eliminate the deviation between the actual vehicle speed and the target vehicle speed, a drive signal is calculated based on the throttle opening command value, and a throttle actuator for adjusting the throttle opening is driven by the drive signal. In the vehicle speed control device that performs constant speed traveling control so as to travel at the target vehicle speed,
Means for calculating a throttle opening equivalent value corresponding to an actual throttle opening that compensates for a response delay in the throttle actuator , using a control model that takes into account the response of the throttle actuator from the drive signal of the throttle actuator;
Means for interrupting the cruise control when the value of the throttle opening degree corresponding to the operation amount of the accelerator pedal, is larger than the throttle opening angle values,
A vehicle speed control device comprising:   The vehicle speed control device according to claim 1, wherein the throttle actuator is a negative pressure type actuator using negative pressure as a power source. When the driving force for eliminating the deviation between the actual vehicle speed and the target vehicle speed is insufficient in the control based on the throttle opening command value, the first shift command is calculated based on a predetermined first shift control map. Means,
A transmission having a response characteristic at the time of a shift determined by a variable time constant within a predetermined range, and a second shift control map having the same characteristics as the first shift control map,
The transmission is controlled based on the first shift command and the response characteristic during constant speed running control, and the second speed change based on an accelerator pedal depression amount when constant speed running control is interrupted. the control map as well as calculating a second shift command, switches the time constant that determines the response characteristic, the second shift command and the time constant is controlled by the response characteristics are switched, that The vehicle speed control device according to claim 1 or 2, characterized in that   4. The vehicle speed control device according to claim 3, wherein the switching of the time constant is performed such that the time constant is smaller at the time of interruption than at the time of constant speed traveling control.   5. The vehicle speed control device according to claim 3, wherein the switching of the time constant is performed based on an input of an interruption time signal indicating an interruption time of constant speed traveling control and an accelerator pedal operation direction. .   The direction of the accelerator pedal operation is the direction to depress the accelerator pedal and the direction to return, and the time constant switching is smaller when the accelerator is depressed and when the accelerator is depressed than when the constant speed running control is performed. 6. The vehicle speed control device according to claim 5, wherein the time constant is switched so that the time constant is increased when the time and the accelerator are returned.

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