JP3985595B2

JP3985595B2 - Driving control device for automobile

Info

Publication number: JP3985595B2
Application number: JP2002173560A
Authority: JP
Inventors: 和彦佐藤; 利通箕輪; 智倉垣; 徳治吉川; 枝穂泉; 隆生児島
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2002-06-14
Filing date: 2002-06-14
Publication date: 2007-10-03
Anticipated expiration: 2022-06-14
Also published as: JP2004017731A

Description

【０００１】
【発明の属する技術分野】
本発明は自動車の走行制御装置に関し、特に前方の道路が凍結，海岸砂の堆積等で路面摩擦係数が低いと予測される場合に、後続車から追突される可能性を低減しつつ、スリップする確率を低減できる速度へ制御可能な自動車の走行制御装置に関連する。
【０００２】
【従来の技術】
従来、高速道路などを走行する場合に、アクセル操作をしなくても運転者が設定した速度で自動的に走行することができるクルーズコントロールシステムが開発されている。
【０００３】
また、上記システムにさらに環境認識センサを備え、自車両と先行車両（含む障害物など）との距離や相対速度を検出し、アクセル操作，ブレーキ操作をしなくても、所定の車間距離を保持しながら走行することができる車間距離制御クルーズコントロールシステム（以下「ＡＣＣ」とする）が開発され実用化されている。
【０００４】
また、先行車両だけでなく、後続車両の動向に対応した走行制御技術が開示されている。たとえば特開平７−１７２２０８号公報では自車と先行車との車間距離を検出する第１レーダ装置と、自車と後続車との車間距離を検出する第２レーダ装置と、自車と先行車との車間距離を所定の目標車間距離に保つよう車速を制御するコントロールユニットとを備え、後続車が自車に所定の距離より近付いているときの目標車間距離を、後続車が所定の距離より離れているときのそれよりも長く設定し、また、後続車が自車に対し所定の距離より近付いているときに先行車が減速した時は、後続車が所定の距離より離れているときに先行車が減速した時に比べて緩やかに減速するといった技術が開示されている。
【０００５】
【発明が解決しようとする課題】
上記従来技術は基本的に先行車両との関係と自車の設定車速とにより速度制御を実施するシステムであり、すべての走行場面を考えた場合、常に後続車に追突される可能性が０であるわけではない。たとえば自車が何らかの方法で前方の道路に路面凍結などの障害があるという情報を入手した場合、自車はその障害地点に到達するまでに、その障害による事故の可能性を充分低減可能な速度に減速することができる。しかし後続車はその障害に関する情報を入手しているとは限らない。その場合、自車は障害地点への到達に備え、たとえ、前方に先行車，障害物，信号，一時停止標識などが無くても減速開始する場合があり得るが、追従している後続車の運転者は上記のような減速あるいは停止する理由が何も無いような場所と思いながら走行しているところに、突然先行車が目標速度に向かって減速開始するため、減速方法や車間距離によっては後続車の運転者の反応が遅れる等して追突される可能性が全くないというわけではない。
【０００６】
本発明は上記事情に鑑みなされたものであり、前方の道路が凍結，海岸砂の堆積等で路面摩擦係数が低いと予測される場合に、後続車から追突される可能性を低減しつつ、スリップする確率を低減できる速度に制御可能な、より安全性が向上した自動車の走行制御装置の提供を目的としている。
【０００７】
【課題を解決するための手段】
本発明は、センサにより前記後続車との車間距離を入力する後続車情報入力手段と、今後走行する経路の路面摩擦係数を求め、当該路面摩擦係数に基づき当該経路の所定の地点におけるスリップ低減速度を求めるスリップ低減速度推定手段と、スリップ低減速度推定手段で求めた前記スリップ低減速度と、自車の現在地点と前記所定の地点との間の距離と、自車現在速度と、前記後続車情報入力手段で得た前記後続車との車間距離に基づいて段階的に減速する速度指令値パターンを求める速度指令値演算手段と、前記速度指令値演算手段で求めた速度指令値パターンに応じて自車の速度を制御する速度制御手段と、を有する自動車の車両走行制御装置である。
【０００８】
好ましくは、前記速度制御手段は、前記速度指令値演算手段で求めた減速パターンに応じて、エンジンスロットル、変速機、ブレーキの少なくともいずれか一つを用いて自車の速度を制御することである。
【０００９】
好ましくは、スリップ低減速度推定手段は、入力した地図情報及び自車位置情報に基づいて今後走行する経路を予測し、当該経路の路面摩擦係数を求め、当該路面摩擦係数に基づき当該経路の所定の地点におけるスリップ低減速度を求めることである。また好ましくは、前記スリップ低減速度推定手段は、自車の現在位置情報の変化に基づいて今後走行する経路を予測し、当該経路の路面摩擦係数を求め、当該路面摩擦係数に基づき当該経路の所定の地点におけるスリップ低減速度を求めることである。また好ましくは、前記スリップ低減速度推定手段は、運転者が事前に設定した経路の路面摩擦係数を求め、当該路面摩擦係数に基づき当該経路の所定の地点におけるスリップ低減速度を求めることである。また好ましくは、前記スリップ低減速度推定手段は、今後走行する経路の路面摩擦係数を、当該経路を含む地域の天候履歴情報に基づいて求め、当該路面摩擦係数に基づき当該経路におけるスリップ低減速度を求めることである。また好ましくは、前記スリップ低減速度推定手段は、今後走行する経路の路面摩擦係数を求め、当該路面摩擦係数に基づき当該経路の所定の地点におけるスリップ低減速度を求めるとともに、当該スリップ低減速度が当該経路の法定速度よりも高い場合は、当該法定速度をスリップ低減速度として設定することである。
【００１０】
好ましくは、前記速度指令値演算手段は、スリップ低減速度推定手段で求めた前記スリップ低減速度と、自車の現在地点と前記所定の地点との間の距離と、自車現在速度と、前記後続車情報入力手段で得た前記後続車情報とに基づいて段階的に減速する速度指令値パターンを求めるとともに、先行車の減速や走行路の急カーブに基づく速度指令値と前記速度指令値パターンに基づく速度指令値のうち、より低い速度指令値を出力することである。また好ましくは、前記速度制御手段による制御中に運転者のペダル操作があった場合は、当該ペダル操作による速度制御が優先されることである。また好ましくは、速度指令値演算手段は、スリップ低減速度推定手段で求めた前記スリップ低減速度と、自車の現在地点と前記所定の地点との間の距離と、自車現在速度と、前記後続車情報入力手段で得た前記後続車情報とに基づいて、前記自車現在速度よりも小さく、前記スリップ低減速度よりも大きい過渡速度を少なくとも一つ設定し、前記自車現在速度、前記過渡速度、前記スリップ低減速度の順で段階的に減速する速度パターンを求めることである。
【００１１】
また好ましくは、前記速度指令値演算手段により演算された速度指令値に基づき後続車に自車の減速を報知する報知制御手段を有することである。
【００１２】
好ましくは、自車の後部に後続車への報知灯をさらに備え、前記スリップ低減速度による速度制御に加え、さらにスリップ低減速度以下の速度での走行が必要な区間に到達するまでの間に、間欠的に前記報知灯を作動させることを特徴とする自動車の走行制御装置であれば良い。
【００１３】
好ましくは、走行環境情報とステアリング舵角に応じ車輪に独立に制動力を付加する独立輪制動力付加手段の機能作動−機能非作動を自動的に選択する独立輪制動力付加手段自動選択手段をさらに備え、前記スリップ低減速度による速度制御に加え、さらにスリップ低減速度以下の速度での走行が必要な区間に到達するまでの間に前記独立輪制動力付加手段自動選択手段により独立輪制動力付加手段を自動的に機能することを特徴とする自動車の走行制御装置であれば良い。
【００１４】
好ましくは、走行環境情報により自車の駆動輪数を自動的に選択する駆動輪自動選択手段をさらに備え、前記スリップ低減速度による速度制御に加え、さらにスリップ低減速度以下の速度での走行が必要な区間に到達するまでの間に自車の駆動輪を４輪駆動に自動的に変更することを特徴とする自動車の走行制御装置であれば良い。
【００１８】
【発明の実施の形態】
以下、本発明の実施の形態を説明するが、本発明はこれらに限定されるものではなく種々の応用が可能である。
【００１９】
図１は本発明の一実施形態に係る、自動車の走行制御装置の全体構成を示す。図１はスリップ低減速度推定手段（図３で説明），経路推定手段，速度指令演算手段，速度制御手段，報知制御手段，エンジンスロットル，変速機，ブレーキ，後続車報知装置からなる。速度指令演算手段は種々の環境情報や車両情報の入力により速度指令値を演算する機能を有する。基本的には運転者が設定する設定速度が基準となり、自車速度が設定速度となるように速度指令値が演算され速度制御手段によりエンジンスロットル，変速機を制御する。ここに、さらにセンサにより後続車速度，後続車との車間距離，先行車速度，先行車との車間距離，ヨーレート，横Ｇなどの自車運動情報が入力され、かつ速度制御手段によりブレーキも制御することにより、後続車や先行車の走行状況に応じた速度制御が可能となる。さらに、地図・暦情報，自車位置情報を入力することにより、経路推定手段により経路が推定される。また、経路推定手段では、経路の地形、たとえば急カーブや料金所などがあった場合に、それに応じた速度情報を速度指令値演算手段に伝えることにより適切に速度制御できる。また、この経路は運転者操作により事前に設定することもできる。
【００２０】
また、経路を含む地域の天候履歴情報をスリップ低減速度推定手段に入力することにより、今後走行する経路で路面凍結、あるいは砂の飛散・堆積などにより路面摩擦係数が低下（低μ）しているかどうかを推定する。その推定した路面摩擦係数に基づき、その地点の走行時にスリップする確率を低減できる速度、すなわちスリップ低減速度を推定し速度指令値演算手段に情報を伝える。このようにして上記のような低μ路面においても適切な速度指令値が演算され、スリップ低減できる速度に制御できる。この場合、後続車がいる場合には追突される確率を低減できる速度制御を実施する。この速度制御の詳細については図５において説明する。また、速度指令値演算手段により演算された速度指令値により報知制御手段が後続車に自車の減速を報知する。これによりさらに追突される確率を低減できる。この場合の報知方法としては通常のブレーキランプによる報知でも良いが、天候履歴による減速時など、後続車が予期しているかどうかわからない場合にはブレーキランプとは別な方法で報知するようにした方が、後続車により注意を喚起できる場合がある。たとえば法規制の範囲内において、この場合にのみ点灯あるいは点滅する別なランプを設けるとか、あるいはランプの色をブレーキランプとは別な色にしても良い。
【００２１】
図２は本発明の一実施形態に係る、制御フローチャートである。この制御はたとえば１ｍｓなどの時間間隔で繰り返し実行されるものである。ここではスリップ低減速度による速度制御について説明する。まずスタート後、処理２０１により自車の現在位置を検出する。つぎに処理２０２により自車の現在速度を検出する。つぎに処理２０３にて地図・暦データを抽出する。この処理では自車位置を中心として、たとえば半径２０km付近の地図情報を検出する。また、同時に現在の日付、時刻および自車位置における太陽位置、あるいは海水の潮位などを抽出する。つぎに処理２０４では処理２０１の現在位置情報の変化をもとに走行経路を予測する。この場合、図１でも説明したように、運転者が事前に走行経路を設定しても良い。つぎに処理２０５では処理２０４の走行経路予測に基づき、その走行経路を含む地域の天候履歴情報を検出する。この天候履歴情報は、たとえば降水量，気温，湿度，風速などの履歴である。この検出した天候履歴情報および暦情報による太陽位置，地図の情報により走行経路が日陰になっているか、あるいは風により海岸の砂が道路上に飛散・堆積されてないかを推定する。以上の情報を元に処理２０６で路面の状態を判定しスリップ低減速度を推定する。つぎに処理２０７，２０８では推定したスリップ低減速度について妥当なものかどうかを判定する。まず処理２０７ではスリップ低減速度がその経路の最高速度より低いかどうかを判定する。低い場合は処理２０８に進むが低くない場合は処理210により最高速度をスリップ低減速度に設定して処理２１１に進む。つぎに処理２０８ではスリップ低減速度が現在速度よりも低いかどうかを判定する。低い場合は処理２１１に進むが低くない場合は処理２０９により現在速度をスリップ低減速度に設定して処理２１１に進む。また、処理２０９ではスリップ低減速度による制御は必要ないという判断からスリップ低減速度を設定せず、他の速度指令による制御を継続するようにしても良い。つぎに処理２１１では後続車との車間距離を検出する。ここで同時に後続車の速度を検出しても良い。つぎに処理212ではスリップ低減速度が必要な地点までの距離を演算する。そして処理２１３で実際の速度指令値を演算する。以上はスリップ低減速度による速度指令値演算である。速度指令はスリップ低減速度の他にも、先行車が減速した場合、急カーブにさしかかった場合などにより速度指令値が演算される場合もある。そういった時のために処理２１４により最も低い速度指令値の判定を実施する。ここで、最も低い速度指令値であった場合には処理２１５に進み、速度指令値に基づく速度制御が実施される。最も低い速度指令値でなかった場合は何もせず処理を終了する。以上のような制御フローによりスリップ低減速度による速度制御が実施される。また、この速度制御の最中に運転者によるペダル操作があった場合は常にそちらが優先される。
【００２２】
図３は本発明の一実施形態に係る、スリップ低減速度推定手段（図１）のブロック図を示す。図３に示すようにスリップ低減速度は天候履歴情報と地図・暦データにより推定される。まず、天候履歴情報としては気温履歴，降水量履歴，湿度履歴，風速・風向履歴を用いる。また、地図・暦データから、太陽位置・高度，地図データ，潮位などのデータを入手する。ここで、地図データには道路の緯度経度情報の他に道路脇の建造物の高さ、あるいは山の高さなどの情報も含まれている。これらの地図・暦データにより走行経路の日射量、具体的には走行経路が日陰になっているかどうかが演算される。また同時に走行経路で海岸砂が飛散しやすいかどうかが演算される。これについては図７で説明する。このようにして路面摩擦係数（μ）が推定され、推定値に基づきスリップ低減速度が演算される。
【００２３】
図４は本発明の一実施形態に係る、天候履歴の活用により路面凍結が予測される状況図を示す。図４は地域４０１，経路４０２，太陽４０３，山４０４，山の陰４０５,区間４０６,自車４０７より構成される。また、図４の下に地域４０１の天候履歴情報と区間４０６の日射量情報とを示す。自車は時刻ｔ０で図の位置におり、経路４０２に沿って走行中である。このとき天候履歴情報を検索する。降水量履歴により地域４０１では午前０時少し前から３時過ぎまでに雨が降ったというデータを得た。また気温履歴により気温は日の出前に０℃近くまで冷え込んだという履歴を示している。また区間４０６は日の出から１１時近くまでは山４０４の日陰になってしまい、時刻ｔ０付近では日射量が得られないというデータを示している。これらのデータにより時刻ｔ０における区間４０６では高い確率で路面凍結が予想される。また、この時に経路４０２の道路構造によりある程度求められる、道路上の水分の単位時間あたりの染み込み量を路面凍結予測のためのパラメータに加えれば、気温低下時の路面上の水分量をある程度予測できるため、路面凍結予測精度が向上するのでより効果的である。
【００２４】
図５は本発明の一実施形態に係る、天候履歴により路面凍結が予測された場合の自車速度制御のタイムチャートを示す。図５は地域４０１，経路４０２，太陽４０３，山４０４，山の陰４０５，区間４０６，自車４０７，後続車４０８，自車の時刻ｔ１での地点４０９,時刻ｔ２での地点４１０,時刻ｔ３での地点４１１，時刻ｔ４での地点４１２，時刻ｔ５での地点４１３，時刻ｔ６での地点４１４より構成される。ここでは図４と同様、区間４０６に凍結が予測される場合の例について説明する。自車は約６０km／ｈで経路４０２を走行している。図の407の位置において区間４０６の凍結推定によりスリップ低減速度を１５km／ｈと推定し、速度制御を実施しようとしているが、後方に後続車４０８が所定の車間距離で追従しているため、段階的に減速制御を実施する。まず地点４０９から410の区間において６０km／ｈから４０km／ｈに減速している。約２０km／ｈの減速により後続車との相対速度の開きを少なくし、追突される確率を低くしている。その後地点４１０から４１１までの区間は時速４０km／ｈで定速走行している。そして地点４１１から４１２までの区間において時速４０km／ｈからこの場合のスリップ低減速度である１５km／ｈに減速している。そして区間４０６を含む、地点４１２から４１３の区間は１５km／ｈで定速走行し、区間４０６を通過する。そして地点４１３から４１４の区間は再び加速し最終的に６０km／ｈに到達している。このように段階的に減速制御することにより後続車との相対速度の開きを少なくし、追突される確率を低減することができる。なお、減速パターンは後続車との車間距離，自車速度，推定したスリップ低減速度，スリップ低減速度が必要な地点までの距離に応じ、随時変更される。また、減速は２段階とは限らず３段階以上の減速パターンを選択しても良い。また、図１の説明でも述べたように報知制御手段により後続車に自車の減速を報知しても良い。これによりさらに追突される確率を低減できる。
【００２５】
このような減速パターンを取らない場合の速度制御タイムチャートの比較実施例を図６に示す。走行環境は図５と同様である。まず減速パターン６０１は地点４１１付近（時刻ｔ３′）から地点４１２（時刻ｔ４）の区間で６０km／ｈからスリップ低減速度である１５km／ｈまで一気に減速している。このような減速パターンでは相対速度が最大４５km／ｈまで開く可能性があるので後続車に追従されている場合は追突される可能性が全く０とは言い切れない。なぜなら、後続車は自車と同様に区間４０６の凍結を予測しているとは限らず、自車の減速を事前に予知できない。また、見通しの良い広い道路で、歩行者，自転車，信号などが無い場合では後続車の運転者は自車が減速・停止するはずが無いと思い込み、油断が生じる場合がある。そのような場合に自車がパターン６０１のような減速をしてしまうと、後続車は不意をつかれてしまい、ブレーキペダル操作遅れやペダル操作ミスなどを引き起こし、追突してしまう可能性が全く０とは言い切れない。また減速パターン６０２では地点４０９付近（時刻ｔ１′）から地点４１２（時刻ｔ４）までの区間で、緩い減速度により６０km／ｈからスリップ低減速度である１５km／ｈまで減速している。このような減速パターンの場合はパターン６０１に比べ、減速度が緩いため後続車に追突される確率は低くなる。しかしこの場合は減速期間が時刻（ｔ４−ｔ１′）とパターン６０１に比べて長くなってしまう。このような場合、後続車の運転者は自車が停止するものと勘違いを起こし、自車を追い越してしまう可能性が考えられる。その場合、追い越す時に運転ミスなどで自車・対向車との接触・衝突などを起こし自車が巻き込まれる可能性が０であるとは言い切れない。また、無事に追い越しても後続車が区間４０６をスリップ低減速度以上の速度で突入してしまい、スリップを起こす可能性もある。このように後続車自身や自車にとっても上述したように、好ましい減速パターンとは言えない。この点、図５に示す減速パターンは１回の減速期間が短いため後続車の運転者は自車が停止すると考える可能性は低く、追い越す可能性も低くなる。また相対速度の開きが少ないため不意をつかれても危険な状態に陥る可能性は少なく、より安全な減速パターンと考えられる。
【００２６】
図７は本発明の一実施形態に係る、天候履歴の活用により海岸砂の飛散・堆積が予測される状況図を示す。図７は地域７０１，経路７０２，自車７０３，建造物７０４ａ〜ｅ，海７０５，砂浜７０６，区間７０７より構成される。また、図７の下に地域７０１の天候履歴情報と区間ＡＢの地図情報を示す。自車は時刻ｔ０で図の位置におり、経路７０２に沿って走行中である。このとき天候履歴情報を検索する。降水量履歴により地域７０１では午前４時ころに少量の雨が降ったというデータを得た。また風速・風向履歴により午前９時から１２時過ぎまでに海方向から強風が吹いたとのデータを得た。また、上記強風が吹いた時間帯には潮位がちょうど干潮の前後であったというデータを得た。また区間７０７では海岸までの距離が近く、また建造物は無いというデータが得られた。すなわち、区間７０７は海岸に面しているということを示している。これらのデータにより時刻ｔ０における区間７０７では高い確率で路面上の海岸砂の飛散・堆積が予想される。このようにして、海岸付近の通行の場合にも天候履歴情報を用い、海岸砂の飛散・堆積などによる路面摩擦係数低下を予測できる。そして路面凍結の場合と同様スリップ低減速度を推定し、後続車の状況に応じた速度制御を実現できる。
【００２７】
図８は本発明の一実施形態に係る、経路前方に障害がある場合の速度制御タイムチャートを示す。本実施例は路面摩擦係数の予測による速度制御だけでなく、事故など通行障害が発生した場合にも対応することができる。図８は経路８０１，自車８０２，後続車８０３,時刻ｔ１での地点８０４,時刻ｔ２での地点８０５，時刻ｔ３での地点８０６，時刻ｔ４での地点８０７，時刻ｔ５での地点８０８，時刻ｔ６での地点８０９，障害発生地点８１０より構成される。自車は約６０km／ｈで経路８０１を走行している。図の８０２の位置において何らかの手段で地点８１０の通行障害情報を入手した場合、最終的に徐行速度まで段階的に減速制御している。まず地点８０４から８０５までの区間において６０km／ｈから４０km／ｈに減速している。約２０km／ｈの減速により後続車との相対速度の開きを少なくし、追突される確率を低くしている。これは図５の場合と同様である。その後地点８０５から８０６までの区間は時速４０km／ｈで定速走行している。そして地点８０６から８０７までの区間において時速４０km／ｈから１５km／ｈに減速している。そして地点８０７から８０８までの区間では１５km／ｈで定速走行をしている。そして地点８０８から８０９までの区間において時速１５km／ｈから徐行速度に減速している。このようにして地点８１０に到達するまでに徐行速度まで減速しているので、たとえ上記通行障害により停止しなければならない場合であっても直ちに停止できる。
【００２８】
図９は本発明の一実施形態に係る、速度制御と独立輪制動力付加制御（以下ＶＤＣ）、または４輪駆動制御（以下４ＷＤ）を併用した場合のタイムチャートを示す。速度タイムチャートは図５の場合と同様である。本実施形態では、時刻ｔ３付近でＶＤＣまたは４ＷＤがＯＮになっている。これらの制御と併用することにより一層のスリップ低減効果が期待できる。なお、４ＷＤは機構的に走行中に変更できない場合があるので、その場合は運転者に４ＷＤへの変更を報知するだけでも良い。
【００２９】
なお、以上の実施形態に限ることなく、機能を損なわない範囲においてあらゆる変更が可能である。たとえば天候履歴情報により低μ情報を得た場合、スリップ低減速度の演算の前に自車の運転者に低μ情報を音声，表示などで報知するようにしても良い。
【００３０】
なお、本発明は上記各実施形態の構成に限定されるものではなく、本発明の範囲内であれば上記実施の形態の一部同士を組み合わせた構成としても良い。
【００３１】
【発明の効果】
本発明によれば、前方の道路が凍結，海岸砂の堆積等で路面摩擦係数が低いと予測される場合に、後続車から追突される可能性を低減しつつ、スリップする確率を低減できる速度に制御可能な、より安全性が向上した自動車の走行制御装置が提供できる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る、自動車の走行制御の全体構成を示す。
【図２】本発明の一実施形態に係る、制御フローチャートを示す。
【図３】本発明の一実施形態に係る、スリップ低減速度推定のブロック図を示す。
【図４】本発明の一実施形態に係る、天候履歴の活用により路面凍結が予測される状況図を示す。
【図５】本発明の一実施形態に係る、天候履歴により路面凍結が予測された場合の自車速度制御のタイムチャートを示す。
【図６】速度制御タイムチャートの比較実施例を示す。
【図７】本発明の一実施形態に係る、天候履歴の活用により海岸砂の飛散・堆積が予測される状況図を示す。
【図８】本発明の一実施形態に係る、経路前方に障害がある場合の速度制御タイムチャートを示す。
【図９】本発明の一実施形態に係る、速度制御とＶＤＣ、または４ＷＤの制御を併用した場合のタイムチャートを示す。
【符号の説明】
１…スリップ低減速度推定手段、２…経路推定手段、３…速度指令値演算手段、４…速度制御手段、５…報知制御手段、６…エンジンスロットル、７…変速機、８…ブレーキ、９…後続車報知装置。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automobile travel control device, and in particular, when a road ahead is frozen, coastal sand accumulation, or the like is predicted to have a low road surface friction coefficient, the vehicle slips while reducing the possibility of a rear-end collision. The present invention relates to an automobile travel control device that can be controlled to a speed that can reduce the probability.
[0002]
[Prior art]
Conventionally, a cruise control system has been developed that can automatically travel at a speed set by a driver without operating an accelerator when traveling on an expressway or the like.
[0003]
In addition, the above system is further equipped with an environment recognition sensor to detect the distance and relative speed between the host vehicle and the preceding vehicle (including obstacles) and maintain a predetermined distance between the vehicles without operating the accelerator or brake. An inter-vehicle distance control cruise control system (hereinafter referred to as “ACC”) that can travel while being developed has been developed and put into practical use.
[0004]
Further, a travel control technique corresponding to the trend of not only the preceding vehicle but also the following vehicle is disclosed. For example, in Japanese Patent Application Laid-Open No. 7-172208, a first radar device that detects an inter-vehicle distance between the host vehicle and a preceding vehicle, a second radar device that detects an inter-vehicle distance between the host vehicle and a following vehicle, and the host vehicle and a preceding vehicle. And a control unit that controls the vehicle speed so as to keep the inter-vehicle distance at a predetermined target inter-vehicle distance, and the target inter-vehicle distance when the following vehicle is closer to the own vehicle than the predetermined distance Set longer than that when the vehicle is far away, and when the preceding vehicle decelerates when the following vehicle is closer to the vehicle than the predetermined distance, A technique is disclosed in which the vehicle decelerates more slowly than when the preceding vehicle decelerates.
[0005]
[Problems to be solved by the invention]
The above prior art is a system that basically performs speed control based on the relationship with the preceding vehicle and the set vehicle speed of the own vehicle. When considering all the driving scenes, there is no possibility that the vehicle will always collide with the following vehicle. There is no reason. For example, if the vehicle obtains information that the road ahead has a fault such as road surface freezing in some way, the speed at which the vehicle can sufficiently reduce the possibility of an accident due to the fault before reaching the fault point. Can slow down. However, the following car does not always have information about the obstacle. In that case, in preparation for reaching the obstacle, the vehicle may start decelerating even if there is no preceding vehicle, obstacle, signal, stop sign, etc. ahead, but the following vehicle The driver suddenly starts to decelerate toward the target speed while driving while thinking that there is no reason to decelerate or stop as described above, so depending on the deceleration method and inter-vehicle distance This is not to say that there is no possibility of a rear-end collision due to a delayed response from the driver of the following vehicle.
[0006]
The present invention has been made in view of the above circumstances, and when the road ahead is frozen, coastal sand accumulation and the like, when the road surface friction coefficient is predicted to be low, while reducing the possibility of a rear-end collision, An object of the present invention is to provide a travel control device for an automobile that can be controlled to a speed that can reduce the probability of slipping and that has improved safety.
[0007]
[Means for Solving the Problems]
  The present invention provides a following vehicle information input means for inputting an inter-vehicle distance from the succeeding vehicle by a sensor, a road surface friction coefficient of a route to be traveled in the future, and a slip reduction speed at a predetermined point on the route based on the road surface friction coefficient. Slip reduction speed estimation means for obtaining the slip reduction speed obtained by the slip reduction speed estimation means, the distance between the current position of the own vehicle and the predetermined position, the current speed of the own vehicle, and the subsequent vehicle information A speed command value calculating means for obtaining a speed command value pattern for gradually decelerating based on an inter-vehicle distance obtained from the input means, and a speed command value pattern obtained by the speed command value calculating means. And a speed control means for controlling the speed of the vehicle.
[0008]
  Preferably, the speed control means controls the speed of the host vehicle using at least one of an engine throttle, a transmission, and a brake in accordance with a deceleration pattern obtained by the speed command value calculation means. .
[0009]
  Preferably, the slip reduction speed estimation means predicts a route to be traveled in the future based on the input map information and the vehicle position information, obtains a road surface friction coefficient of the route, and determines a predetermined route of the route based on the road surface friction coefficient. It is to obtain the slip reduction speed at the point. Further preferably, the slip reduction speed estimating means predicts a route to be traveled in the future based on a change in the current position information of the own vehicle, obtains a road surface friction coefficient of the route, and determines a predetermined route of the route based on the road surface friction coefficient. The slip reduction speed at the point is obtained. Preferably, the slip reduction speed estimation means obtains a road surface friction coefficient of a route set in advance by the driver, and obtains a slip reduction speed at a predetermined point on the route based on the road surface friction coefficient. Preferably, the slip reduction speed estimation means obtains a road surface friction coefficient of a route to be traveled in the future based on weather history information of an area including the route, and obtains a slip reduction speed in the route based on the road surface friction coefficient. That is. Further preferably, the slip reduction speed estimation means obtains a road surface friction coefficient of a route to be traveled in the future, obtains a slip reduction speed at a predetermined point of the route based on the road surface friction coefficient, and the slip reduction speed is determined by the route. Is higher than the legal speed, the legal speed is set as the slip reduction speed.
[0010]
  Preferably, the speed command value calculation means includes the slip reduction speed obtained by the slip reduction speed estimation means, a distance between the current position of the own vehicle and the predetermined point, the current speed of the own vehicle, and the subsequent Based on the following vehicle information obtained by the vehicle information input means, a speed command value pattern that gradually decelerates is obtained, and a speed command value based on the deceleration of the preceding vehicle and a sharp curve of the travel path and the speed command value pattern are obtained. The lower speed command value is output among the speed command values based on the speed command value. Preferably, when the driver operates the pedal during the control by the speed control means, the speed control by the pedal operation is given priority. Further preferably, the speed command value calculation means includes the slip reduction speed obtained by the slip reduction speed estimation means, a distance between the current position of the own vehicle and the predetermined position, the current speed of the own vehicle, and the subsequent Based on the following vehicle information obtained by the vehicle information input means, at least one transient speed that is smaller than the current vehicle speed and larger than the slip reduction speed is set, and the current vehicle speed and the transient speed are set. And determining a speed pattern that decelerates stepwise in the order of the slip reduction speed.
[0011]
  Preferably, the information processing apparatus further includes notification control means for informing the subsequent vehicle of deceleration of the host vehicle based on the speed command value calculated by the speed command value calculation means.
[0012]
Preferably, the vehicle further includes a warning light for the following vehicle at the rear of the host vehicle, and in addition to speed control by the slip reduction speed, until reaching a section where traveling at a speed lower than the slip reduction speed is required, Any driving control device for an automobile may be used as long as the notification lamp is operated intermittently.
[0013]
Preferably, the independent wheel braking force adding means automatic selection means for automatically selecting function activation-function non-operation of the independent wheel braking force addition means for independently applying braking force to the wheel according to the driving environment information and the steering angle. In addition to the speed control based on the slip reduction speed, the independent wheel braking force is added by the independent wheel braking force adding means automatic selection means until the vehicle reaches a section where traveling at a speed lower than the slip reduction speed is required. Any driving control device for an automobile may be used as long as the means functions automatically.
[0014]
Preferably, it further comprises drive wheel automatic selection means for automatically selecting the number of drive wheels of the host vehicle based on the travel environment information, and in addition to speed control based on the slip reduction speed, traveling at a speed equal to or lower than the slip reduction speed is required. Any driving control device for an automobile may be used as long as the driving wheel of the own vehicle is automatically changed to four-wheel driving before reaching a certain section.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these, and various applications are possible.
[0019]
FIG. 1 shows the overall configuration of an automobile travel control apparatus according to an embodiment of the present invention. FIG. 1 includes slip reduction speed estimation means (described in FIG. 3), route estimation means, speed command calculation means, speed control means, notification control means, engine throttle, transmission, brake, and subsequent vehicle notification device. The speed command calculating means has a function of calculating a speed command value by inputting various environmental information and vehicle information. Basically, the set speed set by the driver is used as a reference, the speed command value is calculated so that the host vehicle speed becomes the set speed, and the engine throttle and the transmission are controlled by the speed control means. Further, the following vehicle speed information such as the following vehicle speed, the following vehicle distance, the preceding vehicle speed, the preceding vehicle speed, the following vehicle distance, the yaw rate and the lateral G is input by the sensor, and the brake is also controlled by the speed control means. By doing so, it becomes possible to control the speed in accordance with the traveling conditions of the following vehicle and the preceding vehicle. Furthermore, the route is estimated by the route estimation means by inputting the map / calendar information and the vehicle position information. Further, in the route estimation means, when there is a landform of the route, for example, a sharp curve or a toll booth, the speed can be appropriately controlled by transmitting speed information corresponding to the topography to the speed command value calculation means. Further, this route can be set in advance by a driver's operation.
[0020]
Also, by inputting the weather history information of the area including the route to the slip reduction speed estimation means, whether the road surface friction coefficient has decreased (low μ) due to road surface freezing or sand scattering / deposition on the route to be driven in the future Estimate whether. Based on the estimated road surface friction coefficient, a speed that can reduce the probability of slipping when traveling at that point, that is, a slip reduction speed is estimated, and information is transmitted to the speed command value calculation means. In this manner, an appropriate speed command value is calculated even on the low μ road surface as described above, and the speed can be controlled to reduce the slip. In this case, when there is a following vehicle, speed control that can reduce the probability of a rear-end collision is performed. Details of the speed control will be described with reference to FIG. Further, the notification control means notifies the following vehicle of the deceleration of the own vehicle by the speed command value calculated by the speed command value calculation means. This can further reduce the probability of a rear-end collision. As a notification method in this case, normal brake lamp notification may be used, but if you are not sure whether the succeeding vehicle is expected, such as when deceleration due to weather history, you should notify by a method different from the brake lamp However, it may be possible to call attention by following vehicles. For example, another lamp that lights or blinks only in this case may be provided within the scope of laws and regulations, or the lamp may have a different color from the brake lamp.
[0021]
FIG. 2 is a control flowchart according to an embodiment of the present invention. This control is repeatedly executed at a time interval such as 1 ms. Here, the speed control by the slip reduction speed will be described. First, after starting, the current position of the host vehicle is detected by processing 201. Next, the current speed of the host vehicle is detected by processing 202. Next, map / calendar data is extracted in processing 203. In this process, for example, map information around a radius of 20 km is detected with the vehicle position as the center. At the same time, the current date, time, sun position at the vehicle position, seawater tide level, and the like are extracted. Next, in process 204, a travel route is predicted based on the change in the current position information in process 201. In this case, as described with reference to FIG. 1, the driver may set the travel route in advance. Next, in the process 205, based on the travel route prediction of the process 204, the weather history information of the area including the travel route is detected. This weather history information is, for example, a history of precipitation, temperature, humidity, wind speed, and the like. Based on the detected weather history information and the sun position and calendar information based on the calendar information, it is estimated whether the traveling route is shaded or whether the sand on the coast is scattered or deposited on the road by the wind. Based on the above information, the state of the road surface is determined in processing 206 to estimate the slip reduction speed. Next, in processes 207 and 208, it is determined whether or not the estimated slip reduction speed is appropriate. First, in process 207, it is determined whether or not the slip reduction speed is lower than the maximum speed of the route. If it is low, the process proceeds to process 208. If not, the maximum speed is set to the slip reduction speed by process 210 and the process proceeds to process 211. Next, in step 208, it is determined whether the slip reduction speed is lower than the current speed. If it is lower, the process proceeds to process 211. If not, the process proceeds to process 211 by setting the current speed to the slip reduction speed by process 209. Further, in the process 209, the control by the other speed command may be continued without setting the slip reduction speed from the judgment that the control by the slip reduction speed is not necessary. Next, in process 211, the inter-vehicle distance from the following vehicle is detected. Here, the speed of the following vehicle may be detected at the same time. Next, in process 212, the distance to the point where the slip reduction speed is required is calculated. In step 213, the actual speed command value is calculated. The above is the speed command value calculation based on the slip reduction speed. In addition to the slip reduction speed, the speed command value may be calculated when the preceding vehicle decelerates or approaches a sharp curve. For such a time, the lowest speed command value is determined by the process 214. If the speed command value is the lowest, the process proceeds to step 215, and speed control based on the speed command value is performed. If the speed command value is not the lowest, the process is terminated without doing anything. The speed control based on the slip reduction speed is performed by the control flow as described above. In addition, if there is a pedal operation by the driver during this speed control, it is always given priority.
[0022]
FIG. 3 shows a block diagram of the slip reduction speed estimation means (FIG. 1) according to one embodiment of the present invention. As shown in FIG. 3, the slip reduction speed is estimated from weather history information and map / calendar data. First, temperature history, precipitation history, humidity history, wind speed / wind direction history are used as weather history information. Also, data such as solar position / altitude, map data, tide level, etc. is obtained from the map / calendar data. Here, in addition to the latitude and longitude information of the road, the map data includes information such as the height of the building beside the road or the height of the mountain. The amount of solar radiation on the travel route, specifically, whether the travel route is shaded is calculated from these maps and calendar data. At the same time, it is calculated whether the coastal sand is likely to be scattered along the travel route. This will be described with reference to FIG. In this way, the road surface friction coefficient (μ) is estimated, and the slip reduction speed is calculated based on the estimated value.
[0023]
FIG. 4 shows a situation diagram in which road surface freezing is predicted by utilizing the weather history according to an embodiment of the present invention. FIG. 4 includes an area 401, a route 402, a sun 403, a mountain 404, a mountain shade 405, a section 406, and a host vehicle 407. 4 shows the weather history information of the region 401 and the solar radiation amount information of the section 406. The own vehicle is at the position shown in the figure at time t 0 and is traveling along the route 402. At this time, the weather history information is searched. Based on the precipitation history, we obtained data that it rained in the region 401 from just before midnight to after 3:00. The temperature history shows that the temperature has cooled down to near 0 ° C before sunrise. The section 406 shows data indicating that the mountain 404 is shaded from sunrise to nearly 11:00, and the amount of solar radiation cannot be obtained near time t0. From these data, road surface freezing is predicted with high probability in section 406 at time t0. In addition, if the amount of moisture per unit time permeated on the road 402 to some extent is added to the parameters for road surface freezing prediction at this time, the amount of water on the road surface when the temperature drops can be predicted to some extent. Therefore, the road surface freezing prediction accuracy is improved, which is more effective.
[0024]
FIG. 5 shows a time chart of the vehicle speed control when road surface freezing is predicted based on the weather history according to an embodiment of the present invention. FIG. 5 shows a region 401, a route 402, a sun 403, a mountain 404, a mountain shade 405, a section 406, a host vehicle 407, a succeeding vehicle 408, a point 409 at a time t1, a point 410 at a time t2, and a time t3. 411, a point 412 at time t4, a point 413 at time t5, and a point 414 at time t6. Here, as in FIG. 4, an example in which freezing is predicted in the section 406 will be described. The own vehicle is traveling on the route 402 at about 60 km / h. In the position of 407 in the figure, the slip reduction speed is estimated to be 15 km / h by freezing estimation in the section 406, and the speed control is to be performed. However, since the succeeding vehicle 408 follows at a predetermined inter-vehicle distance, To implement deceleration control. First, the vehicle decelerates from 60 km / h to 40 km / h in a section from point 409 to 410. The deceleration of about 20km / h reduces the opening of the relative speed with the following vehicle, reducing the probability of a rear-end collision. Thereafter, the section from point 410 to 411 travels at a constant speed of 40 km / h. In the section from point 411 to 412, the speed is reduced from 40 km / h to 15 km / h, which is the slip reduction speed in this case. The section from 412 to 413 including the section 406 travels at a constant speed of 15 km / h and passes through the section 406. The section from point 413 to 414 accelerates again and finally reaches 60 km / h. By performing deceleration control stepwise in this way, the opening of the relative speed with the following vehicle can be reduced, and the probability of a rear-end collision can be reduced. The deceleration pattern is changed at any time according to the inter-vehicle distance with the following vehicle, the own vehicle speed, the estimated slip reduction speed, and the distance to the point where the slip reduction speed is necessary. Further, deceleration is not limited to two stages, and a deceleration pattern of three or more stages may be selected. Further, as described in the explanation of FIG. 1, the following control may notify the subsequent vehicle of the deceleration of the host vehicle. This can further reduce the probability of a rear-end collision.
[0025]
FIG. 6 shows a comparative example of a speed control time chart when such a deceleration pattern is not taken. The driving environment is the same as in FIG. First, the deceleration pattern 601 decelerates from 60 km / h to 15 km / h which is the slip reduction speed in a section from the vicinity of the point 411 (time t3 ′) to the point 412 (time t4). In such a deceleration pattern, there is a possibility that the relative speed may open up to 45 km / h. Therefore, the possibility of a rear-end collision is not completely zero when following a following vehicle. This is because the following vehicle does not always predict freezing of the section 406 in the same manner as the own vehicle, and the deceleration of the own vehicle cannot be predicted in advance. In addition, when there is no pedestrian, bicycle, signal, etc. on a wide road with good visibility, the driver of the succeeding vehicle may assume that his / her vehicle cannot decelerate and stop, which may cause an alarm. In such a case, if the host vehicle decelerates as in the pattern 601, the following vehicle will be surprised, causing a brake pedal operation delay or a pedal operation error, and there is no possibility of a rear-end collision. I can't say that. Further, in the deceleration pattern 602, in the section from the vicinity of the point 409 (time t1 ′) to the point 412 (time t4), the vehicle decelerates from 60 km / h to the slip reduction speed of 15 km / h due to the slow deceleration. In the case of such a deceleration pattern, compared with the pattern 601, since the deceleration is slow, the probability of a rear-end collision with the following vehicle is low. However, in this case, the deceleration period becomes longer than the time (t 4 -t 1 ′) and the pattern 601. In such a case, there is a possibility that the driver of the following vehicle may mistakenly think that the own vehicle will stop and pass the own vehicle. In that case, it cannot be said that there is no possibility that the vehicle is involved due to a driving mistake or the like when the vehicle is overtaken. Even if the vehicle is overtaken safely, the following vehicle may enter the section 406 at a speed equal to or higher than the slip reduction speed, causing a slip. As described above, this is not a preferable deceleration pattern for the following vehicle itself and the own vehicle. In this regard, since the deceleration pattern shown in FIG. 5 is short in one deceleration period, it is unlikely that the driver of the following vehicle will stop the vehicle, and the possibility of overtaking is low. Moreover, since there is little opening of the relative speed, there is little possibility of falling into a dangerous state even if surprised, and this is considered to be a safer deceleration pattern.
[0026]
FIG. 7 shows a situation diagram in which coastal sand scattering / deposition is predicted by utilizing the weather history according to an embodiment of the present invention. FIG. 7 includes an area 701, a route 702, a host vehicle 703, buildings 704 a to e, a sea 705, a sandy beach 706, and a section 707. Moreover, the weather history information of the area 701 and the map information of the section AB are shown at the bottom of FIG. The own vehicle is at the position shown in the figure at time t0 and is traveling along the route 702. At this time, the weather history information is searched. Based on the precipitation history, we obtained data that a small amount of rain fell in the area 701 around 4 am. Moreover, the data that the strong wind blew from the sea direction from 9:00 am to 12:00 after the wind speed / wind direction history was obtained. In addition, we obtained data that the tide level was just before and after the low tide during the time when the strong winds were blowing. In section 707, data was obtained that the distance to the coast was short and that there were no buildings. That is, it shows that the section 707 faces the coast. From these data, in the section 707 at time t0, scattering / deposition of coastal sand on the road surface is predicted with high probability. In this way, it is possible to predict a decrease in the friction coefficient of the road surface due to scattering and accumulation of coastal sand using weather history information even in the case of traffic near the coast. As in the case of road surface freezing, the slip reduction speed is estimated, and speed control according to the situation of the following vehicle can be realized.
[0027]
FIG. 8 shows a speed control time chart when there is a failure ahead of the route according to an embodiment of the present invention. This embodiment can cope not only with speed control based on prediction of the road surface friction coefficient but also when a traffic obstacle such as an accident occurs. FIG. 8 shows route 801, own vehicle 802, succeeding vehicle 803, point 804 at time t1, point 805 at time t2, point 806 at time t3, point 807 at time t4, point 808 at time t5, time It consists of a point 809 at t6 and a failure occurrence point 810. The own vehicle is traveling on the route 801 at about 60 km / h. When the traffic obstacle information of the point 810 is obtained by some means at the position 802 in the figure, the deceleration control is finally performed step by step up to the slow speed. First, in the section from point 804 to 805, the vehicle decelerates from 60 km / h to 40 km / h. The deceleration of about 20km / h reduces the opening of the relative speed with the following vehicle, reducing the probability of a rear-end collision. This is the same as in the case of FIG. Thereafter, the section from point 805 to 806 travels at a constant speed of 40 km / h. In the section from 806 to 807, the vehicle decelerates from 40 km / h to 15 km / h. In the section from 807 to 808, the vehicle travels at a constant speed of 15 km / h. In the section from point 808 to 809, the vehicle decelerates from 15 km / h to the slow speed. In this way, since the vehicle has decelerated to the slow speed before reaching the point 810, even if it must be stopped due to the above-mentioned traffic obstacle, it can be stopped immediately.
[0028]
FIG. 9 shows a time chart when speed control and independent wheel braking force addition control (hereinafter referred to as VDC) or four wheel drive control (hereinafter referred to as 4WD) are used in combination according to an embodiment of the present invention. The speed time chart is the same as in FIG. In the present embodiment, VDC or 4WD is ON near time t3. By using in combination with these controls, a further slip reduction effect can be expected. Note that 4WD may not be changed mechanically during traveling, and in that case, the driver may only be notified of the change to 4WD.
[0029]
Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the function. For example, when the low μ information is obtained from the weather history information, the low μ information may be notified to the driver of the vehicle by voice or display before the calculation of the slip reduction speed.
[0030]
In addition, this invention is not limited to the structure of said each embodiment, As long as it is in the range of this invention, it is good also as a structure which combined a part of said embodiment.
[0031]
【The invention's effect】
According to the present invention, when it is predicted that the road friction coefficient is low due to freezing of the road ahead, accumulation of coastal sand, etc., the speed at which the probability of slipping can be reduced while reducing the possibility of a rear-end collision from the following vehicle. Thus, it is possible to provide an automobile travel control device that can be controlled more safely and that has improved safety.
[Brief description of the drawings]
FIG. 1 shows an overall configuration of driving control of an automobile according to an embodiment of the present invention.
FIG. 2 shows a control flowchart according to an embodiment of the present invention.
FIG. 3 shows a block diagram of slip reduction speed estimation, according to one embodiment of the present invention.
FIG. 4 shows a situation diagram in which road surface freezing is predicted by utilizing weather history according to an embodiment of the present invention.
FIG. 5 is a time chart of own vehicle speed control when road surface freezing is predicted based on weather history according to an embodiment of the present invention.
FIG. 6 shows a comparative example of a speed control time chart.
FIG. 7 shows a situation diagram in which coastal sand scattering / deposition is predicted by utilizing weather history according to an embodiment of the present invention.
FIG. 8 shows a speed control time chart when there is a failure ahead in the route according to an embodiment of the present invention.
FIG. 9 is a time chart when speed control and VDC or 4WD control are used in combination according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Slip reduction speed estimation means, 2 ... Route estimation means, 3 ... Speed command value calculation means, 4 ... Speed control means, 5 ... Notification control means, 6 ... Engine throttle, 7 ... Transmission, 8 ... Brake, 9 ... Subsequent vehicle notification device.

Claims

Subsequent vehicle information input means for inputting an inter-vehicle distance from the subsequent vehicle by a sensor,
A slip reduction speed estimating means for obtaining a road surface friction coefficient of a route to be traveled in the future and obtaining a slip reduction speed at a predetermined point of the route based on the road surface friction coefficient;
The slip reduction speed obtained by the slip reduction speed estimation means, the distance between the current point of the own vehicle and the predetermined point, the current speed of the own vehicle, and the subsequent vehicle obtained by the subsequent vehicle information input means Speed command value calculating means for obtaining a speed command value pattern that gradually decelerates based on the inter-vehicle distance;
Speed control means for controlling the speed of the vehicle according to the speed command value pattern obtained by the speed command value calculation means;
The rear of your vehicle has a warning light for the following vehicle,
In addition to speed control based on the slip reduction speed, a travel control device that intermittently activates the notification lamp until reaching a section that requires traveling at a speed equal to or less than the slip reduction speed.

Subsequent vehicle information input means for inputting an inter-vehicle distance from the subsequent vehicle by a sensor,
A slip reduction speed estimating means for obtaining a road surface friction coefficient of a route to be traveled in the future and obtaining a slip reduction speed at a predetermined point of the route based on the road surface friction coefficient;
The slip reduction speed obtained by the slip reduction speed estimation means, the distance between the current point of the own vehicle and the predetermined point, the current speed of the own vehicle, and the subsequent vehicle obtained by the subsequent vehicle information input means Speed command value calculating means for obtaining a speed command value pattern that gradually decelerates based on the inter-vehicle distance;
Speed control means for controlling the speed of the vehicle according to the speed command value pattern obtained by the speed command value calculation means;
Independent wheel braking force adding means automatic selection means for automatically selecting function operation-function non-operation of independent wheel braking force adding means for independently applying braking force to wheels according to traveling environment information and steering rudder angle,
In addition to the speed control based on the slip reduction speed, the independent wheel braking force adding means is automatically operated by the independent wheel braking force adding means automatic selection means until the vehicle reaches a section where traveling at a speed lower than the slip reduction speed is required. A traveling control device that functions in a functional manner.

Subsequent vehicle information input means for inputting an inter-vehicle distance from the subsequent vehicle by a sensor,
A slip reduction speed estimating means for obtaining a road surface friction coefficient of a route to be traveled in the future and obtaining a slip reduction speed at a predetermined point of the route based on the road surface friction coefficient;
The slip reduction speed obtained by the slip reduction speed estimation means, the distance between the current point of the own vehicle and the predetermined point, the current speed of the own vehicle, and the subsequent vehicle obtained by the subsequent vehicle information input means Speed command value calculating means for obtaining a speed command value pattern that gradually decelerates based on the inter-vehicle distance;
Speed control means for controlling the speed of the vehicle according to the speed command value pattern obtained by the speed command value calculation means;
Provided with driving wheel automatic selection means for automatically selecting the number of driving wheels of the vehicle based on the traveling environment information,
In addition to the speed control based on the slip reduction speed, a travel control device that automatically changes the driving wheels of the host vehicle to four-wheel drive before reaching a section that requires traveling at a speed equal to or less than the slip reduction speed. .

Said speed control means in accordance with the deceleration pattern which has been determined by the speed command value calculating means, the engine throttle, the transmission, to control the speed of the vehicle using at least one of the brake, according to claim 1 to 3 The travel control device according to any one of the above.

The slip reduction speed estimation means predicts a route to be traveled in the future based on the input map information and the vehicle position information, obtains a road surface friction coefficient of the route, and determines a predetermined point on the route based on the road surface friction coefficient. The travel control device according to claim 1, wherein a slip reduction speed is obtained .

The slip reduction speed estimation means predicts a route to be traveled in the future based on a change in the current position information of the own vehicle, obtains a road surface friction coefficient of the route, and slips at a predetermined point on the route based on the road surface friction coefficient The travel control apparatus according to any one of claims 1 to 3, wherein a reduction speed is obtained .

The slip reduction speed estimation means obtains a road surface friction coefficient of a route set in advance by a driver, and obtains a slip reduction speed at a predetermined point of the route based on the road surface friction coefficient. The travel control device described.

The slip reduction speed estimation means obtains a road surface friction coefficient of a route to be traveled in the future based on weather history information of an area including the route, and obtains a slip reduction speed in the route based on the road surface friction coefficient. The travel control device according to any one of 3 to 3.

The slip reduction speed estimation means obtains a road surface friction coefficient of a route to be traveled in the future, obtains a slip reduction speed at a predetermined point on the route based on the road surface friction coefficient, and determines the slip reduction speed from a legal speed of the route. 4 is set as the slip reduction speed, the travel control device according to any one of claims 1 to 3.

The speed command value calculation means is configured to input the slip reduction speed obtained by the slip reduction speed estimation means, a distance between the current position of the own vehicle and the predetermined position, the current speed of the own vehicle, and the subsequent vehicle information. A speed command value pattern for gradually decelerating is obtained based on the following vehicle information obtained by the means, and a speed command value based on the deceleration of the preceding vehicle or a sharp curve of the travel path and a speed command based on the speed command value pattern The travel control device according to any one of claims 1 to 3 , wherein a lower speed command value is output among the values .

The travel control device according to any one of claims 1 to 3 , wherein when a driver's pedal operation is performed during control by the speed control means, priority is given to speed control by the pedal operation .

The speed command value calculation means includes the slip reduction speed obtained by the slip reduction speed estimation means, the distance between the current position of the own vehicle and the predetermined point, the current speed of the own vehicle, and the subsequent vehicle information input means. And at least one transition speed smaller than the current speed of the own vehicle and larger than the slip reduction speed is set based on the following vehicle information obtained in step S1, and the current speed of the own vehicle, the transient speed, and the slip reduction are set. The travel control device according to any one of claims 1 to 3, wherein a speed pattern that decelerates stepwise in order of speed is obtained .

The travel control device according to any one of claims 1 to 3, further comprising notification control means for notifying a subsequent vehicle of deceleration of the own vehicle based on the speed command value calculated by the speed command value calculation means .