JP4010247B2 - Parking assistance device - Google Patents

Description

で表される。
【００１６】
ここで、式（１）及び（２）を三角関数の公式を用いて、変形すると、
tan（α／２＋β／２）＝JOx／JOy
sin^２（α／２−β／２）＝（JOx^２＋JOy^２）／（１６Rc^２）
となり、α、βを、既知のリヤアクスル中心ＪＯの座標（ＪＯｘ，ＪＯｙ）を用いて算出することができる。
リヤアクスル中心ＪＯの座標（ＪＯｘ，ＪＯｙ）は、車両１０を車両２０の後方に無理のない操作で駐車できる標準的な値として、例えば、ＪＯｘ＝２．３ｍ、ＪＯｙ＝４．５ｍの値が設定されている。
リヤアクスル中心ＪＯの標準的な座標ＪＯｘおよびＪＯｙは、車両１０の車格、操舵特性などに応じて値を設定することが望ましい。
【００１７】
次に、実施の形態１に係る駐車支援装置の縦列駐車時の動作について説明する。
まず、図３に示されるように、道路と平行に、すなわち目標とする駐車枠Ｔに平行に車両１０を直進前進させて、運転者の位置ＤＲのＹ座標が駐車中の車両２０の後端２０ａのＹ座標に一致し、車両１０が車両２０に対して車両間隔ｄ、例えば５０ｃｍとなるような車両位置Ｊ１へと向かう。このとき、前進しながら、車両の前端側部に設置されている超音波センサ７により車両側方の障害物、例えば駐車中の車両２０までの距離が、初期停止位置と駐車枠との位置関係を表すものとして、連続して測定される。車両１０は次第に車両位置Ｊ１に接近し、図４に示されるように、運転者の位置ＤＲのＹ座標が駐車中の車両２０の後端２０ａのＹ座標に一致する位置にまで至る。
【００１８】
ここで、車両１０の前進に伴って、超音波センサ７の位置に対応した障害物までの測定距離ｘは図５のように示される。目標となる駐車枠Ｔには車両が存在しないので、この駐車枠Ｔの側方を通るときには測定距離ｘは非常に大きな値となるが、図３に示されるように超音波センサ７のＹ座標が駐車中の車両２０の後端２０ａのＹ座標に一致する座標ｙ１に到達すると、測定距離ｘは急激に小さくなって超音波センサ７から車両２０までの距離となる。このときの測定距離ｘは、初期停止の基準位置ＳＴである車両２０からの間隔５０ｃｍとｘ方向のズレｄｘ１との和で表される。
【００１９】
このようにして、超音波センサ７の測定距離ｘの急激な変化から、コントローラ１は図３に実線で示されるように車両１０における超音波センサ７が座標ｙ１に到達したことを認識することができる。
【００２０】
また、超音波センサ７は加速度センサ９による加速度の測定開始タイミングを決定する開始決定手段としても機能する。すなわち、超音波センサ７の測定結果の急激な変化より、図３に示されるようにＹ座標方向に関し車両１０の前端が駐車中の車両２０の後端２０ａと揃った位置が特定され、そこから加速度センサ９による加速度の測定が開始される。加速度センサ９は例えば図６に実線で示されるような加速度に関する出力値をコントローラ１へと出力する。コントローラ１は、その加速度に関する出力値を時間積分して速度を求める。具体的には、コントローラ１内の算出部１ａにおいて、Ｖｔ＝Ｋｖ・ΣＥｔで示される計算式を用いて車両の速度を算出する。ここで、Ｅｔは、本実施の形態では２０ｍｓ毎の加速度に関する出力値であり、Ｋｖは、速度算出用の係数であり、Ｖｔは車両の速度である。これにより、図６に一点鎖線で示されるような車両の速度が得られる。さらに、コントローラ１は、求めた速度を時間積分して距離を求める。具体的にはＤｔ＝Ｋｄ・ΣＶｔで示される計算式を用いて車両の速度を算出する。ここで、Ｖｔは、本実施の形態では２０ｍｓ毎の速度の算出値であり、Ｋｄは、距離算出用の係数であり、Ｄｔは車両の算出移動距離である。これにより、図６に二点鎖線で示されるような車両の算出移動距離が得られる。
このようにして、コントローラ１においては、加速度センサ９によって測定された加速度を二階積分することによって、超音波センサ７の出力結果により決定される測定開始タイミングの車両位置からの車両の算出移動距離が算出されている。
【００２１】
そこで、コントローラ１は、車両１０の前端から運転者の位置ＤＲまでの長さＬＤを予め記憶しておくと共に上述したように二階積分によって得られている車両１０の算出移動距離を監視し、超音波センサ７が座標ｙ１に達したときから車両１０が距離ＬＤだけ前進したところでスピーカ６を介して運転者に特定の停止音を発する。この停止音を聞いた運転者は車両１０を停止させる。その結果、運転者の位置ＤＲのＹ座標が駐車中の車両２０の後端２０ａのＹ座標に一致する位置となり、ここを初期停止位置とする。このときの超音波センサ７による測定距離ｘは、初期停止の基準位置ＳＴである車両２０からの間隔５０ｃｍとｘ方向のズレｄｘ２との和で表される。
【００２２】
車両１０を正確に初期停止の基準位置ＳＴに位置させることは困難であるため、上記のようなｘ方向のズレｄｘ１及びｄｘ２が生じやすくなる。なお、ズレｄｘ１とズレｄｘ２は、車両１０が駐車中の車両２０に対して平行に走行していれば互いに等しくなるが、ある傾きをもって斜めに走行している場合には互いに異なった値となる。座標ｙ１とｙ２との間の距離は予めコントローラ１に記憶されているＬＤであるので、ズレｄｘ１及びｄｘ２と距離ＬＤから、この初期停止位置における車両１０の初期停止の基準位置ＳＴに対する傾きをも求めることができる。
そこで、初期停止位置に停止した状態で運転者が縦列モードスイッチ４を作動させると、コントローラ１は、このようにして測定されたズレｄｘ１及びｄｘ２およびリヤアクスル中心ＪＯの標準的な座標ＪＯｘおよびＪＯｙから、実際の初期停止位置のリヤアクスル中心ＪＯ’の座標（ＪＯｘ＋ｄｘ，ＪＯｙ＋ｄｙ）を得て適正に駐車枠Ｔに縦列駐車することができるように上記の旋回角度α，β及びδを算出する。
【００２３】
また、縦列モードスイッチ４の作動に基づいてコントローラ１は、初期停止位置を車両のヨー角が０度の位置として設定すると共に縦列駐車のためのプログラムを起動させる。運転者は、車両１０のハンドルを右側最大に操舵してフル切り状態にし、そのまま車両１０を前進させる。コントローラ１は、ヨーレートセンサ２から入力される車両１０の角速度から車両のヨー角を算出して、このヨー角と算出された旋回角度βの値とを比較する。車両１０が、初期停止位置から後退開始位置である車両位置Ｋ１に近づくにつれて、コントローラ１は、ヨー角と算出された旋回角度βとの差を基に、車両位置Ｋ１に接近したことを知らせる接近情報と、車両位置Ｋ１に到達したことを知らせる到達情報とをスピーカ６を介して運転者に知らせる。
例えば、接近情報として、スピーカ６から「ピッ、ピッ」という間欠音が発せられ、この間欠音及び点滅の周期は、ヨー角と旋回角度βとの差が少なくなると共に短くなる。ヨー角と旋回角度βとの差がなくなると、到達情報として、スピーカ６から「ピー」という連続音が発せられる。
【００２４】
運転者は、到達情報に従って車両１０を車両位置Ｋ１に停止させる。次に、運転者は、ハンドルを左にいっぱい操舵してフル切り状態にし、そのまま車両１０を後退させる。コントローラ１は、車両のヨー角と算出された旋回角度α（＝β＋δ）の値とを比較する。車両１０が、車両位置Ｋ１から切り返し位置となる車両位置Ｌ１に近づくにつれて、すなわち、車両のヨー角が算出された旋回角度αの値に近づくにつれて、コントローラ１は、ヨー角と算出された旋回角度αとの差を基に、車両位置Ｌ１に接近したことを知らせる接近情報と、車両位置Ｌ１に到達したことを知らせる到達情報とをスピーカ６を介して運転者に知らせる。
【００２５】
運転者は、到達情報に従って車両１０を車両位置Ｌ１に停止させる。次に、運転者は、車両位置Ｌ１でハンドルを反対方向に切り返して、右側最大に操舵してフル切り状態にし、そのまま車両１０を後退させる。コントローラ１は、車両１０のヨー角が０度に近づくにつれて、車両１０が目標となる駐車枠Ｔ内の車両位置Ｍ１に接近したことを知らせる接近情報と、車両位置Ｍ１に到達したことを知らせる到達情報とをスピーカ６を介して運転者に知らせる。これにより、運転者は、車両位置Ｍ１で車両１０を停止させ、駐車を完了することができる。
【００２６】
このように駐車支援を行うに際して、加速度センサによる測定値から車両の算出移動距離を獲得しているため、高精度の車輪速センサを必要とすることなく、精度の高い車両位置の特定が可能であり、正確な初期停止位置の把握が可能となっている。また、加速度センサの設置態様は、車輪速センサの設置態様とは異なり、コントローラを収めている駐車支援装置の筐体内に一緒に収納させることが可能であり、車両の改造なしに実施することができ、コスト面でも安価である。
【００２７】
また、本実施の形態では、コントローラ１は、上述したように加速度センサ９の測定結果を二階積分して得られる車両の算出移動距離と、車輪速センサ８の出力パルスから得られる車両の実測移動距離とを比較して、それ以降の算出移動距離の算出式を補正する補正部１ｂを備える。すなわち、図６に示されるように、車輪速センサ８における１パルスの立ち上がりから次の１パルスの立ち上がりまでのパルス間進行距離ＬＡは、前述した車輪速センサ８における分解能である約４０ｃｍに等しい。一方、上記の１パルスの立ち上がりから次の１パルスの立ち上がりまでの時間に関して算出した算出移動距離ＬＢも約４０ｃｍに等しくなるはずである。しかしながら、実際には、経時変化や温度特性によるセンサ特性の変化、積分時に採用していた算出用の係数Ｋｖ，Ｋｄの影響などにより、算出移動距離と実測移動距離とが大きく相違することがあり得る。そこで、本実施の形態では、コントローラ１内の補正部１ｂにおいて、算出移動距離と実測移動距離とを比較して、その結果に基づいて随時、算出用の係数をより適切な値へと補正していく。よって、センサ特性が変化した場合にも精度の高い距離計測が可能となり、ひいては精度の高い駐車案内を行うことができる。また、かかる補正は、１パルス分又は複数パルス分毎に比較を行いその都度補正を行う仕方でもよいし、１パルス分又は複数パルス分毎に比較を行い複数回の比較結果をもとに平均化して補正する仕方でもよい。
【００２８】
実施の形態２．
実施の形態２に係る駐車支援装置は、図１に示した実施の形態１の駐車支援装置と同様の構成を有しているが、図７に示されるように、目標となる駐車枠Ｔの前方に車両２０が既に駐車しているだけでなく、後方にも車両３０が駐車している場合に有効なものである。
まず、駐車枠Ｔの後方に駐車している車両３０の側方から道路と平行に車両１０を直進前進させつつ、超音波センサ７により車両側方の障害物までの距離測定を連続して行う。この超音波センサ７による距離測定は、車両１０が初期停止位置に至るまで、すなわち運転者の位置ＤＲのＹ座標が駐車中の車両２０の後端２０ａのＹ座標に一致する位置に至るまで連続して行われる。
【００２９】
このとき、車両１０の前進に伴って、超音波センサ７で測定される距離ｘは図８のように示される。初めは、駐車枠Ｔの後方に駐車している車両３０までの距離が測定されるが、超音波センサ７のＹ座標が駐車中の車両３０の前端３０ａのＹ座標に一致する座標ｙ０に到達した後は車両が存在しないので、測定距離ｘは非常に大きな値となる。さらに、超音波センサ７のＹ座標が駐車枠Ｔの前方に駐車している車両２０の後端２０ａのＹ座標に一致する座標ｙ１に到達すると、測定距離ｘは急激に小さくなって超音波センサ７から車両２０までの距離となる。従って、測定距離ｘの急激な変化から、コントローラ１は超音波センサ７が座標ｙｏ及びｙ１に到達したことを認識することができ、この間に車両１０が移動した距離ＰＳＬを、実施の形態１と同様に加速度センサ９により測定された加速度の二階積分により算出することができる。この距離ＰＳＬは、駐車中の車両３０と２０に形成された駐車スペースの長さを表している。
【００３０】
超音波センサ７が座標ｙ１に到達した後は、実施の形態１と同様に、車両１０が距離ＬＤだけ前進して超音波センサ７が座標ｙ２に達したところでスピーカ６を介して運転者に特定の停止音を発する。この停止音を聞いた運転者は車両１０を停止させる。その結果、運転者の位置ＤＲのＹ座標が駐車中の車両２０の後端２０ａのＹ座標に一致する位置となり、ここを初期停止位置とする。
そして、初期停止位置に停止した状態で運転者が縦列モードスイッチ４を作動させると、コントローラ１は、測定されたズレｄｘ１及びｄｘ２と駐車スペースの長さＰＳＬに基づいて、実際の初期停止位置から適正に駐車枠Ｔに縦列駐車することができるように旋回角度α，β及びδを算出する。
このようにして算出された旋回角度α，β及びδに基づいて、コントローラ１は実施の形態１と同様に、フル切り状態での一旦停止の適正なタイミングをスピーカ６を介して運転者に提供し、これにより運転者は駐車枠Ｔへの縦列駐車を完了することができる。
【００３１】
実施の形態３．
実施の形態３に係る駐車支援装置は、図１に示した実施の形態１の駐車支援装置と同様の構成を有しているが、予め設定された初期停止の基準位置に車両を停止させるのではなく、超音波センサ７により測定された車両側方の障害物までの距離ｘに基づいてコントローラ１が適切な初期停止位置を演算して運転者に案内するものである。さらに、初期停止位置から操舵角を最大にして車両を後退させて切り返し位置で停止させ、切り返し位置から操舵角を逆方向に最大にして車両を後退させて目標とする駐車スペースに至るような案内情報が運転者に提供される。
【００３２】
図９を参照して適切な初期停止位置の演算方法を説明する。車両１０と駐車中の車両２０との間の車間距離をＢとする。これらの車両の幅をそれぞれＷ２とすると、駐車操作により車両１０をＸ方向に移動させるべき距離ＤＸは、
DX＝B＋W2
と表される。車両１０のリヤアクスル中心が初期停止位置Ｐ１におけるＰ０から切り返し位置Ｑ１におけるＱ０まで移動するときの旋回角度をγとし、リヤアクスル中心の最小旋回半径をＲｃとすると、
DX＝２Rc・(1−cosγ)
となる。
ここで、距離ＤＸは超音波センサ７により測定することができ、最小旋回半径Ｒｃは既知であるので、上式から旋回角度γを算出することができる。
旋回角度γが求められると、
DY＝２Rc・sinγ
よりリヤアクスル中心の位置Ｐ０とＲ０との間のＹ方向の距離ＤＹを求めることができる。
【００３３】
車両１０の旋回の際における駐車中の車両２０の右後端Ｚと車両１０の左前端との間の干渉余裕をＦとする。なお、図９では、両者が互いに干渉しているので、Ｆは負の値となる。
車両１０の左前端の旋回半径Ｒｆｌは車両１０の全長をＬとして、
Rfl＝{(Rc＋W2/2)^２＋(L−a2)^２}^１／２
と表される。一方、車両２０の右後端Ｚと車両１０の旋回中心Ｃ７との間の距離ＺＣ７は、車両２０の右後端Ｚと車両１０の旋回中心Ｃ７との間のＹ方向の距離Ｅを用いて、
ZC7＝{(Rc−W2/2)^２＋E^２}^１／２
となる。
【００３４】
干渉余裕Ｆは、
F＝ZC7−Rfl
と表されるので、このＦに具体的な数値、例えば４０ｃｍを代入することにより、距離Ｅの値を定めることができる。
ここで、既に距離ＤＹが求められているため、駐車中の車両２０の後端から初期停止位置Ｐ１の車両１０の前端までの前方距離Ｄは、
D＝DY−E＋L−a2
となる。このようにして、前方距離Ｄを車両１０と駐車中の車両２０との間の車間距離Ｂから求めることができる。
【００３５】
次に、実施の形態３に係る駐車支援装置の縦列駐車時の動作について説明する。
まず、道路と平行に車両１０を直進前進させて駐車スペースの側方を通過中に縦列モードスイッチ４を作動させる。これにより、車両１０の前端側部に設置されている超音波センサ７によって駐車中の車両２０までの距離の測定が連続して行われ、実施の形態１と同様にしてコントローラ１は、超音波センサ７が車両２０の後端位置に到達したことを認識すると共に車両１０と車両２０との間の車間距離Ｂを測定し、上記の手順に従って、車両２０の後端から適切な初期停止位置Ｐ１の前端までの前方距離Ｄとその後の旋回角度γとを確定することができる。
【００３６】
コントローラ１は、実施の形態１と同様に加速度センサ９により測定された加速度を二階積分することにより車両１０の移動距離を算出し、この移動距離を監視して、超音波センサ７が駐車中の車両２０の後端位置に達したときから車両１０が前方距離Ｄだけ前進したところでスピーカ６を介して運転者に特定の停止音を発する。この停止音を聞いた運転者は車両１０を停止させる。その結果、車両１０は適切な初期停止位置Ｐ１に停止することとなる。このとき、コントローラ１は、ヨーレートセンサ２による車両１０のヨー角をリセットする。
【００３７】
その後、運転者は、車両１０のハンドルを左側最大に操舵してフル切り状態にし、そのまま車両１０を後退させる。コントローラ１は、車両のヨー角と確定された旋回角度γの値とを比較し、ヨー角が旋回角度γに接近するとスピーカ６を介して接近情報を出力し、さらにヨー角が旋回角度γになったところで切り返し位置Ｑ１に到達したと判断してスピーカ６を介して到達情報を出力する。
運転者は、到達情報に従って車両１０を切り返し位置Ｑ１に停止させ、ここでハンドルを反対方向に切り返して、右側最大に操舵してフル切り状態にし、そのまま車両１０を後退させる。コントローラ１は、車両１０のヨー角が０度に近づくにつれて、車両１０が目標となる駐車スペース内の車両位置Ｒ１に接近したことを知らせる接近情報と、車両位置Ｒ１に到達したことを知らせる到達情報とをスピーカ６を介して運転者に知らせる。これにより、運転者は、車両位置Ｒ１で車両１０を停止させ、駐車を完了することができる。
【００３８】
なお、駐車中の車両２０の後端から適切な初期停止位置Ｐ１の前端までの距離Ｄとその後の旋回角度γの車間距離Ｂに対する関係は、車両１０の特性に基づいて例えば図１０に示されるように確定される。
この実施の形態３においても、実施の形態２と同様に、初期停止位置に向かう直進前進の際に目標となる駐車スペースの長さを計測して駐車の可否を案内したり、後方に駐車中の車両等の障害物との干渉を警報したりすることができる。
【００３９】
実施の形態４．
この実施の形態４は、実施の形態３において、初期停止位置に向かう直進前進の方向が駐車中の車両２０と平行でなく傾き角度εを有する場合に有用なものである。図１０に示されるように、角度εだけ傾いて停止した車両１０の位置Ｐ２は、駐車中の車両２０と平行に停止した位置Ｐ１から駐車操作により角度εだけ後退した状態と考えることができる。
【００４０】
位置Ｐ１の車両１０が旋回半径Ｒｃで角度εだけ後退して位置Ｐ２に至るとすると、位置Ｐ２における車両１０の左前端の座標（Ｘ１ｆ、Ｙ１ｆ）は、旋回中心を原点として位置Ｐ１における車両１０の左前端の座標（Ｘ０ｆ、Ｙ０ｆ）を用いて、
X1f＝X0f・cosε＋Y0f・sinε
Y1f＝Y0f・cosε−X0f・sinε
と表される。従って、
位置Ｐ１とＰ２との間の車両１０の左前端のＸ方向変位ΔＸ１ｆは、
ΔX1f＝X1f−X0f＝Y0f・sinε−X0f・(1−cosε)
となり、実際の車両１０のパラメータで表現すると、
ΔX1f＝(L−a2)・sinε−(Rc−W2/2)・(1−cosε)
となる。
【００４１】
実際の車両１０では、例えば図１２に示されるように、車両１０の前端側部に設置されている超音波センサ７で駐車中の車両２０の後端を検出したときの水平距離をＡ０とすると、この距離Ａ０に対応する車両２０に平行な車両の水平距離Ｂ０は、
B0＝A0−ΔX1f＝A0−(L・a2)・sinε＋(Rc−W2/2)・(1−cosε)
となる。
【００４２】
ところで、傾き角度εは、例えば図１３に示されるように、超音波センサ７で駐車中の車両２０の後端を検出してからＨ１だけ進んだときの車両２０との車間距離Ａ１と、さらにＨ２だけ進んだときの車両２０との車間距離Ａ２から、
ε＝tan^−１{(A2−A1)/H2}
で得られる。
【００４３】
次に、図１４に示されるように、車間距離Ｂに対する前方距離Ｄと旋回角度γの関係を示すグラフにおいて、前方距離Ｄが０のときの車間距離Ｂ０の点から延びる傾きεの直線と前方距離Ｄを表す曲線との交点により、駐車中の車両２０と平行な車両に置き換えたときの適切な前方距離Ｄａを求めることができる。さらに、傾きεの直線と前方距離Ｄを表す曲線との交点からＹ軸に平行に引いた直線と旋回角度γを表す曲線との交点により、適切な旋回角度γａを求めることができる。
【００４４】
図１１において、位置Ｐ１とＰ２との間の車両１０の左前端のＹ方向変位ΔＹ１ｆは、
ΔY1f＝Y1f−Y0f＝−{X0f・sinε＋Y0f・(1−cosε)}
となり、実際の車両１０のパラメータで表現すると、
ΔY1f＝−{(Rc−W2/2)・sinε＋(L−a2)・(1−cosε)}
となる。
角度εだけ傾いた車両は、駐車中の車両２０と平行な車両より上記のＹ方向変位ΔＹ１ｆだけ手前に位置すると考えられるので、前方距離ＤａからＹ方向変位ΔＹ１ｆを差し引いた距離だけＹ方向に進めばよく、角度εの斜め方向には次の式で表される距離Ｄ１となる。

【００４５】
また、旋回角度γについては、駐車中の車両２０と平行な車両から既に角度εだけ旋回しているので、
γ1＝γa−ε
で表される角度γ１が角度εだけ傾いた初期停止位置から切り返し位置までの旋回角度となる。
なお、切り返し位置から目標となる駐車スペースまでの旋回角度はγａとなる。
【００４６】
そこで、実施の形態３において、初期停止位置に向かう直進前進の方向が駐車中の車両２０に対して角度εで傾いていると判定された場合には、コントローラ１は、実施の形態１と同様に加速度センサ９により測定された加速度を二階積分することにより算出した車両１０の移動距離を監視し、超音波センサ７が駐車中の車両２０の後端位置に達したときから車両１０が上記の距離Ｄ１だけ斜めに前進したところで停止し、その初期停止位置からハンドルを左側最大に操舵して角度γ１だけ後退したところで再び停止し、ハンドルを右側最大に切り返して角度γａだけ後退したところで駐車を完了するように運転者に案内情報を出力すればよい。
【００４７】
なお、この実施の形態４においても、実施の形態２と同様に、初期停止位置に向かう直進前進の際に目標となる駐車スペースの長さを計測して駐車の可否を案内したり、後方に駐車中の車両等の障害物との干渉を警報したりすることができる。
超音波センサ７による駐車中の車両２０との車間距離の測定は、実際には、車両の角の丸みの影響やセンサの特性に応じて補正を行うことが望ましい。
また、距離Ｄ１及び角度γ１を幾何学的に求める場合について説明したが、解析的に算出するようにしてもよい。
【００４８】
実施の形態５．
実施の形態５は、上述した実施の形態３及び４において、駐車スペースの側方を通過中に縦列モードスイッチ４を作動させることにより駐車中の車両２０までの距離の測定を開始する代わりに、超音波センサ７による車両側方の障害物までの距離の測定と加速度センサ９の測定結果に基づく移動距離の算出とを常時行って走行距離に応じた車両側方の障害物までの距離を履歴保存し、この履歴を利用して初期停止位置を算出しようとするものである。
【００４９】
コントローラ１は、超音波センサ７及び加速度センサ９を常時作動させ、これらのセンサから入力される信号に基づいて過去の所定時間分あるいは所定走行距離分における走行距離に応じた車両側方の障害物までの距離を履歴保存する。
駐車スペースの側方を通過して適当な位置、例えば実施の形態３及び４の初期停止位置のように駐車中の車両２０の側方で車両１０を停止させて縦列モードスイッチ４を作動させる。これにより、コントローラ１は、停止前の所定時間分あるいは所定走行距離分における走行距離に応じた車両側方の障害物までの距離の履歴に基づき、実施の形態３あるいは４に記載したような演算方法によって駐車スペースに縦列駐車するための適正な初期停止位置を算出する。
【００５０】
初期停止位置が算出されると、コントローラ１は直進前進あるいは直進後退して初期停止位置に至るようにスピーカ６を介して運転者に案内する。
ただし、コントローラ１に保存されている履歴だけでは初期停止位置を算出することができない場合には、さらに直進前進あるいは直進後退するようにスピーカ６を介して運転者に案内し、その間に得られた走行距離と障害物までの距離との関係を保存されている履歴に加味して初期停止位置の算出を行う。その後、コントローラ１は直進前進あるいは直進後退して初期停止位置に至るようにスピーカ６を介して運転者に案内する。
【００５１】
このようにして車両１０が初期停止位置に停止した後は、コントローラ１は、実施の形態３あるいは４と同様にして、車両１０が切り返し位置へ至り、さらに駐車スペースへ至るようにスピーカ６を介して案内情報を運転者に提供する。
なお、この実施の形態５においても、実施の形態２〜４と同様に、初期停止位置に向かう直進前進の際に目標となる駐車スペースの長さを計測して駐車の可否を案内したり、後方に駐車中の車両等の障害物との干渉を警報したりすることができる。
上述した実施の形態５によれば、適当な位置に車両１０を停止させて縦列モードスイッチ４を作動させるだけで、過去の履歴に基づき適正な初期停止位置が算出されるので、さらに操作性の優れた駐車支援装置が実現される。
【００５２】
実施の形態６．
実施の形態６に係る駐車支援装置の構成を図１５に示す。この実施の形態６の駐車支援装置は、図１に示した実施の形態１の装置において、超音波センサ７の代わりに光センサ１１を側方距離センサとして車両の前端側部に設置し、車両の側方の障害物までの距離を測定するものである。
このような実施の形態６によっても、実施の形態１〜５と同様に、フル切り状態での一旦停止の適正なタイミングをスピーカ６を介して運転者に提供し、駐車枠Ｔへの縦列駐車を完了させることができる。
なお、光センサ１１を用いても、実施の形態２と同様に、駐車スペースの長さを計測して旋回角度α，β及びδの算出に役立てることが可能である。
光センサ１１は、ＬＥＤやレーザダイオード等の発光手段とフォトトランジスタやＣＣＤデバイス等の受光手段との組み合わせから構成することができる。さらに、光センサ１１の代わりにレーダー等、光以外の電磁波を利用したセンサでもよい。
【００５３】
なお、上述した実施の形態１〜６において、コントローラ１による旋回角度の算出の際に、ズレが大きいために駐車運転に適用し得る旋回角度を算出することができない場合や、最大舵角に保持しつつその旋回角度で車両１０を旋回させると、縦列駐車時に車両１０が駐車中の車両２０等の障害物に干渉することが予測される場合は、スピーカ６を介して運転者に警報を発するように構成することもできる。このようにすれば、初期停止位置の位置ズレを考慮して算出された旋回角度に伴って障害物に干渉することを防止することができる。
【００５４】
また、実施の形態１〜６ではヨー角検出手段としてヨーレートセンサを用いたが、ヨー角を検出する手段は、ポジションジャイロを用いる方法や左右車輪にそれぞれ回転センサを装着しそれらの回転差からヨー角を検出する方法でもよく、さらに、地磁気センサやＧＰＳシステムを用いた方法でもよい。
なお、上記の実施の形態１〜６において、接近情報及び到達情報として、接近あるいは到達の目標となる車両位置ごとに、スピーカ６から発する音の音量及び音色を変えたり、内容の異なる音声を発するようにしてもよい。また、案内手段は、スピーカに限られるものではなく、ブザー、ＬＥＤ、ランプでもよく、ディスプレイ上に文字、マークを表示してもよい。さらに、ハンドル等を介して運転者に伝達される振動でもよい。
【００５５】
さらに、上記の実施の形態１〜４においては、超音波センサ７が加速度センサ９による加速度の測定開始タイミングを決定する開始決定手段として機能していたが、この態様に代えて、運転者による操作用のスイッチなどの入力手段、音声認識手段、画像認識手段、障害物との側方距離を測る超音波センサとは別の特定のセンサなどを採用することができる。
また、上記の実施の形態１〜４においては、前記初期停止位置と前記駐車枠との位置関係を認識する認識手段として、側方距離センサすなわち超音波センサ７を用いているが、本発明はこれに限定されるものではなく、画像認識手段や運転者による入力手段など他の手段でもよく、さらにその認識手段は、上記の開始決定手段に兼用されていてもよい。
【００５６】
【発明の効果】
以上説明したように、本発明の駐車支援装置によれば、加速度センサによる測定値から車両の算出移動距離を獲得しているため、高精度の車輪速センサを必要とすることなく、精度の高い車両位置の特定が可能であり、正確な初期停止位置の把握が可能となっている。また、かかる算出移動距離と車両の側方の障害物までの距離とに基づいて初期停止位置を把握し、その初期停止位置とヨー角検出手段で検出されたヨー角とに基づいて後退駐車をする一旦停止の適正なタイミングを案内手段を介して運転者に提供するので、予め設定された初期停止の基準位置に車両を正確に停止させなくても、運転者に大きな負担をかけることなく駐車の際の運転操作を的確に案内することができる。
さらに、適正な初期停止位置を案内するようにすれば、後退駐車の際の操作回数が削減され、運転者の負担をさらに低減することが可能となる。
【図面の簡単な説明】
【図１】 この発明の実施の形態１に係る駐車支援装置の構成を示すブロック図である。
【図２】 実施の形態１における縦列駐車時の車両の位置を段階的且つ模式的に示す図である。
【図３】 実施の形態１における縦列駐車時の初期停止位置に至る手前の地点に車両が位置した状態を示す平面図である。
【図４】 実施の形態１における縦列駐車時の初期停止位置に車両が位置した状態を示す平面図である。
【図５】 実施の形態１における超音波センサの位置に対する測定距離を示すグラフである。
【図６】 加速度センサにより測定された加速度と、速度及び距離との関係を示すと共に、算出移動距離と実測移動距離との関係を示すグラフである。
【図７】 実施の形態２における縦列駐車時の各位置に車両が位置した状態を示す平面図である。
【図８】 実施の形態２における超音波センサの位置に対する測定距離を示すグラフである。
【図９】 実施の形態３における縦列駐車時の車両の位置を段階的且つ模式的に示す図である。
【図１０】 実施の形態３における駐車中の車両の後端から適切な初期停止位置の前端までの前方距離Ｄとその後の旋回角度γの車間距離Ｂに対する関係を示すグラフである。
【図１１】 実施の形態４における適切な初期停止位置の演算方法を示す図である。
【図１２】 実施の形態４における適切な初期停止位置の演算方法を示す図である。
【図１３】 実施の形態４における適切な初期停止位置の演算方法を示す図である。
【図１４】 実施の形態４における適切な初期停止位置の演算方法を示す図である。
【図１５】 実施の形態６に係る駐車支援装置の構成を示すブロック図である。
【符号の説明】
１ コントローラ、１ｂ 補正部、２ ヨーレートセンサ、４ 縦列モードスイッチ、６ スピーカ、７ 超音波センサ、８ 車輪速センサ、９ 加速度センサ、１０，２０，３０ 車両、１１ 光センサ、Ｐ１ 初期停止位置、Ｑ１ 切り返し位置、Ｒ１ 駐車スペース内の車両位置。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a parking assistance device that guides a driver to perform a driving operation during parking.
[0002]
[Prior art]
Conventionally, there has been a parking assistance device that guides a vehicle to a parking frame along a predetermined trajectory, and such a device is provided with means for specifying the position of the vehicle to perform parking guidance. Yes. Further, as means for specifying the position of the vehicle, a wheel speed sensor that detects the rotational speed of the wheel, an ultrasonic sensor that detects a distance from an obstacle around the vehicle, and the like have been used (for example, patents). Reference 1 and 2).
[0003]
[Patent Document 1]
JP 2001-334897 A
[Patent Document 2]
Japanese Patent Laid-Open No. 11-15740
[0004]
[Problems to be solved by the invention]
However, in the parking assistance device, more accurate vehicle position specification is required. However, conventionally used wheel speed sensors tend to have insufficient resolution. In addition, it is possible to newly install a wheel speed sensor capable of high-accuracy measurement, but in this case, a significant change is required on the vehicle side, and a problem that leads to an increase in cost arises. On the other hand, detection by an ultrasonic sensor is based on the premise that there is an object in the detection direction, which contributes to the specification of the vehicle position in the vehicle width direction, but it is common to detect the travel distance in the vehicle front-rear direction, etc. It was difficult.
Therefore, an object of the present invention is to provide a parking assistance device that can specify the position of a vehicle and guide a driver to a necessary driving operation without forcing the mounting of a high-accuracy wheel speed sensor.
[0005]
[Means for Solving the Problems]
In order to achieve the above-described object, a parking assistance device of the present invention is a parking assistance device that guides a vehicle to a parking frame along a predetermined trajectory from an initial stop position, wherein the initial stop position and the parking frame A recognition means for recognizing the positional relationship, an acceleration sensor for measuring the longitudinal acceleration of the vehicle, a yaw angle detection means for detecting the yaw angle of the vehicle, and for outputting driving operation guidance information to the driver The calculated travel distance of the vehicle is calculated by second-order integrating the acceleration measured by the guide means and the acceleration sensor, and the calculated travel distance and the positions of the initial stop position and the parking frame recognized by the recognition means And a controller for determining the guidance information based on the initial stop position and the yaw angle detected by the yaw angle detection means.
[0006]
The parking assist device further includes a pulse output type wheel speed sensor, and the controller calculates the vehicle travel distance obtained from the measured travel distance of the vehicle obtained from the output pulse of the wheel speed sensor and the measurement result of the acceleration sensor. You may make it provide the correction | amendment part which compares with a movement distance and correct | amends so that the calculated movement distance after that may become an appropriate value.
In addition, the parking assist device further includes a side distance sensor, and the recognition means is based on the calculated moving distance and a distance to the obstacle on the side of the vehicle measured by the side distance sensor. It is preferable to know the stop position.
The lateral distance sensor also functions as a start determination unit that determines the measurement start of the acceleration sensor, and the calculated movement distance is an acceleration measured by the acceleration sensor from a measurement start timing determined by the start determination unit. May be the vehicle travel distance from the measurement start timing obtained by second-order integration.
Preferably, the lateral distance sensor is an ultrasonic sensor, an optical sensor, or a sensor using electromagnetic waves.
The recognizing means is an image recognizing means, and the image recognizing means recognizes a positional relationship between the initial stop position and the parking frame, and also functions as a start determining means for determining the measurement start of the acceleration sensor, The calculated moving distance may be a moving distance of the vehicle from the measurement start timing obtained by second-order integration of the acceleration measured by the acceleration sensor from the measurement start timing determined by the start determining means.
An input means for receiving a determination instruction from the driver may be further provided as a start determination means for determining the measurement start of the acceleration sensor.
[0007]
The controller shifts the difference between the actual initial stop position and the initial stop reference position based on the positional relationship between the initial stop position recognized by the recognition means and the parking frame and the calculated movement distance. It is possible to configure so as to calculate an appropriate timing for stopping once to perform reverse parking based on the measured deviation and the yaw angle detected by the yaw angle detection means.
In this case, the controller has reached the initial stop position based on the positional relationship between the initial stop position recognized by the recognition means and the parking frame and the calculated movement distance during the forward movement to the initial stop position. When the determination is made, the driver may be informed of the stop through the guiding means.
The controller advances the vehicle from the initial stop position with the maximum steering angle and stops at the reverse start position, and from the reverse start position to maximize the steering angle in the reverse direction, reverses the vehicle, stops at the return position, and returns. Guidance information can be provided to the driver via the guide means so that the steering angle is maximized in the opposite direction from the position and the vehicle is moved backward to reach the target parking space.
Furthermore, the controller sets a target parking space based on the positional relationship between the initial stop position and the parking frame recognized by the recognition means during the forward movement up to the initial stop position, and the calculated movement distance. It is also possible to calculate the inclination of the vehicle with respect to the vehicle, and to calculate the appropriate timing of the stop once by adding this inclination to the deviation between the actual initial stop position and the initial stop reference position.
[0008]
Further, the controller calculates an appropriate initial stop position based on the positional relationship between the initial stop position recognized by the recognition means and the parking frame, and determines that the initial stop position has been reached based on the calculated moving distance. In this case, the driver can be instructed to stop the vehicle through the guiding means.
The controller sets the steering angle to the maximum from the initial stop position, moves the vehicle backward and stops at the turn-back position, and sets the steering angle to the reverse direction to maximize the steering angle from the turn-back position to move the vehicle backward to reach the target parking space. Guidance information can be provided to the driver via the guidance means.
Furthermore, the controller sets a target parking space based on the positional relationship between the initial stop position and the parking frame recognized by the recognition means during the forward movement up to the initial stop position, and the calculated movement distance. May be calculated, and an appropriate initial stop position corresponding to the inclination may be calculated.
The controller can store a history of the positional relationship between the initial stop position recognized by the recognition means and the parking frame and the calculated movement distance, and calculate an appropriate initial stop position based on the history.
[0009]
Note that the length of the target parking space based on the positional relationship between the initial stop position recognized by the recognition means and the parking frame and the calculated movement distance when the controller moves forward to the initial stop position. You can also measure the thickness.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 shows the configuration of a parking assist apparatus according to Embodiment 1 of the present invention. The controller 1 is connected to a yaw rate sensor 2 that detects an angular velocity of the vehicle in the yaw angle direction, and the vehicle performs parallel parking with the parallel mode switch 3 for informing the controller 1 that the vehicle performs parallel parking. Is connected to a switch module 5 including a column mode switch 4 for informing the controller 1 of the above. Furthermore, a speaker 6 is connected to the controller 1 as guidance means for guiding driving operation information to the driver.
[0011]
Further, the controller 1 includes an ultrasonic sensor 7 as a side distance sensor for measuring a distance to an obstacle on the side of the vehicle, a wheel speed sensor 8 for measuring a moving distance of the vehicle, and a vehicle longitudinal direction. An acceleration sensor 9 for measuring acceleration is connected. The wheel speed sensor 8 is an existing pulse output type sensor that detects the rotational speed of a vehicle wheel, and has an output of 4 pulses per wheel rotation. Therefore, when the outer circumference of the wheel is about 160 cm, that is, when the vehicle travels about 160 cm by one rotation of the wheel, the resolution of the wheel speed sensor 8 is about 40 cm. Therefore, the wheel speed sensor 8 is not particularly high-accuracy prepared for parking assistance, but a wheel speed sensor 8 that has been conventionally used for vehicle speed display in a speedometer is employed. The output signal of the wheel speed sensor 8 is used for both information for displaying the vehicle speed on the speedometer and correction information when calculating the moving distance of the vehicle using the acceleration sensor 9 as will be described later.
The switch module 5 and the speaker 6 are disposed in the driver's seat, and the ultrasonic sensor 7 is installed on the front end side of the vehicle.
[0012]
The controller 1 includes a CPU (not shown), a ROM storing a control program, and a working RAM.
The ROM stores data of a minimum turning radius Rc when the vehicle handle is turned to the maximum and the vehicle turns, and stores a control program for assisting parking in parallel parking and parallel parking. The CPU operates based on a control program stored in the ROM. The controller 1 calculates the yaw angle of the vehicle from the angular velocity of the vehicle input from the yaw rate sensor 2, calculates the turning angle of the vehicle, and outputs information about the operation method and operation timing at each step during parking operation to the speaker 6. To do.
[0013]
Here, with reference to FIG. 2, a description will be given of what kind of locus the parking assistance apparatus of this embodiment draws in the vehicle to support parallel parking.
Assume that the vehicle 10 is parked in the parking frame T so that the rear left end of the vehicle 10 coincides with the corner S2 at the back of the parking frame T that is the final parking position. In this state, the rear axle center MO of the vehicle 10 at the vehicle position M1 is set as an origin, the Y axis is taken in the backward direction of the vehicle 10 parallel to the road, and the X axis is taken at right angles to the Y axis. The coordinates of the corner at the back of the parking frame T are S2 (W2 / 2, a2). Here, a2 and W2 indicate the rear overhang and the vehicle width of the vehicle 10, respectively.
The vehicle 10 at the vehicle position J1 moves forward while turning at a radius Rc with the steering angle of the steering wheel set to the right maximum, and moves backward while turning at the radius Rc with the steering angle set to the left maximum at the vehicle position K1. When the vehicle position L1 is reached, the steering angle is maximized on the right side, the vehicle turns backward with a radius Rc, and the vehicle is properly parked at the vehicle position M1 in the parking frame T.
[0014]
First, tandem parking is started with the vehicle 20 parked at a predetermined position in front of the parking frame T as a guide, with the vehicle 10 stopped at the vehicle position J1 as an initial stop position.
The vehicle position J1 is a position where the Y coordinate of the position DR of the driver of the vehicle 10 coincides with the Y coordinate of the rear end 20a of the parked vehicle 20, and is parallel to the parking frame T. Is a position where the predetermined vehicle interval d is. Therefore, the coordinates (JOx, JOy) of the rear axle center JO at the vehicle position J1 are uniquely determined from the coordinates of the rear end portion 20a of the vehicle 20, the relationship between the driver position DR and the rear axle center JO, and the vehicle distance d. .
The vehicle 10 at the vehicle position J1 moves forward to the vehicle position K1 while turning at a radius Rc with the steering angle of the steering wheel being maximized to the right. In this case, the turning center is C3 and the turning angle is β. Further, the vehicle 10 at the vehicle position K1 moves backward to the vehicle position L1 while turning at the radius Rc with the steering angle set to the left maximum. In this case, the turning center is C4 and the turning angle is δ. Furthermore, the steering wheel is turned back in the opposite direction at the vehicle position L1, and the vehicle is moved backward to the vehicle position M1 while turning at the radius Rc with the maximum steering angle on the right side. The turning center at that time is C5, and the turning angle is α.
Further, the rear axle centers at vehicle positions K1 and L1 are denoted as KO and LO, respectively.
[0015]
The turning angles α, β, δ are
δ = α-β
There is a relationship.
The coordinates (C5x, C5y) of the turning center C5 are
C5x = −Rc
C5y = 0
It is represented by
The coordinates (C4x, C4y) of the turning center C4 are
C4x = C5x + (Rc + Rc) ・ cosα = −Rc + 2Rc ・ cosα
C4y ＝ C5y− (Rc + Rc) ・ sinα = −2Rc ・ sinα
It is represented by
The coordinates (C3x, C3y) of the turning center C3 are
C3x = C4x− (Rc + Rc) ・ cosβ = −Rc + 2Rc ・ cosα−2Rc ・ cosβ
C3y ＝ C4y ＋ (Rc + Rc) ・ sinβ ＝ −2Rc ・ sinα ＋ 2Rc ・ sinβ
It is represented by
The coordinates (JOx, JOy) of the rear axle center JO at the vehicle position J1 are

It is represented by
[0016]
Here, when the equations (1) and (2) are transformed using the trigonometric formula,
tan (α / 2 + β / 2) = JOx / JOy
sin²(Α / 2-β / 2) = (JOx²+ JOy²) / (16Rc²)
Thus, α and β can be calculated using the coordinates (JOx, JOy) of the known rear axle center JO.
The coordinates (JOx, JOy) of the rear axle center JO are set as standard values that allow the vehicle 10 to be parked behind the vehicle 20 with a reasonable operation, for example, values of JOx = 2.3 m and JOy = 4.5 m are set. Has been.
The standard coordinates JOx and JOy of the rear axle center JO are desirably set in accordance with the vehicle grade, steering characteristics, etc. of the vehicle 10.
[0017]
Next, the operation | movement at the time of parallel parking of the parking assistance apparatus which concerns on Embodiment 1 is demonstrated.
First, as shown in FIG. 3, the vehicle 10 is moved straight forward in parallel with the road, that is, in parallel with the target parking frame T, and the Y coordinate of the driver's position DR is the rear end of the parked vehicle 20. It coincides with the Y coordinate of 20a, and the vehicle 10 moves toward the vehicle position J1 with respect to the vehicle 20 such that the vehicle distance d is, for example, 50 cm. At this time, the distance to the obstacle on the side of the vehicle, for example, the parked vehicle 20, is determined by the ultrasonic sensor 7 installed on the front end side of the vehicle while moving forward, and the positional relationship between the initial stop position and the parking frame. Is measured continuously as The vehicle 10 gradually approaches the vehicle position J1, and reaches the position where the Y coordinate of the driver's position DR coincides with the Y coordinate of the rear end 20a of the parked vehicle 20, as shown in FIG.
[0018]
Here, as the vehicle 10 moves forward, the measurement distance x to the obstacle corresponding to the position of the ultrasonic sensor 7 is shown as in FIG. Since there is no vehicle in the target parking frame T, the measurement distance x is very large when passing through the side of the parking frame T, but the Y coordinate of the ultrasonic sensor 7 as shown in FIG. Reaches the coordinate y1 that coincides with the Y coordinate of the rear end 20a of the parked vehicle 20, the measurement distance x decreases rapidly and becomes the distance from the ultrasonic sensor 7 to the vehicle 20. The measurement distance x at this time is represented by the sum of the distance 50 cm from the vehicle 20 that is the reference position ST of the initial stop and the deviation dx1 in the x direction.
[0019]
In this way, from the sudden change in the measurement distance x of the ultrasonic sensor 7, the controller 1 can recognize that the ultrasonic sensor 7 in the vehicle 10 has reached the coordinate y1, as indicated by the solid line in FIG. it can.
[0020]
In addition, the ultrasonic sensor 7 also functions as a start determination unit that determines the measurement start timing of acceleration by the acceleration sensor 9. That is, the position where the front end of the vehicle 10 is aligned with the rear end 20a of the parked vehicle 20 in the Y coordinate direction as shown in FIG. Measurement of acceleration by the acceleration sensor 9 is started. The acceleration sensor 9 outputs an output value related to acceleration as shown by a solid line in FIG. The controller 1 obtains the speed by time-integrating the output value related to the acceleration. Specifically, the calculation unit 1a in the controller 1 calculates the vehicle speed using a calculation formula represented by Vt = Kv · ΣEt. Here, Et is an output value related to acceleration every 20 ms in the present embodiment, Kv is a coefficient for speed calculation, and Vt is the speed of the vehicle. Thereby, the speed of the vehicle as shown by the alternate long and short dash line in FIG. 6 is obtained. Further, the controller 1 obtains the distance by integrating the obtained speed with time. Specifically, the speed of the vehicle is calculated using a calculation formula represented by Dt = Kd · ΣVt. Here, Vt is a calculated value of speed every 20 ms in the present embodiment, Kd is a coefficient for calculating distance, and Dt is a calculated moving distance of the vehicle. Thereby, the calculated movement distance of the vehicle as shown by the two-dot chain line in FIG. 6 is obtained.
In this way, in the controller 1, the calculated travel distance of the vehicle from the vehicle position at the measurement start timing determined by the output result of the ultrasonic sensor 7 is obtained by second-order integration of the acceleration measured by the acceleration sensor 9. It has been calculated.
[0021]
Therefore, the controller 1 stores the length LD from the front end of the vehicle 10 to the driver's position DR in advance and monitors the calculated travel distance of the vehicle 10 obtained by the second-order integration as described above. A specific stop sound is emitted to the driver via the speaker 6 when the vehicle 10 moves forward by a distance LD from when the sound wave sensor 7 reaches the coordinate y1. The driver who hears the stop sound stops the vehicle 10. As a result, the Y coordinate of the driver's position DR coincides with the Y coordinate of the rear end 20a of the parked vehicle 20, and this is set as the initial stop position. The measurement distance x by the ultrasonic sensor 7 at this time is represented by the sum of the distance 50 cm from the vehicle 20 that is the reference position ST of the initial stop and the deviation dx2 in the x direction.
[0022]
Since it is difficult to accurately position the vehicle 10 at the initial stop reference position ST, the above-described misalignments dx1 and dx2 are likely to occur. The deviation dx1 and the deviation dx2 are equal to each other when the vehicle 10 is traveling in parallel to the parked vehicle 20, but are different from each other when the vehicle 10 is traveling obliquely with a certain inclination. . Since the distance between the coordinates y1 and y2 is the LD stored in the controller 1 in advance, the inclination of the initial stop position of the vehicle 10 with respect to the reference position ST is determined from the deviations dx1 and dx2 and the distance LD. Can be sought.
Therefore, when the driver operates the tandem mode switch 4 while stopped at the initial stop position, the controller 1 determines from the deviations dx1 and dx2 measured in this way and the standard coordinates JOx and JOy of the rear axle center JO. Then, the coordinates (JOx + dx, JOy + dy) of the rear axle center JO ′ of the actual initial stop position are obtained, and the turning angles α, β, and δ are calculated so that the parking frame T can be properly parked in parallel.
[0023]
Further, based on the operation of the column mode switch 4, the controller 1 sets the initial stop position as a position where the yaw angle of the vehicle is 0 degree and starts a program for parallel parking. The driver steers the steering wheel of the vehicle 10 to the maximum on the right side to turn it fully, and advances the vehicle 10 as it is. The controller 1 calculates the yaw angle of the vehicle from the angular velocity of the vehicle 10 input from the yaw rate sensor 2, and compares this yaw angle with the calculated value of the turning angle β. As the vehicle 10 approaches the vehicle position K1 that is the reverse start position from the initial stop position, the controller 1 notifies that the vehicle position K1 has been approached based on the difference between the yaw angle and the calculated turning angle β. The driver is notified via the speaker 6 of the information and the arrival information notifying that the vehicle position K1 has been reached.
For example, an intermittent sound “beep” is emitted from the speaker 6 as the approach information, and the intermittent sound and the blinking cycle become shorter as the difference between the yaw angle and the turning angle β decreases. When the difference between the yaw angle and the turning angle β disappears, a continuous sound “pea” is emitted from the speaker 6 as arrival information.
[0024]
The driver stops the vehicle 10 at the vehicle position K1 according to the arrival information. Next, the driver steers the steering wheel all the way to the left to bring it to the full cut state, and moves the vehicle 10 backward as it is. The controller 1 compares the yaw angle of the vehicle with the value of the calculated turning angle α (= β + δ). As the vehicle 10 approaches the vehicle position L1 that is the turning position from the vehicle position K1, that is, as the vehicle yaw angle approaches the calculated turning angle α, the controller 1 calculates the turning angle calculated as the yaw angle. Based on the difference from α, the driver is informed of the approach information that informs that the vehicle position L1 is approached and the arrival information that informs that the vehicle position L1 is reached via the speaker 6.
[0025]
The driver stops the vehicle 10 at the vehicle position L1 according to the arrival information. Next, the driver turns the steering wheel in the opposite direction at the vehicle position L1, steers it to the right side to the full cut state, and moves the vehicle 10 as it is. As the yaw angle of the vehicle 10 approaches 0 degrees, the controller 1 approaches the vehicle 10 to approach the vehicle position M1 within the target parking frame T, and arrives to inform the vehicle position M1. Information is notified to the driver via the speaker 6. Accordingly, the driver can stop the vehicle 10 at the vehicle position M1 and complete the parking.
[0026]
When parking assistance is performed in this way, the calculated travel distance of the vehicle is obtained from the measured value by the acceleration sensor, so that it is possible to specify the vehicle position with high accuracy without requiring a high-precision wheel speed sensor. Yes, it is possible to accurately grasp the initial stop position. Further, the installation mode of the acceleration sensor is different from the installation mode of the wheel speed sensor, and can be stored together in the housing of the parking assistance device that houses the controller, and can be implemented without modification of the vehicle. Can be made and is inexpensive.
[0027]
Further, in the present embodiment, as described above, the controller 1 performs the actual measured movement of the vehicle obtained from the calculated movement distance of the vehicle obtained by second-order integration of the measurement result of the acceleration sensor 9 and the output pulse of the wheel speed sensor 8. A correction unit 1b that compares the distance and corrects the calculation formula of the calculated movement distance thereafter is provided. That is, as shown in FIG. 6, the inter-pulse travel distance LA from the rising edge of one pulse in the wheel speed sensor 8 to the rising edge of the next one pulse is equal to about 40 cm, which is the resolution in the wheel speed sensor 8 described above. On the other hand, the calculated movement distance LB calculated for the time from the rise of one pulse to the rise of the next one pulse should also be equal to about 40 cm. In practice, however, the calculated travel distance and the actually measured travel distance may differ greatly due to changes in sensor characteristics due to changes over time, temperature characteristics, and the influence of the calculation coefficients Kv and Kd used during integration. obtain. Therefore, in the present embodiment, the correction unit 1b in the controller 1 compares the calculated movement distance with the actually measured movement distance, and corrects the calculation coefficient to a more appropriate value at any time based on the result. To go. Therefore, even when the sensor characteristics change, it is possible to perform distance measurement with high accuracy, and consequently, it is possible to perform parking guidance with high accuracy. In addition, such correction may be performed by comparing each pulse or a plurality of pulses, and correcting each time, or comparing each pulse or a plurality of pulses and averaging based on a plurality of comparison results. It may be a way to correct by correcting.
[0028]
Embodiment 2. FIG.
Although the parking assistance apparatus which concerns on Embodiment 2 has the structure similar to the parking assistance apparatus of Embodiment 1 shown in FIG. 1, as FIG. 7 shows, the parking frame T used as the target This is effective not only when the vehicle 20 is already parked in front but also when the vehicle 30 is parked behind.
First, the distance from the side of the vehicle 30 parked behind the parking frame T to the obstacle on the side of the vehicle is continuously measured by the ultrasonic sensor 7 while the vehicle 10 advances straight in parallel with the road. . The distance measurement by the ultrasonic sensor 7 continues until the vehicle 10 reaches the initial stop position, that is, until the Y coordinate of the driver's position DR matches the Y coordinate of the rear end 20a of the parked vehicle 20. Done.
[0029]
At this time, as the vehicle 10 moves forward, the distance x measured by the ultrasonic sensor 7 is shown as shown in FIG. Initially, the distance to the vehicle 30 parked behind the parking frame T is measured, but the Y coordinate of the ultrasonic sensor 7 reaches a coordinate y0 that matches the Y coordinate of the front end 30a of the parked vehicle 30. Since the vehicle does not exist after the measurement, the measurement distance x becomes a very large value. Further, when the Y coordinate of the ultrasonic sensor 7 reaches a coordinate y1 that coincides with the Y coordinate of the rear end 20a of the vehicle 20 parked in front of the parking frame T, the measurement distance x is drastically decreased and the ultrasonic sensor. 7 to the vehicle 20. Therefore, the controller 1 can recognize that the ultrasonic sensor 7 has reached the coordinates yo and y1 from the sudden change in the measurement distance x, and the distance PSL that the vehicle 10 has moved during this time is the same as that of the first embodiment. Similarly, it can be calculated by second-order integration of acceleration measured by the acceleration sensor 9. This distance PSL represents the length of the parking space formed in the parked vehicles 30 and 20.
[0030]
After the ultrasonic sensor 7 reaches the coordinate y1, as in the first embodiment, the vehicle 10 moves forward by the distance LD, and when the ultrasonic sensor 7 reaches the coordinate y2, the driver is specified via the speaker 6. A stop sound is emitted. The driver who hears the stop sound stops the vehicle 10. As a result, the Y coordinate of the driver's position DR coincides with the Y coordinate of the rear end 20a of the parked vehicle 20, and this is set as the initial stop position.
When the driver operates the tandem mode switch 4 while stopped at the initial stop position, the controller 1 starts from the actual initial stop position based on the measured deviations dx1 and dx2 and the length PSL of the parking space. The turning angles α, β, and δ are calculated so that the parking frames T can be properly parked in parallel.
Based on the turning angles α, β, and δ calculated in this way, the controller 1 provides the driver with an appropriate timing for temporary stop in the full cut state via the speaker 6, as in the first embodiment. Thus, the driver can complete the parallel parking in the parking frame T.
[0031]
Embodiment 3 FIG.
The parking assistance apparatus according to the third embodiment has the same configuration as that of the parking assistance apparatus according to the first embodiment shown in FIG. 1, but the vehicle is stopped at a preset reference position for initial stop. Instead, the controller 1 calculates an appropriate initial stop position based on the distance x to the obstacle on the side of the vehicle measured by the ultrasonic sensor 7 and guides it to the driver. Furthermore, the guidance is such that the steering angle is maximized from the initial stop position and the vehicle is moved backward to stop at the turn-back position, and the steering angle is maximized in the reverse direction from the turn-back position and the vehicle is moved backward to reach the target parking space. Information is provided to the driver.
[0032]
An appropriate initial stop position calculation method will be described with reference to FIG. The inter-vehicle distance between the vehicle 10 and the parked vehicle 20 is B. When the width of these vehicles is W2, respectively, the distance DX to move the vehicle 10 in the X direction by the parking operation is
DX = B + W2
It is expressed. If the turning angle when the rear axle center of the vehicle 10 moves from P0 at the initial stop position P1 to Q0 at the turn-back position Q1 is γ, and the minimum turning radius of the rear axle center is Rc,
DX = 2Rc ・ (1−cosγ)
It becomes.
Here, since the distance DX can be measured by the ultrasonic sensor 7 and the minimum turning radius Rc is known, the turning angle γ can be calculated from the above equation.
When the turning angle γ is obtained,
DY = 2Rc · sinγ
Further, the distance DY in the Y direction between the positions P0 and R0 of the rear axle center can be obtained.
[0033]
Let F be the interference margin between the right rear end Z of the parked vehicle 20 and the left front end of the vehicle 10 when the vehicle 10 turns. In FIG. 9, since both interfere with each other, F takes a negative value.
The turning radius Rfl at the left front end of the vehicle 10 is L, where the total length of the vehicle 10 is L.
Rfl = {(Rc + W2 / 2)²+ (L−a2)²}^1/2
It is expressed. On the other hand, the distance ZC7 between the right rear end Z of the vehicle 20 and the turning center C7 of the vehicle 10 is obtained by using the distance E in the Y direction between the right rear end Z of the vehicle 20 and the turning center C7 of the vehicle 10. ,
ZC7 = {(Rc−W2 / 2)²+ E²}^1/2
It becomes.
[0034]
The interference margin F is
F = ZC7−Rfl
Therefore, the value of the distance E can be determined by substituting a specific numerical value, for example, 40 cm, into F.
Here, since the distance DY is already obtained, the forward distance D from the rear end of the parked vehicle 20 to the front end of the vehicle 10 at the initial stop position P1 is:
D = DY−E + L−a2
It becomes. Thus, the front distance D can be obtained from the inter-vehicle distance B between the vehicle 10 and the parked vehicle 20.
[0035]
Next, the operation at the time of parallel parking of the parking assistance apparatus according to the third embodiment will be described.
First, the vehicle 10 is moved forward in parallel with the road, and the tandem mode switch 4 is operated while passing the side of the parking space. Thereby, the measurement of the distance to the parked vehicle 20 is continuously performed by the ultrasonic sensor 7 installed on the front end side portion of the vehicle 10, and the controller 1 performs ultrasonic measurement similarly to the first embodiment. Recognizing that the sensor 7 has reached the rear end position of the vehicle 20 and measuring the inter-vehicle distance B between the vehicle 10 and the vehicle 20, the appropriate initial stop position P1 from the rear end of the vehicle 20 is measured according to the above procedure. The forward distance D to the front end and the subsequent turning angle γ can be determined.
[0036]
The controller 1 calculates the moving distance of the vehicle 10 by second-order integrating the acceleration measured by the acceleration sensor 9 as in the first embodiment, monitors the moving distance, and the ultrasonic sensor 7 is parked. A specific stop sound is emitted to the driver via the speaker 6 when the vehicle 10 moves forward by a forward distance D from the time when the rear end position of the vehicle 20 is reached. The driver who hears the stop sound stops the vehicle 10. As a result, the vehicle 10 stops at an appropriate initial stop position P1. At this time, the controller 1 resets the yaw angle of the vehicle 10 by the yaw rate sensor 2.
[0037]
Thereafter, the driver steers the steering wheel of the vehicle 10 to the maximum on the left side to turn it fully, and moves the vehicle 10 backward as it is. The controller 1 compares the yaw angle of the vehicle with the determined value of the turning angle γ, and when the yaw angle approaches the turning angle γ, it outputs approach information via the speaker 6, and further the yaw angle becomes the turning angle γ. At this point, it is determined that the switching position Q1 has been reached, and the arrival information is output via the speaker 6.
The driver stops the vehicle 10 at the turn-back position Q1 according to the arrival information, turns the steering wheel back in the opposite direction, steers it to the right side to the full cut state, and moves the vehicle 10 as it is. As the yaw angle of the vehicle 10 approaches 0 degrees, the controller 1 indicates that the vehicle 10 has approached the vehicle position R1 in the target parking space, and the arrival information that indicates that the vehicle 10 has reached the vehicle position R1. To the driver via the speaker 6. Thus, the driver can stop the vehicle 10 at the vehicle position R1 and complete the parking.
[0038]
The relationship between the distance D from the rear end of the parked vehicle 20 to the front end of the appropriate initial stop position P1 and the subsequent turning angle γ with respect to the inter-vehicle distance B is shown in FIG. To be confirmed.
Also in this third embodiment, as in the second embodiment, the length of the target parking space is measured at the time of linear advance toward the initial stop position to guide the possibility of parking, or parked backward It is possible to warn of interference with obstacles such as vehicles.
[0039]
Embodiment 4 FIG.
The fourth embodiment is useful in the third embodiment when the direction of the straight advance toward the initial stop position is not parallel to the parked vehicle 20 and has an inclination angle ε. As shown in FIG. 10, the position P <b> 2 of the vehicle 10 that has stopped by tilting by the angle ε can be considered as a state in which the parking operation has retreated from the position P <b> 1 stopped in parallel with the parked vehicle 20.
[0040]
Assuming that the vehicle 10 at the position P1 retreats by the angle ε at the turning radius Rc and reaches the position P2, the coordinates (X1f, Y1f) of the left front end of the vehicle 10 at the position P2 are the vehicle 10 at the position P1 with the turning center as the origin. Using the coordinates (X0f, Y0f) of the left front end of
X1f ＝ X0f ・ cosε + Y0f ・ sinε
Y1f ＝ Y0f ・ cosε−X0f ・ sinε
It is expressed. Therefore,
The X-direction displacement ΔX1f of the left front end of the vehicle 10 between the positions P1 and P2 is
ΔX1f = X1f−X0f = Y0f ・ sinε−X0f ・ (1−cosε)
And expressed in terms of the actual vehicle 10 parameters,
ΔX1f ＝ (L−a2) ・ sinε− (Rc−W2 / 2) ・ (1−cosε)
It becomes.
[0041]
In the actual vehicle 10, for example, as shown in FIG. 12, when the horizontal distance when the rear end of the parked vehicle 20 is detected by the ultrasonic sensor 7 installed on the front end side portion of the vehicle 10 is A0. The horizontal distance B0 of the vehicle parallel to the vehicle 20 corresponding to this distance A0 is
B0 = A0−ΔX1f = A0− (L ・ a2) ・ sinε + (Rc−W2 / 2) ・ (1−cosε)
It becomes.
[0042]
By the way, as shown in FIG. 13, for example, the inclination angle ε is an inter-vehicle distance A1 with the vehicle 20 when the ultrasonic sensor 7 detects the rear end of the parked vehicle 20 and advances by H1. From the inter-vehicle distance A2 with the vehicle 20 when traveling by H2,
ε = tan^-1{(A2−A1) / H2}
It is obtained by.
[0043]
Next, as shown in FIG. 14, in the graph showing the relationship between the front distance D and the turning angle γ with respect to the inter-vehicle distance B, a straight line with an inclination ε extending from the point of the inter-vehicle distance B 0 when the front distance D is 0 and the front An appropriate forward distance Da when the vehicle is replaced with a vehicle parallel to the parked vehicle 20 can be obtained from the intersection with the curve representing the distance D. Further, an appropriate turning angle γa can be obtained from the intersection of a straight line drawn in parallel to the Y axis from the intersection of a straight line having an inclination ε and a curve representing the forward distance D and a curve representing the turning angle γ.
[0044]
In FIG. 11, the Y-direction displacement ΔY1f of the left front end of the vehicle 10 between the positions P1 and P2 is
ΔY1f = Y1f−Y0f = − {X0f · sinε + Y0f · (1−cosε)}
And expressed in terms of the actual vehicle 10 parameters,
ΔY1f ＝ − {(Rc−W2 / 2) ・ sinε + (L−a2) ・ (1−cosε)}
It becomes.
A vehicle that is inclined by the angle ε is considered to be positioned in front of the parked vehicle 20 by the Y-direction displacement ΔY1f, and therefore advances in the Y-direction by a distance obtained by subtracting the Y-direction displacement ΔY1f from the forward distance Da. The distance D1 represented by the following expression is in the oblique direction of the angle ε.

[0045]
In addition, as for the turning angle γ, since the vehicle has already been turned by an angle ε from a vehicle parallel to the parked vehicle 20,
γ1 ＝ γa−ε
Is the turning angle from the initial stop position tilted by the angle ε to the turn-back position.
The turning angle from the turn-back position to the target parking space is γa.
[0046]
Therefore, in the third embodiment, when it is determined that the straight forward direction toward the initial stop position is inclined at an angle ε with respect to the parked vehicle 20, the controller 1 is the same as in the first embodiment. The moving distance of the vehicle 10 calculated by second-order integration of the acceleration measured by the acceleration sensor 9 is monitored, and when the ultrasonic sensor 7 reaches the rear end position of the parked vehicle 20, the vehicle 10 Stop when the vehicle advances diagonally by the distance D1, steer the handle to the maximum left side from the initial stop position, stop again when the vehicle moves backward by the angle γ1, turn the handle back to the maximum right side, and complete the parking when the vehicle moves backward by the angle γa. The guidance information may be output to the driver.
[0047]
In the fourth embodiment, as in the second embodiment, the length of the target parking space is measured when the vehicle goes straight ahead toward the initial stop position to guide the possibility of parking. It is possible to warn of interference with obstacles such as parked vehicles.
In practice, the measurement of the inter-vehicle distance from the parked vehicle 20 by the ultrasonic sensor 7 is desirably performed according to the influence of the roundness of the corners of the vehicle and the characteristics of the sensor.
Further, although the case where the distance D1 and the angle γ1 are obtained geometrically has been described, it may be calculated analytically.
[0048]
Embodiment 5 FIG.
In the fifth embodiment, instead of starting the measurement of the distance to the parked vehicle 20 by operating the tandem mode switch 4 while passing the side of the parking space in the third and fourth embodiments described above, The distance to the obstacle on the side of the vehicle according to the travel distance is recorded by constantly measuring the distance to the obstacle on the side of the vehicle by the ultrasonic sensor 7 and calculating the moving distance based on the measurement result of the acceleration sensor 9. The initial stop position is calculated using the history.
[0049]
The controller 1 always operates the ultrasonic sensor 7 and the acceleration sensor 9, and based on signals input from these sensors, an obstacle on the side of the vehicle corresponding to the travel distance in the past predetermined time or the predetermined travel distance. Save the distance to history.
Passing the side of the parking space, the vehicle 10 is stopped at an appropriate position, for example, the side of the parked vehicle 20 like the initial stop position in the third and fourth embodiments, and the tandem mode switch 4 is operated. Thereby, the controller 1 calculates as described in the embodiment 3 or 4 based on the history of the distance to the obstacle on the side of the vehicle according to the travel distance for the predetermined time or the predetermined travel distance before the stop. A proper initial stop position for parallel parking in the parking space is calculated by the method.
[0050]
When the initial stop position is calculated, the controller 1 guides the driver via the speaker 6 so as to reach the initial stop position by moving forward or backward.
However, when the initial stop position cannot be calculated only with the history stored in the controller 1, the driver is guided through the speaker 6 so as to further advance straight forward or backward, and obtained during that time. The initial stop position is calculated by adding the relationship between the distance traveled and the distance to the obstacle to the stored history. Thereafter, the controller 1 guides the driver through the speaker 6 so as to reach the initial stop position by moving forward or backward.
[0051]
After the vehicle 10 stops at the initial stop position in this way, the controller 1 uses the speaker 6 so that the vehicle 10 reaches the turn-back position and further reaches the parking space in the same manner as in the third or fourth embodiment. And provide guidance information to the driver.
In addition, also in this fifth embodiment, as in the second to fourth embodiments, the length of the target parking space is measured at the time of linear advance toward the initial stop position, and guidance on whether or not parking is possible, It is possible to warn of interference with obstacles such as vehicles parked behind.
According to the fifth embodiment described above, an appropriate initial stop position is calculated based on the past history simply by stopping the vehicle 10 at an appropriate position and operating the column mode switch 4. An excellent parking assistance device is realized.
[0052]
Embodiment 6 FIG.
FIG. 15 shows the configuration of the parking assistance apparatus according to the sixth embodiment. The parking assist apparatus according to the sixth embodiment is the same as the apparatus according to the first embodiment shown in FIG. 1 except that the optical sensor 11 is installed as a lateral distance sensor instead of the ultrasonic sensor 7 at the front end side of the vehicle. It measures the distance to the side obstacles.
According to the sixth embodiment as well, similar to the first to fifth embodiments, an appropriate timing for temporary stop in the full cut state is provided to the driver via the speaker 6, and the parallel parking to the parking frame T is performed. Can be completed.
Even if the optical sensor 11 is used, it is possible to measure the length of the parking space and use it to calculate the turning angles α, β, and δ as in the second embodiment.
The optical sensor 11 can be composed of a combination of a light emitting means such as an LED or a laser diode and a light receiving means such as a phototransistor or a CCD device. Furthermore, instead of the optical sensor 11, a sensor using an electromagnetic wave other than light, such as a radar, may be used.
[0053]
In Embodiments 1 to 6 described above, when the turning angle is calculated by the controller 1, the turning angle that can be applied to the parking operation cannot be calculated due to a large deviation, or the maximum steering angle is maintained. However, when the vehicle 10 is turned at the turning angle, if the vehicle 10 is predicted to interfere with an obstacle such as the parked vehicle 20 during parallel parking, an alarm is issued to the driver via the speaker 6. It can also be configured as follows. In this way, it is possible to prevent an obstacle from being interfered with the turning angle calculated in consideration of the displacement of the initial stop position.
[0054]
In the first to sixth embodiments, the yaw rate sensor is used as the yaw angle detection means. However, the means for detecting the yaw angle may be a method using a position gyro or a rotation sensor attached to each of the left and right wheels, and the yaw angle sensor may detect the yaw angle based on the rotation difference between them. A method of detecting a corner may be used, and a method using a geomagnetic sensor or a GPS system may be used.
In the first to sixth embodiments, as the approach information and the arrival information, the volume and tone color of the sound emitted from the speaker 6 is changed or the sound having different contents is emitted for each vehicle position that is the target of approach or arrival. You may do it. The guiding means is not limited to the speaker, but may be a buzzer, an LED, or a lamp, and may display characters and marks on the display. Furthermore, vibration transmitted to the driver via a handle or the like may be used.
[0055]
Furthermore, in the above first to fourth embodiments, the ultrasonic sensor 7 functions as a start determination unit that determines the measurement start timing of acceleration by the acceleration sensor 9, but instead of this mode, the operation by the driver For example, a specific sensor other than an ultrasonic sensor for measuring a lateral distance from an obstacle, such as an input means such as a switch, a voice recognition means, an image recognition means, or the like can be adopted.
Moreover, in said Embodiment 1-4, although the side distance sensor, ie, the ultrasonic sensor 7, is used as a recognition means which recognizes the positional relationship of the said initial stop position and the said parking frame, this invention is However, the present invention is not limited to this, and other means such as an image recognition means or an input means by the driver may be used. Further, the recognition means may also be used as the start determination means.
[0056]
【The invention's effect】
As described above, according to the parking assistance device of the present invention, the calculated travel distance of the vehicle is obtained from the measurement value obtained by the acceleration sensor, so that a high-accuracy wheel speed sensor is not required and the accuracy is high. The vehicle position can be specified, and an accurate initial stop position can be grasped. Further, the initial stop position is grasped based on the calculated moving distance and the distance to the obstacle on the side of the vehicle, and the reverse parking is performed based on the initial stop position and the yaw angle detected by the yaw angle detecting means. Providing the driver with an appropriate timing for stopping once through the guide means, it is possible to park the vehicle without imposing a heavy burden on the driver even if the vehicle is not accurately stopped at the preset reference position for the initial stop. It is possible to accurately guide the driving operation at the time.
Furthermore, if an appropriate initial stop position is guided, the number of operations during reverse parking is reduced, and the burden on the driver can be further reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a parking assistance apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a diagram schematically showing the position of a vehicle at the time of parallel parking in Embodiment 1 in a stepwise manner.
FIG. 3 is a plan view showing a state in which the vehicle is located at a point before reaching an initial stop position at the time of parallel parking in the first embodiment.
4 is a plan view showing a state in which the vehicle is positioned at an initial stop position during parallel parking in Embodiment 1. FIG.
FIG. 5 is a graph showing a measurement distance with respect to the position of the ultrasonic sensor in the first embodiment.
FIG. 6 is a graph showing the relationship between the acceleration measured by the acceleration sensor, the velocity and the distance, and the relationship between the calculated moving distance and the actually measured moving distance.
7 is a plan view showing a state where a vehicle is positioned at each position during parallel parking in Embodiment 2. FIG.
FIG. 8 is a graph showing the measurement distance with respect to the position of the ultrasonic sensor in the second embodiment.
FIG. 9 is a diagram showing stepwise and schematic positions of a vehicle at the time of parallel parking in the third embodiment.
FIG. 10 is a graph showing a relationship between a front distance D from a rear end of a parked vehicle to a front end of an appropriate initial stop position and a subsequent turning angle γ with respect to an inter-vehicle distance B in the third embodiment.
FIG. 11 is a diagram illustrating a method of calculating an appropriate initial stop position in the fourth embodiment.
FIG. 12 is a diagram illustrating a method for calculating an appropriate initial stop position in the fourth embodiment.
FIG. 13 is a diagram illustrating a method of calculating an appropriate initial stop position in the fourth embodiment.
FIG. 14 is a diagram illustrating a method for calculating an appropriate initial stop position in the fourth embodiment.
FIG. 15 is a block diagram illustrating a configuration of a parking assistance apparatus according to a sixth embodiment.
[Explanation of symbols]
1 controller, 1b correction unit, 2 yaw rate sensor, 4 tandem mode switch, 6 speaker, 7 ultrasonic sensor, 8 wheel speed sensor, 9 acceleration sensor, 10, 20, 30 vehicle, 11 optical sensor, P1 initial stop position, Q1 Switching position, R1 Vehicle position in the parking space.

Claims (16)

A parking assistance device for guiding a vehicle to a parking position along a predetermined locus from an initial stop position,
Recognizing means for recognizing a positional relationship between the initial stop position and the parking position;
An acceleration sensor that measures the longitudinal acceleration of the vehicle;
Yaw angle detection means for detecting the yaw angle of the vehicle;
Guidance means for outputting driving operation guidance information to the driver;
The calculated movement distance of the vehicle is calculated by second-order integration of the acceleration measured by the acceleration sensor, and based on the calculated movement distance and the positional relationship between the initial stop position and the parking position recognized by the recognition means. And a controller that provides the guidance information based on the initial stop position and the yaw angle detected by the yaw angle detection means. It further comprises a pulse output type wheel speed sensor,
The controller compares the measured travel distance of the vehicle obtained from the output pulse of the wheel speed sensor with the calculated travel distance of the vehicle obtained from the measurement result of the acceleration sensor, and the calculated travel distance thereafter is an appropriate value. A correction unit that performs correction so that
The parking support apparatus according to claim 1, wherein The parking assist device further includes a lateral distance sensor, and the recognition means determines an initial stop position based on the calculated moving distance and a distance to an obstacle on the side of the vehicle measured by the lateral distance sensor. The parking support device according to claim 1, wherein the parking support device is grasped. The lateral distance sensor also functions as a start determination unit that determines the measurement start of the acceleration sensor, and the calculated movement distance is an acceleration measured by the acceleration sensor from a measurement start timing determined by the start determination unit. The parking assistance device according to claim 3, which is a moving distance of the vehicle from the measurement start timing obtained by second-order integration. The parking assistance device according to claim 3 or 4, wherein the lateral distance sensor is an ultrasonic sensor, an optical sensor, or a sensor using electromagnetic waves. The recognizing means is an image recognizing means, and the image recognizing means recognizes a positional relationship between the initial stop position and the parking position, and also functions as a start determining means for determining the measurement start of the acceleration sensor, The calculated travel distance is a travel distance of the vehicle from the measurement start timing obtained by second-order integration of the acceleration measured by the acceleration sensor from the measurement start timing determined by the start determination means. The parking assistance device according to claim 1 or 2. The parking assistance apparatus according to any one of claims 1 to 6, further comprising an input unit that receives a determination instruction from a driver as a start determination unit that determines measurement start of the acceleration sensor. The controller measures a deviation between the actual initial stop position and the initial stop reference position based on the positional relationship between the initial stop position recognized by the recognition means and the parking position and the calculated movement distance. The parking assist device according to any one of claims 1 to 7, wherein an appropriate timing for temporarily stopping the vehicle is calculated based on the deviation measured together with the yaw angle detected by the yaw angle detection means. When the controller determines that the initial stop position has been reached based on the positional relationship between the initial stop position and the parking position recognized by the recognition means and the calculated movement distance during the forward movement to the initial stop position The parking assistance device according to claim 8, wherein the vehicle is guided to the driver via the guide means to stop. The controller moves the vehicle forward from the initial stop position with the maximum steering angle and stops at the reverse start position, and reverses the vehicle with the steering angle maximized in the reverse direction from the reverse start position to stop at the turn-back position. 10. The parking assistance device according to claim 9, wherein guidance information is provided to the driver via the guide means so that the steering angle is maximized in the opposite direction from the position and the vehicle is moved backward to reach the target parking space. The controller is configured to provide a vehicle for a target parking space based on the positional relationship between the initial stop position recognized by the recognition unit and the parking position and the calculated movement distance during the forward movement up to the initial stop position. The parking assist device according to any one of claims 8 to 10, wherein a slope between the actual initial stop position and a reference position for the initial stop is added to the slope. The controller calculates an appropriate initial stop position based on the positional relationship between the initial stop position recognized by the recognition means and the parking position, and determines that the initial stop position has been reached based on the calculated movement distance The parking assistance device according to claim 8, wherein the vehicle is guided to the driver via the guide means to stop. The controller sets the steering angle to the maximum from the initial stop position, moves the vehicle backward and stops at the turn-back position, and sets the steering angle to the reverse direction to maximize the steering angle from the turn-back position to move the vehicle backward to reach the target parking space. The parking assistance device according to claim 12, wherein the parking information is provided to the driver via the guide means. The controller is configured to provide a vehicle for a target parking space based on the positional relationship between the initial stop position recognized by the recognition unit and the parking position and the calculated movement distance during the forward movement up to the initial stop position. The parking assistance device according to claim 12 or 13, wherein an inclination of the vehicle is calculated and an appropriate initial stop position corresponding to the inclination is calculated. The controller stores a positional relationship between the initial stop position recognized by the recognition means and the parking position and the calculated movement distance, and calculates an appropriate initial stop position based on the history. The parking assistance device according to any one of 14. The controller determines the length of the target parking space based on the positional relationship between the initial stop position and the parking position recognized by the recognition means during the forward movement to the initial stop position and the calculated movement distance. The parking assistance device according to any one of claims 1 to 15, which performs measurement.

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