JP3931495B2 - Vehicle pitch angle calculation device - Google Patents
Vehicle pitch angle calculation device Download PDFInfo
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- JP3931495B2 JP3931495B2 JP21844199A JP21844199A JP3931495B2 JP 3931495 B2 JP3931495 B2 JP 3931495B2 JP 21844199 A JP21844199 A JP 21844199A JP 21844199 A JP21844199 A JP 21844199A JP 3931495 B2 JP3931495 B2 JP 3931495B2
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
- B60G2400/25—Stroke; Height; Displacement
- B60G2400/252—Stroke; Height; Displacement vertical
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2401/00—Indexing codes relating to the type of sensors based on the principle of their operation
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- Vehicle Body Suspensions (AREA)
- Lighting Device Outwards From Vehicle And Optical Signal (AREA)
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は車両のピッチ角、すなわち車両における前後方向の水平方向に対する角度を演算する装置に関する。
【０００２】
【従来の技術】
車両のピッチ角は、例えば前照灯の角度を自動補正する装置（いわゆるヘッドランプ・オートレベライザ）等で必要とされる数値である。このピッチ角θは、車両の前輪位置における車高ｈｆと、後輪位置における車高ｈｒと、ホイールベース長ｗとに基づいて、下記（数１）式によって求めることができる。
θ＝ｔａｎ-1〔（ｈｆ−ｈｒ）／ｗ〕…（数１）
なお、前輪位置の車高ｈｆと後輪位置の車高ｈｒは、地上からの高さの値ではなく、車両の基準状態（例えば空荷状態）における車高位置（以下、基準位置と記載）からの変化量を用いる（以下ｈｆ、ｈｒを車高変化量と記載）。したがって車両の基準状態におけるピッチ角θは０度である。
車高変化量ｈｆ、ｈｒを検出するセンサとしては、各輪のサスペンション・アーム角度を検出して車高変化量に換算する車高センサが実用に供されている。
【０００３】
【発明が解決しようとする課題】
上記のごとき車高センサを用い、前記（数１）式のごとき演算を行なうことにより、ピッチ角を求めることができる。しかし、４輪駆動車のような複雑なサスペンション構造の車種では、車高センサを取り付けるのが難しいことがあり、かつ、工数やコストを削減するため、出来るだけ少ない車高センサでピッチ角を検出することが望まれる。
【０００４】
本発明は上記のごとき問題に鑑みてなされたものであり、車両の前後いずれか一方の車高変化量を検出することによってピッチ角を演算することの出来るピッチ角演算装置を提供することを目的とする。
【０００５】
【課題を解決するための手段】
上記の目的を達成するため、本発明においては、特許請求の範囲に記載するように構成している。すなわち、請求項１に記載の発明においては、所定距離ｗ離れた車両前後方向の２個所ＰｆとＰｒの内の何れか一方に車高検出手段を設けて車高変化量を検出し、車高検出手段を設置しない側の車高変化量として所定の車高変化量仮想値を設定し、前記実際の車高変化量検出値と前記車高変化量仮想値と前記距離ｗとに基づいて車両のピッチ角を演算する装置であって、前記車高検出手段で実際に検出した車高変化量の値が、空車状態の車高値を基準位置とした場合に車体が沈む方向で所定値未満の場合は、車高変化量仮想値を、空車状態を基準として車高が沈んだ状態の値とし、前記所定値以上の場合は、前記車高変化量仮想値を、空車状態を基準として車高が上がった状態の値に設定するように構成し、
前記Ｐｒとして後輪位置の車高変化量を検出する車高検出手段を設けた場合は、基準位置から車高が低くなる方への変化量を正とし、逆に高くなる方への変化量を負とした場合に、前記車高検出手段で実際に検出した後輪位置の車高変化量ｈｒの値が、所定値Ｒａ未満の場合は、前輪位置の車高変化量仮想値を正の所定値αとし、所定値Ｒａ以上の場合は負の所定値−βとして、下記の第１式、第２式に基づいてピッチ角θを演算し、
前記Ｐｆとして前輪位置の車高変化量を検出する車高検出手段を設けた場合は、基準位置から車高が低くなる方への変化量を正とし、逆に高くなる方への変化量を負とした場合に、前記車高検出手段で実際に検出した前輪位置の車高変化量ｈｆの値が、所定値Ｒａ未満の場合は、後輪位置の車高変化量仮想値を正の所定値αとし、所定値Ｒａ以上の場合は負の所定値−βとして、下記の第３式、第４式に基づいてピッチ角θを演算するように構成している。
θ＝ｔａｎ −１ 〔（α−ｈｒ）／ｗ〕 ただし、ｈｒ＜Ｒａ …第１式
θ＝ｔａｎ −１ 〔（−β−ｈｒ）／ｗ〕 ただし、ｈｒ≧Ｒａ …第２式
θ＝ｔａｎ −１ 〔（ｈｆ−α）／ｗ〕 ただし、ｈｆ＜Ｒａ …第３式
θ＝ｔａｎ −１ 〔（ｈｆ＋β）／ｗ〕 ただし、ｈｆ≧Ｒａ …第４式
【０００６】
上記のように構成したことにより、前後の一方にだけ車高検出手段を設けた構成で、通常の乗車状態の場合でフロントもリアも空車状態より沈む場合でも、リアに大量の貨物を搭載してリアが沈みフロントが浮き上がるような場合でも、常に正確なピッチ角を検出することが出来る。
【０００７】
【発明の効果】
本発明によれば、搭乗人員や貨物の重量に応じてピッチ角が大幅に変化した場合でも、車両の前後のいずれか一方に車高検出手段を設けるだけで正確なピッチ角を演算することができ、装置のコストを低減できる、という効果が得られる。
【０００８】
【発明の実施の形態】
本発明をヘッドランプ・オートレベライザに適用した実施の形態を説明する。ヘッドランプ・オートレベライザはピッチ角に応じて前照灯の角度を自動的に調節し、常に適切な照明が出来るように制御する装置である。なお、本発明はヘッドランプ・オートレベライザに限定されるものではなく、ピッチ角に基づいて制御を行なうすべての装置に応用することができる。
【０００９】
（第１の実施の形態）
図１は、本実施の形態における構成を示すブロック図である。この実施の形態は車両の後輪位置における車高変化量ｈｒを検出し、ピッチ角θを演算してヘッドランプの光軸を調節する装置である。
図１において、モータ１は右ヘッドランプ（図示省略）の角度を調節して光軸を上下するためのモータであり、位置センサ２は右ヘッドランプの光軸位置を検出するセンサである。また、モータ３は左ヘッドランプ（図示省略）の角度を調節して光軸を上下するためのモータであり、位置センサ４は左ヘッドランプの光軸位置を検出するセンサである。なお、ヘッドランプはシールドタイプ、セミシールドタイプなど、どのような形式であってもよい。また、ヘッドランプの光軸の具体的な調整方法は、ヘッドランプのリフレクタを傾動させてもよいし、ヘッドランプユニットを傾動させてもよい。
【００１０】
制御回路５は、コントローラ７からの光軸位置指令信号と位置センサ２からの光軸位置フィードバック信号とに基づいてモータ１を駆動制御し、右ヘッドランプの光軸の位置制御を行なう。制御回路６は、コントローラ７からの光軸位置指令信号と位置センサ４からの光軸位置フィードバック信号とに基づいてモータ３を駆動制御し、左ヘッドランプの光軸の位置制御を行なう。
【００１１】
イグニッションスイッチ８はイグニッションキーがＯＮ位置に設定されると閉路し、コントローラ７にバッテリ電源ＢＡＴを供給する。さらに、スモールランプスイッチ９はライトスイッチ（図示省略）の１段目で閉路し、スモールランプ（車幅灯）１０を点灯させるとともに、制御回路５、６にバッテリ電源ＢＡＴを供給する。
【００１２】
車高センサ１１は、例えば右後輪のサスペンションアームに取り付けられ、アーム角度を検出して右後輪位置における車高変化量ｈｒを検出する。すなわち、車高センサは１個だけ用いられ、後輪における車高変化量ｈｒのみを検出する。
【００１３】
コントローラ７は、マイクロコンピュータとその周辺部品から構成され、車高センサ１１の信号を用いて車両のピッチ角θを演算し、左右ヘッドランプの光軸位置を決定する。そして、制御回路５へは右ヘッドランプの光軸位置指令信号を出力し、制御回路６へは左ヘッドランプの光軸位置指令信号を出力する。
【００１４】
図２は、前輪位置Ｐｆと後輪位置Ｐｒにおける基準位置、検出位置および車高変化量の関係を示す図である。前輪位置Ｐｆと後輪位置Ｐｒの白丸はいずれも車両の基準状態における車高位置、すなわち基準位置を示す。またｗはホイールベース長である。
【００１５】
前記のように、車両が空荷の基準状態にあるときのピッチ角θは０である。そして搭乗人員や貨物の重量に応じて前後輪位置の車高が基準位置から変化すると、変化量に応じたピッチ角が発生する。後輪位置Ｐｒにおける黒丸は検出位置を示し、この検出位置と基準位置との距離が基準位置からの車高の変化量、すなわち後輪位置Ｐｒにおける車高変化量ｈｒであり、車高センサ１１でこの値を検出する。
【００１６】
なお、この明細書では基準位置から車高が低くなる方への変化量を正とし、逆に高くなる方への変化量を負とする。したがって、（数１）式によれば車両前部が沈み込むか、または車両後部が持ち上がる場合のピッチ角θが正となり、逆に、車両前部が持ち上がるか、または車両後部が沈み込む場合のピッチ角θが負となる。図２の場合のピッチ角θは図示のようになり、値は負である。
【００１７】
第１の実施の形態では、後輪位置Ｐｒの車高変化量を検出する車高センサ１１のみを設置し、前輪位置Ｐｆには車高センサを設置しない。したがって、前輪位置Ｐｆの車高を基準位置（変化量はゼロ）と仮定すれば、ｈｆ＝０であるから、車両のピッチ角θ’は下記（数２）式によって表される。
θ’＝ｔａｎ-1〔（０−ｈｒ）／ｗ〕…（数２）
ところが、一般に搭乗人員や貨物を積載すると、図３に示すように、実際の前輪位置Ｐｆ（前輪位置Ｐｆに黒丸印で示す）が基準位置（前輪位置に白丸で示す）よりも低くなる。そのため、実際にはｈｆが正の値を持つため、真のピッチ角θ”が計算上のピッチ角θ’（数２式）よりも絶対値で小さくなる。したがって計算上のピッチ角θ’に基づいてヘッドランプの光軸調節を行なうと、光軸を必要以上に下げてしまい、ヘッドランプが下を向き過ぎて前方照射距離が短くなってしまう。
【００１８】
そこで、図４に示すように、前輪位置Ｐｆにおける車高位置を、車高が低くなる方向に所定値だけ予め補正しておき、補正後の車高位置（前輪位置Ｐｆに黒丸で示す）と基準位置との距離、すなわち前輪位置Ｐｆにおける補正後の車高変化量仮想値αを用いて下記（数３）式によってピッチ角θを演算する。
θ＝ｔａｎ-1〔（α−ｈｒ）／ｗ〕…（数３）
なお、車高変化量仮想値αの値は、乗員や荷物で一般に前輪位置が下がると予想される程度の値（車種によって異なる値）に設定する。
【００１９】
上記のように、後輪位置における車高変化量の検出値ｈｒと、前輪位置における車高変化量仮想値αとに基づいて算出したピッチ角θに応じてヘッドランプの光軸位置を決定し、光軸制御を行なうことにより、搭乗人員や貨物の重量に応じて後輪位置の車高だけでなく前輪位置の車高も低くなった場合でも、正確なピッチ角を演算することができ、適正なヘッドランプの照射距離および範囲を確保できる。
【００２０】
ところで、リアのトランクに大量の荷物を積載した場合、例えば、欧州のレギュレーションＥＣＥ４８のように、乗員が前席に１人、後席に０人、トランクに車両の最大積載量（２００〜５００Ｋｇ）の荷物を積んで走行するような場合には、リアが大きく沈むため、フロントが浮き上がり、図５に×印で示すように、前輪位置の車高が基準位置よりも高くなってしまうことがある。このような場合に前記（数３）式でピッチ角を計算すると、計算上のピッチ角が真のピッチ角よりも絶対値で小さくなる。この値に基づいてヘッドランプの光軸調節を行なうと、光軸を下げる量が小さくなるため、ヘッドランプが上を向して前方車両や対向車に眩惑を与えるおそれがある。
【００２１】
そこで、図５に示すように、前輪位置Ｐｆにおける車高位置を、車高が高くなる方向に所定値だけ予め補正しておき、補正後の車高位置（前輪位置Ｐｆに×印で示す）と基準位置との距離、すなわち前輪位置Ｐｆにおける補正後の車高変化量仮想値（−β）を用いて下記（数４）式によってピッチ角θを演算する。
θ＝ｔａｎ-1〔（−β−ｈｒ）／ｗ〕…（数４）
上記のように前輪位置の車高位置が基準位置より高くなるのは、リアに大量の荷物を積載した場合であり、その時、後輪位置の車高変化量は非常に大きな値となる。したがって、後輪位置の車高変化量が所定値（例えば７０ｍｍ）以上となった場合には、上記のように前輪位置の車高位置が基準位置よりも高くなったと判断して、（数４）式に基づいてピッチ角θを演算する。βの値は、後輪位置が所定値（例えば７０ｍｍ）以上に低下するような、リアに大量の荷物を搭載した場合に一般に前輪位置が上昇する程度の値（車種によって異なる値）に設定する。なお、図５において、θ１は（数３）式で求めたピッチ角、θ２は（数４）式で求めたピッチ角を示す。
【００２２】
上記のように、後輪位置の車高変化量が所定値Ｒａ（例えば７０ｍｍ）未満の場合には、（数３）式を用いてピッチ角θを演算し、所定値Ｒａ以上の場合には（数４）式を用いてピッチ角θを演算することにより、後輪位置にのみを車高センサを設けるだけで、通常の乗車状態の場合でも、リアに大量の貨物を搭載した場合でも、常に正確なピッチ角を検出することが出来、それによってヘッドランプの光軸を適正に調節することが出来る。
【００２３】
図６は光軸制御の処理を示すフローチャートである。
図６において、ステップＳ１では、後輪位置に設けた車高センサ１１によって後輪位置の車高変化量ｈｒを検出する。
ステップＳ２では、後輪位置の車高変化量ｈｒが所定値Ｒａ以上か否かを判定する。ステップＳ２で“ＮＯ”（未満）の場合には、ステップＳ３で前輪位置の車高変化量仮想値をαとし、“ＹＥＳ”（以上）の場合にはステップＳ４で前輪位置の車高変化量仮想値を−βとする。
ステップＳ５では、上記のαまたは−βを用いて、前記（数３）式または（数４）式によってピッチ角を演算する。
ステップＳ６では、上記の演算したピッチ角に基づいてヘッドランプの光軸位置を演算し、ステップＳ７では、その光軸位置となるようにヘッドランプの角度を制御する。
【００２４】
（第２の実施の形態）
前記第１の実施の形態では、後輪位置にのみ車高センサを設置する場合を示したが、第２の実施の形態では前輪位置にのみ車高センサを設置する場合を説明する。なお、構成は前記図１において、車高センサ１１を前輪位置に設け、前輪位置Ｐｆの車高変化量ｈｆを検出する点のみが第１の実施の形態の構成と異なるだけであり、その他は同様である。
【００２５】
基本的な考え方は、第１の実施の形態と同様であり、前輪位置の車高変化量ｈｆに応じて後輪位置に車高変化量仮想値αと−βを設ければよい。すなわち、図７に示すように、前輪位置の車高変化量ｈｆが所定値（例えば７０ｍｍ）未満の場合には、後輪位置の車高変化量仮想値をαとして下記（数５）式を用いてピッチ角を演算し、所定値以上の場合には車高変化量仮想値を−βとして下記（数６）式を用いてピッチ角を演算する。
θ＝ｔａｎ-1〔（ｈｆ−α）／ｗ〕…（数５）
θ＝ｔａｎ-1〔（ｈｆ＋β）／ｗ〕…（数６）
なお、上記のピッチ角を用いてヘッドランプの光軸を調節する機能は、第１の実施の形態と同様である。
【００２６】
上記のように、前輪位置における車高検出値ｈｆのみを用いても、車高変化量の仮想値αおよび−βを設定することにより、正確なピッチ角を演算することができ、適正なヘッドランプの照射距離および範囲を確保できる。
【図面の簡単な説明】
【図１】本発明の一実施の形態における構成を示すブロック図。
【図２】前輪位置Ｐｆと後輪位置Ｐｒにおける基準位置、検出位置および車高変化量の関係を示す図。
【図３】実際の車両において前輪位置が沈んだ状態を示す図。
【図４】後輪位置の車高変化量を検出して車高変化量仮想値αを設けた状態を示す図。
【図５】後輪位置の車高変化量を検出して車高変化量仮想値αと−βを設けた状態を示す図。
【図６】光軸制御の処理を示すフローチャート。
【図７】前輪位置の車高変化量を検出して後輪位置に車高変化量仮想値αと−βを設けた状態を示す図。
【符号の説明】
１…モータ ２…位置センサ
３…モータ ４…位置センサ
５、６…制御回路 ７…コントローラ
８…イグニッションスイッチ ９…スモールランプスイッチ
１０…スモールランプ（車幅灯） １１…車高センサ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a device for calculating a pitch angle of a vehicle, that is, an angle of a vehicle in a front-rear direction with respect to a horizontal direction.
[0002]
[Prior art]
The pitch angle of the vehicle is a numerical value required by, for example, a device that automatically corrects the angle of the headlamp (so-called headlamp / auto-leveler). The pitch angle θ can be obtained by the following equation (1) based on the vehicle height hf at the front wheel position of the vehicle, the vehicle height hr at the rear wheel position, and the wheel base length w.
θ = tan −1 [(hf−hr) / w] (Equation 1)
The vehicle height hf at the front wheel position and the vehicle height hr at the rear wheel position are not the height values from the ground, but the vehicle height position (hereinafter referred to as the reference position) in the vehicle reference state (for example, empty state). (Hereinafter, hf and hr are referred to as a vehicle height change amount). Therefore, the pitch angle θ in the reference state of the vehicle is 0 degree.
As a sensor for detecting the vehicle height change amounts hf and hr, a vehicle height sensor that detects the suspension arm angle of each wheel and converts it to a vehicle height change amount is practically used.
[0003]
[Problems to be solved by the invention]
Using the vehicle height sensor as described above, the pitch angle can be obtained by performing the calculation as in the equation (1). However, it may be difficult to install a vehicle height sensor on models with a complex suspension structure such as a four-wheel drive vehicle, and the pitch angle is detected with as few vehicle height sensors as possible in order to reduce man-hours and costs. It is desirable to do.
[0004]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a pitch angle calculation device capable of calculating the pitch angle by detecting the amount of change in vehicle height on either side of the vehicle. And
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as described in the claims. That is, in the first aspect of the invention, the vehicle height detecting means is provided at any one of the two positions Pf and Pr in the vehicle front-rear direction separated by a predetermined distance w to detect the vehicle height change amount, and the vehicle height A predetermined vehicle height change amount virtual value is set as the vehicle height change amount on the side where the detection means is not installed, and the vehicle is based on the actual vehicle height change detection value, the vehicle height change virtual value, and the distance w. The vehicle height change amount actually detected by the vehicle height detecting means is less than a predetermined value in a direction in which the vehicle body sinks when the vehicle height value in the empty state is used as a reference position . In this case, the vehicle height change virtual value is set to a value when the vehicle height sinks with reference to the empty vehicle state. If the vehicle height is greater than the predetermined value, the vehicle height change virtual value is set to the vehicle height with reference to the empty vehicle state. Is configured to set the value to the raised state ,
When vehicle height detection means for detecting the vehicle height change amount at the rear wheel position is provided as Pr, the change amount from the reference position toward the lower vehicle height is set to be positive, and the change amount toward the higher one is reversed. When the vehicle height change amount hr at the rear wheel position actually detected by the vehicle height detection means is less than a predetermined value Ra, the vehicle height change amount virtual value at the front wheel position is set to a positive value. If the predetermined value α is greater than or equal to the predetermined value Ra, the pitch angle θ is calculated based on the following first and second expressions as a negative predetermined value −β ,
When vehicle height detection means for detecting the vehicle height change amount at the front wheel position is provided as Pf, the change amount from the reference position to the vehicle height lowering is positive, and conversely the change amount to the higher vehicle height is If the value of the vehicle height change amount hf at the front wheel position actually detected by the vehicle height detection means is less than a predetermined value Ra when negative, the vehicle height change amount virtual value at the rear wheel position is set to a positive predetermined value. When the value α is greater than or equal to the predetermined value Ra, the negative predetermined value −β is set, and the pitch angle θ is calculated based on the following third and fourth expressions.
θ = tan −1 [(α−hr) / w] where hr <Ra ( 1 )
θ = tan −1 [(−β−hr) / w] where hr ≧ Ra (2nd formula)
θ = tan −1 [(hf−α) / w] where hf <Ra (Equation 3)
θ = tan −1 [(hf + β) / w] where hf ≧ Ra ( 4th formula )
By the structure described above SL, in structure in which a vehicle height detecting means to only one of the front and rear, even if in case of a normal riding position front also rear also sink than unladen condition, with large amounts of cargo to the rear Even when the rear sinks and the front is lifted, the accurate pitch angle can always be detected.
[0007]
【The invention's effect】
According to the present invention, an accurate pitch angle can be calculated only by providing a vehicle height detection means on either the front or rear of the vehicle even when the pitch angle changes greatly according to the weight of the passenger or cargo. It is possible to obtain the effect that the cost of the apparatus can be reduced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is applied to a headlamp auto levelizer will be described. The headlamp auto-leveler is a device that automatically adjusts the angle of the headlamp according to the pitch angle, and controls it so that appropriate illumination is always possible. The present invention is not limited to the headlamp / auto-leveler, but can be applied to all devices that perform control based on the pitch angle.
[0009]
(First embodiment)
FIG. 1 is a block diagram showing a configuration in the present embodiment. In this embodiment, the vehicle height change amount hr at the rear wheel position of the vehicle is detected, the pitch angle θ is calculated, and the optical axis of the headlamp is adjusted.
In FIG. 1, a
[0010]
The control circuit 5 drives and controls the
[0011]
The ignition switch 8 is closed when the ignition key is set to the ON position, and supplies the battery power BAT to the
[0012]
The vehicle height sensor 11 is attached to, for example, the suspension arm of the right rear wheel, detects the arm angle, and detects the vehicle height change amount hr at the right rear wheel position. That is, only one vehicle height sensor is used, and only the vehicle height change amount hr in the rear wheel is detected.
[0013]
The
[0014]
FIG. 2 is a diagram showing the relationship among the reference position, the detection position, and the vehicle height change amount at the front wheel position Pf and the rear wheel position Pr. The white circles at the front wheel position Pf and the rear wheel position Pr both indicate the vehicle height position in the reference state of the vehicle, that is, the reference position. W is the wheelbase length.
[0015]
As described above, the pitch angle θ is zero when the vehicle is in the empty reference state. When the vehicle height at the front and rear wheel positions changes from the reference position in accordance with the passengers and the weight of the cargo, a pitch angle corresponding to the change amount is generated. A black circle at the rear wheel position Pr indicates a detection position, and a distance between the detection position and the reference position is a change amount of the vehicle height from the reference position, that is, a vehicle height change amount hr at the rear wheel position Pr. To detect this value.
[0016]
In this specification, the amount of change from the reference position to the lower vehicle height is positive, and the amount of change to the higher vehicle height is negative. Therefore, according to the formula (1), the pitch angle θ when the front part of the vehicle sinks or the rear part of the vehicle rises becomes positive, and conversely, when the front part of the vehicle rises or the rear part of the vehicle sinks. The pitch angle θ is negative. The pitch angle θ in the case of FIG. 2 is as shown, and the value is negative.
[0017]
In the first embodiment, only the vehicle height sensor 11 that detects the amount of change in vehicle height at the rear wheel position Pr is installed, and no vehicle height sensor is installed at the front wheel position Pf. Therefore, assuming that the vehicle height of the front wheel position Pf is the reference position (the amount of change is zero), hf = 0, and therefore, the pitch angle θ ′ of the vehicle is expressed by the following equation (Equation 2).
θ ′ = tan −1 [(0−hr) / w] (Equation 2)
However, in general, when a crew member or cargo is loaded, the actual front wheel position Pf (indicated by a black circle at the front wheel position Pf) becomes lower than the reference position (indicated by a white circle at the front wheel position) as shown in FIG. Therefore, since hf actually has a positive value, the true pitch angle θ ″ is smaller in absolute value than the calculated pitch angle θ ′ (Equation 2). Therefore, the calculated pitch angle θ ′ If the optical axis adjustment of the headlamp is performed based on the above, the optical axis is lowered more than necessary, and the headlamp is directed downwardly and the front irradiation distance is shortened.
[0018]
Therefore, as shown in FIG. 4, the vehicle height position at the front wheel position Pf is corrected in advance by a predetermined value in the direction in which the vehicle height decreases, and the corrected vehicle height position (indicated by a black circle at the front wheel position Pf) The pitch angle θ is calculated by the following formula (Equation 3) using the corrected vehicle height change amount virtual value α at the distance from the reference position, that is, the front wheel position Pf.
θ = tan −1 [(α−hr) / w] (Equation 3)
Note that the value of the vehicle height variation virtual value α is set to a value (a value that differs depending on the vehicle type) that is generally expected to decrease the front wheel position for passengers and luggage.
[0019]
As described above, the optical axis position of the headlamp is determined according to the pitch angle θ calculated based on the detected value hr of the vehicle height change amount at the rear wheel position and the virtual value α of the vehicle height change amount at the front wheel position. By performing the optical axis control, it is possible to calculate an accurate pitch angle not only when the vehicle height at the rear wheel position but also the vehicle height at the front wheel position is lowered according to the weight of the crew and cargo. Appropriate headlamp irradiation distance and range can be secured.
[0020]
By the way, when a large amount of luggage is loaded on the rear trunk, for example, as in the European regulation ECE48, there are one passenger in the front seat, zero in the rear seat, and the maximum loading capacity of the vehicle in the trunk (200-500 kg) When traveling with a large amount of baggage, the rear sinks greatly and the front is lifted, and the vehicle height at the front wheel position may become higher than the reference position, as indicated by a cross in FIG. . In such a case, if the pitch angle is calculated by the equation (3), the calculated pitch angle becomes smaller in absolute value than the true pitch angle. If the optical axis adjustment of the headlamp is performed based on this value, the amount of lowering the optical axis becomes small, so that the headlamp may face upward and dazzle the vehicle ahead and the oncoming vehicle.
[0021]
Therefore, as shown in FIG. 5, the vehicle height position at the front wheel position Pf is corrected in advance by a predetermined value in the direction in which the vehicle height increases, and the corrected vehicle height position (indicated by the X in the front wheel position Pf). And the reference position, that is, the pitch angle θ is calculated by the following equation (4) using the corrected vehicle height variation virtual value (−β) at the front wheel position Pf.
θ = tan −1 [(−β−hr) / w] (Equation 4)
As described above, the vehicle height position at the front wheel position is higher than the reference position when a large amount of luggage is loaded on the rear. At that time, the amount of change in the vehicle height at the rear wheel position is a very large value. Therefore, when the amount of change in the vehicle height at the rear wheel position is equal to or greater than a predetermined value (for example, 70 mm), it is determined that the vehicle height position at the front wheel position is higher than the reference position as described above. ) To calculate the pitch angle θ. The value of β is set to a value that generally increases the front wheel position (a value that varies depending on the vehicle type) when a large amount of luggage is mounted on the rear, such that the rear wheel position drops to a predetermined value (for example, 70 mm) or more. . In FIG. 5, θ1 represents the pitch angle obtained by Equation (3), and θ2 represents the pitch angle obtained by Equation (4).
[0022]
As described above, when the amount of change in the vehicle height at the rear wheel position is less than a predetermined value Ra (for example, 70 mm), the pitch angle θ is calculated using the equation (3). By calculating the pitch angle θ using the equation (4), only by providing a vehicle height sensor only at the rear wheel position, even in a normal riding state or when a large amount of cargo is mounted on the rear, An accurate pitch angle can always be detected, whereby the optical axis of the headlamp can be adjusted appropriately.
[0023]
FIG. 6 is a flowchart showing the optical axis control process.
In FIG. 6, in step S1, a vehicle height change amount hr at the rear wheel position is detected by a vehicle height sensor 11 provided at the rear wheel position.
In step S2, it is determined whether or not the vehicle height change amount hr at the rear wheel position is greater than or equal to a predetermined value Ra. If "NO" (less than) in step S2, the vehicle height change amount virtual value of the front wheel position is set to α in step S3, and if "YES" (above), the vehicle height change amount of the front wheel position in step S4. Let the virtual value be -β.
In step S5, the pitch angle is calculated by the above formula (3) or (formula 4) using the above α or -β.
In step S6, the optical axis position of the headlamp is calculated based on the calculated pitch angle, and in step S7, the headlamp angle is controlled so as to be the optical axis position.
[0024]
(Second Embodiment)
Although the case where the vehicle height sensor is installed only at the rear wheel position has been described in the first embodiment, the case where the vehicle height sensor is installed only at the front wheel position will be described in the second embodiment. The configuration in FIG. 1 is different from the configuration of the first embodiment only in that the vehicle height sensor 11 is provided at the front wheel position and the vehicle height change amount hf at the front wheel position Pf is detected. It is the same.
[0025]
The basic concept is the same as in the first embodiment, and the vehicle height change amount virtual values α and −β may be provided at the rear wheel position in accordance with the vehicle height change amount hf at the front wheel position. That is, as shown in FIG. 7, when the vehicle height change amount hf at the front wheel position is less than a predetermined value (for example, 70 mm), the following equation (5) is used, where α is the vehicle height change amount at the rear wheel position. Is used to calculate the pitch angle. If the pitch angle is greater than or equal to a predetermined value, the vehicle height change amount virtual value is set to -β and the pitch angle is calculated using the following equation (6).
θ = tan −1 [(hf−α) / w] (Equation 5)
θ = tan −1 [(hf + β) / w] (Equation 6)
The function of adjusting the optical axis of the headlamp using the pitch angle is the same as in the first embodiment.
[0026]
As described above, even if only the vehicle height detection value hf at the front wheel position is used, the accurate pitch angle can be calculated by setting the virtual values α and −β of the vehicle height change amount, and the appropriate head The irradiation distance and range of the lamp can be secured.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration according to an embodiment of the present invention.
FIG. 2 is a diagram showing a relationship among a reference position, a detection position, and a vehicle height change amount at a front wheel position Pf and a rear wheel position Pr.
FIG. 3 is a diagram showing a state in which a front wheel position is sunk in an actual vehicle.
FIG. 4 is a diagram showing a state in which a vehicle height change amount virtual value α is provided by detecting a vehicle height change amount at a rear wheel position.
FIG. 5 is a diagram illustrating a state in which a vehicle height change amount at the rear wheel position is detected and vehicle height change amount virtual values α and −β are provided.
FIG. 6 is a flowchart showing optical axis control processing.
FIG. 7 is a diagram showing a state in which a vehicle height change amount α and −β are provided at a rear wheel position by detecting a vehicle height change amount at a front wheel position.
[Explanation of symbols]
DESCRIPTION OF
Claims (1)
前記ＰｆとＰｒの何れか一方において実際に検出した車高変化量の値が、空車状態の車高値を基準位置とした場合に車体が沈む方向で所定値未満の場合は、前記車高変化量仮想値を、空車状態を基準として車高が沈んだ状態の値とし、前記所定値以上の場合は、前記車高変化量仮想値を、空車状態を基準として車高が上がった状態の値に設定するように構成し、
前記Ｐｒとして後輪位置の車高変化量を検出する車高検出手段を設けた場合は、基準位置から車高が低くなる方への変化量を正とし、逆に高くなる方への変化量を負とした場合に、前記車高検出手段で実際に検出した後輪位置の車高変化量ｈｒの値が、所定値Ｒａ未満の場合は、前輪位置の車高変化量仮想値を正の所定値αとし、所定値Ｒａ以上の場合は負の所定値−βとして、下記の第１式、第２式に基づいてピッチ角θを演算し、
前記Ｐｆとして前輪位置の車高変化量を検出する車高検出手段を設けた場合は、基準位置から車高が低くなる方への変化量を正とし、逆に高くなる方への変化量を負とした場合に、前記車高検出手段で実際に検出した前輪位置の車高変化量ｈｆの値が、所定値Ｒａ未満の場合は、後輪位置の車高変化量仮想値を正の所定値αとし、所定値Ｒａ以上の場合は負の所定値−βとして、下記の第３式、第４式に基づいてピッチ角θを演算することを特徴とする車両のピッチ角演算装置。
θ＝ｔａｎ −１ 〔（α−ｈｒ）／ｗ〕 ただし、ｈｒ＜Ｒａ …第１式
θ＝ｔａｎ −１ 〔（−β−ｈｒ）／ｗ〕 ただし、ｈｒ≧Ｒａ …第２式
θ＝ｔａｎ −１ 〔（ｈｆ−α）／ｗ〕 ただし、ｈｆ＜Ｒａ …第３式
θ＝ｔａｎ −１ 〔（ｈｆ＋β）／ｗ〕 ただし、ｈｆ≧Ｒａ …第４式 A vehicle height detection means is provided at one of the two positions Pf and Pr in the vehicle longitudinal direction separated by a predetermined distance w to detect a vehicle height change amount, and the vehicle height detection means of the Pf and Pr is installed. A predetermined vehicle height change amount virtual value is set as the vehicle height change amount on the non-operating side, and the vehicle pitch angle is determined based on the actual vehicle height change detection value, the vehicle height change virtual value, and the distance w. A device for computing,
If the value of the vehicle height change actually detected in one of Pf and Pr is less than a predetermined value in the direction in which the vehicle body sinks when the vehicle height value in the empty state is used as a reference position , the vehicle height change amount The virtual value is a value in a state where the vehicle height is depressed with respect to the empty vehicle state, and when the vehicle height is equal to or greater than the predetermined value, the virtual value of the vehicle height change is changed to a value in a state in which the vehicle height is increased with reference to the empty vehicle state Configure to set up,
When vehicle height detection means for detecting the vehicle height change amount at the rear wheel position is provided as Pr, the change amount from the reference position toward the lower vehicle height is set to be positive, and the change amount toward the higher one is reversed. When the vehicle height change amount hr at the rear wheel position actually detected by the vehicle height detection means is less than a predetermined value Ra, the vehicle height change amount virtual value at the front wheel position is set to a positive value. If the predetermined value α is greater than or equal to the predetermined value Ra, the pitch angle θ is calculated based on the following first and second expressions as a negative predetermined value −β ,
When vehicle height detection means for detecting the vehicle height change amount at the front wheel position is provided as Pf, the change amount from the reference position to the vehicle height lowering is positive, and conversely the change amount to the higher vehicle height is If the value of the vehicle height change amount hf at the front wheel position actually detected by the vehicle height detection means is less than a predetermined value Ra when negative, the vehicle height change amount virtual value at the rear wheel position is set to a positive predetermined value. A pitch angle calculation device for a vehicle, wherein a pitch angle θ is calculated based on the following third and fourth formulas, with a value α and a negative predetermined value −β when the value is equal to or greater than a predetermined value Ra .
θ = tan −1 [(α−hr) / w] where hr <Ra ( 1 )
θ = tan −1 [(−β−hr) / w] where hr ≧ Ra (2nd formula)
θ = tan −1 [(hf−α) / w] where hf <Ra (Equation 3)
θ = tan −1 [(hf + β) / w] where hf ≧ Ra (fourth formula)
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| JP4499172B2 (en) * | 2008-12-12 | 2010-07-07 | 三菱電機株式会社 | Lighting device |
| CN108050992A (en) * | 2017-12-06 | 2018-05-18 | 中国十九冶集团有限公司 | The method for measuring building inclination |
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| JP4140125B2 (en) * | 1998-08-31 | 2008-08-27 | 株式会社デンソー | Automatic headlamp optical axis adjustment device for vehicles |
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