JP4101455B2 - Vehicle rollover prevention device - Google Patents

Description

【００３０】
または、より精度の高い演算式として、次式を用いてもよい。
【００３１】
【数２】

【００３２】
ステップ３では、平均ロール角度θ_aveが演算される。即ち、ステップ２で演算されるロール角度θは、車高センサ１６Ｌ，１６Ｒを介して車高Ｈ_L及びＨ_Rを検出した瞬間におけるロール角度であるため、例えば、路面の凹凸による細かい振動も検出してしまう。このため、数個〜数十個のロール角度θの移動平均を演算し、これを平均ロール角度θ_aveとすることで、誤動作の要因となる必要以上の感度を排除することができる。なお、ステップ３における処理が、移動平均演算手段に該当する。
【００３３】
ステップ４では、平均ロール角度θ_aveの変化率に基づいて、車両のロール角速度ωが演算される。なお、ステップ４における処理が、ロール角速度演算手段に該当する。
【００３４】
ステップ５では、平均ロール角度θ_aveの絶対値が、所定値θ₀より大きいか否かが判定される。ここで、所定値θ₀は、ロールが少ないときには処理を行なわないようにする閾値であって、例えば、車両が横転する可能性が極めて低い値に設定される。そして、平均ロール角度θ_aveの絶対値が所定値θ₀より大きければステップ６へと進み（Ｙｅｓ）、平均ロール角度θ_aveの絶対値が所定値θ₀以下であれば処理を終了する（Ｎｏ）。
【００３５】
ステップ６では、ロール角速度ωの絶対値が、所定値ω₀より大きいか否かが判定される。ここで、所定値ω₀は、停車中又は低速走行中であるか否かを判定する閾値であって、例えば、停車中又は低速走行中では採り得ない値に設定される。そして、ロール角速度ωの絶対値が所定値ω₀より大きければステップ７へと進み（Ｙｅｓ）、車両横転の危険性を判定するための所定値θ ₁ 〜θ ₃ の補正値Δθとして、０（補正なし）が設定される。一方、ロール角度ωの絶対値が所定値ω₀以下であればステップ８へと進み（Ｎｏ）、車両横転の危険性を判定するための所定値θ ₁ 〜θ ₃ の補正値Δθとして、所定値θ’が設定される。なお、ステップ６〜ステップ８における処理が、補正値設定手段に該当する。
【００３６】
ステップ９では、ロール角速度ωの絶対値が、ロール緊急度が大である領域を画定する所定値ω₂より大きいか否かが判定される。そして、ロール角速度ωの絶対値が所定値ω₂より大きければステップ１０へと進み（Ｙｅｓ）、ロール緊急度が大であると判定される。一方、ロール角速度ωの絶対値が所定値ω₂以下であればステップ１１へと進む（Ｎｏ）。
【００３７】
ステップ１１では、ロール角速度ωの絶対値が、ロール緊急度が小である領域を画定する所定値ω₁以上かつ所定値ω₂以下であるか否かが判定される。そして、ロール角速度ωの絶対値が所定値ω₁以上かつ所定値ω₂以下であればステップ１２へと進み（Ｙｅｓ）、ロール緊急度が中であると判定される。一方、ロール角速度ωの絶対値が所定値ω₁未満（ロール角速度ωの絶対値が所定値ω₂より大きい場合は、ステップ９で判定済み）であればステップ１３へと進み（Ｎｏ）、ロール緊急度が小であると判定される。
【００３８】
ロール緊急度が大であると判定されたステップ１４では、平均ロール角度θ_aveの絶対値が、所定値θ₃と補正値Δθとの加算値より大きいか否かが判定される。そして、平均ロール角度θ_aveの絶対値が所定値θ₃と補正値Δθとの加算値より大きければステップ１７へと進み（Ｙｅｓ）、平均ロール角度θ_aveの絶対値が所定値θ₃と補正値Δθとの加算値以下であれば処理を終了する（Ｎｏ）。ここで、補正値Δθを用いることで、停車中又は低速走行中のように、平均ロール角度θ _ave が大きいが車両横転の危険性が低い状態を処理対象から除外することができる。
【００３９】
ロール緊急度が中であると判定されたステップ１５では、平均ロール角度θ_aveの絶対値が、所定値θ₂と補正値Δθとの加算値より大きいか否かが判定される。そして、平均ロール角度θ_aveの絶対値が所定値θ₂と補正値Δθとの加算値より大きければステップ１７へと進み（Ｙｅｓ）、平均ロール角度θ_aveの絶対値が所定値θ₂と補正値Δθとの加算値以下であれば処理を終了する（Ｎｏ）。
【００４０】
ロール緊急度が小であると判定されたステップ１６では、平均ロール角度θ_{av e}の絶対値が、所定値θ₁と補正値Δθとの加算値より大きいか否かが判定される。そして、平均ロール角度θ_aveの絶対値が所定値θ₁と補正値Δθとの加算値より大きければステップ１７へと進み（Ｙｅｓ）、平均ロール角度θ_aveの絶対値が所定値θ₁と補正値Δθとの加算値以下であれば処理を終了する（Ｎｏ）。
【００４１】
なお、ステップ１４〜ステップ１６における処理が、危険性判定手段に該当する。
ステップ１７では、車両横転の危険性があると判定し、ロールインジケータ１８に付設された警告灯が点灯される。
ステップ１８では、車両横転の危険性があることを運転者に音声で報知すべく、警報器２２が作動される。なお、ステップ１７及びステップ１８において警告灯及び警報器２２を作動させる処理が、警告発生手段に該当する。
【００４２】
ステップ１９では、平均ロール角度θ_aveの絶対値が、ロール緊急度に応じた所定値θ₁，θ₂又はθ₃と増分Δθ’との加算値より大きいか否かが判定される。ここで、増分Δθ’は、車両横転の危険性を低下すべく減速制御を実行するか否かを判定するための補正値であって、例えば、正の値をとる所定値に設定される。そして、平均ロール角度θ _ave の絶対値が所定値θ ₁ ，θ ₂ 又はθ ₃ と増分Δθ’との加算値より大きければステップ２０へと進む一方（Ｙｅｓ）、平均ロール角度θ _ave の絶対値が所定値θ ₁ ，θ ₂ 又はθ ₃ と増分Δθ’との加算値以下であれば処理を終了する（Ｎｏ）。なお、増分Δθ’は、ロール緊急度に応じて変化させてもよい。
【００４３】
ステップ２０では、エンジンコントローラ２６又は／及びブレーキコントローラ２８に対して、燃料供給量減量指令又はブレーキ作動指令を伝達し、減速制御が行なわれる。なお、ステップ２０における処理が、車両減速手段，ブレーキ作動手段及び燃料低減手段に該当する。
以上説明したステップ１〜ステップ２０の処理によれば、所定のサンプリング間隔で検出された車高Ｈ_L及びＨ_Rに基づいて、車両のロール角度θが演算される。そして、数個〜数十個のロール角度θの移動平均が演算され、これが平均ロール角度θ_aveとされる。このため、例えば、路面の凹凸による細かい振動が検出されたときであっても、移動平均を演算することでこれが平滑化され、誤動作の要因となる必要以上の感度を排除することができる。
【００４４】
また、平均ロール角度θ_aveの絶対値が所定値θ₀より大きいときには、ロール角速度ωに応じた緊急度が判定される。ロール緊急度は、車両横転の危険性の大小を示す尺度であって、これにより、以後の判断処理を分けることで、横転危険性判断に係る精度を向上することができる。そして、各ロール緊急度毎に、平均ロール角度θ_aveの絶対値が所定値θ ₁ 〜θ ₃ と補正値Δθとの加算値より大であるか否かが判定され、その判定結果に応じて、ロールインジケータ１８に付設された警告灯及び警報器２２の制御が行なわれる。
【００４５】
従って、実際のロール角度が横転危険角度になる前に、運転者に対して警告が発せられることとなる。このため、運転者は、余裕をもって危険回避操作を行なうことができ、車両運行上の安全性を向上させることができる。
【００４６】
さらに、運転者に対して警告が発せられた場合であっても、平均ロール角度θ_aveの絶対値が所定値θ ₁ 〜θ ₃ と増分Δθ’との加算値より大きくなると、減速制御が実行される。このため、警告が発せられたにもかかわらず、運転者が危険回避操作を行なわなかったときであっても、減速を介してロール角度が減少し、車両横転の危険性を幾分でも低くすることができる。
【００４７】
なお、車両が停車中又は低速走行中であるか否かを判定するため、車両走行状態としてのロール角速度ωに代えて、車速ｖを用いてもよい。このようにすれば、車速ｖを介して車両の走行状態が直接的に把握できるため、判定精度を向上することができる。
図６は、コントロールユニット２４において実行される制御内容の他の実施例を示す。なお、図３及び図４に示す制御内容と同一のものについては、その部分の説明は省略するものとする。
【００４８】
ステップ２１では、所定時間ｔ［ｓ］経過後におけるロール角度（以下「推定ロール角度」という）θ’が演算される。ここで、所定時間ｔは、ロール角速度ωに応じた時間であって、例えば、ロール角速度ωが大きくなるにつれて小さくなるように設定される。推定ロール角度θ’は、平均ロール角度θ_ave，ロール角度の変化状態を表わすロール角速度ωに基づいて、θ’＝θ_ave＋ω×ｔという演算式から演算される。
【００４９】
また、ロール角速度ωの代わりに、ロール角度の変化状態を表わすロール角加速度α［rad／s²］を用い、θ’＝θ_ave＋（α×ｔ²）／２という演算式から演算してもよい。この場合、ロール角加速度αを用いることで、ロール角速度ωの変化率が把握でき、推定精度をより向上することができる。
なお、ステップ２１における処理が、ロール角度推定手段に該当する。
【００５０】
ステップ２２では、推定ロール角度θ'の絶対値が、所定値θ'₂より大きいか否かが判定される。ここで、所定値θ'₂は、ロール緊急度が大である領域を画定する閾値であって、例えば、車両横転の危険性が大となる値に設定される。そして、推定ロール角度θ'の絶対値が所定値θ'₂より大きければステップ２３へと進み（Ｙｅｓ）、ロール緊急度が大であると判定される。一方、推定ロール角度θ'の絶対値が所定値θ'₂以下であればステップ２４へと進む（Ｎｏ）。
【００５１】
ステップ２４では、推定ロール角度θ'の絶対値が、所定値θ'₁以上かつ所定値θ'₂以下であるか否かが判定される。ここで、所定値θ'₁は、ロール緊急度が小である領域を画定する閾値であって、例えば、車両横転の危険性が小である値に設定される。そして、推定ロール角度θ'の絶対値が所定値θ'₁以上かつ所定値θ'₂以下であればステップ２５へと進み（Ｙｅｓ）、ロール緊急度が中であると判定される。一方、推定ロール角度θ'の絶対値が所定値θ'₁未満（推定ロール角度θ'の絶対値が所定値θ'₂より大きい場合は、ステップ２２で判定済み）であればステップ２６へと進み（Ｎｏ）、ロール緊急度が小であると判定される。
【００５２】
なお、ステップ２２〜ステップ２６における処理が、緊急度判定手段に該当する。
ロール緊急度が大であると判定されたステップ２７では、現在の平均ロール角度θ_aveの絶対値が、所定値θ₃より大きいか否かが判定される。そして、現在の平均ロール角度θ_aveの絶対値が所定値θ₃より大きければステップ１７へと進み（Ｙｅｓ）、現在の平均ロール角度θ_aveの絶対値が所定値θ₃以下であれば処理を終了する（Ｎｏ）。
【００５３】
ロール緊急度が中であると判定されたステップ２８では、現在の平均ロール角度θ_aveの絶対値が、所定値θ₂より大きいか否かが判定される。そして、現在の平均ロール角度θ_aveの絶対値が所定値θ₂より大きければステップ１７へと進み（Ｙｅｓ）、現在の平均ロール角度θ_aveの絶対値が所定値θ₂以下であれば処理を終了する（Ｎｏ）。
【００５４】
ロール緊急度が小であると判定されたステップ２９では、現在の平均ロール角度θ_aveの絶対値が、所定値θ₁より大きいか否かが判定される。そして、現在のロール角度θ_aveの絶対値が所定値θ₁より大きければステップ１７へと進み（Ｙｅｓ）、現在のロール角度θ_aveの絶対値が所定値θ₁以下であれば処理を終了する（Ｎｏ）。
【００５５】
なお、ステップ２７〜ステップ２９における処理が、危険性判定手段に該当する。
以上説明したステップ２１〜ステップ２９の処理によれば、現在における平均ロール角度θ_ave並びにロール角速度ω若しくはロール角加速度αに基づいて、所定時間ｔ経過後の推定ロール角度θ’が演算される。そして、演算された推定ロール角度θ’に基づいて、ロール緊急度の大，中又は小が判定される。このため、先の実施形態に比べて、ロール緊急度の判定精度が向上し、より適切な時点で運転者に対して警告を発することができるようになる。また、先の実施形態と同様に、ロール角速度ωに応じた補正値Δθを設定し、ステップ２７〜ステップ２９において、現在の平均ロール角度θ_aveの絶対値が、所定値θ_1,2,3と補正値Δθとの加算値より大きいか否かを判定するようにしてもよい。
【００５６】
さらに、ステップ２７〜ステップ２９において車両横転の危険性を判定する際に、現在の平均ロール角度θ_aveに代えて、ステップ２１において演算された推定ロール角度θ’を用いてもよい。この場合、所定時間経過後の推定ロール角度θ’に基づいて車両横転の危険性が判定されるため、判定精度を一層向上することができる。ここで、推定ロール角度θ’に基づいて車両横転の危険性を判定する処理が、危険性判定手段に該当する。
【００５７】
なお、車高センサは、前軸における車両左右の車高を検出するようにしてもよい。この場合、車両のロールは操舵輪が連結される前軸から開始されるので、ロール状態の予測がより早く行なわれる。そして、運転者に対する警告が余裕をもって行なわれることで、安全性をより向上させることができる。
また、車両横転の危険性が大であると判定されたときには、図７に示すように、車両の左右に装着された補助輪３０Ｌ，３０Ｒ（ロール角度制限手段）を作動し、ロール角度θが限界値以下になるようにしてもよい。
【００５８】
【発明の効果】
以上説明したように、請求項１記載の発明によれば、運転者に対する警告は、車両のロール状態の予測に基づいて早期に発せられるため、危険回避操作を開始するまでの時間的余裕が確保され、車両運行上の安全性を向上させることができる。また、例えば、路面の凹凸による細かい振動を検出したとしても、移動平均を演算することでこれが平滑化されるため、不適切な警告が発せられることを防止できる。
【００５９】
請求項２記載の発明によれば、ロール角度が大ききなるにつれて所定時間を小さくすることができる。
【００６０】
請求項３記載の発明によれば、ロール角度又はその移動平均の絶対値が所定値と補正値との加算値より大きいときに、車両横転の危険性ありと判定することができる。
【００６１】
請求項４記載の発明によれば、車両の減速によりロール角度が小さくなるため、運転者による危険回避操作が遅れたとしても、車両横転の危険性を低減することができる。
請求項５記載の発明によれば、例えば、ブレーキコントローラ又は／及びエンジンコントローラに制御指令を伝達するだけで、車両を減速することができ、制御内容が複雑になることを防止できる。
【図面の簡単な説明】
【図１】本発明に係るロールオーバ防止装置をトラクタに適用した構成図
【図２】コントロールユニットにより実現される機能の説明図
【図３】制御内容の一例を示すフローチャート
【図４】制御内容の一例を示すフローチャート
【図５】ロール角度の演算方法を示す説明図
【図６】制御内容の他の一例を示すフローチャート
【図７】ロール角度を限界値以下にする補助輪の説明図
【符号の説明】
１６Ｌ，１６Ｒ 車高センサ
１８ ロールインジケータ
２２ 警報器
２４ コントロールユニット
２４ａ ロール角度演算部
２４ｂ ロール角速度演算部
２４ｃ ロール緊急度判定部
２４ｄ 横転危険性判定部
２４ｅ インジケータ制御部
２４ｆ 警報器制御部
２４ｇ 減速制御部
２６ エンジンコントローラ
２８ ブレーキコントローラ [0001]
BACKGROUND OF THE INVENTION
  The present inventionIt is related with the technique which warns early of the danger of the vehicle and improves the safety | security on vehicle operation.
[0002]
[Prior art]
If the vehicle turns sharply or enters the corner at an overspeed, the vehicle may roll excessively and roll over. Further, in a vehicle that transports a load such as a truck, the center of gravity is increased by loading the load, so that the roll angle becomes larger than other vehicles, and the risk of rollover increases.
[0003]
As an apparatus for informing the driver of the roll angle of the vehicle body, for example, an automotive tilt display device (hereinafter referred to as “tilt display device”) disclosed in Japanese Patent Laid-Open No. 5-96985 is known. In such a tilt display device, the tilt angle in the front-rear direction and the left-right direction of the vehicle is detected, the tilt state of the vehicle is displayed by a picture or the like, and an alarm sound is emitted when the tilt angle exceeds a predetermined value. For this reason, the driver can grasp the tilt state of the vehicle body at a glance, and can prevent the vehicle from overturning.
[0004]
[Problems to be solved by the invention]
However, in the conventional tilt display device, the tilt angle detection accuracy is low, the tilt state display and the alarm sound generation control are not always properly performed, and there is a risk of vehicle rollover. Further, since the display of the tilt state and the control of the generation of the warning sound are performed based on the current tilt angle of the vehicle, there is still a risk of the vehicle overturning when the driver's response is delayed.
[0005]
  Therefore, the present invention has the above conventional problems.In view of the rolling state of the vehicleThe purpose is to provide a rollover prevention device that secures time for risk avoidance operation and improves safety in vehicle operation by warning the risk of vehicle rollover early based on the prediction result of And
[0006]
[Means for Solving the Problems]
  Therefore, in the invention according to claim 1,Vehicle height detection means for detecting the vehicle height at the left and right of the vehicle, roll angle calculation means for calculating the roll angle of the vehicle based on the detected vehicle height, and moving average for calculating the moving average of the calculated roll angle Calculation means, roll angular velocity calculation means for calculating the roll angular velocity of the vehicle based on the calculated rate of change of the moving average of the roll angle, moving average and roll angular velocity of the calculated roll angleA roll angle estimating means for estimating the roll angle of the vehicle after a predetermined time,By comparing the absolute value of the estimated roll angle with a first threshold value defining a region where the roll urgency level is large and a second threshold value defining a region where the roll urgency level is small, As a measure of danger, urgency level judgment means for judging whether the urgency level is “large”, “medium” or “small”, and the absolute value of the moving average of the calculated roll angleOr the absolute value of the estimated roll angle isA predetermined value corresponding to the urgency determined by the urgency determination meansA risk determining means for determining that there is a risk of vehicle rollover when larger, and a warning generating means for issuing a warning to the driver when the risk determining means determines that there is a risk of vehicle rollover And a vehicle rollover prevention device.
[0010]
  According to such a configuration, the current roll angle andRoll angular velocityBased on the above, the roll angle of the vehicle after a predetermined time has elapsed is estimated. And to the estimated roll angleThe degree of urgency corresponding is determined, and the calculated absolute value of the moving average of the roll angle or the absolute value of the estimated roll angle corresponds to the degree of urgency.When larger than the predetermined value, it is determined that there is a risk of vehicle rollover, and a warning is issued to the driver. For this reason, the warning for the driver is issued early based on the directly predicted roll state of the vehicle, and a time margin until the danger avoidance operation is started is ensured.At this time, the roll angle is calculated based on the vehicle height at the left and right of the vehicle, and the moving average of the roll angle is calculated. For this reason, for example, even if fine vibration due to road surface unevenness is detected, the moving average is smoothed by calculating the moving average, and an inappropriate warning is prevented.
[0012]
  Claim 2In the described invention, the predetermined time is set so as to decrease as the roll angular velocity increases.
  According to this configuration, the predetermined time decreases as the roll angular velocity increases.
[0015]
  Claim 3In the described invention, it is provided with a correction value setting means for setting a correction value for correcting the predetermined value based on the absolute value of the roll angular velocity, and the risk determination means includes:Absolute value of moving average of calculated roll angleAlternatively, when the estimated absolute value of the roll angle is larger than the sum of the predetermined value and the correction value, it is determined that there is a risk of vehicle rollover.
  According to such a configuration,The absolute value of the moving average of the roll angle orWhen the absolute value of the roll angle is larger than the sum of the predetermined value and the correction value, it is determined that there is a risk of vehicle rollover.
[0016]
  Claim 4The described invention is characterized by comprising vehicle deceleration means for decelerating the vehicle when it is determined by the risk determination means that there is a risk of vehicle rollover.
  According to such a configuration, when it is determined that there is a risk of vehicle rollover, the vehicle is decelerated, so that the centrifugal force acting on the vehicle is reduced and the roll angle is reduced. For this reason, even if the risk avoidance operation by the driver is delayed, the risk of vehicle rollover is reduced.
[0017]
  Claim 5In the described invention, the vehicle deceleration means is at least one of a brake actuation means for actuating a brake of the vehicle and a fuel reduction means for reducing fuel supplied to the internal combustion engine.
  According to such a configuration, the vehicle is decelerated by operating the brake of the vehicle or reducing the fuel supplied to the internal combustion engine. For this reason, for example, the vehicle can be decelerated only by transmitting a control command to the brake controller or / and the engine controller, and the control contents are prevented from becoming complicated.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an embodiment in which a rollover prevention device (hereinafter referred to as “rollover prevention device”) according to the present invention is applied to a semi-tractor (hereinafter referred to as “tractor”).
[0020]
The left and right side frames 10L, 10R and the rear shaft 12 are connected to each other by a suspension mechanism 14 using a leaf spring. In the vicinity of the left and right side frames 10L, 10R, the vehicle height H on the left and right sides of the vehicle is determined via the distance (interval) between the side frames 10L, 10R and the rear shaft 12._LAnd H_RVehicle height sensors 16L and 16R (vehicle height detection means) are provided. Further, a roll indicator 18 that displays the roll state of the vehicle in a pictorial diagram, an alarm timing selection switch 20, and an alarm device 22 (alarm generating means) such as a buzzer are disposed in the vicinity of the driver's seat.
[0021]
As shown in the figure, a roll indicator 18 is provided with a pointer portion 18b representing a roll state of the vehicle in an annular zone 18a so as to be swingable. Below the zone 18a, a danger zone 18c indicating that the roll angle becomes excessive and there is a risk of vehicle rollover is displayed in red. Further, the roll indicator 18 is provided with a warning light (warning generating means) that warns the driver that there is a risk of vehicle rollover. The alarm timing selection switch 20 is a switch for setting a timing at which an alarm should be output according to the driver's preference. As shown in the figure, the switch member 20a is rotated to advance A and normal B early. And late C can be selected. That is, when the normal B is selected, a roll angle that is generally considered dangerous for the vehicle is selected as the alarm generation roll angle. On the other hand, when early A or late C is selected, a roll angle larger or smaller than a roll angle that is generally considered dangerous for the vehicle is selected as the alarm generation roll angle.
[0022]
  The outputs of the vehicle height sensors 16L and 16R and the alarm timing selection switch 20 are input to an electronic control unit (hereinafter referred to as “control unit”) 24 incorporating a microcomputer, respectively. Then, processing described later is executed based on the input signal, and the roll indicator 18 andAlarm 22The drive control is performed. Further, when the roll angle of the vehicle becomes excessive, a control command is transmitted to the engine controller 26 and the brake controller 28 in order to reduce the turning speed and reduce the roll angle by reducing the engine rotation speed.
[0023]
  The control unit 24Roll angle calculation means, moving average calculation means, roll angular velocity calculation means, roll angle estimation means, urgency determination means, risk determination means,The correction value setting means, the vehicle deceleration means, the brake operation means, and the fuel reduction means are realized by software.
[0024]
FIG. 2 shows a functional configuration of the control unit 24.
The control unit 24 includes a roll angle calculation unit 24a, a roll angular velocity calculation unit 24b, a roll emergency level determination unit 24c, a rollover risk determination unit 24d, an indicator control unit 24e, an alarm control unit 24f, and deceleration control. Part 24g.
[0025]
In the roll angle calculation unit 24a, the current roll angle θ [rad] is calculated based on signals from the vehicle height sensors 16L and 16R. The roll angular velocity calculation unit 24b calculates the current roll angular velocity ω [rad / s] based on the rate of change of the roll angle θ. The roll urgency determination unit 24c determines the roll urgency based on the roll angle θ and the roll angular velocity ω. Here, the “roll urgency” is a scale indicating the magnitude of the risk of vehicle rollover, and in this embodiment, at least three levels of high urgency, medium urgency, and low urgency are determined. . The rollover risk determination unit 24d determines whether or not there is a risk that the vehicle rolls over based on the roll urgency and the roll angle θ. In the indicator control unit 24e, the roll indicator 18 is controlled based on the determination result of the roll angle θ and the rollover risk. In the alarm device control unit 24f, the alarm device 22 is controlled based on the determination result of the risk of rollover. The deceleration control unit 24g reduces the fuel supply amount via the engine controller 26 and operates the brake via the brake controller 28 to reduce the vehicle speed based on the rollover risk determination result. And when a vehicle speed falls, turning speed falls and roll angle (theta) becomes small, and the danger of vehicle rollover can be reduced.
[0026]
3 and 4 show an embodiment of control contents executed in the control unit 24. FIG. Such control is repeatedly executed every predetermined time.
In step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), the vehicle height H on the left and right sides of the vehicle is passed through the vehicle height sensors 16L and 16R at predetermined sampling intervals (for example, several msec to several hundred msec)._LAnd H_RIs detected.
[0027]
In step 2, the detected vehicle height H_LAnd H_RBased on the above, the current roll angle θ is calculated. When the vehicle makes a left turn, as shown in FIG._LIs the vehicle height H on the right side of the vehicle_RLarger than (H_L> H_R). Here, when the mounting interval between the vehicle height sensors 16L and 16R is L, the roll angle θ of the vehicle is θ≈tan.^-1((H_L-H_R) / L). Further, the roll angle θ calculated here is a relative angle indicating the inclination of the vehicle with respect to the rear axle. Note that the processing in step 2 corresponds to roll angle calculation means.
[0028]
Here, the roll angle θ of the vehicle may be calculated by the following calculation formula.
[0029]
[Expression 1]

[0030]
Alternatively, the following expression may be used as a more accurate arithmetic expression.
[0031]
[Expression 2]

[0032]
  In step 3, the average roll angle θ_aveIs calculated. That is, the roll angle θ calculated in step 2 is determined by the vehicle height H via the vehicle height sensors 16L and 16R._LAnd H_RFor example, fine vibrations due to road surface irregularities are also detected. For this reason, a moving average of several to several tens of roll angles θ is calculated, and this is calculated as an average roll angle θ._aveBy doing so, it is possible to eliminate unnecessarily high sensitivity that causes malfunction. Note that the processing in step 3 is performed by the moving average calculation means.Applicable.
[0033]
  In step 4, the average roll angle θ_aveThe roll angular velocity ω of the vehicle is calculated based on the rate of change of the vehicle.Note that the processing in step 4 corresponds to roll angular velocity calculation means.
[0034]
In step 5, the average roll angle θ_aveIs the predetermined value θ₀It is determined whether or not it is larger. Where the predetermined value θ₀Is a threshold value that prevents the processing from being performed when the number of rolls is small, and is set, for example, to a value that is extremely unlikely to cause the vehicle to roll over. And the average roll angle θ_aveThe absolute value of₀If larger, proceed to Step 6 (Yes), and average roll angle θ_aveThe absolute value of₀If it is below, the process is terminated (No).
[0035]
  In step 6, the absolute value of the roll angular velocity ω is set to a predetermined value ω.₀It is determined whether or not it is larger. Where the predetermined value ω₀Is a threshold for determining whether the vehicle is stopped or traveling at a low speed, for example,While stopped or traveling at low speedIs set to a value that cannot be taken. The absolute value of the roll angular velocity ω is a predetermined value ω₀If it is larger, the process proceeds to Step 7 (Yes) to determine the risk of vehicle rollover.Predetermined value θ ₁ ~ Θ _Three Is set to 0 (no correction). On the other hand, the absolute value of the roll angle ω is a predetermined value ω₀If it is below, the process proceeds to Step 8 (No) to determine the risk of vehicle rollover.Predetermined value θ ₁ ~ Θ _Three As the correction value Δθ, a predetermined value θ ′ is set. Step 6~In step 8Processing is correction value setting meansIt corresponds to.
[0036]
  In step 9, the absolute value of the roll angular velocity ω isDefine areas where roll urgency is highPredetermined value ω₂Whether or notDetermined. AndThe absolute value of the roll angular velocity ω is the predetermined value ω₂If it is larger, the process proceeds to Step 10 (Yes), and it is determined that the roll urgency is large. On the other hand, the absolute value of the roll angular velocity ω is a predetermined value ω.₂If it is below, the process proceeds to Step 11 (No).
[0037]
  In step 11, the absolute value of the roll angular velocity ω isDefine areas where roll urgency is lowPredetermined value ω₁And the predetermined value ω₂Whether or notDetermined. AndThe absolute value of the roll angular velocity ω is the predetermined value ω₁And the predetermined value ω₂If it is below, the process proceeds to Step 12 (Yes), and it is determined that the roll urgency is medium. On the other hand, the absolute value of the roll angular velocity ω is a predetermined value ω.₁(The absolute value of the roll angular velocity ω is a predetermined value ω₂If it is larger, the process proceeds to Step 13 (No) if it has been determined in Step 9 (No), and it is determined that the roll urgency is small.
[0038]
  Roll urgencyIs determined to be large, step 14 determines that the average roll angle θ_aveIs the predetermined value θ_ThreeIs greater than the sum of the correction value Δθ andDetermined. AndAverage roll angle θ_aveThe absolute value of_ThreeAnd the correction value Δθ is greater than the added value, the process proceeds to step 17 (Yes), and the average roll angle θ_aveThe absolute value of_ThreeAnd the correction value Δθ are equal to or less than the addition value, the process is terminated (No).Here, the average roll angle θ can be obtained by using the correction value Δθ, such as when the vehicle is stopped or traveling at a low speed. _ave However, a state where the risk of vehicle rollover is low can be excluded from the processing target.
[0039]
In step 15 where the roll urgency is determined to be medium, the average roll angle θ_aveIs the predetermined value θ₂It is determined whether or not the sum is greater than the sum of the correction value Δθ. And the average roll angle θ_aveThe absolute value of₂And the correction value Δθ is greater than the added value, the process proceeds to step 17 (Yes), and the average roll angle θ_aveThe absolute value of₂And the correction value Δθ are equal to or less than the addition value, the process is terminated (No).
[0040]
In step 16 in which the roll urgency is determined to be small, the average roll angle θ_{av e}Is the predetermined value θ₁It is determined whether or not the sum is greater than the sum of the correction value Δθ. And the average roll angle θ_aveThe absolute value of₁And the correction value Δθ is greater than the added value, the process proceeds to step 17 (Yes), and the average roll angle θ_aveThe absolute value of₁And the correction value Δθ are equal to or less than the addition value, the process is terminated (No).
[0041]
  In addition, the process in step 14-step 16 corresponds to a danger determination means.
  In step 17, it is determined that there is a risk of vehicle rollover, and a warning lamp attached to the roll indicator 18 is turned on.
  In step 18, the alarm device 22 is activated to notify the driver by voice that there is a risk of vehicle rollover. In addition, the process which operates a warning lamp and the alarm device 22 in step 17 and step 18 corresponds to a warning generation means.
[0042]
  In step 19, the average roll angle θ_aveIs the predetermined value θ according to the roll urgency₁, Θ₂Or θ_ThreeIt is determined whether or not the sum is greater than the sum of the increment Δθ ′. Here, the increment Δθ ′ is a correction value for determining whether or not the deceleration control is executed in order to reduce the risk of vehicle rollover, and is set to a predetermined value that takes a positive value, for example.And the average roll angle θ _ave The absolute value of ₁ , Θ ₂ Or θ _Three And the increment Δθ ′ is greater than the added value, the process proceeds to step 20 (Yes), while the average roll angle θ _ave The absolute value of ₁ , Θ ₂ Or θ _Three And the process ends (No).Note that the increment Δθ ′ may be changed according to the roll urgency.
[0043]
  In step 20, a fuel supply amount reduction command or a brake operation command is transmitted to the engine controller 26 and / or the brake controller 28, and deceleration control is performed. Note that the processing in step 20 corresponds to vehicle deceleration means, brake actuation means, and fuel reduction means.
  According to the processing of step 1 to step 20 described above, the vehicle height H detected at a predetermined sampling interval._LAnd H_RBased on the above, the roll angle θ of the vehicle is calculated. Then, a moving average of several to several tens of roll angles θ is calculated, and this is the average roll angle θ._aveIt is said. For this reason, for example, even when fine vibration due to road surface unevenness is detected,moving averageThis can be smoothed to eliminate unnecessary sensitivity that causes malfunction.
[0044]
  Also, average roll angle θ_aveThe absolute value of₀When larger, the degree of urgency according to the roll angular velocity ω is determined. The roll urgency level is a scale indicating the magnitude of the risk of vehicle rollover. Accordingly, the accuracy of rollover risk determination can be improved by dividing subsequent determination processing. And for each roll urgency, the average roll angle θ_aveThe absolute value ofPredetermined value θ ₁ ~ Θ _Three Greater than the sum of the correction value and ΔθIt is determined whether or not the warning light and the alarm device 22 attached to the roll indicator 18 are controlled according to the determination result.
[0045]
  Therefore, actuallyA warning is issued to the driver before the roll angle becomes the rollover danger angle. For this reason, the driver can perform the danger avoidance operation with a margin, and can improve the safety in vehicle operation.
[0046]
  Furthermore, even when a warning is issued to the driver, the average roll angle θ_aveThe absolute value ofPredetermined value θ ₁ ~ Θ _Three And increment Δθ 'When it becomes larger, deceleration control is executed. For this reason, even when a warning is issued, even when the driver does not perform the danger avoidance operation, the roll angle is reduced through deceleration, and the risk of vehicle rollover is somewhat reduced. be able to.
[0047]
In order to determine whether the vehicle is stopped or traveling at a low speed, the vehicle speed v may be used instead of the roll angular velocity ω as the vehicle traveling state. In this way, since the traveling state of the vehicle can be directly grasped via the vehicle speed v, the determination accuracy can be improved.
FIG. 6 shows another embodiment of the control content executed in the control unit 24. In addition, about the same thing as the control content shown in FIG.3 and FIG.4, the description of the part shall be abbreviate | omitted.
[0048]
  Step 21Then, the roll angle (hereinafter referred to as “estimated roll angle”) θ ′ after the elapse of the predetermined time t [s] is calculated. Here, the predetermined time t is a time corresponding to the roll angular velocity ω, and is set to decrease as the roll angular velocity ω increases, for example. The estimated roll angle θ ′ is the average roll angle θ_ave,Roll angle change stateΘ ′ = θ based on the roll angular velocity ω representing_aveIt is calculated from an arithmetic expression of + ω × t.
[0049]
  Also, instead of the roll angular velocity ω,Roll angle change stateRoll angular acceleration α [rad / s²], Θ ′ = θ_ave+ (Α × t²) / 2. in this case,Roll angular acceleration αBy usingRoll angular velocity ωThe rate of change can be grasped, and the estimation accuracy can be further improved.
  The process in step 21 is performed by the roll angle estimation means.Applicable.
[0050]
In step 22, the absolute value of the estimated roll angle θ ′ is a predetermined value θ ′.₂It is determined whether or not it is larger. Here, the predetermined value θ ′₂Is a threshold value that defines an area where the degree of roll urgency is high, and is set to a value that increases the risk of vehicle rollover, for example. Then, the absolute value of the estimated roll angle θ ′ is a predetermined value θ ′.₂If it is larger, the process proceeds to step 23 (Yes), and it is determined that the roll urgency is large. On the other hand, the absolute value of the estimated roll angle θ ′ is a predetermined value θ ′.₂If it is below, the process proceeds to Step 24 (No).
[0051]
In step 24, the absolute value of the estimated roll angle θ ′ is a predetermined value θ ′.₁And the predetermined value θ ′₂It is determined whether or not: Here, the predetermined value θ ′₁Is a threshold value that defines an area where the roll urgency is small, and is set to a value where the risk of vehicle rollover is small, for example. Then, the absolute value of the estimated roll angle θ ′ is a predetermined value θ ′.₁And the predetermined value θ ′₂If it is below, it will progress to step 25 (Yes) and it will be determined that the roll urgency level is medium. On the other hand, the absolute value of the estimated roll angle θ ′ is a predetermined value θ ′.₁(The absolute value of the estimated roll angle θ ′ is a predetermined value θ ′₂If it is larger, the process proceeds to Step 26 (No) if it has been determined in Step 22 (No), and it is determined that the roll urgency is small.
[0052]
  In addition, the process in step 22-step 26 corresponds to an emergency degree determination means.
  In step 27 where the roll urgency is determined to be large, the current average roll angle θ_aveIs the predetermined value θ_ThreeIt is determined whether or not it is larger. And the current average roll angle θ_aveThe absolute value of_ThreeIf it is larger, the process proceeds to Step 17 (Yes), and the current average roll angle θ_aveThe absolute value of_ThreeIf it is below, the process is terminated (No).
[0053]
In step 28 where the roll urgency is determined to be medium, the current average roll angle θ_aveIs the predetermined value θ₂It is determined whether or not it is larger. And the current average roll angle θ_aveThe absolute value of₂If it is larger, the process proceeds to Step 17 (Yes), and the current average roll angle θ_aveThe absolute value of₂If it is below, the process is terminated (No).
[0054]
In step 29 where the roll urgency is determined to be small, the current average roll angle θ_aveIs the predetermined value θ₁It is determined whether or not it is larger. And the current roll angle θ_aveThe absolute value of₁If it is larger, the process proceeds to Step 17 (Yes), and the current roll angle θ_aveThe absolute value of₁If it is below, the process is terminated (No).
[0055]
  In addition, the process in step 27-step 29 corresponds to a danger determination means.
  According to the processing of step 21 to step 29 described above, the current average roll angle θ_aveIn addition, an estimated roll angle θ ′ after a predetermined time t has been calculated based on the roll angular velocity ω or the roll angular acceleration α. Based on the calculated estimated roll angle θ ′, whether the roll urgency level is large, medium or small is determined. For this reason, compared with the previous embodiment, the determination accuracy of the roll urgency is improved, and a warning can be issued to the driver at a more appropriate time. Further, similarly to the previous embodiment, a correction value Δθ corresponding to the roll angular velocity ω is set, and the current average roll angle θ is set in steps 27 to 29._aveIs the predetermined value θ_1,2,3It may be determined whether or not the sum of the correction value and the correction value Δθ is larger.
[0056]
  Further, when determining the risk of vehicle rollover in step 27 to step 29, the current average roll angle θ_aveInstead, the estimated roll angle θ ′ calculated in step 21 may be used. In this case, since the risk of vehicle rollover is determined based on the estimated roll angle θ ′ after a predetermined time has elapsed, the determination accuracy can be further improved. Here, the process of determining the risk of vehicle rollover based on the estimated roll angle θ ′,Risk assessment meansIt corresponds to.
[0057]
The vehicle height sensor may detect vehicle left and right vehicle heights on the front axle. In this case, since the roll of the vehicle is started from the front shaft to which the steered wheels are connected, the roll state is predicted earlier. And the safety | security can be improved more because the warning with respect to a driver | operator is performed with margin.
When it is determined that the risk of vehicle rollover is great, as shown in FIG. 7, the auxiliary wheels 30L and 30R (roll angle limiting means) mounted on the left and right sides of the vehicle are operated, and the roll angle θ is You may make it become below a limit value.
[0058]
【The invention's effect】
  As described above, according to the first aspect of the present invention, since the warning to the driver is issued early based on the prediction of the roll state of the vehicle, there is enough time to start the danger avoidance operation. Therefore, safety in vehicle operation can be improved.Further, for example, even if fine vibration due to road surface unevenness is detected, since it is smoothed by calculating the moving average, it is possible to prevent an inappropriate warning from being issued.
[0059]
  According to invention of Claim 2,, Roll angleAs time increases, the predetermined time can be reduced.
[0060]
  According to invention of Claim 3, a roll angle or its moving averageWhen the absolute value of is greater than the sum of the predetermined value and the correction value, it can be determined that there is a risk of vehicle rollover.
[0061]
  Claim 4According to the described invention, since the roll angle is reduced by the deceleration of the vehicle, the risk of vehicle rollover can be reduced even if the danger avoidance operation by the driver is delayed.
  Claim 5According to the described invention, for example, the vehicle can be decelerated only by transmitting a control command to the brake controller or / and the engine controller, and the control contents can be prevented from becoming complicated.
[Brief description of the drawings]
FIG. 1 is a configuration diagram in which a rollover prevention device according to the present invention is applied to a tractor.
FIG. 2 is an explanatory diagram of functions realized by the control unit.
FIG. 3 is a flowchart showing an example of control content.
FIG. 4 is a flowchart showing an example of control content.
FIG. 5 is an explanatory diagram showing a roll angle calculation method.
FIG. 6 is a flowchart showing another example of control content.
FIG. 7 is an explanatory diagram of an auxiliary wheel for setting a roll angle to a limit value or less.
[Explanation of symbols]
    16L, 16R Vehicle height sensor
    18 Roll indicator
    22 Alarm
    24 Control unit
    24a Roll angle calculation unit
    24b Roll angular velocity calculation unit
    24c Roll Urgency Determination Unit
    24d Rollover risk determination unit
    24e Indicator control unit
    24f Alarm control unit
    24g Deceleration control unit
    26 Engine controller
    28Brake controller

Claims (5)

Vehicle height detection means for detecting vehicle height on the left and right sides of the vehicle;
Roll angle calculating means for calculating the roll angle of the vehicle based on the detected vehicle height;
A moving average calculating means for calculating a moving average of the calculated roll angle;
Roll angular velocity calculating means for calculating the roll angular velocity of the vehicle based on the calculated rate of change of the moving average of the roll angle;
A roll angle estimating means for estimating a roll angle of the vehicle after a predetermined period of time based on the calculated moving average of the roll angles and the roll angular velocity ;
By comparing the absolute value of the estimated roll angle with a first threshold value defining a region where the roll urgency level is large and a second threshold value defining a region where the roll urgency level is small, Urgency determination means for determining whether the degree of urgency is “large”, “medium”, or “small” as a scale indicating risk,
When the calculated absolute value of the moving average of the roll angle or the absolute value of the estimated roll angle is larger than a predetermined value corresponding to the urgency determined by the urgency determining means, it is determined that there is a risk of vehicle rollover Risk judging means to
Warning generation means for issuing a warning to the driver when the risk determination means determines that there is a risk of vehicle rollover;
An apparatus for preventing rollover of a vehicle, comprising: 2. The vehicle rollover prevention device according to claim 1 , wherein the predetermined time is set so as to decrease as the roll angular velocity increases . Correction value setting means for setting a correction value for correcting the predetermined value based on the absolute value of the roll angular velocity,
When the absolute value of the calculated moving average of the roll angles or the estimated absolute value of the roll angle is greater than the sum of the predetermined value and the correction value, the risk determination means has a risk of vehicle rollover. The vehicle rollover prevention device according to claim 1 or 2, wherein the determination is made . The vehicle according to any one of claims 1 to 3, further comprising a vehicle deceleration unit that decelerates the vehicle when the risk determination unit determines that there is a risk of vehicle rollover. Rollover prevention device. The vehicle deceleration means is
Brake actuating means for actuating the brake of the vehicle;
Fuel reduction means for reducing fuel supplied to the internal combustion engine;
The vehicle rollover prevention device according to claim 4, wherein the device is at least one of the above.

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