JP4325300B2 - Vehicle behavior control device - Google Patents

Description

【００１９】
ここで、上記ステップＳ２００、Ｓ２１０が作動閾値設定変更手段１０２を構成する。
続いて、ステップＳ２４０では、車体速度Ｖ、限界車体速度ＶL 、旋回半径Ｒ、限界旋回半径ＲL に基づき、目標減速度ＤＤＸＧを演算し、ステップＳ２５０に移行する。ステップＳ２５０では、上記目標減速度ＤＤＸＧを得るための前後輪の各目標ブレーキ液圧を求め、ステップＳ２６０に移行する。
【００２０】
ステップＳ２６０では、圧力切り換え弁７をＯＮ（図２右側の状態）にする。これによりアキュムレータ内の液圧がプランジャに作用して、該プランジャ内の圧液が圧力調整器１１，２１，３１，４１側に送られる。ステップＳ２７０では、各輪毎に配分され目標ブレーキ液圧を得るのに必要な圧力調整器１１，２１，３１，４１の各ソレノイドへの供給電流ｉＦＬ、ｉＦＲ、ｉＲＬ、ｉＲＲを求め、ステップＳ２８０にて各ソレノイドに電流を供給してブレーキ圧力制御を行うことにより車両ＷＶの減速度を得る。すなわち、圧力調整器１１，２１，３１，４１について、それぞれ弁位置を図２の左側の位置にすると、プランジャ５，６からブレーキのキャリパ１２，２２，３２，４２へ圧液が送られて、ブレーキ液圧が増圧される。また、弁位置が中立位置にあるときには、液路が遮断されることによりブレーキ液圧は一定に保持される。一方、弁位置が右側の位置にあるときにはブレーキ液はリザーバタンク２０，４０側へ戻される。このように圧力調整器１１，２１，３１，４１の切換位置を制御することにより各輪のブレーキ圧が制御される。なお、リザーバタンク２０，４０の圧液はポンプ１９，２９によりリザーバタンク３に戻される。
【００２１】
一方、ステップＳ２９０では、目標減速度ＤＤＸＧを得るためのエンジン出力制御信号を演算する。例えば、スロットル開度によりエンジン出力を制御する場合には、ブレーキによって得られる減速度との関係を考えて目標スロットル開度を決定し、目標スロットル開度を得るための制御信号を演算する。続いて、ステップＳ３００で、エンジン出力調整器を駆動する。前記した例ではスロットルを駆動することになる。
【００２２】
次に、ＴＣＳ制御部１００の処理を、図７のフロー図に基づき説明すると、所定のサンプリング時間毎に作動して、まずステップＳ４００にて、各車輪速を入力してステップＳ４１０に移行する。
ステップＳ４１０では、加速スリップ量ΔＶrealを演算してステップＳ４２０に移行する。例えば、下記式のように、駆動輪側（下記式は後輪側が駆動輪の場合の式である）の平均車輪速から非駆動輪側の平均車輪速を引いた車輪速をスリップ量ΔＶrealとする。
ΔＶreal＝ＶＲａｖｅｒａｇｅ −ＶＦａｖｅｒａｇｅ
【００２３】
ステップＳ４２０では、補正値αを入力し、ステップＳ４２０で、下記式のように、上記ＴＣＳスリップ量に対する作動閾値の基本値△Ｖｔのから補正値αを引いて、補正分だけＴＣＳスリップ量閾値△Ｖｔを下げて、ステップＳ４４０に移行する。このステップＳ４２０及びＳ４３０は、作動閾値設定手段を構成する。
ΔＶｔｃｓ ＝ΔＶｔ −α
【００２４】
ステップＳ４４０では、実測されたスリップ量ΔＶrealと上記補正後のＴＣＳスリップ量閾値△Ｖｔｃｓとを比較して、実測スリップ量ΔＶrealがＴＣＳスリップ量閾値△Ｖｔｃｓを越えている場合にはステップＳ４５０に移行し、越えていない場合には、作動介入することなく復帰する。
ステップＳ４５０では、公知の手段によってＴＣＳ制御の作動処理を実施し、つまり、上記スリップ量を低減するためのエンジントルク低減量や制動力を演算し、その演算した値となるようにエンジントルクを低減させたり、各車輪に制動力を付与したりする。
【００２５】
次に、上記構成の制御装置の動作や作用・効果について説明する。
車両が直進路を走行中や、曲線路であっても旋回状態が十分に安定して旋回走行可能な状態のような車両挙動状態にあっては、駆動輪の加速スリップを抑えるＴＣＳ制御の作動介入は、従来通りのＴＣＳスリップ量閾値△Ｖｔ（基本値）が採用されて、ＴＣＳ制御の不要な早期作動介入が防止される。なお、ＴＣＳスリップ量閾値の基本値である△Ｖｔを小さくして常にＴＣＳ制御の作動を早期介入をさせるようにした場合には、直進路を走行中であっても、頻繁にＴＣＳ制御の作動・非作動が繰り返し発生するおそれがある。
【００２６】
一方、曲線路を走行中であって車両の旋回状態が限界旋回状態に近い状態、つまり旋回安定確保のためのＣＯＰ制御による自動制動制御が作動中に、運転者が加速操作などを行った場合や、運転者が加速操作をした状態で車両の旋回状態が限界旋回状態に近い状態になった場合には、上述の通常状態に比べてＴＣＳ制御の早期作動介入が可能となる。この結果、通常のＴＣＳでは防止できない駆動輪の加速スリップを早期に抑制できることで、駆動輪の横力を確保し車両の安定性を高めることができる。
【００２７】
このとき、本実施形態では、車両の旋回状態量に応じてＴＣＳスリップ量閾値△Ｖｔ（基本値）を補正、つまり、旋回状態量が大きいほどＴＣＳスリップ量閾値△Ｖｔｃｓを小さくして、よりＴＣＳの早期作動介入を行うように設定することで、車両旋回状態に応じたＴＣＳスリップ量閾値△Ｖｔｃｓが設定される。この結果、運転者はその車両状態に適したアクセルコントロールを行うようになるために、運転者の意思を反映することが可能となり、加速不良（失速感）のような違和感を無くすことが可能となる。
【００２８】
さらに、旋回半径が強まる（小さくなる）場合と弱まる（大きくなる）場合とで補正値αの値を設定変更し、コーナインなどの車両旋回状態が強まる方向では、車両旋回状態が弱まる方向に移行する場合に比べて、相対的に補正値αが大きくなるように設定変更している。この結果、例えばＣＯＰ制御の作動中にステアリングホイールを切り込むような状況では、相対的に上記ＴＣＳスリップ量閾値△Ｖｔｃｓがより小さな値に変更されて、切り込む前に比べて相対的に車両が不安定状態になった時に運転者が加速操作を行っても、ＴＣＳ制御がより早期から作動して横力を確保することで車両安定性を高めることが可能となる。また、ＣＯＰ制御作動中にステアリングを切戻す状況では、切込み時に比べ、相対的にＴＣＳの作動閾値が上がることで、運転者が加速操作を行った場合でもＴＣＳ制御が早期作動介入しないため、加速不良（失速感）のような違和感を無くすことを可能となる。
【００２９】
以上により、ＣＯＰ制御の作動中に運転者が加速操作を行っても、ＴＣＳ制御の通常の作動閾値ΔＶｔを車両旋回状態量、更には車両旋回状態の増減方向に応じて、下げ量を変更することで、ＴＣＳ制御の作動が早期から作動して、駆動輪の横力を確保して車両安定性を高めると共に、運転者がそれらの状態に適したアクセルコントロールを行うために、運転者の意思を反映することが可能となり、加速不良（失速感）のような違和感を無くすことを可能とする。
【００３０】
図８に、車両の前後力及び横力とスリップ率との関係を示す。車両の旋回状態量が大きい挙動状態を発生しているときに、ＴＣＳ制御の早期作動介入を行うことで、大きな横力を確保できることが分かる。
また、図９に本実施形態についてのタイムチャート例を示す。図９に示されるように、ＣＯＰ制御の作動中に加速スリップが発生した場合に、ＴＣＳ制御の早期作動介入によって、駆動輪のスリップを早期に収束させることができる。図９の破線は、ＴＣＳ制御の作動閾値をΔＶｔと固定した場合の例である。
【００３１】
ここで、上記実施形態では、ＴＣＳスリップ量閾値△Ｖｔを補正する補正値αを車両の旋回状態量に応じて変更した場合を例示しているが、路面μなどの路面状態量に応じて補正値αを決定しても良い。この場合には、路面状態量が大きいほど補正値αが小さくなるように設定する。
また、上記実施形態では、作動閾値ΔＶｔに対して、補正値αを加減算することで作動閾値を補正しているが、これに限定しない。補正値を乗除算することで作動閾値を補正するようにしても良い。
【００３２】
ここで、上記路面状態量とは、路面μや路面の悪路状態などを指す。
また、上記実施形態では、ＴＣＳ制御のＴＣＳスリップ量閾値自体を補正することで、ＴＣＳの早期作動介入を実現しているが、これに限定されない。例えば、実測スリップ量に補正値を加算するなどして、結果的に加速スリップ量に対する作動閾値を下げることで、早期作動介入を実現するようにしても良い。
【００３３】
ここで、上記実施形態では、ＴＣＳとＣＯＰの制御システムの両方が搭載している場合で挙げているが、これに限定されない。例えばＣＯＰの制御システムを搭載せず、ＴＣＳの制御システムだけを搭載した車両について、ＴＣＳの作動閾値を旋回状態量や路面状態量に応じて変更するようにしても良い。
次に、第２実施形態を図面を参照しつつ説明する。なお、上記第１実施形態と同様な処理などについては同一の符号を付して説明する。
【００３４】
本第２実施形態の基本構成は、上記第１実施形態と同様であるが、ＣＯＰ制御による自動制動の作動を、運転者による加速操作があると判定すると停止する点が異なる。
すなわち、図１０に示すように、ＣＯＰ制御部１０１の処理の一部が異なる。なお、上記第１実施形態と同じ処理ブロックは同一の符号を付して説明する。
第２実施形態のＣＯＰ制御部１０１では、ステップＳ１８０にてＣＯＰの作動を行うと判断しステップＳ１９０にてＣＯＰ作動フラグＣＯＰに「１」を代入した後にステップＳ５００に移行する。
【００３５】
ステップＳ５００では、アクセルフラグなどから運転者の加速意思の有無を判断し、運転者が加速意思として加速操作をしたと判定するとステップＳ５１０に移行する。一方、加速操作がされていないと判断したときにはステップＳ２４０〜ステップＳ３００の処理を行って、安定旋回を確保するための自動的な制動操作を行う。上記ステップＳ５００は、加速意思検出手段を構成する加速意思検出部である。
加速操作が行われていると判断されてステップＳ５１０に移行すると、ＣＯＰ作動の終了処理を実施した後に、第１実施形態と同様に、ステップＳ２００，Ｓ２１０によって補正値αを演算した後、復帰する。
その他の処理は、上記第１実施形態と同様である。
【００３６】
次に、本実施形態では、運転者により加速の意思があると判断すると、ＣＯＰ制御による自動的な制動処理を停止するが、このときＴＣＳ制御の作動閾値を下げることで、ＴＣＳ制御の作動介入が早期されることとなる。この結果、加速操作と共にＣＯＰ制御による自動制動の停止があることで、早期に駆動輪が加速スリップしても早期に加速スリップを抑制することができ、つまり駆動輪の横力を確保して車両安定性を高めることができる。なお、加速スリップが抑制されてＴＣＳ制御の作動が中止されると、上記ＴＣＳ制御の作動閾値は初期値に戻る。
【００３７】
これによって、運転者が車両の挙動状態に適したアクセルコントロールを行うために、運転者の意思を反映することが可能となり、加速不良（失速感）のような違和感を無くすことが可能となる。
図１１に、本第２実施形態におけるタイムチャート例を示す。運転者が加速意思があると判定してＣＯＰ制御の作動を中止しても、ＴＣＳ制御の早期介入が行われてスリップが早期に収束する。破線は、ＴＣＳ制御の作動閾値をΔＶｔと一定に固定した場合に例である。
その他の作用・効果は上記第１実施形態と同様である。
【図面の簡単な説明】
【図１】本発明に基づく実施形態に係るシステム構成を示す図である。
【図２】本発明に基づく第１実施形態に係る液圧系を示すシステム図である。
【図３】本発明に基づく実施形態に係るコントローラの構成を示す図である。
【図４】本発明に基づく第１実施形態に係るＣＯＰ制御部の処理フローを示す図である。
【図５】左右加速度（旋回状態量）と補正値αとの関係を示す図である。
【図６】旋回方向の変化状態による補正値αの補正イメージを示す概念図である。
【図７】本発明に基づく第１実施形態に係るＴＣＳ制御部の処理フローを示す図である。
【図８】前後力及び横力と駆動輪のスリップ率との関係を示す図である。
【図９】本発明に基づく第１実施形態に係るタイムチャート例を示す図である。
【図１０】本発明に基づく第２実施形態に係るＣＯＰ制御部の処理フローを示す図である。
【図１１】本発明に基づく第２実施形態に係るタイムチャート例を示す図である。
【符号の説明】
１４ コントローラ
１００ ＴＣＳ制御部
１００Ａ 加速スリップ検出部
１００Ｂ 加速スリップ作動閾値演算部
１００Ｃ ＴＣＳ作動介入判定部
１００Ｄ トラクション低減部
１０１ ＣＯＰ制御部
１０１Ａ 旋回状態検出部
１０１Ｂ 旋回限界演算部
１０１Ｃ ＣＯＰ作動介入判定部
１０１Ｄ 制動部
１０２ 作動閾値設定変更手段
１０３ 加速意思検出部
ΔＶｔ ＴＣＳ制御の作動閾値（基本値）
ΔＶｔｃｓ ＴＣＳ制御の作動閾値（補正後の値）
α 補正値[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle behavior control device that controls the behavior of a vehicle in accordance with the behavior state of the vehicle.
[0002]
[Prior art]
As a vehicle behavior control device, for example, a traction controller system (hereinafter also referred to as TCS) is known. In this TCS, when an acceleration slip exceeding a predetermined operation threshold occurs in the driving wheel, the acceleration slip is suppressed by suppressing the driving force, and the vehicle behavior is stabilized. However, when the vehicle is traveling on a curved road and the acceleration slip amount is less than the predetermined operation threshold, the TCS control does not operate until a so-called spin behavior is induced.
[0003]
In view of these points, the applicants have invented an automatic braking control system (hereinafter also referred to as COP) described in Patent Document 1 in order to improve turning stability. The control system detects a turning state quantity of the vehicle, and determines that the turning state quantity has approached a set limit operation value with respect to a turning limit state quantity at which the vehicle can travel stably. A target deceleration required to enable traveling is calculated, and a braking force corresponding to the target deceleration is applied to the vehicle.
[0004]
Furthermore, in Patent Document 2, even when the automatic braking control system is activated and automatic braking is applied, if the driver performs an acceleration operation, the automatic braking processing by the automatic braking control is performed. It is disclosed that the acceleration traveling according to the driver's intention is realized by terminating the operation, that is, canceling the automatic deceleration braking at all.
[0005]
[Patent Document 1]
Japanese Patent Publication No. 2600876 [Patent Document 2]
JP-A-2002-127888 [0006]
[Problems to be solved by the invention]
Here, since the driving skill of the driver is various, when the automatic braking control is activated and the vehicle is automatically decelerated, there may be a gap with the feeling of deceleration intended by the driver. At this time, when the feeling of deceleration due to the operation of the automatic braking control is greater, assuming that the driver depresses the accelerator pedal in order to fill this gap, particularly in the corner, it is described in Patent Document 2. In the control system, since the automatic deceleration braking is released by the driver's acceleration operation, the driving force suddenly increases, so that, for example, when traveling on a low μ road, an acceleration slip may occur on the driving wheel. .
The present invention has been made in view of the above points, and provides a vehicle behavior control device that can appropriately suppress slippage of drive wheels even during traveling on a curved road. It is an issue.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention detects acceleration slip of a drive wheel, and when it is determined that the acceleration slip amount is equal to or greater than a predetermined operation threshold, control of braking force application or drive force suppression for acceleration slip reduction. in behavior control device for the vehicle with the acceleration slip suppression control means for performing state, and are not to correct the actuation threshold for the acceleration slip amount in accordance with the turning state of the vehicle indicated by like turning state quantity of the vehicle, turning As the state becomes stronger, the operation threshold for the acceleration slip amount is corrected to a smaller value. Furthermore, the operation threshold value for the acceleration slip amount is corrected in accordance with the change state of the turning state of the vehicle, and the operation threshold value is corrected to a small value when the turning state changes in the increasing direction.
Here, the “operation threshold for the acceleration slip amount” includes not only correcting the operation threshold itself, but also correcting the operation threshold substantially by correcting the acceleration slip amount side.
[0008]
【The invention's effect】
According to the present invention, the operation intervention time of the acceleration slip suppression control means can be changed to a time according to the behavior state of the vehicle.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the overall configuration of the present embodiment.
First, the configuration will be described. The wheel speeds of the front and rear wheels are detected by the respective wheel speed sensors 51, and the detection signals are output to the controller 14. In addition, an acceleration sensor 52 that detects the longitudinal and lateral acceleration of the vehicle, a steering angle sensor 53 that detects the steering angle of the steering wheel, a switch group 54 such as a brake switch, a pressure switch, and an accelerator switch, a yaw around the center of gravity of the vehicle A yaw angular acceleration sensor 55 that detects angular acceleration and a hydraulic pressure sensor group 56 that detects the hydraulic pressure of each wheel cylinder are arranged, and each of these sensors and switches 51 to 56 outputs detection signals to the controller 14. The yaw angular acceleration sensor 55 and the hydraulic pressure sensor group 56 are used as necessary to improve control accuracy.
[0010]
The controller 14 performs arithmetic processing based on the various signals from the sensors and switches described above, and controls the brake actuator 16 that adjusts the brake pressure of each front and rear wheel, and the engine output adjuster 17 that adjusts the engine output. A control signal is output and controlled.
The brake actuator 16 includes a pressure switching valve 7 and pressure regulators 11, 21, 31, 41 arranged in the brake system of each wheel.
[0011]
A configuration example of the braking means will be described with reference to FIG. 2. Reference numeral 1 is a brake pedal, reference numeral 2 is a booster, reference numeral 3 is a reservoir, and reference numeral 4 is a master cylinder. Reference numerals 5 and 6 are plungers, reference numeral 7 is a switching valve, reference numeral 8 is an accumulator, reference numeral 9 is a pump, and reference numeral 15 is a reservoir. The reservoirs 3 and 15 may be the same. Reference numerals 10 and 30 are accumulators similar to the anti-skid accumulator, and reference numerals 20 and 40 are reservoir tanks similar to the anti-skid reservoir tank. Reference numerals 19 and 29 are pumps. Reference numerals 11, 21, 31, and 41 are solenoid valves, reference numerals 12, 22, 32, and 42 are calipers, and reference numerals 13, 23, 33, and 43 are disk rotors, each having four wheels. Reference numerals a1 to a4 are output signals from the wheel speed sensor 51 of each wheel, and are used for anti-skid and traction control. Symbol a5 is an output signal from the steering angle sensor 53, and symbols a6 and a7 are signals from the front and rear acceleration sensors 52a and 52b, respectively. In FIG. 2, the yaw angular acceleration sensor 55, the hydraulic pressure sensor 56 of each wheel, and various switch groups 54 are omitted. b is a control signal to the engine output regulator 17.
[0012]
Next, as shown in FIG. 3, the controller 14 includes a TCS control unit 100, a COP control unit 101, and an operation threshold setting change unit 102. In FIG. 3, the processing block (acceleration intention detection unit 103) used in the second embodiment is also shown.
The COP control unit 101 constitutes an automatic braking control unit, and includes a turning state detection unit 101A, a turning limit calculation unit 101B, a COP operation intervention determination unit 101C, and a braking unit 101D. In addition, the TCS control unit 100 constitutes an acceleration slip suppression control unit, and includes an acceleration slip detection unit 100A, an acceleration slip operation threshold value calculation unit 100B, a TCS operation intervention determination unit 100C, and a traction reduction unit 100D.
[0013]
The processing of the COP control unit 101 will be described based on the processing flow shown in FIG. 4. This control processing is performed every predetermined sampling time. First, in step S100, the wheel speeds VFL, VFR, VRL, VRR is input, a steering angle θ is input in step S110, and accelerations DDX and DDY in the front-rear direction and the left-right direction of the vehicle are input in step S120. In step S130, the vehicle body speed V is calculated from the wheel speeds VFL, VFR, VRL, VRR and the vehicle body longitudinal acceleration, and the process proceeds to step S140.
[0014]
In step S140, the slip ratios SFL, SFR, SRL, SRR of each wheel are obtained from each wheel speed and the vehicle body speed V. In step S150, the turning radius R is calculated based on the following equation from the vehicle body speed V and the vehicle body lateral acceleration DDY, and the process proceeds to step S160.
R = (V ² / DDY)
The above processing steps constitute the turning state detection unit 101A.
In step S160, the limit turning radius RL at the current vehicle speed V is obtained from the vehicle speed V. For example, if the limit vehicle body lateral acceleration determined by the vehicle is DDY1, it can be obtained by RL = (V ² / DDY1).
Subsequently, in step S170, the limit turning speed VL at the current turning radius R is obtained from the turning radius R based on the following equation, and the process proceeds to step S180.
VL = √ (R · DDY1)
[0015]
Here, the limit vehicle body lateral acceleration DDY1 may be changed according to the slip ratios SFL, SFR, SRL, and SRR of each wheel. Steps S160 and S170 constitute a turning limit calculation unit 101B.
In step S180, it is determined what value the turning radius R is with respect to the limit turning radius RL or the vehicle body speed V is with respect to the limit turning vehicle speed VL, and allowable values kVL and hRL (however, k are the threshold values). , H <1), that is, when the vehicle body speed V is larger than the allowable value kVL or the turning radius R is smaller than the allowable value hRL, the brake control process is performed. The process proceeds to step S190. If the allowable value is not exceeded, the process proceeds to step S220. Here, the coefficients k and h (k and h are coefficients slightly smaller than 1) of the allowable values kVL and hRL are determined in advance. Step S180 constitutes the COP operation intervention determination unit 101C.
[0016]
In step S220, “0” indicating non-operation is substituted for the flag COP, and in step S230, the initial value “0” is substituted for the correction value α, and then the process returns.
On the other hand, in step S190, “1” indicating the operation is substituted for the flag COP, and the process proceeds to step S200.
In step S200, the correction value α corresponding to the turning state amount of the vehicle is calculated based on the lateral acceleration that is one of the turning state amounts, and the process proceeds to step S210. The correction value α is set so as to increase as the lateral acceleration increases, that is, as the turning state amount increases, as shown in the graph of FIG. 5, and the process proceeds to step S210. The larger the correction value α is, the smaller the operation threshold value for TCS control is corrected.
[0017]
Here, the turning state quantity is not limited to the lateral acceleration. Any state quantity that represents the degree of the turning state of the vehicle, such as the reciprocal of the turning radius R and the steering angle amount, may be used. The turning state amount is set so as to increase as the turning state becomes stronger.
In step S210, the correction value α is corrected based on the turning radius change state, and the process proceeds to step S240. That is, if it is determined that the turning radius is changed in the direction of decreasing (increasing), the correction value α is changed in the direction of increasing, and the turning radius is changed in the direction of increasing (decreasing). When the determination is made, the correction value α is changed in a decreasing direction. FIG. 6 shows an image diagram thereof. For example, when the correction value corresponding to the change state of the turning radius is set to β (> 0), when it is determined that the turning radius R changes in a direction of decreasing (increasing), “α ← α + β” If it is determined that the turning radius is changing (decreasing), the setting is changed by correcting “α ← α−β”.
[0018]
Here, the changing direction of the turning radius can be determined by comparing the previous value and the current value of the turning radius.
Further, when the correction amount of the correction value α is corrected by an amount corresponding to the change rate of the turning radius R, for example, the correction value β is obtained by multiplying the change rate of the following equation by a predetermined coefficient. Let Δt be the time for one control cycle.

[0019]
Here, the steps S200 and S210 constitute the operation threshold setting changing means 102.
Subsequently, in step S240, the target deceleration DDXG is calculated based on the vehicle body speed V, the limit vehicle body speed VL, the turning radius R, and the limit turning radius RL, and the process proceeds to step S250. In step S250, the target brake hydraulic pressures of the front and rear wheels for obtaining the target deceleration DDXG are obtained, and the process proceeds to step S260.
[0020]
In step S260, the pressure switching valve 7 is turned on (state on the right side in FIG. 2). As a result, the hydraulic pressure in the accumulator acts on the plunger, and the pressurized fluid in the plunger is sent to the pressure regulators 11, 21, 31, 41 side. In step S270, the supply currents iFL, iFR, iRL, iRR to the solenoids of the pressure regulators 11, 21, 31, 41 required to obtain the target brake fluid pressure distributed to each wheel are obtained, and the process proceeds to step S280. Then, a deceleration of the vehicle WV is obtained by supplying a current to each solenoid and performing a brake pressure control. That is, with respect to the pressure regulators 11, 21, 31, and 41, when the valve position is set to the left position in FIG. 2, the pressure fluid is sent from the plungers 5 and 6 to the calipers 12, 22, 32, and 42 of the brake, The brake fluid pressure is increased. When the valve position is in the neutral position, the brake fluid pressure is kept constant by blocking the fluid passage. On the other hand, when the valve position is on the right side, the brake fluid is returned to the reservoir tanks 20 and 40 side. Thus, the brake pressure of each wheel is controlled by controlling the switching position of the pressure regulators 11, 21, 31, 41. The pressurized liquid in the reservoir tanks 20 and 40 is returned to the reservoir tank 3 by the pumps 19 and 29.
[0021]
On the other hand, in step S290, an engine output control signal for obtaining the target deceleration DDXG is calculated. For example, when the engine output is controlled by the throttle opening, the target throttle opening is determined in consideration of the relationship with the deceleration obtained by the brake, and a control signal for obtaining the target throttle opening is calculated. Subsequently, in step S300, the engine output adjuster is driven. In the above example, the throttle is driven.
[0022]
Next, the processing of the TCS control unit 100 will be described based on the flowchart of FIG. 7. The TCS control unit 100 operates every predetermined sampling time. First, in step S400, each wheel speed is input and the process proceeds to step S410.
In step S410, the acceleration slip amount ΔVreal is calculated, and the process proceeds to step S420. For example, as shown in the following expression, the wheel speed obtained by subtracting the average wheel speed on the non-driving wheel side from the average wheel speed on the driving wheel side (the following expression is an expression when the rear wheel side is the driving wheel) is the slip amount ΔVreal. To do.
ΔVreal = VRaverage−VFaverage
[0023]
In step S420, the correction value α is input, and in step S420, the correction value α is subtracted from the basic value ΔVt of the operation threshold for the TCS slip amount as shown in the following equation, and the TCS slip amount threshold Δ Vt is lowered and the process proceeds to step S440. Steps S420 and S430 constitute operation threshold setting means.
ΔVtcs = ΔVt−α
[0024]
In step S440, the actually measured slip amount ΔVreal is compared with the corrected TCS slip amount threshold value ΔVtcs. If the actually measured slip amount ΔVreal exceeds the TCS slip amount threshold value ΔVtcs, the process proceeds to step S450. If not exceeded, return without intervention.
In step S450, a TCS control operation process is performed by a known means, that is, the engine torque reduction amount and the braking force for reducing the slip amount are calculated, and the engine torque is reduced to the calculated value. Or apply braking force to each wheel.
[0025]
Next, the operation, action, and effect of the control device having the above configuration will be described.
TCS control operation that suppresses acceleration slip of the drive wheel when the vehicle is running on a straight road or in a vehicle behavior state where the turning state is sufficiently stable even if it is a curved road For the intervention, a conventional TCS slip amount threshold value ΔVt (basic value) is adopted, and an unnecessary early intervention of TCS control is prevented. In addition, when ΔVt, which is the basic value of the TCS slip amount threshold value, is reduced so that the TCS control operation is always performed at an early stage, the TCS control operation is frequently performed even on a straight road.・ Non-operation may occur repeatedly.
[0026]
On the other hand, when the driver performs an acceleration operation or the like while driving on a curved road and the turning state of the vehicle is close to the limit turning state, that is, when automatic braking control by COP control for ensuring turning stability is operating In addition, when the driver performs an acceleration operation and the turning state of the vehicle is close to the limit turning state, early operation intervention of TCS control is possible as compared with the above-described normal state. As a result, the acceleration slip of the drive wheel that cannot be prevented by normal TCS can be suppressed at an early stage, so that the lateral force of the drive wheel can be secured and the stability of the vehicle can be improved.
[0027]
At this time, in the present embodiment, the TCS slip amount threshold value ΔVt (basic value) is corrected according to the turning state amount of the vehicle, that is, the larger the turning state amount, the smaller the TCS slip amount threshold value ΔVtcs. By setting so as to perform the early operation intervention, the TCS slip amount threshold value ΔVtcs corresponding to the vehicle turning state is set. As a result, since the driver performs accelerator control suitable for the vehicle state, it is possible to reflect the driver's intention, and it is possible to eliminate a sense of incongruity such as poor acceleration (a feeling of stall). Become.
[0028]
Furthermore, the value of the correction value α is changed depending on whether the turning radius is strengthened (decrease) or weakened (increased), and in a direction where the vehicle turning state such as a corner is strengthened, the vehicle turning state is weakened. Compared to the case, the setting is changed so that the correction value α is relatively large. As a result, for example, in a situation where the steering wheel is cut during the operation of the COP control, the TCS slip amount threshold value ΔVtcs is changed to a relatively smaller value, and the vehicle is relatively unstable compared to before turning. Even if the driver performs an accelerating operation when the vehicle enters a state, the vehicle stability can be enhanced by ensuring that the TCS control is activated from an earlier stage and the lateral force is secured. Also, in the situation where the steering wheel is turned back during the COP control operation, the TCS operation threshold value is relatively higher than that at the time of the cutting operation, so that even if the driver performs an acceleration operation, the TCS control does not intervene early. It is possible to eliminate a sense of incongruity such as a defect (a feeling of stall).
[0029]
As described above, even when the driver performs an acceleration operation during the operation of the COP control, the normal operation threshold value ΔVt of the TCS control is changed according to the vehicle turning state amount and further the increase / decrease direction of the vehicle turning state. Therefore, the TCS control is activated from an early stage to ensure the lateral force of the drive wheels to improve vehicle stability, and for the driver to perform accelerator control suitable for those conditions, Can be reflected, and it is possible to eliminate a sense of incongruity such as poor acceleration (a feeling of stall).
[0030]
FIG. 8 shows the relationship between the longitudinal force and lateral force of the vehicle and the slip ratio. It can be seen that a large lateral force can be secured by performing early operation intervention of the TCS control when a behavior state with a large amount of turning state of the vehicle is generated.
FIG. 9 shows an example of a time chart for this embodiment. As shown in FIG. 9, when an acceleration slip occurs during the operation of the COP control, the slip of the drive wheels can be converged early by the early operation intervention of the TCS control. The broken line in FIG. 9 is an example when the operation threshold value of TCS control is fixed to ΔVt.
[0031]
Here, in the above embodiment, the case where the correction value α for correcting the TCS slip amount threshold value ΔVt is changed according to the turning state amount of the vehicle is exemplified, but the correction value α is corrected according to the road surface state amount such as the road surface μ. The value α may be determined. In this case, the correction value α is set to be smaller as the road surface state amount is larger.
Moreover, in the said embodiment, although an operation threshold value is correct | amended by adding / subtracting the correction value (alpha) with respect to the operation threshold value (DELTA) Vt, it is not limited to this. The operating threshold value may be corrected by multiplying and dividing the correction value.
[0032]
Here, the road surface state quantity refers to a road surface μ, a bad road state of the road surface, and the like.
Moreover, in the said embodiment, although the TCS slip amount threshold value of TCS control itself is correct | amended, the early operation intervention of TCS is implement | achieved, However, it is not limited to this. For example, the early operation intervention may be realized by adding a correction value to the actually measured slip amount and consequently lowering the operation threshold for the acceleration slip amount.
[0033]
Here, in the said embodiment, although mentioned in the case where both the control system of TCS and COP are mounted, it is not limited to this. For example, the TCS operation threshold may be changed according to the turning state amount or the road surface state amount for a vehicle that is not equipped with a COP control system but is equipped with only a TCS control system.
Next, a second embodiment will be described with reference to the drawings. The same processes as those in the first embodiment will be described with the same reference numerals.
[0034]
The basic configuration of the second embodiment is the same as that of the first embodiment, except that the operation of automatic braking by COP control stops when it is determined that there is an acceleration operation by the driver.
That is, as shown in FIG. 10, a part of the processing of the COP control unit 101 is different. The same processing blocks as those in the first embodiment will be described with the same reference numerals.
The COP control unit 101 according to the second embodiment determines that the COP operation is performed in Step S180, and substitutes “1” for the COP operation flag COP in Step S190, and then proceeds to Step S500.
[0035]
In step S500, the presence or absence of the driver's intention to accelerate is determined from the accelerator flag or the like, and when it is determined that the driver has performed an acceleration operation as the intention to accelerate, the process proceeds to step S510. On the other hand, when it is determined that the acceleration operation has not been performed, the processing from step S240 to step S300 is performed, and an automatic braking operation for ensuring stable turning is performed. Step S500 is an acceleration intention detection unit constituting acceleration intention detection means.
When it is determined that the acceleration operation is being performed and the process proceeds to step S510, after the completion process of the COP operation is performed, the correction value α is calculated in steps S200 and S210 as in the first embodiment, and then the process returns. .
Other processes are the same as those in the first embodiment.
[0036]
Next, in this embodiment, when it is determined that the driver intends to accelerate, the automatic braking process by COP control is stopped. At this time, the TCS control operation intervention is reduced by lowering the TCS control operation threshold. Will be early. As a result, since the automatic braking is stopped by the COP control together with the acceleration operation, even if the driving wheel accelerates and slips early, the acceleration slip can be suppressed early, that is, the lateral force of the driving wheel is secured and the vehicle Stability can be increased. When the acceleration slip is suppressed and the operation of the TCS control is stopped, the operation threshold value of the TCS control returns to the initial value.
[0037]
As a result, in order for the driver to perform accelerator control suitable for the behavior state of the vehicle, it is possible to reflect the driver's intention, and it is possible to eliminate a sense of incongruity such as poor acceleration (a feeling of stall).
FIG. 11 shows a time chart example in the second embodiment. Even if the driver determines that he has an intention to accelerate and stops the operation of the COP control, the early intervention of the TCS control is performed and the slip converges early. A broken line is an example when the operation threshold value of TCS control is fixed to ΔVt.
Other operations and effects are the same as those in the first embodiment.
[Brief description of the drawings]
FIG. 1 is a diagram showing a system configuration according to an embodiment of the present invention.
FIG. 2 is a system diagram showing a hydraulic system according to the first embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of a controller according to an embodiment of the present invention.
FIG. 4 is a diagram showing a processing flow of a COP control unit according to the first embodiment based on the present invention.
FIG. 5 is a diagram showing a relationship between a lateral acceleration (a turning state amount) and a correction value α.
FIG. 6 is a conceptual diagram showing a correction image of a correction value α according to a change state of a turning direction.
FIG. 7 is a diagram showing a process flow of a TCS control unit according to the first embodiment of the present invention.
FIG. 8 is a diagram showing the relationship between the longitudinal force and lateral force and the slip ratio of the drive wheel.
FIG. 9 is a diagram showing an example time chart according to the first embodiment of the present invention.
FIG. 10 is a diagram showing a processing flow of a COP control unit according to a second embodiment based on the present invention.
FIG. 11 is a diagram showing a time chart example according to a second embodiment based on the present invention.
[Explanation of symbols]
14 Controller 100 TCS control unit 100A Acceleration slip detection unit 100B Acceleration slip operation threshold value calculation unit 100C TCS operation intervention determination unit 100D Traction reduction unit 101 COP control unit 101A Turning state detection unit 101B Turning limit calculation unit 101C COP operation intervention determination unit 101D Braking Unit 102 Operation threshold setting change means 103 Acceleration intention detection unit ΔVt TCS control operation threshold (basic value)
ΔVtcs TCS control threshold (corrected value)
α correction value

Claims (4)

When an acceleration slip of a driving wheel is detected and it is determined that the acceleration slip amount is equal to or greater than a predetermined operation threshold value, a vehicle equipped with acceleration slip suppression control means for applying braking force for reducing acceleration slip or controlling driving force suppression is provided. In the behavior control device,
In accordance with the turning state of the vehicle by correcting the operating threshold for the acceleration slip quantity, provided with actuation threshold setting changing means for correcting a small value the operating threshold for the more the acceleration slip quantity turning state is increased,
The operation threshold setting change means corrects the operation threshold for the acceleration slip amount according to a change state of the turning state of the vehicle, and corrects the operation threshold to a small value when the turning state changes in a direction in which the turning state becomes stronger. A vehicle behavior control device. Automatic deceleration control means for automatically applying a braking force to the vehicle when it is determined that the behavior state of the vehicle exceeds a predetermined turning state amount;
Acceleration slip suppression control means for detecting acceleration slip of the drive wheel and controlling the control of the braking force and the braking force for reducing the acceleration slip when the acceleration slip amount is determined to be equal to or greater than a predetermined operation threshold. In the vehicle behavior control device,
When it is determined that the behavior state of the vehicle exceeds the strength of the predetermined turning state, the vehicle is provided with an operation threshold setting change means for correcting the operation threshold for the acceleration slip amount to a small value ,
The operation threshold setting change means corrects the operation threshold for the acceleration slip amount according to a change state of the turning state of the vehicle, and corrects the operation threshold to a small value when the turning state changes in a direction in which the turning state becomes stronger. A vehicle behavior control device. The operation threshold setting change means realizes correction for reducing the operation threshold based on the strength of the turning state by subtracting the correction value from the operation threshold, and the turning state of the vehicle is strengthened. In this case, by adding a value obtained by multiplying the rate of change of the turning state over time by a predetermined coefficient to the correction value, the operation threshold value is decreased when the turning state changes in a stronger direction. When the vehicle turning state is weakened, the turning state is changed in the direction of weakening by subtracting the value obtained by multiplying the rate of change of the turning state over time by a predetermined coefficient from the correction value. The behavior control apparatus for a vehicle according to claim 1 or 2, wherein the operation threshold value is corrected to a large value. Acceleration intention detection means for detecting the driver's acceleration operation and detecting the driver's acceleration intention is provided, and the automatic deceleration control means determines the automatic braking load when the driver determines that the acceleration operation is being performed. 4. The vehicle behavior control device according to claim 2, wherein the operation control is stopped.

Images