JP3730727B2 - Vehicle yaw moment control device - Google Patents

Description

【００４１】
尚、車両の直進走行中に加速或いは減速を行っても、車両のヨーモーメントは変化しないため、第１油圧クラッチ３_L 及び第２油圧クラッチ３_R は非係合状態に保たれる。
【００４２】
ところで、駆動輪である後輪Ｗ_RL，Ｗ_RRがタイヤのグリップ力の限界付近で旋回を行っているとき、ドライバーが車両を加速すべくアクセルペダルを更に踏み込んだ場合、前述した理由によって後輪Ｗ_RL，Ｗ_RRが発生するコーナリングフォースＣＦｆが実際に必要なコーナリングフォースを下回ってしまい、車両の後部が旋回外側に振られてオーバーステア傾向が強まってしまう場合がある。このとき、（１７）式で与えられるクラッチトルクＴは、前述した後輪Ｗ_RL，Ｗ_RRのコーナリングフォースＣＦｆの不足に起因するヨーモーメントを考慮していないため、前述したオーバーステア傾向の発生を補償することはできない。
【００４３】
そこで、（１７）式における無次元化前後加速度Ｘｇ及び無次元化横加速度Ｙｇに代えて、後輪Ｗ_RL，Ｗ_RRのコーナリングフォースＣＦｆの不足に起因するヨーモーメントを考慮した（１）式の無次元化補正前後加速度Ｘｇ′及び（２）式の無次元化補正横加速度Ｙｇ′を用いれば、つまり、クラッチトルクＴを、
Ｔ＝｛２Ｒ／（ｔｒ×κ）｝×ｈｇ×Ｗ×Ｘｇ′×Ｙｇ′ …（１８）
により算出すれば、旋回中における前記オーバーステア傾向を補償することができる。
【００４４】
これを更に説明すると、図５（Ａ），（Ｂ）における破線は（１）式及び（２）式の右辺第１項（無次元化前後加速度Ｘｇ及び無次元化横加速度Ｙｇの一次の項）に、また鎖線は（１）及び（２）式の右辺第２項（無次元化前後加速度Ｘｇ或いは無次元化横加速度Ｙｇの三次の項）にそれぞれ対応しており、破線の値から鎖線の値を減算した実線の値が無次元化補正前後加速度Ｘｇ′及び無次元化補正横加速度Ｙｇ′に対応している。従来例に相当する（１７）式は、（１）式及び（２）式の右辺第２項の三次の項を削除したものに相当しており、それに三次の項を付加すると、本発明に相当する（１８）式を得ることができる。本発明によれば、前後加速度Ｘｇ×Ｇ或いは横加速度Ｙｇ×Ｇの増加に応じて前記三次の項に相当する量だけクラッチトルクＴの増加が抑制され、それに伴って左右の後輪Ｗ_RL，Ｗ_RR間のトルク配分量が少なめに増加するため、後輪Ｗ_RL，Ｗ_RRのコーナリングフォースＣＦｆの不足により発生するヨーモーメントを打ち消してオーバーステア傾向の発生を防止することができる。
【００４５】
図６は本発明の第２実施例を示すものである。第１実施例では無次元化補正前後加速度Ｘｇ′及び無次元化補正横加速度Ｙｇ′を、（１）式及び（２）式により無次元化前後加速度Ｘｇ及び無次元化横加速度Ｙｇの関数として設定しているが、第２実施例では無次元化補正前後加速度Ｘｇ′及び無次元化補正横加速度Ｙｇ′を、無次元化前後加速度Ｘｇ及び無次元化横加速度Ｙｇをパラメータとするテーブルにより設定している。この第２実施例においても、トルク配分量を前後加速度Ｘｇ×Ｇ或いは横加速度Ｙｇ×Ｇに正比例する値よりも少なく増加させるので、車両の旋回中におけるオーバーステア傾向を補償して安定した旋回を可能にすることができる。
【００４６】
以上、本発明の実施例を詳述したが、本発明はその要旨を逸脱しない範囲で種々の設計変更を行うことが可能である。
【００４７】
例えば、実施例では従動輪である左右の前輪Ｗ_FL，Ｗ_FR間のトルク配分について説明したが、本発明は駆動輪である左右の後輪Ｗ_RL，Ｗ_RR間のトルク配分に対しても適用することができる。また、第１油圧クラッチ３_L 及び第２油圧クラッチ３_R に代えて、電磁クラッチや流体カップリング等の他のクラッチを用いることができる。更に、実施例ではクラッチトルクＴを無次元化補正前後加速度Ｘｇ′及び無次元化補正横加速度Ｙｇ′の積Ｘｇ′×Ｙｇ′の関数として設定しているが、無次元化補正前後加速度Ｘｇ′だけの関数として或いは無次元化補正横加速度Ｙｇ′だけの関数として設定しても、充分な作用効果を得ることができる。
【００４８】
【発明の効果】
以上のように、請求項１に記載された発明によれば、車両のヨーモーメント制御装置が、左右の前輪間及び／又は左右の後輪間をギヤ列及びトルク伝達クラッチで相互に接続し、左右一方の車輪を増速することにより該一方の車輪に駆動力を発生させるとともに、左右他方の車輪を減速することにより該他方の車輪に制動力を発生させるトルク配分手段と、トルク配分手段を制御して、車両が旋回中に加速するときは旋回内輪を減速することにより旋回内輪に制動力を発生させるとともに、旋回外輪を増速することにより旋回外輪に駆動力を発生させ、且つこのトルク配分量を車両の前後加速度に応じて増加させるトルク配分量決定手段とを備えており、前記トルク配分量決定手段は、トルク配分量を前後加速度に正比例する値よりも少なく増加させるので、車両の前後加速度の増加に応じて意図せぬオーバーステア傾向になっても、そのオーバーステア傾向を補償して安定した旋回を可能にすることができる。
【００４９】
また請求項２に記載された発明によれば、車両のヨーモーメント制御装置が、左右の前輪間及び／又は左右の後輪間をギヤ列及びトルク伝達クラッチで相互に接続し、左右一方の車輪を増速することにより該一方の車輪に駆動力を発生させるとともに、左右他方の車輪を減速することにより該他方の車輪に制動力を発生させるトルク配分手段と、トルク配分手段を制御して、車両が旋回中に加速するときは旋回内輪を減速することにより旋回内輪に制動力を発生させるとともに、旋回外輪を増速することにより旋回外輪に駆動力を発生させ、且つこのトルク配分量を車両の横加速度に応じて増加させるトルク配分量決定手段とを備えており、前記トルク配分量決定手段は、トルク配分量を横加速度に正比例する値よりも少なく増加させるので、車両の横加速度の増加に応じて意図せぬオーバーステア傾向になっても、そのオーバーステア傾向を補償して安定した旋回を可能にすることができる。
【図面の簡単な説明】
【図１】 トルク配分制御装置を備えたミッドエンジン・リヤドライブ車の全体構成図
【図２】 電子制御ユニットの回路構成を示すブロック図
【図３】 旋回中の車両に発生するヨーモーメントを説明する図
【図４】 油圧クラッチの係合に基づいて発生するヨーモーメントを説明する図
【図５】 補正前後加速度Ｘｇ′及び補正横加速度Ｙｇ′を示すグラフ
【図６】 本発明の第２実施例に係る、前記図５に対応する図
【符号の説明】
２ 変速機（トルク配分手段）
３ _L 第１油圧クラッチ（トルク配分クラッチ）
３ _R 第２油圧クラッチ（トルク配分クラッチ）
７ 第１ギヤ（ギヤ列）
８ 第２ギヤ（ギヤ列）
９ 第３ギヤ（ギヤ列）
１０ 第４ギヤ（ギヤ列）
１１ 第５ギヤ（ギヤ列）
１２ 第６ギヤ（ギヤ列）
２０ 前後加速度算出手段
２１ 横加速度算出手段
２２ トルク配分量決定手段
Ｗ_FL 前輪
Ｗ_FR 前輪
Ｗ_RL 後輪
Ｗ_RR 後輪
Ｘｇ×Ｇ 前後加速度
Ｙｇ×Ｇ 横加速度[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a yaw moment control device for a vehicle that changes steering characteristics by distributing different torques to left and right wheels.
[0002]
[Prior art]
  In the vehicle, the left and right wheels of the vehicle are connected to each other by a transmission and a torque transmission clutch, the driving force is generated on one of the left and right wheels, and the braking force is generated on the other wheel on the left and right. This application cancels an undesirable yaw moment that occurs when a turning vehicle accelerates or decelerates by setting the distribution of driving force and braking force as a function of the product of the longitudinal acceleration and lateral acceleration of the vehicle. It has already been proposed by a person (see Japanese Patent Application No. 7-247336).
[0003]
[Problems to be solved by the invention]
  By the way, as is known as the theory of tire friction circles, the grip force acting on the tire contact surface is broken down into a longitudinal driving force (braking force) and a lateral cornering force, and the resultant force is The static friction force on the ground contact surface is not exceeded. Therefore, for example, when the rear wheel drive vehicle is turning near the limit of the grip force of the tire, if the driving force is applied to the rear wheel as the drive wheel to increase the longitudinal acceleration, the cornering force of the rear wheel is accordingly increased. Will be reduced. Since the vehicle during turning maintains stability around the yaw axis by the balance between the cornering force of the front wheels and the cornering force of the rear wheels, the rear portion of the vehicle is swung to the outside of the turn due to the decrease in the cornering force of the rear wheels described above. There is a problem that the oversteer tendency becomes stronger. In particular, when the grip force of the tire reaches the limit and the slip ratio increases, the driving force decreases gradually, whereas the cornering force decreases rapidly, and thus the oversteer tendency appears remarkably.
[0004]
  The present invention has been made in view of the above-described circumstances, and an object thereof is to accurately compensate for an oversteer tendency generated in a rear-wheel drive vehicle that is turning.
[0005]
[Means for Solving the Problems]
  In the invention described in claim 1,Torque distribution means that connects the left and right wheels of a rear-wheel drive vehicle with a gear train and a torque transmission clutch. When the vehicle accelerates while turning, it generates braking force on the turning inner wheel by decelerating the turning inner wheel. In addition, the driving force is generated in the turning outer wheel by increasing the speed of the turning outer wheel, and the torque distribution amount is increased in accordance with the longitudinal acceleration of the vehicle.In this case, since the torque distribution amount is increased less than a value that is directly proportional to the longitudinal acceleration, the cornering force of the rear wheel is reduced according to the increase of the longitudinal acceleration of the vehicle, that is, the increase of the driving force of the rear wheel, Even if the vehicle has an unintended oversteer tendency, it can be compensated by slightly increasing the torque distribution amount that distributes the oversteer tendency to the left and right wheels.
[0006]
  In the invention described in claim 2,Torque distribution means that connects the left and right wheels of a rear-wheel drive vehicle with a gear train and a torque transmission clutch. When the vehicle accelerates while turning, it generates braking force on the turning inner wheel by decelerating the turning inner wheel. In addition, the driving force is generated in the turning outer wheel by increasing the speed of the turning outer wheel, and the torque distribution amount is increased in accordance with the lateral acceleration of the vehicle.In this case, the torque distribution amount is increased less than a value that is directly proportional to the lateral acceleration, so that the cornering force generated by the rear wheels in response to the increase in the lateral acceleration of the vehicle is insufficient, and the vehicle has an unintended oversteer tendency. However, the oversteer tendency can be compensated by slightly increasing the torque distribution amount that is distributed to the left and right wheels.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings. 1 to 5 show a first embodiment of the present invention. FIG. 1 is an overall configuration diagram of a mid-engine / rear drive vehicle equipped with a torque distribution control device, and FIG. 2 is a circuit configuration of an electronic control unit. FIG. 3 is a block diagram, FIG. 3 is a diagram illustrating a yaw moment generated in a turning vehicle, FIG. 4 is a diagram illustrating a yaw moment generated based on engagement of a hydraulic clutch, and FIG. 5 is a corrected longitudinal acceleration Xg ′ and a corrected It is a graph which shows lateral acceleration Yg '.
[0008]
  As shown in FIG. 1, a transmission M is connected to the left end of an engine E mounted horizontally in the center of the vehicle body, and the left rear wheel W that is a driving wheel is driven by the engine E and the transmission M._RLAnd right rear wheel W_RRIs driven.
[0009]
  Front left wheel W which is driven wheel_FLAnd right front wheel W_FRAxle 1_L, 1_RBetween the left and right front wheels W_FL, W_FRAre connected so that they rotate at different rotational speeds. The transmission 2 constitutes the torque distribution means of the present invention, and the first hydraulic clutch 3_LAnd the second hydraulic clutch 3_RAnd the first hydraulic clutch 3_LAnd the left front wheel W_FLThe right front wheel W_FROf the second hydraulic clutch 3_RAnd the right front wheel W_FRLeft front wheel W_FLThe rotation speed is increased.
[0010]
  That is, the transmission 2 has left and right axles 1_L, 1_RA first shaft 4 arranged coaxially with the left and right axles 1_L, 1_RAnd the second shaft 5 and the third shaft 6 disposed coaxially with each other, and the first hydraulic clutch 3 is interposed between the second shaft 5 and the third shaft 6._LIs placed and the right axle 1_RAnd the second hydraulic clutch 3 between the first shaft 4 and the second hydraulic clutch 3_RIs placed. Right axle 1_RThe small-diameter first gear 7 provided on the second shaft 5 meshes with the large-diameter second gear 8 provided on the second shaft 5, and the small-diameter third gear 9 provided on the third shaft 6 is provided on the first shaft 4. It meshes with the fourth gear 10 having a large diameter. Left axle 1_LThe fifth gear 11 provided on the second gear meshes with the sixth gear 12 provided on the third shaft 6.
[0011]
  The first gear 7 and the third gear 9 have the same number of teeth, and the second gear 8 and the fourth gear 10 have the same number of teeth, and the first gear 7 and the third gear 9 have the same number of teeth. It is set to be more than that. The number of teeth of the fifth gear 11 and the sixth gear 12 is set to be the same.
[0012]
  Accordingly, the first hydraulic clutch 3_LAnd the right front wheel W_FRIs the right axle 1_R, First gear 7, second gear 8, second shaft 5, first hydraulic clutch 3_L, Third shaft 6, sixth gear 12, fifth gear 11 and left axle 1_LLeft front wheel W_FLConnected to At this time, according to the gear ratio of the first gear 7 and the second gear 8, the right front wheel W_FRLeft front wheel W_FLThe number of rotations is reduced. That is, the left and right front wheels W_FL, W_FRThe first hydraulic clutch 3 from the state that the motor is rotating at the same speed_LAnd the right front wheel W_FRThe left front wheel W_FLThe number of rotations is reduced.
[0013]
  The second hydraulic clutch 3_RAnd the right front wheel W_FRIs the right axle 1_R, Second hydraulic clutch 3_R, First shaft 4, fourth gear 10, third gear 9, third shaft 6, sixth gear 12, fifth gear 11 and left axle 1_LLeft front wheel W_FLConnected to At this time, the right front wheel W is applied to the fourth gear 10 and the third gear 9 according to the gear ratio._FRLeft front wheel W_FLThe number of revolutions is increased. That is, the left and right front wheels W_FL, W_FRThe second hydraulic clutch 3 from the state where the motor is rotating at the same speed_RAnd the right front wheel W_FRLeft front wheel W_FLThe number of revolutions is increased.
[0014]
  First hydraulic clutch 3_LAnd the second hydraulic clutch 3_RThe engagement force of the left and right front wheels W can be controlled steplessly by adjusting the magnitude of the hydraulic pressure applied to them._FL, W_FRThe rotation speed ratio can also be controlled steplessly within a range determined by the gear ratio of the first to fourth gears 7, 8, 9, and 10.
[0015]
  The electronic control unit U includes an engine speed sensor S that detects the speed of the engine E.₁And an intake pipe absolute pressure sensor S for detecting the absolute pressure in the intake pipe of the engine E₂And a steering angle sensor S for detecting the steering angle of the steering wheel 13_ThreeAnd a lateral acceleration sensor S for detecting the lateral acceleration of the vehicle body_FourAnd a wheel speed sensor S for detecting the rotational speeds of the four wheels in order to calculate the vehicle speed._FiveThe signal from is input.
[0016]
  As is apparent from FIG. 2, the electronic control unit U is provided with a longitudinal acceleration calculating means 20, a lateral acceleration calculating means 21, a torque distribution amount determining means 22 and a left / right turning determining means 23, and the longitudinal acceleration calculating means 20Is composed of a gear position determining means 24, a driving wheel torque calculating means 25, a rotational acceleration calculating means 26, a drive system inertia correcting means 27, and a running resistance correcting means 28, and a lateral acceleration calculating means 21Is composed of lateral acceleration estimating means 29, adding means 30, and average value calculating means 31, and torque distribution amount determining means 22 is composed of corrected longitudinal acceleration calculating means 32, corrected lateral acceleration calculating means 33, and control amount calculating means 34. .
[0017]
  The oil pumped up from the oil tank 14 by the oil pump 15 is regulated by a pressure regulating valve 16 comprising a linear solenoid valve, and a first on-off valve 17 comprising an ON / OFF valve._L1st hydraulic clutch 3_LAnd a second on-off valve 17 comprising an ON / OFF valve_R2nd hydraulic clutch 3_RTo be supplied. The electronic control unit U includes a first hydraulic clutch 3 of the transmission 2._LAnd the second hydraulic clutch 3_RLeft and right front wheels W_FL, W_FRIn order to generate a braking force on one side and a driving force on the other side, the output hydraulic pressure of the pressure regulating valve 16 is controlled, and the first on-off valve 17 is controlled._LAnd the second on-off valve 17_ROpen / close control.
[0018]
  Next, the longitudinal acceleration by the longitudinal acceleration calculating means 20Every timeThe calculation of will be described. The gear position determination means 24 is provided with an engine speed sensor S.₁Speed Ne detected by the wheel and wheel speed sensor S_FiveThe gear position of the transmission M is determined on the basis of the vehicle speed V detected in step S2. The drive wheel torque calculation means 25 is an intake pipe absolute pressure sensor S.₂The engine torque is calculated on the basis of the intake pipe absolute pressure Pb and the engine speed Ne detected in step S1, and the driving wheel torque is calculated by correcting the detected gear position based on the gear ratio i. The rotational acceleration detection means 26 detects the rotational acceleration of the drive system based on the vehicle speed V, the drive system inertia correction means 27 corrects the drive wheel torque by the rotational acceleration of the drive system, and the running resistance correction means 28 further detects the vehicle speed. By correcting the driving wheel torque with the running resistance detected based on V, the vehicle is finally accelerated in the longitudinal direction.Every timeIs calculated.
[0019]
  Next, the lateral acceleration by the lateral acceleration calculating means 21Every timeThe calculation of will be described.In the present specification, in order to simplify the following formula as much as possible, the dimensionless lateral acceleration Yg which is a numerical value indicating how many times the lateral acceleration is larger than the gravitational acceleration G and has no dimension. , Which is a numerical value indicating how many times the longitudinal acceleration is larger than the gravitational acceleration G, and the dimensionless longitudinal acceleration Xg having no dimension, and therefore, the lateral acceleration is expressed by “Yg × G”. The longitudinal acceleration is expressed by “Xg × G”.
[0020]
  Thus,The lateral acceleration estimating means 29 is provided with a steering angle sensor S._ThreeEstimated lateral acceleration Yg based on the steering angle θ and the vehicle speed V₁Search for a map. In the adding means 30, the estimated lateral acceleration Yg₁And lateral acceleration sensor S_FourActual lateral acceleration Yg detected by₂And the average value calculating means 31 multiplies the added value by 1/2.,Estimated lateral acceleration Yg₁And actual lateral acceleration sensor S_Four Actual lateral acceleration Yg detected by ₂ Lateral acceleration Yg which is the average value of× GIs calculated. Thus, the actual lateral acceleration Yg₂Estimated lateral acceleration Yg₁By correcting with, accurate lateral acceleration Yg without time delay× GCan be obtained.
[0021]
  Subsequently, the corrected longitudinal acceleration calculating means 32 of the torque distribution amount determining means 22Made dimensionless like XgCorrected longitudinal acceleration Xg 'DimensionlessIt is calculated based on the following equation as a function of the longitudinal acceleration Xg.
[0022]
                Xg ′ = A × Xg−B × Xg^Three                  ... (1)
  The right side of equation (1) is the sum of the first and third order terms of Xg, and A and B are preset positive constants. If the right side of equation (1) is only the primary term (A × Xg),DimensionlessThe corrected longitudinal acceleration Xg ′ isDimensionlessAlthough it increases in direct proportion to the increase in the longitudinal acceleration Xg, the third-order term (−B × Xg on the right side of the equation (1)^Three)DimensionlessThe corrected longitudinal acceleration Xg ′ isDimensionlessIt increases less than a value that is directly proportional to the longitudinal acceleration Xg.
[0023]
  Similarly, the corrected lateral acceleration calculating means 33 of the torque distribution amount determining means 22 isMade dimensionless like YgCorrected lateral acceleration Yg 'DimensionlessIt is calculated based on the following equation as a function of the lateral acceleration Yg.
[0024]
                Yg ′ = C × Yg−D × Yg^Three                  ... (2)
  The right side of the equation (2) is the sum of the primary term and the tertiary term of Yg, and C and D are preset positive constants. If the right side of equation (2) is only the primary term (C × Yg),DimensionlessThe corrected lateral acceleration Yg ′ isDimensionlessAlthough it increases in direct proportion to the increase in the lateral acceleration Yg, the cubic term (−D × Yg on the right side of the equation (2)).^Three)DimensionlessThe corrected lateral acceleration Yg ′ isDimensionlessIt increases less than a value that is directly proportional to the lateral acceleration Yg.
[0025]
  Then, the control amount calculation means 34 isDimensionlessCorrected longitudinal acceleration Xg ′ andDimensionlessAs a function of Xg ′ × Yg ′ multiplied by the corrected lateral acceleration Yg ′, the pressure regulating valve 16ofControl amount, that is, left and rightFront wheel W _FL , W _FR The amount of torque distributed between them is calculated.
[0026]
  Next, the operation of the embodiment of the present invention having the above-described configuration will be described.
[0027]
  3 shows weight W(Ie mass W / G)Vehicle is lateral acceleration Yg× GIndicates the left-turning state., The product of its mass (W / G) and lateral acceleration (Yg × G)Centrifugal force W × Yg is acting, and this centrifugal force W × Yg is,The cornering force CFf acting between the front wheel and the road surface and the cornering force CFr acting between the rear wheel and the road surface are balanced.
[0028]
                      W × Yg = CFf + CFr (3)
  If the distance between the center of gravity of the vehicle and the front wheel is a and the distance between the center of gravity and the rear wheel is b, the moment M around the yaw axis by the cornering forces CFf and CFr₁Is
                      M₁= A * CFf-b * CFr (4)
Given in.
[0029]
  By the way, when the vehicle is traveling straight ahead, the ground contact loads of the left and right wheels are the same, but when the vehicle turns, the ground load changes between the turning inner wheel and the turning outer wheel. That is, when the vehicle turns, a centrifugal force directed outward in the turning direction acts on the center of gravity of the vehicle body, so that the vehicle body tends to fall outward in the turning direction. As a result, the turning inner wheel tends to lift from the road surface, the grounding load of the turning inner wheel decreases, and the tendency of the turning outer wheel to be pressed against the road surface increases, so that the grounding load of the turning outer ring increases.
[0030]
  Further, the ground load on the front and rear wheels is constant when the vehicle is traveling at a constant speed, but the ground load on the front and rear wheels changes when the vehicle is accelerated or decelerated. That is, an inertial force acting toward the rear of the vehicle body acts on the center of gravity of the vehicle body during acceleration, so that the grounding load of the rear wheel increases as the vehicle body tries to tail dive, and as a result, the cornering force of the rear wheel increases and the direction opposite to the turning direction Moment M₁When the vehicle decelerates, an inertial force that acts toward the front of the vehicle body acts on the center of gravity of the vehicle body.Therefore, the vehicle's nose dive increases the ground load on the front wheels, resulting in an increase in the cornering force of the front wheels and the same turning direction. Directional moment M₁Acts (see solid line arrows and broken line arrows in FIG. 3).
[0031]
  When the vehicle is traveling at a constant speed in a straight line, if the sum of the ground contact loads of the left and right front wheels is Wf, the ground load of each front wheel is Wf / 2.× GLongitudinal acceleration Xg while turning at× GWhen the vehicle is accelerating / decelerating, the ground contact load W of the front wheel inside the turn_FIAnd the ground contact load W of the front wheel outside the turn_FOIs
              W_FI= Wf / 2-Kf * Yg-Kh * Xg (5)
              W_FO= Wf / 2 + Kf * Yg-Kh * Xg (6)
If the sum of the ground contact loads of the left and right rear wheels is Wr, the ground load W of the rear wheels inside the turn_RIAnd the ground contact load W of the rear wheel outside the turn_ROIs
              W_RI= Wr / 2-Kr * Yg + Kh * Xg (7)
              W_RO= Wr / 2 + Kr * Yg + Kh * Xg (8)
Given in. In the equations (5) to (8), the coefficients Kf, Kr, and Kh are given by the following equations.
[0032]
            Kf = (Gf ′ × hg ′ × W + hf × Wf) / tf (9)
            Kr = (Gr ′ × hg ′ × W + hr × Wr) / tr (10)
            Kh = hg × W / (2 × L) (11)
The symbols used here are as follows.
[0033]
                    Gf, Gr: Front wheel and rear wheel roll rigidity
                Gf ', Gr': Front wheel and rear wheel roll stiffness distribution
                            Gf ′ = Gf / (Gf + Gr)
                            Gr ′ = Gr / (Gf + Gr)
                    hf, hr: front wheel, rear wheel roll center height
                          hg: Center of gravity height
                        hg ': Distance between the center of gravity and the roll axis
                            hg ′ = hg− (hf × Wf + hr × Wr) / W tf, tr; front wheel, rear wheel tread
                            L: Wheel base
                                L = a + b
  Tire cornering force,Contact load of the tireAnd the product of dimensionless lateral acceleration YgAssuming that the cornering force CFf of the front wheel is the ground contact load W of the front wheel inside the turn given by equation (5)._FIAnd the ground contact load W of the front wheel outside the turn given by equation (6)_FOWhen,DimensionlessThe lateral acceleration Yg is given by the following equation.
[0034]
                  CFf = W_FI× Yg + W_FO× Yg
                        = Wf * Yg-2 * kh * Xg * Yg (12)
  Further, the cornering force CFr of the rear wheel is the ground contact load W of the rear wheel inside the turn given by the equation (7)._RIAnd the ground contact load W of the rear wheel outside the turn given by equation (8)_ROWhen,DimensionlessThe lateral acceleration Yg is given by the following equation.
[0035]
                  CFr = W_RI× Yg + W_RO× Yg
                        = Wr * Yg + 2 * kh * Xg * Yg (13)
  Substituting Equation (12) and Equation (13) into Equation (4),
              M₁= A * (Wf * Yg-2 * Kh * Xg * Yg)
                      −b × (Wr × Yg + 2 × Kh × Xg × Yg)
                  = (A * Wf-b * Wr) * Yg
                      -2 * Kh * L * Xg * Yg (14)
  Here, since a × Wf−b × Wr = 0 and Kh = hg × W / (2 × L) from the equation (11), the equation (14) is
                      M₁= −hg × W × Xg × Yg (15)
And the moment M around the yaw axis₁Is the longitudinal acceleration Xg× GAnd lateral acceleration Yg× GIt can be seen that it is proportional to the product of. Therefore, the moment M about the yaw axis given by equation (15)₁If the driving force and the braking force are distributed to the turning inner wheel and the turning outer wheel so as to cancel out the turning, it is possible to improve turning stability and high-speed stability during acceleration or deceleration during turning.
[0036]
  On the other hand, as shown in FIG. 4, for example, when the braking force F is generated in the turning inner wheel, if the gear ratio of the transmission 2 is i, the driving force is generated in the turning outer wheel as F / i. Moment M about the yaw axis generated in the vehicle by these braking force F and driving force F / i₂Is
                M₂= (Tr / 2) × F × κ
                    = (Tr / 2) × (T / R) × κ (16)
Given in. Here, κ = 1 + (1 / i), T: clutch torque, R: tire radius.
[0037]
  Therefore, moment M₂At moment M₁The clutch torque T required to cancel₁= M₂By putting
          T = {2R / (tr × κ)} × hg × W × Xg × Yg (17)
Given in. As apparent from the equation (17), the clutch torque T is a value proportional to the product of the longitudinal acceleration Xg and the lateral acceleration Yg. In the above description, the cornering force of the tire is the contact load of the tire.Is the product of dimensionless lateral acceleration YgSince the clutch torque T is assumed to be the longitudinal acceleration Xg× GAnd lateral acceleration Yg× GStrictly speaking, since the cornering force is not proportional to the ground load, the clutch torque T is actually set to the longitudinal acceleration Xg.× GAnd lateral acceleration Yg× GofproductShould be treated as a function of
[0038]
  Thus, as shown in Table 1, when the vehicle accelerates during the left turn, the first on-off valve 17 is determined by the left / right turn determination means 23._LAnd the output hydraulic pressure of the pressure regulating valve 16 is controlled by the control amount calculation means 34, whereby the first hydraulic clutch 3_LIs engaged with the clutch torque T given by equation (17), the rotational speed of the inner turning wheel is reduced to generate a braking force F, and the rotational speed of the outer turning wheel is increased to increase the driving force F / i. As a result, the moment M in the direction opposite to the turning direction based on the cornering force M₁Is canceled and the turning performance is improved. Similarly, when the vehicle accelerates during a right turn, the second hydraulic clutch 3_RIs engaged with the clutch torque T, the moment M based on the cornering force is the same as described above.₁Is canceled and the turning performance is improved.
[0039]
  When the vehicle decelerates while turning left, the second hydraulic clutch 3_RIs engaged with the clutch torque T given by equation (17), the rotational speed of the inner turning wheel is increased to generate a driving force F, and the rotational speed of the outer turning wheel is reduced to reduce the braking force F / i. As a result, the moment M in the same direction as the turning direction based on the cornering force is generated.₁Is canceled and high-speed stable performance is improved. Similarly, when the vehicle decelerates while turning right, the first hydraulic clutch 3_LIs engaged with the clutch torque T, the moment M based on the cornering force is the same as described above.₁Is canceled and high-speed stable performance is improved.
[0040]
[Table 1]

[0041]
  Note that even if acceleration or deceleration is performed while the vehicle is traveling straight, the yaw moment of the vehicle does not change, so the first hydraulic clutch 3_LAnd the second hydraulic clutch 3_RIs kept in a disengaged state.
[0042]
  By the way, the rear wheel W which is a drive wheel_RL, W_RRWhen the vehicle is turning near the limit of the grip force of the tire, if the driver further depresses the accelerator pedal to accelerate the vehicle, the rear wheel W_RL, W_RRIn some cases, the cornering force CFf in which the occurrence of the phenomenon occurs falls below the cornering force that is actually required, and the rear portion of the vehicle is swung to the outside of the turn and the oversteer tendency is increased. At this time, the clutch torque T given by the equation (17) is equal to the rear wheel W described above._RL, W_RRSince the yaw moment resulting from the shortage of the cornering force CFf is not taken into consideration, the occurrence of the above-described oversteer tendency cannot be compensated.
[0043]
  Therefore, in equation (17)DimensionlessLongitudinal acceleration Xg andDimensionlessInstead of lateral acceleration Yg, rear wheel W_RL, W_RRIn consideration of yaw moment due to lack of cornering force CFfDimensionlessCorrected longitudinal acceleration Xg 'and equation (2)DimensionlessIf the corrected lateral acceleration Yg ′ is used, that is, the clutch torque T is
      T = {2R / (tr × κ)} × hg × W × Xg ′ × Yg ′ (18)
Can be compensated for the oversteer tendency during turning.
[0044]
  To explain this further, the broken lines in FIGS. 5A and 5B indicate the first term (1) on the right side of the equations (1) and (2).DimensionlessLongitudinal acceleration Xg andDimensionlessThe first term of the lateral acceleration Yg), and the chain line is the second term on the right side of the equations (1) and (2) (DimensionlessLongitudinal acceleration Xg orDimensionlessCorresponding to the cubic term of the lateral acceleration Yg), and the solid line value obtained by subtracting the chain line value from the broken line value isDimensionlessCorrected longitudinal acceleration Xg ′ andDimensionlessThis corresponds to the corrected lateral acceleration Yg ′. The expression (17) corresponding to the conventional example corresponds to the expression in which the third-order term of the second term on the right side of the expressions (1) and (2) is deleted. The corresponding equation (18) can be obtained. According to the present invention, the longitudinal acceleration Xg× GOr lateral acceleration Yg× GThe increase in the clutch torque T is suppressed by an amount corresponding to the third-order term in accordance with the increase in the left and right rear wheels W._RL, W_RRBecause the torque distribution amount increases slightly, the rear wheel W_RL, W_RRIt is possible to prevent the occurrence of an oversteer tendency by canceling the yaw moment generated due to the lack of the cornering force CFf.
[0045]
  FIG. 6 shows a second embodiment of the present invention. In the first embodimentDimensionlessCorrected longitudinal acceleration Xg ′ andDimensionlessThe corrected lateral acceleration Yg ′ is calculated using the equations (1) and (2).DimensionlessLongitudinal acceleration Xg andDimensionlessAlthough it is set as a function of the lateral acceleration Yg, in the second embodimentDimensionlessCorrected longitudinal acceleration Xg ′ andDimensionlessCorrected lateral acceleration Yg ′DimensionlessLongitudinal acceleration Xg andDimensionlessIt is set by a table using the lateral acceleration Yg as a parameter. Also in the second embodiment, the torque distribution amount is set to the longitudinal acceleration Xg.× GOr lateral acceleration Yg× GTherefore, it is possible to compensate for the oversteer tendency during turning of the vehicle and to enable stable turning.
[0046]
  As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.
[0047]
  For example, in the embodiment, the left and right front wheels W which are driven wheels_FL, W_FRIn the present invention, the left and right rear wheels W, which are drive wheels, are described._RL, W_RRIt can also be applied to the torque distribution between. The first hydraulic clutch 3_LAnd the second hydraulic clutch 3_RInstead, other clutches such as an electromagnetic clutch and a fluid coupling can be used. Further, in the embodiment, the clutch torque T is set toDimensionlessCorrected longitudinal acceleration Xg ′ andDimensionlessIt is set as a function of the product Xg ′ × Yg ′ of the corrected lateral acceleration Yg ′.DimensionlessAs a function of only the corrected longitudinal acceleration Xg 'orDimensionlessEven if it is set as a function of only the corrected lateral acceleration Yg ′, a sufficient effect can be obtained.
[0048]
【The invention's effect】
  As described above, according to the invention described in claim 1,The vehicle yaw moment control device connects the left and right front wheels and / or the left and right rear wheels to each other by a gear train and a torque transmission clutch, and accelerates one of the left and right wheels, thereby driving the one wheel. And the torque distribution means for generating braking force on the other wheel by decelerating the other wheel on the left and right sides, and the torque distribution means are controlled to decelerate the inner turning wheel when the vehicle accelerates during turning. Torque generating amount determining means for generating braking force on the inner turning wheel, generating driving force on the outer turning wheel by increasing the speed of the turning outer wheel, and increasing this torque distribution amount according to the longitudinal acceleration of the vehicle AndThe torque distribution amount determining means increases the torque distribution amount to be less than a value that is directly proportional to the longitudinal acceleration. Compensating can enable stable turning.
[0049]
  According to the invention described in claim 2,The vehicle yaw moment control device connects the left and right front wheels and / or the left and right rear wheels to each other by a gear train and a torque transmission clutch, and accelerates one of the left and right wheels, thereby driving the one wheel. And the torque distribution means for generating braking force on the other wheel by decelerating the other wheel on the left and right sides, and the torque distribution means are controlled to decelerate the inner turning wheel when the vehicle accelerates during turning. Torque generating amount determining means for generating a braking force on the inner turning wheel and generating a driving force on the outer turning wheel by accelerating the turning outer wheel and increasing the torque distribution amount according to the lateral acceleration of the vehicle. AndThe torque distribution amount determining means increases the torque distribution amount to be less than a value that is directly proportional to the lateral acceleration. Compensating can enable stable turning.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a mid-engine rear drive vehicle equipped with a torque distribution control device.
FIG. 2 is a block diagram showing a circuit configuration of an electronic control unit
FIG. 3 is a diagram for explaining a yaw moment generated in a turning vehicle.
FIG. 4 is a diagram for explaining a yaw moment generated based on engagement of a hydraulic clutch.
FIG. 5 is a graph showing corrected longitudinal acceleration Xg ′ and corrected lateral acceleration Yg ′.
FIG. 6 is a diagram corresponding to FIG. 5 according to the second embodiment of the present invention.
[Explanation of symbols]
2 Transmission (torque distribution means)
3 _L         1st hydraulic clutch (torque distribution clutch)
3 _R         Second hydraulic clutch (torque distribution clutch)
7          1st gear (gear train)
8          Second gear (gear train)
9          3rd gear (gear train)
10        4th gear (gear train)
11        5th gear (gear train)
12        6th gear (gear train)
20 Longitudinal acceleration calculation means
21 Lateral acceleration calculation means
22 Torque distribution amount determining means
W_FL        front wheel
W_FR        front wheel
W_RL        Rear wheel
W_RR        Rear wheel
Xg× G    Longitudinal acceleration
Yg× G    Lateral acceleration

Claims (2)

Left and right rear wheels (W _RL , W _RR ) as drive wheels,
Left and right front wheels (W _FL , W _FR ) as driven wheels,
The left and right front wheels (W _FL , W _FR ) and / or the left and right rear wheels (W _FL , W _FR ) are connected to each other by a gear train (7 to 12) and a torque transmission clutch (3 _L , 3 _R ). Torque distribution means (2) for generating a driving force on the one wheel by increasing the speed of one of the left and right wheels and generating a braking force on the other wheel by decelerating the other wheel on the left and right ;
Longitudinal acceleration calculation means (20) for calculating longitudinal acceleration (Xg × G ) of the vehicle;
When the vehicle is accelerated during turning by controlling the torque distribution means (2), the inner turning wheel is decelerated to generate a braking force on the turning inner wheel, and the turning outer wheel is accelerated to drive the turning outer wheel. And a torque distribution amount determining means (22) for increasing the torque distribution amount according to the longitudinal acceleration of the vehicle ,
In a vehicle yaw moment control device equipped with
The yaw moment control device for a vehicle, wherein the torque distribution amount determining means (22) increases the torque distribution amount to be less than a value directly proportional to the longitudinal acceleration (Xg × G ). Left and right rear wheels (W _RL , W _RR ) as drive wheels,
Left and right front wheels (W _FL , W _FR ) as driven wheels,
The left and right front wheels (W _FL , W _FR ) and / or the left and right rear wheels (W _FL , W _FR ) are connected to each other by a gear train (7 to 12) and a torque transmission clutch (3 _L , 3 _R ). Torque distribution means (2) for generating a driving force on the one wheel by increasing the speed of one of the left and right wheels and generating a braking force on the other wheel by decelerating the other wheel on the left and right ;
Lateral acceleration calculating means (21) for calculating the lateral acceleration (Yg × G ) of the vehicle;
When the vehicle is accelerated during turning by controlling the torque distribution means (2), the inner turning wheel is decelerated to generate a braking force on the turning inner wheel, and the turning outer wheel is accelerated to drive the turning outer wheel. And a torque distribution amount determining means (22) for increasing the torque distribution amount according to the lateral acceleration of the vehicle ,
In a vehicle yaw moment control device equipped with
The yaw moment control device for a vehicle, wherein the torque distribution amount determining means (22) increases the torque distribution amount less than a value directly proportional to the lateral acceleration (Yg × G ).

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