JP2009520635A - Vehicle roll control system - Google Patents

Abstract

  The present invention relates to a method of controlling an active anti-roll system for a motor vehicle that includes an actuator that acts on the rigidity of an anti-roll bar at the front and rear axle levels and that is controlled by an ECU in accordance with the lateral acceleration of the vehicle. The total anti-roll torque to be applied to the front and rear axles is determined, and the total anti-roll torque is calculated in such a way that one of the two inner rings at the time of rotation is applied with a minimum load that prevents its lifting. It is derived from the optimal rigidity distribution between the axles, and corresponds to a desired set point determined according to the lateral acceleration, speed and static gain of the vehicle during steering operation. It relates to a control method.

Description

  The present invention aims to improve the behavior of a vehicle, and thus to improve the driver's safety and driving comfort, and a vehicle for reducing the risk that one of the inner wheels is lifted during cornering and the vehicle overturns. The present invention relates to an active anti-roll system control method and control system.

  The motor vehicle is designed to behave as stably as possible regardless of the operation by the driver, particularly steering-related operations, or the grip state of the road surface. However, certain driving situations can cause one or both of the inner wheels to rise during cornering, often leading to a rollover of the vehicle. Such a situation is more likely as the center of gravity of the vehicle is higher and the tread, which is the distance between two wheels on the same axle, is narrower.

The anti-roll system makes it possible, among other things, to improve the behavior of the vehicle in such subtle situations, such as curves. For this purpose, the anti-roll system generally comprises an ECU (electronic control unit) that receives information about the lateral acceleration γ _T of the vehicle from a sensor and receives information about the speed of the wheel that can determine the speed V of the vehicle from another sensor. The anti-roll system also includes an actuator that can affect the stiffness of the suspension disposed between the chassis and each of the four wheels or the stiffness of the anti-roll bar at the front and rear axle levels. These actuators can include hydraulic or electric cylinders that can change the stiffness of the suspension, or stiffness-controlled active suspension elements.

  Current solutions for reducing the risk of wheel lift and even risk of rolling over the vehicle are described, for example, in European Patent Application EP0376306B1 filed with TOYOTA as the applicant. This solution utilizes a controlled suspension system. Such a system is too cost-effective to be considered interesting.

  The aim of the present invention is to control the active anti-roll system so as to reduce the risk that the wheels will lift off the road surface and the risk that the vehicle will roll over.

  To this end, the first object of the present invention is to actuate the anti-roll bar stiffness at the front and rear axle levels, and in particular to provide an active anti-active vehicle for motor vehicles comprising an actuator controlled by the ECU in accordance with the lateral acceleration of the vehicle. In the control method of the roll system, determine the total anti-roll torque to be applied to the front and rear axles, so that the total anti-roll torque has a minimum load on one of the two inner rings during cornering to prevent its lifting. It is derived from the optimal stiffness distribution between the two axles calculated and corresponds to the desired set point determined according to the lateral acceleration, speed and static gain of the vehicle during steering. It is a control method characterized by being.

  According to another feature, in order to prevent the front inner ring or the rear inner ring from lifting on the curve, the method provides a rigidity to the front axle or the rear axle that applies a minimum load to the front inner ring or the rear inner ring. The maximum value of the distribution is calculated according to the lateral and longitudinal accelerations of the vehicle.

  According to another feature, in the case of a two-axle active anti-roll system, the total anti-roll torque determined is the optimal stiffness distribution corresponding to one of the two front and rear inner wheels, the vehicle lateral acceleration, Distributed between the front and rear axles according to the optimal stiffness distribution obtained by saturating the stiffness distribution set point as a function of speed and static gain with the maximum value of the distribution to prevent wheel lift. The

  According to another characteristic, in the case of a single axle active anti-roll system acting on the rear axle, the determined total anti-roll torque is the optimal rear stiffness distribution corresponding to one of the two front and rear inner rings. Applied to the rear axle according to the optimal stiffness distribution of the rear, obtained by saturating the stiffness distribution set point determined according to the vehicle's lateral acceleration, speed and static gain with the maximum value to prevent wheel lift .

  According to another feature, in the case of a single axle active anti-roll system acting on the front axle, the total anti-roll torque determined is the optimal rear stiffness distribution corresponding to one of the two front and rear inner rings. It is added to the front axle in accordance with the optimal rear stiffness distribution obtained from the front stiffness distribution set point saturated with the maximum stiffness distribution to prevent wheel lift.

The second object of the present invention is to provide a control device for an active anti-roll system for a vehicle including an ECU that controls an actuator that acts on the rigidity of the anti-roll bar.
-Means for calculating the maximum distribution of rigidity applied to the two axles of the vehicle so that the subject inner ring receives a minimum load that prevents the inner ring from lifting off the road surface, and at the input part the vehicle's longitudinal acceleration and Means for receiving lateral acceleration;
-Means for calculating the total anti-roll torque setpoint applied to the actuator of the anti-roll system;
-Means for preventing the subject front inner ring or rear inner ring from lifting, means for calculating saturation torque distributed to the front or rear active anti-roll bar;
It is provided with the control apparatus characterized by the above-mentioned.

  According to another feature of the control system for a two-axle active anti-roll system for a vehicle, means for calculating the total anti-roll torque setpoint applied to the actuator of the anti-roll system are provided on the front and rear axles of the vehicle. Also calculate the distribution setpoint of added stiffness.

According to another feature of the control device for a two-axle active anti-roll system for a vehicle, the means for preventing the inner ring from lifting is
-The function of saturating the stiffness distribution set point between the front and rear axles with the maximum distribution calculated to prevent the front or rear inner ring from lifting up, between the upper and lower load distribution limits at the output; A function to send a saturation value;
-Multiplication function that multiplies the saturation value of the stiffness distribution set point by the anti-roll torque set point and sends the torque set point, and multiplies the stiffness distribution to the front axle by the anti-roll torque set point. The multiplication function combined with the multiplication giving the front torque set point,
Fulfill each.

According to another feature of the control device for the single axle active anti-roll system for the vehicle, the maximum distribution for preventing the rear inner ring from lifting and the total anti-roll torque set point are received at the input from the calculation means. The inner ring lift prevention means
-A function to calculate the absolute value of all torque setpoints;
-The ability to correlate the absolute value of all its torque set points with the absolute value of the stiffness distribution set point between the front and rear axles characteristic of the vehicle and determined by mapping during vehicle development;
-A function to saturate the anti-roll stiffness distribution, comparing the maximum distribution value with the setpoint value obtained by mapping, and if the distribution setpoint is less than the maximum distribution, all torque setpoints applied to the rear axle A function that takes the set point into account in the calculation and, when the set point is greater than the maximum distribution, replaces the set point with the maximum distribution to obtain the total torque,
The function of calculating the total torque sent to the rear axle actuator by reversing the load distribution versus torque curve and then multiplying by ± 1 depending on the sign of the total torque set point;
Fulfill each.

  According to another feature of the control system for the two-axle active anti-roll system for vehicles, in the prevention of the front wheel lift when there is an anti-roll system on the rear axle, the saturation function reduces the maximum stiffness of the front. Taking into account, the value of the rear stiffness is derived therefrom and compared to the desired distribution set point obtained from the total torque set point.

  Other features and advantages of the present invention will become apparent upon reading the description of the two embodiments of the present invention shown in the following figures.

  The present invention should be added to each of the two axles according to a defined distribution, in the case of both axle anti-roll systems, or a single axle system, in order to prevent lifting of one of the vehicle wheels that is inside when cornering In this case, the optimum total anti-roll torque to be applied to one of the two axles is calculated.

As shown in FIG. 1, in the case of a control device for a two-axle anti-roll system for a vehicle, whether the device is measured by a sensor or estimated, the longitudinal acceleration γ _{L of the} vehicle and the lateral direction The acceleration γ _T is received at the input unit.

When the longitudinal acceleration is estimated by the observer from the vehicle speed V and the braking request corresponding to the force F _f given by the driver, the longitudinal acceleration γ _L is obtained by dividing the force F _f by the maximum weight M _max of the vehicle. Represented by the quotient. That is,

  In order to evaluate the load movement lower, it is preferable to evaluate the signal lower.

The observer models the error d regarding acceleration as follows.

Parameters k ₁ and k ₂ are a trade-off between quickness of derivation and noise sensitivity.

When the lateral acceleration is estimated using two wheel models, the model uses the average steering angle α of the front axle and the vehicle speed V by applying them to the following equation.

はそのヨー速度、Ｉ_ｚはその重心を通る垂直軸の周りでのその慣性、Ｌ_１およびＬ_２は重心から前後それぞれの車軸までの距離、αはフロントアクスルの平均操舵角、Ｄ_１およびＤ_２はフロントおよびリアそれぞれのアクスルの偏流剛性(drift stiffness)、δは偏流角(drift angle)をそれぞれ示す。 In these equations, M is the total weight of the vehicle, V is its speed,

Is the yaw velocity, I _z is its inertia around the vertical axis through its center of gravity, L ₁ and L ₂ are the distances from the center of gravity to the front and rear axles, α is the average steering angle of the front axle, D ₁ and D ₂ indicates the drift stiffness of the front and rear axles, and δ indicates the drift angle.

、車両の長手方向速度Ｖのような、アンチロール制御法則で利用される複数の信号をさらに受け取る。 Control system, among other things, handle angle α, yaw speed

And further receiving a plurality of signals used in the anti-roll control law, such as the longitudinal velocity V of the vehicle.

The system is a minimum load to prevent lift from the road surface of the inner ring, the load is a normal stress F _z applied to the tire in order to take the inner ring of the subject, the stiffness to be added to the two axles of the vehicle A means 3 for calculating the maximum distribution is provided. Fz _ij is a normal stress applied to the wheel i of the axle j, and i and j are integers of 1 or 2.

For front axle wheels, the load is expressed as a function of lateral acceleration γ _T , longitudinal acceleration γ _L and vehicle weight:

ただし、ｋ_ａｖ＋ｋ_ａｒ＝１である。 The two rear axle wheels are as follows.

However, k _av + k _ar = 1.

  The method according to the invention determines the stiffness distribution between the front axle and the rear axle so that a minimum load is applied to one of the inner wheels during cornering, depending on the lateral and longitudinal acceleration of the vehicle.

If the maximum of the vehicle rear wheels are inner rings of cornering, the load _{F Zarint} must at minimum load _{F ZarintMin} above, therefore, the anti-roll stiffness distribution _{k ar} to the rear axle, which is defined as follows It must be less than or equal to the value k _arMax .

Lateral acceleration gamma _T, as shown in FIG. 2 showing the operation area of the vehicle which is defined by the stiffness distribution k _ar in the longitudinal direction acceleration gamma _L and rear axle, γ _{T =} 6m. s ⁻² and γ _L = 2 m. When s− ² and _kar is more than 0.6, it can be seen that the rear wheel, which is the inner ring during cornering, is lifted off the road surface.

In the case of a vehicle front wheel that is an inner wheel at the time of cornering, the load F _Zavint exceeds the minimum value F _ZavinMin , and the rigidity distribution to the front axle k _av is less than the maximum value k _avMax defined as follows. Must be.

FIG. 3 shows the vehicle operating region defined by the lateral acceleration γ _T , the longitudinal acceleration γ _L and the stiffness distribution k _av to the front axle. From this, the stiffness distribution k _arMax = 1−k _avMax to the rear axle is derived.

The method thus determines the maximum load distribution between the two front and rear axles, and at the same time, means 4 calculates the total anti-roll torque set point C _ARCons applied to the anti-roll system actuator. In the case of a two-axle anti-roll system, i.e. a system with actuators acting on two axles, the method is particularly suitable for driving situations defined by the vehicle lateral acceleration γ _T and speed V according to the anti-roll control law. Accordingly, the stiffness distribution set point k _{arCons to} be added between the two axles to obtain the desired static response of the vehicle is also calculated.

Thus, at the output of means 4, the method sends out the total anti-roll torque set point C _ARCons and the desired anti-roll load distribution set point k _arCons . In the means 5 for preventing the front or rear inner ring from rising, the method calculates the saturation torque distributed to the front or rear active anti-roll bar. This anti-roll torque saturation is necessary to allow the calculated torque value to actually be applied. In fact, since the torque is distributed from the active anti-roll bar, the suspension spring also contributes to the roll rigidity of the vehicle and its distribution. Extreme values close to the corresponding distribution cannot be reached when k = 0, i.e. the rear roll stiffness is zero, or k = 1, i.e. the front roll stiffness is zero, so the distribution is For example, it is necessary to saturate between 0.1 and 0.9.

The inner ring lifting prevention means 5 performs the following various functions shown in FIG. The function 6 for saturating the distribution of the anti-roll stiffness includes the maximum distribution k _arMax for preventing the rear inner ring from being lifted up calculated by the means 3 or k _avMax for preventing the front inner ring from being lifted _up, and the front calculated by the means 4 The rigidity distribution set point k _arCons between the rear axles is received by the input unit, and the output unit outputs a saturation value between the upper limit and the lower limit of the load distribution k _arSat . This distribution between the two axles of the vehicle is _equal to the saturation saturation distribution k _avSat to the front axle which gives the front torque set point C _ARV by the multiplication 10 multiplied by the anti-roll torque set point C _ARCons, and also anti-roll _{Multiplication} with the torque set point C _ARCons results in a saturation distribution k _arSat of stiffness to the rear axle that provides a torque set point C _ARR applied to the rear axle.

In the case of a single axle anti-roll system, the total torque applied by the actuator to the vehicle's active anti-roll single axle is calculated as shown in the block diagram of FIG. 5 and the stiffness distribution between the two axles is _Derived from torque set point C _ARCons .

  As with both axle anti-roll systems, the method calculates the saturation torque to send to the front or rear active anti-roll axle actuator for the same reason. The front inner ring or the rear inner ring anti-lifting means 5 performs the function shown in the diagram of FIG. 6 or 7 by the front single axle anti-roll or the rear single axle anti-roll.

When the rear single axle anti-roll is used to prevent the rear inner ring from lifting (FIG. 6), the wheel _lift prevention means 5 calculates the maximum distribution k _arMax for preventing the rear inner ring from rising from the calculation means 3 to the total anti- _roll. The roll torque set point C _ARCons is received from the means 4 at the input unit. The absolute value 7 of the desired total torque set point is combined with the value of the stiffness distribution set point _karCon between the front and rear axles, characteristic of the vehicle and determined by the mapping 8 during vehicle development. As the anti-roll torque increases at the front, the load distribution to the rear decreases.

The maximum distribution value k _arMax and the value of the set point k _arCons obtained by mapping are compared by the saturation function 6 of the distribution set point. If the distribution set point is less than the maximum distribution, the set point is taken into account in the calculation of the total torque set point applied to the rear axle. Conversely, when the set point _karCons is greater than the maximum distribution, the set point is replaced with the maximum distribution to obtain the total torque.

The calculation of the total torque sent to the rear axle actuator is obtained by inverting the previous load distribution versus torque curve 9 and then multiplying 10 by ± 1 depending on the sign of the total torque set point _CARCons .

In order to prevent the front wheel from lifting when the rear axle has an anti-roll system, the saturation function 6 takes into account the maximum value of the front stiffness k _avMax calculated by the means 3, and determines the value of the rear stiffness from there. _Derived (k _arMax = 1−k _avMax ) and compare it to the desired distribution set point obtained from the total torque set point C _ARCons .

  FIG. 7 corresponds to an anti-roll system for a vehicle front axle. In this case, the mapping 8 linking all torque set points to be applied with the rear load distribution set points exhibits the opposite characteristics of the rear single axle case.

In fact, an increase in torque applied to the front axle results in a decrease in load distribution to the rear axle. As with the previous allocation setpoint _{k Arcons} the desired stiffness derived from total torque set point _{C Arcons} is compared with the maximum allocation _{k ARMAX,} larger than that value, they are replaced by their value.

  Therefore, this control method can delay or prevent the inner ring from being lifted during cornering by acting on the active anti-roll system, and has the advantage of operating continuously. This method can be regarded as corresponding to saturation of the torque or stiffness distribution that varies depending on the driving situation according to the technology.

It is a block diagram of a control system of both axle anti-roll devices of a vehicle. A lateral acceleration gamma _T, the longitudinal acceleration gamma _L, the operation area of the vehicle which is defined by the stiffness distribution k _ar for the rear axle shown. A lateral acceleration gamma _T, the longitudinal acceleration gamma _L, the operation area of the vehicle which is defined by the stiffness distribution k _ar for front axle shown. It is a detailed block diagram of the lifting prevention means of the front or rear inner ring in the case of both axle anti-roll systems. It is a block diagram of the control system of a single axle anti-roll apparatus. It is a detailed block diagram of the front or rear inner ring lifting prevention means in the case of a front single axle anti-roll system. FIG. 6 is a detailed block diagram of the front or rear inner ring lifting prevention means in the case of a rear single axle anti-roll system.

Claims (10)

  In a control method for an active anti-roll system for a motor vehicle with an actuator that acts on the stiffness of the anti-roll bar at the level of the front and rear axles and in particular an actuator controlled by the ECU in accordance with the lateral acceleration of the vehicle, Determine the total anti-roll torque to be applied to the rear axle, and the total anti-roll torque is calculated between the two axles calculated so that one of the two inner rings during cornering has a minimum load to prevent its lifting A control method that is derived from a rigid distribution and corresponds to a desired set point that is determined according to the lateral acceleration, speed, and static gain of the vehicle during steering operation.   In order to prevent the front inner wheel or the rear inner wheel from being lifted by a curve, the maximum value of the rigidity distribution to the front axle or the rear axle that applies the minimum load to the front inner wheel or the rear inner wheel is set in the lateral and longitudinal directions of the vehicle. The control method according to claim 1, wherein calculation is performed according to acceleration.   In the case of both axle active anti-roll systems, the determined total anti-roll torque is the optimal stiffness distribution corresponding to one of the two front and rear inner wheels, depending on the vehicle's lateral acceleration, speed and static gain. According to the optimum stiffness distribution obtained by saturating the set point of the stiffness distribution determined by the maximum value of the stiffness distribution that prevents the wheel from lifting up, and is characterized by being distributed between the two front and rear axles. The control method according to claim 2.   In the case of a single axle active anti-roll system acting on the rear axle, the determined total anti-roll torque is the optimum rear stiffness distribution corresponding to one of the two front and rear inner wheels, the vehicle lateral acceleration, The distribution set point determined according to the speed and static gain is added to the rear axle according to the optimum rigidity distribution of the rear obtained by saturating the maximum value of the rigidity distribution that prevents the wheel from lifting. The control method according to claim 2.   In the case of a single axle active anti-roll system acting on the front axle, the determined total anti-roll torque is the optimal rear stiffness distribution corresponding to one of the two front and rear inner wheels to prevent the wheel from lifting up 3. The control method according to claim 2, wherein the control method is applied to the front axle in accordance with an optimum rear rigidity distribution obtained from a front distribution set point saturated with a maximum rigidity distribution value. In the control apparatus of the active anti-roll system for vehicles controlled by the method according to any one of claims 1 to 5, comprising an ECU that controls an actuator that acts on the rigidity of the anti-roll bar.
Means (3) for calculating the maximum distribution of rigidity applied to the two axles of the vehicle so that the inner ring receives a minimum load that prevents the inner ring from lifting from the road surface. _L ) and means (3) for receiving lateral acceleration (γ _T );
Means (4) for calculating a total anti-roll torque set point (C _ARCons ) applied to the actuator of the anti-roll system;
Means (5) for preventing the front inner ring or the rear inner ring from lifting, and means (5) for calculating a saturation torque distributed to the front or rear active anti-roll bar;
A control device comprising: The means (4) for calculating the total anti-roll torque set point (C _ARCons ) applied to the actuators of the anti-roll system also calculates the stiffness distribution set point (k _arCons ) applied to the front and rear axles of the vehicle. 7. A control device according to claim 6, for a dual axle active anti-roll system for a vehicle. The means (5) for preventing the inner ring from lifting,
According to the maximum distribution (k _avMax or k _arMax ) calculated in the means (3) for preventing the front or rear inner ring from lifting, the rigidity between the front and rear axles calculated in the means (4) is determined. a distributed set point _{(k Arcons)} function to saturate (6), function of sending a saturation value between the upper and lower limits of the load distribution _{(the k Arsat)} at the output section (6),
Multiplication for sending the torque set point (C _ARR ) by multiplying the saturation value (k _arSat ) of the stiffness distribution set point by the anti-roll torque set point (C _ARCons ) calculated by the means (4). In combination with multiplication that gives the front torque set point (C _ARV ) by multiplying the saturation distribution (k _avSat ) of the rigidity to the front axle by the anti-roll torque set point (C _ARCons ). The multiplied function (10),
7. The control device according to claim 6, for both axle active anti-roll systems for vehicles, characterized in that The inner ring which _{receives the} maximum distribution ( _karMax ) for preventing the rear inner ring from rising from the calculating means (3) and the total anti-roll torque set point ( _CARCons ) from the means (4) at the input unit. The means (5) for preventing lifting is
A function (7) for calculating an absolute value of the total torque set point (C _ARCons );
The absolute value of the total torque set point (C _ARCons ) and the absolute value of the stiffness distribution set point (k _arCons ) between the front and rear axles characteristic of the vehicle and determined by mapping during vehicle development A function (8) for
A function (6) for saturating the anti-roll stiffness distribution, comparing the maximum distribution value ( _karMax ) with the set point ( _karCons ) value obtained by mapping, wherein the distribution setpoint is greater than the maximum distribution Is also taken into account in the calculation of the total torque setpoint applied to the rear axle, and when the setpoint ( _karCons ) is greater than the maximum distribution, the setpoint is set at the maximum distribution. A function (6) to obtain the total torque by replacing,
The total torque sent to the rear axle actuator is calculated by reversing the load distribution versus torque curve (9) and then multiplying by ± 1 (10) according to the sign of the total torque set point (C _ARCons ). Function and
The control device according to claim 6 for a single axle active anti-roll system for a vehicle, characterized in that In order to prevent the front wheel from lifting when the rear axle has an anti-roll system, the saturation function takes into account the maximum value of the front stiffness (k _avMax ) calculated by the means (3) and from there _10. The value of stiffness of is derived (k _arMax = 1−k _avMax ) and compared to the desired distribution set point obtained from the total torque set point (C _ARCons ). The control device described.

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