JP4899710B2 - Vehicles that harmonize emergency avoidance drivability and vehicle body vibration suppression - Google Patents

Description

  The present invention relates to achieving optimal harmony between emergency avoidance drivability and suppression of vehicle body vibration in a vehicle such as an automobile.

In a vehicle such as an automobile, a vehicle body vibration such as pitching or rolling may occur in the vehicle body by a vehicle operation input such as an accelerator operation, a brake operation, or a steering operation by a driver. To deal with vehicle body vibration caused by such vehicle operation input, and use a mechanical model for tire vibration and unsprung and unsprung vibrations in suspensions, accelerator and brake operations are optimally suppressed. Alternatively, an example of a method for correcting an input command corresponding to a steering operation is described in Patent Document 1 below.
JP2004-168148

  Various types of vibration models have been established for vehicle vibrations in vehicles such as automobiles in which the vehicle body is suspended on wheels with tires by suspensions in which springs and dampers are placed side by side. The vehicle has electronic control that incorporates a microcomputer. The accelerator operation, the brake operation, or the steering operation by the driver is once calculated and processed together with other various signals indicating the driving state of the vehicle in the electronic control unit, and the engine etc. based on the calculation result In the vehicle configured to control the driving means, the braking means by the brake, or the steering means, it certainly corresponds to the accelerator operation, the brake operation, or the steering operation as shown in the above example. By properly correcting the driving operation input command, the vibration of the vehicle body caused by those operations is suppressed. To be possible.

  By the way, vehicles such as automobiles are sometimes subjected to emergency avoidance operation for avoiding collision, avoiding rollover, or avoiding wheel removal by the driver himself or by computer control by an electronic control unit. In such an emergency avoidance operation, if an accelerator operation, a brake operation, or a steering operation for suppressing vehicle body vibration is controlled by an electronic control device, or a spring constant of a spring or a damper damping coefficient is changed in the suspension, the vehicle The emergency avoidance drivability may be impaired.

  An object of the present invention is to provide a vehicle in which emergency avoidance drivability of a vehicle and suppression of vehicle body vibration are harmonized by paying attention to the above circumstances.

  In order to solve the above-described problems, the present invention includes a vehicle body, a steering unit including a driving unit, a braking unit, and a steering unit, and an electronic control unit, and the electronic control unit responds to a driver's steering operation. The electronic control unit is configured to perform vehicle avoidance operation when the vehicle is operated in an emergency avoidance manner. The present invention proposes a vehicle characterized in that the vehicle body vibration suppression control is changed.

  The change in the vehicle body vibration suppression control when the vehicle is in an emergency avoidance operation may be to suppress the vehicle body vibration suppression control, and is not particularly limited to this. It may be suppression until the vehicle body vibration suppression control is canceled.

  Alternatively, the change in the vehicle body vibration suppression control when the vehicle is in an emergency avoidance operation may be suppression of braking force reduction for vehicle body vibration suppression.

  Alternatively, the change in the vehicle body vibration suppression control when the vehicle is in an emergency avoidance operation may be a reduction in driving force reduction for vehicle body vibration suppression.

  The change in the vehicle body vibration suppression control when the vehicle is in an emergency avoidance operation may be a change in the spring constant of the suspension spring for the vehicle body vibration suppression control, and is not particularly limited to this. The suppression of the change in the spring constant may be to lower the spring constant.

  Alternatively, the change in the vehicle body vibration suppression control when the vehicle is in an emergency avoidance operation may be a change in the damping coefficient of the suspension damper for the vehicle body vibration suppression control, and is not particularly limited thereto. The suppression of the change of the damper damping coefficient may be to lower the damper damping coefficient.

  In any of the above cases, the vibration targeted by the vehicle body vibration suppression control may be pitching or rolling of the vehicle body.

  As described above, the vehicle has a driving means including a driving means, a braking means and a steering means, and an electronic control device, and the electronic control device controls the steering means in accordance with a driver's steering operation. In a vehicle that performs response control and simultaneously performs vehicle body vibration suppression control that suppresses vibration of the vehicle body, the electronic control unit changes the vehicle body vibration suppression control when the vehicle is operated in an emergency avoidance operation. If the vehicle is in an emergency avoidance operation, that is, it is more meaningful that the emergency avoidance operation of the vehicle is more effective than the suppression of the vehicle body vibration. Therefore, emergency avoidance drivability of the vehicle can be ensured in preference to suppression of vehicle body vibration. This is realized by canceling part or all of the execution of the vehicle body vibration suppression control.

  When the braking force is reduced to suppress the vehicle vibration, and the change in the vehicle vibration suppression control when the vehicle is operated for emergency avoidance is the suppression of the braking force reduction for suppressing the vehicle vibration, the emergency avoidance of the vehicle When driving, the braking force is not reduced to suppress vehicle vibration, and when the vehicle's emergency avoidance operation is mainly performed by braking the vehicle, reliable vehicle braking is performed during the vehicle's emergency avoidance operation.

  In addition, when the driving force is reduced to suppress the vehicle body vibration and the change of the vehicle body vibration suppression control when the vehicle is operated in an emergency avoidance operation is the suppression of the driving force reduction to suppress the vehicle body vibration, When the emergency avoidance operation is mainly performed by driving the vehicle, the driving force is not reduced for suppressing the vehicle body vibration during the emergency avoidance operation of the vehicle, and the emergency avoidance operation of the vehicle is mainly performed by driving the vehicle. In addition, reliable vehicle driving is performed during emergency avoidance operation of the vehicle.

  In a vehicle in which the vehicle body is supported on wheels by a suspension provided with a spring or a damper, the vehicle body resonates depending on the value of the longitudinal acceleration or the lateral acceleration acting on the vehicle body during braking or acceleration, resulting in a large pitching. There is a risk of vehicle body vibration such as rolling. If vehicle body vibration suppression control changes the spring constant of the suspension or the damping coefficient of the damper to avoid such resonance, the vehicle body vibration during emergency avoidance operation where the vehicle is suddenly braked or accelerated to avoid obstacles. Changes in the suspension spring constant and damper damping coefficient for suppression control are not suitable, and there is a risk that vehicle body vibration will be amplified and the emergency avoidance drivability of the vehicle will be impaired. In particular, a decrease in vehicle emergency avoidance drivability due to the interference of the vehicle body vibration suppression control is likely to occur when a spring constant or a damper damping coefficient is reduced to suppress vehicle body vibration. On the other hand, when the vehicle is operated in an emergency avoidance manner, if the suspension spring constant and the damper damping coefficient for the vehicle body vibration suppression control are changed, particularly if the reduction thereof is suppressed, the above-described problem occurs. Is avoided.

  FIG. 1 is a block diagram showing a main part of a configuration according to the present invention of a vehicle according to the present invention. In the figure, reference numeral 10 denotes a vehicle body (VB), which is supported by a pair of front wheels 12 and a pair of rear wheels 14 via a front wheel suspension 16 and a rear wheel suspension 18 in which springs and dampers are juxtaposed. The springs and dampers of the suspensions 16 and 18 are configured as variable springs and variable dampers whose spring constants and damping coefficients are variably controlled. Reference numeral 20 denotes a braking / driving device including a driving device (DU) and a braking device (BU) (the driving function or the braking function depending on the case is referred to as braking / driving, hereinafter the same). Reference numeral 22 denotes an electronic control unit (ECU). The vehicle 10, the variable mechanism for the spring constants and damping coefficients of the suspensions 16 and 18, the drive unit (DU), the brake unit (BU), and the electronic control unit 22 are not specifically shown, but they are general. A vehicle body of a four-wheeled vehicle having a general structure, a driving device comprising a combination of an engine and a transmission having a general structure, a braking device having a hydraulic circuit operated by a solenoid valve, and a microcomputer known as an electronic control device for a vehicle An electronic control device may be provided, and the structure of these components itself is not related to the gist of the present invention, and thus a detailed description of the structure of these components is omitted to avoid redundancy of the specification.

  The accelerator opening, the master cylinder hydraulic pressure, and the steering angle, which are steering inputs by the driver, are provided as part of the functional configuration in the electronic control unit 22 together with the vehicle speed and gear ratio, which are parameters indicating the driving state of the vehicle. Based on the accelerator opening, the master cylinder hydraulic pressure, the steering angle, the vehicle speed, the gear ratio, or in addition to any other input parameters, The driving force or braking force (braking / braking force) requested by the driver is calculated. The braking / driving force calculation device 24 is provided with a command signal indicating the calculated driver-requested braking / driving as a part of the functional configuration in the electronic control device 22 as well, and is already known in various aspects. Transmission to a braking / driving device control device 26 having a control function that combines an electronic fuel injection control device (EFI) and an electronic transmission control device (ECT) with an electronic braking control device (ECB) for computer-controlled braking It is supposed to be. However, this braking / driving command signal was corrected in the middle of its transmission by selectively correcting a part of the signal by the vehicle body vibration suppression control device (VC) 28 provided by the present invention and described below. A driver-requested braking / driving force command signal is introduced into the braking / driving device controller 26. The vehicle body vibration suppression control device 28 may also be provided in the electronic control device 22 as part of a functional configuration.

  The braking / driving device control device 26 performs braking / driving such as vehicle speed, engine speed, and gear ratio based on the corrected driver-requested braking / driving force commanded from the braking / driving force calculation device 24 via the vehicle body vibration suppression control device 28. The throttle opening, the gear ratio, and the brake hydraulic pressure are determined while referring to the vehicle operation parameters that affect the control, and signals for instructing them are transmitted to the braking / driving device 20.

  The braking / driving device 20 operates in accordance with the commanded throttle opening of the engine portion, operates in accordance with the commanded gear ratio, and operates in the brake hydraulic pressure in which the brake portion is commanded, Drive or brake the front wheel 12 or the rear wheel 14 or both. Movements generated in the vehicle body 10 when the wheels are driven by a drive unit (DU) or braked by a brake unit (BU), particularly vibrations such as pitching vibration and rolling vibration, are caused by suspension stroke, pitch angle, and roll angle. It appears as a change.

  The value of the braking / driving force transmitted from the braking / driving device 20 to the wheels 12, 14 and the change in the suspension stroke, pitch angle, and roll angle caused by the vehicle body are introduced into the vehicle body vibration suppression control device 28.

  The vehicle body vibration suppression control device 28 incorporates a vehicle body vibration model (a so-called sprung vibration model), and predicts the vibration of the vehicle body in a feed-forward manner based on a frequency analysis of a driving force or a braking force applied to the vehicle body. The driver requested braking / driving force is corrected so as to suppress the vibration of the vehicle body, and either one or both of the spring constant and the damping coefficient of the selected one of the suspensions 16 and 18 are controlled, and the vibration suppression control result thereof The feedback correction of the driver demanded braking / driving force and one or both of the spring constant and the damping coefficient of the suspension are referred to.

Further, the braking / driving force calculation device 24 obtains the accelerator opening increase speed, the master cylinder oil pressure increasing speed, and the steering angular speed (absolute value) from the accelerator opening degree, the master cylinder oil pressure, and the time change rate of the steering angle. 2 based on the map shown in FIG. 2 as an example, it is determined whether or not the vehicle is in an emergency avoidance driving state, and when it is determined that the vehicle is in an emergency avoidance driving state, a command signal to that effect is sent to the vehicle body vibration suppression. This is sent to the control device 28 to change the vehicle body vibration suppression control by the vehicle body vibration suppression control device 28. The map of FIG. 2 is obtained by increasing one or two of the accelerator opening increase speed (Ra) , the master cylinder hydraulic pressure increase speed (Rm) , the steering angular speed (Rs) (absolute value), and the vehicle speed (V). When the relative relationship between the accelerator opening increase speed or the master cylinder hydraulic pressure increase speed and the steering angular speed (absolute value) or the vehicle speed enters the shaded area in the figure, it is determined that the vehicle is in the emergency avoidance driving state. is there.
The shaded portion in the figure shows the relation between the accelerator opening increase speed limit value (Rac) when the steering angular speed (Rs) is 0 in the judgment based on the combination of the accelerator opening increasing speed (Ra) and the steering angular speed (Rs). The ratio of the accelerator opening increase speed (Ra) and the ratio of the margin of the steering angular speed (Rsc-Rs) to the steering angular speed limit value with respect to the steering angular speed limit value (Rsc) when the accelerator opening increase speed (Ra) is 0 are equal. A region where at least one of the accelerator opening increasing speed (Ra) and the steering angular speed (Rs) increases beyond the state,
In the judgment based on the combination of the accelerator opening increasing speed (Ra) and the vehicle speed (V), the accelerator opening increasing speed (Ra) with respect to the accelerator opening increasing speed limit value (Rac) when the vehicle speed (V) is zero. The accelerator opening increase speed (Ra) exceeds the state in which the ratio of the vehicle speed margin value (Vc-V) to the vehicle speed limit value is equal to the vehicle speed limit value (Vs) at 0 and the accelerator opening increase speed (Ra). And at least one of the vehicle speed (V) is an increased area,
In the determination based on the combination of the master cylinder hydraulic pressure increase rate (Rm) and the steering angular velocity (Rs), the master cylinder hydraulic pressure increase rate (Rm) with respect to the master cylinder hydraulic pressure increase rate limit value (Rmc) when the steering angular velocity (Rs) is zero. ) And the ratio of the steering angular velocity margin value (Rsc-Rs) to the steering angular velocity limit value with respect to the steering angular velocity limit value (Rsc) when the master cylinder hydraulic pressure increase rate (Rm) is 0 An area in which at least one of the increasing speed (Rm) and the steering angular speed (Rs) is increased;
In the determination based on the combination of the master cylinder oil pressure increase speed (Rm) and the vehicle speed (V), the master cylinder oil pressure increase speed (Rm) with respect to the master cylinder oil pressure increase speed limit value (Rmc) when the vehicle speed (V) is zero. The master cylinder hydraulic pressure increase speed (Rm) exceeds the state where the ratio of the vehicle speed margin value (Vc-V) to the vehicle speed limit value is equal to the vehicle speed limit value (Vc) when the ratio is equal to the master cylinder hydraulic pressure increase speed (Rm). This is a region where at least one of the vehicle speed (V) is increased.

  The change of the vehicle body vibration suppression control when the vehicle enters the emergency avoidance driving state is to suppress the vehicle body vibration suppression control to an arbitrary degree until the vehicle is canceled as described above. In the process in which the vibration suppression control device 28 transmits the driver-requested braking / driving force calculated by the braking / driving force calculation device 24 to the braking / driving device control device 26, the vibration suppression control device 28 is changed (particularly reduced) to suppress vehicle body vibration. Alternatively, it is possible to suppress the change (particularly reduction) of the spring constant or damping coefficient by acting on the suspensions 16 and 18 to suppress the vehicle body vibration, and thereby the vehicle body vibration when the vehicle is in the emergency avoidance driving state. It is avoided that the suppression control interferes with this and the emergency avoidance drivability of the vehicle is impaired.

  While the present invention has been described in detail with respect to one embodiment thereof, it will be apparent to those skilled in the art that various modifications can be made within the scope of the present invention.

The block diagram which shows the principal part of the structure which concerns on this invention of the vehicle by this invention. The figure which shows an example of the map for judging that the vehicle is in the emergency avoidance driving state.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vehicle body, 12 ... Front wheel, 14 ... Rear wheel, 16, 18 ... Suspension, 20 ... Braking / driving device, 22 ... Electronic control device, 24 ... Braking / driving force calculating device, 26 ... Braking / driving device control device, 28 ... Vehicle body Vibration suppression control device

Claims (11)

A vehicle body, a steering means including a driving means, a braking means, and a steering means, and an electronic control device, and the electronic control device performs driving operation response control for controlling the steering means in accordance with a driver's steering operation. At the same time, in a vehicle that performs vehicle body vibration suppression control that suppresses the vibration of the vehicle body, the electronic control unit controls whether the vehicle has a combination of the accelerator opening increase speed and the steering angular speed, the accelerator opening increase speed, and the vehicle speed. The vehicle body vibration suppression control is changed when an emergency avoidance operation is performed based on at least one combination selected from a combination, a combination of a master cylinder hydraulic pressure increase speed and a steering angular speed, and a combination of a master cylinder hydraulic pressure increase speed and a vehicle speed. We have been,
In the determination based on the combination of the accelerator opening increase speed and the steering angular speed, the ratio of the accelerator opening increasing speed to the accelerator opening increasing speed limit value at the steering angular speed 0 and the steering angular speed limit at the accelerator opening increasing speed 0 When the ratio of the margin value of the steering angular speed up to the steering angular speed limit value with respect to the value exceeds an equal state and at least one of the accelerator opening increasing speed and the steering angular speed increases, the emergency avoidance operation is performed.
In the judgment based on the combination of the accelerator opening increase speed and the vehicle speed, the ratio of the accelerator opening increasing speed to the accelerator opening increasing speed limit value at the time of the vehicle speed 0 and the vehicle speed with respect to the vehicle speed limit value at the time of the accelerator opening increasing speed 0:00. Suppose that emergency avoidance operation was performed when at least one of the accelerator opening increase speed and the vehicle speed increased beyond the state where the ratio of the margin value of the vehicle speed to the limit value was equal,
In the determination based on the combination of the master cylinder hydraulic pressure increase speed and the steering angular speed, the ratio of the master cylinder hydraulic pressure increase speed to the master cylinder hydraulic pressure increase speed limit value at the zero steering angular speed and the steering angular speed limit at the zero master cylinder hydraulic pressure increase speed. When the ratio of the margin value of the steering angular speed to the steering angular speed limit value with respect to the value exceeds an equal state and at least one of the master cylinder hydraulic pressure increase speed and the steering angular speed increases, the emergency avoidance operation is performed.
In the determination based on the combination of the master cylinder oil pressure increase speed and the vehicle speed, the ratio of the master cylinder oil pressure increase speed to the master cylinder oil pressure increase speed limit value at the vehicle speed 0 and the vehicle speed relative to the vehicle speed limit value at the master cylinder oil pressure increase speed 0 A vehicle characterized in that an emergency avoidance operation is performed when at least one of a master cylinder hydraulic pressure increase speed and a vehicle speed exceeds a state where a ratio of margin values of vehicle speeds to a limit value is equal .   The vehicle according to claim 1, wherein the change of the vehicle body vibration suppression control when the vehicle is in an emergency avoidance operation is to suppress the vehicle body vibration suppression control.   The vehicle according to claim 2, wherein the suppression of the vehicle body vibration suppression control is a suppression until the vehicle body vibration suppression control is canceled.   The vehicle according to any one of claims 1 to 3, wherein the change of the vehicle body vibration suppression control when the vehicle is operated in an emergency avoidance operation is a suppression of a braking force reduction for suppressing the vehicle body vibration.   The vehicle according to any one of claims 1 to 3, wherein the change of the vehicle body vibration suppression control when the vehicle is operated in an emergency avoidance operation is suppression of driving force reduction for suppressing vehicle body vibration.   4. The change of the vehicle body vibration suppression control when the vehicle is in an emergency avoidance operation is a change of a spring constant of a suspension spring for the vehicle body vibration suppression control. The listed vehicle.   The vehicle according to claim 6, wherein the suppression of the change in the spring constant is suppression of a decrease in the spring constant.   The change in the vehicle body vibration suppression control when the vehicle is in an emergency avoidance operation is a change in the damping coefficient of the suspension damper for the vehicle body vibration suppression control. The listed vehicle.   9. The vehicle according to claim 8, wherein the suppression of the change of the damper damping coefficient is a suppression of lowering the damper damping coefficient.   The vehicle according to claim 1, wherein the vibration targeted by the vehicle body vibration suppression control is pitching of the vehicle body.   The vehicle according to claim 1, wherein the vibration targeted by the vehicle body vibration suppression control is rolling of the vehicle body.

Images