CURVING TENDENCY DETECTION DEVICE IN VEHICLE, AND VEHICLE RESPONSE CONTROL APPARATUS USING SAME

Abstract

A curving tendency detection device is provided to detecting a curving tendency (curving frequency and amount of curvature) in a vehicle roadway or a vehicle running state (behavior). Basically, the curving tendency detection device has a lateral acceleration differential value calculation section and a curving tendency estimation section. The lateral acceleration differential value calculation section calculates vehicle lateral acceleration differential values of a vehicle lateral acceleration acting on a vehicle as the vehicle lateral acceleration varies over time. The curving tendency estimation section estimates the curving tendency based on the vehicle lateral acceleration differential value calculated by the lateral acceleration differential value calculation section. Thus, the curving can be reliably detected by effectively avoiding a false curving tendency in cases in which the left and right wheels have different effective diameters, or the vehicle is driving straight along a laterally tilted road.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of this original disclosure:

FIG. 1 is a schematic block diagram of a vehicle driving style determination apparatus equipped with a road curving tendency detection device in accordance with to one embodiment of the present invention;

FIG. 2 is a block diagram showing a gearshift control apparatus for a continuously variable transmission that uses the determination results obtained by the driving style determination apparatus shown in FIG. 1;

FIG. 3 is a schematic block diagram showing the details of the acceleration/deceleration tendency detection unit in FIG. 1;

FIG. 4 is a schematic block diagram showing the details of the curving tendency detection unit in FIG. 1;

FIG. 5 is a diagram describing the principle used to determine the formula for calculating the lateral acceleration of the vehicle;

FIG. 6 is a line characteristics diagram showing the filter gain characteristics of the low-pass filter constituting the curving tendency calculation unit in FIG. 4;

FIG. 7 is a pair of line characteristics diagrams showing the filter characteristics when the filter coefficient of the low-pass filter constituting the curving tendency calculation unit in FIG. 4 differs according to vehicle speed, with diagram (a) showing when the vehicle speed is 40 km/h, and diagram (b) showing the filter characteristics when the vehicle speed is 80 km/h;

FIG. 8 is a line filter characteristics diagram showing another example of a low-pass filter constituting the curving tendency calculation unit in FIG. 4;

FIG. 9 is a line filter characteristics diagram showing yet another example of a low-pass filter constituting the curving tendency calculation unit in FIG. 4;

FIG. 10 is a pair of action time charts of the curving tendency detection unit in FIG. 4, with diagram (a) showing an action time chart of a case in which the Butterworth filter is not used, and diagram (b) showing an action time chart of a case in which the Butterworth filter is used;

FIG. 11 is a schematic block diagram showing another example of the curving tendency detection unit in FIG. 1;

FIG. 12 is a pair of line characteristics diagrams showing the effects of correcting lateral acceleration with the corrective gain set by the lateral acceleration corrective gain setting unit in FIG. 11, with diagram (a) showing the level of lateral acceleration differential values determined based on uncorrected lateral accelerations, and diagram (b) showing the level of lateral acceleration differential values determined based on corrected lateral accelerations;

FIG. 13 is an action time chart for the curving tendency detection units shown in FIGS. 4 and 11 when the vehicle is traveling over a straight road;

FIG. 14 is an action time chart for the curving tendency detection units shown in FIGS. 4 and 11 when the vehicle is traveling over a curving road;

FIG. 15 is an action time chart for the curving tendency detection units shown in FIGS. 4 and 11 when a vehicle whose left and right tires have different effective diameters is traveling over a straight road;

FIG. 16 is an action time chart for the curving tendency detection units shown in FIGS. 4 and 11 when a vehicle whose left and right tires have different effective diameters is traveling over a curving road;

FIG. 17 is an action time chart obtained from the driving style determination apparatus shown in FIG. 1;

FIG. 18 is a flowchart showing the process of a driving style determination program executed by a microcomputer of the driving style determination apparatus shown in FIG. 1;

FIG. 19 is a flowchart showing the process of a driving style determination program executed by the microcomputer of the curving tendency detection unit in the driving style determination apparatus shown in FIG. 1 is switched to the unit in FIG. 11, and the driving style determination apparatus;

FIG. 20 is a functional block diagram showing a case in which the driving style determination apparatus shown in FIG. 1 is used to control the damping force of a shock absorber;

FIG. 21 is a functional block diagram showing a case in which the driving style determination apparatus shown in FIG. 1 is used to control the rigidity of a stabilizer;

FIG. 22 is a functional block diagram showing a case in which the driving style determination apparatus shown in FIG. 1 is used to control the assist force in power steering;

FIG. 23 is a schematic block diagram showing a vehicle driving style determination apparatus comprising a vehicle roadway curving tendency detection unit;

FIG. 24 is a schematic block diagram showing the details of the running state/curving tendency detection unit in FIG. 23; and

FIG. 25 is an action time chart for the running state/curving tendency detection unit shown in FIG. 24 when the vehicle is traveling over a curving road.

Claims

1. A curving tendency detection device comprising: a lateral acceleration differential value calculation section configured to calculate a lateral acceleration differential value of a lateral acceleration acting on a vehicle as the lateral acceleration varies over time; anda curving tendency estimation section configured to estimate a curving tendency of at least one of a vehicle roadway and a running state of the vehicle, with the curving tendency being estimated based on the lateral acceleration differential value calculated by the lateral acceleration differential value calculation section.

2. The curving tendency detection device according to claim 1, wherein the curving tendency estimation section is configured to estimate the curving tendency in the vehicle roadway.

3. The curving tendency detection device according to claim 2, wherein the curving tendency estimation section is further configured to estimate the curving tendency in the vehicle roadway based on a mean value of a plurality of the lateral acceleration differential values.

4. The curving tendency detection device according to claim 2, wherein the curving tendency estimation section comprises a filtering section configured to extract the vehicle acceleration differential value from an effective frequency range that corresponds to a detected running state of the vehicle, and to estimate the curving tendency in the vehicle roadway based on the mean output level of the vehicle lateral acceleration differential value that has passed through the filtering section.

5. The curving tendency detection device according to claim 4, wherein the filtering section includes a time delay element.

6. The curving tendency detection device according to claim 5, wherein the filtering section is further configured to use the effective frequency range that moves to a higher frequency range as vehicle speeds increase.

7. The curving tendency detection device according to claim 2, wherein the lateral acceleration differential value calculation section is further configured to reduce a peak of the lateral acceleration differential value with a reduction in vehicle speed.

8. The curving tendency detection device according to claim 1, wherein the curving tendency estimation section is configured to estimate the running state of the vehicle.

9. The curving tendency detection device according to claim 8, wherein the curving tendency estimation section is further configured to estimate the curving tendency based on a mean value of a plurality of the lateral acceleration differential values.

10. The curving tendency detection device according to claim 8, wherein the curving tendency estimation section comprises a filtering section configured to extract the vehicle acceleration differential value from an effective frequency range that corresponds to a detected running state of the vehicle, and to estimate the curving tendency based on the mean output level of the vehicle lateral acceleration differential value that has passed through the filtering section.

11. The curving tendency detection device according to claim 10, wherein the filtering section includes a time delay element.

12. The curving tendency detection device according to claim 11, wherein the filtering section is further configured to use the effective frequency range that moves to a higher frequency range as vehicle speeds increase.

13. The curving tendency detection device according to claim 8, wherein the lateral acceleration differential value calculation section is further configured to reduce a peak of the lateral acceleration differential value with a reduction in vehicle speed.

12. A vehicle response control apparatus comprising the curving tendency detection device according to claim 1, wherein the vehicle response control apparatus includes a controller configured to control a vehicle state so that an action response of the vehicle in relation to driving operations of a driver increases with an increase in the curving tendency as detected by the curving tendency detection device.

13. The vehicle response control apparatus according to claim 12, wherein the controller adjusts a damping force adjustment orifice of a shock absorber of the the vehicle.

14. The vehicle response control apparatus according to claim 12, wherein the controller adjusts a stabilizer rigidity switching mechanism of the vehicle.

15. The vehicle response control apparatus according to claim 12, wherein the controller adjusts a power steer assist mechanism of the vehicle.

16. A curving tendency detection device comprising: lateral acceleration differential value calculating means for calculating a lateral acceleration differential value of a lateral acceleration acting on a vehicle as the lateral acceleration varies over time; andcurving tendency estimating means for estimating a curving tendency of at least one of a vehicle roadway and a running state of the vehicle, with the curving tendency being estimated based on the lateral acceleration differential value calculated by the lateral acceleration differential value calculating means.

17. A curving tendency detection method comprising: calculating a lateral acceleration differential value of a lateral acceleration acting on a vehicle as the lateral acceleration varies over time; andestimating a curving tendency of at least one of a vehicle roadway and a running state of the vehicle, with the curving tendency being estimated based on the lateral acceleration differential value calculated by the lateral acceleration differential value calculating means.