TRAVEL ROUTE ESTIMATION DEVICE AND TRAVEL ROUTE ESTIMATION METHOD USED IN THE SAME DEVICE

• US 20110264302A1
• Filed: 12/26/2008
• Published: 10/27/2011
• Est. Priority Date: 12/26/2008
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Tsunekawa, Jun
• Granted Patent: US 8,989,913 B2
• Time in Patent Office: Days
• US Class Current: 701/1
• CPC Class Codes: B60W 2050/0051 combined with averaging
• CPC Class Codes: B60W 2050/0052 Filtering, filters
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 30/0953 the prediction being responsive to vehicle dynamic parameters
• CPC Class Codes: B60W 40/072 Curvature of the road
• CPC Class Codes: B60W 40/076 Slope angle of the road

Abstract

Provided is a travel route estimation device capable of accurately estimating, without excessively increasing communication load of the device, a shape of a travel route even when one'"'"'s own-vehicle is traveling on a travel route that does not have any objects installed on the route. A calculation section calculates and successively stores a radius of curvature of the travel route based on a yaw rate detected by a yaw rate detection section and on a traveling velocity detected by a velocity detection section. When conducting a filtering process for reducing variation of the calculate radius of curvature, the calculation section selects a filtering constant for multiplying the stored radius of curvature in accordance with the type of the travel route of the own-vehicle, and generates information representing a radius of curvature obtained by conducting at least one filtering process by using the selected filtering constant.

Claims

1. A travel route estimation device comprising:

a displacement velocity detection unit which detects a displacement velocity of one'"'"'s own-vehicle over a travel route surface;

a radius-of-curvature estimation unit which estimates, based on the displacement velocity, a radius of curvature of a travel route of the own-vehicle;

a filtering process unit which conducts a filtering process on the radius of curvature by using mutually different characteristics to respectively obtain a first radius of curvature and a second radius of curvature;

a weighted average unit which calculates a third radius of curvature obtained by multiplying weight constants respectively to the first radius of curvature and to the second radius of curvature, and by adding products of those;

a weight constant control unit which gradually changes, when a type of the travel route of the own-vehicle changes, the weight constants multiplied respectively to the first radius of curvature and to the second radius of curvature; and

a generation unit which generates information representing the third radius of curvature calculated by the weighted average unit.

2. The travel route estimation device according to claim 1, wherein the filtering process unit includes:

a first filtering process unit which calculates the first radius of curvature, by multiplying a relatively large filtering constant to the radius of curvature having a relatively short time period since being estimated and multiplying a relatively small filtering constant to the radius of curvature having a relatively long time period since being estimated, and by adding the radius of curvatures multiplied to the respective filtering constants; and

a second filtering process unit which calculates the second radius of curvature, by multiplying a relatively large filtering constant to the radius of curvature having a relatively long time period since being estimated and multiplying a relatively small filtering constant to the radius of curvature having a relatively short time period since being estimated, and by adding the radius of curvatures multiplied to the respective filtering constants;

wherein the weighted average unit calculates the third radius of curvature by multiplying the weight constants respectively to the first radius of curvature obtained from the filtering process by the first filtering process unit and to the second radius of curvature obtained from the filtering process by the second filtering process unit, and by adding products of those.

3. The travel route estimation device according to claim 2, wherein the weight constant control unit includes:

a first determination unit which determines whether or not the type of the travel route of the own-vehicle has changed from a straight route to a curve;

a second determination unit which determines whether or not the type of the travel route of the own-vehicle has changed from a curve to a straight route; and

a change unit which gradually changes the weight constants multiplied respectively to the first radius of curvature and the second radius of curvature when the type of the travel route of the own-vehicle is determined to have changed by the first determination unit and the second determination unit.

4. The travel route estimation device according to claim 3, wherein

the weight constant control unit further includes a calculation unit which calculates an absolute value of a difference obtained by subtracting, from a rotational angular velocity above a travel route surface of the own-vehicle estimated based on the first radius of curvature, a rotational angular velocity above a travel route surface of the own-vehicle estimated based on the second radius of curvature;

the first determination unit determines that the type of the travel route of the own-vehicle has changed from a straight route to a curve, if the first radius of curvature is less than a predetermined threshold and the absolute value is larger than a predetermined threshold; and

the second determination unit determines that the type of the travel route of the own-vehicle has changed from a curve to a straight route, if the second radius of curvature is less than a predetermined threshold and the absolute value is larger than a predetermined threshold.

5. The travel route estimation device according to claim 4, wherein the change unit gradual increases, relatively, a weight constant multiplied to the first radius of curvature if the first determination unit determines that the type of the travel route of the own-vehicle has changed, and gradual increases, relatively, a weight constant multiplied to the second radius of curvature if the second determination unit determines that the type of the travel route of the own-vehicle has changed.

6. The travel route estimation device according to claim 1, wherein the displacement velocity detection unit detects, as the displacement velocity, both a traveling velocity of the own-vehicle and a rotational angular velocity of the own-vehicle over the travel route surface.

7. The travel route estimation device according to claim 1, wherein the generation unit generates the information for a device that determines, by using the third radius of curvature as a prediction result of a traveling direction of the own-vehicle, whether or not the own-vehicle and another vehicle will collide.

8. A travel route estimation method comprising:

a displacement velocity detection step of detecting a displacement velocity of one'"'"'s own-vehicle over a travel route surface;

a radius-of-curvature estimation step of estimating, based on the displacement velocity, a radius of curvature of a travel route of the own-vehicle;

a filtering process step of conducting a filtering process on the radius of curvature by using mutually different characteristics to respectively obtain a first radius of curvature and a second radius of curvature;

a weighted average step of calculating a third radius of curvature obtained by multiplying weight constants respectively to the first radius of curvature and to the second radius of curvature, and by adding products of those;

a weight constant control step of gradually changing, when a type of the travel route of the own-vehicle changes, the weight constants multiplied respectively to the first radius of curvature and to the second radius of curvature; and

a generation step of generating information representing the third radius of curvature calculated at the weighted average step.

9. (canceled)