Host-vehicle risk acquisition device and method

1. A host-vehicle risk acquisition device comprising:

a host-vehicle sensor that detects a travel state of a host vehicle;

a host-vehicle path acquisition portion that acquires a path of a host-vehicle;

an obstacle path acquisition portion that acquires a plurality of paths of an obstacle existing around the host-vehicle;

a collision risk acquisition portion that acquires an actual collision risk, which is a collision risk between the host-vehicle and the obstacle when the host-vehicle is in a travel state detected by the host-vehicle sensor based on the path of the host-vehicle and the plurality of paths of the obstacle; and

an offset risk acquisition portion that acquires an offset risk, which is a collision risk between the host-vehicle and the obstacle in an offset travel state, which is obtained by changing the travel state of the host-vehicle detected by the host-vehicle sensor by adding an offset value to the current travel state.

2. The host-vehicle risk acquisition device according to claim 1 , wherein the travel state of the host-vehicle includes at least one of a position and a speed of the host-vehicle.

3. The host-vehicle risk acquisition device according to claim 1 , further comprising:

an offset risk storing portion that stores the offset risk acquired by the offset risk acquisition portion; and

a travel state evaluation portion that compares the offset risk stored in the offset risk storing portion with the actual collision risk obtained by the collision risk acquisition portion to evaluate the travel state of the host-vehicle.

4. The host-vehicle risk acquisition device according to claim 3 , wherein the travel state evaluation portion calculates a time variation in a difference between the offset risk stored in the offset risk storing portion and the actual collision risk obtained by the collision risk acquisition portion, and evaluates the travel state of the host-vehicle based on the calculated time variation in the difference between the offset risk and the actual collision risk.

5. The host-vehicle risk acquisition device according to claim 4 , wherein the travel state evaluation portion evaluates the travel state of the host-vehicle using a mean value and a variance of the time variation in the difference between the offset risk and the actual collision risk.

6. The host-vehicle risk acquisition device according to claim 1 , wherein the offset risk acquisition portion acquires a plurality of offset risks respectively calculated for a plurality of offset travel states of the host-vehicle, which are offset from the travel state of the host-vehicle by the amounts different from each other.

7. The host-vehicle acquisition device according to claim 6 , wherein the offset risk acquisition portion determines a most preferable travel state from the plurality of offset travel states based on the plurality of offset risks acquired by the offset risk acquisition portion,

the host-vehicle risk acquisition device further comprising a display that displays the most preferable travel state.

8. The host-vehicle risk acquisition device according to claim 1 , further comprising:

an offset portion that calculates the offset travel state which is offset from the travel state,

wherein the host-vehicle path acquisition portion acquires a first path that is predicted to be taken by the host-vehicle in the travel state, and a second path that is predicted to be taken by the host-vehicle in the offset travel state,

wherein the collision risk acquisition portion acquires the actual collision risk based on the first path and the plurality of paths of the obstacle, and

wherein the offset risk acquisition portion acquires the offset risk based on the second path and the plurality of paths of the obstacle.