Parking assistance device

1. A parking assist device that calculates a parking path from a current position of an own vehicle to a target parking position, the parking assist device comprising:

a sensor;

an input; and

a processor that is communicatively coupled to the sensor and the input, wherein the processor is configured to:

determine, using the sensor, the current position of the own vehicle;

receive, using the input, the target parking position;

calculate a backward-direction path for taking the own vehicle out from the target parking position based on constraint conditions of a parking space and an own-vehicle behavior and a number of turns of the own vehicle;

set a plurality of connection candidate positions on the backward-direction path;

sequentially calculate paths respectively leading to the plurality of connection candidate positions from the current position of the own vehicle based on the number of turns of the own vehicle and the current position of the own vehicle;

select a connection candidate position to which a path having a shortest moving distance from the current position of the own vehicle leads;

determine whether the own vehicle collides with an obstacle;

change a gear of the own vehicle to change a moving direction of the own vehicle between a forward direction of the own vehicle and a backward direction;

determine the path leading to the selected connection candidate position as a forward-direction path; and

set the parking path by combining the backward-direction path and the forward-direction path such that a steering direction of the own vehicle is changed.

2. The parking assist device according to claim 1 , wherein the processor is further configured to:

determine whether the own vehicle can reach each of the connection candidate positions from the current position of the own vehicle by one-side steering or by S-shaped steering; and

select the connection candidate position by determining that the own vehicle can reach the connection candidate position from the current position of the own vehicle by one-side steering or by S-shaped steering.

3. The parking assist device according to claim 1 , wherein the processor is further configured to:

calculate, in a case of backward parallel parking, the forward path for the own vehicle to reach a reachable limit position with respect to a front obstacle by steering to either the left or the right and moving forward, and a backward path for the own vehicle to reach a reachable limit position with respect to a rear obstacle by straightening the front wheels with respect to the own vehicle and moving backward.

4. The parking assist device according to claim 1 , wherein the processor is further configured to:

calculate, in a case of forward parallel parking, a backward path for the own vehicle to reach a reachable limit position with respect to a rear obstacle by steering to either the left or the right and moving backward, and a forward path for the own vehicle to reach a reachable limit position with respect to a front obstacle by straightening the front wheels with respect to the own vehicle and moving forward.

5. The parking assist device according to claim 1 , wherein the processor is further configured to:

determine whether the own vehicle can reach each of the connection candidate positions from the current position of the own vehicle by one-side steering;

select the connection candidate position by determining that the own vehicle can reach the connection candidate position from the current position of the own vehicle by one-side steering; and

select the connection candidate position when an axis line of the own vehicle at the current position of the own vehicle and the axis line of the own vehicle at a reaching position after taking out from the target parking position cross, a turning circle at the current position and the axis line at the reaching position do not cross, and the axis line at the current position and a turning circle at the reaching position do not cross, the axis line of the own vehicle passing at an center of the own vehicle and extending in a longitudinal direction of the own vehicle.