Towing assist device for notifying driver of backup conditions

1. A towing assistance device comprising:

a processor configured to implement:

an acquirer that acquires a coupling angle between a towing vehicle and a towed vehicle;

a determiner that determines whether the towed vehicle is movable backward in a coupling posture with the coupling angle maintained, when the towing vehicle is moved backward at a current steering angle; and

a notifier that issues information on a steering angle at which the towed vehicle is movable backward in the coupling posture, among selectable steering angles of the towing vehicle,

wherein the determiner acquires a first turning center of the towing vehicle and a second turning center of the towed vehicle to determine whether the towed vehicle is movable backward in the coupling posture, from a positional relationship between the first turning center and the second turning center, the first turning center being defined by the steering angle of the towing vehicle and a wheelbase length of the towing vehicle, the second turning center being defined by the coupling angle and a wheelbase length of the towed vehicle.

2. The towing assistance device according to claim 1 , wherein

the acquirer acquires the coupling angle from image data of a region including at least a coupling part of the towing vehicle and the towed vehicle.

3. The towing assistance device according to claim 1 , wherein

the notifier issues information on a balancing steering angle and information on a non-balancing steering angle by changing a mode of a steering wheel of the towing vehicle, the balancing steering angle representing an angle at which the towed vehicle is movable backward in the coupling posture, the non-balancing steering angle representing an angle at which the towed vehicle is not movable backward in the coupling posture.

4. The towing assistance device according to claim 1 , wherein

the notifier issues information on a balancing steering angle and information on a non-balancing steering angle in different voice modes, the balancing steering angle representing an angle at which the towed vehicle is movable backward in the coupling posture, the non-balancing steering angle representing an angle at which the towed vehicle is not movable backward in the coupling posture.

5. The towing assistance device according to claim 1 , wherein the notifier:

displays an image representing at least the towed vehicle on a display device, and

displays an indicator on the image in a superimposed manner, the indicator being stationary in a given position with respect to the towing vehicle and serving as a comparative criterion for behavioral change of the towed vehicle moving backward.

6. The towing assistance device according to claim 1 , wherein

the notifier displays, on a display device, an actual image based on image data of a region including a coupling part of the towing vehicle and the towed vehicle, and an overhead image of the towing vehicle and the towed vehicle coupled at the coupling angle based on the image data.

7. The towing assistance device according to claim 1 , wherein

upon issuance of a notification request for information on a steering angle at which the towed vehicle is movable backward in the coupling posture and being unable to acquire the coupling angle between the towing vehicle and the towed vehicle, the notifier refrains from issuing the information.

8. The towing assistance device according to claim 1 , wherein

when, in moving backward, the towing vehicle cannot transition, with a steering in an allowable steering range, to a balancing steering angle at which the towing vehicle and the towed vehicle are movable backward in the coupling posture at the maintained coupling angle, the notifier issues the information in a mode different from a mode when the towing vehicle is movable to the balancing steering angle.

9. A towing assistance device comprising:

a processor configured to implement:

an acquirer that acquires a coupling angle between a towing vehicle and a towed vehicle;

a determiner that determines whether the towed vehicle is movable backward in a coupling posture with the coupling angle maintained, when the towing vehicle is moved backward at a current steering angle; and

a notifier that issues information on a steering angle at which the towed vehicle is movable backward in the coupling posture, among selectable steering angles of the towing vehicle 1 , wherein the notifier:

displays a predicted motion line on a display device, the predicted motion line being of the towing vehicle in the backward movement of the towing vehicle at the current steering angle, and

displays information on a balancing steering angle and information on a non-balancing steering angle with the predicted motion line in different display modes, the balancing steering angle representing an angle at which the towed vehicle is movable backward in the coupling posture, the non-balancing steering angle representing an angle at which the towed vehicle is not movable backward in the coupling posture.

10. A towing assistance device comprising:

a processor configured to implement:

an acquirer that acquires a coupling angle between a towing vehicle and a towed vehicle;

a determiner that determines whether the towed vehicle is movable backward in a coupling posture with the coupling angle maintained, when the towing vehicle is moved backward at a current steering angle; and

a notifier that issues information on a steering angle at which the towed vehicle is movable backward in the coupling posture, among selectable steering angles of the towing vehicle, wherein the notifier:

displays, on a display device, an image representing at least the towed vehicle, and

displays, together with the image, as a non-balancing steering angle at which the towed vehicle is not movable backward in the coupling posture, at least one of a turning direction of the towed vehicle moving backward and a magnitude of a difference from the balancing steering angle at which the towed vehicle is movable backward in the coupling posture.