Vehicle coupling assistance device, vehicle coupling assistance method, vehicle coupling assistance system, and steering control device

A vehicle coupling assistance method for assisting in coupling between a vehicle and a trailer, the vehicle including a front-wheel steering device configured to control a steering angle of front wheels of the vehicle, a rear-wheel steering device configured to control a steering angle of rear wheels of the vehicle, and a first coupling part, the trailer including a second coupling part to be coupled to the first coupling part,

• the vehicle coupling assistance method comprising:
• acquiring a physical quantity relating to an angle of the second coupling part with respect to the first coupling part based on external world information acquired by an external world recognition unit;
• selecting, as a steering angle control mode, any one of a first steering angle control mode in which the steering angle of the front wheels and the steering angle of the rear wheels are controlled to achieve the same steering angle and a second steering angle control mode in which the steering angle of the front wheels and the steering angle of the rear wheels are controlled to achieve different steering angles in accordance with the physical quantity relating to the angle, such that:
• i) the first steering angle control mode is selected when a position of the second coupling part is within a range in which the coupling to the first coupling part through a parallel movement of the front wheels and the rear wheels is achieved, and ii) the second steering angle control mode is selected when the position of the second coupling part is not within the range in which the coupling to the first coupling part through a parallel movement of the front wheels and the rear wheels is achieved;
• and
• outputting steering angle control commands for executing control in the selected steering angle control mode to the front-wheel steering device and the rear-wheel steering device.

A vehicle coupling assistance system for assisting in coupling between a first coupling part included in a vehicle and a second coupling part included in a trailer,

• the vehicle coupling assistance system comprising:
• an external world recognition unit configured to acquire external world information on the vehicle;
• and
• a steering control unit configured to:
• acquire a physical quantity relating to an angle of the second coupling part with respect to the first coupling part based on the external world information acquired by the external world recognition unit;
• select, as a steering angle control mode, any one of a first steering angle control mode in which a steering angle of front wheels and a steering angle of rear wheels are controlled to achieve the same steering angle and a second steering angle control mode in which the steering angle of the front wheels and the steering angle of the rear wheels are controlled to achieve different steering angles in accordance with the physical quantity relating to the angle, such that:
• i) the first steering angle control mode is selected when a position of the second coupling part is within a range in which the coupling to the first coupling part through a parallel movement of the front wheels and the rear wheels is achieved, and ii) the second steering angle control mode is selected when the position of the second coupling part is not within the range in which the coupling to the first coupling part through a parallel movement of the front wheels and the rear wheels is achieved;
• and
• output steering angle control commands for executing control in the selected steering angle control mode;
• a front-wheel steering device configured to acquire the steering angle control command output from the steering control unit;
• and
• a rear-wheel steering device configured to acquire the steering angle control command output from the steering control unit.