Vehicle driving support device and vehicle driving support method

1. A vehicle driving support device, comprising:

a reclining angle adjustment unit capable of adjusting a reclining angle of a driver's seat; and

a reclining angle controller configured to change the reclining angle by controlling the reclining angle adjustment unit depending on a driving mode, the driving mode being switchable between an automatic driving mode in which the vehicle steers autonomously and a manual driving mode in which a driver manually steers the vehicle,

wherein the reclining angle controller is configured to change the reclining angle, when the driving mode is switched between the automatic driving mode and the manual driving mode, so that the reclining angle in the automatic driving mode is larger than the reclining angle in the manual driving mode.

2. The vehicle driving support device according to claim 1 , further comprising:

a body size estimation unit configured to estimate a driver's body size; and

a manual driving posture setting unit configured to set a posture in which a driver's pressing force against a steering wheel is equal to or larger than a certain value that enables stable steering that is determined by the driver's body size estimated by the body size estimation unit, as a driving posture in accordance with the manual driving mode,

wherein the reclining angle controller is configured to control the reclining angle adjustment unit so that the driving posture of the driver in the manual driving mode is the posture set by the manual driving posture setting unit.

3. The vehicle driving support device according to claim 2 , further comprising:

a physical feature estimation unit configured to estimate a personal physical feature of the driver; and

a manual driving posture correction unit configured to correct the driving posture in accordance with the manual driving mode set by the manual driving posture setting unit with the personal physical feature estimated by the physical feature estimation unit.

4. The vehicle driving support device according to claim 3 , wherein the physical feature estimation unit is configured to estimate a physical flexibility of the driver as the personal physical feature of the driver, based on an action of the driver when the driver gets in or out of a vehicle.

5. The vehicle driving support device according to claim 2 , further comprising a front-rear position adjustment unit capable of adjusting a seat bottom face of the driver's seat in a front-rear direction of the vehicle,

wherein the reclining angle controller is configured to control the front-rear position adjustment unit in addition to the reclining angle adjustment unit, and

wherein the reclining angle controller, when detecting switching from the automatic driving mode to the manual driving mode, is configured to control the front-rear position adjustment unit so that a position of the seat bottom face of the driver's seat in the front-rear direction of the vehicle becomes a position in which the driving posture of the driver becomes the posture set by the manual driving posture setting unit.

6. The vehicle driving support device according to claim 2 , further comprising a steering adjustment unit capable of adjusting a position of a steering wheel in a front-rear direction and a top-bottom direction of the vehicle,

wherein the reclining angle controller is configured to control the steering adjustment unit in addition to the reclining angle adjustment unit, and

wherein the reclining angle controller, when detecting switching from the manual driving mode to the automatic driving mode, is configured to control the steering adjustment unit so that the position of the steering wheel in the front-rear direction and the top-bottom direction of the vehicle becomes the position in which the driving posture of the driver is the posture set by the manual driving posture setting unit.

7. The vehicle driving support device according to claim 1 ,

wherein in the automatic driving mode, an automatic travel control makes the vehicle travel automatically independent of a steering operation of the driver with a steering element,

further comprising a reliability degree detection unit configured to detect a reliability degree of the automatic travel control, based upon at least one of a number of sensing objects in the automatic travel control, a number of sensors necessary for sensing in the automatic travel control, a complexity of a sensing object in the automatic travel control, and an operation amount in the automatic travel control,

wherein the reclining angle controller is configured to control the reclining angle adjustment unit so that as the reliability degree detected by the reliability degree detection unit is lower in the automatic travel control, a driving posture of the driver is closer to a driving posture in accordance with the automatic driving mode from a driving posture in accordance with the manual driving mode.

8. A vehicle driving support method, comprising:

switching between an automatic driving mode in which the vehicle steers autonomously and a manual driving mode in which a driver manually steers the vehicle; and

changing a reclining angle of the driver's seat, when the driving mode is switched between the automatic driving mode and the manual driving mode, so that the reclining angle of the driver's seat in the automatic driving mode is larger than the reclining angle of the driver's seat in a manual driving mode.