Headlight optical-axis control device

A headlight optical-axis control device comprising a controller to calculate a vehicle angle indicating a tilt angle of a vehicle relative to a road surface, using accelerations in perpendicular and longitudinal directions which are detected by an acceleration sensor mounted on the vehicle, and to generate a signal for adjusting an optical axis of a headlight,

• the controller having information that is set in advance and indicates reference accelerations in the perpendicular and longitudinal directions, and
• the controller being configured to:
• calculate vehicle angles based on ratios, each ratio being a ratio of a difference between the reference acceleration in the longitudinal direction and the acceleration in the longitudinal direction detected during traveling of the vehicle, to a difference between the reference acceleration in the perpendicular direction and the acceleration in the perpendicular direction detected during traveling of the vehicle by the acceleration sensor;
• calculate a plot of the calculated vehicle angles in a coordinate system that is set to have a first axis representing a difference between the reference acceleration and the acceleration in the longitudinal direction and a second axis representing a vehicle angle, thereby to derive a vehicle angle corresponding to a case where a change of the acceleration in the longitudinal direction is zero;
• and
• generate a signal for controlling the optical axis of the headlight on a basis of the derived vehicle angle.