Automatic leveling apparatus and method of headlamp for vehicle

An automatic leveling apparatus of a headlamp for a vehicle for detecting a change in an attitude of a vehicle and adjusting an optical axis of the headlamp to cancel the change in the attitude of the vehicle, said automatic leveling apparatus comprising:

• an actuator for inclining the optical axis of the headlamp in an up and down direction relative to a vehicle body;
• a vehicle height detector for detecting a displacement amount x of a suspension on a side of a front wheel or a rear wheel in the vehicle;
• a control section for calculating a change amount dHr of the vehicle height from an equation dHr=Cx+D based on the displacement amount x of the suspension and control constants inherent to the vehicle (C, D), and for calculating a pitch angle P which indicates the change in the attitude of the vehicle from an equation P=E·dHr+F based on the change amount dHr of the vehicle height and control constants inherent to the vehicle (E, F) and for controlling the actuator based on the pitch angle;
• a control constant recording section for replacing the initial value of delivery test data with the control constants inherent to the vehicle (C, D, E, F) which are written after attaching the headlamp to the vehicle and for recording them;
• a control constant determining section for determining whether the control constants inherent to the vehicle (C, D, E, F) are recorded to the control constant recording section;
• and
• a control stop section for stopping the control to the actuator when the control constants inherent to the vehicle (C, D, E, F) are not correctly recorded to the control constant recording section.

An automatic leveling apparatus of a headlamp for a vehicle for detecting a change in an attitude of a vehicle and adjusting an optical axis of the headlamp to cancel the change in the attitude of the vehicle, said automatic leveling apparatus comprising:

• an actuator for inclining the optical axis of the headlamp in an up and down direction relative to a vehicle body;
• a front-side vehicle height sensor and a rear-side vehicle height detector for detecting a displacement amount x of a suspension on a side of a front wheel or a rear wheel in the vehicle;
• a control section for calculating a change amount dHf of the vehicle height on the front wheel side from an equation dHf=Ax+B based on the displacement amount x of the front-wheel-side suspension and control constants inherent to the vehicle (A, B), for calculating a change amount dHr of the vehicle height on the rear wheel side from an equation dHr=Cx+D based on the displacement amount x of the rear-wheel-side suspension and control constants inherent to the vehicle (C, D), and for calculating a pitch angle P which indicates the change in the attitude of the vehicle from an equation P=arctan[(dHf-dHr)/W] based on the change amounts dHf and dHr of the vehicle height and a wheel base W as a control constant inherent to the vehicle, and for controlling the actuator based on the pitch angle;
• a control constant recording section for replacing the initial value of delivery test data with control constants inherent to the vehicle (A, B, C, D, W) which are written after attaching the headlamp to the vehicle and for recording them;
• a control constant determining section for determining whether the control constants inherent to the vehicle (A, B, C, D, W) are recorded to the control constant recording section;
• and
• a control stop section for stopping the control for the actuator when the control constants inherent to the vehicle (A, B, C, D, W) are not correctly recorded to the control constant recording section.