Patent ID: 6663268
Filing Date: 2003-12-16
Classification: B60Q

Abstract:
An automatic automotive headlamp leveling device comprising:actuators for vertically tilting optical axes of a headlamp relative to the body of a vehicle; a height sensor provided on a suspension of said vehicle for detecting a vertical distance between an axle and said body; a control unit for calculating a vehicle pitch angle corresponding to an output from said vehicle height sensor based on a predetermined expression and controlling the driving of said actuators based on said calculated pitch angle; wherein said actuators are each constructed so as to operate only in a direction in which said optical axes are lowered from a front-most end position or rear-most end position of a longitudinal stroke of said actuators in which the vehicle pitch angle is zero with said optical axes being in a predetermined inclined state relative to a road surface; said control unit is arranged to assume positions that are offset from said front-most end positions or rear-most end positions of said longitudinal strokes of said actuators by at least an amount of stroke corresponding to a maximum mounting tolerance in a direction in which said optical axes are lowered as initial positions of said actuators; and said control unit further subtracts an output corresponding to said offset value from an output from said vehicle height sensor, calculates a vehicle pitch angle corresponding to said offset value subtracted output based on said predetermined expression and controls the driving of said actuators relative to said assumed initial positions based on said pitch angle calculated as corresponding to said offset value subtracted output.