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US 6,663,268 B1Granted
Automatic automotive headlamp leveling device
AssigneeKoito Manufacturing Co., Ltd.
InventorsAtsushi Toda, Hideaki Takeuchi
Life of this patent
Estimating the term…
Abstract
The invention provides an automatic automotive headlamp leveling device for providing a highly accurate optical axis correction by controlling the driving of an actuator without being affected by the mounting tolerance of a vehicle height sensor itself.
Claims13
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.
4 more elements
An automatic automotive headlamp leveling device comprising:
- actuators for vertically tilting optical axes relative to the body of a vehicle;
- a vehicle height sensor provided on a suspension of said vehicle for detecting a vertical distance between an axle and said body;
- and
- 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 arranged 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 position or rear-most end position 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 arithmetic control further adds a pitch angle corresponding to said offset value to said vehicle pitch angle calculated based on said predetermined expression and controls the driving of said actuators relative to said assumed initial positions based on said offset value added pitch angle.
6 more elements
An automatic automotive headlamp leveling device comprising:
- a reflector having a light source;
- an actuator having a movable shaft connected to said reflector for vertically tilting said reflector 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;
- and
- 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 said actuators based on said calculated pitch angle;
- wherein said control unit is arranged to operate said actuator by assuming to have the shaft of said actuator offset by a value corresponding to a maximum mounting tolerance of the height sensor.
3 more elements
An automatic automotive headlamp leveling device comprising:
- actuators for vertically tilting optical axes of a headlamp relative to a 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 and controlling the driving of said actuators based on said calculated pitch angle;
- and
- stable running time detecting means, wherein
- said control unit controls said actuators when the vehicle is stationary or when the vehicle is running stably at least for a predetermined period of time detected by said stable running time detecting means, and 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.
3 more elements
Dependencies are inferred from the claim text.