Vehicle Headlight Optical Axis Control at Low-Speed Stops
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Solution Overview
Problem
Existing vehicle headlight control systems struggle to accurately adjust the optical axis during low-speed conditions due to the delay in generating pulse signals from vehicle speed sensors, leading to improper axis setting when the vehicle is stationary.
Innovation Solution
A vehicle headlight control system that utilizes an acceleration sensor to determine the vehicle's stopping or non-stopping state by setting different reference values based on the type of vehicle, adjusting the optical axis accordingly using an optical axis adjustment unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vehicle speed sensor is used to determine stopping state, then the system can control optical axis adjustment during vehicle stoppage, but pulse signal generation is delayed at extremely low speeds causing inaccurate state determination
Solution Approach 1:
The patent replaces the mechanical/rotational vehicle speed sensor (which generates pulses based on axle rotation) with an acceleration sensor that directly measures linear acceleration. This substitution eliminates the delay caused by rotational inertia and pulse generation mechanics, enabling immediate and accurate detection of stopping state even at extremely low speeds.
Solution Approach 2:
The patent changes the detection parameter from rotational speed (pulse frequency from axle rotation) to linear acceleration. By using acceleration values directly from the acceleration sensor, the system can determine stopping state without waiting for rotational pulses to be generated, thus resolving the time delay issue at low speeds.
2Adaptability or versatility
If a single reference value is used for acceleration threshold, then the control logic is simplified, but accurate distinction between stopping and non-stopping states becomes difficult across different vehicle types
Solution Approach 1:
The patent makes the reference value dynamic rather than static. The control unit automatically adjusts the reference value based on detected vehicle type (engine vehicle vs. other vehicle), allowing the system to adapt to different vehicle characteristics without manual configuration or complex mechanical adjustments.
Solution Approach 2:
The patent changes the reference value parameter based on vehicle type detection. By setting different reference values for different vehicle types, the system achieves versatility across various vehicles while keeping the control logic relatively simple through automated parameter selection based on vehicle classification.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the accuracy of optical axis adjustment by accurately distinguishing between stopping and non-stopping states, ensuring proper headlight alignment regardless of low-speed delays in pulse signal generation.
Implementation Method 1
an acceleration sensor installed in the vehicle
Data Source
AI summary
To perform optical axis adjustment according to the state of a vehicle.A vehicle headlight control apparatus which controls an optical axis of irradiation light emitted by a headlight of a vehicle including: a specification unit that specifies a vehicle state; and an optical axis adjustment unit that receives results from the specification unit and adjusts the optical axis; where the specification unit: sets a reference value which pertains to an acceleration to a first value when the vehicle is an engine vehicle; sets the reference value to a second value which is smaller than the first value when the vehicle is not an engine vehicle; then specifies the vehicle state to be a stopping state when the acceleration detected by an acceleration sensor is smaller than the reference value; and specifies the vehicle state to be a non-stopping state when the acceleration is greater than the reference value.