Vehicle Pitch Angle Calculation via Acceleration Sensors
Solution Overview
Problem
Conventional methods for calculating a vehicle's pitch angle to adjust the optical axis of headlamps are costly and inefficient, especially when the road surface is inclined, as they rely on vehicle height sensors or require pre-stored inclination angles.
Innovation Solution
A pitch angle calculation device that uses acceleration sensors to detect accelerations in the longitudinal, vertical, and advancement directions of a vehicle, calculating the pitch angle using these measurements and adjusting the optical axis without relying on vehicle height sensors, even on inclined road surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vehicle height sensor is used to detect pitch angle, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical vehicle height sensor system with an electronic solution using acceleration sensors and gravitational force calculations. The pitch angle is derived by detecting the direction of gravitational force through acceleration sensors and calculating the angle relative to the vertical direction, eliminating the need for mechanical height sensors and their associated complexity.
Solution Approach 2:
The patent introduces gravitational force as an intermediary medium to indirectly measure pitch angle. Instead of directly measuring vehicle height or angle, the system uses acceleration sensors to detect gravitational force direction, then calculates pitch angle from this intermediate measurement, providing a simpler and more cost-effective solution.
2Adaptability or versatility
If pre-stored inclination angles are used for inclined roads, then adaptability is improved, but memory requirements and system complexity increase
Solution Approach 1:
The patent enables the system to self-determine road inclination in real-time using acceleration sensor data and gravitational force calculations. Instead of relying on pre-stored inclination angle data for different road conditions, the system continuously calculates the current pitch angle based on detected gravitational force direction, adapting automatically to any road condition without requiring memory storage of inclination data.
Solution Approach 2:
The patent transitions from a static approach (pre-stored inclination angles) to a dynamic approach (real-time calculation). The system continuously updates pitch angle measurements based on current acceleration sensor readings and gravitational force detection, allowing adaptive response to changing road conditions without requiring stored data for each possible scenario.
3Ease of manufacture
If acceleration sensors are used instead of vehicle height sensors, then cost is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent replaces expensive vehicle height sensors with cheaper acceleration sensors, using a fundamental physics principle (gravitational force detection) to achieve the measurement. This substitution maintains measurement precision by leveraging the constant and predictable nature of gravitational force, allowing cost-effective manufacturing without sacrificing accuracy.
Solution Approach 2:
The patent changes the measurement parameter from direct height or angle measurement to acceleration-based gravitational force detection. By measuring the direction of gravitational force through acceleration sensors and calculating pitch angle from this parameter, the system achieves accurate measurements using lower-cost sensors that detect acceleration rather than requiring expensive height sensing mechanisms.
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
Enables accurate and cost-effective calculation of pitch angles on both horizontal and inclined road surfaces, allowing for real-time adjustment of headlamp optical axes, including during stopped or constant-speed states, without the need for vehicle height sensors.
Implementation Method 1
an acceleration sensor 3 having a proof mass 32 which is movable in a predetermined direction
Data Source
AI summary
A pitch angle calculation device includes a first acceleration acquisition unit that acquires an acceleration Gx in a longitudinal axis (x) direction of a vehicle; a second acceleration acquisition unit that acquires an acceleration Gy in a vertical axis (y) direction of a vehicle; a third acceleration acquisition unit that acquires an acceleration α in an advancement direction of a vehicle; and a pitch angle calculation unit that calculates a pitch angle β formed between the longitudinal axis direction and the vertical axis direction by using the acceleration Gx, the acceleration Gy and the acceleration α.