Exterior Mirror Head Position Sensing for Folded ADAS Alignment
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Solution Overview
Problem
Existing rearview mirror systems for vehicles face challenges in accurately determining the position of sensors mounted on pivotable mirror heads, which is crucial for advanced driver assistance systems (ADAS) and autonomous driving, as manual and power folding of the mirror head requires precise detection and transmission of position information to ensure reliable sensor data.
Innovation Solution
A positioning measurement system that uses a combination of magnetic, inductive, and optical sensors to accurately determine the rotational position of the mirror head relative to the mounting arm, allowing for precise calibration and operation of sensors, even when the mirror head is between the extended and folded positions, ensuring accurate data capture and processing for ADAS systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is installed on the pivotable mirror head to detect mirror head position, then the position detection capability is improved, but the complexity of the system increases due to additional components and wiring
Solution Approach 1:
The patent replaces mechanical position sensing methods with a magnetic field-based detection system. A magnet is attached to the mirror head and a magnetic field sensor is positioned in the mounting arm, eliminating the need for complex mechanical encoders or potentiometers while achieving accurate position detection through magnetic field strength variations.
Solution Approach 2:
The magnetic field sensor serves multiple functions: it detects mirror head position, determines whether the mirror is in folded or extended state, and provides data for actuator control. This multi-functional approach reduces system complexity by consolidating detection and control functions into a single sensing mechanism.
2Adaptability or versatility
If manual or power folding mechanism is used to pivot the mirror head, then the adaptability of the mirror system is improved, but the reliability of sensor data transmission deteriorates due to potential position detection errors during movement
Solution Approach 1:
The system implements continuous feedback by constantly monitoring the magnetic field strength as the mirror head moves during folding or extending. The controller receives real-time position data from the magnetic sensor and adjusts accordingly, ensuring accurate sensor data transmission throughout the entire range of motion and maintaining reliability during transitions.
3Ease of operation
If the mirror head is pivotable between folded and extended positions, then the ease of operation is improved, but the measurement precision of sensor position deteriorates due to varying distances and angles
Solution Approach 1:
The system accounts for parameter changes by calibrating the magnetic field detection across the full range of mirror positions. The controller stores calibration data for different angular positions and distance variations, allowing it to accurately determine mirror head position regardless of whether the mirror is folded, extended, or at any intermediate angle, thus maintaining measurement precision throughout the flexible range of motion.
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
The system provides high accuracy in determining the mirror head's position with a tolerance of less than 5 degrees, enabling reliable operation of ADAS and autonomous driving systems by ensuring sensors are calibrated and positioned correctly, thus improving the safety and effectiveness of vehicle surveillance and control.
Implementation Method 1
The positioning sensor collects sensor data representative of a magnetic field of the magnetic target at the positioning sensor to determine position of the magnetic target relative to the positioning sensor
Data Source
AI summary
A vehicular exterior rearview mirror system includes an exterior rearview mirror assembly having a mirror head pivotable relative to a mounting base. An actuator is operable to adjust the mirror head relative to the mounting base between a folded position and an extended position. The system includes a positioning sensor, a magnetic element, and an electronic control unit (ECU). The positioning sensor collects sensor data representative of a magnetic field of the magnetic element at the positioning sensor. The positioning sensor or the magnetic element is fixed relative to the mounting base and the other is pivotable with the mirror head relative to the mounting base. Based on processing at the ECU of captured sensor data and based on a determined magnetic field at the positioning sensor, the system determines a rotational position of the mirror head relative to the mounting base.